Dry-method adhesive dispersion consistency evaluation method

Abstract

The invention relates to a dry method binder dispersion consistency evaluation method in the technical field of lithium batteries. The method comprises the following steps: S1, carrying out a stripping test on a to-be-tested sample to obtain a stripping force test value ai; the sample to be detected contains a dry method binder; s2, calculating average peel strength according to the peel strength test value ai; S3, calculating a peel strength standard deviation S and a variable coefficient CV, and judging the dispersion uniformity of the adhesive according to the variable coefficient CV. According to the present invention, the peeling strength test is performed on the to-be-tested sample to obtain the peeling strength curve, the variable coefficient CV value of the fluctuating data on the peeling strength curve is calculated, and the smaller the variable coefficient CV value is, the smaller the dispersion degree of the peeling curve is, such that the better the dispersion consistency of the binder is.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, and in particular to a method for evaluating the dispersion consistency of dry binders. Background Technology

[0002] The binder in lithium-ion batteries acts as a bond between the active materials and other components of the lithium-ion battery electrode, and is a major component supporting the mechanical properties of the positive and negative electrodes. In existing dry-process batteries, the binder is typically fiberized and directly dry-mixed with powders such as active materials, then rolled and shaped to form the dry-process electrode or dry-process electrolyte layer inside the battery. This process eliminates the need for solvents, reducing costs and making it more environmentally friendly compared to wet-process manufacturing. However, uneven mixing of the binder and powder in some dry-process batteries results in uneven binder distribution, which not only affects the bonding between powder components but also the adhesion to substrates such as current collectors, significantly impacting battery performance. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a method for evaluating the dispersion consistency of dry adhesives. This method primarily involves conducting peel strength tests on the test sample to obtain a peel strength curve, and calculating the coefficient of variation (CV) value of the fluctuations on the peel strength curve. A smaller CV value indicates less dispersion of the peel curve, signifying better dispersion consistency of the adhesive. The technical solution of this invention is implemented as follows:

[0004] This invention discloses a method for evaluating the dispersion consistency of dry binders, the method comprising the following steps:

[0005] S1. Perform a peel test on the sample to be tested to obtain the peel force test value a. i The sample to be tested contains a dry binder.

[0006] S2, based on the peel force test value a i Calculate average peel strength

[0007] S3. Calculate the standard deviation of peel strength S and the coefficient of variation CV. Determine the uniformity of adhesive dispersion based on the coefficient of variation CV. The calculation formula is as follows:

[0008]

[0009] Among them, a i The peeling force test value is the peeling force measured within a fixed time interval within the effective peeling length.

[0010] Furthermore, the threshold for the coefficient of variation (CV) is 0.5. When CV < 0.5, the consistency of adhesive dispersion is deemed to meet the standard, and when CV ≥ 0.5, it indicates that the consistency of adhesive dispersion has not met the standard.

[0011] Furthermore, the sample to be tested has a uniform sheet-like structure.

[0012] Furthermore, in step S1, the peel test includes:

[0013] S11. Adhere the test tape to the test plate;

[0014] S12. Adhere one end of the sample to be tested to the tape, and let the other end protrude from the sample to be tested;

[0015] S13. Fix the test plate on the tensile testing machine, bend the extended end of the sample to be tested 180° in the opposite direction and fix it to the clamp, and use the tensile testing machine to pull the sample to be tested off the test tape, and record the peeling force during the peeling process.

[0016] Furthermore, after step S12, the sample to be tested is further subjected to rolling by a test roller.

[0017] Furthermore, in step S13, peeling is performed at a speed of 100±50 mm / min and the peeling force is recorded.

[0018] Furthermore, the adhesive strength of the test tape to the test sample and the test plate is greater than the self-adhesion of the test sample.

[0019] Furthermore, the effective statistical length of the peel on the sample to be tested ranges from 50 mm to 120 mm.

