Battery Pack Voltage Balancing Control Method, Device, Energy Storage System and Storage Medium

Abstract

The present invention discloses a battery pack voltage balancing control method, device, energy storage system and storage medium. The battery pack voltage balancing control method includes: collecting voltage information during the charging and discharging process of the battery pack in real time, determining whether there is a voltage inconsistency among the battery cells in the battery pack, and recommending different battery pack maintenance methods according to the type of voltage inconsistency of the battery cells. If it is determined that the current battery pack needs balancing maintenance, the active balancing module in the battery pack is controlled to automatically perform balancing control according to the set balancing start condition and stop condition, so as to level the voltages of the inconsistent battery cells. The present invention realizes the automatic control of the battery pack voltage balance, does not require human intervention, has high reliability and high efficiency, and at the same time, reduces the labor and material costs.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular, to a method and device for controlling the voltage balance of a battery pack, an energy storage system, and a storage medium. Background Art

[0002] With the increase in the number of electric vehicles, the power batteries to be retired can be applied to energy storage systems, which can not only reduce resource waste and environmental pollution, but also generate certain economic value. In an energy storage system, in order to improve the storage capacity, multiple battery packs are connected in parallel. If the consistency difference between multiple battery packs is large, it is necessary to repeatedly turn on the balance control of the battery packs before the energy storage system is powered on to level the voltages of the multiple battery packs.

[0003] The current voltage balance control of the battery pack is completed through off-line charge and discharge tests of the battery pack. The test personnel need to manually export the charge and discharge test data and determine the maintenance plan of the battery pack by fitting the data curve. If it is determined that the state of charge of the batteries in the battery pack is inconsistent, it is necessary to perform separate charge and discharge processing on the batteries. The current conventional processing scheme for performing separate charge and discharge processing on the batteries is to disassemble the battery pack, find the battery cells that need to be balanced, damage a certain protective layer, and thus find the positive and negative electrode tab busbars of the corresponding batteries. The battery cells are charged and discharged by clamping the clips of the charge and discharge device on the positive and negative electrode tab busbars of the corresponding batteries. If there are multiple batteries in the battery pack that need to balance the voltage, the efficiency of this scheme will be extremely low. Summary of the Invention

[0004] The present invention provides a method and device for controlling the voltage balance of a battery pack, an energy storage system, and a storage medium, so as to solve the problems of low automation and low efficiency in the current voltage balance control of the battery pack, and at the same time, it is necessary to disassemble the battery pack and damage some protective devices, thereby causing cost waste.

[0005] According to one aspect of the present invention, there is provided a method for controlling the voltage balance of a battery pack, the method for controlling the voltage balance of the battery pack including:

[0006] Charging and discharging the current battery pack, and collecting the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack;

[0007] Determining a first charging end voltage of the current battery pack and its corresponding first serial number, a second charging end voltage and its corresponding second serial number, a first discharging end voltage and its corresponding third serial number, and a second discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell;

[0008] Determine whether the current battery pack needs equalization maintenance according to the first charging terminal voltage and its corresponding first serial number, the second charging terminal voltage and its corresponding second serial number, the first discharging terminal voltage and its corresponding third serial number, and the second discharging terminal voltage and its corresponding fourth serial number;

[0009] When it is determined that the current battery pack needs equalization maintenance, determine the average charging terminal voltage and the average discharging terminal voltage according to the current charging terminal voltage and the current discharging terminal voltage of each battery cell, and control the voltage equalization of each battery cell of the current battery pack according to the first charging terminal voltage, the second charging terminal voltage, the first discharging terminal voltage, the second discharging terminal voltage, the average charging terminal voltage, and the average discharging terminal voltage.

[0010] Optionally, after collecting the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack, it further includes:

[0011] Judge whether the current battery pack has reached the charge and discharge cut-off conditions for both charging and discharging;

[0012] Collecting the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack includes:

[0013] If the charge and discharge of the current battery pack have both reached the charge and discharge cut-off conditions, record the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack;

[0014] If the charge and discharge of the current battery pack do not reach the charge and discharge cut-off conditions, collect the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack again.

[0015] Optionally, the determining whether the current battery pack needs equalization maintenance according to the first charging terminal voltage and its corresponding first serial number, the second charging terminal voltage and its corresponding second serial number, the first discharging terminal voltage and its corresponding third serial number, and the second discharging terminal voltage and its corresponding fourth serial number includes:

[0016] When the first serial number corresponding to the first charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, the second serial number corresponding to the second charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the first serial number corresponding to the first charging terminal voltage is the same as the third serial number corresponding to the first discharging terminal voltage, it is determined that the current battery pack needs equalization maintenance; or,

[0017] When the first serial number corresponding to the first charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is the same as the fourth serial number corresponding to the second discharging terminal voltage, it is determined that the current battery pack needs equalization maintenance.

[0018] Optionally, the battery pack voltage equalization control method further includes:

[0019] When the first serial number corresponding to the first charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the first serial number corresponding to the first charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, it is determined whether the voltage difference between the first discharging terminal voltage and the second discharging terminal voltage is greater than a preset voltage difference threshold, or it is determined whether the discharging capacity of the current battery pack exceeds a standard discharging capacity threshold;

[0020] If it is determined that the voltage difference between the first discharging terminal voltage and the second discharging terminal voltage is greater than the preset voltage difference threshold, or it is determined that the discharging capacity of the current battery pack exceeds the standard discharging capacity threshold, it is determined that the current battery pack needs equalization maintenance.

[0021] Optionally, controlling the voltage equalization of each battery cell of the current battery pack according to the first charging terminal voltage, the second charging terminal voltage, the first discharging terminal voltage, the second discharging terminal voltage, the average charging terminal voltage, and the average discharging terminal voltage includes

[0022] If the voltage difference between the first charging terminal voltage and the average charging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the second charging terminal voltage and the average charging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the first discharging terminal voltage and the average discharging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the second discharging terminal voltage and the average discharging terminal voltage is greater than the equalization switch threshold, control the voltage equalization of each battery cell of the current battery pack.

