Acupuncture test method and device

Abstract

The invention relates to an acupuncture test method and device, which can improve the acupuncture test performance. The method comprises the following steps: controlling a pricking needle to move towards the direction of pricking into a single battery; and under the condition that the voltage between the pricking needle and the first electrode terminal of the battery monomer exceeds the preset voltage, continuously controlling the pricking needle to prick into the preset depth.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a method and device for a needle penetration test. Background Art

[0002] The battery puncture test is also called the internal short circuit test, which is used to evaluate the safety risk of the battery cell when an internal short circuit occurs. Usually, a puncture needle is used to pierce the battery cell to evaluate the safety risk caused by the short circuit between the electrode in the battery cell and the puncture needle. How to improve the performance of the puncture test has become an urgent problem to be solved. Summary of the invention

[0003] 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.

[0004] 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.

[0005] Optionally, 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 polarity of the first pole piece is opposite to that of the second pole piece.

[0006] When the needle moves toward the battery cell, the voltage between the first electrode terminal connected to the first pole piece is detected. This voltage will change significantly when the needle touches or pierces the second pole piece located at the outermost layer. Therefore, in the embodiment of the present application, the position of the needle at the moment when the voltage exceeds the preset voltage is used as the starting piercing position of the needle on the battery cell, that is, the position when the needle touches or pierces the second pole piece at the outermost layer, and the starting piercing position is used as the starting point to control the needle to continue to move to a predetermined depth inside the battery cell. In this way, there is no need to carry out complex modifications to the battery cell. By utilizing the relationship between the physical structure and voltage of the battery cell, the needle puncture test can be completed accurately and conveniently, which can improve the test accuracy and meet different test requirements.

[0007] In a possible implementation, the predetermined depth is determined according to the number of electrode layers that need to be pierced in the needle penetration test.

[0008] In practical applications, the need for needle penetration testing is usually characterized by the number of layers, that is, how many layers of electrode sheets need to be penetrated. By converting the number of layers of electrode sheets that need to be penetrated into the penetration depth, the desired test requirements can be achieved through the above-mentioned needle penetration test method.

[0009] 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.

[0010] 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 piece. For example, the predetermined depth is determined according to the number of layers, the thickness of the first electrode piece, and the thickness of the second electrode piece.

[0011] 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 film between the first pole piece and the second pole piece and / or a preset gap value.

[0012] Since the thickness of the isolation film between the first pole piece and the second pole piece is taken into consideration, or a preset gap value is set, the accuracy of the conversion between the number of layers and the depth can be improved. Among them, the stacking of the first pole piece and the second pole piece has a certain degree of looseness, and when the needle penetrates the battery cell, it will press the pole piece in the penetration area. Through the gap value, a certain compensation can be made, thereby improving the test accuracy.

[0013] For example, when the number of layers is 1, the predetermined depth is L 1 , C+S+D≤L 1 ≤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.

[0014] 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 demonstrations, when the preset voltage is in 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 test requirements of most battery cells.

[0015] In a possible implementation, the battery cell further includes a housing for accommodating the first pole piece and the second pole piece, and a clearance hole is provided on the housing at a position for the puncture needle to penetrate. The clearance hole can effectively avoid the puncture needle to facilitate the puncture needle to penetrate the pole piece.

[0016] In a possible implementation, the method further includes: controlling the battery cell to be charged to a predetermined SOC and to stand for a predetermined time. The battery cell is charged to a predetermined SOC and is left to stand so that the battery cell to be tested is in a stable state, thereby improving its performance in the needle penetration test.

[0017] In a second aspect, a device for a needle penetration test is provided, the device comprising: a processing module for controlling the movement of a needle toward a direction of penetrating a battery cell; a detection module for detecting the voltage between the needle and a 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.

[0018] Optionally, 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 polarity of the first pole piece is opposite to that of the second pole piece.

[0019] In a possible implementation, the predetermined depth is determined according to the number of electrode layers that need to be pierced in the needle penetration test.

[0020] 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.

[0021] 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 film between the first pole piece and the second pole piece and / or a preset gap value.

[0022] In a possible implementation, when the number of layers is 1, the predetermined depth is L 1 , C+S+D≤L 1 ≤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 membrane, and the gap value.

[0023] 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.

[0024] In a possible implementation, the battery cell further includes a shell, the shell is used to accommodate the first pole piece and the second pole piece, and a avoidance hole is provided on the shell at a position for the puncture needle to pierce.

