Charge / discharge control device

Abstract

The invention relates to a charge / discharge control device. The present invention addresses the problem of uniformizing each battery without adding a special circuit. A BEVECU of a battery module is a device for controlling charging and discharging of batteries of a plurality of battery packs connected in parallel, and the BEVECU of the battery module is provided with: a battery ECU for determining the SOC of each of the plurality of batteries; and a processor of the BEVECU that determines an index value indicating a deviation in the SOC of the plurality of batteries determined by the battery ECU. When the index value exceeds a predetermined value, the system output request for the plurality of batteries from the external system does not exist or there is a margin for the charging / discharging request for the plurality of batteries from the external system. The processor executes homogenization control for reducing the deviation in the SOC of each of the plurality of batteries by performing power exchange between the batteries (steps S111 to S114).

Description

Technical Field

[0001] This invention relates to a charge and discharge control device, and more particularly to a charge and discharge control device for multiple batteries connected in parallel. Background Technology

[0002] Conventionally, there are battery packs formed by connecting individual cells in series (for example, see Patent Document 1). In the battery pack of Patent Document 1, when the deviation of the State of Charge (SOC) of each individual cell is within a specified range, the charging and discharging are controlled in such a way that the charging capacity of the battery pack becomes a first charging capacity. On the other hand, when the deviation of the SOC of each individual cell is not within the specified range, the charging and discharging are controlled so that the charging capacity of the battery pack becomes a second charging capacity that is different from the first charging capacity and moves in a direction that converges towards the deviation.

[0003] Patent Document 1: Japanese Patent No. 4016516 Summary of the Invention

[0004] However, in the battery pack of Patent Document 1, in order to further homogenize the SOC of each individual cell, it is possible to consider adding a special power supply circuit for charging and discharging each individual cell.

[0005] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a charging and discharging control device that can perform uniform charging and discharging of each battery without adding special circuitry.

[0006] The charge / discharge control device of this invention is an apparatus for controlling the charge and discharge of multiple batteries connected in parallel. The charge / discharge control device includes: a determination unit that determines the charge amount of each of the multiple batteries; and a processor that determines an index value representing the deviation of the charge amount of the multiple batteries determined by the determination unit. When the index value exceeds a predetermined value, and when there is no charge / discharge request from an external system for the multiple batteries, or when there is sufficient capacity to accommodate such requests, the processor performs uniform control by exchanging power between the batteries to reduce the deviation of the charge amount of each of the multiple batteries.

[0007] According to this structure, when the index value representing the deviation of the charging amount of multiple batteries exceeds a predetermined value, if there is no charging / discharging request or the charging / discharging request has a margin, the deviation can be reduced by exchanging power between the batteries. As a result, a charging / discharging control device that can perform uniform charging and discharging control of each battery without adding special circuitry can be provided.

[0008] The index value is the SOC difference between the combinations of batteries contained in a multi-cell battery pack. The processor can perform power exchange control between battery combinations that meet the specified condition indicating a large SOC difference as a homogenization control.

[0009] According to this structure, if the SOC difference between the combinations of batteries contained in multiple batteries exceeds a predetermined value, as long as there is no charge / discharge request, the deviation can be reduced by performing control to exchange power between battery combinations that meet the predetermined condition indicating a large SOC difference.

[0010] It may also include multiple relays, which respectively switch multiple batteries to a connected state and a disconnected state with an external system. The processor executes control by switching the relays corresponding to each combination of batteries that meet the specified conditions to the connected state to exchange power.

[0011] According to this structure, if the SOC difference between the combinations of batteries contained in multiple batteries exceeds a predetermined value, and there is no charge / discharge request, control is performed to exchange power by switching the relays corresponding to the combinations of batteries that meet the predetermined condition indicating a large SOC difference to the connected state, thereby reducing the deviation.

[0012] The processor can also terminate the homogenization control when a condition is met that indicates a decrease in the value of an indicator, which represents the deviation in the amount of charge of the battery that is being homogenized.

[0013] Based on this structure, uniformity control can be terminated when the deviation in the charging amount of multiple batteries becomes smaller.

[0014] The processor can interrupt the uniformity control process if a charge / discharge request occurs while it is performing uniformity control.

[0015] This structure allows for a response to charging and discharging requests even while uniformity control is being implemented.

