Battery cell charging control method, type determination method, system, device, and medium

Abstract

The present disclosure belongs to the technical field of electrochemistry, and discloses a battery cell charging control method, a type determination method, a system, a device and a medium. The battery cell charging control method comprises: determining a target charging rate of a battery cell to be measured according to the type of the battery cell to be measured, a preset swelling force of the battery cell, and a charging swelling force corresponding to a charging rate model of the battery cell in a charging process; wherein the preset swelling force of the battery cell is a recommended swelling force threshold of the battery cell; and controlling the battery cell to be measured to be charged at a charging rate not exceeding the target charging rate. The battery cell charging control method can predict the target charging rate of the battery cell to be measured, and control the battery cell to be measured to be charged at a charging rate not exceeding the target charging rate in a subsequent charging process, thereby preventing the battery cell from swelling excessively and improving the performance and safety of the battery cell.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology, specifically relating to a battery cell charging control method, type determination method, system, equipment, and medium. Background Technology

[0002] With the emergence of consumer electronics such as mobile phones, tablets, and electric vehicles, lithium-ion batteries have continuously gained market share due to their long lifespan and high energy density. However, with the continuous upgrading of 3C digital products and the rapid development of electric vehicles, people have higher demands for the fast charging performance of lithium-ion batteries. But fast charging can lead to safety issues, especially when charging at high rates, the battery will expand significantly in volume. This causes the batteries in the battery module to be subjected to greater expansion forces, which directly affects the performance and safety of the cells, battery modules, and the entire battery pack. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a battery cell charging control method, type determination method, system, device and medium.

[0004] A first aspect of the present invention provides a method for controlling the charging rate of a battery cell, comprising:

[0005] Based on the type of the battery cell under test, the preset expansion force of the battery cell, and the charging expansion force and charging rate model of the battery cell during the charging process, the target charging rate of the battery cell under test is determined; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell.

[0006] The battery cell under test is controlled to be charged at a charging rate not exceeding the target charging rate.

[0007] Preferably, determining the target charging rate of the battery cell under test based on the type of the battery cell, the preset expansion force of the battery cell, and the charging expansion force and charging rate model corresponding to the battery cell during charging includes:

[0008] Based on the type of the battery cell under test, determine the charging expansion force and charging rate model corresponding to the battery cell of the same type as the battery cell under test;

[0009] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model of the same type of battery cell to obtain the target charging rate of the battery cell under test.

[0010] Preferably, under preset operating conditions, a model of the charging expansion force and charging rate of the battery cell during the charging process is pre-established.

[0011] Further preferably, a charging expansion force and charging rate model corresponding to different types of battery cells during the charging process is established in advance.

[0012] Preferably, controlling the battery cell under test to be charged at a charging rate not exceeding the target charging rate includes:

[0013] Based on the current operating condition of the battery cell under test, the target charging rate of the battery cell under test is adjusted in real time, and the battery cell under test is controlled to be charged at a charging rate that does not exceed the real-time adjusted target charging rate.

[0014] Preferably, the preset operating conditions include a preset temperature.

[0015] More preferably, the step of pre-establishing a model of the charging expansion force and charging rate of the battery cell during the charging process under preset operating conditions includes:

[0016] Under preset operating conditions, the charging rate corresponding to different states of charge of the battery cell during the charging process is obtained, and a model of the relationship between the charging rate and the state of charge of the battery cell is established.

[0017] Under the preset working conditions, the charging expansion force of the battery cell under different states of charge during the charging process is obtained, and a model of the relationship between the charging expansion force and the state of charge of the battery cell is established.

[0018] Based on the relationship model between the charging rate and the state of charge of the battery cell and the relationship model between the charging expansion force and the state of charge of the battery cell, a model of the charging expansion force and the charging rate of the battery cell is established.

[0019] Preferably, under preset operating conditions, the charging rate corresponding to different states of charge of the battery cell during charging is obtained, and a model of the relationship between the charging rate and the state of charge of the battery cell is established:

[0020] Data fitting is performed on the charging rate corresponding to different states of charge of the battery cell during the charging process to establish a first functional relationship expression with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0021] Preferably, obtaining the charging rate corresponding to different states of charge of the battery cell during charging includes:

[0022] First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage is obtained after the preset charging time. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

[0023] Preferably, under the preset operating conditions, acquiring the charging expansion force corresponding to different states of charge of the battery cell during charging, and establishing a model of the relationship between the charging expansion force and the state of charge of the battery cell, includes:

[0024] Data fitting is performed on the charging expansion force corresponding to different states of charge of the battery cell during the charging process to establish a second functional relationship expression with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0025] Preferably, an in-situ expansion tester is used to obtain the charging expansion force of the battery cell under different charging states during the charging process.

[0026] Preferably, the in-situ expansion tester includes:

[0027] Clamps are used to hold battery cells;

[0028] The charging module is used to perform charging tests on the battery cell under different states of charge when the battery cell is in a clamped state, and to record the corresponding charging parameters of the battery cell during the charging process; the charging parameters include current, voltage and time.

[0029] A pressure sensor is used to obtain the expansion force value of the battery cell during the charging process;

[0030] The data processing module is used to process the cell expansion force value obtained by the pressure sensor and the charging parameters recorded by the charging module to obtain the charging expansion force corresponding to different charging states of the cell during the charging process.

[0031] Preferably, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0032] Preferably, the first functional relational expression is:

[0033]

[0034] Among them, Y 倍率 X represents the cell charging rate. SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0035] Preferably, the second functional relational expression is:

[0036]

[0037] Among them, F 膨胀力 X represents the cell's charging expansion force. SOCThe state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0038] Preferably, the charging expansion force and charging rate model is as follows:

[0039]

[0040] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0041] A second aspect of the present invention provides a system for determining the charging rate of a battery cell, comprising:

[0042] The model storage module is used to pre-store the charging expansion force and charging rate model of the battery cell during the charging process;

[0043] The target charging rate determination module is used to determine the target charging rate of the battery cell under test based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to the battery cell during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell;

[0044] The control module is used to control the battery cell under test to be charged at a charging rate not exceeding the target charging rate.

[0045] A third aspect of the present invention provides a method for determining the type of battery cell, comprising:

[0046] Based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, the target charging rate of different types of battery cells is determined; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell.

[0047] Determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test based on the target charging rate of the different types of cells.

[0048] Preferably, determining the maximum charging rate corresponding to the cell under test under the preset expansion force, and then determining the type of the cell under test based on the target charging rate of the different types of cells, includes:

[0049] The maximum charging rate of the cell under test is calculated by subtracting the target charging rate of the different types of cells, and the cell type with the smallest difference is selected as the type of the cell under test.

[0050] Preferably, determining the target charging rate for different types of battery cells based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process includes:

[0051] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, and the target charging rate of different types of battery cells is obtained.

[0052] Preferably, under preset operating conditions, a charging expansion force and charging rate model corresponding to the different types of battery cells during the charging process is pre-established.

[0053] Preferably, the preset operating conditions include a preset temperature.

[0054] Preferably, the step of pre-establishing charging expansion force and charging rate models for different types of battery cells during the charging process under preset operating conditions includes:

[0055] Under preset operating conditions, the charging rate corresponding to different states of charge of each type of battery cell during the charging process is obtained, and a model of the relationship between the charging rate and the state of charge of each type of battery cell is established.

[0056] Under the preset working conditions, the charging expansion force corresponding to different states of charge of each type of battery cell during the charging process is obtained, and a model of the relationship between the charging expansion force and the state of charge of each type of battery cell is established.

[0057] Based on the relationship model between charging rate and state of charge for any type of battery cell, and the relationship model between charging expansion force and state of charge for the corresponding type of battery cell, establish a model of charging expansion force and charging rate for that type of battery cell.

[0058] Preferably, under preset operating conditions, the charging rate corresponding to different states of charge for each type of battery cell during charging is obtained, and a model relating the charging rate to the state of charge for each type of battery cell is established.

