A material for protecting battery separator stretch clamping and a test method

Abstract

This application relates to a material and testing method for protecting the tensile clamping of a battery separator, comprising an adhesive outer layer, a buffer intermediate layer, and an anti-slip inner layer. The adhesive outer layer has a first region distributed along its width direction and a second region for adhering to the surface of the battery separator. The buffer intermediate layer is adhered to the first region. A portion of the anti-slip inner layer is adhered to the first region, and another portion covers the buffer intermediate layer. The anti-slip inner layer effectively protects the battery separator, and its frictional properties reduce sample slippage during tensile testing, thus ensuring the success rate of the test and the accuracy of the test data. The buffer intermediate layer provides cushioning protection for the battery separator, the anti-slip inner layer, and the adhesive outer layer, preventing stress concentration at the sample clamping end from causing damage and affecting the test results. The adhesive outer layer prevents direct contact between the battery separator and the clamp, thus avoiding debris residue.

Description

Technical Field

[0001] This application relates to the field of material mechanical property testing and characterization technology, and in particular to a material and testing method for protecting the stretching and clamping of a battery separator. Background Technology

[0002] Thin films are typically tested for tensile properties according to GB / T 1040.3-2006. However, the thickness of polyolefin separators for lithium batteries (GB / T 36363-2018) is usually only 16-25 μm. Testing these extremely thin films is difficult and cannot be done effectively. This is because if the film is clamped too loosely, relative slippage can easily occur during the tensile test; conversely, if the film is clamped too tightly, stress concentration will form at the clamp jaws, causing clamping damage. Both of these factors directly affect the success or failure of the test and the accuracy of the test data. Furthermore, excessive clamping can easily leave film debris on the clamp jaws, making cleaning the test fixture difficult and affecting the clamping effect on other test samples. Summary of the Invention

[0003] This application provides a material and testing method for protecting the battery separator during tensile clamping, which can reduce the risk of clamping damage caused by tensile slippage or stress concentration, thereby ensuring the success rate of the test and the accuracy of the test data.

[0004] In a first aspect, a material is provided for protecting the stretching and clamping of a battery separator, comprising:

[0005] An adhesive outer layer having a first region distributed along the width direction of the adhesive outer layer and a second region for bonding to the surface of a battery separator;

[0006] A buffer intermediate layer is attached to the first area;

[0007] The anti-slip inner layer is partially adhered to the first area and partially covers the buffer middle layer.

[0008] In some embodiments, the anti-slip inner layer is partially adhered to the first area along the width direction of the adhesive outer layer, and the other part covers the buffer intermediate layer;

[0009] And / or, one of the long sides of the anti-slip inner layer, the cushioning middle layer, and the adhesive outer layer are aligned;

[0010] In some embodiments, the anti-slip inner layer is made of polyvinylidene chloride film or polyvinyl chloride film.

[0011] In some embodiments, the anti-slip inner layer has a coefficient of friction ≥0.40, longitudinal tensile strength ≥60 MPa, transverse tensile strength ≥80 MPa, longitudinal elongation at break ≥50%, transverse elongation at break ≥540%, and tear resistance ≥0.2 N.

[0012] In some embodiments, the buffer intermediate layer is made of kraft paper or crepe paper.

[0013] In some embodiments, the basis weight of the buffer intermediate layer is approximately 40–120 g / m³. 2 Bursting strength index ≥ 3.3 kpf / m 2 .

[0014] In some embodiments, the adhesive outer layer is a pressure-sensitive self-adhesive label sticker or masking tape;

[0015] And / or, the second zone is provided with release paper.

[0016] Secondly, a method for testing the tensile strength of a battery separator is provided, which includes the following steps:

[0017] Clamping portions are provided at both ends of the battery separator, and the second area of ​​the adhesive outer layer in the clamping portion is attached to the battery separator. One side of the buffer middle layer and the anti-slip inner layer in the clamping portion is attached to the first area of ​​the adhesive outer layer, and the other side is attached to the battery separator. A portion of the anti-slip inner layer covers the buffer middle layer.

