Detection device and detection method for diaphragm performance

Abstract

The invention discloses a diaphragm performance detection device, a diaphragm forms a roll core in a cylindrical battery, the roll core is provided with a plurality of winding layers, the diaphragm is provided with a first end and a second end which are oppositely arranged along an unfolding direction, and the detection device comprises a tensile machine which comprises a first connecting end and a second connecting end and is used for stretching the diaphragm; a steering column includes: a fixed shaft; the multiple sleeving cylinders are different in radius and can be arranged on the periphery of the fixing shaft in a sleeving mode, so that the steering column has multiple different radiuses, the multiple different radiuses of the steering column are matched with the vertical distances from the multiple winding layers to the central axis of the winding core respectively, the steering column is provided with a center shaft, and the center shaft is perpendicular to the tension direction of the tension machine; the first end is connected with the first connecting end, the second end bypasses the peripheral wall of the steering column and is connected with the second connecting end, and the peripheral wall of part of the steering column is in contact with the diaphragm, so that the tensile machine stretches the diaphragm under the condition that the diaphragm is wound on the steering columns with different radiuses. The invention also discloses a diaphragm performance detection method.

Description

Technical Field

[0001] This invention relates to the field of batteries, and in particular to a device and method for testing the performance of a separator. Background Technology

[0002] The separator is a crucial component of a battery, primarily serving to wet the electrolyte and isolate the positive and negative electrodes. Its main characteristics include excellent electronic insulation, good electrolyte wettability, and appropriately sized pores for ion movement between the electrodes. Although the separator itself does not directly provide energy to the battery, its performance affects the battery's electrochemical and safety performance. Therefore, testing methods for separator performance play a critical role in battery design. Among these, the separator's mechanical properties and heat resistance are essential for the cell's safety performance.

[0003] Currently, the industry generally uses national standard testing methods to evaluate separator performance. These methods are mainly based on testing the separator in a flat, unstressed state to obtain basic performance parameters. However, in cylindrical battery applications, the separator is not freely unfolded in the actual working environment. It is wound into a core with multiple winding layers. The actual performance of the separator varies depending on the location (i.e., different winding layers) and the battery operating conditions. In fact, the actual performance of the separator in the battery may be lower than the results measured in the freely unfolded state. Therefore, the separator parameters measured by conventional national standard methods cannot reflect the actual performance of the separator in cylindrical battery applications. Summary of the Invention

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a device and method for testing diaphragm performance.

[0005] In a first aspect, embodiments of the present invention provide a device for testing the performance of a separator, the separator being used in a cylindrical battery and forming a core in the cylindrical battery, the core having multiple winding layers, the separator having a first end and a second end disposed opposite to each other along the unfolding direction, the testing device comprising:

[0006] A tensile testing machine, including a first connecting end and a second connecting end, is used to stretch the diaphragm;

[0007] Steering column, including:

[0008] Fixed shaft;

[0009] The sleeve has multiple sleeves, each with a different radius, and can be respectively sleeved on the outer periphery of the fixed shaft, so that the steering column has multiple different radii. The multiple different radii of the steering column are respectively matched with the vertical distance from the central axis of the multiple winding layers to the core. The steering column has a central axis, which is perpendicular to the tensile force direction of the tensile testing machine.

[0010] The first end is connected to the first connecting end, and the second end is connected to the second connecting end by bypassing the peripheral wall of the steering column. Part of the peripheral wall of the steering column is in contact with the diaphragm, so that the tensioning machine stretches the diaphragm when the diaphragm is wrapped around the steering column with different radii.

[0011] By adopting the above technical solution, the tensile state of the separator in different winding layers in the battery can be simulated. By testing the performance of the separator in the tensile state, the corresponding performance of the separator in different winding layers in the core under the tensile state can be determined, breaking the limitation of traditional testing being detached from actual working conditions.

[0012] According to another specific embodiment of the present invention, the tensile force direction of the tensile testing machine is perpendicular to the vertical direction.

[0013] According to another specific embodiment of the present invention, the detection device further includes a steering shaft, the steering column is located between the tensile testing machine and the steering shaft along a first direction, the steering shaft includes a first steering shaft and a second steering shaft, the steering column is located between the first steering shaft and the second steering shaft along the vertical direction, the first connecting end and the second connecting end are arranged opposite to each other along the vertical direction; the first end and the first connecting end are connected, and the second end passes through the peripheral wall of the first steering shaft, the peripheral wall of the steering column and the peripheral wall of the second steering shaft in sequence before being connected to the second connecting end;

[0014] The first connecting end has a first connecting position connected to the first end, the second connecting end has a second connecting position connected to the second end, the first steering shaft has a first top contact position and a first bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the second steering shaft has a second top contact position and a second bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the steering column has a third top contact position and a third bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the first connecting position and the first top contact position are at the same height along the vertical direction, the first bottom contact position and the third top contact position are at the same height along the vertical direction, the third bottom contact position and the second top contact position are at the same height along the vertical direction, the second bottom contact position and the second connecting position are at the same height along the vertical direction, and the first direction is parallel to the tension direction of the tensioning machine.

[0015] According to another specific embodiment of the present invention, the direction of the first connection position toward the first top contact position is parallel and opposite to the direction of the first bottom contact position toward the third top contact position, and the direction of the third bottom contact position toward the second top contact position is parallel and opposite to the direction of the second bottom contact position toward the second connection position.