[0023] Optionally, the battery pack voltage equalization control method further includes:

[0024] Obtain the number of battery cells to be voltage equalized;

[0025] If the number of voltage equalizations is 1, then again based on the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average charging end voltage, and the average discharging end voltage, determine whether to control the voltage equalization of each battery cell of the current battery pack;

[0026] If the number of voltage equalizations is greater than 1, then control the voltage equalization of each battery cell of the current battery pack according to the battery cells corresponding to the number of voltage equalizations.

[0027] Optionally, the controlling the voltage equalization of each battery cell of the current battery pack according to the battery cells corresponding to the number of voltage equalizations includes:

[0028] Determine the number of cells to be charged and the number of cells to be discharged according to the number of voltage equalizations, where the number of cells to be charged and the number of cells to be discharged may be the same or different;

[0029] When the number of cells to be charged and the number of cells to be discharged are the same, control the cells to be charged and the cells to be discharged to perform voltage equalization control for each battery cell of the current battery pack one by one;

[0030] When the number of cells to be charged and the number of cells to be discharged are different, perform screening according to the magnitude of the pressure difference to perform voltage equalization control for each battery cell of the current battery pack.

[0031] According to another aspect of the present invention, there is provided a battery pack voltage equalization control device, where the battery pack voltage equalization control device includes:

[0032] An end voltage determination module, configured to perform charging and discharging on the current battery pack and collect the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack;

[0033] A serial number information determination module, configured to perform determining the first charging end voltage of the current battery pack and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell;

[0034] An equalization maintenance determination module, configured to perform determining whether the current battery pack needs equalization maintenance according to the first charging end voltage and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number;

[0035] A voltage equalization control module, configured to, when it is determined that the current battery pack needs equalization maintenance, determine an average charging terminal voltage and an average discharging terminal voltage according to the current charging terminal voltage and the current discharging terminal voltage of each battery cell, and control the voltage equalization of each battery cell of the current battery pack according to the first charging terminal voltage, the second charging terminal voltage, the first discharging terminal voltage, the second discharging terminal voltage, the average charging terminal voltage, and the average discharging terminal voltage.

[0036] According to another aspect of the present invention, there is provided an energy storage system, the energy storage system comprising:

[0037] At least one processor; and

[0038] A memory communicatively connected to the at least one processor; wherein,

[0039] The memory stores a computer program executable by the at least one processor, and when the computer program is executed by the at least one processor, the at least one processor is enabled to execute the battery pack voltage equalization control method according to any embodiment of the present invention.

[0040] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for enabling a processor to implement the battery pack voltage equalization control method according to any embodiment of the present invention when executed.

[0041] The technical solution of the embodiment of the present invention charges and discharges the current battery pack, and collects the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack; determines the first charging end voltage of the current battery pack and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell; determines whether the current battery pack needs balance maintenance according to the first charging end voltage and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number; when it is determined that the current battery pack needs balance maintenance, determines the average value of the charging end voltage and the average value of the discharging end voltage according to the current charging end voltage and the current discharging end voltage of each battery cell, and controls the voltage balance of each battery cell of the current battery pack according to the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average value of the charging end voltage, and the average value of the discharging end voltage. The present invention solves the problems of low automation degree and low efficiency of the current battery pack voltage balance control, and at the same time, it is necessary to disassemble the battery pack and damage some protection devices, thereby causing cost waste, so as to realize the automatic control of the battery pack voltage balance, with high reliability and high efficiency. At the same time, the labor and material costs are reduced.

[0042] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Brief Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0044] Figure 1 is a flowchart of a method for controlling the voltage balance of a battery pack according to Embodiment 1 of the present invention;

[0045] Figure 2 is a flowchart of a method for determining the balance maintenance of a battery pack according to Embodiment 2 of the present invention;

[0046] Figure 3 is a flowchart of a method for executing the voltage balance control of a battery pack according to Embodiment 2 of the present invention;

[0047] Figure 4 is the topology architecture diagram of the applicable energy storage system provided according to the embodiments of the present invention;

[0048] Figure 5 is the structural schematic diagram of a battery pack voltage equalization control device provided according to Embodiment 3 of the present invention;

[0049] Figure 6 is the structural schematic diagram of the energy storage system for implementing the battery pack voltage equalization control method of the embodiments of the present invention. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] Embodiment 1

[0053] Figure 1 This is a flowchart of a battery pack voltage equalization control method provided for Embodiment 1 of the present invention. This embodiment is applicable to the situation of determining the consistency maintenance of the battery pack voltage and actively equalizing. The battery pack voltage equalization control method can be executed by a battery pack voltage equalization control device. The battery pack voltage equalization control device can be implemented in the form of hardware and / or software, and the battery pack voltage equalization control device can be configured in an energy storage system. As Figure 1 shown, the battery pack voltage equalization control method includes:

[0054] S110. Charge and discharge the current battery pack, and collect the current charging end voltage and the current discharging end voltage of each battery cell in the current battery pack.

[0055] Among them, the current battery pack can be the battery pack to be voltage equalized in the energy storage system, and the battery pack voltage equalization control method of this embodiment is applicable to any battery pack in the energy storage system.

[0056] In this embodiment, the current battery pack can be charged and discharged by connecting a charge and discharge device, that is, turn on the charge and discharge device to charge and discharge the current battery pack.

[0057] Specifically, after the charging and discharging of the current battery pack is completed, the battery management system BMS actively collects the current charging end voltage and the current discharging end voltage of each battery cell in the current battery pack in real time.

[0058] It can be understood that a battery pack (pack) is generally composed of a collection of multiple battery groups (Batteries), and a battery group (Batteries) is composed of a collection of multiple single-cell (cell) battery cells to provide higher voltage and capacity. In this embodiment, the multiple battery cells included in the battery pack are collected respectively to obtain the corresponding current charging end voltage and current discharging end voltage.

