Battery pack energy equalization methods, systems, devices, and media

Abstract

The application relates to a battery pack energy equalization method, system, device and medium. The method comprises the following steps: acquiring data of each battery pack, wherein the data of each battery pack comprises a health degree, a state of charge, a battery temperature and a rated power; dividing each battery pack into a health group and an aging group based on the health degree; determining a working limit power value of each battery pack based on the battery temperature and the rated power of each battery pack; if the sum of the working limit power values of the battery packs in the health group is greater than or equal to a total target power, distributing the total target power to each battery pack in the health group according to the working limit power value and the state of charge of each battery pack in the health group; otherwise, the power distributed to each battery pack in the health group is the working limit power value, and the remaining power is distributed to each battery pack in the aging group according to the working limit power value and the state of charge of each battery pack in the aging group. The method can accurately control the energy difference between the battery packs.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery pack energy balancing method, system, device and medium. Background Technology

[0002] With increasing global awareness of clean energy and the continuous decline in lithium battery costs, photovoltaic energy storage systems are entering a phase of rapid development. In a complete energy storage system, batteries, as the core component, are typically connected to the energy storage inverter in multiple series / parallel configurations to meet practical application requirements. However, due to differences in manufacturing processes, operating environments, and temperature distribution, inconsistencies (i.e., imbalances) in parameters such as state of charge (SOC) and voltage inevitably occur between individual cells or clusters during charge-discharge cycles. This imbalance significantly reduces the overall usable capacity of the battery pack, shortens its lifespan, increases the risk of thermal runaway, and affects the system's output power. In large-scale industrial and commercial energy storage systems, an architecture is often adopted where multiple independent battery packs are equipped with independent bidirectional DC-DC converters connected in parallel to inverters for grid connection or load driving. The problem of imbalance between battery packs is particularly prominent in this architecture.

[0003] To address the issue of battery imbalance in industrial and commercial energy storage systems, the current main approach is passive balancing: a resistor switch is connected in parallel across each battery pack, and balancing is achieved by dissipating the energy of high-energy (high voltage / high SOC) single clusters as heat.

[0004] However, while this solution has a lower system setup cost, it wastes electrical energy by dissipating energy through heat, and it is difficult to accurately control the energy difference between clusters, resulting in low equalization efficiency. In addition, the equalization process releases a large amount of heat, bringing additional heat dissipation burden and thermal management design challenges, posing a significant threat to the system's environmental safety.

[0005] Therefore, there is an urgent need for a balancing method that can precisely control the energy difference between battery packs. Summary of the Invention

[0006] Therefore, it is necessary to provide a battery pack energy balancing method, system, device, and medium that can accurately control the energy difference between clusters, in order to address the above-mentioned technical problems.

[0007] In a first aspect, this application provides a battery pack energy balancing method, the method comprising:

[0008] Data for each battery pack is acquired, including health status, state of charge, battery temperature, and rated power.

[0009] Based on the health status of each battery pack, each battery pack is divided into a healthy group and an aging group;

[0010] Based on the battery temperature and rated power of each battery pack, the operating limit power value of each battery pack is determined;

[0011] If the sum of the operating limit power values ​​of each battery pack in the health group is greater than or equal to the total target power, the total target power is allocated to each battery pack in the health group according to the operating limit power value and the state of charge of each battery pack in the health group.

[0012] If the sum of the operating limit power values ​​of each battery pack in the healthy group is less than the total target power, the power allocated to each battery pack in the healthy group is the operating limit power value. Based on the operating limit power values ​​and state of charge of each battery pack in the aging group, the remaining power is allocated to each battery pack in the aging group. The remaining power is the total target power minus the total allocated power, where the total allocated power is the sum of the power allocated to all battery packs in the healthy group.

[0013] In one embodiment, classifying the battery packs into a healthy group and an aging group based on their health status includes:

[0014] If the maximum health difference in each battery pack is greater than or equal to the health difference threshold, the battery packs with a health difference greater than or equal to the health difference threshold are classified into the aging group, and the battery packs with a health difference less than the health difference threshold are classified into the healthy group.

[0015] The maximum health difference is the difference between the maximum and minimum health of each battery pack, and the health difference of each battery pack is the difference between the maximum health of each battery pack and the health of each battery pack itself.

[0016] In one embodiment, determining the maximum permissible power value of each battery pack based on the battery temperature and rated power of each battery pack includes:

[0017] Based on the set over-temperature threshold, the rated power of each battery pack, and the actual operating temperature of each battery pack, the temperature power limit of each battery pack is determined.

[0018] Based on the rated power limit and temperature power limit of each battery pack, the operating limit power value of each battery pack is determined.

[0019] In one embodiment, determining the temperature power limit for each battery pack based on a set over-temperature threshold, the rated power of each battery pack, and the actual operating temperature of each battery pack includes:

[0020] The temperature ratio of each battery pack is determined based on the ratio of the allowable temperature difference to the actual temperature difference of each battery pack. The actual temperature difference is the difference between the over-temperature threshold and the actual operating temperature. The allowable temperature difference is the allowable temperature gap from the over-temperature threshold.

[0021] Based on the temperature ratio of the battery pack and the rated power of the battery pack, the power difference limit of the battery pack is determined;

[0022] The temperature power limit of the battery pack is determined based on the rated power of the battery pack and the power difference limit of the battery pack.

[0023] In one embodiment, a target group is set as the healthy group or the aging group, and a target execution power is set as the total target power or the remaining power; the target execution power is allocated to each battery pack of the target group according to the operating limit power value and the state of charge of each battery pack in the target group, including:

[0024] Based on the state of charge of all battery packs in the target group, determine whether the energy of each battery pack in the target group is balanced;

[0025] If the energy is balanced, the target execution power is allocated to each target battery pack in the target group based on the operating limit power value of each battery pack in the target group and the state of charge.

[0026] Otherwise, based on the state of charge of all battery packs in the target group, the target group is divided into an equalized group and an unbalanced group, and the target execution power is allocated to the equalized group and the unbalanced group respectively.

[0027] In one embodiment, the step of allocating the target execution power to each target battery pack in the target group based on the operating limit power value of each battery pack in the target group and the state of charge if energy is balanced includes:

[0028] If the energy is balanced, a first reference power for each battery pack in the target group is determined based on the ratio of the states of charge of each battery pack in the target group and the target execution power.

[0029] When the first reference power is greater than or equal to the operating limit power value of the battery pack, the operating limit power value is allocated to the battery pack;

[0030] When the first reference power is less than the operating limit power value of the battery pack, the first reference power is allocated to the battery pack.

