A lithium battery separator pore closure and puncture temperature testing device and system

Abstract

The utility model relates to the technical field of lithium battery diaphragm performance test, more specifically, relate to a kind of lithium battery diaphragm closed pore and membrane breaking temperature testing device and system.Testing device includes at least two groups of testing mechanism, and the diaphragm to be tested is clamped between two groups of the testing mechanism, and the testing mechanism includes electrolytic component, temperature measuring piece, and positioning mechanism is equipped on the electrolytic component, and the temperature measuring piece is installed on the electrolytic component by the positioning mechanism.The installation position of temperature measuring piece is positioned by positioning mechanism, so that the depth of temperature measuring piece is kept consistent each time, so as to ensure that temperature measuring piece keeps consistent each time temperature measuring point, effectively avoid the detection error caused by temperature measuring point inconsistency, improve the precision of data acquisition.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery separator performance testing technology, and more specifically, to a lithium battery separator pore closure and rupture temperature testing device and system. Background Technology

[0002] The lithium-ion battery separator is one of the key internal components of a battery. Its main function is to separate the positive and negative electrodes, preventing short circuits caused by contact between them. It also allows electrolyte ions to pass through. Its performance determines the battery's interface structure and internal resistance, directly affecting its capacity, cycle life, and safety performance. High-strength, thin-film polyolefin porous materials are generally used. To improve the performance of polyolefin separators and meet the technical requirements of next-generation lithium-ion batteries, such as safety, long lifespan, and diverse battery structures, ceramic-coated separators and polymer-coated separators have emerged. Low pore size and high rupture temperature are the main research directions for separators. Lower pore size can promptly shut off the current when the battery temperature rises to a certain level, preventing further temperature increases; higher rupture temperature ensures battery safety and prevents the risk of fire and explosion due to short circuits between the positive and negative electrodes.

[0003] Existing lithium battery separator pore and membrane rupture testing devices are prone to positional deviations when replacing temperature sensors. This results in different temperature measurement points between the replaced and original sensors, leading to inconsistent temperature data. This inconsistency is particularly problematic when testing separators of the same batch or model, as it affects subsequent data analysis and ultimately impacts the assessment of separator performance. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies where the installation position of the temperature measuring element is prone to deviation when replacing the element, resulting in inconsistent temperature data before and after testing. This invention provides a lithium battery separator pore closure and rupture temperature testing device and system, which effectively reduces the installation error of the temperature measuring element, ensures the consistency of the temperature measuring points, and thus improves the testing accuracy.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0006] A lithium battery separator pore closure and rupture temperature testing device is provided, comprising at least two sets of testing mechanisms, with the separator to be tested clamped between the two sets of testing mechanisms. Each testing mechanism includes an electrolysis component and a temperature measuring element for detecting the temperature of the separator to be tested. A positioning mechanism is provided on the electrolysis component, and the temperature measuring element is installed on the electrolysis component through the positioning mechanism.

[0007] In this invention, the diaphragm under test is sealed between two sets of testing mechanisms. The electrolyte in the electrolysis assembly on the left side of the diaphragm immerses the left surface of the diaphragm, and the temperature sensor on the left side is used to test the temperature on the left side of the diaphragm. Similarly, the electrolyte in the electrolysis assembly on the right side immerses the right surface of the diaphragm, and the temperature sensor on the right side is used to test the temperature on the right side of the diaphragm. This invention incorporates a positioning mechanism on the electrolysis assembly to position the temperature sensor, ensuring consistent insertion depth each time. This guarantees consistent temperature measurement points, effectively preventing inconsistencies in temperature data for the same batch or model of diaphragm due to inconsistent measurement points. It also avoids data acquisition errors affecting the assessment of diaphragm performance during subsequent data analysis, thus improving the accuracy of data acquisition.

[0008] Furthermore, the electrolysis assembly includes an electrolytic cell and a storage tank connected to the electrolytic cell. The end of the temperature measuring element extends into the storage tank through the inner cavity of the electrolytic cell. One temperature measuring element extends from the inner cavity of one electrolytic cell into its storage tank to detect the temperature on the left side of the diaphragm under test, while the other temperature measuring element extends from the inner cavity of another electrolytic cell into its storage tank to detect the temperature on the right side of the diaphragm under test.