[0059] Furthermore, to ensure the accuracy of the battery pack consistency determination, after collecting the current charging end voltage and the current discharging end voltage of each battery cell in the current battery pack, it further includes: determining whether the current battery pack has reached the charge and discharge cut-off conditions for both charging and discharging.

[0060] Among them, the charge and discharge cut-off conditions can be that the charging end voltage and the discharging end voltage reach a certain threshold, or the temperature during the charge and discharge of the battery pack reaches a certain threshold. Optionally, the charge and discharge cut-off conditions can be that the charging end voltage reaches 3.6V, the discharging end voltage reaches 2.5V, or the charge and discharge cut-off conditions can be that the temperature during the charge and discharge of the battery pack is as high as 55°C, or the temperature during the charge and discharge of the battery pack is lower than 0°C.

[0061] On this basis, if the charge and discharge of the current battery pack both reach the charge and discharge cut-off conditions, record the current charging end voltage and the current discharging end voltage of each battery cell in the current battery pack; if the charge and discharge of the current battery pack do not reach the charge and discharge cut-off conditions, collect the current charging end voltage and the current discharging end voltage of each battery cell in the current battery pack again, and re-determine whether the current battery pack has reached the charge and discharge cut-off conditions for both charging and discharging.

[0062] S120. Determine the first charging end voltage of the current battery pack and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell.

[0063] Among them, in order to control the battery cells to perform voltage equalization and determine the battery cells in the battery pack in a timely manner, serial numbers are assigned to each battery cell. They can be numbered sequentially in order, or numbered in a certain specific letter or name, etc. This embodiment does not impose any restrictions on this.

[0064] Specifically, after obtaining the current charging end voltage and the current discharging end voltage of all battery cells in the battery pack, the highest charging end voltage among all battery cells is used as the first charging end voltage, and at the same time, the first serial number corresponding to the first charging end voltage is obtained; the lowest charging end voltage among all battery cells is used as the second charging end voltage, and at the same time, the second serial number corresponding to the second charging end voltage is obtained; the highest discharging end voltage among all battery cells is used as the first discharging end voltage, and at the same time, the third serial number corresponding to the first discharging end voltage is obtained; the lowest discharging end voltage among all battery cells is used as the second discharging end voltage, and at the same time, the fourth serial number corresponding to the second discharging end voltage is obtained.

[0065] It can be understood that the first serial number, the second serial number, the third serial number, and the fourth serial number are respectively the corresponding serial numbers of one of all battery cells. Then the first serial number, the second serial number, the third serial number, and the fourth serial number can be the same or different, which is specifically determined according to the actual charge and discharge conditions of the battery cells, that is, determined by the high and low values of the above-mentioned charge and discharge end voltages.

[0066] S130. Determine whether the current battery pack needs equalization maintenance according to the first charging end voltage and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number.

[0067] On the basis above, determine whether the first serial number corresponding to the first charging terminal voltage is the same as the fourth serial number corresponding to the second discharging terminal voltage. If so, it can be prompted that the battery pack needs to be unpacked and replaced manually, and the corresponding battery cells are maintained or the corresponding busbars are repaired. If not, determine whether the second serial number corresponding to the second charging terminal voltage is the same as the third serial number corresponding to the first discharging terminal voltage. If so, it can be prompted that the capacity of the battery pack is large and no maintenance is required. If not, determine whether the first serial number corresponding to the first charging terminal voltage is the same as the third serial number corresponding to the first discharging terminal voltage, or determine whether the second serial number corresponding to the second charging terminal voltage is the same as the fourth serial number corresponding to the second discharging terminal voltage. When any of the above two is the same, it is determined that the current battery pack needs to be balanced and maintained.

[0068] Further, if it is determined that the first serial number corresponding to the first charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, then determine whether the voltage difference between the first discharging terminal voltage and the second discharging terminal voltage is greater than a preset voltage difference threshold, or determine whether the discharging capacity of the current battery pack exceeds a standard discharging capacity threshold. When any of the above two exceeds the threshold, it is determined that the current battery pack needs to be balanced and maintained.

[0069] If the voltage difference between the first discharging terminal voltage and the second discharging terminal voltage is not greater than the preset voltage difference threshold, and the discharging capacity of the current battery pack does not exceed the standard discharging capacity threshold, it is prompted that the current battery pack is normal and no maintenance is required.

[0070] It should be noted that both step S120 and step S130 are realized by further determination after the battery management system BMS obtains the voltage information of all battery cells in the battery pack.

[0071] S140. When it is determined that the current battery pack needs to be balanced and maintained, determine the average charging terminal voltage and the average discharging terminal voltage according to the current charging terminal voltage and the current discharging terminal voltage of each battery cell, and control the voltage balance of each battery cell in the current battery pack according to the first charging terminal voltage, the second charging terminal voltage, the first discharging terminal voltage, the second discharging terminal voltage, the average charging terminal voltage and the average discharging terminal voltage.

[0072] It can be understood that when it is determined by the battery management system (BMS) that the current battery pack needs equalization maintenance, the BMS obtains a preset equalization switch threshold. The equalization switch threshold can be selected and set by those skilled in the art through the BMS according to the actual situation, and no specific limitation is imposed on the specific value of the equalization switch threshold in this embodiment.

[0073] Specifically, if the voltage difference between the first charging end voltage and the average value of the charging end voltages is greater than the equalization switch threshold, and the voltage difference between the second charging end voltage and the average value of the charging end voltages is greater than the equalization switch threshold, and the voltage difference between the first discharging end voltage and the average value of the discharging end voltages is greater than the equalization switch threshold, and the voltage difference between the second discharging end voltage and the average value of the discharging end voltages is greater than the equalization switch threshold, control the voltage equalization of each battery cell of the current battery pack. If any of the above conditions is not satisfied, stop controlling the voltage equalization operation of the current battery pack, indicating that the voltage equalization control is ended.

