JPH07239373A - Calculator for residual capacity of battery - Google Patents

Abstract

PURPOSE:To obtain a calculator for obtaining the residual capacity of a battery which facilitates the adjustment, has a smaller scale and can determine the residual capacity accurately even when a power failure occurs or the battery is left alone. CONSTITUTION:This apparatus is provided with a history memory means to store a service history of a battery up to that time, a charging/discharging state detection means 6 to check to see whether the battery is in the charged state or discharged state, a timepiece 7 to measure the time of the state of being charged or discharged and a charging function table 10 to calculate a charged value from the time of being charged. A charging value corresponding to new charging time is added to a charged value before the charging obtained from the above history from a function from the table to obtain the newest charging value. Moreover, a discharge function table 12 is provided to calculate discharging capacity from a load value and the discharging time in the discharging state, and in the time of recharging after the discharging, a correction charging time is estimated utilizing the discharge function table 12 from the residual capacity stored in the history memory means to be added to the recharging time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to estimation of a battery remaining capacity of an uninterruptible power supply unit added to a power supply of electronic equipment.

[0002]

2. Description of the Related Art FIG. 6 shows a functional block diagram of a conventional battery control system disclosed in, for example, Japanese Utility Model Publication No. 60-6767, in which 1 is a battery and 2 is a discharge amount of the battery. Is a remaining capacity meter for detecting the time, 3 is a time storage unit for storing battery usage time, 4 is a logarithmic amplifier, and 5 is a subtraction circuit. The subtraction circuit subtracts the output of the logarithmic amplifier from the output of the remaining capacity meter and outputs the corrected remaining capacity of the battery.

Next, the operation of the control system having the above configuration will be described. The remaining capacity meter 2 is a circuit designed to detect a current and a terminal voltage when the battery is discharged and output a voltage corresponding to the remaining capacity of the battery from the detected values. on the other hand,
Generally, a battery has a significantly reduced chargeable capacity in about 3 years and reaches the end of its life. However, as the battery approaches its life, the chargeable capacity thereof decreases with time of use. In this conventional example, in order to take this characteristic into consideration, the battery storage time is stored by the time storage unit, and the output is logarithmically amplified to obtain a result approximate to the battery life curve, which is subtracted from the remaining capacity of the battery. It has been corrected.

Further, in Japanese Patent Laid-Open No. 3-163375, in the column of the prior art, the input / output current value of the secondary battery is integrated and added / subtracted to / from the remaining capacity value displayed on the instrument to re-calculate the remaining capacity appropriately. There is a disclosure of a system for displaying, and in Japanese Patent Laid-Open No. 1-313782, in the section of means for solving the problem, the actual use time after completion of charging is integrated and the discharge current during actual use of the battery is integrated. There is disclosed a method of calculating the remaining capacity of the battery by subtracting the discharge current integrated value from the battery capacity when the battery is completely charged.

[0005]

Since the conventional battery control system is constructed as described above, it has the following problems. (1) Since it is necessary to use a remaining capacity meter and a logarithmic amplifier that match the target battery characteristics, adjustment is difficult, and the device is complicated and expensive. In addition, the estimation of the remaining capacity is inaccurate in the method of integrating the charge / discharge current. (2) It is not possible to correctly obtain the remaining capacity when a power failure occurs again during charging after recovery from a power failure. (3) If there is a period in which the battery is left uncharged or discharged, the remaining capacity cannot be calculated correctly. (4) The battery load is always full load operation, and sufficient backup becomes impossible when the battery capacity is insufficient or the charging time is insufficient.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain a battery remaining capacity calculating device shown below. (1) Adjustment is easy, and a small-scale device is required without requiring a special circuit. (2) Even when a power failure occurs again during charging after recovery from a power failure, the remaining capacity can be calculated correctly. (3) Even when there is a period in which the device is left uncharged (a state in which it is neither charged nor discharged), the remaining capacity can be accurately calculated. (4) If the remaining capacity is low, change the operation mode,
Only the operation of high importance is performed as the degenerate operation mode,
When the number becomes even smaller, the emergency stop mode was set so that the load side could be disconnected without abnormality.

