A device for detecting the air permeability of a lithium battery separator sample

Abstract

This application relates to the field of separator production testing technology, and more specifically to a device for testing the air permeability of lithium battery separator samples. The device includes a testing platform, a sample delivery mechanism, and a testing mechanism. The sample delivery mechanism is disposed on the testing platform and includes a sample delivery drive component, a transmission roller, and a driven roller. The output end of the sample delivery drive component is connected to the transmission roller to drive its rotation. The driven roller and the transmission roller are arranged opposite each other along a first direction, and the driven roller and the transmission roller cooperate to form a clamping gap for clamping the separator sample and conveying the separator sample along a second direction. The testing mechanism is disposed on the testing platform and is located on one side of the sample delivery mechanism along the second direction. The testing mechanism is used to test the air permeability of the separator sample. The first direction and the second direction are perpendicular to each other. This application has the advantages of simple structure, flexible operation, and multi-dimensional measurement capabilities, enabling it to complete air permeability tests of separators in different dimensions, thereby improving the accuracy of the consistency test of separator air permeability.

Description

Technical Field

[0001] This application relates to the field of membrane production testing technology, and more specifically to a device for testing the permeability of lithium battery membrane samples. Background Technology

[0002] In lithium battery manufacturing, the separator is a core component, and its permeability directly determines the battery's ion conduction efficiency, charge-discharge performance, and safety stability. Insufficient permeability can hinder ion migration, affecting the battery's rate performance; uneven permeability can easily lead to localized current concentration, increasing the risk of thermal runaway. Therefore, high-precision and high-efficiency permeability testing of lithium battery separators is a crucial step in ensuring the quality of lithium battery products.

[0003] Currently, permeability testing devices for lithium-ion battery separators have been preliminarily applied. Most mainstream devices are equipped with automatic unwinding and rewinding devices, and a testing mechanism positioned between them. Through a continuous process of unwinding-conveying-testing-rewinding, batch testing of rolled separator samples is achieved, improving testing efficiency to some extent. However, these devices can only test the permeability along the length of the rolled separator sample, resulting in a single testing dimension and failing to meet the requirements for permeability testing along the width of the separator. As the lithium-ion battery industry demands increasingly stringent requirements for separator consistency, testing permeability along only the length direction is insufficient. Therefore, there is an urgent need for a device that can also perform multi-dimensional permeability testing. Utility Model Content

[0004] This application provides a device for testing the air permeability of lithium battery separator samples, which can at least partially solve or improve the above-mentioned technical problems.

[0005] This application provides a device for testing the air permeability of lithium battery separator samples, comprising:

[0006] Test platform;

[0007] A sample delivery mechanism is disposed on the test platform. The sample delivery mechanism includes a sample delivery drive assembly, a drive roller, and a driven roller. The output end of the sample delivery drive assembly is connected to the drive roller to drive its rotation. The driven roller is arranged opposite to the drive roller along a first direction, and the driven roller cooperates with the drive roller to form a clamping gap for clamping the diaphragm sample and conveying the diaphragm sample along a second direction.

[0008] The testing mechanism is disposed on the testing platform and is located on one side of the sample delivery mechanism along the second direction; the testing mechanism is used to test the air permeability of the diaphragm sample.

[0009] Wherein, the first direction and the second direction are perpendicular to each other.

[0010] In some optional embodiments, the air permeability testing device further includes a lifting mechanism connected to the sample delivery drive assembly for driving the sample delivery drive assembly to move along the first direction, thereby moving the transmission roller closer to or away from the driven roller to adjust the size of the clamping gap, thereby clamping or releasing the diaphragm sample.

[0011] In some optional embodiments, the lifting mechanism includes a lifting drive assembly and a bracket, the bracket being connected to the output end of the lifting drive assembly, the sample delivery drive assembly being disposed on the bracket, and the lifting drive assembly being used to drive the bracket to move along the first direction.