[0009] Furthermore, the two surfaces of the diaphragm to be tested are sealed between the openings of the two sets of liquid storage tanks. The diaphragm to be tested is sealed between the openings of the two sets of liquid storage tanks, with the electrolyte in one liquid storage tank immersing the left surface of the diaphragm to be tested, and the electrolyte in the other liquid storage tank immersing the right surface of the diaphragm to be tested.

[0010] Furthermore, the temperature measuring element is detachably connected to the positioning mechanism. This detachable connection facilitates the replacement of the temperature measuring element.

[0011] Furthermore, a positioning sleeve is fitted onto the temperature measuring element. The positioning sleeve allows for the positioning of the temperature measuring element's installation height, ensuring that the installation height remains consistent each time it is installed.

[0012] Furthermore, the positioning mechanism is provided with an arc-shaped groove, and an arc-shaped clamping plate is detachably provided with the positioning mechanism. The temperature measuring element is clamped between the arc-shaped groove and the arc-shaped clamping plate. During installation, the temperature measuring element is first placed in the arc-shaped groove of the positioning mechanism to achieve horizontal positioning of the temperature measuring element. Then, the vertical position of the temperature measuring element is positioned by the positioning sleeve. Next, the arc-shaped bend of the arc-shaped clamping plate is clamped onto the positioning sleeve and pressed tightly. The arc-shaped clamping plate is then fixed to the positioning mechanism by bolts, completing the installation and fixing of the temperature measuring element.

[0013] Furthermore, the two sets of positioning mechanisms are arranged opposite to each other on the two sets of electrolysis components, and the two sets of positioning mechanisms are arranged adjacent to each other. With the two sets of positioning mechanisms arranged opposite to each other, both the two sets of positioning mechanisms and the two sets of temperature measuring elements are concentrated in the middle of the entire testing device, leaving sufficient space on both sides of the device to facilitate the installation or removal of temperature measuring elements by the operator, and also to facilitate the operator in holding electrolyte, etc.

[0014] Furthermore, the positioning mechanism includes a positioning block; the temperature measuring element includes a thermocouple or a T-type thermocouple.

[0015] Furthermore, it also includes a quick-connect plug. The electrolysis assembly has a wire interface, and the quick-connect plug is electrically connected to both the wire interface and the temperature sensing element. The quick-connect plug is used for connecting to external data acquisition instruments, etc. In use, it directly connects to the external data acquisition instrument via the quick-connect plug, making operation simple and quick.

[0016] Furthermore, it also includes a base, wherein one set of the electrolytic components is fixedly connected to the base, and the other set of the electrolytic components is slidably connected to the base. In use, the distance between the openings of the two storage tanks is adjusted by sliding one set of electrolytic components. When a diaphragm to be tested needs to be installed, the electrolytic components are slid to move away from the other electrolytic component, creating a certain installation space between the two storage tanks. The diaphragm to be tested is then placed at the opening of one of the storage tanks, and the electrolytic components are gradually slid closer to the other electrolytic component until the diaphragm to be tested is sealed and pressed between the two storage tanks.

[0017] Furthermore, it also includes an adjustment mechanism that converts rotation into linear motion. The end of the adjustment mechanism has a hand-tightening adjustment section, and the center of the hand-tightening adjustment section has a hexagonal slot. The adjustment mechanism is mounted on a base and connected to a slidable set of electrolytic components. Rotating the adjustment mechanism drives the electrolytic components to achieve linear motion. After the diaphragm to be tested is placed, the adjustment mechanism can be manually rotated. To ensure that the clamping force is the same each time, a torque wrench can be connected to the hexagonal slot for adjustment, thus ensuring that the clamping force on both sides of the diaphragm to be tested is consistent during each test.

[0018] This utility model also provides a lithium battery separator pore closure and rupture temperature testing system, including the lithium battery separator pore closure and rupture temperature testing device described above, a first data acquisition instrument capable of acquiring resistance, a second data acquisition instrument capable of acquiring temperature, and a heating device; the testing device is installed inside the heating device; the second data acquisition instrument is electrically connected to the temperature measuring element; the first data acquisition instrument is electrically connected to the electrolyte contained in the electrolysis assembly.