[0059] Data fitting is performed on the charging rate corresponding to different states of charge during the charging process for each type of battery cell, and a first functional relationship expression is established with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0060] Preferably, obtaining the charging rate corresponding to different states of charge for each type of battery cell during charging includes:

[0061] First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage is obtained after the preset charging time. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

[0062] Preferably, under the preset operating conditions, obtaining the charging expansion force corresponding to different states of charge for each type of battery cell during charging, and establishing a model of the relationship between the charging expansion force and the state of charge for each type of battery cell, includes:

[0063] Data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. A second functional relationship expression is established with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0064] Preferably, an in-situ expansion tester is used to obtain the charging expansion force corresponding to different charging states of each type of battery cell during the charging process.

[0065] Preferably, the in-situ expansion tester includes:

[0066] Clamps are used to hold battery cells;

[0067] The charging module is used to perform charging tests on the battery cell under different states of charge when the battery cell is in a clamped state, and to record the corresponding charging parameters of the battery cell during the charging process; the charging parameters include current, voltage and time.

[0068] A pressure sensor is used to obtain the expansion force value of the battery cell during the charging process;

[0069] The data processing module is used to process the cell expansion force value obtained by the pressure sensor and the charging parameters recorded by the charging module to obtain the charging expansion force corresponding to different charging states of the cell during the charging process.

[0070] Preferably, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0071] Preferably, the first functional relational expression is:

[0072]

[0073] Among them, Y 倍率 X represents the cell charging rate.SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0074] Preferably, the second functional relational expression is:

[0075]

[0076] Among them, F 膨胀力 X represents the cell's charging expansion force. SOC The state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0077] Preferably, the charging expansion force and charging rate model is as follows:

[0078]

[0079] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0080] A fourth aspect of the present invention provides a system for determining the type of battery cell, comprising:

[0081] The model storage module is used to pre-store the charging expansion force and charging rate models corresponding to different types of battery cells during the charging process;

[0082] The target charging rate determination module determines the target charging rate for different types of battery cells based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell;

[0083] The cell type determination module is used to determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test according to the target charging rate of the different types of cells.

[0084] A fifth aspect of the present invention provides an electronic device comprising:

[0085] One or more processors;

[0086] Memory, used to store one or more programs.

[0087] When one or more programs are executed by one or more processors, the one or more processors perform the steps of the cell charging rate control method provided in the embodiments of this application, or perform the steps of the cell type determination method provided in the embodiments of this application.

[0088] A sixth aspect of the present invention provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of a cell charging rate control method as provided in the embodiments of the present application, or implements the steps of a cell type determination method as provided in the embodiments of the present application.

[0089] According to the battery cell charging control method, type determination method, system, device and medium provided by the present invention, the battery cell charging control method can predict the target charging rate of the battery cell under test by using the charging expansion force and charging rate model corresponding to the battery cell during the charging process, and control the battery cell under test to be charged at a charging rate not exceeding the target charging rate in the subsequent charging process, so as to prevent the battery cell from over-expanding and improve the performance and safety of the battery cell, battery module and the entire battery pack. Attached Figure Description

[0090] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0091] Figure 1 An exemplary flowchart of a cell charging rate control method provided in this application embodiment;

[0092] Figure 2 An exemplary flowchart of step S100 provided in an embodiment of this application;

[0093] Figure 3 This is an exemplary structural diagram of the in-situ expansion tester provided in the embodiments of this application;

[0094] Figure 4 Test diagram of the charging rate and state of charge relationship model provided in the embodiments of this application;

[0095] Figure 5 A side view of the model relating charging expansion force and state of charge provided in an embodiment of this application;

[0096] Figure 6 An exemplary structural diagram of a control system for the battery cell charging rate provided in an embodiment of this application;

[0097] Figure 7 An exemplary structural diagram of the model storage module provided in the embodiments of this application;

[0098] Figure 8An exemplary flowchart of a method for determining the cell type provided in an embodiment of this application;

[0099] Figure 9 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application.

[0100] above Figure 3 In the middle: 10 In-situ expansion tester; 11 Fixture; 111 First pressure plate; 112 Second pressure plate; 12 Charging module; 121 Parameter acquisition unit; 13 Pressure sensor; 14 Data processing module; 15 Battery cell; 151 Positive electrode tab; 152 Negative electrode tab. Detailed Implementation

[0101] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0102] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0103] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0104] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0105] In the description of this specification, the terms "one embodiment," "some embodiments," "exemplary embodiment," "example," "specific example," or "some examples," etc., are intended to indicate that a particular feature, structure, material, or characteristic associated with that embodiment or example is included in at least one embodiment or example of this disclosure. The illustrative representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics mentioned may be included in any suitable manner in any one or more embodiments or examples.

[0106] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this disclosure, unless otherwise stated, "a plurality of" means two or more.

[0107] The technical terms used in this application are defined as follows:

[0108] Charging rate: refers to the current required to charge a battery to its rated capacity within a specified time. It is equal to a multiple of the battery's rated capacity and is usually represented by the letter C. The magnitude of the charging current is generally expressed as the charging rate, i.e.: Charging rate = Charging current / Rated capacity; for example, a battery with a rated capacity of 100mAh charging at 20mA has a charging rate of 0.2C.

[0109] SOC (State of Charge): Also known as the remaining capacity, it represents the ratio of the remaining capacity of a battery after a period of use or long-term storage to its capacity when fully charged (battery capacity). It is usually expressed as a percentage, and its value ranges from 0 to 1. When SOC = 0, it means that the battery is fully discharged, and when SOC = 1, it means that the battery is fully charged.

[0110] The volume change of a battery during charging is mainly related to the behavior of lithium ion insertion and extraction. Especially under high-rate charging conditions, lithium ions move faster from the positive electrode to the negative electrode or vice versa, resulting in uneven distribution of lithium ions along the thickness direction and variations in the battery's expansion force. When a battery is directly charged under high-rate conditions, it will experience significant volume expansion, causing the cells and modules within the battery module to be subjected to substantial expansion forces. This directly affects the performance and safety of the cells, battery module, and the entire battery pack.

[0111] To solve the above problems, refer to Figure 1 A first aspect of this application provides a method for controlling the charging rate of a battery cell, comprising:

[0112] S120: Determine the target charging rate of the battery cell under test based on the type of the battery cell, the preset expansion force of the battery cell, and the charging expansion force and charging rate model of the battery cell during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell.

[0113] S130: Control the battery cell under test to be charged at a charging rate not exceeding the target charging rate.

[0114] Specifically, based on the type of the cell under test, the industry-standard recommended expansion force threshold for cells, and the charging expansion force and charging rate model of the cell during charging, the target charging rate of the cell under test is determined. This target charging rate is the upper limit of the charging rate of the corresponding cell under test. This allows the cell under test to be charged at a rate not exceeding the target charging rate during subsequent charging processes, preventing excessive cell expansion and improving the performance and safety of the cell, battery module, and the entire battery pack.

[0115] The preset expansion force of the battery cell under test is a recommended expansion force threshold. This recommended expansion force threshold is the upper limit of the allowable expansion force of the battery cell during charging. If the expansion force of the battery cell exceeds the upper limit during charging, the battery cell will be damaged. In this application, the battery cell under test is charged at a charging rate less than or equal to the target charging rate during subsequent charging. This meets the high-rate charging requirements of the battery cell without causing excessive expansion, thus improving the safety of the battery cell. For example, the currently recommended expansion force threshold for battery cells in the industry is 0.02 MPa. Different battery cell sizes have different thresholds, and the expansion force threshold can be converted to 50 N or 61 N based on commonly used battery cell sizes.

[0116] In some implementations, reference Figure 1 Before step S120, the following are also included:

[0117] S110: Pre-establish a model of the charging expansion force and charging rate of the battery cell during the charging process.

[0118] Specifically, charging tests are conducted on the battery cells, and a model of the charging expansion force and charging rate of the battery cells is established in advance. This facilitates the prediction of the target charging rate of the battery cells under test based on the pre-established model of the charging expansion force and charging rate of the battery cells.

[0119] In some implementations, in step S110, a charging expansion force and charging rate model corresponding to different types of battery cells during the charging process is established in advance.

[0120] Specifically, different types of battery cells refer to cells with at least one difference in model or material. The difference in material refers to the different materials used for the positive and / or negative electrode plates. When predicting the target charging rate of a battery cell under test, a matching charging expansion force and charging rate model can be selected from the charging expansion force and charging rate models corresponding to different types of cells during charging. Then, the target charging rate of the battery cell under test can be predicted based on the selected model, thus improving prediction accuracy.