[0016] According to another specific embodiment of the present invention, the fixed shaft is provided with a heating assembly, which is used to heat the sleeve through the fixed shaft, thereby heating the diaphragm surrounding the peripheral wall of the sleeve.

[0017] According to another specific embodiment of the present invention, the detection device includes a puncture intensity detection component for detecting the puncture intensity of the diaphragm. The puncture intensity detection component includes a puncture needle, and the peripheral wall of the sleeve is provided with a puncture hole for the puncture needle to insert after puncturing the diaphragm.

[0018] According to another specific embodiment of the present invention, a plurality of the sleeves are coaxially sleeved on the fixed shaft, and adjacent sleeves are detachably connected.

[0019] Secondly, embodiments of the present invention also provide a method for detecting diaphragm performance, employing a detection device as described in any embodiment of the first aspect, the detection method comprising the following steps:

[0020] The first connecting end is connected to the first end of the diaphragm, and the second end is connected to the second connecting end by bypassing the peripheral wall of the steering column, with part of the peripheral wall of the steering column in contact with the diaphragm;

[0021] The diaphragm, which is wound around the steering column with different radii, is stretched using the tensile testing machine to detect its performance under tension.

[0022] By adopting the above technical solution, the tensile state of the separator in different winding layers in the battery can be simulated. By testing the performance of the separator in the tensile state, the corresponding performance of the separator in different winding layers in the core under the tensile state can be determined, breaking the limitation of traditional testing being detached from actual working conditions.

[0023] According to another specific embodiment of the present invention, the maximum value of the tensile force on the diaphragm wound on the steering column with different radii in the tensile state is obtained by the tensile testing machine, thereby determining the tensile strength of the diaphragm wound on the steering column with the corresponding radius.

[0024] According to another specific embodiment of the present invention, the fixed shaft is provided with a heating assembly, which is used to heat the sleeve through the fixed shaft, thereby heating the diaphragm wound around the side wall of the sleeve. The detection method includes: adjusting the heating temperature of the heating assembly, and stretching the diaphragm wound on the steering column with different radii at different heating temperatures using the tensile testing machine, thereby determining the tensile strength of the diaphragm wound on the steering column with different radii at different heating temperatures.

[0025] And / or, the detection method includes: setting the heating rate of the heating component to 1~5℃ / min, setting the tensile testing machine to a constant tensile force mode, wherein the constant tensile force has multiple values, the multiple constant tensile force values ​​are different, the multiple constant tensile force values ​​are respectively matched with the tensile force values ​​of the multiple winding layers in the cylindrical battery, the multiple constant tensile force values ​​respectively correspond to multiple different radii of the steering column, and monitoring the change of the deformation of the separator wound on the steering column with different radii under the corresponding constant tensile force with the change of heating temperature, thereby determining the pore-closing temperature and the membrane-breaking temperature of the separator on the steering column with different radii under the corresponding constant tensile force; the pore-closing temperature is the temperature corresponding to the peak value of the deformation as the heating temperature increases, and the membrane-breaking temperature is the temperature corresponding to the valley value after the peak value of the deformation as the heating temperature increases.

[0026] According to another specific embodiment of the present invention, the detection device includes a puncture intensity detection component, which is used to detect the puncture intensity of the diaphragm. The puncture intensity detection component includes a puncture needle, and the peripheral wall of the sleeve is provided with a puncture hole, which is used for the puncture needle to puncture the diaphragm and then insert itself.

[0027] The detection method includes: adjusting the heating temperature of the heating component, setting the tensile testing machine to the constant tensile force mode, and using the puncture needle to puncture the diaphragm wound on the steering column with different radii under the corresponding constant tensile force and different heating temperatures to insert into the puncture hole, thereby determining the penetration strength of the diaphragm wound on the steering column with different radii under the corresponding constant tensile force and different heating temperatures. Attached Figure Description

[0028] Figure 1 A schematic diagram of the detection device in an embodiment of the present invention is shown;

[0029] Figure 2 A schematic diagram of the sleeve structure in an embodiment of the present invention is shown.

[0030] 100. Detection device, 0. Diaphragm, 01. First end, 02. Second end, 101. First connection position, 102. Second connection position, 1. Tensile testing machine, 11. First connection end, 12. Second connection end, 2. Steering column, 21. Fixed shaft, 22. Sleeve, 221. Puncture hole, 222. Fixed hole, 223. Third top contact position, 224. Third bottom contact position, 3. Steering shaft, 31. First steering shaft, 311. First top contact position, 312. First bottom contact position, 32. Second steering shaft, 321. Second top contact position, 322. Second bottom contact position, F. Tensile direction, x. First direction, y. Vertical direction, a. Central axis of sleeve. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention is presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to these embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a deep understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0032] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0033] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0034] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0036] In existing technologies, the industry generally uses national standard testing methods to directly test the separator. This only obtains the separator's performance parameters under ideal conditions and cannot reflect its actual performance in a real battery environment. Therefore, existing technologies also simulate the actual curling state of the separator to test its performance. In practical applications of cylindrical batteries, the separator forms a core within the cylindrical battery. This core has multiple winding layers, and the separator exhibits performance differences at different winding layers (i.e., different positions) due to variations in bending radius and stress state. However, existing technologies all ignore these performance differences at different winding layers (i.e., different positions), resulting in test results that still cannot accurately reflect the separator's true performance under complex internal battery conditions. This severely impacts the accurate evaluation and optimization design of battery performance.

