JP4147589B2 - Battery life prediction device and power supply device using the same - Google Patents

Description

  The present invention relates to a battery life prediction device that performs highly accurate life determination of a battery in various electronic devices that are backed up by a battery, and a power supply device such as an uninterruptible power supply using the device.

  Switching power supply devices used in many fields such as computers, communication devices, and medical equipment are usually supplied with an AC input voltage from a commercial power supply. Due to natural disasters, power outages may occur momentarily or for a certain period of time. In such a case, if power is not supplied from the switching power supply device, it may be related to human life or cause social disruption, so it can be charged and discharged as a backup power supply that continues to supply power to the load even during power outages. The battery is equipped.

  However, when the commercial power supply fails and the battery is used, if the battery is deteriorated, it does not play the original role as a backup power supply. Therefore, it is important to always diagnose whether or not the battery has deteriorated when the power supply device is used.

It is known that when the battery is deteriorated, the charging ability is lowered, and therefore, when the battery is discharged by connecting a load, the voltage is rapidly reduced as compared with a normal battery. For example, in Patent Document 1, when a storage battery as a battery reaches a full charge, the charging to the storage battery is terminated and the storage battery is opened. In some cases, a battery deterioration diagnosis apparatus is disclosed in which the capacity of a storage battery is calculated in consideration of the ambient temperature.
JP-A-8-228441

  Compared to other electronic components used in electronic devices, batteries have characteristics that make them especially short-lived under severe operating conditions such as temperature rise, and most of the causes of failure of electronic devices Occupy. However, it is difficult to determine the life of a battery only by its appearance, and the life varies greatly depending on the ambient environmental conditions used and the electrical conditions of the circuit used. Depending on the usage time, load conditions, etc., there is considerable variation and it is difficult to predict at all.

  However, the diagnostic device disclosed in Patent Document 1 cannot measure the capacity of the battery unless it is in a special state immediately after the storage battery is fully charged. Since the open-circuit voltage of the storage battery after the lapse of time is measured, there is a problem that it takes a long time to perform the deterioration determination. In addition, since the test is performed with the battery not connected to the load, it is impossible to accurately determine how much deterioration has progressed for each battery with the load actually connected. It was.

  The present invention has been made paying attention to the above problems, and in a normal use state, a battery life prediction apparatus capable of diagnosing a deterioration state with high accuracy in a short time for each individual battery and the same are used. An object is to provide a power supply device.

  According to the first aspect of the present invention, there is provided charging means for charging a battery, discharging means for discharging the battery, and changing the output current from the battery to the load during the initial use of the battery, and the output current and the voltage between the terminals. Storage means for storing the relationship with the pulsation amplitude value of the battery as a basic data, and periodically discharging the battery by the discharge means during use of the battery, and the pulsation amplitude value of the voltage between the terminals with respect to the output current captured at this time And a diagnostic means for outputting an alarm signal when a difference value between the pulsation amplitude value in the basic data exceeds a set value.

  The present invention has been made by paying attention to the characteristic that the pulsation amplitude value of the inter-terminal voltage at the time of discharge increases because the internal resistance increases as the deterioration of the battery progresses. That is, during normal battery use, this battery is periodically discharged, the output current of the battery at this time and the pulsation amplitude value of the voltage between the terminals are taken into the diagnostic means, respectively, and this pulsation amplitude value is a certain value. When it exceeds the maximum value, an alarm signal is output from the diagnostic means. The pulsation amplitude value of the inter-terminal voltage of the battery that is captured at this time can be measured by slightly discharging the battery, and since it is measured with the load connected, the deterioration state can be accurately detected in a short time. Can be diagnosed.

  The storage means stores, as basic data, the relationship between the output current in the initial state and the pulsation amplitude value of the inter-terminal voltage for each battery, and the diagnostic means stores the pulsation amplitude of the inter-terminal voltage taken in during discharge. Since whether or not to output an alarm signal is determined based on the difference between the value and the pulsation amplitude value of the voltage between terminals corresponding to the output current corresponding to the same output current as at the time of discharging, It is possible to accurately diagnose the deterioration state according to the characteristics.

