Battery cluster balancing control method

Abstract

Disclosed in the present application is a battery cluster balancing control method, relating to the field of energy storage systems. The battery cluster balancing control method comprises: acquiring at least one of a first actual state of charge and an actual state of health of each battery cell, and a second actual state of charge of each pack; on the basis of at least one of the first actual state of charge and the actual state of health, by means of a first balancing module, controlling at least one of the state of charge balance and the state of health balance of each battery cell; and, on the basis of the second actual state of charge, by means of a second balancing module, controlling the state of charge balance of the pack.

Description

Balancing control method for battery cluster

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number: 202410728047.3, application date: June 5, 2024; 202311275716.8, application date: September 28, 2023, and claims the priority of the Chinese patent application. The entire content of the Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of energy storage systems, and in particular to a method for balancing and controlling a battery cluster. Background Art

[0004] With the development of energy storage technology, 1000-1500V DC buses have gradually become the mainstream of the industry. However, the voltage of single cells is relatively low, and the number of battery strings needs to be continuously increased to meet the DC bus voltage requirements. The number of packs within a battery cluster and the number of battery cells within a pack are both on the rise. However, the increase in the number of battery strings will further lead to the short-board effect of widening the difference in battery consistency.

[0005] In related technologies, installation and operation and maintenance personnel need to spend a lot of time charging and discharging the PACK individually to meet the battery consistency requirements of the battery cluster. There are also safety hazards in these manual charging and discharging operations. If there is any carelessness, the PACK may short-circuit and then cause thermal runaway of the energy storage system.

[0006] Summary of the Invention

[0007] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a battery cluster balancing control method that can effectively ensure the normal and efficient operation of the battery cluster while reducing system cost and complexity, and has high reliability.

[0008] In a first aspect, the present application provides a balancing control method for a battery cluster, wherein the battery cluster includes at least one PACK, and the PACK includes at least one battery cell. The method includes:

[0009] Obtain at least one of a first actual state of charge and an actual state of health of each of the battery cells, and a second actual state of charge of each of the packs;

[0010] Based on at least one of the first actual state of charge and the actual state of health, controlling at least one of state of charge balancing and state of health balancing of each of the battery cells through a first balancing module;

[0011] Based on the second actual state of charge, controlling the state of charge balancing of the PACK through a second balancing module;

[0012] The first balancing module and the second balancing module are connected to the PACK respectively.

[0013] According to the balancing control method of the battery cluster of the present application, by distinguishing different balancing purposes, a first balancing module for balancing the differences between battery cells and a second balancing module for balancing the differences between packs are respectively set up. While reducing the system cost and complexity, it can effectively ensure the normal and efficient operation of the battery cluster, improve the consistency of the battery, thereby reducing the short board effect; and has high reliability.

[0014] According to one embodiment of the present application, the first balancing module includes a first sub-balancing module. Based on at least one of the first actual state of charge and the actual state of health, the first balancing module controls at least one of state of charge balancing and state of health balancing of each battery cell, including:

[0015] When the difference between the first actual state of charge of a first target battery cell and the first actual state of charge of a first lowest cell among the at least one battery cell is greater than a first preset value, the first sub-balancing module is adjusted to balance the state of charge of the first target battery cell; wherein the first lowest cell is the battery cell with the lowest first actual state of charge among the at least one battery cell.

[0016] According to one embodiment of the present application, the first sub-balancing module includes at least one first switch connected in parallel with the at least one battery cell in a one-to-one correspondence, and a first resistor provided between the first switch and the battery cell connected in parallel with the first switch;

[0017] The adjusting the first sub-balancing module to perform state of charge balancing on the first target battery cell includes:

[0018] controlling a first switch connected in parallel with the first target battery cell to close;

[0019] When the difference between the first actual state of charge of the first target battery cell and the first actual state of charge of the first lowest cell is less than a second preset value, the first switch connected in parallel with the first target battery cell is controlled to be disconnected, and the second preset value is less than the first preset value.

[0020] According to one embodiment of the present application, the first balancing module includes a second sub-balancing module, and the control of at least one of state of charge balancing and health state balancing of each battery cell through the first balancing module based on at least one of the first actual state of charge and the actual health state includes:

[0021] When the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is greater than a third preset value, the second sub-balancing module is adjusted to balance the health state of the second lowest cell; wherein the first highest cell is the battery cell with the highest actual health state among the at least one battery cell, and the second lowest cell is the battery cell with the lowest actual health state among the at least one battery cell.

[0022] According to one embodiment of the present application, the second sub-balancing module includes at least one electromagnetic induction module provided in a one-to-one correspondence with the at least one battery cell, a first end of the electromagnetic induction module is connected to the positive electrode of the battery cell, a second end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a second resistor and a second switch connected in series, a third end of the electromagnetic induction module is connected to the positive electrode of the battery cell, and a fourth end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a third resistor and a third switch connected in series;

[0023] The adjusting the second sub-balancing module to balance the health status of the second lowest cell includes:

[0024] The second switch and the third switch corresponding to the second lowest cell are controlled to be closed in sequence.

[0025] According to one embodiment of the present application, controlling the charge state balancing of the PACK by a second balancing module based on the second actual charge state includes:

[0026] When the difference between the second actual state of charge of a first target PACK and the second actual state of charge of a lowest PACK in the at least one PACK is greater than a fourth preset value, adjusting the second balancing module to balance the state of charge of the first target PACK; wherein the lowest PACK is the PACK with the lowest second actual state of charge in the at least one PACK.

[0027] According to one embodiment of the present application, the second balancing module includes a fourth resistor and a fourth switch connected in series, and the fourth resistor and the fourth switch connected in series are connected in parallel with the PACK;

[0028] The adjusting the second balancing module to balance the state of charge of the first target PACK includes:

[0029] controlling a fourth switch corresponding to the first target PACK to be closed;

[0030] After a first target time period, the fourth switch corresponding to the first target PACK is controlled to be disconnected.

[0031] According to one embodiment of the present application, the first target duration is determined based on the following steps:

[0032] The first target duration is calculated based on the second actual state of charge of the first target PACK, the second actual state of charge of the lowest PACK, the nominal capacity of the battery, the battery aging degree of the first target PACK, the voltage across the first target PACK, and the resistance value of the fourth resistor.

[0033] According to one embodiment of the present application, it further includes:

[0034] When the cell voltage of at least one battery cell in the first target PACK is lower than a sixth preset value, the branch including the fourth resistor and the fourth switch connected in series in parallel with the first target PACK is controlled to be disconnected.

[0035] According to one embodiment of the present application, it further includes:

[0036] When the actual temperature of the second balancing module is greater than a fifth preset value, a heat dissipation operation is performed on the second balancing module.

[0037] In a second aspect, the present application provides a balancing control device for a battery cluster, wherein the battery cluster includes at least one PACK, and the PACK includes at least one battery cell; the device includes:

[0038] a first processing module, configured to obtain at least one of a first actual state of charge and an actual state of health of each battery cell, and a second actual state of charge of each pack;

[0039] a second processing module, configured to control at least one of state of charge balancing and health state balancing of the battery cells through a first balancing module based on at least one of the first actual state of charge and the actual health state;

[0040] a third processing module, configured to control the charge state balancing of the PACK through a second balancing module based on the second actual charge state;

[0041] The first balancing module and the second balancing module are connected to the PACK respectively.

[0042] According to the balancing control device for a battery cluster of the present application, by distinguishing different balancing purposes, a first balancing module for balancing differences between battery cells and a second balancing module for balancing differences between packs are respectively provided. While reducing system cost and complexity, it can effectively ensure the normal and efficient operation of the battery cluster and has high reliability.

[0043] In a third aspect, the present application provides a system based on the battery cluster balancing control method according to the first aspect, comprising:

[0044] Battery Management Unit;

[0045] A first balancing module is connected to the battery management unit and the PACK respectively;

[0046] The second balancing module is connected to the battery management unit and the PACK respectively.

[0047] In a fourth aspect, the present application provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the battery cluster balancing control method as described in the first aspect above is implemented.

[0048] In a fifth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the battery cluster balancing control method as described in the first aspect above.

[0049] In a sixth aspect, the present application further provides an energy storage system adjustment method for performing balanced control on the energy storage system, wherein the energy storage system includes at least two battery clusters, each battery cluster including at least one battery cell, and the method includes the following steps:

[0050] Determining whether the energy storage system is in a voltage plateau region or a voltage non-plateau region;

[0051] If the energy storage system is in the voltage plateau region, the maximum real-time SOC or the minimum real-time SOC of all battery clusters is used as the basis for determining whether balancing is required, and the battery cluster is used as the balancing object;

[0052] If the energy storage system is in a voltage non-platform region, the maximum cell voltage or the minimum cell voltage of all battery clusters is used as a basis for determining whether balancing is required, and the battery cluster is used as a balancing object.

[0053] According to one embodiment of the present application, an OCV-SOC curve of an energy storage system is obtained, and a voltage plateau region and a voltage non-plateau region are divided according to the slope of the OCV-SOC curve.

[0054] According to one embodiment of the present application, the endpoint values ​​of the voltage platform area are SOCtag1 and SOCtag2, 0<SOCtag1<SOCtag2<1, SOCtag1 is the starting point SOC value of the voltage platform area, and SOCtag2 is the ending point SOC value of the voltage platform area.

[0055] According to one embodiment of the present application, the aging status of the battery cells of the energy storage system is detected, the OCV-SOC curve of the energy storage system is updated according to the aging status of the battery cells, and the voltage platform area and the voltage non-platform area are divided according to the slope of the updated OCV-SOC curve.

[0056] According to one embodiment of the present application, the charge and discharge status of the energy storage system is obtained, and inter-cluster balancing adjustment of the energy storage system is performed according to the charge and discharge status of the energy storage system.

[0057] According to one embodiment of the present application, when the energy storage system is in the charging process, the maximum real-time SOC of all battery clusters, i.e., SOCmax, enters between SOCtag1 and SOCtag2, SOCtag1≤SOCmax≤SOCtag2, and the regulation current of each battery cluster is calculated by the following formula: I i =min{x i *I 总 , I i最大允许充电电流}

[0058] Among them, I i Indicates the target current value of each battery cluster, x i Represents the cluster current distribution weight coefficient of each battery cluster, I 总 Indicates the total current input to the energy storage system;

[0059] Cluster current distribution weight coefficient x i The calculation formula is as follows:

[0060] Among them, MaxSoc i Indicates the maximum real-time SOC of each cluster, Cap i Indicates the nominal capacity of each battery cluster at the current temperature.

[0061] According to one embodiment of the present application, the target current value I of each battery cluster is calculated. i The calculation formula is as follows:

[0062] in, is the total current input to the energy storage system at the current moment;

[0063] The calculation formula for the total current input to the energy storage system at the current moment is as follows:

[0064] in, It is the adjusted target current value of each battery cluster at the previous moment.

[0065] According to one embodiment of the present application, when the energy storage system is in the charging process, the maximum real-time SOC of all battery clusters, i.e., SOCmax, is greater than SOCtag2, SOCtag2<SOCmax<1, and the maximum cell voltage in each battery cluster is compared with the average value of the maximum cell voltage in all battery clusters. When the difference between the maximum cell voltage in a battery cluster and the average value of the maximum cell voltage in all battery clusters exceeds a preset voltage difference threshold, the current of the battery cluster is regulated.

[0066] According to one embodiment of the present application, when the difference between the maximum cell voltage in a battery cluster and the average value of the maximum cell voltages in all battery clusters exceeds a preset voltage difference threshold, during the current regulation of the battery cluster, the regulation current of the battery cluster is calculated using the following formula:

[0067] Among them, MaxVolt i Indicates the maximum cell voltage of each battery cluster, i indicates the number of battery clusters, MaxVolt avg Indicates the average voltage of the maximum cell voltage of all battery clusters, Indicates the current amount that needs to be adjusted in the current cycle, K p Represents the proportional adjustment coefficient, K i Indicates the integral adjustment coefficient, K d represents the differential adjustment coefficient, Indicates the target current value of the previous cycle, Indicates the target current value of the current cycle.

[0068] According to one embodiment of the present application, the current amount to be adjusted during the current cycle When calculating , remove the integral adjustment item when one of the following conditions occurs

[0069] The maximum cell voltage of the battery cluster being adjusted is lower than the sum of the average voltage of the maximum voltages of all battery clusters and a preset voltage difference threshold;

[0070] Current working state switching;

[0071] conduct The calculation integration time exceeds the preset adjustment step;

[0072] The actual current value of the current cycle and the target current value of the previous cycle The difference is outside the preset range.

[0073] According to one embodiment of the present application, when the energy storage system is in the discharge process, the minimum real-time SOC of all battery clusters, i.e., SOCmin, falls between SOCtag1 and SOCtag2, and SOCtag1 ≤ SOCmin ≤ SOCtag2. Then, the regulation current of each battery cluster is calculated by the following formula:

[0074] Among them, I i Indicates the target current value of each battery cluster, x i Represents the cluster current distribution weight coefficient of each battery cluster, I 总 Indicates the total current output by the energy storage system to the external load;

[0075] Cluster current distribution weight coefficient x i The calculation formula is as follows:

[0076] Among them, MinSoc i Indicates the minimum real-time SOC of each cluster, Cap i Indicates the nominal capacity of each battery cluster at the current temperature.

