Method for testing stripping force of diaphragm

Abstract

The invention provides a method for testing the stripping force of a diaphragm, which comprises the following steps of: fixing the diaphragm to be tested on a test plate, attaching a fixed part of the diaphragm to be tested to the test plate, not contacting a free part of the diaphragm to be tested with the test plate, folding the free part along a folding line, laminating and contacting the free part with the fixed part, and clamping one end of the free part into an upper clamp of a tensile machine, one end of the test plate is clamped into the lower clamp, the speed and the distance of the tensile machine are set, and the free part is stretched, so that the stripping force of the diaphragm to be tested can be accurately measured, each laboratory can be ensured to operate according to the same process, the test method of the stripping force of the diaphragm is standardized, the test difference of different laboratories is reduced, and the test efficiency is improved. And the consistency of test results is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a method for testing the peeling force of a diaphragm. Background Art

[0002] In the structure of lithium batteries, the separator is a core component that ensures key performance such as battery safety, capacity and cycle life. It not only effectively prevents contact between the positive and negative electrodes of the battery, but also allows electrolyte ions to pass smoothly to support the normal operation of the battery.

[0003] As consumers' demand for higher battery capacity, longer battery life and more efficient energy output continues to grow, the thinning and lightweight of separators has become a development trend to improve the energy density and overall performance of lithium batteries. In this process, the peel strength between the separator and the substrate has become one of the important testing indicators; however, there is currently no unified test method for separator peel strength, resulting in a lack of consistency in the evaluation of separator peel strength under different production and testing conditions. Summary of the invention

[0004] The embodiment of the present application provides a method for testing the peeling force of a diaphragm, which is used to solve or at least partially solve the deficiencies of the above-mentioned background technology.

[0005] The present application provides a method for testing the peeling force of a separator, comprising:

[0006] Provide the diaphragm to be tested;

[0007] The diaphragm to be tested is fixed on the test board, wherein the diaphragm to be tested comprises a fixed portion and a free portion connected to each other, and a fold line located between the fixed portion and the free portion, the fixed portion is in contact with the test board, the free portion is not in contact with the test board, and the length of the free portion is greater than the length of the fixed portion;

[0008] Folding the free portion in half along the folding line so that the free portion and the fixed portion are in contact and stacked, wherein at least a portion of the free portion does not overlap with the test board;

[0009] Clamp one end of the free portion away from the test plate on the upper clamp of the tensile machine, and clamp one end of the test plate away from the free portion on the lower clamp of the tensile machine, and the lower clamp does not contact the diaphragm to be tested;

[0010] The peeling stretching speed and the peeling stretching distance of the tensile testing machine are set, the free portion is stretched, the diaphragm to be tested is peeled off from the test plate, and the peeling force is recorded.

[0011] In one embodiment, the step of fixing the diaphragm to be tested on a test board, wherein the diaphragm to be tested includes a fixed portion and a free portion connected to each other, and a fold line between the fixed portion and the free portion, wherein the fixed portion is in contact with the test board, the free portion is not in contact with the test board, and the length of the free portion is greater than the length of the fixed portion, comprises:

[0012] Attach the double-sided tape to the test board, and tear off the isolation paper on the side of the double-sided tape away from the test board;

[0013] The diaphragm to be tested is placed on the second surface of the double-sided tape, the fixed portion is in contact with the double-sided tape, and the free portion is not in contact with the double-sided tape, wherein the orthographic projection of the fixed portion on the test board is within the orthographic projection of the double-sided tape on the test board.

[0014] In one embodiment, the step of attaching the double-sided adhesive tape to the test board and tearing off the isolation paper on the side of the double-sided adhesive tape away from the test board comprises:

[0015] Provide a double-sided adhesive tape, the double-sided adhesive tape comprising a first side and a second side arranged opposite to each other, and release paper is attached to both the first side and the second side;

[0016] Tear off the release paper on the first side of the double-sided tape, and stick the first side of the double-sided tape on the test board;

[0017] Rolling the second side of the double-sided adhesive tape multiple times using a pressure roller;

[0018] Tear off the release paper on the second side of the double-sided adhesive.

