Method and device for testing battery shell

Abstract

The invention relates to the technical field of battery testing, and discloses a battery shell testing method and device. The method comprises the steps of determining total change data based on first parameter change data and second parameter change data of a target battery; the total change data is used for indicating the change condition of the total pressure generated by superposition of the expansion pressure and the gas generation pressure of the target battery along with the charge-discharge cycle times; applying k + 1 times of pressure to the shell of the target battery based on the total pressure corresponding to the ith charge-discharge cycle to the (i + k) th charge-discharge cycle indicated by the total change data; when the shell subjected to pressure application meets a preset requirement and i does not reach a preset value, i is made to be equal to i + k + 1 so as to circularly apply pressure to the shell until i reaches the preset value or the shell subjected to pressure application does not meet the preset requirement, and a test result is obtained; the bearing capacity of the target battery to the generated air pressure and the circulating pressure can be tested, and the accuracy of the strength test result of the battery cell shell is improved.

Description

Technical Field

[0001] This disclosure relates to the field of battery testing technology, and in particular to a method and apparatus for testing battery casings. Background Technology

[0002] Rechargeable batteries, as reusable energy storage units, are widely used in portable electronic devices, power tools, energy storage systems, electric vehicles, electric aircraft, and other applications. A rechargeable battery includes a battery core, which comprises a casing, a top cover, and the core assembly enclosed by the casing and top cover. The casing can be a rigid structure such as a cylinder or a square.

[0003] Generally, the casing and top cover are permanently sealed using laser welding to isolate the external environment and house the internal components. Since the strength of the casing (including the strength of the welded portion to the top cover) affects the rechargeable battery's seal and thus its lifespan, assessing the strength of the battery casing is crucial.

[0004] In a typical battery casing test method, the maximum pressure resistance limit of the casing is determined by continuously increasing the pressure applied to the casing. If the maximum pressure resistance limit reaches the preset strength, the casing is determined to be qualified in terms of strength; if the maximum pressure resistance limit does not reach the preset strength, the casing is determined to be unqualified in terms of strength.

[0005] However, traditional testing methods only consider the ability of the casing to withstand pressure once, ignoring the fatigue load that the battery endures throughout its entire life cycle, i.e., the phenomenon of damage caused by repeated cyclic stress below the casing strength limit. This leads to inaccurate casing strength test results. Summary of the Invention

[0006] In view of this, this disclosure proposes a testing method and apparatus for battery casings, which can solve the problem that traditional casing testing methods cannot determine the fatigue load caused by cyclic pressure, thus resulting in inaccurate test results for battery casings.

[0007] According to one aspect of this disclosure, a method for testing a battery casing is provided, the method comprising:

[0008] Acquire first parameter change data and second parameter change data of the target battery to be tested; wherein, the first parameter change data is used to indicate the change of the expansion pressure of the target battery with the number of charge-discharge cycles; the second parameter change data is used to indicate the change of the gas generation pressure of the target battery with the number of charge-discharge cycles;

[0009] Based on the change data of the first parameter and the change data of the second parameter, the total change data is determined; the total change data is used to indicate the change of the total pressure generated by the superposition of the expansion pressure and the gas production pressure of the target battery with the number of charge and discharge cycles.

[0010] Based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, apply pressure k+1 times to the casing of the target battery.

[0011] If the casing meets the preset requirements after pressure is applied, and i does not reach the preset value, let i = i + k + 1, trigger the execution of the step of applying pressure to the casing of the target battery k + 1 times based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, and the subsequent steps, until i reaches the preset value or the casing does not meet the preset requirements after pressure is applied, and stop to obtain the test result; where i is a positive integer starting from 1, and k is a positive integer.

[0012] In one possible implementation, the first parameter change data of the target battery to be tested is obtained, including:

[0013] A finite element model of the target battery is established based on its structure;

[0014] Expansion force simulation was performed based on the finite element model to obtain the first parameter variation data under each operating environment.

[0015] In one possible implementation, the second parameter variation data of the target battery to be tested is obtained, including:

[0016] Based on the chemical reactions that occur in the target battery during charging and discharging, the change data of the second parameter corresponding to the chemical reactions under each operating environment are determined.

[0017] In one possible implementation, the first parameter change data and the second parameter change data include first parameter change data and second parameter change data corresponding to each operating environment under multiple operating environments;

[0018] Accordingly, determining the total change data based on the first parameter change data and the second parameter change data includes:

[0019] The maximum expansion pressure corresponding to each charge-discharge cycle is determined from the first parameter change data corresponding to various operating environments, and the maximum gas production pressure corresponding to each charge-discharge cycle is determined from the second parameter change data corresponding to various operating environments.