[0012] In some alternative embodiments, the lifting drive assembly includes a linear cylinder or a linear motor.

[0013] In some alternative embodiments, the sample delivery drive assembly includes a stepper motor.

[0014] In some optional embodiments, the testing mechanism includes a first test clamp, a second test clamp, a test drive assembly, a gas delivery assembly, and a test assembly. The first test clamp and the second test clamp are arranged sequentially along the first direction for sealing and clamping the diaphragm sample. The gas delivery assembly is disposed within the first test clamp for delivering gas at a constant pressure to the diaphragm sample. The test assembly is disposed within the second test clamp for detecting the gas passing through the diaphragm sample. The test drive assembly is connected to the first test clamp and drives the first test clamp to move closer to or away from the second test clamp along the first direction.

[0015] In some optional embodiments, the first test clamp has a first cavity and the second test clamp has a second cavity, and the orthographic projections of the first cavity and the second cavity in the first direction coincide.

[0016] In some optional embodiments, the test platform is provided with a first mounting cavity, and the second test chuck is disposed in the first mounting cavity, so that the central axis of the driven roller is flush with the end face of the second test chuck facing the first test chuck.

[0017] In some optional embodiments, the test platform is provided with a second mounting cavity, the bottom of the second mounting cavity is provided with a bearing seat, and the two ends of the driven roller are rotatably disposed in the bearing seat through bearings; the second mounting cavity and the first mounting cavity are flush with each other in the first direction.

[0018] In some optional embodiments, the air permeability testing device further includes a display component and a controller. The controller is connected to the sample delivery mechanism and is used to trigger the sample delivery mechanism to start. The controller is also connected to the testing mechanism and is used to trigger the testing mechanism to start and collect the air permeability value of the diaphragm sample. The display component is connected to the controller and is used to display the air permeability value measured by the testing mechanism.

[0019] The air permeability testing device for lithium battery separator samples according to this embodiment has the advantages of simple structure, flexible operation, and multi-dimensional measurement. It includes a testing mechanism and a conveying mechanism. The testing mechanism clamps and tests the air permeability of the separator sample. The separator sample is clamped and fixed by the cooperation of the testing mechanism and the conveying mechanism, and the separator sample is conveyed by their cooperation. This allows the testing mechanism to obtain the air permeability value at different positions of the separator sample in the conveying direction. Different separator samples can be prepared according to requirements to complete the air permeability test of the separator in different dimensions, thereby improving the detection accuracy of the air permeability consistency of the separator. Attached Figure Description

[0020] Figure 1 This is an axonometric schematic diagram of the structure of a device for detecting the air permeability of a lithium battery separator sample in one embodiment.

[0021] Figure 2 This is a left view of the structure of a device for detecting the air permeability of a lithium battery separator sample in one embodiment.

[0022] Figure 3 This is a front view of the structure of a device for detecting the air permeability of a lithium battery separator sample in one embodiment;

[0023] Figure 4 This is a schematic diagram of the structure of the first test clamp in one embodiment;

[0024] Figure 5 This is a schematic diagram of the structure of the second test clamp in one embodiment;

[0025] Figure 6 This is a schematic diagram of the control process of the air permeability testing device for a lithium battery separator sample in one embodiment.

[0026] Wherein: 100, test platform; 110, first mounting cavity; 120, second mounting cavity; 130, bearing seat; 200, sample feeding mechanism; 210, sample feeding drive assembly; 220, transmission roller; 230, driven roller; 240, clamping gap; 300, test mechanism; 310, first test chuck; 311, first cavity; 320, second test chuck; 321, second cavity; 330, test drive assembly; 340, air supply assembly; 350, test assembly; 400, lifting mechanism; 410, lifting drive assembly; 420, bracket; 500, mounting frame; 600, display assembly; 700, controller;

