Wettability testing device

Abstract

The utility model relates to the technical field of batteries, and discloses a wettability testing device, which comprises a fixed frame, a quality detector; the lower end of the clamp assembly is used for being connected with a to-be-tested sample; the liquid storage cup is located below the clamp assembly, and the liquid storage cup is used for containing test liquid; the heating sleeve is arranged around the liquid storage cup in the circumferential direction of the liquid storage cup; wherein the liquid storage cup is placed on the mass detector, the clamp assembly is connected with the fixing frame, and the mass detector is used for detecting the weight of test liquid; or the clamp assembly is connected with the mass detector, the liquid storage cup is placed on the fixing frame, and the mass detector is used for detecting the weight of the sample to be detected. The wettability testing device disclosed by the embodiment of the utility model not only can heat the testing liquid, but also is uniform in temperature of the testing liquid, and is beneficial to improving the testing accuracy.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a wettability testing device. Background Art

[0002] With the development of new energy technologies, the requirements for battery cell performance are becoming increasingly stringent. Increasing the electrode density is one of the fastest and most effective ways to improve battery cell performance. However, excessively high density can affect the electrode's wettability. Therefore, it is particularly important to conduct experimental tests on the wettability of various materials before production begins.

[0003] In the related art, the testing device usually includes an electrolyte tank loaded with electrolyte, and the sample to be tested is inserted into the electrolyte to test the wettability of the electrolyte on the sample to be tested. A heating plate is provided at the bottom of the electrolyte tank. The heating plate can heat the electrolyte tank to test the wettability of various materials at different temperatures. However, the temperature uniformity of each area of the electrolyte is poor, which can easily lead to errors in the test results. Utility Model Content

[0004] In view of this, the present invention provides a wettability testing device to alleviate or solve the problem of errors in test results caused by uneven temperature of the test liquid.

[0005] The utility model provides a wettability testing device, comprising: a fixed frame; a mass detector; a fixture assembly, the lower end of the fixture assembly is used to connect a sample to be tested; a liquid storage cup, the liquid storage cup is located below the fixture assembly, and the liquid storage cup is used to hold a test liquid; a heating sleeve, the heating sleeve is arranged around the liquid storage cup along the circumference of the liquid storage cup; wherein the liquid storage cup is placed on the mass detector, the fixture assembly is connected to the fixed frame, and the mass detector is used to detect the weight of the test liquid; or the fixture assembly is connected to the mass detector, the liquid storage cup is placed on the fixed frame, and the mass detector is used to detect the weight of the sample to be tested.

[0006] Beneficial Effects: By providing a heating jacket, the test liquid in the liquid storage cup can be heated to test the speed at which the test liquid infiltrates the sample to be tested at different temperatures. Compared to providing a heating structure at the bottom of the liquid storage cup, in the embodiment of the present invention, since the heating jacket surrounds the liquid storage cup along the circumference of the liquid storage cup, the heating jacket heats the test liquid from all directions along the circumference of the liquid storage cup, and each area of the test liquid is heated more evenly. Moreover, compared to providing the heating jacket below the liquid storage cup, providing the heating jacket around the circumference of the liquid storage cup brings the heating jacket closer to the liquid surface of the test liquid. In other words, the heating jacket is closer to the sample to be tested in the vertical direction, which is beneficial for directly heating the test liquid in the area where the sample to be tested is located, thereby avoiding temperature fluctuations or uneven temperature of the test liquid in the area where the sample to be tested is located, and improving test accuracy.

[0007] In an optional embodiment, the liquid storage cup is provided with a preset liquid level height, the preset liquid level height is equal to or lower than the highest point of the heating jacket, and the preset liquid level height is equal to or higher than the lowest point of the heating jacket.

[0008] Beneficial effect: The test liquid in the area where the sample to be tested is located is surrounded by the heating jacket, which is conducive to directly heating the test liquid in the area where the sample to be tested is located, so as to avoid temperature fluctuation or temperature unevenness of the test liquid in the area where the sample to be tested is located, and improve test accuracy.

[0009] In an optional embodiment, the liquid storage cup is placed on the mass detector, the heating jacket is connected to the fixing frame, and the inner circumference of the heating jacket is spaced apart from the outer circumference of the liquid storage cup.

[0010] Beneficial effects: It can ensure that the heating sleeve heats the liquid storage cup, and can also prevent the weight of the heating sleeve from being applied to the mass detector through the liquid storage cup, so that the mass detector mainly measures the weight of the liquid storage cup and the test liquid therein, and thus the mass detector is more obvious to the mass change of the test liquid, which is beneficial to improving the test accuracy, and the detection upper limit of the mass detector can be relatively reduced, thereby reducing the production cost of the mass detector.

[0011] In an optional embodiment, the wettability testing device further includes: a temperature sensor, wherein the temperature sensor is used to detect the temperature of the test liquid contained in the liquid storage cup, and the temperature sensor is movable in a vertical direction relative to the liquid storage cup.

