阅读说明：本技术 聚烯烃微孔膜闭孔破膜温度测试专用夹具及测试装置和方法 (Special fixture for polyolefin microporous membrane closed cell rupture temperature test, and test device and method ) 是由 王志豪 陶晶 张�雄 周杨庚 王思双 欧阳玲萍 陈瀚 于 2020-05-15 设计创作，主要内容包括：本发明公开了一种聚烯烃微孔膜闭孔破膜温度测试专用夹具及测试装置和方法。所述专用夹具包括上夹持板、下夹持板、上电极片和下电极片,所述上夹持板和下夹持板相对设置,所述上夹持板和下夹持板之间通过锁紧装置连接,所述上电极片和下电极片设置在上夹持板与下夹持板之间,所述上电极片固定在上夹持板上,所述下电极片固定在下夹持板上,所述上电极片和下电极片相对设置,所述上电极片和下电极片上分别连接有导线。本发明开发了特定夹具,通过夹具直接测试聚烯烃微孔膜自身内阻随温度变化规律,不用组装扣式电池,操作简单,并且减少了测量环境及测试工艺对测试结果的影响,大大提高了测试效率高,使测试结果更加稳定可靠。(The invention discloses a special fixture for testing the closed-cell membrane rupture temperature of a polyolefin microporous membrane, a testing device and a testing method. The special fixture comprises an upper clamping plate, a lower clamping plate, an upper electrode plate and a lower electrode plate, wherein the upper clamping plate and the lower clamping plate are arranged oppositely, the upper clamping plate and the lower clamping plate are connected through a locking device, the upper electrode plate and the lower electrode plate are arranged between the upper clamping plate and the lower clamping plate, the upper electrode plate is fixed on the upper clamping plate, the lower electrode plate is fixed on the lower clamping plate, the upper electrode plate and the lower electrode plate are arranged oppositely, and wires are connected to the upper electrode plate and the lower electrode plate respectively. The invention develops a specific clamp, directly tests the internal resistance change rule of the polyolefin microporous membrane per se along with the temperature through the clamp, does not need to assemble a button cell, has simple operation, reduces the influence of the measurement environment and the test process on the test result, greatly improves the test efficiency and ensures that the test result is more stable and reliable.)

1. The utility model provides a polyolefin microporous membrane obturator rupture of membranes temperature test special fixture which characterized in that: the special fixture comprises an upper clamping plate, a lower clamping plate, an upper electrode plate and a lower electrode plate, wherein the upper clamping plate and the lower clamping plate are arranged oppositely, the upper clamping plate and the lower clamping plate are connected through a locking device, the upper electrode plate and the lower electrode plate are arranged between the upper clamping plate and the lower clamping plate, the upper electrode plate is fixed on the upper clamping plate, the lower electrode plate is fixed on the lower clamping plate, the upper electrode plate and the lower electrode plate are arranged oppositely, and wires are connected to the upper electrode plate and the lower electrode plate respectively.

2. The special fixture according to claim 1, characterized in that: and the upper electrode plate and the lower electrode plate are respectively provided with a temperature probe.

3. The special fixture according to claim 1, characterized in that: the upper electrode plate is fixed on the upper clamping plate through an upper insulating block, and the lower electrode plate is fixed on the lower clamping plate through a lower insulating block.

4. The special fixture according to claim 1, characterized in that: the locking device comprises a hinge and a locking bolt, the hinge is connected with one end of the upper clamping plate and one end of the lower clamping plate, and the locking bolt is connected with the other end of the upper clamping plate and the other end of the lower clamping plate.

5. A polyolefin microporous membrane obturator rupture of membranes temperature test device which characterized in that: the testing device comprises a heating device, an internal resistance testing device, a data processing device and the special fixture as claimed in any one of claims 1 to 4, wherein the heating device is used for heating the special fixture, the internal resistance testing device is connected with the conducting wires of the upper electrode plate and the lower electrode plate, the internal resistance testing device is used for monitoring the internal resistance between the upper electrode plate and the lower electrode plate, and the data processing device is used for recording and processing temperature and internal resistance data.

6. A method for performing a closed cell rupture temperature test on a polyolefin microporous membrane by using the test device of claim 5, wherein the closed cell rupture temperature test comprises the following steps: the method comprises the following steps:

(1) clamping a polyolefin microporous membrane to be detected between an upper electrode plate and a lower electrode plate, dripping electrolyte, locking an upper clamping plate and a lower clamping plate, and then putting a special clamp into a heating device;

(2) heating by a heating device, monitoring internal resistance between an upper electrode plate and a lower electrode plate by an internal resistance testing device, and recording temperature and internal resistance data by a data processing device; the temperature when the internal resistance value is increased to the internal resistance value of the closed hole is the closed hole temperature, and the temperature when the internal resistance value is reduced to the rupture internal resistance value is the rupture temperature.

