Battery detection method, production method, device, electronic device, storage medium, program product

Abstract

The present application discloses a battery detection method, a production method, a device, an electronic device, a storage medium, and a program product. Among them, the battery detection method includes: obtaining the expansion force data corresponding to each cycle during a preset number of cycles for the battery cell to be tested; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, determining the expansion force inflection point of the battery cell to be tested. The embodiments of the present application can solve the technical problem in the related art that the period required to obtain the expansion force inflection point of the battery cell is relatively long and it is difficult to meet the production cycle requirements of the battery.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and particularly to a battery detection method, a production method, a device, an electronic device, a storage medium, and a program product. Background Art

[0002] During the charging stage of a lithium-ion battery, due to factors such as the formation of the solid electrolyte interface (SEI) layer and the particle expansion caused by the intercalation of lithium into graphite, the swelling force of the battery cell will continuously increase; in practical applications, the swelling force inflection point is usually marked as the key point of significant change in the swelling behavior of the battery cell. After the swelling force reaches the swelling force inflection point, the growth rate of its swelling force will accelerate, which may lead to safety problems such as deformation or rupture of the battery housing.

[0003] In the related art, the maximum swelling force value in each charge-discharge cycle of the battery cell is usually obtained to draw the swelling force curve. Not only does this have a certain error from the true swelling force growth curve, but the cycle required to test to the swelling force inflection point is too long, making it difficult to meet the production cycle requirements of the battery.

[0004] The above statements are only used to provide background technical information related to the present application, and do not necessarily constitute prior art. Summary of the Invention

[0005] In view of the above problems, the present application provides a battery detection method, a production method, a device, an electronic device, a storage medium, and a program product, which can solve the technical problem that the cycle required to obtain the swelling force inflection point of the battery cell in the related art is relatively long and it is difficult to meet the production cycle requirements of the battery.

[0006] In a first aspect, the present application provides a battery detection method, including: obtaining the swelling force data corresponding to each cycle of a battery cell to be tested within a preset number of cycles; the swelling force data includes a first swelling force peak value and a second swelling force peak value corresponding to each charging process or each discharging process; determining the swelling force inflection point of the battery cell to be tested based on the first swelling force peak value and the second swelling force peak value corresponding to each charging process, or the first swelling force peak value and the second swelling force peak value corresponding to each discharging process.

[0007] In the technical solution of the embodiment of the present invention, by obtaining the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, the expansion force inflection point of the battery cell to be tested can be accurately determined. Compared with the method in the related art of determining the growth curve of the expansion force by only relying on the maximum expansion force value and further obtaining the expansion force inflection point of the battery cell, the present application can not only determine the growth trend of the expansion force by obtaining the expansion force peak values during the charging and discharging processes within a preset number of cycles, but also quickly determine the expansion force inflection point, greatly shortening the detection cycle of the battery cell, improving the production quality of the battery, with small limitations and high universality.

[0008] Determining the expansion force inflection point of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, includes: determining the target cycle number corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same, and the target cycle number includes a target charging cycle number or a target discharging cycle number; determining the expansion force inflection point of the battery cell to be tested according to the first expansion force peak value or the second expansion force peak value of the target cycle number.

[0009] In the embodiment of the present application, by analyzing the expansion force peak values within a preset number of cycles, determining the expansion force peak value corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same as the expansion force inflection point peak value corresponding to the battery cell, can quickly identify the expansion force inflection point of the battery cell, greatly shortening the detection cycle of the battery cell and improving the accuracy of the safety performance detection of the battery cell.

[0010] In some embodiments, the battery detection method further includes: obtaining the battery health corresponding to each cycle process of the battery cell to be tested within a preset number of cycles;

[0011] Determining the expansion force inflection point of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, includes: creating a first expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the first expansion force peak value during each cycle process; creating a second expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the second expansion force peak value during each cycle process; determining the intersection point of the first expansion force curve and the second expansion force curve as the expansion force inflection point corresponding to the battery cell to be tested.

[0012] In the embodiments of the present application, by combining the battery health as a reference parameter, the true state of the battery cell can be more accurately reflected. Combining the change trend of the battery health with the peak value of the swelling force can more precisely locate the swelling force inflection point corresponding to the battery cell to be tested. By using the above-mentioned first swelling force curve and the second swelling force curve to determine the swelling force inflection point corresponding to the battery cell to be tested, the visualization effect in the process of obtaining the swelling force inflection point can be significantly enhanced.

[0013] In some embodiments, before obtaining the battery health and swelling force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles, it includes: performing charge and discharge operations on the battery cell to be tested for a preset number of cycles based on a preset battery cell cycling strategy; wherein, the preset battery cell cycling strategy includes charging the battery cell to be tested to a first state of charge and discharging the battery cell to be tested to a second state of charge, and the first state of charge is greater than the second state of charge.

[0014] According to the preset cycling strategy in the embodiments of the present application, charging the battery cell to be tested to the first state of charge and discharging the battery cell to be tested to the second state of charge can complete multiple charge and discharge cycles in a short time, quickly obtain the health and swelling force data of the battery cell, thereby shortening the detection cycle and significantly improving the efficiency of battery charging.

[0015] In some embodiments, the first state of charge is the state of charge corresponding to full charge, and / or the second state of charge is the state of charge corresponding to full discharge. By performing cyclic tests in the full charge and near full discharge states to simulate the actual working conditions in the embodiments of the present application, the performance of the battery cell in actual use can be more realistically reflected. The change in the swelling force and the health state of the battery cell can be observed more quickly through tests under extreme working conditions, thereby improving the accuracy of battery cell detection.