[0077] According to one embodiment of the present application, the target current value I of each battery cluster is calculated. i The calculation formula is as follows:

[0078] in, The total current output from the energy storage system to the external load at the current moment;

[0079] The calculation formula for the total current input to the energy storage system at the current moment is as follows:

[0080] in, It is the adjusted target current value of each battery cluster at the previous moment.

[0081] According to one embodiment of the present application, when the energy storage system is in the discharge process, the minimum real-time SOC of all battery clusters, i.e., SOCmin, is less than SOCtag1, 0<SOCmin<SOCtag1, and the minimum cell voltage in each battery cluster is compared with the average value of the minimum cell voltage in all battery clusters. When the difference between the minimum cell voltage in a battery cluster and the average value of the minimum cell voltage in all battery clusters exceeds a preset voltage difference threshold, the current of the battery cluster is regulated.

[0082] According to one embodiment of the present application, when the difference between the minimum cell voltage in a battery cluster and the average value of the minimum cell voltages in all battery clusters exceeds a preset voltage difference threshold, during the current regulation of the battery cluster, the regulation current of the battery cluster is calculated using the following formula:

[0083] Among them, MinVolt i Indicates the minimum cell voltage of each battery cluster, i indicates the number of battery clusters, MinVolt avg Indicates the average voltage of the minimum cell voltage of all battery clusters, Indicates the current amount that needs to be adjusted in the current cycle, K p Represents the proportional adjustment coefficient, K i Indicates the integral adjustment coefficient, K d represents the differential adjustment coefficient, Indicates the target current value of the previous cycle, Indicates the target current value of the current cycle.

[0084] According to one embodiment of the present application, the current amount to be adjusted during the current cycle When calculating the integral adjustment term, if one of the following conditions occurs, remove the integral adjustment term.

[0085] The minimum cell voltage of the battery cluster to be adjusted is higher than the difference between the average voltage of the minimum voltages of all battery clusters and a preset voltage difference threshold;

[0086] Current working state switching;

[0087] conduct The calculation integration time exceeds the preset adjustment step;

[0088] The actual current value of the current cycle and the target current value of the previous cycle The difference is outside the preset range.

[0089] In a seventh aspect, the present application also provides a computer medium executed by a data processing device, wherein the data processing device has a processor containing program code, and when executing the program code, the processor executes the aforementioned energy storage battery balancing control method.

[0090] In an eighth aspect, the present application further provides an energy storage system, which includes a battery management unit and at least two battery clusters, wherein the battery management unit is configured to execute the aforementioned energy storage system adjustment method to perform balanced adjustment on the battery clusters in the energy storage system.

[0091] In a ninth aspect, the present application further provides a power generation system, which includes an energy storage system and a central control unit, wherein the central control unit is configured to execute the energy storage system adjustment method as described above to perform balancing adjustment on the battery clusters in the energy storage system.

[0092] In a tenth aspect, the present application further provides a method for controlling current sharing of energy storage batteries, which is used to control current sharing of multiple battery packs, where the battery packs are connected in parallel to form a battery pack, and the method comprises the following steps:

[0093] Step S1: Read the capacity Ci, battery health status parameter SOHi, and battery charge status parameter SOCi of each battery pack i;

[0094] Step S3: determining the discharge current Current (sys) required by the electrical load connected to the battery pack;

[0095] Step S5: Calculate the desired output current Current(i) of each battery pack based on the capacity Ci of battery pack i, the battery health status parameter SOHi, the battery charge status parameter SOCi, and the discharge current Current(sys) required by the load connected to the battery pack. The specific calculation formula is as follows:

[0096] Step S7: controlling the output current of each battery pack according to the calculated simulated output current Current(i) of each battery pack.

[0097] According to one embodiment of the present application, in step S1, the internal temperature Ti of each battery pack is collected and a temperature threshold coefficient Tavg is configured. After the calculation of the intended output current Current(i) of each battery pack is completed, a secondary adjustment is made based on the internal temperature Ti of the battery pack and the temperature threshold coefficient Tavg to form the output control current Current'(i).

[0098] According to one embodiment of the present application, the internal temperature changes of each battery pack are monitored, and when the temperature change value of a battery pack is not less than the temperature difference threshold t, the output current of the battery pack is calculated and adjusted.

[0099] According to one embodiment of the present application, the maximum value Tmax and the minimum value Tmin of the internal temperature of the battery pack collected during the monitoring process are read, and the temperature change value of the battery pack is Tmax-Tmin.

[0100] According to one embodiment of the present application, the temperature difference threshold t is 2 to 10°C.

[0101] According to one embodiment of the present application, in the process of secondary adjustment to form the output control current Current'(i) according to the internal temperature Ti of the battery pack and the temperature threshold coefficient Tavg, the calculation formula of the output control current Current'(i) is as follows:

[0102] The temperature threshold coefficient Tavg is the average temperature of each battery pack, that is,

[0103] According to one embodiment of the present application, in step S7, the output current of each battery pack is controlled by adjusting the resistance inside the battery pack, or by adjusting the output voltage of the battery pack.

[0104] According to one embodiment of the present application, the output voltage of the battery pack is adjusted by performing voltage conversion inside each battery pack.

[0105] According to one embodiment of the present application, in step S1, the real-time capacity Qi and the maximum allowable output power Pi of each battery pack i are also read;

[0106] In step S3, the power P(sys) required by the electrical load connected to the battery pack must also be determined;

[0107] The method also includes step S4, comparing the real-time capacity Qi of each battery pack i, discharging the battery pack with the largest real-time capacity first while meeting the power demand of the power load, and calculating and determining the intended output current Current(i) of each battery pack after the real-time capacity of each battery pack is balanced.

[0108] According to one embodiment of the present application, in step S4, each battery pack is arranged in descending order according to its real-time capacity, and the battery packs are controlled to output current in sequence at a state not higher than the maximum allowable output power in the arranged order until the total output power reaches the power P(sys) required by the electrical load.

[0109] In the eleventh aspect, the present application also provides a computer medium executed by a data processing device, wherein the data processing device has a processor containing program code, and when executing the program code, the processor executes the aforementioned energy storage battery current sharing control method.

[0110] In the twelfth aspect, the present application also provides an energy storage battery current sharing control system, wherein the energy storage battery includes multiple groups of battery packs connected in parallel, which are connected to an energy storage inverter after being connected in parallel, and the output end of the energy storage inverter is connected to the electrical load for supplying power to the electrical load. A DC conversion module is provided in each battery pack, and the output end of the battery pack is connected to the DC conversion module, which is then connected to the energy storage inverter. The energy storage inverter determines the intended output current Current(i) according to the energy storage battery current sharing control method as described above, and controls the output voltage of the DC conversion module according to the intended output current Current(i).

[0111] In the thirteenth aspect, the present application also provides a current sharing control system for an energy storage battery, wherein the energy storage battery includes multiple groups of battery packs connected in parallel, which are connected to an energy storage inverter after being connected in parallel, and the output end of the energy storage inverter is connected to the electrical load for supplying power to the electrical load. A DC conversion module and a temperature sensor are respectively provided in each battery pack, and the output end of the battery pack is connected to the DC conversion module, which is then connected to the energy storage inverter. The data output end of the temperature sensor is connected to the DC conversion module in the battery pack, and the energy storage inverter determines the output current Current'(i) according to the energy storage battery current sharing control method as described above, and controls the output voltage of the DC conversion module according to the simulated output current Current(i). BRIEF DESCRIPTION OF THE DRAWINGS

[0112] FIG1 is a flow chart of a method for controlling a battery cluster balance according to an embodiment of the present application;

[0113] FIG2 is a second flow chart of a method for controlling a battery cluster balance according to an embodiment of the present application;

[0114] FIG3 is a third flow chart of a method for controlling a battery cluster balance according to an embodiment of the present application;

[0115] FIG4 is a fourth flow chart of a method for controlling a battery cluster balance according to an embodiment of the present application;

[0116] FIG5 is a schematic diagram of a structure of a system based on a battery cluster balancing control method according to an embodiment of the present application;

[0117] FIG6 is a second structural diagram of a system based on a battery cluster balancing control method according to an embodiment of the present application;

[0118] FIG7 is a third structural diagram of a system for a battery cluster balancing control method according to an embodiment of the present application;

[0119] FIG8 is a fourth structural diagram of a system for a battery cluster balancing control method according to an embodiment of the present application;

[0120] FIG9 is a fifth structural diagram of a system for a battery cluster balancing control method according to an embodiment of the present application;

[0121] FIG10 is a schematic structural diagram of a battery cluster balancing control device according to an embodiment of the present application;

[0122] FIG11 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0123] FIG12 is an OCV-SOC curve of an energy storage system according to one embodiment of the present application;

[0124] FIG13 is a schematic diagram of a process for confirming a voltage platform region and endpoint values ​​of an energy storage system according to one embodiment of the present application;

[0125] FIG14 is a schematic diagram of an energy storage system adjustment method according to one embodiment of the present application;

[0126] FIG15 is a schematic diagram of a method for adjusting an energy storage system in a charging state according to another embodiment of the present application;

[0127] FIG16 is a schematic diagram of a method for adjusting an energy storage system in a charging state according to yet another embodiment of the present application;

[0128] FIG17 is a schematic diagram of a method for adjusting an energy storage system in a discharge state according to another embodiment of the present application;

[0129] FIG18 is a schematic diagram of a method for adjusting an energy storage system in a discharge state according to yet another embodiment of the present application;

[0130] FIG19 is a schematic diagram of the working process of a method for controlling current sharing of energy storage batteries according to an embodiment of the present application;

[0131] FIG20 is a schematic diagram of the working process of a method for controlling current sharing of energy storage batteries according to another embodiment of the present application;

[0132] FIG21 is a schematic diagram of the workflow of a method for controlling current sharing of energy storage batteries according to another embodiment of the present application;

[0133] FIG22 is a schematic diagram of the framework structure of an energy storage battery current sharing control system according to one embodiment of the present application;

[0134] FIG23 is a schematic diagram of the framework structure of an energy storage battery current sharing control system according to another embodiment of the present application. DETAILED DESCRIPTION

[0135] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.

[0136] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of this application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," and the like are generally of the same type, and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0137] The following describes in detail the battery cluster balancing control method, battery cluster balancing control device, electrical system and readable storage medium provided by the embodiments of the present application through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0138] The battery cluster balancing control method may be applied to a terminal, and may be specifically executed by hardware or software in the terminal.

[0139] The battery cluster balancing control method provided in the embodiments of the present application may be executed by an electronic device or a functional module or functional entity in the electronic device that is capable of implementing the battery cluster balancing control method. The electronic devices mentioned in the embodiments of the present application include but are not limited to mobile phones, tablet computers, computers, cameras, and wearable devices. The battery cluster balancing control method provided in the embodiments of the present application will be described below using the electronic device as an example of the execution entity.

[0140] As shown in FIG1 , the battery cluster balancing control method includes: step 110 , step 120 and step 130 .

[0141] The battery cluster includes at least one PACK, and the PACK includes at least one battery cell.

[0142] Step 110: Obtain at least one of a first actual state of charge and an actual state of health of each battery cell, and a second actual state of charge of each pack;

[0143] In this step, the actual state of charge (SOC) is the ratio of the remaining battery capacity to the battery capacity.

[0144] The state of health (SOH) is the percentage of the battery's current capacity to its factory capacity.

[0145] Step 120: Based on at least one of a first actual state of charge and an actual state of health, control at least one of state of charge balancing and state of health balancing of each battery cell through a first balancing module;

[0146] In this step, the first balancing module is used to control and regulate the battery cells.

[0147] The first balancing module is used to keep the actual charge state of each battery cell in the same PACK consistent, and / or to enable each battery cell in the same PACK to reach the scrap standard at the same time.

[0148] In actual execution, the number of battery cells to be subjected to state-of-charge balancing or health state balancing may be zero, one, or multiple, and the balancing processing corresponding to each battery cell is independent of each other.

[0149] When performing state of charge balancing, a passive balancing adjustment method may be used, such as performing passive resistance discharge on battery cells with higher first actual state of charge based on the first actual state of charge of each battery cell.

[0150] When balancing the health status, active balancing adjustment can be used to perform active energy transfer.

[0151] Step 130: Based on the second actual state of charge, control the charge state of the PACK through a second balancing module;

[0152] The first balancing module and the second balancing module are connected to the PACK respectively.

[0153] In this step, the second balancing module is used to control and adjust the PACK.

[0154] The second balancing module is used to keep the actual charge states of the PACKs in the same battery cluster consistent.

[0155] In actual implementation, the number of PACKs performing SOC balancing may be 0, one, or multiple, and the SOC balancing corresponding to each PACK is independent of each other.

[0156] In some embodiments, the second balancing module can use active energy transfer, passive resistance discharge, dynamic resistance, or a heat dissipation device corresponding to the PACK to balance the charge state of the PACK, so as to transfer energy to one or more PACKs with a higher second actual charge state.

[0157] It should be noted that step 120 and step 130 of the present application can be executed simultaneously without interfering with each other.

[0158] During the research and development process, the applicant discovered that in related technologies, a DC / DC optimizer is often configured for a single PACK to achieve PACK balancing. However, this method has low reliability and high cost, and also reduces the charging and discharging efficiency of the energy storage system.

[0159] In the present application, by distinguishing different balancing purposes, a first balancing module for balancing the differences between battery cells and a second balancing module for balancing the differences between PACKs are respectively provided. While reducing the system cost and complexity, the second balancing module can be used to balance the PACK when the PACK is installed and replaced, and the first balancing module can be used to balance the battery cells during daily operation, effectively ensuring the normal and efficient operation of the battery cluster with high reliability.

