Battery state of health determining method and apparatus, battery management system, and storage medium

Abstract

The present application relates to the technical field of vehicles, and discloses a battery state of health determining method and apparatus, a battery management system, and a storage medium. In the method, the current inherent capacity of each battery cell is first determined on the basis of the current remaining power of each battery cell in a battery system and the current discharge capacity of the battery system, and then the current state of health of the battery system is determined on the basis of the current inherent capacity of each battery cell and a nominal capacity. In view of the above, in the method, during determining the state of health of the battery system, the current data is used, such that the problem of error accumulation over time is avoided, and then the accuracy of determining of the state of health of the battery system can be improved.

Description

Battery health status determination method, device, battery management system and storage medium

[0001] This application claims priority to Chinese patent application No. 202311872603.6 filed on December 29, 2023, entitled “Battery Health Status Determination Method, Device, Battery Management System and Storage Medium,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of vehicle technology, and in particular to a method and device for determining the health status of a battery, a battery management system, and a storage medium. Background Art

[0003] For electric vehicles, after the battery system has been working for a period of time, the capacity of the battery system will decay due to the aging of the battery system. The indicator for judging the aging of the battery system is the health status of the battery system.

[0004] In related technologies, the battery management system mainly records the cumulative capacity flowing into and out of the battery system, converts the capacity into the number of charge and discharge cycles of the battery, and then uses the relationship table between the number of charge and discharge cycles and capacity measured in the laboratory to look up the table to obtain the current capacity of the battery system, and determines the health status of the battery system based on the current capacity of the battery system.

[0005] However, in the process of calculating the cumulative capacity, there will inevitably be capacity errors, and this capacity error will gradually accumulate over time, resulting in a large error in the determined health status of the battery system.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a method, device, battery management system, and storage medium for determining the health status of a battery system, which can improve the accuracy of determining the health status of the battery system. The technical solution is as follows:

[0008] In one aspect, a method for determining a battery health state is provided, the method comprising:

[0009] Obtain the remaining power and nominal capacity of the battery system;

[0010] When it is determined that the battery system meets a detection condition based on the remaining power of the battery system, obtaining a current discharge capacity of the battery system and a voltage of each battery cell, wherein the current discharge capacity of the battery system is the discharge capacity of the battery system up to the present moment after the battery system is fully charged and enters a discharge state, and the battery system includes a plurality of battery cells;

[0011] For each battery cell, determining a current remaining capacity of the battery cell based on the voltage of the battery cell;

[0012] Determining a current inherent capacity of the battery cell based on a current remaining charge of the battery cell and a current discharge capacity of the battery system, where the current inherent capacity of the battery cell represents the capacity of the battery cell after it is fully charged.

[0013] Based on the current inherent capacity of each battery cell and the nominal capacity, a current health state value of the battery system is determined, where the current health state value of the battery system is used to reflect the current health state of the battery system.

[0014] In a possible implementation, determining the current remaining power of the battery cell based on the voltage of the battery cell includes:

[0015] Obtaining the current temperature of the battery cell;

[0016] Determine a target temperature range to which the current temperature of the battery cell belongs;

[0017] determining first relationship data corresponding to the target temperature range, wherein the first relationship data is used to represent a linear relationship between the voltage and the remaining power of the battery cell within the target temperature range;

[0018] The current remaining capacity of the battery cell is determined based on the voltage of the battery cell and the first relationship data.

[0019] In another possible implementation, determining first relationship data corresponding to the target temperature range includes:

[0020] Obtaining a parameter table of the battery cell in the target temperature range, where the parameter table is obtained based on the open circuit voltage and the remaining capacity of the battery cell;

[0021] Determining, based on the parameter table, an open circuit voltage corresponding to a remaining capacity of the battery cell within a first preset range;

[0022] A linear fit is performed on the remaining power of the battery unit within a first preset range and its corresponding open circuit voltage to obtain first relationship data corresponding to the target temperature range.

[0023] In another possible implementation, determining the current inherent capacity of the battery cell based on the current remaining power of the battery cell and the current discharge capacity of the battery system includes:

[0024] Determine a difference between 1 and the current remaining power of the battery cell to obtain a first difference;

[0025] The ratio of the current discharge capacity of the battery system to the first difference is determined to obtain the current inherent capacity of the battery cell.