[0019] In this invention, a first data acquisition instrument collects the resistance values ​​on both sides of the diaphragm under test, and a second data acquisition instrument collects the temperature values ​​on both sides of the diaphragm under test. At the start of the test, the first and second data acquisition instruments collect resistance and temperature data in real time. When the resistance value is found to change from low to high and then back to low, that is, when the diaphragm under test has gone through the entire process of pore closure and membrane rupture, the test is stopped, the resistance and temperature data are exported, and data analysis and processing are performed to obtain the pore closure and membrane rupture temperatures of the diaphragm under test.

[0020] Furthermore, it also includes a host computer, through which the first data acquisition instrument, the second data acquisition instrument, and the heating device are all communicatively connected. This invention achieves unified control via the host computer, allowing for the start and stop of each device without requiring separate clicks on the start buttons of the first and second data acquisition instruments. This ensures that the data collected by both devices originates from the same starting point. The host computer's parameter setting interface allows users to configure acquisition items such as temperature and resistance. The temperature dropdown menu allows selection of thermocouple models, etc. The global parameter interface allows input of the diaphragm model under test, sampling interval, and whether to set a timed start and stop. Users can set a stop interval or manually stop the test. The raw test data can be saved to a specified path and is automatically saved after the test. Data can also be manually exported for analysis of pore closure temperature and membrane rupture temperature.

[0021] Furthermore, the first data acquisition instrument is an LCR bridge. This invention uses an LCR bridge to detect the resistance on both sides of the membrane under test. Its internal signal is an AC signal. AC current can eliminate the influence of concentration polarization of the electrolyte during use, thus simplifying the variable to only detect the ionic resistance of the membrane. That is, it only analyzes the change in resistance of ions passing through the membrane under test with temperature to determine the pore closure temperature and membrane rupture temperature of the membrane, thereby improving the detection accuracy.

[0022] Compared with the prior art, the beneficial effects of this utility model are:

[0023] This utility model discloses a lithium battery separator pore closure and rupture temperature testing device and system. By positioning the installation position of the temperature measuring element through a positioning mechanism, the insertion depth of the temperature measuring element is kept consistent each time, thereby ensuring that the temperature measuring point of the temperature measuring element is consistent each time. This effectively avoids the problem of inconsistent temperature data before and after the same batch or model of separator due to inconsistent temperature measuring points, and avoids the impact of data acquisition errors on the judgment of separator performance during subsequent data analysis, thus improving the accuracy of data acquisition. Attached Figure Description

[0024] Figure 1 This is a first-view structural diagram of the test device in one embodiment;

[0025] Figure 2 This is a second-view structural diagram of the test device in one embodiment;

[0026] Figure 3 This is a schematic diagram of the structure of the first or second testing mechanism in one embodiment;

[0027] Figure 4 This is a schematic diagram of the internal structure of the first or second testing mechanism in one embodiment;

[0028] Figure 5 This is a schematic diagram showing the installation of the first or second temperature measuring element in one embodiment;

[0029] Figure 6 This is a schematic diagram of the connection relationship of the test system in one embodiment.

[0030] In the attached diagram: 1. First testing mechanism; 11. First electrolysis assembly; 12. First temperature measuring element; 13. First liquid storage tank; 14. First positioning mechanism; 15. First positioning sleeve; 16. First wire interface; 17. First vent hole; 18. First arc-shaped clamp; 2. Second testing mechanism; 21. Second electrolysis assembly; 22. Second temperature measuring element; 23. Second liquid storage tank; 24. Second positioning mechanism; 25. Second positioning sleeve; 26. Second wire interface; 27. Second vent hole; 28. Second arc-shaped clamp; 3. Base; 31. Slide rail; 4. Adjustment mechanism; 41. Hand-tight adjustment part. Detailed Implementation

[0031] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the present invention. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0032] In the accompanying drawings of this utility model, the same or similar reference numerals correspond to the same or similar components. In the description of this utility model, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this utility model. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0033] Example 1