[0121] In some implementations, in S110, under preset operating conditions, a model of the charging expansion force and charging rate of the battery cell during the charging process is pre-established.

[0122] Specifically, for each type of battery cell, a charging expansion force and charging rate model is pre-established under each preset working condition. Each type of battery cell corresponds to a different charging expansion force and charging rate model under different preset working conditions, thereby obtaining the charging expansion force and charging rate models corresponding to different types of battery cells under different preset working conditions.

[0123] In some implementations, in S110, the preset operating condition includes a preset temperature.

[0124] Specifically, the preset temperature includes any temperature value within the range of -20℃ to 45℃. For example, the preset temperature is -20℃ to -10℃ in winter and 25℃ to 45℃ in summer. Examples include preset temperatures of -15℃, -17℃, -20℃, 20℃, 24℃, 25℃, 27℃, 30℃, 35℃, 40℃, and 45℃. The charging expansion force and charging rate model corresponding to the battery cell at different preset temperatures can be obtained. The charging performance of the battery cell will vary under different ambient temperatures. Based on the actual ambient temperature of the battery cell under test, the corresponding charging expansion force and charging rate model at the preset temperature can be selected to predict its charging rate, resulting in a more accurate prediction of the target charging rate for the battery cell under test.

[0125] In some implementations, reference Figure 2 S110 specifically includes:

[0126] S111: Under preset operating conditions, obtain the charging rate corresponding to different states of charge of the battery cell during the charging process, and establish a model of the relationship between the charging rate and the state of charge of the battery cell.

[0127] Specifically, each type of battery cell is charged at a preset temperature, and the charging rate of each type of battery cell at different SOC states is tested. The relationship model between the charging rate and the state of charge of each type of battery cell at each preset temperature is obtained. The different SOC states are distributed in an arithmetic sequence or a non-arithmetic sequence, such as different SOC states of 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%.

[0128] Among them, obtaining the charging rate corresponding to different states of charge of the battery cell during charging includes:

[0129] First, the battery cell is adjusted to a specific state of charge using a preset pulse rate. Then, in this state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage reached after the preset charging time is obtained. This maximum charging rate is taken as the charging rate of the battery cell in that state of charge. The preset pulse rate is 0.3C-1C, preferably 1C; the preset time is 20-40s, preferably 30s.

[0130] It is understood that the charging rates corresponding to different states of charge during the charging process of the above-mentioned battery cells are for the same type of battery cells. The method and principle for obtaining the charging rates corresponding to different states of charge during the charging process of different types of battery cells are the same, and this application will not elaborate further.

[0131] For example, if a certain type of battery cell is adjusted to the corresponding SOC state (40%) using 1C, and then charged with constant current at different rates for 30 seconds in this SOC state, the maximum charging rate at which the voltage reaches the upper limit voltage after 30 seconds of charging is obtained, and this maximum charging rate is taken as the charging rate corresponding to this 40% SOC state.

[0132] S112: Under the preset working conditions, obtain the charging expansion force of the battery cell under different states of charge during the charging process, and establish a model of the relationship between the charging expansion force and the state of charge of the battery cell.

[0133] Specifically, each type of battery cell is charged at a preset temperature, and the charging expansion force of each type of battery cell at different SOC states is tested to obtain a model of the relationship between the charging expansion force and the state of charge for each type of battery cell at each preset temperature. The different SOC states are between 0 and 1, distributed in an arithmetic or non-arithmetic sequence, such as different SOC states of 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 100%.

[0134] Among them, such as Figure 3 As shown, the in-situ expansion tester 10 is used to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process, which is inexpensive.

[0135] The in-situ expansion tester 10 includes:

[0136] Clamp 11 is used to clamp battery cell 15;

[0137] The charging module 12 is used to perform charging tests on the battery cell 15 under different states of charge when the battery cell 15 is in a clamped state, and to record the charging parameters of the battery cell 15 during the charging process; the charging parameters include current, voltage and time.

[0138] Pressure sensor 13 is used to obtain the expansion force value of battery cell 15 during charging;

[0139] The data processing module 14 is used to process the expansion force value of the battery cell 15 obtained by the pressure sensor 13 and the charging parameters recorded by the charging module 12 to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0140] Specifically, the in-situ expansion tester includes a fixture 11, a charging module 12, a pressure sensor 13, and a data processing module 14. The fixture 11 includes a first pressure plate 111 and a second pressure plate 112. A fixed gap is preset between the first pressure plate 111 and the second pressure plate 112. This fixed gap is slightly larger than the thickness of the battery cell 15. The fixed gap is used to place the battery cell 15 so that the fixture 11 can hold the battery cell 15.

[0141] A pressure sensor 13 is disposed on one side of the first pressure plate 111 or the second pressure plate 112 that is close to each other. The pressure sensor 13 is used to acquire the expansion force value of the battery cell 15 in real time during the charging process. As the state of charge of the battery cell 15 changes during the charging process, the thickness of the battery cell 15 also changes, but the gap between the first pressure plate 111 and the second pressure plate 112 remains unchanged. The pressure sensor 13 can collect the pressure on the battery cell 15 in real time during the charging process.

[0142] The positive tab 151 and negative tab 152 of the battery cell 15 are connected to the charging module 12. The charging module 12 performs charging tests on the battery cell 15 and records charging parameters in real time, including current, voltage, and time. Parameter acquisition devices, such as voltage and / or current acquisition devices, are also connected to the positive tab 151 and negative tab 152 of the battery cell to obtain voltage and current values.

[0143] The data processing module 14 is used to process the expansion force value of the battery cell 15 obtained by the pressure sensor 13 and the charging parameters recorded by the charging module 12 to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0144] For example, the battery cell 15 in its initial state of charge (such as a zero-state battery cell) is fixed in a preset fixed gap between the first pressure plate 111 and the second pressure plate 112 of the clamp 11. The initial expansion force of the battery cell 15 is 0. The charging module 12 uses a preset current, such as 1C, to charge the zero-state battery cell 15 under different states of charge (such as 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%) until the battery cell is fully charged. The charging parameters of the battery cell 15 during the charging process are recorded, such as charging time, charging current, and charging voltage.

[0145] The data processing module 14 can obtain the current charge level of the battery cell 15 based on the charging parameters acquired by the charging module 12. For example, the current charge level is the product of the constant charging current and the charging time. The data processing module 14 can also calculate the real-time charge level of the battery cell 15 based on the real-time expansion force value of the battery cell 15 acquired by the pressure sensor 13 and the charging parameters acquired by the charging module 12, thus obtaining the data on the change of the expansion force of the battery cell 15 with its state of charge.

[0146] S113: Based on the relationship model between the charging rate and the state of charge of the battery cell and the relationship model between the charging expansion force and the state of charge of the battery cell, establish a model of the charging expansion force and the charging rate of the battery cell.

[0147] Specifically, the relationship between the charging rate and the state of charge of the battery cell at the same preset temperature is correlated with the relationship between the charging expansion force and the state of charge, so as to obtain the charging expansion force and charging rate model of the battery cell at the same preset temperature.

[0148] It is understood that the charging rates corresponding to different states of charge during the charging process of the aforementioned battery cells refer to the same type of battery cell. The method for obtaining the charging rates corresponding to different states of charge for different types of battery cells during the charging process is based on the same principle, and will not be elaborated upon in this application. This allows for the acquisition of charging expansion force and charging rate models for different types of battery cells at different preset temperatures. This application obtains the charging expansion force and charging rate models for each type of battery cell at each preset temperature in a simple and easy manner, and the entire testing process does not require destructive treatment of the battery cells, thus improving the safety of battery cell testing.

[0149] It should be noted that the specific type of the battery cell under test in this application embodiment is not particularly limited, and those skilled in the art can set it according to actual needs. For example, if the battery cell under test is a lithium-ion battery cell, the lithium-ion battery includes a pouch lithium-ion battery or a prismatic lithium-ion battery, preferably a pouch lithium-ion battery.