[0020] The maximum expansion pressure and the maximum gas production pressure corresponding to each charge-discharge cycle are added together to obtain the total pressure corresponding to the number of charge-discharge cycles, thus obtaining the total change data.

[0021] In one possible implementation, applying pressure k times to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data includes:

[0022] Determine the maximum total pressure value corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply k+1 pressures to the casing of the target battery to generate the maximum total pressure value;

[0023] or,

[0024] Determine the average total pressure corresponding to the total pressure from the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply k+1 pressures to the casing of the target battery that can generate the average total pressure.

[0025] In one possible implementation, before applying pressure k times to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, the method further includes:

[0026] Determine the preset numerical range to which the value of i belongs;

[0027] Obtain the value of k corresponding to the preset numerical range;

[0028] The preset numerical range is at least two numerical ranges obtained by dividing the range of the number of charge-discharge cycles into intervals, and different preset numerical ranges correspond to different k values.

[0029] In one possible implementation, the preset numerical range includes a first numerical range and a second numerical range. The rate of change of total pressure corresponding to each charge-discharge cycle in the first numerical range is greater than the rate of change of total pressure corresponding to each charge-discharge cycle in the second numerical range. Accordingly, k corresponding to the first numerical range is less than k corresponding to the second numerical range.

[0030] In one possible implementation, the test stops when i reaches a preset value or when the shell after applying pressure fails to meet the preset requirements, and the test results are obtained, including:

[0031] If the casing reaches the preset requirements after pressure is applied and i reaches the preset value, the test result is determined to be that the casing of the target battery is qualified.

[0032] If the casing does not meet the preset requirements after pressure is applied, the test result is determined to be that the casing of the target battery is unqualified.

[0033] According to another aspect of this disclosure, a testing apparatus for a battery casing is provided, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above-described method.

[0034] According to another aspect of this disclosure, a non-volatile computer-readable storage medium is provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the above-described method.

[0035] According to another aspect of this disclosure, a computer program product is provided, including a computer program or a non-volatile computer-readable storage medium carrying the computer program, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0036] The test involves acquiring first and second parameter change data for the target battery. The first parameter change data indicates the change in the target battery's expansion pressure with the number of charge-discharge cycles. The second parameter change data indicates the change in the target battery's gas generation pressure with the number of charge-discharge cycles. Based on the first and second parameter change data, total change data is determined. This total change data indicates the change in the total pressure resulting from the superposition of the target battery's expansion pressure and gas generation pressure with the number of charge-discharge cycles. Based on the total pressure indicated by the total change data from the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle, pressure is applied to the target battery's casing k+1 times. The casing after applying pressure meets a preset condition. If the requirement is met and i does not reach the preset value, let i = i + k + 1, triggering the execution of the step of applying pressure to the target battery casing k + 1 times based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, and subsequent steps, until i reaches the preset value or the casing after applying pressure does not meet the preset requirements, and then stop, obtaining the test results; this can solve the problem that traditional casing testing methods cannot determine the fatigue load caused by cyclic pressure, thus leading to inaccurate battery casing test results; since it can test the target battery's ability to withstand gas generation pressure and cyclic pressure, and obtain the fatigue test results of the target battery, it can improve the accuracy of the strength test results of the battery cell casing.

[0037] Other features and aspects of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0038] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this disclosure together with the specification and serve to explain the principles of this disclosure.

[0039] Figure 1 A flowchart illustrating a test method for a battery casing according to an embodiment of the present disclosure is shown;

[0040] Figure 2 A schematic diagram showing first parameter change data, second parameter change data, and total change data according to an embodiment of the present disclosure is provided.

[0041] Figure 3 A block diagram showing a test apparatus for a battery casing according to an embodiment of the present disclosure;

[0042] Figure 4 A block diagram of a test apparatus for a battery casing according to another embodiment of the present disclosure is shown. Detailed Implementation

[0043] Various exemplary embodiments, features, and aspects of this disclosure will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0044] As used herein, the terms “comprising,” “including,” “having,” or variations thereof are open-ended and include one or more of the stated features, integrals, elements, steps, components, or functions, but do not exclude the presence or addition of one or more other features, integrals, elements, steps, components, functions, or groups thereof.

[0045] When an element is referred to as “connected,” “coupled,” “responding,” or a variation thereof relative to another element, it may be directly connected, coupled, or responding to another element, or there may be an intermediate element present.