[0019] In one embodiment, the step of placing the diaphragm to be tested on the second surface of the double-sided tape, the fixed portion being in contact with the double-sided tape, and the free portion not being in contact with the double-sided tape, wherein the orthographic projection of the fixed portion on the test board is within the orthographic projection of the double-sided tape on the test board comprises:

[0020] The fixed portion is attached to the second surface of the double-sided tape, and the free portion is not in contact with the double-sided tape;

[0021] Laminating the release paper with the second side of the double-sided tape, laminating the release paper with the second side of the double-sided tape, wherein the fixing portion is located between the double-sided tape and the release paper, and the orthographic projection of the fixing portion on the double-sided tape is located within the orthographic projection of the release paper on the test board;

[0022] Using a pressing roller to press the side of the release paper away from the fixing portion for multiple times;

[0023] The release paper is torn off.

[0024] In one embodiment, the length of the double-sided tape is greater than or equal to the length of the fixing portion, and is less than the length of the diaphragm to be tested, and the width of the double-sided tape is greater than the width of the diaphragm to be tested.

[0025] In one embodiment, the length of the double-sided tape is greater than or equal to 80 mm and less than or equal to 100 mm, and the width of the double-sided tape is 20 mm.

[0026] In one embodiment, the step of providing a diaphragm to be tested includes:

[0027] Fix the diaphragm substrate on the workbench of the diaphragm slitting machine;

[0028] The membrane substrate is cut by the membrane slitting machine to form a plurality of membrane strips, and at least one membrane strip located in the middle of the plurality of membrane strips is selected as the membrane to be tested.

[0029] In one embodiment, the width of the diaphragm to be tested is 15 mm, the length of the diaphragm to be tested is 200 mm, the length of the fixed portion is 80 mm, and the length of the free portion is 120 mm.

[0030] In one embodiment, the peeling and stretching speed of the tensile testing machine is 50 mm / min, and the peeling and stretching distance is 160 mm.

[0031] In one embodiment, the peeling stretching speed and peeling stretching distance of the tensile testing machine are set, the free portion is stretched, the diaphragm to be tested is peeled off from the test plate, and in the step of recording the peeling force, the termination force of the tensile testing machine is 50N, and the inlet force of the tensile testing machine is 0.1N.

[0032] Beneficial effects of the embodiments of the present application: The embodiments of the present application provide a method for testing the peeling force of a membrane, wherein the membrane to be tested is fixed on a test plate, the fixed portion of the membrane to be tested fits the test plate, and the free portion of the membrane to be tested does not contact the test plate, the free portion is folded in half along a folding line and in contact with the fixed portion, one end of the free portion is clamped in the upper clamp of a tensile testing machine, one end of the test plate is clamped in the lower clamp, the speed and distance of the tensile testing machine are set, and the free portion is stretched, thereby being able to accurately measure the peeling force of the membrane to be tested, and ensuring that each laboratory can operate according to the same process, standardizing the testing method for the membrane peeling force, reducing the testing differences between different laboratories, and improving the consistency of the test results. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solution in this embodiment, the drawings required for use in the description of the embodiment will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 A flow chart of a method for testing the peeling force of a separator provided in an embodiment of the present application;

[0035] Figures 2 to 6 for Figure 1 Process flow chart of the test method for the peeling force of the diaphragm.

[0036] Description of Reference Numerals

[0037] 10-diaphragm substrate; 20-diaphragm slitting machine; 30-test board; 40-double-sided tape; 50-tensile machine;

[0038] 11-diaphragm to be tested; 111-fixed portion; 112-free portion; 113-fold line;

[0039] 21-working table; 22-fixing member; 23-driving member; 24-supporting part; 231-rocker;

[0040] 51-first clamp; 52-second clamp. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, unless otherwise stated, the directional words such as "upper" and "lower" used generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device.

[0042] Please combine Figure 1 , Figures 2 to 6 ;in, Figure 1 A flow chart of a method for testing the peeling force of a separator provided in an embodiment of the present application; Figures 5 and 6 for Figure 1 Process flow chart of the test method for the peeling force of the diaphragm.

[0043] This embodiment provides a method for testing the peeling force of a separator, which is used for testing the peeling strength of a battery separator. The method for testing the peeling force of a separator comprises the following steps:

[0044] Step S10: providing a diaphragm 11 to be tested.

[0045] In one embodiment, the step S10 includes the following steps:

[0046] Step S11: Fix the membrane substrate 10 on the workbench 21 of the membrane slitting machine 20; Figure 2 shown.

[0047] Among them, the shape of the cross-section of the diaphragm substrate 10 includes but is not limited to one of a rectangle or a square. The diaphragm substrate 10 refers to the original material used to make battery diaphragms during the battery production process, and can be cut into final diaphragms according to different size and shape requirements in the battery production process; the diaphragm slitting machine 20 is a device specially used to cut large sheets of diaphragm substrates 10 into small strips or specific shapes. The diaphragm slitting machine 20 can efficiently and accurately cut the diaphragm substrate 10 into strips according to a predetermined width and length.