[0016] Invention Effects

[0017] According to the invention, a charging and discharging control device that can perform uniform charging and discharging of each battery without the need for additional special circuitry can be provided. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the structure of the electrical system 1 according to an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram showing the structure of the battery module 10 in this embodiment.

[0020] Figure 3 This is a flowchart illustrating the process of SOC homogenization performed by the BEVECU of the battery module in this embodiment. Detailed Implementation

[0021] Hereinafter, embodiments and variations according to the present invention will be described with reference to the accompanying drawings. In the following description, the same symbols are used to denote the same parts and components. Their names and functions are also the same. Therefore, detailed descriptions of these will not be repeated. Furthermore, the embodiments and variations described below can be selectively combined as appropriate.

[0022] Figure 1 This is a schematic diagram showing the structure of the electrical system 1 according to an embodiment of the present invention. (See reference) Figure 1 Thick solid lines represent high-voltage power lines, thin solid lines represent low-voltage (12V) power lines, and thin dashed lines represent digital or analog signal lines. Electrical system 1 is a system that uses the high-voltage battery and peripheral equipment mounted in the vehicle as a stationary battery. Electrical system 1 includes a power generation unit 22, a power conditioner (hereinafter referred to as "Power Conditioning System (PCS)") 23, a switchboard 30, electrical loads 33, a backup power supply unit (hereinafter referred to as "Uninterruptible Power Supply (UPS)") 34, a step-down transformer 35, a 12V battery 36, battery modules 10AA~10CD, relays 11AA~11CD, 12A~12C, 31, 32, an energy management system (hereinafter referred to as "Energy Management System (EMS)") 100, an interface (IF) - electronic control unit (ECU) 200, and a battery electric vehicle (BEV) - electronic control unit (ECU) 300.

[0023] The power generation device 22 is, for example, a solar power generation device, a wind power generation device, an emergency self-generating device, a fuel cell, or a combined heat and power (CHP) system, which is capable of generating electricity and can be installed on the demand side. A CHP system is a system that uses a diesel engine, gas engine, gas turbine, or fuel cell to generate electricity and uses the exhaust heat for hot water supply, cooling, or heating. The power generation device 22 outputs the generated DC power to the PCS 23.

[0024] Power system 21 is a system that integrates power generation equipment, transformer equipment, transmission equipment, and distribution equipment for supplying electricity to the demand side. Power system 21 supplies AC power to PCS 23.

[0025] As will be described later Figure 2As described herein, battery modules 10AA to 10CD (hereinafter, representatively also referred to as "battery module 10") are modules capable of charging and discharging electricity. In this embodiment, battery modules 10AA to 10CD utilize high-voltage batteries mounted in electric vehicles.

[0026] Relays 11AA~11CD, 12A~12C, 31, and 32 switch the circuit between on (connected) and off (off) states based on control signals from the control device.

[0027] The distribution panel 30 charges the battery modules 10AA-10CD via relays 12A-12C and 11AA-11CD using DC power received from the PCS23. Additionally, the distribution panel 30 supplies DC power discharged from the battery modules 10AA-10CD to the PCS23.

[0028] PCS23 converts the DC power supplied from battery modules 10AA to 10CD via distribution panel 30 into AC power of a specified voltage, and supplies the converted AC power and AC power from power system 21 to electrical loads 33 and UPS 34 and other electrical equipment installed on the demand side via relays 31 and 32. PCS23 converts AC power from power system 21 into DC power of a specified voltage, and converts DC power from generator 22 into DC power of a specified voltage, and supplies the converted DC power to battery modules 10AA to 10CD via distribution panel 30.

[0029] Electrical load 33 includes, for example, electrical equipment such as air conditioners and lighting equipment that consume electricity located on the demand side.

[0030] UPS34 is a device that continues to supply power even in the event of a power outage. UPS34 converts and stores the AC power supplied from the distribution panel 30. When the power supply to the power system 21 from the distribution panel 30 is interrupted, the stored DC power is converted back to AC power and supplied to other electrical equipment via the distribution panel 30. Furthermore, UPS34 outputs the stored DC power to the step-down transformer 35.

[0031] EMS100, also known as xEMS, is a system for properly monitoring and managing energy usage on the demand side. EMS100 includes Home EMS (HEMS), Building EMS (BEMS), and Factory EMS (FEMS). EMS100 is equipped with a processor and memory.