[0007]

A battery remaining capacity calculation apparatus according to the present invention detects history storage means for storing a history of battery usage up to that time, and whether the battery is in a charged state or a discharged state. Charging / discharging state detection means, a clock for measuring the time during which the battery is in a charging state or a discharging state, and a charging function table for calculating the amount of charge from the charging time during the charging state, and the charging obtained from the history The latest charge amount is obtained by adding the charge amount corresponding to the charge time from the above function to the previous charge amount.

Further, when the time in the charged state is a predetermined time or less, it is assumed that there is a charge amount proportional to the time, and when it is longer than the predetermined time, the charge conversion table is used to obtain the charge amount and the function table is set. I changed it.

Furthermore, a discharge function table for calculating the discharge capacity from the load amount and the discharge time in the discharge state is provided, and at the time of recharging after the discharge, the discharge function table is calculated from the remaining capacity stored in the history storage means. The corrected charging time is estimated by using it and added to the recharging time.

Still further, a standing time integration means for detecting whether the battery is in a discharged state or a charged state and integrating a standing time in a standing state which is neither of them, and a fluctuation for correcting the remaining capacity from the accumulated standing time. A coefficient table is provided, and when there is a leaving time, a value obtained by multiplying the above-described corrected charging time by a variation coefficient corresponding to this leaving time amount is added to the recharging time.

Furthermore, a remaining capacity discriminating means for comparing the remaining capacity with a set load electric energy which is a product of a set load amount and a set operating time, and an operation mode designating means for changing the load amount by the discriminated remaining capacity. Based on the comparison discrimination result above, the operation on the load side is in the normal operation mode, the degenerate operation mode in which the operation is limited to reduce the load current, and when the remaining capacity is very small, the load side is abnormal. The emergency stop mode for disconnecting and the operation mode are changed so that there is no.

[0012]

The battery remaining capacity calculating device according to the present invention is
The remaining capacity of the battery at the time of charging is defined as increasing as a function of the charging time, and the initial value of the remaining capacity at that time is determined by storing the history of the charging and discharging states up to that point.

Further, when the state of charge is small, the charge amount is proportional to the charging time, and when the charging time is long, the additional charge amount is determined by another relationship which is not proportional to the charging time.

Further, if there is a discharge time, the correction charge time is calculated by back-calculating from the discharge capacity, and is calculated as an initial correction time or an initial correction value at the time of recharging.

Further, when there is a leaving time which is neither charging nor discharging, a coefficient is obtained from the leaving time, and a value corresponding to the charge capacity before being left is multiplied by the coefficient to make further correction, so that at the time of recharging. It is calculated as the initial correction time or initial correction value of.

Further, by comparing the remaining capacity of the battery with the set load electric energy, the operation mode on the load side is instructed to the load side from the normal operation mode in accordance with the value of the battery remaining capacity. In order to cut off the output in the emergency stop mode by instructing the load side so that the stop operation on the load side does not become abnormal when the remaining battery capacity becomes very small to the degenerate operation mode that acts to limit the operation. To do.

[0017]

【Example】

Example 1. First, an embodiment of claim 2 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the apparatus of this embodiment. In FIG. 1, 1 is a battery that backs up the system load in the event of a power failure, 6 is a charge / discharge state detection unit, 7 is a built-in battery that operates semi-permanently, and 8
Is a charging time measuring unit, and 9 is a discharging time measuring unit. Reference numeral 10 is a charge conversion table or charge function table, 11 is a coefficient multiplication unit for charging time, and 12 is a coefficient multiplication unit or discharge function table for discharging time. 13 is a battery remaining amount calculation unit, 14 is a battery leaving state detection unit, 15 is a battery usage period measurement unit, 16 is a momentary switch,
Reference numerals 17 and 22 are gates, 18 is a battery replacement notification mode (state storage), 19 is a counter, 20 is a display for displaying the battery number, and 21 is a pulse width discrimination section. 23
Is a non-volatile memory, and 24 is a range that can be realized by the arithmetic function of the microprocessor.

The operation during charging will be described based on the above configuration. First, when there is no power failure, the battery 1 is in the charging state, and the charging / discharging state detecting unit 6 outputs the charging state output signal 26.
Is output, and the charging time measuring unit 8 measures the charging time by the timepiece 7. This time measurement is given by the difference between the charging start time t1 after the recovery from the power failure and the time t2 when the charging state output signal 26 stops, t = t1−t2. If this value is smaller than the predetermined value a, coefficient multiplication 1
The calculation of m × t is performed in one portion, and if it is equal to or larger than the predetermined value a, the charge amount is obtained from the charge conversion table 10 as shown in the example of FIG. That is, the relationship between the charging time and the battery charge amount is as shown in FIG. The result is sent to the battery remaining amount calculator 13. Note that, here, the charging is described as the case of initial charging when the state of charge is 0. Recharging when there is remaining capacity is described below.