[0031] In one embodiment, the allocation of the target execution power to the balanced group and the unbalanced group respectively includes:

[0032] If the sum of the operating limit power values ​​of each battery pack in the equalization group is greater than or equal to the target execution power, the power allocation of each battery pack in the equalization group is determined according to the proportion of the state of charge of each battery pack in the equalization group and the target execution power.

[0033] If the sum of the maximum power of each battery pack in the equalization group is less than the target execution power, and the sum of the working limit power values ​​of each battery pack in each equalization group and unbalanced group is greater than or equal to the target execution power, the working limit power value is allocated to each battery pack in the equalization group. A first power to be allocated is determined based on the working limit power value of each battery pack in each equalization group and the target execution power. The first power to be allocated is allocated to each battery pack in each unbalanced group based on the size ratio of the state of charge of each battery pack in each unbalanced group and the first power to be allocated.

[0034] If the sum of the operating limit power values ​​of each battery pack in each of the balanced and unbalanced groups is less than the target execution power, the operating limit power values ​​are allocated to each battery pack in each of the balanced and unbalanced groups.

[0035] In one embodiment, a reference group is set as an equalized group or an unbalanced group, and the power to be allocated is set as the target execution power or a first power to be allocated; the method further includes:

[0036] Determine whether the sum of the allocated power corresponding to each battery pack in the reference group is less than the power to be allocated;

[0037] If the sum of the allocated power of each battery pack in the reference group is less than the power to be allocated, the battery packs in the reference group are divided into a full-power operation group and a non-full-power operation group based on the allocated power of each battery pack in the reference group and the working limit power value, wherein the allocated power of the battery pack in the full-power operation group is equal to the working limit power value.

[0038] Based on the allocated power of each battery pack in the full-power operation group and the power to be allocated, the second power to be allocated is determined;

[0039] Based on the proportion of the state of charge of each battery pack in the non-full power operation group and the second power to be allocated, the second reference power of each battery pack in the non-full power operation group is determined.

[0040] When the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is greater than or equal to the working limit power value of the battery pack, the new allocated power of the battery pack in the non-full power operation group is determined as the working limit power value, and the battery pack in the non-full power operation group is assigned to the full power operation group.

[0041] When the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is less than the operating limit power value of the battery pack, the new allocated power of the battery pack is determined to be the sum of the second reference power and the allocated power, and the step of determining whether the sum of the allocated power of each battery pack in the reference group is less than the power to be allocated continues until the sum of the allocated power of each battery pack in the reference group is equal to the power to be allocated.

[0042] In one embodiment, determining whether the battery packs within the target group are energy-balanced based on the state of charge of all battery packs in the target group includes:

[0043] Obtain the maximum value of the state of charge of all battery packs within the target group;

[0044] Obtain the minimum state of charge of all battery packs within the target group;

[0045] Calculate the charge difference between the maximum and minimum values;

[0046] If the charge difference is less than or equal to a preset threshold, then the battery packs in the target group are in energy balance.

[0047] If the charge difference is greater than the preset threshold, then the battery packs in the target group are energy-uneven.

[0048] Secondly, this application also provides a battery pack energy balancing system, the system comprising:

[0049] Each battery pack;

[0050] Each bidirectional DC module has its positive and negative terminals connected to a battery pack via a contactor, and its positive and negative terminals are connected to a busbar.

[0051] A battery equalizer, wherein the first port of the battery equalizer is communicatively connected to each of the bidirectional DC modules, and the second port of the battery equalizer is communicatively connected to each of the battery packs; the battery equalizer is used to perform the above-described battery pack energy balancing method.

[0052] Thirdly, this application also provides an energy storage device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method in any of the above embodiments.

[0053] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the methods in any of the above embodiments.

[0054] The aforementioned battery pack energy balancing method, system, equipment, and medium first divide the battery packs into healthy groups and aged groups based on their health status. Then, the operating limit power value of the battery packs is determined based on the battery temperature and rated power. When the sum of the operating limit power values ​​of the battery packs in the healthy group is greater than or equal to the total target power, the total target power is allocated to the battery packs in the healthy group only based on the operating limit power value and state of charge of each battery pack in the healthy group. When the battery packs in the healthy group cannot bear all the total target power, battery packs in the aged group are introduced to bear part of the total target power. In this way, the power is borne according to the health status to achieve energy balance among the battery packs. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0056] Figure 1 This is a block diagram of a battery pack energy balancing system in one embodiment;

[0057] Figure 2 This is a flowchart illustrating a battery pack energy balancing method in one embodiment;

[0058] Figure 3 A flowchart of a battery pack energy balancing method in another embodiment;

[0059] Figure 4 for Figure 3 A flowchart of a battery pack energy balancing method during mid-discharge;

[0060] Figure 5 This is an internal structural diagram of a computer device in one embodiment. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0062] It should be noted that the terms "first," "second," etc., used in this application can be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. The terms "comprising" and "having," and any variations thereof, used in this application, are intended to cover non-exclusive inclusion. The term "multiple" used in this application refers to two or more. The term "and / or" used in this application refers to one of the embodiments, or any combination of multiple embodiments.

[0063] Combination Figure 1 As shown, Figure 1 This is a block diagram of a battery pack energy balancing system in one embodiment. The battery pack energy balancing system includes: each battery pack, each bidirectional DC module, and a battery equalizer.

[0064] Each bidirectional DC module has its positive and negative terminals connected to a battery pack via a contactor, and each bidirectional DC module's positive and negative terminals are connected to the busbar. The first port of the battery equalizer is connected to each bidirectional DC module, and the second port of the battery equalizer is connected to each battery pack. The battery equalizer is used to execute a battery pack energy equalization method to achieve energy balance between battery packs.

[0065] The existing bidirectional DC modules in the system, which connect each battery pack to the common DC bus, serve as the actuators for energy transfer. No additional independent equalization circuit is needed. The working mode of each bidirectional DC module is directly controlled by the battery equalizer, which outputs voltage / current commands to realize the bidirectional flow of energy between the battery pack and the DC bus.

[0066] Figure 1 This example uses four battery packs; however, the number of battery packs can vary in other embodiments and is not specifically limited here. The positive and negative terminals of each battery pack are independently connected to the positive and negative terminals of the bidirectional DC module via power lines, and are protected by independent contactors K1 and K2, and are externally packaged into an independent cabinet. The positive and negative terminals of the four cabinets are connected in parallel to the positive and negative terminals of the energy storage inverter via power lines, forming a common DC bus. The communication architecture uses CAN bus communication. The CAN communication ports of the four bidirectional DC modules are all connected to the CAN1 port of the battery equalizer via communication lines; the CAN communication ports of the four battery packs are all connected to the CAN2 port of the battery equalizer via communication lines. The battery equalizer acquires data from the bidirectional DC module and the battery packs.