[0032] The IF-ECU200 is a device that controls communication between ECUs and with external devices, and it has a processor and memory.

[0033] The BEV-ECU300 is a device that controls the drive system and battery module 10 of an electric vehicle, and includes a processor and memory. The BEV-ECU300 is commonly used in electric vehicles.

[0034] The step-down transformer 35 reduces the voltage of the DC power supplied from the UPS 34 to 12V and charges the 12V battery 36. The 12V battery 36 stores the 12V DC power from the step-down transformer 35 and outputs the stored 12V DC power to electrical devices that operate on 12V (e.g., IF-ECU 200, BEV-ECU 300, BEVECU 110, battery ECUs 121A to 121C, and MGECUs 131A to 131C, which are internal control devices of the battery module 10 described later).

[0035] Figure 2 This is a schematic diagram showing the structure of the battery module 10 according to this embodiment. (See reference) Figure 2 The two bundles of thick solid lines represent high-voltage DC power lines, and the thin dashed lines represent signal lines for digital or analog signals. The battery module 10 includes a battery pack 120A to 120C (hereinafter, representatively also referred to as "battery pack 120"), a power control unit (PCU) 130A to 130C, a terminal block 140, an auxiliary relay 150, and a BEVECU 110.

[0036] Battery packs 120A to 120C each include battery ECUs 121A to 121C, batteries 122A to 122C, and system main relays (SMRs) 123A to 123C (hereinafter also referred to as "SMR123"). In this embodiment, battery packs 120A to 120C are battery packs that utilize high-voltage batteries mounted in electric vehicles. Therefore, since battery packs 120A to 120C are used in electric vehicles, their degradation levels are prone to differ. Consequently, even when battery packs 120A to 120C are used in the same manner, the way their State of Charge (SOC) changes can easily differ, leading to SOC deviations.

[0037] Batteries 122A to 122C include battery packs consisting of multiple battery cells connected in series and sensor types. The sensor types include voltage sensors for detecting the voltage of each battery cell, current sensors for detecting the current flowing through the battery pack, and temperature sensors for detecting the temperature of various parts of the battery pack. Alternatively, batteries 122A to 122C may replace the battery pack and consist of a single battery cell.

[0038] SMR123A to 123C, based on control signals from battery ECU121A to 121C, will set the circuit for exchanging power between batteries 122A to 122C and external devices to either a connected or disconnected state.

[0039] Battery ECUs 121A to 121C each have a processor and a memory, and control the battery packs 120A to 120C as a whole. Battery ECUs 121A to 121C process sensor signals from batteries 122A to 122C, or control the charging and discharging of batteries 122A to 122C by controlling SMRs 123A to 123C, or calculate the charge level or SOC of batteries 122A to 122C using known methods.

[0040] PCUs 130A to 130C each include a motor generator (MG) ECU 131A to 131C, a converter 132A to 132C, and an inverter 133A to 133C. In this embodiment, PCUs 130A to 130C are mounted on an electric vehicle, and utilize the power generation and regeneration of the motor generator that controls the electric vehicle.

[0041] Converters 132A to 132C respectively convert the voltage of batteries 122A to 122C in battery packs 120A to 120C between the voltage of electrical equipment connected to the distribution panel 30.

[0042] When inverters 133A to 133C are installed in electric vehicles, they perform power conversion between DC power from converters 132A to 132C and AC power from the outside. However, in this electrical system 1, no power conversion is performed.

[0043] Each of the MGECUs 131A to 131C has a processor and a memory. The MGECUs 131A to 131C control converters 132A to 132C to convert DC power from battery packs 120A to 120C into DC power of a specified voltage and output it to terminal block 140, or to convert DC power from terminal block 140 into DC power of the voltage of battery packs 120A to 120C and output it to battery packs 120A to 120C.

[0044] Terminal block 140 has terminals for connecting PCU130A-130C and auxiliary relay 150, and electrically connects PCU130A-130C and auxiliary relay 150.

[0045] The auxiliary relay 150, based on the control signal from the BEVECU 110, sets the circuit that exchanges power between the terminal block 140 of the battery module 10 and external electrical equipment to either a connected or disconnected state.