  According to a second aspect of the present invention, there is provided a battery life prediction apparatus, wherein the diagnosis means comprises life remaining time calculation means for calculating the remaining battery life time based on the difference value and outputting the calculation result. It is.

  With such a life remaining time calculation unit, it is possible not only to output an alarm signal that the battery has reached the end of its life, but also to output how much battery life is remaining, and to determine the battery life time. It becomes possible to know in advance.

  According to a third aspect of the present invention, the diagnostic means comprises a digital signal processor.

  Thus, by using a digital signal processor (DSP) as a diagnostic means, the pulsation amplitude value of the battery terminal voltage can be processed with high resolution and high speed, and basic data for life prediction In addition, since high-speed comparison can be performed, it is possible to predict the life by diagnosing the deterioration state of the battery with high accuracy in a very short time.

  The invention of claim 4 is directed to a power supply device incorporating the battery life prediction apparatus.

  If it does in this way, the battery life prediction apparatus which has the characteristic in this invention will be integrated in power supply device itself.

  According to the first aspect of the present invention, it is possible to provide a battery life prediction apparatus capable of diagnosing a deterioration state with high accuracy in a short time for each battery in a normal use state.

  According to the invention of claim 2, it becomes possible to know in advance the life time of the battery by the output from the diagnostic means.

  According to the invention of claim 3, it is possible to predict the life by diagnosing the deterioration state of the battery with high accuracy in a very short time.

  According to the fourth aspect of the present invention, the battery life prediction device is incorporated in the power supply device, so that the battery life can be reduced by using only single detection information without any external changes to the battery in use. It is possible to provide a power supply device that can accurately diagnose in real time.

  Hereinafter, a preferred embodiment using the battery life prediction apparatus of the present invention will be described with reference to FIGS. 1 and 2 which are attached drawings.

  FIG. 1 shows a case where the battery life prediction apparatus of the present invention is applied to a switching power supply apparatus. In FIG. 1, reference numeral 1 denotes an independent power supply unit as a main power supply unit to which an AC input voltage Vi from a commercial power supply 51 is applied, for example. One or a plurality of AC or DC output voltages Vo are applied to the power supply unit 1. The load 3 is connected. Reference numeral 21 denotes a battery pack attached to the apparatus as a backup power source. Here, in addition to a chargeable / dischargeable battery 22 such as a lithium ion secondary battery or a lead storage battery, preferably an overdischarge that prevents the battery 22 from being overdischarged. A discharge protection circuit and an overcharge protection circuit (both not shown) for preventing overcharge are incorporated together.

  The input terminals 52 and 52 of the power supply unit 1 are connected to a commercial power source 51 as a supply source of the AC input voltage Vi. The input voltage Vi from the commercial power source 51 is obtained by a filter 53 including a rectifier bridge and a boost chopper circuit. The PFC (power factor correction) circuit 54 is converted to a boosted DC voltage VDC1. A DC / DC converter 55 converts the DC voltage VDC1 into a DC output voltage Vo1 suitable for the load 3. The DC output voltage Vo1 is supplied to the load 3 from output terminals 56 and 56 provided in the power supply unit 1. Note that the number of DC / DC converters 55 and the number of DC output voltages Vo1 that can be extracted from the DC / DC converters 55 are not limited to those in the embodiments.

  In this embodiment, in addition to the DC / DC converter 55 that supplies the DC output voltage Vo1 to the load 3, another DC / DC converter 57 that outputs the power supply voltage VCHG for charging the battery 22 from the output terminals 59 and 59 is provided. Is provided. On the other hand, 58 is a battery converter connected so as to bypass the DC / DC converter 57 that outputs the power supply voltage VCHG, which boosts and converts the power supply voltage from the battery 22 when the input voltage Vi decreases or when a power failure occurs. Thus, the DC voltage VDC2 is supplied to the input side of the DC / DC converter 55. As described above, the power supply unit 1 shown here functions as an AC / DC unit that converts the AC input voltage Vi into the DC output voltage Vo1, but functions as an AC / AC unit that supplies the AC output voltage to the load 3. You may have.