[0018] Pressure is applied to the clamping part for pretreatment;

[0019] The device is placed on a testing machine for tensile testing.

[0020] In some embodiments, clamping portions are provided at both ends of the battery separator, including the following steps:

[0021] Provide materials for the protective battery separator stretch clamping as described above;

[0022] Using a pre-defined wrapping method, the material that protects the battery separator is stretched and clamped is wrapped, folded and compacted on the battery separator to form a clamping part on the battery separator;

[0023] Alternatively, clamping portions can be provided at both ends of the battery separator, including the following steps:

[0024] The anti-slip inner layer is folded and compacted around the battery separator using a pre-designed wrapping method.

[0025] The buffer intermediate layer is folded and compacted around the battery separator using a pre-set wrapping method.

[0026] Using a pre-defined wrapping method, the adhesive outer layer is wrapped, folded, and pressed onto the battery separator, and the buffer middle layer and the anti-slip inner layer are attached to the first area of ​​the adhesive outer layer, while the second area of ​​the adhesive outer layer is attached to the surface of the battery separator.

[0027] The first and second zones are distributed along the width of the adhesive outer layer, and a portion of the anti-slip inner layer covers the buffer intermediate layer.

[0028] In some embodiments, the preset embracing method is a U-shaped embracing method, and after folding and compacting, the overlapping part is cut off;

[0029] Alternatively, the preset encircling method can be a U-shaped encircling method.

[0030] The beneficial effects of the technical solution provided in this application include:

[0031] This application provides a material and testing method for protecting the battery separator during tensile clamping. The design of the anti-slip inner layer can effectively protect the battery separator, and the frictional properties of the anti-slip inner layer can reduce the slippage of the tensile sample, thereby ensuring the success rate of the test and the accuracy of the test data.

[0032] The design of the buffer middle layer can buffer and protect the battery separator, the anti-slip inner layer, and the adhesive outer layer. On the one hand, it avoids the adhesive from contacting the stressed parts of the battery separator, thereby avoiding possible unpredictable chemical reactions. On the other hand, it also effectively buffers the stress concentration clamping damage to the battery separator caused by the clamping extrusion, preventing it from breaking from the jaws during testing.

[0033] The adhesive outer layer is designed to secure the buffer middle layer, the anti-slip inner layer, and the battery separator, ensuring ease of operation and preventing debris residue from directly contacting the battery separator with the clamp. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the material for the protective battery separator stretching clamp provided in the embodiments of this application (a second area is provided on the anti-slip inner layer side);

[0036] Figure 2 A schematic diagram of the material for the stretching and clamping of the protective battery separator provided in the embodiments of this application (a second area is provided on the side of the buffer intermediate layer);

[0037] Figure 3 A schematic diagram of the material for the protective battery separator stretching clamping provided in the embodiments of this application (a second zone is provided on both the anti-slip inner layer side and the buffer intermediate layer side);

[0038] Figure 4 A schematic diagram of the material for the stretching and clamping of the protective battery separator provided in the embodiments of this application (a second zone is provided on both sides of the anti-slip inner layer);

[0039] Figure 5 A front view (U-shaped encircling method) showing clamping portions provided at both ends of the battery separator according to an embodiment of this application;

[0040] Figure 6 A top view (U-shaped encircling method) showing clamping portions provided at both ends of the battery separator, as provided in an embodiment of this application;

[0041] Figure 7 A schematic diagram of the U-shaped encircling method provided in the embodiments of this application (the bend of the clamping part is on the long side of the battery separator);

[0042] Figure 8 A schematic diagram of the U-shaped encircling method provided in the embodiments of this application (the bend of the clamping part is on the wide side of the battery separator);

[0043] Figure 9 This is a schematic diagram of the battery separator damage in Comparative Example 1 of this application.