[0037] For example, the performance of the outermost separator in a battery cell is used as a standard, and the performance of the innermost separator is required to be the same as that of the outermost separator. However, in practical applications, because the innermost separator has the smallest bending radius and the outer layer applies continuous radial pressure to the inner layer during winding, it experiences the greatest stress. Therefore, the actual performance requirements for the innermost separator are greater than those for the outermost separator. Setting the performance of the innermost and outermost separators to be the same would lead to premature failure of the innermost separator under actual operating conditions due to insufficient performance redundancy, resulting in risks such as wrinkling, cracking, and deterioration of thermal stability, thus affecting the overall safety and cycle life of the battery.

[0038] To solve the above problems, firstly, refer to Figure 1As shown, an embodiment of the present invention provides a membrane performance testing device 100. The membrane 0 is used in a cylindrical battery and forms a core in the cylindrical battery. The core has multiple winding layers. The membrane 0 has a first end 01 and a second end 02 arranged opposite to each other along the unfolding direction. The testing device 100 includes a tensile testing machine 1 and a steering column 2.

[0039] Specifically, the tensile testing machine 1 includes a first connecting end 11 and a second connecting end 12, and the tensile testing machine 1 is used to stretch the diaphragm 0.

[0040] Specifically, the steering column 2 includes a fixed shaft 21 and multiple sleeves 22, each with a different radius, which can be respectively fitted onto the outer periphery of the fixed shaft 21. This results in the steering column 2 having multiple different radii, each matching the vertical distance from the winding layer to the centerline of the core, thus simulating the scenario where the diaphragm 0 is located in different winding layers. Further, the multiple different radii of the steering column 2 are consistent with the vertical distance from the winding layer to the centerline of the core. Even further, the multiple different radii of the steering column 2 are equal to the vertical distance from the winding layer to the centerline of the core. The steering column 2 has a central axis, which is perpendicular to the tension direction of the tensioning machine 1 (e.g., ...). Figure 1 The direction shown is F). The central axis of steering column 2 is... Figure 2 The central axis a of the sleeve shown is perpendicular to the tension direction of the tensioning machine 1 (e.g., ...). Figure 1 The direction shown is F).

[0041] In this design, the first end 01 is connected to the first connecting end 11, and the second end 02 bypasses the peripheral wall of the steering column 2 and connects to the second connecting end 12. A portion of the peripheral wall of the steering column 2 contacts the separator 0. Thus, the tensile testing machine 1 stretches the separator 0 when it is wound around steering columns 2 of different radii, simulating the stretching state of the separator 0 in different winding layers within the battery. By testing the performance of the separator 0 under stretching conditions, the corresponding performance of the separator 0 in different winding layers within the core under stretching conditions is determined, such as tensile strength, puncture strength, tensile strength, rupture temperature, and pore-closing temperature.

[0042] Specifically, the multiple sleeves 22 of the steering column 2 have different radii, and these radii match the vertical distance from each winding layer to the central axis of the core. This allows the steering column 2 to reproduce the bending environment of the separator 0 when it is in different winding layers by using sleeves 22 with different radii. The first end 01 of the separator 0 is fixed to the first connecting end 11, and the second end 02 passes around the peripheral wall of the steering column 2 and connects to the second connecting end 12. The tensile force applied by the tensile testing machine 1 can simulate the stress state of the separator 0 in different winding layers inside the battery. Under this state, performance parameters such as tensile strength and puncture strength are detected, which directly reflect the performance of the separator 0 under actual working conditions. This makes the performance testing of the separator 0 no longer limited to the ideal state, but covers the entire range from the inner layer of the core to the outer layer of the core (i.e., located in the first winding layer to the Nth winding layer). Under actual stress conditions, the performance of the separator 0 at different positions is detected, providing a basis for optimizing the separator 0 and improving battery safety and reliability, which is beneficial to reducing the risk of battery failure due to insufficient performance of the separator 0.

[0043] By adopting the above technical solution, the present invention can simulate the stress state of the separator 0 in different winding layers in the battery core through the cooperation of the tensile testing machine 1 and the steering column 2, and then detect the performance of the separator 0 in the corresponding state, breaking the limitation of traditional testing being divorced from actual working conditions.

[0044] In some other possible embodiments provided by the present invention, the direction of the tensile force of the tensile testing machine (e.g.) Figure 1 The direction F shown is perpendicular to the vertical direction (e.g., Figure 1 The direction shown is y). Specifically, the vertical direction (e.g.) Figure 1 The direction y shown is the direction of gravity of the diaphragm 0, that is, the direction of the tension of the tensile testing machine (e.g., Figure 1 The direction F shown is perpendicular to the direction of gravity of the diaphragm 0, which effectively eliminates the interference of the gravity of the diaphragm 0 on the tensile testing machine 1, thereby ensuring the accuracy of the performance test of the diaphragm 0.