[0046] Although the terms first, second, third, etc., may be used herein to describe various elements / operations, these elements / operations should not be limited by these terms. These terms are only used to distinguish one element / operation from another. Therefore, without departing from the teachings of the inventive concept, a first element / operation in some embodiments may be referred to as a second element / operation in other embodiments.

[0047] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0048] Furthermore, to better illustrate this disclosure, numerous specific details are set forth in the following detailed description. Those skilled in the art will understand that this disclosure can be practiced without certain specific details. In some instances, methods, means, components, and circuits well known to those skilled in the art have not been described in detail in order to highlight the main points of this disclosure.

[0049] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, data stored, data displayed, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant regions.

[0050] During each charge-discharge cycle, a rechargeable battery undergoes a chemical reaction within its core, producing gases (i.e., gas generation). This gas generation exerts pressure on the battery casing (specifically, the core). For example, in lithium-ion batteries, overcharging can cause the solvent molecules in the electrolyte to oxidize, producing gases such as carbon dioxide (CO2) and carbon monoxide (CO). The accumulation of these gases inside the battery increases the internal gas generation pressure.

[0051] One charge-discharge cycle refers to the process by which a battery completes one full charge and discharge cycle.

[0052] In addition, as the number of charge-discharge cycles increases, some irreversible changes may occur inside the battery core. For example, the decomposition reaction of the electrolyte may intensify, producing more and more gas. If these gases cannot be expelled from the battery in time, the gas pressure inside the battery will gradually increase with the number of charge-discharge cycles.

[0053] On the other hand, during each charge-discharge cycle, the core inside the battery alternately expands and contracts. Specifically, during charging, the core expands, increasing its thickness and exerting an outward pushing force on the battery casing, causing pressure on the casing. During discharging, the thickness of the core decreases, and the pressure on the casing decreases accordingly. At this time, the battery casing experiences expansion pressure due to the expansion of the core.

[0054] Among them, the core refers to the structure formed by winding or stacking positive electrode plates, negative electrode plates, and separators, which is the direct site of electrochemical reactions.

[0055] In addition, as the number of charge-discharge cycles increases, the aging of the core material intensifies, and the expansion of the core may become more pronounced, causing the internal expansion pressure of the battery to gradually increase with the number of charge-discharge cycles.

[0056] The two types of cyclic pressure (i.e., gas generation pressure and cyclic pressure) will not cause damage to the battery casing in one go. However, as the number of battery charge-discharge cycles increases, the long-term combined action of these two cyclic pressures on the welded joints of the casing and top cover may cause fatigue at the weld joints, leading to a safety risk of premature cracking.

[0057] Current battery casing testing methods do not consider fatigue loads caused by cyclic pressure, leading to inaccurate test results. Therefore, this application proposes a battery casing testing method that can test the target battery's ability to withstand gas generation pressure and cyclic pressure, obtaining fatigue test results and thus improving the accuracy of strength test results for the battery casing (specifically, the casing of the battery cell).

[0058] The following is a detailed description of the testing method for the battery casing provided in this application. This embodiment uses the method in an electronic device as an example for illustration. The electronic device can be a user terminal or server with processing capabilities. The user terminal can be a computer, tablet computer, mobile phone, etc. This embodiment does not limit the implementation method of the electronic device.

[0059] Figure 1 A flowchart illustrating a testing method for a battery casing according to an embodiment of the present disclosure is shown. Figure 1 As shown, the method includes:

[0060] Step 101: Obtain the first parameter change data and the second parameter change data of the target battery to be tested.

[0061] The first parameter variation data is used to indicate how the expansion pressure of the target battery changes with the number of charge-discharge cycles. In one example, obtaining the first parameter variation data of the target battery to be tested includes: establishing a finite element model of the target battery based on its structure; performing expansion force simulation based on the finite element model to obtain the first parameter variation data under each operating environment.

[0062] The finite element model refers to the virtual battery structure that discretizes the structure of the real target battery (specifically, the structure of the cell in the target battery) into a finite number of units and simulates the mechanical, thermal, electrochemical and other multi-physics field responses of each unit through numerical methods. The finite element model includes the geometric structure of the target battery and also includes a simulation system that simulates the various behaviors of the target battery during operation.

[0063] After constructing the finite element model, the target battery is subjected to multiple charge-discharge cycles based on the finite element model. The expansion pressure on the casing due to the core expansion during each charge-discharge cycle is obtained. The expansion pressure corresponding to multiple charge-discharge cycles constitutes the first parameter variation data. For example, the first parameter variation data is a curve generated based on the expansion pressure corresponding to multiple charge-discharge cycles, and this curve is referenced... Figure 2 The expansion pressure curve 201 is shown.