[0025] In a possible implementation, the processing module is further used to control the battery cells to be charged to a predetermined SOC.

[0026] In a third aspect, a device for acupuncture testing is provided, comprising a processor, wherein the processor is used to execute computer instructions stored in a memory so that the device implements the method for acupuncture testing described in the first aspect or any possible implementation of the first aspect.

[0027] In a fourth aspect, a computer-readable storage medium is provided for storing a computer program, and when the computer program is executed by a computing device, the computing device implements the method of acupuncture testing described in the first aspect or any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. 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 paying creative work.

[0029] Figure 1 is a schematic diagram of the acupuncture test.

[0030] Figure 2 is a schematic diagram of the starting insertion position for the acupuncture test.

[0031] Figure 3 Schematic flow chart of the method for acupuncture test according to an embodiment of the present application.

[0032] Figure 4 It is a schematic diagram of a possible electrode stack of a battery cell according to an embodiment of the present application.

[0033] Figure 5 It is a schematic diagram of the changes in the interface between the electrode and the needle during the insertion of the needle.

[0034] Figure 6 is a schematic diagram of the equivalent circuit between the puncture needle and the positive electrode terminal.

[0035] Figure 7 yes Figure 3 A schematic diagram of a possible specific implementation of the acupuncture test method is shown.

[0036] Figure 8 yes Figure 3 The schematic flow chart of a possible specific implementation of the acupuncture test method is shown.

[0037] Fig. 9 It is a schematic block diagram of a device for acupuncture test according to an embodiment of the present application.

[0038] Fig.10 It is a schematic block diagram of a device for acupuncture test according to an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following detailed description and drawings of the embodiments of the present application are used to illustrate the principles of the present application, but cannot be used to limit the scope of the present application, that is, the present application is not limited to the described embodiments.

[0040] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those generally 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 of this application or the above-mentioned figures are used to distinguish different objects, not to describe a specific order or a primary and secondary relationship. "Vertical" is not strictly perpendicular, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0041] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0042] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0043] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0044] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0045] A battery generally refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. For example, the battery may include a battery module or a battery pack. Typically, a battery also includes a box for encapsulating one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

[0046] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet, and a separator between the positive electrode sheet and the negative electrode sheet. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the main part of the positive electrode collector. The part of the positive electrode collector that is not coated with the positive electrode active material layer protrudes from the main part of the positive electrode collector as a positive electrode ear. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the main part of the negative electrode collector. The part of the negative electrode collector that is not coated with the negative electrode active material layer protrudes from the main part of the negative electrode collector as a negative electrode ear. The material of the negative electrode collector can be copper, and the negative electrode active material can be carbon or silicon. In order to reduce the probability of melting due to a large current, there can be multiple positive electrode tabs stacked together, and there can be multiple negative electrode tabs stacked together.

[0047] In order to simulate the internal short circuit scenario caused by the battery being contaminated by conductive particles, a needle with a diameter of about 1 mm can be used to pierce the pole piece in the battery cell to cause an internal short circuit in the battery cell, thereby evaluating the safety risk of the battery cell when an internal short circuit occurs. This process is usually called a needle puncture test, a shallow puncture test, or an internal short circuit test of the battery. It can be understood that the puncture position of the needle on the pole piece corresponds to the main part of the current collector coated with the active material layer on the pole piece.

[0048] For example, Figure 1 As shown, the needle 10 is connected to the first electrode terminal 21 of the battery cell 20, and the polarity of the first electrode terminal 21 and the second electrode terminal 22 are opposite, 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 in the outermost layer, the first electrode terminal 21 connected to the needle 10 is a negative electrode terminal; if the negative electrode sheet is in the outermost layer, the first electrode terminal 21 connected to the needle 10 is a positive electrode terminal.

[0049] Taking the case where the negative electrode sheet is at the outermost layer and the first electrode terminal 21 is the positive electrode terminal as an example, the needle 10 is connected to the first electrode terminal 21. In the process of the needle 10 moving toward the battery cell 20, before the needle 10 moves to touch or pierce the outermost negative electrode sheet, no circuit is formed between the outermost negative electrode sheet, the needle 10, the detection module 30, and the first electrode terminal 21. At the moment when the needle 10 moves to touch or pierce the outermost negative electrode sheet, a circuit is formed between the outermost negative electrode sheet, the needle 10, the detection module 30, and the first electrode terminal 21, and the detection module 30 can detect the voltage between the positive and negative electrode sheets. As the needle 10 continues to penetrate into the battery cell 20, an internal short circuit is formed between the positive electrode sheet and the negative electrode sheet through the needle 10, and the detection module 30 can detect that a voltage drop occurs 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 pierces the negative electrode sheet and the positive electrode sheet of the first layer of the battery cell 20.