[0045] In some other possible embodiments provided by the present invention, the detection device 100 further includes a steering shaft 3, and a steering column 2 is located between the tension machine 1 and the steering shaft 3 along a first direction. The steering shaft 3 includes a first steering shaft 31 and a second steering shaft 32, and the steering column 2 is located between the first steering shaft 31 and the second steering shaft 32 along a vertical direction. A first connecting end 11 and a second connecting end 12 are arranged opposite each other along a vertical direction. The first end 01 is connected to the first connecting end 11, and the second end 02 passes through the peripheral wall of the first steering shaft 31, the peripheral wall of the steering column 2, and the peripheral wall of the second steering shaft 32 in sequence, and then connects to the second connecting end 12.

[0046] The first connecting end 11 has a first connecting position 101 connected to the first end 01; the second connecting end 12 has a second connecting position 102 connected to the second end 02; the first steering shaft 31 has a first top contact position 311 and a first bottom contact position 312 that are in contact with the diaphragm 0 and are arranged opposite each other in the vertical direction; the second steering shaft 32 has a second top contact position 321 and a second bottom contact position 322 that are in contact with the diaphragm 0 and are arranged opposite each other in the vertical direction; the steering column 2 has a third top contact position 223 and a third bottom contact position 224 that are in contact with the diaphragm 0 and are arranged opposite each other in the vertical direction. The first connecting position 101 and the first top contact position 311 are at the same height in the vertical direction; the first bottom contact position 312 and the third top contact position 223 are at the same height in the vertical direction; the third bottom contact position 224 and the second top contact position 321 are at the same height in the vertical direction; the second bottom contact position 322 and the second connecting position 102 are at the same height in the vertical direction. (e.g., in the first direction...) Figure 1 The direction x shown is parallel to the direction of the tension of the tensile testing machine (e.g., Figure 1 The direction shown is F).

[0047] The present invention, by setting the first connecting position 101 and the first top contact position 311 at the same height in the vertical direction, the first bottom contact position 312 and the third top contact position 223 at the same height in the vertical direction, the third bottom contact position 224 and the second top contact position 321 at the same height in the vertical direction, and the second bottom contact position 322 and the second connecting position 102 at the same height in the vertical direction, can further ensure the elimination of the interference of the diaphragm 0's gravity on performance testing and improve the accuracy of performance testing.

[0048] Specifically, the sum of the diameters of the first steering shaft 31, the second steering shaft 32, and the steering column 2 is the vertical distance between the first connection position 101 and the second connection position 102. For example, the diameters of the first steering shaft 31 and the second steering shaft 32 are equal, which helps to enhance the balance of force transmission and reduce the risk of lateral deviation. For example, the steering shaft 3 has multiple sizes; specifically, the diameters of the first steering shaft 31 and the second steering shaft 32 are not equal, allowing for differentiated design to adapt to special testing requirements, such as simulating asymmetric force scenarios.

[0049] In some other possible embodiments provided by the present invention, in the vertical direction (e.g.) Figure 1In the direction y shown, the positions of the first connecting position 101 and the second connecting position 102 are adjustable, and the positions of the first steering shaft 31 and the second steering shaft 32 are adjustable, so that the first connecting position 101 and the first top contact position 311 are at the same height in the vertical direction, the first bottom contact position 312 and the third top contact position 223 are at the same height in the vertical direction, the third bottom contact position 224 and the second top contact position 321 are at the same height in the vertical direction, and the second bottom contact position 322 and the second connecting position 102 are at the same height in the vertical direction.

[0050] In some other possible embodiments provided by the present invention, there are multiple steering shafts 3, and the sum of the diameters of the multiple steering shafts 3 and the diameter of the steering column 2 is the vertical distance between the first connecting end 11 and the second connecting end 12. The present invention does not impose a specific limitation on the number of steering shafts 3, and those skilled in the art can select them according to actual needs to eliminate the interference of the gravity of the diaphragm 0 on performance testing.

[0051] In some other possible embodiments provided by the present invention, the direction of the first connection position 101 toward the first top contact position 311 is parallel and opposite to the direction of the first bottom contact position 312 toward the third top contact position 223, and the direction of the third bottom contact position 224 toward the second top contact position 321 is parallel and opposite to the direction of the second bottom contact position 322 toward the second connection position 102. This balances the forces on each segment of the diaphragm 0, which helps improve the accuracy and stability of the detection, while reducing the risk of abnormal deformation or breakage of the diaphragm 0 due to force imbalance, thus ensuring the continuity of the detection process and the reliability of the data.

[0052] Furthermore, the extension direction of the diaphragm 0 from the first connecting position 101 to the first top contact position 311 is parallel to and opposite to the extension direction of the diaphragm 0 from the first bottom contact position 312 to the third top contact position 223, and the extension direction of the diaphragm 0 from the third bottom contact position 224 to the second top contact position 321 is parallel to and opposite to the extension direction of the diaphragm 0 from the second bottom contact position 322 to the second connecting position 102. Even further, the extension directions of the diaphragm 0 from the first connecting position 101 to the first top contact position 311, from the first bottom contact position 312 to the third top contact position 223, from the third bottom contact position 224 to the second top contact position 321, and from the second bottom contact position 322 to the second connecting position 102 are all perpendicular to the vertical direction (e.g., Figure 1 direction y shown).