[0034] This embodiment is a first embodiment of a lithium battery separator pore closure and rupture temperature testing device, such as... Figures 1 to 5 As shown, the system includes a base 3, a first testing mechanism 1, and a second testing mechanism 2. The first testing mechanism 1 includes a first electrolysis assembly 11 and a first temperature measuring element 12. The first electrolysis assembly 11 has a first electrolytic cell and a first liquid storage tank 13 connected to the first electrolytic cell. The end of the first temperature measuring element 12 extends into the first liquid storage tank 13 through the inner cavity of the first electrolysis assembly 11. The second testing mechanism 2 includes a second electrolysis assembly 21 and a second temperature measuring element 22. The second electrolysis assembly 21 includes a second electrolytic cell and a second liquid storage tank 23 connected to the second electrolytic cell. The end of the temperature measuring element 22 extends into the second liquid storage tank 23 through the inner cavity of the second electrolysis assembly 21; and the two surfaces of the diaphragm to be tested are sealed between the opening of the first liquid storage tank 13 and the opening of the second liquid storage tank 23; the first electrolysis assembly is provided with a first positioning mechanism 14 for positioning the installation position of the first temperature measuring element 12, and the second electrolysis assembly is provided with a second positioning mechanism 24 for positioning the installation position of the second temperature measuring element 22; the first temperature measuring element 12 is detachably connected to the first positioning mechanism 14; the second temperature measuring element 22 is detachably connected to the second positioning mechanism 24.

[0035] like Figure 2 As shown, the first electrolysis component 11 is fixedly connected to the base 3, and the second electrolysis component 21 is slidably connected to the base 3. A slide rail 31 is provided on the base 3, and an insulating base is connected to the bottom of the second electrolysis component 21. A groove corresponding to the slide rail 31 is provided at the bottom of the base. The sliding connection between the second electrolyzer container and the base 3 is realized through the cooperation of the groove and the slide rail 31. The installation heights of the first electrolysis component 11 and the second electrolysis component 21 are consistent, as are the heights of the first liquid storage tank 13 and the second liquid storage tank 23. During use, the distance between the openings of the first liquid storage tank 13 and the second liquid storage tank 23 is adjusted by sliding the second electrolysis component 21. When a diaphragm to be tested needs to be installed, the second electrolysis component 21 is slid to move it away from the first electrolysis component 11, creating a certain installation space between the first liquid storage tank 13 and the second liquid storage tank 23. The diaphragm to be tested is then placed at the opening of the first liquid storage tank 13, and the second electrolysis component 21 is slid closer to the first electrolysis component 11 until the diaphragm to be tested is sealed and pressed between the first liquid storage tank 13 and the second liquid storage tank 23.

[0036] like Figure 1 and Figure 2As shown, the first positioning mechanism 14 and the second positioning mechanism 24 are arranged opposite to each other, with the first temperature measuring element 12 located on the side of the first positioning mechanism 14 facing away from the second positioning mechanism 24, and the second temperature measuring element 22 located on the side of the second positioning mechanism 24 facing away from the first positioning mechanism 14. The first positioning mechanism 14 and the second positioning mechanism 24 are arranged opposite to each other, so that the first positioning mechanism 14 and the second positioning mechanism 24, as well as the first temperature measuring element 12 and the second temperature measuring element 22, are all concentrated in the middle of the entire testing device. Sufficient space is available on both sides of the device, facilitating the installation or removal of the first temperature measuring element 12 and the second temperature measuring element 22 by the operator, and also facilitating the handling of electrolytes, etc.

[0037] like Figures 2 to 5 As shown, a first positioning sleeve 15 is fitted onto the first temperature measuring element 12, and a second positioning sleeve 25 is fitted onto the second temperature measuring element 22. The first positioning sleeve 15 and the second positioning sleeve 25 allow for positioning of the first temperature measuring element 12 and the second temperature measuring element 22 at the correct installation height, ensuring consistent installation height each time. Furthermore, the placement of the first positioning sleeve 15 and the second positioning sleeve 25 increases the friction between the first positioning mechanism 14 and the second positioning mechanism 24, thereby improving the stability of the temperature measuring element installation to a certain extent.