Example 2. Next, with the same configuration as that of the first embodiment, the correction calculation operation of the remaining capacity at the time of discharging will be described. When a power failure occurs, the power from the battery is supplied to the load side, and the battery starts discharging. The discharge time measuring unit 9 starts measuring the discharge time based on the timepiece 7. This time measurement is based on finding the time difference t as in the charging time measurement. Then, the value of this discharge time t is sent to the discharge function table 12, and the discharge amount determined by the current value of the load and the discharge time t is obtained by referring to this function table. That is, the discharge amount is represented by a functional form of D = f ₂ (n, t), and the value is determined by the load current n and the time t. D is a value that logarithmically decreases with time t using n as a parameter. This result is also sent to the battery remaining amount calculation 13. In the battery remaining amount calculation unit 13, when the battery is discharged, the amount of discharge is subtracted from the amount of charge obtained at the time of charging. That is, (remaining battery amount) = (charge amount) − (discharge amount)

In order to bring the remaining capacity of the battery closer to the actual state, the correction of the remaining amount at the past power failure is carried out by the following method. The correction of the remaining amount at the time of power failure in the past is performed when the power failure occurs in a state where the charging time to the battery is insufficient. If the charging time to the battery is sufficient, the battery is in a fully charged state and this correction is not performed. In this correction, the remaining battery charge calculation unit 13 stores the past charge amount C in the non-volatile memory 23. When a power failure occurs and discharge is started, the discharge amount is checked to obtain the discharge amount D. When it is determined that the battery is not completely discharged, it is deducted from the past charge amount, and when the capacity remains, the remaining amount is converted into the charge time. That is,
Let F [x] be a function of the inverse conversion from the charge amount to the charge time,
Assuming that the current charging time is Tc, the previous charging amount is C _n-1 , and the discharging amount is D _n-1 , (corrected charging time) = Tc + F [k · (C _n-1 −
D _n-1 )]. Then, the second term of the above equation is added as the corrected charging time to the value Tc measured by the charging time measuring unit 8 to obtain the corrected charging amount. Although the discharge amount D = f ₂ (n, t) is used here, the discharge function table 12 is used as a coefficient multiplication unit to calculate the product (n × t) of the coefficient n that varies with the load current and the discharge time t. And if the time is short, set this value to D
It may be defined as = n × t.

Example 3. Next, with the same configuration as that of the first embodiment, a description will be given of an operation of correcting the remaining capacity by leaving the battery unattended. The detection of the state in which the battery is left without being charged or discharged is performed by the battery left state detection unit 14 based on the output of the charge / discharge state detection unit 6. Then, if the battery leaving state is detected, the leaving time integrating unit 2
After measuring the standing time in 8, the fluctuation coefficient r (t) determined by the standing time is determined by the fluctuation coefficient table 29. This value is integrated by the integrated value of the standing time, and the latest corresponding value is sent to the battery remaining amount calculation unit 13. The battery remaining amount calculation unit 13 uses this r (t) to calculate the corrected charging time from the remaining capacity. In this way, the remaining capacity can be correctly calculated even when there is a period in which the battery is left unattended. In addition, if the above-mentioned operation | movement is demonstrated by a relational expression, the charge time after a correction will be as follows. (Charge time after correction) = Tc + F [k · r (t) · (C
_n-1 -D _n-1 )]

Example 4. In the first embodiment, when the charge amount is calculated from the charge time, the calculation is performed in proportion to the time and the subsequent tables. The configuration in this case is shown in FIG.
The coefficient multiplication unit 11 is not provided, and the charge function table 10 determines the charge amount of the battery over the entire charge time. That is,
In this embodiment, these two parts are held as a table in the form of one continuous function, and the charge amount C = f ₁ (t) which is the output with respect to the time t input is determined. The input / output relationship of this f ₁ (t) has the characteristics shown in FIG. 3, for example. By doing so, it is not necessary to calculate the charge amount from the charge time, and the processing time can be shortened.