[0067] The battery equalizer can acquire data from each bidirectional DC module; based on the data from each bidirectional DC module and each battery pack, it determines the fault status of the bidirectional DC module and the battery pack; in the case of a battery pack failure, it determines the total target power based on the total power of the non-faulty battery packs, removes the faulty battery pack, and then executes the battery pack energy equalization method of this application.

[0068] The battery equalizer has the following functions:

[0069] Read battery pack data: maximum allowable charging power, maximum allowable discharging power, total battery voltage, total battery current, state of health (SOH), state of charge (SOC), battery temperature, and battery faults.

[0070] Send battery pack data: main contactor K1 engages / disengages, negative contactor K2 engages / disengages.

[0071] Read bidirectional DC module data: bidirectional DC voltage, bidirectional DC current, bidirectional DC temperature, and bidirectional DC fault.

[0072] Send bidirectional DC module data: bidirectional DC power-on / power-off command, bidirectional DC target power.

[0073] The battery equalizer can perform adaptive functions based on the number of faulty cabinets in the system. These functions include: calculating the total allowable charging / discharging power of normal batteries in the system and updating it to the current charging / discharging power rating of the system, i.e., automatic de-rating of the system; the battery equalizer reallocates the system topology configuration, removes the data of the faulty battery pack from the control vector, and recalculates the equalization target power based on the normal battery pack.

[0074] Optionally, in the event of a battery pack failure, a shutdown command is sent to the bidirectional DC module corresponding to the faulty battery pack. The shutdown command is used to instruct the bidirectional DC module corresponding to the battery pack to stop inputting or outputting power; or a shutdown command is sent to the bidirectional DC module corresponding to the faulty battery pack and a segmented contactor command is sent to the faulty battery pack. The segmented contactor command is used to instruct the faulty battery pack to disconnect from the bidirectional DC module.

[0075] In this embodiment, when the battery equalizer detects a serious fault (such as internal short circuit, thermal runaway risk, insulation failure, DC module failure, etc.) in any battery pack or its corresponding bidirectional DC module, it sends a shutdown command to the bidirectional DC module to stop input / output power, achieving "soft isolation". Optionally, the battery equalizer sends a "disconnect contactor" command to the faulty battery pack, controlling the disconnection of the main positive contactor K1 and the main negative contactor K2 between the battery pack and the bidirectional DC module, to ensure that "hard isolation" of the faulty battery pack can still be achieved when the bidirectional DC module fails.

[0076] In one exemplary embodiment, such as Figure 2 As shown, a battery pack energy balancing method is provided, which is applied to... Figure 1 Taking the battery equalizer in the example, the explanation includes the following steps S1 to S5. Wherein:

[0077] S1: Obtain data for each battery pack, including health status, state of charge, battery temperature, and rated power.

[0078] When the system powers on, the battery equalizer actively queries the CAN source addresses of the bidirectional DC module and the battery pack to see if they are numbered (the protocol data units follow the J1939 protocol). If not, the source addresses of the bidirectional DC module are numbered from 0x01 to 0x04, and the source addresses of the battery pack are numbered from 0x11 to 0x14. The battery equalizer reads and sends data to the devices based on their source addresses.

[0079] The battery equalizer can read battery pack data, including battery health (SOH), battery state of charge (SOC), battery temperature, and rated power.

[0080] S2: Based on the health status of each battery pack, divide each battery pack into a healthy group and an aging group.

[0081] In this application, the battery pack is divided into a healthy group and an aged group based on its health status, with different energy allocation priorities for the healthy group and the aged group. Optionally, in this embodiment, the aged group and the healthy group can be obtained based on the difference in the health status of the battery pack, and the energy allocation priority of the healthy group is higher than that of the aged group, that is, energy is allocated to the healthy group first, and then to the aged group.

[0082] S3: Determine the operating limit power value of each battery pack based on the battery temperature and rated power of each battery pack.

[0083] Since temperature affects the operating power limit of the battery pack, this application can determine the operating power limit of the battery pack based on the battery temperature and rated power. For example, if the battery temperature is less than or equal to the over-temperature threshold, the operating power limit of the battery pack is the rated power. If the battery temperature is greater than the over-temperature threshold, the operating power limit of the battery pack decreases as the temperature increases.

[0084] S4: If the sum of the working limit power values ​​of each battery pack in the healthy group is greater than or equal to the total target power, the total target power is allocated to each battery pack in the healthy group according to the working limit power value and state of charge of each battery pack in the healthy group.

[0085] S5: If the sum of the working limit power values ​​of each battery pack in the healthy group is less than the total target power, the power allocated to each battery pack in the healthy group is the working limit power value. Based on the working limit power values ​​and state of charge of each battery pack in the aging group, the remaining power is allocated to each battery pack in the aging group. The remaining power is the total target power minus the total allocated power, and the total allocated power is the sum of the power allocated to all battery packs in the healthy group.

[0086] In this application, if the sum of the operating limit power values ​​of each battery pack in the health group is greater than or equal to the total target power, then each battery pack in the health group shall bear the total target power, and the power borne by each battery pack in the health group shall be determined based on the operating limit power value and state of charge of the battery pack.

[0087] If the sum of the operating limit power values ​​of all battery packs in the healthy group is less than the total target power, then the battery packs in the healthy group alone cannot bear the entire total target power. Therefore, the battery packs in the aging group also need to bear part of the total target power. Furthermore, to ensure balanced energy distribution, after setting the allocated power of the battery packs in the healthy group to their operating limit power values, the remaining power mainly borne by the aging group is determined. This remaining power equals the total target power minus the allocated power of all battery packs in the healthy group. Then, based on the operating limit power values ​​and state of charge of the battery packs in the aging group, this remaining power is allocated to each battery pack in the aging group.

[0088] In this application, it can first be determined whether it is a charging process or a discharging process based on the total target power Paim. For example, if the total target power Paim is greater than zero, it is a discharging process, and if the total target power Paim is less than zero, it is a charging process.

[0089] During the discharge process, the operating power limit of each battery pack in each healthy group is first determined. Whether the sum is greater than or equal to the total target power Paim.

[0090] If the operating power limit of each battery pack in the healthy group If the sum of the values ​​is greater than or equal to the total target power Paim, then each battery pack in the healthy group will bear the total target power Paim. Based on the operating power limit and state of charge of each battery pack in the healthy group, the total target power will be allocated to each battery pack in the healthy group.

[0091] If the operating power limit of each battery pack in the healthy group If the sum of the values ​​is less than the total target power Paim, then the power needs to be distributed among the battery packs in the aging group. However, the power allocated to each battery pack in the healthy group is the operating limit power value. Based on the operating power limit of each battery pack in the healthy group The sum of these values ​​and the total target power are used to determine the remaining power as the power that the battery pack in the aging group needs to handle. This remaining power is... Then, based on the operating limit power value and state of charge of each battery pack in the aging group, the remaining power is distributed to each battery pack in the aging group.

