A method for detecting diaphragm compression rate

Abstract

The present invention discloses a diaphragm compression rate detection method, which relates to the technical field of lithium batteries. A diaphragm compression rate detection method of the present invention comprises: providing a first unit to be tested, the first unit to be tested comprises a positive electrode sheet to be tested and a first diaphragm attached to both sides of the positive electrode sheet to be tested; measuring the thickness of the first unit to be tested and the positive electrode sheet to be tested, and obtaining the thickness of the first diaphragm; providing a second unit to be tested, the second unit to be tested comprises a target positive electrode sheet and a second diaphragm attached to both sides of the target positive electrode sheet; measuring the thickness of the target positive electrode sheet and the second diaphragm; performing hot pressing treatment on the first unit to be tested and the second unit to be tested, and measuring the thickness of the first unit to be tested, the target positive electrode sheet and the second diaphragm after hot pressing. Through the diaphragm compression rate detection method provided by the present invention, the changes of the diaphragm before and after hot pressing can be accurately reflected.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a method for detecting a diaphragm compression rate. Background Art

[0002] In the production and manufacturing of batteries, the glue-coated diaphragm plays an important role. The glue-coated diaphragm is hot-pressed at a preset pressure and temperature to adhere the glue to the surface of the pole piece, thereby shaping the battery cell and preventing the core package from changing its core and internal wrinkles. During the hot pressing process, the thickness of the diaphragm will change to a certain extent, and the glue layer will also change, so the specific change in the diaphragm cannot be well confirmed and quantified. At this time, if the thickness change is confirmed only by measuring the difference in thickness of the diaphragm before and after hot pressing, there will be errors. At the same time, when the diaphragm is removed from the pole piece, the active material will be bonded to the diaphragm, and the ceramic layer and the glue layer will also be bonded to the pole piece, making the data not referenceable and accurate during actual sampling and measurement. Summary of the invention

[0003] The object of the present invention is to provide a method for detecting the compression rate of a diaphragm, which can reflect the changes of the diaphragm before and after hot pressing through a simple and intuitive measuring method.

[0004] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0005] The present invention provides a method for detecting a diaphragm compression rate, which comprises:

[0006] Providing a first unit to be tested, the first unit to be tested comprising a positive electrode sheet to be tested and a first diaphragm attached to two sides of the positive electrode sheet to be tested;

[0007] Measuring the thickness of the first unit to be tested and the positive electrode sheet to be tested to obtain the thickness of the first diaphragm;

[0008] Providing a second unit to be tested, the second unit to be tested comprising a target positive electrode sheet and a second diaphragm attached to two sides of the target positive electrode sheet;

[0009] Measuring the thickness of the target positive electrode sheet and the second separator;

[0010] Performing hot pressing treatment on the first unit to be tested and the second unit to be tested, and measuring the thickness of the first unit to be tested, the target positive electrode sheet, and the second separator after hot pressing;

[0011] Obtaining the thickness of the first diaphragm after hot pressing according to the thickness of the positive electrode sheet to be tested, the thickness of the first unit to be tested after hot pressing, and the difference in thickness of the target positive electrode sheet before and after hot pressing; and

[0012] The diaphragm compression rate is obtained according to the thickness of the first diaphragm and the thickness of the first diaphragm after hot pressing.

[0013] In one embodiment of the present invention, the first diaphragm is a single-sided adhesive-coated diaphragm, and the adhesive layer of the single-sided adhesive-coated diaphragm is bonded to the positive electrode sheet to be tested.

[0014] In one embodiment of the present invention, the compression rate of the positive electrode sheet is obtained by the thickness difference of the target positive electrode sheet before and after hot pressing.

[0015] In one embodiment of the present invention, the thickness of the positive electrode sheet to be tested after hot pressing is obtained according to the thickness of the positive electrode sheet to be tested and the compression rate of the positive electrode sheet.

[0016] In one embodiment of the present invention, the first diaphragm is a double-sided adhesive-coated diaphragm, and the adhesive layer on one side of the double-sided adhesive-coated diaphragm is bonded to the positive electrode sheet to be tested, and the adhesive layer on the other side is bonded to the non-adhesive-coated diaphragm.