[0038] like Figure 5 As shown, a first arc-shaped groove is provided on the first positioning mechanism 14, and a first arc-shaped clamping plate 18 is detachably provided with the first positioning mechanism 14. The first temperature measuring element 12 is clamped between the first arc-shaped groove and the first arc-shaped clamping plate 18. A second arc-shaped groove is provided on the second positioning mechanism 24, and a second arc-shaped clamping plate 28 is detachably provided with the second positioning mechanism 24. The second temperature measuring element 22 is clamped between the second arc-shaped groove and the second arc-shaped clamping plate 28. The first arc-shaped clamping plate 18 and the second arc-shaped clamping plate 28 are arc-shaped bends in the middle, and the two ends are flat plates with screw holes. Correspondingly, screw holes are also provided on the first positioning mechanism 14 and the second positioning mechanism 24 to facilitate installation. In this embodiment, the ends of both the first temperature measuring element 12 and the second temperature measuring element 22 are bent at 90°, extending into the first liquid storage tank 13 and the second liquid storage tank 23 through the bent portions. During installation, the first temperature measuring element 12 is first placed in the first arc-shaped groove of the first positioning mechanism 14 to achieve horizontal positioning of the first temperature measuring element 12, that is, to ensure that the depth of the bent portion inserted into the first liquid storage tank 13 remains consistent each time. Then, the first positioning sleeve 15 positions the first temperature measuring element 12 vertically. Finally, the arc-shaped bent portion of the first arc-shaped clamping plate 18 is clamped onto the first positioning sleeve 15 and pressed tightly. The first arc-shaped clamping plate 18 and the first positioning mechanism 14 are fixed together by bolts, thus completing the installation and fixing of the first temperature measuring element 12. The installation and positioning method of the second temperature measuring element 22 is the same as that of the first temperature measuring element 12.

[0039] like Figure 3 and Figure 4As shown, the bottom of the first storage tank 13 is connected to the inner cavity of the first electrolytic cell, and the bottom of the second storage tank 23 is connected to the second electrolytic cell through pipes to ensure that the electrolyte can flow into the first storage tank 13 and the second storage tank 23. The side walls of the first storage tank 13 and the second storage tank 23 are respectively provided with a first vent hole 17 and a second vent hole 27 to balance the pressure difference between the first electrolytic cell and the first storage tank 13, and between the second electrolytic cell and the second storage tank 23, to ensure that the electrolyte can fill the entire first storage tank 13 and the second storage tank 23, thereby ensuring that both sides of the diaphragm to be tested can be completely immersed in the electrolyte.

[0040] In this embodiment, to avoid leakage, the first liquid storage tank 13 is integrally formed with the first electrolysis component 11; the second liquid storage tank 23 is integrally formed with the second electrolysis component 21.

[0041] like Figure 2 As shown, the opening of the first liquid storage tank 13 is provided with a first gasket, and the opening of the second liquid storage tank 23 is provided with a second gasket. The diaphragm seal to be tested is sandwiched between the first gasket and the second gasket. The sealing performance can be effectively improved by the first gasket and the second gasket.

[0042] In addition, in this embodiment, both the first temperature measuring element 12 and the second temperature measuring element 22 are T-type thermocouples, with a temperature acquisition accuracy within 0.5℃ and a resolution of 0.1℃. The resistance measurement range is above 1TΩ, which can collect the resistance change of the diaphragm in real time from the beginning of closure, to complete closure, to rupture.

[0043] like Figure 2 and Figure 4 As shown, a first wire interface 16 and a second wire interface 26 are respectively provided on the first electrolysis component 11 and the second electrolysis component 21. Fastening bolts are provided at both the first wire interface 16 and the second wire interface 26 to facilitate wiring. In this embodiment, the first wire interface 16 and the second wire interface 26 are respectively located at the top of the first electrolysis component 11 and the second electrolysis component 21, which can avoid the impact of electrolyte corrosion on the resistance detection.

[0044] In this embodiment, the first electrolytic component 11 and the second electrolytic component 21 are made of conductive metal, preferably copper. During testing, the first electrolytic component 11 and the second electrolytic component 21 can be directly used as conductors (electrodes) to test the resistance. The first wire interface 16 and the second wire interface 26 can be a screw hole with a fastening bolt installed. When wiring, the wire can be directly wound around the fastening bolt. The base 3, the first positioning mechanism 14, the second positioning mechanism 24, and the base located on the second electrolytic component 21 are all made of high-temperature resistant and insulating materials. The first washer and the second washer are made of insulating materials. It should be noted that using the first electrolytic component 11 and the second electrolytic component 21 directly as conductors is only one implementation method. Other methods can also be used. For example, the first electrolytic component 11 and the second electrolytic component 21 can be made of insulating materials, and the test electrode can be directly inserted into the electrolyte when testing the resistance.