[0092] During the charging process, the operating power limit of each battery pack in the healthy group is first determined. Is the sum less than or equal to the total target power Paim?

[0093] If the operating power limit of each battery pack in the healthy group If the sum is less than or equal to the total target power Paim, then each battery pack in the healthy group bears the total target power Paim. Based on the operating limit power value and state of charge of each battery pack in the healthy group, the total target power is allocated to each battery pack in the healthy group.

[0094] If the operating power limit of each battery pack in the healthy group If the sum of these values ​​exceeds the total target power Paim, then an aging group is needed to distribute the power. However, the power allocated to each battery pack in the healthy group is the operating limit power value. Based on the operating power limit of each battery pack in the healthy group The sum of these values ​​and the total target power are used to determine the remaining power as the power that the battery pack in the aging group needs to handle. This remaining power is... Then, based on the operating limit power value and state of charge of each battery pack in the aging group, the remaining power is distributed to each battery pack in the aging group.

[0095] The aforementioned battery pack energy balancing method first divides the battery packs into healthy and aged groups based on their health status. Then, it determines the operating limit power value of each battery pack based on its battery temperature and rated power. When the sum of the operating limit power values ​​of all battery packs in the healthy group is greater than or equal to the total target power, the total target power is allocated to the battery packs in the healthy group only based on their operating limit power values ​​and state of charge. If the battery packs in the healthy group cannot bear all the total target power, then battery packs from the aged group are introduced to bear part of the total target power, i.e., to bear the remaining power. In this way, power is borne according to health status to achieve energy balance among battery packs.

[0096] In some optional embodiments, for step S2, based on the health of each battery pack, the battery packs are divided into a healthy group and an aging group, including: if the maximum health difference in each battery pack is greater than or equal to a health difference threshold, the battery packs with a health difference greater than or equal to the health difference threshold are assigned to the aging group, and the battery packs with a health difference less than the health difference threshold are assigned to the healthy group; wherein, the maximum health difference is the difference between the maximum health and the minimum health of each battery pack, and the health difference of each battery pack is the difference between the maximum health of each battery pack and the health of each battery pack itself.

[0097] Specifically, if the maximum health difference in each battery pack is greater than or equal to the health difference threshold, the battery packs with a health difference less than or equal to the health difference threshold are classified into the healthy group; otherwise, they are classified into the aging group.

[0098] The maximum health difference is the difference between the maximum and minimum health of each battery pack.

[0099] For example , Let's consider the health status of battery pack x. At this point, the maximum health status is 99%, the minimum health status is 93%, and the difference is 6%, which is greater than the health status difference threshold of 5% (in other embodiments, it can be other values). Therefore, it is necessary to group the battery packs. To do this, we calculate the health status difference for each battery pack, that is, determine the difference between the health status of each battery pack and the maximum health status. Battery packs with a health status difference less than or equal to the health status difference threshold are assigned to the healthy group, and otherwise assigned to the aging group. Therefore, battery pack 4 can be assigned to the aging group, and the remaining battery packs can be assigned to the healthy group.

[0100] In this application, battery packs in the healthy group are allocated priority, therefore, the energy allocation priority of battery packs in the healthy group is higher than that of battery packs in the aged group. ,in Assign priority to battery pack x.

[0101] In some optional embodiments, for step S3, the operating limit power value of each battery pack is determined based on the battery temperature and rated power of each battery pack, including the following steps S31 to S32.

[0102] Step S31: Based on the set over-temperature threshold, the rated power of each battery pack, and the actual operating temperature of each battery pack, determine the temperature power limit of each battery pack.

[0103] Step S32: Determine the operating limit power value of each battery pack based on the rated power limit and temperature power limit of each battery pack.

[0104] When the actual operating temperature of the battery pack exceeds the over-temperature threshold, the temperature power limit of the battery pack is determined based on the rated power of the battery pack and the battery temperature of the battery pack; when the actual operating temperature of the battery pack is less than or equal to the over-temperature threshold, the temperature power limit of the battery pack is determined to be the rated power of the battery pack.

[0105] In some optional embodiments, for step S31, the temperature power limit of each battery pack is determined based on the set over-temperature threshold, the rated power of each battery pack and the actual operating temperature of each battery pack, including steps S311 to S313.

[0106] Step S311: Determine the temperature ratio of each battery pack based on the ratio of the allowable temperature difference to the actual temperature difference of each battery pack. The actual temperature difference is the difference between the over-temperature threshold and the actual operating temperature, and the allowable temperature difference is the allowable temperature gap from the over-temperature threshold.

[0107] Among them, the over-temperature threshold This is based on the battery's maximum temperature.

[0108] To allow for temperature difference, The value can be 10°. The battery temperature of the battery pack can be set according to specific circumstances to be close to the over-temperature threshold. Maximum temperature When the value is less than the safe interval, the battery pack is considered unsuitable for operation.

[0109] The actual temperature difference of the battery pack is the difference between the actual operating temperature of the battery pack and the over-temperature threshold, i.e. ,in The actual operating temperature of the battery pack is given by the temperature ratio of the battery pack. .

[0110] Step S312: Determine the power difference limit of the battery pack based on the temperature ratio of the battery pack and the rated power of the battery pack.

[0111] Specifically, the power difference limit for the battery pack is: ,in, This refers to the rated power of the battery pack.

[0112] Step S313: Determine the temperature power limit of the battery pack based on the rated power of the battery pack and the power difference limit of the battery pack.

[0113] Specifically, determine the rated temperature power limit for the battery pack. for:

[0114]

[0115] After determining the temperature power limit, the operating power limit of the battery pack is the lesser of the rated power limit and the temperature power limit.

[0116] The battery pack's operating power limit includes its discharge operating power limit. and charging operating power limit value This application determines the operating limit power value based on the rated power limit and temperature power limit of each healthy battery pack, as follows:

[0117] =MIN(Discharge rated power limit, )

[0118] =MIN(Charging rated power limit, )

[0119] In the above embodiments, the operating limit power value of the battery pack was determined based on the battery temperature and rated power of the battery pack, laying the foundation for subsequent energy distribution of the battery pack.

