A method, device, electronic device and storage medium for determining preload force of a battery cell

Abstract

The present application provides a method, device, electronic device and storage medium for determining the preload force of a battery cell, which relates to the field of battery technology. The method measures the change in compression of a target packaged battery cell under different pressure values, draws the strain-pressure curve of the target packaged battery cell, and analyzes the optimum preload force of the target packaged battery cell according to the elastic modulus of the target packaged battery cell, wherein the elastic modulus of the target packaged battery cell is the slope of the strain-pressure curve. Compared with the prior art test cycle of at least one month for the optimum preload force, the present application can be completed in one day, greatly improving the test efficiency. Moreover, in some embodiments, the optimum preload force determined is further verified by drawing the charge transfer resistance-pressure curve to determine whether the preload force determined for the target packaged battery cell is accurate, thereby improving the test reliability.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a method, device, electronic device and storage medium for determining a preload force of a battery cell. Background Art

[0002] A battery cell module is composed of multiple battery cells stacked in a certain arrangement. At the same time, the volume of the module is limited to a certain extent. Therefore, the battery cells in the module will be subject to a certain pressure in the initial state. Appropriate pressure will promote the electrochemical performance of the battery cells and extend the life of the battery cells.

[0003] Currently, the selection of appropriate preload force for battery cells is mostly based on long cycles under different preload forces, and then judged according to the cycle life of the battery cells. Long cycles generally require more than 600 cycles. Calculated according to the current of 1C, it takes at least 2 months, which is very time-consuming and resource-intensive. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a method, device, electronic device and storage medium for determining the pre-tightening force of a battery cell, which can analyze the fitting state inside the battery cell from the perspective of elastic modulus, quickly determine the optimal pre-tightening force of the battery cell, and improve efficiency.

[0005] In a first aspect, the present application provides a method for determining a preload force of a battery cell, the method comprising the following steps:

[0006] Selecting a target packaged battery cell, and measuring a compression change value of the target packaged battery cell under different pressure values;

[0007] Draw a strain-pressure curve of the target packaged battery cell according to the measured compression change values ​​of the target packaged battery cell under different pressures;

[0008] The drawn strain-pressure curve of the target packaged battery cell is analyzed to determine the pressure value of the target packaged battery cell and use it as the preload force of the target packaged battery cell.

[0009] In a possible implementation manner, measuring the compression change value of the target packaged battery cell under different pressure values ​​includes the following steps:

[0010] Placing the bottom surface of the target packaged battery cell on a workbench, and measuring the initial thickness value of the target packaged battery cell;

[0011] Applying pressure to the front of the target packaged battery cell according to the set pressure value, and measuring the thickness value of the target packaged battery cell under different pressure values;

[0012] According to the initial thickness value of the target packaged battery cell and the thickness values ​​under different pressure values, the compression amount change value of the target packaged battery cell under different pressure values ​​is determined.

[0013] In a possible implementation manner, the strain-pressure curve of the target packaged battery cell is drawn in the following manner:

[0014] Draw a strain-pressure discrete point diagram according to the compression change value of the target packaged battery cell under different measured pressures;

[0015] The discrete points in the strain-pressure discrete point diagram are fitted based on the least squares method to obtain the strain-pressure curve of the target packaged battery cell.

[0016] In a possible implementation manner, analyzing the drawn strain-pressure curve of the target packaged battery cell to determine the pressure value of the target packaged battery cell as the preload force of the target packaged battery cell includes the following steps:

[0017] Determining the elastic modulus of the target packaged battery cell based on the strain-pressure curve of the target packaged battery cell; wherein the elastic modulus is represented by the slope of the strain-pressure curve of the target packaged battery cell;

[0018] If it is observed that the strain-pressure curve of the target packaged battery cell has a slope inflection point, the pressure value corresponding to the slope inflection point in the strain-pressure curve of the target packaged battery cell is used as the preload force of the target packaged battery cell.