[0045] In this invention, the diaphragm to be tested is sealed between the opening of the first storage tank 13 and the opening of the second storage tank 23. The electrolyte in the first storage tank 13 immerses the left side surface of the diaphragm to be tested, and the electrolyte in the second storage tank 23 immerses the right side surface of the diaphragm to be tested. The first temperature measuring element 12 extends from the inner cavity of the first electrolytic cell into the first storage tank 13 to detect the temperature on the left side of the diaphragm to be tested, and the second temperature measuring element 22 extends from the inner cavity of the second electrolytic cell into the second storage tank 23 to detect the temperature on the right side of the diaphragm to be tested. In this embodiment, a first positioning mechanism 14 and a second positioning mechanism 2 are respectively provided on the first electrolysis assembly 11 and the second electrolysis assembly 21. 4. The first positioning mechanism 14 positions the first temperature measuring element 12, ensuring that the insertion depth of the first temperature measuring element 12 remains consistent each time. The first positioning sleeve 15 positions the installation height of the first temperature measuring element 12, ensuring that the temperature measuring point of the first temperature measuring element 12 remains consistent each time. The second positioning mechanism 24 positions the second temperature measuring element 22, and the second positioning sleeve 25 positions the installation height of the second temperature measuring element 22, ensuring that the insertion depth of the second temperature measuring element 22 remains consistent each time. This ensures that the temperature measuring point of the second temperature measuring element 22 remains consistent each time, effectively avoiding detection errors caused by inconsistent temperature measuring points and effectively improving the accuracy of data lake acquisition.

[0046] Example 2

[0047] This embodiment is a second embodiment of a lithium battery separator pore closure and rupture temperature testing device. The other structures of this embodiment are the same as in the first embodiment, except that a quick-connect plug is also provided. The quick-connect plug is electrically connected to the first wire interface 16, the second wire interface 26, the first temperature measuring element 12, and the second temperature measuring element 22, respectively. The quick-connect plug is used for connection to external data acquisition instruments, etc. In use, it is directly connected to the external data acquisition instrument via the quick-connect plug, making operation simple and quick.

[0048] During testing, the testing device needs to be placed entirely inside the heating device's housing, and the temperature of the electrolyte is controlled by the heating device. Since the testing device provided in this embodiment is equipped with a quick-connect plug, a corresponding socket is provided on the heating device's housing to facilitate the use of the quick-connect plug.

[0049] Example 3

[0050] This embodiment is a third embodiment of a lithium battery separator pore-closure and rupture temperature testing device. The other structures of this embodiment are the same as in embodiment one, except that, in this embodiment, as... Figure 1 and Figure 2 As shown, it also includes an adjustment mechanism 4 that converts rotation into linear motion. The end of the adjustment mechanism 4 has a hand-tightening adjustment part 41, and a hexagonal slot is provided in the middle of the hand-tightening adjustment part 41. The adjustment mechanism 4 is mounted on the base 3 and connected to the second electrolysis assembly 21. Rotating the adjustment mechanism 4 drives the second electrolysis assembly 21 to achieve linear motion. After the diaphragm to be tested is placed, the adjustment mechanism can be manually rotated. To ensure that the clamping force is the same each time, a torque wrench can be used for adjustment, thereby ensuring that the clamping force on both sides of the diaphragm to be tested is consistent during each test.

[0051] like Figure 2 As shown, the adjusting mechanism 4 is an adjusting screw. A support block is provided on the base 3, and the support block has a threaded through hole. The adjusting screw passes through the threaded through hole and is threadedly connected to the support block. One end of the adjusting screw is rotatably connected to the second electrolysis component 21, and a hand-tightening adjusting part 41 is provided at the other end of the adjusting screw. A hexagonal slot is located in the middle of the hand-tightening adjusting part 41 and is coaxially arranged with the adjusting screw. It should be noted that the adjusting mechanism 4 can also be a gear-rack mechanism or other mechanisms that can convert rotation into linear motion.

[0052] Example 4

[0053] This embodiment is a first embodiment of a lithium battery separator pore-closure and rupture temperature testing system, including the lithium battery separator pore-closure and rupture temperature testing device described in any one of embodiments one to three, a first data acquisition instrument capable of acquiring resistance, a second data acquisition instrument capable of acquiring temperature, and a heating device; the testing device is installed inside the heating device; the second data acquisition instrument is electrically connected to the first temperature measuring element 12 and the second temperature measuring element 22 respectively; the first data acquisition instrument is electrically connected to the electrolyte contained in the first electrolytic assembly 11 and the second electrolytic assembly 21 respectively. The first data acquisition instrument acquires the resistance values ​​on both sides of the separator under test, and the second data acquisition instrument acquires the temperature values ​​on both sides of the separator under test; at the start of the test, the first and second data acquisition instruments acquire resistance and temperature data in real time. When the resistance value is found to change from low to high and then back to low, that is, when the separator under test has undergone the entire process of pore closure and rupture, the test is stopped, the resistance and temperature data are exported, and data analysis and processing are performed to obtain the pore-closure and rupture temperatures of the separator under test.