[0048] It should be noted that the present embodiment does not impose any specific restrictions on the structure of the membrane slitting machine 20, but in order to better illustrate the innovation of the present embodiment, the present embodiment is based on Figure 2 The structure of the membrane slitting machine 20 shown is taken as an example to illustrate the technical solution of this embodiment.

[0049] Specifically, in the step S11, the diaphragm slitting machine 20 includes a workbench 21, a fixing part 22, a cutting part, a driving part 23 and a supporting part 24. The workbench 21 can be composed of a plurality of roller structures. The diaphragm substrate 10 is attached to the surface of the roller. The roller structure can ensure that the diaphragm substrate 10 maintains a stable and smooth movement during the slitting process, which helps to keep the surface of the diaphragm substrate 10 flat and avoid wrinkles or irregular deformation.

[0050] The fixing part 22 includes but is not limited to an iron bolt. The workbench 21 is provided with a mounting hole corresponding to the fixing part 22. By tightening or adjusting the position of the fixing part 22, a certain pressure can be applied to the diaphragm substrate 10 to press it onto the workbench 21 so that it can be stably attached to the surface of the workbench 21.

[0051] It can be understood that by providing a fixing part 22 on the diaphragm substrate 10, the diaphragm substrate 10 can be evenly stressed, avoiding local looseness or tension, and ensuring that the diaphragm substrate 10 is flat and wrinkle-free; at the same time, it can also prevent the diaphragm substrate 10 from any displacement or sliding during the stripping operation, thereby maintaining the stability of the diaphragm substrate 10.

[0052] The cutting member includes but is not limited to a mechanical blade, and is used to precisely cut the diaphragm substrate 10 . The cutting member is located at a gap between adjacent rollers. The diaphragm substrate 10 can be transported by the rollers to the position of the cutting member.

[0053] The driving member 23 includes but is not limited to a rocker 231, which is connected to the workbench 21 and is used to control the conveying direction and speed of the diaphragm substrate 10; wherein, rotating the rocker 231 can orderly convey the diaphragm substrate 10 into the cutting area, so that the isolation substrate maintains tension before reaching the tool, ensuring that the isolation substrate does not wrinkle or sag during the cutting process, thereby improving the cutting accuracy and stability.

[0054] The support portion 24 is used to support the workbench 21 to ensure that the roller structure can remain stable when subjected to force, thereby ensuring the movement accuracy and consistency of the diaphragm substrate 10 during the cutting process and avoiding cutting deviations caused by vibration or instability of the workbench 21. It can be understood that this embodiment does not specifically limit the structure of the support portion 24. Figure 2 Only an exemplary structure is shown in the figure, and the support portion 24 can adopt different forms according to actual needs, such as a bracket, a support rod or a base, so as to ensure the stability of the workbench 21.

[0055] Furthermore, before the diaphragm substrate 10 and the workbench 21 are fixed, the diaphragm substrate 10 can be rotated on the workbench 21 to ensure that the surface of the diaphragm substrate 10 is completely flat and tension-free, thereby avoiding stress deviation caused by uneven surface or uneven tension of the diaphragm substrate 10.

[0056] Step S12: Control the membrane slitting machine 20 to cut the sample to be tested to form multiple membrane strips, and select at least one membrane strip located in the middle position from the multiple membrane strips as the membrane 11 to be tested; the width of the membrane 11 to be tested can be 15 mm, and the length of the membrane 11 to be tested can be 200 mm.

[0057] It is understandable that after the slitting machine cuts the diaphragm substrate 10, the diaphragm strips at different positions may be affected by edge stress or other uneven factors, resulting in the diaphragm strips located at the edge position having different physical properties from the diaphragm strips located in the middle position, thereby introducing deviations; in order to reduce the differences in physical properties caused by the different positions of the diaphragm strips, this embodiment improves the reliability of the test results by selecting at least one of the diaphragm strips located in the middle position as the diaphragm 11 to be tested.

[0058] It should be noted that the technical solution proposed in this embodiment is suitable for application scenarios such as standardized operations of membrane peeling force testing. This embodiment does not specifically limit the type, width and length of the membrane 11 to be tested. However, in order to better illustrate the innovation of this embodiment, this embodiment takes the width of the membrane 11 to be tested as 15 mm and the length of the membrane 11 to be tested as 200 mm as an example to illustrate the technical solution of this embodiment.

