Device and method for testing density of bonding layer

Abstract

The invention relates to a device and a method for testing the density of a bonding layer. The device for testing the density of the bonding layer comprises a dissolution reaction device and a heating device, the dissolution reaction device is used for accommodating a solvent; wherein the solvent is used for dissolving a bonding layer of a diaphragm to be tested, which is soaked in the dissolution reaction device; the heating device is used for heating the solvent. According to the technical scheme, the density of the bonding layer of the diaphragm can be accurately measured as much as possible by utilizing the solubility difference of different structures of the diaphragm in the solvent, a basis is provided for evaluating the quality of the diaphragm and the like, and the method is simple and easy to operate.

Description

Technical Field

[0001] The present disclosure relates to the field of lithium - ion batteries, and particularly to a test device and a test method for the surface density of an adhesive layer. Background Art

[0002] As a material for isolating the positive and negative electrodes in a lithium - ion battery, the separator not only affects the battery performance, but also has an important impact on improving the battery processing technology. In order to achieve a good state of the cell hardness, the separator is usually coated with an adhesive on one or both sides as an adhesive layer, so that the separator and the positive and negative electrode plates can be closely laminated. However, the use of the adhesive generally affects the battery internal resistance and energy density. Too high surface density of the adhesive layer will lead to an increase in the battery internal resistance, an increase in the separator thickness, and a decrease in the battery energy density; too low surface density of the adhesive layer will weaken the bonding effect between the separator and the electrode plate, resulting in an increase in the process time, a reduction in the battery manufacturing efficiency, and an impact on the battery manufacturing cost.

[0003] It can be seen that the surface density of the adhesive layer of the lithium - ion battery separator has a high impact on the battery performance, manufacturing cost, etc. Therefore, the surface density of the adhesive layer is one of the important indicators for evaluating the separator performance. Therefore, there is an urgent need for a device and a method that can accurately measure the surface density of the adhesive layer of the separator. Summary of the Invention

[0004] In order to solve the above - mentioned technical problems, the present disclosure provides a test device and a test method for the surface density of an adhesive layer, which can measure the surface density of the adhesive layer of the separator as accurately as possible, provide a basis for evaluating the separator quality, etc., and the method is simple and easy to operate.

[0005] In a first aspect, the present disclosure provides a test device for the surface density of an adhesive layer, including:

[0006] A dissolution reaction device and a heating device;

[0007] The dissolution reaction device is used to contain a solvent; wherein, the solvent is used to dissolve the adhesive layer of the separator to be tested soaked in the dissolution reaction device;

[0008] The heating device is used to heat the solvent.

[0009] Optionally, the heating device includes an oven, and the dissolution reaction device is located inside the oven;

[0010] The oven includes an exhaust component, and the exhaust component discharges the gas inside the oven to the external environment through a gas discharge pipe.

[0011] Optionally, it further includes: a cleaning agent containing device, which is used to contain a cleaning agent; the cleaning agent is used to clean the impurities on the separator to be tested.

[0012] Optionally, it further includes: a sample accommodating device and a lifting device;

[0013] The sample accommodating device is installed on the lifting device and is used for placing the diaphragm to be tested;

[0014] The lifting device drives the sample accommodating device to move so that the sample accommodating device is immersed in the solvent in the dissolution reaction device.

[0015] Optionally, the sample accommodating device includes a sample accommodating box and a sample accommodating plate;

[0016] The sample accommodating plate is detachably installed in the sample accommodating box;

[0017] An opening is provided on the sample accommodating plate, and at least one surface of the sample accommodating box is provided with an opening.

[0018] Optionally, the lifting device includes: a suspension rod, a support rod, a lifting adjustment mechanism and a suspension assembly;

[0019] The sample accommodating device is connected to the suspension rod through the suspension assembly, the suspension rod is connected to the support rod through the lifting adjustment mechanism, and the lifting adjustment mechanism controls the movement of the suspension rod relative to the support rod.

[0020] Optionally, the solvent includes a dipolar aprotic compound solvent.

[0021] In a second aspect, the present disclosure also provides a method for testing the density of the bonding layer, which is applicable to the testing device for the density of the bonding layer as described in the first aspect; the method includes:

[0022] Obtaining the mass of the diaphragm to be tested before being immersed in the dissolution reaction device as the first mass;

[0023] Immersing the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the bonding layer of the diaphragm to be tested;

[0024] Obtaining the mass of the diaphragm to be tested after dissolving the bonding layer as the second mass;

[0025] Determining the density of the bonding layer of the diaphragm to be tested according to the first mass, the second mass and the area of the diaphragm to be tested.

