Nail penetration test method and device

Abstract

A nail penetration test method and device, which can improve the nail penetration test performance. The method comprises: controlling a penetrating nail to move towards the direction where the penetrating nail is penetrated into a battery cell; and when the voltage between the penetrating nail and a first electrode terminal of the battery cell exceeds a preset voltage, continuing controlling the penetrating nail to penetrate into a predetermined depth.

Description

Acupuncture test method and device

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application 202311449327.2, filed on November 2, 2023, entitled “Method and Apparatus for Acupuncture Testing,” the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of batteries, and in particular to a method and device for a needle penetration test. Background Art

[0004] Battery penetration testing, also known as internal short-circuit testing, is used to assess the safety risks of battery cells when an internal short circuit occurs. Typically, a probe is inserted into the battery cell to assess the safety risk caused by a short circuit between the electrode and the probe. Improving the performance of the penetration test has become a pressing issue.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a method and apparatus for a needle prick test, which can improve the performance of the needle prick test.

[0007] In a first aspect, a method for a needle penetration test is provided, the method comprising: controlling a needle to move in a direction of penetrating a battery cell; and continuing to control the needle to penetrate a predetermined depth when a voltage between the needle and a first electrode terminal of the battery cell exceeds a preset voltage.

[0008] Optionally, the battery cell includes a first pole piece and a second pole piece that are overlapped, and the pole piece located on the outermost layer is the second pole piece, the first electrode terminal is an electrode terminal connected to the first pole piece, and the polarity of the first pole piece is opposite to that of the second pole piece.

[0009] As the needle moves toward the battery cell, it detects the voltage between the first electrode terminal connected to the first electrode sheet. This voltage changes significantly when the needle touches or punctures the outermost second electrode sheet. Therefore, in the embodiment of the present application, the position of the needle at the moment the voltage exceeds the preset voltage is used as the starting point of the needle's penetration on the battery cell, that is, the position when the needle touches or punctures the outermost second electrode sheet. This starting point is used as the starting point to control the needle's continued movement within the battery cell to a predetermined depth. In this way, without the need for complex modifications to the battery cell, the relationship between the physical structure of the battery cell and the voltage can be utilized to accurately and conveniently complete the needle penetration test, while improving test accuracy and meeting different testing requirements.

[0010] In a possible implementation, the predetermined depth is determined according to the number of electrode layers that need to be penetrated in the needle penetration test.

[0011] In practical applications, the need for needle penetration testing is usually characterized by the number of layers, that is, how many layers of electrode need to be penetrated. By converting the number of layers of electrode that need to be penetrated into the penetration depth, the desired test requirements can be achieved through the above-mentioned needle penetration test method.

[0012] In a possible implementation, the predetermined depth is determined according to the number of layers, the thickness of the first pole piece, and the thickness of the second pole piece.

[0013] In this embodiment, the number of penetration layers and the penetration depth can be converted according to the desired number of penetration layers and the thickness of the electrode. For example, the predetermined depth is determined according to the number of layers, the thickness of the first electrode, and the thickness of the second electrode.

[0014] In one possible implementation, the predetermined depth is determined based on the number of layers, the thickness of the first pole piece, the thickness of the second pole piece, and the thickness of the isolation membrane between the first pole piece and the second pole piece and / or a preset gap value.

[0015] By taking into account the thickness of the separator between the first and second pole pieces, or by setting a preset gap value, the accuracy of the conversion between the number of layers and the depth can be improved. The stack of the first and second pole pieces has a certain degree of looseness, and when the needle penetrates the battery cell, it presses the pole pieces in the penetration area. This gap value can compensate for this to a certain extent, thereby improving test accuracy.

[0016] For example, when the number of layers is 1, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D; and / or, when the number of layers is N, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), N is a positive integer greater than 1; wherein A is the thickness of the first pole piece, C is the thickness of the second pole piece, S is the thickness of the isolation membrane, and D is the gap value.

[0017] The preset voltage is, for example, greater than or equal to 0.5V and less than or equal to 1.5V. Preferably, the preset voltage is 1V. If the preset voltage is large, the test accuracy will be relatively poor. If the preset voltage is small, higher requirements are placed on the sensitivity of the test device. To this end, after repeated experimental verification, when the preset voltage is within the range of 0.5V to 1.5V, the deviation of the starting insertion position is within the thickness of one electrode layer, which can meet the testing requirements of most battery cells.

[0018] In one possible implementation, the battery cell further includes a housing for accommodating the first and second pole pieces, and a clearance hole is provided on the housing at a position for the needle to penetrate. The clearance hole can effectively avoid the needle, thereby facilitating the needle's penetration into the pole pieces.

[0019] In one possible implementation, the method further includes controlling the battery cells to be charged to a predetermined SOC and to rest for a predetermined period of time. Charging the battery cells to the predetermined SOC and resting them allows the battery cells to be in a stable state to improve their performance in the needle penetration test.

[0020] In a second aspect, a device for a needle penetration test is provided, which includes: a processing module for controlling the movement of a needle in a direction of penetrating a battery cell; a detection module for detecting the voltage between the needle and the first electrode terminal of the battery cell during the movement of the needle; the processing module is also used to continue controlling the needle to penetrate a predetermined depth when the voltage between the needle and the first electrode terminal of the battery cell exceeds a preset voltage.

[0021] Optionally, the battery cell includes a first pole piece and a second pole piece that are overlapped, and the pole piece located on the outermost layer is the second pole piece, the first electrode terminal is an electrode terminal connected to the first pole piece, and the polarity of the first pole piece is opposite to that of the second pole piece.

[0022] In a possible implementation, the predetermined depth is determined according to the number of electrode layers that need to be penetrated in the needle penetration test.

[0023] In a possible implementation, the predetermined depth is determined according to the number of layers, the thickness of the first pole piece, and the thickness of the second pole piece.

[0024] In one possible implementation, the predetermined depth is determined based on the number of layers, the thickness of the first pole piece, the thickness of the second pole piece, and the thickness of the isolation membrane between the first pole piece and the second pole piece and / or a preset gap value.

[0025] In a possible implementation, when the number of layers is 1, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D; and / or, when the number of layers is N, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), N is a positive integer greater than 1; wherein A, C, S and D are the thickness of the first pole piece, the thickness of the second pole piece, the thickness of the isolation membrane, and the gap value, respectively.