[0012] Beneficial effect: By setting up a temperature sensor, the temperature near the liquid surface of the test liquid can be obtained in time, which is conducive to ensuring that the temperature near the liquid surface of the test liquid is maintained at the required temperature, and the test effect on the sample to be tested is more effective.

[0013] In an optional embodiment, the liquid storage cup includes: a cup body, the cup body is used to hold the test liquid, and the upper end of the cup body is provided with an opening; a sealing cover, the sealing cover is connected to the cup body, the sealing cover is used to seal the opening, the sealing cover is provided with an opening, and the clamp assembly is passed through the opening so that the lower end of the clamp assembly is located in the liquid storage cup.

[0014] Beneficial effect: The sealing cover is provided to seal the opening of the cup body, thereby preventing the test liquid from volatilizing.

[0015] In an optional embodiment, the fixture assembly includes: a winding fixture, which is used to fix the sample to be tested in a wound form on the winding fixture; and / or a stacking fixture, which is used to fix the sample to be tested.

[0016] Beneficial effect: By setting two different fixtures, a winding fixture and a stacking fixture, the wettability test device can simulate the wetting conditions of different types of battery cells. It is not only closer to the actual usage scenario, but also suitable for testing different types of battery cells. It has many application scenarios and a wide range of applicability.

[0017] In an optional embodiment, the clamp assembly further includes: a connecting member, the upper end of which is connected to the fixed frame, and the connecting member is constructed as a rigid member; wherein, when the clamp assembly includes the winding clamp, the winding clamp is connected to the connecting member; when the clamp assembly includes the lamination clamp, the lamination clamp is connected to the connecting member.

[0018] Beneficial effect: The fixture assembly and the fixing frame are rigidly connected, which can prevent the sample to be tested from sliding relative to the fixing frame, thereby preventing the shaking of the sample to be tested from causing fluctuations in the test liquid, reducing measurement errors, and improving the accuracy of the test structure.

[0019] In an optional embodiment, the winding clamp includes: a clamp body, the outer contour of which is configured as a cylinder, and the clamp body is used to fix the sample to be tested to the clamp body in a wound form; a liquid isolation membrane, which surrounds the clamp body and is used to cover at least a portion of the outer peripheral surface of the sample to be tested to separate the test liquid from the outer peripheral surface of the sample to be tested.

[0020] Beneficial effects: The liquid diaphragm is used to isolate the outer surface of the sample to be tested from the test liquid, avoiding contact between the outer surface of the sample to be tested and the test liquid. That is to say, the electrolyte mainly infiltrates the battery cell from the end of the battery cell, reducing the amount of liquid absorbed by the outermost diaphragm of the battery cell, avoiding excessive liquid absorption of the outermost diaphragm affecting the test results, and restoring the actual situation of the battery cell during infiltration to the greatest extent, which is conducive to measuring the infiltration effect of the battery cell under actual conditions.

[0021] In an optional embodiment, the clamp assembly is movable in a vertical direction relative to the fixing frame.

[0022] Beneficial Effects: During assembly of the wettability test device, the fixture assembly and the liquid storage cup can be vertically spaced relatively far apart to prevent the sample from accidentally contacting the test liquid. This prevents fluctuations in the weight of the test liquid and ensures the reliability of the test structure. Furthermore, upon completion of the test, the wettability test device does not need to be disassembled; the sample and test liquid can be separated by adjusting the vertical position of the fixture assembly. This rapid separation allows the sample to be effectively maintained in its current state, facilitating subsequent measurement of the wetted area on the sample and improving test accuracy.

[0023] In an optional embodiment, the liquid storage cup is placed on the mass detector, and the fixing frame includes: a base, on which the mass detector is placed; a frame, which is detachably placed on the base, and the clamp assembly is connected to the frame. The frame and the base enclose a storage space, and the mass detector, the clamp assembly and the liquid storage cup are located in the storage space.

[0024] Beneficial effect: The fixing frame isolates the containing space from the outside space, preventing the fluctuation of the outside space from affecting the gas state in the containing space. The fixing frame and the sealing cover form a double sealing effect, which more effectively prevents the influence of air fluctuations outside the containing space on the test structure and improves the accuracy of the test. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 This is a structural schematic diagram of a wettability testing device according to an embodiment of the present invention;

[0027] Figure 2 This is a second structural diagram of the wettability testing device according to an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the cooperation between the winding fixture and the sample to be tested of the wettability testing device according to an embodiment of the present invention;

[0029] Figure 4Schematic diagram of the cooperation between the laminated fixture and the sample to be tested of the wettability testing device according to an embodiment of the present invention.

[0030] Description of reference numerals:

[0031] 1. Wettability test device; 2. Sample to be tested; 100. Fixing frame; 101. Accommodating space; 110. Base; 120. Frame; 200. Mass detector; 300. Clamp assembly; 310. Connector; 320. Winding clamp; 321. Clamp body; 322. Liquid barrier membrane; 331. Clamping piece; 400. Liquid storage cup; 401. Test liquid; 410. Cup body; 411. Opening; 420. Sealing cover; 500. Heating jacket; 600. Temperature sensor. DETAILED DESCRIPTION

[0032] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are 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 those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0034] In the description of the present invention, the meaning of "plurality" is two or more. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0035] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0036] The following combination Figures 1-4 Shown, an embodiment of the present utility model is described.