[0017] In one embodiment of the present invention, obtaining the thickness of the first diaphragm after hot pressing comprises the following steps:

[0018] measuring the thickness of the non-adhesive diaphragm;

[0019] Obtaining a compression rate of the second diaphragm according to the thickness of the second diaphragm and the thickness of the second diaphragm after hot pressing;

[0020] According to the thickness of the non-glue-coated diaphragm and the compression rate of the second diaphragm, the thickness of the non-glue-coated diaphragm after hot pressing is obtained;

[0021] Obtaining the thickness of the positive electrode sheet to be tested after hot pressing according to the difference between the thickness of the positive electrode sheet to be tested and the thickness of the target positive electrode sheet before and after hot pressing; and

[0022] The thickness of the first diaphragm after hot pressing is obtained through the thickness of the unit to be tested after hot pressing, the thickness of the positive electrode sheet to be tested after hot pressing and the thickness of the non-glue-coated diaphragm after hot pressing.

[0023] In one embodiment of the present invention, the compression rate of the separator is obtained according to the thickness of the positive electrode sheet to be tested, the thickness of the first separator and the thickness of the first separator after hot pressing.

[0024] In one embodiment of the present invention, the diaphragm compression rate detection device comprises:

[0025] The first unit to be tested comprises a positive electrode sheet to be tested and a first diaphragm attached to two sides of the positive electrode sheet to be tested;

[0026] The second unit to be tested includes a target positive electrode sheet and a second diaphragm attached to two sides of the target positive electrode sheet;

[0027] an acquisition module, through which the first unit under test and the second unit under test are provided;

[0028] A compression module, through which the first unit under test and the second unit under test are subjected to heat compression treatment;

[0029] A measuring module, used to measure the thickness of the first unit to be tested and the positive electrode sheet to be tested, and obtain the thickness of the first diaphragm; measure the thickness of the target positive electrode sheet and the second diaphragm before and after hot pressing; measure the thickness of the first unit to be tested, the target positive electrode sheet and the second diaphragm after hot pressing; and

[0030] A processing module is provided to calculate the compression rate of the diaphragm according to the processing module.

[0031] In one embodiment of the present invention, the compression module sets the same heat pressing parameters during each heat pressing.

[0032] In one embodiment of the present invention, the measuring module adopts a laser thickness gauge.

[0033] As described above, the present invention provides a diaphragm compression rate detection method, providing a first unit to be tested and a second unit to be tested, and through a simple and feasible operation method, effectively and intuitively measuring the thickness of the pole piece and the diaphragm before and after hot pressing. And through this thickness value, the compression rate of the diaphragm is calculated according to the calculation formula, so as to accurately reflect the changes of the diaphragm before and after hot pressing. At the same time, the compression rate of the diaphragm can also be used to judge whether the hot pressing state of the battery cell meets the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a flow chart of a diaphragm compression rate detection method;

[0036] Figure 2 This is a schematic diagram of the first unit under test before hot pressing;

[0037] Figure 3 This is a schematic diagram of the first unit under test after hot pressing;

[0038] Figure 4 This is a schematic diagram of the second unit under test before hot pressing;

[0039] Figure 5 This is a schematic diagram of the second unit under test after hot pressing;

[0040] Figure 6is another schematic diagram of a first unit under test before hot pressing;

[0041] Figure 7 is a schematic diagram of another first unit under test after hot pressing;

[0042] Figure 8 It is a schematic diagram of the structure of a diaphragm compression rate detection system;

[0043] Fig. 9 The figure is a schematic diagram of the structure of a diaphragm compression rate detection device.

[0044] Component number description

[0045] 100-first unit to be tested; 101-positive electrode sheet to be tested; 102-first diaphragm; 103-non-adhesive diaphragm; 1020-first adhesive layer; 1021-second adhesive layer; 200-second unit to be tested; 201-target positive electrode sheet; 202-second diaphragm; 301-measuring unit; 302-compression unit; 303-unit to be compressed; 304-processing unit; 400-diaphragm compression rate detection device; 401-acquisition module; 402-measuring module; 403-compression module; 404-processing module. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings attached to this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which this solution can be implemented, so they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in this solution without affecting the efficacy and purpose that can be achieved by this solution.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0049] At present, lithium-ion batteries are widely used in electric vehicles, mobile phones, computers and other equipment. In the production and manufacturing of lithium batteries, it is usually necessary to use a glue-coated diaphragm, which is used to shape the battery cell by hot pressing the diaphragm. During the hot pressing process, the thickness of the diaphragm will change, and the amount of change is not easy to measure accurately. At the same time, the glue layer bonded between the diaphragm and the pole piece affects the measurement result. This embodiment provides a diaphragm compression rate detection method, which can accurately measure the compression rate of the diaphragm after hot pressing the diaphragm, so as to reflect the changes of the diaphragm before and after hot pressing.