[0026] Optionally, the testing device for the density of the bonding layer further includes: a cleaning agent accommodating device, which is used for accommodating a cleaning agent; the cleaning agent is used for cleaning impurities on the diaphragm to be tested;

[0027] After soaking the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested, the following steps are further included:

[0028] Put the diaphragm to be tested after dissolving the adhesive layer into the cleaning agent containing device for cleaning.

[0029] Optionally, the test device for the areal density of the adhesive layer further includes: a cleaning agent containing device for containing a cleaning agent; the cleaning agent is used to clean impurities on the diaphragm to be tested;

[0030] After soaking the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested, the following steps are further included:

[0031] Put the diaphragm to be tested after dissolving the adhesive layer into the cleaning agent containing device for cleaning.

[0032] The technical solution provided by the present disclosure has the following advantages compared with the related art:

[0033] The present disclosure provides a test device and a test method for the areal density of an adhesive layer. The test device for the areal density of the adhesive layer includes: a dissolution reaction device and a heating device; the dissolution reaction device is used to contain a solvent; wherein, the solvent is used to dissolve the adhesive layer of the diaphragm to be tested soaked in the dissolution reaction device; the heating device is used to heat the solvent. Thus, by using the difference in the solubility of the base film, ceramic layer and adhesive layer in the diaphragm in the solvent, and soaking the diaphragm to be tested with a solvent that only dissolves the adhesive layer of the diaphragm to be tested, the areal density of the adhesive layer can be measured as accurately as possible, providing a basis for evaluating the diaphragm quality, evaluating the diaphragm processing performance, etc., and the method is simple and easy to operate. Description of the Drawings

[0034] The drawings here are incorporated into the description and form a part of this description, showing embodiments consistent with the present disclosure, and are used together with the description to explain the principles of the present disclosure.

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the related art, the following will briefly introduce the drawings required for use in the description of the embodiments or the related art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0036] Figure 1 It is a schematic structural diagram of a test device for the areal density of an adhesive layer provided by an embodiment of the present disclosure;

[0037] Figure 2 It is a schematic structural diagram of a sample container provided by an embodiment of the present disclosure;

[0038] Figure 3 Schematic flow diagram of a method for testing the surface density of an adhesive layer provided by an embodiment of the present disclosure.

[0039] Among them, 1. Dissolution reaction device; 2. Cleaning agent containing device; 3. Oven; 4. Sample containing device; 5. Lifting device; 6. Placement table; 7. Chain track; 31. Temperature adjustment button; 32. Oven switch; 33. Oven handle; 34. Temperature display panel; 35. Exhaust component; 41. Sample containing box; 42. Sample containing plate; 51. Suspension rod; 52. Support rod; 53. Lifting adjustment mechanism; 54. Suspension component; 531. Positioning frame; 532. Thread adjustment rod. Detailed implementation manners

[0040] In order to more clearly understand the above objects, features, and advantages of the present disclosure, the solutions of the present disclosure will be further described below. It should be noted that, without conflict, the embodiments of the present disclosure and the features in the embodiments may be combined with each other.

[0041] Many specific details are set forth in the following description in order to fully understand the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present disclosure, rather than all the embodiments.

[0042] The surface density of the adhesive layer of a lithium-ion battery separator has a relatively high impact on the performance and manufacturing cost of the battery. Therefore, the surface density of the adhesive layer is one of the important indicators for evaluating the performance of the separator. Therefore, there is an urgent need for a device and method that can accurately measure the surface density of the adhesive layer of the separator.

[0043] Figure 1 Schematic structural diagram of a device for testing the surface density of an adhesive layer provided by an embodiment of the present disclosure, as Figure 1 shown, the device for testing the surface density of the adhesive layer includes: a dissolution reaction device 1 and a heating device; the dissolution reaction device 1 is used to contain a solvent; wherein, the solvent is used to dissolve the adhesive layer of the separator to be tested soaked in the dissolution reaction device 1; the heating device is used to heat the solvent.

[0044] Specifically, as Figure 1 shown, there are differences in the solubility of the base film, ceramic layer, and adhesive layer on the separator in the solvent. Therefore, a solvent that can dissolve the adhesive layer of the separator and will not dissolve the base film and ceramic layer can be filled into the dissolution reaction device 1 to ensure that the mass difference of the separator to be tested before and after being soaked in the solvent is only the mass of the adhesive layer.

