JP4401734B2 - Secondary battery internal resistance detection method, internal resistance detection device, internal resistance detection program, and medium containing the program - Google Patents

Description

The present invention relates to a secondary battery or at least one of a switching element for charging, a switching element for discharging, and a current value detecting element for charging / discharging that can be controlled on and off by a control circuit. Method for detecting internal resistance of secondary battery in mounted secondary battery pack, detection device, secondary battery pack having the detection device, machine having the detection device, internal resistance detection program, and program Related to the media.

Mobile devices such as portable personal computers, video cameras, digital cameras, mobile phones, and portable terminals are rapidly developing along with advances in semiconductor devices and the development of small, lightweight, high-performance secondary batteries. . Separately, predicted by the greenhouse effect due to an increase in CO ₂ gas amount in the atmosphere and global warming occurs, emissions of CO ₂ gas is advocated. For this reason, it has become difficult to construct a new thermal power plant that emits a large amount of CO ₂ gas, and measures to make effective use of the power generated by power generators such as thermal power plants. In other words, so-called load leveling is proposed in which nighttime power is stored in a secondary battery installed in a general household, and this is used during the daytime when power consumption is high to level the load. The development of electric vehicles that do not emit air pollutants and hybrid electric vehicles that combine a secondary battery that suppresses the emission of air pollutants and enhances fuel efficiency with an internal combustion engine or fuel cell are underway. Development of a high energy density secondary battery is expected as a secondary battery essential for these.

  In mobile devices, electric vehicles, and road conditioners that use the above-mentioned secondary batteries, the operating time can be maximized by managing the power on the device side according to the internal resistance of the secondary batteries used. Technology that can detect the internal resistance of the secondary battery accurately because it can obtain information on the life from the internal resistance of the secondary battery, know the replacement time of the battery and avoid sudden shutdown. It has become extremely important. Further, in mobile devices, electric vehicles, and road conditioners, at least one of a charging switching element, a discharging switching element, and a charge / discharge current value detection element that can be controlled on and off by a control circuit is a charging / discharging path of the secondary battery. In many cases, a secondary battery pack interposed in the battery is used, and in the secondary battery pack, internal resistance information of the entire secondary battery pack due to abnormality or deterioration of each element as in the case of the internal secondary battery. It is equally important to detect.

As one of such internal resistance detection methods,
Japanese Patent Application Laid-Open No. 9-134742 discloses a method of measuring the internal impedance immediately before the end-of-discharge voltage by passing an alternating current through the storage battery with an impedance measuring instrument. However, since the method described in Patent Document 1 requires a measuring device that generates an alternating current and measures impedance, the measurement device becomes large and measurement is performed while the secondary battery is used. This is not practical because there is a problem that the measured impedance does not necessarily match the internal resistance R detected as the voltage drop (IR loss) amount during charging / discharging. Japanese Patent Application Laid-Open No. 2002-142379 discloses a method of detecting internal resistance from the amount of voltage drop during pulse charging. However, the method described in Patent Document 2 requires a specific operation that is different from that of a charger that is used for general purposes. In addition, although there is a difference depending on the pulse width (time), generally, in the pulse charging, The voltage rise from the open circuit voltage with respect to the charging current value in the charging period is lower than that in the case of continuous charging, and the battery voltage in the rest period does not decrease to the open circuit voltage. If the internal resistance is detected from the difference, there is a problem that the value is smaller than the internal resistance R detected as a voltage drop (IR loss) amount during charging and discharging. Japanese Patent Application Laid-Open No. 7-240235 discloses a method of detecting the internal resistance from the amount of voltage drop at which charging is interrupted. However, the method described in Patent Document 3 is similar to the method described in Patent Document 2, and in addition to requiring a specific operation different from a general-purpose charger, an accurate voltage drop amount is also required. In order to measure the time, a long pause period is required, which increases the time required for full charge, which is inconvenient and deteriorates work efficiency.

In order to solve the above problems, the present inventors have
In Japanese Patent Application Laid-Open No. 2002-50410 (P2002-50410A), in a normal secondary battery, an open circuit voltage expressed as a function of the storage amount of the battery, an internal resistance expressed as a function of the storage amount, temperature, and current, A method for predicting and detecting the internal state of the battery, such as the amount of charge and the internal resistance, from the voltage of the battery to be detected and the flowing current has been proposed. Although the above detection method can predict the internal state of the battery with extremely high accuracy, it is necessary to acquire basic data of the battery under various conditions in advance, and therefore it is necessary to pay a great deal of effort.

  The present invention solves the problems in the above-described conventional method of detecting the internal resistance of a secondary battery, and does not require a specific operation during charging or a special time for detection. It is an object to provide a method and apparatus for detecting the internal resistance of the machine with high accuracy, and various mechanical devices to which the method and apparatus are applied.

SUMMARY OF THE INVENTION The present invention solves the above-described problem, and includes at least one of a secondary battery to be detected, a charging switching element that can be turned on / off by a control circuit, a discharging switching element, and a charging / discharging current value detecting element. Provided is a method for accurately detecting the internal resistance of the secondary battery (that is, the secondary battery to be detected) in a secondary battery pack in which two or more are interposed in the charging / discharging path of the secondary battery. The internal resistance detecting method of the detected secondary battery of the present invention is typically after the battery voltage starts charging with a constant current value I ₀ reaches a predetermined voltage V _max, a predetermined voltage V _max When charging is performed by a constant current-constant voltage charging method consisting of a combination of a constant current charging mode and a constant voltage charging mode in which charging is performed until the end of charging, the amount of charge in the detected secondary battery in the constant voltage charging mode is Step (a) to be obtained and the internal resistance when the internal resistance of a normal secondary battery with no decrease in storage capacity corresponding to the detected secondary battery is increased or decreased, or the increase or decrease in internal resistance It has a step (b) which refers to the relationship of the amount of charge of the normal secondary battery in the constant voltage charging mode. In the method for detecting the internal resistance of the detected secondary battery according to the present invention, the storage capacity of the detected secondary battery decreases to D times the storage capacity of the normal battery (D is a constant, 0 <D ≦ 1). If the charge electric quantity of the detected secondary battery in the voltage charging mode obtained in the step (a) is multiplied by 1 / D, then the internal resistance or the increase or decrease in the internal resistance described in the step (b) It includes a mode in which the internal resistance of the detected secondary battery is predicted and detected by referring to the relationship of the amount of charged electricity in the constant voltage charging mode with respect to the minute. Note that “detection” in the present invention includes estimation and prediction based on reference data.

  Further, the present invention provides a secondary battery charge / discharge path for a secondary battery (at least one of a switching element for charging, a switching element for discharging, and a current value detecting element for charge / discharge that can be controlled on and off by a control circuit). A device for predicting and detecting the internal resistance of the secondary battery pack included in the battery pack (including the secondary battery) is provided. The internal resistance detection device according to the present invention includes at least means for detecting a voltage of a detected secondary battery, means for detecting a current flowing through the detected secondary battery, and a constant voltage charging mode in a constant current-constant voltage charging system. Means for determining the amount of charged electricity of the detected secondary battery, the normal with respect to the internal resistance or the increase / decrease in the internal resistance acquired in advance for a normal secondary battery without a decrease in the storage capacity corresponding to the detected secondary battery Means for storing the relationship between the amount of charge in the constant voltage charging mode of the secondary battery, and the detected secondary from the amount of charge in the detected battery in the constant voltage charging mode with reference to the information in the storage It has a means for predicting and detecting the internal resistance of the battery. In the internal resistance detection device according to the present invention, when the storage capacity of the detected secondary battery is reduced to D times the storage capacity of the normal battery (D is a constant, 0 <D ≦ 1), the constant voltage After the charge electricity amount of the detected secondary battery in the charge mode is multiplied by 1 / D, the internal resistance of the detected secondary battery is determined from the charge electricity amount in the constant voltage charge mode with reference to the information in the storage means. It further includes a means for detecting, and includes an aspect for detecting the internal resistance of the detected secondary battery from the output of the detecting means.

  Furthermore, the present invention provides a secondary battery pack characterized by having one or more secondary batteries to which the internal resistance detection device described in paragraph 0008 is added. The present invention also provides a mechanical device comprising the internal resistance detection device described in paragraph 0008. The mechanical device is an inspection device for inspecting whether a manufactured secondary battery is a good product or a defective product, a charger for charging a secondary battery, a portable device such as a mobile phone, a portable terminal, a portable computer, an automobile, It includes a mechanical device selected from a moving body such as a motorcycle, a ship, an aircraft, and a spacecraft. Furthermore, the present invention provides an internal resistance detection program for a secondary battery characterized by incorporating the internal resistance detection method for a detected secondary battery according to the present invention described in paragraph 0007, and a storage medium storing the program. To do.

  As a secondary battery to which the internal resistance detection method, the internal resistance detection device, the internal resistance detection program and the medium containing the program of the secondary battery according to the present invention can be applied, a secondary battery charged by a constant current-constant voltage charging method is used. It is a battery. A preferable example of such a secondary battery is a lithium secondary battery (including a lithium ion secondary battery) using a redox reaction of lithium, but is not limited thereto.

  According to the present invention, it is possible to detect the internal resistance of the secondary battery to be detected with high accuracy by a simple method from measurement of the amount of charge in the constant voltage charging mode in the constant current-constant voltage charging method. it can. The detected secondary battery is a secondary battery housed in a secondary battery pack. The secondary battery pack includes a charging switching element, a discharging switching element, and a charging / discharging element that can be controlled on and off by a control circuit. Even if at least one of the current value detection elements is interposed in the charge / discharge path, it can be detected with high accuracy. In addition, since the internal resistance of the secondary battery to be detected can be detected with high accuracy in this way, power management of devices and devices that use the secondary battery as a power source becomes easy, and the timing of battery replacement can be set. It is possible to know easily. Therefore, the performance of the secondary battery can be maximized by adding the internal resistance detection device using the internal resistance detection method of the present invention to a battery pack, a charger, or a device using the secondary battery as a power source. The performance of the equipment can be maximized. In addition, by adding the internal resistance detection device to an inspection device for inspecting a non-defective product or a defective product before shipment of the manufactured secondary battery, a highly accurate shipment inspection can be performed.

  Hereinafter, the secondary battery to be detected of the present invention (at least one of the switching element for charging, the switching element for discharging, and the current value detecting element for charging / discharging which can be controlled on and off by the control circuit is a charging / discharging path of the secondary battery An example of the internal resistance detection method (including the secondary battery in the secondary battery pack interposed therebetween) will be described with reference to the drawings. However, the internal resistance detection method of the present invention is not limited to this.