[0050] See also Figure 1 As shown, in one embodiment of the present invention, the diaphragm compression rate detection method mainly includes the following steps S10 to S16.

[0051] Step S10, providing a first unit to be tested, wherein the first unit to be tested comprises a positive electrode sheet to be tested and a first diaphragm attached to two sides of the positive electrode sheet to be tested.

[0052] Step S11, measuring the thickness of the first unit to be tested and the positive electrode sheet to be tested, and obtaining the thickness of the first diaphragm.

[0053] Step S12, providing a second unit to be tested, wherein the second unit to be tested includes a target positive electrode sheet and a second separator attached to two sides of the target positive electrode sheet.

[0054] Step S13, measuring the thickness of the target positive electrode sheet and the second separator.

[0055] Step S14, performing hot pressing treatment on the first unit under test and the second unit under test, and measuring the thickness of the first unit under test, the target positive electrode sheet and the second separator after hot pressing.

[0056] Step S15, obtaining the thickness of the first separator after hot pressing according to the thickness of the positive electrode sheet to be tested, the thickness of the first unit to be tested after hot pressing, and the change in the target positive electrode sheet thickness.

[0057] Step S16: Obtain the compression rate of the diaphragm according to the thickness of the first diaphragm and the thickness of the first diaphragm after hot pressing.

[0058] See also Figure 2As shown, in one embodiment of the present invention, the first unit to be tested 100 includes a positive electrode sheet to be tested 101 and a first diaphragm 102, and the first diaphragm 102 is attached to both sides of the positive electrode sheet to be tested 101. In this embodiment, the first diaphragm 102 can be set as, for example, a single-sided glue-coated diaphragm, and the single-sided glue-coated diaphragm is glued by roller coating and spraying. In other embodiments, the first diaphragm 102 can also be set as, for example, a ceramic diaphragm. The first diaphragm 102 is coated with a first glue layer 1020, and the first glue layer 1020 is attached to both sides of the positive electrode sheet to be tested 101. At this time, the thickness of the first unit to be tested 100 and the thickness of the positive electrode sheet to be tested 101 are measured.

[0059] See also Figure 3 As shown, in one embodiment of the present invention, the first unit to be tested 100 is subjected to hot pressing. When hot pressing is performed at a preset pressure and temperature, the thickness of the positive electrode sheet 101 to be tested and the first diaphragm 102 will change. At the same time, during the hot pressing process, the first adhesive layer 1020 between the positive electrode sheet 101 to be tested and the first diaphragm 102 changes, and the adhesive of the first adhesive layer 1020 is bonded to the positive electrode sheet 101 to be tested, so the thickness of the positive electrode sheet 101 to be tested and the first diaphragm 102 after hot pressing cannot be measured separately. At this time, the thickness of the first unit to be tested 100 can be measured.

[0060] See also Figure 4 As shown, in one embodiment of the present invention, the second unit under test 200 includes a target positive electrode sheet 201 and a second diaphragm 202, and the second diaphragm 202 is attached to both sides of the target positive electrode sheet 201. In this embodiment, the second diaphragm 202 is provided as, for example, a non-adhesive diaphragm, attached to the target positive electrode sheet 201, and there is no adhesive coating layer between the target positive electrode sheet 201 and the second diaphragm 202. At this time, the thickness of the target positive electrode sheet 201 and the thickness of the second diaphragm 202 are measured.

[0061] See also Figure 5 As shown, in one embodiment of the present invention, the second unit under test 200 is subjected to hot pressing. When hot pressing is performed at a preset pressure and temperature, the thickness of the target positive electrode sheet 201 and the second diaphragm 202 will change. Because there is no adhesive layer between the target positive electrode sheet 201 and the second diaphragm 202, at this time, the target positive electrode sheet 201 and the second diaphragm 202 can be measured separately to obtain the thickness of the target positive electrode sheet 201 after hot pressing and the thickness of the second diaphragm 202 after hot pressing.