[0120] Whether the battery packs in the healthy group bear the entire total target power or the battery packs in the aging group bear the remaining power, it is necessary to determine whether the battery packs participating in the allocation are balanced based on their state of charge (SBC). Specifically, in step S4, the total target power is allocated to the battery packs in the healthy group based on their operating limit power value and SBC. Similarly, in step S5, the remaining power is allocated to the battery packs in the aging group based on their operating limit power value and SBC. Both steps require determining whether the battery packs are energy-balanced based on their SBC. In some optional embodiments, for ease of description, the target group is set to either the healthy group or the aging group, and the target execution power is set to either the total target power or the remaining power. That is, when the target group is the healthy group, the target execution power is the total target power; when the target group is the aging group, the target execution power is the remaining power.

[0121] Based on the operating power limit and state of charge (SPC) of each battery pack in the target group, the target execution power is allocated to each battery pack in the target group. This includes: determining whether the battery packs in the target group are energy-balanced based on the SPC of all battery packs in each target group; if energy is balanced, allocating the target execution power to each battery pack in the target group based on the operating power limit and SPC of each battery pack in the target group; otherwise, dividing each target group into a balanced group and an unbalanced group based on the SPC of all battery packs in the target group, and allocating the target execution power to the balanced group and the unbalanced group respectively.

[0122] Determining whether all battery packs within a target group are energy-balanced based on their state of charge (SOC) can be achieved by determining the difference between the maximum and minimum SOC of the battery packs within the target group. In some optional embodiments, determining whether the battery packs within the target group are energy-balanced based on their SOC includes: obtaining the maximum SOC of all battery packs within the target group; obtaining the minimum SOC of all battery packs within the target group; calculating the charge difference between the maximum and minimum SOC; if the charge difference is less than or equal to a preset threshold, the battery packs within the target group are energy-balanced; if the charge difference is greater than the preset threshold, the battery packs within the target group are energy-unbalanced.

[0123] Specifically, the charge difference is the difference between the maximum and minimum state of charge (SOC) values ​​of all battery packs within the target group. A preset threshold can be set according to actual conditions; for example, it can be 3%, or other values ​​in other embodiments. If the charge difference is less than or equal to the preset threshold, the battery packs within the target group are considered energy-balanced; otherwise, their energy is unbalanced. This application addresses the energy balance of each battery pack within the target group separately, specifically:

[0124] When the energy of the battery packs in each target group is balanced, the total target power is allocated to each battery pack in the target group based on the working limit power value and state of charge of each battery pack in the target group. For example, the total target power is allocated based on the proportion of the state of charge to balance the state of charge among the battery packs.

[0125] When the battery packs within the target group have uneven energy distribution, the battery packs within the target group are divided into balanced groups and unbalanced groups. The target execution power is then allocated to the balanced groups and unbalanced groups respectively. The allocation method of the target execution power is determined based on the relationship between the sum of the working limit power values ​​of each battery pack in the balanced group and the target execution power, and the relationship between the sum of the working limit power values ​​of each battery pack in each balanced group and unbalanced group and the target execution power. For details, please refer to the following text.

[0126] In some optional embodiments, if the energy is balanced, the target execution power is allocated to each target battery pack based on the operating limit power value and state of charge of each battery pack in the target group, including: if the energy is balanced, determining a first reference power for each battery pack in the target group based on the proportion of the state of charge of the battery packs in the target group and the target execution power; when the first reference power is greater than or equal to the operating limit power value of the battery pack, allocating the operating limit power value to the battery pack; when the first reference power is less than the operating limit power value of the target battery pack, allocating the first reference power to the battery pack.

[0127] With the battery packs within the target group operating at a balanced rate, the total target power is allocated to each battery pack within the target group based on the operating limit power value and the proportion of their state of charge (SOC). Specifically, if the first reference power determined based on the SOC proportion is greater than or equal to the operating limit power value, the operating limit power value is allocated to the battery pack; otherwise, the first reference power is allocated to the battery pack.

[0128] Specifically, this embodiment describes the battery packs in the healthy group during the discharge and charging processes respectively. The treatment of the battery packs in the aging group is similar and will not be repeated here.

[0129] For the discharge process, i.e., the total target power >0, resulting in equation A:

[0130]

[0131] in, Let be the first reference power calculated during the discharge process, and if ,but ,otherwise ,in This refers to the power allocated to each battery pack within the healthy group during the discharge process.

[0132] For the charging process, i.e., the total target power <0, we get equation B:

[0133]

[0134] in, Let be the first reference power calculated during the discharge process, and if ,but ,otherwise . This refers to the power allocated to each battery pack within the healthy group during the discharge process.

[0135] In some optional embodiments, the target execution power is allocated to the balanced group and the unbalanced group respectively, including: when the sum of the working limit power values ​​of the balanced group is greater than or equal to the target execution power, determining the allocated power of each battery pack in the balanced group based on the proportion of the state of charge of each battery pack in the balanced group and the target execution power; when the sum of the working limit power values ​​of each battery pack in the balanced group is less than the target execution power, and the sum of the working limit power values ​​of each battery pack in the balanced group and the unbalanced group is greater than or equal to the target execution power, determining the allocated power of each battery pack in the balanced group as the working limit power value of each battery pack in the balanced group, determining a first power to be allocated based on the target limit power value of each battery pack in the unbalanced group and the target execution power, and allocating the first power to be allocated to each battery pack in the unbalanced group based on the proportion of the state of charge of each battery pack in the unbalanced group and the first power to be allocated; when the sum of the working limit power values ​​of each battery pack in the balanced group and the unbalanced group is less than the target execution power, allocating the working limit power value to each battery pack in the balanced group and the unbalanced group.

[0136] In cases of imbalanced battery packs within target groups, first determine whether each battery pack in the balanced group can fully bear the target execution power. If so, then each battery pack in the balanced group will bear the full power, for example, according to the proportion of the state of charge of each battery pack in the balanced group and the working limit power value of the battery pack. A third reference power can be determined by combining Equation A or Equation B (i.e., replacing the battery packs in the healthy group in Equation A or Equation B with the battery packs in the balanced group, and changing the total target power in Equation A or Equation B). If the target execution power is changed, and the third reference power of the battery pack in the equalization group is greater than or equal to the working limit power value, then the working limit power value will be allocated to the battery pack; otherwise, the third reference power will be allocated to the battery pack. The battery packs in the unbalanced group will not participate in energy distribution.

[0137] If the power exceeds the capacity of each battery pack in the balancing group, the operating limit power value is allocated to each battery pack in the balancing group. The first power to be allocated that exceeds the capacity of each battery pack in the balancing group is redistributed by the battery packs in the unbalancing group. The redistribution process of the battery packs in the unbalancing group can still be based on the proportion of the state of charge of each battery pack in the unbalancing group and the operating limit power value of the battery pack. Combining the above formula A or B, the fourth reference power can be determined (that is, replacing the battery packs in the healthy group in formula A or B with the battery packs in the unbalancing group, and changing the total target power in formula A or B). If the power to be allocated is changed to the first power to be allocated, and the fourth reference power is greater than or equal to the working limit power value, then the working limit power value is allocated to each battery pack in the unbalanced group; otherwise, the fourth reference power is allocated to each battery pack in the unbalanced group.