  A voltage exchange unit 31 is connected between the power supply unit 1 and the battery pack 21. Here, it is noted that the internal functions of the power supply unit 1 are not changed at all regardless of the battery pack 21 attached to the power supply unit 1 by the functions incorporated in the voltage conversion unit 31. The The voltage conversion unit 31 is provided as an independent module that is separate from the power supply unit 1 and the battery pack 21, but may be detachably provided inside the power supply unit 1 or detachably provided in the battery pack 21. Also good.

  In addition to the battery connection terminals 23 and 23 for connecting the battery pack 21, the voltage conversion unit 31 is a terminal exposed to the outside, and a main body power connection terminal 24 connected to a voltage line for generating the power supply voltage VCHG of the power supply unit 1. , 24 respectively. Further, between the DC / DC converter 57 and the battery 22, there is a function as a charging means for charging the battery 22, and a power supply voltage VCHG from the DC / DC converter 55 according to the specifications of the battery 22. A step-up / step-down unit 25 designed and adjusted so as to step up or step down is inserted and connected. Specifically, when it is known in advance that the optimum charging voltage of the battery 22 is lower than the power supply voltage VCHG from the DC / DC converter 57, a step-down chopper power supply (step-down power supply) that steps down the power supply voltage VCHG to the optimum charging voltage. In contrast, when it is known in advance that the optimum charging voltage of the battery 22 is higher than the feeding voltage VCHG from the DC / DC converter 57, the boosting chopper boosts the feeding voltage VCHG to the optimum charging voltage. A power source (step-up unit) is incorporated.

  Also, a means for detecting the input voltage (feed voltage VCHG) applied to the voltage conversion unit 31 is provided to set / adjust the voltage applied to the battery 22 from the booster / buck unit 25 to the optimum charging voltage of the battery 22. Alternatively, a means for detecting the voltage between the terminals of the battery 22 with respect to a predetermined input voltage may be provided. Further, the voltage conversion unit 31 may be provided with battery discrimination means for physically discriminating the type of the secondary battery, and either the step-down unit or the step-up unit may be operated according to the secondary battery to be used. . In this way, the optimum voltage can be supplied from the voltage conversion unit 31 to the battery pack 21 for any secondary battery.

  On the other hand, a discharge circuit 27 serving as a discharge means for discharging the battery 22 when the input voltage Vi is reduced or when a power failure occurs, bypasses the step-up / step-down unit 25 and from one battery connection terminal 23 which is an output terminal of the voltage conversion unit 31. The discharge line 29 is connected to one main body power connection terminal 24, which is an input terminal of the voltage conversion unit 31, via a diode 28. The diode 28 has a function of preventing the power supply voltage VCHG from the power supply unit 1 from being directly supplied to the battery pack 21 side without going through the step-up / step-down unit 25. In the case where the battery 22 is a lithium ion secondary battery, when a full charge of the battery 22 is detected, the power supply to the battery 22 is stopped and the battery 22 is self-discharged. When detecting that the voltage between the terminals has decreased to a required value, a low voltage detection unit that starts power feeding to the battery 22 may be provided.

  Reference numeral 41 denotes a current transformer as a current detector that detects an output current of the battery 22 when the battery 22 is discharged. The current detector here is not limited to a current transformer. For example, a resistor may be inserted to measure a voltage drop across the both ends. Reference numeral 42 denotes a voltage detection circuit for detecting the voltage between the terminals of the battery 22, which is composed of a series circuit of resistors 43 and 44 connected between both ends of the battery 22, from the connection point of the resistors 43 and 44. A detection voltage proportional to the voltage between the terminals of the battery 22 is output.