[0026] In another possible implementation, determining the current state of health value of the battery system based on the current inherent capacity of each battery cell and the nominal capacity includes:

[0027] Determine a ratio of a current intrinsic capacity of each battery cell to the nominal capacity to obtain a current health status value of each battery cell;

[0028] A minimum state-of-health value is determined from the current state-of-health values ​​of the plurality of battery cells, and the minimum state-of-health value is determined as the current state-of-health value of the battery system.

[0029] In another possible implementation, the method further includes:

[0030] When the remaining power of the battery system is within a first preset range, the battery system changes from a static state to a powered-on state, and the time interval between a first timestamp and a second timestamp is greater than a preset time length, it is determined that the battery system meets the detection condition, the first timestamp is the timestamp when the battery system enters the static state, and the second timestamp is the timestamp when the battery system enters the powered-on state.

[0031] In another aspect, a device for determining a battery health state is provided, the device comprising:

[0032] A first acquisition module is used to obtain the remaining power and nominal capacity of the battery system;

[0033] a second acquisition module, configured to, when it is determined based on the remaining power of the battery system that the battery system meets a detection condition, acquire a current discharge capacity of the battery system and a voltage of each battery cell, wherein the current discharge capacity of the battery system is the discharge capacity of the battery system up to the present moment after the battery system is fully charged and enters a discharge state, and the battery system includes a plurality of battery cells;

[0034] A first determining module is configured to determine, for each battery cell, a current remaining capacity of the battery cell based on the voltage of the battery cell;

[0035] a second determining module, configured to determine a current inherent capacity of the battery cell based on a current remaining power of the battery cell and a current discharge capacity of the battery system, wherein the current inherent capacity of the battery cell represents the capacity of the battery cell after it is currently fully charged;

[0036] The third determination module is used to determine the current health state value of the battery system based on the current inherent capacity of each battery cell and the nominal capacity, where the current health state value of the battery system is used to reflect the current health state of the battery system.

[0037] In one possible implementation, the first determination module is used to obtain the current temperature of the battery cell; determine the target temperature range to which the current temperature of the battery cell belongs; determine first relationship data corresponding to the target temperature range, the first relationship data being used to represent the linear relationship between the voltage and the remaining power of the battery cell within the target temperature range; and determine the current remaining power of the battery cell based on the voltage of the battery cell and the first relationship data.

[0038] In another possible implementation, the apparatus further includes:

[0039] a third acquisition module, configured to acquire a parameter table of the battery unit in the target temperature range, wherein the parameter table is obtained based on the open circuit voltage and the remaining power of the battery unit;

[0040] a fourth determining module, configured to determine, based on the parameter table, an open circuit voltage corresponding to a remaining capacity of the battery cell within a first preset range;

[0041] The fitting module is used to perform linear fitting on the remaining power of the battery unit within a first preset range and its corresponding open circuit voltage to obtain first relationship data corresponding to the target temperature range.

[0042] In another possible implementation, the second determination module is used to determine the difference between 1 and the current remaining power of the battery cell to obtain a first difference; determine the ratio of the current discharge capacity of the battery system to the first difference to obtain the current inherent capacity of the battery cell.

[0043] In another possible implementation, the third determination module is used to determine the ratio of the current inherent capacity of each battery cell to the nominal capacity to obtain the current health status value of each battery cell; determine the minimum health status value from the current health status values ​​of the multiple battery cells, and determine the minimum health status value as the current health status value of the battery system.

[0044] In another possible implementation, the apparatus further includes:

[0045] A fifth determination module is configured to determine that the battery system satisfies a detection condition when the remaining power of the battery system is within a first preset range, the battery system changes from a static state to a powered-on state, and the time interval between the first timestamp and the second timestamp is greater than a preset duration, wherein the first timestamp is the timestamp when the battery system enters the static state, and the second timestamp is the timestamp when the battery system enters the powered-on state.

[0046] On the other hand, a battery management system is provided, which includes a processor and a memory, wherein the memory stores at least one program code, and the at least one program code is loaded and executed by the processor to implement any of the above-mentioned battery health status determination methods.

[0047] On the other hand, a computer-readable storage medium is provided, in which at least one program code is stored. The at least one program code is loaded and executed by a processor to implement any of the above-mentioned methods for determining the battery health status.