[0037] According to an embodiment of the present invention, a wettability testing device 1 is provided. The wettability testing device 1 includes a fixing frame 100 , a mass detector 200 , a fixture assembly 300 , a liquid storage cup 400 and a heating jacket 500 .

[0038] The mass detector 200 may be connected to the fixed frame 100 or not. The mass detector 200 may be a device capable of measuring the mass of an object, such as an electronic balance. The lower end of the fixture assembly 300 is connected to the sample 2 to be tested. The liquid reservoir 400 is located below the fixture assembly 300. The liquid reservoir 400 contains a test liquid 401, and the lower end of the sample 2 to be tested is inserted into the test liquid 401. The heating jacket 500 surrounds the liquid reservoir 400 along its circumference.

[0039] In one specific embodiment, the liquid storage cup 400 is placed on the mass detector 200, the clamp assembly 300 is connected to the fixed frame 100, and the mass detector 200 is used to detect the weight of the test liquid 401; in another specific embodiment, the clamp assembly 300 is connected to the mass detector 200, the clamp assembly 300 is connected to the lower surface of the mass detector 200, the liquid storage cup 400 can be placed on the fixed frame 100, and the mass detector 200 is used to detect the weight of the sample 2 to be tested.

[0040] After the sample 2 is immersed in the liquid surface of the test liquid 401 , the test liquid 401 will continue to penetrate into the sample 2 . The time starts from the time when the sample 2 is immersed in the liquid surface of the test liquid 401 , and the mass detector 200 automatically weighs.

[0041] In the embodiment where the liquid storage cup 400 is placed on the mass detector 200, the mass detector 200 records the sum of the initial masses of the liquid storage cup 400 and the test liquid 401, and the sum of the masses of the liquid storage cup 400 and the test liquid 401 at time t is m. t , subtract the two to obtain the total weight Δm of the test sample 2 absorbed by the test liquid 401;

[0042] In the embodiment where the clamp assembly 300 is connected to the lower surface of the mass detector 200, the mass detector 200 records the sum of the initial masses of the clamp assembly 300 and the sample 2 to be tested, and stores the sum of the masses of the clamp assembly 300 and the sample 2 to be tested m at time t. t , subtracting the two to obtain the total weight Δm of the test liquid 401 absorbed by the sample 2 to be tested.

[0043] In the two aforementioned embodiments, after a period of testing, the wettability testing apparatus 1 obtains a function of the liquid absorption weight versus time of the sample 2, Δm-t. From this, the liquid absorption rate V = Δm / t of the sample 2 at a preset temperature and the saturated wetting time can be deduced. The sample 2 can then be separated from the wettability testing apparatus 1, and the length L of the sample 2 wetted can be measured to obtain the function of the liquid absorption size versus time, Lt, of the sample 2.

[0044] By providing the heating jacket 500 , the test liquid 401 in the liquid storage cup 400 can be heated to test the speed at which the test liquid 401 infiltrates the test sample 2 at different temperatures. The test temperature is more in line with actual application conditions.

[0045] Compared with the prior art in which a heating structure is provided at the bottom of the liquid storage cup, in the embodiment of the present invention, since the heating sleeve 500 surrounds the liquid storage cup 400 along the circumference of the liquid storage cup 400, the heating sleeve 500 heats the test liquid 401 from all directions along the circumference of the liquid storage cup 400, and each area of the test liquid 401 is heated more evenly.

[0046] Moreover, the heating jacket 500 is closer to the liquid surface of the test liquid 401, that is, the heating jacket 500 is closer to the sample 2 to be tested in the vertical direction, which is conducive to directly heating the test liquid 401 in the area where the sample 2 to be tested is located, so as to avoid temperature fluctuations or uneven temperature of the test liquid 401 in the area where the sample 2 to be tested is located, thereby improving the test accuracy.

[0047] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the liquid storage cup 400 is provided with a preset liquid level height, which is located between the two ends of the heating sleeve 500 in the axial direction of the heating sleeve 500, that is, the preset liquid level height is level with or lower than the upper side of the heating sleeve 500, and the preset liquid level height is level with or higher than the lower side of the heating sleeve 500.

[0048] When the test liquid 401 is poured into the liquid storage cup 400 , the liquid level of the test liquid 401 is maintained at a preset liquid level so that the liquid level of the test liquid 401 is located between the two ends of the heating sleeve 500 in the axial direction of the heating sleeve 500 .

[0049] In this way, generally speaking, the sample to be tested 2 is close to the liquid surface of the test liquid 401, and the test liquid 401 in the area where the sample to be tested 2 is located can be surrounded by the heating sleeve 500, which is conducive to directly heating the test liquid 401 in the area where the sample to be tested 2 is located, so as to avoid temperature fluctuations or uneven temperature of the test liquid 401 in the area where the sample to be tested 2 is located, thereby improving the test accuracy.

