Airtight test tool for battery case
By using a flexible fixing and multi-seal structure for airtightness testing, the problems of unstable fixing and incomplete leakage detection in battery casing testing are solved, achieving efficient and accurate airtightness testing, which is suitable for the industrial production of battery casings.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-13
- Publication Date
- 2026-04-10
AI Technical Summary
Existing battery casing airtightness testing equipment is prone to scratches or deformation during fixing, and the test results are inaccurate, failing to fully identify potential air leaks and posing safety hazards.
The air-conducting connector, made of flexible and deformable material, is combined with a magnetohydrodynamic cavity and micro-particle airbags, along with a graphite plate air cushion and a multi-seal structure, to achieve flexible fixation and reliable sealing. Combined with internal and external inflation testing methods, it ensures the stability and accuracy of the test.
It improves the stability and accuracy of battery casing airtightness testing, reduces the intensity of manual operation, realizes full-process automation, and is suitable for large-scale industrial production.
Smart Images
Figure CN121829926A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery casing airtightness testing technology, and more particularly to an airtightness testing fixture for battery casings. Background Technology
[0002] As a crucial protective component of the battery, the airtightness of the battery casing directly affects the battery's safety and lifespan. If the battery casing leaks, external moisture, dust, and other impurities can easily enter the battery, causing short circuits and corrosion of internal components, potentially leading to battery bulging, fire, or even explosion. Simultaneously, leakage of the electrolyte inside the battery can affect its electrochemical performance, reducing its range and cycle life. Therefore, rigorous airtightness testing of the battery casing is a critical step in the battery manufacturing process.
[0003] Currently, existing battery casing airtightness testing equipment often uses rigid clamping to fix the battery casing during testing. This can easily lead to scratches and deformation on the surface of the battery casing, affecting not only its appearance but also its structural integrity, thus impacting the accuracy of the test results. If the fixing force is insufficient, the battery casing is prone to displacement during testing, which can also cause test errors. Secondly, the sealing reliability during testing is poor, and air leakage is likely to occur at the interface between the air inlet and the battery casing, causing distorted test data and making it impossible to accurately determine the actual airtightness of the battery casing. Moreover, most equipment can only test from a single direction (such as internal inflation testing for external leakage), failing to comprehensively investigate potential air leakage hazards in the battery casing. This allows some battery casings with hidden air leakage problems to enter the market, creating safety risks. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of existing technologies in the poor airtightness testing of battery casings, and to propose an airtightness testing fixture for battery casings.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: a gas tightness testing fixture for a battery casing, comprising a machine tool, wherein the machine tool is provided with a placement component, a first testing mechanism, and a second testing mechanism, and the placement component is located between the first testing mechanism and the second testing mechanism; the first testing mechanism includes a first inflation device mounted on the top of the machine tool via a movable component; the inflation end of the first inflation device is provided with an air guide block, and the air guide block is made of a flexible deformable material; a circular microparticle airbag is fixedly installed inside the air guide block and a circular magnetofluid cavity is formed therein, and the magnetofluid cavity is located in the inner circle of the microparticle airbag; a sealing groove is formed on the side of the air guide block near the rotating platform; a transfer mechanism is provided above the second testing mechanism; and a fixing mechanism for fixing the battery casing is provided between the first testing mechanism and the rotating mechanism.
[0006] Preferably, the placement assembly includes a rotating platform rotatably mounted on the top of the machine tool, the rotating platform being used to place the battery casing to be tested.
[0007] Preferably, a rotary motor is fixedly installed at the bottom of the machine tool, and the output end of the rotary motor is connected to the rotary platform through a transmission device.
[0008] Preferably, the moving component includes a first moving device fixedly mounted on the top of the machine tool, and the first inflation device is fixedly mounted on the moving end of the first moving device.
[0009] Preferably, the second testing mechanism includes a sealed cavity, a second moving device, and a second inflation device. The sealed cavity is disposed on the top of the machine tool, the second moving device is fixedly installed on the machine tool and located below the sealed cavity, and the second inflation device is fixed to the moving end of the second moving device.