[0150] In some implementations, S111 specifically includes:

[0151] Data fitting is performed on the charging rate corresponding to different states of charge of the battery cell during the charging process to establish a first functional relationship expression with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0152] Specifically, at each preset temperature, data fitting is performed on the charging rate corresponding to different states of charge for each type of battery cell during the charging process. For example, the state of charge is used as the independent variable and the charging rate is used as the dependent variable; or, the charging rate is used as the independent variable and the state of charge is used as the dependent variable. A series of scatter plots are plotted, and curve or straight line fitting is used to fit the scatter plots to obtain the first functional relationship expression. The first functional relationship expression is used as the model of the relationship between the charging rate and the state of charge of this type of battery cell at the preset temperature.

[0153] In some implementations, S112 specifically includes:

[0154] Data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. A second functional relationship expression is established with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0155] Specifically, at each preset temperature, data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. For example, the state of charge is used as the independent variable and the charging expansion force is used as the dependent variable; or, the charging expansion force is used as the independent variable and the state of charge is used as the dependent variable. A series of scatter plots are plotted, and curve or straight line fitting is used to fit the scatter plots to obtain a second functional relationship expression. The second functional relationship expression is used as the model of the relationship between the charging expansion force and the state of charge of this type of battery cell at the preset temperature.

[0156] In some implementations, in S111 and S112, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0157] Specifically, this application can select linear regression or multinomial regression methods to fit data on the charging rate corresponding to different states of charge during charging for each type of battery cell in step S111, and to fit data on the charging expansion force corresponding to different states of charge during charging for each type of battery cell in step S112, using linear regression or multinomial regression methods for data fitting, requiring a regression determination coefficient R. 2 At least greater than 90%, preferably greater than 95%, more preferably greater than 99%. Wherein, the coefficient of determination R... 2 Ri reflects the proportion of the total variation of the dependent variable that can be explained by the independent variables through the regression relationship. 2 The closer a value is to 1, the better the independent variable explains the dependent variable in the regression analysis.

[0158] In some implementations, in S111, the first functional relational expression is:

[0159]

[0160] Among them, Y 倍率 X represents the cell charging rate. SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0161] Specifically, multinomial regression analysis is used to fit the charging rate corresponding to different states of charge during charging for each type of battery cell in step S111. A first functional relationship expression is established with state of charge as the independent variable and charging expansion force as the dependent variable. Through data fitting, the degree N of the highest term, coefficients A1 and B1, and the constant term C1 in the first functional relationship expression can be determined. This allows for the determination of the relationship between the charging rate and state of charge for each type of battery cell at each preset temperature. When N is 1, the first functional relationship expression is a linear regression model; when N is greater than 1, the first functional relationship expression is a multinomial regression model.

[0162] In some implementations, in S112, the second functional relational expression is:

[0163]

[0164] Among them, F 膨胀力 X represents the cell's charging expansion force. SOC The state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0165] Specifically, multinomial regression analysis is used to fit the charging expansion force corresponding to different states of charge during charging for each type of battery cell in step S111. A second functional relationship expression is established with state of charge as the independent variable and charging expansion force as the dependent variable. Through data fitting, the degree n of the highest term, coefficients A2 and B2, and the constant term C2 in the second functional relationship expression can be determined. This allows for the determination of the relationship between charging expansion force and state of charge for each type of battery cell at each preset temperature. Specifically, when n is 1, the second functional relationship expression is a linear regression model; when n is greater than 1, the second functional relationship expression is a multinomial regression model.

[0166] In some implementations, in S113, the charging expansion force and charging rate model is as follows:

[0167]

[0168] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0169] Specifically, by eliminating the same variable, State of Charge (SOC), from the first and second functional relationships, a charging expansion force and charging rate model for each type of cell at each preset temperature is obtained.

[0170] By changing the preset temperature and repeating steps S111 to S113, the charging expansion force and charging rate models corresponding to each type of battery cell at different preset temperatures can be obtained. Similarly, by changing the battery cell type and repeating steps S111 to S113, the charging expansion force and charging rate models corresponding to different types of battery cells at each preset temperature can be obtained.

[0171] By establishing a model of charging expansion force and charging rate, researchers can understand the relationship between cell expansion force and charging rate under different charging strategies. This allows for a more accurate understanding of the actual working state of the cell under test and a more efficient study of the changes in cell expansion force under different charging strategies, thus enabling the selection of a better charging strategy. For example, based on the type of cell under test, the industry-standard recommended expansion force threshold for cells, and the charging expansion force and charging rate model corresponding to different types of cells during charging, a target charging rate for the cell under test under preset operating conditions can be determined. This target charging rate is the upper limit of the charging rate for the corresponding cell under test, controlling the cell under test to be charged at a rate not exceeding the target charging rate during subsequent charging processes. This prevents excessive cell expansion and improves the performance and safety of the cell, battery module, and the entire battery pack.

[0172] In some implementations, S120 specifically includes:

[0173] Based on the type of the battery cell under test, determine the charging expansion force and charging rate model corresponding to the battery cell of the same type as the battery cell under test;

[0174] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model of the matched battery cell of the same type to obtain the target charging rate of the battery cell under test.

[0175] Specifically, pre-established models of charging expansion force and charging rate for different types of battery cells during charging are stored in a database. The database records the charging expansion force and charging rate models for each type of battery cell under each preset operating condition; that is, the battery cell type, preset operating condition, and charging expansion force and charging rate model are stored in a one-to-one correspondence with the database. The type of the battery cell under test is matched with different battery cell types in the database. A charging expansion force and charging rate model corresponding to a specific battery cell type that matches the type under test is selected from the database. The industry-standard recommended expansion force threshold for battery cells is input into the matched charging expansion force and charging rate model for that specific battery cell type to obtain the target charging rate for the battery cell under test under the preset operating conditions. This allows for understanding the upper limit of the charging rate (target charging rate) of the battery cell under test during charging, preventing excessive expansion of the battery cell under test.

[0176] In some implementations, S130 specifically includes:

[0177] Based on the current operating condition of the battery cell under test, the target charging rate of the battery cell under test is adjusted in real time, and the battery cell under test is controlled to be charged at a charging rate not exceeding the real-time adjusted target charging rate.

[0178] Specifically, the current operating conditions of the battery cell under test are compared with different preset operating conditions in the database to determine the charging expansion force and charging rate model corresponding to the current operating conditions of the battery cell under test. The recommended expansion force threshold of the battery cell is input into the determined charging expansion force and charging rate model to obtain the real-time target charging rate of the battery cell under test under the current operating conditions. The battery cell under test is then controlled to charge at a charging rate less than or equal to the real-time target charging rate. In this example, by combining the current operating conditions of the battery cell under test, the charging rate of the battery cell under test can be controlled in real time, improving the control accuracy of the battery cell and preventing excessive expansion of the battery cell.

[0179] For example, if the current temperature of the battery cell under test is 30℃, the charging expansion force and charging rate model corresponding to 30℃ is selected from the database. The recommended expansion force threshold of the battery cell is input into the charging expansion force and charging rate model corresponding to 30℃, resulting in a target charging rate A for the battery cell under test at 30℃. Then, the battery cell under test is controlled to be charged at a charging rate B, where B≤A. If the temperature of the battery cell rises to 40℃ during operation, the charging expansion force and charging rate model corresponding to 40℃ is selected from the database. The recommended expansion force threshold of the battery cell is input into the charging expansion force and charging rate model corresponding to 40℃, resulting in a target charging rate C for the battery cell under test at 40℃. Then, the battery cell under test is controlled to be charged at a charging rate D, where D≤C. Therefore, the battery cell under test switches from charging rate B to charging rate D according to the change in temperature, improving the control accuracy of the battery cell charging rate and avoiding excessive expansion of the battery cell.

[0180] The present invention will now be described with reference to specific embodiments. It should be noted that these embodiments are merely descriptive and do not limit the present invention in any way.

[0181] Example 1

[0182] Taking a 5Ah soft-pack ternary lithium-ion battery cell as an example, a method for controlling the cell charging rate is provided, including:

[0183] S110: At 25℃, a model of the charging expansion force and charging rate of a lithium-ion battery cell during the charging process is pre-established, including the following steps:

[0184] S111: At 25℃, the charging rate of lithium-ion battery cells under different states of charge (SOC) during charging was tested. The different SOCs were 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, and 95%. The specific testing method involved adjusting the battery to the corresponding SOC using a 1C pulse, and then charging it with a constant current at different pulse rates for 30 seconds at that SOC. The maximum charging rate at which the voltage reached the upper limit (e.g., 4.2V) after 30 seconds was obtained, and the data on the rate of charge change with SOC were obtained. The test results are shown in Table 1.