[0062] See also Figures 4 to 5As shown, in one embodiment of the present invention, the thickness of the target positive electrode sheet 201 changes through hot pressing, and the compression rate of the target positive electrode sheet 201 is calculated. Specifically, the compression rate T1 of the positive electrode sheet can be obtained by the following formula: T1 = (h4-h6) / h4. Among them, h4 is the thickness of the target positive electrode sheet 201 before hot pressing, and h6 is the thickness of the target positive electrode sheet 201 after hot pressing.

[0063] See also Figures 2 to 3 As shown, in one embodiment of the present invention, after the first diaphragm 102 is subjected to hot pressing, the first adhesive layer 1020 is bonded to the positive electrode sheet 101 to be tested, so the thickness of the positive electrode sheet 101 to be tested and the first diaphragm 102 after hot pressing cannot be directly measured. Specifically, the thickness H1 of the first diaphragm 102 after hot pressing can be obtained by the following formula: H1 = h3-h2×(1-T1). Among them, h2 is the thickness of the positive electrode sheet 101 to be tested, h3 is the thickness of the first unit 100 to be tested after hot pressing, and T1 is the compression rate of the positive electrode sheet.

[0064] See also Figure 2 As shown, in one embodiment of the present invention, the compression rate W1 of the first diaphragm can be obtained by the following formula: W1=1-H1 / (h1-h2). Wherein, H1 is the thickness of the first diaphragm 102 after hot pressing, h1 is the thickness of the first unit to be tested 100, and h2 is the thickness of the positive electrode sheet 101 to be tested.

[0065] See also Figure 6 As shown, in one embodiment of the present invention, the first diaphragm 102 can also be provided with, for example, a double-sided adhesive diaphragm, and the double-sided adhesive diaphragm is also coated with adhesive by roller coating and spraying. The first diaphragm 102 is coated with a first adhesive layer 1020 and a second adhesive layer 1021. The first adhesive layer 1020 is attached to both sides of the positive electrode sheet 101 to be tested, and is bonded to the positive electrode sheet 101 to be tested, and the second adhesive layer 1021 is adhered to the non-adhesive diaphragm 103. At this time, the first unit to be tested 100 includes the positive electrode sheet 101 to be tested, the first diaphragm 102 and the non-adhesive diaphragm 103. The first unit to be tested 100, the positive electrode sheet 101 to be tested and the non-adhesive diaphragm 103 can be measured separately, and the thickness of the first unit to be tested 100, the thickness of the positive electrode sheet 101 to be tested and the thickness of the non-adhesive diaphragm 103 can be measured.

[0066] See also Figure 7As shown, in one embodiment of the present invention, the first unit to be tested 100 is subjected to hot pressing. When hot pressing is performed at a preset pressure and temperature, the thickness of the positive electrode sheet 101 to be tested, the first diaphragm 102, and the non-adhesive diaphragm 103 will change. At the same time, during the hot pressing process, the first adhesive layer 1020 and the second adhesive layer 1021 will change and bond with the positive electrode sheet 101 to be tested and the non-adhesive diaphragm 103, so it is impossible to measure the thickness of the positive electrode sheet 101 to be tested, the first diaphragm 102, and the non-adhesive diaphragm 103 after hot pressing separately. At this time, the thickness of the first unit to be tested 100 after hot pressing is measured.

[0067] See also Figures 4 to 5 As shown, in one embodiment of the present invention, the thickness of the target positive electrode sheet 201 and the second separator 202 will change through hot pressing. Specifically, the compression rate T2 of the second separator can be obtained by the following formula: T2 = (h5-h7) / h5. Among them, h5 is the thickness of the second separator 202, and h7 is the thickness of the second separator 202 after hot pressing.