[0019] In a possible implementation, the elastic modulus is determined by the following formula:

[0020] E=(F / S) / (dL / L0)=P / (dL / L0);

[0021] Among them, F is the pressure applied to the front side of the target packaged battery cell; S is the area of ​​the front side of the target packaged battery cell; L0 is the initial thickness of the target packaged battery cell; dL is the change in thickness when pressure is applied to the front side of the target packaged battery cell.

[0022] In a possible implementation, after the pre-tightening force of the target packaged battery cell is determined, it is verified whether the determined pre-tightening force of the target packaged battery cell is accurate.

[0023] In a possible implementation manner, whether the determined preload force of the target packaged battery cell is accurate is verified in the following manner:

[0024] Obtaining the charge transfer resistance of the target packaged battery cell under different pressures;

[0025] It is detected whether the charge transfer resistance of the target packaged battery cell under the pressure corresponding to the pre-tightening force is the smallest. If so, it is determined that the pre-tightening force of the target packaged battery cell is accurate.

[0026] In a second aspect, the present application provides a device for determining a preload force of a battery cell, the device comprising:

[0027] A measuring module, used for selecting a target packaged battery cell and measuring a change in compression of the target packaged battery cell under different pressure values;

[0028] A drawing module, used for drawing a strain-pressure curve of the target packaged battery cell according to the measured compression change value of the target packaged battery cell under different pressures;

[0029] The determination module is used to analyze the drawn strain-pressure curve of the target packaged battery cell and determine the pressure value of the target packaged battery cell as the preload force of the target packaged battery cell.

[0030] In a third aspect, the present application provides an electronic device, comprising: a processor, a memory and a bus, the memory storing machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate through the bus, and when the machine-readable instructions are executed by the processor, the steps of the method for determining the preload force of the battery cell as described in the first aspect are performed.

[0031] In a fourth aspect, the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the preload force of a battery cell as described in the first aspect are executed.

[0032] The present embodiment provides a method, device, electronic device and storage medium for determining the preload force of a battery cell. The method selects a target packaged battery cell and measures the compression change value of the target packaged battery cell under different pressure values; draws the strain-pressure curve of the target packaged battery cell according to the measured compression change value of the target packaged battery cell under different pressures; analyzes the drawn strain-pressure curve of the target packaged battery cell to determine the pressure value of the target packaged battery cell and use it as the preload force of the target packaged battery cell. It can be seen that the optimal preload force of the target packaged battery cell can be quickly determined by analyzing the strain-pressure curve. Compared with the prior art, it does not require a large number of long-cycle experiments, avoids waste of resources, and improves experimental efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a flow chart of a method for determining the preload force of a battery cell according to an embodiment of the present application;

[0035] Figure 2 A schematic diagram of applying pressure to a target packaged battery cell in one embodiment of the present application;

[0036] Figure 3 A flow chart for drawing a strain-pressure curve of a target packaged battery cell in one embodiment of the present application;

[0037] Figure 4 A schematic diagram of a strain-pressure curve of a target packaged battery cell drawn in an embodiment of the present application;

[0038] Figure 5 A schematic diagram of verifying whether the preload force of the target packaged battery cell is accurate in one embodiment of the present application;

[0039] Figure 6 A schematic diagram of a charge transfer resistance-pressure curve drawn in an embodiment of the present application;

[0040] Figure 7 It is a structural block diagram of a device for determining a preload force of a battery cell according to an embodiment of the present application;

[0041] Figure 8 It is a structural block diagram of an electronic device described in an embodiment of the present application. DETAILED DESCRIPTION

[0042] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of order, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0043] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application usually described and marked in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0044] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0045] In view of the technical problems raised by the background technology, the present application provides a method, device, electronic device and storage medium for determining the pre-tightening force of a battery cell, which can analyze the fitting state inside the battery cell from the perspective of elastic modulus, quickly determine the optimal pre-tightening force of the battery cell, and improve efficiency.