[0074] Further, on the basis of the above embodiment, after determining to control the voltage equalization of each battery cell of the current battery pack, obtain the number of battery cells to be voltage-equalized; if the number of battery cells to be voltage-equalized is 1, then again determine whether to control the voltage equalization of each battery cell of the current battery pack according to the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average value of the charging end voltages, and the average value of the discharging end voltages; if the number of battery cells to be voltage-equalized is greater than 1, then control the voltage equalization of each battery cell of the current battery pack according to the battery cells corresponding to the number of battery cells to be voltage-equalized.

[0075] On the above basis, determine the number of battery cells to be charged and the number of battery cells to be discharged according to the number of battery cells to be voltage-equalized, and the number of battery cells to be charged and the number of battery cells to be discharged may be the same or different; when the number of battery cells to be charged and the number of battery cells to be discharged are the same, control the battery cells to be charged and the battery cells to be discharged to perform the voltage equalization control of each battery cell of the current battery pack one by one; when the number of battery cells to be charged and the number of battery cells to be discharged are different, perform the voltage equalization control of each battery cell of the current battery pack by screening according to the magnitude of the pressure difference.

[0076] In the technical solution of the embodiment of the present invention, by charging and discharging the current battery pack, the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack are collected; according to the current charging end voltage and the current discharging end voltage of each battery cell, the first charging end voltage of the current battery pack and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number are determined; according to the first charging end voltage and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number, it is determined whether the current battery pack needs equalization maintenance; when it is determined that the current battery pack needs equalization maintenance, the average charging end voltage and the average discharging end voltage are determined according to the current charging end voltage and the current discharging end voltage of each battery cell, and according to the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average charging end voltage, and the average discharging end voltage, the voltage of each battery cell of the current battery pack is controlled to be balanced. The present invention solves the problems of low automation degree and low efficiency in the current battery pack voltage equalization control, and at the same time, it is necessary to disassemble the battery pack and damage some protection devices, thereby causing cost waste, so as to realize the automatic control of the battery pack voltage equalization, with high reliability and high efficiency. At the same time, the labor and material costs are reduced.

[0077] Embodiment 2

[0078] Figure 2 It is a flowchart of the method for determining the equalization maintenance of the battery pack provided by the second embodiment of the present invention. Figure 3 It is a flowchart of the method for performing the battery pack voltage equalization control provided by the second embodiment of the present invention. On the basis of the above embodiment, the process of the battery pack voltage equalization control method is further refined. At the same time, a topology architecture diagram of the energy storage system as shown in Figure 4 is provided to detail the information interaction schematic process between the battery pack, the energy storage system, and the remote monitoring platform. As shown in Figure 1 , Figure 2 and Figure 4 shown, the method for determining the equalization maintenance of the battery pack includes:

[0079] S110. Charge and discharge the current battery pack, and collect the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack.

[0080] Continue to refer to Figure 4, the battery pack is the current battery pack described in this embodiment. The battery pack contains several battery groups (B1-, B1+... B11+, B12+,..., B61-, B61+... B71+, B72+) formed by series and parallel connection through busbars. Temperature sensors (T1... T3,..., T16... T18) are arranged on the battery groups, and information is collected into the active equalization module (BMU-1... BMU-6) through voltage and temperature sampling lines. The active equalization module (BMU-1... BMU-6) contains several bidirectional DCDC modules. The voltage input terminal (DC2-5V) of the DCDC module is connected to each battery cell it manages through a switch matrix, and the output terminal (DC24V) is connected to the power supply of the active equalization module (BMU-1... BMU-6). Each battery pack is composed of several active equalization modules (BMU-1... BMU-6).

[0081] Exemplarily, if the voltage of a single battery cell managed by the active equalization module BMU-1 is too high and the voltage of a single battery cell managed by the active equalization module BMU-6 is too low, the active equalization module BMU-1 and the active equalization module BMU-6 respectively select the corresponding battery cells with too high and too low voltages and connect them to the DCDC through the switch matrix. The active equalization module BMU-1 controls bidirectional discharging, and the active equalization module BMU-6 controls bidirectional charging. That is, it is equivalent to transferring the electricity from the high-voltage battery cell in the active equalization module BMU-1 to the low-voltage battery cell in the active equalization module BMU-6 through two bidirectional DCDCs. Conversely, if the voltage of the battery cell managed by the active equalization module BMU-6 is high and the voltage of the battery cell managed by the active equalization module BMU-1 is low, the electricity can also be transferred from the high-voltage battery cell in the active equalization module BMU-6 to the low-voltage battery cell in the active equalization module BMU-1 through two bidirectional DCDCs.

[0082] It should be noted that, continue to refer to Figure 4 , the energy storage system further includes a switching power supply. The switching power supply is plugged into a 220V plug through a plug, and the other end outputs 24V voltage to supply power to the active equalization module (BMU-1... BMU-6) and the battery management system BMS in the battery pack.

[0083] S210. Determine whether the current battery pack has reached the charge and discharge cut-off conditions for both charging and discharging. If so, execute step S120; if not, execute step S110.

[0084] S120. Determine the first charging end voltage and its corresponding first serial number, the second charging end voltage and its corresponding second serial number, the first discharging end voltage and its corresponding third serial number, and the second discharging end voltage and its corresponding fourth serial number of the current battery pack according to the current charging end voltage and the current discharging end voltage of each battery cell.

[0085] S230. Determine whether the first serial number corresponding to the first charging end voltage is the same as the fourth serial number corresponding to the second discharging end voltage. If so, execute step S231; if not, execute step S240.

[0086] S231. It can be prompted that the battery pack needs to be unpacked and replaced manually, and the corresponding battery cells are maintained or the corresponding busbars are repaired.

[0087] Combined with Figure 2 and Figure 4 it can be known that the upper computer of the PC computer can be used to prompt that the battery pack needs to be unpacked and replaced manually, and the corresponding battery cells are maintained or the corresponding busbars are repaired.

[0088] S240. Determine whether the second serial number corresponding to the second charging end voltage is the same as the third serial number corresponding to the first discharging end voltage. If so, execute step S241; if not, execute step S250.