[0050] like Figure 1 As shown, in the technical solution of this embodiment, when the liquid storage cup 400 is placed on the mass detector 200, the heating sleeve 500 is connected to the fixing frame 100, and the inner circumferential surface of the heating sleeve 500 is spaced apart from the outer circumferential surface of the liquid storage cup 400, that is, the inner circumferential surface of the heating sleeve 500 does not contact the outer circumferential surface of the liquid storage cup 400, and no other structure is placed between the inner circumferential surface of the heating sleeve 500 and the outer circumferential surface of the liquid storage cup 400.

[0051] The distance between the heating jacket 500 and the liquid storage cup 400 is no more than 1 mm. Of course, it is understandable that when the mass detector 200 is connected to the fixture assembly 300, the heating jacket 500 can be connected to the fixing frame 100, and the heating jacket 500 can also be connected to the liquid storage cup 400.

[0052] In this way, it can ensure that the heating sleeve 500 heats the liquid storage cup 400, and can also prevent the mass of the heating sleeve 500 from being applied to the mass detector 200 through the liquid storage cup 400, so that the mass detector 200 mainly measures the mass of the liquid storage cup 400 and the test liquid 401 therein, and thus the mass detector 200 is more obvious in detecting the mass change of the test liquid 401, which is beneficial to improving the test accuracy. Moreover, since the mass detector 200 does not need to detect the mass of the heating sleeve 500, the detection upper limit of the mass detector 200 can be relatively reduced, thereby reducing the production cost of the mass detector 200.

[0053] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the wettability testing device 1 further includes a temperature sensor 600, which is used to detect the temperature of the test liquid 401 contained in the liquid storage cup 400. The temperature sensor 600 is movable in the vertical direction relative to the liquid storage cup 400. The temperature sensor 600 is located in the test liquid 401 and is adjacent to the liquid surface of the test liquid 401. It should be noted that the temperature sensor 600 being adjacent to the liquid surface of the test liquid 401 means that the distance between the temperature sensor 600 and the liquid surface of the test liquid 401 is less than the distance between the temperature sensor 600 and the liquid bottom of the test liquid 401.

[0054] For example, in some embodiments, the temperature sensor 600 can be connected to the fixed frame 100 through a motor and a screw structure, and the motor drives the screw structure to rotate to enable the temperature sensor 600 to move in the vertical direction relative to the liquid storage cup 400; in other embodiments, the temperature sensor 600 can be connected to the fixed frame 100 through a motor and a screw structure, and the motor drives the screw structure to rotate to expand or contract the wire harness wound on the wire harness, and the temperature sensor 600 is connected to the wire harness on the wire harness, thereby enabling the temperature sensor 600 to move in the vertical direction relative to the liquid storage cup 400.

[0055] Of course, those skilled in the art will understand that the method of realizing the vertical movement of the temperature sensor 600 relative to the liquid storage cup 400 is not limited to the above two methods, and other settings that can realize the vertical movement of the temperature sensor 600 relative to the liquid storage cup 400 are within the scope of protection of the present invention.

[0056] By providing the temperature sensor 600 , the temperature near the liquid surface of the test liquid 401 can be obtained in a timely manner, which helps to ensure that the temperature near the liquid surface of the test liquid 401 is maintained at the required temperature, and the test effect on the sample 2 to be tested is more effective.

[0057] In addition, the liquid level of the test liquid 401 may change during the test process. For example, when the test liquid 401 infiltrates more into the sample 2 to be tested, the liquid level of the test liquid 401 may decrease, or the amount of test liquid 401 injected into the liquid storage cup 400 each time may be different. In order to test whether the amount of the test liquid 401 affects the infiltration effect, the temperature sensor 600 is movable in the vertical direction relative to the liquid storage cup 400, and the height of the temperature sensor 600 can be changed in time according to the liquid level of the test liquid 401 to ensure that the temperature sensor 600 always detects the temperature of the liquid surface of the test liquid 401, thereby ensuring that the temperature of the test liquid 401 around the sample 2 to be tested is always maintained at the preset test temperature, thereby ensuring the reliability of the test results.

[0058] like Figure 1 and 2 As shown, in the technical solution of this embodiment, the liquid storage cup 400 includes a cup body 410 and a sealing cover 420. The cup body 410 is used to hold the test liquid 401. The inner diameter of the cup body 410 can be 6 cm to 10 cm. For example, the inner diameter of the cup body 410 can be 6 cm, 6.5 cm, 7 cm, 7.5 cm, 8 cm, 8.5 cm, 9 cm, 9.5 cm, or 10 cm. The upper end of the cup body 410 is provided with an opening 411. The sealing cover 420 is connected to the cup body 410 and covers the opening 411. The sealing cover 420 has an opening, and the clamp assembly 300 is inserted into the opening so that the lower end of the clamp assembly 300 is located within the liquid storage cup 400.

