Balancing method, device and equipment of multi-branch battery system and storage medium

Abstract

The invention discloses an equalization method, device and equipment of a multi-branch battery system and a storage medium, and relates to the technical field of power battery intelligent control, the method comprises the following steps: acquiring SOC range between battery branches in a power battery charging configuration stage, and judging: if the range is not less than a set percentage, adopting a one-by-one confluence charging mode for the battery branches, and if the range is not less than the set percentage, adopting a one-by-one confluence charging mode for the battery branches; quickly charging after all the battery branches are converged, and calculating the electric quantity required to be balanced in the battery cells in the fully-charged battery branches based on a preset algorithm, so as to realize electric quantity balance; if the range is smaller than the set percentage, all the battery branches are controlled to perform fast charging at the same time, and the electric quantity needing to be balanced in the battery cells in the fully-charged battery branches is calculated based on a preset algorithm, so that electric quantity balancing is achieved. According to the invention, the problem of unbalanced electric quantity existing among the branches of the multi-branch parallel battery pack can be effectively solved.

Description

Technical Field

[0001] The present application relates to the technical field of intelligent control of power batteries, and in particular to a method, device, equipment and storage medium for balancing a multi-branch battery system. Background Art

[0002] As the new energy vehicle market continues to expand, cell balancing, as an indispensable part of battery management, has received more and more attention. Due to differences in manufacturing processes, the initial state of each battery cell may be slightly different, which leads to inconsistent performance during the charge and discharge process. During use, the capacity of battery cells may differ due to factors such as the number of cycles, temperature changes, and increased internal resistance. This difference can cause some battery cells to be overcharged or over-discharged, thus affecting the overall performance and life of the battery. Cell balancing can ensure that each battery cell in the battery pack operates in a nearly identical state, extending the overall life of the battery pack, maximizing the performance of the battery pack, and improving energy utilization.

[0003] Since electric commercial vehicles have higher requirements for the endurance and output power of power batteries, the power battery system of commercial vehicles is mostly a multi-branch battery pack parallel solution. In addition to the cell balancing on a single branch, the parallel solution of multi-branch battery packs also requires the balance of power between branches. Most of the existing battery balancing strategies determine the start and end of battery balancing based on the battery cell voltage. Therefore, how to achieve the balance between battery branches has become a problem that needs to be solved urgently. Summary of the invention

[0004] The present application provides a method, device / system, equipment and computer-readable storage medium for balancing a multi-branch battery system, which can effectively solve the problem of power imbalance between branches of a multi-branch parallel battery pack.

[0005] In a first aspect, an embodiment of the present application provides a balancing method for a multi-branch battery system, the balancing method for a multi-branch battery system comprising:

[0006] In the power battery charging configuration stage, the SOC range between the battery branches is obtained and judged:

[0007] If the extreme difference is not less than the set percentage, the battery branches are charged one by one, and fast charging is performed after all battery branches are connected. The power required to be balanced in the fully charged battery branches is calculated based on the preset algorithm to achieve power balancing;

[0008] If the extreme difference is less than the set percentage, all battery branches are controlled to perform fast charging at the same time, and the power required to be balanced in the cells in the fully charged battery branch is calculated based on the preset algorithm to achieve power balance.

[0009] In combination with the first aspect, in one implementation, obtaining the SOC range difference between battery branches in the power battery charging configuration stage specifically includes:

[0010] Obtain the SOC of each battery branch during the power battery charging configuration stage;

[0011] Based on the acquired SOC of the battery branch, the SOC range between the battery branches is calculated.

[0012] In combination with the first aspect, in one implementation, the battery branches are charged one by one by merging currents, and fast charging is performed after all the battery branches are merged, specifically including:

[0013] Obtaining the battery branch with the lowest SOC and the battery branch with the second lowest SOC, closing the negative relay of the battery branch with the lowest SOC, and charging the battery branch based on the standard fast charging method;

[0014] The SOC of the battery branch with the lowest SOC is obtained in real time, and after summing it with the preset percentage SOC, it is determined whether the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC:

[0015] If yes, a smaller charging current of a set value is requested to charge the battery branches one by one, and after all the battery branches are charged, all the battery branches are fast charged based on the standard fast charging method;

[0016] If not, continue to charge the battery branch with the lowest SOC, then obtain the SOC of the battery branch with the lowest SOC again, and sum it with the preset percentage SOC until the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC, then request a smaller charging current of the set value, converge and charge the battery branches one by one, and after all battery branches are converged, fast charge all battery branches based on the standard fast charging method.