[0089] S241. It can be prompted that the battery pack has a large capacity and does not need to be maintained.

[0090] Combined with Figure 2 and Figure 4 it can be known that the upper computer of the PC computer can be used to prompt that the battery pack has a large capacity and does not need to be maintained.

[0091] S250. Determine whether the first serial number corresponding to the first charging end voltage is the same as the third serial number corresponding to the first discharging end voltage, or determine whether the second serial number corresponding to the second charging end voltage is the same as the fourth serial number corresponding to the second discharging end voltage. If any of the above two is the same, execute step S251; if not, execute step S260.

[0092] S251. Determine that the current battery pack needs to be balanced and maintained.

[0093] Combined with Figure 2 and Figure 4 it can be known that the upper computer of the PC computer can be used to determine that the current battery pack needs to be balanced and maintained, and automatically execute the voltage balance control of the battery pack.

[0094] S260. Determine whether the voltage difference between the first discharging end voltage and the second discharging end voltage is greater than the preset voltage difference threshold, or determine whether the discharging capacity of the current battery pack exceeds the standard discharging capacity threshold. If any of the above two exceeds the threshold, execute step S261; if not, execute step S270.

[0095] S261. Determine that the current battery pack needs to be balanced and maintained.

[0096] Combined with Figure 2 and Figure 4 it can be known that the upper computer of the PC can determine that the current battery pack needs balanced maintenance and automatically execute the battery pack voltage balance control.

[0097] S270. Prompt that the current battery pack is normal and no maintenance is required.

[0098] In addition, it should be noted that continue to refer to Figure 4 , the battery management system BMS exchanges information with the active balance modules (BMU-1...BMU-6) in the battery pack through the CAN communication line to obtain all battery voltage and temperature information; on the other hand, it is electrically connected to the PC through CAN to USB, and then various information obtained in this embodiment (including single-cell battery voltage, temperature, maximum and minimum charge and discharge voltages, maximum and minimum charge and discharge temperatures, etc.) is displayed on the monitoring upper computer of the PC.

[0099] It can be known that the battery management system BMS can identify the state of the battery pack during the charge and discharge process and display the result of the method for determining the battery pack balance maintenance on the monitoring upper computer of the PC. The specific working process of the method for determining the battery pack balance maintenance is as described in the above steps S110 to S270. In addition, when it is determined that the current battery pack needs balanced maintenance, the battery management system BMS controls the automatic balance operation according to the balance switch threshold set by the PC. The specific working process is as follows in the process of executing the battery pack voltage balance control method.

[0100] Based on the above embodiment, if it is determined that the current battery pack needs balanced maintenance, step S140 will be specifically explained. As Figure 3 shown, the method for executing the battery pack voltage balance control specifically includes:

[0101] S310. Obtain the preset balance switch threshold through the battery management system BMS.

[0102] S320. Judge whether the voltage differences between the first charging end voltage, the second charging end voltage, the first discharging end voltage, and the second discharging end voltage and the average charging end voltage and the average discharging end voltage are greater than the balance switch threshold. If so, execute step S340; if not, execute step S330.

[0103] Specifically, if the voltage difference between the first charging terminal voltage and the average charging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the second charging terminal voltage and the average charging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the first discharging terminal voltage and the average discharging terminal voltage is greater than the equalization switch threshold, and the voltage difference between the second discharging terminal voltage and the average discharging terminal voltage is greater than the equalization switch threshold, control the voltage equalization of each battery cell in the current battery pack. If any of the above conditions is not met, stop controlling the voltage equalization operation of the current battery pack, indicating the end of the voltage equalization control.

[0104] S330. Stop controlling the voltage equalization operation of the current battery pack.

[0105] S340. Obtain the voltage equalization quantity of the battery cells to be voltage equalized, and execute step S350.

[0106] S350. Determine whether the voltage equalization quantity is 1. If it is, execute step S320. If not, execute step S360.

[0107] It can be understood that when the voltage equalization quantity is 1, wait until step S320 is executed next time and then re-judge. Usually, the judgment is restarted within a certain period of time. The specific time interval can be selected and set by those skilled in the art. Optionally, execute step S320 again every minute.

[0108] S360. Control the voltage equalization of each battery cell in the current battery pack according to the battery cells corresponding to the voltage equalization quantity, and execute step S320 again to re-judge the equalization switch threshold.

[0109] On the above basis, determine the number of battery cells to be charged and the number of battery cells to be discharged according to the voltage equalization quantity. The number of battery cells to be charged and the number of battery cells to be discharged may be the same or different; when the number of battery cells to be charged and the number of battery cells to be discharged are the same, control the battery cells to be charged and the battery cells to be discharged to perform the voltage equalization control of each battery cell in the current battery pack one by one; when the number of battery cells to be charged and the number of battery cells to be discharged are different, perform the voltage equalization control of each battery cell in the current battery pack according to the magnitude of the pressure difference for screening.

[0110] In this embodiment, the battery cells inside an active equalization module determine which one starts first based on the voltage magnitude. Different active equalization modules can be turned on simultaneously. However, some active equalization modules need to charge while some need to discharge. At this time, it can be understood that not all the battery cells in the active equalization module can charge or discharge. Exemplarily, it is detected that the number of voltage equalization is determined to be 6, among which, 4 cells to be charged and 2 cells to be discharged. Then, only the 2 cells to be discharged can be turned on first. For the 4 cells to be charged, 3 cells to be charged can be turned on first. Among these 3 cells to be charged, the one with the smallest voltage difference is selected not to be turned on first, and then the voltage equalization control of each battery cell of the current battery pack is correspondingly performed.

