Cylindrical lithium ion battery air tightness test fixture

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a cylindrical lithium ion battery air tightness test fixture which comprises a supporting frame and a test jig fixed above the supporting frame, and a lithium ion fixing loading fixture is fixed in the test jig. A gas transmission pipe for communicating the gas transmission equipment with the loading fixture is arranged above the test fixture, a test module connected with the loading fixture is arranged below the test fixture, the test module is composed of a first sealing test mechanism and a second sealing test mechanism, and the first sealing test mechanism is connected with the loading fixture. The first sealing test mechanism and the second sealing test mechanism can realize visualization of air tightness detection of the lithium ion battery, and the first sealing test mechanism is communicated with the loading clamp; and a cleaning module for cleaning the first sealing test mechanism is arranged on the upper surface of the support frame. The system has the advantages of visualization, modularization, high efficiency, compactness, improvement of test efficiency and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-ion batteries, and particularly to an airtightness test fixture for a cylindrical lithium-ion battery. Background Art

[0002] A lithium-ion battery is a secondary battery that mainly works by the movement of lithium ions between the positive electrode and the negative electrode. During the charge and discharge process, Li+ intercalates and deintercalates between the two electrodes: during charging, Li+ deintercalates from the positive electrode and intercalates into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; during discharging, the opposite occurs. Lithium-ion batteries use non-aqueous liquid organic electrolytes. In real life, most lithium-ion batteries are cylindrical in shape, which is not only convenient for assembly but also occupies a relatively reasonable space; in order to protect the safety and stability of the internal components of the battery, an airtightness test is required to detect the sealing performance of key parts such as the welding points and sealing rings of the cylindrical lithium-ion battery, and prevent external air, moisture or dust from entering the battery interior.

[0003] Chinese Patent CN210442044U discloses "an airtightness test fixture for a cylindrical lithium-ion battery, including an exhaust pipe, a sealing gasket, a fastening sleeve, a fixing bolt, a sealing cover, a sealing flange and an observation chamber. The upper end surface of the sealing cylinder is fitted with a sealing cover, a sealing flange is installed on the upper side of the sealing cover, a fixing bolt is connected to the upper right side of the upper end surface of the sealing cover, the circumferential side surface of the cylindrical lithium-ion battery body is fitted with a fastening sleeve, the lower end surface of the cylindrical lithium-ion battery body is fitted with a sealing gasket, an exhaust pipe is installed on the right side of the circumferential side surface of the sealing cylinder, and an observation chamber is provided on the left side of the exhaust pipe".

[0004] The above patent also has the following defects: such as strong subjectivity, easy to cause inaccurate observation due to factors such as light and angle, and unable to analyze the test results each time, which is not convenient for providing data support for the battery production quality.

[0005] Therefore, it is urgent to improve the above test equipment to solve the existing problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an airtightness test fixture for a cylindrical lithium-ion battery, which brings many benefits such as automatic cleaning, linkage design, compact structure, reliable testing, strong adaptability, visualization and intuitiveness to the airtightness test fixture for lithium-ion batteries, and has the advantage of higher efficiency.

[0007] To achieve the above object, the main technical solutions adopted by the present invention include: a support frame and a test fixture fixed above the support frame. A loading fixture for fixing lithium ions is fixed inside the test fixture. An air delivery pipe connecting the air delivery device and the loading fixture is arranged above the test fixture. A test module connected to the loading fixture is arranged below the test fixture. Among them, the test module is composed of a first seal test mechanism and a second seal test mechanism. The first seal test mechanism and the second seal test mechanism can realize the visualization of the airtightness detection of the lithium-ion battery. The first seal test mechanism is communicated with the loading fixture;

[0008] A cleaning module for cleaning the first seal test mechanism is arranged on the upper surface of the support frame. The cleaning module includes a liquid storage tank, a cleaning structure and an infusion structure;

[0009] The cleaning structure includes a cleaning block and a telescopic shaft arranged inside the first seal test mechanism. The bottom end of the telescopic shaft extends outside the first seal test mechanism, and a transmission structure for driving the second seal test mechanism and the infusion structure is installed at the bottom end of the telescopic shaft.