[0017] In combination with the first aspect, in one implementation, the step of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes:

[0018] When the battery branch is fully charged, the number of cells in the fully charged battery branch whose voltage exceeds the terminal drop voltage and the time when the cell voltage exceeds the terminal drop voltage are obtained;

[0019] Based on the time when the cell voltage exceeds the terminal drop voltage and the charging current, the balanced power of the cells that need to be balanced in the fully charged battery branch is calculated in combination with a preset algorithm.

[0020] In combination with the first aspect, in one implementation, the step of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes:

[0021] For the current battery branch, if the first number is not less than the second number, the number of cells to be balanced in the current battery branch is the second number, wherein the cells in the current battery branch are sorted in the order of time when the terminal drop current voltage is exceeded, and the cells to be balanced in the current battery branch are the first to second number of cells;

[0022] The preset algorithm is used to calculate the balanced power of the cells that need to be balanced in the current battery branch:

[0023]

[0024] Among them, Q n Indicates the equalization capacity of the nth cell to be equalized in the current battery branch, I indicates the charging current, t n It indicates the time when the terminal drop current voltage of the nth battery cell exceeds the terminal drop current voltage after the cells in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the terminal drop current voltage, t n+1 Indicates the time when the terminal drop current voltage of the n+1th battery cell exceeds the limit after the batteries in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the limit;

[0025] Under the discharge condition of the battery pack, the cells to be balanced are discharged according to the calculated balanced power of the cells to be balanced to achieve power balance;

[0026] The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

[0027] In combination with the first aspect, in one implementation, the step of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes:

[0028] For the current battery branch, if the first number is less than the second number, the number of cells to be balanced in the current battery branch is the first number, wherein the cells in the current battery branch are sorted in the order of time when the terminal drop current voltage is exceeded, and the cells to be balanced in the current battery branch are the first to the first number of cells;

[0029] The preset algorithm is used to calculate the balanced power of the cells that need to be balanced in the current battery branch:

[0030]

[0031] Among them, Q m represents the equalization capacity of the mth cell to be equalized in the current battery branch, I represents the charging current, t mIt indicates the time when the terminal drop current voltage of the mth battery cell exceeding the terminal drop current voltage exceeds the terminal drop current voltage after the battery cells in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the terminal drop current voltage, and T indicates the full charge time of the current battery branch;

[0032] Under the discharge condition of the battery pack, the cells to be balanced are discharged according to the calculated balanced power of the cells to be balanced to achieve power balance;

[0033] The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

[0034] In combination with the first aspect, in one implementation, under the discharge condition of the battery pack, discharging the cells to be balanced according to the calculated balanced power of the cells to be balanced to achieve power balancing specifically includes:

[0035] Record the number of the battery cells to be balanced and the balanced power of the battery cells to be balanced into the NVM;

[0036] Under the discharge condition of the battery pack, the BMS reads the data recorded in the NVM and turns on the balancing circuit to perform balancing on the cells that need to be balanced. When the current cell's executed balancing power is greater than or equal to the required balancing power, the current cell's power balancing is completed. The calculation method of the cell's executed balancing power is:

[0037]

[0038] Wherein, Q represents the executed balancing power of the battery cell, I1 represents the balancing current of the balancing circuit, t1 represents the balancing circuit on time, and t2 represents the balancing circuit off time.

[0039] In a second aspect, an embodiment of the present application provides a balancing device for a multi-branch battery system, the balancing device for the multi-branch battery system comprising:

[0040] A judgment module, which is used to obtain the SOC range difference between the battery branches during the power battery charging configuration stage, and judge, if the range difference is not less than the set percentage, drive the first execution module to work, if the range difference is less than the set percentage, drive the second execution module to work;

[0041] The first execution module is used to adopt a one-by-one convergence charging method for the battery branches, and perform fast charging after all the battery branches are converged, and calculate the amount of electricity that needs to be balanced in the cells of the fully charged battery branches based on a preset algorithm to achieve electricity balancing;

[0042] The second execution module controls all battery branches to perform fast charging at the same time, and calculates the amount of electricity that needs to be balanced in the cells in the fully charged battery branches based on a preset algorithm to achieve electricity balance.