[0064] Optionally, since the expansion pressure of the target battery may vary with the number of charge-discharge cycles under different operating environments, when simulating multiple charge-discharge cycles of the target battery based on the finite element model, various operating environments of the target battery can also be simulated to obtain the change data of the first parameter corresponding to each operating environment.

[0065] The operating environment refers to the environment in which the target battery is located. Different operating environments may have different environmental parameters such as temperature and / or atmospheric pressure. This embodiment does not limit the type of environmental parameters.

[0066] The second parameter variation data is used to indicate how the gas generation pressure of the target battery changes with the number of charge-discharge cycles. In one example, obtaining the second parameter variation data of the target battery to be tested includes: determining the second parameter variation data corresponding to the chemical reactions that occur in the target battery during charge and discharge under different operating conditions.

[0067] Since the chemical reaction occurring during the charging and discharging of the target battery produces gas, and the total number of moles of this gas can be calculated from the chemical reaction, the total number of moles of gas produced in each charge-discharge cycle can be converted into gas production pressure according to the ideal gas law. This yields the gas production pressure corresponding to each charge-discharge cycle. The gas production pressure corresponding to multiple charge-discharge cycles constitutes the second parameter variation data. For example, the second parameter variation data is a curve generated based on the gas production pressure corresponding to multiple charge-discharge cycles, and this curve is referenced... Figure 2 The gas production pressure curve 202 is shown.

[0068] Optionally, since the gas generation pressure of the target battery may vary with the number of charge-discharge cycles under different operating environments, when determining the change data of the second parameter corresponding to the chemical reaction, the gas generation pressure corresponding to each operating environment can also be calculated by combining the environmental parameters (such as temperature, atmospheric pressure, etc.) of different operating environments, thereby obtaining the change data of the second parameter corresponding to each operating environment.

[0069] Step 102: Based on the change data of the first parameter and the change data of the second parameter, determine the total change data; the total change data is used to indicate the change of the total pressure generated by the superposition of the expansion pressure and the gas production pressure of the target battery with the number of charge and discharge cycles.

[0070] In one example, the first parameter change data and the second parameter change data include first parameter change data and second parameter change data under a certain operating environment; accordingly, based on the first parameter change data and the second parameter change data, the total change data is determined, including:

[0071] For each charge-discharge cycle, the expansion pressure corresponding to the change in the first parameter and the gas production pressure corresponding to the change in the second parameter are added together to obtain the total change data. For example: Reference Figure 2 Add the expansion pressure and gas production pressure corresponding to the same number of charge-discharge cycles in expansion pressure curve 201 and gas production pressure curve 202 to obtain the total change data 203.

[0072] In another example, the first parameter change data and the second parameter change data include the first parameter change data and the second parameter change data corresponding to each of multiple operating environments; accordingly, based on the first parameter change data and the second parameter change data, the total change data is determined, including:

[0073] The maximum expansion pressure corresponding to each charge-discharge cycle is determined from the first parameter change data corresponding to various operating environments, and the maximum gas production pressure corresponding to each charge-discharge cycle is determined from the second parameter change data corresponding to various operating environments. The maximum expansion pressure and the maximum gas production pressure corresponding to each charge-discharge cycle are added together to obtain the total pressure corresponding to the number of charge-discharge cycles, thus obtaining the total change data.

[0074] For example, for the first charge-discharge cycle, from the first parameter variation data of 10 operating environments, it is determined that the gas production pressure is the highest in the third operating environment and the expansion pressure is the highest in the fifth operating environment. Then, the gas production pressure of the third operating environment and the expansion pressure of the fifth operating environment are added together to obtain the total pressure corresponding to the first charge-discharge cycle. Subsequent charge-discharge cycles are processed similarly to obtain the total variation data.

[0075] Step 103: Apply pressure k+1 times to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data.

[0076] In this embodiment, the casing of the target battery refers to the casing of the inner core of the target battery.

[0077] Optionally, based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, pressure is applied to the casing of the target battery k+1 times, including:

[0078] Determine the maximum total pressure corresponding to the total pressure from the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply pressure to the target battery casing k+1 times to produce the maximum total pressure; or, determine the average total pressure corresponding to the total pressure from the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply pressure to the target battery casing k+1 times to produce the average total pressure.