[0059] By setting a sealing cover 420 to seal the opening 411 of the cup body 410, the volatilization rate of the test liquid 401 in the liquid storage cup 400 is reduced, and the influence of the volatilization of the test liquid 401 on the test results is reduced, wherein the diameter of the sealing cover 420 is larger than the diameter of the opening 411, and the opening of the sealing cover 420 and the clamp assembly 300 can be clearance-fitted to prevent the vertical movement of the clamp assembly 300 from affecting the measurement results of the mass detector 200.

[0060] like Figures 1-4 As shown, in the technical solution of this embodiment, the clamp assembly 300 includes a winding clamp 320, which is used to fix the sample to be tested in a wound form on the winding clamp, or the clamp assembly 300 includes a stacking clamp, which is used to fix the sample to be tested 2; or the clamp assembly 300 includes both the winding clamp 320 and the stacking clamp, the winding clamp is used to fix the sample to be tested in a wound form on the winding clamp, and the stacking clamp is used to fix the sample to be tested 2.

[0061] The winding fixture 320 may include a cylindrical fixture body 321, which may be a polytetrafluoroethylene cylinder. The outer diameter of the fixture body 321 may be 20 mm, and the axial length of the fixture body 321 may be 60 mm. The lamination fixture may include a clamping member and two clamping plates 331, which may be polytetrafluoroethylene plates. The clamping plates 331 may have dimensions of 60 mm * 60 mm * 5 mm, which facilitate maintaining the sample 2 in a vertical position, preventing bending of the sample 2, and facilitating measurement. The clamping member may be a device capable of clamping, such as a clip.

[0062] For example, the sample to be tested 2 may be a battery cell, the test sample may be an electrolyte, and the sample to be tested 2 may be simulated into the shape of a wound battery cell or a laminated battery cell to simulate the wetting condition of the wound battery cell or the laminated battery cell.

[0063] The following is combined with Figure 3 , the following example describes the steps for simulating the wetting of wound cells:

[0064] First, cut the electrode and diaphragm into squares, where the size of the square can be 5cm*60cm;

[0065] Then, stack the negative electrode sheet, separator, positive electrode sheet, and separator in the order of stacking to form a battery cell. Use electrolyte-resistant tape to secure one end of the battery cell to the fixture body 321. Apply a certain amount of tension to tighten all the electrode sheets and separators and gradually roll them onto the fixture body 321. Finally, use electrolyte-resistant tape to secure the other end of the battery cell.

[0066] Finally, a circle of tape is applied to the outermost diaphragm to expose the axial ends of the battery cell, thus restoring the actual situation of the wound battery cell during infiltration to the greatest extent possible. That is, the electrolyte can only infiltrate through the axial end faces of the wound battery cell, reducing the amount of liquid absorbed by the outermost diaphragm and avoiding excessive liquid absorption by the outermost diaphragm that affects the test results.

[0067] The following is combined with Figure 4 , take an example to describe the steps of simulating the wetting of a stacked cell:

[0068] First, cut the diaphragm and the electrode into squares respectively, wherein the size of the square can be 5cm*5cm;

[0069] Then, they are stacked on a clamping sheet 331 in the order of diaphragm-negative electrode sheet-diaphragm-positive electrode sheet.

[0070] Next, after stacking 10 positive electrode sheets, use a clamp to clamp the stacked battery cell and the clamping sheet 331, and use electrolyte-resistant tape to fix the four edges of the battery cell to the clamping sheet 331;

[0071] Finally, release the clamping piece and place another clamping piece 331 on the battery cell. The two clamping pieces 331 are located on opposite sides of the battery cell in the thickness direction. Use the clamping piece to apply a certain pre-tightening force to clamp the two clamping pieces 331 to the battery cell to ensure that the battery cell does not slip or become loose.

[0072] By setting two different fixtures, the winding fixture 320 and the stacking fixture, the wettability testing device 1 can simulate the wettability of different types of battery cells. It is not only closer to the actual usage scenario, but also suitable for testing different types of battery cells. It has many application scenarios and a wide range of applications.

[0073] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the clamp assembly 300 further includes a connector 310, which is a rigid member. When the clamp assembly 300 includes a winding clamp 320, the winding clamp 320 is connected to the connector 310; when the clamp assembly 300 includes a lamination clamp, the lamination clamp is connected to the connector 310; when the clamp assembly 300 includes both the winding clamp 320 and the lamination clamp, either the winding clamp 320 or the lamination clamp is connected to the connector 310.

[0074] Among them, the connecting member 310 can be made of metal material, for example, the material of the connecting member 310 can be stainless steel, the diameter of the connecting member 310 can be not less than 2 mm, the diameter of the connecting member 310 can be 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, the length of the connecting member 310 can be 90 mm to 110 mm, and the length of the connecting member 310 can be 90 mm, 95 mm, 100 mm, 105 mm or 110 mm.