[0050] Generally, the requirement of the needle penetration test is that the needle 10 penetrates a layer of positive electrode sheet and negative electrode sheet in the battery cell 20. The processing module 40 can determine whether the needle 10 penetrates a layer of positive electrode sheet and negative electrode sheet of the battery cell 20 according to the change of the voltage between the needle 10 and the first electrode terminal 21 detected by the detection module 30.

[0051] However, in other scenarios, it is also expected that the test needle 10 will penetrate multiple layers of positive and negative pole sheets in the battery cell 20. Due to the stacking arrangement between the positive and negative pole sheets, there is a certain degree of looseness, for example, Figure 2As shown, when the needle 10 penetrates the battery cell 20, the electrode sheet 23 is pressed 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, the voltage drop generated when the multi-layer positive electrode sheet and the negative electrode sheet are short-circuited by the needle 10 cannot be identified, and thus it cannot meet more test requirements.

[0052] To this end, the present application proposes a puncture test scheme, which aims to utilize the relationship between the physical structure and voltage of the battery cell to determine the starting penetration position of the puncture needle on the battery cell, and then control the penetration depth or number of layers of the puncture needle in the battery cell based on the starting penetration position, so as to meet different testing requirements.

[0053] As an example, Figure 3 A schematic flow chart of the method for the puncture test of an embodiment of the present application is shown. The battery cells to be tested may include, for example, secondary batteries such as sodium-ion batteries and lithium-ion batteries, and their structure 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, and the polarity of the first pole piece is opposite to that of the second pole piece. Method 100 can be applied to the puncture test of battery cells 20 of various structural types, and the battery cell 20 may be a winding structure, a stacked structure, a cylindrical battery cell, or a soft-pack battery cell. These battery cells can all be tested using the puncture test method 100 provided in the embodiment of the present application.

[0054] like Figure 3 As shown, method 100 includes some or all of the following steps.

[0055] In step 110 , the puncture needle 10 is controlled to move in a direction of puncturing the battery cell 20 .

[0056] In step 120 , when the voltage between the puncture needle 10 and the first electrode terminal of the battery cell 20 exceeds the preset voltage, the puncture needle 10 is continuously controlled to puncture to a predetermined depth.

[0057] Optionally, the battery cell 20 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 the electrode terminal on the battery cell 20 connected to the first pole piece, and the polarities of the first pole piece and the second pole piece are opposite.

[0058] 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.

[0059] The "when the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds the preset voltage" mentioned 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, in the process of the needle 10 moving toward the battery cell 20, it is necessary to detect the voltage between the needle 10 and the first electrode terminal of the battery cell 20, and use 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 as the starting insertion position of the needle 10 on the battery cell 20, so that based on the starting insertion position, the needle 10 is inserted into the battery cell 20 to the predetermined depth. The predetermined depth is the distance that the needle 10 moves inside the battery cell 20, that is, the depth to which the needle 10 penetrates the battery cell 20.

[0060] 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.

[0061] The initial insertion position refers to the position of the needle 10 when the needle 10 begins to penetrate the battery cell 20. At this time, the needle 10 may touch or slightly pierce the outermost second pole piece. That is to say, the initial insertion position can be regarded as the position of the needle 10 when the needle 10 touches or pierces the outermost second pole piece. For example, it can be the position of the needle tip of the needle 10, the position of the needle tail of the needle 10, or the position of other parts of the needle 10. Then, the initial insertion position can be used as a starting point to control the needle 10 to continue moving until it penetrates to a predetermined depth of the battery cell 20. Here, the step of controlling the needle 10 includes direct or indirect control of the needle 10, that is, directly controlling the needle 10 to penetrate the predetermined depth inside the battery cell 20 from the initial insertion position; or, by controlling a clamping device for clamping the needle 10, the needle 10 penetrates the predetermined depth inside the battery cell 20 from the initial insertion position.