[0048] On the other hand, a computer program product is provided, wherein at least one program code is stored in the computer program product, and the at least one program code is loaded and executed by a processor to implement any of the above-mentioned methods for determining the battery health status.

[0049] An embodiment of the present application provides a method for determining the state of health of a battery. This method first determines the current inherent capacity of each battery cell in the battery system based on the current remaining charge of each battery cell and the current discharge capacity of the battery system. Then, based on the current inherent capacity and nominal capacity of each battery cell, the current state of health of the battery system is determined. As can be seen, this method uses current data when determining the state of health of the battery system. Therefore, the problem of errors gradually accumulating over time does not occur, thereby improving the accuracy of determining the state of health of the battery system.

[0050] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] FIG1 is a schematic diagram of an implementation environment of a method for determining a battery health status provided in an embodiment of the present application;

[0052] FIG2 is a flow chart of a method for determining a battery health status provided by an embodiment of the present application;

[0053] FIG3 is a schematic structural diagram of a device for determining a battery health status provided by an embodiment of the present application;

[0054] FIG4 is a structural block diagram of a battery management system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] In order to make the technical solutions and advantages of the present application clearer, the implementation methods of the present application are described in further detail below.

[0056] The terms "first," "second," "third," and "fourth," etc. in the specification and claims of this application and the accompanying drawings are used to distinguish different objects, not to describe a specific order. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements, but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0057] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, storage, display, etc.), and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the remaining power and discharge capacity involved in this application are all obtained with full authorization.

[0058] Figure 1 is a schematic diagram of an implementation environment of a battery health status determination method provided in an embodiment of the present application. Referring to Figure 1, the implementation environment includes: a battery management system (BMS) 101 and a battery system 102; the battery system includes multiple battery cells 1021; the battery management system 101 can detect the health status of the battery system 102, and manage and maintain each battery cell 1021.

[0059] The multiple battery cells 1021 included in the battery system 102 can be connected in series. Each battery cell 1021 can include one or more battery cells. If a battery cell 1021 includes multiple battery cells, these multiple battery cells can be connected in parallel. The battery cells can be lithium batteries or other types of batteries, without specific limitation.

[0060] Due to the varying spatial distribution of battery cells 1021 and the varying characteristics of battery cells 1021, the aging levels of the multiple battery cells 1021 vary. Therefore, the health states of the multiple battery cells 1021 also vary. In one possible implementation, the health state of the battery system 102 is determined by the battery cell 1021 with the worst health state. Therefore, the health state of the battery system 102 should be represented by the battery cell 1021 with the worst health state. In another possible implementation, the health state of the battery system 102 is determined by the combined effects of the multiple battery cells 1021. Therefore, the health state of the battery system 102 is represented by the combined effects of the multiple battery cells 1021.

[0061] Based on this, in one possible implementation, the battery management system 101 first determines the health status value of each battery cell 1021, then determines the minimum health status value as the current health status value of the battery system 102, and uses the health status value to reflect the health status of the battery system 102. In another possible implementation, the battery management system 101 first determines the health status value of each battery cell 1021, determines the average health status value of each battery cell 1021, and uses this average health status to reflect the health status of the battery system 102. The larger the health status value of the battery system 102, the better the health status of the battery system 102; and the smaller the health status value of the battery system 102, the worse the health status of the battery system 102.

[0062] FIG2 is a flow chart of a method for determining a battery health status provided by an embodiment of the present application, which is executed by a battery management system. Referring to FIG2 , the method includes:

[0063] Step 201: The battery management system obtains the remaining power and nominal capacity of the battery system.

[0064] The battery management system obtains the nominal capacity of the battery system. The nominal capacity refers to the discharge capacity of the battery system when it is discharged at a preset discharge rate. The preset discharge rate may be 0.2C.

[0065] The battery management system also determines the remaining power of the battery system in real time or periodically, and determines whether the battery system meets the detection conditions based on the remaining power of the battery system; if the battery system meets the detection conditions, step 202 is executed; if the battery system does not meet the detection conditions, the remaining power of the battery system continues to be detected until it is determined that the battery system meets the detection conditions based on the remaining power of the battery system.