[0043] In a third aspect, an embodiment of the present application provides a balancing device for a multi-branch battery system, characterized in that the balancing device for the multi-branch battery system comprises a processor, a memory, and a balancing program for the multi-branch battery system stored in the memory and executable by the processor, wherein when the balancing program for the multi-branch battery system is executed by the processor, the steps of the balancing method for the multi-branch battery system described above are implemented.

[0044] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, characterized in that a balancing program for a multi-branch battery system is stored on the computer-readable storage medium, wherein when the balancing program for the multi-branch battery system is executed by a processor, the steps of the balancing method for the multi-branch battery system described above are implemented.

[0045] The beneficial effects brought by the technical solution provided by the embodiments of the present application include:

[0046] For a multi-branch parallel battery system, when there is a large difference in charge between battery branches, the charge of each battery branch is balanced by charging the battery branches one by one, and then the balancing logic is started to balance the charge of the single cells on the same battery branch. When the charge difference between the battery branches is small, the balancing logic is directly started to balance the charge of the single cells on the same battery branch. This can effectively solve the problem of unbalanced charge between branches of a multi-branch parallel battery pack. At the same time, the BMS balancing start and stop conditions are determined by calculating the charge instead of the single cell voltage, thereby improving the accuracy of balancing. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A flow chart of a method for balancing a multi-branch battery system of the present application;

[0048] Figure 2 This is a functional module diagram of a balancing device for a multi-branch battery system of the present application;

[0049] Figure 3 This is a schematic diagram of the hardware structure of the equalization device of the multi-branch battery system of the present application. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0052] On the first aspect, the embodiments of the present application provide a balancing method for a multi-branch battery system, which is used to solve the problem that the difference in charge between battery branches is large and it is difficult to complete the balancing well with only the balancing circuit, and the single cell voltage cannot fully represent the difference in charge between the single cells. Using the single cell voltage as the BMS balancing start and stop condition may cause some single cells with lower charge to be discharged by the balanced charge, while some single cells with higher charge are not balanced.

[0053] In one embodiment, referring to Figure 1 , Figure 1 This is a flow chart of the equalization method of the multi-branch battery system of the present application. Figure 1 As shown, the balancing method of the multi-branch battery system includes:

[0054] S1: In the power battery charging configuration stage, the SOC (State of Charge) range between the battery branches is obtained and judged. If the range is not less than the set percentage, it goes to S2; if the range is less than the set percentage, it goes to S3;

[0055] S2: The battery branches are charged one by one, and fast charging is performed after all the battery branches are charged. The power required to be balanced in the fully charged battery branches is calculated based on a preset algorithm to achieve power balancing;

[0056] S3: Control all battery branches to perform fast charging at the same time, calculate the amount of electricity that needs to be balanced in the fully charged battery branches based on a preset algorithm, and achieve power balance. For step S3, when it is determined that the extreme difference is less than the set percentage, close the negative relays of all battery branches, so that all battery branches can be fast charged at the same time.

[0057] First of all, it should be explained that the battery balancing of the multi-branch parallel battery system is divided into two parts. One is the imbalance of power between the battery branches of the parallel battery pack due to various reasons, and the other is the imbalance of power of the battery cells (single cell) on the battery branch.

[0058] Normally, the balancing current that the balancing circuit can withstand is mostly 100mA to 200mA. If there is a large difference in power between the battery branches of a parallel battery pack, it is obviously inappropriate to still use the balancing circuit for balancing. Therefore, for a multi-branch parallel battery system, when the power difference between the battery branches is large, the battery branches are charged one by one to balance the power of each battery branch, and when the power difference between the battery branches is small, the balancing circuit is started to balance the power of the single cells on the same battery branch.

[0059] Furthermore, in one embodiment, obtaining the SOC range between battery branches in the power battery charging configuration stage specifically includes:

[0060] S101: obtaining the SOC of each battery branch in the power battery charging configuration stage;

[0061] S102: Based on the acquired SOC of the battery branch, calculate the SOC range between the battery branches.