  45 supplies a pulse drive signal to a switching element (not shown) built in the step-up / step-down unit 25 and receives detection outputs from the current transformer 41 and the current detection circuit 42 to reduce the deterioration of the battery 22. It is a control device provided with a function as a diagnostic means for diagnosing. 46 indicates, for example, when the output current from the battery 22 to the load is changed during the initial use of the battery 22 before the product is shipped, and the pulsation amplitude value of the output voltage of the battery 22 and the voltage between the terminals (ripple peak). The storage means 46 stores the relationship with the voltage value between peaks as basic data. At that time, the control device 45 converts the detection output from the current transformer 41 and the current detection circuit 42 into a digital signal by the built-in A / D converter, and calculates the pulsation amplitude value of the output current of the battery 22 and the voltage between the terminals. Each is measured and stored in the storage means 46. In particular, the storage means 46 is preferably a non-volatile memory, so that the basic data stored in the storage means 46 before shipment is not lost even if power is not supplied. .

  The control device 45 causes the built-in timer to periodically discharge the battery by the discharging means while the battery 22 is in use, and the pulsation amplitude value of the voltage between the terminals with respect to the output current of the battery 22 taken at this time, and the storage means If the difference value between the pulsation amplitude value for the same output current in the basic data read from 46 exceeds a preset stored value, for example, a diagnostic means for outputting an alarm signal to the output device 47 such as a display device or a notification device Has 48. Further, the diagnostic means 48 here uses a life remaining time calculating means 49 for calculating the remaining life time of the battery 22 using the fact that the pulsation amplitude value of the voltage between the terminals gradually increases as the battery 22 is used. I have. That is, the remaining lifetime calculation means 49 is configured to calculate the pulsation amplitude value of the voltage across the terminals with respect to the output current of the battery 22 captured when the battery 22 is discharged, and the pulsation with respect to the same output current in the basic data read from the storage means 46. It has a function of calculating the remaining life time of the battery 22 based on the magnitude of the difference value from the amplitude value and outputting the calculation result to the output device 47.

  Note that the control device 45 in this embodiment uses a digital signal processor (DSP) in order to increase the calculation speed. That is, the data acquired when the battery 22 is discharged and the basic data stored in the storage means 46 at the time of shipment are compared and calculated under the same output current conditions, and the result is a data table for predicting the lifetime. In comparison, the operation of displaying or notifying the predicted life is performed at high speed and with high accuracy. Here, a battery life prediction device 50 including a control device 45, a storage means 46, an output device 47 and the like is incorporated in the power supply unit 1 which is a power supply device.

  Next, the effect | action is demonstrated about the said structure. When the AC input voltage Vi from the commercial power supply 51 is normally supplied into the power supply unit 1, the AC input voltage Vi is converted into a boosted DC voltage VDC 1 by the filter 53 and the PFC circuit 54. The DC voltage VDC1 from the PFC circuit 54 is applied to the DC / DC converter 55, and the DC output voltage Vo1 obtained by the DC / DC converter 55 is applied to the load 3 connected to the power supply unit 1 and the battery. A power supply voltage VCHG for charging 22 is generated from the DC / DC converter 57. The DC output voltage Vo1 and the feed voltage VCHG are stabilized by a feedback circuit (not shown) built in the DC / DC converters 55 and 57.

  On the other hand, when it is desired to supply power to the load 3 for a certain period of time even when the AC input voltage Vi drops or a power failure occurs, the battery pack 21 and the voltage conversion unit 31 are mounted. As a result, the power supply voltage VCHG from the DC / DC converter 57 is converted to the optimum charging voltage of the lithium ion secondary battery 22 by the boosting / lowering unit 32, and the battery 22 is charged at this optimum charging voltage. Therefore, the battery 22 can be charged with an optimum voltage by simply incorporating the voltage conversion unit 31 corresponding to the battery pack 21 without modifying the inside of the power supply unit 1.

  When the AC input voltage Vi decreases or a power failure occurs in the state where the voltage conversion unit 31 is incorporated, the power supply voltage VCHG applied from the DC / DC converter 57 to the main body power connection terminals 24 and 24 of the voltage conversion unit 31 also decreases. As a result, the diode 28 constituting the discharge circuit 27 is conducted, and power is supplied from the battery 22 to the battery converter 58 of the power supply unit 1. In response to this, the battery converter 58 boosts the power supply voltage from the battery 22 to a DC voltage VDC2 that is substantially the same level as the DC voltage VDC1 from the PFC circuit 54, and this DC voltage VDC2 is input to the DC / DC converter 55. To supply. Therefore, the load 3 connected to the output side of the DC / DC converter 55 continues to receive power supply from the battery 22.