[0045] Before the diaphragm to be tested is immersed in the solvent, the diaphragm to be tested is weighed first, and the mass of the diaphragm to be tested is obtained as the first mass M1. Then the diaphragm to be tested is placed into a dissolution reaction device, and the solvent completely submerges the diaphragm to be tested to dissolve the adhesive layer of the diaphragm to be tested. During the process of the diaphragm to be tested being immersed in the solvent, a heating device is used to heat the solvent to increase the solubility and dissolution rate of the adhesive layer in the solvent.

[0046] Exemplarily, taking the solvent as N-methyl-2-pyrrolidone (NMP) as an example, the heating temperature is, for example, 60 °C to 80 °C. On the one hand, it can increase the solubility and dissolution rate of the adhesive layer in the solvent. On the other hand, it can also avoid the problems of excessive solvent volatilization and consumption caused by too high heating temperature, as well as the impact of excessive solvent volatilization on human health.

[0047] After the diaphragm to be tested is immersed in the solvent for a preset time, the diaphragm to be tested is taken out of the solvent, and the weight of the diaphragm to be tested is weighed as the second mass M2. The difference between the first mass M1 and the second mass M2 is the mass of the dissolved adhesive layer of the diaphragm to be tested. Therefore, the surface density of the adhesive layer can be calculated according to the first mass M1, the second mass M2, and the area S of the diaphragm to be tested. The calculation formula for the surface density ρ of the adhesive layer is as follows:

[0048]

[0049] Wherein, M1 is the mass of the diaphragm to be tested before being immersed in the solvent, with the unit of g; M2 is the mass of the diaphragm to be tested after being immersed in the solvent, with the unit of g; S is the area of the diaphragm to be tested, with the unit of m 2 .

[0050] In the embodiment of the present disclosure, the solvent only dissolves the adhesive layer of the diaphragm to be tested. The diaphragm to be tested before and after being immersed in the solvent is weighed, and the mass difference between the diaphragm to be tested before and after immersion is used as the mass of the adhesive layer of the diaphragm to be tested. The surface density of the diaphragm adhesive layer is calculated by using the mass of the adhesive layer of the diaphragm to be tested and the area of the diaphragm to be tested. By using the difference in solubility of the base film, ceramic layer, and adhesive layer in the diaphragm in the solvent, the solvent that only dissolves the adhesive layer of the diaphragm to be tested is used to immerse the diaphragm to be tested, and the surface density of the adhesive layer is measured as accurately as possible, providing a basis for evaluating the diaphragm quality, evaluating the diaphragm processing performance, etc. The method is simple and easy to operate.

[0051] Optionally, as Figure 1 shown, the heating device includes an oven 3, and the dissolution reaction device 1 is located inside the oven 3; the oven 3 includes an exhaust component 35, and the exhaust component 35 discharges the gas inside the oven 3 to the external environment through a gas discharge pipe.

[0052] Specifically, as Figure 1As shown, the dissolution reaction device 1 can be arranged inside the oven 3, and the temperature of the oven 3 can be adjusted to reach the preset heating temperature, such as 60°C to 80°C. Sealing strips can be arranged around the opening of the oven 3 to reduce the temperature fluctuation range inside the oven 3, making the temperature of the solvent in the dissolution reaction device 1 more stable, and the dissolution rate of the solvent to the adhesive layer of the diaphragm to be tested more stable.

[0053] Figure 1 Exemplarily shown in the figure, the oven 3 includes a temperature adjustment button 31, an oven switch 32, an oven handle 33, and a temperature display panel 34. The experimenter can start or stop the oven 3 through the oven switch 32, adjust the temperature of the oven 3 through the temperature adjustment button 31. The temperature display panel 34 is used to display the current temperature of the oven 3, and the oven handle 33 facilitates the experimenter to take the experimental supplies inside the oven 3.

[0054] In addition, an exhaust component 35 is also arranged on the oven 3. The exhaust component 35 is, for example, an exhaust fan. The exhaust component 35 can be arranged, for example, on the back of the box body of the oven 3. The exhaust component 35 is connected with a gas discharge pipe. The exhaust component 35 discharges the gas volatilized from the solvent inside the oven 3 to the external environment through the gas discharge pipe to avoid the toxic gas volatilized from the solvent affecting human health. Exemplarily, during the process of the solvent dissolving the adhesive layer of the diaphragm to be tested, the exhaust component 35 can be controlled to be closed to keep the temperature inside the oven 3 in a stable state.

