Battery capacity balancing methods, systems, devices, and media based on capacity differences

Abstract

This invention provides a battery capacity balancing method, system, device, and medium based on capacity differences, relating to the field of new energy batteries. The method includes: acquiring discharge data during vehicle operation; the discharge data including current, voltage, and time during the discharge process; determining the battery capacity at each moment during vehicle operation based on the current and time; determining the open-circuit voltage of each battery cell at each moment based on a constructed battery model using a parameter identification method; determining the capacity difference between battery cells based on the open-circuit voltage and the battery capacity; formulating a balancing strategy based on the capacity differences between the positioned capacities of each battery cell; and performing balancing control on each battery cell in the battery system according to the balancing strategy. This invention can achieve capacity balancing between battery cells.

Description

Technical Field

[0001] This invention relates to the field of new energy batteries, and in particular to battery capacity balancing methods, systems, devices and media based on capacity differences. Background Technology

[0002] In battery systems, differences in internal resistance, self-discharge rate, temperature, coulombic efficiency, and other factors among individual battery cells often lead to differences in the state of charge (SOC) among the cells, resulting in an imbalance in battery capacity. When the battery system is fully charged, only one battery cell reaches a fully charged state, while the others are not fully charged. The same applies when discharging.

[0003] To address the issue of reduced system capacity caused by this imbalance, the battery management system (BMS) is equipped with passive or active balancing, which adjusts the capacity of each individual battery cell to achieve a balanced state in the battery system.

[0004] Currently, methods such as energy difference, consistency coefficient, or SOC are commonly used to adjust the capacity between individual battery cells for equalization control. However, using energy difference as the equalization control parameter, especially in lithium iron phosphate battery systems, is problematic because the energy difference caused by inconsistent internal resistance accounts for a larger proportion of the calculation, easily leading to incorrect equalization. While equalizing individual cells using the consistency coefficient, the calculation method for the consistency coefficient is not explained, and the consistency coefficient does not accurately reflect the battery capacity. When using battery SOC as the equalization variable, it is difficult to accurately estimate the SOC of each individual cell for lithium iron phosphate batteries, making it difficult to accurately reflect the battery capacity. Therefore, for lithium iron phosphate batteries, all the above methods fail to accurately reflect the battery capacity and cannot achieve proper capacity equalization. Summary of the Invention

[0005] The purpose of this invention is to provide a battery capacity balancing method, system, device, and medium based on capacity differences to solve the problem of battery capacity balancing.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A battery capacity equalization method based on capacity differences includes:

[0008] Acquire discharge data during vehicle operation; the discharge data includes current, voltage, and time during the discharge process;

[0009] The battery capacity at each moment during the vehicle's operation is determined based on the current and the time.

[0010] Based on the established battery model, the open-circuit voltage of each battery cell at each moment is determined using the parameter identification method according to the voltage.

[0011] The capacity difference between individual battery cells is determined based on the open-circuit voltage and the battery capacity.

[0012] A balancing strategy is developed based on the capacity differences between the positioning capacities of each battery cell;

[0013] The equalization strategy is used to perform equalization control on each individual battery cell in the battery system.

[0014] Optionally, the capacity difference between individual battery cells is determined based on the open-circuit voltage and the battery capacity, specifically including:

[0015] Based on the relationship between the open-circuit voltage and the battery capacity, determine the trend curve of the open-circuit voltage changing with the battery capacity;

[0016] The inflection point of the open-circuit voltage in the middle section of the discharge is located based on the trend curve.

[0017] Determine the positioning capacity of each battery cell corresponding to the inflection point position;

[0018] The capacity difference between individual battery cells is determined based on the stated positioning capacity.

[0019] Optionally, the capacity difference between individual battery cells is determined based on the open-circuit voltage and the battery capacity, specifically including:

[0020] The battery cell that triggers the charging cutoff voltage is selected as the reference battery cell, and the open-circuit voltage of the reference battery cell is used as the reference open-circuit voltage.