FIG. 1 is a flowchart showing an example of a method of detecting the internal resistance of a secondary battery to be detected according to the present invention when charging is performed by a constant current-constant voltage charging method. Note that S in S1 to S9 in FIG. 1 represents a step, and the numeral represents a step number. As a detection start, charging of the detected secondary battery is first started in step 1. The constant current charging in step 2 switches to the constant voltage V _max charging in step 4 when the battery voltage in step 3 reaches the predetermined voltage V _max , and simultaneously starts measuring the charging current value and time in step 5. . When the charging end condition in step 6 is satisfied, the charging in step 7 is terminated. Next, from the measurement of the charging current value and time in step 5 above, the charge electricity amount in the constant voltage charging mode is calculated in step 8. In step 9, refer to the relationship between the amount of charge in the constant voltage charge mode and the internal resistance or the increase / decrease in internal resistance prepared in advance for a normal secondary battery corresponding to the detected secondary battery with no reduction in storage capacity In addition, the internal resistance of the detected secondary battery can be detected.

There is a one-to-one correspondence between the amount of charged electricity in the constant voltage mode and the internal resistance of the battery to be detected without a decrease in capacity, and the internal resistance value can be predicted by measuring the amount of charged electricity in the constant voltage mode. The reason is as follows.
Here, as a definition of terms, the storage capacity (= full charge amount) refers to the maximum amount of electricity that the battery can store. The storage capacity (= full charge amount) of the secondary battery is the total amount of electricity that can be discharged from a fully charged state to a discharge depth of 100% (a state where discharge is impossible). That is, an area surrounded by a discharge current curve and a time axis in which the discharge current value is plotted with respect to the discharge time, which is a value integrated with the discharge current time when discharged from a fully charged state. Further, if the amount of electricity used for charging is almost 100% stored in the battery, the amount of electricity charged from the discharge depth of 100% to the fully charged state becomes the storage capacity (= full charge amount). In charging by the constant current-constant voltage charging method, the time when full charging is reached is the time when charging current hardly flows in the constant voltage charging mode.

    The storage capacity (= full charge amount) of the detected secondary battery without any decrease in the storage capacity (internal resistance may be increased) is the storage capacity of the normal battery corresponding to the detected secondary battery (= It is equal to (full charge amount). Therefore, in the detected secondary battery in which only the internal resistance is increased, the area surrounded by the charging current curve and the charging time axis is equal to that of a normal secondary battery. On the other hand, when a secondary battery to be detected is charged with the above-described constant current-constant voltage charging method from a discharge depth of 100% to full charge, a normal battery that has no decrease in storage capacity but has an internal resistance value that is larger than that of a normal battery and is large Compared to the battery, the charging time in the constant current charging mode is shortened, the constant voltage charging mode is reached earlier, and the constant voltage charging time is lengthened. That is, the amount of charge until the battery with increased internal resistance is fully charged in the constant current charging mode increases as the internal resistance increases. This means that the internal resistance value of the battery can be predicted if the amount of electricity charged until the battery is fully charged in the constant current charging mode without a decrease in the storage capacity is known. According to this method, even in the case of so-called additional charging in which a battery with a remaining amount of electricity is charged, if the charging starts from constant current charging, the internal resistance value can be estimated.

  In the present invention, since the internal resistance of the secondary battery to be detected can be estimated from the amount of charge in the constant voltage charging mode in the constant current-constant voltage charging method, the constant current charging mode from the discharge depth of 100% can be estimated. Even when charging is not performed, that is, when the amount of electricity to be charged is not added, that is, when the secondary battery to be detected remains charged, the internal resistance of the secondary battery to be detected can be predicted and detected. In the present invention, “discharge depth of 100%” means a state where the amount of electricity can no longer be taken out unless otherwise specified, that is, the amount of electricity that can be taken out due to a sudden drop in battery voltage even if the previous discharge is continued. This means a state where there is almost no increase.

    The main feature of the present invention that the internal resistance value can be predicted from the amount of charged electricity in the constant voltage mode when there is no decrease in the storage capacity of the secondary battery is that the normal battery of the present inventors is external to the normal battery. It was discovered by the following simulation experiment in which a resistor was connected to create a battery with only the internal resistance increased and a constant current-constant voltage charge was performed.

[Experimental example of acquisition of relational data of charge amount in constant voltage charge mode with respect to internal resistance or increase / decrease in internal resistance]
In the present invention, in order to detect information related to the internal resistance of the secondary battery to be detected, an example of an experiment in which relational data on the amount of charge in the constant voltage charging mode with respect to the internal resistance or the increase / decrease in the internal resistance could be obtained. This will be described with reference to FIGS.
For the secondary battery only the internal resistance is increased rather than decreased the storage capacity, in order to know the charging characteristic what transition to artificially connect a resistor r _S in series with the secondary battery The internal resistance was increased, the constant current-constant voltage charging operation was performed, and the transition of the charging voltage and charging current and the amount of charged electricity were observed. Next, after a predetermined discharging operation, constant current charging was performed, and the internal resistance when a predetermined voltage was reached was measured.

FIG. 9 is a circuit diagram in which a resistor r _s is connected to a normal secondary battery (a portion surrounded by a wavy line portion) whose internal resistance is R ₁ and connected to a charge / discharge device. The resistance value of the resistor r _s corresponds to an increase in internal resistance of the secondary battery, and is preferably on the same order as R ₁ . In FIG. 9, when a commercially available lithium ion secondary battery having a diameter of 18 mm and a height of 65 mm and a nominal capacity of 1680 mAh is used as the secondary battery and the resistor r _s is not connected, the resistance values are 27 mΩ, 39 mΩ, and 62 mΩ. When a resistor r _{s of} 91 mΩ, 110 mΩ, and 150 mΩ is connected, a constant current charge of 1.7 A is performed from a discharge depth of 100%, and when the charging voltage reaches 4.2 V, 4. FIG. 10 is a diagram showing the charging voltage with respect to the charging time when charging is performed at a constant voltage of 2 V and charging is terminated when the charging current in the constant voltage charging mode decreases to 0.1 A. FIG. 11 shows a charging current with respect to). FIG. 12 shows a constant current charging at a discharge depth of 100% to 1.7 A in order to examine the open circuit voltage when the charging voltage is 4.2 V when the secondary battery is used and the resistor r _s is not connected. It is the figure which showed the battery voltage with respect to the elapsed time of 90 minutes after completion | finish of charge when it complete | finishes and it complete | finishes when the charge voltage reaches | attains 4.2V. As will be described later, FIG. 12 was used to calculate the internal resistance from the difference between the battery voltage and the open circuit voltage and the charging current value.

From the charging voltage curve with respect to the charging time in FIG. 10, as the resistance value connected in series increases, the time to reach a predetermined voltage, that is, the charging time at a constant current is shortened, and is determined at an early stage after the start of charging. It turns out that it transfers to charge of a voltage. Further, from the charging current curve with respect to the charging electricity amount in FIG. 11, the charging electricity amount in the constant voltage charging mode increases as the resistance value connected in series increases, but the accumulated charging amount until the end of charging (full charging). Was a value almost the same as the storage capacity in the range of 1655 to 1670 mAh (98.5% to 99.4% with respect to the nominal capacity of the secondary battery). The obtained integrated charge amount appears to decrease as the resistance value of the connected resistor increases, but when the charge current value reaches 0.1 A, the charging is terminated. Because it is. The smaller the resistance value of the connected resistor, the greater the decay of the charging current in the constant voltage charging mode, so if the charging is continued at a constant voltage for a sufficient time so that the charging current becomes almost zero, the connection Regardless of the resistance value of the resistor, the charge amount is considered to be almost constant. Therefore, it can be seen that even if the resistor r _s is connected in series with the secondary battery to increase the internal resistance in a pseudo manner and the constant current-constant voltage charging operation is performed, the storage capacity of the secondary battery itself does not change.

Moreover, it can be seen from the battery voltage curve of FIG. 12 that the battery voltage gradually decreases after the constant current charging of 1.7 A, and converges to a certain voltage value after a predetermined time. This voltage value is considered the open circuit voltage Voc. The battery voltage Vc at the time of charging is represented by the following formula (1) of the relationship between the open circuit voltage Voc, the charging current I, and the internal resistance R of the battery,
Vc = Voc + I × R ---- (1)
Assuming that the internal resistance R of the secondary battery is R ₁ , R ₁ is a value obtained by dividing the difference between the charging voltage of 4.2 V and the open circuit voltage at that time by the charging current value of 1.7 A. It can be calculated from (2).
R _I (Ω) = (4.2V−Voc) /1.7A ---- (2)
Similarly, when the resistor r _s was connected, the internal resistance R (= R ₁ + r _s ) was calculated.

The results obtained above are summarized in Table 1. In Table 1, with respect to the resistance value of the resistor connected to the battery, the accumulated charge amount from 100% depth of discharge when the charge current is reduced to 0.1 A , the accumulated charge amount in the constant voltage mode (CV charge amount) ), The open circuit voltage when the battery voltage reaches 4.2 V, and the resistance value (calculation R) calculated from the above equation (2) are collectively shown. In Table 1, the open circuit voltage is measured and the resistance value (calculated R) of the battery or the battery connected to the resistor is calculated from equation (2). If an external measuring device can be used, an LCR meter, etc. It may be obtained by directly measuring with.

    FIG. 13 shows the relationship between the charge electricity quantity in the constant voltage charge mode with the calculated R shown in Table 1 as the internal resistance value. From FIG. 13, it can be seen that various internal resistance values created in a simulated manner by connecting a resistor to the battery have a one-to-one correspondence with the amount of charge in the constant voltage charging mode. From the results in Table 1, it can be seen that the calculated R of the battery with the resistor connected substantially matches the calculated R value of the battery body without the resistor connected to the sum of the resistance values of the resistors. In other words, it is not necessary to calculate or measure the resistance value of the battery to which the resistor is connected. If the resistance value of the battery body before connecting the resistor is obtained, the resistance value of the connected resistor can be calculated from the resistance value of the connected resistor. It shows that the resistance value of the battery connected to the battery can be easily calculated. Therefore, after measuring the internal resistance of the battery without a decrease in storage capacity, connect various resistors, perform constant current-constant voltage charging, and acquire in advance the data that measures the accumulated charge electricity in constant voltage mode By doing so, if there is no reduction in the storage capacity of the battery to be detected, the internal resistance value of the battery to be detected can be estimated from the measurement of the accumulated charge amount in the constant voltage mode.