[0138] Furthermore, if the sum of the operating limit power values ​​of each battery pack in the balanced group and the unbalanced group is less than the target execution power, that is, the target execution power exceeds the capacity of all battery packs, then the operating limit power values ​​will be allocated to each battery pack in each balanced group and the unbalanced group.

[0139] To facilitate understanding, the discharge process is used as an example. Given the uneven energy distribution among the battery packs in the target group, it is determined whether each battery pack in the equalization group can handle the target power. If the battery packs in the equalization group can handle the target power, the energy is allocated according to the following formula:

[0140]

[0141] like ,but ,otherwise .in, This is the third reference power during the discharge process. The power allocated to the x-th battery pack in the equalization group, The target power to be executed during the discharge process.

[0142] If the battery packs within the equalization group cannot handle the full target execution power, then the power allocated to the battery packs within the equalization group is the operating limit power value, i.e. And obtain the first power to be allocated during the discharge process. = Then allocate according to the following formula:

[0143]

[0144] like ,but ,otherwise, .in, This is the fourth reference power during the discharge process. This represents the power allocated to the x-th battery pack in the unbalanced group.

[0145] Furthermore, if the target power exceeds the discharge capacity of all battery packs, the power allocated to the battery packs in the equalization group and the battery packs in the unbalanced group will both be the operating limit power value, and the system will discharge at limited power.

[0146] During the charging process, if the energy of the battery packs in each target group is uneven, first determine whether each battery pack in the equalization group can fully bear the target execution power. If the battery packs in the equalization group can bear the target execution power, then the power is allocated according to the following formula:

[0147]

[0148] like ,but , .in, This is the third reference power during the charging process. To allocate power to the x-th battery pack in the equalization group, The target power to be achieved during the charging process.

[0149] If the battery packs within the equalization group cannot handle the full target execution power, then the power allocated to the battery packs within the equalization group is the operating limit power value, i.e. And obtain the first power to be allocated during the charging process. = Then allocate according to the following formula:

[0150]

[0151] And if ,but ,otherwise .in, This is the fourth reference power during the charging process. To allocate power to the x-th battery pack in the unbalanced group.

[0152] Furthermore, if the target power exceeds the charging capacity of all battery packs, the power allocated to the battery packs in the equalization group and the battery packs in the unbalanced group will be the operating limit power value, and the system will charge with limited power.

[0153] In some optional embodiments, when allocating power to balanced and unbalanced groups, the existence of the working limit power value may cause the sum of the final allocated power to be less than the power to be allocated. Therefore, the issue of reallocation needs to be considered. The method for determining whether balanced and unbalanced groups need to be reallocated is similar. In this application, for the sake of simplifying the description, the reference group is set as a balanced group or an unbalanced group, and the power to be allocated is set as the target execution power or the first power to be allocated. That is, when the reference group is a balanced group, the power to be allocated is the target execution power, and when the reference group is an unbalanced group, the power to be allocated is the first power to be allocated.

[0154] Optionally, the battery pack energy balancing method further includes: determining whether the sum of the allocated power corresponding to each battery pack in each reference group is less than the power to be allocated; if the sum of the allocated power corresponding to each battery pack in each reference group is less than the power to be allocated, dividing each battery pack in the reference group into a full-power operation group and a non-full-power operation group based on the allocated power corresponding to each battery pack in each reference group and the operating limit power value, wherein the allocated power of the battery pack in the full-power operation group is equal to the operating limit power value; determining a second power to be allocated based on the allocated power of each battery pack in the full-power operation group and the power to be allocated; and determining the power to be allocated for each battery pack in each non-full-power operation group based on the proportion of the state of charge of each battery pack in each non-full-power operation group and the second power to be allocated. The second reference power of the battery pack; when the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is greater than or equal to the working limit power value of the battery pack, the new allocated power of the battery pack in the non-full power operation group is determined as the working limit power value, and the battery pack in the non-full power operation group is assigned to the full power operation group; when the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is less than the working limit power value of the battery pack, the new allocated power of the battery pack in the non-full power operation group is determined as the second reference power and the sum of the allocated power, and the step of determining whether the sum of the allocated power corresponding to each battery pack in the reference group is less than the power to be allocated continues until the sum of the allocated power corresponding to each reference battery pack is equal to the power to be allocated.

[0155] Among these, when allocating the corresponding power to the battery pack, due to the existence of constraints, namely during the discharge process, if ,but Or during the charging process if ,but ,in The power allocated to the battery packs may be less than the total power to be allocated. For example, if the battery packs in each target group are balanced, the sum of the allocated power allocated to the battery packs in the target group may be less than the total target power. Or, when energy is allocated to the battery packs in an unbalanced group, if the sum of the allocated power allocated to the battery packs in the unbalanced group is less than the first power to be allocated, then a reallocation is required.

[0156] To address this, a full-power operation group and a non-full-power operation group are introduced. In the full-power operation group, the allocated power of the battery pack is equal to the operating limit power value, while in the non-full-power operation group, the allocated power of the battery pack is less than the operating limit power value.

[0157] Based on the allocated power and the power to be allocated of each battery pack in the full-power operation group, the second power to be allocated is determined. That is, the second power to be allocated is equal to the power to be allocated minus the target value, which is the sum of the allocated power of each battery pack in the full-power operation group.

[0158] For non-full-power operation groups, the second reference power of the battery packs in the non-full-power operation group is determined based on the proportion of the state of charge of the non-full-power operation group and the second power to be allocated. Specifically, for the discharge process: Here, ΔP3 is the second power to be allocated. This is the second reference power. For the charging process... .

[0159] Then determine whether the sum of the second reference power and the allocated power of the battery pack is greater than or equal to the working limit power value of the battery pack. If so, the new allocated power of the battery pack is the working limit power value, and at this time the battery pack can no longer bear other power, so the battery pack is moved from the non-full power operation group to the full power operation group.

[0160] If the sum of the second reference power and the allocated power of the battery pack is less than the operating limit power value of the battery pack, then the new allocated power of the battery pack at this time is the sum of the second reference power and the allocated power of the battery pack. Since the battery pack can still bear other power, the battery pack is still classified as a non-full power operation group.

[0161] Furthermore, after each power redistribution of the battery packs in the non-full-power operation group is completed, it is necessary to determine whether the sum of the allocated power of each battery pack in the reference group is equal to the power to be allocated. If so, the allocation is completed; otherwise, the power of each battery pack in the non-full-power operation group is redistributed again.