[0021] Calculate the difference between the open-circuit voltage of all individual battery cells and the reference open-circuit voltage;

[0022] The starting and ending points of the peaks in the relationship curve between the voltage difference and the battery capacity are determined based on the relationship curve.

[0023] The capacity difference of each battery cell relative to the reference battery cell is determined based on the battery capacity corresponding to the start and end points.

[0024] Optionally, a balancing strategy can be formulated based on the capacity difference between the positioning capacities of each battery cell, specifically including: an active balancing control strategy;

[0025] The active balancing control strategy is to select a balancing path with the goal of minimizing capacity loss.

[0026] According to the aforementioned balancing path, capacity is transferred from high-capacity battery cells to low-capacity battery cells.

[0027] Optionally, a balancing strategy can be formulated based on the capacity difference between the positioning capacities of each battery cell, specifically including: a passive balancing control strategy;

[0028] The passive equalization control strategy is to activate the internal resistance consumption of high-capacity battery cells until the capacity reaches or approaches that of the lowest-capacity battery cell, while maintaining the capacity difference at 0 or less than a set capacity threshold.

[0029] A battery capacity balancing system based on capacity differences includes:

[0030] The discharge data acquisition module is used to acquire discharge data during vehicle operation; the discharge data includes current, voltage, and time during the discharge process.

[0031] A capacity determination module is used to determine the battery capacity at each moment during the vehicle's operation based on the current and the time.

[0032] The open-circuit voltage determination module is used to determine the open-circuit voltage of each battery cell at each moment based on the established battery model and using the parameter identification method.

[0033] A capacity difference determination module is used to determine the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity.

[0034] The balancing strategy formulation module is used to formulate a balancing strategy based on the capacity differences between the positioning capacities of each battery cell.

[0035] The equalization control module is used to perform equalization control on each battery cell in the battery system according to the equalization strategy.

[0036] Optional, the capacity difference determination module specifically includes:

[0037] The trend curve determination unit is used to determine the trend curve of the open circuit voltage as a function of the battery capacity based on the correspondence between the open circuit voltage and the battery capacity.

[0038] The inflection point location determination unit is used to locate the inflection point of the open circuit voltage in the middle segment of the discharge based on the change trend curve.

[0039] A positioning capacity determination unit is used to determine the positioning capacity of each battery cell corresponding to the inflection point position;

[0040] A capacity difference determination unit is used to determine the capacity difference between individual battery cells based on the positioning capacity.

[0041] Optional, the capacity difference determination module specifically includes:

[0042] The reference open-circuit voltage determination unit is used to select the battery cell that triggers the charging cut-off voltage as the reference battery cell, and to use the open-circuit voltage of the reference battery cell as the reference open-circuit voltage.

[0043] The open-circuit voltage difference calculation unit is used to calculate the difference between the open-circuit voltage of all battery cells and the reference open-circuit voltage.

[0044] The start and end point determination unit is used to determine the start and end points of the peaks in the relationship curve based on the relationship curve between the open circuit voltage difference and the battery capacity.

[0045] A capacity difference determination unit is used to determine the capacity difference of each battery cell relative to the reference battery cell based on the battery capacity corresponding to the start point and the end point.

[0046] An electronic device includes a memory and a processor, the memory storing a computer program and the processor running the computer program to cause the electronic device to perform the above-described battery capacity equalization method based on capacity differences.

[0047] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described battery capacity equalization method based on capacity differences.

[0048] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: Based on the discharge data during vehicle operation, the present invention identifies the capacity differences between individual battery cells, formulates a balancing strategy to balance and control each battery cell in the battery system, and performs balancing control based on capacity differences, eliminating the step of solving the SOC of each battery cell, solving the problem of poor performance caused by using pressure difference judgment, avoiding the inaccuracy caused by complex SOC estimation, improving the accuracy of the algorithm, and realizing capacity balancing between battery cells. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 The flowchart of the battery capacity balancing method based on capacity difference provided by the present invention is shown below.