[0010] Preferably, a sealing door is hinged and installed outside the test fixture. A carrier platform for supporting the loading fixture is fixed inside the test fixture. An airbag expansion sleeve for fixing the lithium-ion battery is fixed inside the loading fixture. A sealing cover is bolted to the top side of the test fixture. The air delivery pipe is detachably installed inside the sealing cover.

[0011] Preferably, the first seal test mechanism includes a display cylinder fixed to the lower surface of the test fixture, a mounting frame fixed to the top side of the display cylinder, and a chromogenic agent block detachably installed on the mounting frame. A communication pipe is fixedly connected between the display cylinder and the carrier platform.

[0012] Preferably, the communication pipe penetrates through the upper and lower ends, and ventilation holes are coaxially arranged on the top side of the display cylinder, inside the carrier platform and the bottom side of the loading fixture. The display cylinder is made of transparent material.

[0013] Preferably, the transmission structure includes a second transmission rod and a second rack slidably arranged on the upper surface of the support frame, a first transmission rod hinged between the telescopic shaft and the second transmission rod. The transmission structure further includes a connecting rod fixed to the outer surface of the second transmission rod and connected to the second seal test mechanism. A stirring rod extending outside the liquid storage tank is installed inside the liquid storage tank by bearing. A second transmission gear meshing with the second rack is fixed to one end of the stirring rod.

[0014] Preferably, the second sealing test mechanism includes a bottom case fixed to the upper surface of the support frame, a top case bolted to the top side of the bottom case, a sliding seat slidably disposed inside the bottom case, a transmission shaft rotatably mounted inside the bottom case, a pointer rotatably mounted inside the top case, and a transmission member mounted between the transmission shaft and the sliding seat. One end of the connecting rod away from the second transmission rod extends into the bottom case and is fixed to the outer surface of the sliding seat.

[0015] Preferably, the transmission member is composed of a first transmission gear and a first rack that mesh with each other. The first transmission gear is fixed to the outer surface of the bottom end of the transmission shaft, and the first rack is fixed to the side of the sliding seat away from the second transmission rod. The top end of the transmission shaft is fixed to the pointer, and scale lines for cooperating with the rotation of the pointer are provided inside the top case.

[0016] Preferably, a guide rod passing through the inside of the sliding seat is fixed between the inner walls on opposite sides of the bottom case. The cleaning structure further includes a scraping sleeve fixed to the outer surface of the cleaning block and abutting against the inner side of the display cylinder. A liquid storage cavity and a spray hole are formed inside the cleaning block. The inside of the telescopic shaft is hollow, and an infusion hole communicating with the liquid storage cavity is opened at its top side.

[0017] Preferably, the infusion structure includes a piston cylinder, check valves fixedly communicated with the upper and lower sides of the piston cylinder, and a piston block reciprocatingly disposed inside the piston cylinder. Valves are elastically hinged inside both of the two check valves. An abutting block is provided outside the piston cylinder, and an elastic rod is mounted between the piston block and the abutting block;

[0018] A third transmission rod that intermittently fits against the outside of the abutting block is fixed to the outer surface of the second transmission rod.

[0019] Preferably, a mounting seat for fixing the piston cylinder is bolted to the upper surface of the support frame. A first connecting pipe is fixed between the top check valve and the telescopic shaft, and a second connecting pipe is fixedly communicated between the bottom check valve and the liquid storage tank. A guiding chute for limiting the second rack is formed on the upper surface of the support frame.

[0020] The present invention has at least the following beneficial effects:

[0021] 1. For this cylindrical lithium-ion battery airtightness test fixture, the display cylinder is made transparent, so that the internal changes during the test can be visually observed. When there is air leakage in the lithium-ion battery, the gas will enter the display cylinder through the loading fixture, the carrier table, and the connecting pipe, and react with the color-developing agent block, resulting in a color change. This visual feedback enables the inspectors to quickly judge the airtightness state of the battery.

[0022] 2. The airtightness test fixture for cylindrical lithium-ion batteries has a conical bottom for the air delivery pipe. This design helps to better align with the interfaces of the loading fixture or the lithium-ion battery, reducing the possibility of gas leakage and improving the accuracy of the test. Moreover, the conical bottom of the air delivery pipe helps to reduce the resistance during gas transportation and improve the gas flow efficiency.