[0044] Figure 10 This is a schematic diagram of the battery separator damage in Embodiment 3 of this application.

[0045] In the diagram: 1. Adhesive outer layer; 10. First zone; 11. Second zone; 2. Buffer middle layer; 3. Anti-slip inner layer; 4. Battery separator. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] See Figure 1As shown, this application provides a material for protecting the stretching and clamping of a battery separator, which includes an adhesive outer layer 1, a buffer intermediate layer 2, and an anti-slip inner layer 3. The adhesive outer layer 1 has a first region 10 distributed along the width direction of the adhesive outer layer 1, and a second region 11 for adhering to the surface of the battery separator 4. The buffer intermediate layer 2 is adhered to the first region 10, and a portion of the anti-slip inner layer 3 is adhered to the first region 10, while another portion covers the buffer intermediate layer 2.

[0048] In this application, an anti-slip inner layer 3 is designed to effectively protect the battery separator, and the friction properties of the anti-slip inner layer 3 can reduce the slippage of the tensile sample, thereby ensuring the success rate of the test and the accuracy of the test data.

[0049] The design of the buffer middle layer 2 can buffer and protect the battery separator 4, the anti-slip inner layer 3 and the adhesive outer layer 1. On the one hand, it avoids the adhesive from contacting the stressed parts of the battery separator 4, thereby avoiding possible unpredictable chemical reactions. On the other hand, it also effectively buffers the stress concentration clamping damage to the battery separator 4 caused by the clamping extrusion, preventing it from breaking from the jaws during the test.

[0050] The adhesive outer layer 1 is designed to fix the buffer middle layer 2, the anti-slip inner layer 3 and the battery separator 4, ensuring the convenience of operation, and using the adhesive outer layer 1 to prevent the battery separator 4 from directly contacting the clamp and causing debris residue.

[0051] The anti-slip inner layer 3 can be attached to the first area 10 along the length of the adhesive outer layer 1, with one part attached and the other part covering the buffer middle layer 2.

[0052] The anti-slip inner layer 3 can also be partially attached to the first area 10 along the width direction of the adhesive outer layer 1, and the other part can cover the buffer intermediate layer 2.

[0053] Given that the material can be manufactured into roll-up products similar to double-sided tape and transparent tape, for ease of production and use, preferably, the anti-slip inner layer 3 is partly pasted onto the first area 10 along the width direction of the adhesive outer layer 1, and the other part covers the buffer intermediate layer 2.

[0054] The function of the second zone 11 is to bond it to the battery separator 4. There are several possible positions for it in the material that protects the battery separator from stretching and clamping.

[0055] For example, as an example, when the other part of the anti-slip inner layer 3 only partially covers the buffer intermediate layer 2 along the width direction of the adhesive outer layer 1, one long side of the anti-slip inner layer 3 is located between the two long sides of the buffer intermediate layer 2. At this time:

[0056] See Figure 1As shown, there is one location in the second zone 11, and the second zone 11 is adjacent to the anti-slip inner layer 3. See also Figure 2 As shown, there is one location in the second region 11, and the second region 11 is adjacent to the buffer intermediate layer 2. See also Figure 3 As shown, there are two second zones 11, one of which is adjacent to the anti-slip inner layer 3, and the other is adjacent to the buffer intermediate layer 2.

[0057] For example, when another part of the anti-slip inner layer 3 completely covers the buffer intermediate layer 2 along the width direction of the adhesive outer layer 1, one long side of the anti-slip inner layer 3 is either aligned with one long side of the buffer intermediate layer 2 or covers one long side of the buffer intermediate layer 2. In this case: see Figure 4 As shown, along the width direction of the adhesive outer layer 1, the second area 11 is provided on at least one side of both sides of the anti-slip inner layer 3.

[0058] Preferably, the buffer intermediate layer 2 is completely covered by the anti-slip inner layer 3 to make full use of the buffer intermediate layer 2.