[0062] Specifically, in the charging configuration stage of the power battery, the SOC of each battery branch is obtained, and then based on the SOC range difference between the battery branches, for example, when the SOC range difference between the battery branches is less than 10%, step S3 is executed, and when the SOC range difference between the battery branches is not less than 10%, step S2 is executed.

[0063] Furthermore, in one embodiment, the battery branches are charged one by one by merging currents, and fast charging is performed after all the battery branches are merged, specifically including:

[0064] S201: Acquire the battery branch with the lowest SOC and the battery branch with the second lowest SOC, close the negative relay of the battery branch with the lowest SOC, and charge the battery branch based on the standard fast charging method;

[0065] S202: Real-time acquisition of the SOC of the battery branch with the lowest SOC, and summing it with the preset percentage SOC, to determine whether the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC:

[0066] If yes, a smaller charging current of a set value is requested to charge the battery branches one by one, and after all the battery branches are charged, all the battery branches are fast charged based on the standard fast charging method;

[0067] If not, continue to charge the battery branch with the lowest SOC, then obtain the SOC of the battery branch with the lowest SOC again, and sum it with the preset percentage SOC until the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC, then request a smaller charging current of the set value, converge and charge the battery branches one by one, and after all battery branches are converged, fast charge all battery branches based on the standard fast charging method.

[0068] Specifically, when the battery branch with the lowest SOC is normally fast charged, the SOC of the battery branch with the lowest SOC is obtained in real time, and then 5% is added to determine whether the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC. If not, the battery branch with the lowest SOC continues to be normally fast charged until the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC. After that, a smaller charging current (the charging current is less than 5A) is requested to converge and charge the battery branches one by one, and after all the battery branches are converged, all the battery branches are fast charged based on the standard fast charging method.

[0069] Furthermore, in one embodiment, the amount of electricity that needs to be balanced in the cells of the fully charged battery branch is calculated based on a preset algorithm to achieve electricity balancing, specifically including:

[0070] S41: when the battery branch is fully charged, obtaining the number of cells in the fully charged battery branch whose voltage exceeds the terminal drop-current voltage, and the time when the cell voltage exceeds the terminal drop-current voltage;

[0071] It should be noted that power batteries will adopt a terminal current reduction strategy at the end of charging, that is, gradually reduce the charging current when the battery is close to full charge to avoid overcharging and extend the battery life. For the purpose of protecting the battery cells, when the maximum single cell voltage on a single battery branch reaches the full charge voltage, the battery branch is considered fully charged. When the battery is close to full charge and the charging current needs to be gradually reduced, the voltage at this time is the terminal current reduction voltage.

[0072] Because in the final stage of charging, even for lithium iron phosphate batteries, the terminal voltage of the cell can better reflect the SOC difference between the single cells, so it can be considered that the single cell whose voltage reaches the terminal current reduction voltage first will be charged with more electricity during the period from the terminal current reduction to full charge.

[0073] Since the power of the battery pack single cell conforms to the normal distribution, and the probability of the value distribution in (μ-2σ, μ+2σ) is 0.9544, this application calculates the extra power of the 5% number of cells that first pass the terminal drop voltage on each battery branch, and starts the balancing power for balancing when the balancing conditions are met. If the cell balancing effect is not good when the number is selected as 5%, it can also be adjusted according to the actual situation.

[0074] S42: Based on the time when the voltage of the battery cell exceeds the terminal drop voltage and the charging current, the balanced power of the battery cells to be balanced in the fully charged battery branch is calculated in combination with a preset algorithm. For a battery branch, when any battery branch is fully charged, the balanced power of the battery cells to be balanced in the battery branch is calculated.

[0075] Specifically, for the cells of a single battery branch, when the voltage of a cell exceeds the terminal drop-current voltage, the moment when the voltage of the cell exceeds the terminal drop-current voltage is recorded.

