Battery detection method, battery production method, battery production device, electronic equipment, storage medium and program product

Abstract

The invention discloses a battery detection method, a battery production method, a battery production device, electronic equipment, a storage medium and a program product. The battery detection method comprises the following steps: acquiring expansive force data corresponding to each cycle process of a to-be-detected battery cell within a preset cycle index; the expansive force data comprises a first expansive force peak value and a second expansive force peak value corresponding to each charging process or each discharging process; and 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 to-be-tested cell. According to the embodiment of the invention, the technical problems that the period required for obtaining the battery cell expansion force inflection point is long and the battery production period requirement is difficult to meet in the related technology can be solved.

Description

Technical Field

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

[0002] During the charging stage of lithium-ion batteries, the expansion force of the battery cell will continue to increase due to factors such as the formation of the solid electrolyte interface (SEI) layer and the expansion of particles caused by lithium embedding in graphite. In practical applications, the inflection point of the expansion force is usually marked as the key point where the expansion behavior of the battery cell changes significantly. After the expansion force reaches the inflection point, the growth rate of the expansion force will accelerate, which may cause safety problems such as deformation or rupture of the battery shell.

[0003] In the related art, the expansion force curve is usually drawn by obtaining the maximum expansion force value during each charge and discharge cycle of the battery cell. This not only has a certain error with the actual expansion force growth curve, but the cycle required to test to the inflection point of the expansion force is too long, which is difficult to meet the production cycle requirements of the battery.

[0004] The above statements are only used to provide background 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, production method, device, electronic device, storage medium, and program product, which can solve the technical problem in the related technology that the period required to obtain the inflection point of the battery cell expansion force is long and difficult to adapt to the production cycle requirements of the battery.

[0006] In a first aspect, the present application provides a battery detection method, comprising: obtaining expansion force data corresponding to each cycle process 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 the expansion force inflection point of the battery cell to be tested.

[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 relying only on the maximum expansion force value to further obtain the inflection point of the battery cell expansion force, the present application can not only determine the growth trend of the expansion force by obtaining the expansion force peak value during the charging and discharging process within a preset number of cycles, but also can quickly determine the expansion force inflection point, which greatly shortens the battery cell detection cycle, improves the production quality of the battery, has small limitations, and high universality.

[0008] The method 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, includes: determining a target cycle round corresponding to a 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; and 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.

[0009] In an embodiment of the present application, by analyzing the expansion force peak value within a preset number of cycles, 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 is determined as the expansion force inflection point peak value corresponding to the battery cell, so that the expansion force inflection point of the battery cell can be quickly identified, the battery cell detection cycle is greatly shortened, and the accuracy of the battery cell safety performance detection is improved.

[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; The method 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, 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; 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; and determining the intersection 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.

[0011] In the embodiment of the present application, by combining the battery health as a reference parameter, the real state of the battery cell can be more accurately reflected. By combining the battery health change trend with the expansion force peak value, the expansion force inflection point corresponding to the battery cell to be tested can be more accurately located. The expansion force inflection point corresponding to the battery cell to be tested is determined by the above-mentioned first expansion force curve and the second expansion force curve, which can significantly enhance the visualization effect in the process of obtaining the expansion force inflection point.

[0012] In some embodiments, before obtaining the battery health and 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, performing a preset number of charge and discharge operations on the battery cell to be tested; 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, the first state of charge being greater than the second state of charge.

[0013] The embodiment of the present application charges the battery cell to be tested to a first state of charge and discharges the battery cell to be tested to a second state of charge according to a preset cycle strategy, and can complete multiple charge and discharge cycles in a relatively short time, quickly obtain the health and expansion force data of the battery cell, thereby shortening the detection cycle and significantly improving the efficiency of battery charging.

[0014] 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. The embodiments of the present application simulate actual working conditions by performing cycle tests under full charge and near full discharge conditions, which can more realistically reflect the performance of the battery cell in actual use. Through testing under extreme working conditions, the expansion force changes and health status of the battery cell can be observed more quickly, thereby improving the accuracy of battery cell detection.