[0046] The BEVECU110 has a processor and memory, and controls the entire battery module 10 according to instructions from an external ECU. The BEVECU110 controls the power exchange between the battery packs 120A to 120C and external electrical devices via the PCUs 130A to 130C.

[0047] Conventionally, in battery packs such as the battery 122A-122C included in the battery pack 120A-120C of the battery module 10 of the aforementioned electrical system 1, when the deviation of the State of Charge (SOC) of each individual battery cell is within a specified range, there is a case where charging and discharging is controlled to make the charging capacity of the battery pack reach a first charging capacity. On the other hand, in such battery packs, when the deviation of the SOC of each individual battery cell is not within the specified range, the charging capacity of the battery pack differs from the first charging capacity, and charging and discharging are controlled in such a way that it becomes a second charging capacity that moves in the direction of deviation convergence.

[0048] However, in such battery packs, in order to further homogenize the SOC of each individual cell, it is advisable to add a special power supply circuit for charging and discharging each individual cell.

[0049] Therefore, the electrical system 1 includes: a determination unit that determines the charge amount of the plurality of batteries 122A to 122C respectively; and a processor that determines an index value representing the deviation of the charge amount of the plurality of batteries 122A to 122C determined by the determination unit. When the index value exceeds a predetermined value, and when there is no charge / discharge request from the external system for the plurality of batteries 122A to 122C or when there is sufficient capacity to handle charge / discharge requests from the external system for the plurality of batteries 122A to 122C, the processor performs uniform control by exchanging power among the batteries 122A to 122C to reduce the deviation of the charge amount of each of the plurality of batteries 122A to 122C.

[0050] Therefore, if the index value indicating the deviation of the charging amount of multiple batteries 122A to 122C exceeds the specified value, and there is no charging / discharging request, the deviation can be reduced by exchanging power between batteries 122A to 122C. As a result, the charging amount of each battery 122A to 122C can be homogenized without adding special circuitry.

[0051] Figure 3 This is a flowchart illustrating the SOC homogenization process performed by the BEVECU110 of the battery module 10 in this embodiment. (See reference...) Figure 3 The SOC homogenization process is invoked and executed by the BEVECU110 from the higher-level processor at each specified cycle.

[0052] The processor of BEVECU110 determines whether the system output request is 0kW (step S111). The system output request is a request from an external processor (e.g., the processor of BEV-ECU300 in electrical system 1) for output power from battery module 10. If it is determined that the system output request is 0kW ("Yes" in step S111), the processor of BEVECU110 calculates the SOC difference between adjacent battery packs 120 (step S112). Here, the SOC difference between battery pack 120A and battery pack 120B, the SOC difference between battery pack 120B and battery pack 120C, and the SOC difference between battery pack 120C and battery pack 120A are calculated.

[0053] Furthermore, when the system output request is 0kW, the auxiliary relay 150 in the battery module 10 is controlled by the BEVECU 110 to be in a cut-off state. That is, the battery module 10 is set to a state where it cannot exchange power with the outside.

[0054] The processor of BEVECU110 determines whether there is an adjacent battery pack 120 with a SOC difference of A% or more calculated in step S112 (step S113). A% is, for example, 10%, but is not limited to this and can be other values. If it is determined that there is an adjacent battery pack 120 with a SOC difference of A% or more ("yes" in step S113), the processor of BEVECU110 controls the SMR123 of the corresponding battery pack 120 only to the state of external connection, i.e., the on state (step S114), and switches the homogenization flag corresponding to the battery pack 120 to the on state (step S115). The homogenization flag is a flag indicating whether homogenization control of SOC between adjacent battery packs 120 is being performed. When the homogenization flag is on, it indicates that homogenization control is being performed; on the other hand, when the flag is off, it indicates that homogenization control is not being performed. Thus, power is supplied by current flowing from the battery pack 120 with high SOC (i.e., high voltage) to the battery pack 120 with low SOC (i.e., low voltage) in which SMR123 is set to the on state, thereby equalizing the SOC.

[0055] If the system output request is not 0kW ("No" in step S111), or if there is no adjacent battery pack 120 with a SOC difference of more than A% between adjacent battery packs 120 ("No" in step S113), or after step S115, the processor of BEVECU110 determines whether the uniformization flag is in the on state (step S121).