[0079] Taking the application of pressure k times to the target battery casing to achieve the maximum total pressure as an example, referring to Table 1 below, assuming k=49, since the gas generation pressure and expansion pressure generally increase gradually with the number of charge-discharge cycles, when i=1, from the 1st to the 50th charge-discharge cycle, the gas generation pressure A1 and expansion pressure B1 are at their maximum corresponding to the 50th charge-discharge cycle. Correspondingly, the total pressure A1+B1 corresponding to the 50th charge-discharge cycle is at its maximum. Based on the maximum total pressure A1+B1, pressure is applied to the target battery casing 50 times to test the target battery. When i=51, from the 51st to the 100th charge-discharge cycle, the gas generation pressure A2 and expansion pressure B2 are at their maximum corresponding to the 100th charge-discharge cycle; correspondingly, the total pressure A2+B2 corresponding to the 100th charge-discharge cycle is at its maximum. Based on the maximum total pressure A2+B2, pressure is applied to the target battery casing 50 times.

[0080] Table 1:

[0081]

[0082] Optionally, Table 1 uses a fixed value of 49 as an example for illustration. In other embodiments, k can also be a dynamic value. In this case, before applying pressure k times to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, the following steps are also included:

[0083] Determine the preset value range to which the value of i belongs; obtain the value of k corresponding to the preset value range.

[0084] The preset numerical intervals are at least two numerical intervals obtained by dividing the range of charge-discharge cycle counts into intervals. Different preset numerical intervals correspond to different k values. For example, the test objective of the battery casing is to test the fatigue test results of the battery casing after [1, 2000] charge-discharge cycle counts. Therefore, [1, 2000] can be divided into at least two preset numerical intervals, such as [1, 1000] and (1001, 2000]. The preset numerical interval [1, 1000] corresponds to k=k1; the preset numerical interval (1001, 2000] corresponds to k=k2. k1 and k2 are different.

[0085] Optionally, the preset numerical range includes a first numerical range and a second numerical range. The rate of change of total pressure corresponding to each charge-discharge cycle in the first numerical range is greater than the rate of change of total pressure corresponding to each charge-discharge cycle in the second numerical range. Accordingly, k corresponding to the first numerical range is less than k corresponding to the second numerical range.

[0086] The rate of change of total pressure corresponding to each preset value interval refers to the average value of the change in total pressure corresponding to two adjacent charge-discharge cycles within that preset value interval.

[0087] In this embodiment, by setting the rate of change of total pressure to be negatively correlated with the value of k, a smaller k value is used during the rapid change phase of total pressure to avoid missing important total pressure during the test, which could lead to inaccurate fatigue testing and improve test accuracy. A larger k value is used during the slow change phase of total pressure to avoid using too much redundant data for testing and to save test resources.

[0088] It should be noted that "first numerical interval" and "second numerical interval" are only used to distinguish different preset numerical intervals, and do not limit the number of preset numerical intervals. For example, there can be at least 3 preset numerical intervals, and any two of the at least 3 preset numerical intervals can be used as the first numerical interval and the second numerical interval to set the k value.

[0089] When applying pressure k+1 times to the casing of the target battery, the casing of the inner core of the target battery needs to be limited, and then the inner core after being limited is subjected to pressure k+1 times.

[0090] Step 104: If the casing after pressure application meets the preset requirements and i does not reach the preset value, let i = i + k + 1. Trigger the execution of the step of applying pressure to the casing of the target battery k + 1 times based on the total pressure corresponding to the i-th to i+k-th charge-discharge cycles indicated by the total change data, and the subsequent steps, until i reaches the preset value or the casing after pressure application does not meet the preset requirements, and stop to obtain the test result. Here, i is a positive integer starting from 1, and k is a positive integer.

[0091] For example, the test stops when i reaches a preset value or when the housing fails to meet preset requirements after pressure is applied, and the test results are obtained, including:

[0092] If the casing meets the preset requirements after pressure is applied and i reaches the preset value, the test result is determined to be that the casing of the target battery is qualified; if the casing does not meet the preset requirements after pressure is applied, the test result is determined to be that the casing of the target battery is unqualified.

[0093] The preset value can be the upper limit of the range of charge-discharge cycle counts mentioned above; or it can be other values ​​that are less than the upper limit of the range. The preset value can be 1000, 2000, 5000, etc. This embodiment does not limit the value of the preset value.

[0094] For example, the preset requirements include, but are not limited to, the battery cell casing being undamaged, or the degree of cracking of the battery cell casing being less than a preset degree. This embodiment does not limit the implementation method of the preset requirements.