[0068] See also Figure 6 to Figure 7 As shown, in one embodiment of the present invention, after the hot pressing treatment, the first diaphragm 102 is bonded to the positive electrode sheet 101 to be tested and the non-adhesive diaphragm 103, so the thickness of the positive electrode sheet 101 to be tested, the first diaphragm 102 and the non-adhesive diaphragm 103 after hot pressing cannot be directly measured. Specifically, the thickness H2 of the first diaphragm after hot pressing can be obtained by the following formula: H2 = h3-h2×(1-T1)-(h11+h12)×(1-T2). Among them, h2 is the thickness of the positive electrode sheet 101 to be tested, h3 is the thickness of the first unit 100 to be tested after hot pressing, T1 is the compression rate of the positive electrode sheet, and h11 and h12 are the thickness of the non-adhesive diaphragm 103 on both sides of the positive electrode sheet 101 to be tested.

[0069] See also Figure 5 As shown, in one embodiment of the present invention, the compression rate W2 of the first diaphragm can be obtained by the following formula: W2=1-H2 / (h8-h9-h11-h12). Wherein, H2 is the thickness of the first diaphragm after hot pressing, h8 is the thickness of the first unit to be tested 100, h9 is the thickness of the positive electrode sheet 101 to be tested, and h11 and h12 are the thickness of the non-coated diaphragm 103 on both sides of the positive electrode sheet 101 to be tested.

[0070] See also Figures 2 to 8As shown, in one embodiment of the present invention, the thickness of the unit to be compressed 303 is measured by the measuring unit 301. In this embodiment, the measuring unit 301 is provided with, for example, a laser thickness gauge to measure the thickness. At the same time, the thickness can also be measured by the operator using a micrometer or a ten-thousandth caliper. Before hot pressing, it is necessary to measure the thickness of the first unit to be tested 100, the positive electrode sheet to be tested 101, the non-coated diaphragm 103, the target positive electrode sheet 201, and the second diaphragm 202. After hot pressing, it is necessary to measure the thickness of the first unit to be tested 100, the target positive electrode sheet 201, and the second diaphragm 202 after hot pressing. Among them, the unit to be compressed 303 is hot pressed by the compression unit 302. The unit to be compressed 303 can be a core package containing the first unit to be tested 100, or a core package containing the second unit to be tested 200. The compression unit 302 presets the temperature and pressure, and compresses the unit to be compressed 303. At the same time, the same hot pressing parameters are used in each hot pressing process to ensure the accuracy of the test data.

[0071] See also Figures 2 to 8 As shown, in one embodiment of the present invention, based on the measurement data before hot pressing and the measurement data after hot pressing, the compression rate of the diaphragm is calculated through the processing unit 304 according to the thickness values ​​of the positive electrode sheet and the diaphragm before and after hot pressing and the corresponding calculation formula.

[0072] Please refer to 2 to Fig. 9 As shown, in one embodiment of the present invention, the diaphragm compression rate detection device 400 includes an acquisition module 401. Through the acquisition module 401, the electrode and diaphragm required for the laminated winding battery cell are determined. Among them, positive electrode sheets and negative electrode sheets with different polarities are arranged on both sides of the diaphragm. In this embodiment, the compression rate of the diaphragm is mainly calculated by the difference in thickness changes of the positive electrode sheet and the diaphragm. At the same time, through the acquisition module 401, a first unit to be tested 100 and a second unit to be tested 200 are provided. For the first diaphragm 102 included in the first unit to be tested 100, for example, a single-sided glue-coated diaphragm or a double-sided glue-coated diaphragm is provided. If a double-sided glue-coated diaphragm is used, it is necessary to add a non-glue-coated diaphragm 103 to the double-sided glue-coated diaphragm so that the first unit to be tested is not bonded to the negative electrode sheet, so as to detect the compression rate of the diaphragm. For the second diaphragm 202 included in the second unit to be tested 200, for example, a non-glue diaphragm is provided. The non-adhesive separator is not bonded to the target positive electrode sheet 201, so that the thickness change difference between the target positive electrode sheet 201 and the second separator 202 can be obtained separately, further facilitating the detection of the separator compression rate.

[0073] Please refer to 2 to Fig. 9As shown, in one embodiment of the present invention, the diaphragm compression rate detection device 400 includes a measuring module 402. The thickness measurement data of the diaphragm and the electrode of the first unit to be tested 100 are statistically analyzed by the measuring module 402. In this embodiment, a laser thickness gauge can be used to measure the thickness, or the operator can use a micrometer and a ten-thousandth caliper to measure the thickness. If the first diaphragm 101 adopts a single-sided glue-coated diaphragm, the thickness of the first unit to be tested 100 and the positive electrode plate 101 to be tested before hot pressing is first measured, and after the first unit to be tested 100 is hot-pressed, the thickness of the first unit to be tested 100 after hot pressing is measured. If the first diaphragm 101 adopts a double-sided glue-coated diaphragm, the thickness of the non-glue-coated diaphragm 103 needs to be measured separately. Through the different measured data, it can be concluded that the positive electrode plate and the diaphragm have undergone compression changes during the hot pressing process.

