Polar Plate Flexibility Testing Method and Testing Equipment

Abstract

An embodiment of the present application discloses a method and a testing device for testing the flexibility of a pole piece. The testing method includes the following steps: measuring the initial length L0, width W, thickness T, and initial resistance Z0 of the pole piece, calculating the initial resistivity P0 of the pole piece, and recording the initial elongation A0 of the pole piece; stretching the pole piece and measuring the length Ln and resistance Zn of the pole piece after stretching n times; calculating the resistivity Pn of the pole piece after stretching, and calculating the elongation An of the pole piece after stretching; determining whether the resistivity has a sudden change. If so, taking the elongation An corresponding to the sudden change of the resistivity Pn as a parameter characterizing the flexibility of the pole piece. The embodiment of the present application can quantitatively measure the flexibility of the pole piece, and the result is more accurate.

Description

Technical Field

[0001] This application belongs to the field of battery testing. Specifically, this application relates to a method for testing the flexibility of a pole piece and a device for testing the flexibility of a pole piece. Background Art

[0002] Lithium-ion secondary batteries are widely used in electric vehicles and various electronic products due to their advantages such as high energy density, high output power, long cycle life, and low environmental pollution, and occupy the core position of power batteries. The flexibility of the positive and negative pole pieces of lithium-ion secondary batteries has a crucial impact on the rolling process, slitting process, and winding process. For electrode sheets with poor flexibility, during the processing of the rolling, slitting, and winding processes, electrode sheet material loss, foil leakage, and tape breakage will occur, which not only reduces the production efficiency of the battery core, increases the production cost of the enterprise, but also brings risks to the safety of lithium-ion batteries; therefore, the detection of the flexibility of electrode sheets is of great significance for the preparation and production of lithium-ion batteries.

[0003] In the existing technology for testing the flexibility of a pole piece, the pole piece is placed on a roller, and then a heavy object is hung, and then the human eye observes whether there are cracks. On the premise that no cracks occur in the pole piece, the flexibility of the pole piece is judged by the smallest diameter roller that can be used. In such a testing method, the subjective judgment of people accounts for a relatively large proportion. For example, it is difficult to have a digital record of whether there are cracks, and the diameter of the used roller is fixed and cannot be continuously changed. The testing method is relatively rough and it is difficult to quantify the cracking data. Summary of the Invention

[0004] An object of an embodiment of this application is to provide a new technical solution for testing the flexibility of a pole piece, so that the testing process can be quantified and more accurate.

[0005] According to the first aspect of the embodiments of this application, a method for testing the flexibility of a pole piece is provided, including the following steps:

[0006] Measure the initial length L0, width W, thickness T, and initial resistance Z0 of the pole piece, calculate the initial resistivity P0 of the pole piece, and record the initial elongation A0 of the pole piece;

[0007] Stretch the pole piece, and measure the length Ln and resistance Zn of the stretched pole piece n times;

[0008] Calculate the resistivity Pn of the stretched pole piece, and calculate the elongation An of the stretched pole piece;

[0009] Judge whether the resistivity has changed suddenly. If so, use the elongation An corresponding to the sudden change of the resistivity Pn as a parameter characterizing the flexibility of the pole piece.

[0010] Optionally, the resistivity mutation refers to that the rising rate of the resistivity exceeds a first predetermined value.

[0011] Optionally, the resistivity mutation refers to that the value of the resistivity exceeds a second predetermined value.

[0012] Optionally, the electrode sheet is obtained by coating electrode sheet slurry on a substrate and then drying.

[0013] Optionally, the breaking elongation rate of the substrate is greater than that of copper foil or aluminum foil, where the breaking elongation rate is: when a film sample is subjected to a breaking tensile test, the percentage increase in the length of the film sample when the film sample breaks.

[0014] Optionally, the electrode sheet slurry is coated on one side or both sides of the substrate.

[0015] Optionally, for the method of testing the flexibility of the electrode sheet, the electrode sheet is stretched until it breaks.

[0016] Optionally, the tensile force applied during the stretching process is constant.