Here, as an example of the function equation R (Q) of the approximate curve of the relationship of the internal resistance R (mΩ) to the charge electricity quantity Q (mAh) in the constant voltage charging mode, the constant voltage is expressed as the following expression (3) It was assumed that it can be expressed as a function of the charge electricity quantity Q in the charge mode.
R (Q) = P _n × Q ⁿ + P _n-1 × Q ^n-1 + P _n-2 × Q ^n-2 + ・ ・ ・ + P ₁ × Q ¹ + P ₀ × Q ⁰ ---- (3)
In Equation (3), P _n to P ₀ are constants that vary depending on the type, model, nominal capacity, and the like of the secondary battery.

In this example, it is assumed that the internal resistance R is expressed by a third-order polynomial of the charge electricity quantity Q in the constant voltage charging mode, and a commercially available lithium ion secondary having a size of 18 mm in diameter and 65 mm in height and a nominal capacity of 1680 mAh. For the battery, based on the acquired basic data, a function expression of the internal resistance R (mΩ) with respect to the charge amount Q (mAh) in the constant voltage charge mode was calculated from the curve fitting of FIG. The calculated function formula is as follows.
R (Q) = 0.000000072 × Q ³ −0.0002580011 × Q ² + 0.4205795841 × Q + 7.825572664 ---- (4)
Even if the measurement data is the same type and the same type of secondary battery, there are individual differences. Therefore, it is preferable to use data obtained by averaging data obtained from a plurality of secondary batteries.
In this example, the function expression of R (Q) is represented by a third-order polynomial of the charge electricity quantity Q in the constant voltage charge mode. However, in the present invention, it is limited to the order of these polynomials. It is not something. Further, these functional expressions are not limited to n-order polynomials. Furthermore, in this example, the relationship of the internal resistance R (mΩ) to the charge amount of electricity Q (mAh) in the constant voltage charging mode has been described as a function expression of an approximate curve, but this relationship may be expressed as a data table. I do not care.

    Usually, in a secondary battery, the storage capacity gradually decreases due to repeated charge / discharge and changes over time. In the flow of predictive detection of the internal resistance of the secondary battery of the present invention in FIG. 1, if it is known that there is no decrease in the storage capacity, the internal resistance can be estimated correctly, but the decrease in the storage capacity is not known Therefore, it is necessary to make a correction by estimating the decrease in the storage capacity.

    FIG. 2 shows a case where the storage capacity of the detected secondary battery is reduced to D times the storage capacity of a normal battery corresponding to the detected secondary battery (D is a constant, 0 <D ≦ 1). An example in the case of implementing the internal resistance detection method of this invention in the process of constant current-constant voltage charge is shown with the flowchart. As shown in FIG. 2, it is possible to determine the internal resistance more accurately by correcting the decrease in the storage capacity. Note that S in S1 to S10 in FIG. 2 represents steps as in FIG. 1, and numerals represent step numbers. 2 is the same as that described in FIG. 1 from step 1 to step 8, and after multiplying the charge electricity amount in the constant voltage charging mode obtained in step 9 in step 9 by 1 / D, FIG. As in the case, the detected secondary battery is referred to by referring to the relationship between the internal resistance prepared in advance for the normal secondary battery in step 10 or the amount of charge in the constant voltage charging mode with respect to the increase / decrease in internal resistance. The internal resistance can be detected. This is because the relationship between the internal resistance value to be referred to and the amount of charged electricity in the constant voltage charging mode relates to a battery in which the storage capacity does not decrease.

By the way, the following is mentioned as a method of calculating | requiring the said electricity storage capacity fall rate D simply. When the secondary battery is charged by the constant current I ₀ -constant voltage V _max charge, the secondary battery is predetermined from the time of switching from the constant current I ₀ charge mode to the constant voltage V _max charge mode in the detected secondary battery. When the time until the current value I _M becomes t _M ′, the amount of charge in the constant voltage charging mode is Q _CV ′, and the normal secondary battery has t _M and Q _CV respectively,
Relational expression D = (Q _CV '−I ₀ × t _M ') / (Q _CV −I ₀ × t _M ) (5)
Thus, the reduction rate D of the storage capacity when the storage capacity of the normal battery is 1.0 can be calculated.
The storage capacity (full charge amount) of a battery whose D storage capacity is D times that of a normal battery (0 <D ≦ 1) is the same as the normal storage capacity (full charge amount) of 1 / D times. Become. If the discharge amount relative to the charge amount is 100%, the full charge amount is the integrated charge electricity amount from the discharge depth of 100%, the value obtained by integrating the charge current value flowing through the battery over time, that is, the elapsed time with the charge current as the vertical axis. Is the area surrounded by the charging current curve and the time axis. Therefore, even if the storage capacity is unknown, the area surrounded by the charging current curve obtained by multiplying the charging current curve of the battery by 1 / D in the time axis direction and the time axis is normal battery charging. It becomes equal to the area surrounded by the current curve and the time axis, and the above equation (5) is derived from this relationship.
The reason why such detection is possible will be described with reference to Experimental Example 1 below.

Experimental example 1

  FIG. 3 shows a commercially available lithium ion secondary battery having a diameter of 18 mm, a height of 65 mm, and a nominal capacity of 1680 mAh, from a discharge depth of 100% to 84 mAh at a constant current of 0.34 A (this secondary battery nominal 5% of capacity) After charging, the intermittent charging operation of stopping for 3 hours is repeated until the charging voltage reaches 4.2V, and after reaching 4.2V, the charging current value is 0.1A by constant voltage charging of 4.2V. It is a figure which shows the charge characteristic at the time of complete | finishing at the stage where it reduced below, and a horizontal axis is time and a vertical axis | shaft is battery voltage.

    FIG. 4 shows the relationship between the battery voltage with respect to the accumulated charge obtained in FIG. 3 and the battery voltage at the time of charging suspension (= open circuit voltage). In FIG. 4, the dotted line indicates a trace of the open circuit voltage during pause after intermittent charging. The solid line indicates the battery voltage during charging, and the corner of the curve indicates the charging. This represents the point in time when the operation was stopped and the operation was stopped. In FIG. 4, the accumulated charge amount at the end of charging is 1687 mAh, which is the storage capacity equal to the nominal capacity of the secondary battery. Therefore, the dotted voltage curve in FIG. 4 shows the relationship between the accumulated charge amount (= charge amount) of this battery and the open circuit voltage, the horizontal axis is the charge amount, and the vertical axis is the battery voltage. It can be seen from FIG. 4 that the circuit voltage reflects the charged amount. Since the open circuit voltage does not depend on the internal resistance of the battery, even if the battery has an increased internal resistance, if the storage capacity does not decrease, the relationship between the storage amount and the open circuit voltage is the same as that of a normal battery. Means that.

  FIG. 5 shows the open circuit voltage curve of the dotted line in FIG. 4 by a solid line, and in the same manner as above, a secondary battery having the same type and the same type as that of a normal secondary battery and having been subjected to cycle deterioration 200 times in advance. The relationship between the amount of stored electricity and the open circuit voltage is obtained and indicated by a broken line. The accumulated charge amount (= charge amount) at the end of charging of the cycle-deteriorated secondary battery is 1419 mAh, which is 0.84 times the nominal capacity of a normal secondary battery. The dotted line in FIG. 5 is obtained by multiplying the charged amount of the cycle-deteriorated secondary battery and the charged amount that is the horizontal axis of the voltage curve (broken line) of the open circuit voltage by 1 / 0.84 times (1.19 times), The amount of charge of a normal secondary battery and the voltage curve (solid line) of the open circuit voltage almost coincide. Therefore, the storage capacity of the secondary battery that has deteriorated to D times the storage capacity of the normal secondary battery and the voltage curve of the open circuit voltage are 1 / D times the storage capacity regardless of the internal resistance of the secondary battery. By doing so, it can be matched with that of a normal secondary battery or a battery in which only the internal resistance without a decrease in the storage capacity is changed. In other words, only the normal secondary battery or the internal resistance is obtained by multiplying the characteristic expressed as a linear function of the secondary battery that has deteriorated to D times the storage capacity of the normal secondary battery by 1 / D times. Indicates that the characteristics of the changed battery can be expressed.

  FIG. 6 shows that the normal secondary battery and the cycle-degraded secondary battery are each subjected to constant current-constant voltage charging with a constant current of 1.7 A and an upper limit voltage value of 4.2 V from a discharge depth of 100%. The charging characteristics when the charging current value during voltage charging is 0.1 A or less are indicated by a solid line for a normal secondary battery, a broken line for a cycle deteriorated secondary battery, and a side of the cycle deteriorated secondary battery. It is a figure which shows what 1 / D = 1 / 0.84 time (1.19 time) of the axis | shaft (time), a horizontal axis is time and a vertical axis | shaft is a charging current value. The area surrounded by the charging current curve and the charging time axis in FIG. 6 is the amount of charge electricity, and in the secondary battery whose storage capacity is D times that of the normal secondary battery, the charging current curve and the charging time axis are shown. The area surrounded by is D times that of a normal secondary battery. This is because the charging current curve of the secondary battery whose storage capacity is D times that of a normal secondary battery is multiplied by 1 / D in the charging time axis direction, and the area surrounded by the charging current curve and the charging time axis is If it is 1 / D times, it means that it is equal to that of a normal secondary battery. As can be seen from the comparison between the solid line and the dotted line in FIG. 6, the area surrounded by the 1 / D times the charging current curve and the charging time axis (full charge amount) is the same as that of a normal battery, but the charging curve Do not match, and the amount of charge in the constant voltage charging mode is large. This shows a charging curve when only the internal resistance increases in view of FIG. That is, if the charging current curve in the constant current-constant voltage charging of the battery having a reduced storage capacity is multiplied by 1 / D in the time axis direction, it can be converted into a charging current curve in which only the internal resistance is increased.

  Therefore, when the storage capacity of the detected secondary battery is reduced to D times the storage capacity of a normal secondary battery corresponding to the detected secondary battery (D is a constant, 0 <D ≦ 1), After the charge amount of the detected secondary battery in the voltage charging mode is multiplied by 1 / D, the internal resistance prepared in advance for the normal secondary battery or the increase / decrease in the internal resistance in the constant voltage charging mode By referring to the relationship between the amount of charged electricity, the internal resistance of the secondary battery to be detected can be detected.