[0020] The advantages of this invention are as follows:

[0021] This invention proposes a method for evaluating the dispersion consistency of dry adhesives, mainly involving peel testing of the sample to be tested. During the peel test, the peel force at different stages of peeling is recorded, i.e., the peel force test value 'a'. i Next, data analysis was performed on several peel force test values, and the coefficient of variation of these peel force test values ​​was calculated. The smaller the coefficient of variation, the smaller the dispersion of the peel force test values ​​and the more concentrated the peel force test values ​​are. This indicates that the peel force did not fluctuate significantly during the peeling process, which in turn indicates that the binder in the test sample is evenly dispersed, thus ensuring the bonding strength between powder particles and the bonding strength between powder particles and substrates such as current collectors. Batteries assembled with electrode structures or electrolyte structures that meet the standards tested by this method have good battery performance.

[0022] Furthermore, this method can not only determine whether the dry binder is uniformly dispersed in the dry electrode or dry electrolyte layer, but also quantify the degree of uniformity. The smaller the calculated degree of variation, the more stable the performance of each region.

[0023] In addition, this application transforms the microscopic dispersion problem into a macroscopically quantifiable mechanical index, taking into account the advantages of practicality and accuracy in detection. Compared with methods such as electron microscopy, it has higher detection efficiency, more accurate evaluation, and is closer to the needs of battery production and use. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the peel test structure in an embodiment of the present invention.

[0026] The meanings of the symbols in the above figures are as follows:

[0027] 1. Test the tape;

[0028] 2. The sample to be tested;

[0029] 3. Test plate. Detailed Implementation

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used in the detailed description is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0032] In the description of specific embodiments of the present invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present invention, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0034] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this invention, the character " / " generally indicates that the preceding and following associated objects have an "or" relationship.

[0035] Throughout this invention, numerical values ​​represent approximate measurements or limits of a range to cover minute deviations from a given value, as well as embodiments with approximately the mentioned value and embodiments with the exact mentioned value. Except for the working examples provided at the end of the detailed description, all numerical values ​​of parameters (e.g., quantities or conditions) in this specification (including the appended claims) should be understood to be modified in all cases by the term “about,” regardless of whether “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows for some minor inaccuracy (approaching the exact value in some way; approximately or reasonably approaching the value; almost). If the inaccuracy provided by “about” is not otherwise understood in this general sense in the art, then “about” as used in this invention at least indicates a variation that can be produced by common methods of measuring and using such a parameter. For example, “about” may include a variation less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in some respects, optionally less than or equal to 0.1%.

[0036] Additionally, the disclosure of the range includes the disclosure of all values ​​across the entire range and the disclosure of further subdivided ranges, including the endpoints and subranges given for these ranges.

[0037] In existing dry-process batteries, dry binders are typically fiberized and mixed with powder, allowing the powder to be bonded together by the dry binder to form a dry electrode or dry electrolyte layer. However, uneven mixing of the powder and dry binder leads to uneven distribution of the binder in the dry electrode or dry electrolyte layer, affecting not only the bonding between powder particles but also the bonding strength with pre-fabricated composite substrates such as current collectors, significantly impacting battery performance. To address these issues, this invention proposes a technical solution that involves performing peel strength tests on the test sample to obtain a peel strength curve. The coefficient of variation (CV) of the fluctuating data on the peel strength curve is then calculated. A smaller CV value indicates less dispersion in the peel curve, signifying better uniformity of binder dispersion.

[0038] The test samples applicable to this invention can be either dry-process electrodes or dry-process electrolyte membranes. Specifically, the dry-process electrode is formed by mixing a fibrous binder (dry-process binder) with positive electrode active material particles and then extruding the mixture into a sheet; the dry-process electrolyte membrane is formed by mixing a fibrous binder with electrolyte particles and then extruding the mixture into a sheet. Specifically, the active material and electrolyte material can be materials commonly used in dry-process batteries, and no further restrictions are imposed. The type of dry-process binder is a commonly used fibrous binder in the prior art, and this invention does not impose any restrictions on this.

[0039] The technical solution of the present invention will now be described in detail.

[0040] A method for evaluating the dispersion consistency of dry binders includes the following steps:

[0041] S1. Perform a peel test on the sample to be tested to obtain the peel force test value a. i The sample to be tested contains a dry binder.