[0016] In some embodiments, the performing charge and discharge operations on the battery cell to be tested for a preset number of cycles based on a preset battery cell cycling strategy includes: leaving the battery cell to be tested static for a first preset duration, performing constant current charging on the battery cell to be tested based on a first charging rate until the battery cell to be tested reaches the maximum charging voltage; performing constant voltage charging on the battery cell to be tested at the maximum charging voltage until the charging current drops to a second charging rate to make the battery cell to be tested reach the full charge state; leaving the battery cell to be tested static for a second preset duration, and discharging the battery cell to be tested based on a first discharge rate until the battery cell to be tested reaches the lowest voltage.

[0017] The embodiments of the present application simulate the actual usage scenarios of the battery cells. By simulating the charging and discharging processes in actual use, the performance of the battery cells in actual applications can be more realistically reflected. Conducting cyclic tests under fully charged and near fully discharged states can more significantly observe the changes in the swelling force and the health state of the battery cells, thereby improving the accuracy of battery cell detection. The polarization phenomenon is reduced through the static step, thereby ensuring the accuracy and reliability of the battery cell test data.

[0018] In some embodiments, the battery detection method further includes: based on the corresponding relationship between the battery health and the swelling force data for each cycle, determining the first health range corresponding to the battery cell to be tested when the rates of change of the first swelling force peak and the second swelling force peak both remain unchanged; based on the battery health and swelling force data within the first health range, determining the first swelling force fitting function corresponding to the battery cell to be tested; and based on the first swelling force fitting function, predicting the swelling force inflection point of the battery cell to be tested.

[0019] The embodiments of the present application, by determining the first health range corresponding to the battery cell to be tested when the rates of change of the first swelling force peak and the second swelling force peak both remain unchanged, further analyzing the relationship between the battery health and the swelling force data within this first health range, and establishing a fitting function, can more accurately capture the initial trend of the increase in the swelling force of the battery cell, thereby improving the accuracy of predicting the swelling force inflection point and reducing the error caused by relying solely on experimental data.

[0020] In some embodiments, the first health range is the health range of the battery cell to be tested before reaching the swelling force inflection point. The embodiments of the present application, by analyzing the relationship between the health and the swelling force data and establishing a fitting function, can accurately predict the swelling force inflection point of the battery cell without having to test up to the swelling force inflection point, and can also reduce the error caused by relying solely on experimental data.

[0021] In some embodiments, the above battery detection method further includes: based on the corresponding relationship between the battery health and the swelling force data for each cycle, and the battery health and swelling force data of the battery cell to be tested within the second health range, determining the second swelling force fitting function corresponding to the battery cell to be tested; wherein the second health range is the health range of the battery cell after reaching the swelling force inflection point; and based on the second swelling force fitting function, predicting the swelling force value of the battery cell to be tested.

[0022] In the embodiment of the present application, by determining the second health degree range after the battery cell reaches the inflection point of the expansion force, further analyzing the relationship between the battery health degree and the expansion force data within the first health degree range, and establishing a fitting function, the growth trend of the expansion force of the battery cell after the inflection point of the expansion force can be captured more accurately, significantly improving the accuracy of the expansion force prediction and reducing the error caused by relying solely on experimental data.

[0023] In some embodiments, the above battery detection method further includes: determining the termination health degree corresponding to the battery cell to be tested in the case of reaching the end-of-life state; based on the second expansion force fitting function, determining the target expansion force value corresponding to the termination health degree; and determining whether an abnormality occurs during the use of the battery cell to be tested based on the target expansion force value. The fitting function combining the health degree and the expansion force data in the present application can more accurately predict the end-of-life state of the battery cell. By predicting the target expansion force value corresponding to the termination health degree, early warning can be given when an abnormality occurs before the battery cell reaches the end-of-life state, reducing potential safety problems of the battery cell.

[0024] In a second aspect, an embodiment of the present invention provides a battery production method, including the battery detection method as described in the first aspect.

[0025] In a third aspect, an embodiment of the present invention provides a battery detection device, including: an acquisition unit for acquiring the expansion force data corresponding to each cycle during a preset number of cycles of the battery cell to be tested; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; and a first determination unit for determining the inflection point of the expansion force of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process.

[0026] In a fourth aspect, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the battery detection method as described in the first aspect is implemented.

[0027] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium storing a computer program, and when the computer program is executed by a processor, the battery detection method as described in the first aspect is implemented.

[0028] In a sixth aspect, an embodiment of the present application further provides a computer program product, including a computer program, characterized in that the computer program is executed by a processor to implement the battery detection method as described in the first aspect.

[0029] The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically exemplified below. Description of the Drawings

[0030] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0031] Figure 1 is a flowchart of a battery detection method provided according to an embodiment of the present application;

[0032] Figure 2 is a flowchart of another battery detection method provided according to an embodiment of the present application;

[0033] Figure 3 is a flowchart of yet another battery detection method provided according to an embodiment of the present application;

[0034] Figure 4 is a schematic structural diagram of a battery expansion force detection device provided according to an embodiment of the present application;

[0035] Figure 5 is a schematic diagram of the expansion force - SOC curve of a battery provided according to an embodiment of the present application;

[0036] Figure 6 is a schematic diagram of an expansion force curve provided according to an embodiment of the present application;

[0037] Figure 7 is another schematic diagram of an expansion force curve provided according to an embodiment of the present application;

[0038] Figure 8 is a schematic structural diagram of a battery detection device provided according to an embodiment of the present application;

[0039] Figure 9 is a schematic structural diagram of an electronic device provided according to an embodiment of the present application. Detailed Embodiments

[0040] The embodiments of the technical solution of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0042] In the description of the embodiments of the present invention, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "a plurality of" is more than two, unless otherwise specifically defined.