[0015] In some embodiments, based on the preset battery cell cycling strategy, the charge and discharge operations for a preset number of cycles are performed on the battery cell to be tested, including: leaving the battery cell to be tested stationary for a first preset time period, and charging the battery cell to be tested at a constant current based on a first charging rate until the battery cell to be tested reaches a maximum charging voltage; charging the battery cell to be tested at a constant voltage with 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; leaving the battery cell to be tested stationary for a second preset time period, and discharging the battery cell to be tested based on a first discharge rate until the battery cell to be tested reaches a minimum voltage.

[0016] The embodiments of the present application simulate the actual use scenario of the battery cell. By simulating the charging and discharging process in actual use, it can more realistically reflect the performance of the battery cell in actual application. By performing cycle tests in the fully charged and nearly fully discharged states, the expansion force changes and health status of the battery cell can be more clearly observed, thereby improving the accuracy of battery cell detection. The static step reduces polarization, thereby ensuring the accuracy and reliability of the battery cell test data.

[0017] In some embodiments, the battery detection method also includes: 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 based on the correspondence between the battery health and expansion force data of each cycle; determining 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; and predicting the expansion force inflection point of the battery cell to be tested based on the first expansion force fitting function.

[0018] The embodiment of the present application determines the 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, further analyzes the relationship between the battery health and expansion force data within the first health range, and establishes a fitting function. This can more accurately capture the initial trend of the expansion force growth of the battery cell, thereby improving the accuracy of the expansion force inflection point prediction and reducing the error caused by relying solely on experimental data.

[0019] In some embodiments, the first health range is the health range of the tested battery cell before it reaches the expansion force inflection point. The embodiment of the present application analyzes the relationship between health and expansion force data and establishes a fitting function, which can accurately predict the expansion force inflection point of the battery cell without testing the expansion force inflection point, and can also reduce the error caused by relying solely on experimental data.

[0020] In some embodiments, the above-mentioned battery detection method also includes: determining a second expansion force fitting function corresponding to the battery cell to be tested based on the correspondence between the battery health and 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; wherein the second health range is the health range after the battery cell reaches the expansion force inflection point; and predicting the expansion force value of the battery cell to be tested based on the second expansion force fitting function.

[0021] The embodiment of the present application determines the second health range after the battery cell reaches the expansion force inflection point, further analyzes the relationship between the battery health and expansion force data within the first health range, and establishes a fitting function. This can more accurately capture the growth trend of the expansion force of the battery cell after the expansion force inflection point, significantly improves the accuracy of expansion force prediction, and reduces the error caused by relying solely on experimental data.

[0022] In some embodiments, the battery detection method further includes: determining the termination health corresponding to the battery cell to be tested when reaching the end-of-life state; determining the target expansion force value corresponding to the termination health based on the second expansion force fitting function; and determining whether the battery cell to be tested has an abnormality during use based on the target expansion force value. The present application combines the fitting function of health and expansion force data to more accurately predict the end-of-life state of the battery cell. By predicting the target expansion force value corresponding to the termination health, it is possible to provide an early warning when an abnormality occurs before the battery cell reaches the end-of-life state, thereby reducing potential safety issues of the battery cell.

[0023] 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.

[0024] In a third aspect, an embodiment of the present invention provides a battery detection device, comprising: an acquisition unit, used to obtain 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; a first determination unit, 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.

[0025] In a fourth aspect, an embodiment of the present application further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the battery detection method as described in the first aspect is implemented.

[0026] In a fifth aspect, an embodiment of the present application further provides a computer-readable storage medium, wherein the computer-readable storage medium stores 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.