Here, the D value, which is the ratio of the storage capacity of the detected secondary battery to the storage capacity of the normal secondary battery, can be obtained by the following method. First, the full charge amount C, C ′ of each of the normal battery and the detected battery corresponding to the detected battery, or the total discharge amount C, C ′ up to a discharge depth of 100% from the fully charged state is measured. Next, D = C ′ / C is obtained by calculating the ratio of the full charge amount C ′ of the detected battery to the full charge amount (= storage capacity) C of the normal battery. (The full charge amount C of a normal battery may be replaced with a nominal capacity.) In addition, when charging by a constant current I ₀ -constant voltage V _max charging method, a normal battery and a detected secondary battery , T _M , t _M 'from when the constant current I ₀ charging mode is switched to the constant voltage V _max charging mode until the predetermined current value I _M , and charging in the constant voltage charging mode Measure the quantity of electricity Q _CV , Q _CV 'and calculate the D value from Eq. (5) where D = (Q _CV'- I ₀ × t _M ') / (Q _CV -I ₀ × t _M ) Can do. In this calculation method, the area surrounded by the time axis and the charging current curve obtained by multiplying the charging current curve of the battery whose capacity is reduced in FIG. 6 by 1 / D is surrounded by the charging current curve and the time axis of a normal battery. It is derived using the fact that it is equal to the area.
According to this latter method, by using the information on the charging current value and the amount of charge in the constant voltage charging mode, the D value can be easily obtained with high accuracy without actually measuring the full charge amount. It can be calculated. The above I _M is more preferably ½ of I ₀ .

[Charge electricity in constant voltage charging mode]
In the constant current-constant voltage charging method according to the present invention, the “charging electric quantity in the constant voltage charging mode” is any one of the following three states (i), (ii), and (iii) from the time of transition to constant voltage charging. It is good also as the amount of charge electricity until it reaches the point of time. In addition, the charging method in the present invention may be a constant current-constant voltage charging method under a charging termination condition in which charging is terminated at the time of (i), (ii), and (iii).
(I) When the charging current in the constant voltage charging mode reaches a predetermined current value I _min ,
(Ii) when the charge current in the constant voltage charging mode after a predetermined current value I _n reached a predetermined time has elapsed t _n, or
(Iii) after the lapse of the predetermined time t _f from the constant voltage charging transition point. (The predetermined time t _f is an elapsed time when the charging current becomes sufficiently small, and is a value determined by a test made in advance. Of course, in charging with the constant current-constant voltage charging method, the constant current charging start time is started. (The elapsed time from the point may be t _f .)
The reason why the amount of electricity charged in the constant voltage mode at the time of (i), (ii), and (iii) above can be almost regarded as the amount of electricity charged in the constant voltage mode until reaching the fully charged state is that (i), (ii ) And (iii), the charging current is already small enough, and even if the charging is continued until the time when the charging current becomes almost zero after that point, the increase in the amount of charge is small. This is because the influence (generated error) on the estimation of the internal resistance in the present invention is small and can be ignored.

[Internal resistance detection device for secondary battery]
Hereinafter, the secondary battery to be detected of the present invention (at least one of a switching element for charging, a switching element for discharging, and a current value detecting element for charging / discharging that can be controlled on and off by a control circuit is a charging / discharging path of the secondary battery. An example of an internal resistance detection device for detecting the internal resistance of the secondary battery pack interposed in the battery pack will be described with reference to the drawings. The internal resistance detection device of the present invention is not limited to this.

FIG. 7 schematically shows a configuration of a main part of an example of the internal resistance detection device of the present invention for detecting the internal resistance of the secondary battery to be detected when charging is performed by the constant current-constant voltage charging method. It is a thing. The internal resistance detection device of the present invention shown in FIG. 7 basically includes a terminal 701 for connecting a detected secondary battery to the device, a battery voltage detection unit 702 for detecting a voltage between terminals of the detected secondary battery, It comprises a charging current detector 703 that detects the charging current of the detected secondary battery, and a controller 704.
Here, the terminal 701 makes it possible to easily and reliably electrically connect the secondary battery to be detected to the apparatus main body. The battery voltage detection unit 702 detects the voltage between the positive and negative terminals of a secondary battery to be detected, which is charged with a constant current and a constant voltage, by a charger (not shown) with high input impedance. The data is output to the control unit 704. The charging current detection unit 703 detects the charging current of the detected secondary battery with low input impedance, and this current value information is output to the control unit 704.

  The control unit 704 has a timer (counter) and a calculation unit inside or outside thereof. From the voltage information obtained from the battery voltage detection unit 702, the control unit 704 switches from the constant current charging mode to the constant voltage charging mode, measures the charging time from the switching time with a timer (counter), and detects the charging current. Based on the current value information obtained from the unit 703 and the charging time information obtained from the timer (counter), the calculation unit obtains the amount of charge in the constant voltage charging mode. Further, the control unit 704 has a memory inside or outside as a storage unit. The memory stores the relationship of the amount of charge in the constant voltage charging mode with respect to the internal resistance of the normal secondary battery corresponding to the detected secondary battery or the increase or decrease of the internal resistance. The control unit 704 refers to the information stored in the storage unit, calculates the amount of charged electricity in the constant voltage charging mode calculated by the calculation unit, and estimates the internal resistance of the detected secondary battery. The internal resistance detection device of the present invention shown in FIG. 7 can be connected to a detected secondary battery in which constant current-constant voltage charging is performed as a single device, and perform the above-described detection operation. The power supply of the apparatus main body required at this time is not shown, but can be taken in from a charger or a connected secondary battery to be detected in addition to being supplied from the outside.

  FIG. 8 is a circuit configuration diagram showing an example of a secondary battery pack to which the internal resistance detection device of the present invention is added. In the internal resistance detection device that uses the secondary battery in the secondary battery pack as the detected secondary battery, the charging positive terminal and the negative terminal of the secondary battery pack are connected to the terminal 701 of the device described in FIG. Further, as shown in this example, an internal resistance detection device that uses the secondary battery pack as a detected secondary battery can be added inside the secondary battery pack.

  The secondary battery pack shown in FIG. 8 includes a secondary battery 801, a positive terminal 802 and a negative terminal 803 of the secondary battery pack, a positive terminal for charging 804 (the negative terminal for charging also serves as the negative terminal), and a battery voltage monitor. An overdischarge protection element comprising an output terminal 805, a battery voltage detection unit 806 for detecting a voltage between terminals of the secondary battery pack, a charging current detection unit 807 for detecting a charging current of the secondary battery pack, a MOSFET with a parasitic diode, and the like 808, an overcharge protection element 809, and a control unit 810. Note that the secondary battery pack shown in FIG. 8 has one secondary battery, but the number of secondary batteries constituting the secondary battery pack is not limited to this, and a plurality of secondary batteries are included. It may be.

  Here, the battery voltage detection unit 806 detects the voltage between the secondary battery pack positive terminal 802 and the negative terminal 803, which are detected secondary batteries that are charged with constant current-constant voltage, by a charger (not shown). The voltage information is output to the control unit 810. The charging current detection unit 807 detects the charging current of the secondary battery pack, and this current value information is output to the control unit 804. The control unit 807 has basically the same function as the control unit 704 described in FIG. 7 except for the on / off control of the overdischarge protection element 808 and the overcharge protection element 809, and is a secondary battery that is a detected secondary battery. Detect the internal resistance of the pack.

  The internal resistance detection device represented by the configuration shown in FIG. 7 can also be built in the charger, so that the internal resistance information of the detected secondary battery can be displayed or output to the outside as information. it can. Furthermore, it is possible to incorporate an internal resistance detection device represented by the configuration shown in FIG. 7 in a device main body using a secondary battery. Equipment that uses a secondary battery as a power source can estimate the internal resistance value of the secondary battery and the rate of decrease in storage capacity, so that the equipment can operate even if the performance of the secondary battery deteriorates over time. It becomes possible to predict the time accurately. Examples of devices that can maximize performance by adding the secondary battery internal resistance detection device of the present invention include portable devices such as mobile phones, portable terminals, computers, video cameras, and digital cameras, electric vehicles, and hybrid types. Vehicles that use a secondary battery such as an automobile as a power source. The function of the secondary battery internal information detection device of the present invention is enhanced to enhance the function. Other devices and systems other than the above examples include a secondary battery for inspecting whether the manufactured battery to be detected is a good product or a defective product. Examples include inspection equipment.

  In addition, it is possible to provide versatility by inputting information corresponding to different types of batteries as necessary to the storage means of the secondary battery internal resistance detection device of the present invention. become. In addition, by providing means for selecting the type of the secondary battery to be detected that is suitable for this apparatus, it is possible to select a corresponding normal secondary battery. As the means for selecting the type of the secondary battery to be detected, for example, switch input, input using a wired or wireless electric signal, optical signal, or the like can be used. Accordingly, if the battery adopts the constant current-constant voltage charging method, it is the same type of detected secondary battery and the type is different, or the type of the detected secondary battery is a lithium (ion) battery, Different cases such as a nickel-hydrogen battery, a nickel-cadmium battery, and a lead storage battery can be accommodated.

[Internal resistance detection program for secondary battery to be detected]
The internal resistance detection program of the present invention is a program in which the detection method of the present invention represented by the flowchart of FIG. 1 or FIG. 2 described above is programmed, and a constant voltage charging mode for an increase or decrease in internal resistance or internal resistance. Including data related to the amount of electricity charged. Input the program based on the detection method of the present invention, the relational data of the charge electricity amount in the constant voltage charge mode with respect to the increase / decrease of the internal resistance, to the control unit of the device body, and have the detection function of the present invention Is possible. For example, a portable personal computer connected to a secondary battery generally has a main control unit that mainly controls the operation of the main body and a sub-control unit that mainly controls communication with peripheral devices. In many cases, the unit monitors current and / or voltage information from a secondary battery as a power supply. Input to the sub-control unit or main control unit of the device that acquires the monitoring information the program of the detection method of the present invention and the relationship between the charge amount in the constant voltage charge mode and the required internal resistance or the increase / decrease of the internal resistance. Thus, the function of the detection device of the present invention can be provided in the device main body, the internal resistance information of the detected battery can be detected, and the power management accuracy of the device can be improved. This makes it possible to maximize the stored energy of the secondary battery to be used and maximize the performance of the device.