[0062] The voltage between the needle 10 and the first electrode terminal is detected during the process of moving toward the battery cell 20. When the needle 10 touches or punctures the outermost second electrode sheet, a loop is formed between the outermost second electrode sheet, the needle 10, the detection module 30, and the first electrode terminal 21, and the voltage between the needle 10 and the first electrode terminal 21 changes. Therefore, the embodiment of the present application determines the moment when the voltage between the needle 10 and the first electrode terminal exceeds the preset voltage, and the position to which the needle 10 moves at this moment, as the starting puncture position. With the starting puncture position as the starting point, the needle 10 is controlled to continue to move to a predetermined depth inside the battery cell 20. In this way, there is no need to perform complex modifications on the battery cell 20. By utilizing the relationship between the physical structure and voltage of the battery cell 20, the starting puncture position at which the needle starts to puncture the battery cell 20 can be determined, so as to implement a puncture test on a predetermined number of layers or a predetermined depth in the battery cell 20, and meet the test requirements for different puncture layers and depths.

[0063] The direction of piercing the battery cell 20 in step 110 may be, for example, a direction perpendicular to or approximately perpendicular to the pole piece of the battery cell 20. In other words, the needle 10 may pierce the pole piece 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 or approximately perpendicular to the pole piece surface.

[0064] The need for the puncture test can be characterized by the number of layers. The need for the puncture test may be that the puncture needle 10 is expected to penetrate multiple layers of positive and negative pole pieces in the battery cell 20. Optionally, the predetermined depth in step 120 is associated with the number of layers of pole pieces that need to be penetrated in the puncture test. For example, different depths correspond to different numbers of layers. When the number of layers of the pole piece to be penetrated is N1, the predetermined depth is M1; when the number of layers of the pole piece to be penetrated is N2, the predetermined depth is M2; when the number of layers of the pole piece to be penetrated is N3, the predetermined depth is M3; and so on.

[0065] To this end, the number of layers of the electrode sheet to be penetrated needs to be converted into the penetration depth, so as to control the moving distance of the needle 10 based on the starting penetration position, so that it penetrates to a predetermined depth in the battery cell 20. In this way, the desired test requirements can be achieved through the above-mentioned needle penetration test method.

[0066] Of course, if the need for the needle penetration test is characterized by depth, for example, the need for the needle penetration test may be to expect the needle 10 to penetrate a predetermined depth into the battery cell 20. Then, after determining the initial penetration position, the needle 10 can be controlled to continue to move a corresponding distance based on the initial penetration position. For example, if the predetermined depth is 1.5 mm, then the needle 10 can be controlled to continue to move 1.5 mm with the initial penetration position as the starting point; for another example, if the predetermined depth is 2 mm, then the needle 10 can be controlled to continue to move 2 mm with the initial penetration position as the starting point.

[0067] Therefore, in some embodiments, method 100 further includes: determining the predetermined depth according to the number of layers of the electrode that needs to be penetrated in the needle penetration test. That is, the predetermined depth can be determined based on the number of layers of the electrode that needs to be penetrated in the needle penetration test. It can be understood that the number of layers of the electrode described in the embodiment of the present application refers to the number of layers of a pair of electrode formed by the first electrode and the second electrode, that is, each layer of electrode includes a first electrode and a second electrode. In the case of considering the isolation film, each layer of electrode may include a first electrode, a second electrode, and an isolation film or two isolation films.

[0068] The “penetration” described in the embodiments of the present application can be understood in a broad sense, and the puncture needle 10 piercing into a certain electrode piece includes the puncture needle 10 touching and / or puncturing the electrode piece.

[0069] Figure 4 A schematic diagram of a possible electrode stack of a battery cell 20 is shown. Figure 4As shown, the first pole piece 231 and the second pole piece 232 are overlapped, and the pole piece located at the outermost layer is the second pole piece 232. An isolation film 233 is arranged between the first pole piece 231 and the second pole piece 232, and an insulating layer 234 is also arranged at the outermost layer. When the needle 10 moves toward the battery cell 20, the needle 10 will first penetrate the outermost insulating layer 234 and the two layers of isolation films 233, and in this process, the pole pieces are compressed to a certain extent. After that, it will touch or penetrate the outermost second pole piece 232, and in this process, the voltage change between the first electrode terminal of the battery cell and the needle 10 is detected, so as to determine the starting insertion position according to the voltage change.