[0027] 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.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings: Figure 1 A flowchart of a battery detection method provided according to an embodiment of the present application; Figure 2 A flowchart of another battery detection method provided in an embodiment of the present application; Figure 3 A flowchart of another battery detection method provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of a battery expansion force detection device provided in an embodiment of the present application; Figure 5 A schematic diagram of an expansion force-SOC curve of a battery provided in an embodiment of the present application; Figure 6 is a schematic diagram of an expansion force curve provided in an embodiment of the present application; Figure 7 is another schematic diagram of an expansion force curve provided in an embodiment of the present application; Figure 8 is a structural schematic diagram of a battery detection device provided in an embodiment of the present application; Fig. 9 is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] The following embodiments of the technical solution of the present application will be described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0032] In the description of the embodiments of the present invention, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0033] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0034] In the description of the embodiments of the present invention, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0035] In the description of the embodiments of the present invention, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0036] At present, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. In the fields of electric transportation supply, military equipment, aerospace and so on, batteries are usually used to provide power.

[0037] Among various types of power batteries, lithium batteries are widely used in new energy vehicles, consumer electronics, energy storage systems and other fields due to their advantages such as high power density, high energy density, long cycle life, high output voltage, and green environmental protection. How to improve the charging speed of lithium batteries while ensuring charging performance has become a hot topic of current research.

[0038] As the degree of cycle aging (or storage aging) of lithium batteries increases, the solid electrolyte interface (SEI) will undergo a destruction / repair process, the SEI layer will thicken, and the positive and negative pole pieces will rebound, all of which will increase the expansion force of the lithium battery cell; when this expansion force increases to a certain range, it will affect the structure of the battery module, such as battery performance degradation, battery shell rupture, electrolyte leakage, internal battery short circuit and other safety hazards. Due to possible abnormalities in incoming materials, abnormal environmental water content, abnormal production process parameters, etc. during the production process, the expansion force of the battery cell of the battery product will exceed the safe range.

[0039] During the charging stage of lithium-ion batteries, the expansion force of the battery cell will continue to increase due to factors such as the formation of the solid electrolyte interface (SEI) layer and the expansion of particles caused by lithium embedding in graphite. In practical applications, the inflection point of the expansion force is usually marked as the key point where the expansion behavior of the battery cell changes significantly. After the expansion force reaches the inflection point, the growth rate of the expansion force will accelerate, which may cause safety problems such as deformation or rupture of the battery shell.

[0040] In the related art, the expansion force curve is usually drawn by obtaining the maximum expansion force value during each charge and discharge cycle of the battery cell. This not only has a certain error with the actual expansion force growth curve, but the cycle required to test to the inflection point of the expansion force is too long, which is difficult to meet the production cycle requirements of the battery.

[0041] Based on the above problems existing in the related art, the present application proposes a battery detection method, device, electronic device and storage medium. The battery detection method includes: obtaining the 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 the first expansion force peak value and the 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.

[0042] In the technical solution of the embodiment of the present invention, the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles is obtained; 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 method in the related art of determining the growth curve of the expansion force by relying only on the maximum expansion force value to further obtain the inflection point of the battery cell expansion force, the present application can not only determine the growth trend of the battery cell expansion force by obtaining the expansion force peak value during the charging and discharging process within a preset number of cycles, but also can quickly determine the expansion force inflection point, which greatly shortens the battery cell detection cycle, improves the production quality of the battery, has small limitations and high universality.

[0043] The specific process of the battery detection method of the present application is described in detail below through specific embodiments. Figure 1 The flowchart of the battery detection method shown in FIG. 1 includes the following steps: S102, 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; S104, determining an 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.

[0044] Specifically, in an embodiment of the present invention, the above-mentioned battery cell type may be, for example, a ternary lithium battery cell or a lithium iron phosphate battery cell. The above-mentioned preset number of cycles may be adjusted according to actual R&D or production needs. For example, for mass production sampling batteries, more than 100 cycles are required, and for batteries involved in the corresponding R&D process, more than 500 cycles are required. In order to obtain the expansion force of each battery cell to be tested during the battery production process, it is necessary to use a clamp to monitor the expansion force of the battery cell during the production process. Figure 4 As shown, the embodiment of the present application can use, for example, three steel clamps 402 and two fixings 404 to fix the battery cell 408 to be tested and the pressure sensor 406, and the battery cell 408 to be tested and the pressure sensor 406 are respectively located between the two steel clamps 402, and the expansion force value during the battery cell test is monitored by obtaining the output value of the pressure sensor. Based on the above method, the corresponding expansion force value of each battery cell under different states of charge (SOC) during the cycle process can be obtained.