[0043] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0044] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0045] In the description of the embodiments of the present invention, the term "a plurality of" refers to more than two (including two). Similarly, "a plurality of groups" refers to more than two groups (including two groups), and "a plurality of pieces" refers to more than two pieces (including two pieces).

[0046] Currently, the application of power batteries is becoming more and more extensive. Power batteries are not only applied to energy storage power systems such as hydraulic, thermal, wind, and solar power stations, but also widely used in electric transportation such as electric bicycles, electric motorcycles, and electric vehicles, as well as in multiple fields such as military equipment and aerospace. In fields such as electric transportation supply, military equipment, and aerospace, power is usually provided by batteries.

[0047] Among various types of power batteries, due to the advantages of high power density, high energy density, long cycle life, high output voltage, and environmental friendliness of lithium batteries, they are widely used in fields such as new energy vehicles, consumer electronics, and energy storage systems. How to improve the charging speed of lithium batteries while ensuring charging performance has become a current research hotspot.

[0048] As the degree of cycle aging (or storage aging) of a lithium battery increases, a process of destruction / repair of the solid electrolyte interface (SEI) layer occurs inside the battery. The SEI layer thickens, and the positive and negative electrode plates rebound, all of which increase the swelling force of the lithium battery cell. When this increase in swelling force reaches a certain range, it will affect the structure of the battery module, such as safety hazards like a decrease in battery performance, rupture of the battery case, leakage of the electrolyte, and internal short circuit of the battery. Due to possible abnormalities in the incoming materials, abnormal water content in the environment, and abnormal production process parameters during the production process, the swelling force of the battery cell of the battery product may exceed the safety range.

[0049] During the charging stage of a lithium-ion battery, due to factors such as the formation of the solid electrolyte interface (SEI) layer and the particle swelling caused by lithium intercalation into graphite, the swelling force of the battery cell will continuously increase. In practical applications, the swelling force inflection point is usually marked as a key point with a significant change in the swelling behavior of the battery cell. After the swelling force reaches the swelling force inflection point, the growth rate of its swelling force will accelerate, which may lead to safety problems such as deformation or rupture of the battery case.

[0050] In related technologies, the maximum swelling force value during each charge-discharge cycle of the battery cell is usually obtained to plot the swelling force curve. Not only is there a certain error from the actual swelling force growth curve, but the cycle required to test to the swelling force inflection point is too long, making it difficult to meet the production cycle requirements of the battery.

[0051] Based on the above problems existing in related technologies, the present application proposes a battery detection method, device, electronic device, and storage medium. The battery detection method includes: obtaining the swelling force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles; the swelling force data includes a first swelling force peak value and a second swelling force peak value corresponding to each charging process or each discharging process; based on the first swelling force peak value and the second swelling force peak value corresponding to each charging process, or the first swelling force peak value and the second swelling force peak value corresponding to each discharging process, determine the swelling force inflection point of the battery cell to be tested.

[0052] In the technical solution of the embodiment of the present invention, by obtaining the swelling force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles; the swelling force data includes a first swelling force peak value and a second swelling force peak value corresponding to each charging process or each discharging process; based on the first swelling force peak value and the second swelling force peak value, the swelling force inflection point of the battery cell to be tested can be accurately determined. Compared with the method of further obtaining the swelling force inflection point of the battery cell by only relying on the maximum swelling force value to determine the growth curve of the swelling force in the related art, the present application can not only determine the growth trend of the swelling force of the battery cell by obtaining the swelling force peak values during the charging and discharging processes within the preset number of cycles, but also quickly determine the swelling force inflection point, greatly shortening the battery cell detection cycle, improving the production quality of the battery, with small limitations and high universality.

[0053] The following specifically describes the specific process of the battery detection method of the present application through specific embodiments. Refer to Figure 1 the flowchart of the battery detection method shown in the figure, and the method specifically includes the following steps:

[0054] S102, obtaining the swelling force data corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; the swelling force data includes a first swelling force peak value and a second swelling force peak value corresponding to each charging process or each discharging process;

[0055] S104, determining the swelling force inflection point of the battery cell to be tested based on the first swelling force peak value and the second swelling force peak value corresponding to each charging process, or the first swelling force peak value and the second swelling force peak value corresponding to each discharging process.

[0056] Specifically, in the embodiment of the present invention, the above-mentioned battery cell type can be, for example, a ternary lithium battery cell or a lithium iron phosphate battery cell. The above-mentioned preset number of cycles can be adjusted according to actual R & D or production needs. For example, for mass production sampling battery cells, more than 100 cycles are required, and for the battery cells involved in the R & D process, more than 500 cycles are required. In order to obtain the swelling force of each battery cell to be tested during the battery production process, it is necessary to monitor the swelling force of the battery cell during the production process by using a fixture for the battery cell. As Figure 4 shown, the embodiment of the present application can use, for example, three steel fixtures 402 and two fixing members 404 to fix the battery cell to be tested 408 and the pressure sensor 406. The battery cell to be tested 408 and the pressure sensor 406 are respectively located between two steel fixtures 402, and the output value of the pressure sensor is obtained to monitor the swelling force value during the battery cell test process. Based on the above method, the swelling force values corresponding to different states of charge (SOC) of each battery cell during the cycle process can be obtained.