[0023] 3. The airtightness test fixture for cylindrical lithium-ion batteries can visually display certain key parameters during the test through the cooperation of a pointer and a scale line. The visual feedback enables the inspectors to quickly understand the test results without relying on complex instrument readings or data analysis.

[0024] 4. The airtightness test fixture for cylindrical lithium-ion batteries has a cleaning structure that can automatically clean the inside of the first sealing test mechanism, especially the inner side of the display cylinder. By the close contact between the scraping sleeve and the inner side of the display cylinder, residues can be effectively removed, keeping the test environment clean.

[0025] 5. The airtightness test fixture for cylindrical lithium-ion batteries realizes the linkage between the cleaning module and the second sealing test mechanism through the design of the transmission structure. The telescopic movement of the telescopic shaft drives the movement of the second transmission rod and the second rack, and then drives the second sealing test mechanism to perform the test operation, improving the test efficiency. At the same time, the intermittent fitting design of the third transmission rod and the abutting block makes the piston block reciprocate in the piston cylinder, providing power for the delivery of the cleaning liquid and realizing the synchronization of cleaning and testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0027] Figure 1 is a three-dimensional view of the overall structure of the present invention;

[0028] Figure 2 is a sectional view of the structure of the test fixture of the present invention;

[0029] Figure 3 is a schematic view of the structure of the loading fixture of the present invention;

[0030] Figure 4 is a schematic view of the structure of the transmission structure of the present invention;

[0031] Figure 5 is a schematic view of the structure of the first sealing test mechanism and the cleaning structure of the present invention;

[0032] Figure 6 is a schematic view of the structure of the second sealing test mechanism of the present invention;

[0033] Figure 7 It is a schematic structural diagram of the infusion structure of the present invention;

[0034] Figure 8 It is a structural sectional view of the liquid storage tank of the present invention.

[0035] In the figure, 1, support frame; 2, test fixture; 21, sealing door; 22, sealing cover; 23, gas transmission pipe; 24, carrier platform; 25, loading fixture; 26, airbag tightening sleeve; 3, first sealing test mechanism; 301, display cylinder; 302, ventilation hole; 303, mounting frame; 304, developer block; 305, connecting pipe; 4, second sealing test mechanism; 401, bottom shell; 402, top shell; 403, sliding seat; 404, transmission shaft; 405, pointer; 406, scale line; 407, first transmission gear; 408, first rack; 409, guide rod; 5, liquid storage tank; 51, stirring rod; 6, cleaning structure; 601, cleaning block; 602, telescopic shaft; 603, scraping sleeve; 604, liquid storage cavity; 605, spray hole; 606, infusion hole; 7, infusion structure; 701, piston cylinder; 702, check valve pipe; 703, piston block; 704, valve; 705, abutting block; 706, elastic rod; 707, first connecting pipe; 708, second connecting pipe; 709, mounting seat; 8, transmission structure; 801, first transmission rod; 802, second transmission rod; 803, connecting rod; 804, second rack; 805, second transmission gear; 806, third transmission rod; 9, guiding chute. Specific embodiments

[0036] The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments.

[0037] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, in which the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0038] As Figures 1 - 5As shown in the figure, a cylindrical lithium-ion battery airtightness test fixture includes a support frame 1 and a test fixture 2 fixed above the support frame 1. Inside the test fixture 2, a loading fixture 25 for fixing lithium ions is fixed. Above the test fixture 2, an air delivery pipe 23 connecting the air delivery device and the loading fixture 25 is provided. An airtight door 21 is hingedly installed outside the test fixture 2. Inside the test fixture 2, a carrier table 24 for supporting the loading fixture 25 is fixed. Inside the loading fixture 25, an airbag expansion sleeve 26 for fixing the lithium-ion battery is fixed. The design of the airbag expansion sleeve 26 inside the loading fixture 25 can be adjusted according to lithium-ion batteries of different sizes, so as to adapt to the testing of batteries of various specifications. A sealing cover 22 is installed on the top side of the test fixture 2 by bolts, and the air delivery pipe 23 is detachably installed inside the sealing cover 22. The bottom of the air delivery pipe 23 is conical. The bottom of the air delivery pipe 23 being conical helps to better align with the interface of the loading fixture 25 or the lithium-ion battery, reduce the possibility of gas leakage, and improve the accuracy of the test. It should be noted that the air delivery pipe 23 can be adjusted up and down inside the sealing cover 22. When the sealing cover 22 is fixed on the top side of the test fixture 2, it is convenient to hermetically dock the air delivery pipe 23 with the cylindrical lithium-ion battery.