[0026] In a possible implementation, the preset voltage is greater than or equal to 0.5V and less than or equal to 1.5V, for example, may be 1V.

[0027] In a possible implementation, the battery cell further includes a shell, the shell being used to accommodate the first pole piece and the second pole piece, and an avoidance hole is provided on the shell at a position for the puncture needle to penetrate.

[0028] In a possible implementation, the processing module is further configured to control the battery cells to be charged to a predetermined SOC.

[0029] In a third aspect, a device for a pinpoint test is provided, comprising a processor configured to execute computer instructions stored in a memory so that the device implements the pinpoint test method described in the first aspect or any possible implementation of the first aspect.

[0030] In a fourth aspect, a computer-readable storage medium is provided for storing a computer program, which, when executed by a computing device, enables the computing device to implement the acupuncture test method described in the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0032] Figure 1 is a schematic diagram of the needle penetration test.

[0033] FIG2 is a schematic diagram of the initial insertion position of the needle stick test.

[0034] FIG3 is a schematic flow chart of a method for acupuncture testing according to an embodiment of the present application.

[0035] FIG4 is a schematic diagram of a possible electrode stack of a battery cell according to an embodiment of the present application.

[0036] FIG5 is a schematic diagram showing the changes in the interface between the electrode and the needle during the insertion of the needle.

[0037] FIG6 is a schematic diagram of an equivalent circuit between a needle and a positive electrode terminal.

[0038] FIG. 7 is a schematic diagram of a possible specific implementation of the acupuncture test method shown in FIG. 3 .

[0039] FIG8 is a schematic flow chart of a possible specific implementation of the acupuncture test method shown in FIG3 .

[0040] FIG9 is a schematic block diagram of a device for acupuncture testing according to an embodiment of the present application.

[0041] FIG10 is a schematic block diagram of a device for acupuncture testing according to an embodiment of the present application. DETAILED DESCRIPTION

[0042] The following detailed description of the embodiments of the present application is provided in conjunction with the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present application, but are not intended to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0043] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application 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. The terms "first", "second", etc. in the specification and claims or drawings of this application are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. "Vertical" is not strictly perpendicular, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0044] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0045] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "attached" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0046] The term "and / or" in this application simply describes an association between related objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this application generally indicates that the related objects are in an "or" relationship.

[0047] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are for illustrative purposes only and do not constitute any limitation on this application.

[0048] A battery generally refers to a single physical module that includes one or more battery cells to provide a higher voltage and capacity. For example, a battery can include a battery module or a battery pack. Batteries typically also include a casing that encloses the battery cells. This casing prevents liquids and other foreign matter from affecting the charging or discharging of the battery cells.

[0049] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly consists of a positive electrode sheet, a negative electrode sheet, and a separator located between the positive and negative electrode sheets. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the main body of the positive current collector. The portion of the positive current collector not coated with the positive active material layer protrudes from the main body of the positive current collector as the positive electrode tab. For lithium-ion batteries, for example, the positive current collector can be made of aluminum, and the positive active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the main body of the negative current collector. The portion of the negative current collector not coated with the negative active material layer protrudes from the main body of the negative current collector as the negative electrode tab. The negative current collector can be made of copper, and the negative active material can be carbon or silicon, among others. In order to reduce the probability of melting due to large current, the number of positive electrode tabs can be multiple and stacked together, and the number of negative electrode tabs can be multiple and stacked together.

[0050] To simulate an internal short circuit scenario caused by contamination of the battery by conductive particles, a needle with a diameter of approximately 1 mm can be used to penetrate the electrode of a battery cell, causing an internal short circuit in the battery cell. This can then assess the safety risk of the battery cell when an internal short circuit occurs. This process is commonly referred to as a needle penetration test, shallow penetration test, or internal short circuit test of the battery. It is understood that the penetration point of the needle on the electrode corresponds to the main part of the current collector coated with the active material layer on the electrode.

[0051] For example, as shown in FIG1 , the needle 10 is connected to the first electrode terminal 21 of the battery cell 20. The first electrode terminal 21 and the second electrode terminal 22 have opposite polarities. For example, the first electrode terminal 21 is a negative electrode terminal and the second electrode terminal 22 is a positive electrode terminal, or the first electrode terminal 21 is a positive electrode terminal and the second electrode terminal 22 is a negative electrode terminal. The battery cell 20 includes a positive electrode sheet and a negative electrode sheet arranged in an overlapping manner. If the positive electrode sheet is the outermost layer, the first electrode terminal 21 connected to the needle 10 is the negative electrode terminal; if the negative electrode sheet is the outermost layer, the first electrode terminal 21 connected to the needle 10 is the positive electrode terminal.

[0052] Taking the example of a battery cell 20 with the negative electrode tab at the outermost layer and the first electrode terminal 21 as the positive electrode terminal, the needle 10 is connected to the first electrode terminal 21. As the needle 10 moves toward the battery cell 20, before it touches or punctures the outermost negative electrode tab, no circuit is formed between the outermost negative electrode tab, the needle 10, the detection module 30, and the first electrode terminal 21. When the needle 10 touches or punctures the outermost negative electrode tab, a circuit is formed between the outermost negative electrode tab, the needle 10, the detection module 30, and the first electrode terminal 21, allowing the detection module 30 to detect the voltage between the positive and negative tabs. As the needle 10 continues to penetrate the interior of the battery cell 20, an internal short circuit is formed between the positive and negative tabs through the needle 10, allowing the detection module 30 to detect a voltage drop between the needle 10 and the first electrode terminal 21. At this time, the needle 10 stops moving, and it is considered that the needle 10 has penetrated the negative electrode sheet and the positive electrode sheet of the first layer of the battery cell 20 .

[0053] Typically, a needle penetration test requires that the needle 10 penetrate one layer of the positive and negative electrode sheets within the battery cell 20. The processing module 40 can determine whether the needle 10 has penetrated one layer of the positive and negative electrode sheets of the battery cell 20 based on the change in voltage between the needle 10 and the first electrode terminal 21 detected by the detection module 30.