[0057] During the charging or discharging stage of a lithium-ion battery, factors such as the formation of the SEI layer and particle expansion caused by lithium intercalation into graphite can cause changes in the swelling force of the battery cell; combined with Figure 5 As shown in

[0058] In one example, for instance, obtain the first swelling force peak and the second swelling force peak corresponding to each charging process, as well as the first swelling force peak and the second swelling force peak corresponding to each discharging process, within 200 cycles of the battery cell to be tested; that is, the first swelling force peak and the second swelling force peak corresponding to 200 charging processes, and the first swelling force peak and the second swelling force peak corresponding to 200 discharging processes can be obtained. During one cycle, the first swelling force peak corresponding to the discharging process is less than or equal to the first swelling force peak corresponding to the charging process, and the second swelling force peak corresponding to the discharging process is less than or equal to the second swelling force peak corresponding to the charging process.

[0059] Based on the first swelling force peak and the second swelling force peak during the above-mentioned charging or discharging process, the present application can accurately determine the swelling force inflection point of the battery cell to be tested.

[0060] In the technical solution of the embodiment of the present invention, by obtaining the swelling force data corresponding to each cycle within a preset number of cycles of the battery cell to be tested; the swelling force data includes the first swelling force peak and the second swelling force peak corresponding to each charging process or each discharging process; based on the first swelling force peak and the second swelling force peak, the swelling force inflection point of the battery cell to be tested can be accurately determined. Compared with the method in the related art of further obtaining the swelling force inflection point by only relying on the maximum swelling force value to determine the growth curve of the swelling force, the present application can not only determine the growth trend of the swelling force of the battery cell by obtaining the swelling force peaks during the charging and discharging processes within a preset number of cycles, but also quickly determine the swelling force inflection point, greatly shortening the detection cycle of the battery cell, improving the production quality of the battery, with small limitations and high universality.

[0061] In one or more embodiments of the present application, as Figure 2 shown, the above battery detection method includes the following steps:

[0062] S102, obtain the swelling force data corresponding to each cycle within a preset number of cycles of the battery cell to be tested; the swelling force data includes the first swelling force peak and the second swelling force peak corresponding to each charging process or each discharging process;

[0063] S204. Determine the target cycle number corresponding to the same first swelling force peak value and second swelling force peak value, where the target cycle number includes a target charging cycle number or a target discharging cycle number.

[0064] S206. Determine the swelling force inflection point of the battery cell to be tested according to the first swelling force peak value or the second swelling force peak value of the target cycle number.

[0065] Specifically, in the embodiments of the present invention, by analyzing the first swelling force peak value and the second swelling force peak value corresponding to each charging cycle number and each discharging cycle number within a preset number of cycles; determine whether the first swelling force peak value and the second swelling force peak value in each charging cycle number or each discharging cycle number are the same; it should be noted that the target cycle number in the embodiments of the present application may be the cycle number in which the first swelling force peak value and the second swelling force peak value are equal in a charging cycle number or a discharging cycle number.

[0066] In an example, for example, determine the cycle number corresponding to the charging cycle number when the first swelling force peak value and the second swelling force peak value are the same as the target cycle number. This charging cycle number is the critical point at which the swelling force of the battery cell to be tested changes significantly. Then, determine the swelling force inflection point of the battery cell to be tested according to the first swelling force peak value or the second swelling force peak value of the charging cycle number (target cycle number).

[0067] The above step S102 has been described above and will not be repeated here.

[0068] In the embodiments of the present application, by analyzing the swelling force peak values within a preset number of cycles, determine the swelling force peak value corresponding to the same first swelling force peak value and second swelling force peak value as the swelling force inflection point peak value of the battery cell, which can quickly identify the swelling force inflection point of the battery cell, greatly shorten the battery cell detection period, and improve the accuracy of the battery cell safety performance detection.

[0069] In one or more embodiments of the present application, as Figure 3 shown, the above battery detection method includes the following steps:

[0070] S102. Obtain the swelling force data corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; the swelling force data includes the first swelling force peak value and the second swelling force peak value corresponding to each charging process or each discharging process.

[0071] S304. Obtain the battery health degree corresponding to each cycle process of the battery cell to be tested within a preset number of cycles.

[0072] S306. Create the first swelling force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health degree and the first swelling force peak value in each cycle process.

[0073] S308. Create a second expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the second peak expansion force during each cycle.

[0074] S310. Determine the intersection point of the first expansion force curve and the second expansion force curve as the expansion force inflection point corresponding to the battery cell to be tested.

[0075] Specifically, in the embodiment of the present application, within a preset number of cycles, record the battery health (State of Health, SOH) corresponding to each cycle. In one example, the battery health corresponding to each cycle above can be the SOH corresponding to each charging process or the SOH corresponding to each discharging process. Here, the battery health can be evaluated through the capacity retention rate, internal resistance change or other performance indicators of the battery cell.

[0076] As Figure 6 shown, create a first expansion force curve according to the corresponding relationship between the battery health and the first peak expansion force during each cycle. This first expansion force curve reflects the change trend of the peak expansion force of the battery cell during the charging process with respect to the health. Create a second expansion force curve according to the corresponding relationship between the battery health and the second peak expansion force during each cycle. This second expansion force curve reflects the change trend of the peak expansion force of the battery cell during the charging process with respect to the health. Determine the intersection point (point P) of the first expansion force curve and the second expansion force curve as the expansion force inflection point corresponding to the battery cell. The expansion force inflection point is the point where the growth rate of the battery cell's expansion force changes significantly, that is, the change in the internal structure of the battery cell or potential health problems.

[0077] Due to the certain buffering effect between the initial bare battery cell (Jelly - Roll, abbreviated as JR) and the outer packaging aluminum shell, the bare battery cell needs to consume approximately 3% of the active lithium to reach the fully top - shell state. Therefore, the increase in the first peak expansion force and the second peak expansion force is not obvious in the SOH interval of 100% - 97%. After the JR reaches the fully top - shell state, both the first peak expansion force and the second peak expansion force increase linearly. The intersection point (point P) of the first expansion force curve and the second expansion force curve is the inflection point of the expansion force curve corresponding to the battery cell.