[0051] Figure 2 The curve showing the change trend of open-circuit voltage with battery capacity provided by the present invention. Detailed Implementation

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0053] The purpose of this invention is to provide a battery capacity balancing method, system, device and medium based on capacity differences, which can achieve capacity balancing between individual battery cells.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Example 1

[0056] like Figure 1 As shown, the present invention provides a battery capacity equalization method based on capacity differences, comprising:

[0057] Step 101: Obtain discharge data during vehicle operation; the discharge data includes current, voltage, and time during the discharge process.

[0058] Step 102: Determine the battery capacity at each moment during the vehicle's operation based on the current and the time.

[0059] In practical applications, the battery capacity at each moment during the vehicle's operation is determined using the ampere-hour integration method based on the current and the time. The capacity values ​​at each moment are then sorted according to the time sequence to form a capacity array Q.

[0060] Step 103: Based on the established battery model, the open-circuit voltage of each battery cell at each moment is determined using the parameter identification method according to the voltage.

[0061] In practical applications, the battery model includes equivalent circuit models, fractional-order models, or electrochemical models, etc.

[0062] The parameter identification method includes identification algorithms, which can be any algorithm that can identify OCV, such as the least squares identification algorithm, Kalman filter algorithm, H-infinity algorithm, or intelligent machine learning optimization algorithm.

[0063] Step 104: Determine the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity.

[0064] In practical applications, step 104 specifically includes: determining the trend curve of the change of the open circuit voltage with the battery capacity based on the correspondence between the open circuit voltage and the battery capacity; locating the inflection point of the open circuit voltage in the middle of the discharge segment based on the trend curve; determining the positioning capacity of each battery cell corresponding to the inflection point; and determining the capacity difference between battery cells based on the positioning capacity.

[0065] In practical applications, step 104 specifically includes: selecting the battery cell that triggers the charging cutoff voltage as the reference battery cell, and using the open-circuit voltage of the reference battery cell as the reference open-circuit voltage; calculating the difference between the open-circuit voltage of all battery cells and the reference open-circuit voltage; determining the start and end points of the peaks in the relationship curve between the voltage difference and the battery capacity; and determining the capacity difference of each battery cell relative to the reference battery cell based on the battery capacity corresponding to the start and end points.

[0066] As an optional embodiment of the present invention, such as Figure 2 As shown, the open-circuit voltage corresponds to the capacity array Q. The trend of open-circuit voltage changing with Q is identified, and the inflection point of open-circuit voltage in the middle of the discharge stage (SOC around 50%) is located. This position is marked as L, and the corresponding battery capacity value is marked as Q. L The capacitance value corresponding to each battery cell is marked as Q. L (i), where i is the serial number of the battery cell, L(i+1) is the position corresponding to the (i+1)th battery cell, and L(i) is the position corresponding to the ith battery cell.

[0067] One method for locating the inflection point is to prioritize processing the open circuit voltage (OCV) curve. The OCV curve represents the trend of the open circuit voltage changing with the battery capacity. Processing methods include formula fitting or smoothing, resulting in a result as shown below. Figure 2 The solid curve shown is more conducive to inflection point location. If OCVi itself can easily and accurately identify the inflection point, the above operation can be omitted. The location can be the start position of the inflection point, the middle position, or the end position, ensuring that the selected inflection point positions for all cells remain consistent. When the battery discharge depth is not ideal, the start position of the inflection point can be preferred to reduce the required battery discharge depth. OCVi is the open-circuit voltage of the i-th battery, OCVi+1 is the open-circuit voltage of the (i+1)-th battery, and i is the battery number.

[0068] The capacity Q of the battery cell corresponding to the inflection point. LAnother implementation method for (i) is: by selecting a certain cell as the reference cell, subtracting the open-circuit voltage of the reference cell from the open-circuit voltage of all cells, denoted as Δu oc Identify Δu oc The starting point S and ending point E of the curve corresponding to Q are recorded, and the battery capacities corresponding to the starting point and ending point are Q, respectively. S (i) and Q E (i), Q S (i)-Q E (i) represents the capacity difference between the battery cell and the reference cell.