[0185] Table 1

[0186] SOC / % Multiplier / C SOC / % Multiplier / C 0.95 0.50 0.45 6.60 0.90 1.50 0.40 6.80 0.85 2.50 0.35 6.80 0.80 4.00 0.30 7.00 0.75 5.00 0.25 7.30 0.70 6.00 0.20 7.50 0.65 6.20 0.15 7.80 0.60 6.20 0.10 8.00 0.55 6.50 0.05 8.20 0.50 6.50 0.00 8.50

[0187] Data fitting was performed on the data of the multiplier changing with SOC in Table 1, with SOC as the independent variable and multiplier as the dependent variable, to obtain the following results: Figure 4 The first functional relationship fitting curve shown is ( Figure 4 The dashed line in the diagram and the expression for the first function are as follows:

[0188]

[0189] Among them, the coefficient of determination R of the first functional relation expression 2 The value of 0.9891 indicates a high degree of curve fitting.

[0190] S112: At 25℃, the charging expansion force of lithium-ion battery cells under different states of charge (SOC) during charging was tested. The different SOCs were 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, and 100%. An in-situ expansion tester 10 was used to test the expansion force of the lithium-ion battery cells, and the data on the change of expansion force with SOC were obtained. The test results are shown in Table 2.

[0191] Table 2

[0192] SOC / % Expansion force / N SOC / % Expansion force / N 1 72 0.45 33 0.95 67 0.40 29 0.90 65 0.35 25 0.85 61 0.30 20 0.80 55 0.25 18 0.75 54 0.20 15 0.70 47 0.15 8 0.65 46 0.10 7.1 0.60 43 0.05 4 0.55 42 0.00 0 0.50 40

[0193] Data fitting was performed on the expansion force versus SOC data in Table 2, with SOC as the independent variable and expansion force as the dependent variable, to obtain the following results: Figure 5 The second function relationship fitting curve shown is ( Figure 5 The dashed line in the diagram and the expression for the second function are as follows:

[0194] F 膨胀力 =71.408X SOC +0.0628

[0195] Among them, the coefficient of determination R of the second functional relation expression 2 The value of 0.9947 indicates a high degree of curve fitting.

[0196] S113: By associating the first functional relationship expression with the second functional relationship expression, the expansion force and rate capability model of lithium-ion battery cells at 25℃ is obtained as follows:

[0197]

[0198] S120: Input the recommended expansion force threshold of the battery cell, such as 61N, into the expansion force and rate model corresponding to step S113 above to obtain the target charging rate of the lithium battery cell under test at 25℃ as 2.5C. Here, 61N is calculated based on the cell size. The recommended expansion pressure threshold P of the cell is 0.02MPa, and the cell size S is 56mm*55mm. According to the formula: F=P*S, the recommended expansion force threshold F of the cell is 61N.

[0199] S130: At an ambient temperature of 25°C, control the lithium battery cell under test to be charged at a charging rate not exceeding the target charging rate.

[0200] A second aspect of the invention, referring to Figure 6 A system 200 for determining the charging rate of a battery cell is provided, comprising:

[0201] The model storage module 210 is used to pre-store the charging expansion force and charging rate model of the battery cell during the charging process under preset working conditions.

[0202] The target rate determination module 220 is used to determine the target charging rate of the battery cell under the preset operating conditions based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to the different types of battery cells during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell.

[0203] The control module 230 is used to control the battery cell under test to be charged at a charging rate not exceeding the target charging rate under the preset operating conditions.

[0204] Specifically, the battery cell charging rate determination system 200 provided in the various embodiments of the present invention is used to execute the battery cell charging rate determination method provided in any embodiment of the present application. Its specific technical effects are consistent with the battery cell charging rate determination method, and will not be described in detail in the embodiments of the present application.

[0205] In some embodiments, the target magnification determination module 220 is specifically used for:

[0206] Based on the type of the battery cell under test, determine the charging expansion force and charging rate model corresponding to the battery cell of the same type as the battery cell under test;

[0207] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model of the same type of battery cell to obtain the target charging rate of the battery cell under test.

[0208] In some embodiments, the model storage module 210 is specifically used for:

[0209] Under preset operating conditions, a model of the charging expansion force and charging rate of the battery cell during the charging process is pre-established.

[0210] In some embodiments, the model storage module 210 is specifically used for:

[0211] Under preset operating conditions, a pre-established model of the charging expansion force and charging rate corresponding to different types of battery cells during the charging process is created.

[0212] In some embodiments, the control module 230 is specifically used for:

[0213] Based on the current operating condition of the battery cell under test, the target charging rate of the battery cell under test is adjusted in real time, and the battery cell under test is controlled to be charged at a charging rate not exceeding the real-time adjusted target charging rate.

[0214] In some implementations, the preset operating conditions include a preset temperature.

[0215] In some implementations, reference Figure 7 The model storage module 210 includes:

[0216] The first model building unit 211 is used to obtain the charging rate corresponding to different states of charge of the battery cell during the charging process under preset working conditions, and to establish a model of the relationship between the charging rate and the state of charge of the battery cell.

[0217] The second model building unit 212 is used to obtain the charging expansion force corresponding to different states of charge of the battery cell during the charging process under the preset working conditions, and to establish a model of the relationship between the charging expansion force and the state of charge of the battery cell.

[0218] The third model construction unit 213 establishes a model of the charging expansion force and charging rate of the battery cell based on the relationship model between the charging rate and the state of charge of the battery cell and the relationship model between the charging expansion force and the state of charge of the battery cell.

[0219] In some implementations, the first model building unit 211 is specifically used for:

[0220] Data fitting is performed on the charging rate corresponding to different states of charge of the battery cell during the charging process to establish a first functional relationship expression with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0221] In some embodiments, the first model building unit 211 is further configured to:

[0222] First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage after the preset charging time is obtained. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

[0223] In some embodiments, the second model building unit 212 is specifically used for:

[0224] Data fitting is performed on the charging expansion force corresponding to different states of charge of the battery cell during the charging process to establish a second functional relationship expression with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0225] In some embodiments, the second model building unit 212 includes: an in-situ expansion tester 10, which is used to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0226] In some embodiments, the in-situ expansion tester 10 includes:

[0227] Clamp 11 is used to clamp battery cell 15;

[0228] The charging module 12 is used to perform charging tests on the battery cell 15 under different states of charge when the battery cell 15 is in a clamped state, and to record the charging parameters of the battery cell 15 during the charging process; the charging parameters include current, voltage and time.

[0229] Pressure sensor 13 is used to obtain the expansion force value of battery cell 15 during charging;

[0230] The data processing module 14 is used to process the expansion force value of the battery cell 15 obtained by the pressure sensor 13 and the charging parameters recorded by the charging module 12 to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0231] In some implementations, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0232] In some implementations, the first functional relational expression is:

[0233]

[0234] Among them, Y 倍率 X represents the cell charging rate. SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0235] In some implementations, the second functional relational expression is:

[0236]

[0237] Among them, F 膨胀力 X represents the cell's charging expansion force. SOC The state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0238] In some embodiments, the charging expansion force and charging rate model is as follows:

[0239]

[0240] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0241] A third aspect of the invention, with reference to Figure 8 A method for determining the type of battery cell is provided, including:

[0242] S320: Based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, determine the target charging rate of different types of battery cells; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell;

[0243] S330: Determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test according to the target charging rate of the different types of cells.

[0244] Specifically, different types of battery cells refer to cells with at least one difference in model (or size) and material. The difference in material refers to the different materials used for the positive electrode and / or negative electrode. Based on industry-standard recommended expansion force thresholds for battery cells and charging expansion force versus charging rate models for different cell types during charging, target charging rates are determined for different cell types. These target charging rates represent the upper limit of the charging rate for the corresponding cell type. This allows for control over the charging of the tested cell during subsequent charging processes, ensuring it does not exceed the target charging rate, preventing excessive cell expansion, and improving the performance and safety of the cell, battery module, and the entire battery pack.