[0160] According to the battery cluster balancing control method provided in the embodiment of the present application, by distinguishing different balancing purposes, a first balancing module for balancing differences between battery cells and a second balancing module for balancing differences between packs are respectively provided. While reducing system cost and complexity, it can effectively ensure the normal and efficient operation of the battery cluster, improve the consistency of the batteries, thereby reducing the weak plate effect; and has high reliability.

[0161] The specific implementation methods of battery cell SOC balancing, battery cell SOH balancing, and PACK SOC balancing are described below.

[0162] 1. SOC balancing of battery cells

[0163] As shown in FIG5 , in some embodiments, the first balancing module includes a first sub-balancing module, namely, the first balancing module A shown in FIG5 .

[0164] As shown in FIG2 , step 120 may include:

[0165] When a difference between a first actual state of charge of a first target battery cell and a first actual state of charge of a first lowest battery cell among the at least one battery cell is greater than a first preset value, the first sub-balancing module is adjusted to balance the state of charge of the first target battery cell.

[0166] In this embodiment, one PACK corresponds to at least one first sub-balancing module, and the first sub-balancing module is used to perform SOC balancing on each battery cell in the same PACK.

[0167] The first sub-balancing module may be integrated into a battery management unit (BMU).

[0168] The first sub-balancing module may adopt a passive balancing circuit or an active balancing circuit.

[0169] The first target battery cell may be any battery cell among all the battery cells included in the same PACK.

[0170] The number of the first target battery cells may be one or more. When there are multiple first target battery cells, SOC balancing is performed independently between the first target battery cells, and the execution strategies are similar.

[0171] The first lowest cell is a cell having the lowest actual state of charge among all the cells in the same pack.

[0172] The difference can be a difference or a ratio, etc., which is not limited in this application.

[0173] The first preset value may be user-defined, or may be determined based on factors such as voltage sampling error, current sampling error, capacity difference of the single battery cells themselves, and SOC estimation error.

[0174] For example, when the SOC difference control target is 0.5%, the first preset value can be determined as 0.5%; that is, when the difference between the first actual state of charge of the first target battery cell and the first actual state of charge of the first lowest cell exceeds the first preset value, it is considered that the actual SOC of the first target battery cell is high and discharge balancing is required, and the first sub-balancing module is turned on to discharge the first target battery cell to reduce its actual SOC.

[0175] Of course, in other embodiments, the first preset value may also be set to other values, such as 0.6% or 0.4%, etc., which is not limited in this application.

[0176] The following describes the first sub-balancing module and its corresponding processing logic by taking a passive balancing circuit as an example.

[0177] As shown in FIG6 , in some embodiments, the first sub-balancing module includes at least one first switch connected in parallel with at least one battery cell in a one-to-one correspondence, and a first resistor disposed between the first switch and the battery cell connected in parallel with the first switch.

[0178] Wherein, C1, C2, ..., Cn are multiple battery cells included in a PACK, and n is a positive integer.

[0179] The first resistor may be disposed between the positive electrode of the battery cell and the first switch; or between the negative electrode of the battery cell and the first switch; or between the positive electrode of the battery cell and the first switch and between the negative electrode of the battery cell and the first switch.

[0180] The resistance values ​​of the first resistors are the same.

[0181] When the first switch is closed, the branch where the first switch is located is turned on, the battery cell corresponding to the first switch forms a path with the first switch and the first resistor, and the battery cell starts to discharge.

[0182] Continuing with FIG2 , adjusting the first sub-balancing module to perform state of charge balancing on the first target battery cell may include:

[0183] controlling a first switch connected in parallel with the first target battery cell to be closed;

[0184] When the difference between the first actual state of charge of the first target battery cell and the first actual state of charge of the first lowest cell is less than a second preset value, the first switch connected in parallel with the first target battery cell is controlled to be disconnected, and the second preset value is less than the first preset value.

[0185] In this embodiment, the second preset value should be smaller than the first preset value to avoid repeated opening and closing of the first switch corresponding to the corresponding battery cell due to jitter.

[0186] The second preset value may be based on user customization, or may be determined based on an SOC difference control target.

[0187] Continuing to take the SOC difference control target of 0.5% as an example, based on the control target and the hysteresis value of 0.2%, the second preset value may be set to 0.5%-0.2%=0.3%.

[0188] Of course, in other embodiments, the second preset value may also be set to other values, such as 0.2% or 0.4%, etc., which is not limited in this application.

[0189] For example, when CellSocn-MinCellSoc>A1, the BMU controls the circuit corresponding to the first sub-balancing module to balance the n-th battery cell Cn, that is, closes the first switch Sn; wherein CellSocn is the first actual state of charge of the n-th battery cell; MinCellSoc is the first actual state of charge of the first lowest cell; A1 is the first preset value; Sn is the first switch set in parallel with the n-th battery cell, and n is a positive integer.

[0190] While balancing the n-th battery cell Cn, the first actual state of charge corresponding thereto is collected in real time and compared with the second preset value.

[0191] In the case of CellSocn-MinCellSoc>A2, the BMU controls the circuit corresponding to the first sub-balancing module to stop balancing the n-th battery cell Cn, that is, to turn off the first switch Sn; wherein A2 is a second preset value.

[0192] According to the battery cluster balancing control method provided in the embodiment of the present application, by configuring a passive balancing circuit to balance the SOC of the battery cells, the circuit complexity and design cost can be reduced. In addition, by setting a second preset value lower than the first preset value to control the end of the SOC balancing of the battery cells, it is possible to avoid jitter causing the first switch corresponding to the corresponding battery cell to be repeatedly turned on and off, thereby improving the stability of the first sub-balancing module and further improving the stability and reliability of the energy storage system.

[0193] 2. SOH balance of battery cells

[0194] 5 , in some embodiments, the first balancing module may include a second sub-balancing module, ie, the first balancing module B shown in FIG. 5 .

[0195] As shown in FIG3 , step 120 may include:

[0196] When the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is greater than a third preset value, the second sub-balancing module is adjusted to balance the health state of the second lowest cell.

[0197] In this embodiment, one PACK corresponds to at least one second sub-balancing module, and the second sub-balancing module is used to perform SOH balancing on each battery cell in the same PACK.

[0198] In some embodiments, the second sub-balancing module may be integrated into the BMU.

[0199] In some embodiments, the second sub-balancing module may also be independently provided and connected to the BMU via a board-side connector or a flat cable.

[0200] The first highest cell is the cell with the highest actual health state among all the battery cells included in the same PACK, and the second lowest cell is the cell with the lowest actual health state among all the battery cells included in the same PACK.

[0201] The difference can be a difference or a ratio, etc., which is not limited in this application.

[0202] The third preset value may be user-defined or determined based on a PACK SOH estimation error.

[0203] The second sub-balancing module may adopt an active balancing circuit.

[0204] The second sub-balancing module may be a bidirectional or unidirectional DC / DC, and is used for energy transfer between the second lowest cell and the PACK where the second lowest cell is located.

[0205] During the actual execution process, the battery cells with the highest and lowest actual health status in the PACK can be obtained in real time, and the SOH difference between the highest battery cell and the lowest battery cell can be compared.

[0206] In a case where the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is not greater than a third preset value, SOH equalization may not be performed.

[0207] When the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is greater than a third preset value, the second sub-balancing module may be enabled to perform SOH balancing on the second lowest cell.

[0208] For example, when MaxCellSoh - MinCellSoh > Q1, the BMU controls the balancing circuit of the second sub-balancing module to balance the second lowest cell SOH and the corresponding battery cell where the second lowest cell SOH is located in turn; wherein MaxCellSoh is the actual health status of the first highest cell; MinCellSoh is the actual health status of the second lowest cell; and Q1 is a third preset value.

[0209] It should be noted that the first sub-balancing module and the second sub-balancing module work independently of each other and do not affect each other.

[0210] The balancing function of the second sub-balancing module works continuously when the battery system is running and stops when the system is in standby mode.

[0211] The second sub-balancing module and its corresponding control logic are described below using a flyback DC / DC circuit as an example.

[0212] As shown in FIG7 , in some embodiments, the second sub-balancing module includes at least one electromagnetic induction module arranged in a one-to-one correspondence with at least one battery cell, a first end of the electromagnetic induction module is connected to the positive electrode of the battery cell, a second end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a second resistor and a second switch connected in series, a third end of the electromagnetic induction module is connected to the positive electrode of the battery cell, and a fourth end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a third resistor and a third switch connected in series.

[0213] Wherein, when the second switch and the third switch corresponding to the electromagnetic induction module are closed, the entire PACK charges the battery cell corresponding to the electromagnetic induction module.

[0214] As shown in FIG3 , adjusting the second sub-balancing module to balance the health status of the second lowest cell may include:

[0215] The second switch and the third switch corresponding to the second lowest cell are controlled to be closed in sequence.

[0216] In this embodiment, for example, when MaxCellSoh-MinCellSoh>Q1, the microprocessor of the current PACK sequentially controls the second switch Sn1 and the third switch Sn2 corresponding to the second lowest cell Cn to close, and realizes energy transfer through magnetization and demagnetization of the secondary and primary inductors.

[0217] According to the battery cluster balancing control method provided in the embodiment of the present application, an independently working active balancing circuit is set to balance the SOH of the battery cells. Based on a two-stage balancing module and equipped with active and passive balancing functions as well as increase and decrease functions, it is possible to balance the initial investment of the system, reduce the battery balancing requirements in the middle and late stages of system operation, and effectively improve the reliability of the battery balancing circuit, achieve PACK balancing, and thus improve the reliability of the energy storage system.

[0218] 3. PACK SOC balance

[0219] As shown in FIG4 , in some embodiments, step 130 may include:

[0220] When a difference between the second actual state of charge of the first target PACK and the second actual state of charge of the lowest PACK in the at least one PACK is greater than a fourth preset value, the second balancing module is adjusted to balance the state of charge of the first target PACK.

[0221] In this embodiment, the first target PACK may be any PACK among all PACKs included in the battery cluster.

[0222] The difference can be a difference or a ratio, etc., which is not limited in this application.

[0223] The fourth preset value may be user-defined or determined based on a PACK SOC estimation error.

[0224] In actual implementation, each PACK corresponds to a second balancing module, and the second balancing module performs SOC balancing on a single PACK.

[0225] The lowest PACK is the PACK with the second lowest actual state of charge among all the PACKs included in the battery cluster.

[0226] When PackSocn-MinPackSoc>B1, the BMU controls the second balancing module to balance the nth PACK; wherein PackSocn is the second actual state of charge of the nth PACK; MinPackSoc is the second actual state of charge of the lowest PACK; B1 is a fourth preset value; and n is a positive integer.

[0227] According to the battery cluster balancing control method provided in the embodiment of the present application, by setting a second balancing module to balance the SOC of a single PACK, combined with the first balancing module, it is possible to achieve secondary SOC balancing control corresponding to the battery cells and the PACK, solving the technical problem of manual intervention and adjustment required when mixing PACKs with different SOC states into a battery cluster, thereby improving the reliability of the energy storage system.

[0228] As shown in FIG. 9 , in some embodiments, the second balancing module includes a fourth resistor and a fourth switch connected in series, and the fourth resistor and the fourth switch connected in series are connected in parallel with the PACK.

[0229] The fourth resistor is a balancing resistor.

[0230] When the fourth switch is closed, a path is formed between the PACK, the fourth resistor, and the fourth switch, and the PACK is discharged.

[0231] Continuing with FIG4 , adjusting the second balancing module to balance the state of charge of the first target PACK may include:

[0232] controlling the fourth switch corresponding to the first target PACK to be closed;

[0233] After the first target time period, the fourth switch corresponding to the first target PACK is controlled to be turned off.

[0234] In this embodiment, the first target duration is the total duration of controlling the fourth switch to be closed.

[0235] The first target duration may be user-defined or obtained through calculation.

[0236] In some embodiments, the first target duration is determined based on the following steps:

[0237] The first target duration is calculated based on the second actual state of charge of the first target PACK, the second actual state of charge of the lowest PACK, the nominal capacity of the battery, the battery aging degree of the first target PACK, the voltage across the first target PACK, and the resistance value of the fourth resistor.

[0238] In this embodiment, the first target duration can be determined by the following formula: T_1 = ((SOC_Pn-SOC_Pmin-B_1)×Q×〖SOH〗_p) / II=V_P / R

[0239] Among them, T_1 is the first target duration; SOC_Pn is the second actual state of charge of the nth PACK; SOC_Pmin is the second actual state of charge of the lowest PACK; B_1 is the fourth preset value; Q is the nominal capacity of the battery; [SOH]_p is the battery aging degree of the first target PACK; V_P is the voltage value across the first target PACK; R is the resistance value of the fourth resistor.

[0240] In actual implementation, for example, when PackSocn-MinPackSoc>B1, the fourth switch S02 corresponding to the nth PACK is closed to balance the SOC of the PACKs in a passive resistance discharge manner.

[0241] After the balancing duration of the PACK reaches the first target duration, the fourth switch S02 corresponding to the nth PACK may be controlled to be turned off to end the balancing.

[0242] In some embodiments, when the first target PACK includes multiple PACKs, the fourth switch corresponding to each PACK may be controlled to be closed respectively, so as to perform SOC balancing on the multiple PACKs respectively.

[0243] According to the battery cluster balancing control method provided in the embodiment of the present application, the SOC balancing of a single PACK is performed through a passive balancing module, which can solve the PACK-level balancing problem without adding a DC / DC optimizer, and further improve the reliability of the energy storage system.