[0017] According to another aspect of the embodiments of the present application, a device for testing the flexibility of an electrode sheet is provided, including:

[0018] A first clamping mechanism and a second clamping mechanism, the first clamping mechanism and the second clamping mechanism are used to respectively clamp both ends of the electrode sheet in the length direction;

[0019] A resistance measurement module, the resistance measurement module is used to measure the resistance of the electrode sheet;

[0020] A position detection module, the position detection module is used to measure the distance between the first clamping mechanism and the second clamping mechanism;

[0021] A driving mechanism, the driving mechanism is used to drive the first clamping mechanism and the second clamping mechanism to move away from each other, so as to stretch the electrode sheet;

[0022] A data collection and calculation module, the data collection and calculation module is electrically connected to the resistance measurement module and the position detection module, so as to collect the length and resistance of the electrode sheet during the stretching process, and calculate the resistivity and elongation rate of the electrode sheet during the stretching process according to the length, the resistance, the width of the electrode sheet, and the thickness of the electrode sheet.

[0023] Optionally, the device for testing the flexibility of the electrode sheet further includes a tensile force detection module, the tensile force detection module is electrically connected to the first clamping mechanism, the second clamping mechanism and the driving mechanism, so as to detect the tensile force between the first clamping mechanism and the second clamping mechanism, and feed back the tensile force to the driving mechanism.

[0024] Optionally, the first clamping mechanism and the second clamping mechanism are made of a conductive material, and the resistance measurement module is electrically connected to the first clamping mechanism and the second clamping mechanism.

[0025] Optionally, the pole piece flexibility testing device further includes a display module, and the display module is electrically connected to the data collection and calculation module, so as to display the resistivity and the elongation rate on the display module.

[0026] Optionally, the pole piece flexibility testing device further includes a judgment module, and the judgment module is electrically connected to the data collection and calculation module. When the resistivity undergoes a sudden change, the judgment module marks the elongation rate at the time of the sudden change as a parameter characterizing the flexibility of the pole piece.

[0027] One technical effect of the present application is that the stretching process can be a continuous process. During the stretching process, the resistivity and elongation rate of the pole piece are measured and calculated multiple times. By judging the sudden change of the resistivity, it is determined that the elongation rate of the pole piece corresponding to the sudden change has reached the flexibility limit of the pole piece. At this time, this elongation rate is used as a parameter characterizing the flexibility of the pole piece, so as to characterize the flexibility of the pole piece in a quantitative manner, and the test result is more accurate.

[0028] Other features and advantages of the present application will become clear through the following detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings. Description of the Drawings

[0029] The drawings incorporated in the specification and constituting a part of the specification illustrate embodiments of the present application, and together with the description are used to explain the principles of the present application.

[0030] Figure 1 It is a flowchart of a method for testing the flexibility of a pole piece according to an embodiment of the present application;

[0031] Figure 2 It is a flowchart of a method for testing the flexibility of a pole piece according to another embodiment of the present application;

[0032] Figure 3 It is a working principle diagram of a pole piece flexibility testing device according to an embodiment of the present application;

[0033] Figure 4 It is a relationship diagram of elongation rate - resistivity of two test examples according to an embodiment of the present application.

[0034] Wherein: 0, pole piece; 01, slurry coating; 02, substrate; 1, first clamping mechanism; 2, second clamping mechanism; 3, position detection module; 4, data collection and calculation module; 5, driving mechanism; 6, resistance measurement module. Detailed Embodiments

[0035] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0036] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present application or its application or use.

[0037] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the specification.

[0038] In all the examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0039] It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, further discussion thereof is not required in subsequent drawings.

[0040] Reference Figure 1 , which shows a method for testing the flexibility of a pole piece, including the following steps:

[0041] S1. Cut the pole piece to obtain the pole piece to be detected. First, measure the initial length L0, width W, thickness T, and initial resistance Z0 of the pole piece. The initial length L0, width W, thickness T, and initial resistance Z0 represent the initial state parameters of the pole piece when it is not stretched. Calculate the initial resistivity P0 of the pole piece according to the equation P0 = Z0 * (T * W) / L0, and record the initial elongation rate A0 of the pole piece. At this time, A0 = 0%;

[0042] S2. Stretch the pole piece. At the first moment after stretching, measure the resistance Z1 of the pole piece and the length L1 of the stretched pole piece.