[0046] See the instruction manual Figure 1 In one embodiment, the present application provides a method for determining a preload force of a battery cell, the method comprising the following steps:

[0047] S1. Select a target packaged battery cell and measure the compression change value of the target packaged battery cell under different pressure values;

[0048] In an embodiment of the present application, the method for determining the preload force of the battery cell runs on a terminal device or a server; wherein the terminal device may be a terminal device of a service provider. When the method for determining the preload force of the battery cell runs on a server, the method for determining the preload force of the battery cell may be implemented and executed based on a cloud interaction system, wherein the cloud interaction system includes at least a server and a client device (ie, a terminal device).

[0049] In step S1, when measuring the pressure of the selected target packaged battery cell, a certain tooling may be used. Figure 2 , the bottom surface of the selected target packaged battery cell is first placed on the workbench of the tooling, and then a certain pressure is applied to the front surface of the target packaged battery cell from above through the force-applying device.

[0050] Specifically, in this embodiment, in order to better analyze the strain-pressure curve of the target packaged battery cell later, the first battery cell and the second battery cell of the same packaging standard are selected (the first battery cell and the second battery cell have different capacities and different packaging volumes). Among them, when measuring the pressure of the first battery cell, the bottom surface of the first battery cell is first placed on the workbench, and the initial thickness value of the first battery cell is measured; then, according to the set pressure value, pressure is applied to the front of the first battery cell in turn, and the thickness values ​​of the first battery cell at different pressure values ​​are measured; finally, according to the initial thickness value of the first battery cell and the thickness values ​​at different pressure values, the compression change value of the first battery cell, that is, the thickness value change, is determined. In one embodiment, the pressure value applied to the first battery cell and the compression change value can be referred to Table 1, that is, the pressure values ​​applied to the front of the first battery cell are 0.01Mpa, 0.02Mpa, 0.03Mpa, 0.04Mpa, 0.05Mpa, 0.06Mpa, 0.07Mpa, 0.08Mpa, 0.09Mpa, 0.1Mpa, 0.15Mpa, and 0.2Mpa, respectively. It can be seen that the set pressure values ​​are relatively small, that is, relatively close, on the one hand to avoid damage to the battery cell due to a large pressure value, and on the other hand to better draw the strain-pressure curve in the subsequent sequence; in addition, when measuring the thickness value of the first battery cell under different pressure values, the thickness value of the first battery cell under the pressure value should be recorded only after the force-applying device applies the corresponding pressure value to the first battery cell and when the compressed thickness of the first battery cell does not change. After recording the thickness value of the first battery cell under the pressure value, the next set pressure value is applied to the first battery cell.

[0051] Since the process of measuring the pressure of the second battery cell is similar to that of measuring the pressure of the first battery cell, it will not be described in detail here. The reason for setting the front side (force application side) and the bottom side (placement side) of the battery cell is to avoid the influence of errors in measuring the pressure of the second battery cell and the first battery cell respectively.

[0052] Pressure / Mpa 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 0.15 0.2 Cell1 / % 0 2.3214 2.6962 3.1299 3.4261 3.6700 3.9196 4.1252 4.3588 4.7074 4.9504 5.6672 6.3074 Cell2 / & 0 3.7570 4.3455 4.7457 5.0205 5.2990 5.5663 5.8775 6.0663 6.3373 6.4906 7.4635 7.8242

[0053] Table 1

[0054] S2. Draw a strain-pressure curve of the target packaged battery cell according to the measured compression change values ​​of the target packaged battery cell under different pressures;

[0055] For details, see the attached manual. Figure 3 In step S2, drawing the strain-pressure curve of the target packaged battery cell includes the following steps:

[0056] S201, drawing a strain-pressure discrete point diagram according to the measured compression change values ​​of the target packaged battery cell under different pressures;

[0057] S202 , fitting the discrete points in the strain-pressure discrete point diagram based on the least squares method to obtain the strain-pressure curve of the target packaged battery cell.