[0075] In this way, the clamp assembly 300 and the fixing frame 100 are rigidly connected, which can prevent the sample 2 to be tested from sliding relative to the fixing frame 100, thereby preventing the shaking of the sample 2 to be tested from causing fluctuations in the test liquid 401, reducing measurement errors, and improving the accuracy of the test structure.

[0076] like Figure 3 As shown, in the technical solution of this embodiment, the winding fixture 320 includes a fixture body 321 and a liquid barrier film 322. The outer contour of the fixture body 321 is cylindrical. The fixture body 321 is used to fix the sample 2 to be tested in a wound form on the fixture body 321. The liquid barrier film 322 is used to cover at least a portion of the outer circumference of the sample 2 to be tested. The liquid barrier film 322 is made of an electrolyte-resistant material and can be an electrolyte-resistant tape.

[0077] When the sample 2 to be tested is a battery cell and the test liquid 401 is an electrolyte, the liquid separator 322 is used to isolate the outer peripheral surface of the sample 2 to be tested from the test liquid 401, preventing the outer peripheral surface of the sample 2 to be tested from contacting the test liquid 401. That is, the electrolyte mainly infiltrates the wound battery cell from the end of the wound battery cell, reducing the amount of liquid absorbed by the outermost separator of the wound battery cell, avoiding excessive liquid absorption by the outermost separator affecting the test results, and restoring the actual situation of the wound battery cell during infiltration to the greatest extent, which is conducive to measuring the infiltration effect of the wound battery cell under actual conditions.

[0078] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, the clamp assembly 300 is movable in the vertical direction relative to the fixing frame 100.

[0079] For example, the clamp assembly 300 and the fixing frame 100 may be connected via a screw assembly, and the clamp assembly 300 may be controlled to move in the vertical direction by the rotation of the screw assembly; or the clamp assembly 300 and the fixing frame 100 may be threadedly matched, and the clamp assembly 300 may be controlled to move in the vertical direction by the relative rotation between the clamp assembly 300 and the fixing frame 100; or the fixing frame 100 may be provided with a snap-fit structure, and the clamp assembly 300 may be controlled to move in the vertical direction by adjusting the opening and closing of the snap-fit structure.

[0080] During the assembly of the wettability testing device 1, the vertical distance between the fixture assembly 300 and the liquid storage cup 400 can be relatively far to prevent the sample 2 to be tested from accidentally contacting the test liquid 401. The quality of the test liquid 401 will not fluctuate, thereby ensuring the reliability of the test results of the quality detector 200.

[0081] Moreover, when the test is completed, there is no need to disassemble the wettability testing device 1. By adjusting the position of the clamp assembly 300 in the vertical direction, the sample to be tested 2 and the test liquid 401 can be separated. The separation speed between the sample to be tested 2 and the test liquid 401 is fast, and the sample to be tested 2 can be effectively maintained in the current state, which is convenient for subsequent measurement of the size of the wetted surface on the sample to be tested 2, thereby improving the accuracy of the detection.

[0082] like Figure 1 and Figure 2 As shown, in the technical solution of this embodiment, when the liquid storage cup 400 is placed on the mass detector 200, the fixing frame 100 includes a base 110 and a frame 120. The mass detector 200 is placed on the base 110, and the frame 120 is detachably placed on the base 110. The clamp assembly 300 is connected to the frame 120. The frame 120 and the base 110 together define a receiving space 101. The mass detector 200, the clamp assembly 300, and the liquid storage cup 400 are located in the receiving space 101.

[0083] For example, the containment space 101 can be a sealed space or a semi-enclosed space, and the frame 120 can be made of a transparent material to facilitate observation by the operator of the conditions within the containment space 101. In this way, the fixing frame 100 isolates the containment space 101 from the outside world, preventing fluctuations in the outside world from affecting the gas state in the containment space 101. The fixing frame 100 and the sealing cover 420 form a double seal, more effectively preventing air fluctuations outside the containment space 101 from affecting the test structure, thereby improving test accuracy.

[0084] The following example describes the steps of using the wettability testing device 1:

[0085] First, add 50 mL of the test liquid 401 into the cup 410 and transfer the cup 410 to the mass detector 200;

[0086] Then, one of the winding fixture 320 and the lamination fixture is connected to the connector 310 , and the connector 310 is passed through the opening of the sealing cover 420 , and the sample 2 to be tested is placed in the cup body 410 , and the sealing cover 420 covers the opening 411 of the cup body 410 ;

[0087] Next, the connector 310 is fixed to the fixing frame 100 , and the position of the heating jacket 500 is adjusted so that the heating jacket 500 surrounds the surface of the test liquid 401 along the circumference of the cup body 410 ;

[0088] Finally, the heating jacket 500 is started until the test liquid 401 reaches the preset temperature and keeps warm, and the height of the fixture assembly 300 is adjusted until the bottom of the test sample 2 is immersed 3mm to 8mm below the liquid surface of the test liquid 401, for example, 3mm, 4mm, 5mm, 6mm, 7mm and 8mm.