[0042] The aforementioned dry adhesive is specifically an adhesive capable of fibrosis. When preparing the sample to be tested, the dry adhesive is mixed into the material without adding solvent. Through high-speed stirring, the adhesive is fibrousized to achieve material bonding.

[0043] For example, the fiberizable adhesive may include, but is not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), cellulose, nanocellulose, nanofibers (CNF), polyaniline (PANI), polypyrrole (PPy), polyrotaxane, etc., or any combination thereof.

[0044] The aforementioned test samples also include battery material powder, which can be any one of positive electrode active material, negative electrode active material, or solid electrolyte. The test samples are prepared by mixing battery material and dry binder and stirring at high speed to form a slurry. The slurry is then coated onto a release film. After the slurry solidifies and dries, a self-supporting film is formed. The self-supporting film is then removed from the release film to obtain the test sample.

[0045] In some embodiments, the positive electrode active material includes a compound that can reversibly insert and deintercalate lithium ions.

[0046] In some embodiments, the positive electrode active material comprises one or more transition metal cations, such as manganese (Mn), nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), vanadium (V), and combinations thereof.

[0047] In some embodiments, the positive electrode active material is one of layered oxides, spinel, and polyanion.

[0048] In some embodiments, the specific type of negative electrode active material is not specifically limited and can be selected according to requirements. Specifically, the negative electrode active material is selected from one or more of the following: natural graphite, artificial graphite, mesophase microcarbon spheres (MCMB), hard carbon, soft carbon, silicon, silicon-carbon composites, Li-Sn alloys, Li-Sn-O alloys, Sn, SnO, SnO2, spinel-structured lithiated TiO2-Li4Ti5O12, and Li-Al alloys. Non-limiting examples of carbon materials include crystalline carbon, amorphous carbon, and mixtures thereof. Crystalline carbon can be amorphous or flake-shaped, small flake-shaped, spherical, or fibrous natural or artificial graphite. Amorphous carbon can be soft carbon, hard carbon, mesophase pitch carbides, calcined coke, etc.

[0049] In some embodiments, the solid electrolyte includes one or more of oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, hydride solid electrolytes, boride solid electrolytes, and nitride solid electrolytes.

[0050] In some embodiments, the test sample is a uniform sheet structure. Specifically, the test sample has uniform width, length, and thickness. If the width, length, and thickness of the test sample are not uniform, the narrower parts are more prone to breakage during the pulling process, affecting the peel test value and thus affecting the judgment of the dispersion consistency of the dry adhesive.

[0051] The peel test described above is an experiment that measures the degree of adhesion of the test sample by applying a force in a specific direction to the test sample. Its core purpose is to evaluate the adhesion strength of the test sample.

[0052] In some specific embodiments, the above-mentioned peel test is performed using methods such as... Figure 1 The peeling device shown includes the following steps:

[0053] S11. Adhere the test tape 1 onto the test plate 3;

[0054] S12. Adhere one end of the sample to be tested 2 to the test tape 1, and let the other end protrude from the test tape 1;

[0055] S13. Fix the test plate 3 on the tensile testing machine. Bend the sample 2 to be tested 180° in the opposite direction from the end of the test tape 1 and fix it to the clamp. Use the tensile testing machine to pull the sample 2 to be tested off the tape and peel it off. Record the peeling force during the peeling process.

[0056] The test tape 1 in step S11 above is specifically a double-sided adhesive tape. One side of the test tape 1 is attached to the test plate 3, and the other side of the test tape 1 is used to adhere to the sample 2 to be tested. It has good adhesion, temperature resistance and stability, and can meet the basic requirements of the standard for test adhesive tape, thereby ensuring the accuracy and reliability of the peel strength test results.

[0057] Furthermore, the adhesion of the test tape 1 to the test sample 2 and the test plate 3 is much greater than the self-adhesion of the test sample 2. With this setup, when peeling off the test sample 2, the test sample 2 is peeled into two parts along the thickness direction, so that one part of the test sample 2 along the thickness direction remains on the test tape 1, while the other part is pulled up by the clamp, which can test the adhesion effect between the powder particles inside the test sample 2.