[0055] In some embodiments, as Figure 1 shown, the dissolution reaction device 1 and the cleaning agent accommodating device 2 can be arranged on the placement table 6, and the placement table 6 is connected with the box body of the oven 3 through a chain track 7.

[0056] In some embodiments, the heating device can also be, for example, a heating table. The dissolution reaction device 1 is arranged on the heating table, and the heating table is used to heat the solvent. The specific heating principle of the heating table is well known to those skilled in the art and will not be limited herein.

[0057] Optionally, as Figure 1 shown, the test device for the adhesive layer surface density further includes: a cleaning agent accommodating device 2, and the cleaning agent accommodating device 2 is used to accommodate a cleaning agent; the cleaning agent is used to clean the impurities on the diaphragm to be tested.

[0058] Specifically, as Figure 1 shown, the test device for the adhesive layer surface density further includes a cleaning agent accommodating device 2, and the cleaning agent accommodating device 2 is used to accommodate a cleaning agent. The cleaning agent can be, for example, ethanol. After the diaphragm to be tested is taken out from the solvent in the dissolution reaction device 1, ethanol is used to clean the diaphragm to be tested to remove the residual adhesive layer and contaminants and other impurities on the diaphragm to be tested. In addition, ethanol is volatile, reducing the difficulty of drying the cleaned diaphragm to be tested.

[0059] Thereby, the test accuracy of the bonding layer density is improved, and the problem that the impurities remaining on the diaphragm to be tested affect the weighing accuracy is avoided.

[0060] Optionally, as Figure 1 shown, the test device for the bonding layer density further includes: a sample accommodating device 4 and a lifting device 5; the sample accommodating device 4 is installed on the lifting device 5 and is used for placing the diaphragm to be tested; the lifting device 5 drives the sample accommodating device 4 to move so that the sample accommodating device 4 is immersed in the solvent in the dissolution reaction device 1.

[0061] Specifically, as Figure 1 shown, the sample accommodating device 4 is installed on the lifting device 5, the diaphragm to be tested is placed in the sample accommodating device 4, and the lifting device 5 can drive the sample accommodating device 4 to move so that the diaphragm to be tested in the sample accommodating device 4 is immersed in the solvent in the dissolution reaction device 1.

[0062] Exemplarily, taking the Figure 1 relative position relationship as an example, before testing the bonding layer density, the sample accommodating device 4 is suspended above the lifting device 5. When it is necessary to test the bonding layer density, the diaphragm to be tested is placed in the sample accommodating device 4, and the lifting device 5 drives the sample accommodating device 4 to descend so that the diaphragm to be tested in the sample accommodating device 4 is immersed in the solvent in the dissolution reaction device 1. After the solvent dissolves the bonding layer, the lifting device 5 can also drive the sample accommodating device 4 to rise so that the diaphragm to be tested in the sample accommodating device 4 is separated from the solvent in the dissolution reaction device 1.

[0063] Optionally, as Figure 1 shown, the lifting device 5 includes: a suspension rod 51, a support rod 52, a lifting adjustment mechanism 53 and a suspension assembly 54; the sample accommodating device 4 is connected to the suspension rod 51 through the suspension assembly 54, the suspension rod 51 is connected to the support rod 52 through the lifting adjustment mechanism 53, and the lifting adjustment mechanism 53 controls the movement of the suspension rod 51 relative to the support rod 52.

[0064] Exemplarily, as Figure 1 shown, hanging holes can be provided at both ends of the upper layer of the sample accommodating device 4, and the suspension assembly 54, such as a hanging rope, passes through the hanging holes to connect the sample accommodating device 4 to the suspension rod 51. The lifting adjustment mechanism 53 can, for example, include a positioning frame 531 and a threaded adjustment rod 532. The positioning frame 531 is provided outside the support rod 52, the suspension rod 51 penetrates through the positioning frame 531, and the up and down movement of the positioning frame 531 relative to the support rod 52 drives the up and down movement of the suspension rod 51 relative to the support rod 52. The threaded adjustment rod 532 extends out of the positioning frame 531, and the threaded adjustment rod 532 is threadedly connected to the positioning frame 531.