[0070] Based on the initial piercing position, the needle 10 continues to move and sequentially pierces the first layer of the electrode sheet, the second layer of the electrode sheet, the third layer of the electrode sheet, and so on. As an example, Figure 4 Only three layers of pole pieces are shown, wherein the first layer of pole pieces includes a first pole piece 231, a second pole piece 232 and an isolation film 233 therebetween. Starting from the second layer of pole pieces, each layer of pole pieces includes a first pole piece 231, a second pole piece 232 and two isolation films 233, for example Figure 4 The second and third pole pieces are shown.

[0071] It should be noted that the definition of the number of electrode layers in the embodiment 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. Figure 4 As shown, the first layer of pole pieces includes a second pole piece 232 , the second layer of pole pieces includes a first pole piece 231 and an isolation film 233 , the third layer of pole pieces includes a second pole piece 232 and an isolation film, and so on.

[0072] 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. Further, 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, and the thickness of the isolation film between the first pole piece and the second pole piece and / or a preset gap value.

[0073] 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 .

[0074] 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 a preset gap value D.

[0075] 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.

[0076] Optionally, when the number of electrode layers to be penetrated is 1, that is, it is desired to penetrate one layer of the first electrode 231 and one layer of the second electrode 232, the predetermined depth is L 1 , C+S+D≤L 1 ≤A+C+S+D, wherein A is the thickness of the first pole piece 231, C is the thickness of the second pole piece 232, S is the thickness of the isolation film 233, and D is the gap value.

[0077] Exemplarily, the above-mentioned depth range can be mapped according to data such as the first pole piece 231, the second pole piece 232, the isolation film 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.

[0078] Optionally, when the number of electrode sheets to be penetrated is N, that is, it is desired to penetrate N layers of first electrode sheets 231 and N layers of second electrode sheets 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.

[0079] Since the first pole piece 231 and the second pole piece 232 of the battery cell 20 have different compaction degrees after overlapping, there will be a certain gap between the pole pieces, and the size of the gap value D can be determined, for example, according to the process technology. When the puncture needle 10 punctures the battery cell 20, it will press the pole piece in the puncture area, and the gap value D can be used to compensate to a certain extent, thereby improving the test accuracy.

[0080] For example, if one electrode layer needs to be penetrated, the penetration depth L of the needle 10 in the battery cell 20 is 1 It can be in the range of C+S+D to A+C+S+D. If two layers of pole pieces need to be penetrated, the penetration depth L of the needle 10 in the battery cell 20 is 2 It can be in the range of (A+C+S+D)+(C+2S) to (A+C+S+D)+(A+C+2S); ...; If it is necessary to penetrate N layers of pole pieces, the penetration depth L of the needle 10 in the battery cell 20 is 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 pole piece 231 and the second pole piece 232 in each layer of pole pieces can be short-circuited to achieve an internal short circuit at the corresponding position in the battery cell 20.

[0081] Take the case where one electrode layer, i.e. the first electrode layer, needs to be penetrated as an example. Figure 4 As shown, the first layer of sheets includes the second electrode sheet 232, the isolation film 233 and the first electrode sheet 231 from top to bottom. 1 = C + S + D, the needle 10 sequentially penetrates the outermost second electrode 232 and the isolation film 233 on the lower surface thereof during the movement, and then the needle tip contacts the upper surface of the first electrode 231; when the penetration depth L of the needle 10 in the battery cell 20 1 =A+C+S+D, the needle 10 successively penetrates the outermost second electrode 232 and the isolation film 233 on its lower surface during the movement, and then penetrates the first electrode 231 until the needle tip reaches the lower surface of the first electrode 231. 1 ≤A+C+S+D, the needle tip can be located at any position in 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 puncture needle 10, causing an internal short circuit in the battery cell 20, thereby achieving the purpose of the puncture test.

[0082] It is understandable that in actual applications, due to the sensitivity of the voltage detection device or the moving speed of the needle 10, etc., 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 one electrode sheet needs to be penetrated, the maximum penetration depth L of the needle 10 in the battery cell 20 is 1max It may be slightly greater than A+C+S+D; if two layers of pole pieces need to be penetrated, the maximum penetration depth of the needle 10 in the battery cell 20 is L 2max It may be slightly greater than (A+C+S+D)+(A+C+2S); ...; If it is necessary to penetrate N layers of pole pieces, 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).