[0066] The step of the battery management system determining whether the battery system meets the detection condition based on the remaining power of the battery system may include: the battery management system determining whether the remaining power of the battery system is within a first preset range; if the remaining power of the battery system is within the first preset range, determining whether the battery system has changed from a static state to a powered-on state, and whether the time interval between a first timestamp and a second timestamp exceeds a preset time period, where the first timestamp is the time stamp when the battery system enters the static state, and the second timestamp is the time stamp when the battery system enters the powered-on state; if the battery system has changed from a static state to a powered-on state, and the time interval between the first timestamp and the second timestamp is greater than the preset time period, the battery management system determines that the battery system meets the detection condition, and then executes step 202. If the remaining power of the battery system is not within the first preset range, the battery management system determines that the battery system does not meet the detection condition; or if the battery system has not changed from a static state to a powered-on state, or the time interval between the first timestamp and the second timestamp is less than the preset time period, the battery management system determines that the battery system does not meet the detection condition.

[0067] The "stationary state" refers to a state where the battery system is neither charging nor discharging, and the "powered state" refers to a state where the battery system is either charging or discharging. The preset duration can be set and modified as needed, for example, a preset duration of 2 hours. The first preset range can also be set and modified as needed, for example, a range of 25% to 45%.

[0068] Step 202: When it is determined that the battery system meets the detection condition based on the remaining power of the battery system, the battery management system obtains the current discharge capacity of the battery system and the voltage of each battery cell.

[0069] The current discharge capacity of the battery system is the discharge capacity of the battery system up to the present moment after the battery system is fully charged and enters the discharge state. The battery system includes a plurality of battery cells.

[0070] In an embodiment of the present application, the battery management system may pre-set a battery system full charge status flag in the data storage unit. When the battery system enters charging, whether it is AC or DC, and is fully charged, the battery management system sets the full charge status flag. When the full charge status flag is in the set state, and the battery system enters the discharge state, the battery management system obtains the current value of the battery system in real time and stores the current value of the battery system. When the battery management system determines that the battery system meets the detection conditions, the battery management system determines the discharge time of the battery system from the start of discharge to the current, obtains the stored current value of the battery system from the start of discharge to the current, integrates the current value of the battery system from the start of discharge to the current and the discharge time, and obtains the current discharge capacity of the battery system. Among them, the full charge state refers to the state of fully charging the battery system at one time, and the full charge status flag is in the set state to indicate that the battery system is fully charged at one time when charging the battery system this time.

[0071] In this step, the battery management system obtains the voltage of each battery cell through a voltage sensor.

[0072] Step 203: For each battery cell, the battery management system determines the current remaining power of the battery cell based on the voltage of the battery cell.

[0073] In this step, for each battery cell, the battery management system obtains the current temperature of the battery cell and determines the target temperature range to which the current temperature of the battery cell belongs; determines the first relationship data corresponding to the target temperature range, and the first relationship data is used to represent the linear relationship between the voltage and the remaining power of the battery cell within the target temperature range; based on the voltage of the battery cell and the first relationship data, determines the current remaining power of the battery cell.

[0074] In this implementation, the battery management system can determine the target temperature range to which the current temperature of the battery cell belongs based on the current temperature of the battery cell. Different temperature ranges correspond to different first relationship data. The battery management system determines the first relationship data corresponding to the target temperature range, and then determines the remaining power corresponding to the voltage of the battery cell based on the first relationship data, thereby obtaining the current remaining power of the battery cell.

[0075] Before step 203, the battery management system first divides the temperature into multiple intervals, for example, the multiple temperature intervals are [-20°C, -10°C], (-10°C, 0°C], (0°C, 10°C], (10°C, 20°C], (20°C, 30°C] and (30°C, 40°C], and then determines the first relationship data corresponding to each temperature interval and stores the first relationship data corresponding to each temperature interval. When executing this step, the battery management system can directly obtain the stored first relationship data corresponding to the target temperature interval.

[0076] The following is only explained by taking the first relationship data corresponding to the target temperature range as an example. The process is: the battery management system obtains a parameter table of the battery cell in the target temperature range, and based on the parameter table, determines the open circuit voltage (OCV) corresponding to the remaining power of the battery cell within the first preset range; the remaining power of the battery cell within the first preset range and its corresponding open circuit voltage are linearly fitted to obtain the first relationship data corresponding to the target temperature range.