[0244] In some embodiments, the method may further include:

[0245] When the cell voltage of at least one battery cell in the first target PACK is lower than a sixth preset value, the branch including the fourth resistor and the fourth switch connected in series in parallel with the first target PACK is controlled to be disconnected.

[0246] In this embodiment, the sixth preset value is the lowest voltage value corresponding to the battery cell.

[0247] When the cell voltage of a battery cell is lower than the minimum voltage value, it can be approximately considered that the battery cell is under-voltage.

[0248] In actual implementation, the cell voltage of each battery cell can be collected in real time. When the cell voltage is less than the sixth preset value V1, the fourth switch is controlled to be disconnected to stop SOC balancing to avoid battery undervoltage fault.

[0249] Continuing with reference to FIG9 , in some embodiments, the second balancing module may further include a fifth switch S01 connected in series with the fourth switch S02 . Under normal circumstances, the fifth switch S01 may be set to a closed state by default. When the cell voltage is less than a sixth preset value, the fifth switch S01 is controlled to be disconnected to stop SOC balancing.

[0250] According to the battery cluster balancing control method provided in the embodiment of the present application, by real-time monitoring of the cell voltage of each battery cell, the SOC balancing of the pack is stopped when the cell voltage is low, thereby effectively avoiding battery undervoltage failure and improving the stability and reliability of the energy storage system.

[0251] Continuing with reference to FIG4 , in some embodiments, the method may further include:

[0252] When the actual temperature of the second balancing module is greater than a fifth preset value, a heat dissipation operation is performed on the second balancing module.

[0253] In this embodiment, the fifth preset value is used to limit the temperature of the second balancing module to a more appropriate temperature range.

[0254] The fifth preset value may be user-defined or determined based on experimental data, which is not limited in this application.

[0255] During actual implementation, a temperature sensor may be provided in the second balancing module to collect the actual temperature of the second balancing module and compare the actual temperature with the fifth preset value in real time.

[0256] When the actual temperature is not greater than the fifth preset value, the heat dissipation operation may not be performed on the second balancing module.

[0257] When the actual temperature is greater than the fifth preset value, a heat dissipation device such as a heat dissipation fan disposed in the second balancing module is turned on to dissipate heat from the second balancing module to reduce the temperature of the second balancing module.

[0258] In some embodiments, the cooling fan can also be used for energy transfer during the PACK SOC balancing process.

[0259] According to the battery cluster balancing control method provided in the embodiment of the present application, by monitoring the actual temperature of the second balancing module and performing a heat dissipation operation when the actual temperature of the second balancing module is high, the reliability of the energy storage system can be further improved and the service life can be extended.

[0260] In some embodiments, the method may further include:

[0261] The second balancing module is controlled based on the operating mode corresponding to the battery cluster.

[0262] In this embodiment, the working modes may include: operation and maintenance mode, online operation mode and cloud control mode.

[0263] Among them, the operation and maintenance mode works in the initial installation stage and SOC leveling is required.

[0264] In online operation mode, real-time control can be performed during battery system operation.

[0265] In cloud control mode, control can be based on big data control or manual background control.

[0266] During actual execution, the second balancing module may be controlled based on the set working mode.

[0267] The battery cluster balancing control method provided in the embodiment of the present application can be executed by a battery cluster balancing control device. In the embodiment of the present application, the battery cluster balancing control method performed by the battery cluster balancing control device is used as an example to illustrate the battery cluster balancing control device provided in the embodiment of the present application.

[0268] An embodiment of the present application further provides a battery cluster balancing control device.

[0269] The battery cluster includes at least one PACK, and the PACK includes at least one battery cell.

[0270] As shown in FIG10 , the battery cluster balancing control device includes a first processing module 1010 , a second processing module 1020 and a third processing module 1030 .

[0271] A first processing module 1010 is configured to obtain at least one of a first actual state of charge and an actual state of health of each battery cell, and a second actual state of charge of each pack;

[0272] a second processing module 1020, configured to control at least one of state of charge balancing and state of health balancing of each battery cell through a first balancing module based on at least one of a first actual state of charge and an actual state of health;

[0273] A third processing module 1030 is configured to control the charge state balancing of the PACK through a second balancing module based on the second actual charge state;

[0274] The first balancing module and the second balancing module are connected to the PACK respectively.

[0275] According to the battery cluster balancing control device provided in the embodiment of the present application, by distinguishing different balancing purposes, a first balancing module for balancing differences between battery cells and a second balancing module for balancing differences between packs are respectively provided. While reducing system cost and complexity, it can effectively ensure the normal and efficient operation of the battery cluster and has high reliability.

[0276] In some embodiments, the first balancing module includes a first sub-balancing module and a second processing module 1020, and may further be configured to:

[0277] When the difference between the first actual state of charge of a first target battery cell and the first actual state of charge of a first lowest battery cell in at least one battery cell is greater than a first preset value, the first sub-balancing module is adjusted to balance the state of charge of the first target battery cell; wherein the first lowest battery cell is the battery cell with the lowest first actual state of charge among the at least one battery cell.

[0278] In some embodiments, the first sub-balancing module includes at least one first switch connected in parallel with at least one battery cell in a one-to-one correspondence, and a first resistor provided between the first switch and the battery cell connected in parallel with the first switch;

[0279] The second processing module 1020 may also be used to:

[0280] controlling a first switch connected in parallel with the first target battery cell to be closed;

[0281] When the difference between the first actual state of charge of the first target battery cell and the first actual state of charge of the first lowest cell is less than a second preset value, the first switch connected in parallel with the first target battery cell is controlled to be disconnected, and the second preset value is less than the first preset value.

[0282] In some embodiments, the first balancing module includes a second sub-balancing module, the second processing module 1020, which may also be configured to:

[0283] When the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is greater than a third preset value, the second sub-balancing module is adjusted to balance the health state of the second lowest cell; wherein the first highest cell is the battery cell with the highest actual health state among the at least one battery cell, and the second lowest cell is the battery cell with the lowest actual health state among the at least one battery cell.

[0284] In some embodiments, the second sub-balancing module includes at least one electromagnetic induction module provided in one-to-one correspondence with at least one battery cell, a first end of the electromagnetic induction module is connected to the positive electrode of the battery cell, a second end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a second resistor and a second switch connected in series, a third end of the electromagnetic induction module is connected to the positive electrode of the battery cell, and a fourth end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a third resistor and a third switch connected in series;

[0285] The second processing module 1020 may also be used to:

[0286] The second switch and the third switch corresponding to the second lowest cell are controlled to be closed in sequence.

[0287] In some embodiments, the third processing module 1030 may also be used to:

[0288] When the difference between the second actual state of charge of a first target PACK and the second actual state of charge of a lowest PACK in at least one PACK is greater than a fourth preset value, the second balancing module is adjusted to balance the state of charge of the first target PACK; wherein the lowest PACK is the PACK with the lowest second actual state of charge in the at least one PACK.

[0289] In some embodiments, the second balancing module includes a fourth resistor and a fourth switch connected in series, and the fourth resistor and the fourth switch connected in series are connected in parallel with the PACK;

[0290] The third processing module 1030 may also be used to:

[0291] controlling the fourth switch corresponding to the first target PACK to be closed;

[0292] After the first target time period, the fourth switch corresponding to the first target PACK is controlled to be turned off.

[0293] In some embodiments, the apparatus may further include a fourth processing module configured to:

[0294] The first target duration is calculated based on the second actual state of charge of the first target PACK, the second actual state of charge of the lowest PACK, the nominal capacity of the battery, the battery aging degree of the first target PACK, the voltage across the first target PACK, and the resistance value of the fourth resistor.

[0295] In some embodiments, the apparatus may further include a fifth processing module configured to:

[0296] When the cell voltage of at least one battery cell in the first target PACK is lower than a sixth preset value, the branch including the fourth resistor and the fourth switch connected in series in parallel with the first target PACK is controlled to be disconnected.

[0297] In some embodiments, the apparatus may further include a sixth processing module configured to:

[0298] When the actual temperature of the second balancing module is greater than a fifth preset value, a heat dissipation operation is performed on the second balancing module.

[0299] The battery cluster balancing control device in the embodiments of the present application can be an electronic device or a component of an electronic device, such as an integrated circuit or chip. The electronic device can be a terminal or other device other than a terminal. For example, the electronic device can be a mobile phone, a tablet computer, a laptop computer, a PDA, an in-vehicle electronic device, a mobile internet device (MID), an augmented reality (AR) / virtual reality (VR) device, a robot, a wearable device, an ultra-mobile personal computer (UMPC), a netbook, or a personal digital assistant (PDA). It can also be a server, a network attached storage (NAS), a personal computer (PC), a television (TV), a teller machine (ATM), or a self-service machine, etc., and the embodiments of the present application do not specifically limit this.

[0300] The battery cluster balancing control device in the embodiment of the present application may be a device having an operating system, which may be an Android operating system, an iOS operating system, or other possible operating systems, which are not specifically limited in the embodiment of the present application.

[0301] The battery cluster balancing control device provided in the embodiment of the present application can implement each process implemented in the method embodiments of Figures 1 to 4 , and will not be described again here to avoid repetition.

[0302] As shown in FIG5 , an embodiment of the present application further provides a system based on the balancing control method of a battery cluster as described in any of the above embodiments, comprising: a battery management unit, a first balancing module and a second balancing module.

[0303] In this embodiment, the first balancing module is connected to the battery management unit and the PACK respectively, and the battery management unit controls the first balancing module to perform SOC balancing and / or SOH balancing on the single cells in the PACK.

[0304] The second balancing module is connected to the battery management unit and the PACK respectively, and the battery management unit controls the second balancing module to balance the SOC of the PACK.

[0305] The specific control logic has been described in the above embodiments and will not be repeated here in this application.

[0306] According to the system provided in the embodiment of the present application, by distinguishing different balancing purposes, a first balancing module for balancing differences between battery cells and a second balancing module for balancing differences between packs are respectively provided. While reducing system cost and complexity, it can effectively ensure the normal and efficient operation of the battery cluster and has high reliability.

[0307] 5 , in some embodiments, the first balancing module includes at least one of a first sub-balancing module A and a second sub-balancing module B.

[0308] In this embodiment, the first sub-balancing module A may adopt a passive balancing circuit to achieve the SOC balancing function of the battery cells.

[0309] The first sub-balancing module A may be integrated into the battery management unit.

[0310] The second sub-balancing module B may adopt an active balancing circuit to realize the SOH balancing function of the battery cells.

[0311] The second sub-equalizing module B is an independent part and can be integrated into the PACK or be arranged outside the system.

[0312] As shown in FIG8 , in some embodiments, the second sub-balancing module B and the BMU may be directly connected via a board connector or a cable, and the BMU and the second sub-balancing module B may communicate via a serial port or a CAN interface.

[0313] In some embodiments, the battery system can operate using only the BMU including the first sub-balancing module A.

[0314] In some embodiments, the second sub-balancing module B can be installed in the PACK before leaving the factory, or can be added during the subsequent operation and maintenance of the battery system. This application does not limit this.

[0315] According to the system provided in the embodiment of the present application, the flexibility of application can be improved by connecting the active balancing part to the battery system in an extended form.

[0316] As shown in FIG6 , in some embodiments, the first sub-balancing module A includes at least one first switch Sn (n=1, 2, ..., n) connected in parallel with at least one battery cell in a one-to-one correspondence, and a first resistor arranged between the first switch and the battery cell connected in parallel with the first switch.

[0317] The first resistor may be disposed between the positive electrode of the battery cell and the first switch; or between the negative electrode of the battery cell and the first switch; or between the positive electrode of the battery cell and the first switch and between the negative electrode of the battery cell and the first switch.

[0318] As shown in FIG7 , in some embodiments, the second sub-balancing module B includes at least one electromagnetic induction module arranged in a one-to-one correspondence with at least one battery cell, a first end of the electromagnetic induction module is connected to the positive electrode of the battery cell, a second end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a second resistor Rn1 (n=1, 2, ..., n) and a second switch Sn1 (n=1, 2, ..., n) connected in series, a third end of the electromagnetic induction module is connected to the positive electrode of the battery cell, and a fourth end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a third resistor Rn2 (n=1, 2, ..., n) and a third switch Sn2 (n=1, 2, ..., n) connected in series.

[0319] As shown in FIG. 9 , in some embodiments, the second balancing module includes a fourth resistor and a fourth switch S02 connected in series, and the fourth resistor and the fourth switch S02 connected in series are connected in parallel with the PACK.

[0320] The fourth resistor is a balancing resistor.

[0321] 9 , in some embodiments, the second balancing module may include a fourth resistor and a fourth switch S02 connected in series, and the fourth resistor and the fourth switch S02 connected in series are connected in parallel with the PACK. The second balancing module may further include: a fifth switch S01 and a voltage protection circuit.

[0322] In this embodiment, the fifth switch S01 is connected in series with the fourth switch S02.

[0323] The voltage protection circuit is electrically connected to the PACK and the fifth switch S01 respectively, and is used to control the on / off state of the fifth switch S01 based on the cell voltage of each battery cell in the PACK.

[0324] For example, when the cell voltage is less than the sixth preset value, the voltage protection circuit controls the fifth switch S01 to be disconnected to stop SOC balancing, thereby avoiding undervoltage faults in the battery and improving the stability and reliability of the energy storage system.

[0325] Continuing to refer to FIG. 9 , in some embodiments, the second balancing module may further include: a temperature sensor and a heat dissipation device.