[0065] When it is necessary to adjust the height of the sample holding device 4, loosen the threaded adjusting rod 532. The frictional force between the threads decreases, and the positioning frame 531 drives the suspension rod 51 to move up and down along the support rod 52. After adjusting to the appropriate height, tighten the threaded adjusting rod 532. The threads generate a large frictional force to fix the suspension rod 51 in the corresponding position, thereby realizing the functions of lifting and fixing the sample holding device 4.

[0066] When it is necessary to adjust the position of the sample holding device 4 so that the sample holding device 4 is placed corresponding to the cleaning agent holding device 2, loosen the threaded adjusting rod 532. The frictional force between the threads decreases, and rotate the suspension rod 51 to rotate the sample holding device 4 to one side of the cleaning agent holding device 2. After adjusting to the appropriate position, tighten the threaded adjusting rod 532.

[0067] Optionally, as Figure 1 shown, the sample holding device 4 includes a sample holding box 41 and a sample holding plate; the sample holding plate is detachably installed in the sample holding box 41; an opening is provided on the sample holding plate, and at least one surface of the sample holding box 41 is provided with an opening.

[0068] Specifically, as Figure 1 shown, the sample holding box 41 can be suspended on the lifting device 5 through a suspension assembly 54 such as a hanging rope. In order to accommodate more diaphragm samples to be tested, multiple layers of sample holding plates can be detachably arranged in the sample holding box 41. When measuring the bonding layer density, lay the diaphragm to be tested flat on the sample holding plate. Multiple sample holding plates can be stacked and placed in the sample holding box 41. Multiple diaphragm samples to be tested located on multiple sample holding plates can be simultaneously immersed in the solvent of the dissolution reaction device 1, improving the test efficiency of the bonding layer density. The specific number of sample holding plates can be adjusted according to the number of diaphragms to be tested, and the embodiments of the present disclosure do not limit this.

[0069] An opening is provided on at least one surface of the sample holding box 41 to enable the solvent to enter the sample holding box 41 and soak the diaphragm to be tested. An opening is also provided on the sample holding plate to enable the diaphragm to be tested on the sample holding plate to be in full contact with the solvent and improve the dissolution efficiency.

[0070] The sample holding device may also include, for example, a sample holder, and the sample holder is composed of the sample holding plates provided by the embodiments of the present disclosure. Figure 2 As a schematic structural diagram of a sample holder provided by an embodiment of the present disclosure, as Figure 2 shown, at least one layer of sample holding plates 42 is arranged in the sample holder. When measuring the bonding layer density, the weighed diaphragm samples to be tested can be laid flat and placed on the sample holding plates 42 of the sample holder, and then the entire sample holder is placed in the sample holding box 41 to improve the test efficiency and avoid the problem of diaphragm wrinkles.

[0071] In some embodiments, the sample holding plate 42 can also be directly placed in the sample holding box 41, and the embodiments of the present disclosure do not limit this.

[0072] In some embodiments, the materials of the dissolution reaction device 1, the cleaning agent holding device 2, and the sample holding device 4 provided by the embodiments of the present disclosure are any one of stainless steel, fiberglass, and polypropylene (PP) to avoid corrosion of the solvent on them.

[0073] Optionally, the solvent includes a dipolar aprotic compound solvent.

[0074] Specifically, the solvent can include, for example, at least one of dimethylacetamide, N,N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, N-methyl-2-pyrrolidone, triethyl phosphate, trimethyl phosphate, and tetramethylurea. The above solvents can dissolve the adhesive layer of the diaphragm to be tested, but do not dissolve the components in the base film and ceramic layer of the diaphragm, so as to ensure that the mass difference of the diaphragm to be tested before and after being immersed in the solvent is only the mass of the adhesive layer, improving the accuracy of the adhesive layer surface density test.

[0075] The embodiments of the present disclosure also provide a method for testing the surface density of the adhesive layer, which is applicable to the testing device for the surface density of the adhesive layer provided in the above embodiments. Figure 3 It is a schematic flow chart of a method for testing the surface density of the adhesive layer provided by the embodiments of the present disclosure. The method for testing the surface density of the adhesive layer can be applied to application scenarios that require control of the testing device for the surface density of the adhesive layer. As Figure 3 shown, the method includes the following steps:

[0076] S101. Obtain the mass of the diaphragm to be tested before being immersed in the dissolution reaction device as the first mass.

[0077] Specifically, take the lithium-ion battery diaphragm cut into an area S as the diaphragm to be tested, and weigh the diaphragm to be tested that is not immersed in the solvent of the dissolution reaction device, record the mass as the first mass M1, and the weighing instrument can be, for example, an electronic balance.

