JP2014033604A - Charge/discharge state equalization method for battery system, charge/discharge state change method for battery system, and battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge/discharge state equalization method for a battery system, and the battery system for executing the charge/discharge state equalization method, capable of adjusting capacity balance between battery modules without adding a specific circuit to each battery module.SOLUTION: Battery modules 10, 10, and 10 each comprise a creation unit for creating battery voltage data obtained by digitizing charge states of 39 secondary batteries. A CPU 81 of a control unit 8 for polling the battery modules 10, 10, and 10 changes magnitude of a frequency at which battery voltage data is to be acquired by time-sequential polling, on the basis of magnitude of deviation calculated from battery voltage data (or battery voltage itself) individually acquired by polling prior to the time-sequential polling.

Description

  The present invention provides a battery system in which a plurality of battery modules are connected in series and / or in parallel, and includes a control unit that acquires state data of each battery module by polling in time series. The present invention relates to a charge / discharge state equalization method for a battery system and a battery system. The present invention also relates to a charging / discharging state changing method for a battery system and a battery system.

  One useful usage form of the secondary battery is a battery system configured by combining a plurality of battery modules including a plurality of unit cells. For example, it is possible to increase the terminal voltage and / or battery capacity by connecting a plurality of battery modules in series and parallel. In such a battery system, there is a difference in the amount of self-discharge due to the current consumption of the control circuit in each battery module, and thus the capacity balance is lost during storage or charging / discharging is stopped. Further, due to the difference in charge / discharge characteristics of each battery module, the capacity balance is lost even during charge / discharge.

  When charging / discharging is repeated in a state where the capacity balance of each battery module is lost due to the above-described causes, the charging voltage applied to each battery module and the charging / discharging current flowing through each battery module become unequal, resulting in a capacity balance. Therefore, it is important to maintain the capacity balance among the battery modules because there is a tendency that the deterioration of the battery is promoted or the difference in deterioration rate due to the deterioration of the capacity balance is increased.

  On the other hand, in Patent Document 1, in an assembled battery including a plurality of battery blocks in which a plurality of battery cells (unit cells) are connected in series, a cell controller is connected to each battery block, and each cell controller is There is disclosed a technique for adjusting the cell balance in each assembled battery by discharging any battery cell in each corresponding assembled battery with a resistance circuit. It is conceivable to apply this technology to the battery system described above to discharge the capacity of any battery module with a discharge circuit such as a resistor circuit, thereby adjusting the capacity balance between the battery modules in the battery system.

JP 2009-17657 A

  However, the technique disclosed in Patent Document 1 requires a discharge circuit that discharges each battery module, which complicates the circuit and generates extra space on the circuit board, which also increases the cost. Was a problem.

This invention is made | formed in view of such a situation, The place made into the objective is the battery system which can arrange the capacity | capacitance balance between battery modules, without adding a special circuit to each battery module. It is providing the charge / discharge state equalization method and the battery system which performs this charge / discharge state equalization method.
Another object of the present invention is to provide a charge / discharge state change method for a battery system that can reduce the capacity when the capacity of the battery module increases, and a battery system that executes the charge / discharge state change method.

  A method for equalizing charge / discharge states of a battery system according to the present invention includes a plurality of battery modules each having a generation unit that generates state data representing numerically the charge / discharge states of one or a plurality of secondary batteries in series and / or in parallel. In the method of equalizing the charge / discharge state in each battery module in a battery system including a control unit that acquires each of the state data generated by each generation unit by polling the state data generated by each generation unit in time series, the control unit includes: The frequency at which each state data is to be acquired is changed according to the size of each acquired state data.

  The charge / discharge state equalization method of the battery system according to the present invention calculates an average value of each acquired state data, calculates each deviation of each acquired state data with respect to the calculated average value, and calculates each According to the magnitude of the deviation, the frequency with which the state data is to be acquired is changed.

  The charge / discharge state equalization method of the battery system according to the present invention determines whether or not the difference between the maximum and minimum absolute values of the calculated deviations is greater than a predetermined threshold value, The frequency of each acquisition should be changed.

The charge / discharge state equalization method for a battery system according to the present invention is characterized in that the state data is data representing a voltage and / or remaining capacity of the secondary battery.
The charge / discharge state equalization method for a battery system according to the present invention is characterized in that upon receipt of the polling data, the generating unit of the battery module to be polled enters a state of being activated after exiting a state of low power consumption. .
The charge / discharge state equalization method for a battery system according to the present invention is characterized in that the polling data includes periodic data for determining when the generation unit of the polling target battery module is activated.
The method for equalizing charge / discharge states of a battery system according to the present invention is characterized in that an optical fiber is used for communication between the battery module and the control unit.