[0162] In the above embodiments, considering the issue of the working power limit of the battery pack, the sum of the allocated power of each battery pack in the final allocation is less than the power to be allocated. Therefore, it is necessary to redistribute the power to improve the accuracy of the allocation.

[0163] In order to facilitate understanding, the combination Figures 3 to 4 As shown, where Figure 3 Here is a flowchart of a battery pack energy balancing method in another embodiment. Figure 4 for Figure 3 The flowchart shows the battery pack energy balancing method during the discharge process. The judgment during the charging process is similar and will not be repeated here.

[0164] In this embodiment, the system relies on a battery equalizer to acquire data information from the bidirectional DC modules and battery packs, and to determine the fault status of the bidirectional DC modules and battery packs in real time. "Soft isolation" and "hard isolation" are implemented for faulty battery packs, while active equalization of input / output power is performed only on normal battery packs. Specifically, the battery equalizer acquires data from all bidirectional DC modules and battery packs, and then determines whether there are faults in the bidirectional DC modules and battery packs based on this data. If a fault exists, the battery equalizer issues a shutdown command to the corresponding rack's bidirectional DC module and / or a contactor shutdown command to the corresponding rack's battery pack. The bidirectional DC module responds to the shutdown command, stopping input and output, and the battery pack responds by shutting down contactors K1 and K2. The bidirectional DC module and battery pack complete the isolation action, the equipment data in the faulty rack is removed, and the total target power is determined based on the total power of the non-faulty battery packs.

[0165] Then, the battery equalizer divides the battery packs into healthy and unhealthy groups based on the health status of each battery pack; and determines the operating limit power value of each battery pack based on the battery temperature and rated power of each battery pack.

[0166] And determine whether the system is in the discharge or charging process based on the total target power.

[0167] For the discharge process (the charging process is similar and will not be described in detail here): First, determine the operating power limit of each battery pack in the healthy group. The sum of the values ​​is checked against the total target power Paim. If the sum is greater than or equal to the total target power Paim, then the battery packs in the healthy group bear the total target power Paim. Then, it is determined whether the energy of each battery pack in the healthy group is balanced. If the energy of each battery pack in the healthy group is balanced, then power is allocated to each battery pack in the healthy group according to the above formula A. Furthermore, if the sum of the allocated power of each battery pack in the healthy group is less than the total target power Paim, a reallocation is required. This involves determining the full-power operation group and the non-full-power operation group. Based on the allocated power of each battery pack in the full-power operation group and the total target power Paim, the second power to be allocated for the non-full-power operation group is determined. For the non-full-power operation group, based on the second power to be allocated and the state of charge, the second reference power of each battery pack in the non-full-power operation group is determined. Finally, it is determined whether the sum of the second reference power and the allocated power of the battery pack in the non-full-power operation group is greater than the working limit power value. If so, the battery pack in the non-full-power operation group is moved to the full-power operation group, and its corresponding allocated power is determined as the working limit power value. Then, it continues to determine whether the sum of the allocated power of each battery pack in the healthy group is less than the total target power Paim, until the sum of the allocated power of each battery pack in the healthy group equals the total target power.

[0168] If the total target power Paim can be achieved by discharging all the battery packs in the balanced group within the healthy group, then the power allocation of the battery packs in the balanced group within the healthy group is determined based on the state of charge and the operating power limit value, and the battery packs in the unbalanced group do not discharge.

[0169] If the total target power Paim exceeds the discharge capacity of each battery pack in the balanced group within the healthy group, then the power allocated to the battery packs in the balanced group within the healthy group is the operating limit power value. The first power to be allocated that exceeds the discharge capacity of the balanced group is redistributed by the battery packs in the unbalanced group, specifically determined based on the state of charge and operating limit power value of the battery packs in the unbalanced group.

[0170] If the sum of the allocated power of each battery pack in the balanced group of each health group is less than the first power to be allocated, then a reallocation is required. That is, a full-power operation group and a non-full-power operation group are determined. Based on the allocated power of each battery pack in the full-power operation group and the first power to be allocated, the second power to be allocated for the battery pack in the non-full-power operation group is determined. For the battery pack in the non-full-power operation group, the second reference power is determined based on the second power to be allocated and the allocated power. Finally, it is determined whether the sum of the second reference power and the allocated power of the battery pack in the non-full-power operation group is greater than the working limit power value. If so, the battery pack in the non-full-power operation group is moved to the full-power operation group, and its corresponding allocated power is determined as the working limit power value. Then, it is determined that the sum of the allocated power of each battery pack in each health group is less than the first power to be allocated, until the sum of the allocated power of each battery pack in each health group is equal to the first power to be allocated.

[0171] If the total target power Paim exceeds the discharge capacity of all battery packs, then the power allocated to each battery pack will be the operating limit power value, and the system will discharge at limited power.

[0172] If the sum of the operating limit power values ​​of each battery pack in the healthy group is less than the total target power Paim, then the battery packs in the aging group will share part of the total target power Paim. The power allocated to each battery pack in the healthy group is equal to the operating limit power value, and the power allocated to each battery pack in the aging group is the total target power Paim minus the sum of the power allocated to each battery pack in the healthy group.

[0173] Next, determine whether the energy of each battery pack in the aging group is balanced. Based on whether the energy of the battery packs in the aging group is balanced, the energy is allocated. For the specific method, please refer to the allocation process of the healthy battery pack, which will not be repeated here.

[0174] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages in other steps. It is understood that the steps in different embodiments can be freely combined as needed, and all non-contradictory solutions formed by such combinations are within the scope of protection of this application.

[0175] In one exemplary embodiment, an energy storage device is provided, the computer device being a server, and its internal structure diagram being as shown below. Figure 5 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores the data involved in the aforementioned methods. The I / O interfaces are used for exchanging information between the processor and external devices. The communication interface is used for communicating with external terminals via a network connection. When the computer program is executed by the processor, it implements a battery pack energy balancing method.

[0176] Those skilled in the art will understand that Figure 5 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0177] In one embodiment, an energy storage device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0178] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon that, when executed by a processor, implements the steps in the above method embodiments.

[0179] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above method embodiments.