[0058] Step S12 specifically involves adhering one end of the sample 2 to be tested to the test tape 1, i.e., to the test plate 3, while the other end extends beyond the test tape 1. The width of the sample 2 is the same as the width of the test tape 1, and the sample 2 and the test tape 1 completely overlap in the width direction. This ensures effective adhesion of the sample 2 and helps maintain balanced force in the width direction when the sample is pulled, thus improving the test results. Specifically, the width range of the sample 2 and the test tape 1 is 24±0.5mm, and the length of the sample 2 adhered to the test tape 1 is 300±5mm.

[0059] Furthermore, after the sample 2 to be tested is adhered to the test tape 1, the sample 2 is rolled and pressed by a test roller. The test roller rolls back and forth on the test tape 1 three times at a speed of 300 mm / min to ensure the adhesion between the sample 2 and the test tape 1. The test roller consists of a cylindrical steel pressure roller and a rubber layer covering the surface of the steel pressure roller. The rubber layer protects the surface of the sample 2 during rolling, preventing scratches on the surface of the sample 2 and affecting the test results.

[0060] Furthermore, the steel pressure roller has a diameter of 85±2.5mm. Within this diameter range, the steel pressure roller has a suitable contact arc length with the sample 2 under test, allowing the sample 2 to withstand appropriate high pressure for a suitable duration during contact, which helps ensure the bonding quality between the sample 2 and the test tape 1. Additionally, the width of 45±1.5mm allows the steel pressure roller to completely cover both the sample 2 and the test tape 1 in the width direction, ensuring uniform adhesion between them. Moreover, the roller's pressing direction is parallel to the peeling direction of the sample 2, i.e., the length direction of the sample 2, ensuring uniform bonding strength between the sample 2 and the test tape 1 throughout the width direction, reducing the impact of uneven contact surfaces in the width direction on the peeling force test. Finally, the rubber layer thickness is 6mm to prevent damage to the sample 2.

[0061] Furthermore, when performing the peel test on sample 2, the test temperature was controlled at 23±2℃ and the humidity was controlled at 50±5%RH to avoid the influence of temperature and humidity changes on the adhesive performance and thus data deviation.

[0062] In step S13 above, specifically, after pressing with the test roller, the test plate 3 is fixed on the tensile testing machine, and the end of the sample to be tested 2 extending from the tape is bent 180° in the opposite direction and clamped in the clamp of the tensile testing machine. The sample to be tested 2 is pulled in the opposite direction to achieve 180° peeling of the sample to be tested 2. During the peeling process, the magnitude of multiple peeling forces is recorded, and thus the peel strength curve can be obtained.

[0063] Furthermore, in the peel test, the clamp continuously peels the sample 2 at a speed of 100±50 mm / min. It should be noted that the tensile testing machine is a common device in the art, capable of measuring the tensile force in real time during the peeling process. Therefore, no schematic diagram is provided in this embodiment, which does not affect those skilled in the art from implementing the technical solutions described in this invention.

[0064] Furthermore, during the peeling process, the current peeling force is recorded at preset intervals, and the peeling force measured at the i-th time is the peeling force test value a. i This leads to several stripping test values, where i represents the collection order, i = 1, 2, 3, 4, ... n.

[0065] S2, based on the peel force test value a i Calculate average peel strength

[0066] Specifically, several peel force test values ​​a i The average peel strength can be obtained by adding the results together and dividing by the total number of results.

[0067] Furthermore, the effective statistical length of the peel on sample 2 ranges from 50mm to 120mm. Due to various factors affecting the initial and final stages of peeling, the peel force test results are inaccurate, and fluctuations in these stages impact the overall peel force test. Therefore, after starting the tensile testing machine, the initial and final stages were found to be outside the statistical range. The effective statistical length of the peel force test value for sample 2 is defined as the middle stage of peeling, ranging from 50mm to 120mm. Within this effective statistical length, one peel force test value 'a' is recorded per second. i In step S2, the peel force test value a is obtained based on the effective statistical length. i (a1, a2, a3, a4,,,,a n The average peel strength is calculated. The peel force test value 'a' obtained within this effective length range is... i It can reduce the impact of interfering data during data analysis, thereby improving the accuracy of the evaluation of the dispersion consistency of dry binders.