[0027] F1, first direction; F2, second direction. Detailed Implementation

[0028] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0029] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0030] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0031] The separator is one of the key components of a lithium battery, and its performance directly determines the battery's safety, cycle life, and rate performance. The separator acts as a physical barrier and ion channel between the positive and negative electrodes, facilitating ion transport between them. Therefore, the separator must possess excellent ion conductivity, and its internal micropores must provide a smooth path for lithium ion migration. The core indicator of this capability is the separator's permeability. Insufficient permeability increases resistance to lithium ion migration, resulting in slower charging speeds and reduced rate discharge performance. Uneven permeability causes differences in ion concentration across different areas of the battery, leading to localized current concentration, accelerated electrode material aging, shortened cycle life, and even exceeding the separator's thermal pore temperature due to localized overheating, triggering safety risks. For example, the consistency of permeability along the separator's length determines the consistency of subsequent battery products. If the permeability deviation along the separator's length is too large, different segments cut from the same roll of separator used to manufacture batteries will exhibit batch-specific differences, such as some batteries with poor rate performance and others with short cycle life, affecting the consistency of battery products. If the air permeability is not consistent in the width direction of the separator, the assembled battery may have local air permeability that is too low, which may cause a short circuit, or local air permeability that is too high, which may cause local overcharging and thus accelerate thermal runaway.

[0032] It should be noted that in this application, "diaphragm length direction" refers to the direction in which the diaphragm moves along the conveying equipment during continuous production, and is also the direction in which the finished roll of diaphragm unfolds and extends during subsequent use. In other words, if the roll of diaphragm is regarded as a roll of cloth, the direction in which the diaphragm extends with the tension when it is pulled from the roll is the length direction.

[0033] In this application, "width direction" can also be understood as "width direction," referring to the horizontal dimension perpendicular to the conveying direction of diaphragm production, and also the width dimension corresponding to the radial direction of the finished diaphragm roll. In other words, if the diaphragm roll is regarded as a roll of fabric, the width direction is the width direction between the left and right ends of the fabric after it is unfolded, which is the dimension perpendicular to the length of the fabric.

[0034] This application discloses a device for testing the air permeability of lithium battery separator samples (hereinafter referred to as the "testing device"). Unlike traditional unwinding and rewinding testing devices, it features a simple structure, convenient operation, and the ability to perform multi-dimensional testing. The testing device includes a testing platform, a sample delivery mechanism, and a testing mechanism. Both the sample delivery mechanism and the testing mechanism are mounted on the testing platform. The sample delivery mechanism is used to transport the separator sample, and the testing mechanism is used to test the air permeability of the separator sample. In practical applications, the sample delivery mechanism and the testing mechanism can be clamped onto the separator sample to hold and fix it. As the test at a certain position of the separator sample is completed, the sample delivery mechanism transports the separator sample so that the next position to be tested is located at the testing mechanism. Through the cooperation of the sample delivery mechanism and the testing mechanism, continuous measurement at different positions of a section of separator sample can be achieved, which helps to accurately obtain the air permeability consistency of the separator sample along the transport direction. Furthermore, this testing device has relatively small requirements for the size of the separator sample and can perform multi-dimensional measurements on the separator sample. For example, when testing the air permeability consistency in the width direction of the diaphragm, a diaphragm sample of a suitable size (e.g., 50 mm) is cut from the rolled diaphragm. The width direction of the diaphragm is placed parallel to the conveying direction (i.e., the second direction). As the sample feeding mechanism moves, the diaphragm is conveyed along its own width direction to obtain multiple different air permeability values ​​in the width direction, thereby testing the air permeability consistency of the diaphragm in the width direction. Of course, this testing device can also be used to measure the air permeability consistency in the length direction of the diaphragm. During the test, the length direction of the diaphragm is placed parallel to the conveying direction (i.e., the second direction). Since the length of the rolled diaphragm is relatively long (1000m-5000m), it is necessary to manually unwind the diaphragm to prepare multiple samples for testing.

[0035] Please see Figures 1 to 6 The testing device includes a testing platform 100, a sample delivery mechanism 200, and a testing mechanism 300.