  The battery system according to the present invention includes a plurality of battery modules connected in series and / or in parallel, each having a generation unit that generates state data that represents numerically the charge / discharge states of one or more secondary batteries. In the battery system including the control unit that acquires each of the state data generated by the generation unit by chronologically polling the frequency, the control unit should acquire the state data according to the size of each acquired state data. It is characterized by changing.

  In the battery system according to the present invention, the control unit calculates a mean value of each acquired state data and a deviation of each acquired state data with respect to the average value calculated by the means. And calculating means for changing the frequency with which the state data should be acquired in accordance with the magnitude of the deviation calculated by the calculating means.

  In the battery system according to the present invention, the control unit includes means for determining whether or not a difference between a maximum value and a minimum value of an absolute value of each deviation calculated by the calculation unit is larger than a predetermined threshold value, When it is determined that the means is large, the frequency of each frequency to be acquired is changed.

In the battery system according to the present invention, the state data is data representing a voltage and / or remaining capacity of the secondary battery.
The battery system according to the present invention is characterized in that upon receipt of the polling data, the generation unit of the battery module to be polled enters a state in which it has started out of a low power consumption state.
The battery system according to the present invention is characterized in that the polling data includes periodic data for determining when the generation unit of the battery module to be polled is activated.
The battery system according to the present invention is characterized in that an optical fiber is used for communication between the battery module and the control unit.
In the battery system according to the present invention, the control unit includes means for determining whether or not each acquired state data is greater than a predetermined threshold value. It is characterized by changing the number.
In the method for changing the charge / discharge state according to the present invention, a plurality of battery modules each having a generation unit that generates state data representing the charge / discharge states of one or a plurality of secondary batteries in numerical values are connected in series and / or in parallel. In the method of changing the charge / discharge state in each battery module in a battery system including a control unit that acquires each of the state data generated by each generation unit in a time-series manner, the control unit acquires each The frequency at which the state data is to be acquired is changed according to the size of the state data.
In the method for changing the charge / discharge state according to the present invention, each determination is made as to whether or not each acquired state data is greater than a predetermined threshold, and if it is determined to be large, the frequency of each acquisition should be changed. Features.
In the method for changing a charge / discharge state according to the present invention, the state data is data representing a voltage and / or remaining capacity of the secondary battery.

In the present invention, a plurality of battery modules are connected in series and / or in parallel, and in each battery module, the generation unit digitizes the charge state (or discharge state) of one or more secondary batteries. Generate state data. And the control part which polls each battery module changes the frequency which should acquire each status data by subsequent time-sequential polling according to the magnitude | size of each status data acquired by polling. In this case, the size of the state data represents the degree of advancement of the charged state (or discharged state), and the battery module communicates by acquiring the state data of each battery module, so that the discharged state is determined by each discharge. Decreases (or discharge state increases).
In other words, when changing the frequency at which each state data is to be acquired from the battery module, changing according to the size of each state data acquired from the battery module can increase each charge state (or discharge state) of the battery module. In order to cope with the change according to the degree, it can be adjusted so that the difference in the degree of advancement of the charged state (or discharged state) in each battery module thereafter is eliminated.

In the present invention, according to the magnitude of the deviation of each acquired state data with respect to the average value of each acquired state data, the frequency of each state data to be acquired by subsequent time-series polling is determined. change.
In this case, calculating the magnitude of the deviation for each acquired state data from the battery module corresponds to calculating the magnitude of the deviation for each degree of advancement of the charged state (or discharged state) of the battery module.
For this reason, according to the large / small (or small / large) deviation calculated for each acquired state data, by changing the number / frequency of the frequency at which each state data should be acquired, Adjustment can be made so that the deviation in the degree of advancement of the charged state (or discharged state) is eliminated.

In the present invention, when the difference between the maximum value and the minimum value is larger than a predetermined threshold among the absolute values of the calculated deviations for each acquired state data, the state data is obtained by subsequent time-series polling. Change the frequency of each acquisition.
For this reason, in addition to preventing the difference in the degree of advancement of the charging state (or discharging state) in each battery module from expanding beyond a certain level, changes in the frequency at which the state data should be acquired are unstable. Thus, it is possible to prevent the occurrence of phenomena such as hunting.