[0089] The time starts from the moment the sample 2 is immersed in the liquid surface of the test liquid 401. The mass detector 200 automatically weighs and records the sum of the initial masses of the liquid storage cup 400 and the test liquid 401, as well as the sum of the masses at time t m t , the total weight Δm of the test liquid 401 absorbed by the test sample 2 is obtained by subtracting the two. After testing for a period of time, the relationship function of the liquid absorption weight of the test sample 2 with time Δm-t is obtained. From this, the liquid absorption rate V = Δm / t of the test sample 2 at the preset temperature and the saturated immersion time can be deduced.

[0090] The following examples describe the test results of the wettability testing device 1 in some embodiments:

[0091] In the first embodiment, negative and positive electrode sheets are prepared. The ratio of graphite, carbon black, CMC (Carboxymethyl Cellulose), and SBR (Polymerized Styrene Butadiene Rubber) in the negative electrode sheet is 94:2:1.2:1.8, and the double-sided density of the negative electrode sheet is 160g / m 2 , compacted density is 1.59g / m 3 The ratio of lithium iron phosphate, carbon black, carbon nanotubes, and PVDF (polyvinylidene difluoride) in the positive electrode is 96:1:0.5:3.5, and the double-sided density of the positive electrode is 380g / m 2 , compacted density is 2.44g / m 3 .

[0092] The negative electrode sheet, positive electrode sheet, and 6μm thick PE (polyethylene) separator were cut into 5cm*5cm squares and stacked in the order of separator-negative electrode sheet-separator-positive electrode sheet... until 10 positive electrode sheets were stacked. The stack was connected to a stacking fixture and immersed 5mm in an electrolyte with a lithium hexafluorophosphate concentration of 1mol / L and a ratio of EC (ethylene carbonate):DEC (diethyl carbonate):EMC (ethyl methyl carbonate) of 1:1:1. Tests were conducted at 25°C and 45°C. The test results are as follows:

[0093]

[0094] From the above results, it can be seen that increasing the immersion temperature can effectively increase the liquid absorption rate of the electrode core and achieve saturated immersion in advance.

[0095] In the second embodiment, a first negative electrode sheet, a second negative electrode sheet, a first positive electrode sheet, and a second positive electrode sheet are prepared. The ratio of graphite, carbon black, CMC, and SBR in the first negative electrode sheet and the second negative electrode sheet is 94:2:1.2:1.8, and the double-sided density of the first negative electrode sheet is 160g / m 2 , compacted density is 1.59g / m 3 The double-sided density of the second negative electrode sheet is 160g / m 2 , compacted density is 1.67g / m 3 The ratio of lithium iron phosphate, carbon black, carbon nanotubes, and PVDF in the first and second positive electrode sheets is 96:1:0.5:3.5, and the double-sided density of the first positive electrode sheet is 380g / m 2 , compacted density is 2.44g / m 3 The double-sided density of the second positive electrode sheet is 380g / m 2 , compacted density is 2.49g / m 3 .

[0096] The first negative electrode sheet, the second negative electrode sheet, the first positive electrode sheet, the second positive electrode sheet, and a 6 μm thick PE separator were cut into 5 cm * 60 cm strips and stacked in the order of first negative electrode sheet - separator - first positive electrode sheet - separator to form a first test sample. The second negative electrode sheet - separator - second positive electrode sheet - separator were stacked in the order of second negative electrode sheet - separator to form a second test sample. The strips were connected to the winding fixture 320 in this order and immersed in the electrolyte for 5 mm. The concentration of lithium hexafluorophosphate in the electrolyte was 1 mol / L, and the ratio of EC:DEC:EMC was 1:1:1. The test was performed at 45°C. The test results are as follows:

[0097]

[0098] From the above results, it can be seen that increasing the compaction density of the electrode reduces the liquid absorption rate of the electrode core and prolongs the time required to reach saturated infiltration.

[0099] In the third embodiment, a first negative electrode sheet, a second negative electrode sheet, a first positive electrode sheet, and a second positive electrode sheet are prepared. The ratio of graphite, carbon black, CMC, and SBR in the first negative electrode sheet and the second negative electrode sheet is 94:2:1.2:1.8, and the double-sided density of the first negative electrode sheet is 160g / m 2 , compacted density is 1.59g / m 3 The double-sided density of the second negative electrode sheet is 180g / m 2 , compacted density is 1.59g / m 3 The ratio of lithium iron phosphate, carbon black, carbon nanotubes, and PVDF in the first and second positive electrode sheets is 96:1:0.5:3.5, and the double-sided density of the first positive electrode sheet is 420g / m 2 , compacted density is 2.44g / m 3 The double-sided density of the second positive electrode sheet is 380g / m 2 , compacted density is 2.49g / m 3 .