[0083] Of course, as long as the deviation of the predetermined depth is within an acceptable range, such deviation is acceptable. 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 is L 2max Satisfies (A+C+S+D)+(A+C+2S)*(N-1)≤L nmax ≤(A+C+S+D)+(A+C+2S)*(N-1)+P. Wherein, 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 .

[0084] As an example, generally, for a battery cell 10 of an 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 an 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.

[0085] The thickness of the positive electrode sheet or the negative electrode sheet of the battery cell 20 may be, for example, between 0.1 mm and 0.5 mm, and further, between 0.1 mm and 0.25 mm, wherein the thickness of the negative electrode sheet may be greater than the thickness of the positive electrode sheet. The thickness of the separator is usually much smaller than the thickness of the positive electrode sheet and the negative electrode sheet, therefore, in the embodiment of the present application, the separator may also be ignored when converting the number of layers and the depth.

[0086] Optionally, the battery cell 20 further includes a housing ( Figure 4 Not shown), the housing is used to accommodate Figure 4 The first pole piece 231 and the second pole piece 232 are shown to form a laminated structure, and a avoidance hole is provided on the housing at a position for the needle 10 to penetrate. The avoidance hole can effectively avoid the needle 10, so as to facilitate the needle 10 to penetrate the pole piece. The size of the avoidance hole can be slightly larger than the diameter of the needle 10, for example, the diameter of the avoidance hole can be set to be about 10 mm, for example, greater than or equal to 10 mm.

[0087] In some embodiments, before the above-mentioned needle penetration test is performed, the battery cell 20 may be charged to a predetermined state of charge (SOC) and left to stand for a predetermined period of time. For example, based on a predetermined current, the battery cell 20 is charged to a cut-off voltage of the battery cell 20 and left to stand for a predetermined period of time. By charging the battery cell 20 to a fully charged state and leaving it to stand, the battery cell 20 to be tested is in a stable state, which can improve the performance of its needle penetration test.

[0088] Theoretically, 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 preset voltage is as small as possible. However, in practical 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.

[0089] In the embodiment of the present application, the preset voltage is 1V as an example. In 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 changes to exceed the preset voltage, it is considered that the needle 10 touches or punctures the outermost second electrode sheet 232, and the position of the needle 10 at this time can be used as the starting insertion position, and based on the starting insertion position, the needle 10 is controlled to continue to move a certain distance and then stop, and the distance that the needle 10 continues to move from the starting insertion position is equal to the above-mentioned predetermined depth.

[0090] If the preset voltage is large, the test accuracy will be relatively poor, and the starting insertion position cannot be located in time when the needle 10 touches or punctures the outermost second pole piece 232; if the preset voltage is small, it brings higher requirements on the sensitivity of the test device, and the test results are easily affected by the interference caused by other factors in the test. For this reason, 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, when 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.

[0091] Figure 5The figure shows the changes in the interface between the electrode sheet and the needle 10 during the process of the needle 10 piercing into the interior of the battery cell 20. Since the battery cell 20 is formed by the overlapping of the positive electrode sheet 1, the isolation membrane and the negative electrode sheet, assuming that the outermost electrode sheet is the negative electrode sheet, a voltage line is arranged 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 detected. In the process of the needle 10 moving toward the battery cell 20, when the needle 10 touches or pierces the outermost negative electrode sheet, the voltage V between the needle 10 and the positive electrode terminal will suddenly increase to V1. In theory, V1 is approximately equal to the voltage between the positive electrode terminal and the negative electrode terminal of the battery cell 20. However, in the actual test process, there are differences in the interface of the needle 10, such as Figure 5 As shown, due to the different contact modes between the needle 10 and the negative electrode plate, the corresponding contact resistance value will change. After actual detection, the resistance value can fluctuate to the MΩ level at most. After voltage division, the voltage V between the needle 10 and the positive electrode terminal will fluctuate.

[0092] For example, Figure 6 The schematic diagram of the equivalent circuit between the needle 10 and the positive electrode terminal is shown, wherein Figure 6 (a) is a schematic diagram of the connection between the puncture needle 10 and the positive electrode terminal of the battery cell 20 in the puncture test. Figure 6 (b) in the figure is the equivalent circuit of (a), as Figure 6 As shown in (b) in FIG. 1 , the contact resistance between the needle 10 and the negative electrode plate is R1, and R1 divides the voltage, causing the voltage V between the needle 10 and the positive electrode terminal to fluctuate. Figure 6 (c) shows that Figure 6 FIG. 1 is an equivalent circuit diagram showing the voltage V between the needle 10 and the positive electrode terminal converted into a current and the corresponding resistance R2.