[0059] In addition, this embodiment only takes the selection of one of the diaphragm strips located in the middle position as the diaphragm 11 to be tested as an example to illustrate the technical solution of this embodiment; in another embodiment, three of the diaphragm strips located in the middle position can be selected as the diaphragm 11 to be tested, and the peeling force test is performed on these three diaphragms 11 to be tested respectively, so as to further ensure the representativeness and reliability of the test results.

[0060] Step S20: fix part of the diaphragm 11 to be tested on the test board 30, the diaphragm 11 to be tested includes a fixed portion 111 and a free portion 112 connected to each other, a fold line 113 is provided between the fixed portion 111 and the free portion 112, the fixed portion 111 is in contact with the test board 30, and the free portion 112 is separated from the test board 30.

[0061] The cross-section of the diaphragm 11 to be tested may be rectangular, the length of the free portion 112 may be greater than the length of the fixed portion 111 , and at least part of the free portion 112 may not overlap with the test plate 30 , wherein the length of the fixed portion 111 may be 80 mm, and the length of the free portion 112 may be 120 mm.

[0062] The shape of the cross section of the test plate 30 includes but is not limited to a rectangle or a square. The test plate 30 includes but is not limited to a steel plate. The steel plate has high rigidity and stability and can provide a uniform, flat and non-deformable surface. By accurately fixing the diaphragm on the steel plate, the problem of inaccurate peeling force caused by the uneven or unstable surface of the test plate 30 can be avoided.

[0063] It is understandable that in a battery system, the diaphragm is usually in contact with other components of the battery (such as the battery housing, electrodes, current collectors, etc.) and is firmly fixed; therefore, using a steel plate as a test plate 30 can simulate the situation in which the diaphragm is in contact with the battery housing or other structural components during actual battery use, and by testing the strength of the peeling force between the diaphragm and the steel plate, the performance of the diaphragm in actual battery applications can be evaluated.

[0064] In one embodiment, the step S20 includes the following steps:

[0065] Step S21: adhere the double-sided tape 40 to the surface of the test board 30, adhere the diaphragm 11 to be tested to the surface of the double-sided tape 40 away from the test board 30, the fixed portion 111 is adhered to the double-sided tape 40, and the free portion 112 is not in contact with the double-sided tape 40, wherein the orthographic projection of the fixed portion 111 on the test board 30 is located within the orthographic projection of the double-sided tape 40 on the test board 30.

[0066] Specifically, the double-sided tape 40 is attached to the middle position of the test board 30, thereby ensuring that in actual use, the installation of the double-sided tape 40 is not interfered with by the outside world, and can effectively prevent the double-sided tape 40 from being accidentally touched when adjusting the position of the test board 30, thereby avoiding damage to the double-sided tape 40 or loss of stickiness due to improper operation.

[0067] The double-sided tape 40 includes but is not limited to 3M double-sided tape 40. The double-sided tape 40 can provide uniform and stable adhesion. By affixing the double-sided tape 40 to the test board 30, it can ensure that during the subsequent membrane peeling force test, the membrane to be tested 11 is uniformly affixed to the test board 30. Therefore, when the peeling force is applied to the membrane to be tested 11, the peeling force can act uniformly on the entire surface of the membrane to be tested 11, thereby ensuring uniform force transmission during the test.

[0068] It can be understood that the double-sided tape 40 is simpler and easier to operate than the mechanical fixing method in the related art (such as using a clamp or an iron bolt), and does not affect the performance of the diaphragm to be tested 11 itself; at the same time, during the test process, the double-sided tape 40 is used to fix the diaphragm to be tested 11, which can prevent the diaphragm to be tested 11 from slipping or deflecting, thereby ensuring that the test results are accurate and reliable.

[0069] Specifically, the fixing portion 111 and the double-sided tape 40 are fitted together, which can ensure that the diaphragm to be tested 11 remains flat during the test, avoiding uneven tension caused by improper installation, which affects the test of peel strength; at the same time, the orthographic projection of the fixing portion 111 on the test board 30 is located within the orthographic projection of the double-sided tape 40 on the test board 30, which can ensure that the diaphragm to be tested 11 is in a predetermined position during the test and will not shift, thereby further enhancing the accuracy and stability of the test.