[0326] In this embodiment, the temperature sensor is used to collect the actual temperature of the second balancing module.

[0327] The temperature sensor may be disposed near the fourth resistor.

[0328] The heat sink is connected to the positive electrode of the PACK corresponding to the second balancing module, and the switching state of the heat sink is controlled based on the actual temperature.

[0329] In some embodiments, the heat dissipation device may include a DC / DC converter and a fan.

[0330] The DC / DC converter is connected to the PACK.

[0331] During actual execution, when the BMU detects that the actual temperature of the second balancing module is greater than the fifth preset value, it controls to turn on the fan set in the second balancing module to dissipate heat for the second balancing module to reduce the temperature of the second balancing module.

[0332] In some embodiments, as shown in FIG11 , an embodiment of the present application further provides an electronic device 1100, comprising a processor 1101, a memory 1102, and a computer program stored in the memory 1102 and executable on the processor 1101. When the program is executed by the processor 1101, each process of the above-mentioned embodiment of the method for balancing control of a battery cluster is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0333] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0334] The present application also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the various processes of the above-mentioned embodiment of the battery cluster balancing control method are implemented, and the same technical effects can be achieved. To avoid repetition, they are not described here.

[0335] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0336] An embodiment of the present application further provides a computer program product, including a computer program, which implements the above-mentioned battery cluster balancing control method when executed by a processor.

[0337] The processor is the processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0338] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is configured to execute programs or instructions to implement the various processes of the above-mentioned embodiment of the battery cluster balancing control method, and can achieve the same technical effects. To avoid repetition, these are not described here.

[0339] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0340] Energy storage battery systems have developed rapidly in recent years, moving toward higher capacity, higher power density, and higher power integration. Consequently, the number of cells within these systems has also increased. Typically, an energy storage system consists of multiple battery clusters connected in series and parallel, each of which in turn consists of varying numbers of single cells connected in series and parallel. Due to limitations in production control and varying degrees of internal resistance aging during use, the internal resistance of each battery cluster increases with age, leading to varying currents flowing through each cluster during charge and discharge. This ultimately results in increasing inconsistencies in the capacity of the battery clusters, and the usable capacity of the energy storage battery system decreases accordingly.

[0341] Currently, the common method to solve the above problem is to adjust the cluster current of each battery cluster based on the SOC or voltage difference in the entire interval to balance the SOC between the battery clusters. However, for energy storage battery systems that use a cell system with both a "plateau area" (generally refers to an interval with a relatively slow voltage change rate) and a "non-plateau area" (generally refers to an interval with a relatively large voltage change rate), when the cell is in the "plateau area", the voltage changes relatively slowly. If the voltage difference is used as the adjustment criterion, it is easy to cause misadjustment due to sampling error; when the cell is in the "non-plateau area", the voltage changes rapidly. If only the SOC difference is used as the adjustment criterion, it is also easy to cause misadjustment due to SOC sampling error.

[0342] Therefore, how to accurately adjust the inconsistency between battery clusters according to the characteristics of the battery cells in the energy storage system is the technical problem that this application aims to solve.

[0343] This application describes a method for regulating an energy storage system for performing balanced control on the energy storage system. The energy storage system includes at least two battery clusters, each of which includes at least one battery cell. The method includes the following steps:

[0344] Determine whether the energy storage system is in the voltage plateau area or the voltage non-plateau area;

[0345] If the energy storage system is in the voltage plateau area, the maximum real-time SOC or minimum real-time SOC of all battery clusters is used as the basis for determining whether balancing is required, and the battery cluster is used as the balancing object;

[0346] If the energy storage system is in a voltage non-platform area, the maximum cell voltage or minimum cell voltage of all battery clusters is used as the basis for determining whether balancing is required, and all battery clusters are used as balancing objects.

[0347] In the present application, by detecting the working state of the energy storage system, it is determined whether the energy storage system is in the voltage platform area or the voltage non-platform area, and then selected as the basis for judging whether balancing is required. Specifically, when the energy storage system is working in the "voltage platform area", the voltage changes relatively slowly, and the maximum real-time SOC or minimum real-time SOC of all battery clusters is used as the basis for judging whether balancing is required, and the battery cluster is used as the balancing object; when the energy storage system is working in the "voltage non-platform area", the voltage changes rapidly, and the maximum cell voltage or minimum cell voltage of all battery clusters is used as the basis for judging whether balancing is required, and the battery cluster is used as the balancing object. In this way, the energy storage battery adjustment method of the present application can select the basis for targeted adjustment judgment according to the different working states of the energy storage system, and can more accurately grasp the timing of balancing adjustment of each battery cluster, thereby reducing the inconsistency between the battery clusters in real time and accurately, avoiding misadjustment caused by sampling error, SOC error, etc., improving the accuracy of balancing adjustment, and maximizing the charge and discharge capacity of the entire energy storage system.

[0348] To determine whether the energy storage system is in the voltage plateau region or the voltage non-plateau region, the OCV-SOC curve of the energy storage system is obtained by detecting the aging status of the energy storage system's battery cells. Generally speaking, the OCV-SOC curve of each energy storage system is set at the factory, so this curve can be directly used in the energy storage battery adjustment method of this application to identify the plateau and non-plateau regions.

[0349] However, as the energy storage system ages, the OCV-SOC curve changes from the factory setting. Therefore, the OCV-SOC curve can be updated based on the aging of the cells in the energy storage system's battery cluster by regularly monitoring the aging of the cells. The slope of the OCV-SOC curve can then be used to distinguish between voltage plateaus and non-voltage plateaus. The specific interval for reconstructing the OCV-SOC curve can be adjusted based on user needs.

[0350] The OCV-SOC curve obtained in this embodiment is shown in Figure 12. In the initial stage of charging or discharging, the voltage of the energy storage system changes rapidly, and the greater the charge and discharge rate, the faster the voltage changes. When the energy storage system enters a slowly changing stage, the smaller the charge and discharge rate, the longer the voltage plateau lasts. In the latter part of the charging or discharging of the energy storage system, the voltage of the energy storage system also changes faster, especially during discharge, when the external load voltage begins to drop sharply until it reaches the discharge cut-off voltage.

[0351] The OCV-SOC curve of the energy storage system under the implementation mode of the present application is a curve drawn with the internal voltage OCV of the energy storage system as the vertical coordinate and the state of charge SOC of the energy storage system as the horizontal coordinate. The aging state of the battery cells of the energy storage system is detected, and the OCV-SOC curve of the energy storage system is constructed. The voltage platform area and the voltage non-platform area are divided according to the slope of the OCV-SOC curve. The voltage platform area changes slowly, so the slope is small and can be maintained unchanged within a certain area for a long time. Therefore, the confirmation process of the voltage platform area is shown in Figure 13. It is calculated whether the slope of the OCV-SOC curve is less than the set threshold. If it is less than the threshold, it can be judged to be in the voltage platform area, otherwise it is in the voltage non-platform area.

[0352] Based on the characteristics of the energy storage system, combined with the OCV-SOC curve of the energy storage system shown in Figure 12, it is not difficult to find that generally speaking, the energy storage system is in the voltage non-plateau region during the initial stages of charge and discharge. As the charge and discharge process stabilizes, it gradually enters the voltage plateau region. As the charge and discharge process enters the later stages, the voltage undergoes drastic changes and enters the voltage non-plateau region again. The endpoints of the voltage plateau region are SOCtag1 and SOCtag2, respectively, with 0 < SOCtag1 < SOCtag2 < 1. SOCtag1 is the starting point of the voltage plateau region, and SOCtag2 is the end point of the voltage plateau region. In other words, SOCtag1 is the starting SOC value of the voltage plateau region, and SOCtag2 is the ending SOC value of the voltage plateau region.

[0353] The process flow of the energy storage system regulation method under this embodiment is shown in Figure 14. The PID control algorithm can be used to adjust the target current value of the battery cluster in real time in combination with the charge and discharge status of the energy storage system, resulting in more targeted and accurate regulation. In other words, the charge and discharge status of the energy storage system is obtained, and inter-cluster balancing adjustments are performed on the energy storage system based on the charge and discharge status of the energy storage system. The following will determine the specific measures for balancing the battery clusters in the energy storage system based on whether the energy storage system is in the charging or discharging process and whether the energy storage system is operating in the voltage plateau region or the voltage non-plateau region. These balancing adjustment schemes can be divided into four conditions: "charging and in the voltage plateau region," "charging and in the voltage non-plateau region," "discharging and in the voltage plateau region," and "discharging and in the voltage non-plateau region."

[0354] The following embodiments are described using a working range of an energy storage system as an example. The energy storage system adjustment method of the present application can be applied to an energy storage system working range that includes both a voltage platform area and a voltage non-platform area, and can also be applied to a voltage platform area or a voltage non-platform area separately. The division of the energy storage system working range is not limited to this embodiment and can be multiple.

[0355] Example 1:

[0356] When the energy storage system is in the charging process, the battery cluster will quickly enter the plateau area and stay in the voltage non-plateau area from 0 to SOCtag1 for a very short time. As the charging process continues, the internal voltage of the battery cluster continues to increase until the maximum real-time SOC of the battery cluster is greater than SOCtag2 and enters the voltage non-plateau area. Therefore, in this embodiment, during the charging process, the comparison between SOCmax and SOCtag2 is used as the basis for judging the voltage plateau area and the voltage non-plateau area.

[0357] In this embodiment, as shown in FIG15 , the energy storage system is in the charging process, and the maximum real-time SOC of all battery clusters, i.e., SOCmax, enters between SOCtag1 and SOCtag2, SOCtag1≤SOCmax≤SOCtag2. In other words, each battery cluster of the energy storage system is in the voltage platform area. The regulated current of each battery cluster is calculated by the following formula: I i =min{x i *I 总 ,I i最大允许充电电流}

[0358] Among them, I i Indicates the target current value of each battery cluster, x i Represents the cluster current distribution weight coefficient of each battery cluster, I 总 Represents the total current input to the energy storage system. By calculating the target current value I of each battery clusteri Not greater than the maximum allowable charging current of the battery cluster, which is the smaller value between the calculated value and the maximum allowable charging current;

[0359] Cluster current distribution weight coefficient x i The calculation formula is as follows:

[0360] Among them, MaxSoc i Indicates the maximum real-time SOC of each cluster, Cap i Indicates the nominal capacity of each battery cluster at the current temperature.

[0361] Example 2:

[0362] The energy storage system adjustment method of this embodiment is optimized and improved on the first embodiment. The optimization is to calculate the target current value I of each battery cluster. i The total current I input to the energy storage system used in 总 It is the sum of the adjusted target current values ​​of each battery cluster at the previous moment.

[0363] By using the sum of the adjusted target current values ​​of each battery cluster at the previous moment as the total current input to the energy storage system at the current moment, the results can be reused and calculated, which can improve the calculation accuracy of the target current value and facilitate the precise energy distribution of the external input current. In addition, when the total current input to the energy storage system is large, the target current values ​​calculated based on the cluster current distribution weight coefficients of each battery cluster exceed the maximum allowable charging current of each battery cluster. Even if the current of each battery cluster is reduced, it will still be the maximum allowable charging current. This will make it impossible to reduce the consistency difference between clusters by adjusting the current size of each battery cluster. Therefore, using the sum of the adjusted target current values ​​of each battery cluster at the previous moment as the total current input to the energy storage system at the current moment can better achieve the purpose of balanced regulation of the energy storage system.

[0364] That is, the target current value I of each battery cluster is calculated. i The calculation formula is as follows:

[0365] in, is the total current input to the energy storage system at the current moment;

[0366] The calculation formula for the total current input to the energy storage system at the current moment is as follows:

[0367] in, It is the adjusted target current value of each battery cluster at the previous moment.

[0368] Example 3:

[0369] In this embodiment, as shown in FIG16 , when the energy storage system is in the charging process and the maximum real-time SOC of all battery clusters, i.e., SOCmax, is greater than SOCtag2, SOCtag2 < SOCmax < 1, that is, each battery cluster of the energy storage system is in a voltage non-platform region, the maximum cell voltage in each battery cluster is compared with the average value of the maximum cell voltages in all battery clusters. When the difference between the maximum cell voltage in a battery cluster and the average value of the maximum cell voltages in all battery clusters exceeds a preset voltage difference threshold, current regulation is performed on the battery cluster; otherwise, current regulation is not performed on the battery cluster.

[0370] When the difference between the maximum cell voltage in the battery cluster and the average value of the maximum cell voltages in all battery clusters exceeds a preset voltage difference threshold, the current regulation of the battery cluster is calculated using the following formula:

[0371] Among them, MaxVolt i Indicates the maximum cell voltage of each battery cluster, i indicates the number of battery clusters, MaxVolt avg Indicates the average voltage of the maximum cell voltage of all battery clusters, Indicates the current amount that needs to be adjusted in the current cycle, K p Represents the proportional adjustment coefficient, K i Indicates the integral adjustment coefficient, K d represents the differential adjustment coefficient, Indicates the target current value of the previous cycle, Indicates the target current value of the current cycle.

[0372] When comparing the difference between the maximum cell voltage in the battery cluster and the average value of the maximum cell voltages in all battery clusters with a preset voltage difference threshold, the degree of discreteness between the two values ​​is calculated through discrete calculation, thereby determining whether the battery cluster requires current regulation.