[0068] Specifically, the total peel length of the sample 2 to be tested is H, the initial peel length at the beginning of the peeling process is H1, the final peel length at the end of the peeling process is H2, and the effective peel length in the middle stage is H3, where H = H1 + H2 + H3; and 5 mm > H1 > 15 mm, H2 > 5 mm. Having the initial peel length and the final peel length within the corresponding length range improves the validity of the measurement data and reduces the impact of noise data on the accuracy of the dry adhesive dispersion consistency evaluation.

[0069] S3. Calculate the standard deviation of peel strength S and the coefficient of variation CV. Determine the uniformity of adhesive dispersion based on the coefficient of variation CV. The calculation formula is as follows:

[0070]

[0071] Among them, a i The peeling force test value is the peeling force measured within a fixed time interval within the effective peeling length.

[0072] Specifically, the smaller the calculated coefficient of variation, the stronger the peel force test value a. i The more concentrated the data, the more uniformly the adhesive is dispersed.

[0073] Furthermore, the threshold for the coefficient of variation (CV) is 0.5. When CV < 0.5, the adhesive dispersion consistency is considered to be up to standard, and when CV ≥ 0.5, the adhesive dispersion consistency is considered to be down to standard.

[0074] Specifically, if the adhesive is uniformly dispersed, the bond strength is consistent throughout the test sample, and the peel force will not vary significantly across different areas. The resulting peel strength curve will be relatively flat with minimal fluctuations. Conversely, if the adhesive is unevenly dispersed, areas with less adhesive will have weaker adhesion, leading to fluctuations in peel force at those locations. Areas with more adhesive will have stronger adhesion, also resulting in fluctuations in peel force at those locations, thus affecting the dispersion of the peel force. Therefore, by calculating the coefficient of variation of the peel force and determining the dispersion of the peel strength curve, the uniformity of the adhesive dispersion can be assessed.

[0075] In this application, a peel test is performed on the sample to be tested, and the peel force at different stages of peeling is recorded during the peel test, i.e., the peel force test value a. i Next, data analysis was performed on several peel force test values ​​to calculate the coefficient of variation. Based on the coefficient of variation, the uniformity of the binder dispersion in the dry electrode or dry electrolyte layer was determined. This, in turn, assessed the adhesion of the powder within the dry electrode or dry electrolyte layer, as well as the adhesion strength between the dry electrode or dry electrolyte layer and the substrate film such as the current collector. Dry electrodes or dry electrolyte layers assessed in this way, when used in batteries, help ensure battery quality and performance.

[0076] Furthermore, this method can not only determine whether the dry binder is uniformly dispersed in the dry electrode or dry electrolyte layer, but also quantify the degree of uniformity. The smaller the calculated degree of variation, the more stable the performance of each region.

[0077] In addition, this application transforms the microscopic dispersion problem into a macroscopically quantifiable mechanical index, taking into account the advantages of practicality and accuracy in detection. Compared with methods such as electron microscopy, it has higher detection efficiency, more accurate evaluation, and is closer to the needs of battery production and use.

[0078] In some embodiments, the sample to be tested is prepared by sampling a mixed slurry.

[0079] Specifically, the mixed slurry is the slurry formed during the battery manufacturing process by mixing battery material powder and dry binder in a mixer. Samples of the slurry to be tested are taken from different locations within the mixer. Several samples are coated onto a release film, and after the slurry sets and dries, a self-supporting film is formed. The self-supporting film is then removed from the release film, resulting in multiple test samples. Peel tests are performed on these multiple samples to obtain peel test values, and the corresponding coefficients of variation are calculated. The different coefficients of variation are then compared. If the difference is small, it indicates that the dry binder in the mixed slurry is evenly dispersed. If the difference is too large, further mixing of the battery material powder and dry binder is required. This method allows for the assessment of the uniformity of slurry mixing during the mixing stage containing dry binder.

[0080] In some embodiments, the sample to be tested is prepared by sampling a prepared dry electrode or dry electrolyte.