[0070] Furthermore, in the step S21, the following steps are included:

[0071] Step S211: providing a double-sided adhesive tape 40, wherein the double-sided adhesive tape 40 comprises a first surface and a second surface arranged opposite to each other, wherein both the first surface and the second surface are pasted with release paper, removing the release paper on the first surface of the double-sided adhesive tape 40, and pasting the first surface of the double-sided adhesive tape 40 on the test board 30, so that the double-sided adhesive tape 40 can be firmly attached to the surface of the test board 30, preventing the double-sided adhesive tape 40 from loosening during the subsequent membrane peeling force test process, thereby ensuring the stability and reliability of the subsequent test process; Figure 3 shown.

[0072] It is understandable that using the double-sided tape 40 with release paper, with the release paper attached to both the first and second sides of the double-sided tape 40, can prevent the double-sided tape 40 from being bonded prematurely during operation, ensuring better flexibility and operability during use.

[0073] Step S212: using a pressing roller to roll the second surface of the double-sided adhesive tape 40 for multiple times.

[0074] Specifically, in step S212, the second side of the double-sided adhesive tape 40 has a release paper, and a natural rolling method can be adopted, and a pressure roller can be used to smoothly and evenly roll the second side of the double-sided adhesive tape 40 back and forth, wherein the pressure roller is in contact with the release paper on the second side of the double-sided adhesive tape 40, and the pressure roller can roll twice.

[0075] It can be understood that by using a pressure roller to roll the second side of the double-sided tape 40 multiple times, the adhesion between the double-sided tape 40 and the test board 30 becomes more uniform and stable, ensuring close contact between the double-sided tape 40 and the test board 30; at the same time, rolling the double-sided tape 40 multiple times can remove bubbles or uneven adhesion that may exist between the contact surfaces of the double-sided tape 40 and the test board 30, thereby reducing the potential risk of uneven adhesion, thereby avoiding errors in subsequent peeling force test results caused by bubbles or uneven adhesion, and improving overall reliability of use.

[0076] Step S213: remove the isolation paper on the second surface of the double-sided tape 40, place the diaphragm 11 to be tested on the second surface of the double-sided tape 40, the fixed portion 111 is in contact with the double-sided tape 40, and the free portion 112 is not in contact with the double-sided tape 40; Figure 4 shown.

[0077] It can be understood that the fixed portion 111 is bonded to the second surface of the double-sided tape 40, and the free portion 112 is not in contact with the double-sided tape 40. Through accurate positioning and bonding, the fixed portion 111 of the diaphragm 11 to be tested is firmly adhered to the test board 30, avoiding errors in the test due to sticking offset or misalignment; at the same time, the free portion 112 is not in contact with the double-sided tape 40, thereby ensuring that the free portion 112 can be peeled off independently without interference during the subsequent peeling test.

[0078] Specifically, in step S213, the release paper on the second side of the double-sided tape 40 is removed to ensure that the second side of the tape is fully exposed, so that the diaphragm 11 to be tested can be accurately attached to the double-sided tape 40 during subsequent testing.

[0079] When the fixing portion 111 and the double-sided tape 40 are attached to each other, the orthographic projection of the fixing portion 111 on the test board 30 is located within the orthographic projection of the double-sided tape 40 on the test board 30, and the free portion 112 is not in direct contact with the double-sided tape 40, thereby avoiding unnecessary adhesion from interfering with the peeling force measurement of the diaphragm 11 to be tested, thereby improving the accuracy of the test results.

[0080] Furthermore, the length of the double-sided tape 40 is greater than or equal to the length of the fixing portion 111, and the length of the double-sided tape 40 is less than the length of the diaphragm to be tested 11, and the width of the double-sided tape 40 is greater than the width of the diaphragm to be tested 11; specifically, the length of the double-sided tape 40 is greater than or equal to 80 mm and less than or equal to 100 mm, and the width of the double-sided tape 40 is 20 mm.

[0081] It should be noted that the technical solution proposed in this embodiment is suitable for application scenarios such as standardized operations of membrane peeling force testing. This embodiment does not specifically limit the type, width and length of the diaphragm 11 to be tested. However, in order to better illustrate the innovation of this embodiment, this embodiment takes the length of the double-sided tape 40 as 80 mm, the width of the double-sided tape 40 as 20 mm, and the length of the double-sided tape 40 equal to the length of the fixing part 111 as an example to illustrate the technical solution of this embodiment.

[0082] It can be understood that by setting the width of the double-sided tape 40 to be larger than the width of the diaphragm 11 to be tested, the double-sided tape 40 with a larger width provides a larger bonding surface for the bonding of the isolation paper in the subsequent testing process, so that the isolation paper can be more firmly attached to the second side of the double-sided tape 40, reducing the possibility of slippage or dislocation during the bonding process. The bonding effect of the isolation paper and the double-sided tape 40 that match the width helps to protect the fixing portion 111 from interference from the pressure roller in subsequent tests.