[0373] The amount of current that needs to be adjusted during the current cycle When calculating , remove the integral adjustment item when one of the following conditions occurs

[0374] The maximum cell voltage of the battery cluster being adjusted is lower than the sum of the average voltage of the maximum voltages of all battery clusters and a preset voltage difference threshold;

[0375] Current working state switching (the current working state of a battery cluster generally includes a static state, a charging state, and a discharging state. The current working state switching here refers to the current working state of the battery cluster changing from a charging state to a discharging state, or the current working state of the battery cluster changing from a charging state to a static state);

[0376] conduct The calculation integration time exceeds the preset adjustment step;

[0377] The actual current value of the current cycle and the target current value of the previous cycle The difference between the actual current value of the current cycle and the target current value of the previous cycle collected by the current collection unit exceeds the preset range. There is an obvious difference, indicating that the current regulation has failed, so the integral regulation term is removed and recalculated.

[0378] An experimental example will be used to illustrate Examples 2 and 3. In this example, the energy storage system is equipped with two battery clusters, each with equal nominal capacity (Cap). Balance adjustment is performed on the energy storage system in this example based on two operating states: "charging and in the voltage plateau region" and "charging and in the voltage non-plateau region."

[0379] The target current values ​​for the energy storage system when the operating state is "charging and in the voltage plateau area" are as follows:

[0380] Detect the maximum real-time SOC of each battery cluster in the energy storage system in the charging state and compare the maximum real-time SOC with the end point SOCtag2 of the voltage plateau region. At time t-1 and time t, the maximum real-time SOC of the two battery clusters are both less than the end point SOCtag2 of the voltage plateau region, indicating that the two battery clusters are in the voltage plateau region at both times.

[0381] At time t-1, the current distribution weight coefficient is calculated based on the maximum real-time SOC of each battery cluster and the endpoint SOCtag2 of the voltage plateau area. The distribution current is then calculated based on the current distribution weight coefficient and the total current externally input to the energy storage system. The calculated distribution current is then compared with the maximum allowable charging current of the battery cluster, and the smaller value is taken as the target current value. Since the calculated distribution current of the two battery clusters is greater than the maximum allowable charging current, the maximum allowable charging current is selected as the target current value at time t-1 for both battery clusters. The current externally input to each battery cluster is controlled according to the target current value.

[0382] At time t, the current distribution weight coefficient is calculated based on the maximum real-time SOC of each battery cluster and the end point SOCtag2 of the voltage platform area. The distribution current is then calculated based on the sum of the current distribution weight coefficient and the adjusted target current value of each battery cluster at the previous moment. The calculated distribution current is then compared with the maximum allowable charging current of the battery cluster, and the smaller value is taken as the target current value. Since the distribution current calculated by the first battery cluster is greater than the maximum allowable charging current, the first battery cluster selects the maximum allowable charging current as the target current value of the first battery cluster at time t, and the current externally input to the first battery cluster is controlled according to the target current value. Since the distribution current calculated by the second battery cluster is less than the maximum allowable charging current, the second battery cluster selects the calculated distribution current as the target current value of the second battery cluster at time t, and the current externally input to the second battery cluster is controlled according to the target current value.

[0383] The target current values ​​for the energy storage system when the operating state is "charging and in the voltage non-plateau area" are as follows:

[0384] Detect the maximum real-time SOC of each battery cluster in the energy storage system in the charging state and compare it with the end point SOCtag2 of the voltage plateau region. At time t-1 and time t, the maximum real-time SOC of both battery clusters is greater than the end point SOCtag2 of the voltage plateau region, indicating that both battery clusters are in the voltage non-plateau region at both times.

[0385] At time t-1, the maximum cell voltage in the two battery clusters is subtracted from the average of the maximum cell voltages in the two battery clusters and then compared with the voltage difference threshold. If the difference exceeds the preset voltage difference threshold, current regulation is performed on the battery cluster. The average value of the maximum cell voltage in the two battery clusters is 3480mV. The maximum cell voltage of the first battery cluster is lower than this average value, while the maximum cell voltage of the second battery cluster is 70mV lower than this average value. This difference is greater than the voltage difference threshold (50mV). Therefore, at time t-1, current regulation is performed only on the second battery cluster, and current regulation does not need to be performed on the first battery cluster. As for the regulated current of the second battery cluster, the maximum cell voltage of the two battery clusters is substituted into the formula to calculate the regulated current, and ultimately determine the target current of the second battery cluster.

[0386] At time t, the average of the maximum cell voltages in the two battery clusters minus the maximum cell voltages in the two battery clusters is subtracted from the maximum cell voltage in the two battery clusters and compared to the voltage difference threshold. If the difference exceeds the preset voltage difference threshold, current regulation is performed on that battery cluster. The average maximum cell voltage in the two battery clusters is 3505mV. The maximum cell voltage of the first battery cluster is lower than this average, while the difference between the maximum cell voltage of the second battery cluster and this average is 55mV, which is greater than the voltage difference threshold (50mV). Therefore, at time t, current regulation is performed only on the second battery cluster, eliminating the need for current regulation on the first battery cluster. The current regulation for the second battery cluster is calculated by substituting the maximum cell voltages of the two battery clusters into the formula to determine the target current for the second battery cluster.

[0387] Example 4:

[0388] When the energy storage system is in the discharge process, the battery cluster will quickly enter the plateau area and stay in the voltage non-plateau area of ​​SOCtag2-1 for a very short time. As the discharge process continues, the internal voltage of the battery cluster continues to decrease until the minimum real-time SOC of the battery cluster is less than SOCtag1 and enters the voltage non-plateau area. Therefore, in this embodiment, during the discharge process, the comparison between SOCmin and SOCtag1 is used as the basis for judging the voltage plateau area and the voltage non-plateau area.

[0389] In this embodiment, as shown in FIG17 , the energy storage system is in the discharge process, and the minimum real-time SOC of all battery clusters, i.e., SOCmin, falls between SOCtag1 and SOCtag2, where SOCtag1 ≤ SOCmin ≤ SOCtag2. In other words, each battery cluster of the energy storage system is in the voltage plateau region. The regulated current of each battery cluster is calculated using the following formula:

[0390] Among them, I i Indicates the target current value of each battery cluster, x i Represents the cluster current distribution weight coefficient of each battery cluster, I 总 Indicates the total current output by the energy storage system to the external load;

[0391] Cluster current distribution weight coefficient x i The calculation formula is as follows:

[0392] Among them, MinSoc i Indicates the minimum real-time SOC of each cluster, Cap i Indicates the nominal capacity of each battery cluster at the current temperature.

[0393] Example 5:

[0394] The energy storage system adjustment method of this embodiment is optimized and improved on the fourth embodiment. The optimization is to calculate the target current value I of each battery cluster. i The total current I output by the energy storage system to the external load 总 It is the sum of the adjusted target current values ​​of each battery cluster at the previous moment. The sum of the adjusted target current values ​​of each battery cluster at the previous moment is used as the total current output by the energy storage system to the external load at the current moment, and the result is reused for calculation. This can improve the calculation accuracy of the target current value, and is conducive to the precise distribution of energy of the output current. In addition, when the total current output by the energy storage system to the external load is large, the target current value calculated according to the cluster current distribution weight coefficient of each battery cluster exceeds the maximum allowable discharge current of each battery cluster. Even if the current of each battery cluster is reduced, it is still the maximum allowable discharge current. This will make it impossible to reduce the consistency difference between clusters by adjusting the current size of each battery cluster. Therefore, the sum of the adjusted target current values ​​of each battery cluster at the previous moment is selected as the total current output by the energy storage system to the external load at the current moment, which can better achieve the purpose of balanced regulation of the energy storage system.

[0395] That is, the target current value I of each battery cluster is calculated. i The calculation formula is as follows:

[0396] in, The total current output from the energy storage system to the external load at the current moment;

[0397] The calculation formula for the total current input to the energy storage system at the current moment is as follows:

[0398] in, It is the adjusted target current value of each battery cluster at the previous moment.

[0399] Example 6:

[0400] In this embodiment, as shown in FIG18 , when the energy storage system is in the discharge process and the minimum real-time SOC of all battery clusters, i.e., SOCmin, is less than SOCtag1, 0<SOCmin<SOCtag1, that is, each battery cluster of the energy storage system is in a voltage non-platform region, the minimum cell voltage in each battery cluster is compared with the average value of the minimum cell voltages in all battery clusters. When the difference between the minimum cell voltage in a battery cluster and the average value of the minimum cell voltages in all battery clusters exceeds a preset voltage difference threshold, current regulation is performed on the battery cluster; otherwise, current regulation is not performed on the battery cluster.

[0401] When the difference between the minimum cell voltage in the battery cluster and the average value of the minimum cell voltages in all battery clusters exceeds a preset voltage difference threshold, the current regulation of the battery cluster is calculated using the following formula:

[0402] Among them, MinVolt i Indicates the minimum cell voltage of each battery cluster, i indicates the number of battery clusters, MinVolt avg Indicates the average voltage of the minimum cell voltage of all battery clusters, Indicates the current amount that needs to be adjusted in the current cycle, K p Represents the proportional adjustment coefficient, K i Indicates the integral adjustment coefficient, K d represents the differential adjustment coefficient, Indicates the target current value of the previous cycle, Indicates the target current value of the current cycle.

[0403] The amount of current that needs to be adjusted during the current cycle When calculating the integral adjustment term, if one of the following conditions occurs, remove the integral adjustment term.

[0404] The minimum cell voltage of the battery cluster to be adjusted is higher than the difference between the average voltage of the minimum voltages of all battery clusters and a preset voltage difference threshold;

[0405] Current working state switching (the current working state of a battery cluster generally includes a static state, a charging state, and a discharging state. The current working state switching here refers to the current working state of the battery cluster changing from a discharging state to a charging state, or from a discharging state to a static state);

[0406] conduct The calculation integration time exceeds the preset adjustment step;

[0407] The actual current value of the current cycle and the target current value of the previous cycle The difference between the actual current value of the current cycle and the target current value of the previous cycle collected by the current collection unit exceeds the preset range. There is an obvious difference, indicating that the current regulation has failed, so the integral regulation term is removed and recalculated.

[0408] An experimental example will be used to illustrate Examples 2 and 3. In this example, the energy storage system is equipped with two battery clusters, each with equal nominal capacity (Cap). Balance adjustment is performed on the energy storage system in this example based on two operating states: "discharging in the voltage plateau region" and "discharging in the voltage non-plateau region."

[0409] The target current values ​​for the energy storage system when the operating state is "discharging and in the voltage plateau area" are as follows:

[0410] Detect the minimum real-time SOC of each battery cluster in the energy storage system in the discharge state and compare it with the starting point SOCtag1 of the voltage plateau region. At time t-1 and time t, the minimum real-time SOC of the two battery clusters are both greater than the starting point SOCtag1 of the voltage plateau region, indicating that the two battery clusters are in the voltage plateau region at both times.

[0411] At time t-1, the current distribution weight coefficient is calculated based on the minimum real-time SOC of each battery cluster and the starting point SOCtag1 of the voltage plateau area. The distribution current is then calculated based on the current distribution weight coefficient and the total current externally input to the energy storage system. The calculated distribution current is then compared with the maximum allowable discharge current of the battery cluster, and the smaller value is taken as the target current value. Since the calculated distribution current of the two battery clusters is greater than the maximum allowable discharge current, the maximum allowable discharge current is selected as the target current value at time t-1 for both battery clusters. The current externally input to each battery cluster is controlled according to the target current value.

[0412] At time t, the current distribution weight coefficient is calculated based on the minimum real-time SOC of each battery cluster and the starting point SOCtag1 of the voltage platform area, and the distribution current is then calculated based on the sum of the current distribution weight coefficient and the adjusted target current value of each battery cluster at the previous moment. The calculated distribution current is then compared with the maximum allowable discharge current of the battery cluster, and the smaller value is taken as the target current value. Since the distribution current calculated by the second battery cluster is greater than the maximum allowable discharge current, the second battery cluster selects the maximum allowable discharge current as the target current value of the second battery cluster at time t, and the current externally input to the second battery cluster is controlled based on this target current value. Since the distribution current calculated by the first battery cluster is less than the maximum allowable discharge current, the first battery cluster selects the calculated distribution current as the target current value of the first battery cluster at time t, and the current externally input to the first battery cluster is controlled based on this target current value.

[0413] The target current values ​​for the energy storage system when the operating state is "discharging and in the voltage non-plateau region" are as follows:

[0414] Detect the minimum real-time SOC of each battery cluster in the energy storage system in the discharge state and compare it with the starting point SOCtag1 of the voltage plateau region. At time t-1 and time t, the minimum real-time SOC of the two battery clusters are both less than the starting point SOCtag1 of the voltage plateau region, indicating that the two battery clusters are in the voltage non-plateau region at both times.

[0415] At time t-1, the average value of the minimum cell voltages in the two battery clusters is subtracted from the minimum cell voltages in the two battery clusters and then compared with the voltage difference threshold. If the difference exceeds the preset voltage difference threshold, current regulation is performed on the battery cluster. The average value of the minimum cell voltages in the two battery clusters is 3075mV. This average value is smaller than the minimum cell voltage of the second battery cluster, so current regulation is not required for the second battery cluster. However, the average value of the minimum cell voltages in the two battery clusters is larger than the minimum cell voltage of the first battery cluster, and the difference is 65mV. This difference is greater than the voltage difference threshold (50mV), so at time t-1, only current regulation is performed on the first battery cluster, and current regulation is not required for the second battery cluster. As for the regulated current of the first battery cluster, the minimum cell voltages of the two battery clusters are substituted into the formula to calculate the regulated current, and ultimately determine the target current of the second battery cluster.