In the present invention, the voltage and / or remaining capacity data of the secondary battery is used as the state data representing the charge / discharge state of the secondary battery included in each battery module.
In other words, when changing the frequency at which each state data should be acquired from the battery module, changing according to the size of each state data acquired from the battery module may be the voltage level of the secondary battery of the battery module and / or In order to cope with the change according to the size of the remaining capacity, it is possible to adjust so that the difference in voltage and / or remaining capacity of the secondary battery in each subsequent battery module is eliminated.
In the present invention, by receiving polling data, the generation unit of the battery module to be polled enters a state where it has been started after exiting the low power consumption state, so that the entire system is energy saving.
In the present invention, since the polling data includes periodic data that determines when the generation unit of the battery module to be polled is activated, the entire system is energy-saving. In general, a light receiving circuit such as a photocoupler used for reception needs to be always activated. In the present invention, even if an optical fiber is used for communication between the battery module and the control unit, the battery module By including the periodic data for determining when to start the battery module, the light receiving circuit of the battery module is not always started, and the entire system is energy saving.

According to the present invention, when changing the frequency at which each state data should be acquired from the battery module, changing the state data acquired from the battery module according to the size of each state data acquired is the state of charge (or discharge state) of the battery module. In order to cope with the change according to each degree of increase in (), it is possible to adjust so as to eliminate the difference in the degree of increase in the charge state (or discharge state) in each subsequent battery module.
Therefore, it is possible to adjust the capacity balance between the battery modules without adding a special circuit to each battery module.
Further, by obtaining the overcharge state data of each battery module, the frequency of communication with the battery module is maximized, and each discharge charge state is reduced (or the discharge state is increased), so that the overcharge state is established. It can be reduced.

It is a block diagram which shows schematic structure of the battery system which concerns on this invention. It is a block diagram which shows the structural example of a battery module. It is a timing chart which shows the operation state of the battery module polled from the control part. It is a timing chart which shows the operation state of the battery module polled from the control part. It is a flowchart which shows the process sequence of CPU which changes the frequency of polling according to the magnitude | size of the battery voltage acquired from each battery module.

Hereinafter, the present invention will be described in detail with reference to the drawings illustrating embodiments thereof.
FIG. 1 is a block diagram showing a schematic configuration of a battery system according to the present invention, and FIG. 2 is a block diagram showing a configuration example of a battery module. In the figure, reference numeral 10 denotes a battery module. The battery modules 10, 10, and 10 (hereinafter also referred to as battery modules A, B, and C in order from the high potential side) are connectors 102 of negative terminals of the battery modules A and B, The battery modules B and C are respectively connected in series with the positive electrode terminal connector 101 by wiring.

The form of connecting a plurality of battery modules 10 is not limited to that shown in FIG. For example, four battery modules 10 connected in series may be connected in parallel, or the number of battery modules 10 connected in series and parallel may be changed as appropriate. When the battery system shown in FIG. 1 is charged, a charging voltage is applied between a connector 101 of the battery module A and a connector 102 of the battery module C from a charger (not shown).

  The battery module 10 includes, for example, 13 pieces of secondary batteries (unit cells) 111, 112, 113, 121, 122, 123,. A battery pack 11 is formed by connecting battery blocks 11, 12,... 23 in series in this order. The number of secondary batteries connected in series and / or in parallel in the assembled battery 1 is not limited to 39. In the battery module 10, the positive side and the negative side of each of the battery blocks 23 and 11 are connected to the positive terminal connector 101 and the negative terminal connector 102 through the charge / discharge path.

  The voltages of the battery blocks 11, 12,... 23 are independently applied to the analog input terminal of the A / D conversion unit 4, converted into digital voltage values, and output from the digital output terminal of the A / D conversion unit 4. , And is supplied to the generation unit 5 composed of a microcomputer. The analog input terminal of the A / D conversion unit 4 is arranged in close contact with the assembled battery 1, and the detection output of the temperature detector 3 that detects the battery temperature of the assembled battery 1 by a circuit including a thermistor, and the assembled battery 1 is provided in the charge / discharge path on the negative electrode side, and a detection output of a current detector 2 comprising a resistor for detecting a charging current and a discharging current of the assembled battery 1 is given. These detection outputs are converted into digital detection values and supplied from the digital output terminal of the A / D conversion unit 4 to the generation unit 5.