[0053] In some other possible embodiments provided by the present invention, multiple sleeves 22 are coaxially sleeved on a fixed shaft 21 to form a steering column 2, and adjacent sleeves 22 are detachably connected. Specifically, multiple sleeves 22 with different radii are coaxially sleeved on the fixed shaft 21, and the different radii of the sleeves 22 are respectively matched with the vertical distances from the central axis of the multiple winding layers to the core. Further, the different radii of the sleeves 22 are respectively consistent with the vertical distances from the central axis of the multiple winding layers to the core. Even further, the different radii of the sleeves 22 are respectively equal to the vertical distances from the central axis of the multiple winding layers to the core. When it is necessary to test the performance of the separator located in a specific winding layer (i.e., a specific position), it is only necessary to match the radius of the outermost sleeve 22 of the steering column 2 with the vertical distance from the central axis of the specific winding layer to the core, so as to reproduce the bending state of the separator on the winding layer inside the battery, eliminating the complex equipment adjustment process, saving test preparation time, and improving testing efficiency.

[0054] In some other possible embodiments provided by the present invention, when it is necessary to test the performance of the diaphragm located on a specific winding layer (i.e., a specific position), it is only necessary to sleeve a connecting sleeve 22 whose radius matches the vertical distance from the specific winding layer to the centerline of the core to form a steering column 2 on the fixed shaft 21. Further, multiple different radii of the connecting sleeve 22 are respectively consistent with the vertical distances from multiple winding layers to the centerline of the core. Even further, multiple different radii of the connecting sleeve 22 are respectively equal to the vertical distances from multiple winding layers to the centerline of the core. Thus, by quickly replacing a single connecting sleeve 22, the bending condition of the diaphragm 0 from its position at the innermost layer (minimum radius) to its position at the outermost layer (maximum radius) of the core can be reproduced, which is beneficial to improving testing efficiency.

[0055] In any of the above embodiments, reference is made to Figure 1 and Figure 2 As shown, the fixed shaft 21 is equipped with a heating assembly, and the sleeve 22 is equipped with a fixing hole 222 for inserting the fixed shaft 21. The heating assembly can then heat the sleeve 22 through the fixed shaft 21, thereby heating the diaphragm 0 wrapped around the peripheral wall of the sleeve 22. This invention can simulate the temperature environment that the diaphragm 0 may face in actual applications (such as when the battery is working normally or abnormally), thereby enabling in-situ testing of the diaphragm 0 performance (such as tensile strength, puncture strength, and tensile strength) under different temperature conditions, as well as the performance of the diaphragm 0 at different locations under different temperatures (such as tensile strength, puncture strength, tensile strength, rupture temperature, and pore closure temperature), avoiding the problem of test data being out of sync with actual usage scenarios due to differences in ambient temperature.

[0056] This invention does not specifically limit the type of heating element; for example, the heating element can be one or more of resistance heating elements, induction heating elements, microwave heating elements, and infrared heating elements. Furthermore, technicians can also place the heating assembly in the sleeve 22 according to actual needs to achieve a more direct heat transfer path and a faster temperature response.

[0057] In any of the above embodiments, reference is made to Figure 2 As shown, the testing device 100 includes a puncture strength testing component, which is used to test the puncture strength of the separator 0. The puncture strength testing component includes a puncture needle, and the peripheral wall of the sleeve 22 is provided with a puncture hole 221 for the puncture needle to puncture the separator 0 and then insert itself. This allows the separator 0 to undergo puncture strength testing simultaneously or continuously during stretching and / or heating, simulating the stress and temperature environment of the separator 0 in a cylindrical battery under actual conditions. This more realistically reflects the potential puncture risk it may withstand, providing a more practical testing basis for evaluating the puncture resistance of the separator 0 in actual cylindrical battery applications.

[0058] Secondly, embodiments of the present invention also provide a method for detecting diaphragm performance, employing the detection device 100 as described in any embodiment of the first aspect, the detection method comprising the following steps:

[0059] The first connecting end 11 is connected to the first end 01 of the diaphragm 0, and the second end 02 is connected to the second connecting end 12 by passing around the peripheral wall of the steering column 2. Part of the peripheral wall of the steering column 2 is in contact with the diaphragm 0.

[0060] The diaphragm 0 is stretched by a tensile testing machine 1 on a steering column 2 with different radii, thereby testing the performance of the diaphragm 0 under tension.

[0061] By using the above technical solution, the separator 0 is stretched by the tensile testing machine 1 on the steering column 2 with different radii. This can simulate the stretching state of the separator 0 in the battery at different winding layers, and then test the performance of the separator 0 under the stretching state. The performance of the separator 0 in different winding layers in the core under the stretching state can be determined. The performance includes tensile strength, puncture strength, tensile strength, membrane rupture temperature and pore closure temperature. This breaks the limitation of traditional testing that is detached from actual working conditions.

[0062] In some other possible embodiments provided by the present invention, the maximum value of the tensile force on the diaphragm 0 wound on the steering column 2 with different radii is obtained by the tensile testing machine 1 under tension, thereby determining the tensile strength of the diaphragm 0 wound on the steering column 2 with the corresponding radius, that is, measuring the actual tensile strength performance of the diaphragm 0 in each winding layer of the cylindrical battery.