[0039] As Figure 1 , Figure 2 , Figure 4 and Figure 5 shown in the figure, a test module connected to the loading fixture 25 is provided below the test fixture 2. Among them, the test module consists of a first airtightness test mechanism 3 and a second airtightness test mechanism 4. The first airtightness test mechanism 3 and the second airtightness test mechanism 4 can realize the visualization of the airtightness detection of the lithium-ion battery. The first airtightness test mechanism 3 is communicated with the loading fixture 25; As Figure 4 and Figure 5As shown, the first sealing test mechanism 3 includes a display tube 301 fixed to the lower surface of the test fixture 2, a mounting frame 303 fixed to the top side of the display tube 301, and a developer block 304 detachably mounted on the mounting frame 303, and a connecting pipe 305 is fixedly connected between the display tube 301 and the stage 24. Among them, the connecting pipe 305 is connected at both ends, and the top side of the display tube 301, the inside of the stage 24 and the bottom side of the loading fixture 25 are all provided with coaxially arranged vents 302, and the connecting pipe 305, the top side of the display tube 301, the inside of the stage 24 and the bottom side of the loading fixture 25 are all provided with coaxially arranged vents 302. This coaxial design ensures that the flow path of the gas during the test is straight and continuous, reduces the possibility of gas leakage, and thus improves the accuracy of the test. The display tube 301 is transparent. The display tube 301 is transparent, so that the changes inside the test process can be intuitively observed. When there is gas leakage in the lithium-ion battery, the gas will enter the display tube 301 through the loading fixture 25, the stage 24, and the connecting pipe 305, and react with the developer block 304, resulting in a color change. This visual feedback allows the inspector to quickly determine the airtightness status of the battery.

[0040] To further improve the detection visualization, such as Figure 1 , Figure 2 , Figure 4 and Figure 6 As shown, the second sealing test mechanism 4 includes a bottom shell 401 fixed to the upper surface of the support frame 1, a top shell 402 bolted to the top side of the bottom shell 401, a slide seat 403 slidably arranged inside the bottom shell 401, a transmission shaft 404 with a bearing installed inside the bottom shell 401, a pointer 405 rotatably installed inside the top shell 402, and a transmission member installed between the transmission shaft 404 and the slide seat 403, wherein the transmission member is composed of a first transmission gear 407 and a first rack 408 meshing with each other, the first transmission gear 407 is fixed to the outer surface of the bottom end of the transmission shaft 404, the first rack 408 is fixed to the side of the slide seat 403 away from the second transmission rod 802, the top end of the transmission shaft 404 is fixed to the pointer 405, and a scale line 406 is arranged inside the top shell 402 for rotating the pointer 405. Through the cooperation of the pointer 405 and the scale line 406, some key parameters (such as gas pressure changes, leakage degree, etc.) in the test process can be intuitively displayed. This visual feedback enables the tester to quickly understand the test results without relying on complex instrument readings or data analysis. To ensure stable driving, a guide rod 409 that runs through the interior of the slide 403 is fixed between the inner walls of the opposite side of the bottom shell 401. The guide rod 409 runs through the interior of the slide 403 and provides stable guidance and support for the sliding of the slide 403. This helps to reduce the shaking and deviation of the slide 403 during the sliding process, thereby improving the accuracy and reliability of the test.

[0041] It is worth mentioning that the rotation of the pointer 405 directly reflects the rotation of the transmission shaft 404, and the rotation of the transmission shaft 404 is associated with the sliding of the slide 403 (through the engagement of the first transmission gear 407 and the first rack 408). This mechanical transmission method reduces the dependence on electronic components and improves the intuitiveness and accuracy of the test. At the same time, the design of the second seal test mechanism 4 can be adjusted and optimized according to different test requirements. For example, by changing the specifications and parameters of the transmission parts (such as the first transmission gear 407 and the first rack 408), it can adapt to different test conditions, achieving the advantage of strong adaptability.