[0069] Step 105: Develop a balancing strategy based on the capacity differences between the positioning capacities of each battery cell.

[0070] In practical applications, the equilibrium strategy specifically includes: active equilibrium control strategy and passive equilibrium control strategy.

[0071] The active balancing control strategy is as follows: selecting a balancing path with the goal of minimizing capacity loss; and transferring capacity from high-capacity battery cells to low-capacity battery cells according to the balancing path.

[0072] The passive equalization control strategy is as follows: the high-capacity battery cells are activated to consume internal resistance until the capacity reaches or approaches that of the lowest-capacity battery cells, and the capacity difference is kept at 0 or less than a set capacity threshold; wherein, the set capacity threshold can be a percentage of the rated capacity.

[0073] Step 106: Perform equalization control on each battery cell in the battery system according to the equalization strategy.

[0074] In practical applications, comparing the Q values ​​between each individual battery cell L (i) The value is high or low, and the corresponding balancing strategy is executed according to the value to achieve precise balancing control of the battery system.

[0075] This invention utilizes the inflection point of the curve showing the change in open-circuit voltage with battery capacity to locate and identify the capacity differences between individual battery cells, eliminating the need to calculate the state of charge (SOC) of each cell. This solves the problem of poor performance caused by using voltage difference for judgment, avoids the inaccuracy caused by the complexity of SOC estimation, and improves the accuracy of the algorithm.

[0076] Compared to methods that utilize charging data, which require constant current charging to determine the inflection point of the battery (which is difficult to achieve in real-world vehicles), this method has poor versatility in practical applications. This invention avoids using charging data and instead utilizes discharge data to pinpoint the capacity differences between individual cells, making the method more versatile.

[0077] This invention departs from the conventional method of identifying capacity differences by using full charge or discharge end. Instead, it uses the voltage plateau inflection point that appears in the middle of the discharge to locate and identify the capacity differences between individual battery cells. This reduces the reliance on deep battery discharge and eliminates the need to discharge to the low end of the SOC, making it more in line with the actual usage scenarios of vehicles.

[0078] Example 2

[0079] In order to implement the method corresponding to Embodiment 1 above and achieve the corresponding functions and technical effects, a battery capacity balancing system based on capacity differences is provided below.

[0080] A battery capacity balancing system based on capacity differences includes:

[0081] The discharge data acquisition module is used to acquire discharge data during vehicle operation; the discharge data includes current, voltage and time during the discharge process.

[0082] A capacity determination module is used to determine the battery capacity at each moment during the vehicle's operation based on the current and the time.

[0083] The open-circuit voltage determination module is used to determine the open-circuit voltage of each battery cell at each moment based on the established battery model and using parameter identification method.

[0084] The capacity difference determination module is used to determine the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity.

[0085] The balancing strategy formulation module is used to formulate a balancing strategy based on the capacity differences between the positioning capacities of each battery cell.

[0086] The equalization control module is used to perform equalization control on each battery cell in the battery system according to the equalization strategy.

[0087] In practical applications, the capacity difference determination module specifically includes: a trend curve determination unit, used to determine the trend curve of the open circuit voltage changing with the battery capacity based on the correspondence between the open circuit voltage and the battery capacity; an inflection point determination unit, used to locate the inflection point of the open circuit voltage in the middle of the discharge segment based on the trend curve; a positioning capacity determination unit, used to determine the positioning capacity of each battery cell corresponding to the inflection point; and a capacity difference determination unit, used to determine the capacity difference between battery cells based on the positioning capacity.

[0088] In practical applications, the capacity difference determination module specifically includes: a reference open-circuit voltage determination unit, used to select the battery cell that triggers the charging cutoff voltage as the reference battery cell, and use the open-circuit voltage of the reference battery cell as the reference open-circuit voltage; an open-circuit voltage difference calculation unit, used to calculate the difference between the open-circuit voltage of all battery cells and the reference open-circuit voltage; a start and end point determination unit, used to determine the start and end points of the peaks in the relationship curve between the voltage difference and the battery capacity; and a capacity difference determination unit, used to determine the capacity difference of each battery cell relative to the reference battery cell based on the battery capacity corresponding to the start and end points.