[0111] The technical solution of the embodiment of the present invention builds the energy storage system according to the Figure 4 topological architecture diagram, turns on the switching power supply and the PC computer, and connects the charging and discharging equipment to charge and discharge the current battery pack. After the charging and discharging of the current battery pack is completed, the battery management system BMS determines whether the current battery pack needs equalization maintenance according to the Figure 2 determined battery pack equalization maintenance method and displays it on the upper computer of the PC computer. If the current battery pack needs manual maintenance, those skilled in the art will perform unpacking processing; if the current battery pack needs automatic equalization maintenance, the energy storage system performs battery pack voltage equalization control according to the Figure 3 shown; if the current battery pack does not need maintenance, the offline can be completed. This energy storage system has a high degree of automation, avoids misjudgment caused by manual intervention, has high reliability, and can also reduce labor costs. The automatic battery pack voltage equalization control can avoid unpacking and avoid damaging some components, saving material and labor costs. In addition, when the battery pack voltage is automatically equalized, the number of balanced battery cells is large, and the efficiency is higher than that of manual charging and discharging.

[0112] Embodiment III

[0113] Figure 5 It is a schematic structural diagram of a battery pack voltage equalization control device provided by Embodiment III of the present invention. As Figure 5 shown, the battery pack voltage equalization control device includes:

[0114] The terminal voltage determination module 510 is configured to perform charging and discharging on the current battery pack and collect the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack;

[0115] The serial number information determination module 520 is configured to determine the first charging terminal voltage and its corresponding first serial number, the second charging terminal voltage and its corresponding second serial number, the first discharging terminal voltage and its corresponding third serial number, and the second discharging terminal voltage and its corresponding fourth serial number of the current battery pack according to the current charging terminal voltage and the current discharging terminal voltage of each battery cell;

[0116] An equalization maintenance judgment module 530, configured to determine whether the current battery pack needs equalization maintenance according to the first charging terminal voltage and its corresponding first serial number, the second charging terminal voltage and its corresponding second serial number, the first discharging terminal voltage and its corresponding third serial number, and the second discharging terminal voltage and its corresponding fourth serial number;

[0117] A voltage equalization control module 540, configured to, when it is determined that the current battery pack needs equalization maintenance, determine an average charging terminal voltage and an average discharging terminal voltage according to the current charging terminal voltage and the current discharging terminal voltage of each battery cell, and control the voltage equalization of each battery cell of the current battery pack according to the first charging terminal voltage, the second charging terminal voltage, the first discharging terminal voltage, the second discharging terminal voltage, the average charging terminal voltage, and the average discharging terminal voltage.

[0118] Optionally, the battery pack voltage equalization control device further includes:

[0119] A charge and discharge cut-off condition judgment module, configured to judge whether the current battery pack has reached the charge and discharge cut-off conditions for both charging and discharging;

[0120] Collecting the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack includes:

[0121] If the charge and discharge of the current battery pack have both reached the charge and discharge cut-off conditions, record the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack;

[0122] If the charge and discharge of the current battery pack do not reach the charge and discharge cut-off conditions, collect the current charging terminal voltage and the current discharging terminal voltage of each battery cell of the current battery pack again.

[0123] Optionally, the equalization maintenance judgment module 530 is specifically configured to:

[0124] When the first serial number corresponding to the first charging terminal voltage is different from the fourth serial number corresponding to the second discharging terminal voltage, and the second serial number corresponding to the second charging terminal voltage is different from the third serial number corresponding to the first discharging terminal voltage, and the first serial number corresponding to the first charging terminal voltage is the same as the third serial number corresponding to the first discharging terminal voltage, determine that the current battery pack needs equalization maintenance; or,

[0125] When the first serial number corresponding to the first charging end voltage is different from the fourth serial number corresponding to the second discharging end voltage, and the second serial number corresponding to the second charging end voltage is different from the third serial number corresponding to the first discharging end voltage, and the second serial number corresponding to the second charging end voltage is the same as the fourth serial number corresponding to the second discharging end voltage, it is determined that the current battery pack needs equalization maintenance.

[0126] Optionally, the battery pack voltage equalization control device further includes:

[0127] When the first serial number corresponding to the first charging end voltage is different from the fourth serial number corresponding to the second discharging end voltage, and the second serial number corresponding to the second charging end voltage is different from the third serial number corresponding to the first discharging end voltage, and the first serial number corresponding to the first charging end voltage is different from the third serial number corresponding to the first discharging end voltage, and the second serial number corresponding to the second charging end voltage is different from the fourth serial number corresponding to the second discharging end voltage, it is determined whether the voltage difference between the first discharging end voltage and the second discharging end voltage is greater than a preset voltage difference threshold, or it is determined whether the discharging capacity of the current battery pack exceeds a standard discharging capacity threshold;

[0128] If it is determined that the voltage difference between the first discharging end voltage and the second discharging end voltage is greater than the preset voltage difference threshold, or it is determined that the discharging capacity of the current battery pack exceeds the standard discharging capacity threshold, it is determined that the current battery pack needs equalization maintenance.

[0129] Optionally, controlling the voltage equalization of each battery cell of the current battery pack according to the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average charging end voltage, and the average discharging end voltage includes

[0130] If the voltage difference between the first charging end voltage and the average charging end voltage is greater than the equalization switch threshold, and the voltage difference between the second charging end voltage and the average charging end voltage is greater than the equalization switch threshold, and the voltage difference between the first discharging end voltage and the average discharging end voltage is greater than the equalization switch threshold, and the voltage difference between the second discharging end voltage and the average discharging end voltage is greater than the equalization switch threshold, control the voltage equalization of each battery cell of the current battery pack.

[0131] Optionally, the battery pack voltage equalization control device further includes:

[0132] A voltage equalization quantity acquisition module, configured to execute acquiring the voltage equalization quantity of the battery cells to be voltage equalized;

[0133] A voltage equalization judgment module, configured to execute: if the number of voltage equalizations is 1, then determine again whether to control the voltage equalization of each battery cell of the current battery pack according to the first charging end voltage, the second charging end voltage, the first discharging end voltage, the second discharging end voltage, the average charging end voltage, and the average discharging end voltage;

[0134] If the number of voltage equalizations is greater than 1, then control the voltage equalization of each battery cell of the current battery pack according to the battery cells corresponding to the number of voltage equalizations.