[Memory media containing the internal resistance detection program of the secondary battery to be detected]
The memory medium of the present invention is a program in which the detection method of the present invention represented by the flowchart of FIG. 1 or FIG. 2 described above is programmed, charging in a constant voltage charging mode with respect to an increase or decrease in internal resistance or internal resistance. It stores data related to the amount of electricity. Further, a calculation program for calculating the battery storage capacity reduction rate D and data to be referred to may be stored in the memory medium of the present invention. The memory medium of the present invention is used for a device using a secondary battery as a power source, which has a function of monitoring the state of charge of the battery and detecting the internal resistance of the detected secondary battery by connecting the memory medium. Can do. Typical examples of such devices include a charger, a video camera, a digital camera, a mobile phone, a portable terminal (Personal Digital Assistant), and an electric vehicle. By using the memory medium of the present invention, even if the type and type of the secondary battery (secondary battery to be detected) change, it is easy to prepare the memory medium corresponding to the change. Thus, the internal resistance of the secondary battery can be accurately detected.

[Example of obtaining discharge amount correction coefficient data at internal temperature T and discharge current I]
In the secondary battery, the internal resistance changes depending on the battery temperature and the discharge current value, and the amount of stored electricity that can be discharged changes. For this reason, as described above, even if internal information about the internal resistance and the storage capacity reduction rate of the secondary battery is obtained by the present invention, it is possible to accurately determine the operable time of the equipment that uses the secondary battery as a power source. It cannot be predicted.
Therefore, it is preferable to obtain discharge amount correction coefficient data at the temperature T and the discharge current I with respect to the internal resistance, in order to more accurately predict the operable time of the device using the battery as a power source.

Now, the internal resistance of the normal secondary battery at the temperature T ₀ (25 ° C. or room temperature) is R ₁ , and the internal resistance value of the detected secondary battery is R ′ = R ₁ by the predictive detection method of the present invention. If it is estimated that + r _s, and the discharge amount correction coefficient f_T _{, I} (R) determined by the internal resistance R at the temperature T and the discharge current I of the secondary battery, the normal resistance is R ₁ The secondary battery has a total discharge amount of C _d = C _N × f_T _{, I} (R ₁ ), and the total discharge amount of the detected secondary battery having a storage capacity reduction coefficient of D is C _d ′ = D × C _N × f_T _{, I} (R ′), where i is the average current consumption of the device using the detected secondary battery as a power source, p is the average power consumption, and i is the discharge current value. When the average discharge voltage of a normal secondary battery is Vm and the average discharge voltage of the detected secondary battery is Vm ′, the operation time h of the device is expressed by the equation h = Cd ′ / i or h = (Vm ′ × Cd ') / p, where Vm' = Vm-ix (R -R ₁ ) = Vm-ixr _s ,

In the present invention, an example of a procedure for obtaining discharge amount correction coefficient data at a temperature T and a discharge current I of a detected secondary battery having a storage capacity C _N will be described.
In the case of a secondary battery in which the storage capacity is not reduced and only the internal resistance is increased, a resistor is connected in series with the secondary battery in order to know how the discharge amount characteristic at temperature T and discharge current I changes. r _s was connected to increase the internal resistance in a pseudo manner, and after the constant current-constant voltage charging operation, the amount of discharge electricity at the temperature T and the discharge current I was observed. Next, constant current charging was performed, and the internal resistance when a predetermined voltage was reached was measured.

FIG. 9 is a circuit diagram in which a resistor r _s is connected to a normal secondary battery having an internal resistance R ₁ and connected to a charge / discharge device. In FIG. 9, when a commercially available lithium ion secondary battery having a diameter of 18 mm and a height of 65 mm and a nominal capacity of 1680 mAh is used as the normal secondary battery and the resistor r _s is not connected, the resistance value is 27 mΩ, When a resistor r _{s of} 39 mΩ, 62 mΩ, 91 mΩ, 110 mΩ, and 150 mΩ is connected, 1.7 A constant current charging is performed, and when the charging voltage reaches 4.2 V, 4.2 V constant voltage is continued. After charging until the charging current in the constant voltage charging mode drops to 0.1A, measure the amount of discharge until the battery voltage reaches 3.0V at a temperature of 25 ° C and a discharge current of 1.7A. did. Continuous charge of 1.7 A is carried out continuously, and the open circuit voltage at the time when the charging voltage reaches 4.2 V is the relational data on the amount of charge in the constant voltage charging mode with respect to the increase or decrease of the internal resistance or internal resistance. The measurement was performed in the same procedure as in the acquisition example, and the simulated internal resistance (calculated R) was calculated from the above-described equation (2).
The results obtained above are summarized in Table 2.

FIG. 14 shows the relationship between the internal resistance and the ratio of the amount of discharged electricity to the nominal capacity of 1680 mAh until the battery voltage reaches 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A, as shown in Table 2. Here, the discharge amount correction coefficient f — _{25 ° C., 1.7 A,} which is the relationship of the ratio of the amount of discharged electricity to the nominal capacity until the battery voltage reaches 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A with respect to the internal resistance R As an example, it is assumed that (R) can be expressed as a function of the internal resistance R as shown in the following equation (6).
f_ _{25 ℃, 1.7A} (R) = G _n × R ⁿ + G _n-1 × R ^n-1 + ・ ・ ・ + G ₁ × R ¹ + G ₀ × R ⁰ ---- (6)
In Expression (6), G _n to G ₀ are constants that vary depending on the type, model, nominal capacity, and the like of the secondary battery.

In this example, assuming that the discharge amount correction coefficient is expressed by a third order polynomial of internal resistance R (mΩ), a commercially available lithium ion secondary battery having a diameter of 18 mm and a height of 65 mm and a nominal capacity of 1680 mAh is as follows. Based on the acquired basic data, from the curve fitting in FIG. 14, the relationship between the internal resistance R and the ratio of the amount of discharged electricity to the nominal capacity until the battery voltage reaches 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A A functional expression of the discharge amount correction coefficient is calculated. The calculated function formula is as follows.
f_ _{25 ℃, 1.7A} (R) = −0.0000000068 × R ³ + 0.0000041892 × R ² −0.0010928023 × R
+1.0698074090 ---- (7)
Even if the measurement data is the same type and the same type of battery, there is an individual difference. Therefore, it is preferable to use data obtained by averaging data obtained from a plurality of batteries.
In this example, the function expression of _{f_25 ° C., 1.7A} (R) is represented by a third order polynomial of the internal resistance R, but in the present invention, it is limited to the order of these polynomials. is not. Further, these functional expressions are not limited to n-order polynomials. Furthermore, in this example, the discharge amount correction coefficient data at the temperature T and the discharge current I with respect to the internal resistance has been described as a function expression of an approximate curve, but this relationship may be expressed as a data table. Therefore, if the correction coefficient data, the internal resistance value estimated by the present invention, the battery temperature T as the discharge environment, and the discharge current I are known, the amount of electricity that can be discharged from the fully charged battery can be calculated. become.

As described above, the relationship between the internal resistance or the amount of charge in the constant voltage charging mode with respect to the increase or decrease of the internal resistance, the temperature T with respect to the internal resistance, and the discharge amount correction coefficient at the discharge current I are each a normal secondary battery. It is not limited to the function formula obtained from the data measured in advance. For example, obtain as a functional expression obtained by simulation based on information on the composition, thickness, density, dimensions, etc. of the positive electrode and negative electrode of a normal secondary battery and information on the electrolyte and battery structure, etc. Is also possible. In addition, it can be obtained as an empirical formula from a large number of measured data from secondary batteries in various deterioration mode states, but it is necessary to have a secondary battery in various deterioration mode states, A great deal of labor is required because analysis is necessary.
In the present invention, the relationship between the internal resistance or the increase / decrease in the internal resistance and the amount of charge in the constant voltage charging mode, the temperature T against the internal resistance, the discharge amount correction coefficient data at the discharge current I, the internal resistance is R ₁ It is more preferable that a normal secondary battery and a resistor r _s having various resistance values on the same order as R ₁ are connected in series to obtain each of them because it is simple and high accuracy can be obtained.
The present invention will be described in more detail based on the following examples, but the present invention is not limited to these examples.

In this example, as a reference, as described above, the relationship between the internal resistance or the increase / decrease in the internal resistance and the relationship between the amount of charge electricity in the constant voltage charging mode is 18 mm in diameter and 65 mm in diameter, and the nominal capacity is 1680 mAh. A constant current-constant voltage charge is performed using a commercially available lithium ion secondary battery and a secondary battery of the same type and the same type, which is considered not to decrease in storage capacity, and the internal resistance of the secondary battery is shown in the flowchart of FIG. Then, the actual internal resistance was obtained and compared to verify the effectiveness of the present invention. That is, the detected secondary battery is charged with a constant current of 1.7 A. When the charging voltage reaches 4.2 V, the secondary battery is continuously charged with a constant voltage of 4.2 V, and the charging current in the constant voltage charging mode is The amount of electricity charged in the constant voltage charging mode when charging was terminated when the current decreased to 0.1 A was determined. Next, the internal resistance R (mΩ) with respect to the charge electricity quantity Q (mAh) in the constant voltage charge mode, which is an example of relational data of the charge quantity in the constant voltage charge mode with respect to the internal resistance or the increase / decrease of the internal resistance, The internal resistance of the battery to be detected was estimated by substituting the obtained charge electricity amount in the constant voltage charging mode into the above-described function equation (4). Next, after discharging the secondary battery to be detected with a constant current of 0.17 A to a final voltage of 3.0 V, the battery is charged with a constant current of 1.7 A and terminated when the charging voltage reaches 4.2 V, After a predetermined time, the open circuit voltage was measured, and the internal resistance was calculated from the above equation (1).
The results obtained above are summarized in Table 3. In Table 3, the CV charge amount is the charge electricity amount in the constant voltage charge mode, the detection R is the internal resistance value (predicted value) calculated by the method of the present invention, and the open circuit voltage is the predetermined time after the end of charge. The calculated R indicates the internal resistance value calculated from the open circuit voltage Voc obtained as Vc = 4.7 and I = 1.7A in the equation (1).

From the results shown in Table 3, the error between the detected value of the internal resistance of the detected secondary battery (predicted value according to the present invention) and the calculated value from the open circuit voltage is calculated by the following equation:
｜ 145.4−144.1 ｜ /144.1×100=0.9 (%) ---- (8)
The error was 0.9%.
If the internal resistance detection method of the present invention is used, it is possible to obtain a specific operation during constant current-constant voltage charging, or from a measured value of charge electricity in the constant voltage charging mode without requiring a special time for detection. It was found that the internal resistance can be detected simply and accurately.