[0056] If the condition is that the homogenization flag is in the on state ("Yes" in step S121), the processor of BEVECU110 calculates the SOC difference between adjacent battery packs 120 (step S122). The processor of BEVECU110 determines whether the SOC difference is less than B% (B < A) (step S123). B% is, for example, 1%, but is not limited to this; any value less than A% is acceptable.

[0057] If the SOC difference is determined to be below B% ("Yes" in step S123), the processor of BEVECU110 controls the SMR123 of the corresponding battery pack 120 to be in a state of being cut off from the outside, i.e., the cut-off state (step S124), and switches the homogenization flag corresponding to the battery pack 120 to the cut-off state (step S125).

[0058] If the SOC difference is determined to be less than B% ("No" in step S123), or after step S125, the processor of BEVECU110 determines whether the system output request exceeds 0kW (step S126).

[0059] If the system output request is determined to exceed 0kW ("Yes" in step S126), the processor of BEVECU110 controls the SMR123A-123C of all battery packs 120A-120C to the on state (step S127). Then, the processor of BEVECU110 sets the homogenization flag of all battery packs 120A-120C to the off state (step S128), and controls battery packs 120A-120C, PCU130A-130C and auxiliary relay 150 to start outputting power corresponding to the system output request (step S129).

[0060] If it is determined that the flag is not in the conducting state during homogenization ("No" in step S121), or if it is determined that the system output request does not exceed 0kW ("No" in step S126), or after step S129, the processor of BEVECU110 returns the executed processing to the upper-level processing of the calling source of the SOC homogenization processing.

[0061] [Variation Example]

[0062] (1) In the aforementioned embodiments, Figure 3 The SOC homogenization process shown is performed by the battery ECUs 121A-121C of the battery packs 120A-120C. However, it is not limited to this; the SOC homogenization process can also be performed by other processors, such as the BEVECU 110 of the battery module 10, the MGECU 131A-131C of the PCUs 130A-130C, or the processors of the BEV-ECU 300 or EMS 100 of the electrical system 1.

[0063] (2) In the aforementioned embodiments, such as Figure 3 As described in step S113, when the SOC difference between adjacent battery packs 120 is greater than A%, SOC homogenization control among battery packs 120 is performed. However, this is not a limitation; homogenization control can be performed whenever it can be determined that there is a deviation in the charging amount of multiple batteries (e.g., battery pack 120). Specifically, this means that the index value representing the deviation in the charging amount of multiple batteries exceeds a predetermined value. For example, this index value can be the difference between the maximum and minimum SOC or charging amount of multiple batteries, the deviation from a reference value such as the average or median value of the SOC or charging amount of multiple batteries, or the variance or standard deviation of the SOC or charging amount of multiple batteries.

[0064] (3) In the foregoing embodiments, such as Figure 2 As shown, the SOC or charge level of batteries 122A to 122C is determined by the processors of battery ECUs 121A to 121C, respectively. However, the determination of the SOC or charge level of batteries 122A to 122C is not limited to this; it can also be performed by other processors, such as the processors of BEVECU110 or MGECU131A to 131C.

[0065] (4) In the foregoing embodiments, such as Figure 3 As shown in step S114, only the SMR123 of the corresponding battery pack 120 is set to the on state. However, it is not limited to this, and the SMR123A to 123C of all battery packs 120A to 120C can also be set to the on state.

[0066] (5) In the foregoing embodiments, such as Figure 2 and Figure 3 As shown, uniformity control is performed among the battery packs 120 included in the battery module 10. However, it is not limited to this, and uniformity control can also be performed among the battery modules 10.

[0067] (6) In the foregoing embodiments, such as Figure 3As shown in steps S114 and S124, uniform control is performed to supply power from the battery pack 120 with a high SOC to the battery pack 120 with a low SOC. If the SOC difference decreases, the uniform control ends. However, this is not a limitation. For the battery pack 120 with a low SOC, after the uniform control ends, the SOC can be further improved by comparing the SOC of other battery packs 120 with power from an external source. This can improve the SOC of the battery pack 120 where the SOC decreases more rapidly due to a decrease in State of Health (SOH).

[0068] (7) When the system output request exceeds 0kW, as long as the power is met only by the battery pack 120 with no decrease in SOH, the power may not be output from the battery pack 120 with a decrease in SOH.