[0135] Optionally, the controlling the voltage equalization of each battery cell of the current battery pack according to the battery cells corresponding to the number of voltage equalizations includes:

[0136] Determine the number of battery cells to be charged and the number of battery cells to be discharged according to the number of voltage equalizations, where the number of battery cells to be charged and the number of battery cells to be discharged may be the same or different;

[0137] When the number of battery cells to be charged and the number of battery cells to be discharged are the same, control the battery cells to be charged and the battery cells to be discharged to perform voltage equalization control of each battery cell of the current battery pack in a one-to-one correspondence;

[0138] When the number of battery cells to be charged and the number of battery cells to be discharged are different, perform voltage equalization control of each battery cell of the current battery pack by screening according to the magnitude of the pressure difference.

[0139] The battery pack voltage equalization control device provided by the embodiments of the present invention can execute the battery pack voltage equalization control method provided by any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the battery pack voltage equalization control method.

[0140] Embodiment 4

[0141] Figure 6 FIG. shows a schematic structural diagram of an energy storage system 610 that can be used to implement the embodiments of the present invention. As Figure 6As shown, the energy storage system 610 includes at least one processor 611 and a memory communicatively connected to the at least one processor 611, such as read-only memory (ROM) 612, random access memory (RAM) 613, etc. The memory stores computer programs executable by the at least one processor. The processor 611 can perform various appropriate actions and processes according to the computer programs stored in the read-only memory (ROM) 612 or the computer programs loaded from the storage unit 618 into the random access memory (RAM) 613. In the RAM 613, various programs and data required for the operation of the energy storage system 610 can also be stored. The processor 611, ROM 612, and RAM 613 are connected to each other via a bus 614. The input / output (I / O) interface 615 is also connected to the bus 614.

[0142] Multiple components in the energy storage system 610 are connected to the I / O interface 615, including: an input unit 616, such as a keyboard, a mouse, etc.; an output unit 617, such as various types of displays, speakers, etc.; a storage unit 618, such as a magnetic disk, an optical disk, etc.; and a communication unit 619, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 619 allows the energy storage system 610 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0143] The processor 611 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 611 include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 611 executes the various methods and processes described above, such as the battery pack voltage equalization control method.

[0144] In some embodiments, the battery pack voltage equalization control method can be implemented as a computer program tangibly embodied in a computer-readable storage medium, such as the storage unit 618. In some embodiments, part or all of the computer program can be loaded and / or installed onto the energy storage system 610 via the ROM 612 and / or the communication unit 619. When the computer program is loaded into the RAM 613 and executed by the processor 611, one or more steps of the battery pack voltage equalization control method described above can be executed. Alternatively, in other embodiments, the processor 611 can be configured to execute the battery pack voltage equalization control method by any other appropriate means (e.g., by means of firmware).

[0145] The various embodiments of the systems and techniques described above in this specification can be implemented in digital electronic circuitry, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems-on-chip (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which may be a special-purpose or general-purpose programmable processor that receives data and instructions from, and transmits data and instructions to, a storage system, at least one input device, and at least one output device.

[0146] The computer program for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the computer programs, when executed by the processor, cause the functions / operations specified in the flowchart and / or block diagram to be implemented. The computer program may be executed entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine or entirely on the remote machine or server.

[0147] In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain, or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium may be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0148] To provide interaction with a user, the systems and techniques described herein can be implemented on an energy storage system having: a display device for displaying information to the user (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor); and a keyboard and a pointing device (e.g., a mouse or a trackball) through which the user can provide input to the energy storage system. Other kinds of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0149] The systems and techniques described herein can be implemented in a computing system including backend components (e.g., as a data server), or a computing system including middleware components (e.g., an application server), or a computing system including frontend components (e.g., a user computer having a graphical user interface or a web browser through which the user can interact with an implementation of the systems and techniques described herein), or a computing system including any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected to each other by digital data communication in any form or medium (e.g., a communication network). Examples of communication networks include: local area network (LAN), wide area network (WAN), blockchain network, and the Internet.

[0150] The computing system can include a client and a server. The client and the server are generally far from each other and usually interact through a communication network. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0151] It should be understood that various forms of the processes shown above can be used, with steps reordered, added, or deleted. For example, the steps recited in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0152] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for controlling the voltage balance of a battery pack, characterized in that, Including: Charging and discharging the current battery pack, and collecting the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack; Determining the first highest charging end voltage of the current battery pack and its corresponding first serial number, the second lowest charging end voltage and its corresponding second serial number, the first highest discharging end voltage and its corresponding third serial number, and the second lowest discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell; When the first serial number corresponding to the first highest charging end voltage is different from the fourth serial number corresponding to the second lowest discharging end voltage, and the second serial number corresponding to the second lowest charging end voltage is different from the third serial number corresponding to the first highest discharging end voltage, and the first serial number corresponding to the first highest charging end voltage is the same as the third serial number corresponding to the first highest discharging end voltage, it is determined that the current battery pack needs equalization maintenance; or, when the first serial number corresponding to the first highest charging end voltage is different from the fourth serial number corresponding to the second lowest discharging end voltage, and the second serial number corresponding to the second lowest charging end voltage is different from the third serial number corresponding to the first highest discharging end voltage, and the second serial number corresponding to the second lowest charging end voltage is the same as the fourth serial number corresponding to the second lowest discharging end voltage, it is determined that the current battery pack needs equalization maintenance; When it is determined that the current battery pack needs equalization maintenance, determining the average charging end voltage and the average discharging end voltage according to the current charging end voltage and the current discharging end voltage of each battery cell, and controlling the voltage equalization of each battery cell of the current battery pack according to the first highest charging end voltage, the second lowest charging end voltage, the first highest discharging end voltage, the second lowest discharging end voltage, the average charging end voltage, and the average discharging end voltage.

2. The battery pack voltage equalization control method according to claim 1, wherein After collecting the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack, it further includes: Judging whether the current battery pack has reached the charging and discharging cut-off conditions for both charging and discharging; Collecting the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack includes: If the charging and discharging of the current battery pack have both reached the charging and discharging cut-off conditions, recording the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack; If the charging and discharging of the current battery pack do not reach the charging and discharging cut-off conditions, collecting the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack again.