[0059] Specifically, one long side of the anti-slip inner layer 3 can be aligned with the long sides of both the buffer middle layer 2 and the adhesive outer layer 1.

[0060] It is also possible to align one of the two long sides of the anti-slip inner layer 3 with the long side of the buffer middle layer 2, and the other with the long side of the adhesive outer layer 1.

[0061] The width of the second zone 11 can be determined according to actual testing needs, and is not strictly limited here.

[0062] The material of this application is composed of an adhesive outer layer 1, a buffer intermediate layer 2 and an anti-slip inner layer 3, and a large number of materials for the adhesive outer layer 1, the buffer intermediate layer 2 and the anti-slip inner layer 3 have been screened.

[0063] The anti-slip inner layer 3 can be made of various materials. For example, the anti-slip inner layer 3 can be made of polyvinylidene chloride film or polyvinyl chloride film.

[0064] The anti-slip inner layer 3 has a thickness of 50-70 μm, a width of approximately 30 ± 3 mm, and a length of approximately 20 ± 2 mm.

[0065] The anti-slip inner layer 3 has a coefficient of friction ≥0.40, longitudinal tensile strength ≥60MPa, transverse tensile strength ≥80MPa, longitudinal elongation at break ≥50%, transverse elongation at break ≥540%, and tear resistance ≥0.2N.

[0066] The material of the buffer intermediate layer 2 can be selected from various options. For example, the buffer intermediate layer 2 can be made of kraft paper or crepe paper.

[0067] The buffer intermediate layer 2 is approximately 30±3mm*15±1.5mm in diameter and weighs approximately 40~120g / m². 2 Bursting strength index ≥ 3.3 kpf / m 2 .

[0068] For the adhesive outer layer 1, there are various material options. For example, as an example, the adhesive outer layer 1 can be made of pressure-sensitive self-adhesive label stickers or masking tape.

[0069] Pressure-sensitive self-adhesive labels are approximately 30±3mm*25±1.5mm in size. They are composite materials with paper, film or special materials as the face material, adhesive on the back, and silicone-coated backing paper as the base material. After processing such as die-cutting, they become finished self-adhesive labels.

[0070] For the surface material, a grid bottom mold can be used for papermaking.

[0071] For adhesives, use ordinary strong permanent acrylic latex with initial tack (minimum) of 14.0N and holding power (minimum) of 24.0Hour; PE initial tack (minimum) of 8.0N; minimum labeling temperature of 10℃; minimum service temperature of -20℃; and maximum service temperature of 80℃.

[0072] For the substrate, white transparent glassine paper is usually used. It should be stored away from environments above 50°C or direct sunlight for extended periods. The shelf life is one year at a temperature of 23±2°C and a relative humidity of 50±5%. Products that have exceeded their shelf life can still be used if they pass inspection.

[0073] To prevent the adhesiveness of the second zone 11 from being compromised, release paper is provided on the second zone 11.

[0074] This application also provides a method for testing the tensile strength of a battery separator, which includes the following steps:

[0075] 101: Clamping portions are provided at both ends of the battery separator 4, and the second area 11 of the adhesive outer layer 1 in the clamping portion is attached to the battery separator 4. One side of the buffer intermediate layer 2 and the anti-slip inner layer 3 in the clamping portion is attached to the first area 10 of the adhesive outer layer 1, and the other side is attached to the battery separator 4. A portion of the anti-slip inner layer 3 covers the buffer intermediate layer 2.

[0076] 102: Apply pressure to the clamping part for pretreatment.

[0077] In step 102, the purpose of pre-treating the clamping part is to ensure the adhesion between the clamping part and the battery separator 4.

[0078] When performing pre-treatment by applying pressure, the magnitude of the pressure and the time can be determined according to actual test requirements. For example, as an example, 50 N×1 h can be applied, or 50 N×24 h can be applied.