[0058] In step S201-202, that is, referring to Table 1 above, according to the measured compression change values ​​of the first battery cell and the second battery cell under different pressures, a coordinate system with the ordinate being pressure and the abscissa being strain is drawn, wherein the strain is the compression change value, which is expressed as a % value here. Although thirteen relatively close pressure values ​​are set in the present application, and the compression change values ​​of the first battery cell and the second battery cell under the thirteen pressure values ​​are measured, it is still a discrete point diagram, which is not convenient for analysis, so the least squares method is used to fit the discrete points in the strain-pressure discrete point diagram to obtain a smoother line. Among them, the strain-pressure curve drawn for the first battery cell and the second battery cell can be found in the attached figure of the specification. Figure 4 .

[0059] In one embodiment, when the least square method is used to fit the discrete points in the strain-pressure discrete point diagram, a series of discrete point coordinates (x i ,y i ), design a linear function F(x) = a1x + a0, by making e = ∑(y i -F(x i )) 2 The minimum value is taken to determine the unknown parameters a1 and a0 of the straight line, thereby determining the fitted strain-pressure curve.

[0060] In other embodiments, Bezier curve fitting, Lagrange interpolation, etc. may be used to fit the discrete points in the strain-pressure discrete point diagram, and this application does not limit or fix this.

[0061] S3. Analyze the drawn strain-pressure curve of the target packaged battery cell, determine the pressure value of the target packaged battery cell, and use it as the preload force of the target packaged battery cell.

[0062] In step S3, when analyzing the drawn strain-pressure curve of the target packaged battery cell, its slope, that is, the elastic modulus of the target packaged battery cell, is mainly referred to, which is a measure of the object's ability to resist elastic deformation.

[0063] In this application, the elastic modulus is determined by the following formula:

[0064] E=(F / S) / (dL / L0)=P / (dL / L0);

[0065] Among them, F is the pressure applied to the front side of the target packaged battery cell; S is the area of ​​the front side of the target packaged battery cell; L0 is the initial thickness of the target packaged battery cell; dL is the change in thickness when pressure is applied to the front side of the target packaged battery cell.

[0066] Furthermore, the elastic modulus calculation formula can be used to obtain P=E*dL / L0. Since the strain is expressed as a % value in the present application, P=k*100*dL / L0, where K is the slope.

[0067] See the instruction manual Figure 4 Whether it is the strain-pressure curve of the first battery cell or the strain-pressure curve of the second battery cell, there is an obvious inflection point in the slope, that is, 0.01Mpa-0.08Mpa and 0.09Mpa-0.2Mpa present two fitting lines with different slopes. Therefore, it can be determined that 0.08Mpa is the optimal preload force for the battery cell under this packaging standard. This is because if it is reduced on this basis, the body of the battery cell module will increase; if it is increased on this basis, it will significantly change the fitting state of the battery cell and may cause deformation of the internal material.

[0068] Furthermore, after determining the preload force of the target packaged battery cell, it is necessary to verify whether the determined preload force of the target packaged battery cell is accurate. Figure 5 In one embodiment, the accuracy of the preload force of the target packaged battery cell is verified by:

[0069] P1. Obtain the charge transfer resistance of the target packaged battery cell under different pressures;

[0070] P2. Detect whether the charge transfer resistance of the target packaged battery cell under the pressure corresponding to the pre-tightening force is the smallest. If so, determine that the pre-tightening force of the target packaged battery cell is accurate.

[0071] In steps P1-P2, a special tool can be used to test the target packaged battery cells under different pressures to obtain the charge transfer resistance of the target packaged battery cells under different pressures. The charge transfer resistance is used to indicate the difficulty of the charge transfer process through the interface between the electrode and the electrolyte solution during the electrode process. That is, the smaller the charge transfer resistance of the battery cell, the more favorable the pressure is for promoting charge transfer. Therefore, by detecting the charge transfer resistance of the battery cell, it can be determined whether the electrochemical performance of the battery cell is optimal. Then, by obtaining the charge transfer resistance of the target packaged battery cell under different pressures, it is verified whether the charge transfer resistance of the target packaged battery cell under the pressure corresponding to the determined preload force is the smallest. If it is the smallest, it is determined that the preload force of the determined target packaged battery cell is accurate. If it is not the smallest and is not within the minimum value area, it is determined that the preload force of the determined target packaged battery cell is wrong.