[0069] (8) In the foregoing embodiments, such as Figure 3 As shown in step S111, when the system output request is 0kW, uniformity control is performed. However, it is not limited to this. Even when the system output request exceeds 0kW, a portion of the battery pack 120 can be used to meet the charging and discharging power required by the system output request. When there is a surplus of charging and discharging power in the battery pack 120, uniformity control can be performed in parallel with the exchange of charging and discharging power corresponding to the system output request.

[0070] For example, if there is a State of Charge (SOC) difference between the battery modules 10 subordinate to relay 12A, and the battery modules 10BA-BD and CA-CD subordinate to relays 12B and 12C can meet the system's charging and discharging power requirements, relay 12A is controlled in the off state, and the relays (e.g., relays 11AA and 11AB) between the battery modules 10 of the battery pack 120, which includes power exchange, are controlled in the on state, and the SMR 123 of the battery pack 120 included in the battery module is controlled in the on state. Thus, power is supplied by current flowing from the battery pack 120 of the battery module 10 with high SOC (i.e., high voltage) to the battery pack 120 of the battery module 10 with low SOC (i.e., low voltage), thereby equalizing the SOC. In the equalization control, if the battery modules 10BA-BD and CA-CD subordinate to relays 12B and 12C cannot provide the charging and discharging power, the equalization control is immediately stopped, and relay 12A is controlled in the on state.

[0071] Furthermore, for example, if the SOC difference between battery packs 120A and 120B of battery module 10AA under relay 12A is A% or more (the SOC of battery pack 120A is higher than that of battery pack 120B), and the charging and discharging power required by the system can be met in battery modules 10AB to 10AD other than battery module 10AA under relay 12A, as well as battery modules 10BA to BD and CA to CD under relay 12B and relay 12C, then relay 11AA of battery module 10AA is controlled in the off state, and SMRs 123A and 123B of battery packs 120A and 120B of battery module 10AA are controlled in the on state (specifically, the SMRs 123A and 123B of battery packs 120A and 120B of battery module 10AA are executed). Figure 3 (SOC equalization processing). Therefore, in battery module 10AA, power is supplied by current flowing from battery pack 120A (high SOC, high voltage) to battery pack 120B (low SOC, low voltage), thereby equalizing the SOC. In the equalization control, if the charging and discharging power cannot be supplied by battery modules AB-AD other than those subordinate to relay 12A, or by battery modules 10BA-BD and CA-CD subordinate to relays 12B and 12C, the equalization control is immediately stopped, and relay 11AA is turned on.

[0072] (9) The aforementioned embodiments can be understood as the disclosure of a charging and discharging system or battery module 10 of electrical system 1, or the disclosure of a charging and discharging control device of electrical system 1 or battery module 10 of battery ECU 121A-121C, BEVECU 110, MGECU 131A-131C, BEV-ECU 300 or EMS 100, or the disclosure of a charging and discharging control method or charging and discharging control program executed by the charging and discharging control device.

[0073] [Summarize]

[0074] (1) As Figure 1 and Figure 2 As shown, the BEVECU110 of the battery module 10 is a device for charging and discharging multiple batteries (e.g., batteries 122A to 122C of battery packs 120A to 120C) connected in parallel. It includes: a determination unit (e.g., battery ECUs 121A to 121C, BEVECU110) that determines the charge amount (e.g., SOC) of the multiple batteries respectively; and a processor (e.g., the processor of BEVECU110) that determines an index value representing the deviation of the charge amount of the multiple batteries determined by the determination unit.

[0075] like Figure 3As shown, when the index value exceeds the specified value, if there is no charge / discharge request (e.g., system output request) from the external system for multiple batteries or if there is a margin for charge / discharge request from the external system for multiple batteries, the processor performs uniform control to reduce the deviation of the charge amount of multiple batteries by exchanging power between batteries (e.g., steps S111 to S114).

[0076] Therefore, if the index value representing the deviation of the charging amount of multiple batteries exceeds a predetermined value, and if there is no charging / discharging request or there is a surplus of charging / discharging request, the deviation can be reduced by exchanging power between the batteries. As a result, uniform control of each battery can be performed without adding special circuitry. Furthermore, uniform control can be performed without purchasing power from the power system 21 or using power from the generator 22.