[0077] Open circuit voltage refers to the terminal voltage of a battery system in the open circuit state. This parameter table is based on the open circuit voltage and the remaining capacity (SOC) of the battery cell. Different open circuit voltages correspond to different remaining capacities. The battery management system determines the open circuit voltage corresponding to the remaining capacity within a first preset range, and then performs a linear fit to obtain first relationship data. The first relationship data is a linear function with open circuit voltage as the independent variable and remaining capacity as the dependent variable, or remaining capacity as the independent variable and open circuit voltage as the dependent variable, without specific limitation.

[0078] The first relationship data corresponding to other temperature intervals can also be obtained in the above manner, which will not be repeated here. One point that needs to be explained is that under the condition of the same temperature interval, multiple battery cells can correspond to the same first relationship data, or multiple battery cells can correspond to different first relationship data, and there is no specific limitation on this. In the embodiment of the present application, only the example of multiple battery cells corresponding to the same first relationship data under the condition of the same temperature interval is used for explanation. Moreover, the finer the temperature interval division, the more first relationship data there are, and the more accurate the final calculated result.

[0079] Step 204: The battery management system determines the current inherent capacity of the battery cell based on the current remaining power of the battery cell and the current discharge capacity of the battery system.

[0080] The current intrinsic capacity of a battery cell is used to represent the capacity of the battery cell after it is currently fully charged.

[0081] The current remaining charge of a battery cell is the current inherent capacity of the battery cell minus the current discharge capacity after the full charge status flag is set, divided by the current inherent capacity of the battery cell. Based on this, the current inherent capacity of the battery cell can be calculated by reverse calculation from the current remaining charge of the battery cell. The process is as follows: the battery management system determines the difference between 1 and the current remaining charge of the battery cell to obtain a first difference; and determines the ratio of the current discharge capacity of the battery system to the first difference to obtain the current inherent capacity of the battery cell.

[0082] For example, SOC1 represents the current remaining capacity of the battery cell, Cap1 represents the current discharge capacity of the battery system, and Cap x Represents the current inherent capacity of the battery cell, then

[0083] Step 205: The battery management system determines the current health status value of the battery system based on the current inherent capacity and nominal capacity of each battery cell.

[0084] The current state of health (SOH) value of the battery system is used to reflect the current health state of the battery system.

[0085] The first implementation method is to characterize the health status of the battery system by the health status of the battery cell with the worst health status. In one possible implementation method, step 205 may include: the battery management system determines the ratio of the current intrinsic capacity to the nominal capacity of each battery cell to obtain the current health status value of each battery cell; determines the minimum health status value from the current health status values ​​of the multiple battery cells, and determines the minimum health status value as the current health status value of the battery system.

[0086] For example, Cap0 represents the nominal capacity of the battery system, SOH x Represents the health status value of the battery system, then

[0087] In another possible implementation, step 205 may be: the battery management system determines the minimum inherent capacity from the current inherent capacities of multiple battery cells, determines the ratio of the minimum inherent capacity to the nominal capacity, and determines the ratio as the current health status value of the battery system.

[0088] The method provided in this application first evaluates the inherent capacity or health status value of each battery cell, and uses the minimum inherent capacity or health status value to characterize the capacity of the battery system, thereby ensuring the accuracy of the available capacity of the battery system. In addition, the algorithm has a time complexity of O(n), does not involve floating-point operations or matrix operations, and is suitable for use in battery management systems. The data used in each calculation is currently acquired, and there is no secondary calculation or cumulative calculation of parameters, which controls the parameter error within a very small range. In addition, each calculation cycle is independent of each other and does not interfere with each other. Errors will not accumulate or propagate over time.

[0089] Second implementation: The health status of the battery system 102 is comprehensively represented by the health status of multiple battery cells. In one possible implementation, step 205 may include: the battery management system determines the ratio of the current intrinsic capacity to the nominal capacity of each battery cell to obtain the current health status value of each battery cell; determines the average value of the current health status value of each battery cell, and determines the average health status value as the current health status value of the battery system.

[0090] In another possible implementation, step 205 may be: the battery management system determines the average value of the current inherent capacities of the plurality of battery cells, determines the ratio of the average value of the inherent capacities to the nominal capacity, and determines the ratio as the health status value of the battery system.