[0074] Please refer to 2 to Fig. 9 As shown, in one embodiment of the present invention, the thickness measurement data of the positive electrode sheet and the non-adhesive separator of the second unit under test 200 are counted by the measurement module 402. First, the thickness of the target positive electrode sheet 201 and the second separator 202 before hot pressing is measured, and after the second unit under test 200 is hot pressed, the thickness of the target positive electrode sheet 201 and the second separator 202 after hot pressing is measured, so as to obtain the compression rate of the target positive electrode sheet 201 and the second separator 202.

[0075] Please refer to 2 to Fig. 9 As shown, in one embodiment of the present invention, the diaphragm compression rate detection device 400 includes a compression module 403. Through the compression module 403, the first unit under test 100 and the second unit under test 200 are subjected to hot pressing treatment, and the thickness change value of the pole piece and the diaphragm after hot pressing is recorded, and the same hot pressing parameters are set in each hot pressing.

[0076] Please refer to 2 to Fig. 9 As shown, in one embodiment of the present invention, the diaphragm compression rate detection device 400 includes a processing module 404. Through the processing module 404, according to the measured thickness difference of the first unit to be tested 100 before and after hot pressing, the thickness of the positive electrode sheet 101 to be tested and the thickness of the non-coated diaphragm 103, and the obtained compression rate of the target positive electrode sheet 201 and the second diaphragm 202, and according to different settings of the first diaphragm 101, different calculation methods are used to finally calculate the compression rate of the first diaphragm 101.

[0077] In summary, the present invention provides a method for detecting the compression rate of a diaphragm, wherein a first unit to be tested 100 and a second unit to be tested 200 are provided, and a first diaphragm 102 and a second diaphragm 202 can be provided on both sides of the positive electrode sheet 101 to be tested and the target positive electrode sheet 201, respectively. The thickness of the first unit to be tested 100, the thickness of the positive electrode sheet 101 to be tested, the thickness of the target positive electrode sheet 201, and the thickness of the second diaphragm 202 are measured by a measuring unit 301. If the first diaphragm 102 is coated with glue on both sides, the thickness of the non-coated diaphragm 103 bonded to the target positive electrode sheet 201 needs to be measured separately. Then, the first unit to be tested 100 and the second unit to be tested 200 are subjected to hot pressing treatment by a compression unit 302, and the thickness of the first unit to be tested 100, the target positive electrode sheet 201, and the second diaphragm 202 after hot pressing are measured. Finally, the compression rate of the diaphragm is calculated based on the difference in thickness before and after hot pressing of the electrode sheet and the diaphragm.

[0078] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for detecting diaphragm compression rate, characterized in that: The following steps are involved: Providing a first unit to be tested, the first unit to be tested comprising a positive electrode sheet to be tested and a first diaphragm attached to two sides of the positive electrode sheet to be tested; Measuring the thickness of the first unit to be tested and the positive electrode sheet to be tested to obtain the thickness of the first diaphragm; Providing a second unit to be tested, the second unit to be tested comprising a target positive electrode sheet and a second diaphragm attached to two sides of the target positive electrode sheet; Measuring the thickness of the target positive electrode sheet and the second separator; Performing hot pressing treatment on the first unit to be tested and the second unit to be tested, and measuring the thickness of the first unit to be tested, the target positive electrode sheet, and the second diaphragm after hot pressing; wherein the same hot pressing parameters are set in each hot pressing; Obtaining the thickness of the first diaphragm after hot pressing according to the thickness of the positive electrode sheet to be tested, the thickness of the first unit to be tested after hot pressing, and the difference in thickness of the target positive electrode sheet before and after hot pressing; and Obtaining a diaphragm compression rate according to the thickness of the first diaphragm and the thickness of the first diaphragm after hot pressing; The compression rate of the positive electrode sheet is obtained by the thickness difference before and after hot pressing of the target positive electrode sheet; the compression rate of the positive electrode sheet T1 is expressed as: T1=(h4-h6) / h4, h4 is the thickness of the target positive electrode sheet before hot pressing, and h6 is the thickness of the target positive electrode sheet after hot pressing; The thickness H1 of the first diaphragm after hot pressing is expressed as: H1=h3-h2×(1-T1), h2 is the thickness of the positive electrode sheet to be tested, h3 is the thickness of the first unit to be tested after hot pressing, and T1 is the compression rate of the positive electrode sheet.