[0245] The test involves determining the maximum charging rate of an unknown type of battery cell under a preset expansion force. This maximum charging rate is then compared with the target charging rates of different cell types to identify the cell type. In practical applications, a cell type can be selected as the target cell type based on actual needs. For example, the target cell type with the desired charging rate can be selected from the target charging rates of different cell types. For instance, the cell with the highest target charging rate can be selected as the target cell type; or, at least one cell with a target charging rate exceeding a threshold value can be selected as the target cell type; or, at least one cell with a target charging rate falling within the threshold value range can be selected as the target cell type.

[0246] In some implementations, step S320 is further included before:

[0247] S310: Under preset operating conditions, pre-establish models of charging expansion force and charging rate for different types of battery cells during the charging process.

[0248] Specifically, under preset operating conditions, various types of battery cells are charged to determine the charging expansion force and charging rate models for different types of cells. Based on the type of the battery cell under test, a charging expansion force and charging rate model corresponding to the same type of battery cell under test is determined to predict the target charging rate of the battery cell under test, thereby improving prediction accuracy.

[0249] In some implementations, in S310, the preset operating condition includes a preset temperature.

[0250] In some implementations, S310 specifically includes:

[0251] S311: Under preset operating conditions, obtain the charging rate corresponding to different states of charge for each type of battery cell during the charging process, and establish a model of the relationship between the charging rate and the state of charge for each type of battery cell.

[0252] S312: Under the preset working conditions, obtain the charging expansion force corresponding to different states of charge for each type of battery cell during the charging process, and establish a model of the relationship between the charging expansion force and the state of charge for each type of battery cell.

[0253] S313: Based on the relationship model between charging rate and state of charge of any type of battery cell, and the relationship model between charging expansion force and state of charge of the corresponding type of battery cell, establish a model of charging expansion force and charging rate for that type of battery cell.

[0254] In some implementations, S311 specifically includes:

[0255] Data fitting is performed on the charging rate corresponding to different states of charge during the charging process for each type of battery cell, and a first functional relationship expression is established with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0256] In some implementations, S311, obtaining the charging rate corresponding to different states of charge for each type of battery cell during charging includes:

[0257] First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage is obtained after the preset charging time. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

[0258] In some implementations, S312 specifically includes:

[0259] Data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. A second functional relationship expression is established with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0260] In some implementations, in S312, an in-situ expansion tester 10 is used to obtain the charging expansion force corresponding to different charging states of each type of battery cell 15 during the charging process.

[0261] In some embodiments, the in-situ expansion tester 10 includes:

[0262] Clamp 11 is used to clamp battery cell 15;

[0263] The charging module 12 is used to perform charging tests on the battery cell 15 under different states of charge when the battery cell 15 is in a clamped state, and to record the charging parameters of the battery cell 15 during the charging process; the charging parameters include current, voltage and time.

[0264] Pressure sensor 13 is used to obtain the expansion force value of battery cell 15 during charging;

[0265] The data processing module 14 is used to process the expansion force value of the battery cell 15 obtained by the pressure sensor 13 and the charging parameters recorded by the charging module 12 to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0266] In some implementations, in S311 and S312, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0267] In some implementations, in S311, the first functional relational expression is:

[0268]

[0269] Among them, Y 倍率 X represents the cell charging rate. SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0270] In some implementations, in S312, the second functional relational expression is:

[0271]

[0272] Among them, F膨胀力 X represents the cell's charging expansion force. SOC The state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0273] In some implementations, in S313, the charging expansion force and charging rate model is as follows:

[0274]

[0275] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0276] It is understood that the specific technical effects of S310 are the same as those of S110, and will not be described in detail in the embodiments of this application.

[0277] In some implementations, S320 specifically includes:

[0278] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, and the target charging rate of different types of battery cells is obtained.

[0279] Specifically, each type of battery cell corresponds to a charging expansion force and charging rate model. The preset expansion force of the battery cell is input into the charging expansion force and charging rate models corresponding to at least two different types of battery cells to obtain the target charging rate of at least two different types of battery cells. Thus, the battery cell type with a higher target charging rate or a suitable rate according to actual needs can be selected as the target type battery cell.

[0280] In some implementations, S330 specifically includes:

[0281] The maximum charging rate of the cell under test is calculated by subtracting the target charging rate of the different types of cells, and the cell type with the smallest difference is selected as the type of the cell under test.

[0282] Specifically, under preset operating conditions, charging expansion force and charging rate models for different types of battery cells during charging are pre-established and stored in a database. The database records the charging expansion force and charging rate model for each type of battery cell under each preset operating condition; that is, the battery cell type, preset operating condition, and charging expansion force and charging rate model are stored in a one-to-one correspondence. Based on the current operating condition of the battery cell under test, the charging expansion force and charging rate model corresponding to the same or similar operating condition is retrieved from the database. The preset expansion force of the battery cell is input into the retrieved charging expansion force and charging rate model to obtain the target charging rate for different types of battery cells under the current operating condition. A charging test is then conducted on the battery cell under test under the current operating condition to determine the maximum charging rate corresponding to reaching the preset expansion force. This maximum charging rate is then subtracted from the target charging rate for each type of battery cell under the current operating condition. The battery cell type with the smallest difference is selected as the type of battery cell under test under the current operating condition. Therefore, based on actual needs, a battery cell with an appropriate charging rate can be selected as the target type of battery cell under the current operating condition. In this example, by considering the current operating conditions of the cell under test, a cell of appropriate rate type can be selected.

[0283] Example 2

[0284] Taking a 30Ah soft-pack lithium-ion battery cell as an example, a method for determining the cell type is provided, including:

[0285] S310: At 25°C, a pre-established model of the charging expansion force and charging rate of lithium-ion batteries with different negative electrodes during the charging process is prepared. The specific implementation method is the same as S110, and will not be described in detail in the embodiments of this application. The model of the expansion force and charging rate of the graphite-based negative electrode lithium-ion battery is as follows:

[0286]

[0287] Among them, the coefficient of determination R in the above functional relationship expression 2 The value of 0.9625 indicates a high degree of curve fitting.

[0288] The model for the expansion force and rate capability of silicon-based anode lithium-ion batteries is as follows:

[0289]

[0290] Among them, the coefficient of determination R in the above functional relationship expression 2 The value of 0.9510 indicates a high degree of curve fitting.

[0291] S320: Substitute the preset expansion force of the battery cell into the two formulas above to obtain the maximum charging rate of the graphite-based and silicon-based lithium-ion batteries under this expansion force. The preset expansion force is 50N. The calculation results are: the maximum target charging rate of the graphite-based lithium-ion battery is 5C, and the maximum target charging rate of the silicon-based lithium-ion battery is 2C. Input the expansion force and rate model, battery material, and charging rate into the database.

[0292] S330: At an ambient temperature of 25°C, test the maximum charge rate of battery A under a 50N expansion force. Compare this maximum charge rate with the target charge rates of different types of cells in the database to determine the negative electrode material type of battery A. For example, if the maximum charge rate of battery A is 2.1C, then the negative electrode material type of battery A is silicon-based.

[0293] A fourth aspect of the present invention provides a system for determining the type of battery cell, comprising:

[0294] The model storage module is used to pre-store the charging expansion force and charging rate models corresponding to different types of battery cells during the charging process;

[0295] The target charging rate determination module determines the target charging rate for different types of battery cells based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell;

[0296] The cell type determination module is used to determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test according to the target charging rate of the different types of cells.

[0297] In some implementations, the model storage module is specifically used for:

[0298] Under preset operating conditions, a pre-established model of the charging expansion force and charging rate of the different types of battery cells during the charging process is created.

[0299] In some implementations, the preset operating conditions include a preset temperature.

[0300] In some embodiments, the model storage module includes:

[0301] The first model building unit is used to obtain the charging rate corresponding to different states of charge of each type of battery cell during the charging process under preset working conditions, and to establish a model of the relationship between the charging rate and the state of charge of each type of battery cell.

[0302] The second model building unit is used to obtain the charging expansion force corresponding to different states of charge of each type of battery cell during the charging process under the preset working conditions, and to establish a model of the relationship between the charging expansion force and the state of charge of each type of battery cell.

[0303] The third model construction unit establishes a model of charging expansion force and charging rate for a given type of battery cell, based on the relationship model between charging rate and state of charge for any type of battery cell and the relationship model between charging expansion force and state of charge for the corresponding type of battery cell.