[0091] In an embodiment of the present application, after the battery management system determines the health status value of the battery system, the health status value of the battery system can be displayed through the vehicle display screen, so as to facilitate the user to understand the health status of the battery system. In addition, different health status values ​​can be displayed by identification icons of different colors; accordingly, the step of the battery management system displaying the health status value of the battery system through the vehicle display screen can be: the battery management system determines the identification icon that matches the health status value, and displays the health status value and the identification icon. For example, if the health status value is 0.2, the identification icon that matches the health status value is a red icon; if the health status value is 0.5, the identification icon that matches the health status value is a yellow icon; if the health status value is 0.9, the identification icon that matches the health status value is a green icon.

[0092] An embodiment of the present application provides a method for determining the state of health of a battery. This method first determines the current inherent capacity of each battery cell in the battery system based on the current remaining charge of each battery cell and the current discharge capacity of the battery system. Then, based on the current inherent capacity and nominal capacity of each battery cell, the current state of health of the battery system is determined. As can be seen, this method uses current data when determining the state of health of the battery system. Therefore, the problem of errors gradually accumulating over time does not occur, thereby improving the accuracy of determining the state of health of the battery system.

[0093] FIG3 is a schematic diagram of a battery health status determination device according to an embodiment of the present application. Referring to FIG3 , the device includes:

[0094] A first acquisition module 301 is used to obtain the remaining power and nominal capacity of the battery system;

[0095] A second acquisition module 302 is configured to acquire, when it is determined based on the remaining power of the battery system that the battery system meets the detection condition, the current discharge capacity of the battery system and the voltage of each battery cell. The current discharge capacity of the battery system is the discharge capacity of the battery system from the time it is fully charged to the time it enters the discharge state. The battery system includes multiple battery cells.

[0096] A first determining module 303 is configured to determine, for each battery cell, the current remaining power of the battery cell based on the voltage of the battery cell;

[0097] A second determining module 304 is configured to determine a current inherent capacity of the battery cell based on the current remaining power of the battery cell and the current discharge capacity of the battery system, where the current inherent capacity of the battery cell represents the capacity of the battery cell after it is fully charged.

[0098] The third determining module 305 is used to determine the current health state value of the battery system based on the current inherent capacity and nominal capacity of each battery cell. The current health state value of the battery system is used to reflect the current health state of the battery system.

[0099] In one possible implementation, the first determination module 303 is used to obtain the current temperature of the battery cell; determine the target temperature range to which the current temperature of the battery cell belongs; determine first relationship data corresponding to the target temperature range, the first relationship data being used to represent the linear relationship between the voltage and the remaining power of the battery cell within the target temperature range; and determine the current remaining power of the battery cell based on the voltage of the battery cell and the first relationship data.

[0100] In another possible implementation, the apparatus further includes:

[0101] A third acquisition module is used to obtain a parameter table of the battery cell in a target temperature range, where the parameter table is obtained based on the open circuit voltage and the remaining power of the battery cell;

[0102] A fourth determining module is configured to determine, based on the parameter table, an open circuit voltage corresponding to a remaining capacity of the battery cell within a first preset range;

[0103] The fitting module is used to perform linear fitting on the remaining power of the battery cell within a first preset range and its corresponding open circuit voltage to obtain first relationship data corresponding to the target temperature range.

[0104] In another possible implementation, the second determination module 304 is used to determine the difference between 1 and the current remaining power of the battery cell to obtain a first difference; determine the ratio of the current discharge capacity of the battery system to the first difference to obtain the current inherent capacity of the battery cell.

[0105] In another possible implementation, the third determination module 305 is used to determine the ratio of the current inherent capacity of each battery cell to the nominal capacity to obtain the current health status value of each battery cell; determine the minimum health status value from the current health status values ​​of multiple battery cells, and determine the minimum health status value as the current health status value of the battery system.

[0106] In another possible implementation, the apparatus further includes:

[0107] The fifth determination module is used to determine that the battery system meets the detection condition when the remaining power of the battery system is within a first preset range, the battery system changes from a static state to a powered-on state, and the time interval between the first timestamp and the second timestamp is greater than a preset time length, wherein the first timestamp is the timestamp when the battery system enters the static state, and the second timestamp is the timestamp when the battery system enters the powered-on state.

[0108] An embodiment of the present application provides a device for determining the state of health of a battery. The device first determines the current inherent capacity of each battery cell in the battery system based on the current remaining charge of each battery cell and the current discharge capacity of the battery system. Then, the device determines the current state of health of the battery system based on the current inherent capacity and nominal capacity of each battery cell. Therefore, the device uses current data when determining the state of health of the battery system. Therefore, the problem of errors gradually accumulating over time does not occur, thereby improving the accuracy of determining the state of health of the battery system.