[0078] The above step S102 has been described previously and will not be elaborated here.

[0079] In the embodiments of the present application, by combining the battery health as a reference parameter, the true state of the battery cell can be more accurately reflected. Combining the change trend of the battery health with the peak value of the swelling force can more precisely locate the swelling force inflection point corresponding to the battery cell to be tested. Determining the swelling force inflection point corresponding to the battery cell to be tested through the above-mentioned first swelling force curve and the second swelling force curve can significantly enhance the visualization effect in the process of obtaining the swelling force inflection point.

[0080] In one or more embodiments, before obtaining the battery health and swelling force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles, it includes:

[0081] Based on a preset battery cell cycling strategy, perform charge and discharge operations on the battery cell to be tested for a preset number of cycles; wherein, the preset battery cell cycling strategy includes charging the battery cell to a first state of charge and discharging the battery cell to a second state of charge, and the first state of charge is greater than the second state of charge.

[0082] Specifically, in the embodiments of the present application, before obtaining the health and swelling force data of the battery cell to be tested, charge and discharge operations need to be performed according to a preset battery cell cycling strategy. For example, during the charging process of each cycle, the battery cell to be tested is charged to a first state of charge. The value range of the above-mentioned first state of charge can be, for example, [95%, 100%] SOC, and the value range of the above-mentioned second state of charge can be, for example, [5%, 10%] SOC to simulate the extreme working conditions of the battery cell in actual use. The battery cell cycling strategy in the present application can ensure that the battery cell experiences a complete charge and discharge working condition during the test, thereby providing a comprehensive and accurate reference for the subsequent prediction of the swelling force inflection point of the battery cell.

[0083] According to the preset cycling strategy in the embodiments of the present application, charging the battery cell to be tested to a first state of charge and discharging the battery cell to be tested to a second state of charge can complete multiple charge and discharge cycles in a short time, quickly obtain the health and swelling force data of the battery cell, thereby shortening the detection cycle and significantly improving the efficiency of battery charging.

[0084] In one or more embodiments, the first state of charge is the state of charge corresponding to full charge, and / or the second state of charge is the state of charge corresponding to full discharge.

[0085] By performing cyclic tests in the full charge and near full discharge states to simulate the actual working conditions in the embodiments of the present application, the performance of the battery cell in actual use can be more realistically reflected. Through tests under extreme working conditions, the swelling force change and health state of the battery cell can be obtained more quickly, thereby improving the accuracy of battery cell detection.

[0086] In one or more embodiments, performing charge and discharge operations on the cell under test for a preset number of cycles based on a preset cell cycling strategy includes:

[0087] Let the cell under test stand for a first preset duration, and perform constant current charging on the cell under test based on a first charging rate until the cell under test reaches the maximum charging voltage;

[0088] Perform constant voltage charging on the cell under test at the maximum charging voltage until the charging current drops to a second charging rate to make the cell under test reach a fully charged state;

[0089] Let the cell under test stand for a second preset duration, and discharge the cell under test based on a first discharge rate until the cell under test reaches the lowest voltage.

[0090] Specifically, the value range of the above first preset duration can be, for example, [5 - 15] minutes, the value range of the above second preset duration can be [5 - 15] minutes, the above first charging rate can be 1C. The above second charging rate can be 0.05C. For example, for a 1000 mAh battery, the current corresponding to 0.05C is 50 mA, the maximum charging voltage Vmax of the lithium-ion battery is 4.2V, and the lowest voltage Vmin is 2.5V.

[0091] In an example, the charge and discharge test process adopted in this application includes:

[0092] 1) Rest 10 min (stand for 10 minutes); Let the battery reach a chemical equilibrium state before the test, reduce the polarization effect, and ensure the accuracy of subsequent tests.

[0093] 2) 1C CC Vmax (perform constant current charging at 1C until the battery voltage reaches the maximum voltage Vmax);

[0094] 3) Vmax CV 0.05C (when the battery voltage reaches Vmax, switch to the constant voltage charging mode until the charging current drops to 0.05C);

[0095] 4) Rest 10 min (stand for 10 minutes); Let the battery reach a chemical equilibrium state after charging, reduce the polarization effect, and ensure the accuracy of subsequent discharge tests.

[0096] 5) 1C DC Vmin (perform constant current discharge at 1C until the battery voltage drops to the lowest voltage Vmin);

[0097] 6) Repeat steps 1) to 5) for a total of x times; Among them, for mass production sampled cells, the value of x is greater than or equal to 100; for R & D cells, the value of x is greater than or equal to 500.

[0098] The embodiments of the present application simulate the actual usage scenarios of the battery cells. By simulating the charging and discharging processes in actual use, the performance of the battery cells in actual applications can be more realistically reflected. Conducting cycle tests in the fully charged and near fully discharged states can more significantly observe the changes in the swelling force and the health state of the battery cells, thereby improving the accuracy of battery cell detection. The polarization phenomenon is reduced through the static step, ensuring the accuracy and reliability of the battery cell test data.

[0099] In one or more embodiments, the battery detection method further includes:

[0100] Based on the correspondence relationship between the battery health and the swelling force data for each cycle, determine the first health range corresponding to the battery cell to be tested when the rates of change of the first swelling force peak and the second swelling force peak both remain unchanged.

[0101] Based on the battery health and swelling force data within the first health range, determine the first swelling force fitting function corresponding to the battery cell to be tested.

[0102] Based on the first swelling force fitting function, predict the swelling force inflection point of the battery cell to be tested.