[0076] Furthermore, based on a preset algorithm, the amount of electricity that needs to be balanced in the cells of the fully charged battery branch is calculated to achieve electricity balancing, specifically including:

[0077] S501: For the current battery branch, if the first number is not less than the second number, the number of cells to be balanced in the current battery branch is the second number, wherein the cells in the current battery branch are sorted in the order of time when they exceed the terminal drop current voltage, and the cells to be balanced in the current battery branch are the first to second number of cells (that is, after the current battery branch is fully charged, the cells that exceed the terminal drop current voltage in the current battery branch are sorted in the order of time when they exceed the terminal drop current voltage, and the cells to be balanced in the current battery branch are the first to second number of cells);

[0078] S502: Calculate the equalization power of the cells to be equalized in the current battery branch using a preset algorithm:

[0079]

[0080] Among them, Q n Indicates the equalization capacity of the nth cell to be equalized in the current battery branch, I indicates the charging current, t n It indicates the time when the terminal drop current voltage of the nth battery cell exceeds after the batteries in the current battery branch are sorted in the order of time when they exceed the terminal drop current voltage (that is, after the current battery branch is fully charged, the terminal drop current voltage of the nth battery cell exceeds the time after the batteries in the current battery branch that exceed the terminal drop current voltage are sorted in the order of time when they exceed the terminal drop current voltage), t n+1 Indicates the time when the terminal drop current voltage of the n+1th battery cell exceeds the limit after the batteries in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the limit;

[0081] In actual applications, for the current battery branch, the time when the terminal drop current voltage of the first battery cell exceeding the terminal drop current voltage is exceeded is recorded as t1, the time when the terminal drop current voltage of the second battery cell exceeding the terminal drop current voltage is recorded as t2, and so on;

[0082] S503: Under the discharge condition of the battery pack, according to the calculated balanced power of the battery cells to be balanced, the battery cells to be balanced are discharged to achieve power balance;

[0083] The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

[0084] Specifically, when the first number is greater than or equal to the second number, it is necessary to balance the power of the first to the second number of cells in the current battery branch in the order of time when the terminal current reduction voltage is exceeded to achieve power balance.

[0085] Furthermore, based on a preset algorithm, the amount of electricity that needs to be balanced in the cells of the fully charged battery branch is calculated to achieve electricity balancing, specifically including:

[0086] S511: For the current battery branch, if the first number is less than the second number, the number of cells to be balanced in the current battery branch is the first number, wherein the cells in the current battery branch are sorted in the order of time when they exceed the terminal drop current voltage, and the cells to be balanced in the current battery branch are the first to the first number of cells (that is, after the current battery branch is fully charged, the cells that exceed the terminal drop current voltage in the current battery branch are sorted in the order of time when they exceed the terminal drop current voltage, and the cells to be balanced in the current battery branch are the first to the first number of cells);

[0087] S512: Calculate the balanced power of the cells to be balanced in the current battery branch using a preset algorithm:

[0088]

[0089] Among them, Q m represents the equalization capacity of the mth cell to be equalized in the current battery branch, I represents the charging current, t m It indicates the time when the terminal current reduction voltage of the mth battery cell exceeding the terminal current reduction voltage exceeds after the batteries in the current battery branch are sorted according to the time sequence of exceeding the terminal current reduction voltage (that is, after the current battery branch is fully charged, the terminal current reduction voltage of the mth battery cell exceeds the time sequence after the batteries in the current battery branch exceeding the terminal current reduction voltage are sorted), and T indicates the full charge time of the current battery branch;

[0090] S513: Under the discharge condition of the battery pack, according to the calculated balanced power of the battery cells to be balanced, the battery cells to be balanced are discharged to achieve power balance;

[0091] The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

[0092] Specifically, when the first number is smaller than the second number, it is necessary to balance the power of the first battery cell to the first number of battery cells in the current battery branch according to the time sequence of exceeding the terminal current reduction voltage to achieve power balance.

[0093] Furthermore, under the discharge condition of the battery pack, the cells to be balanced are discharged according to the calculated balanced power of the cells to be balanced to achieve power balance, which specifically includes:

[0094] S61: Recording the serial number of the battery cell to be balanced and the balanced power of the battery cell to be balanced into NVM (Non-Volatile Memory);

[0095] Specifically, at the stage of reducing the current from the end to full charge, the cells that need to be balanced on each battery branch are selected according to the above strategy, and the numbers of the cells that need to be balanced and the balanced power of the cells that need to be balanced are recorded in the NVM;

[0096] S62: Under the discharge condition of the battery pack, the BMS (Battery Management System) reads the data recorded in the NVM and turns on the balancing circuit to perform balancing on the cells that need to be balanced. When the current cell's balancing power is greater than or equal to the balancing power required, the current cell's power balancing is completed. The calculation method of the balancing power of the cell is as follows:

[0097]

[0098] Wherein, Q represents the executed balancing power of the battery cell, I1 represents the balancing current of the balancing circuit, t1 represents the balancing circuit on time, and t2 represents the balancing circuit off time.