[0072] In this embodiment, three battery cells with the same packaging standard as the first battery cell and the second battery cell are tested to obtain their charge transfer resistance under different pressures, and a charge transfer resistance-pressure curve is drawn according to the obtained charge transfer resistance under different pressures. Figure 6 It can be seen that the charge transfer resistance of the three cells at 0.08Mpa is close to zero, while the charge transfer resistance of the three cells at 0.01Mpa-0.07Mpa is between 0.22mΩ-0.3mΩ, and the charge transfer resistance of the three cells at 0.09Mpa-0.2Mpa is between 0.22mΩ-0.49mΩ, that is, the verification result is consistent with that in step S3, which illustrates the effectiveness and reliability of the experiment, and can determine that the preload force of the target packaged cell determined above is accurate.

[0073] The present application provides a method for determining the preload force of a battery cell, which measures the change in compression of the target packaged battery cell under different pressure values, draws the strain-pressure curve of the target packaged battery cell, and analyzes the optimal preload force of the target packaged battery cell according to the elastic modulus of the target packaged battery cell, wherein the elastic modulus of the target packaged battery cell is the slope of the strain-pressure curve; compared with the prior art test cycle of at least one month for the optimal preload force, the present application can be completed in one day, greatly improving the test efficiency. Moreover, in some embodiments, the determined optimal preload force is further verified by drawing a charge transfer resistance-pressure curve to determine whether the preload force determined for the target packaged battery cell is accurate, thereby improving the test reliability.

[0074] Based on the same inventive concept, an embodiment of the present application also provides a device for determining the pre-tightening force of a battery cell. Since the principle of solving the problem by the device in the embodiment of the present application is similar to the method for determining the pre-tightening force of a battery cell mentioned above in the embodiment of the present application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be repeated.

[0075] As the instruction manual Figure 7 As shown, the present application also provides a device for determining the preload force of a battery cell, the device comprising:

[0076] The measuring module 701 is used to select a target packaged battery cell and measure a compression change value of the target packaged battery cell under different pressure values;

[0077] A drawing module 702 is used to draw a strain-pressure curve of the target packaged battery cell according to the measured compression change value of the target packaged battery cell under different pressures;

[0078] The determination module 703 is used to analyze the drawn strain-pressure curve of the target packaged battery cell and determine the pressure value of the target packaged battery cell as the preload force of the target packaged battery cell.

[0079] In some embodiments, the measuring module 701 measures the compression change value of the target packaged battery cell under different pressure values, including:

[0080] Placing the bottom surface of the target packaged battery cell on a workbench, and measuring the initial thickness value of the target packaged battery cell;

[0081] Applying pressure to the front of the target packaged battery cell according to the set pressure value, and measuring the thickness value of the target packaged battery cell under different pressure values;

[0082] According to the initial thickness value of the target packaged battery cell and the thickness values ​​under different pressure values, the compression amount change value of the target packaged battery cell under different pressure values ​​is determined.

[0083] In some implementations, the drawing module 702 draws the strain-pressure curve of the target packaged battery cell, including:

[0084] Draw a strain-pressure discrete point diagram according to the compression change value of the target packaged battery cell under different measured pressures;

[0085] The discrete points in the strain-pressure discrete point diagram are fitted based on the least squares method to obtain the strain-pressure curve of the target packaged battery cell.

[0086] In some implementations, the determination module 703 analyzes the drawn strain-pressure curve of the target packaged battery cell to determine the pressure value of the target packaged battery cell as the preload force of the target packaged battery cell, including:

[0087] Determining the elastic modulus of the target packaged battery cell based on the strain-pressure curve of the target packaged battery cell; wherein the elastic modulus is represented by the slope of the strain-pressure curve of the target packaged battery cell;

[0088] If it is observed that the strain-pressure curve of the target packaged battery cell has a slope inflection point, the pressure value corresponding to the slope inflection point in the strain-pressure curve of the target packaged battery cell is used as the preload force of the target packaged battery cell.