[0036] The test platform 100 serves as the support and basic structure of the entire testing device. It provides an installation foundation for the sample delivery mechanism 200 and the testing mechanism 300, so as to integrate the testing mechanism 300 and the sample delivery mechanism 200, improve the overall integrity of the testing device, reduce the area occupied by the testing device, and facilitate integrated transportation and mobile testing device.

[0037] Please see Figure 2The sample delivery mechanism 200 is mounted on the test platform 100. The sample delivery mechanism 200 includes a sample delivery drive assembly 210, a transmission roller 220, and a driven roller 230. The output end of the sample delivery drive assembly 210 is connected to the transmission roller 220 to drive its rotation. The driven roller 230 is positioned opposite the transmission roller 220 along a first direction F1, and the driven roller 230 cooperates with the transmission roller 220 to form a clamping gap 240 for clamping the diaphragm sample and conveying it along a second direction F2. Both the transmission roller 220 and the driven roller 230 can be made of materials such as aluminum alloy or stainless steel. Rollers made of aluminum alloy have a smooth surface, which reduces the impact on the surface quality of the diaphragm sample, thus avoiding affecting the accuracy of the permeability test results. Rollers made of aluminum alloy also have good wear resistance, which helps to extend the service life of the testing device. The sample delivery drive assembly 210 can be connected to the transmission roller 220 via a drive shaft, which is located at the output end of the sample delivery drive assembly 210.

[0038] Please continue reading. Figure 2 The testing mechanism 300 is disposed on the testing platform 100 and is positioned on one side of the sample delivery mechanism 200 along the second direction F2; the testing mechanism 300 is used to test the air permeability of the diaphragm sample. The first direction F1 and the second direction F2 are perpendicular to each other.

[0039] It should be noted that the second direction F2 is the conveying direction of the diaphragm sample. In some examples, the sample feeding mechanism 200 can be located upstream of the testing mechanism 300, meaning the diaphragm sample enters the testing mechanism 300 after being conveyed by the sample feeding mechanism 200, and then the area to be tested is tested. In other examples, the sample feeding mechanism 200 can be located downstream of the testing mechanism 300, meaning the diaphragm sample is tested by the testing mechanism 300 first, and then conveyed by the sample feeding mechanism 200. In this example, since the diaphragm sample is tested first and then passes through the clamping gap 240 between the drive roller 220 and the driven roller 230 of the sample feeding mechanism 200, the influence of the drive roller 220 and the driven roller 230 clamping the diaphragm sample on the air permeability test of the diaphragm sample can be reduced. Upstream and downstream are defined according to the product's production process. If one mechanism provides the raw materials required for the production of another mechanism, then this mechanism is located upstream of the other mechanism, and the other mechanism is located downstream of this mechanism. For example, the diaphragm sample is tested first and then transported. The testing mechanism 300 is located upstream of the sample delivery mechanism 200, and the sample delivery mechanism 200 is located downstream of the testing mechanism 300.

[0040] Please see Figure 1 and Figure 2In some embodiments, the air permeability testing device further includes a lifting mechanism 400, which is connected to the sample delivery drive assembly 210 and is used to drive the sample delivery drive assembly 210 to move along the first direction F1, thereby driving the transmission roller 220 to move closer to or further away from the driven roller 230 to adjust the size of the clamping gap 240, thereby clamping or releasing the diaphragm sample. In practical applications, when the testing mechanism 300 is located upstream of the sample delivery mechanism 200, one end of the diaphragm sample is first placed at the testing mechanism 300, and the other end is spread on the driven roller 230. The operator can manually move the diaphragm sample to complete the air permeability test of the diaphragm sample in the entire conveying direction. At this time, the lifting mechanism 400 can be used to move the transmission roller 220 away from the driven roller 230 to provide sufficient operating space. Alternatively, the lifting mechanism 400 can be used to move the drive roller 220 away from the driven roller 230, spread the diaphragm sample on the driven roller 230, and then the lifting mechanism 400 can be used to move the drive roller 220 closer to the driven roller 230 to clamp the diaphragm sample. Then, the sample feeding drive assembly 210 can be used to drive the drive roller 220 to rotate and move the diaphragm sample along the conveying direction (or the second direction F2). After the test is completed, the lifting mechanism 400 can be operated to move the drive roller 220 away from the driven roller 230 to facilitate the removal of the diaphragm sample.