[0089] Example 3

[0090] This invention provides an electronic device including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to enable the electronic device to perform the battery capacity equalization method based on capacity differences provided in Embodiment 1.

[0091] In practical applications, the aforementioned electronic devices can be servers.

[0092] In practical applications, electronic devices include: at least one processor, memory, bus, and communication interface.

[0093] The processor, communication interface, and memory communicate with each other via a communication bus.

[0094] A communication interface is used to communicate with other devices.

[0095] The processor is used to execute programs, specifically the methods described in the above embodiments.

[0096] Specifically, the program may include program code, which includes computer operation instructions.

[0097] The processor may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The electronic device may include one or more processors of the same type, such as one or more CPUs; or it may include processors of different types, such as one or more CPUs and one or more ASICs.

[0098] Memory is used to store programs. Memory may include high-speed RAM, and may also include non-volatile memory, such as at least one disk drive.

[0099] Based on the description of the above embodiments, this application provides a storage medium storing computer program instructions thereon, which can be executed by a processor to implement the methods described in any embodiment.

[0100] The battery capacity balancing system based on capacity differences provided in this application exists in various forms, including but not limited to:

[0101] (1) Mobile communication devices: These devices are characterized by their mobile communication capabilities and primarily aim to provide voice and data communication. These terminals include: smartphones (e.g., iPhones), multimedia phones, feature phones, and low-end phones, etc.

[0102] (2) Ultra-mobile personal computer devices: These devices fall under the category of personal computers, possessing computing and processing capabilities, and generally also have mobile internet access capabilities. These terminals include PDAs, MIDs, and UMPCs, such as the iPad.

[0103] (3) Portable entertainment devices: These devices can display and play multimedia content. This category includes: audio and video players (such as iPods), handheld game consoles, e-books, as well as smart toys and portable car navigation devices.

[0104] (4) Other electronic devices with data interaction functions.

[0105] Specific embodiments of the subject matter have now been described. Other embodiments are within the scope of the appended claims. In some cases, the actions described in the claims can be performed in a different order and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing can be advantageous.

[0106] The systems, devices, modules, or units described in the above embodiments can be implemented by computer chips or entities, or by products with certain functions. A typical implementation device is a computer. Specifically, a computer can be, for example, a personal computer, laptop computer, cellular phone, camera phone, smartphone, personal digital assistant, media player, navigation device, email device, game console, tablet computer, wearable device, or any combination of these devices.

[0107] For ease of description, the above apparatus is described by dividing it into various functional units. Of course, in implementing this application, the functions of each unit can be implemented in one or more software and / or hardware components. Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create a machine for implementing the flowchart illustrations and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0109] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0111] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0112] Memory may include non-persistent storage in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0113] Computer-readable media include both permanent and non-permanent, removable and non-removable media that can store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic tape, disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0114] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0115] This application can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform specific transactions or implement specific abstract data types. This application can also be practiced in distributed computing environments where transactions are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0116] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0117] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A battery capacity equalization method based on capacity differences, characterized in that, include: Acquire discharge data during vehicle operation; the discharge data includes current, voltage, and time during the discharge process; The battery capacity at each moment during the vehicle's operation is determined based on the current and the time. Based on the established battery model, the open-circuit voltage of each battery cell at each moment is determined using the parameter identification method according to the voltage. Determining the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity specifically includes: Based on the relationship between the open-circuit voltage and the battery capacity, determine the trend curve of the open-circuit voltage changing with the battery capacity; The inflection point of the open-circuit voltage in the middle section of the discharge is located based on the trend curve. Determine the positioning capacity of each battery cell corresponding to the inflection point position; The capacity difference between individual battery cells is determined based on the stated positioning capacity. A balancing strategy is developed based on the capacity differences between the positioning capacities of each battery cell; The equalization strategy is used to perform equalization control on each individual battery cell in the battery system.