  In this example, the relationship between the internal resistance or the increase / decrease in the internal resistance described above and the relationship between the amount of charge electricity in the constant voltage charging mode is 18 mm in diameter and 65 mm in diameter and the nominal capacity is 1680 mAh. For a secondary battery of the same type and the same type as the secondary battery, charge / discharge is repeated 160 times in advance, cycle deterioration is performed, constant current-constant voltage charge is performed, and detection is performed according to the flowchart of FIG. Obtained and compared to verify the effectiveness of the present invention.

That is, the detected secondary battery is charged with a constant current of 1.7 A. When the charging voltage reaches 4.2 V, the secondary battery is continuously charged with a constant voltage of 4.2 V, and the charging current in the constant voltage charging mode is The amount of electricity charged in the constant voltage charging mode when charging was terminated when the current decreased to 0.1 A was determined. Next, the obtained charge electricity amount is multiplied by 1 / D (the storage capacity decrease rate of the detected secondary battery is assumed to be D), and then the charge electricity amount in the constant voltage charge mode with respect to the increase or decrease in internal resistance or internal resistance In the function equation (4) of the internal resistance R (mΩ) with respect to the charge electricity amount Q (mAh) in the constant voltage charge mode, which is an example of the relationship data, the charge electricity amount in the constant voltage charge mode obtained is A value multiplied by 1 / D was substituted to detect the internal resistance of the secondary battery to be detected. Next, after discharging the secondary battery to be detected with a constant current of 0.17 A to a final voltage of 3.0 V, the battery is charged with a constant current of 1.7 A and terminated when the charging voltage reaches 4.2 V, After a predetermined time, the open circuit voltage was measured, and the internal resistance was calculated from the above equation (1).
The results obtained above are summarized in Table 4.

From Table 4, the error between the detected value of the internal resistance of the detected secondary battery (predicted value according to the present invention) and the calculated value from the open circuit voltage is calculated by the following equation:
｜ 203.6−205.9 ｜ /205.9×100＝1.1 （％） ---- (9)
The error was 1.1%.
Here, the storage capacity decrease rate D of the detected battery in Table 4 is a predetermined current value from the time when the constant secondary battery is switched from the constant current 1.7 A charge mode to the constant voltage 4.2 V charge mode. Measure the time t _M 'to reach 0.85A and the amount of charge Q _CV ' in the constant voltage charging mode, and measure t _M and Q _CV in advance for the corresponding normal secondary batteries. , A value calculated from the above equation (5). The results obtained above are summarized in Table 5.

In Equation (2) described above, since I ₀ is a charging current value 1.7 A in the constant current charging mode, the following equation D = (0.6231−1.7 × 0.308) / (0.4038−1.7 × 0.170) − -- (Ten)
From this, the storage capacity decrease rate D of the battery to be detected was calculated.
Next, how much is calculated when the internal resistance is predicted and detected without using the method of the present invention and when the open circuit voltage of the battery is measured during the charging operation and the internal resistance is calculated from the equation (1)? The effectiveness of the method of the present invention was confirmed by comparing whether time was required.
FIG. 15 shows a battery voltage with respect to an elapsed time of 120 minutes after the end of charging when charging is performed at a constant current of 1.7 A and the charging voltage reaches 4.2 V (the charging current is zero. FIG. 2 is a diagram showing an open circuit voltage of a battery. It can be seen that the battery voltage gradually decreases and converges to a voltage of 3.85 V after 90 minutes.

FIG. 16 is a diagram in which the internal resistance values obtained by introducing the voltage value on the vertical axis in FIG. 15 into Voc ₀ in the above-described equation (1) and V _d = 4.2 V and I = 1.7 A are plotted. This indicates a value when the voltage value at each time is regarded as an open circuit voltage and the internal resistance of the detected secondary battery is calculated. Assuming that 3.85V after 90 minutes is a sufficiently converged open circuit voltage value, 3.85V is a correct open circuit voltage value, and 205.9 mΩ calculated by that value is considered to be a true internal resistance R. .

FIG. 17 shows the following equation: | R ₀ −R | / R × 100 (11) where R ₀ is the calculated internal resistance value (calculated from the battery voltage with respect to time) on the vertical axis in FIG.
It is the figure which performed calculation of and showed the calculation result on the vertical axis | shaft. This is the true internal resistance value when charging is stopped when the constant voltage reaches 4.2 V, the voltage value over time is regarded as an open circuit voltage, and the internal resistance of the detected secondary battery is calculated. The error with R is shown. The error of 1.1% in the present detection method obtained from the equation (9) was found to be as accurate as providing a pause time of 80 minutes or more in FIG. This means that if the method for predicting the internal resistance of the present invention is employed, the time of 80 minutes for measuring the open circuit voltage for calculating the internal resistance is insoluble.
By using the internal resistance detection method of the present invention, even if the secondary battery to be detected is cycle-degraded, a specific operation during constant current-constant voltage charging and a special time for detection are not required. From the measured value of charge electricity in the constant voltage charge mode, it was found that the internal resistance can be detected easily and accurately.

  In this example, the relationship between the internal resistance or the increase / decrease in the internal resistance described above and the relationship between the amount of charge electricity in the constant voltage charging mode is 18 mm in diameter and 65 mm in diameter and the nominal capacity is 1680 mAh. After secondary batteries and secondary batteries of the same type and the same type are stored in a high temperature atmosphere at 80 ° C. for 10 days in advance, and then subjected to constant current-constant voltage charging, after detection according to the flowchart of FIG. The actual internal resistance was obtained and compared to verify the effectiveness of the present invention.

That is, a constant current charge of 1.7 A is performed on the deteriorated detected secondary battery, and when the charging voltage reaches 4.2 V, the secondary battery is continuously charged with a constant voltage of 4.2 V, and in the constant voltage charging mode. The amount of charge electricity in the constant voltage charge mode when charging was terminated when the charging current decreased to 0.1 A was determined. Next, the obtained charge electricity amount is multiplied by 1 / D (the storage capacity decrease rate of the detected secondary battery is assumed to be D), and then the charge electricity amount in the constant voltage charge mode with respect to the increase or decrease in internal resistance or internal resistance In the function equation (4) of the internal resistance R (mΩ) with respect to the charge electricity quantity Q (mAh) in the constant voltage charge mode, which is an example of the relationship data of A value obtained by multiplying the amount by 1 / D was substituted to predict and detect the internal resistance of the secondary battery to be detected. Next, after discharging the secondary battery to be detected with a constant current of 0.17 A to a final voltage of 3.0 V, the battery is charged with a constant current of 1.7 A and terminated when the charging voltage reaches 4.2 V, After a predetermined time, the open circuit voltage was measured, and the internal resistance was calculated from the above equation (1).
The results obtained above are summarized in Table 6. In Table 6, the CV charge amount Qcv ′ is the charge electricity amount in the constant voltage charge mode, the detection R is the internal resistance value (predicted value) calculated by the method of the present invention, and the open circuit voltage is after the end of charge. The calculated R represents the open circuit voltage at the time when a predetermined time has elapsed, and the internal resistance value calculated from the open circuit voltage Voc obtained as Vc = 4.7 and I = 1.7 A in equation (1).

From the results shown in Table 6, the error between the detected value of the internal resistance of the detected secondary battery and the calculated value is calculated by the following equation:
｜ 305.8−311.8 ｜ ／311.8×100＝1.9 （％） ---- (12)
The error was 1.9%.
Here, the storage capacity decrease rate D of the detected secondary battery in Table 6 is predetermined from the time when the detected secondary battery is switched from the constant current 1.7 A charge mode to the constant voltage 4.2 V charge mode. Measure the time t _M 'until the current value reaches 0.85A and the amount of charge Q _CV ' in the constant voltage charging mode, and measure t _M and Q _CV in advance for the corresponding normal secondary batteries. It is a value calculated from the above equation (5).
The results obtained above are summarized in Table 7.

In the above equation (2), since I ₀ is a charging current value 1.7 A in the constant current charging mode, the following equation D = (1.1705−1.7 × 0.637) / (0.4038−1.7 × 0.170) ---- (13)
From this, the storage capacity decrease rate D of the detected secondary battery was calculated.
Further, according to FIG. 17, it was found that the error of 1.9% in the detection method of the present invention has the same accuracy as the internal resistance value obtained from the open circuit voltage after 45.
With the internal resistance detection method of the present invention, even when the secondary battery to be detected has deteriorated due to long-term storage in a high-temperature environment, a special operation or constant detection during constant current-constant voltage charging is possible. It was found that the internal resistance can be detected easily and accurately from the measured value of the amount of charge in the constant voltage charging mode without requiring time.

In this embodiment, the relational data of the charge amount in the constant voltage charge mode with respect to the internal resistance or the increase / decrease of the internal resistance described above, and the discharge amount correction coefficient at the temperature T and discharge current I for the internal resistance described above. A MOSFET with a parasitic diode (FY8ABJ-03; manufactured by Mitsubishi Electric Corporation) is used in the charge / discharge path of a commercially available lithium ion secondary battery having a diameter of 18 mm, a height of 65 mm, and a nominal capacity of 1680 mAh. It is considered that there is no reduction in the storage capacity, with an overcharge protection element and an overdischarge protection element made up of)) and a resistor (WSL-2512 (20 mΩ); manufactured by Vishay) for detecting the charge / discharge current. The secondary battery pack is charged with a constant current and a constant voltage and detected according to the flowchart of FIG. 1, and then the actual internal resistance is obtained and compared to verify the effectiveness of the present invention. It was. Also, from the detected internal resistance value, the ratio of the amount of discharged electricity to the nominal capacity until the battery voltage reaches 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A is estimated, and the dischargeable time is predicted from the estimated value After that, the actual discharge time was measured to verify the effectiveness of the present invention.