[0304] In some implementations, the first model building unit is specifically used for:

[0305] Data fitting is performed on the charging rate corresponding to different states of charge during the charging process for each type of battery cell, and a first functional relationship expression is established with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

[0306] In some implementations, the first model building unit is further used for:

[0307] First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage is obtained after the preset charging time. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

[0308] In some implementations, the second model building unit is specifically used for:

[0309] Data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. A second functional relationship expression is established with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

[0310] In some embodiments, the second model building unit includes an in-situ expansion tester 10, which is used to obtain the charging expansion force corresponding to different charging states of each type of battery cell 15 during the charging process.

[0311] In some embodiments, the in-situ expansion tester 10 includes:

[0312] Clamp 11 is used to clamp battery cell 15;

[0313] The charging module 12 is used to perform charging tests on the battery cell 15 under different states of charge when the battery cell 15 is in a clamped state, and to record the charging parameters of the battery cell 15 during the charging process; the charging parameters include current, voltage and time.

[0314] Pressure sensor 13 is used to obtain the expansion force value of battery cell 15 during charging;

[0315] The data processing module 14 is used to process the expansion force value of the battery cell 15 obtained by the pressure sensor 13 and the charging parameters recorded by the charging module 12 to obtain the charging expansion force of the battery cell 15 under different charging states during the charging process.

[0316] In some implementations, the data fitting method includes at least one of the following: linear regression method and multinomial regression method.

[0317] In some implementations, the first functional relational expression is:

[0318]

[0319] Among them, Y 倍率 X represents the cell charging rate. SOC The state of charge is represented by A1 and B1, which represent different coefficients in the first functional relationship expression, and C1 represents the constant term in the first functional relationship expression; N represents the degree of the highest term in the first functional relationship expression, and N is an integer greater than or equal to 1.

[0320] In some implementations, the second functional relational expression is:

[0321]

[0322] Among them, F 膨胀力 X represents the cell's charging expansion force. SOC The state of charge is represented by A2 and B2, which represent different coefficients in the second functional relationship expression, and C2 represents the constant term in the second functional relationship expression; n represents the degree of the highest term in the second functional relationship expression, and n is an integer greater than or equal to 1.

[0323] In some embodiments, the charging expansion force and charging rate model is as follows:

[0324]

[0325] Where A3 and B3 represent different coefficients in the charging expansion force and charging rate model, C3 represents the constant term in the charging expansion force and charging rate model, and a represents the degree of the highest term in the charging expansion force and charging rate model, where a is an integer greater than or equal to 1.

[0326] In some implementations, the target magnification determination module is specifically used for:

[0327] The preset expansion force of the battery cell is input into the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, and the target charging rate of different types of battery cells is obtained.

[0328] In some embodiments, the cell type determination module is specifically used for:

[0329] The maximum charging rate of the cell under test is calculated by subtracting the target charging rate of the different types of cells, and the cell type with the smallest difference is selected as the type of the cell under test.

[0330] It should be noted that the cell type determination system provided in any embodiment of this application is used to execute the cell type determination method provided in each embodiment of this application, and its specific technical effects are consistent with the cell type determination method. The embodiments of this application will not be described in detail.

[0331] Figure 9 A schematic diagram of the structure of an electronic device according to an embodiment of this application is shown. Figure 9 As shown, in another aspect, this application also provides an electronic device 400, including one or more central processing units (CPUs) 401, which can perform various appropriate actions and processes according to programs stored in read-only memory (ROM) 402 or programs loaded from storage portion 408 into random access memory (RAM) 403. Various programs and data required for system operation are also stored in RAM 403. The CPU 401, ROM 402, and RAM 403 are interconnected via bus 404. Input / output (I / O) interface 405 is also connected to bus 404.

[0332] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0333] Specifically, according to embodiments of this disclosure, the above... Figure 1 , Figure 2 , Figure 8 The described process can be implemented as a computer software program. For example, embodiments of this disclosure include a computer program product comprising a computer program tangibly embodied on a machine-readable medium, the computer program containing program code for performing a method for controlling the charging rate of a battery cell. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411.

[0334] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0335] In another aspect, this application also provides a computer-readable storage medium, which may be a computer-readable storage medium included in the apparatus described in the above embodiments; or it may be a standalone computer-readable storage medium not assembled into a device. The computer-readable storage medium stores one or more programs, which are used by one or more processors to execute the cell charging rate control method described in this application.

[0336] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or operation, or by a combination of dedicated hardware and computer instructions.

[0337] The units or modules described in the embodiments of this application can be implemented in software or hardware. The described units or modules can also be located in a processor; for example, each unit can be a software program located in a computer or mobile smart device, or a separately configured hardware device. The names of these units or modules do not, in some cases, constitute a limitation on the unit or module itself.

[0338] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A method for controlling the charging rate of a battery cell, characterized in that, include: Based on the type of the battery cell under test, the preset expansion force of the battery cell, and the charging expansion force and charging rate model of the battery cell during the charging process, the target charging rate of the battery cell under test is determined; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell; The battery cell under test is controlled to be charged at a charging rate not exceeding the target charging rate; Specifically, under preset operating conditions, a model of the charging expansion force and charging rate of the battery cell during the charging process is pre-established, as follows: Under preset operating conditions, the charging rate corresponding to different states of charge of the battery cell during the charging process is obtained, and a model of the relationship between the charging rate and the state of charge of the battery cell is established. Under the preset working conditions, the charging expansion force of the battery cell under different states of charge during the charging process is obtained, and a model of the relationship between the charging expansion force and the state of charge of the battery cell is established. Based on the relationship model between the charging rate and the state of charge of the battery cell and the relationship model between the charging expansion force and the state of charge of the battery cell, a model of the charging expansion force and the charging rate of the battery cell is established.

2. The method for controlling the charging rate of a battery cell according to claim 1, characterized in that, The step of determining the target charging rate of the battery cell under test based on the type of the battery cell, the preset expansion force of the battery cell, and the charging expansion force and charging rate model of the battery cell during charging includes: Based on the type of the battery cell under test, determine the charging expansion force and charging rate model corresponding to the battery cell of the same type as the battery cell under test; The preset expansion force of the battery cell is input into the charging expansion force and charging rate model of the same type of battery cell to obtain the target charging rate of the battery cell under test.

3. The method for controlling the charging rate of a battery cell according to claim 1, characterized in that, A pre-established model of the charging expansion force and charging rate corresponding to different types of battery cells during the charging process is established.

4. The method for controlling the charging rate of a battery cell according to any one of claims 1-3, characterized in that, The step of controlling the battery cell under test to charge at a charging rate not exceeding the target charging rate includes: Based on the current operating condition of the battery cell under test, the target charging rate of the battery cell under test is adjusted in real time, and the battery cell under test is controlled to be charged at a charging rate not exceeding the real-time adjusted target charging rate.

5. The method for controlling the charging rate of a battery cell according to any one of claims 1-3, characterized in that, The preset operating conditions include a preset temperature.

6. The method for controlling the charging rate of a battery cell according to claim 1, characterized in that, The step of acquiring the charging rate corresponding to different states of charge of the battery cell during charging under preset operating conditions and establishing a model of the relationship between the charging rate and the state of charge of the battery cell includes: Data fitting is performed on the charging rate corresponding to different states of charge of the battery cell during the charging process to establish a first functional relationship expression with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

7. The method for controlling the charging rate of a battery cell according to claim 6, characterized in that, The acquisition of the charging rate corresponding to different states of charge of the battery cell during charging includes: First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage after the preset charging time is obtained. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

8. The method for controlling the charging rate of a battery cell according to claim 6, characterized in that, Under the preset operating conditions, the step of acquiring the charging expansion force of the battery cell under different states of charge during charging and establishing a model relating the charging expansion force of the battery cell to its state of charge includes: Data fitting is performed on the charging expansion force corresponding to different states of charge of the battery cell during the charging process to establish a second functional relationship expression with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

9. The method for controlling the charging rate of a battery cell according to claim 8, characterized in that, The charging expansion force of the battery cell under different charging states during the charging process was obtained using an in-situ expansion tester.