[0063] In some other possible embodiments provided by the present invention, the fixed shaft 21 is provided with a heating assembly, which is used to heat the sleeve 22 through the fixed shaft 21, thereby heating the diaphragm 0 wound on the side wall of the sleeve 22. The detection method includes: adjusting the heating temperature of the heating assembly, and stretching the diaphragm 0 wound on the steering column 2 with different radii at different heating temperatures using a tensile testing machine 1, thereby determining the tensile strength of the diaphragm 0 wound on the steering column 2 with different radii at different heating temperatures.

[0064] In some other possible embodiments provided by the present invention, the detection method further includes: setting the heating rate of the heating component to 1~5℃ / min, and setting the tensile testing machine 1 to a constant tensile force mode. The constant tensile force has multiple values, each different, and each value matches the tensile force exerted by a multiple winding layer in the cylindrical battery. Further, the values ​​of the multiple constant tensile forces are consistent with the tensile force exerted by the multiple winding layers in the cylindrical battery, and even further, the values ​​of the multiple constant tensile forces are equal to the tensile force exerted by the multiple winding layers in the cylindrical battery. The values ​​of the multiple constant tensile forces correspond to multiple different radii of the steering column, i.e., each constant tensile force value has a one-to-one corresponding steering column radius. In the cylindrical battery, the separators 0 located in different winding layers each have corresponding tensile force values ​​and radii.

[0065] In other words, this embodiment simulates the stress state of the separator 0 at different winding layers in a cylindrical battery, and detects the performance of the separator 0 under these conditions. Specifically, the deformation of the separator 0 wound on the steering column 2 with different radii under tension is monitored as a function of heating temperature, thereby determining the pore-closure temperature and rupture temperature of the separator 0 on the steering column 2 with different radii under the corresponding constant tension. The pore-closure temperature is the temperature corresponding to the peak value of the deformation as the heating temperature increases, and the rupture temperature is the temperature corresponding to the trough value of the deformation after the peak value as the heating temperature increases. Specifically, when the deformation first reaches a peak value as the heating temperature increases, the temperature corresponding to the peak value is determined as the pore-closure temperature of the separator 0 wound on the steering column 2 with the corresponding radius; when the deformation reaches a trough value after the peak value as the heating temperature increases, the temperature corresponding to the trough value is determined as the rupture temperature of the separator 0 wound on the steering column 2 with the corresponding radius.

[0066] In some other possible embodiments provided by the present invention, the detection device 100 includes a puncture intensity detection component for detecting the puncture intensity of the diaphragm 0. The puncture intensity detection component includes a puncture needle, and the peripheral wall of the sleeve 22 is provided with a puncture hole 221 for the puncture needle to be inserted after puncturing the diaphragm 0.

[0067] Furthermore, the testing method also includes: adjusting the heating temperature of the heating component, setting the tensile testing machine to a constant tensile force mode, and using a puncture needle to puncture the diaphragm 0 wound on the steering column 2 with different radii under the corresponding constant tensile force and different heating temperatures to insert into the puncture hole 221, thereby determining the penetration strength of the diaphragm 0 wound on the steering column 2 with different radii under the corresponding constant tensile force and different heating temperatures.

[0068] Specifically, the heating temperature of the heating component is adjusted, i.e., the heating component is set to a constant temperature. There are multiple constant temperatures, each with a different value, and each constant temperature value is matched to the temperature of the separator 0 under different operating conditions (e.g., normal operating conditions and abnormal operating conditions) in the cylindrical battery. Further, the multiple constant temperatures are consistent with the temperature of the separator 0 under different operating conditions (e.g., normal operating conditions and abnormal operating conditions) in the cylindrical battery. Even further, the multiple constant temperatures are equal to the temperature of the separator 0 under different operating conditions (e.g., normal operating conditions and abnormal operating conditions) in the cylindrical battery.

[0069] The tension testing machine 1 is set to a constant tension mode, with multiple, different constant tension values. Each of these constant tension values ​​corresponds to a different tension value experienced by a specific winding layer within a cylindrical battery. Furthermore, each of these constant tension values ​​is consistent with the tension value experienced by the winding layer within the cylindrical battery; even further, each of these constant tension values ​​is equal to the tension value experienced by the winding layer within the cylindrical battery. These multiple constant tension values ​​correspond to different radii of the steering column; that is, each constant tension value has a one-to-one correspondence with a steering column radius.

[0070] In other words, this embodiment simulates the stress states of the separator 0 in a cylindrical battery under different winding layers and different constant temperatures, and tests the performance of the separator 0 under these conditions. Specifically, the separator 0 wound on the steering column 2 with different radii is punctured under corresponding constant tension and at different constant temperatures to insert into the puncture hole 221, thereby determining the puncture strength of the separator 0 wound on the steering column 2 with different radii under corresponding constant tension and at different constant temperatures.

[0071] The following will describe a more specific implementation method.

[0072] Example 1

[0073] The first connecting end 11 of the tensile testing machine 1 is connected to the first end 01 of the diaphragm 0, and the second end 02 is connected to the second connecting end 12 by passing around the peripheral wall of the steering column 2. Part of the peripheral wall of the steering column 2 is in contact with the diaphragm 0.