[0054] In this embodiment, the first data acquisition instrument is an LCR bridge. The high-voltage end of the LCR bridge is connected to the first wire interface 16, and the low-voltage end of the LCR bridge is connected to the second wire interface 26. This invention uses an LCR bridge to detect the resistance on both sides of the membrane under test. Its internal signal is an AC signal. AC current can eliminate the influence of concentration polarization of the electrolyte during use, thus simplifying the variable to only detect the ionic resistance of the membrane. That is, it only analyzes the change in resistance of ions passing through the membrane under test with temperature to determine the pore closure temperature and membrane rupture temperature of the membrane, thereby improving the detection accuracy.

[0055] In addition, the heating device has a mounting plate inside the chamber, on which the testing device is placed. Heating tubes are installed at the top and bottom of the heating device to ensure uniform heating. An adjustable exhaust vent is also provided at the top of the chamber.

[0056] Example 5

[0057] This embodiment is a second embodiment of a lithium battery separator pore-closure and rupture temperature testing system. This embodiment is similar to embodiment four, except that, as shown in the following... Figure 6As shown, in this embodiment, a host computer is also included. The first data acquisition instrument, the second data acquisition instrument, and the heating device are all communicatively connected to the host computer. This utility model achieves unified control via the host computer, allowing the host computer to control the start and stop of each device without needing to click the start buttons of the first and second data acquisition instruments separately to begin the test. This ensures that the starting point of the data collected by the two devices is consistent. The host computer parameter setting interface allows setting the acquisition items, such as temperature and resistance. In the temperature drop-down parameters, the model of the temperature sensing element can be selected; for the LCR bridge, test items such as inductance (L), capacitance (C), and resistance (R) can be selected, and the sampling frequency (usually 1kHz) and level disturbance can be set in the drop-down parameters. In the global parameter interface, the model of the diaphragm to be tested, the sampling interval time, and whether to start and stop timed are allowed can be entered. The stop can be set at a certain interval or manually stopped. The raw test data can be saved to a specified path and is automatically saved after the test. Data can also be manually exported for analysis of pore temperature and membrane rupture temperature. The host computer's main interface is divided into several parts, including data display, parameter settings, test start and stop, and communication connection. After the device is connected, test parameters can be set, the test can be started, and test data can be recorded in real time. After the test stops, the data can be exported, and the data storage address can be managed through the log management interface for later retrieval.

[0058] Test steps:

[0059] 1. Cut three diaphragms, approximately 5cm x 5cm in size, to be tested using ceramic scissors. Immerse the diaphragms in the electrolyte solution until fully wetted. Take out one diaphragm and attach the first and second washers tightly to both sides of the diaphragm, with the first washer firmly against the opening of the first storage tank 13. Manually rotate the adjusting mechanism 4 to gradually bring the second electrolytic component 21 closer to the first electrolytic component 11, so that the diaphragm is positioned between the first and second storage tanks 13 and 23. Then tighten the tension with a torque wrench. Add appropriate amounts of electrolyte to the first and second electrolytic cells respectively. Place the entire testing device into the heating device's housing. Insert the quick-connect plug into the housing's socket to connect to the first and second data acquisition instruments, and close the housing door.

[0060] 2. Power on the first data acquisition instrument, the second data acquisition instrument, and the heating device. Confirm the connection status of the equipment on the host computer, set the test parameters, and start the test. The test frequency is usually 1kHz, the sampling interval is 1s, the temperature of the chamber is 180℃, and the heating rate is 5℃ / min. For diaphragms with excessively high rupture temperature, the maximum temperature can be adjusted appropriately.

[0061] 3. Begin testing, collecting temperature and internal resistance data in real time. Once the resistance value changes from low to high and then back to low, indicating that the diaphragm has undergone the entire process of pore closure and rupture, the test can be stopped and the data exported.