[0100] The first negative electrode sheet, the second negative electrode sheet, the first positive electrode sheet, the second positive electrode sheet, and a 6 μm thick PE separator were cut into 5 cm * 60 cm strips, and stacked in the order of first negative electrode sheet - separator - first positive electrode sheet - separator to form a first test sample. The second negative electrode sheet - separator - second positive electrode sheet - separator were stacked in the order of second negative electrode sheet - separator to form a second test sample. The samples were connected to the winding fixture 320 in this order and immersed in the electrolyte for 5 mm. The concentration of lithium hexafluorophosphate in the electrolyte was 1 mol / L, and the ratio of EC:DEC:EMC was 1:1:1. The samples were tested at 45°C. The test results are as follows:

[0101]

[0102] From the above results, it can be seen that increasing the surface density of the electrode reduces the liquid absorption rate of the electrode core and prolongs the time required to reach saturated wetting.

[0103] Where specific experimental steps or conditions are not specified in the above examples, the experiments may be performed according to the conventional experimental steps or conditions described in the literature in the art.

[0104] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A wettability testing device, characterized in that: include: Fixed frame (100); a mass detector (200); A clamp assembly (300), wherein the lower end of the clamp assembly (300) is used to connect to the sample to be tested (2); a liquid storage cup (400), the liquid storage cup (400) being located below the fixture assembly (300), and the liquid storage cup (400) being used to hold a test liquid (401); a heating sleeve (500), the heating sleeve (500) being arranged around the liquid storage cup (400) along the circumference of the liquid storage cup (400); wherein the liquid storage cup (400) is placed on the mass detector (200), the clamp assembly (300) is connected to the fixing frame (100), and the mass detector (200) is used to detect the weight of the test liquid (401); or The clamp assembly (300) is connected to the mass detector (200), the liquid storage cup (400) is placed on the fixing frame (100), and the mass detector (200) is used to detect the weight of the sample to be tested (2).

2. The wettability testing device according to claim 1, characterized in that: The liquid storage cup (400) is provided with a preset liquid level height, the preset liquid level height being equal to or lower than the highest point of the heating jacket (500), and the preset liquid level height being equal to or higher than the lowest point of the heating jacket (500).

3. The wettability testing device according to claim 1, wherein: The liquid storage cup (400) is placed on the mass detector (200), the heating sleeve (500) is connected to the fixing frame (100), and the inner circumference of the heating sleeve (500) is spaced apart from the outer circumference of the liquid storage cup (400).

4. The wettability testing device according to any one of claims 1 to 3, characterized in that: Also includes: A temperature sensor (600) is used to detect the temperature of the test liquid (401) contained in the liquid storage cup (400), and the temperature sensor (600) is movable in a vertical direction relative to the liquid storage cup (400).

5. The wettability testing device according to any one of claims 1 to 3, characterized in that: The liquid storage cup (400) comprises: a cup body (410), the cup body (410) being used to hold the test liquid (401), and an opening (411) being provided at an upper end of the cup body (410); A sealing cover (420) is connected to the cup body (410), and the sealing cover (420) is used to seal the opening (411). The sealing cover (420) is provided with an opening, and the clamp assembly (300) is passed through the opening so that the lower end of the clamp assembly (300) is located in the liquid storage cup (400).

6. The wettability testing device according to any one of claims 1 to 3, characterized in that: The clamp assembly (300) comprises: A winding fixture (320), the winding fixture (320) is used to fix the sample to be tested (2) on the winding fixture (320) in a winding form; and / or A lamination fixture is used to fix the sample to be tested (2).

7. The wettability testing device according to claim 6, characterized in that: The clamp assembly (300) further includes: A connecting member (310), the upper end of which is connected to the fixing frame (100), and the connecting member (310) is a rigid member; Wherein, when the clamp assembly (300) includes the winding clamp (320), the winding clamp (320) is connected to the connecting member (310); When the clamp assembly (300) includes the lamination clamp, the lamination clamp is connected to the connecting member (310).

8. The wettability testing device according to claim 6, characterized in that: The winding fixture (320) comprises: A clamp body (321), wherein the outer contour of the clamp body (321) is cylindrical, and the clamp body (321) is used to fix the sample to be tested (2) on the clamp body (321) in a coiled form; A liquid separation membrane (322), the liquid separation membrane (322) surrounds the clamp body (321), and the liquid separation membrane (322) is used to cover at least a portion of the outer peripheral surface of the sample to be tested (2) to separate the test liquid (401) from the outer peripheral surface of the sample to be tested (2).

9. The wettability testing device according to any one of claims 1 to 3, characterized in that: The clamp assembly (300) is movable in a vertical direction relative to the fixing frame (100).

10. The wettability testing device according to any one of claims 1 to 3, characterized in that: The liquid storage cup (400) is placed on the mass detector (200), and the fixing frame (100) includes: a base (110), wherein the mass detector (200) is placed on the base (110); A frame (120) is provided, wherein the frame (120) is detachably placed on the base (110), the clamp assembly (300) is connected to the frame (120), the frame (120) and the base (110) enclose a receiving space (101), and the mass detector (200), the clamp assembly (300) and the liquid storage cup (400) are located in the receiving space (101).

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