[0099] The balancing method for a multi-branch battery system of an embodiment of the present application, for a multi-branch parallel battery system, when there is a large difference in charge between battery branches, the charge of each battery branch is balanced by charging the battery branches one by one, and then the balancing logic is started to balance the charge of the single cells on the same battery branch; and when the charge difference between the battery branches is small, the balancing logic is directly started to balance the charge of the single cells on the same battery branch. This can effectively solve the problem of unbalanced charge between branches of a multi-branch parallel battery pack, and at the same time, the BMS balancing start and stop conditions are determined by calculating the charge instead of the single cell voltage, thereby improving the accuracy of balancing.

[0100] In a second aspect, an embodiment of the present application further provides a balancing device for a multi-branch battery system.

[0101] In one embodiment, referring to Figure 2 , Figure 2 This is a functional module diagram of the balancing device of the multi-branch battery system of the present application. Figure 2 As shown, the balancing device of the multi-branch battery system includes: a judgment module, a first execution module, and a second execution module.

[0102] The judgment module is used to obtain the SOC extreme difference between battery branches during the power battery charging configuration stage, and judge, if the extreme difference is not less than the set percentage, then drive the first execution module to work, if the extreme difference is less than the set percentage, then drive the second execution module to work; the first execution module is used to adopt a one-by-one convergence charging method for the battery branches, and perform fast charging after all battery branches are merged, calculate the amount of electricity that needs to be balanced in the battery cells in the fully charged battery branch based on a preset algorithm, and achieve electricity balance; the second execution module controls all battery branches to perform fast charging at the same time, calculates the amount of electricity that needs to be balanced in the battery cells in the fully charged battery branch based on a preset algorithm, and achieves electricity balance.

[0103] The functions of each module in the equalization device for the multi-branch battery system described above correspond to the steps in the embodiment of the equalization method for the multi-branch battery system described above, and their functions and implementation processes are not described in detail here.

[0104] In a third aspect, an embodiment of the present application provides a balancing device for a multi-branch battery system. The balancing device for the multi-branch battery system may be a device with data processing function, such as a personal computer (PC), a laptop computer, or a server.

[0105] Reference Figure 3 , Figure 3 The hardware structure diagram of the equalization device of the multi-branch battery system involved in the embodiment of the present application is shown in FIG. In the embodiment of the present application, the equalization device of the multi-branch battery system may include a processor, a memory, a communication interface and a communication bus.

[0106] The communication bus may be of any type and is used to interconnect the processor, the memory, and the communication interface.

[0107] The communication interface includes input / output (I / O) interface, physical interface and logical interface, etc., which are used to realize the interconnection of devices inside the balancing device of the multi-branch battery system, and the interface used to realize the interconnection between the balancing device of the multi-branch battery system and other devices (such as other computing devices or user devices). The physical interface can be an Ethernet interface, a fiber optic interface, an ATM interface, etc.; the user device can be a display, a keyboard, etc.

[0108] The memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0109] The processor may be a general-purpose processor, which may call the equalization program of the multi-branch battery system stored in the memory and execute the equalization method of the multi-branch battery system provided in the embodiment of the present application. For example, the general-purpose processor may be a central processing unit (CPU). The method executed when the equalization program of the multi-branch battery system is called may refer to the various embodiments of the equalization method of the multi-branch battery system of the present application, which will not be repeated here.

[0110] Those skilled in the art will understand that Figure 3 The hardware structure shown in the figure does not constitute a limitation on the present application, and may include more or less components than shown in the figure, or combine certain components, or arrange the components differently.

[0111] In a fourth aspect, an embodiment of the present application also provides a computer-readable storage medium.