[0095] In summary, the battery casing testing method provided in this embodiment acquires first parameter change data and second parameter change data of the target battery to be tested. The first parameter change data indicates the change in the expansion pressure of the target battery with the number of charge-discharge cycles; the second parameter change data indicates the change in the gas generation pressure of the target battery with the number of charge-discharge cycles. Based on the first and second parameter change data, total change data is determined. The total change data indicates the change in the total pressure generated by the superposition of the expansion pressure and the gas generation pressure of the target battery with the number of charge-discharge cycles. Based on the total pressure corresponding to the i-th to i+k-th charge-discharge cycles indicated by the total change data, k+1 pressures are applied to the casing of the target battery. If the pressurized casing meets the preset requirements and i does not reach the preset value, then i = i + k + 1, triggering the execution of the step of applying pressure to the target battery casing k + 1 times based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, and subsequent steps, until i reaches the preset value or the pressurized casing does not meet the preset requirements, and then stopping to obtain the test results. This can solve the problem that traditional casing testing methods cannot determine the fatigue load caused by cyclic pressure, thus leading to inaccurate battery casing test results. Since it can test the target battery's ability to withstand gas generation pressure and cyclic pressure, and obtain the fatigue test results of the target battery, it can improve the accuracy of the strength test results of the battery cell casing.

[0096] In addition, by adding the maximum expansion pressure and the maximum gas production pressure corresponding to each charge-discharge cycle, the total pressure corresponding to the charge-discharge cycle can be obtained. The most stringent pressure data can be used to conduct fatigue tests on the shell strength, ensuring the strength of the shell that passes the test.

[0097] In addition, by setting the rate of change of total pressure to be negatively correlated with the value of k, a smaller k value can be used during the rapid change phase of total pressure to avoid missing important total pressure during the test, which would lead to inaccurate fatigue testing and improve test accuracy. A larger k value can be used during the slow change phase of total pressure to avoid using too much redundant data for testing and to save test resources.

[0098] Figure 3 A block diagram of a testing apparatus for a battery casing according to an embodiment of the present disclosure is shown. Figure 3 It is known that the device includes: a data acquisition module 310, a data processing module 320, a pressure testing module 330, and a result acquisition module 340.

[0099] The data acquisition module 310 is used to acquire first parameter change data and second parameter change data of the target battery to be tested; wherein, the first parameter change data is used to indicate the change of the expansion pressure of the target battery with the number of charge-discharge cycles; and the second parameter change data is used to indicate the change of the gas generation pressure of the target battery with the number of charge-discharge cycles.

[0100] Data processing module 320 is used to determine total change data based on the first parameter change data and the second parameter change data; the total change data is used to indicate the change of the total pressure generated by the superposition of the expansion pressure and the gas production pressure of the target battery with the number of charge and discharge cycles;

[0101] The pressure testing module 330 is used to apply k+1 pressures to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data.

[0102] The result acquisition module 340 is used to, when the casing after pressure is applied meets the preset requirements and i does not reach the preset value, set i = i + k + 1, trigger the execution of the step of applying pressure to the casing of the target battery k+1 times based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data, and the subsequent steps, until i reaches the preset value or the casing after pressure is applied does not meet the preset requirements, and then stop to obtain the test result; where i is a positive integer starting from 1, and k is a positive integer.

[0103] Optionally, the data acquisition module 310 is used for:

[0104] A finite element model of the target battery is established based on its structure;

[0105] Expansion force simulation was performed based on the finite element model to obtain the first parameter variation data under each operating environment.

[0106] Optionally, the data acquisition module 310 is used for:

[0107] Based on the chemical reactions that occur in the target battery during charging and discharging, the change data of the second parameter corresponding to the chemical reactions under each operating environment are determined.

[0108] Optionally, the first parameter change data and the second parameter change data include first parameter change data and second parameter change data corresponding to each operating environment under multiple operating environments;

[0109] Accordingly, the data processing module 320 is used for:

[0110] The maximum expansion pressure corresponding to each charge-discharge cycle is determined from the first parameter change data corresponding to various operating environments, and the maximum gas production pressure corresponding to each charge-discharge cycle is determined from the second parameter change data corresponding to various operating environments.

[0111] The maximum expansion pressure and the maximum gas production pressure corresponding to each charge-discharge cycle are added together to obtain the total pressure corresponding to the number of charge-discharge cycles, thus obtaining the total change data.

[0112] Optionally, the pressure testing module 330 is used for:

[0113] Determine the maximum total pressure value corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply k+1 pressures to the casing of the target battery to generate the maximum total pressure value;

[0114] or,

[0115] Determine the average total pressure corresponding to the total pressure from the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle; apply k+1 pressures to the casing of the target battery that can generate the average total pressure.