[0416] At time t, the average of the minimum cell voltages in the two battery clusters minus the minimum cell voltages in the two battery clusters is subtracted from the average of the minimum cell voltages in the two battery clusters and compared to the voltage difference threshold. If the difference exceeds the preset voltage difference threshold, current regulation is performed on that battery cluster. The average of the minimum cell voltages in the two battery clusters is 3069.5mV, which is lower than the minimum cell voltage of the second battery cluster. Therefore, current regulation is not required for the second battery cluster. However, the average of the minimum cell voltages in the two battery clusters is higher than the minimum cell voltage of the first battery cluster by 59.5mV. This difference is greater than the voltage difference threshold (50mV). Therefore, at time t, current regulation is still performed only on the first battery cluster, and current regulation is not required on the second battery cluster. As for the regulated current of the first battery cluster, the minimum cell voltages of the two battery clusters are substituted into the formula to calculate the regulated current, ultimately determining the target current of the second battery cluster.

[0417] Example 7:

[0418] This embodiment provides a computer medium executed by a data processing device. The data processing device has a processor containing program code. When executing the program code, the processor executes the energy storage battery balancing control method as described in any one of Embodiments 1 to 6.

[0419] Example 8:

[0420] This embodiment provides an energy storage system, which includes a battery management unit and at least two battery clusters. The battery management unit is configured to execute the energy storage system adjustment method as described in any one of Embodiments 1 to 6 to balance the battery clusters in the energy storage system.

[0421] Example 9:

[0422] This embodiment provides a power generation system, which includes an energy storage system and a central control unit. The central control unit is configured to execute the energy storage system adjustment method as described in any one of Embodiments 1 to 6 to perform balancing adjustment on the battery clusters in the energy storage system.

[0423] Energy storage batteries are batteries that convert chemical energy into electrical energy. They store electrical energy while charging and then release it when needed to meet power demands. Key applications include power system energy storage, transportation energy storage, distributed energy storage, and electronic equipment energy storage.

[0424] Energy storage batteries typically consist of several battery packs, which can be connected in series or parallel to form a battery string. In parallel connection mode, if there are too many parallel packs in an energy storage battery, the internal resistance of the battery pack will change after extended use. Due to the varying performance parameters of the batteries in the pack, the internal resistance of each cell will vary significantly after extended use, leading to differences in electromotive force (EMF). This can lead to even greater differences in the EMF between battery packs. The greater the number of parallel packs, the greater the chance of this difference. At this point, the battery pack with higher EMF will discharge to the battery pack with lower EMF, creating a circulating current between the connected battery packs. This high circulating current can cause the batteries to heat up, accelerating the aging of the battery with higher EMF and shortening its lifespan.

[0425] There are many solutions to the problem of battery pack series circulation. However, due to the different capacities of old and new battery packs or battery packs of different models, the battery packs that make up the battery pack are prone to obvious aging differences during later use, and the consistency differences become larger, which will still affect the life of the battery pack. As the battery pack ages, its internal resistance will change due to factors such as electrolyte water loss, plate and connecting belt corrosion, plate sulfation, plate deformation and active material shedding. Different battery packs may have different aging phenomena, resulting in different changes in their internal resistance. The change in internal resistance will cause the temperature of the battery pack to change during discharge. The available capacity of the battery pack will change with the increase in temperature. Through testing, it is found that when the internal resistance of the battery pack is greater than 2 times the initial value (base value), the capacity of the battery pack will be less than 80% of its rated capacity. In addition, the increase in the internal temperature of the battery pack will further damage the battery, and the battery cycle life and maximum available capacity will gradually decrease. According to experiments, under a normal temperature of 25°C, if the temperature rises by 6-10°C, the high temperature will increase the floating charge current of the battery and cause the battery life to be reduced by half. In other words, the different internal temperatures of each battery pack will further increase the aging differences of each battery pack.

[0426] Since the internal resistance of the battery pack changes, the internal temperature of each battery pack that makes up the energy storage battery will also vary with the operating time. Correspondingly, the temperature change of the battery pack during discharge can effectively reflect the health and operating conditions of the battery pack, showing the consistency differences between the individual battery packs. Based on this, the applicant considered controlling the battery current sharing based on the battery pack temperature, further improving the battery pack current sharing control, and controlling the internal temperature of the battery pack to maintain a relatively uniform and balanced state.

[0427] Therefore, how to achieve current sharing control and internal temperature control according to the status of each battery pack in the battery pack is the technical problem that this application aims to solve.

[0428] The embodiment of the present application also provides a method for controlling current sharing of energy storage batteries.

[0429] In this embodiment, an energy storage battery consisting of four battery packs is taken as an example, wherein the capacity C1 of battery pack 1 is 200AH, the capacity C2 of battery pack 2 is 200AH, the capacity C3 of battery pack 3 is 220AH, and the capacity C4 of battery pack 4 is 240AH.

[0430] The number of battery packs in the energy storage battery can be a natural number greater than or equal to 2. The principle of the current sharing control calculation is the same as that of the case of four battery packs in this embodiment. Please note that the following examples will not be given here.

[0431] The standard definition of the battery health status parameter SOH is the ratio of the capacity released by the power battery from a fully charged state at a certain rate to the cut-off voltage under standard conditions to its corresponding nominal capacity (actual initial capacity). This ratio is a reflection of the battery health status. In simple terms, it is the ratio of the actual value to the nominal value of certain directly measurable or indirectly calculated performance parameters after the battery has been used for a period of time. It is used to judge the state of the battery after its health status has declined and to measure the health of the battery. It is actually reflected in the changes in certain parameters inside the battery (such as internal resistance, capacity, etc.). The battery health status parameter SOH in this embodiment is defined and calculated from the perspective of the remaining battery power: SOH = Qaged / Qnew

[0432] Among them, Qaged is the maximum power currently available in the battery pack, and Qnew is the maximum power of the battery pack when it is not in use.

[0433] During the operation of the energy storage battery, the voltage and current of each battery pack are monitored to detect and calculate the maximum available power Qaged of the battery pack. The maximum power Qnew of the battery pack when not in use is a factory parameter and is known. Therefore, the battery health status parameter SOH can be relatively easily obtained from existing technologies.

[0434] In this embodiment, the battery health state parameter SOH1 of battery pack 1 is 90%, the battery health state parameter SOH2 of battery pack 2 is 85%, the battery health state parameter SOH3 of battery pack 3 is 80%, and the battery health state parameter SOH4 of battery pack 4 is 80%.

[0435] The battery state of charge (SOC) parameter refers to the state of charge (SOC) of the battery pack. It primarily reflects the remaining capacity of the battery pack and is a real-time, changing value numerically defined as the ratio of the remaining capacity to the battery pack capacity. It is typically expressed as a percentage, ranging from 0 to 1. When SOC = 0, the battery pack is fully discharged. When SOC = 1, the battery is fully charged. The battery state of charge parameter (SOC) is typically measured via the battery terminal voltage. Currently, monitoring of the battery state of charge parameter (SOC) is typically included in energy storage battery status monitoring.

[0436] Example 1:

[0437] This embodiment describes a method for controlling current sharing of energy storage batteries. The method is used to control current sharing of multiple battery packs. The battery packs are connected in parallel to form a battery pack. The selected battery packs have the same output voltage to avoid circulating current problems during initial output. The method includes the following steps:

[0438] Step S1: After the energy storage battery system starts discharging, the capacity Ci, battery health status parameter SOHi, and battery state of charge parameter SOCi of each battery pack i are read. In this embodiment, i is a natural number from 1 to 4, but is not limited thereto and can be expanded to more than 10.

[0439] Step S3: determining the discharge current Current (sys) required by the electrical load connected to the battery pack;

[0440] Step S5: Calculate the desired output current Current(i) of each battery pack based on the capacity Ci of battery pack i, the battery health status parameter SOHi, the battery charge status parameter SOCi, and the discharge current Current(sys) required by the load connected to the battery pack. The specific calculation formula is as follows:

[0441] Step S7: controlling the output current of each battery pack according to the calculated simulated output current Current(i) of each battery pack.

[0442] In this embodiment, when current balancing control is performed, the battery state of charge parameter SOC1 of battery pack 1 is 70%, the battery state of charge parameter SOC2 of battery pack 2 is 68%, the battery state of charge parameter SOC3 of battery pack 3 is 69%, and the battery state of charge parameter SOC4 of battery pack 4 is 70%. The discharge current Current(sys) required by the load is 100A.

[0443] According to the calculation formula of the simulated output current Current(i), the simulated output current of each battery pack is calculated as follows:

[0444] The output current of each battery pack is controlled according to the calculated simulated output current Current(i) of the battery pack, that is, the simulated output current Current(1) corresponding to battery pack 1 is 25.33A, the simulated output current Current(2) corresponding to battery pack 2 is 23.24A, the simulated output current Current(3) corresponding to battery pack 3 is 24.41A, and the simulated output current Current(4) corresponding to battery pack 4 is 27.02A.

[0445] Control of each battery pack's intended output current, Current(i), is achieved by adjusting the resistance within the battery pack. Programmable logic resistors are connected in series with the output circuits of each battery pack. These resistors receive control commands from the energy storage converter, battery controller, and other components to adjust the branch circuit connected in series with the corresponding battery pack to the intended output current.

[0446] Alternatively, the desired output current Current(i) of each battery pack can be controlled by adjusting the output voltage of the battery pack. For example, this can be achieved by performing voltage conversion within each battery pack. A DC conversion module is connected in series within each battery pack. The output voltage of the battery pack is adjusted by the DC conversion module to adjust the branch voltage, thereby changing the output current of the corresponding branch.

[0447] The above calculation of the intended output current Current(i) of the battery pack can be completed in a control device such as an energy storage inverter and a battery controller; or the calculation of the intended output current Current(i) of the battery pack can be completed in an external computer or other computing device, and then the specific branch current control is completed by a controller such as an energy storage inverter and a battery controller that can send control instructions to the battery pack, thereby realizing the control of the output current on the branch of each battery pack.

[0448] Example 2:

[0449] The energy storage battery current sharing control method of this embodiment is improved on the basis of Example 1. The improvement is that in step S1, the internal temperature Ti of each battery pack is collected and a temperature threshold coefficient Tavg is configured. After the calculation of the intended output current Current(i) of each battery pack is completed, a secondary adjustment is made based on the internal temperature Ti of the battery pack and the temperature threshold coefficient Tavg to form the output control current Current'(i).

[0450] That is, the energy storage battery current sharing control method of this embodiment calculates and controls the output current of each battery pack based on the SOC, SOH, and capacity of each battery pack that makes up the energy storage battery, thereby achieving current sharing control for each battery pack. In addition, the temperature in each battery pack can be monitored. The temperature rise change of the battery pack temperature can effectively reflect the operating stability of the battery pack (battery health status). Combined with the temperature monitoring results, the output current of each battery pack is recalculated and adjusted to achieve further current sharing control. In this way, the circulating current problem caused by parallel connection of battery packs can be eliminated. By monitoring the battery pack temperature and adopting the current sharing control method, the aging convergence control of each battery pack can be achieved, the consistency difference between each battery pack can be reduced, and the overall life of the energy storage battery can be extended.

[0451] In one embodiment, the internal temperature Ti of each battery pack is collected in step S1 and configured with a temperature threshold coefficient Tavg. After calculating the desired output current Current(i) for each battery pack, a secondary adjustment is made based on the battery pack's internal temperature Ti and the temperature threshold coefficient Tavg to form the output control current Current'(i). Based on the changes in the internal temperature Ti of each battery pack, the output current of a battery pack is calculated and adjusted when the temperature change of a battery pack is no less than a temperature difference threshold t. The temperature difference threshold t is between 2 and 10°C.

[0452] In a further embodiment, step S2 is further included, wherein the maximum value Tmax and minimum value Tmin of the internal temperature Ti of the battery pack collected during the monitoring process are read, and the difference between the maximum value Tmax and the minimum value Tmin is calculated as the temperature change value of the battery pack. In this embodiment, the temperature difference threshold t is set to 4°C. When the internal temperature change value of the battery pack exceeds 4°C, a control mechanism based on the internal temperature of the battery pack is introduced.

[0453] Then in step 6, the output control current Current'(i) is formed by secondary adjustment based on the internal temperature Ti of the battery pack and the temperature threshold coefficient Tavg. The calculation formula of the output control current Current'(i) is as follows:

[0454] Among them, the temperature threshold coefficient Tavg is the average temperature of each battery pack, that is,

[0455] In this embodiment, after a period of operation, the temperature detection statistics of each battery pack are as follows:

[0456] It can be found that the temperature change value inside the second battery pack is greater than 4° C., and the output control current of the second battery pack needs to be calculated.

[0457] At this time, the temperature threshold coefficient Tavg is equal to 32.75°C. According to the calculation in Example 1, Current(2) is 23.24A. This is used to calculate the output control current Current'(2) of the second battery pack.

[0458] In summary, the output control current corresponding to the adjusted second battery pack is 23.06A.

[0459] After the value of the battery pack's output control current Current'(i) is determined, the output current Current'(i) of the battery pack is controlled by adjusting the resistance within the battery pack. For example, a programmable logic resistor is connected in series with each battery pack's output circuit. Each programmable logic resistor receives control commands from the energy storage converter, battery controller, etc., adjusting the branch circuit connected in series with the corresponding battery pack to the desired output current value.