[0045] During the charging or discharging stage of lithium-ion batteries, the expansion force of the battery cell will change due to factors such as the formation of the SEI layer and the expansion of particles caused by the insertion of lithium into graphite. Figure 5 As shown, at the charging node of the battery cell to be tested, the battery cell to be tested has a maximum expansion force point near 30% SOC, i.e., a first expansion force value F1, and has a maximum expansion force point near 95% SOC, i.e., a second expansion force value F2.

[0046] In one example, for example, the first expansion force peak value and the second expansion force peak value corresponding to each charging process and the first expansion force peak value and the second expansion force peak value corresponding to each discharging process of the battery cell to be tested within 200 cycles are obtained; that is, the first expansion force peak value and the second expansion force peak value corresponding to 200 charging processes and the first expansion force peak value and the second expansion force peak value corresponding to 200 discharging processes can be obtained. In one cycle, the first expansion force peak value corresponding to the discharging process is less than or equal to the first expansion force peak value corresponding to the charging process, and the second expansion force peak value corresponding to the discharging process is less than or equal to the second expansion force peak value corresponding to the charging process.

[0047] According to the first expansion force peak value and the second expansion force peak value during the above-mentioned charging process or discharging process, the present application can accurately determine the expansion force inflection point of the battery cell to be tested.

[0048] In the technical solution of the embodiment of the present invention, the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles is obtained; 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 method in the related art of determining the growth curve of the expansion force by relying only on the maximum expansion force value to further obtain the inflection point of the battery cell expansion force, the present application can not only determine the growth trend of the battery cell expansion force by obtaining the expansion force peak value during the charging and discharging process within a preset number of cycles, but also can quickly determine the expansion force inflection point, which greatly shortens the battery cell detection cycle, improves the production quality of the battery, has small limitations and high universality.

[0049] In one or more embodiments of the present application, Figure 2 As shown, the above battery detection method includes the following steps: S102, 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; S204, determining a target cycle round corresponding to a 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; S206, determining an 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.

[0050] Specifically, in an embodiment of the present invention, by analyzing the first expansion force peak value and the second expansion force peak value corresponding to each charging round and each discharging round within a preset number of cycles, it is determined whether the first expansion force peak value and the second expansion force peak value in each charging round or each discharging round are the same; it should be noted that the target cycle round in the embodiment of the present application may be a round in which the first expansion force peak value and the second expansion force peak value are equal in a charging round or a discharging round.

[0051] In one example, for example, the cycle corresponding to the charging round corresponding to the case where the first expansion force peak value and the second expansion force peak value are the same is determined as the target cycle. The charging round is the critical point where the expansion force of the battery cell to be tested changes significantly. Afterwards, the expansion force inflection point of the battery cell to be tested is determined based on the first expansion force peak value or the second expansion force peak value of the charging round (target cycle).

[0052] The above step S102 has been explained in the previous text and will not be repeated here.

[0053] In an embodiment of the present application, by analyzing the expansion force peak value within a preset number of cycles, 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 is determined as the expansion force inflection point peak value corresponding to the battery cell, so that the expansion force inflection point of the battery cell can be quickly identified, the battery cell detection cycle is greatly shortened, and the accuracy of the battery cell safety performance detection is improved.

[0054] In one or more embodiments of the present application, Figure 3 As shown, the above battery detection method includes the following steps: S102, 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; S304, obtaining the battery health corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; S306, 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; S308, 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; S310: Determine the intersection 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.

[0055] Specifically, in the embodiment of the present application, within the preset number of cycles, the battery state of health (SOH) corresponding to each cycle is recorded. In one example, the battery state of health corresponding to each cycle may be the SOH corresponding to each charging process, or the SOH corresponding to each discharging process. The battery state of health here can be evaluated by the capacity retention rate of the battery cell, the change in internal resistance, or other performance indicators.