Example 5. In this embodiment, an operation will be described in which deterioration due to long-term connection and use is corrected and the remaining capacity is calculated even if the battery is not left. The configuration of this embodiment is similar to that of the first embodiment. The correction for the decrease in the battery capacity with the period of use is performed as follows. First, starting from the time when the battery is new, the battery usage period measuring unit 15 measures the period based on the time data from the clock 7. Next, after determining the coefficient w (t) according to the period by the coefficient table 30, the capacity reduction is corrected by multiplying the battery charge amount by this coefficient in the battery remaining amount calculation 13. That is, the corrected charge amount is as follows. (Charge amount after correction of usage period) = w (t) · (Charge amount)

When the battery is replaced, it is essential to reset the use starting point of the use period measuring section 15. This reset is performed only during maintenance, and it is required to have a reliable and simple circuit configuration with a small number of switches. The pulse width discriminating unit 21 in FIG. 1 discriminates whether the time is long (wide pulse width) or short (small pulse width) depending on how long the momentary switch 16 is pressed. Here, if it is pushed for a long time, it should be used as a control signal (battery replacement notification mode setting and battery usage period reset), and if it is short, it should be used as a count-up signal for setting the target battery among multiple batteries. Thus, it becomes possible to reset a plurality of battery usage periods with one switch. The operation when the actual battery is replaced is as follows. First, by pressing the momentary switch 16 for a long time (for example, 5 seconds or more), the pulse width discrimination unit 21 outputs a "wide" signal, the battery notification mode 18 is "positive", and the 25th line is "H". Then the gate 22 is opened. Next, the momentary switch 16
By pressing for a short time, the signal “narrow” is output from the pulse width discriminating unit 21, the counter 19 counts up, and the content is displayed on the display 20. This counter represents the number of a plurality of batteries, and it is possible to select the battery number of which battery is to be reset for the number of times the momentary switch is pressed. After the operator confirms the battery number, if the momentary switch 16 is pressed again for a long time, the gate 22
Since the is open, the usage period of the battery of the battery usage period measuring unit 15 can be reset. Note that a wide pulse width state is used for the control signal, and the circuit configuration does not accept the next pulse unless the battery replacement mode 18 is "positive". Is high.

Example 6. An example in which the battery load is further controlled by using the battery remaining amount calculation result of the first embodiment will be described with reference to the drawings. In FIG. 4, reference numeral 13 is a battery remaining amount calculation unit, 31 is a remaining capacity discriminator, 32 is a normal operation mode load, 33 is a degenerate operation mode load, and 34 is an emergency stop mode load. Reference numeral 35 is a load condition storage unit, 36 is a system operation condition storage unit, and 37 is an operation mode designating unit, which shows a range that can be realized by the arithmetic function of the microprocessor among the above-mentioned elements.

Next, the operation will be described. The battery remaining amount calculation unit 13 performs the battery remaining amount calculation described in the first embodiment and outputs the remaining battery amount. This result is input to the remaining capacity discriminator 31, which discriminates by comparing information from the load condition storage unit 35 and the system operation condition storage unit 36 of the system according to the remaining capacity of the battery. To do. Then, according to the comparison result, the operation mode designating unit 37 switches and designates the load target as one of the normal operation mode load, the degenerate operation mode load, and the emergency stop mode load. The set load electric energy (set load current x set operating time) is obtained from the values in the load condition storage unit 35 and the system operating condition storage unit 36, and this is compared with the remaining capacity. The discrimination level of the discriminator 31 is When the remaining battery capacity α is sufficient for normal operation, power is supplied to the full load in the normal operation mode, and when the remaining battery capacity is less than the battery remaining capacity α and more than the battery remaining capacity β is required, the degenerate operation mode is the lowest. Power is supplied only to the load that needs to be operated for a limited time. When the remaining battery capacity is less than β, as an emergency, the load side is urgently stopped, important registers are saved, and then the load side is disconnected.