7. The method of claim 6, wherein: the internal resistance of the closed hole is not less than 100 omega, and the internal resistance of the rupture membrane is not more than 100 omega.

Technical Field

The invention belongs to the field of battery diaphragm materials, and particularly relates to a special fixture for testing the closed-cell film breaking temperature of a polyolefin microporous film, a testing device and a testing method.

Background

The safety problem of an electrochemical device using the microporous membrane is directly influenced by the closed pore temperature and the membrane breaking temperature of the polyolefin microporous membrane, so that the accurate measurement of the closed pore temperature and the membrane breaking temperature of the polyolefin microporous membrane becomes a subject of common concern in the diaphragm industry and downstream use enterprises.

The polyolefin microporous membrane mainly plays a role in isolating positive and negative pole pieces and providing an ion transmission channel in an electrochemical device. With the temperature of the electrochemical device being increased, the polyolefin microporous membrane is melted and flows to block pores, so that the ion transmission in the electrolyte is blocked, and the internal resistance is increased finally, which is called a closed pore process; as the temperature is further increased, the polyolefin material fails to provide a support structure, resulting in local rupture and thus local short circuit, which is a thermal anomaly of the electrochemical device, and this process is called a membrane rupture process.

In the prior art, the closed pore temperature of the porous film is often tested by baking the porous film at different temperatures and observing the microstructure of the processed porous film by using a scanning electron microscope. On the basis of the method, the air permeability value of the porous film is tested to test the pore closing temperature of the porous film, the method relatively improves the test speed, but the problems of large fluctuation and low consistency of the test result cannot be fundamentally solved, so the method has no popularization significance. The internal resistance of the porous film at different temperatures can be tested to test the closed pore temperature of the porous film, but the method has high control requirements on test equipment (such as temperature consistency and rapid volatilization of electrolyte at high temperature), and becomes a problem which is difficult to solve by researchers.

In the prior art, the resistance of the porous film is tested by using a button cell as in the invention patent (CN101625271A), which is a method for manufacturing a button cell and testing the resistance of the button cell. However, the preparation of the button cell is greatly influenced by human factors, such as the proficiency of a button cell maker directly influences the assembly effect of the button cell, and the button cell cannot form stable pressure on the porous film, and these factors all influence the testing efficiency and the testing result of the resistance of the porous film.

For the above-mentioned testing of porous membranes, a general test method and a stable test tool have not been developed yet.

Disclosure of Invention

In view of this, the invention aims to provide a special fixture for testing the closed-cell membrane rupture temperature of a polyolefin microporous membrane, a testing device and a testing method, which have high testing efficiency and stable and reliable testing results.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides a special fixture for testing the obturator and membrane rupture temperature of a polyolefin microporous membrane, which comprises an upper clamping plate, a lower clamping plate, an upper electrode plate and a lower electrode plate, wherein the upper clamping plate and the lower clamping plate are oppositely arranged, the upper clamping plate and the lower clamping plate are connected through a locking device, the upper electrode plate and the lower electrode plate are arranged between the upper clamping plate and the lower clamping plate, the upper electrode plate is fixed on the upper clamping plate, the lower electrode plate is fixed on the lower clamping plate, the upper electrode plate and the lower electrode plate are oppositely arranged, and wires are respectively connected onto the upper electrode plate and the lower electrode plate.

As a preferred technical solution, the upper electrode plate and the lower electrode plate are respectively provided with a temperature probe.

As a preferred technical scheme, the upper electrode plate is fixed on the upper clamping plate through an upper insulating block, and the lower electrode plate is fixed on the lower clamping plate through a lower insulating block.

According to the preferable technical scheme, the locking device comprises a hinge and a locking bolt, the hinge is connected with one end of the upper clamping plate and one end of the lower clamping plate, and the locking bolt is connected with the other end of the upper clamping plate and the other end of the lower clamping plate.

The invention also provides a device for testing the closed-cell membrane rupture temperature of the polyolefin microporous membrane, which comprises a heating device, an internal resistance testing device, a data processing device and the special clamp, wherein the heating device is used for heating the special clamp, the internal resistance testing device is connected with the conducting wires of the upper electrode plate and the lower electrode plate, the internal resistance testing device is used for monitoring the internal resistance between the upper electrode plate and the lower electrode plate, and the data processing device is used for recording and processing temperature and internal resistance data.

The invention also provides a method for testing the closed-cell membrane rupture temperature of the polyolefin microporous membrane, which comprises the following steps:

(1) clamping a polyolefin microporous membrane to be detected between an upper electrode plate and a lower electrode plate, dripping electrolyte, locking an upper clamping plate and a lower clamping plate, and then putting a special clamp into a heating device;

(2) heating by a heating device, monitoring internal resistance between an upper electrode plate and a lower electrode plate by an internal resistance testing device, and recording temperature and internal resistance data by a data processing device; the temperature when the internal resistance value is increased to the internal resistance value of the closed hole is the closed hole temperature, and the temperature when the internal resistance value is reduced to the rupture internal resistance value is the rupture temperature.