[0043] S3. Calculate the resistivity P1 of the pole piece at the first measurement during the stretching process according to the equation P1 = Z1 * (T * W) / L1, and calculate the elongation rate A1 of the pole piece at the first measurement during the stretching process according to the equation A1 = (L1 / L0 - 1) * 100%.

[0044] For greater accuracy, stretching and measurement can be continued in step S2. Measure the length Ln and resistance Zn of the pole piece after stretching n times. Calculate the resistivity Pn obtained after the nth stretching of the pole piece during the stretching process according to the equation Pn = Zn * (T * W) / Ln, and calculate the elongation An after the nth stretching of the pole piece during the stretching process according to the equation An = (Ln / L0 - 1) * 100%. It should be noted that if the measurement in step S1 is regarded as the 0th measurement, the equations Pn = Zn * (T * W) / Ln and An = (Ln / L0 - 1) * 100% still hold. At this time, P0 = Z0 * (T * W) / L0 and A0 = (L0 / L0 - 1) * 100% = 0%.

[0045] Step S2 and step S3 can be reciprocally cycled, that is, measure the length and resistance once and calculate the resistivity and elongation of the pole piece after one stretching; or n values can be measured at once in step S2 and then calculated together in step S3. Both methods fall within the protection scope of this embodiment.

[0046] A series of Z1, Z2, Z3... Zn and the corresponding L1, L2, L3... Ln are obtained according to the time sequence, and then the corresponding resistivity P1, P2, P3... Pn and elongation A1, A2, A3... An can be calculated. Therefore, a relationship graph of resistivity and elongation can be made, as Figure 4 shown.

[0047] S4. Judge whether the resistivity changes suddenly. If the judgment result is yes, go to step S5; otherwise, continue the stretching measurement in step S2.

[0048] S5. Take the elongation An corresponding to the sudden change of the resistivity Pn as a parameter characterizing the flexibility of the pole piece.

[0049] Taking Figure 3 the measured and calculated results as an example, t1 is the calculation result of the elongation-resistivity of the pole piece used in the first test case, and t2 is the calculation result of the elongation-resistivity of the pole piece used in the second test case.

[0050] From Figure 3 it can be seen that among the data points of t1, the resistivity suddenly increases from 20.8 Ωcm (ohm centimeter), and the corresponding elongation at this time is 5.6%. Among the data points of t2, the resistivity suddenly increases from 21.1 Ωcm (ohm centimeter), and the corresponding elongation at this time is 2.7%. Therefore, 5.6% is used as a parameter characterizing the flexibility of the pole piece in the t1 test case, and 2.7% is used as a parameter characterizing the flexibility of the pole piece in the t2 test case. Obviously, the flexibility of test case 1 is higher than that of test case 2.

[0051] The advantage of adopting the above method is that the principle of stretching can be directly used for flexibility evaluation. The pole piece is stretched until a resistivity mutation occurs. At this time, the resistivity mutation can be considered to be caused by cracks in the pole piece. The elongation corresponding to the occurrence of cracks can represent the flexibility of the pole piece. During the whole testing process, the stretching process can be a continuous process. During the stretching process, the resistivity and elongation of the pole piece are measured and calculated multiple times. Since the pole piece is a porous electrode and there is a conductive network inside the pole piece, the cracks in the pole piece will cause changes in the resistivity of the pole piece. Therefore, the flexibility of the pole piece can be evaluated by detecting the change of the resistivity of the pole piece with the stretching elongation rate. The corresponding elongation rate is judged through the resistivity mutation, so as to quantitatively characterize the flexibility of the pole piece, and the test result is more accurate.

[0052] As a preferred solution, the resistivity mutation means that the rising rate of the resistivity Pn exceeds a first predetermined value. For example, in the case of sampling measurement once per second (s), the resistivity measured at the 60th second is 20 Ωcm, and the resistivity measured at the 61st second is 25 Ωcm. Then the rising rate of the resistivity Pn is 5 Ωcm / s. Assuming that the first predetermined value is 3 Ωcm / s, it is judged that when 5 Ωcm / s > the first predetermined value of 3 Ωcm / s, the resistivity mutates at the 61st second. The first predetermined value can be set as needed.