[0041] Please see Figure 1 and Figure 2 In some embodiments, the lifting mechanism 400 includes a lifting drive assembly 410 and a bracket 420. The bracket 420 is connected to the output end of the lifting drive assembly 410. The sample feeding drive assembly 210 is disposed on the bracket 420. The lifting drive assembly 410 is used to drive the bracket 420 to move along the first direction F1, thereby driving the transmission roller 220 to move closer to or further away from the driven roller 230 along the first direction F1.

[0042] Please see Figure 1 In some embodiments, the testing device may further include a mounting frame 500, which is disposed on the test platform 100 and has guide rails (not shown) extending along a first direction F1. A bracket 420 is movably connected to the guide rails, allowing the bracket 420 to move along the guide rails to ensure stable movement of the drive roller 220. A limiting member may be provided at the end of the mounting frame 500 away from the driven roller 230 to limit the movement limit of the bracket 420, thereby limiting the travel of the drive roller 220. In one example, the mounting frame 500 is constructed in a U-shape, with the limiting member at the bottom of the U-shape and guide rails on both sides of the U-shape.

[0043] In some embodiments, the lifting drive assembly 410 includes a linear cylinder or a linear motor. The function of the lifting drive assembly 410 is to provide linear driving force to the transmission roller 220 along the first direction F1. Using a linear cylinder or linear motor directly can simplify the structure of the lifting drive assembly 410, thereby simplifying the structure of the entire detection device.

[0044] Of course, in other embodiments, the lifting drive assembly 410 may include a rotary motor and a transmission mechanism. The transmission mechanism can convert the rotational motion of the rotary motor into linear motion. The transmission mechanism may be a combination of a lead screw and a slider, a combination of a transmission wheel and a transmission belt, or a combination of a gear and a rack.

[0045] In some embodiments, the sample delivery drive assembly 210 includes a stepper motor. Diaphragm permeability testing requires collecting data at specific points along the length or width direction (e.g., testing one point every 50mm). The sample delivery drive assembly 210 uses a stepper motor, which can control the rotation angle based on its pulse signal to achieve precise length control, ensuring consistent distance between adjacent test points and guaranteeing that the diaphragm sample is accurately delivered to the test area according to a preset length. This avoids misalignment of test points due to delivery deviations, thereby ensuring the authenticity of the permeability test data. In some examples, the stepper motor can also be replaced with a servo motor, which also has the characteristic of accurate sample delivery.

[0046] In some embodiments, the testing mechanism 300 includes a first test clamp 310, a second test clamp 320, a test drive assembly 330, a gas delivery assembly 340, and a test assembly 350. The first test clamp 310 and the second test clamp 320 are arranged sequentially along a first direction F1 for sealing and clamping the diaphragm sample. The gas delivery assembly 340 is disposed within the first test clamp 310 for delivering gas at a constant pressure to the diaphragm sample. The test assembly 350 is disposed within the second test clamp 320 for detecting the gas passing through the diaphragm sample. The test drive assembly 330 is connected to the first test clamp 310 for driving the first test clamp 310 to move closer to or away from the second test clamp 320 along the first direction F1. In practical applications, the diaphragm sample is placed between the first test clamp 310 and the second test clamp 320. The gas delivery assembly 340 delivers gas through the diaphragm sample in a first direction F1. The test assembly 350 tests the gas passing through the diaphragm sample. By comparing the gas delivered by the gas delivery assembly 340 with the gas measured at the test assembly 350, the permeability value of the diaphragm sample is calculated. The gas delivery assembly 340 includes a pump and a delivery pipe to deliver gas with a specific pressure or flow rate to the diaphragm sample. The test assembly 350 includes a flow sensor or a pressure sensor to monitor the gas flow rate or pressure passing through the diaphragm sample. For example, the gas delivery assembly 340 includes a gas flow meter, and the test assembly 350 includes a flow sensor; permeability is detected by monitoring the gas flow rate on both sides of the diaphragm sample. Both the gas delivery assembly 340 and the test assembly 350 include pressure sensors; permeability is detected by monitoring the air pressure on both sides of the diaphragm sample. The opposing end faces of the first test chuck 310 and the second test chuck 320 are flush and smooth, which helps to form a sealed measurement space between them, so as to effectively ensure the accuracy of the test results.