[0460] Alternatively, the output current Current'(i) of each battery pack can be controlled by adjusting the output voltage of the battery pack. For example, this can be achieved by performing voltage conversion within each battery pack. Each battery pack is connected in series with a DC conversion module. The output voltage of the battery pack is adjusted by the DC conversion module to adjust the branch voltage, thereby changing the output current of the corresponding branch.

[0461] The above calculation of the output current Current'(i) of the battery pack can be completed in a control device such as an energy storage inverter and a battery controller; or the calculation of the output current Current'(i) of the battery pack can be completed in an external computer or other computing device, and then the specific branch current is controlled by a controller such as an energy storage inverter and a battery controller that can send control instructions to the battery pack, thereby realizing the control of the output current on the branch of each battery pack.

[0462] Example 3:

[0463] The energy storage battery current sharing control method of this embodiment is improved on the basis of embodiment 1 or embodiment 2, as shown in FIG21 , and the improvement is:

[0464] In step S1, the real-time capacity Qi and the maximum allowable output power Pi of each battery pack i are also read;

[0465] In step S3, the power P(sys) required by the electrical load connected to the battery pack must also be determined;

[0466] The process also includes step S4, comparing the real-time capacities Qi of the battery packs i, discharging the battery packs with larger real-time capacities first while meeting the power requirements of the electrical load, and calculating and determining the intended output current Current(i) of each battery pack after the real-time capacities of the battery packs are balanced.

[0467] Due to the differences in the capacity of each battery pack, the available capacity of each battery pack will be different after charging is completed, or due to the different battery health status of each battery pack, the real-time capacity of each battery pack will also be different after a period of storage or discharge. The differences in battery packs are likely to cause circulation current. If the available capacity of each battery pack can be normalized, that is, the available capacity of each battery pack is made to converge, the occurrence of circulation current can be better avoided. On this basis, the discharge current of each battery pack can be further controlled based on the battery health status, which can better make the aging of the battery packs converge and further avoid the occurrence of circulation current.

[0468] For example, consider an energy storage battery consisting of four battery packs. Battery pack 1 has a capacity of 200AH (C1), 200AH (C2), 220AH (C3), and 240AH (C4). When fully charged, the actual capacity (i.e., usable capacity) of each battery pack is: 195AH (Q1) for battery pack 1, 198AH (Q2) for battery pack 2, 210AH (Q3) for battery pack 3, and 220AH (Q4) for battery pack 4. The maximum allowable output power of each battery pack is: 2kW (P1) for battery pack 1, 2.5kW (P2) for battery pack 2, 2.5kW (P3) for battery pack 3, and 3kW (P4) for battery pack 4.

[0469] Arrange the above battery packs in descending order according to their real-time capacities, and control the battery packs to output current in succession at a level not higher than the maximum allowable output power in the arranged order. That is, the discharge order is battery pack 4, battery pack 3, battery pack 2, and finally battery pack 1.

[0470] If the power P(sys) required by the load connected to the battery pack is 3 kW, battery pack 4 will directly provide power until the real-time capacity of battery pack 4 reaches the same level as the available capacity Q1 of battery pack 1. If power is to continue, battery pack 2 will switch to supply power. However, since battery pack 2's maximum allowable output power P2 is 2.5 kW, it is less than the 3 kW power required by the load and cannot meet the load's power demand. Therefore, battery pack 3 will also provide power, but at its maximum allowable output power P2. Battery pack 3 will provide the remaining power until the real-time capacity of battery pack 2 reaches the same level as the available capacity Q1 of battery pack 1. Then, battery pack 3 is used for power supply. However, the maximum allowable output power P3 of battery pack 3 is 2.5 kW, which cannot meet the power demand of the electrical load. Therefore, battery pack 3 is controlled to supply power at the maximum allowable output power P3, and the remaining power (0.5 kW) is evenly shared by battery pack 1, battery pack 2, and battery pack 4. This is done until the real-time capacity of the four battery packs is balanced and reaches 195 AH, thereby achieving capacity balance for each battery pack in the energy storage battery. Then, the method of Example 1 or Example 2 is used to further achieve current equalization output control of the energy storage battery.

[0471] If the power P(sys) required by the electrical load connected to the battery pack is 5 kW, then battery pack 4 and battery pack 3 will supply power simultaneously. At this time, battery pack 4 outputs at the maximum allowable output power of 3 kW, while battery pack 3 outputs at an output power of 2 kW. This will continue until the real-time capacity of battery pack 4 drops to 195AH (the real-time capacity of battery pack 1, which is also the minimum real-time capacity of a single battery pack in the energy storage battery). At this time, battery pack 3 and battery pack 2 will supply power simultaneously, and both battery pack 3 and battery pack 2 output at the maximum allowable power of 2.5 kW, which just meets the power demand of the electrical load. When the real-time capacity of battery pack 3 drops to 195AH and it still needs to be supplied with an output power of 5KW, battery pack 2 operates at the maximum allowable output power of 2.5KW, and the remaining power (2.5KW) is evenly shared by battery pack 1, battery pack 3 and battery pack 4. This continues until the real-time capacity of the four battery packs is balanced and reaches 195AH, achieving capacity balance for each battery pack in the energy storage battery, and then further achieving equal current output control of the energy storage battery through the method of Example 1 or Example 2.

[0472] Example 4:

[0473] This embodiment describes a current sharing control system for energy storage batteries. As shown in FIG22 , the energy storage battery includes multiple battery packs connected in parallel. The battery packs are connected to an energy storage converter after being connected in parallel. The output end of the energy storage converter is connected to an electrical load for supplying power to the electrical load. A DC conversion module is provided in each battery pack. The output end of the battery pack is connected to the DC conversion module, which is then connected to the energy storage converter. The energy storage converter determines the intended output current Current(i) according to the energy storage battery current sharing control method of Example 1, and controls the output voltage of the DC conversion module according to the intended output current Current(i).

[0474] Example 5:

[0475] This embodiment describes a current sharing control system for energy storage batteries. As shown in FIG23 , the energy storage battery includes multiple battery packs connected in parallel. The battery packs are connected to an energy storage converter after being connected in parallel. The output end of the energy storage converter is connected to an electrical load for supplying power to the electrical load. A DC conversion module and a temperature sensor are provided in each battery pack. The output end of the battery pack is connected to the DC conversion module, which is then connected to the energy storage converter. The data output end of the temperature sensor is connected to the DC conversion module in the battery pack. The energy storage converter determines the output current Current'(i) according to the energy storage battery current sharing control method of Example 2, and controls the output voltage of the DC conversion module according to the intended output current Current(i).

[0476] The present application also provides a computer medium executed by a data processing device, wherein the data processing device has a processor containing program code. When executing the program code, the processor executes the aforementioned energy storage battery current sharing control method.

[0477] The energy storage battery current sharing control system constructed based on the above method has a simple overall architecture and can adapt to the installation and mixed use of new and old battery packs or battery packs of different models, reducing the workload of installers.

[0478] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in the opposite order according to the functions involved. For example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0479] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0480] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

[0481] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0482] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A battery cluster balancing control method, characterized in that: The battery cluster includes at least one PACK, and the PACK includes at least one battery cell; the method includes: Acquire at least one of a first actual state of charge and an actual state of health of each of the battery cells, and a second actual state of charge of each of the PACKs; Based on at least one of the first actual state of charge and the actual state of health, controlling at least one of state of charge balancing and state of health balancing of each of the battery cells through a first balancing module; Based on the second actual state of charge, controlling the state of charge balancing of the PACK through a second balancing module; The first balancing module and the second balancing module are connected to the PACK respectively.

2. The battery cluster balancing control method according to claim 1, characterized in that: The first balancing module includes a first sub-balancing module, and the first balancing module controls at least one of the state of charge balancing and the state of health balancing of each battery cell based on at least one of the first actual state of charge and the actual state of health, including: When the difference between the first actual state of charge of a first target battery cell and the first actual state of charge of a first lowest cell among the at least one battery cell is greater than a first preset value, the first sub-balancing module is adjusted to balance the state of charge of the first target battery cell; wherein the first lowest cell is the battery cell with the lowest first actual state of charge among the at least one battery cell.

3. The battery cluster balancing control method according to claim 2, characterized in that: The first sub-balancing module includes at least one first switch connected in parallel with the at least one battery cell in a one-to-one correspondence, and a first resistor arranged between the first switch and the battery cell connected in parallel with the first switch; The adjusting the first sub-balancing module to balance the state of charge of the first target battery cell includes: Controlling a first switch connected in parallel with the first target battery cell to close; When the difference between the first actual state of charge of the first target battery cell and the first actual state of charge of the first lowest cell is less than a second preset value, the first switch connected in parallel with the first target battery cell is controlled to be disconnected, and the second preset value is less than the first preset value.

4. The battery cluster balancing control method according to any one of claims 1 to 3, characterized in that: The first balancing module includes a second sub-balancing module, and the first balancing module controls at least one of the state of charge balancing and the state of health balancing of each battery cell based on at least one of the first actual state of charge and the actual state of health, including: When the difference between the actual health state of the first highest cell and the actual health state of the second lowest cell is greater than a third preset value, the second sub-balancing module is adjusted to balance the health state of the second lowest cell; wherein the first highest cell is the cell with the highest actual health state among the at least one battery cell. The second lowest cell is a battery cell with the lowest actual health state among the at least one battery cell.

5. The battery cluster balancing control method according to claim 4, characterized in that: The second sub-balancing module includes at least one electromagnetic induction module arranged in one-to-one correspondence with the at least one battery cell, the first end of the electromagnetic induction module is connected to the positive electrode of the battery cell, the second end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a second resistor and a second switch connected in series, the third end of the electromagnetic induction module is connected to the positive electrode of the battery cell, and the fourth end of the electromagnetic induction module is connected to the negative electrode of the battery cell via a third resistor and a third switch connected in series; The adjusting the second sub-balancing module to balance the health status of the second lowest cell includes: The second switch and the third switch corresponding to the second lowest cell are controlled to be closed in sequence.

6. The battery cluster balancing control method according to any one of claims 1 to 5, characterized in that: The controlling the charge state balancing of the PACK by a second balancing module based on the second actual charge state includes: When the difference between the second actual state of charge of the first target PACK and the second actual state of charge of the lowest PACK in the at least one PACK is greater than a fourth preset value, the second balancing module is adjusted to balance the state of charge of the first target PACK; wherein the lowest PACK is the PACK with the lowest second actual state of charge in the at least one PACK.

7. The battery cluster balancing control method according to claim 6, characterized in that: The second balancing module includes a fourth resistor and a fourth switch connected in series, and the fourth resistor and the fourth switch connected in series are connected in parallel with the PACK; The adjusting the second balancing module to balance the state of charge of the first target PACK includes: Controlling a fourth switch corresponding to the first target PACK to be closed; After a first target time period, a fourth switch corresponding to the first target PACK is controlled to be disconnected.

8. The battery cluster balancing control method according to claim 7, characterized in that: The first target duration is determined based on the following steps: The first target duration is calculated based on the second actual state of charge of the first target PACK, the second actual state of charge of the lowest PACK, the nominal capacity of the battery, the battery aging degree of the first target PACK, the voltage value across the first target PACK and the resistance value of the fourth resistor.

9. The battery cluster balancing control method according to claim 7, characterized in that: Also includes: When there is at least one battery cell in the first target PACK whose cell voltage is less than a sixth preset value, the branch where the fourth resistor and the fourth switch connected in series in parallel with the first target PACK are located is controlled to be disconnected.

10. The battery cluster balancing control method according to any one of claims 1 to 9, characterized in that: Also includes: When the actual temperature of the second balancing module is greater than the fifth preset value, the second balancing module is cooled. Hot operation.

11. A battery cluster balancing control device, characterized in that: The battery cluster includes at least one PACK, and the PACK includes at least one battery cell; the device includes: A first processing module, configured to obtain at least one of a first actual state of charge and an actual health state of each of the battery cells, and a second actual state of charge of each of the PACKs; A second processing module, configured to control at least one of state of charge balancing and health state balancing of each of the battery cells through a first balancing module based on at least one of the first actual state of charge and the actual health state; A third processing module, configured to control the charge state balancing of the PACK through a second balancing module based on the second actual charge state; The first balancing module and the second balancing module are connected to the PACK respectively.

12. A system based on the battery cluster balancing control method according to any one of claims 1 to 10, characterized in that: include: Battery management unit; A first balancing module, connected to the battery management unit and the PACK respectively; The second balancing module is connected to the battery management unit and the PACK respectively.

13. The system according to claim 12, characterized in that The first balancing module includes at least one of a first sub-balancing module and a second sub-balancing module, wherein: The first sub-balancing module is integrated into the battery management unit; The second sub-equalizing module is integrated into the PACK or arranged outside the system.

14. The system according to claim 12 or 13, characterized in that In the case where the second balancing module includes a fourth resistor and a fourth switch connected in series, and the fourth resistor and the fourth switch connected in series are connected in parallel with the PACK, the second balancing module further includes: a fifth switch, the fifth switch being connected in series with the fourth switch; A voltage protection circuit is electrically connected to the PACK and the fifth switch respectively, and is used to control the on / off state of the fifth switch based on the cell voltage of each of the battery cells in the PACK.

15. The system according to any one of claims 12 to 14, characterized in that: The second balancing module further includes: A temperature sensor, wherein the temperature sensor is used to collect the actual temperature of the second balancing module; A heat sink is connected to the positive electrode of the PACK corresponding to the second balancing module, and a switching state of the heat sink is controlled based on the actual temperature.

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