[0056] like Figure 6 As shown, according to the corresponding relationship between the battery health and the first expansion force peak value during each cycle, a first expansion force curve is created, and the first expansion force curve reflects the change trend of the expansion force peak value of the battery cell during the charging process with the health; according to the corresponding relationship between the battery health and the second expansion force peak value during each cycle, a second expansion force curve is created, and the second expansion force curve reflects the change trend of the expansion force peak value of the battery cell during the charging process with the health. The intersection point (point P) 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. The expansion force inflection point is the point where the expansion force growth rate of the battery cell changes significantly, that is, the change of the internal structure of the battery cell or potential health problems.

[0057] Since there is a certain buffering effect between the initial bare battery cell (Jelly-Roll, referred to as JR) and the outer aluminum shell, the bare battery cell needs to consume about 3% of the active lithium to reach the state of complete top shell. Therefore, the increase of the first expansion force peak value and the second expansion force peak value in the 100%~97%SOH range is not obvious. After JR reaches the state of complete top shell, the first expansion force peak value and the second expansion force peak value both 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.

[0058] The above step S102 has been explained in the previous text and will not be repeated here.

[0059] In the embodiment of the present application, by combining the battery health as a reference parameter, the real state of the battery cell can be more accurately reflected. By combining the battery health change trend with the expansion force peak value, the expansion force inflection point corresponding to the battery cell to be tested can be more accurately located. The expansion force inflection point corresponding to the battery cell to be tested is determined by the above-mentioned first expansion force curve and the second expansion force curve, which can significantly enhance the visualization effect in the process of obtaining the expansion force inflection point.

[0060] In one or more embodiments, before obtaining the battery health and 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.

[0061] Specifically, in an embodiment of the present application, before obtaining the health and expansion force data of the battery cell to be tested, it is necessary to perform charging and discharging operations according to a preset battery cell cycling strategy. For example, in the charging process of each cycle, the battery cell to be tested is charged to a first state of charge, and the value range of the first state of charge can be, for example, [95%, 100%] SOC, and the value range of the 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 undergoes a complete charging and discharging condition during the test process, thereby providing a comprehensive and accurate reference for the subsequent prediction of the inflection point of the battery cell expansion force.

[0062] The embodiment of the present application charges the battery cell to be tested to a first state of charge and discharges the battery cell to be tested to a second state of charge according to a preset cycle strategy, and can complete multiple charge and discharge cycles in a relatively short time, quickly obtain the health and expansion force data of the battery cell, thereby shortening the detection cycle and significantly improving the efficiency of battery charging.

[0063] In one or more embodiments, the first state of charge is a state of charge corresponding to a full charge, and / or the second state of charge is a state of charge corresponding to a full discharge.

[0064] The embodiment of the present application simulates actual working conditions by performing cycle tests under full charge and nearly full discharge conditions, which can more realistically reflect the performance of the battery cell in actual use. Through testing under extreme working conditions, the expansion force changes and health status of the battery cell can be obtained more quickly, thereby improving the accuracy of battery cell detection.

[0065] In one or more embodiments, the performing of 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.

[0066] Specifically, the value range of the first preset time length may be, for example, [5-15] minutes, the value range of the second preset time length may be [5-15] minutes, and the first charging rate may be 1C. The second charging rate may be 0.05C. For example, for a 1000mAh battery, 0.05C corresponds to a current of 50mA, and the maximum charging voltage Vmax of the lithium-ion battery is 4.2V, and the minimum voltage Vmin is 2.5V.

[0067] In one example, the charge and discharge test process used in this application includes: 1) Rest for 10 minutes; allow the battery to reach chemical equilibrium before testing, reduce polarization effects, and ensure the accuracy of subsequent tests.