2. A diaphragm compression rate detection method according to claim 1, characterized in that: The first diaphragm is a single-sided adhesive-coated diaphragm, and the adhesive layer of the single-sided adhesive-coated diaphragm is bonded to the positive electrode sheet to be tested.

3. A diaphragm compression rate detection method according to claim 1, characterized in that: The thickness of the positive electrode sheet to be tested after hot pressing is obtained according to the thickness of the positive electrode sheet to be tested and the compression rate of the positive electrode sheet.

4. A diaphragm compression rate detection method according to claim 1, characterized in that: The first diaphragm is a double-sided adhesive-coated diaphragm, and the adhesive layer on one side of the double-sided adhesive-coated diaphragm is bonded to the positive electrode sheet to be tested, and the adhesive layer on the other side is bonded to the non-adhesive-coated diaphragm.

5. A diaphragm compression rate detection method according to claim 4, characterized in that: Obtaining the thickness of the first diaphragm after hot pressing comprises the following steps: measuring the thickness of the non-adhesive diaphragm; Obtaining a compression rate of the second diaphragm according to the thickness of the second diaphragm and the thickness of the second diaphragm after hot pressing; According to the thickness of the non-glue-coated diaphragm and the compression rate of the second diaphragm, the thickness of the non-glue-coated diaphragm after hot pressing is obtained; Obtaining the thickness of the positive electrode sheet to be tested after hot pressing according to the difference between the thickness of the positive electrode sheet to be tested and the thickness of the target positive electrode sheet before and after hot pressing; and The thickness of the first diaphragm after hot pressing is obtained through the thickness of the unit to be tested after hot pressing, the thickness of the positive electrode sheet to be tested after hot pressing and the thickness of the non-glue-coated diaphragm after hot pressing.

6. A diaphragm compression rate detection method according to claim 5, characterized in that: The compression rate of the separator is obtained according to the thickness of the positive electrode sheet to be tested, the thickness of the first separator and the thickness of the first separator after hot pressing.

7. A diaphragm compression rate detection device, characterized in that: include: The first unit to be tested comprises a positive electrode sheet to be tested and a first diaphragm attached to two sides of the positive electrode sheet to be tested; The second unit to be tested includes a target positive electrode sheet and a second diaphragm attached to two sides of the target positive electrode sheet; an acquisition module, through which the first unit under test and the second unit under test are provided; A compression module, through which the first unit under test and the second unit under test are subjected to a heat pressing process; wherein the same heat pressing parameters are set during each heat pressing process; A measuring module, used to measure the thickness of the first unit to be tested and the positive electrode sheet to be tested, and obtain the thickness of the first diaphragm; measure the thickness of the target positive electrode sheet and the second diaphragm before and after hot pressing; measure the thickness of the first unit to be tested, the target positive electrode sheet and the second diaphragm after hot pressing; wherein the thickness H1 of the first diaphragm after hot pressing is expressed as: H1=h3-h2×(1-T1), h2 is the thickness of the positive electrode sheet to be tested, h3 is the thickness of the first unit to be tested after hot pressing, and T1 is the compression rate of the positive electrode sheet; and A processing module is used to calculate the compression rate of the diaphragm according to the processing module; it is also used to obtain the compression rate of the positive electrode sheet through the thickness difference before and after hot pressing of the target positive electrode sheet; the compression rate of the positive electrode sheet T1 is expressed as: T1 = (h4-h6) / h4, h4 is the thickness of the target positive electrode sheet before hot pressing, and h6 is the thickness of the target positive electrode sheet after hot pressing.

8. A diaphragm compression rate detection device according to claim 7, characterized in that: The measuring module adopts a laser thickness gauge.

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