[0053] As another preferred solution, the resistivity mutation means that the value of the resistivity Pn exceeds a second predetermined value. For example, in the initial state, the resistivity of t1 is 20.8 Ωcm. Thus, it can be set that when the resistivity of t1 rises to the second predetermined value of 25 Ωcm, it is judged that the resistivity mutates at this time. The second predetermined value can also be set as needed.

[0054] In Figure 1 the shown embodiment, the pole piece to be tested can be a real pole piece. In fact, the flexibility of the pole piece is related to the following factors: the pole piece slurry formula (including material types), the pole piece thickness, and the manufacturing process. Among them, the flexibility of the pole piece formula itself is the most critical factor. In order to test the pole piece formula before actually producing the pole piece and save production costs, Figure 2 the shown embodiment makes a further improvement on Figure 1 the shown embodiment.

[0055] In Figure 2 the shown embodiment, before the test, step S01 is carried out: the pole piece slurry is coated on the substrate and then dried to obtain the pole piece to be tested.

[0056] The elongation at break of the preferred substrate is greater than that of the copper foil or aluminum foil. This is because, in actual electrode sheets, copper foil or aluminum foil with an elongation at break of 2-5% is generally used as the substrate, while in the embodiments of the present application, a substrate with a higher elongation at break is used, such as an insulating film with an elongation at break greater than 10% (such as polymer films like PP, PE, PET, PI, etc., with a thickness of 2-2000 μm). This can expand the test range of the flexibility of the electrode sheet slurry formulation and also increase the relative value of the change in resistivity Pn, enhancing the test resolution. In this article, the elongation at break is: when a tensile fracture test is carried out, the percentage increase in the length of the film sample when the film sample fractures, and this value is used to measure the elongation ability of the film sample before fracture. For example, if the elongation at break of the film sample is 10%, it means that the length of the film sample at fracture is 1.1 times the original length, or in other words, when the film sample is stretched to fracture, the length increases by 10% compared to the original length before stretching. The film sample can be the copper foil or aluminum foil or polymer films such as PP, PE, PET, PI, etc. described above and other substrates.

[0057] In step S01, the electrode sheet slurry can be coated on one or both sides of the substrate.

[0058] In Figure 1 and Figure 2 In the electrode sheet flexibility test method shown, the electrode sheet can be stretched until it fractures. Therefore, in Figure 3 the sampling point does not disappear immediately after the resistivity mutation.

[0059] As a preferred solution, the pulling force applied during the stretching process is constant. For example, the pulling force is maintained at 10 Newtons, which can ensure that the electrode sheet is stretched smoothly and the test effect is more accurate.

[0060] Refer to Figure 3 , which shows an electrode sheet flexibility test device that can implement the electrode sheet flexibility test method described above. In Figure 3 the shown electrode sheet 0 includes a slurry coating 01 and a substrate 02. That is to say, the electrode sheet 0 used in this embodiment is formed by coating the electrode sheet slurry on the substrate 02, but this embodiment does not exclude the use of a real electrode sheet solution. At the same time, the electrode sheet 0 is the object to be tested and is not part of the electrode sheet flexibility test device.

[0061] The electrode sheet flexibility test device includes:

[0062] A first clamping mechanism 1 and a second clamping mechanism 2. The first clamping mechanism 1 and the second clamping mechanism 2 are used to respectively clamp both ends of the electrode sheet in the length direction, that is, both ends of the electrode sheet in the Y direction shown in the figure. In Figure 3Among them, the two ends of the pole piece in the X direction define the thickness T of the pole piece, the two ends of the pole piece in the Y direction define the length Ln of the pole piece, and the two ends of the pole piece in the direction perpendicular to the paper surface define the width W of the pole piece.

[0063] The resistance measurement module 6 is used to measure the resistance of the pole piece 0. The resistance measurement module 6 can be directly connected to the pole piece 0 for resistance measurement, or can be connected to the first clamping mechanism 1 and the second clamping mechanism 2.