[0062] 4. Data analysis: The exported data includes two columns of temperature (corresponding to the temperatures on the left and right sides of the diaphragm, respectively) and one column of internal resistance. The average value of the two temperature columns is used as the horizontal axis and the internal resistance is used as the vertical axis to obtain the values ​​of the pore closure temperature and the membrane rupture temperature.

[0063] In the specific implementation of the above embodiments, the technical features can be combined in any non-contradictory way. For the sake of brevity, not all possible combinations of the above technical features are described. However, as long as the combination of these technical features is not contradictory, it should be considered to be within the scope of this specification.

[0064] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating this utility model, and are not intended to limit the implementation of this utility model. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. A device for testing the pore-closure and rupture temperature of a lithium battery separator, characterized in that, It includes at least two sets of testing mechanisms, with the diaphragm to be tested clamped between the two sets of testing mechanisms. Each testing mechanism includes an electrolysis component and a temperature measuring element. A positioning mechanism is provided on the electrolysis component, and the temperature measuring element is installed on the electrolysis component through the positioning mechanism.

2. The lithium battery separator pore closure and rupture temperature testing device according to claim 1, characterized in that, The electrolysis assembly includes an electrolysis cell and a liquid storage tank connected to the electrolysis cell. The end of the temperature measuring element extends into the liquid storage tank through the inner cavity of the electrolysis cell.

3. The lithium battery separator pore closure and rupture temperature testing device according to claim 2, characterized in that, The two surfaces of the diaphragm to be tested are sealed between the openings of the two sets of liquid storage tanks.

4. The lithium battery separator pore closure and rupture temperature testing device according to claim 1, characterized in that, The temperature measuring element is detachably connected to the positioning mechanism.

5. The lithium battery separator pore closure and rupture temperature testing device according to claim 4, characterized in that, A positioning sleeve is fitted onto the temperature measuring element.

6. The lithium battery separator pore closure and rupture temperature testing device according to claim 5, characterized in that, The positioning mechanism is provided with an arc-shaped groove, and an arc-shaped clamping plate is detachably provided with the positioning mechanism. The temperature measuring element is clamped between the arc-shaped groove and the arc-shaped clamping plate.

7. The lithium battery separator pore closure and rupture temperature testing device according to claim 5, characterized in that, The two sets of positioning mechanisms are arranged opposite to each other on the two sets of electrolysis components, and the two sets of positioning mechanisms are arranged adjacent to each other.

8. The lithium battery separator pore-closure and rupture temperature testing device according to any one of claims 1 to 7, characterized in that, The positioning mechanism includes a positioning block; the temperature measuring element includes a thermocouple and a T-type thermocouple.

9. The lithium battery separator pore-closure and rupture temperature testing device according to any one of claims 1 to 7, characterized in that, It also includes a quick plug, and the electrolysis assembly has a wire interface, the quick plug being electrically connected to the wire interface and the temperature measuring element respectively.

10. The lithium battery separator pore-closure and rupture temperature testing device according to any one of claims 1 to 7, characterized in that, It also includes a base, wherein one set of the electrolysis components is fixedly connected to the base, and the other set of electrolysis components is slidably connected to the base.

11. The lithium battery separator pore closure and rupture temperature testing device according to claim 10, characterized in that, It also includes an adjustment mechanism that can convert rotation into linear motion, wherein the end of the adjustment mechanism is provided with a hand-tightening adjustment part, and the middle of the hand-tightening adjustment part is provided with a hexagonal groove.

12. A lithium battery separator pore closure and rupture temperature testing system, characterized in that, The device includes a lithium battery separator pore and rupture temperature testing device as described in any one of claims 1 to 11, a first data acquisition instrument capable of acquiring resistance, a second data acquisition instrument capable of acquiring temperature, and a heating device; the testing device is installed inside the heating device; the second data acquisition instrument is electrically connected to the temperature measuring element; and the first data acquisition instrument is electrically connected to the electrolyte contained in the electrolysis assembly.

13. The lithium battery separator pore closure and rupture temperature testing system according to claim 12, characterized in that, It also includes a host computer, and the first data acquisition instrument, the second data acquisition instrument, and the heating device are all communicatively connected to the host computer.

14. The lithium battery separator pore closure and rupture temperature testing system according to claim 12, characterized in that, The first data acquisition instrument is an LCR bridge.

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