[0078] S102. Immerse the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested.

[0079] Specifically, immerse the diaphragm to be tested in the solvent of the dissolution reaction device for a preset time, and heat the solvent at the same time to improve the solubility of the solvent in the adhesive layer. Taking the solvent as N-methyl-2-pyrrolidone (NMP) as an example, the heating temperature of the solvent can be 60°C to 80°C.

[0080] It should be noted that the soaking time of the diaphragm to be tested in the solvent can be determined according to the area of the diaphragm to be tested, and the embodiments of the present disclosure do not limit this.

[0081] It should be noted that the heating temperature of the solvent can be determined according to the dissolution property of the solvent to the adhesive layer, and the embodiments of the present disclosure do not limit this.

[0082] S103. Obtain the mass of the diaphragm to be tested after dissolving the adhesive layer as the second mass.

[0083] Specifically, take out the diaphragm to be tested after dissolving the adhesive layer from the dissolution reaction device, weigh it, and use its mass as the second mass M2.

[0084] S104. Determine the surface density of the adhesive layer of the diaphragm to be tested according to the first mass, the second mass, and the area of the diaphragm to be tested.

[0085] The specific calculation formula of the surface density of the adhesive layer can be understood with reference to the above embodiments, and will not be elaborated here.

[0086] Optionally, the test device for the surface density of the adhesive layer further includes: a cleaning agent accommodating device for accommodating a cleaning agent; the cleaning agent is used to clean the impurities on the diaphragm to be tested;

[0087] After soaking the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested, it further includes: putting the diaphragm to be tested after dissolving the adhesive layer into the cleaning agent accommodating device for cleaning.

[0088] Specifically, after the solvent dissolves the adhesive layer of the diaphragm to be tested, impurities such as the dissolved adhesive layer and pollutants may remain on the surface of the diaphragm to be tested. In order to improve the accuracy of the surface density test of the adhesive layer and avoid the influence of impurities on the weighing of the diaphragm to be tested, it is necessary to put the diaphragm to be tested after dissolving the adhesive layer into the cleaning agent accommodating device for cleaning to remove the impurities on the surface of the diaphragm to be tested, improve the weighing accuracy, and further improve the accuracy of the surface density test of the adhesive layer.

[0089] Optionally, the test device for the surface density of the adhesive layer further includes: a sample accommodating device and a lifting device; the sample accommodating device is used to place the diaphragm to be tested and is installed on the lifting device; the lifting device drives the sample accommodating device to move so that the sample accommodating device is immersed in the solvent in the dissolution reaction device;

[0090] Soaking the diaphragm to be tested in the solvent in the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested includes: controlling the lifting device to drive the sample accommodating device to move so that the sample accommodating device is immersed in the solvent in the dissolution reaction device.

[0091] Specifically, the sample holding device is mounted on the lifting device through a lanyard. The lifting device can drive the sample holding device to move to adjust the position of the sample holding device, so that the sample holding device is immersed in the solvent in the dissolution reaction device. The specific adjustment method can be understood with reference to the above embodiments and will not be elaborated here.

[0092] The following is an example description of the test method for the density of the bonding layer.

[0093] First step, cut the lithium-ion battery separator into multiple test diaphragms with an area of S, and weigh each test diaphragm separately, and record the mass as the first mass M1.

[0094] Second step, lay the test diaphragm flat in the sample container equipped with the sample holding plate, then place the sample container into the sample holding box in the oven, and adjust the heating temperature of the oven to 60 °C, for example, through the temperature control button on the oven.

[0095] Third step, after the temperature stabilizes, lower the sample holding box into the dissolution reaction device through the lifting device and completely immerse it in the solvent of the dissolution reaction device for 2 hours to fully dissolve the bonding layer of the test diaphragm.

[0096] Fourth step, after 2 hours, raise the sample holding box through the lifting device and rotate the lifting device so that the sample holding box is located on one side of the cleaning agent holding device. Then lower the sample holding box into the cleaning agent holding device through the lifting device again and completely immerse it in the cleaning agent of the cleaning agent holding device. After maintaining for 10 minutes, raise the sample holding box through the lifting device to separate the sample holding box from the cleaning agent.

[0097] Fifth step, after drying the test diaphragm for 2 hours in this state, take out the test diaphragm from the oven and weigh it, and record the mass as the second mass M2.