[0064] The position detection module 3 is used to measure the distance between the first clamping mechanism 1 and the second clamping mechanism 2, and this distance is equal to the length Ln of the pole piece during the stretching process;

[0065] The driving mechanism 5 is used to drive the first clamping mechanism 1 and the second clamping mechanism 2 to move away from each other, so as to apply a tensile force to the pole piece 0 for stretching.

[0066] The data collection and calculation module 4 is electrically connected to the resistance measurement module 6 and the position detection module 3, so as to collect the length Ln and resistance Zn of the pole piece during the stretching process, and calculate the resistivity and elongation of the pole piece during the stretching process according to the length Ln, the resistance Zn, the width W of the pole piece, and the thickness T of the pole piece. The specific calculation method has been described above, so it will not be elaborated here.

[0067] As a preferred solution, the pole piece flexibility test device further includes a tensile force detection module (not shown). The tensile force detection module is electrically connected to the first clamping mechanism 1, the second clamping mechanism 2 and the driving mechanism 5, so as to detect the tensile force between the first clamping mechanism 1 and the second clamping mechanism 2, and feed back the tensile force to the driving mechanism 5, so that the tensile force between the first clamping mechanism 1 and the second clamping mechanism 2 can be maintained in a constant state.

[0068] As a preferred solution, the first clamping mechanism 1 and the second clamping mechanism 2 are made of conductive materials. For example, copper alligator clips, copper screw fastening and other methods are used. At this time, the resistance measurement module 6 can be electrically connected to the first clamping mechanism 1 and the second clamping mechanism 2, so the structure is simpler and the measurement is more accurate.

[0069] Optionally, the above-mentioned pole piece flexibility test device further includes a display module (not shown). The display module is electrically connected to the data collection and calculation module 4, so as to display the resistivity Pn and elongation An on the display module, Figure 4 to output the results more intuitively.

[0070] Optionally, the flexible pole piece testing device further includes a judgment module (not shown). The judgment module is electrically connected to the data collection and calculation module. When the judgment module determines that the resistivity Pn undergoes a sudden change, the judgment module marks the elongation An at the time of the sudden change as a parameter characterizing the flexibility of the pole piece, and displays it in a prominent mark such as red or yellow.

[0071] In addition to Figure 3 the components shown, the flexible pole piece testing device further includes other necessary mechanical / electrical components for testing, such as a bottom plate, a counterweight, a vertical bracket, a guide rail, a wire, a data transmission line, a console, a signal amplifier, an input / output device, etc. For the sake of simplicity, Figure 3 they are not shown and only a principle description is given.

[0072] Refer to Figure 4 , and next, taking a specific test example as an example, the flexible pole piece testing method and device will be described, but the specific parameters therein are not used to limit this embodiment.

[0073] The specific components selected for the flexible pole piece testing device are as follows: The resistance measurement module 6 selects an AC impedance tester with a test frequency of 1000 Hz. Of course, a DC impedance tester can also be selected. The driving mechanism 5 selects a servo motor. The sampling frequency of the data collection and calculation module 4 is selected as 100 ms.

[0074] Test Example 1:

[0075] Lithium manganate, conductive carbon black, and PVDF (model HSV900) are proportioned in a weight ratio of 95:2:3 and homogenized using NMP solvent, coated on a PET substrate with a thickness of 50 μm, dried and then rolled to a compaction of 3.0 g / cm³, and then cut into a test pole piece with a size of 200 mm * 20 mm.

[0076] Fix the pole piece between the first clamping mechanism 1 and the second clamping mechanism 2, and perform the test at a stretching speed of 1 mm / min.

[0077] The data collection and calculation module 4 plots the elongation An and the resistivity Pn to obtain the t1 data point set as shown in Figure 4 , and the point where the resistivity Pn suddenly increases can be found from Figure 4 it.

[0078] Test Example 2:

[0079] Change the PVDF model from HSV900 to Solvay5130, and the other formulations are the same as in Test Example 1, and the test process is also the same as in Test Example 1.

[0080] The test results are shown in Table 1 and Figure 4 as follows:

[0081] It can be seen that when the resistivity mutation point of Test Example 1 is at an elongation of 5.3%, the resistivity mutation point of Test Example 2 is 2.1%. Therefore, the flexibility of Test Example 1 is better than that of the formulation of Test Example 2.