[0042] For better testing, as Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 7 and Figure 8 shown, a cleaning module for cleaning the first seal test mechanism 3 is provided on the upper surface of the support frame 1. The cleaning module includes a liquid storage tank 5, a cleaning structure 6, and an infusion structure 7; as Figure 4 and Figure 5 shown, the cleaning structure 6 includes a cleaning block 601 and a telescopic shaft 602 disposed inside the first seal test mechanism 3. The bottom end of the telescopic shaft 602 extends outside the first seal test mechanism 3. The cleaning structure 6 further includes a scraping sleeve 603 fixed to the outer surface of the cleaning block 601 and abutted against the inner side of the display cylinder 301. The cleaning structure 6 can automatically clean the inside of the first seal test mechanism 3, especially the inner side of the display cylinder 301. Through the close contact between the scraping sleeve 603 and the inner side of the display cylinder 301, residues are effectively removed, keeping the test environment clean. A liquid storage cavity 604 and spray holes 605 are provided inside the cleaning block 601. The telescopic shaft 602 is hollow inside, and an infusion hole 606 communicating with the liquid storage cavity 604 is provided on its top side. The display cylinder 301 is provided with a detachable inspection cover, which is convenient for cleaning the cleaning block 601 and the scraping sleeve 603.

[0043] As Figure 7As shown, the infusion structure 7 includes a piston cylinder 701, check valves 702 fixedly connected to the upper and lower sides of the piston cylinder 701, and a piston block 703 reciprocatingly arranged inside the piston cylinder 701. Elastic hinges 704 are installed inside both of the two check valves 702. An abutting block 705 is arranged outside the piston cylinder 701, and an elastic rod 706 is installed between the piston block 703 and the abutting block 705. Among them, a mounting seat 709 for fixing the piston cylinder 701 is bolted to the upper surface of the support frame 1. A first connecting pipe 707 is fixed between the top check valve 702 and the telescopic shaft 602, and a second connecting pipe 708 is fixedly connected and communicated between the bottom check valve 702 and the liquid storage tank 5. Through the cooperation of components such as the piston cylinder 701, the check valves 702, and the piston block 703, the infusion structure 7 realizes the automatic transportation of the cleaning liquid and reduces the complexity of manual operation.

[0044] To achieve the linkage of the structure, as Figure 1 , Figure 2 , Figure 4 and Figure 6 shown, a transmission structure 8 for driving the second sealing test mechanism 4 and the infusion structure 7 is installed at the bottom end of the telescopic shaft 602. The transmission structure 8 includes a second transmission rod 802 and a second rack 804 slidably arranged on the upper surface of the support frame 1, and a first transmission rod 801 hinged between the telescopic shaft 602 and the second transmission rod 802. The transmission structure 8 further includes a connecting rod 803 fixed to the outer surface of the second transmission rod 802 and connected to the second sealing test mechanism 4. A stirring rod 51 extending to the outside is installed inside the liquid storage tank 5 through a bearing, and a second transmission gear 805 meshing with the second rack 804 is fixed to one end of the stirring rod 51. The meshing design of the stirring rod 51 and the second transmission gear 805 enables the cleaning liquid to be evenly mixed in the liquid storage tank 5 and improves the cleaning effect. One end of the connecting rod 803 away from the second transmission rod 802 extends into the inner bottom shell 401 and is fixed to the outer surface of the sliding seat 403.

[0045] Among them, a third transmission rod 806 that intermittently fits with the outside of the abutting block 705 is fixed to the outer surface of the second transmission rod 802. The design of the transmission structure 8 realizes the linkage between the cleaning module and the second sealing test mechanism 4. Through the telescopic movement of the telescopic shaft 602, the movement of the second transmission rod 802 and the second rack 804 is driven, and then the second sealing test mechanism 4 is driven to perform the test operation, improving the test efficiency. At the same time, the intermittent fitting design of the third transmission rod 806 and the abutting block 705 enables the piston block 703 to reciprocate inside the piston cylinder 701, providing power for the transportation of the cleaning liquid and realizing the synchronous progress of cleaning and testing. A guiding chute 9 for limiting the second rack 804 is opened on the upper surface of the support frame 1.