[0098] Sixth step, calculate the density of the bonding layer according to the following formula.

[0099]

[0100] Among them, M1 is the mass of the test diaphragm before being immersed in the solvent, in g, M2 is the mass of the test diaphragm after being immersed in the solvent, in g, and S is the area of the test diaphragm, in m 2 .

[0101] The following will list multiple embodiments and corresponding experimental results to further illustrate the test method for the density of the bonding layer provided by the embodiments of the present disclosure.

[0102] Example 1:

[0103] Cut the diaphragm sample without an adhesive layer made of pure ceramic (denoted as Sample 1) into 5 samples sized 80X100mm, weigh them, record the weights, lay them flat and place them in the sample container. Put the sample container into the sample storage box, set the temperature of the oven to 60°C. After the temperature stabilizes, lower the sample storage box through the lifting device so that the sample storage box is completely immersed in the NMP solvent. After maintaining for 2 hours, turn the sample storage box to the cleaning agent storage device and keep it for 10 minutes. Then raise the sample storage box. After the sample storage box is dried for 2 hours, take out the diaphragm to be tested, weigh the diaphragm to be tested, and calculate the adhesive layer surface density of Sample 1.

[0104] Example 2:

[0105] Cut the diaphragm sample with a ceramic spray adhesive layer (denoted as Sample 2) into 5 samples sized 80X100mm, weigh them, record the weights, lay them flat and place them in the sample container. Put the sample container into the sample storage box, set the temperature of the oven to 60°C. After the temperature stabilizes, lower the sample storage box through the lifting device so that the sample storage box is completely immersed in the NMP solvent. After maintaining for 2 hours, turn the sample storage box to the cleaning agent storage device and keep it for 10 minutes. Then raise the sample storage box. After the sample storage box is dried for 2 hours, take out the diaphragm to be tested, weigh the diaphragm to be tested, and calculate the adhesive layer surface density of Sample 2.

[0106] Example 3:

[0107] Cut the diaphragm sample without a ceramic layer spray adhesive layer (denoted as Sample 3) into 5 samples sized 80X100mm, weigh them, record the weights, lay them flat and place them in the sample container. Put the sample container into the sample storage box, set the temperature of the oven to 60°C. After the temperature stabilizes, lower the sample storage box so that the sample storage box is completely immersed in the NMP solvent. After maintaining for 2 hours, turn the sample storage box to the cleaning agent storage device and keep it for 10 minutes. Then raise the sample storage box. After the sample storage box is dried for 2 hours, take out the diaphragm to be tested, weigh the diaphragm to be tested, and calculate the adhesive layer surface density of Sample 3.

[0108] Example 4:

[0109] The diaphragm sample without the ceramic layer spray-bonding layer (denoted as sample 4) was cut into 5 samples of 80X100 mm in size, weighed, and after recording the weight, it was laid flat and placed in the sample container. The sample container was placed in the sample storage box, the temperature of the oven was set to 60 °C. After the temperature was stable, the sample storage box was lowered so that the sample storage box was completely immersed in the NMP solvent. After 2 hours, the sample storage box was transferred to the cleaning agent storage device and kept for 10 minutes. Subsequently, the sample storage box was raised to the bottom. After the sample storage box was dried for 2 hours, the diaphragm to be tested was taken out, weighed, and the surface density of the bonding layer of sample 4 was calculated.

[0110] Table 1 Surface density of the bonding layer of each embodiment

[0111] Item Areal density 1 Areal density 2 Areal density 3 Areal density 4 Areal density 5 Average value Sample 1 0 0 0 0 0 0 Sample 2 0.81 0.8 0.79 0.78 0.81 0.80 Sample 3 0.57 0.56 0.57 0.58 0.57 0.57 Sample 4 0.39 0.41 0.40 0.39 0.39 0.40

[0112] From the data of sample 1 in Table 1, it can be seen that there is no obvious change in the mass of the diaphragm without the bonding layer before and after soaking, indicating that the solvent will not dissolve the base film and ceramic layer of the diaphragm. The data of samples 2 to 4 show that the test method provided by the embodiments of the present disclosure has accuracy and repeatability, and the results between parallel samples have little difference.