  The charge / discharge path on the positive electrode side of the assembled battery 1 is provided with a circuit breaker 7 composed of P-channel type MOSFETs 71 and 72 that cut off the charge current and the discharge current, respectively. The MOSFETs 71 and 72 are connected in series with their drain electrodes butted together. A diode connected in parallel between the drain electrode and the source electrode of each of the MOSFETs 71 and 72 is a parasitic diode (body diode). The MOSFETs 71 and 72 may be N-channel type, or relay switches using electromagnetic force may be used instead of the MOSFETs 71 and 72.

  The generation unit 5 includes a CPU 51. The CPU 51 includes a ROM 52 that stores information such as programs, a RAM 53 that stores temporarily generated information, a timer 54 that measures various times in parallel, and a battery module 10. The I / O port 55 for inputting / outputting each unit is connected to each other by a bus. The I / O port 55 is connected to the digital output terminal of the A / D conversion unit 4, the gate electrodes of the MOSFETs 71 and 72, and the communication unit 6. The communication unit 6 is used to communicate with a control unit 8 described later. The ROM 52 is a non-volatile memory composed of, for example, a flash memory. In addition to the program, the ROM 52 stores, for example, a learning value (learning capacity) of full charge capacity and various setting data.

  The CPU 51 executes processing such as calculation and input / output according to a control program stored in advance in the ROM 52. For example, the CPU 51 takes in the voltage values of the battery blocks 11, 12, and 13 and the detection value of the charging / discharging current of the assembled battery 1 at a cycle of 250 ms, and the charging current of the assembled battery 1 or the Charge power or discharge current or discharge power is integrated, and the charge amount or discharge amount calculated by the integration is stored in the RAM 53. The battery voltage of the assembled battery 1 calculated from the taken voltage values of the battery blocks 11, 12, 13 is also stored in the RAM 53.

The CPU 51 also calculates a remaining capacity based on the accumulated charge / discharge amount, calculates a relative remaining capacity based on the calculated remaining capacity and full charge capacity, and stores these in the RAM 53. The CPU 51 determines whether or not the assembled battery 1 is in a fully charged state (hereinafter also simply referred to as “full charge”). Preferably, the battery voltage of the battery block having the maximum voltage is equal to or higher than the full charge detection start voltage, and When the state where the charging current is equal to or less than the predetermined value continues for a certain time or more, the battery is determined to be fully charged. Further, the CPU 51 generates remaining capacity, relative remaining capacity, and battery voltage data according to the remaining capacity and relative remaining capacity stored in the RAM 53 and the battery voltage of the assembled battery 1, and the generated data is transmitted to the control unit 8. Is transmitted via the communication unit 6 in response to polling.

  The breaker 7 is electrically connected between the drain electrode and the source electrode of each of the MOSFETs 71 and 72 when an ON signal of L (low) level is given from the I / O port 55 to the gate electrodes of the MOSFETs 71 and 72 during normal charge / discharge. It is supposed to be. When the charging current of the assembled battery 1 is cut off, the conduction between the drain electrode and the source electrode of the MOSFET 71 is cut off by applying an H (high) level off signal from the I / O port 55 to the gate electrode of the MOSFET 71. . Similarly, when the discharge current of the battery pack 1 is cut off, the conduction between the drain electrode and the source electrode of the MOSFET 72 is cut off by applying an H (high) level off signal to the gate electrode of the MOSFET 72 from the I / O port 55. Is done. When the MOSFETs 71 and 72 are N-channel type, an on / off signal of H / L level obtained by inverting the above L / H level may be given to the gate electrode. When the assembled battery 1 is in an appropriately charged state, the MOSFETs 71 and 72 of the circuit breaker 7 are both turned on, and the assembled battery 1 is in a state where it can be discharged and charged.

  The control unit 8 communicatively connected to the battery modules 10, 10, and 10 includes a CPU 81. The CPU 81 includes a ROM 82 that stores information such as programs, a RAM 83 that stores temporarily generated information, and various times. A timer 84 that measures time in parallel, an operation / display unit 85, and a communication unit 86 for communicating with the battery modules 10, 10, and 10 are connected to each other via a bus. The operation / display unit 85 is for accepting an operation by a user or displaying an operation state or the like of the battery modules 10, 10, 10. Instead of the operation / display unit 85, functional blocks for communicating with the host device may be connected by a bus.