  Next, the operation of the battery life prediction apparatus 50 will be described with reference to the flowchart shown in FIG. 2. In step S1, the power supply unit 1 for the tool is utilized using the main body power connection terminals 24 and 24 at the time of shipment as a product. , The output current from the battery 22 and the voltage between the terminals when the control device 45 cuts off the input voltage Vi from the commercial power source 51 while changing the load 3 are detected from the current transformer 41 and the voltage detection circuit 42. Read by output. At this time, it is preferable to read the voltage between the terminals of the battery 22 several times in the range from no load to full load. The diagnostic means 48 of the control device 45 analyzes the detection output from the voltage detection circuit 42 and calculates the pulsation amplitude value of the voltage across the terminals of the battery 22. The relationship between the output current of the battery 22 thus obtained and the pulsation amplitude value of the voltage between the terminals is stored in the storage means 46 as unique basic data different for each battery 22 (step S2). A data table for predicting the life of the battery 22 is stored in the control device 45 at the time of manufacture.

  Thereafter, the battery pack 21 and the corresponding voltage conversion unit 31 are shipped and combined with the arbitrary power supply unit 1. The operation of the entire power supply apparatus is as described above. In step S3, when the AC input voltage Vi from the commercial power source 51 is normally supplied, the diagnosis unit 48 determines whether or not a certain time for discharging the battery 22 has passed in the next step S4. To do. When a certain time has elapsed, the diagnosis means 48 uses a switch means (not shown) constituting the discharge means to cut off the DC voltage VDC1 from the PFC circuit 54 and instantaneously discharge the battery 22 (step S5). . Then, in the next step S6, the output current from the battery 22 and the voltage between the terminals are continuously read for a short time by the detection outputs from the current transformer 41 and the voltage detection circuit 42, and then the switch means is returned to the original state. Then, the supply of the DC voltage VDC1 from the PFC circuit 54 is resumed (step S7).

  In the next step S8, the diagnosis means 48 analyzes the detection output from the voltage detection circuit 42 and calculates the pulsation amplitude value of the voltage across the terminals of the battery 22. Then, a difference value from the amplitude pulsation value at the same output current is calculated from the basic data at the time of shipment stored in the storage means 46, and the difference value is obtained from a data table for predicting a predetermined life. In step S9, it is determined whether or not the value is exceeded. If data is read in step S6, step S7 and step S8 may be performed simultaneously, or the order may be changed.

  If the pulsation amplitude value of the voltage between the terminals of the battery 22 during the current battery discharge is within the allowable range and the difference value determined in step S9 does not exceed the predetermined value, the normal value is obtained in step S10. Is output to the output device 47, and the output device 47 displays or informs that it is normal, and resets the timer in the next step S12 to prepare for the next discharge check (diagnosis). Further, when the pulsation amplitude value of the voltage between the terminals of the battery 22 at the time of the current battery discharge exceeds the allowable range, and the difference value determined in step S9 exceeds the predetermined value, the battery 21 Is judged to be in a deteriorated state, and an alarm signal is sent to the output device 47. The output device 47 performs display or notification informing the deterioration of the battery 22 in step S11, and resets the timer in the next step S12 to prepare for the next discharge check (diagnosis).

  Further, in addition to the flowchart shown in FIG. 2, the remaining lifetime calculation means 49 included in the diagnosis means 48 uses the difference value obtained in step S8 and the data table stored in the control device 45 in advance to The life remaining time is calculated and a signal indicating the calculation result is sent to the output device 47. In response to this, the output device 47 can display or notify the remaining life time of the battery 22.