[0116] Optionally, the device further includes an interval determination module and a k-value determination module.

[0117] The interval determination module is used to determine the preset value interval to which the value of i belongs before applying pressure k times to the casing of the target battery based on the total pressure corresponding to the i-th charge-discharge cycle to the (i+k)-th charge-discharge cycle indicated by the total change data.

[0118] The k-value determination module is used to obtain the value of k corresponding to the preset numerical range;

[0119] The preset numerical range is at least two numerical ranges obtained by dividing the range of the number of charge-discharge cycles into intervals, and different preset numerical ranges correspond to different k values.

[0120] Optionally, the preset numerical range includes a first numerical range and a second numerical range. The rate of change of total pressure corresponding to each charge-discharge cycle in the first numerical range is greater than the rate of change of total pressure corresponding to each charge-discharge cycle in the second numerical range. Accordingly, k corresponding to the first numerical range is less than k corresponding to the second numerical range.

[0121] Optionally, the result acquisition module 340 is used for:

[0122] If the casing reaches the preset requirements after pressure is applied and i reaches the preset value, the test result is determined to be that the casing of the target battery is qualified.

[0123] If the casing does not meet the preset requirements after pressure is applied, the test result is determined to be that the casing of the target battery is unqualified.

[0124] In some embodiments, the functions or modules of the apparatus provided in this disclosure can be used to perform the methods described in the above method embodiments. The specific implementation can be referred to the description of the above method embodiments, and for the sake of brevity, it will not be repeated here.

[0125] This disclosure also provides a battery casing testing apparatus, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the above method.

[0126] This disclosure also provides a non-volatile computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the above-described method.

[0127] This disclosure also provides a computer program product, including a computer program or a non-volatile computer-readable storage medium carrying the computer program, wherein the computer program, when executed by a processor, implements the steps of the above method.

[0128] Figure 4 This is a block diagram illustrating a battery casing testing apparatus 1900 according to an exemplary embodiment. For example, apparatus 1900 can be provided as a server or terminal device. (Refer to...) Figure 4 The apparatus 1900 includes a processing component 1922, which further includes one or more processors, and memory resources represented by memory 1932 for storing instructions, such as application programs, that can be executed by the processing component 1922. The application programs stored in memory 1932 may include one or more modules, each corresponding to a set of instructions. Furthermore, the processing component 1922 is configured to execute instructions to perform the methods described above.

[0129] Device 1900 may also include a power supply component 1926 configured to perform power management of device 1900, a wired or wireless network interface 1950 configured to connect device 1900 to a network, and an input / output interface 1958 (I / O interface). Device 1900 can operate on an operating system, such as Windows Server, stored in memory 1932. TM macOS X TM Unix TM Linux TM FreeBSD TM Or similar.

[0130] In an exemplary embodiment, a non-volatile computer-readable storage medium is also provided, such as a memory 1932 including computer program instructions that can be executed by a processing component 1922 of the device 1900 to perform the above-described method.

[0131] Computer-readable storage media can be tangible devices capable of holding and storing programs / instructions used by instruction execution devices. Computer-readable storage media can be, for example—but not limited to—electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of computer-readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination of the foregoing. The computer-readable storage media used herein are not to be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses through fiber optic cables), or electrical signals transmitted through wires.

[0132] The computer program (or computer-readable program instructions) described herein can be downloaded from a computer-readable storage medium to various computing / processing devices, or downloaded via a network, such as the Internet, local area network, wide area network, and / or wireless network, to an external computer or external storage device. The network may include copper transmission cables, fiber optic transmission, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to the computer-readable storage medium in the respective computing / processing device.

[0133] The computer program (or computer program instructions) used to perform the operations of this disclosure may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk, C++, etc., and conventional procedural programming languages ​​such as the "C" language or similar programming languages. The computer-readable program instructions may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving a remote computer, the remote computer may be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry, such as programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), is personalized by utilizing state information from the computer-readable program instructions to implement various aspects of this disclosure.

[0134] Various aspects of this disclosure are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0135] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that, when executed by the processor of the computer or other programmable data processing apparatus, they create means for implementing the functions / actions specified in one or more blocks of the flowchart and / or block diagram. These computer-readable program instructions can also be stored in a computer-readable storage medium that causes a computer, programmable data processing apparatus, and / or other device to operate in a particular manner; thus, the computer-readable medium storing the instructions comprises an article of manufacture that includes instructions for implementing aspects of the functions / actions specified in one or more blocks of the flowchart and / or block diagram.