[0109] It should be noted that the battery health status determination device provided in the above embodiment only uses the division of the above-mentioned functional modules as an example to illustrate the determination of the battery health status. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the battery management system can be divided into different functional modules to complete all or part of the functions described above. In addition, the battery health status determination device provided in the above embodiment and the battery health status determination method embodiment are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0110] The structural block diagram of the battery management system can be seen in Figure 4. The battery management system 400 may vary greatly due to different configurations or performances, and may include a processor (Central Processing Units, CPU) 401 and a memory 402, wherein the memory 402 stores at least one program code, which is loaded and executed by the processor 401 to implement the above-mentioned battery health status determination method. Of course, the battery management system 400 may also have components such as a wired or wireless network interface, a keyboard, and an input and output interface for input and output. The battery management system 400 may also include other components for implementing device functions, which will not be described in detail here.

[0111] In an exemplary embodiment, a computer-readable storage medium is further provided, the computer-readable storage medium storing at least one program code, which is loaded and executed by a processor to implement the battery health status determination method in the above-mentioned embodiment. Optionally, the storage medium can be a non-transitory computer-readable storage medium, for example, a ROM (Read-Only Memory), a RAM (Random Access Memory), a CD-ROM (Compact Disc Read-Only Memory), a magnetic tape, a floppy disk, an optical data storage device, etc.

[0112] In an exemplary embodiment, a computer program product is further provided. The computer program product stores at least one program code, and the at least one program code is loaded and executed by a processor to implement the battery health status determination method in the above embodiment.

[0113] In an exemplary embodiment, the computer program product involved in the embodiments of the present application can be deployed and executed on a battery management system, or on multiple battery management systems located at one location, or on multiple battery management systems distributed at multiple locations and interconnected through a communication network. Multiple battery management systems distributed at multiple locations and interconnected through a communication network can constitute a blockchain system.

[0114] Those skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by a program to instruct the relevant hardware, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0115] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of this application and is not intended to limit this application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of this application shall be included in the scope of protection of this application.

Claims

1. A method for determining the state of health of a battery, characterized in that, The method includes: Obtaining the remaining power and nominal capacity of the battery system; When it is determined that the battery system meets the detection conditions based on the remaining power of the battery system, obtaining the current discharge capacity of the battery system and the voltage of each battery cell. The current discharge capacity of the battery system is the discharge capacity of the battery system from being fully charged and entering the discharge state until now. The battery system includes multiple battery cells; For each battery cell, determining the current remaining power of the battery cell based on the voltage of the battery cell; Based on the current remaining power of the battery cell and the current discharge capacity of the battery system, determining the current inherent capacity of the battery cell. The current inherent capacity of the battery cell is used to represent the capacity of the battery cell after being fully charged currently; Based on the current inherent capacity of each battery cell and the nominal capacity, determining the current state-of-health value of the battery system. The current state-of-health value of the battery system is used to reflect the current health state of the battery system.

2. The method according to claim 1, characterized in that, The determining the current remaining power of the battery cell based on the voltage of the battery cell includes: Obtaining the current temperature of the battery cell; Determining the target temperature range to which the current temperature of the battery cell belongs; Determining the first relationship data corresponding to the target temperature range. The first relationship data is used to represent the linear relationship between the voltage and the remaining power of the battery cell within the target temperature range; Based on the voltage of the battery cell and the first relationship data, determining the current remaining power of the battery cell.

3. The method according to claim 2, wherein The determining the first relationship data corresponding to the target temperature range includes: Obtaining the parameter table of the battery cell within the target temperature range. The parameter table is obtained based on the open-circuit voltage and the remaining power of the battery cell; Based on the parameter table, determining the open-circuit voltage corresponding to the remaining power of the battery cell within the first preset range; Performing linear fitting on the remaining power of the battery cell within the first preset range and its corresponding open-circuit voltage to obtain the first relationship data corresponding to the target temperature range.

4. The method according to claim 1, characterized in that, The determining the current inherent capacity of the battery cell based on the current remaining power of the battery cell and the current discharge capacity of the battery system includes: Determining the difference between 1 and the current remaining power of the battery cell to obtain the first difference; Determining the ratio of the current discharge capacity of the battery system to the first difference to obtain the current inherent capacity of the battery cell.