[0083] Step S214: attaching the isolation paper to the second surface of the double-sided tape 40 , wherein the fixing portion 111 is located between the double-sided tape 40 and the isolation paper, and the orthographic projection of the fixing portion 111 on the double-sided tape 40 is located within the orthographic projection of the isolation paper on the test board 30 .

[0084] It can be understood that the isolation paper is affixed to the second side of the double-sided tape 40 so that the fixed portion 111 of the diaphragm 11 to be tested is located between the double-sided tape 40 and the isolation paper. The fixed portion 111 of the diaphragm 11 to be tested is protected by the isolation paper to prevent the surface of the fixed portion 111 from being subjected to unnecessary friction or indentation during subsequent testing, which may affect the results of the peeling force test.

[0085] Step S215: using a pressing roller to press the side of the release paper away from the fixing portion 111 for multiple times.

[0086] Specifically, in the step S215, the side of the fixing portion 111 away from the double-sided adhesive tape 40 has a release paper, and the release paper can be rolled back and forth smoothly and evenly by a pressure roller in a natural rolling manner, so that the fixing portion 111 can be firmly and evenly attached to the double-sided adhesive tape 40, avoiding excessive pressure on the fixing portion 111, thereby preventing material deformation or stress concentration, and ensuring the stability of the fixed state of the diaphragm 11 to be tested during the test; wherein the pressure roller is in contact with the release paper on the fixing portion 111, and the number of times the pressure roller rolls can be 5 times,

[0087] It can be understood that by using a pressure roller to roll the side of the isolation paper away from the fixed part 111 for multiple times, the adhesion between the diaphragm to be tested 11 and the double-sided tape 40 is made more uniform and stable, ensuring close contact between the double-sided tape 40 and the diaphragm to be tested 11; at the same time, by rolling the side of the isolation paper away from the fixed part 111 for multiple times, bubbles or uneven adhesion that may exist between the contact surface of the double-sided tape 40 and the diaphragm to be tested 11 can be removed, thereby reducing the potential risk of uneven adhesion, thereby avoiding errors in subsequent peeling force test results caused by bubbles or uneven adhesion, and improving overall reliability of use.

[0088] At the same time, when the pressure roller is rolling the diaphragm 11 to be tested, the isolation paper plays a role of buffer protection, avoiding the pressure roller from causing excessive pressure or additional force on the fixing part 111, ensuring that the fixing part 111 maintains its original state, thereby ensuring the accuracy of the subsequent peeling force test results.

[0089] Step S216: removing the release paper to prepare for the subsequent peeling force test.

[0090] Step S30: the free portion 112 is bent along the folding line 113 so that the free portion 112 and the fixed portion 111 are stacked; Figure 5 shown.

[0091] Specifically, in the step S30, the free portion 112 is folded in half along the folding line 113 so that the free portion 112 and the fixed portion 111 are in contact and stacked, wherein at least a portion of the free portion 112 does not overlap with the test plate 30, wherein the free portion 112 is in an operable state (non-fixed state), and the free portion 112 is folded in half along the folding line 113 so that the free portion 112 and the fixed portion 111 are in contact and stacked. At this time, an angle of 180° is formed between the free portion 112 and the fixed portion 111, thereby ensuring that the relative position between the free portion 112 and the fixed portion 111 is accurate, thereby avoiding the situation in which the free portion 112 cannot be accurately clamped by the tensile machine 50 during subsequent testing due to displacement or bending of the free portion 112.

[0092] At the same time, one end of the free portion 112 away from the folding line 113 is located on the outside of the test plate 30, and at least part of the free portion 112 does not overlap with the test plate 30, so that the free portion 112 can be smoothly clamped by the tensile testing machine 50 in subsequent steps without being blocked or restricted by the test plate 30, thereby improving the accuracy of subsequent peeling force test results.

[0093] Step S40 : fixing one end of the free portion 112 away from the folding line 113 to the first fixture 51 , and fixing one end of the test board 30 away from the free portion 112 to the second fixture 52 .

[0094] Specifically, the step S40 includes the following steps:

[0095] Step S41 : providing a tensile testing machine 50 , wherein the tensile testing machine 50 comprises the first clamp 51 and the second clamp 52 .