[0082] Table 1

[0083]

[0084] In the above embodiments, the differences between the various embodiments are mainly described. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. For the sake of brevity, it will not be elaborated here.

[0085] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are only for illustration and not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A method for testing the flexibility of a pole piece, characterized in that, It includes the following steps: Measure the initial length L0, width W, thickness T, and initial resistance Z0 of the electrode sheet, calculate the initial resistivity P0 of the electrode sheet, and record the initial elongation A0 of the electrode sheet; Stretch the electrode sheet and measure the length Ln and resistance Zn of the stretched electrode sheet n times; Calculate the resistivity Pn of the stretched electrode sheet and calculate the elongation An of the stretched electrode sheet, where Pn = Zn * (T * W) / Ln and An = (Ln / L0 - 1) * 100%; Make a relationship graph of the resistivity and the elongation, and determine whether the resistivity undergoes a mutation. If so, use the elongation An corresponding to the mutation of the resistivity Pn as a parameter characterizing the flexibility of the electrode sheet.

2. The method for testing the flexibility of the pole piece according to claim 1, wherein The resistivity mutation refers to the case where the rising rate of the resistivity exceeds a first predetermined value.

3. The method for testing the flexibility of the pole piece according to claim 1, wherein, The resistivity mutation refers to the case where the value of the resistivity exceeds a second predetermined value.

4. The method for testing the flexibility of the electrode sheet according to claim 1, wherein, The electrode sheet is obtained by coating an electrode paste on a substrate and then drying.

5. The method for testing the flexibility of the electrode sheet according to claim 4, characterized in that, The breaking elongation of the substrate is greater than that of copper foil or aluminum foil, where the breaking elongation is: when a film sample is subjected to a breaking tensile test, the percentage increase in the length of the film sample when the film sample breaks.

6. The method for testing the flexibility of the pole piece according to claim 4, wherein The electrode paste is coated on one side or both sides of the substrate.

7. The method for testing the flexibility of the pole piece according to claim 1, wherein Stretch the electrode sheet until it breaks.

8. The method for testing the flexibility of the pole piece according to claim 1, characterized in that, The pulling force applied during the stretching process is constant.

9. A pole piece flexibility testing device, characterized in that, It includes: A first clamping mechanism and a second clamping mechanism, where the first clamping mechanism and the second clamping mechanism are used to respectively clamp both ends of the electrode sheet in the length direction; A resistance measurement module, which is used to measure the resistance of the electrode sheet; A position detection module, which is used to measure the distance between the first clamping mechanism and the second clamping mechanism; A driving mechanism, which is used to drive the first clamping mechanism and the second clamping mechanism to move away from each other, thereby stretching the electrode sheet; A data collection and calculation module, which is electrically connected to the resistance measurement module and the position detection module, so as to collect the length Ln and resistance Zn of the electrode sheet during the stretching process, and calculate the resistivity Pn and elongation An of the electrode sheet during the stretching process according to the length Ln, the resistance Zn, the width W of the electrode sheet, and the thickness T of the electrode sheet, where Pn = Zn * (T * W) / Ln and An = (Ln / L0 - 1) * 100%, and L0 is the initial length of the electrode sheet; A judgment module, which is electrically connected to the data collection and calculation module. According to the relationship graph of the resistivity and the elongation, when the resistivity undergoes a mutation, the judgment module marks the elongation at the time of mutation as a parameter characterizing the flexibility of the electrode sheet.

10. The pole piece flexibility testing device according to claim 9, characterized in that, It further includes a pulling force detection module, which is electrically connected to the first clamping mechanism, the second clamping mechanism, and the driving mechanism, so as to detect the pulling force between the first clamping mechanism and the second clamping mechanism and feed back the pulling force to the driving mechanism.

11. The pole piece flexibility testing device according to claim 9, characterized in that, The first clamping mechanism and the second clamping mechanism are made of conductive materials, and the resistance measurement module is electrically connected to the first clamping mechanism and the second clamping mechanism.

12. The pole piece flexibility testing device according to claim 9, characterized in that, It further includes a display module, and the display module is electrically connected to the data collection and calculation module, so as to display the resistivity and the elongation on the display module.

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