[0046] It should be noted that the elastic rod 706 is composed of a rod and a spring. The spring is used according to requirements. For example, the infusion structure 7 can achieve manual infusion or be started in cooperation with the transmission structure 8 to achieve automatic infusion. A pressure relief valve is also provided on the display cylinder 301.

[0047] As Figures 1 - 8 shown, the principle of the cylindrical lithium-ion battery airtightness test fixture provided in this embodiment is as follows:

[0048] Place the lithium-ion battery into the airbag tightening sleeve 26 in the loading fixture 25, fix the battery through the airbag tightening sleeve 26, close the sealing door 21, install the sealing cover 22 with bolts to ensure the airtightness of the test environment, connect the gas transmission device with the loading fixture 25 through the gas transmission pipe 23, and fill the inside of the battery with gas for airtightness test. The gas enters the communication pipe 305 through the loading fixture 25 and then enters the display cylinder 301. If the battery leaks air, the gas will react with the color-developing agent block 304, and the color in the display cylinder 301 will change, thereby visually displaying the airtightness test result. On the contrary, if there is no air leakage, there will be no color change in the display cylinder 301;

[0049] When there is air leakage, at the same time, the cleaning block 601 in the display cylinder 301 will drive the telescopic shaft 602 to move downward. The downward movement of the telescopic shaft 602 drives the second sealing test mechanism 4 through the transmission structure 8. The second sealing test mechanism 4 provides accurate test results through the pointer 405 and the scale line 406, improving the accuracy of the test.

[0050] As used in the specification and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. The specification and claims do not use the difference in names as a way to distinguish components, but use the difference in functions of components as the criterion for distinction. As mentioned throughout the specification and claims, "comprising" is an open-ended term and should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range. Those skilled in the art can solve technical problems within a certain error range and basically achieve the technical effect.

[0051] It should be noted that the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a commodity or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent in such a commodity or system. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of another identical element in the commodity or system including the element.

[0052] The foregoing description has shown and described several preferred embodiments of the present invention. However, as previously mentioned, it should be understood that the present invention is not limited to the forms disclosed herein, should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications, and environments, and can be changed within the scope of the inventive concept described herein through the above teachings or the skills or knowledge in related fields. Any changes and variations made by those skilled in the art without departing from the spirit and scope of the present invention shall fall within the protection scope of the appended claims of the present invention.

Claims

1. A cylindrical lithium-ion battery air tightness test fixture, comprising a support frame (1) and a test fixture (2) fixed above the support frame (1), characterized in that: A loading fixture (25) for fixing lithium ions is fixed inside the test fixture (2); a gas delivery pipe (23) for connecting a gas delivery device with the loading fixture (25) is arranged above the test fixture (2); a test module connected to the loading fixture (25) is arranged below the test fixture (2); wherein the test module is composed of a first sealing test mechanism (3) and a second sealing test mechanism (4); the first sealing test mechanism (3) and the second sealing test mechanism (4) can realize visualization of the air tightness test of the lithium ion battery; and the first sealing test mechanism (3) is connected to the loading fixture (25); The upper surface of the support frame (1) is provided with a cleaning module for cleaning by a first sealing test mechanism (3), and the cleaning module comprises a liquid storage tank (5), a cleaning structure (6) and a liquid infusion structure (7); The cleaning structure (6) comprises a cleaning block (601) and a telescopic shaft (602) arranged inside the first sealing test mechanism (3); the bottom end of the telescopic shaft (602) extends to the outside of the first sealing test mechanism (3); and a transmission structure (8) for driving the second sealing test mechanism (4) and the infusion structure (7) is installed at the bottom end of the telescopic shaft (602).

2. The cylindrical lithium-ion battery airtightness test fixture according to claim 1, characterized in that: The test fixture (2) is hingedly mounted with a sealing door (21) on the outside, the test fixture (2) is fixed with a loading platform (24) supporting a loading fixture (25) on the inside, the loading fixture (25) is fixed with an airbag expansion sleeve (26) for fixing a lithium-ion battery, the top side bolts of the test fixture (2) are bolted with a sealing cover (22), and the air delivery pipe (23) is detachably mounted inside the sealing cover (22).