[0074] The diaphragm 0 wound on the steering column 2 with different radii is stretched by the tensile testing machine 1. The different radii of the steering column 2 are matched with the vertical distance from the center axis of the winding layer to the core. The tensile testing machine 1 is set to a constant tensile force mode with multiple constant tensile force values, each different. The values ​​of the multiple constant tensile force are matched with the tensile force values ​​of the multiple winding layers in the cylindrical battery. The values ​​of the multiple constant tensile force correspond to the different radii of the steering column 2. The diaphragm 0 wound on the steering column 2 with different radii is pierced by the corresponding constant tensile force to insert into the piercing hole 221, thereby determining the piercing strength of the diaphragm 0 wound on the steering column 2 with different radii under the corresponding constant tensile force.

[0075] In Example 1, sleeves 22 with radii of 5mm, 20mm, and 40mm were selected, i.e., steering columns 2 with radii of 5mm, 20mm, and 40mm were used, with constant tensile forces of 0.03N, 0.02N, and 0.01N respectively. These were used to test the performance of the diaphragm 0 located in the innermost, middle, and outermost layers of the winding layer in a 40mm radius core. The diaphragm 0 is a ceramic-coated PE (polyethylene) base film. The test data and performance results are shown in Table 1.

[0076] Table 1:

[0077]

[0078] Example 2

[0079] The first connecting end 11 of the tensile testing machine 1 is connected to the first end 01 of the diaphragm 0, and the second end 02 is connected to the second connecting end 12 by passing around the peripheral wall of the steering column 2. Part of the peripheral wall of the steering column 2 is in contact with the diaphragm 0.

[0080] The maximum tensile force of the diaphragm 0 wound on the steering column 2 with different radii under tension is detected by the tensile testing machine 1. The different radii of the steering column 2 are matched with the vertical distance from the central axis of the winding layer to the core, thereby determining the tensile strength of the diaphragm 0 wound on the steering column 2 with the corresponding radius.

[0081] In Example 2, sleeves 22 with radii of 5mm, 20mm, and 40mm were selected, i.e., steering columns 2 with radii of 5mm, 20mm, and 40mm were used to test the performance of the diaphragm 0 in the innermost, middle, and outermost layers of the winding layer in the 40mm radius core. The diaphragm 0 is a ceramic-coated PE (polyethylene) base film. The test data and performance results are shown in Table 2.

[0082] Table 2:

[0083]

[0084] Example 3

[0085] The first connecting end 11 of the tensile testing machine 1 is connected to the first end 01 of the diaphragm 0, and the second end 02 is connected to the second connecting end 12 by passing around the peripheral wall of the steering column 2. Part of the peripheral wall of the steering column 2 is in contact with the diaphragm 0.

[0086] The diaphragm 0 wound on the steering column 2 with different radii is stretched using a tensile testing machine 1. The different radii of the steering column 2 are matched with the vertical distances from the central axis of the winding layers to the core. The tensile testing machine 1 is set to a constant tensile force mode with multiple different constant tensile force values, each matching the tensile force experienced by the winding layers in the cylindrical battery. These values ​​correspond to different radii of the steering column 2. The steering column 2 is heated using a heating assembly, and the deformation of the diaphragm 0 wound on the steering column 2 with different radii under tension is monitored to determine the pore-closing temperature and rupture temperature of the diaphragm 0 under the corresponding constant tensile force. When the deformation reaches a peak value for the first time as the heating temperature increases, the temperature corresponding to the peak value is determined as the pore-closing temperature of the diaphragm 0 wound on the steering column 2 with the corresponding radius. When the deformation reaches a trough value after the peak value as the heating temperature increases, the temperature corresponding to the trough value is determined as the rupture temperature of the diaphragm 0 wound on the steering column 2 with the corresponding radius.

[0087] In Example 3, sleeves 22 with radii of 5mm, 20mm, and 40mm were selected, i.e., steering columns 2 with radii of 5mm, 20mm, and 40mm were used, with constant tensile forces of 0.03N, 0.02N, and 0.01N respectively. These were used to test the performance of the diaphragm 0 located in the innermost, middle, and outermost layers of the winding layer in a 40mm radius core. The diaphragm 0 is a ceramic-coated PE (polyethylene) base film. The test data and performance results are shown in Table 3.

[0088] Table 3:

[0089]

[0090] As shown in Tables 1, 2 and 3, this invention simulates the separator 0 at different positions in the core to detect the real performance of the separator 0 under different states, thereby enabling a more comprehensive and accurate evaluation of the battery's performance requirements for the separator 0.

[0091] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. A device for testing the performance of a separator, the separator being used in a cylindrical battery and forming a core in the cylindrical battery, the core having multiple winding layers, the separator having a first end and a second end disposed opposite to each other along the unfolding direction, characterized in that, The detection device includes: A tensile testing machine, including a first connecting end and a second connecting end, is used to stretch the diaphragm; Steering column, including: Fixed shaft; The sleeve has multiple sleeves, each with a different radius, and can be respectively sleeved on the outer periphery of the fixed shaft, so that the steering column has multiple different radii. The multiple different radii of the steering column are respectively matched with the vertical distance from the central axis of the multiple winding layers to the core. The steering column has a central axis, which is perpendicular to the tensile force direction of the tensile testing machine. The first end is connected to the first connecting end, and the second end is connected to the second connecting end by bypassing the peripheral wall of the steering column. Part of the peripheral wall of the steering column is in contact with the diaphragm, so that the tensioning machine stretches the diaphragm when the diaphragm is wrapped around the steering column with different radii.