The communication unit 86 is connected to the clock terminal connector 103 and the data terminal connector 104 of each of the battery modules 10, 10, and 10 through an interface conforming to the RS-485 standard. The clock in this interface is supplied from the communication unit 86. Instead of RS-485, RS-422, RS-232C, I2C (Inter-Integrated Circuit), SMbus
An electrical interface such as (System Management Bus) may be used, or an interface such as an optical fiber may be used. However, since the reference potentials of the signals in the battery modules 10, 10, and 10 are different, the controller 8 and the battery modules 10, 10, and 10 are connected via an insulating circuit regardless of which interface is used. Is done.

The CPU 81 executes processing such as calculation and input / output in accordance with a control program stored in advance in the ROM 82. For example, the CPU 81 sequentially polls the battery modules 10, 10, 10 in time series to acquire the remaining capacity, relative remaining capacity, and battery voltage data of each of the assembled batteries 1, 1, 1. Only a part of these data may be acquired. Each acquired data is stored in the RAM 83 and later read out from the RAM 83 and used for calculation when changing the polling frequency.
Below, the polling performed between the control part 8 and the battery modules 10, 10, and 10 is demonstrated using a timing chart.

3 and 4 are timing charts showing operation states of the battery modules 10, 10, 10 polled from the control unit 8. In the four charts shown in FIGS. 3 and 4, the horizontal axis is the same time axis. From the top of each figure, the battery module to be polled, the operating state of the battery module A, the operating state of the battery module B, and The operating state of the battery module C is shown. During the period in which “wake-up” is displayed in each operation state, polling from the control unit 8 causes the generation unit 5 of the polling target battery module to exit from the low power consumption state (wake up). It becomes a state. This state automatically switches to a low power consumption state (sleep mode) after one polling is completed (for example, after 2 seconds). In addition to the generation unit 5, the communication unit 6 and the A / D conversion unit 4 may also be switched to a low power consumption state, and any circuit portion may not be switched to a low power consumption state. Also good.
In this embodiment, only the battery module to be polled is in a state in which the generation unit 5 exits the low power consumption state and starts up (wakes up), so that the entire system is energy saving.
In the above-described embodiment, polling data is received by polling from the control unit 8, so that the generation unit 5 of the battery module to be polled starts up (wakes up) out of the low power consumption state. However, instead of this, the following polling data may be used.
The polling data includes period data that determines when the generation unit 5 is activated and / or a period during which the activated state is maintained. As a result, the target battery module activates itself based on the periodic data, maintains the activated state during the period for maintaining the activated state, and then automatically (after one polling is completed), and automatically reduces the power consumption. Switch to the state (sleep mode). If it demonstrates with a specific example, as shown in FIG. 4, battery module C will be 4S (second).
, Battery module A wakes up for 2S, and battery module A wakes up for 1S. At this time, the polling data is transmitted to the battery module C after 7S, that is, data (period data) that wakes up for 4S. Thereby, the battery module C wakes up as shown in FIG.
When using such polling data, in addition to the generation unit 5, the communication unit 6 and the A / D conversion unit 4 may be switched to a low power consumption state. It may be possible not to switch to the state.
In particular, when an optical fiber is used for communication between the battery module including the generation unit 5 and the communication unit 6 and the control unit 8, it is usually necessary to always activate the light receiving circuit such as a photocoupler used for reception. However, if the data includes the periodic data of the present embodiment, the battery module including the light receiving circuit can be activated only when necessary, so that the entire system is energy saving.

  Here, the power consumption of the circuit portion (at least the generation unit 5) in the battery module 10 increases and the self-discharge amount also increases when the generation unit 5 is in the activated state than when the generation unit 5 is in the low power consumption state. To increase. By utilizing this fact, by changing the frequency of polling performed from the control unit 8 for the battery module whose capacity balance is lost due to the difference in remaining capacity, relative remaining capacity or battery voltage with respect to other battery modules. The capacity balance between the battery modules 10, 10, 10 can be equalized. Even when the generation unit 5 does not switch to the low power consumption state, if the frequency of polling from the control unit 8 increases, the power consumption in the generation unit 5 increases and the self-discharge amount increases accordingly. I can say that. Note that the frequency of polling performed by the control unit 8 may be changed based on any two or all of the remaining capacity, the relative remaining capacity, and the battery voltage of each of the battery modules 10, 10, and 10. Good.

  FIG. 3 shows a state of polling when the battery voltages of the battery modules A, B, and C are all 40.2 V and the voltage is balanced as shown in FIG. FIG. 4 shows the state of polling when the battery voltages of the battery modules A, B, and C are 40.2 V, 40.1 V, and 40.3 V, for example, and the voltage balance is lost. The total value of the battery voltages of the battery modules A, B, and C is 120.6 V in any of the cases of FIGS.