[0068] 2) 1C CC Vmax (charge at a constant current of 1C until the battery voltage reaches the maximum voltage Vmax); 3) Vmax CV0.05C (when the battery voltage reaches Vmax, switch to constant voltage charging mode until the charging current drops to 0.05C); 4) Rest for 10 minutes; allow the battery to reach chemical equilibrium after charging, reduce polarization effects, and ensure the accuracy of subsequent discharge tests.

[0069] 5) 1C DC Vmin (discharge at a constant current of 1C until the battery voltage drops to the minimum voltage Vmin); 6) Loop through steps 1) to 5) for a total of x times; for mass production sampled cells, x is greater than or equal to 100; for R&D cells, x is greater than or equal to 500. The embodiments of the present application simulate the actual use scenario of the battery cell. By simulating the charging and discharging process in actual use, it can more realistically reflect the performance of the battery cell in actual application. By performing cycle tests in the fully charged and nearly fully discharged states, the expansion force changes and health status of the battery cell can be more clearly observed, thereby improving the accuracy of battery cell detection. The static step reduces polarization, thereby ensuring the accuracy and reliability of the battery cell test data.

[0070] In one or more embodiments, the battery detection method further includes: 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.

[0071] Since the first expansion force peak value and the second expansion force peak value both increase linearly after JR reaches the fully top shell state, in the embodiment of the present application, by analyzing the rate of change of the first expansion force peak value and the rate of change of the second expansion force peak value, an interval in which the rate of change remains stable is found, and the health range corresponding to the interval is determined as the first health range. Select a suitable mathematical model (such as a linear or nonlinear regression model).

[0072] A first expansion force fitting function is obtained by fitting the data within the first health range. The function can describe the trend of expansion force changing with health. The first expansion force fitting function includes a fitting function corresponding to the first expansion force peak value and a fitting function corresponding to the second expansion force peak value.

[0073] The embodiment of the present application determines the 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, further analyzes the relationship between the battery health and expansion force data within the first health range, and establishes a fitting function. This can more accurately capture the initial trend of the expansion force growth of the battery cell, thereby improving the accuracy of the expansion force inflection point prediction and reducing the error caused by relying solely on experimental data.

[0074] In one or more embodiments, the first health range is the health range of the battery cell to be tested before it reaches the expansion force inflection point.

[0075] In the embodiment of the present application, it is not necessary to test the inflection point of the expansion force. It is only necessary to test the 1% active lithium loss after JR reaches the top shell, that is, according to the linear part of 95%~96% active lithium loss (the battery health is in the range of 95%~96%), the linear part is fitted. In one example, Figure 7As shown, based on the first expansion force curve, the fitting function corresponding to the first expansion force peak is: y=-5088.1x+5075.3; based on the second expansion force curve, the fitting function corresponding to the second expansion force peak is: y=-4091.8x+4159.3; where y represents the actual expansion force value and x represents the battery health. Solving the above two fitting functions, the predicted expansion force inflection point value is: 91.931%SOH.

[0076] The application embodiment analyzes the relationship between health and expansion force data and establishes a fitting function. It can accurately predict the expansion force inflection point of the battery cell without testing the expansion force inflection point, and can also reduce the error caused by relying solely on experimental data.

[0077] In one or more embodiments, the battery detection method further includes: 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 of the battery cell after it 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.

[0078] Specifically, in an embodiment of the present application, the health and expansion force data of the battery cell to be tested within a second health range are obtained, and a corresponding mathematical model is determined based on the health and expansion force data characteristics within this range. The parameters of the fitting function are determined through regression analysis or model optimization methods so that the model can accurately describe the change of expansion force with health.

[0079] In one example, a linear model is used for prediction, and the prediction function is: F = k*(1-SOH) + b, where F is the expansion force value, SOH is the health state of the battery, and k and b are related parameters of the model output. The embodiment of the present application determines the second health range after the battery cell reaches the expansion force inflection point, further analyzes the relationship between the battery health and expansion force data within the first health range, and establishes a fitting function. This can more accurately capture the growth trend of the expansion force of the battery cell after the expansion force inflection point, significantly improves the accuracy of expansion force prediction, and reduces the error caused by relying solely on experimental data.