2. The diaphragm performance testing device as described in claim 1, characterized in that, The tensile force of the tensile testing machine is perpendicular to the vertical direction.

3. The diaphragm performance testing device as described in claim 2, characterized in that, The detection device further includes a steering shaft, and the steering column is located between the tensile testing machine and the steering shaft along a first direction. The steering shaft includes a first steering shaft and a second steering shaft. The steering column is located between the first steering shaft and the second steering shaft along the vertical direction. The first connecting end and the second connecting end are arranged opposite each other along the vertical direction. The first end is connected to the first connecting end, and the second end passes through the peripheral wall of the first steering shaft, the peripheral wall of the steering column, and the peripheral wall of the second steering shaft in sequence before connecting to the second connecting end. The first connecting end has a first connecting position connected to the first end, the second connecting end has a second connecting position connected to the second end, the first steering shaft has a first top contact position and a first bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the second steering shaft has a second top contact position and a second bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the steering column has a third top contact position and a third bottom contact position that are in contact with the diaphragm and are arranged opposite each other along the vertical direction, the first connecting position and the first top contact position are at the same height along the vertical direction, the first bottom contact position and the third top contact position are at the same height along the vertical direction, the third bottom contact position and the second top contact position are at the same height along the vertical direction, the second bottom contact position and the second connecting position are at the same height along the vertical direction, and the first direction is parallel to the tension direction of the tensioning machine.

4. The diaphragm performance testing device as described in claim 3, characterized in that, The direction of the first connection position toward the first top contact position is parallel to and opposite to the direction of the first bottom contact position toward the third top contact position, and the direction of the third bottom contact position toward the second top contact position is parallel to and opposite to the direction of the second bottom contact position toward the second connection position.

5. The diaphragm performance testing device as described in claim 1, characterized in that, The fixed shaft is equipped with a heating component, which is used to heat the sleeve through the fixed shaft, thereby heating the diaphragm wrapped around the peripheral wall of the sleeve.

6. The diaphragm performance testing device as described in claim 1, characterized in that, The detection device includes a puncture intensity detection component, which is used to detect the puncture intensity of the diaphragm. The puncture intensity detection component includes a puncture needle, and the peripheral wall of the sleeve is provided with a puncture hole, which is used for the puncture needle to puncture the diaphragm and then insert itself.

7. The diaphragm performance testing device as described in claim 1, characterized in that, Multiple sleeves are coaxially sleeved on the fixed shaft, and adjacent sleeves are detachably connected.

8. A method for testing the performance of a diaphragm, characterized in that, The detection method, using the detection apparatus as described in any one of claims 1-7, comprises the following steps: The first connecting end is connected to the first end of the diaphragm, and the second end is connected to the second connecting end by bypassing the peripheral wall of the steering column, with part of the peripheral wall of the steering column in contact with the diaphragm; The diaphragm, which is wound around the steering column with different radii, is stretched using the tensile testing machine to detect its performance under tension.

9. The method for testing diaphragm performance as described in claim 8, characterized in that, The maximum tensile force of the diaphragm wound on the steering column with different radii under tension is obtained by the tensile testing machine, thereby determining the tensile strength of the diaphragm wound on the steering column with the corresponding radius.

10. The method for testing the membrane performance as described in claim 8, characterized in that, The fixed shaft is equipped with a heating assembly, which is used to heat the sleeve through the fixed shaft, thereby heating the diaphragm wound around the side wall of the sleeve. The detection method includes: adjusting the heating temperature of the heating assembly, and stretching the diaphragm wound on the steering column with different radii at different heating temperatures using the tensile testing machine, thereby determining the tensile strength of the diaphragm wound on the steering column with different radii at different heating temperatures. And / or, the detection method includes: setting the heating rate of the heating component to 1~5℃ / min, setting the tensile testing machine to a constant tensile force mode, wherein the constant tensile force has multiple values, the multiple constant tensile force values ​​are different, the multiple constant tensile force values ​​are respectively matched with the tensile force values ​​of the multiple winding layers in the cylindrical battery, the multiple constant tensile force values ​​respectively correspond to multiple different radii of the steering column, and monitoring the change of the deformation of the separator wound on the steering column with different radii under the corresponding constant tensile force with the change of heating temperature, thereby determining the pore-closing temperature and the membrane-breaking temperature of the separator on the steering column with different radii under the corresponding constant tensile force; the pore-closing temperature is the temperature corresponding to the peak value of the deformation as the heating temperature increases, and the membrane-breaking temperature is the temperature corresponding to the valley value after the peak value of the deformation as the heating temperature increases.

11. The method for testing the membrane performance as described in claim 10, characterized in that, The detection device includes a puncture intensity detection component, which is used to detect the puncture intensity of the diaphragm. The puncture intensity detection component includes a puncture needle, and the peripheral wall of the sleeve is provided with a puncture hole, which is used for the puncture needle to puncture the diaphragm and then insert itself. The detection method includes: adjusting the heating temperature of the heating component, setting the tensile testing machine to the constant tensile force mode, and using the puncture needle to puncture the diaphragm wound on the steering column with different radii under the corresponding constant tensile force and different heating temperatures to insert into the puncture hole, thereby determining the penetration strength of the diaphragm wound on the steering column with different radii under the corresponding constant tensile force and different heating temperatures.

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