[0089] In some implementations, the determination module 703 determines the elastic modulus by the following formula:

[0090] E=(F / S) / (dL / L0)=P / (dL / L0);

[0091] Among them, F is the pressure applied to the front side of the target packaged battery cell; S is the area of ​​the front side of the target packaged battery cell; L0 is the initial thickness of the target packaged battery cell; dL is the change in thickness when pressure is applied to the front side of the target packaged battery cell.

[0092] In some embodiments, the device further comprises:

[0093] The verification module is used to verify whether the determined pre-tightening force of the target packaged battery cell is accurate after determining the pre-tightening force of the target packaged battery cell.

[0094] In some embodiments, the verification module verifies whether the determined preload force of the target packaged battery cell is accurate, including:

[0095] Obtaining the charge transfer resistance of the target packaged battery cell under different pressures;

[0096] It is detected whether the charge transfer resistance of the target packaged battery cell under the pressure corresponding to the pre-tightening force is the smallest. If so, it is determined that the pre-tightening force of the target packaged battery cell is accurate.

[0097] The present application provides a device for determining the preload force of a battery cell. The device selects a target packaged battery cell through a measurement module, and measures the compression change value of the target packaged battery cell under different pressure values; the device draws the strain-pressure curve of the target packaged battery cell according to the measured compression change value of the target packaged battery cell under different pressures through a drawing module; the device analyzes the drawn strain-pressure curve of the target packaged battery cell through a determination module, determines the pressure value of the target packaged battery cell, and uses it as the preload force of the target packaged battery cell. It can be seen that the optimal preload force of the target packaged battery cell can be quickly determined by analyzing the strain-pressure curve. Compared with the prior art, it does not require a large number of long-cycle experiments, avoids waste of resources, and improves experimental efficiency.

[0098] Based on the same concept of the present invention, the specification is attached Figure 8 As shown, the structure of an electronic device 800 provided in an embodiment of the present application includes: at least one processor 801, at least one network interface 804 or other user interface 803, a memory 805, and at least one communication bus 802. The communication bus 802 is used to realize the connection and communication between these components. The electronic device 800 optionally includes a user interface 803, including a display (for example, a touch screen, LCD, CRT, holographic imaging (Holographic) or projection (Projector), etc.), a keyboard or a pointing device (for example, a mouse, a trackball (trackball), a touch pad or a touch screen, etc.).

[0099] The memory 805 may include a read-only memory and a random access memory, and provides instructions and data to the processor 801. A portion of the memory 805 may also include a non-volatile random access memory (NVRAM).

[0100] In some embodiments, the memory 805 stores the following elements, which may be protected modules or data structures, or a subset thereof, or an extended set thereof:

[0101] Operating system 8051, including various system programs, used to implement various basic services and handle hardware-based tasks;

[0102] The application module 8052 includes various application programs, such as a launcher, a media player, a browser, etc., which are used to implement various application services.

[0103] In an embodiment of the present application, by calling the program or instructions stored in the memory 805, the processor 801 is used to execute steps in a method for determining the preload force of a battery cell, and can analyze the fitting state inside the battery cell from the perspective of the elastic modulus, quickly determine the optimal preload force of the battery cell, and improve efficiency.

[0104] The present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps in the method for determining the preload force of a battery cell are executed.

[0105] Specifically, the storage medium can be a general storage medium, such as a mobile disk, a hard disk, etc. When the computer program on the storage medium is run, the above-mentioned method for determining the preload force of the battery cell can be executed.

[0106] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0107] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] In addition, each functional unit in the embodiments provided in the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0109] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program codes.