[0079] 103: Load onto the testing machine for tensile testing, and execute in accordance with the national standards of GB / T 36363-2018 and GB / T 1040.3-2006.

[0080] In the above step 101, there are multiple solutions for setting clamping parts at both ends of the battery separator 4.

[0081] For example, as an example, setting clamping parts at both ends of the battery separator 4 includes the following steps:

[0082] 201: Provide the material for protecting the tensile clamping of the battery separator as described in any of the above embodiments.

[0083] 202: Adopt a preset surrounding method to surround and fold and compact the material for protecting the tensile clamping of the battery separator on the battery separator 4, so as to form a clamping part on the battery separator 4.

[0084] Among them, there are multiple choices for the preset surrounding method. For example, as an example, the preset surrounding method is a square surrounding method, see Figure 5 and Figure 6 shown. At this time, after folding and compacting, it is also necessary to cut off the overlapping part of the material for protecting the tensile clamping of the battery separator. Again, as another example, the preset surrounding method is a U-shaped surrounding method, see Figure 7 and Figure 8 shown, which is a schematic diagram of the wide-side end of the battery separator 4. At this time, the U-shaped surrounding method has two directions. For example, Figure 7 in, the bending part of the clamping part is on the long side of the battery separator 4, while Figure 8 in, the bending part of the clamping part is on the wide side of the battery separator 4.

[0085] Again, as another example, see Figure 5 and Figure 6 shown. Setting clamping parts at both ends of the battery separator 4 includes the following steps:

[0086] 301: Adopt a preset surrounding method to surround and fold and compact the anti-slip inner layer 3 on the battery separator 4.

[0087] 302: Adopt a preset surrounding method to surround and fold and compact the buffer intermediate layer 2 on the battery separator 4.

[0088] 303: Adopt the preset encircling method to encircle and fold and compact the adhesive outer layer 1 on the battery separator 4, and paste the buffer intermediate layer 2 and the anti-slip inner layer 3 on the first area 10 of the adhesive outer layer 1, and paste the second area 11 of the adhesive outer layer 1 on the surface of the battery separator 4; wherein, the first area 10 and the second area 11 are distributed along the width direction of the adhesive outer layer 1, and a part of the anti-slip inner layer 3 covers the buffer intermediate layer 2.

[0089] Similarly, there are multiple choices for the preset encircling method. For example, as an example, the preset encircling method is the square encircling method. Refer to Figure 5 and Figure 6 As shown, at this time, after step 301 is folded and compacted, the overlapping part of the anti-slip inner layer 3 needs to be cut off. After step 302 is folded and compacted, the overlapping part of the buffer intermediate layer 2 needs to be cut off. After step 303 is folded and compacted, the overlapping part of the adhesive outer layer 1 also needs to be cut off. For another example, as another example, the preset encircling method is the U-shaped encircling method. Refer to Figure 7 and Figure 8 As shown, it is a schematic diagram of the wide-side end of the battery separator 4. At this time, the U-shaped encircling method has two directions. For example, Figure 7 In, the bending part of the clamping part is on the long side of the battery separator 4, while Figure 8 In, the bending part of the clamping part is on the wide side of the battery separator 4.

[0090] The difference between the above square encircling method and the U-shaped encircling method is that: the square encircling method needs to cut off the overlapping part, while the U-shaped encircling method does not require this operation.

[0091] The difference between the above two solutions for setting the clamping parts at both ends of the battery separator 4 is that: the former directly uses the finished product of the material for stretching and clamping the protective battery separator, and directly winds the material for stretching and clamping the protective battery separator on the battery separator 4, and cuts off the overlapping part to form the clamping part; while the latter sequentially sets the anti-slip inner layer 3, the buffer intermediate layer 2 and the adhesive outer layer 1 on the battery separator 4, and the overlapping part needs to be cut off at each step; relatively speaking, the former has higher test efficiency.

[0092] The following further elaborates on the present application through specific embodiments.