[0103] Since after JR reaches the fully top-shell state, both the first swelling force peak and the second swelling force peak increase linearly. In the embodiments of the present application, by analyzing the rates of change of the first swelling force peak and the second swelling force peak, find the interval where the rate of change remains stable, and determine the health range corresponding to this interval as the first health range. Select a suitable mathematical model (such as a linear or non-linear regression model).

[0104] Use the data within the first health range to fit the model to obtain the first swelling force fitting function. This function can describe the trend of the swelling force changing with the health. The first swelling force fitting function includes the fitting function corresponding to the first swelling force peak and the fitting function corresponding to the second swelling force peak.

[0105] In the embodiments of the present application, by determining the first health range corresponding to the battery cell to be tested when the rates of change of the first swelling force peak and the second swelling force peak both remain unchanged, further analyzing the relationship between the battery health and the swelling force data within this first health range, and establishing a fitting function, the initial trend of the increase in the swelling force of the battery cell can be more accurately captured, thereby improving the accuracy of predicting the swelling force inflection point and reducing the error caused by relying solely on experimental data.

[0106] In one or more embodiments, the first health range is the health range of the battery cell to be tested before reaching the swelling force inflection point.

[0107] In the embodiments of the present application, it is not necessary to test the inflection point of the swelling force. It is only necessary to test 1% loss of active lithium after JR reaches the top case, that is, according to the linear part of 95% - 96% loss of active lithium (the battery health is in the range of 95% - 96%), a fitting operation is performed on the linear part. In one example, as Figure 7 shown, based on the first swelling force curve, the fitting function corresponding to the first swelling force peak is: y = -5088.1x + 5075.3; based on the second swelling force curve, the fitting function corresponding to the second swelling force peak is: y = -4091.8x + 4159.3; where y represents the actual swelling force value and x represents the battery health. By solving according to the above two fitting functions, the predicted swelling force inflection point value is: 91.931% SOH.

[0108] The embodiments of the application analyze the relationship between the health and the swelling force data, establish a fitting function, and can accurately predict the swelling force inflection point of the battery cell without testing the swelling force inflection point, and can also reduce the error caused by relying solely on experimental data.

[0109] In one or more embodiments, the battery detection method further includes:

[0110] Based on the corresponding relationship between the battery health and the swelling force data of each cycle, and the battery health and the swelling force data of the battery cell to be tested within the second health range, determine the second swelling force fitting function corresponding to the battery cell to be tested; where the second health range is the health range of the battery cell after reaching the swelling force inflection point;

[0111] Predict the swelling force value of the battery cell to be tested based on the second swelling force fitting function.

[0112] Specifically, in the embodiments of the present application, obtain the health and the swelling force data of the battery cell to be tested within the second health range, determine the corresponding mathematical model according to the characteristics of the health and the swelling force data within this range, and determine the parameters of the fitting function through regression analysis or model optimization methods, so that the model can accurately describe the change of the swelling force with the health.

[0113] In one example, by using a linear model for prediction, the prediction function is: F = k*(1 - SOH) + b, where F is the swelling force value, SOH is the health state of the battery, and k and b are the relevant parameters output by the model,

[0114] In the embodiment of the present application, by determining the second health degree range after the battery cell reaches the inflection point of the expansion force, further analyzing the relationship between the battery health degree and the expansion force data within the first health degree range, and establishing a fitting function, the growth trend of the expansion force of the battery cell after the inflection point of the expansion force can be captured more accurately, significantly improving the accuracy of the expansion force prediction and reducing the error caused by relying solely on experimental data.

[0115] In one or more embodiments, the battery detection method further includes:

[0116] Determining the termination health degree corresponding to the battery cell to be tested when reaching the end-of-life state;

[0117] Based on the second expansion force fitting function, determining the target expansion force value corresponding to the termination health degree;

[0118] Based on the target expansion force value, determining whether the battery cell to be tested has an abnormality during use.

[0119] Specifically, in the embodiment of the present application, assuming that the termination health degree corresponding to the battery cell to be tested is 60%, substituting the termination health degree of 60% into the second expansion force fitting function to calculate the corresponding target expansion force value. If the expansion force value corresponding to the battery cell to be tested during use is greater than or equal to the target expansion force value, it indicates that the battery cell to be tested has an abnormal situation at this time; on the contrary, if the expansion force value corresponding to the battery cell to be tested is less than the target expansion force value, it indicates that the battery cell to be tested has no abnormality at this time.

[0120] The fitting function combining the health degree and the expansion force data in the present application can more accurately predict the end-of-life state of the battery cell. By predicting the target expansion force value corresponding to the termination health degree, early warning can be carried out when an abnormality occurs before the battery cell reaches the end-of-life state, reducing potential safety problems of the battery cell.

[0121] In one or more embodiments of the present application, the present application further provides a battery production method, which includes the steps of the battery detection method in the above embodiments. Specifically, the present application can integrate or apply the above battery detection method in the battery production process, such as sampling the mass-produced battery cells. In one example, the above battery detection method can also be applied to the R & D process of the battery.

[0122] The embodiment of the present invention further provides a battery detection device, which is used to execute the battery detection method provided in the above embodiments, such as Figure 8 shown, the device includes:

[0123] The first acquisition unit 802 is configured to acquire the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process.

[0124] The first determination unit 804 is configured to determine the expansion force inflection point of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process.

[0125] In the technical solution of the embodiment of the present invention, by acquiring the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; based on the first expansion force peak value and the second expansion force peak value, the expansion force inflection point of the battery cell to be tested can be accurately determined. Compared with the related art in which the growth curve of the expansion force is determined only by relying on the maximum expansion force value and further obtaining the expansion force inflection point, the present application can not only determine the growth trend of the expansion force by acquiring the expansion force peak values during the charging and discharging processes within the preset number of cycles, but also quickly determine the expansion force inflection point, greatly shortening the battery cell detection cycle, improving the production quality of the battery, with small limitations and high universality.