[0054] However, in other scenarios, it is also desirable to penetrate the multiple layers of positive and negative electrode sheets within the battery cell 20. Because the positive and negative electrode sheets are stacked and thus have a certain degree of looseness, as shown in FIG2 , when the needle 10 penetrates the interior of the battery cell 20, it compresses the electrode sheets 23 in the area near the penetration position. Therefore, there is a deviation between the theoretical starting position A of the needle on the battery cell 20 and the actual starting penetration position B of the needle 10 on the battery cell 20. Since the starting position B of the needle 10 cannot be accurately determined, it is impossible to identify the voltage drop generated when the multiple layers of positive and negative electrode sheets are short-circuited by the needle 10, and thus it cannot adapt to more testing requirements.

[0055] To this end, this application proposes a needle penetration test scheme, which aims to use the relationship between the physical structure and voltage of the battery cell to determine the starting penetration position of the needle on the battery cell, and then control the penetration depth or number of layers of the needle in the battery cell based on the starting penetration position, so as to meet different testing requirements.

[0056] As an example, FIG3 shows a schematic flow chart of the method for the puncture test of an embodiment of the present application. The battery cells to be tested may include, for example, secondary batteries such as sodium ion batteries and lithium ion batteries, whose structure includes a first pole piece and a second pole piece arranged in an overlapping manner, and the pole piece located on the outermost layer is the second pole piece, and the polarity of the first pole piece and the second pole piece are opposite. The method 100 can be applied to the puncture test of battery cells 20 of various structural types. The battery cell 20 can be a winding structure, a laminated structure, a cylindrical battery cell or a soft-pack battery cell. These battery cells can all be tested using the method 100 for the puncture test provided in the embodiment of the present application.

[0057] As shown in FIG3 , method 100 includes some or all of the following steps.

[0058] In step 110 , the puncture needle 10 is controlled to move in a direction of puncturing the battery cell 20 .

[0059] In step 120 , when the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds the preset voltage, the needle 10 is continuously controlled to penetrate to a predetermined depth.

[0060] Optionally, the battery cell 20 includes a first pole piece and a second pole piece that are overlapped, and the pole piece located on the outermost layer is the second pole piece. The first electrode terminal is the electrode terminal on the battery cell 20 connected to the first pole piece, and the polarity of the first pole piece is opposite to that of the second pole piece.

[0061] The positive electrode sheet of the battery cell 20 is connected to the positive electrode terminal, and the negative electrode sheet is connected to the negative electrode terminal. When the outermost electrode sheet of the battery cell 20 is configured as the negative electrode sheet, the needle 10 can be connected to the positive electrode terminal of the battery cell 20 to detect the voltage between the needle 10 and the positive electrode terminal during the movement of the needle 10 toward the battery cell 20. The voltage between the needle 10 and the positive electrode terminal is the voltage between the needle 10 and the total positive of the battery cell 20; when the outermost electrode sheet of the battery cell 20 is configured as the positive electrode sheet, the needle 10 can be connected to the negative electrode terminal of the battery cell 20 to detect the voltage between the needle 10 and the negative electrode terminal during the movement of the needle 10 toward the battery cell 20. The voltage between the needle 10 and the negative electrode terminal is the voltage between the needle 10 and the total negative of the battery cell 20.

[0062] The phrase "when the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds a preset voltage" in step 120 may refer to, for example, the moment when the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds the preset voltage. Specifically, as the needle 10 moves toward the battery cell 20, the voltage between the needle 10 and the first electrode terminal of the battery cell 20 needs to be detected, and the position of the needle 10 at the moment when the voltage between the needle 10 and the first electrode terminal exceeds the preset voltage is used as the starting insertion position of the needle 10 on the battery cell 20. Based on this starting insertion position, the needle 10 is inserted into the battery cell 20 to a predetermined depth. The predetermined depth is the distance the needle 10 moves within the battery cell 20, that is, the depth to which the needle 10 penetrates the battery cell 20.

[0063] The voltage between the needle 10 and the first electrode terminal of the battery cell 20 can be detected by a detection module 30 connected between the needle 10 and the first electrode terminal of the battery cell 20. The detection module 30 can include a voltage detection device such as a voltmeter or a voltage acquisition card.

[0064] The starting insertion position refers to the position of the needle 10 when it begins to penetrate the battery cell 20. At this point, the needle 10 may touch or slightly penetrate the outermost second electrode sheet. In other words, the starting insertion position can be considered the position of the needle 10 when it touches or penetrates the outermost second electrode sheet. For example, it can be the position of the needle tip, the needle tail, or other part of the needle 10. The needle 10 can then be controlled to continue moving from this starting insertion position until it penetrates the battery cell 20 to a predetermined depth. Here, the step of controlling the needle 10 includes directly or indirectly controlling the needle 10, i.e., directly controlling the needle 10 to penetrate the battery cell 20 to a predetermined depth from the starting insertion position; or controlling a clamping device for clamping the needle 10 to cause the needle 10 to penetrate the battery cell 20 to a predetermined depth from the starting insertion position.

[0065] As the needle 10 moves toward the battery cell 20, it detects the voltage between the needle 10 and the first electrode terminal. When the needle 10 touches or punctures the outermost second electrode sheet, a circuit is formed between the outermost second electrode sheet, the needle 10, the detection module 30, and the first electrode terminal 21, causing the voltage between the needle 10 and the first electrode terminal 21 to change. Therefore, the present embodiment determines the moment when the voltage between the needle 10 and the first electrode terminal exceeds a preset voltage, and the position to which the needle 10 moves at that moment, as the starting insertion position. Using this starting insertion position as a starting point, the needle 10 is controlled to continue moving within the battery cell 20 to a predetermined depth. This allows the needle to determine the starting insertion position within the battery cell 20 without requiring complex modifications to the battery cell 20. By leveraging the relationship between the physical structure of the battery cell 20 and its voltage, the starting insertion position can be determined, enabling needle penetration testing of a predetermined number of layers or depth within the battery cell 20, meeting testing requirements for different penetration levels and depths.

[0066] The direction of piercing the battery cell 20 in step 110 can be, for example, a direction perpendicular to or approximately perpendicular to the electrode of the battery cell 20. In other words, the needle 10 can penetrate the electrode of the battery cell 20 in a perpendicular or approximately perpendicular direction, i.e., when the needle 10 moves toward the battery cell 20, the moving direction of the needle 10 is perpendicular to or approximately perpendicular to the surface of the electrode.