[0112] The computer-readable storage medium of the present application stores a balancing program for a multi-branch battery system, wherein when the balancing program for the multi-branch battery system is executed by a processor, the steps of the balancing method for the multi-branch battery system as described above are implemented.

[0113] The method implemented when the balancing program of the multi-branch battery system is executed can refer to the various embodiments of the balancing method of the multi-branch battery system of the present application, which will not be described in detail here.

[0114] It should be noted that the serial numbers of the above-mentioned embodiments of the present application are only for description and do not represent the advantages or disadvantages of the embodiments.

[0115] The terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. The terms "first", "second" and "third" are used to distinguish different objects, etc., and do not represent a sequence, nor do they limit "first", "second" and "third" to different types.

[0116] In the description of the embodiments of the present application, "exemplary", "for example" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary", "for example" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary", "for example" or "for example" is intended to present related concepts in a specific way.

[0117] In the description of the embodiments of the present application, unless otherwise specified, “ / ” means or, for example, A / B can mean A or B; the “and / or” in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, “multiple” refers to two or more than two.

[0118] In some processes described in the embodiments of the present application, multiple operations or steps that appear in a specific order are included, but it should be understood that these operations or steps may not be executed in the order in which they appear in the embodiments of the present application or in parallel, and the sequence number of the operation is only used to distinguish the different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed in sequence or in parallel, and these operations or steps may be combined.

[0119] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application is essentially or the part that contributes to the prior art can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, disk, CD) as described above, and includes a number of instructions for a terminal device to execute the methods described in each embodiment of the present application.

[0120] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method for balancing a multi-branch battery system, characterized in that: The balancing method of the multi-branch battery system comprises: In the power battery charging configuration stage, the SOC range between the battery branches is obtained and judged: If the extreme difference is not less than the set percentage, the battery branches are charged one by one, and fast charging is performed after all battery branches are connected. The power required to be balanced in the fully charged battery branches is calculated based on the preset algorithm to achieve power balancing; If the extreme difference is less than the set percentage, all battery branches are controlled to perform fast charging at the same time, and the power required to be balanced in the cells in the fully charged battery branch is calculated based on the preset algorithm to achieve power balance.

2. A method for balancing a multi-branch battery system as claimed in claim 1, characterized in that: The obtaining of the SOC range between the battery branches in the power battery charging configuration stage specifically includes: Obtain the SOC of each battery branch during the power battery charging configuration stage; Based on the acquired SOC of the battery branch, the SOC range between the battery branches is calculated.

3. A method for balancing a multi-branch battery system as claimed in claim 1, characterized in that: The battery branches are charged one by one by merging current, and fast charging is performed after all the battery branches are charged, which specifically includes: Obtaining the battery branch with the lowest SOC and the battery branch with the second lowest SOC, closing the negative relay of the battery branch with the lowest SOC, and charging the battery branch based on the standard fast charging method; The SOC of the battery branch with the lowest SOC is obtained in real time, and after summing it with the preset percentage SOC, it is determined whether the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC: If yes, a smaller charging current of a set value is requested to charge the battery branches one by one, and after all the battery branches are charged, all the battery branches are fast charged based on the standard fast charging method; If not, continue to charge the battery branch with the lowest SOC, then obtain the SOC of the battery branch with the lowest SOC again, and sum it with the preset percentage SOC until the summed SOC value is greater than the SOC of the battery branch with the second lowest SOC, then request a smaller charging current of the set value, converge and charge the battery branches one by one, and after all battery branches are converged, fast charge all battery branches based on the standard fast charging method.

4. A method for balancing a multi-branch battery system as claimed in claim 1, characterized in that: The method of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes: When the battery branch is fully charged, the number of cells in the fully charged battery branch whose voltage exceeds the terminal drop-down voltage and the time when the cell voltage exceeds the terminal drop-down voltage are obtained; Based on the time when the cell voltage exceeds the terminal drop voltage and the charging current, the balanced power of the cells that need to be balanced in the fully charged battery branch is calculated in combination with a preset algorithm.