[0093] In each of the following embodiments, after each embodiment is tested 5 times, the average value is taken.

[0094] Among them, L (longitudinal) and T (transverse) are the longitudinal and transverse directions respectively. Specifically, refer to the transverse and longitudinal representation methods of polyolefin separators for lithium-ion batteries in the standard GB / T36363. Among them, the longitudinal MD in the reference standard is equivalent to L, and the transverse TD is equivalent to T.

[0095] (1) Test the tensile properties of the battery separator for different numbers of layers in the clamping part.

[0096] Table 1

[0097]

[0098] In Comparative Example 1, Example 1, Example 2 and Example 3, the battery separator was made of PE, the thickness of the battery separator was 16um, and the pretreatment was 50N*24h.

[0099] From the test results in Table 1 above, in Example 3, the three-layer structure of this application was used. Whether it was the longitudinal or transverse battery separator, the average tensile strength and average elongation at break were both greater than those of Comparative Example 1, Example 1, and Example 2. This indicates that when testing the battery separator performance, the material used in this application to protect the battery separator during tensile clamping can effectively protect the clamping ends of the battery separator. (See also...) Figure 9 and Figure 10 Without protection, the battery separator shows damage at the clamping area under a microscope. Under the protection of this application, the battery separator shows no damage at the clamping area under a microscope, and stress concentration damage will not occur at the clamping jaws. This indicates that the test results are closer to the true value and the test data are more accurate.

[0100] (2) Test the tensile properties of the battery separator for different pretreatment methods.

[0101] Table 2

[0102]

[0103] In Examples 3, 4, and 5, the battery separator is made of PE, the thickness of the battery separator is 16µm, and the clamping part consists of an anti-slip inner layer, a buffer middle layer, and an adhesive outer layer.

[0104] Based on the data from Example 3 in Table 1 and the test results in Table 2 above, in Example 3, the 50N*24h pretreatment method of this application was used. The average tensile strength and average elongation at break of both the longitudinal and transverse battery separators were greater than those of Examples 4 and 5. This indicates that when conducting battery separator performance tests, the material pretreatment method of this application for protecting the battery separator during tensile clamping can produce a synergistic effect, providing better protection for the battery separator, avoiding damage to the clamping area, and preventing stress concentration at the clamping jaws. The test results are closer to the true values, and the test data are more accurate.

[0105] (3) Test the tensile properties of battery separators for different thicknesses.

[0106] Table 3

[0107]

[0108] In Examples 3, 6, and 7, the battery separator was made of PE, and the clamping part consisted of an anti-slip inner layer, a buffer middle layer, and an adhesive outer layer. The pretreatment was 50N*24h.

[0109] Based on the data from Example 3 in Table 1 and the test results in Table 3 above, in Examples 3, 6, and 7, the average tensile strength and average elongation at break of lithium-ion battery separators of different thicknesses, whether longitudinal or transverse, are all greater than those in Comparative Example 1, Examples 1, 2, 4, and 5. This indicates that when conducting battery separator performance tests, the protective battery separator tension clamping material and pretreatment method of this application can provide protection for battery separators of different thicknesses during tensioning, avoid stress concentration damage at the clamping jaws, and make the test results closer to the true values, resulting in more accurate test data.

[0110] (4) Test the tensile properties of battery separators for different materials.

[0111] Table 4

[0112]

[0113] For each material sample in Table 4, the examples all used an anti-slip inner layer, a buffer middle layer, and an adhesive outer layer for the clamping part. The pretreatment was 50N*24h, and the thickness of the battery separator was 16um. The clamping parts of the comparative examples were not protected. It can be seen that the results are better than those of the unprotected samples in terms of both longitudinal and transverse dimensions and the test results. This indicates that when conducting battery separator performance tests, setting the protective battery separator tensile clamping material and pretreatment method of this application can protect the battery separator of different materials during tensile testing, avoid clamping stress damage at the jaws, and make the test results closer to the true values ​​and the test data more accurate.