10. The method for controlling the charging rate of a battery cell according to claim 9, characterized in that, The in-situ expansion tester includes: Clamps are used to hold battery cells; The charging module is used to perform charging tests on the battery cell under different states of charge when the battery cell is in a clamped state, and to record the corresponding charging parameters of the battery cell during the charging process; the charging parameters include current, voltage and time. A pressure sensor is used to obtain the expansion force value of the battery cell during the charging process; The data processing module is used to process the cell expansion force value obtained by the pressure sensor and the charging parameters recorded by the charging module to obtain the charging expansion force corresponding to different charging states of the cell during the charging process.

11. The method for controlling the charging rate of a battery cell according to any one of claims 8-10, characterized in that, The data fitting method includes at least one of the following: linear regression method and multinomial regression method.

12. The method for controlling the charging rate of a battery cell according to claim 11, characterized in that, The first functional relational expression is: in, Indicates the cell charging rate. Indicates the state of charge. , Indicate the different coefficients in the first functional relational expression. This represents the constant term in the first functional relational expression; This indicates the degree of the highest term in the first functional relational expression. It is an integer greater than or equal to 1.

13. The method for controlling the charging rate of a battery cell according to claim 12, characterized in that, The second functional relational expression is: in, This indicates the expansion force of the battery cell during charging. Indicates the state of charge. , These represent the distinct coefficients in the second functional relational expression. This represents the constant term in the second functional relational expression; This indicates the degree of the highest term in the second functional relational expression. It is an integer greater than or equal to 1.

14. The method for controlling the charging rate of a battery cell according to claim 13, characterized in that, The charging expansion force and charging rate model is as follows: in, , These represent different coefficients in the charging expansion force and charging rate model. This represents the constant term in the charging expansion force and charging rate model; This indicates the degree of the highest term in the charging expansion force versus charging rate model. It is an integer greater than or equal to 1.

15. A control system for the charging rate of a battery cell, characterized in that, The control system is used to execute the cell charging rate control method according to any one of claims 1-14, the control system comprising: The model storage module is used to store the charging expansion force and charging rate model of the battery cell during the charging process; The target charging rate determination module is used to determine the target charging rate of the battery cell under test based on the type of the battery cell, the preset expansion force of the battery cell, and the charging expansion force and charging rate model of the battery cell during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell; The control module is used to control the battery cell under test to be charged at a charging rate not exceeding the target charging rate.

16. A method for determining the type of battery cell, characterized in that, include: Based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, the target charging rate of different types of battery cells is determined; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell. Determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test based on the target charging rate of the different types of cells. Specifically, under preset operating conditions, a pre-established model of the charging expansion force and charging rate corresponding to the different types of battery cells during the charging process is constructed, as follows: Under preset operating conditions, the charging rate corresponding to different states of charge of each type of battery cell during the charging process is obtained, and a model of the relationship between the charging rate and the state of charge of each type of battery cell is established. Under the preset working conditions, the charging expansion force corresponding to different states of charge of each type of battery cell during the charging process is obtained, and a model of the relationship between the charging expansion force and the state of charge of each type of battery cell is established. Based on the relationship model between charging rate and state of charge for any type of battery cell, and the relationship model between charging expansion force and state of charge for the corresponding type of battery cell, establish a model of charging expansion force and charging rate for that type of battery cell.

17. The method for determining the cell type according to claim 16, characterized in that, The process of determining the maximum charging rate of the battery cell under test under the preset expansion force, and then determining the type of the battery cell under test based on the target charging rates of different types of battery cells, includes: The maximum charging rate of the cell under test is calculated by subtracting the target charging rate of the different types of cells, and the cell type with the smallest difference is selected as the type of the cell under test.

18. The method for determining the cell type according to claim 16, characterized in that, The step of determining the target charging rate for different types of battery cells based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process includes: The preset expansion force of the battery cell is input into the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process, and the target charging rate of different types of battery cells is obtained.

19. The method for determining the cell type according to claim 16, characterized in that, The preset operating conditions include a preset temperature.

20. The method for determining the cell type according to claim 16, characterized in that, Under preset operating conditions, the charging rate corresponding to different states of charge for each type of battery cell during charging is obtained, and a model relating the charging rate to the state of charge for each type of battery cell is established. Data fitting is performed on the charging rate corresponding to different states of charge during the charging process for each type of battery cell, and a first functional relationship expression is established with either the charging rate or the state of charge as the independent variable and the other as the dependent variable. The first functional relationship expression is used as the relationship model between the charging rate and the state of charge.

21. The method for determining the cell type according to claim 20, characterized in that, The process of obtaining the charging rate corresponding to different states of charge for each type of battery cell during charging includes: First, the battery cell is adjusted to a certain state of charge using a preset pulse rate. In the state of charge, it is charged with a constant current at different rates for a preset time. The maximum charging rate corresponding to the upper limit voltage after the preset charging time is obtained. The maximum charging rate is taken as the charging rate of the battery cell in the state of charge.

22. The method for determining the cell type according to claim 20, characterized in that, Under the preset operating conditions, the charging expansion force corresponding to different states of charge for each type of battery cell during charging is obtained, and a model relating the charging expansion force to the state of charge for each type of battery cell is established, including: Data fitting is performed on the charging expansion force corresponding to different states of charge during the charging process for each type of battery cell. A second functional relationship expression is established with either the charging expansion force or the state of charge as the independent variable and the other as the dependent variable. The second functional relationship expression is used as the relationship model between the charging expansion force and the state of charge.

23. The method for determining the cell type according to claim 22, characterized in that, An in-situ expansion tester was used to obtain the charging expansion force corresponding to different charging states of each type of battery cell during the charging process.

24. The method for determining the cell type according to claim 23, characterized in that, The in-situ expansion tester includes: Clamps are used to hold battery cells; The charging module is used to perform charging tests on the battery cell under different states of charge when the battery cell is in a clamped state, and to record the corresponding charging parameters of the battery cell during the charging process; the charging parameters include current, voltage and time. A pressure sensor is used to obtain the expansion force value of the battery cell during the charging process; The data processing module is used to process the cell expansion force value obtained by the pressure sensor and the charging parameters recorded by the charging module to obtain the charging expansion force corresponding to different charging states of the cell during the charging process.

25. The method for determining the cell type according to any one of claims 22-24, characterized in that, The data fitting method includes at least one of the following: linear regression method and multinomial regression method.

26. The method for determining the cell type according to claim 25, characterized in that, The first functional relational expression is: in, Indicates the cell charging rate. Indicates the state of charge. , Indicate the different coefficients in the first functional relational expression. This represents the constant term in the first functional relational expression; This indicates the degree of the highest term in the first functional relational expression. It is an integer greater than or equal to 1.

27. The method for determining the cell type according to claim 26, characterized in that, The second functional relational expression is: in, This indicates the expansion force of the battery cell during charging. Indicates the state of charge. , These represent the distinct coefficients in the second functional relational expression. This represents the constant term in the second functional relational expression; This indicates the degree of the highest term in the second functional relational expression. It is an integer greater than or equal to 1.

28. The method for determining the cell type according to claim 27, characterized in that, The charging expansion force and charging rate model is as follows: in, , These represent different coefficients in the charging expansion force and charging rate model. This represents the constant term in the charging expansion force and charging rate model; This indicates the degree of the highest term in the charging expansion force versus charging rate model. It is an integer greater than or equal to 1.

29. A system for determining the type of battery cell, characterized in that, The determining system is used to perform the cell type determination method according to any one of claims 16-28, the determining system comprising: The model storage module is used to pre-store the charging expansion force and charging rate models corresponding to different types of battery cells during the charging process; The target charging rate determination module determines the target charging rate for different types of battery cells based on the preset expansion force of the battery cell and the charging expansion force and charging rate model corresponding to different types of battery cells during the charging process; wherein, the preset expansion force of the battery cell is the recommended expansion force threshold of the battery cell; The cell type determination module is used to determine the maximum charging rate of the cell under test under the preset expansion force, and then determine the type of the cell under test according to the target charging rate of the different types of cells.

30. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors perform the steps of the cell charging rate control method as described in any one of claims 1-14, or the steps of the cell type determination method as described in any one of claims 16-28.

31. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the cell charging rate control method according to any one of claims 1-14, or the steps of the cell type determination method according to any one of claims 16-28.

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