[0093] By using the above method to determine the starting insertion position, different types of battery cells are actually tested, and the test results shown in Table 1 can be obtained. 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 plate during movement. Table 1 is for battery cells 20 with capacities of 151Ah, 160Ah, 138Ah and 173Ah, and the chemical system is lithium iron phosphate (LiFePO 4 The battery cell 20 made of LFP (LFP) material and nickel-cobalt-manganese (Ni-Co-Mn, NCM) ternary material is tested using the above-mentioned needle penetration test method 100.

[0094] Taking the 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 the movement of the needle 10 can be considered as the starting insertion position of the needle 10, that is, the moment when the needle 10 touches or punctures the negative electrode sheet. At this time, the battery cell 20 can be disassembled to determine whether the starting insertion position determined based on the sudden voltage is accurate according to the state of each layer of the electrode sheet after disassembly. If accurate, the number of layers pierced by the needle 10 after disassembly should be less than 1 layer, that is, the number of pierced layers is equal to 0 layers or 0.5 layers. Here, 1 layer of positive electrode sheet and 1 layer of negative electrode sheet are collectively referred to as 1 layer of electrode sheet. Therefore, 0.5 layers in Table 1 only include 1 layer of negative electrode sheet, that is, only the negative electrode sheet is punctured by the needle 10; and 0 layers in Table 1 indicate that the needle 10 touches the negative electrode sheet but has not punctured the negative electrode sheet. 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.

[0095] 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.

[0096] Table 1

[0097]

[0098]

[0099] It should be understood that the above examples are all based on the outermost electrode sheet of the battery cell 20 being the negative electrode sheet, and the connection needle and the positive electrode terminal are used as examples. In the case where the outermost electrode sheet of the battery cell 20 is the positive electrode sheet, the connection needle and the negative electrode terminal need to be connected. The specific test process is similar and will not be repeated here for the sake of brevity.

[0100] Figure 7 and Figure 8 A possible specific implementation of the method 100 of the needle penetration test is shown.

[0101] It is understandable 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.

[0102] The pretreatment includes taking photos of the battery cell to be tested, testing the voltage, internal resistance and weight, recording the state of the battery cell 20 before the test, etc.; adjusting the SOC, for example, the battery cell 20 can be charged to the cut-off voltage of the battery cell 20 based on a current of not less than 1 / 3C, and left to stand for 1 to 2 hours to stabilize the battery cell 20. In the case where the battery cell 20 is a hard-shell battery cell, it is also necessary to perform peeling and other treatments to remove the shell of the test part, that is, peeling means reserving a certain diameter, for example, at least 20 mm or at least 10 mm, of the avoidance hole at the position for the needle to pierce the shell of the battery cell 20.

[0103] As an example, Figure 8 As shown, the battery cell 20 can be fixed by a clamp 51, and a certain diameter, for example, at least 20 mm or at least 10 mm, of the position for the puncture needle to pierce is reserved on the clamp 51.

[0104] Optionally, a high temperature resistant steel needle with an insulating stopper 52 can be selected as the puncture needle 10. The diameter of the puncture 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 puncture needle 10 should be smooth and free of rust, oxide layer and oil. The moving speed of the puncture needle 10 is, for example, less than or equal to 0.1 mm / s, and the puncture needle 10 is inserted in a direction perpendicular to the plate of the battery cell 20, and the insertion position is close to the geometric center of the punctured surface.

[0105] 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.

[0106] Connect the positive electrode terminal of the battery cell 20 to the needle 10 through a voltage line and set the parameters. Figure 7 and Figure 8 The outermost second electrode sheet 232 is taken as the negative electrode sheet as an example. Before the test, the battery cell to be tested can be charged to a predetermined SOC according to the charging method in the relevant standard. For example, in order to make the test conditions more stringent, the battery cell 20 is usually charged to 100% SOC.

[0107] like Figure 8 As shown, in step 101, the parameters of the acupuncture test are set, such as setting the above-mentioned preset voltage, predetermined depth and other parameters.

[0108] In step 102, it is determined that a needle stick test is started.

[0109] 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.

[0110] 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.

[0111] If the voltage exceeds the predetermined voltage, step 105 is executed.

[0112] 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 initial insertion position of the needle 10, and the needle is controlled to continue moving with the initial insertion position as the starting point.