  In FIG. 3, polling for each of the battery modules A, B, and C starts from time T11, T12, T13 and time T14, T15, T16. The time required for one polling is all equal, and the interval between polling adjacent in time is constant. That is, the frequency of polling for each of the battery modules A, B, and C is adjusted to be equal. As a result, the self-discharge amounts of the battery modules A, B, and C in which the capacity is balanced are the same, and the capacity balanced state is maintained.

Note that the interval between polling adjacent in time may be increased without changing the time required for one polling. Further, after completing one polling cycle for the battery modules A, B, and C, for example, the next polling cycle may be started after a time of 1 to 2 minutes. The same applies to the case of FIG. 4 described later. By performing polling intermittently in this way, unnecessary self-discharge due to polling is reduced.
Furthermore, the order of polling the battery modules A, B, and C may be different between one polling period and another polling period. That is, the polling order of the battery modules A, B, and C in each polling cycle may be changed as appropriate.

  On the other hand, in FIG. 4, polling for each of the battery modules A, B, and C starts from time T21, T22, T23 and time T24, T25, T26. However, unlike the case of FIG. 3, for example, polling for the battery module C is performed four times continuously from time T21 to T22, and polling for the battery module A is performed twice consecutively from time T22 to T23. Is called. This corresponds to the fact that the battery voltages of the battery modules C and A are 0.2V and 0.1V higher than the battery voltage (40.1V) of the battery module B, respectively. Thus, by increasing the polling frequency in the order of the battery modules B, A, and C, the self-discharge amount increases in the order of the battery modules B, A, and C, and the capacity balance between the battery modules A, B, and C is lost. Is finally resolved, and finally converges to polling as shown in FIG. In the present embodiment, for convenience of explanation, it is assumed that the generation unit 5 and the like are alternately switched between the activated state and the low power consumption state in response to polling from the control unit 8. Even when the generating unit 5 or the like is always activated, the self-discharge amount increases if the communication frequency by polling increases. It goes without saying that it becomes possible to equalize

  Below, the typical operation example of the control part 8 mentioned above is demonstrated using the flowchart which shows it. The processing shown below is executed by the CPU 81 in accordance with a control program stored in advance in the ROM 82. However, the polling for each battery module 10, 10, 10 is executed in a process different from the process in FIG. 5 according to the polling frequency changed in the process shown in FIG.

  FIG. 5 is a flowchart showing a processing procedure of the CPU 81 for changing the polling frequency according to the magnitude of the battery voltage acquired from each of the battery modules 10, 10, 10. In the process of FIG. 5, one period of polling for the battery modules 10, 10, 10 is completed, and battery voltage data (state data described in claims) acquired from each battery module 10, 10, 10 is stored in the RAM 83. Is started before the next polling cycle starts.

  In the process shown in FIG. 5, the polling frequency is changed based on the battery voltage data acquired from each battery module 10, 10, 10, but based on the remaining capacity or relative remaining capacity data acquired together with the battery voltage. These may be changed or a combination of these changing algorithms may be used.

When the process of FIG. 5 is started, the CPU 51 reads the battery voltage of each battery module 10, 10, 10 stored in the RAM 83 (S11), and calculates the average value of the read battery voltages (S12: billing). Means for calculating an average value described in the section). The average value here is not limited to the arithmetic average value (arithmetic average value), and may be other average values such as a geometric average value, a median value, and a mode value. The battery voltage data stored in the RAM 83 represents the battery voltage as it is.

  Thereafter, the CPU 81 calculates a deviation of each battery voltage with respect to the calculated average value (calculation means described in claims), calculates an absolute value of the calculated deviation (S13), and calculates the maximum of the calculated absolute values. The difference between the value and the minimum value is calculated (S14). Then, the CPU 81 determines whether or not the calculated difference is larger than a predetermined threshold (for example, 0.05 V) (S15: each determination unit described in claims), and if not so (S15: NO), polling The processing in FIG. 5 is terminated without changing the frequency.

If the difference calculated in step S14 is greater than the predetermined threshold (S15: YES), the CPU 81 changes the polling frequency for each battery module 10, 10, 10 (S16) and ends the process of FIG.
The polling frequency to be changed here is set to be many / 寡 depending on the deviation (signed) calculated in step S13, for example.