[0081] Specifically, the prepared dry electrode or dry electrolyte layer refers to the dry electrode or dry electrolyte layer that is batch-prepared during the production process. Test samples of the appropriate size can be cut from different dry electrode or dry electrolyte layers within the same batch, and peel tests can be performed on multiple test samples. The coefficient of variation is calculated, and then the multiple coefficients of variation are compared. If the differences between the multiple coefficients of variation are small, it indicates that the dispersion consistency of the dry binder in the batch of dry electrode or dry electrolyte is good; if the differences between the multiple coefficients of variation are too large, it indicates that the dispersion consistency of the dry binder in the batch of dry electrode or dry electrolyte is poor.

[0082] In some embodiments, multiple test samples can be cut from the same dry electrode or dry electrolyte layer, and peel tests can be performed on the multiple test samples. The coefficient of variation is calculated, and by comparing the differences between the multiple coefficients of variation, it can be determined whether the dry binder dispersion on the entire dry electrode or dry electrolyte layer is consistent. The smaller the difference, the better the dispersion consistency; the larger the difference, the poor the dispersion consistency.

[0083] This application provides only one method for determining the dispersion consistency of dry binder in slurry, prepared dry electrode, or dry electrolyte layer based on the comparison of peel force dispersion coefficient. The specific value of the difference in peel force dispersion coefficient is not limited, and the specific judgment can be determined according to actual production requirements.

[0084] It should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the dispersion uniformity of a dry binder, characterized by, The method comprises the following steps: S1, performing a peeling test on the sample to be tested to obtain a peeling force test value a i ; the sample to be tested contains a dry binder; S2, according to the peeling force test value a i The average peeling strength was calculated S3, calculating the peeling strength standard deviation S and the coefficient of variation CV, judging the adhesive dispersion uniformity according to the coefficient of variation CV, and the calculation formula is: wherein a i is the peel force detection value for the fixed time interval within the effective peel length.

2. The method for evaluating the dispersion uniformity of a dry binder according to claim 1, characterized by, The determination threshold of the coefficient of variation CV is 0.5, when CV < 0.5, it is determined that the adhesive dispersion consistency meets the standard, and when CV ≥ 0.5, it is indicated that the adhesive dispersion consistency does not meet the standard.

3. The method for evaluating the dispersion uniformity of a dry binder according to claim 1, characterized by, The sample to be tested is in a uniform sheet structure.

4. The method for evaluating the consistency of dry binder dispersion according to claim 1, characterized by, In the S1 step, the peeling test comprises: S11, adhering the test tape on the test plate; S12, adhering one end of the sample to be tested to the tape, and the other end extending from the sample to be tested; S13, fixing the test plate on the tensile testing machine, reversely bending the sample to be tested by 180° and fixing it on the chuck, and peeling the sample to be tested from the test tape by the tensile testing machine, and recording the peeling force during the peeling process.

5. The method for evaluating the consistency of dry binder dispersion according to claim 4, characterized in that, After the step S12, it further comprises rolling the sample to be tested by the test roller.

6. The method for evaluating the consistency of dry binder dispersion according to claim 4, characterized by, In the step S13, the peeling is performed at a speed of 100 ± 50 mm / min, and the peeling force is recorded.

7. The method for evaluating the consistency of dry binder dispersion according to claim 4, characterized by, The adhesion of the test tape to the sample to be tested and the test plate is greater than the self-adhesion of the sample to be tested.

8. The method of claim 1, wherein the method is a method of evaluating the uniformity of dry binder dispersion, characterized by, The effective statistical length of the sample to be tested is 50 mm to 120 mm.

9. The method for evaluating the consistency of dry binder dispersion according to claim 8, wherein The total peeling length is H, the initial peeling length is H1, the end peeling length is H2, and the effective peeling length is H3, H = H1 + H2 + H3; wherein, 5 mm > H1 > 15 mm, and H2 > 5 mm.

10. The method of claim 1, wherein the method is a method of evaluating the consistency of a dry binder dispersion, and Step S1 includes, in the peeling test, recording one peeling force detection value a per second i .

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