[0077] (2) Figure 3 As shown, the index value is the SOC difference between the combinations of batteries contained in a plurality of batteries. The processor can perform control as uniformization control to exchange power between combinations of batteries that meet a specified condition indicating a large SOC difference (e.g., a SOC difference of A% or more). (e.g., step S114).

[0078] Therefore, when the SOC difference between combinations of batteries contained in a multi-cell battery exceeds a predetermined value, as long as there is no charge / discharge request, deviation can be reduced by implementing control to exchange power between battery combinations that meet the predetermined condition indicating a large SOC difference. Furthermore, by exchanging power between adjacent batteries, losses caused by wiring resistance can also be reduced.

[0079] (3) Figure 2 As shown, it also includes multiple relays (e.g., SMR123A to 123C) for switching the connection status of multiple batteries to an external system and the disconnection status. Figure 3 As shown, the processor can perform control by switching the relays corresponding to each combination of batteries that meet the specified conditions to a connected state to exchange power (e.g., step S114).

[0080] Therefore, if the SOC difference between the combinations of batteries contained in a multi-battery system exceeds a specified value, and there is no charge / discharge request, control is performed to exchange power by switching the relays corresponding to the combinations of batteries that meet the specified condition indicating a large SOC difference to the connected state, thereby reducing the deviation.

[0081] (4) Figure 3As shown, the processor can end the homogenization control when a condition indicating a decrease in the index value is met (e.g., the SOC difference is less than B%), where the index value represents the deviation in the amount of charge of the battery that is performing homogenization control (e.g., steps S121 to S124).

[0082] Therefore, when the deviation in the charging amount of multiple batteries becomes smaller, the homogenization control can be terminated.

[0083] (5) Figure 3 As shown, the processor can interrupt the uniformity control if a charge / discharge request occurs while the uniformity control is being executed (e.g., steps S121, S126, and S127).

[0084] Therefore, it can respond to charging and discharging requests even when uniformity control is being implemented.

[0085] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the invention is not shown in the description of the above embodiments, but is indicated by the technical solutions, and is intended to include all modifications within the meaning and scope equivalent to the technical solutions.

[0086] Symbol Explanation

[0087] 1-Electrical system; 10, 10AA~10CD-Battery modules; 11AA~11CD, 12A~12C; 31, 32-Relays; 21-Power system; 22-Generator; 23-PCS; 30-Distribution panel; 33-Electrical load; 34-UPS; 35-Step-down transformer; 36-12V battery; 100-EMS; 110-BEVECU; 120, 120A~120C- Battery pack, 121A~121C - battery ECU, 122A~122C - battery, 123, 123A~123C - SMR, 130A~130C - PCU, 131A~131C - MGECU, 132A~132C - converter, 133A~133C - inverter, 140 - terminal block, 150 - auxiliary relay, 200 - IF - ECU, 300 - BEV - ECU.

Claims

1. A charge / discharge control device, comprising a charge / discharge control device for multiple batteries connected in parallel, characterized in that it includes: The determining unit determines the charge amount of each of the plurality of batteries; and The processor determines an index value representing the deviation of the charge amount of the plurality of batteries as determined by the determining unit. When the index value exceeds the specified value, and when there is no charge / discharge request from the external system for the plurality of batteries or when there is a margin for charge / discharge requests from the external system for the plurality of batteries, the processor performs uniform control to reduce the deviation of the individual charge amounts of the plurality of batteries by exchanging power between the batteries.

2. The charging and discharging control device according to claim 1, characterized in that, The index value is the SOC difference between the combinations of batteries included in the plurality of batteries. The processor performs control as the homogenization control to exchange power between combinations of batteries that meet a specified condition indicating a large SOC difference.

3. The charging and discharging control device according to claim 2, characterized in that, It also has: Multiple relays, each corresponding to a switch between connected and disconnected states of the multiple batteries to the external system. The processor performs control by switching the relays corresponding to each combination of batteries that meet the specified conditions to a connected state to exchange power.

4. The charging and discharging control device according to claim 1, characterized in that, The processor terminates the homogenization control when the condition indicating that the index value is decreasing is met. The index value indicates the deviation of the charge amount of the battery during the homogenization control process.

5. The charging and discharging control device according to claim 1, characterized in that, If a charge / discharge request occurs while the processor is performing the homogenization control, the homogenization control is interrupted.

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