  Specifically, for example, when the battery voltages of the battery modules A, B, and C acquired in the immediately preceding polling cycle are 40.2 V, 40.1 V, and 40.3 V, they are calculated in step S12. The average value is 40.2V. Further, the deviations calculated in step S13 for each of the battery modules A, B, and C are 0V, −0.1V, and + 0.1V. Therefore, the battery modules B, A, and C are changed in order of the polling frequency. More specifically, the polling frequency for the battery modules B, A, and C in this case may be 1: 2: 4 as shown in FIG. 4 or 1: 2: 3. It may be.

As described above, according to the present embodiment, three battery modules are connected in series, and in each battery module, the generator generates battery voltage data obtained by quantifying the charge state of 39 secondary batteries. Generate. Then, the controller that polls each battery module determines the battery voltage data by subsequent time-series polling according to the size of the battery voltage data acquired by polling (hereinafter also simply referred to as battery voltage). Change the frequency of each acquisition.
In other words, when changing the frequency at which the battery voltage data should be acquired from the battery module, changing according to the magnitude of the battery voltage acquired from the battery module can be changed according to the degree of increase in the state of charge of the battery module. Therefore, it is possible to adjust so as to eliminate the difference in the degree of progress of the charge state in each subsequent battery module.
Therefore, it is possible to adjust the capacity balance between the battery modules without adding a special circuit to each battery module.

Further, according to the magnitude of the deviation of each acquired battery voltage with respect to the average value of each acquired battery voltage, the frequency with which each battery voltage data should be acquired is changed by subsequent time-series polling.
In this case, calculating the magnitude of the deviation for each battery voltage acquired from the battery module corresponds to calculating the magnitude of the deviation for each degree of increase in the state of charge of the battery module.
Therefore, by changing the number of times each battery voltage data should be acquired according to the magnitude of the deviation calculated for each acquired battery voltage, the degree of charge state enhancement in each battery module thereafter is changed. It is possible to adjust so as to eliminate the deviation.

Further, when the difference between the maximum value and the minimum value among the absolute values of the deviations calculated for each acquired battery voltage is larger than a predetermined threshold, each battery voltage data is acquired by subsequent time-series polling. Change the frequency of power.
For this reason, in addition to being able to prevent the difference in the degree of advancement of the state of charge in each battery module from expanding beyond a certain level, the change in the frequency at which the state data should be acquired becomes unstable, hunting, etc. It is possible to prevent this phenomenon from occurring.

Furthermore, the battery voltage and / or remaining capacity (including relative remaining capacity) data of the secondary battery is used as state data representing the charge / discharge state of 39 secondary batteries included in each battery module.
In other words, when changing the frequency at which each state data such as battery voltage should be acquired from the battery module, the battery voltage of the secondary battery of the battery module can be changed according to the size of each state data acquired from the battery module. The voltage and / or remaining capacity (including the relative remaining capacity) of the secondary battery in each subsequent battery module in order to cope with the change in the height and / or the remaining capacity (including the relative remaining capacity) It is possible to adjust so as to eliminate the difference.
According to the embodiment described above, it is possible to adjust the capacity balance between the battery modules. Furthermore, in the following other embodiments, when the capacity of the battery module increases undesirably, it is possible to reduce the overcharge state. Usually, charging is stopped before such an overcharged state occurs, but an overcharged state may occur due to a failure of a stop switch, a failure of a voltage measurement circuit, or the like.
When 10 unit cells of a lithium ion battery are connected in series, for example, 42.00 V (4.20 V / cell) is set as an overcharge threshold (predetermined overcharge threshold).
For example, when the battery voltages of the battery modules A, B, and C become 42.25V, 40.00V, and 43.25V, the battery modules A and C are overcharged.
In such a case, in FIG. 4, polling for each of the battery modules A, B, and C is performed at time T21,
Starting from T22, T23 and times T24, T25, T26. However, unlike the case of FIG. 3, for example, polling for the battery module C is performed four times continuously from time T21 to T22, and polling for the battery module A is performed twice consecutively from time T22 to T23. Is called. This corresponds to the battery voltage (40.00V) of the battery module B being 1.25V and 0.25V higher than the predetermined threshold of overcharge for the battery modules C and A respectively. Is. Thus, by increasing the polling frequency in the order of the battery modules B, A, and C, the amount of self-discharge increases in the order of the battery modules B, A, and C, the battery voltage decreases, and a predetermined threshold value for overcharging. It becomes below and it can reduce that A and C are an overcharge state. The overcharged state of the battery modules A and C is resolved, and finally converges to polling as shown in FIG.