That is, the detected secondary battery is charged with a constant current of 1.7 A. When the charging voltage reaches 4.2 V, the secondary battery is continuously charged with a constant voltage of 4.2 V, and the charging current in the constant voltage charging mode is The amount of electricity charged in the constant voltage charging mode when charging was terminated when the current decreased to 0.1 A was determined. Next, the internal resistance R (mΩ) with respect to the charge electricity quantity Q (mAh) in the constant voltage charge mode, which is an example of relational data of the charge quantity in the constant voltage charge mode with respect to the internal resistance or the increase / decrease of the internal resistance, The internal resistance of the secondary battery to be detected was detected by substituting the obtained charge electricity amount in the constant voltage charging mode into the above-described function formula (4).
In addition, in the example of the discharge amount correction coefficient data, which is the relationship of the ratio of the amount of discharged electricity to the nominal capacity until the battery voltage reaches 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A with respect to the internal resistance R (mΩ). By substituting the detected internal resistance value into a certain function equation (7) above, the amount of discharge electricity until the battery voltage reaches 3.0 V at a detected secondary battery temperature of 25 ° C. and a discharge current of 1.7 A. The ratio to the nominal capacity was estimated, and the dischargeable time was predicted from the estimated value.

Next, the detected secondary battery was discharged to a final voltage of 3.0 V at a temperature of 25 ° C. and a discharge current of 1.7 A, and the discharge time from the start of discharge to the final voltage of 3.0 V was measured. Thereafter, constant current charging of 1.7 A was performed, and the charging was terminated when the charging voltage reached 4.2 V. After a predetermined time, the open circuit voltage was measured, and the internal resistance was calculated from the above equation (1). .
The results regarding the internal resistance obtained above are summarized in Table 8, and the results regarding the discharge time are summarized in Table 9, respectively. In Table 8, the CV charge amount is the charge electricity amount in the constant voltage charge mode, the detection R is the internal resistance value (predicted value) calculated by the method of the present invention, and the open circuit voltage is the predetermined time after the end of charge. The calculated R indicates the internal resistance value calculated from the open circuit voltage Voc obtained as Vc = 4.7 and I = 1.7A in the equation (1).

From Table 8, the error between the detected value of the internal resistance of the detected secondary battery (predicted value according to the present invention) and the calculated value calculated from the open circuit voltage is calculated by the following equation:
| 233.1−235.3 | /235.3×100=0.9 (%) ---- (14)
The error was 0.9%.
Also, from Table 9, the error between the predicted value of the discharge time until the battery voltage reaches 3.0 V at a detected secondary battery temperature of 25 ° C. and a discharge current of 1.7 A is calculated by the following equation: ,
｜ 56.7−57.1 ｜ /57.1×100=0.7 (%) ---- (15)
The error was 0.7%.
According to the internal resistance detection method of the present invention, the secondary battery to be detected is a secondary battery housed in a secondary battery pack, and the secondary battery pack includes a switching element for charging that can be controlled on and off by a control circuit. Even if at least one of the switching element for discharging and the current value detecting element for charging / discharging is interposed in the charging / discharging path, it is special for specific operation or detection during constant current-constant voltage charging. It was found that the internal resistance can be detected easily and accurately from the measured value of the amount of charge in the constant voltage charging mode without requiring time. It was also found that the dischargeable time until reaching the predetermined voltage at the temperature T and the discharge current I can be predicted with high accuracy from the predicted internal resistance value.

  As described above, as verified in Examples 1 to 4, by using the partial resistance detection method of the present invention, the internal resistance of the secondary battery to be detected can be detected with a very simple method with high accuracy. In Examples 1 to 4, one type of commercially available lithium ion secondary battery was used. However, the constant current-constant voltage charging method is not limited to the size, type, or type of the secondary battery. The present invention is applicable to any secondary battery that can adopt the above. In the first to fourth embodiments, the example in which the internal information of the single cell is detected has been described. However, the present invention is not limited to this, and according to the present invention, a plurality of cells can be connected in parallel, in series, or directly. Also in the battery pack formed by connecting in parallel, the internal information can be obtained from the data acquired in advance from the battery pack as a normal reference.

In the above, the present invention has been described with reference to various embodiments and examples. However, the scope of the present invention is not limited to these, and various modifications can be made without departing from the spirit of the present invention. It goes without saying that there is.

  According to the present invention, it is possible to detect the internal resistance of the secondary battery to be detected with high accuracy by a simple method from measurement of the amount of charge in the constant voltage charging mode in the constant current-constant voltage charging method. it can. Therefore, the performance of various devices using the secondary battery as a power source can be maximized.

These are the flowchart figures which showed an example of the internal resistance detection method of the secondary battery in this invention. These are the flowchart figures which showed the other example of the internal resistance detection method of the secondary battery in this invention. These are the figures which showed the change of the battery voltage when the charge of a constant current-constant voltage charge system and charge stop (pause) were repeated for the secondary battery. These are the figures which showed the relationship of the battery voltage with respect to the integrated charge amount obtained in FIG. 3, and the battery voltage at the time of charge suspension (= open circuit voltage). Is the relationship between the storage amount of each of the normal secondary battery and the cycle-degraded secondary battery and the open circuit voltage, and the storage amount of the cycle-degraded secondary battery is 1 / D = 1 / 0.84 times (1.19 times). ) And plotted. Is the relationship between the charging time and charging current in constant current-constant voltage charging of each of the normal secondary battery and the cycle deteriorated secondary battery, and the charge time of the cycle deteriorated battery is 1 / D = 1 / 0.84 times. It is the figure plotted by (1.19 times). These are the figures which showed the structure of the principal part of an example of the internal resistance detection apparatus which detects the internal resistance of the secondary battery of this invention. These are the figures which showed the structure of an example of the secondary battery pack which added the internal resistance detection apparatus which detects the internal resistance of the secondary battery of this invention. The internal resistance is connected a resistor r _s in series to a normal rechargeable battery which is R _I, a circuit diagram which is connected to the charging device. Is in the case of changing the resistance value of the resistor r _s of the series connection in Figure 9, the constant current - is a graph showing the charging voltage for the charging time at the time of constant voltage charging. Is in the case of changing the resistance value of the resistor r _s of the series connection in Figure 9, the constant current - is a diagram showing the charging current to charge the amount of the constant voltage charging. It is the case of no resistor r _s of the series connection in Figure 9, a constant current - when the end of charge at a constant voltage reached the point of the constant voltage charging of a battery voltage with respect to the elapsed time after the completion of charging Fig It is. These are the figures which showed an example of the relationship data of the amount of charge electricity in the constant voltage charge mode with respect to the increase / decrease in internal resistance or internal resistance. FIG. 5 is a diagram showing an example of discharge amount correction coefficient data at a temperature T and a discharge current I with respect to the internal resistance. These are the figures which showed the battery voltage with respect to the elapsed time after completion | finish of charge when it is set as completion | finish of charge at the time of constant voltage arrival in constant current-constant voltage charge of a cycle deterioration secondary battery. FIG. 16 is a diagram in which the above-described equation (1) is calculated and plotted with the voltage value on the vertical axis in FIG. 15 as Voc ₀ . FIG. 17 is a diagram in which the above equation (11) is calculated and plotted with the resistance value on the vertical axis in FIG. 16 as R ₀ .

Claims (30)