3. The cylindrical lithium-ion battery airtightness test fixture according to claim 2, characterized in that: The first sealing test mechanism (3) comprises a display tube (301) fixed to the lower surface of the test fixture (2), a mounting frame (303) fixed to the top side of the display tube (301), and a developer block (304) detachably mounted on the mounting frame (303), and a connecting pipe (305) is fixedly connected between the display tube (301) and the stage (24).

4. The cylindrical lithium-ion battery airtightness test fixture according to claim 3, characterized in that: The connecting tube (305) is connected at both ends, and coaxially arranged vent holes (302) are provided on the top side of the display tube (301), the inside of the stage (24) and the bottom side of the loading fixture (25). The display tube (301) is transparent.

5. The cylindrical lithium-ion battery airtightness test fixture according to claim 1, characterized in that: The transmission structure (8) comprises a second transmission rod (802) and a second rack (804) slidably arranged on the upper surface of the support frame (1), and a first transmission rod (801) hingedly installed between the telescopic shaft (602) and the second transmission rod (802). The transmission structure (8) further comprises a connecting rod (803) fixed to the outer surface of the second transmission rod (802) and connected to the second sealing test mechanism (4). The internal bearing of the liquid storage tank (5) is equipped with a stirring rod (51) extending outward thereof, and one end of the stirring rod (51) is fixed with a second transmission gear (805) meshing with the second rack (804).

6. The cylindrical lithium-ion battery airtightness test fixture according to claim 5, characterized in that: The second sealing test mechanism (4) comprises a bottom shell (401) fixed to the upper surface of the support frame (1), a top shell (402) bolted to the top side of the bottom shell (401), a slide seat (403) slidably arranged inside the bottom shell (401), a transmission shaft (404) with a bearing installed inside the bottom shell (401), a pointer (405) rotatably installed inside the top shell (402), and a transmission member installed between the transmission shaft (404) and the slide seat (403), and the end of the connecting rod (803) away from the second transmission rod (802) extends to the inside of the bottom shell (401) and is fixed to the outer surface of the slide seat (403).

7. The cylindrical lithium-ion battery airtightness test fixture according to claim 6, characterized in that: The transmission member is composed of a first transmission gear (407) and a first rack (408) that are meshed with each other. The first transmission gear (407) is fixed to the outer surface of the bottom end of the transmission shaft (404), and the first rack (408) is fixed to the side of the slide seat (403) away from the second transmission rod (802). The top end of the transmission shaft (404) is fixed to the pointer (405), and a scale line (406) for cooperating with the rotation of the pointer (405) is arranged inside the top shell (402).

8. The cylindrical lithium-ion battery airtightness test fixture according to claim 7, characterized in that: A guide rod (409) penetrating the interior of the slide seat (403) is fixed between the inner walls of the opposite side of the bottom shell (401). The cleaning structure (6) further comprises a scraper sleeve (603) fixed to the outer surface of the cleaning block (601) and abutting against the inner side of the display tube (301). A liquid storage chamber (604) and a spray hole (605) are provided inside the cleaning block (601). The interior of the telescopic shaft (602) is hollow, and a liquid infusion hole (606) communicating with the liquid storage chamber (604) is provided on the top side thereof.

9. The cylindrical lithium-ion battery airtightness test fixture according to claim 8, characterized in that: The infusion structure (7) comprises a piston cylinder (701), a check tube (702) fixedly connected to the upper and lower sides of the piston cylinder (701), and a piston block (703) reciprocatingly arranged inside the piston cylinder (701), the insides of the two check tubes (702) are elastically hinged with valves (704), the outside of the piston cylinder (701) is provided with an abutment block (705), and an elastic rod (706) is installed between the piston block (703) and the abutment block (705); A third transmission rod (806) is fixed to the outer surface of the second transmission rod (802) and is intermittently in contact with the outside of the abutment block (705).

10. The cylindrical lithium-ion battery airtightness test fixture according to claim 9, characterized in that: The upper surface of the support frame (1) is bolted with a mounting seat (709) for fixing the piston cylinder (701); a first connecting pipe (707) is fixed between the check tube (702) and the telescopic shaft (602) at the top; a second connecting pipe (708) is fixedly connected between the check tube (702) and the liquid storage tank (5) at the bottom; and a guide groove (9) for limiting the second rack (804) is provided on the upper surface of the support frame (1).

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