[0126] In one or more embodiments of the present application, the first determination unit 804 includes:

[0127] The first determination module is configured to determine the target cycle number corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same, and the target cycle number includes a target charging cycle number or a target discharging cycle number.

[0128] The second determination module is configured to determine the expansion force inflection point of the battery cell to be tested according to the first expansion force peak value or the second expansion force peak value of the target cycle number.

[0129] In one or more embodiments of the present application, the above battery detection device further includes: a second acquisition unit configured to acquire the battery health corresponding to each cycle of the battery cell to be tested within a preset number of cycles.

[0130] The first determination unit 804 includes:

[0131] The first creation module is configured to create a first expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the first expansion force peak value during each cycle process.

[0132] A second creation module, configured to create a second expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the second peak expansion force during each cycle;

[0133] A third determination module, configured to determine the intersection point of the first expansion force curve and the second expansion force curve as the expansion force inflection point corresponding to the battery cell to be tested.

[0134] In one or more embodiments of the present application, the above battery detection device further includes:

[0135] A charge and discharge unit, configured to perform charge and discharge operations on the battery cell to be tested for a preset number of cycles based on a preset battery cell cycling strategy; wherein, the preset battery cell cycling strategy includes charging the battery cell to be tested to a first state of charge and discharging the battery cell to be tested to a second state of charge, and the first state of charge is greater than the second state of charge.

[0136] In one or more embodiments of the present application, the first state of charge is the state of charge corresponding to full charge, and / or, the second state of charge is the state of charge corresponding to full discharge.

[0137] In one or more embodiments of the present application, the charge and discharge unit includes:

[0138] A static charging module, configured to statically charge the battery cell to be tested for a first preset duration and perform constant current charging on the battery cell to be tested based on a first charging rate until the battery cell to be tested reaches the maximum charging voltage;

[0139] A charging module, configured to perform constant voltage charging on the battery cell to be tested at the maximum charging voltage until the charging current drops to a second charging rate to make the battery cell to be tested reach the full charge state;

[0140] A static discharging module, configured to statically discharge the battery cell to be tested for a second preset duration and discharge the battery cell to be tested based on a first discharging rate until the battery cell to be tested reaches the lowest voltage.

[0141] In one or more embodiments of the present application, the above battery detection device further includes:

[0142] A second determination unit, configured to determine a first health range corresponding to the battery cell to be tested when the rates of change of the first peak expansion force and the second peak expansion force both remain unchanged based on the corresponding relationship between the battery health and the expansion force data for each cycle;

[0143] A third determination unit, configured to determine a first expansion force fitting function corresponding to the battery cell to be tested based on the battery health and expansion force data within the first health range;

[0144] A first prediction unit, configured to predict an expansion force inflection point of the battery cell to be measured based on the first expansion force fitting function.

[0145] In one or more embodiments of the present application, the first state of health range is the state of health range of the battery cell to be measured before reaching the expansion force inflection point.

[0146] In one or more embodiments of the present application, the above battery detection device further includes:

[0147] A fourth determination unit, configured to determine a second expansion force fitting function corresponding to the battery cell to be measured based on the corresponding relationship, and the battery state of health and expansion force data of the battery cell to be measured within a second state of health range; wherein, the second state of health range is the state of health range of the battery cell to be measured after reaching the expansion force inflection point;

[0148] A second prediction unit, configured to predict an expansion force value of the battery cell to be measured based on the second expansion force fitting function.

[0149] In one or more embodiments of the present application, the above battery detection device further includes:

[0150] A fifth determination unit, configured to determine a termination state of health corresponding to the battery cell to be measured when reaching the end-of-life state;

[0151] A sixth determination unit, configured to determine a target expansion force value corresponding to the termination state of health based on the second expansion force fitting function;

[0152] A seventh determination unit, configured to determine whether an abnormality occurs in the battery cell to be measured during use based on the target expansion force value.

[0153] Figure 9 It is a logical structure block diagram of an electronic device shown according to an exemplary embodiment. For example, the electronic device 900 may be an electronic device such as a BMS, a vehicle-mounted controller, a motor controller, or a domain controller disposed inside an electrical device.

[0154] In an exemplary embodiment, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions, and the instructions can be executed by a battery processor to complete the above battery detection method. The method includes: obtaining expansion force data corresponding to each cycle of a battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, determining an expansion force inflection point of the battery cell to be tested. Optionally, the above instructions can also be executed by a processor of the battery to complete other steps involved in the above exemplary embodiment. For example, the non-transitory computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0155] In an exemplary embodiment, an application program / computer program product is also provided, including one or more instructions, and the one or more instructions can be executed by a processor of a battery to complete the above battery detection method. The method includes: obtaining expansion force data corresponding to each cycle of a battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, determining an expansion force inflection point of the battery cell to be tested. Optionally, the above instructions can also be executed by a processor of the battery to complete other steps involved in the above exemplary embodiment. Figure 9 FIG. 900 is an example diagram of an electronic device. Those skilled in the art can understand that the schematic Figure 9 is merely an example of the electronic device 900, and does not constitute a limitation on the electronic device 900. It may include more or fewer components than those shown in the figure, or combine certain components, or different components. For example, the electronic device 900 may also include input / output devices, network access devices, a bus, etc.

[0156] The so-called processor 902 may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor, or the processor 902 may also be any conventional processor, etc. The processor 902 is the control center of the electronic device 900, and connects various parts of the entire electronic device 900 through various interfaces and lines.