[0047] In some embodiments, the test drive assembly 330 includes a linear cylinder or a linear motor.

[0048] Please see Figure 3In some embodiments, the test platform 100 is provided with a first mounting cavity 110, and a second test chuck 320 is disposed in the first mounting cavity 110, so that the central axis of the driven roller 230 is flush with the end face of the second test chuck 320 facing the first test chuck 310. The test platform 100 is provided with a second mounting cavity 120, and a bearing seat 130 is provided at the bottom of the second mounting cavity 120. Both ends of the driven roller 230 are rotatably disposed in the bearing seat 130 through bearings. The second mounting cavity 120 and the first mounting cavity 110 are flush in the first direction F1, that is, the central axis of the driven roller 230 and the end face of the second test chuck 320 facing the first test chuck 310 are on the same horizontal plane, ensuring that the diaphragm sample smoothly enters or moves away from the test mechanism 300 along the second direction F2, and that the diaphragm sample remains horizontal when transported between the sample feeding mechanism 200 and the test mechanism 300, avoiding wrinkles in the diaphragm sample due to height differences, which would affect the detection accuracy.

[0049] Please see Figure 4 and Figure 5 In some embodiments, the first test clamp 310 has a first cavity 311, the second test clamp 320 has a second cavity 321, the gas delivery assembly 340 is disposed in the first cavity 311, and the test assembly 350 is disposed in the second cavity 321. The orthographic projections of the first cavity 311 and the second cavity 321 in the first direction F1 coincide, which helps to ensure that the first cavity 311 and the second cavity 321 cover the test area on the diaphragm sample, ensuring that the gas delivered by the gas delivery assembly 340 can act entirely on the detection area of ​​the diaphragm sample, and completely enter the second cavity 321 after passing through the diaphragm sample to be detected by the test assembly 350, avoiding gas leakage that could lead to detection errors. In one example, the first cavity 311 may have a gas guide groove (not shown) to uniformly deliver gas to the test area.

[0050] Please see Figure 6In some embodiments, the air permeability testing device further includes a display component 600 and a controller 700. The controller 700 is connected to the sample delivery mechanism 200 and is used to trigger the start of the sample delivery mechanism 200. The controller 700 is also connected to the testing mechanism 300 and is used to trigger the start of the testing mechanism 300 and collect the air permeability value of the diaphragm sample. The display component 600 is connected to the controller 700 and is used to display the air permeability value measured by the testing mechanism 300. In one example, the controller 700 is a PLC or an industrial control board. The controller 700 is electrically connected to the sample delivery drive component 210 of the sample delivery mechanism 200 and the lifting drive component 410 of the lifting mechanism 400. It can trigger the start of the sample delivery mechanism 200 through a preset program or manually and precisely control the delivery rate and distance. The controller 700 is also electrically connected to the testing mechanism 300 and is used to trigger the start of the testing mechanism 300 and collect test data (such as pressure or flow rate) in real time. The display component 600 is a touch screen that communicates bidirectionally with the controller 700. It can display test parameters (such as gas pressure or gas flow rate) so that the operator can view them intuitively in real time.