2. The battery capacity equalization method based on capacity differences according to claim 1, characterized in that, Determining the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity specifically includes: The battery cell that triggers the charging cutoff voltage is selected as the reference battery cell, and the open-circuit voltage of the reference battery cell is used as the reference open-circuit voltage. Calculate the difference between the open-circuit voltage of all individual battery cells and the reference open-circuit voltage; The starting and ending points of the peaks in the relationship curve are determined based on the relationship curve between the difference and the battery capacity; The capacity difference of each battery cell relative to the reference battery cell is determined based on the battery capacity corresponding to the start and end points.

3. The battery capacity equalization method based on capacity differences according to claim 1, characterized in that, A balancing strategy is formulated based on the capacity differences between the positioning capacities of each battery cell, specifically including: an active balancing control strategy; The active balancing control strategy is to select a balancing path with the goal of minimizing capacity loss. According to the aforementioned balancing path, capacity is transferred from high-capacity battery cells to low-capacity battery cells.

4. The battery capacity equalization method based on capacity differences according to claim 1, characterized in that, A balancing strategy is formulated based on the capacity differences between the positioning capacities of each battery cell, specifically including: a passive balancing control strategy; The passive equalization control strategy is to activate the internal resistance consumption of high-capacity battery cells until the capacity reaches or approaches that of the lowest-capacity battery cell, while maintaining the capacity difference at 0 or less than a set capacity threshold.

5. A battery capacity balancing system based on capacity differences, characterized in that, include: The discharge data acquisition module is used to acquire discharge data during vehicle operation; the discharge data includes current, voltage, and time during the discharge process. A capacity determination module is used to determine the battery capacity at each moment during the vehicle's operation based on the current and the time. The open-circuit voltage determination module is used to determine the open-circuit voltage of each battery cell at each moment based on the established battery model and using the parameter identification method. A capacity difference determination module is used to determine the capacity difference between individual battery cells based on the open-circuit voltage and the battery capacity. The capacity difference determination module specifically includes: The trend curve determination unit is used to determine the trend curve of the open circuit voltage as a function of the battery capacity based on the correspondence between the open circuit voltage and the battery capacity. The inflection point location determination unit is used to locate the inflection point of the open circuit voltage in the middle segment of the discharge based on the change trend curve. A positioning capacity determination unit is used to determine the positioning capacity of each battery cell corresponding to the inflection point position; A capacity difference determination unit is used to determine the capacity difference between individual battery cells based on the positioning capacity. The balancing strategy formulation module is used to formulate a balancing strategy based on the capacity differences between the positioning capacities of each battery cell. The equalization control module is used to perform equalization control on each battery cell in the battery system according to the equalization strategy.

6. The battery capacity balancing system based on capacity differences according to claim 5, characterized in that, The capacity difference determination module specifically includes: The reference open-circuit voltage determination unit is used to select the battery cell that triggers the charging cut-off voltage as the reference battery cell, and to use the open-circuit voltage of the reference battery cell as the reference open-circuit voltage. The open-circuit voltage difference calculation unit is used to calculate the difference between the open-circuit voltage of all battery cells and the reference open-circuit voltage. The start and end point determination unit is used to determine the start and end points of the peaks in the relationship curve between the voltage difference and the battery capacity. A capacity difference determination unit is used to determine the capacity difference of each battery cell relative to the reference battery cell based on the battery capacity corresponding to the start point and the end point.

7. An electronic device, characterized in that, The device includes a memory and a processor, the memory being used to store a computer program, and the processor running the computer program to cause the electronic device to perform the battery capacity equalization method based on capacity differences as described in any one of claims 1-4.

8. A computer-readable storage medium, characterized in that, It stores a computer program that, when executed by a processor, implements the battery capacity equalization method based on capacity differences as described in any one of claims 1-4.

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