[0110] Finally, it should be noted that the above embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the aforementioned embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application. They should all be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for determining the preload force of a battery cell, characterized in that: The method comprises the following steps: Selecting a target packaged battery cell, and measuring a compression change value of the target packaged battery cell under different pressure values; Draw a strain-pressure curve of the target packaged battery cell according to the measured compression change values ​​of the target packaged battery cell under different pressures; The drawn strain-pressure curve of the target packaged battery cell is analyzed to determine the pressure value of the target packaged battery cell and use it as the preload force of the target packaged battery cell; wherein, the elastic modulus of the target packaged battery cell is determined based on the strain-pressure curve of the target packaged battery cell; wherein, the elastic modulus is represented by the slope of the strain-pressure curve of the target packaged battery cell; if a slope inflection point is observed in the strain-pressure curve of the target packaged battery cell; the pressure value corresponding to the slope inflection point in the strain-pressure curve of the target packaged battery cell is used as the preload force of the target packaged battery cell.

2. A method for determining the preload force of a battery cell according to claim 1, characterized in that: The measuring of the compression change value of the target packaged battery cell under different pressure values ​​comprises the following steps: Placing the bottom surface of the target packaged battery cell on a workbench, and measuring the initial thickness value of the target packaged battery cell; Applying pressure to the front of the target packaged battery cell according to the set pressure value, and measuring the thickness value of the target packaged battery cell under different pressure values; According to the initial thickness value of the target packaged battery cell and the thickness values ​​under different pressure values, the compression amount change value of the target packaged battery cell under different pressure values ​​is determined.

3. A method for determining the preload force of a battery cell according to claim 2, characterized in that: The strain-pressure curve of the target packaged battery cell is drawn in the following manner: Draw a strain-pressure discrete point diagram according to the compression change value of the target packaged battery cell under different measured pressures; The discrete points in the strain-pressure discrete point diagram are fitted based on the least squares method to obtain the strain-pressure curve of the target packaged battery cell.

4. A method for determining the preload force of a battery cell according to claim 3, characterized in that: The elastic modulus is determined by the following formula: E=(F / S) / (dL / L0)=P / (dL / L0); Among them, F is the pressure applied to the front side of the target packaged battery cell; S is the area of ​​the front side of the target packaged battery cell; L0 is the initial thickness of the target packaged battery cell; dL is the change in thickness when pressure is applied to the front side of the target packaged battery cell.

5. A method for determining the preload force of a battery cell according to claim 4, characterized in that: After determining the pre-tightening force of the target packaged battery cell, it is verified whether the determined pre-tightening force of the target packaged battery cell is accurate.

6. A method for determining the preload force of a battery cell according to claim 5, characterized in that: Verify whether the preload force of the target packaged cell is accurate by: Obtaining the charge transfer resistance of the target packaged battery cell under different pressures; It is detected whether the charge transfer resistance of the target packaged battery cell under the pressure corresponding to the pre-tightening force is the smallest. If so, it is determined that the pre-tightening force of the target packaged battery cell is accurate.

7. A device for determining the preload force of a battery cell, characterized in that: The device comprises: A measuring module, used for selecting a target packaged battery cell and measuring a change in compression of the target packaged battery cell under different pressure values; A drawing module, used for drawing a strain-pressure curve of the target packaged battery cell according to the measured compression change value of the target packaged battery cell under different pressures; A determination module is used to analyze the drawn strain-pressure curve of the target packaged battery cell, determine the pressure value of the target packaged battery cell, and use it as the preload force of the target packaged battery cell; wherein, the elastic modulus of the target packaged battery cell is determined based on the strain-pressure curve of the target packaged battery cell; wherein, the elastic modulus is represented by the slope of the strain-pressure curve of the target packaged battery cell; if it is observed that the strain-pressure curve of the target packaged battery cell has a slope inflection point; the pressure value corresponding to the slope inflection point in the strain-pressure curve of the target packaged battery cell is used as the preload force of the target packaged battery cell.

8. An electronic device, characterized in that: include: A processor, a memory and a bus, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the processor and the memory communicate via the bus, and when the machine-readable instructions are executed by the processor, the steps of the method for determining the preload force of a battery cell as described in any one of claims 1 to 6 are performed.

9. A computer-readable storage medium, characterized in that: The computer readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for determining the preload force of a battery cell as claimed in any one of claims 1 to 6 are executed.

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