[0080] In one or more embodiments, the battery detection method further includes: 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.

[0081] Specifically, in the embodiment of the present application, assuming that the termination health degree corresponding to the tested cell is 60%, the termination health degree 60% is substituted into the second expansion force fitting function to calculate the corresponding target expansion force value. If the expansion force value corresponding to the tested cell is greater than or equal to the target expansion force value during use, it indicates that an abnormality has occurred in the tested cell; otherwise, the expansion force value corresponding to the tested cell is greater than or equal to the target expansion force value, it indicates that no abnormality has occurred in the tested cell.

[0082] The present application combines the fitting function of health and expansion force data to more accurately predict the end-of-life state of the battery cell. By predicting the target expansion force value corresponding to the terminal health, it is possible to provide early warning when an abnormality occurs before the battery cell reaches the end-of-life state, thereby reducing potential safety issues of the battery cell.

[0083] In one or more embodiments of the present application, the present application also provides a battery production method, which includes the steps of the battery detection method in the above embodiment. Specifically, the present application can integrate or apply the above battery detection method in the battery production process, such as performing random inspections on mass-produced battery cells. In one example, the above battery detection method can also be applied to the battery research and development process. 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. Figure 8 As shown, the device comprises: The first acquisition unit 802 is 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 determining unit 804 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.

[0084] In the technical solution of the embodiment of the present invention, the expansion force data corresponding to each cycle of the battery cell to be tested within a preset number of cycles is obtained; 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 method in the related art of determining the growth curve of the expansion force by relying only on the maximum expansion force value to further obtain the inflection point of the battery cell expansion force, the present application can not only determine the growth trend of the expansion force by obtaining the expansion force peak value during the charging and discharging process within a preset number of cycles, but also can quickly determine the expansion force inflection point, which greatly shortens the battery cell detection cycle, improves the production quality of the battery, has small limitations, and high universality.

[0085] In one or more implementations of the present application, the first determining unit 804 includes: A first determination module is used to determine a target cycle round corresponding to a case where the first expansion force peak value and the second expansion force peak value are the same, wherein the target cycle round includes a target charging round or a target discharging round; The second determination module is used 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.

[0086] In one or more embodiments of the present application, the battery detection device further includes: a second acquisition unit, configured to acquire the battery health corresponding to each cycle process of the battery cell to be tested within a preset number of cycles; The first determining unit 804 includes: A first creation module, configured to create a first expansion force curve corresponding to the battery cell to be tested according to a corresponding relationship between the battery health and the first expansion force peak value during each cycle; A second creation module, configured to create a second expansion force curve corresponding to the battery cell to be tested according to a corresponding relationship between the battery health and the second expansion force peak value during each cycle; The third determination module is used to determine the intersection 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.

[0087] In one or more embodiments of the present application, the battery detection device further includes: A charge and discharge unit is used to perform a preset number of charge and discharge operations on the battery cell to be tested 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.

[0088] In one or more embodiments of the present application, 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.

[0089] In one or more embodiments of the present application, the charge-discharge unit includes: A static charging module, used for placing the battery cell to be tested at rest for a first preset time, and 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 a maximum charging voltage; A charging module, used for 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, so that the battery cell to be tested reaches a fully charged state; The static discharge module is used to keep the battery cell to be tested static for a second preset time period and discharge the battery cell to be tested based on a first discharge rate until the battery cell to be tested reaches a minimum voltage.

[0090] In one or more embodiments of the present application, the battery detection device further includes: a second determining unit, configured to determine, based on a correspondence between the battery health and the expansion force data of each cycle, a first health range corresponding to the battery cell to be tested when a rate of change of the first expansion force peak value and a rate of change of the second expansion force peak value remain unchanged; A third determining 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 a first health range; The first prediction unit is used to predict the expansion force inflection point of the battery cell to be tested based on the first expansion force fitting function.

[0091] In one or more embodiments of the present application, the first health range is a health range before the battery cell to be tested reaches the expansion force inflection point.