[0113] The test device and test method for the surface density of the bonding layer provided by the embodiments of the present disclosure dissolve the bonding layer of the diaphragm to be tested with a solvent, weigh the diaphragm to be tested before and after soaking in the solvent, and obtain the mass difference of the diaphragm to be tested before and after soaking as the mass of the bonding layer of the diaphragm to be tested. The surface density of the diaphragm bonding layer is calculated by using the mass of the bonding layer of the diaphragm to be tested and the area of the diaphragm to be tested. By using the difference in the solubility of different structures of the diaphragm in the solvent, the surface density of the bonding layer is measured as accurately as possible, providing a basis for evaluating the quality of the diaphragm and the processing performance of the diaphragm, etc. The method is simple and easy to operate. In addition, due to the presence of the bonding layer, the thickness consistency of the coated diaphragm usually becomes worse, and it is difficult to evaluate the thickness consistency of the base film and the ceramic layer. However, the influence of this factor can be excluded after removing the bonding layer in the embodiments of the present disclosure.

[0114] It should be noted that in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variation thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the phrase "including a..." does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0115] The foregoing are only specific embodiments of the present disclosure, enabling those skilled in the art to understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to these embodiments described herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A test device for the surface density of an adhesive layer, characterized in that, Comprising: A dissolution reaction device and a heating device; The dissolution reaction device is used to contain a solvent; wherein, the solvent is used to dissolve the adhesive layer of the diaphragm to be tested soaked in the dissolution reaction device; The heating device is used to heat the solvent.

2. The test device for the bonding layer density according to claim 1, wherein The heating device includes an oven, and the dissolution reaction device is located inside the oven; The oven includes an exhaust component, and the exhaust component discharges the gas inside the oven to the external environment through a gas discharge pipe.

3. The test device for the adhesive layer density according to claim 1, characterized in that, Further comprising: A cleaning agent containing device, which is used to contain a cleaning agent; The cleaning agent is used to clean the impurities on the diaphragm to be tested.

4. The test device for the bonding layer density according to claim 1, characterized in that, Further comprising: A sample containing device and a lifting device; The sample containing device is installed on the lifting device and is used to place the diaphragm to be tested; The lifting device drives the sample containing device to move, so that the sample containing device is immersed in the solvent inside the dissolution reaction device.

5. The test device for the adhesive layer density according to claim 4, wherein, The sample containing device includes a sample containing box and a sample containing plate; The sample containing plate is detachably installed in the sample containing box; Openings are provided on the sample containing plate, and openings are provided on at least one surface of the sample containing box.

6. The test device for the bonding layer density according to claim 4, characterized in that, The lifting device includes: a suspension rod, a support rod, a lifting adjustment mechanism and a suspension assembly; The sample containing device is connected to the suspension rod through the suspension assembly, the suspension rod is connected to the support rod through the lifting adjustment mechanism, and the lifting adjustment mechanism controls the movement of the suspension rod relative to the support rod.

7. The test device for the adhesive layer density according to any one of claims 1-6, characterized in that, The solvent includes a dipolar aprotic compound solvent.

8. A test method for the density of the bonding layer, characterized in that, Applicable to the test device for the surface density of the adhesive layer as described in any one of claims 1-7; The method includes: Obtaining the mass of the diaphragm to be tested before soaking in the dissolution reaction device as the first mass; Soaking the diaphragm to be tested in the solvent inside the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested; Obtaining the mass of the diaphragm to be tested after dissolving the adhesive layer as the second mass; Determining the surface density of the adhesive layer of the diaphragm to be tested according to the first mass, the second mass and the area of the diaphragm to be tested.

9. The test method for the density of the bonding layer according to claim 8, characterized in that, The test device for the surface density of the adhesive layer further includes: a cleaning agent containing device, which is used to contain a cleaning agent; the cleaning agent is used to clean the impurities on the diaphragm to be tested; After soaking the diaphragm to be tested in the solvent inside the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested, further including: Putting the diaphragm to be tested after dissolving the adhesive layer into the cleaning agent containing device for cleaning.

10. The test method for the bonding layer density according to claim 8, characterized in that, The test device for the surface density of the adhesive layer further includes: a sample containing device and a lifting device; The sample containing device is installed on the lifting device and is used to place the diaphragm to be tested; the lifting device drives the sample containing device to move, so that the sample containing device is immersed in the solvent inside the dissolution reaction device; Soaking the diaphragm to be tested in the solvent inside the dissolution reaction device to dissolve the adhesive layer of the diaphragm to be tested includes: Control the lifting device to drive the sample holding device to move so that the sample holding device is immersed in the solvent in the dissolution reaction device.

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