[0136] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0137] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0138] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method of testing a battery case, characterized by, The method comprises: obtaining first parameter change data and second parameter change data of a target battery to be tested; wherein the first parameter change data is used to indicate the change of the expansion pressure of the target battery with the number of charge-discharge cycles; and the second parameter change data is used to indicate the change of the gas generation pressure of the target battery with the number of charge-discharge cycles; determining total change data based on the first parameter change data and the second parameter change data; wherein the total change data is used to indicate the change of the total pressure of the target battery with the number of charge-discharge cycles, which is the superposition of the expansion pressure and the gas generation pressure; applying k+1 times of pressure to the shell of the target battery based on the total pressure corresponding to the i th charge-discharge cycle to the i+k th charge-discharge cycle indicated by the total change data; in the case that the shell after the pressure application meets the preset requirement and i does not reach the preset value, setting i=i+k+1, triggering the step of applying k+1 times of pressure to the shell of the target battery based on the total pressure corresponding to the i th charge-discharge cycle to the i+k th charge-discharge cycle indicated by the total change data and the subsequent steps until the i reaches the preset value or the shell after the pressure application does not meet the preset requirement, thereby obtaining a test result; wherein i is a positive integer starting from 1, and k is a positive integer.

2. The method of claim 1, wherein, The first parameter change data of the target battery to be tested is obtained, comprising: establishing a finite element model of the target battery based on the structure of the target battery; obtaining the first parameter change data under each operating environment through expansion force simulation based on the finite element model.

3. The method of claim 1, wherein, The second parameter change data of the target battery to be tested is obtained, comprising: determining the second parameter change data corresponding to the chemical reaction under each operating environment based on the chemical reaction occurring when the target battery is charged and discharged.

4. The method of claim 1, wherein, The first parameter change data and the second parameter change data comprise the first parameter change data and the second parameter change data corresponding to each operating environment under multiple operating environments; Correspondingly, the determination of the total change data based on the first parameter change data and the second parameter change data comprises: determining the maximum expansion pressure corresponding to each charge-discharge cycle from the first parameter change data corresponding to each operating environment, and determining the maximum gas generation pressure corresponding to each charge-discharge cycle from the second parameter change data corresponding to each operating environment; adding the maximum expansion pressure corresponding to each charge-discharge cycle and the maximum gas generation pressure corresponding to each charge-discharge cycle to obtain the total pressure corresponding to the charge-discharge cycle, thereby obtaining the total change data.

5. The method of claim 1, wherein, The application of k times of pressure to the shell of the target battery based on the total pressure corresponding to the i th charge-discharge cycle to the i+k th charge-discharge cycle indicated by the total change data comprises: determining the maximum total pressure corresponding to the total pressure of the i th charge-discharge cycle to the i+k th charge-discharge cycle; and applying k+1 times of pressure to the shell of the target battery, which can generate the maximum total pressure; or determining a total pressure average of total pressures corresponding to the i th to i+k th charge-discharge cycles; and applying a pressure to the shell of the target battery, the pressure being capable of generating the total pressure average.

6. The method of claim 1, wherein, Before the applying of the k times of pressure to the shell of the target battery based on the total pressure corresponding to the i th to i+k th charge-discharge cycles indicated by the total change data, the method further comprises: determining a preset numerical interval to which a value of i belongs; obtaining a value of k corresponding to the preset numerical interval; wherein the preset numerical interval is at least two numerical intervals obtained by interval division on a value range of the charge-discharge cycle number, and the value of k corresponding to different preset numerical intervals is different.

7. The method of claim 6, wherein, The preset numerical interval includes a first numerical interval and a second numerical interval, a change rate of the total pressure corresponding to each charge-discharge cycle number in the first numerical interval is greater than a change rate of the total pressure corresponding to each charge-discharge cycle number in the second numerical interval, and correspondingly, the k corresponding to the first numerical interval is less than the k corresponding to the second numerical interval.

8. The method according to any one of claims 1 to 7, characterized in that, The i reaches a preset value or the shell after the applying of the pressure does not meet a preset requirement, and a test result is obtained, including: In a case that the shell after the applying of the pressure meets the preset requirement and the i reaches the preset value, it is determined that the test result is that the shell of the target battery is qualified. In a case that the shell after the applying of the pressure does not meet the preset requirement, it is determined that the test result is that the shell of the target battery is unqualified.

9. A testing device for battery casings, comprising a memory, a processor and a computer program stored on the memory, characterized in that, The processor executes the computer program to implement the steps of the method in any one of claims 1 to 8.

10. A non-transitory computer readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to implement the steps of the method in any one of claims 1 to 8.

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