[0092] In one or more embodiments of the present application, the battery detection device further includes: a fourth determining unit, configured to determine a second expansion force fitting function corresponding to the battery cell to be tested based on the corresponding relationship and the battery health and expansion force data of the battery cell to be tested within a second health range; wherein the second health range is a health range after the battery cell to be tested reaches the expansion force inflection point; The second prediction unit is used to predict the expansion force value of the battery cell to be tested based on the second expansion force fitting function.

[0093] In one or more embodiments of the present application, the battery detection device further includes: A fifth determining unit, configured to determine a termination health corresponding to the battery cell to be tested when reaching an end-of-life state; A sixth determining unit, configured to determine a target expansion force value corresponding to the termination health level based on a second expansion force fitting function; The seventh determination unit is used to determine whether the battery cell to be tested has an abnormality during use based on the target expansion force value.

[0094] Fig. 9 9 is a logical structure block diagram of an electronic device according to an exemplary embodiment. For example, the electronic device 900 may be an electronic device such as a BMS, a vehicle controller, a motor controller, or a domain controller that is disposed inside an electric device.

[0095] In an exemplary embodiment, a non-transitory computer-readable storage medium including instructions is also provided, such as a memory including instructions, and the above instructions can be executed by a battery processor to complete the above battery detection method, the method comprising: obtaining the 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 the first expansion force peak value and the 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. 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, an optical data storage device, etc.

[0096] In an exemplary embodiment, an application / computer program product is also provided, including one or more instructions, which can be executed by a processor of a battery to complete the above-mentioned battery detection method, the method comprising: obtaining 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, determining the expansion force inflection point of the battery cell to be tested. Optionally, the above-mentioned instructions can also be executed by a processor of a battery to complete other steps involved in the above-mentioned exemplary embodiment. Fig. 9 FIG. 9 is an example diagram of an electronic device 900. A person skilled in the art can understand that Fig. 9It is only an example of the electronic device 900 and does not constitute a limitation of the electronic device 900. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the electronic device 900 may also include input and output devices, network access devices, buses, etc.

[0097] The processor 902 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A 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 uses various interfaces and lines to connect various parts of the entire electronic device 900.

[0098] The memory 901 can be used to store computer-readable instructions. The processor 902 implements various functions of the electronic device 900 by running or executing the computer-readable instructions or modules stored in the memory 901 and calling the data stored in the memory 901. The memory 901 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the electronic device 900, etc. In addition, the memory 901 can include a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM) or other non-volatile / volatile storage devices.

[0099] If the module integrated in the electronic device 900 is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also instruct the relevant hardware to complete the computer-readable instructions through computer-readable instructions. The computer-readable instructions can be stored in a computer-readable storage medium, and when the computer-readable instructions are executed by the processor, the steps of the above-mentioned various method embodiments can be implemented.

[0100] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention disclosed herein. The present application is intended to cover any modification, use or adaptation of the present application, which follows the general principles of the present application and includes common knowledge or customary techniques in the art that are not disclosed in the present application. The specification and examples are intended to be exemplary only, and the true scope and spirit of the present application are indicated by the following claims.

[0101] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

[0102] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this 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 must comply with the relevant laws, regulations and standards of relevant countries and regions, and provide corresponding operation entrances 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, the expansion force inflection point of the battery cell to be tested is determined.

2. The method according to claim 1, characterized in that 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: Determine a target cycle round corresponding to a case where the first expansion force peak value and the second expansion force peak value are the same, wherein the target cycle round includes a target charging round or a target discharging round; The expansion force inflection point of the battery cell to be tested is determined according to the first expansion force peak value or the second expansion force peak value of the target cycle.

3. 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.

4. The method according to any one of claims 1 to 3, 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.

5. The method according to claim 4, 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.

6. The method according to claim 4, 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.

7. The method according to any one of claims 1 to 3, 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.

8. The method according to claim 7, 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.

9. The method according to claim 7, 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.

10. The method according to claim 9, 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.

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

12. 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.

13. 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 11 through the computer program.

14. 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 11 when executed.

15. 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 11.

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