[0067] The need for a needle penetration test can be characterized by the number of layers. The need for a needle penetration test may be that the needle 10 is expected to penetrate multiple layers of positive and negative electrode sheets in the battery cell 20. Optionally, the predetermined depth in step 120 is associated with the number of layers of the electrode sheets that need to be penetrated in the needle penetration test. For example, different depths correspond to different numbers of layers. When the number of layers of the electrode sheets that are expected to be penetrated is N1, the predetermined depth is M1; when the number of layers of the electrode sheets that are expected to be penetrated is N2, the predetermined depth is M2; when the number of layers of the electrode sheets that are expected to be penetrated is N3, the predetermined depth is M3; and so on.

[0068] To this end, it is necessary to convert the number of electrode layers to be penetrated into the penetration depth, and then control the movement distance of the needle 10 based on the starting penetration position so that it penetrates to a predetermined depth within the battery cell 20. In this way, the desired test requirements can be achieved through the above-mentioned needle penetration test method.

[0069] Of course, if the needle penetration test requirement is characterized by depth, for example, the needle penetration test requirement may be to expect the needle 10 to penetrate a predetermined depth within the battery cell 20. Then, after determining the starting penetration position, the needle 10 can be controlled to move a corresponding distance based on the starting penetration position. For example, if the predetermined depth is 1.5 mm, the needle 10 can be controlled to move 1.5 mm starting from the starting penetration position. For another example, if the predetermined depth is 2 mm, the needle 10 can be controlled to move 2 mm starting from the starting penetration position.

[0070] Therefore, in some embodiments, method 100 further includes: determining the predetermined depth based on the number of electrode layers that need to be penetrated in the needle penetration test. In other words, the predetermined depth can be determined based on the number of electrode layers that need to be penetrated in the needle penetration test. It can be understood that the number of electrode layers described in the embodiments of the present application refers to the number of electrode layers formed by a first electrode and a second electrode, that is, each electrode layer includes a first electrode layer and a second electrode layer. In the case of considering an isolation membrane, each electrode layer may include a first electrode layer, a second electrode layer, and an isolation membrane layer or two isolation membrane layers.

[0071] The “penetration” described in the embodiments of the present application can be understood in a broad sense, and the penetration of the needle 10 into a certain electrode includes the needle 10 touching and / or piercing the electrode.

[0072] FIG4 is a schematic diagram of a possible electrode stack for a battery cell 20. As shown in FIG4 , a first electrode 231 and a second electrode 232 are arranged in an overlapping manner, with the outermost electrode being the second electrode 232. A separator 233 is disposed between the first electrode 231 and the second electrode 232, and an insulating layer 234 is also disposed on the outermost layer. As the needle 10 moves toward the battery cell 20, it first penetrates the outermost insulating layer 234 and the two separators 233, compressing the electrode sheets to a certain extent. It then touches or penetrates the outermost second electrode 232, detecting a voltage change between the first electrode terminal of the battery cell and the needle 10 during this process. The starting insertion position is determined based on this voltage change.

[0073] Based on this initial insertion position, the needle 10 continues to move and sequentially penetrates the first electrode layer, the second electrode layer, the third electrode layer, and so on. As an example, Figure 4 only shows three electrode layers, where the first electrode layer includes a first electrode layer 231, a second electrode layer 232, and an isolation film 233 between the two. Starting from the second electrode layer, each electrode layer includes a first electrode layer 231, a second electrode layer 232, and two isolation films 233, such as the second and third electrode layers shown in Figure 4.

[0074] It should be noted that the definition of the number of electrode layers in the embodiments of the present application is only an example and can be appropriately adjusted in actual applications. For example, the first electrode 231 is used as a single electrode layer, and the second electrode 232 is used as a single electrode layer. In this case, as shown in FIG4 , the first electrode layer includes a second electrode 232, the second electrode layer includes a first electrode 231 and an isolation film 233, the third electrode layer includes a second electrode 232 and an isolation film, and so on.

[0075] Optionally, the predetermined depth in step 120 is associated with the thickness of the first pole piece and the thickness of the second pole piece of the battery cell. Furthermore, the predetermined depth may also be associated with the thickness of the first pole piece and the thickness of the second pole piece of the battery cell, as well as the thickness of the separator between the first pole piece and the second pole piece and / or a predetermined gap value.

[0076] In some embodiments, the predetermined depth may be determined based on the number of electrode layers that need to be penetrated in the needle penetration test, the thickness of the first electrode 231 , and the thickness of the second electrode 232 .

[0077] Furthermore, in other embodiments, the predetermined depth can be determined based on the number of electrode layers that need to be penetrated in the needle penetration test, the thickness of the first electrode 231, the thickness of the second electrode 232, and the thickness of the isolation membrane 233 between the first electrode 231 and the second electrode 232 and / or the preset gap value D.

[0078] That is to say, according to the desired number of penetration layers and the thickness of the electrode, the number of penetration layers and the penetration depth are converted. For example, according to the desired number of penetration layers of the electrode, the thickness of the first electrode 231 and the thickness of the second electrode 232, and the thickness of the isolation membrane 233 between the first electrode 231 and the second electrode 232 and / or the preset gap value D, the desired predetermined penetration depth is determined.

[0079] Alternatively, when the number of electrode layers to be penetrated is one, that is, it is desired to penetrate one first electrode 231 and one second electrode 232, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D. Where A is the thickness of the first electrode 231, C is the thickness of the second electrode 232, S is the thickness of the isolation film 233, and D is the gap value.

[0080] For example, the above-mentioned depth range can be mapped based on data such as the first electrode 231, the second electrode 232, the isolation membrane 233 or the number of layers to be penetrated of the battery cell 20, and any value within the depth range can be selected as the predetermined depth, for example, the middle value within the depth range can be selected.

[0081] Alternatively, when the number of electrode layers to be penetrated is N, that is, it is desired to penetrate N layers of first electrode pieces 231 and N layers of second electrode pieces 232, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), where N is a positive integer greater than 1.

[0082] Because the first electrode piece 231 and the second electrode piece 232 of the battery cell 20 are compacted to different degrees after overlapping, a certain gap exists between the electrode pieces. The size of the gap D can be determined, for example, based on the manufacturing process. When the needle 10 penetrates the battery cell 20, it compresses the electrode pieces in the penetration area. This gap D can compensate for this, thereby improving test accuracy.