[0114] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0115] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0116] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A material for protecting the stretching and clamping of a battery separator, characterized in that, It includes: An adhesive outer layer (1) has a first region (10) distributed along the width direction of the adhesive outer layer (1) and a second region (11) for bonding to the surface of the battery separator (4). A buffer intermediate layer (2) is attached to the first area (10); Anti-slip inner layer (3), part of which is pasted on the first area (10) and the other part is covered on the buffer middle layer (2); The anti-slip inner layer (3) is made of polyvinylidene chloride film or polyvinyl chloride film; The anti-slip inner layer (3) has a friction coefficient ≥0.40, longitudinal tensile strength ≥60Mpa, transverse tensile strength ≥80Mpa, longitudinal elongation at break ≥50%, transverse elongation at break ≥540%, and tear resistance ≥0.2N.

2. The material for protecting the battery separator during stretching and clamping as described in claim 1, characterized in that: The anti-slip inner layer (3) is partly attached to the first area (10) along the width direction of the adhesive outer layer (1), and the other part covers the buffer middle layer (2); And / or, one of the long sides of the anti-slip inner layer (3), the buffer intermediate layer (2) and the adhesive outer layer (1) are aligned.

3. The material for protecting the battery separator during stretching and clamping as described in claim 1, characterized in that: The buffer intermediate layer (2) is made of kraft paper or crepe paper.

4. The material for protecting the battery separator during stretching and clamping as described in claim 3, characterized in that: The weight of the buffer intermediate layer (2) is about 40~120g / m2, and the bursting index is ≥3.3 kpf / m2.

5. The material for protecting the battery separator during stretching and clamping as described in claim 1, characterized in that: The adhesive outer layer (1) is made of pressure-sensitive self-adhesive label stickers or masking tape; And / or, the second zone (11) is provided with release paper.

6. A method for testing the tensile strength of a battery separator, comprising using the material for protecting the battery separator under tensile stress as described in any one of claims 1-5, characterized in that, It includes the following steps: Clamping portions are provided at both ends of the battery separator (4), and the second area (11) of the adhesive outer layer (1) in the clamping portion is attached to the battery separator (4). One side of the buffer intermediate layer (2) and the anti-slip inner layer (3) in the clamping portion is attached to the first area (10) of the adhesive outer layer (1), and the other side is attached to the battery separator (4). A portion of the anti-slip inner layer (3) covers the buffer intermediate layer (2). Pressure is applied to the clamping part for pretreatment; The device is placed on a testing machine for tensile testing.

7. The battery separator tensile testing method as described in claim 6, characterized in that, Clamping portions are provided at both ends of the battery separator (4), including the following steps: Using a pre-set wrapping method, the material that protects the battery separator is stretched and clamped is wrapped, folded and compacted on the battery separator (4) to form a clamping part on the battery separator (4); Alternatively, clamping portions may be provided at both ends of the battery separator (4), including the following steps: Using a pre-set wrapping method, the anti-slip inner layer (3) is wrapped and folded around the battery separator (4) and pressed firmly. The buffer intermediate layer (2) is folded and compacted around the battery separator (4) using a pre-set wrapping method. Using a pre-set wrapping method, the adhesive outer layer (1) is wrapped and folded on the battery separator (4) and the buffer middle layer (2) and the anti-slip inner layer (3) are attached to the first area (10) of the adhesive outer layer (1), and the second area (11) of the adhesive outer layer (1) is attached to the surface of the battery separator (4). The first zone (10) and the second zone (11) are distributed along the width direction of the adhesive outer layer (1), and a portion of the anti-slip inner layer (3) covers the buffer intermediate layer (2).

8. The battery separator tensile testing method as described in claim 7, characterized in that, The preset embracing method is a U-shaped embracing method, and after folding and pressing, the overlapping part is cut off; Alternatively, the preset encircling method can be a U-shaped encircling method.

Images