[0113] 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.

[0114] In step 106, it is determined whether the needle 10 has moved to a predetermined depth from the initial insertion position.

[0115] 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.

[0116] In step 107, the needle 10 is controlled to stop.

[0117] After that, 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 1 hour, at the test environment temperature to see whether fire, explosion, etc., occur in the battery cell 20.

[0118] In step 108, it is determined that the needle stick test is finished.

[0119] The puncture needle 10 is removed, and the battery cell 20 is discharged to a specified discharge termination voltage, and the battery cell 20 is disassembled and the number of short-circuit layers is recorded.

[0120] It can be seen that based on the above-mentioned needle penetration test process, the starting penetration position of the needle 10 when the needle 10 touches or penetrates the outermost second pole piece 232 can be accurately determined, and the needle 10 is controlled to continue to move based on the starting penetration position until it penetrates to a predetermined depth of the battery cell 20. In this way, there is no need to perform complex modifications on the battery cell 20, and the relationship between the physical structure and voltage of the battery cell 20 can be used to accurately and conveniently complete the needle penetration test, which can improve the test accuracy and meet the test requirements for different penetration depths.

[0121] The present application also provides a device 200 for acupuncture testing, such as Fig. 9 As shown, the device 200 includes a processing module 40 and a detection module 30 .

[0122] The processing module 40 is used to control the needle 10 to move in the direction of piercing the battery cell 20. The detection module 30 is used 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 also used to continue to control the needle 10 to penetrate a predetermined depth when the voltage between the needle 10 and the first electrode terminal of the battery cell 20 exceeds a preset voltage.

[0123] The preset voltage is, for example, between 0.5V and 1.5V, such as 1V.

[0124] In some embodiments, the battery cell 20 includes a first pole piece 231 and a second pole piece 232 that are overlapped, and the pole piece located at the outermost layer is the second pole piece 232. The first electrode terminal is an electrode terminal connected to the first pole piece 231, and the polarities of the first pole piece 231 and the second pole piece 232 are opposite.

[0125] In some embodiments, the predetermined depth is determined according to the number of layers of the electrode sheet that need to be penetrated in the needle penetration test.

[0126] In some embodiments, the predetermined depth is determined according to the number of electrode layers to be penetrated, the thickness of the first electrode 231 , and the thickness of the second electrode 232 .

[0127] 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 film 233 between the first pole piece 231 and the second pole piece 232 and / or a preset gap value.

[0128] In some embodiments, when the number of layers is 1, the predetermined depth is L 1 , C+S+D≤L 1 ≤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.

[0129] In some embodiments, the processing module 40 is further configured to control the battery cells 20 to be charged to a predetermined SOC.

[0130] 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 refer to the above description of the method 100, and for the sake of brevity, they are not repeated here.

[0131] The present application also provides a device for a needle puncture test, such as Fig.10 As shown, the device 300 includes a processor 310, and the processor 310 is used to execute the computer instructions stored in the memory 320, so that the device implements the method 100 of the acupuncture test described in any of the above embodiments. The device 300 can be, for example, a host computer. Optionally, the device 300 also includes a memory 320 for storing computer instructions. The memory 320 can be a separate device independent of the processor 310, or it can be integrated in the processor 310.

[0132] Alternatively, if Fig.10 As shown, 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.

[0133] It should be understood that the processor of the embodiment of the present application may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method embodiment can be completed by the hardware integrated logic circuit or software instructions in the processor. The above processor can be a general processor, a digital signal processor (digital signal processor, DSP), an application specific integrated circuit (application specific integrated circuit, ASIC), a field programmable gate array (field programmable gate array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. It can implement or execute the methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general processor can be a microprocessor or any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined and executed. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0134] It can be understood that the memory in the embodiments of the present application can be a volatile memory or a non-volatile memory, or include both volatile and non-volatile memories. Among them, the non-volatile memory can 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 can 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 (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.

[0135] 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 .

[0136] It should be noted that, under the premise of no conflict, the various embodiments described in this application and / or the technical features in each embodiment can be arbitrarily combined with each other, and the technical solution obtained after the combination should also fall within the protection scope of this application.

[0137] 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.

[0138] Those of ordinary skill 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 to be beyond the scope of this application.

[0139] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the above method embodiments and will not be repeated here.

[0140] In the several embodiments provided in the present 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 only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, 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.

[0141] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment 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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