[0083] For example, if one electrode layer needs to be penetrated, the penetration depth L1 of the needle 10 in the battery cell 20 can be in the range of C+S+D to A+C+S+D; if two electrode layers need to be penetrated, the penetration depth L2 of the needle 10 in the battery cell 20 can be in the range of (A+C+S+D)+(C+2S) to (A+C+S+D)+(A+C+2S); ...; if N ...1 of the needle 10 in the battery cell 20 can be in the range of (A+C+S+D)+(C+2S) to (A+C+S+D)+(A+C+2S). NIt can be in the range of (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S) to (A+C+S+D)+(A+C+2S)*(N-1). In this way, the first electrode piece 231 and the second electrode piece 232 in each layer of electrode pieces can be short-circuited, thereby achieving an internal short circuit at the corresponding position in the battery cell 20.

[0084] Taking the case where one electrode layer, i.e., the first electrode layer, needs to be penetrated as an example, as shown in FIG4 , the first electrode layer includes, from top to bottom, the second electrode 232, the isolation membrane 233, and the first electrode 231. When the penetration depth L1 of the needle 10 in the battery cell 20 is equal to C+S+D, the needle 10 penetrates the outermost second electrode 232 and the isolation membrane 233 on its lower surface in the process of movement, and then the needle tip contacts the upper surface of the first electrode 231; when the penetration depth L1 of the needle 10 in the battery cell 20 is equal to A+C+S+D, the needle 10 penetrates the outermost second electrode 232 and the isolation membrane 233 on its lower surface in the process of movement, and then continues to penetrate the first electrode 231, and then the needle tip reaches the lower surface of the first electrode 231. Therefore, when C+S+D≤L1≤A+C+S+D, the needle tip can be located at any position inside the first pole piece 231. At this time, the second pole piece 232 and the first pole piece 231 will be short-circuited by the needle 10, causing an internal short circuit in the battery cell 20, thereby achieving the purpose of the needle penetration test.

[0085] It is understandable that in actual applications, due to the sensitivity of the voltage detection device or the movement speed of the needle 10, the starting insertion position determined based on the above method may have deviations. For example, when the starting insertion position is determined based on the voltage between the positive electrode terminal and the needle 10, the needle 10 may have penetrated a certain depth into the outermost second electrode sheet 232. In this way, after the needle 10 continues to penetrate the predetermined depth, the actual penetration depth of the needle in the battery cell 10 is slightly greater than the predetermined depth. For example, if it is necessary to penetrate one electrode sheet, the maximum penetration depth L of the needle 10 in the battery cell 20 is 1max It may be slightly larger than A+C+S+D; if it is necessary to penetrate two layers of electrode sheets, the maximum penetration depth of the needle 10 in the battery cell 20 is L 2ma x may be slightly greater than (A+C+S+D)+(A+C+2S); ...; if it is necessary to penetrate N layers of electrode sheets, the maximum penetration depth of the needle 10 in the battery cell 20 is L Nmax It may be slightly larger than (A+C+S+D)+(A+C+2S)*(N-1).

[0086] Of course, as long as the deviation of the predetermined depth is within an acceptable range, such deviation can be accepted. Usually, the deviation of the predetermined depth will not exceed the preset value P. For example, when the number of layers of the electrode to be penetrated is 1, the maximum value L of the predetermined depth is 1max Satisfy A+C+S+D≤L 1max ≤A+C+S+D+P; when the number of layers of the electrode to be penetrated is N, the maximum value of the predetermined depth L 2max Satisfies (A+C+S+D)+(A+C+2S)*(N-1)≤L nmax ≤(A+C+S+D)+(A+C+2S)*(N-1)+P, where P is a preset value. For example, P may be equal to the thickness of the second pole piece 232 or the sum of the thickness of the second pole piece 232 and the thickness of the isolation film 233 .

[0087] As an example, generally, for a battery cell 10 of the NCM chemical system, the thicknesses of the positive electrode sheet, the negative electrode sheet and the separator (including CCS+PCS) are 0.116 mm, 0.173 mm and 0.011 mm respectively; for a battery cell 20 of the LFP chemical system, the thicknesses of the positive electrode sheet, the negative electrode sheet and the separator (including CCS+PCS) are 0.144 mm, 0.172 mm and 0.0118 mm respectively; for a sodium-ion battery cell 20, the thicknesses of the positive electrode sheet, the negative electrode sheet and the separator (including CCS+PCS) are 0.204 mm, 0.205 mm and 0.0120 mm respectively.

[0088] The thickness of the positive or negative electrode sheet of the battery cell 20 can be, for example, between 0.1 mm and 0.5 mm, or further, between 0.1 mm and 0.25 mm. The thickness of the negative electrode sheet can be greater than that of the positive electrode sheet. The thickness of the separator is typically much smaller than that of the positive and negative electrode sheets. Therefore, in the embodiments of the present application, the separator can be ignored when converting the number of layers and depth.

[0089] Optionally, the battery cell 20 further includes a housing (not shown in FIG. 4 ) configured to accommodate the laminated structure formed by the first electrode piece 231 and the second electrode piece 232 shown in FIG. A clearance hole is provided on the housing at a location for the needle 10 to penetrate. The clearance hole effectively avoids the needle 10, facilitating penetration of the electrode piece by the needle 10. The clearance hole can be slightly larger than the diameter of the needle 10, for example, the diameter of the clearance hole can be approximately 10 mm, e.g., greater than or equal to 10 mm.

[0090] In some embodiments, before performing the aforementioned penetration test, the battery cells 20 may be charged to a predetermined state of charge (SOC) and left to rest for a predetermined period of time. For example, the battery cells 20 may be charged to a cutoff voltage of the battery cells 20 at a predetermined current and left to rest for a predetermined period of time. By fully charging the battery cells 20 and then leaving them to rest, the battery cells 20 to be tested are in a stable state, thereby improving their penetration test performance.

[0091] In theory, the above-mentioned preset voltage can be any voltage value between 0V and the open circuit voltage of the battery cell 20. That is, as long as the voltage is detected to change from 0, the starting insertion position can be confirmed. When the sensitivity of the voltage detection device is sufficient, the smaller the preset voltage, the better. However, in actual applications, the preset voltage can be set to be greater than or equal to 0.5V and less than or equal to 1.5V, greater than or equal to 0.6V and less than or equal to 1.4V, greater than or equal to 0.7V and less than or equal to 1.3V, greater than or equal to 0.8V and less than or equal to 1.2V, or greater than or equal to 0.9V and less than or equal to 1.1V.