The calculation of the battery remaining amount α and the battery remaining amount β is carried out in the discrimination mechanism, and FIG. 5 shows a graph of an example of the calculation. The solid line 38 in the figure indicates the remaining battery amount β
The part that consumes less power than the point C can be represented by (power consumption) x (operating time) = (constant value), and the part that consumes more power than point C cannot be represented by a formula. Find from the table. The dotted line 39 in the figure indicates the battery remaining amount α, and the portion that consumes less power than point D as in 34 is represented by (power consumption) × (operating time) = (constant value). The possible range, the part of which power consumption is larger than the point D, cannot be expressed by a calculation formula and is obtained from a table. On the other hand, the dashed-dotted line 40 represents an example of the relationship between the operating time of the actual battery remaining amount and the power consumption.

[0028]

Since the battery remaining capacity calculating device of the present invention is constructed as described above, it has the following effects.

There is an effect that the remaining capacity can be calculated relatively accurately with a simple structure without using a special element.

Further, there is an effect that the remaining capacity can be calculated relatively accurately by simple calculation and table reference.

Further, even if there is a long or short power failure, the remaining capacity can be calculated by appropriate correction.

Further, even if the battery is left unused without being used, the remaining capacity can be calculated by appropriate correction.

Further, the operation mode can be specified by comparing the remaining capacity of the battery with the set electric energy of the load, and the indispensable operation can be continued even when the remaining capacity is small. There is an effect that the side can be separated so that there is no abnormality.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a battery state-of-charge calculation device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a table for converting a charging time and a charging amount.

FIG. 3 is a characteristic diagram showing a relationship between a charging time and a battery charge amount.

FIG. 4 is a block diagram showing means for designating an operation mode of a battery load in another embodiment of the present invention.

5 is a diagram for explaining the operation of FIG. 4. FIG.

FIG. 6 is a block diagram showing a conventional battery control method.

[Explanation of symbols]

1 Battery 6 Battery Charging / Discharging State Detection Unit 7 Clock 8 Charging Time Measuring Unit 9 Discharge Time Measuring Unit 10 Charging Function Table (Charge Conversion Table) 11 Coefficient Multiplying Unit for Charging Time 12 Discharging Function Table (Coefficient Multiplying Unit for Discharging Time) ) 13 battery remaining amount calculation unit 14 battery leaving state detection unit 15 battery usage period measurement unit 16 momentary switch 17, 22 gate 18 battery replacement notification mode setting unit 19 counter 20 display unit for displaying battery number 21 pulse width discrimination unit 23 Non-volatile memory 28 Left time integration unit 29 Coefficient of variation table 30 Coefficient table of usage period 31 Remaining capacity discriminator 37 Operating mode designating means

Claims (5)

[Claims] 1. A history storage unit that stores a history of battery usage up to that point; a charge / discharge state detection unit that detects whether the battery is in a charged state or a discharged state; It is equipped with a clock that measures the time in the discharge state and a charge function table that calculates the charge amount from the charge time in the charge state.The charge amount before charging obtained from the history corresponds to the charge time from the function. A battery remaining capacity calculation device that adds the charge amounts to obtain the latest charge amount. 2. When the state of charge is less than a predetermined time, it is assumed that there is a charge amount proportional to the time, and when it is more than the predetermined time, the charge amount is obtained from a charge conversion table and replaced with a function table. The battery remaining capacity calculation device according to claim 1, wherein: 3. A discharge function table for calculating a discharge capacity from a load amount and a discharge time in a discharge state is provided, and at the recharge time after discharge, the discharge function table is calculated from the remaining capacity stored in the history storage means. The battery remaining capacity calculation device according to claim 1, wherein a corrected charging time is estimated by using the above and is added to the recharging time. 4. Further, a standing time integrating means for detecting whether the battery is in a discharged state or a charged state and integrating a standing time in a standing state other than the above, and a remaining capacity for correcting the remaining capacity from the accumulated standing time. A coefficient of variation table is provided, and when there is a leaving time, a value obtained by multiplying the correction charging time according to claim 3 by a coefficient of variation corresponding to the amount of leaving time is added to the recharging time. The battery remaining capacity calculation device according to claim 1. 5. Further, a remaining capacity discriminating means for comparing the remaining capacity with a set load electric energy which is a product of a set load amount and a set operating time, and an operation for changing an operation on a load side by the discriminated remaining capacity. With the mode designating means, the operation on the load side is the normal operation mode based on the above comparison discrimination result, the degenerate operation mode in which the load current is reduced by limiting the operation, and the load side is disconnected when the remaining capacity is small. The emergency stop mode and the operation mode of the above are changed.
The battery remaining capacity calculation device described.