[0096] Step S42: fix the end of the free portion 112 away from the folding line 113 to the first fixture 51, and fix the end of the test plate 30 away from the free portion 112 to the second fixture 52, and the second fixture 52 is not in contact with the diaphragm 11 to be tested; Figure 6 shown.

[0097] Specifically, in step S42, one end of the free portion 112 away from the folding line 113 is fixed to the first clamp 51, and one end of the test plate 30 away from the free portion 112 is fixed to the second clamp 52, and the second clamp 52 is not in contact with the diaphragm 11 to be tested, thereby ensuring that during the test, the first clamp 51 and the second clamp 52 of the tensile machine 50 clamp the free portion 112 and the test plate 30 respectively, so that the peeling process is more precise; wherein, by arranging the lower clamp not to contact the diaphragm 11 to be tested, the influence of the test plate 30 on the diaphragm 11 to be tested is avoided, and the error caused by the contact friction between the lower clamp and the film to be tested is reduced.

[0098] Step S43: setting the peeling and stretching speed and peeling and stretching distance of the first clamp 51 .

[0099] Specifically, in step S43, the peeling and stretching speed of the first clamp 51 is 50 mm / min, which ensures that the speed of the peeling process is uniform and stable, and avoids inaccurate test data caused by too fast or too slow peeling speed; wherein, too fast peeling speed may lead to an increase in instantaneous impact force, resulting in test data deviation, while too slow speed may cause the tensile machine 50 to respond laggingly, thereby affecting the measurement accuracy.

[0100] The peeling stretching distance is 160 mm. It can be understood that, in this embodiment, the length of the fixed part 111 can be 80 mm, and the length of the free part 112 can be 120 mm. The technical solution of this embodiment is illustrated by an example. By setting the peeling stretching distance to 160 mm, it can be ensured that the bonding part between the diaphragm 11 to be tested and the test plate 30 is fully peeled off, avoiding partial peeling caused by insufficient stretching distance.

[0101] Specifically, the free portion 112 is stretched along the folding line 113 until it is completely peeled off from the test plate 30. Since the length of the free portion 112 is 120 mm and the peeling stretching distance is 160 mm, it can be ensured that during the peeling process, the tensile force of the testing machine is sufficient to cover the fixed portion 111 of the diaphragm 11 to be tested (the portion bonded between the diaphragm 11 to be tested and the test plate 30) and finally completely peel off.

[0102] It should be noted that the present embodiment does not impose any specific restrictions on the length of the free portion 112, the length of the fixed portion 111, and the peeling and stretching distance. It is only necessary to ensure that the diaphragm 11 to be tested can be completely separated from the test plate 30 during the test. In order to better illustrate the innovation of the present embodiment, the present embodiment takes the example that the length of the fixed portion 111 can be 80 mm, the length of the free portion 112 can be 120 mm, and the peeling and stretching distance is 160 mm as an example to illustrate the technical solution of the present embodiment.

[0103] It should be noted that before starting the tensile testing machine 50 , the diaphragm 11 to be tested is kept in a relaxed state to avoid excessive or uneven initial tension of the free portion 112 , which may affect the stress distribution during the stretching process and make the peeling force measurement inaccurate.

[0104] Step S50 : controlling the first clamp 51 to move away from the second clamp 52 so that the fixing portion 111 is peeled off from the test board 30 , and recording the peeling force of the first clamp 51 .

[0105] Specifically, in the step S50 , the peeling stretching speed and the peeling stretching distance of the first clamp 51 are set, the free portion 112 is stretched, the membrane to be tested 11 is peeled off from the test plate 30 , and the peeling force of the first clamp 51 is recorded.

[0106] Among them, the termination force of the first clamp 51 is 50N, which ensures that during the peeling process, once a certain mechanical limit is reached, the tensile testing machine 50 will stop, thereby effectively preventing the peeling force test from exceeding the actual bearing capacity of the diaphragm material and avoiding material damage or unstable test results caused by excessive peeling or stretching.

[0107] The entrance force of the first clamp 51 is 0.1N, which ensures that the tensile testing machine 50 can start the test with a smaller initial force when it is started, avoiding excessively high starting force from generating additional tension on the diaphragm to be tested 11. Through appropriate entrance force, the adhesion interface between the test diaphragm and the test plate 30 can be smoothly peeled off, reducing the initial erroneous data caused by improper entrance force.

[0108] It can be understood that through the steps S10 to S50, the peeling force of the membrane 11 to be tested can be accurately measured, and it can be ensured that each laboratory can operate according to the same process, standardize the test method of the membrane peeling force, reduce the test differences between different laboratories, and improve the consistency of the test results.