As a preferred technical scheme, the internal resistance of the closed hole is more than or equal to 100 omega, and the internal resistance of the rupture membrane is less than or equal to 100 omega.

The invention has the beneficial effects that:

the invention develops a specific clamp, directly tests the internal resistance change rule of the polyolefin microporous membrane per se along with the temperature through the clamp, does not need to assemble a button cell, has simple operation, reduces the influence of the measurement environment and the test process on the test result, greatly improves the test efficiency and ensures that the test result is more stable and reliable.

Drawings

In order to make the object, technical scheme and beneficial effect of the invention more clear, the invention provides the following drawings for explanation:

FIG. 1 is a schematic structural view (perspective view) of a special fixture;

FIG. 2 is a schematic structural view (front view) of the special fixture;

FIG. 3 is a schematic diagram of a testing apparatus.

Detailed Description

The present invention is further described with reference to the following drawings and specific examples so that those skilled in the art can better understand the present invention and can practice the present invention, but the examples are not intended to limit the present invention.

As shown in fig. 1 and 2, the special fixture for testing the closed-cell membrane rupture temperature of the polyolefin microporous membrane comprises an upper clamping plate 1, a lower clamping plate 2, an upper electrode plate 3 and a lower electrode plate 4; the upper clamping plate 1 and the lower clamping plate 2 are oppositely arranged, the upper clamping plate 1 and the lower clamping plate 2 are connected through a locking device, the locking device comprises a hinge 5 and a locking bolt 6, the hinge 5 is connected with one end of the upper clamping plate 1 and one end of the lower clamping plate 2, and the locking bolt 6 is connected with the other end of the upper clamping plate 1 and the other end of the lower clamping plate 2; the electrode plate 3 and the lower electrode plate 4 are arranged between the upper clamping plate 1 and the lower clamping plate 2, the upper electrode plate 3 is fixed on the upper clamping plate 1 through an upper insulating block 7, the lower electrode plate 4 is fixed on the lower clamping plate 2 through a lower insulating block 8, the upper electrode plate 3 and the lower electrode plate 4 are arranged oppositely, the upper electrode plate 3 and the lower electrode plate 4 are respectively connected with a lead 9, and the upper electrode plate 3 and the lower electrode plate 4 are respectively provided with a temperature probe 10.

As shown in fig. 3, the testing device for closed-cell membrane rupture temperature of the polyolefin microporous membrane comprises a heating device 11, an internal resistance testing device 12, a data processing device 13 and the special fixture, wherein the heating device 11 is used for heating the special fixture, the internal resistance testing device 12 is connected with the conducting wires 9 of the upper electrode plate 3 and the lower electrode plate 4, the internal resistance testing device 12 is used for monitoring the internal resistance between the upper electrode plate 3 and the lower electrode plate 4, and the data processing device 13 is used for recording and processing temperature and internal resistance data.

The method for carrying out the closed-cell membrane rupture temperature test on the polyolefin microporous membrane by using the test device comprises the following steps:

(1) clamping a polyolefin microporous membrane to be detected between an upper electrode plate 3 and a lower electrode plate 4, dripping electrolyte, locking an upper clamping plate 1 and a lower clamping plate 2, and then putting a special clamp into a heating device 11;

(2) the heating device 11 heats up, the internal resistance testing device 12 monitors the internal resistance between the upper electrode plate 3 and the lower electrode plate 4, and the data processing device 13 records the temperature and the internal resistance data; the temperature when the internal resistance value rises to reach 100 Ω for the first time is the closed-cell temperature, and the temperature when the internal resistance value decreases to reach 100 Ω for the second time is the film rupture temperature.

Four tests were performed on three types of polyolefin microporous membrane samples using the test apparatus and method described above, respectively, and the results are shown in table 1.

TABLE 1 polyolefin microporous membrane closed-cell rupture test data

As can be seen from Table 1, the minimum closed cell temperature of PE1 was 138.3 ℃ and the maximum rupture temperature was 155.6 ℃; the minimum closed pore temperature of PE2 is 139.1 ℃, and the maximum film breaking temperature is 159.0 ℃; the minimum closed cell temperature of PE3 was 137.1 ℃ and the maximum rupture temperature was 161.2 ℃. Therefore, the testing device and the testing method can accurately identify the processes of closing the pores and breaking the membranes of the polyolefin microporous membrane and distinguish the characteristics of closing the pores and breaking the membranes of different types of the polyolefin microporous membrane.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.