[0051] The above examples illustrate this application only to aid understanding and are not intended to limit its scope. Those skilled in the art to which this application pertains can make various simple deductions, modifications, or substitutions based on the ideas presented.

Claims

1. A device for detecting the air permeability of lithium battery separator samples, characterized in that, include: Test platform; A sample delivery mechanism, which is disposed on the test platform; The sample feeding mechanism includes a sample feeding drive assembly, a transmission roller, and a driven roller. The output end of the sample feeding drive assembly is connected to the transmission roller and is used to drive the transmission roller to rotate. The driven roller and the transmission roller are arranged opposite to each other in a first direction. The driven roller and the transmission roller cooperate to form a clamping gap for clamping the diaphragm sample and conveying the diaphragm sample in a second direction. as well as The testing mechanism is disposed on the testing platform and is located on one side of the sample delivery mechanism along the second direction; the testing mechanism is used to test the air permeability of the diaphragm sample. Wherein, the first direction and the second direction are perpendicular to each other.

2. The air permeability testing device for lithium battery separator samples according to claim 1, characterized in that, The air permeability testing device further includes a lifting mechanism connected to the sample delivery drive assembly, which drives the sample delivery drive assembly to move along the first direction to move the transmission roller closer to or away from the driven roller, thereby adjusting the size of the clamping gap and clamping or releasing the diaphragm sample.

3. The air permeability testing device for lithium battery separator samples according to claim 2, characterized in that, The lifting mechanism includes a lifting drive assembly and a bracket. The bracket is connected to the output end of the lifting drive assembly. The sample delivery drive assembly is disposed on the bracket. The lifting drive assembly is used to drive the bracket to move along the first direction.

4. The air permeability testing device for lithium battery separator samples according to claim 3, characterized in that, The lifting drive assembly includes a linear cylinder or a linear motor.

5. The air permeability testing device for lithium battery separator samples according to claim 1, characterized in that, The sample delivery drive assembly includes a stepper motor.

6. The air permeability testing device for lithium battery separator samples according to claim 1, characterized in that, The testing mechanism includes a first test clamp, a second test clamp, a test drive assembly, a gas delivery assembly, and a test assembly. The first test clamp and the second test clamp are arranged sequentially along the first direction for sealing and clamping the diaphragm sample. The gas delivery assembly is disposed within the first test clamp for delivering gas at a constant pressure to the diaphragm sample. The test assembly is disposed within the second test clamp for detecting the gas passing through the diaphragm sample. The test drive assembly is connected to the first test clamp and is used to drive the first test clamp to move closer to or further away from the second test clamp along the first direction.

7. The air permeability testing device for lithium battery separator samples according to claim 6, characterized in that, The first test clamp has a first cavity, and the second test clamp has a second cavity. The orthographic projections of the first cavity and the second cavity in the first direction coincide.

8. The air permeability testing device for lithium battery separator samples according to claim 6, characterized in that, The test platform is provided with a first mounting cavity, and the second test chuck is disposed in the first mounting cavity so that the central axis of the driven roller is flush with the end face of the second test chuck facing the first test chuck.

9. The air permeability testing device for lithium battery separator samples according to claim 8, characterized in that, The test platform is provided with a second mounting cavity, and the bottom of the second mounting cavity is provided with a bearing seat. The two ends of the driven roller are rotatably mounted in the bearing seat through bearings. The second mounting cavity and the first mounting cavity are flush with each other in the first direction.

10. The air permeability testing device for lithium battery separator samples according to claim 1, characterized in that, The air permeability testing device also includes a display component and a controller. The controller is connected to the sample delivery mechanism and is used to trigger the sample delivery mechanism to start. The controller is also connected to the testing mechanism and is used to trigger the testing mechanism to start and collect the air permeability value of the membrane sample. The display component is connected to the controller and is used to display the air permeability value measured by the testing mechanism.

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