3. The battery pack voltage equalization control method according to claim 1, wherein The battery pack voltage equalization control method further includes: When the first serial number corresponding to the highest voltage of the first charging end is different from the fourth serial number corresponding to the lowest voltage of the second discharging end, and the second serial number corresponding to the lowest voltage of the second charging end is different from the third serial number corresponding to the highest voltage of the first discharging end, and the first serial number corresponding to the highest voltage of the first charging end is different from the third serial number corresponding to the highest voltage of the first discharging end, and the second serial number corresponding to the lowest voltage of the second charging end is different from the fourth serial number corresponding to the lowest voltage of the second discharging end, then determine whether the voltage difference between the highest voltage of the first discharging end and the lowest voltage of the second discharging end is greater than a preset voltage difference threshold, or determine whether the discharge capacity of the current battery pack exceeds a standard discharge capacity threshold; If it is determined that the voltage difference between the highest voltage of the first discharging end and the lowest voltage of the second discharging end is greater than the preset voltage difference threshold, or it is determined that the discharge capacity of the current battery pack exceeds the standard discharge capacity threshold, then it is determined that the current battery pack needs balancing maintenance.

4. The battery pack voltage equalization control method according to claim 1, characterized in that, The method for controlling the voltage balance of each battery cell of the current battery pack according to the highest voltage of the first charging end, the lowest voltage of the second charging end, the highest voltage of the first discharging end, the lowest voltage of the second discharging end, the average voltage of the charging end and the average voltage of the discharging end includes: If the voltage difference between the highest voltage of the first charging end and the average voltage of the charging end is greater than the balance switch threshold, and the voltage difference between the lowest voltage of the second charging end and the average voltage of the charging end is greater than the balance switch threshold, and the voltage difference between the highest voltage of the first discharging end and the average voltage of the discharging end is greater than the balance switch threshold, and the voltage difference between the lowest voltage of the second discharging end and the average voltage of the discharging end is greater than the balance switch threshold, control the voltage balance of each battery cell of the current battery pack.

5. The battery pack voltage equalization control method according to claim 4, wherein, The method for controlling the voltage balance of the battery pack further includes: Obtain the number of battery cells to be voltage balanced; If the number of battery cells to be voltage balanced is 1, then determine again whether to control the voltage balance of each battery cell of the current battery pack according to the highest voltage of the first charging end, the lowest voltage of the second charging end, the highest voltage of the first discharging end, the lowest voltage of the second discharging end, the average voltage of the charging end and the average voltage of the discharging end; If the number of battery cells to be voltage balanced is greater than 1, then control the voltage balance of each battery cell of the current battery pack according to the battery cells corresponding to the number of battery cells to be voltage balanced.

6. The battery pack voltage equalization control method according to claim 5, wherein, The method for controlling the voltage balance of each battery cell of the current battery pack according to the battery cells corresponding to the number of battery cells to be voltage balanced includes: Determine the number of battery cells to be charged and the number of battery cells to be discharged according to the number of battery cells to be voltage balanced, and the number of battery cells to be charged and the number of battery cells to be discharged may be the same or different; When the number of battery cells to be charged and the number of battery cells to be discharged are the same, control the battery cells to be charged and the battery cells to be discharged to correspond one by one to perform the voltage balance control of each battery cell of the current battery pack; When the number of battery cells to be charged and the number of battery cells to be discharged are different, voltage equalization control is performed for each battery cell of the current battery pack according to the magnitude of the voltage difference.

7. A battery pack voltage equalization control device, characterized in that It includes: An end voltage determination module, configured to perform charge and discharge on the current battery pack and collect the current charging end voltage and the current discharging end voltage of each battery cell of the current battery pack; A serial number information determination module, configured to determine the highest first charging end voltage of the current battery pack and its corresponding first serial number, the lowest second charging end voltage and its corresponding second serial number, the highest first discharging end voltage and its corresponding third serial number, and the lowest second discharging end voltage and its corresponding fourth serial number according to the current charging end voltage and the current discharging end voltage of each battery cell; wherein, the highest first charging end voltage is the highest charging end voltage among the battery cells, the lowest second charging end voltage is the lowest charging end voltage among the battery cells, the highest first discharging end voltage is the highest discharging end voltage among the battery cells, and the lowest second discharging end voltage is the lowest discharging end voltage among the battery cells; An equalization maintenance judgment module, configured to determine that the current battery pack needs equalization maintenance when the first serial number corresponding to the highest first charging end voltage is different from the fourth serial number corresponding to the lowest second discharging end voltage, and the second serial number corresponding to the lowest second charging end voltage is different from the third serial number corresponding to the highest first discharging end voltage, and the first serial number corresponding to the highest first charging end voltage is the same as the third serial number corresponding to the highest first discharging end voltage; or, when the first serial number corresponding to the highest first charging end voltage is different from the fourth serial number corresponding to the lowest second discharging end voltage, and the second serial number corresponding to the lowest second charging end voltage is different from the third serial number corresponding to the highest first discharging end voltage, and the second serial number corresponding to the lowest second charging end voltage is the same as the fourth serial number corresponding to the lowest second discharging end voltage, then determine that the current battery pack needs equalization maintenance; A voltage equalization control module, configured to determine the average charging end voltage and the average discharging end voltage according to the current charging end voltage and the current discharging end voltage of each battery cell when it is determined that the current battery pack needs equalization maintenance, and control the voltage equalization of each battery cell of the current battery pack according to the highest first charging end voltage, the lowest second charging end voltage, the highest first discharging end voltage, the lowest second discharging end voltage, the average charging end voltage, and the average discharging end voltage.

8. An energy storage system, characterized in that, The energy storage system includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the battery pack voltage equalization control method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for implementing the battery pack voltage equalization control method according to any one of claims 1-6 when executed by a processor.

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