[0092] In the embodiment of the present application, the preset voltage is 1V. During the process of the needle 10 moving toward the battery cell 20, if the voltage between the needle 10 and the first electrode terminal suddenly exceeds the preset voltage, it is considered that the needle 10 touches or punctures the outermost second electrode sheet 232. The position of the needle 10 at this time can be used as the starting insertion position. Based on the starting insertion position, the needle 10 can be controlled to continue moving a certain distance and then stop. The distance that the needle 10 continues to move from the starting insertion position is equal to the predetermined depth.

[0093] If the preset voltage is large, the test accuracy will be relatively poor, and it will not be possible to locate the starting insertion position in time when the needle 10 touches or punctures the outermost second electrode 232; if the preset voltage is small, it places higher demands on the sensitivity of the test device, and the test results are easily affected by interference from other factors in the test. To this end, after repeated experimental demonstrations, it was found that when the preset voltage is within the above-mentioned voltage range, the deviation of the starting insertion position is within 1 layer, which can meet the test requirements of most battery cells. Preferably, the preset voltage can be set to 1V. Of course, if the sensitivity of the test device is high enough, the preset voltage can also be set to a smaller value, such as 0.5V, 0.6V, 0.7V or 0.8V, etc.

[0094] Figure 5 illustrates the changes in the interface between the electrode sheet and the needle 10 as the needle 10 penetrates the interior of a battery cell 20. Since a battery cell 20 is formed by the overlapping positive electrode sheet 1, separator, and negative electrode sheet, assuming the outermost electrode sheet is the negative electrode sheet, a voltage line is placed between the needle 10 and the positive electrode terminal of the battery cell 20, and the voltage V between the needle 10 and the positive electrode terminal is measured. As the needle 10 moves toward the battery cell 20, when it touches or punctures the outermost negative electrode sheet, the voltage V between the needle 10 and the positive electrode terminal suddenly increases to V1. Theoretically, V1 is approximately equal to the voltage between the positive and negative electrode terminals of the battery cell 20. However, during the actual test process, there are differences in the interface of the needle 10. As shown in Figure 5, due to the different contact methods between the needle 10 and the negative electrode plate, the corresponding contact resistance will change. After actual testing, the resistance can fluctuate to the maximum MΩ level. After the resistance is divided, it will cause the voltage V between the needle 10 and the positive electrode terminal to fluctuate.

[0095] For example, FIG6 shows a schematic diagram of an equivalent circuit between the needle 10 and the positive electrode terminal, where FIG6(a) is a schematic diagram of the connection between the needle 10 and the positive electrode terminal of the battery cell 20 during the needle penetration test, and FIG6(b) is the equivalent circuit of (a). As shown in FIG6(b), the contact resistance between the needle 10 and the negative electrode plate is R1, and R1 will divide the voltage, causing the voltage V between the needle 10 and the positive electrode terminal to fluctuate. FIG6(c) shows an equivalent circuit diagram after converting the voltage V between the needle 10 and the positive electrode terminal shown in FIG6(b) into a current and the corresponding resistance R2.

[0096] Using the above-mentioned method for determining the starting point of penetration, actual tests were conducted on different types of battery cells, yielding the test results shown in Table 1. The "sudden voltage" in Table 1 refers to the voltage V between the needle 10 and the positive electrode terminal when the needle 10 touches or punctures the outermost negative electrode during movement. Table 1 shows battery cells 20 with capacities of 151Ah, 160Ah, 138Ah, and 173Ah, as well as battery cells 20 using lithium iron phosphate (LiFePO4, LFP) and nickel-cobalt-manganese (Ni-Co-Mn, NCM) ternary materials, using the above-mentioned needle penetration test method 100.

[0097] Taking a preset voltage of 1V as an example, the position of the needle 10 when the voltage V between the needle 10 and the positive electrode terminal exceeds 1V during its movement can be considered the starting insertion position of the needle 10, i.e., the moment when the needle 10 touches or punctures the negative electrode tab. At this point, the battery cell 20 can be disassembled to determine the accuracy of the starting insertion position determined based on the sudden voltage change based on the state of each tab layer after disassembly. If accurate, the number of tab layers penetrated by the needle 10 after disassembly should be less than 1, i.e., equal to 0 or 0.5. Here, one positive tab layer and one negative tab layer are collectively referred to as one tab layer. Therefore, the 0.5 tab layer in Table 1 includes only one negative tab layer, i.e., only the negative tab layer is punctured by the needle 10; whereas the 0 tab layer in Table 1 indicates that the needle 10 touches but does not puncture the negative tab layer. It can be understood that no matter whether the needle 10 touches the negative electrode plate or punctures the negative electrode plate, the voltage V between the needle 10 and the positive electrode terminal will suddenly change, and the sudden change voltage is greater than or equal to the preset voltage 1V.

[0098] As can be seen from Table 1, based on the method 100 of the needle penetration test in the embodiment of the present application, for different types of battery cells 20, when the preset voltage is set to 1V, the deviation of the starting penetration position is less than 1 layer, and the starting penetration position can be accurately determined, thereby meeting the different test requirements of the needle penetration test.

[0099] Table 1

[0100] It should be understood that the above examples all use the outermost electrode sheet of the battery cell 20 as the negative electrode sheet, and connect the needle to the positive electrode terminal. If the outermost electrode sheet of the battery cell 20 is the positive electrode sheet, it is necessary to connect the needle to the negative electrode terminal. The specific testing process is similar and will not be repeated here for the sake of brevity.

[0101] FIG7 and FIG8 illustrate a possible specific implementation of the method 100 of the needle penetration test.

[0102] It is understood that before the needle penetration test, the battery cell 20 to be tested may be pre-treated, the SOC may be adjusted, and other operations may be performed.

[0103] Pre-processing includes taking photos of the battery cells to be tested, testing their voltage, internal resistance, and weight, and recording the state of the battery cells 20 before testing. Adjusting the SOC can be accomplished, for example, by charging the battery cells 20 to their cutoff voltage at a current of no less than 1 / 3C and then allowing them to rest for one to two hours to stabilize them. For hard-shell battery cells 20, peeling is also required to remove the shell of the test section. Peeling involves reserving a clearance hole of a certain diameter, such as at least 20 mm or at least 10 mm, in the shell of the battery cells 20 for the needle to penetrate.