  As described above, the battery life prediction apparatus 50 of the above embodiment includes the step-up / step-down unit 25 as charging means for charging the battery 22, the discharge circuit 27 as discharge means for discharging the battery 22, and the initial use of the battery 22. Sometimes, the storage means 46 for storing the relationship between the output current and the pulsation amplitude value of the voltage between the terminals as basic data while changing the output current from the battery 22 to the load 3, 22 is periodically discharged by the discharge circuit 27, and when the difference value between the pulsation amplitude value of the inter-terminal voltage with respect to the output current of the battery 22 captured at this time and the pulsation amplitude value in the basic data exceeds the set value, Diagnostic means 48 for outputting an alarm signal.

  The battery life prediction apparatus 50 of the present embodiment pays attention to the characteristic that the pulsation amplitude value of the voltage between terminals at the time of discharging increases because the internal resistance increases as the deterioration of the battery 22 progresses. It has been made. That is, during normal use of the battery 22, the battery 22 is periodically discharged, and the output current of the battery 22 and the pulsation amplitude value of the inter-terminal voltage at this time are taken into the diagnostic means 48, respectively, and this pulsation amplitude value When the value exceeds a certain value, an alarm signal is output from the diagnostic means 48. The pulsation amplitude value of the voltage between the terminals of the battery 22 taken in at this time can be measured by slightly discharging the battery 22 and is measured with the load 3 connected, so that it can be accurately performed in a short time. The deterioration state of the battery 22 can be diagnosed.

  Further, the diagnostic means 48 according to the present invention includes life remaining time calculating means 49 for calculating the remaining life time of the battery 22 based on the difference value and outputting the calculation result.

  If such a life remaining time calculation means 49 is provided in the diagnosis means 48, it is not only an alarm signal that the battery 22 has reached the end of its life, but also how much the battery 22 has a remaining life time. Can be output, and the life time of the battery 22 can be known in advance.

  Furthermore, since the diagnostic means 48 of the present embodiment is composed of a digital signal processor, the pulsation amplitude value of the voltage between the terminals of the battery 22 can be processed with high resolution and high speed, and life prediction is performed. In addition to the basic data, a high-speed comparison operation can be performed, so that the deterioration state of the battery 22 can be diagnosed with high accuracy in a very short time, and the lifetime can be predicted.

  In addition, the battery life prediction apparatus 50 of this embodiment can be applied to any electronic equipment that is concerned about the life of the battery 22, but in particular, a power supply unit that is a power supply apparatus that needs to constantly supply the DC output voltage Vo 1 to the load 3. 1 is preferably incorporated. In this way, the battery life prediction device 50 having the above characteristics is incorporated in advance in the power supply unit 1 itself.

  In addition, this invention is not limited to the said Example, A various deformation | transformation implementation is possible in the range of the summary of this invention.

It is a circuit diagram which shows the example of application of the battery life prediction apparatus which shows one Example of this invention. It is a flowchart which shows the control procedure of DSP same as the above.

Explanation of symbols

1 Power supply unit (power supply unit)
3 Load
22 battery
25 Booster / Buck unit (charging means)
27 Discharge circuit (discharge means)
48 Diagnostic tools
49 Means for calculating remaining lifetime
50 Battery life prediction device

Claims (4)

The relationship between the output current and the pulsation amplitude value of the voltage between the terminals while changing the output current from the battery to the load during the initial use of the battery, the charging means for charging the battery, the discharging means for discharging the battery Is stored as basic data, and the battery is periodically discharged by the discharging means during use of the battery, and the pulsation amplitude value of the voltage between the terminals with respect to the output current captured at this time is in the basic data A battery life prediction apparatus comprising: a diagnostic unit that outputs an alarm signal when a difference value with a pulsation amplitude value exceeds a set value. 2. The battery life according to claim 1, wherein the diagnostic means includes life remaining time calculating means for calculating a remaining life time of the battery based on the difference value and outputting the calculation result. Prediction device. 3. The battery life prediction apparatus according to claim 1, wherein the diagnosis means is constituted by a digital signal processor. The power supply device according to claim 1, wherein the battery life prediction device is incorporated.

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