5. A method for balancing a multi-branch battery system as claimed in claim 4, characterized in that: The method of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes: For the current battery branch, if the first number is not less than the second number, the number of cells to be balanced in the current battery branch is the second number, wherein the cells in the current battery branch are sorted in the order of time when the terminal drop current voltage is exceeded, and the cells to be balanced in the current battery branch are the first to second number of cells; The preset algorithm is used to calculate the balanced power of the cells that need to be balanced in the current battery branch: Among them, Q n Indicates the equalization capacity of the nth cell to be equalized in the current battery branch, I indicates the charging current, t n It indicates the time when the terminal drop current voltage of the nth battery cell exceeds the terminal drop current voltage after the cells in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the terminal drop current voltage, t n+1 Indicates the time when the terminal drop current voltage of the n+1th battery cell exceeds the limit after the batteries in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the limit; Under the discharge condition of the battery pack, the cells to be balanced are discharged according to the calculated balanced power of the cells to be balanced to achieve power balance; The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

6. A method for balancing a multi-branch battery system as claimed in claim 4, characterized in that: The method of calculating the amount of electricity to be balanced in the cells in the fully charged battery branch based on a preset algorithm to achieve electricity balancing specifically includes: For the current battery branch, if the first number is less than the second number, the number of cells to be balanced in the current battery branch is the first number, wherein the cells in the current battery branch are sorted in the order of time when the terminal drop current voltage is exceeded, and the cells to be balanced in the current battery branch are the first to the first number of cells; The preset algorithm is used to calculate the balanced power of the cells that need to be balanced in the current battery branch: Among them, Q m represents the equalization capacity of the mth cell to be equalized in the current battery branch, I represents the charging current, t m It indicates the time when the terminal drop current voltage of the mth battery cell exceeding the terminal drop current voltage exceeds the terminal drop current voltage after the battery cells in the current battery branch are sorted in the order of the time when the terminal drop current voltage exceeds the terminal drop current voltage, and T indicates the full charge time of the current battery branch; Under the discharge condition of the battery pack, the cells to be balanced are discharged according to the calculated balanced power of the cells to be balanced to achieve power balance; The first number is the number of cells whose voltage exceeds the terminal current reduction voltage when the battery branch is fully charged, and the second number is the number of the first preset percentage of the total number of cells in the battery branch.

7. A method for balancing a multi-branch battery system as claimed in claim 5 or 6, characterized in that: Under the discharge condition of the battery pack, discharging the cells to be balanced according to the calculated balanced power of the cells to be balanced to achieve power balance specifically includes: Record the number of the battery cells to be balanced and the balanced power of the battery cells to be balanced into the NVM; Under the discharge condition of the battery pack, the BMS reads the data recorded in the NVM and turns on the balancing circuit to perform balancing on the cells that need to be balanced. When the current cell's executed balancing power is greater than or equal to the required balancing power, the current cell's power balancing is completed. The calculation method of the cell's executed balancing power is: Wherein, Q represents the executed balancing power of the battery cell, I1 represents the balancing current of the balancing circuit, t1 represents the balancing circuit on time, and t2 represents the balancing circuit off time.

8. A balancing device for a multi-branch battery system, characterized in that: The balancing device of the multi-branch battery system comprises: A judgment module, which is used to obtain the SOC range difference between the battery branches during the power battery charging configuration stage, and judge, if the range difference is not less than the set percentage, drive the first execution module to work, if the range difference is less than the set percentage, drive the second execution module to work; The first execution module is used to adopt a one-by-one convergence charging method for the battery branches, and perform fast charging after all the battery branches are converged, and calculate the amount of electricity that needs to be balanced in the cells of the fully charged battery branches based on a preset algorithm to achieve electricity balancing; The second execution module controls all battery branches to perform fast charging at the same time, and calculates the amount of electricity that needs to be balanced in the cells in the fully charged battery branches based on a preset algorithm to achieve electricity balance.

9. A balancing device for a multi-branch battery system, characterized in that: The balancing device of the multi-branch battery system includes a processor, a memory, and a balancing program of the multi-branch battery system stored in the memory and executable by the processor, wherein when the balancing program of the multi-branch battery system is executed by the processor, the steps of the balancing method of the multi-branch battery system as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a balancing program for a multi-branch battery system, wherein when the balancing program for the multi-branch battery system is executed by a processor, the steps of the balancing method for a multi-branch battery system according to any one of claims 1 to 7 are implemented.

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