[0104] As an example, as shown in FIG8 , the battery cell 20 may be fixed by a clamp 51 , and a clearance hole with a certain diameter, for example, at least 20 mm or at least 10 mm, is reserved on the clamp 51 for the position where the needle is inserted.

[0105] Alternatively, a high-temperature resistant steel needle with an insulating stopper 52 can be used as the needle 10. The diameter of the needle 10 can be, for example, 1 mm, and the cone angle of the needle tip can be, for example, 20° to 30°. The surface of the needle 10 should be smooth and free of rust, oxide layers, and oil stains. The needle 10 should move at a speed of, for example, less than or equal to 0.1 mm / s and penetrate the battery cell 20 in a direction perpendicular to the plate, with the penetration position close to the geometric center of the surface being penetrated.

[0106] The values ​​of parameters such as the diameter and moving speed of the needle 10 can be selected according to actual conditions, and the present application is not limited thereto.

[0107] Connect the positive electrode terminal of the battery cell 20 to the needle 10 via a voltage line and set the parameters. Figures 7 and 8 use the outermost second electrode 232 as the negative electrode as an example. Before testing, the battery cell to be tested can be charged to a predetermined SOC according to the charging method specified in the relevant standard. For example, to make the test conditions more stringent, the battery cell 20 is usually charged to 100% SOC.

[0108] As shown in FIG8 , in step 101 , the parameters of the acupuncture test are set, such as setting the above-mentioned preset voltage, predetermined depth and other parameters.

[0109] In step 102 , it is determined that a needle stick test is started.

[0110] In step 103 , the needle 10 is controlled to move, and the voltage between the needle 10 and the positive electrode terminal of the battery cell 20 is detected during the movement.

[0111] In step 104 , it is determined whether the voltage between the needle 10 and the positive electrode terminal exceeds a predetermined voltage during the movement of the needle 10 .

[0112] If the voltage exceeds the predetermined voltage, step 105 is executed.

[0113] In step 105, the position of the needle 10 when the voltage between the needle 10 and the positive electrode terminal exceeds the predetermined voltage is determined as the starting insertion position of the needle 10, and the needle is controlled to continue moving with the starting insertion position as the starting point.

[0114] For example, the position of the needle 10 when the voltage between the needle 10 and the positive electrode terminal exceeds the predetermined voltage is determined as the starting insertion position of the needle 10, and the needle 10 is controlled to continue moving with the starting insertion position as the starting point.

[0115] In step 106, it is determined whether the needle 10 has moved to a predetermined depth from the initial insertion position.

[0116] If the predetermined depth is reached, step 107 is executed. The predetermined depth is, for example, a penetration depth converted from a desired number of penetration layers, or a desired penetration depth such as 2 mm ± 0.5 mm.

[0117] In step 107 , the needle 10 is controlled to stop.

[0118] Afterwards, the state of the battery cell 20 can be observed. For example, the battery cell 20 can be observed for a certain period of time, such as one hour, at the test ambient temperature to see if fire, explosion, or the like occurs in the battery cell 20.

[0119] In step 108 , it is determined that the needle prick test is complete.

[0120] The needle 10 is removed, and the battery cell 20 is discharged to a specified discharge termination voltage. The battery cell 20 is disassembled and the number of short-circuit layers is recorded.

[0121] As can be seen, based on the above-described needle penetration test process, the starting penetration position of the needle 10 when it touches or penetrates the outermost second electrode sheet 232 can be accurately determined, and the needle 10 can be controlled to continue moving based on the starting penetration position until it penetrates the battery cell 20 to a predetermined depth. In this way, without the need for complex modifications to the battery cell 20, the needle penetration test can be completed accurately and conveniently by utilizing the relationship between the physical structure and voltage of the battery cell 20, improving test accuracy while also meeting testing requirements for different penetration depths.

[0122] The present application also provides a device 200 for acupuncture testing. As shown in FIG9 , the device 200 includes a processing module 40 and a detection module 30 .

[0123] The processing module 40 is configured to control the needle 10 to move toward the battery cell 20. The detection module 30 is configured to detect the voltage between the needle 10 and the first electrode terminal of the battery cell 20 during the movement of the needle 10. The processing module 40 is further configured to continue controlling the needle 10 to penetrate the battery cell 20 to a predetermined depth if the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds a preset voltage.

[0124] The preset voltage is, for example, between 0.5V and 1.5V, such as 1V.

[0125] In some embodiments, the battery cell 20 includes a first electrode piece 231 and a second electrode piece 232 that are overlapped, and the electrode piece located on the outermost layer is the second electrode piece 232. The first electrode terminal is an electrode terminal connected to the first electrode piece 231, and the polarity of the first electrode piece 231 and the second electrode piece 232 are opposite.

[0126] In some embodiments, the predetermined depth is determined based on the number of layers of the electrode that need to be penetrated in the needle penetration test.

[0127] In some embodiments, the predetermined depth is determined based on the number of electrode layers to be penetrated, the thickness of the first electrode 231 , and the thickness of the second electrode 232 .

[0128] In some embodiments, the predetermined depth is determined based on the number of layers, the thickness of the first pole piece 231 , the thickness of the second pole piece 232 , and the thickness of the isolation membrane 233 between the first pole piece 231 and the second pole piece 232 and / or a preset gap value.

[0129] In some embodiments, when the number of layers is 1, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D; and / or, when the number of layers is N, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), where N is a positive integer greater than 1. A, C, S, and D are the thickness of the first pole piece 231 , the thickness of the second pole piece 232 , the thickness of the isolation film 233 , and the gap value, respectively.

[0130] In some embodiments, the processing module 40 is further configured to control the battery cells 20 to be charged to a predetermined SOC.

[0131] It should be understood that the device 200 is used to perform the above-mentioned method 100 of the acupuncture test. The specific details of the device 200 can be referred to the above description of the method 100. For the sake of brevity, they are not repeated here.