  In the present embodiment, as the state data representing the charge / discharge states of the battery modules 10, 10, and 10 as numerical values, the battery voltage and / or remaining capacity (where the numerical value indicates the degree of progress of the charged state) (Including relative remaining capacity) is used, but the present invention is not limited to this. For example, data on the amount of discharge from the fully charged state (discharge amount of electricity) in which the magnitude of the numerical value represents the degree of advancement of the discharged state may be used as the state data.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

111, 112, ... 233 Secondary battery 5 Generation unit 6 Communication unit 8 Control unit 81 CPU
82 ROM
83 RAM
86 Communication unit 10 Battery module

Claims (18)

A plurality of battery modules each having a generation unit that generates state data representing the charge / discharge states of one or a plurality of secondary batteries in numerical values are connected in series and / or in parallel, and the state data generated by each generation unit is In a method of equalizing the charge / discharge state in each battery module in a battery system including a control unit that acquires each by polling in time series,
The controller is
A charge / discharge state equalization method for a battery system, characterized in that the frequency at which each state data is to be acquired is changed according to the size of each acquired state data. Calculate the average value of each acquired status data,
Calculate each deviation of each acquired state data from the calculated average value,
The charge / discharge state equalization method for a battery system according to claim 1, wherein the amount of frequency at which the state data is to be acquired is changed according to the magnitude of each calculated deviation. Each determination determines whether or not the difference between the maximum and minimum absolute values of each calculated deviation is greater than a predetermined threshold,
The charge / discharge state equalization method for a battery system according to claim 2, wherein when it is determined that the frequency is large, the frequency of each acquisition is changed.   The charge / discharge state equalization method for a battery system according to any one of claims 1 to 3, wherein the state data is data representing a voltage and / or remaining capacity of the secondary battery. A plurality of battery modules each having a generation unit that generates state data representing the charge / discharge states of one or a plurality of secondary batteries in numerical values are connected in series and / or in parallel, and the state data generated by each generation unit is In a battery system including a control unit that obtains each polling in time series,
The controller is
A battery system characterized in that the frequency with which each status data is acquired is changed according to the size of each acquired status data. The controller is
Means for determining whether each acquired state data is greater than a predetermined threshold,
The battery system according to claim 5, wherein when it is determined that the means is large, the frequency of each acquisition is changed. The controller is
Means for calculating an average value of each acquired state data;
Calculating means for calculating each deviation of each acquired state data with respect to the average value calculated by the means;
6. The battery system according to claim 5, wherein the calculation means changes the frequency with which the state data should be acquired according to the magnitude of each calculated deviation. The controller is
Each of the calculating means includes means for determining whether or not the difference between the maximum and minimum absolute values of the calculated deviations is greater than a predetermined threshold;
The battery system according to claim 7, wherein when it is determined that the means is large, the frequency of each acquisition is changed.   9. The battery system according to claim 5, wherein the state data is data representing a voltage and / or remaining capacity of the secondary battery. The method for equalizing a charge / discharge state of a battery system according to claim 1, wherein the generation unit of the battery module to be polled enters a state of being activated after exiting a low power consumption state by receiving the polling data. . The charge / discharge state equalization method for a battery system according to claim 1, wherein the polling data includes periodic data for determining when the generation unit of the battery module to be polled starts. The charge / discharge state equalization method of the battery system according to claim 11, wherein an optical fiber is used for communication between the battery module and the control unit. 6. The battery system according to claim 5, wherein upon receipt of the polling data, the generation unit of the battery module to be polled enters a state of being started after exiting a state of low power consumption. 6. The battery system according to claim 5, wherein the polling data includes periodic data that determines a timing at which a generation unit of a battery module to be polled is activated. The battery system according to claim 14, wherein an optical fiber is used for communication between the battery module and the control unit. A plurality of battery modules each having a generation unit that generates state data representing the charge / discharge states of one or a plurality of secondary batteries in numerical values are connected in series and / or in parallel, and the state data generated by each generation unit is In a method of changing the charge / discharge state in each battery module in a battery system including a control unit that acquires each time by polling in time series,
The controller is
A method for changing a charge / discharge state of a battery system, wherein the frequency at which each state data is to be acquired is changed according to the size of each acquired state data. Each determination whether or not each acquired state data is larger than a predetermined threshold,
The method of changing a charge / discharge state of a battery system according to claim 16, wherein when it is determined that the frequency is large, the frequency of each acquisition is changed. The method according to claim 16 or 17, wherein the state data is data representing a voltage and / or remaining capacity of the secondary battery.

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