5. The method according to claim 1, characterized in that, The determining the current state-of-health value of the battery system based on the current inherent capacity of each battery cell and the nominal capacity includes: Determining the ratio of the current inherent capacity of each battery cell to the nominal capacity to obtain the current state-of-health value of each battery cell; Determining the minimum state-of-health value from the current state-of-health values of the multiple battery cells, and determining the minimum state-of-health value as the current state-of-health value of the battery system.

6. The method according to claim 1, wherein The method further includes: When the remaining power of the battery system is within a first preset range, and the battery system changes from a stationary state to a powered-on state, and the time interval between the first timestamp and the second timestamp is greater than a preset duration, it is determined that the battery system meets the detection conditions. The first timestamp is the timestamp when the battery system enters the stationary state, and the second timestamp is the timestamp when the battery system enters the powered-on state.

7. A device for determining the state of health of a battery, characterized in that, The device includes: A first acquisition module for acquiring the remaining power and nominal capacity of the battery system; A second acquisition module for acquiring the current discharge capacity of the battery system and the voltage of each battery cell when it is determined that the battery system meets the detection conditions based on the remaining power of the battery system. The current discharge capacity of the battery system is the discharge capacity of the battery system after being fully charged and entering the discharge state up to the present. The battery system includes a plurality of battery cells; A first determination module for determining, for each battery cell, the current remaining power of the battery cell based on the voltage of the battery cell; A second determination module for determining the current inherent capacity of the battery cell based on the current remaining power of the battery cell and the current discharge capacity of the battery system. The current inherent capacity of the battery cell is used to represent the capacity of the battery cell after being fully charged currently; A third determination module for determining the current health state value of the battery system based on the current inherent capacity of each battery cell and the nominal capacity. The current health state value of the battery system is used to reflect the current health state of the battery system. The first determination module is configured to obtain the current temperature of the battery cell; determine the target temperature range to which the current temperature of the battery cell belongs; determine the first relationship data corresponding to the target temperature range, where the first relationship data is used to represent the linear relationship between the voltage and the remaining power of the battery cell within the target temperature range; and determine the current remaining power of the battery cell based on the voltage of the battery cell and the first relationship data.

8. The device according to claim 7, wherein The device further includes:

9. The device according to claim 8, characterized in that, A third acquisition module for acquiring the parameter table of the battery cell within the target temperature range, where the parameter table is obtained based on the open-circuit voltage and the remaining power of the battery cell; A fourth determination module for determining the open-circuit voltage corresponding to the remaining power of the battery cell within a first preset range based on the parameter table; A fitting module for performing linear fitting on the remaining power of the battery cell within the first preset range and its corresponding open-circuit voltage to obtain the first relationship data corresponding to the target temperature range. The second determination module is configured to determine the difference between 1 and the current remaining power of the battery cell to obtain a first difference; and determine the ratio of the current discharge capacity of the battery system to the first difference to obtain the current inherent capacity of the battery cell.

10. The device according to claim 7, characterized in that, ​ 11. The device according to claim 7, characterized in that, The third determination module is configured to determine the ratio of the current inherent capacity of each battery cell to the nominal capacity, so as to obtain the current state of health value of each battery cell; determine the minimum state of health value from the current state of health values of the multiple battery cells, and determine the minimum state of health value as the current state of health value of the battery system.

12. The device according to claim 7, wherein The device further includes: A fifth determination module, configured to determine that the battery system meets the detection condition when the remaining power of the battery system is within a first preset range, and the battery system changes from a stationary state to a powered-on state, and the time interval between a first timestamp and a second timestamp is greater than a preset duration, where the first timestamp is the timestamp when the battery system enters the stationary state, and the second timestamp is the timestamp when the battery system enters the powered-on state.

13. A battery management system, characterized in that, The battery management system includes a processor and a memory, and at least one program code is stored in the memory and is loaded and executed by the processor to implement the battery state of health determination method according to any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that, At least one program code is stored in the computer-readable storage medium and is loaded and executed by a processor to implement the battery state of health determination method according to any one of claims 1 to 6.

15. A computer program product, characterized in that, At least one program code is stored in the computer program product and is loaded and executed by a processor to implement the battery state of health determination method according to any one of claims 1 to 6.

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