A method of detecting the internal resistance of a secondary battery to be detected, which is a constant current-constant voltage charging method (after charging starts at a constant current value I ₀ and the battery voltage reaches a predetermined voltage V _max , When charging is performed by a charging method comprising a combination of a constant current charging mode and a constant voltage charging mode in which charging is performed at a predetermined voltage V _max until the end of charging, at least the constant voltage charging mode of the detected secondary battery A step (a) of obtaining an integrated value of the amount of charge charged (charge amount in constant voltage charge mode), and a normal secondary battery corresponding to the detected secondary battery (storage of a normal battery) The internal resistance R (= R ₁ + r _s ) when the internal resistance R ₁ of the normal secondary battery is increased or decreased, or the internal resistance acquired in advance for the secondary battery whose capacity is changed and only the internal resistance is changed Increase / decrease in resistance wherein for _s charged electricity quantity in the constant voltage internal resistance and a constant voltage charging mode of the relationship (normal battery charging electric quantity Q _cv of said normal rechargeable battery in the charging mode relation R vs Q _cv, r _s vs A method for detecting the internal resistance of a secondary battery, wherein the internal resistance of the battery to be detected is predicted by performing an operation having a step (b) referring to Q _cv ).   The secondary battery to be detected is a secondary battery in a secondary battery pack. The secondary battery pack includes a control circuit, a charging switching element that can be controlled on and off by the control circuit, and a discharging switching element. 2. The method for detecting the internal resistance of the secondary battery according to claim 1, wherein at least one of the current value detection elements for charging and discharging is interposed in a charging / discharging path of the secondary battery.   When the storage capacity of the detected secondary battery is reduced to D times the storage capacity of the normal secondary battery (D is a constant of 0 <D ≦ 1 indicating a reduction rate of the storage capacity), After multiplying the charge electricity quantity in the constant voltage charge mode obtained in the step (a) by 1 / D, the normal resistance of the normal battery and the charge electricity quantity in the constant voltage charge mode described in the step (b) are calculated. 2. The method of detecting the internal resistance of a secondary battery according to claim 1, wherein an operation of referring to the relationship is performed. The storage capacity decrease rate D of the detected secondary battery is predetermined from the time when the constant current I ₀ charging mode is switched to the constant voltage V _max charging mode in the constant current-constant voltage charging of the detected secondary battery. current time t _M until the I _M when in ', charged electricity quantity in the constant voltage charging mode is Q _CV', wherein in a normal secondary battery are respectively t _M, Q _CV, equation The method of detecting the internal resistance of the secondary battery according to claim 3, wherein D = (Q _CV ′ −I ₀ × t _M ′) / (Q _CV −I ₀ × t _M ). The predetermined current value I _M is in a range of 0.4 × I ₀ ≦ I _M ≦ 0.6 × I ₀ of the charging current I ₀ in the constant current charging. Method for detecting internal resistance of secondary battery. 6. The secondary battery according to claim 5, wherein the predetermined current value I _M is ½ of a charging current I ₀ in the constant current charging, that is, I _M = 0.5 × I _0. Internal resistance detection method.   The relationship between the internal resistance of the normal battery and the amount of charge in the constant voltage charging mode described in the step (b) is the actual data acquired in advance for the normal secondary battery, the relationship obtained from the actual data 2. The method for detecting the internal resistance of a secondary battery according to claim 1, wherein the characteristic is selected from an equation and a relational equation obtained from a computer simulation. Wherein the quantity of charged electricity of the relationship in the internal resistance and a constant voltage charging mode of the normal rechargeable battery, the internal resistance is connected various resistance value resistor (r _s) in series with the normal rechargeable battery is R _1, A normal secondary battery having a resistance value R (= R ₁ + r _s ) increased by simulating the internal resistance is charged by the constant current-constant voltage charging method, and the internal resistance in the constant voltage charging mode is 8. The relationship obtained by an operation for measuring a charge amount of a normal secondary battery connected with a resistor of various resistance values imitating an increased detected battery, according to claim 7. A method for detecting the internal resistance of a secondary battery.   9. The method for detecting internal resistance of a secondary battery according to claim 8, wherein a resistance value of the resistor connected in series is the same as or an order of magnitude different from the internal resistance of the normal secondary battery. In the relationship between the internal resistance of the normal battery and the amount of charge in the constant voltage charging mode, the internal resistance value R (= R ₁ + r _s ) is the constant current-constant voltage charging method (with a constant current value I ₀₎ . The charging operation is performed by a charging operation according to a constant current charging mode and a constant voltage charging mode in which charging is started and charging is performed at a predetermined voltage V _max until charging is completed after the battery voltage reaches the predetermined voltage V _max. The open circuit voltage Voc at the time when it reaches _max is measured, and the resistance value R is calculated from the V _max , Voc and I ₀ and the relational expression R = (V _max −Voc) / I ₀ The method for detecting the internal resistance of the secondary battery according to claim 8. 2. The method for detecting internal resistance of a secondary battery according to claim 1, wherein the end point of the constant voltage charging is a point in time when one of the following three states is reached.
(I) When the charging current in the constant voltage charging mode becomes a predetermined current value I _min or less,
(Ii) When a predetermined time t _n has elapsed after the charging current in the constant voltage charging mode has reached a predetermined current value In, and (iii) When a predetermined time t _f has elapsed since the start of charging. A method for predicting an operating time of a device that uses a detected battery as a power source from an internal resistance of the detected secondary battery estimated by the detection method according to claim 1, wherein the capacity reduction corresponding to the detected battery is reduced. When the internal resistance value is R (= R ₁ + r _s ) at the temperature T ₀ of the normal secondary battery having no storage capacity C _N , the total discharge amount C _d at the temperature T and the discharge current I is C _d = C _N × f_T _{, I} (R) (f_T _{, I} (R) is a discharge amount correction coefficient determined by the internal resistance R at the temperature T and the discharge current I), and the internal resistance is R ₁ The total discharge amount of the normal secondary battery is C _d = C _N × f_T _{, I} (R ₁ ), the storage capacity is not reduced, and the internal resistance is R (= R ₁ + r _s ). the total discharge amount of the next cell _{C d '= C N × f_} T, I (R), in each represented, the object to be detected The average discharge voltage of a normal secondary battery whose average current consumption is i, the average power consumption is p, and the discharge current value is i is Vm and the average discharge of the detected secondary battery When the voltage is Vm ′, the operating time h of the device is expressed as h = C _d ′ / i or h = (Vm ′ × C _d ′) / p, where Vm ′ = Vm−i x (R−R _{1) = Vm-i x r} s, in a calculation method of predicting the operation time of the device to be powered by a rechargeable battery, characterized by. The discharge amount correction coefficient f_T _{, I} (R) determined by the internal resistance R at the temperature T and the discharge current I is obtained from the actual measurement data and the actual measurement data of the discharge amount correction coefficient acquired in advance for the normal secondary battery. 13. The method for predicting the operating time of a device using a secondary battery as a power source according to claim 12, wherein the method is selected from the obtained relational expression and the relational expression obtained from computer simulation. . For the normal secondary battery in which the discharge amount correction coefficient f_T _{, I} (R) acquired in advance for the normal secondary battery has the temperature T ₀ , the internal resistance is R ₁ , and the storage capacity is C _d , A battery having a resistance value (r _s ) connected in series, and a battery in which the internal resistance value of the secondary battery is increased to R (= R ₁ + r _s ) in a simulated manner is applied to a constant current-constant voltage charging operation ( after starting to battery voltage charging at a constant current value I ₀ reaches a predetermined voltage V _max, after up to end of charging performed until the charging terminating charging at a predetermined voltage V _max), the temperature T and the discharging current discharged until a predetermined voltage V _min with I, connect a resistor of the various resistance simulatively measuring each of the discharge electric quantity C _d of the normal rechargeable battery having an internal resistance value R, 2. Calculated from the formula C _d / C _N = f_T _{, I} (R) A method for predicting an operation time of a device that uses the secondary battery as a power source according to 3.   The method of claim 14, wherein a resistance value of the resistors connected in series is equal to or an order of magnitude higher than an internal resistance of the normal secondary battery. A resistor having various resistance values (r _s ) is connected in series to a normal secondary battery having the internal resistance value R (= R ₁ + r _s ) having an internal resistance R ₁ at the temperature T ₀ . A battery having an internal resistance value of resistance value R (= R ₁ + r _s ) is charged with a constant current-constant voltage charging operation (a constant current value I ₀ is started and the battery voltage reaches a predetermined voltage V _max . in the rear performs predetermined charge voltage _{V max} until the charging ends), measures the open-circuit voltage Voc at the time of reaching a predetermined voltage _{V max,} the _V max, Voc, and _{I 0} the equation R = ( The method according to claim 14, wherein the resistance value R is calculated from V _max −Voc) / I ₀ . The storage capacity of the detected secondary battery whose internal resistance is R (= R ₁ + r _s ) decreases to D times the storage capacity of the normal secondary battery (D is a constant, 0 <D ≦ 1) If you are, apparatus all the discharge amount of the object to be detected secondary battery _{C d '= D × C N} × f_ T, I (R), in expressed, using the detection target secondary battery to a power source When the average discharge voltage of a normal secondary battery having an average current consumption of i, an average power consumption of p, and a discharge current value of i is Vm, and the average discharge voltage of the detected secondary battery is Vm ′, the operating time h of the device, the formula h = Cd '/ i or h = (Vm' × Cd ' ) / p, where _{Vm' = Vm -i x (R} -R 1) = Vm-i x r s in, 13. A method for predicting the operating time of a device according to claim 12, characterized in that it is calculated. When it is assumed that the storage capacity of the detected secondary battery is reduced to D times the storage capacity of the normal secondary battery (D is a constant, 0 <D ≦ 1), the detected secondary battery In the constant current-constant voltage charging of the battery, the time from the switching from the charging mode of the constant current I _{0 to} the charging mode of the constant voltage V _max to the predetermined current value I _M is t _M ′, the constant voltage charging mode 'in, when the in normal rechargeable battery internal resistance _{R 1} are each _{t M, Q CV,} equation D = _{(Q CV'} charged electricity quantity _{Q CV} in -I ₀ × _{t M} ') The method for predicting the operation time of the device according to claim 17, wherein the storage capacity decrease rate D is calculated from / (Q _CV −I ₀ × t _M ). The predetermined current value I _M is in a range of 0.4 × I ₀ ≦ I _M ≦ 0.6 × I ₀ of the charging current I ₀ in the constant current charging. A method of predicting the operating time of equipment. The operation of the apparatus according to claim 19, wherein the predetermined current value I _M is ½ of a charging current I ₀ in the constant current charging, that is, I _M = 0.5 × I _0. How to predict time. An apparatus for detecting an internal resistance of a secondary battery to be detected, wherein at least means for detecting a voltage of the secondary battery to be detected, means for detecting a current flowing through the secondary battery to be detected, constant current-constant (after the starts charging with a constant current value I ₀ battery voltage reaches a predetermined voltage V _max, the charging performed until the charging terminating charging at a predetermined voltage V _max) voltage charging said at constant voltage charging mode at the Means for obtaining the amount of charge of the detection secondary battery, the relationship of the amount of charge in the voltage charging mode of constant current-constant voltage charging with respect to the internal resistance of the secondary battery corresponding to the detected secondary battery without capacity deterioration. Means for storing, and means for detecting the internal resistance of the secondary battery to be detected from the amount of charge in the constant voltage charging mode with reference to the information of the storage means. Detection device. The means for detecting the internal resistance of the detected secondary battery is at least an integrated value of the amount of charge charged during the constant voltage charge mode of the detected secondary battery (the amount of charge charged in the constant voltage charge mode) ) determining the (a), and its internal resistance when said is previously obtained for a normal rechargeable battery corresponding to the detected secondary battery, said increase or decrease the internal resistance R ₁ of the normal rechargeable battery R (= R 1 + _{r s)} or the charged electricity of the normal rechargeable battery in the constant voltage charging mode (battery change only the internal resistance maintaining the storage capacity of the normal rechargeable battery) for increment or decrement r _s of the internal resistance the amount _Q relationship _cv (internal resistance and charging electricity quantity in the constant voltage charging mode of the normal rechargeable battery relationship _{R vs Q cv, r s vs} Q cv) comprising the step (b) to refer to, based on the detection method Calculate the internal resistance The internal resistance detecting device of the secondary battery according to claim 21, characterized in that an arithmetic unit to guess.   The internal resistance detection device for a secondary battery according to claim 21, wherein the detected secondary battery is accommodated in a secondary battery pack.   In the secondary battery pack, at least one of a control circuit, a charging switching element that can be controlled on and off by the control circuit, a discharging switching element, and a charge / discharge current value detection element is a charging / discharging path of the secondary battery. The internal resistance detection device for a secondary battery according to claim 23, which is interposed in the battery.   The internal resistance detection device for a secondary battery according to claim 24, wherein an internal resistance detection device is accommodated in the secondary battery pack.   When the storage capacity of the detected secondary battery is reduced to D times the storage capacity of the normal battery (D is a constant 0 <D ≦ 1), the detected secondary battery in the constant voltage charging mode is used. And further comprising means for detecting the internal resistance of the secondary battery to be detected from the charge quantity in the constant voltage charge mode with reference to the information in the storage means after multiplying the charge quantity of the secondary battery by 1 / D. The internal resistance detection device for a secondary battery according to claim 21.   A machine or apparatus to which the apparatus according to claim 21 is added.   Inspection device that inspects whether the manufactured secondary battery is good or defective, charger for charging secondary battery, mobile device of mobile phone / mobile terminal / portable computer, automobile, motorcycle, ship, aircraft, 28. The machine or device of claim 27, wherein the machine or device is selected from a spacecraft moving body.   A program for detecting the internal resistance of a secondary battery to be detected, wherein the detection method according to claim 1 is incorporated.   30. A storage medium storing the internal resistance detection program for a secondary battery according to claim 29.