[0132] This application also provides a device for performing a needle prick test. As shown in FIG10 , the device 300 includes a processor 310 configured to execute computer instructions stored in a memory 320, thereby enabling the device to implement the needle prick test method 100 described in any of the aforementioned embodiments. The device 300 may, for example, be a host computer. Optionally, the device 300 also includes a memory 320 configured to store computer instructions. The memory 320 may be a separate device independent of the processor 310, or it may be integrated into the processor 310.

[0133] Optionally, as shown in FIG10 , the detection device 300 may further include a transceiver 330 , and the processor 310 may control the transceiver 330 to communicate with other devices, for example, to send information or data to other devices, or to receive information or data sent by other devices.

[0134] It should be understood that the processor in the embodiments of the present application may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above-mentioned method embodiment may be completed by hardware integrated logic circuits in the processor or by software instructions. The above-mentioned processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of the present application may be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above-mentioned method.

[0135] It is understood that the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DR RAM). It should be noted that the memory of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0136] The present application also provides a computer-readable storage medium for storing a computer program, which, when executed by a computing device, enables the computing device to implement the acupuncture test method 100 described in any of the above embodiments. The computer-readable storage medium may be, for example, the memory 320 .

[0137] It should be noted that, under the premise of no conflict, the various embodiments and / or technical features in each embodiment described in this application can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the scope of protection of this application.

[0138] In the embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0139] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0140] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems, devices and units can refer to the corresponding processes in the above-described method embodiments and will not be repeated here.

[0141] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0142] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solutions of the embodiments of the present application.

Claims

1. A method for acupuncture testing, characterized in that: The method comprises: Controlling the needle to move in a direction of piercing the battery cell; When the voltage between the puncture needle and the first electrode terminal of the battery cell exceeds a preset voltage, the puncture needle is continuously controlled to puncture to a predetermined depth.

2. The method according to claim 1, characterized in that The battery cell includes a first pole piece and a second pole piece that are overlapped, and the pole piece located at the outermost layer is the second pole piece. The first electrode terminal is an electrode terminal connected to the first pole piece, and the polarities of the first pole piece and the second pole piece are opposite.

3. The method according to claim 1 or 2, characterized in that: The predetermined depth is determined according to the number of layers of the electrode sheet that need to be pierced in the needle penetration test.

4. The method according to claim 3, characterized in that The predetermined depth is determined according to the number of layers, the thickness of the first pole piece of the battery cell, and the thickness of the second pole piece of the battery cell.

5. The method according to claim 4, characterized in that The predetermined depth is determined according to the number of layers, the thickness of the first pole piece, the thickness of the second pole piece, the thickness of the isolation film between the first pole piece and the second pole piece, and / or a preset gap value.

6. The method according to claim 5, characterized in that When the number of layers is 1, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D; and / or, When the number of layers is N, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), N is a positive integer greater than 1; Wherein, A is the thickness of the first pole piece, C is the thickness of the second pole piece, S is the thickness of the isolation film, and D is the gap value.

7. The method according to any one of claims 1 to 6, characterized in that The preset voltage is greater than or equal to 0.5V and less than or equal to 1.5V.

8. The method according to claim 7, characterized in that The preset voltage is 1V.

9. The method according to any one of claims 1 to 8, characterized in that The battery cell further comprises a shell, wherein the shell is used to accommodate the first pole piece and the second pole piece of the battery cell, and an avoidance hole is arranged at a position for the puncture needle to pierce.

10. The method according to any one of claims 1 to 9, characterized in that The method further comprises: The battery cells are controlled to be charged to a predetermined state of charge (SOC) and left to stand for a predetermined period of time.

11. A device for acupuncture testing, characterized in that: The device comprises: A processing module, used for controlling the needle to move in a direction of piercing the battery cell; A detection module, used for detecting the voltage between the pricking needle and the first electrode terminal of the battery cell during the movement of the pricking needle; The processing module is also used for continuing to control the puncture needle to penetrate to a predetermined depth when the voltage between the puncture needle and the first electrode terminal of the battery cell exceeds a preset voltage.

12. The device according to claim 11, characterized in that The battery cell includes a first pole piece and a second pole piece that are overlapped, and the pole piece located at the outermost layer is the second pole piece. The first electrode terminal is an electrode terminal connected to the first pole piece, and the polarities of the first pole piece and the second pole piece are opposite.

13. The device according to claim 11 or 12, characterized in that The predetermined depth is determined according to the number of layers of the electrode sheet that need to be pierced in the needle penetration test.

14. The device according to claim 13, characterized in that The predetermined depth is based on the number of layers, the thickness of the first pole piece of the battery cell, and the thickness of the second pole piece of the battery cell.

15. The device according to claim 14, characterized in that The predetermined depth is determined according to the number of layers, the thickness of the first pole piece, the thickness of the second pole piece, the thickness of the isolation film between the first pole piece and the second pole piece, and / or a preset gap value.

16. The device according to claim 15, characterized in that When the number of layers is 1, the predetermined depth is L1, C+S+D≤L1≤A+C+S+D; and / or, When the number of layers is N, the predetermined depth is L N , (A+C+S+D)+(A+C+2S)*(N-2)+(C+2S)≤L N ≤(A+C+S+D)+(A+C+2S)*(N-1), N is a positive integer greater than 1; Wherein, A, C, S and D are respectively the thickness of the first pole piece, the thickness of the second pole piece, the thickness of the isolation film, and the gap value.

17. The device according to any one of claims 11 to 16, characterized in that The preset voltage is greater than or equal to 0.5V and less than or equal to 1.5V.

18. The device according to claim 17, characterized in that The preset voltage is 1V.

19. The device according to any one of claims 11 to 18, characterized in that The battery cell further comprises a shell, wherein the shell is used to accommodate the first pole piece and the second pole piece of the battery cell, and an avoidance hole is arranged at a position for the puncture needle to pierce.

20. The device according to any one of claims 11 to 19, characterized in that The processing module is further used to control the battery cells to be charged to a predetermined state of charge SOC.

21. A device for a needle puncture test, characterized in that: The device comprises a processor, wherein the processor is used to execute computer instructions stored in the memory so as to enable the device to implement the method of acupuncture test according to any one of claims 1 to 10.

22. A computer-readable storage medium, characterized in that: Used to store a computer program, which, when executed by a computing device, causes the computing device to implement the method for the needle penetration test according to any one of claims 1 to 10.

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