[0157] The memory 901 can be used to store computer-readable instructions. The processor 902 realizes various functions of the electronic device 900 by running or executing the computer-readable instructions or modules stored in the memory 901, and by calling the data stored in the memory 901. The memory 901 may mainly include a program storage area and a data storage area. Among them, the program storage area may store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area may store data created according to the use of the electronic device 900. In addition, the memory 901 may include a hard disk, memory, plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, at least one magnetic disk storage device, flash memory device, Read-Only Memory (ROM), Random Access Memory (RAM), or other non-volatile / volatile storage devices.

[0158] If the modules integrated in the electronic device 900 are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above-mentioned embodiment methods of the present invention, computer-readable instructions can also be used to instruct relevant hardware to complete. The computer-readable instructions can be stored in a computer-readable storage medium. When the computer-readable instructions are executed by the processor, the steps of the above-mentioned various method embodiments can be implemented.

[0159] Other embodiments of the present application will be readily contemplated by those skilled in the art after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application that follow the general principles of the present application and include well-known knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only illustrative, and the true scope and spirit of the present application are pointed out by the following claims.

[0160] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

[0161] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in the present application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant laws, regulations, and standards of relevant countries and regions, and corresponding operation entrances are provided for users to choose to authorize or refuse.

Claims

1. A battery detection method, characterized in that: include: Obtaining expansion force data corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; Based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, determining the expansion force inflection point of the battery cell to be tested, including: determining a target cycle round corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same, the target cycle round including a target charging round or a target discharging round; determining the expansion force inflection point of the battery cell to be tested according to the first expansion force peak value or the second expansion force peak value of the target cycle round.

2. The method according to claim 1, characterized in that The method further includes: obtaining the battery health corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; The step of determining the expansion force inflection point of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, comprises: Creating a first expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the first expansion force peak value during each cycle; Creating a second expansion force curve corresponding to the battery cell to be tested according to the corresponding relationship between the battery health and the second expansion force peak value during each cycle; The intersection point of the first expansion force curve and the second expansion force curve is determined as the expansion force inflection point corresponding to the battery cell to be tested.

3. The method according to any one of claims 1 to 2, characterized in that: Before obtaining the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles, the method includes: Based on a preset battery cell cycling strategy, the battery cell to be tested is subjected to a preset number of charge and discharge operations; wherein the preset battery cell cycling strategy includes charging the battery cell to be tested to a first state of charge, and discharging the battery cell to be tested to a second state of charge, wherein the first state of charge is greater than the second state of charge.

4. The method according to claim 3, characterized in that The first state of charge is a state of charge corresponding to full charge, and / or the second state of charge is a state of charge corresponding to full discharge.

5. The method according to claim 3, characterized in that: The method of performing a preset number of charge and discharge operations on the battery cell to be tested based on a preset battery cell cycle strategy includes: The battery cell to be tested is left to stand for a first preset time, and the battery cell to be tested is charged with a constant current based on a first charging rate until the battery cell to be tested reaches a maximum charging voltage; The battery cell to be tested is charged at a constant voltage at the maximum charging voltage until the charging current drops to a second charging rate, so that the battery cell to be tested reaches a fully charged state; The battery cell to be tested is left to stand for a second preset time period, and the battery cell to be tested is discharged based on a first discharge rate until the battery cell to be tested reaches a minimum voltage.

6. The method according to any one of claims 1 to 2, characterized in that: The method further comprises: Based on the correspondence between the battery health and the expansion force data of each cycle, determining a first health range corresponding to the battery cell to be tested when the rate of change of the first expansion force peak value and the rate of change of the second expansion force peak value remain unchanged; Determine a first expansion force fitting function corresponding to the battery cell to be tested based on the battery health and expansion force data within a first health range; Based on the first expansion force fitting function, an expansion force inflection point of the battery cell to be tested is predicted.

7. The method according to claim 6, characterized in that The first health range is the health range of the battery cell to be tested before it reaches the expansion force inflection point.

8. The method according to claim 6, characterized in that The method further comprises: Based on the correspondence between the battery health and the expansion force data of each cycle, and the battery health and expansion force data of the battery cell to be tested within a second health range, determine a second expansion force fitting function corresponding to the battery cell to be tested; wherein the second health range is a health range after the battery cell to be tested reaches the expansion force inflection point; The expansion force value of the battery cell to be tested is predicted based on the second expansion force fitting function.

9. The method according to claim 8, characterized in that The method further comprises: Determine the termination health corresponding to the battery cell to be tested when reaching the end-of-life state; Determining a target expansion force value corresponding to the termination health degree based on a second expansion force fitting function; Whether an abnormality occurs to the battery cell to be tested during use is determined based on the target expansion force value.

10. A battery production method, characterized in that: The invention comprises a battery detection method as described in any one of claims 1 to 9.

11. A battery detection device, characterized in that: include: An acquisition unit, used to acquire expansion force data corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; the expansion force data includes a first expansion force peak value and a second expansion force peak value corresponding to each charging process or each discharging process; The first determination unit is used to determine the expansion force inflection point of the battery cell to be tested based on the first expansion force peak value and the second expansion force peak value corresponding to each charging process, or the first expansion force peak value and the second expansion force peak value corresponding to each discharging process, including: determining a target cycle round corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same, the target cycle round including a target charging round or a target discharging round; determining the expansion force inflection point of the battery cell to be tested according to the first expansion force peak value or the second expansion force peak value of the target cycle round.

12. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to execute the method according to any one of claims 1 to 10 through the computer program.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored program, wherein the program executes the method described in any one of claims 1 to 10 when executed.

14. A computer program product comprising a computer program, characterized in that The computer program is executed by a processor to implement the method according to any one of claims 1 to 10.

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