[0109] The embodiments of the present application are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. At the same time, for technical personnel in this field, according to the idea of ​​the present application, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for testing the peeling force of a separator, used for testing the peeling strength of a battery separator, characterized in that: include: Provide the diaphragm to be tested; Fixing part of the diaphragm to be tested on the test board, the diaphragm to be tested comprises a fixed part and a free part connected to each other, a fold line is provided between the fixed part and the free part, the fixed part is in contact with the test board, and the free part is separated from the test board; The free portion is bent along the fold line so that the free portion and the fixed portion are stacked; Fixing one end of the free portion away from the folding line to a first fixture, and fixing one end of the test plate away from the free portion to a second fixture; The first clamp is controlled to be away from the second clamp so that the fixing portion is peeled off from the test plate, and the peeling force of the first clamp is recorded.

2. The method for testing the membrane peeling force according to claim 1, characterized in that: The step of fixing part of the diaphragm to be tested on the test board comprises: A double-sided tape is adhered to the surface of the test board, and the diaphragm to be tested is adhered to the surface of the double-sided tape away from the test board, the fixed portion is adhered to the double-sided tape, and the free portion is not in contact with the double-sided tape, wherein the orthographic projection of the fixed portion on the test board is located within the orthographic projection of the double-sided tape on the test board.

3. The method for testing the membrane peeling force according to claim 2, characterized in that: The step of attaching a double-sided tape to the surface of the test board and attaching the diaphragm to be tested to the surface of the double-sided tape away from the test board comprises: Providing a double-sided adhesive tape, the double-sided adhesive tape comprising a first side and a second side arranged opposite to each other, release paper being affixed to the first side and the second side, removing the release paper on the first side of the double-sided adhesive tape, and affixing the first side of the double-sided adhesive tape to the test board; Rolling the second side of the double-sided adhesive tape multiple times using a pressure roller; Removing the release paper on the second surface of the double-sided tape, attaching the fixed portion to the second surface of the double-sided tape, and leaving the free portion out of contact with the double-sided tape; Laminating the release paper to the second surface of the double-sided tape, wherein the fixing portion is located between the double-sided tape and the release paper, and the orthographic projection of the fixing portion on the double-sided tape is located within the orthographic projection of the release paper on the test board; Using a pressing roller to press the side of the release paper away from the fixing portion for multiple times; The release paper is removed.

4. The method for testing the membrane peeling force according to claim 2, characterized in that: The length of the double-sided tape is less than the length of the diaphragm to be tested, and the length of the double-sided tape is greater than or equal to the length of the fixing portion, and the width of the double-sided tape is greater than the width of the diaphragm to be tested.

5. The method for testing the membrane peeling force according to claim 4, characterized in that: The length of the double-sided tape is greater than or equal to 80 mm and less than or equal to 100 mm, and the width of the double-sided tape is 20 mm.

6. The method for testing the peeling force of a separator according to any one of claims 1 to 5, characterized in that: The step of providing a diaphragm to be tested comprises: Fix the diaphragm substrate on the workbench of the diaphragm slitting machine; The membrane slitting machine is controlled to cut the membrane substrate to form a plurality of membrane strips, and at least one membrane strip located in the middle of the plurality of membrane strips is selected as the membrane to be tested.

7. The method for testing the peeling force of a separator according to any one of claims 1 to 5, characterized in that: The length of the free portion is greater than the length of the fixed portion, and at least a portion of the free portion does not overlap with the test board.

8. The method for testing the peeling force of a separator according to any one of claims 1 to 5, characterized in that: The step of fixing the end of the free portion away from the folding line on the first fixture and fixing the end of the test plate away from the free portion on the second fixture comprises: Providing a tensile testing machine, the tensile testing machine comprising the first clamp and the second clamp; Fixing one end of the free portion away from the folding line to the first fixture, and fixing one end of the test plate away from the free portion to the second fixture; The peeling and stretching speed and peeling and stretching distance of the first clamp are set.

9. The method for testing the membrane peeling force according to claim 8, characterized in that: The peeling and stretching speed of the first clamp is 50 mm / min, and the peeling and stretching distance is 160 mm.

10. The method for testing the peeling force of a separator according to any one of claims 1 to 5, characterized in that: In the step of controlling the first clamp to move away from the second clamp to peel the fixing portion from the test plate, and recording the peeling force of the first clamp, the end force of the first clamp is 50N, and the entry force of the first clamp is 0.1N.

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