[0180] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0181] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0182] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A battery pack energy balancing method, characterized in that, The method includes: Data for each battery pack is acquired, including health status, state of charge, battery temperature, and rated power. Based on the health status of each battery pack, each battery pack is divided into a healthy group and an aging group; Based on the battery temperature and rated power of each battery pack, the operating limit power value of each battery pack is determined; If the sum of the operating limit power values ​​of each battery pack in the healthy group is greater than or equal to the total target power, the total target power is allocated to each battery pack in the healthy group according to the operating limit power value and the state of charge of each battery pack in the healthy group; If the sum of the operating limit power values ​​of each battery pack in the healthy group is less than the total target power, the power allocated to each battery pack in the healthy group is the operating limit power value. Based on the operating limit power values ​​and state of charge of each battery pack in the aging group, the remaining power is allocated to each battery pack in the aging group. The remaining power is the total target power minus the total allocated power, where the total allocated power is the sum of the power already allocated to all battery packs in the healthy group. Based on the battery temperature and rated power of each battery pack, the operating limit power value of each battery pack is determined, including: Based on the set over-temperature threshold, the rated power of each battery pack, and the actual operating temperature of each battery pack, the temperature power limit of each battery pack is determined. Based on the rated power limit and temperature power limit of each battery pack, the operating limit power value of each battery pack is determined; The determination of temperature power limits for each battery pack based on a set over-temperature threshold, the rated power of each battery pack, and the actual operating temperature of each battery pack includes: The temperature ratio of each battery pack is determined based on the ratio of the allowable temperature difference to the actual temperature difference of each battery pack. The actual temperature difference is the difference between the over-temperature threshold and the actual operating temperature. The allowable temperature difference is the allowable temperature gap from the over-temperature threshold. Based on the temperature ratio of the battery pack and the rated power of the battery pack, the power difference limit of the battery pack is determined; The temperature power limit of the battery pack is determined based on the rated power of the battery pack and the power difference limit of the battery pack.

2. The method according to claim 1, characterized in that, Based on the health status of each battery pack, the battery packs are divided into a healthy group and an aging group, including: If the maximum health difference in each battery pack is greater than or equal to the health difference threshold, the battery packs with a health difference greater than or equal to the health difference threshold are classified into the aging group, and the battery packs with a health difference less than the health difference threshold are classified into the healthy group. The maximum health difference is the difference between the maximum and minimum health of each battery pack, and the health difference of each battery pack is the difference between the maximum health of each battery pack and the health of each battery pack itself.

3. The method according to claim 1 or 2, characterized in that, Setting the target group as the healthy group or the aging group and setting the target execution power as the total target power or the remaining power; allocating the target execution power to each battery pack in the target group according to the operating limit power value and the state of charge of each battery pack in the target group, including: Based on the state of charge of all battery packs in the target group, determine whether the energy of each battery pack in the target group is balanced; If the energy is balanced, the target execution power is allocated to each target battery pack in the target group based on the operating limit power value of each battery pack in the target group and the state of charge. Otherwise, based on the state of charge of all battery packs in the target group, the target group is divided into an equalized group and an unbalanced group, and the target execution power is allocated to the equalized group and the unbalanced group respectively.

4. The method according to claim 3, characterized in that, If energy is balanced, the target execution power is allocated to each target battery pack in the target group based on the operating limit power value of each battery pack in the target group and the state of charge, including: If the energy is balanced, a first reference power for each battery pack in the target group is determined based on the ratio of the states of charge of each battery pack in the target group and the target execution power. When the first reference power is greater than or equal to the operating limit power value of the battery pack, the operating limit power value is allocated to the battery pack; When the first reference power is less than the operating limit power value of the battery pack, the first reference power is allocated to the battery pack.

5. The method according to claim 3, characterized in that, The allocation of the target execution power to the balanced group and the unbalanced group respectively includes: If the sum of the operating limit power values ​​of each battery pack in the equalization group is greater than or equal to the target execution power, the power allocation of each battery pack in the equalization group is determined according to the proportion of the state of charge of each battery pack in the equalization group and the target execution power. If the sum of the operating limit power values ​​of each battery pack in the balanced group is less than the target execution power, and the sum of the operating limit power values ​​of each battery pack in the balanced group and the unbalanced group is greater than or equal to the target execution power, the operating limit power values ​​are allocated to each battery pack in the balanced group. A first power to be allocated is determined based on the operating limit power values ​​of each battery pack in the balanced group and the target execution power. The first power to be allocated is allocated to each battery pack in the unbalanced group based on the size ratio of the state of charge of each battery pack in the unbalanced group and the first power to be allocated. If the sum of the operating limit power values ​​of each battery pack in the balanced group and the unbalanced group is less than the target execution power, the operating limit power value is allocated to each battery pack in each balanced group and the unbalanced group.

6. The method according to claim 4 or 5, characterized in that, The reference group is set as either a balanced group or an unbalanced group, and the power to be allocated is set as the target execution power or the first power to be allocated; the method further includes: Determine whether the sum of the allocated power corresponding to each battery pack in the reference group is less than the power to be allocated; If the sum of the allocated power of each battery pack in the reference group is less than the power to be allocated, the battery packs in the reference group are divided into a full-power operation group and a non-full-power operation group based on the allocated power of each battery pack in the reference group and the working limit power value, wherein the allocated power of each battery pack in the full-power operation group is equal to the working limit power value. Based on the allocated power of each battery pack in the full-power operation group and the power to be allocated, the second power to be allocated is determined; Based on the proportion of the state of charge of each battery pack in the non-full power operation group and the second power to be allocated, the second reference power of each battery pack in the non-full power operation group is determined; When the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is greater than or equal to the working limit power value of the battery pack, the new allocated power of the battery pack in the non-full power operation group is determined as the working limit power value, and the battery pack in the non-full power operation group is assigned to the full power operation group. When the sum of the second reference power and the allocated power of the battery pack in the non-full power operation group is less than the operating limit power value of the battery pack, the new allocated power of the battery pack in the non-full power operation group is determined to be the sum of the second reference power and the allocated power, and the step of determining whether the sum of the allocated power corresponding to each battery pack in the reference group is less than the power to be allocated is continued until the sum of the allocated power corresponding to each battery pack in the reference group is equal to the power to be allocated.

7. The method according to claim 3, characterized in that, Based on the state of charge of all battery packs in the target group, determine whether the energy of each battery pack in the target group is balanced, including: Obtain the maximum value of the state of charge of all battery packs within the target group; Obtain the minimum state of charge of all battery packs within the target group; Calculate the charge difference between the maximum and minimum values; If the charge difference is less than or equal to a preset threshold, then the battery packs in the target group are in energy balance. If the charge difference is greater than the preset threshold, then the battery packs in the target group are energy-uneven.

8. A battery pack energy balancing system, characterized in that, The system includes: Each battery pack; Each bidirectional DC module has its positive and negative terminals connected to a battery pack via a contactor, and its positive and negative terminals are connected to a busbar. A battery equalizer, wherein the first port of the battery equalizer is communicatively connected to each of the bidirectional DC modules, and the second port of the battery equalizer is communicatively connected to each of the battery packs; the battery equalizer is used to perform the battery pack energy equalization method according to any one of claims 1 to 7.

9. An energy storage device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

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