[0010] Preferably, a protective cover is fixedly installed on the top of the machine tool, and the sealed cavity is located inside the protective cover.
[0011] Preferably, a conveyor is provided on the side of the protective cover away from the rotating platform for conveying the battery casing that has completed the test.
[0012] Preferably, the transfer mechanism includes a propulsion device, a lifting device, and a pneumatic adsorption device. The propulsion device is fixedly installed on the top of the machine tool, the lifting device is fixed to the moving end of the propulsion device, and the pneumatic adsorption device is fixed to the output end of the lifting device.
[0013] Preferably, a fixed frame is fixedly installed on the top of the machine tool, and the fixing mechanism includes a pressing machine fixedly installed on the top of the fixed frame. A pressing plate is fixedly installed on the output end of the pressing machine, and a graphite plate is fixedly installed on the bottom of the pressing plate. A sealing ring is provided around the graphite plate at the installation point of the pressing plate.
[0014] Preferably, the pressing plate has two symmetrically distributed air vents on both sides of the graphite plate, and each air vent has an arc groove around its periphery. An air pump is fixedly installed at the bottom of the machine tool, and the output end of the air pump is fixedly connected to an air inlet pipe, which is a flexible hose. The end of the air inlet pipe away from the air pump is fixedly connected to a distribution pipe, and the three air outlets of the distribution pipe are respectively connected to the pressing plate and the two air vents.
[0015] Compared with the prior art, the advantages of the present invention are as follows: This invention has three main features: First, it uses air vents through the gaps in the graphite plate to form an air cushion, achieving flexible fixation. This applies stable pressure to the battery casing to prevent displacement while avoiding deformation or surface damage caused by hard contact, and it does not interfere with subsequent pressure testing. Second, it utilizes the negative pressure effect created by the lateral air vents to further adsorb the sidewalls of the battery casing, enhancing the fixation effect and preventing casing displacement caused by equipment vibration or air pressure fluctuations during testing. Third, it employs a dual action of microparticle airbag compression combined with magnetic field solidification of the magnetic fluid, ensuring that the magnetic fluid tightly adheres to the battery casing interface. This strengthens the fixation stability at the interface and forms a reliable sealing barrier. This triple fixation mechanism, layer by layer, significantly improves the stability of the testing process.
[0016] This invention addresses two main issues. First, it incorporates a sealing ring at the mounting point of the graphite plate and the pressing plate to prevent gas leakage from the air cushion, ensuring stable air cushion pressure and preventing gas leakage from interfering with the pressure holding test inside the battery casing. Second, it uses magnetic fluid to solidify and seal the interface between the battery casing and the gas guide block, fundamentally solving the problem of gas leakage at the interface and eliminating pressure misjudgments caused by poor interface sealing. The multiple sealing structures work together to completely isolate external factors from interfering with the test, ensuring that the pressure monitoring data accurately reflects the airtightness of the battery casing.
[0017] This invention employs a two-way testing method: internal inflation testing for external leakage and external inflation testing for internal leakage. This method comprehensively investigates potential leakage hazards in the battery casing. Compared to traditional single testing methods, it offers more comprehensive testing coverage and significantly improves accuracy. Furthermore, a rotating mechanism enables the continuous transfer of multiple battery casings to be tested. Combined with automated transfer and conveying mechanisms, it achieves fully automated operation from loading, testing, transfer, and unloading, eliminating the need for manual intervention. This not only reduces labor intensity but also significantly improves testing efficiency, meeting the testing needs of large-scale industrial production. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall structure of an airtightness testing fixture for a battery casing proposed in this invention. Figure 2 This is a schematic diagram of the machine tool and air pump structure of an airtightness testing fixture for a battery casing proposed in this invention; Figure 3 This is a schematic diagram of the rotating motor and transmission device of an airtightness testing fixture for a battery casing proposed in this invention. Figure 4 This is a schematic diagram of the first inflation device and the first moving device of an airtightness testing fixture for a battery casing proposed in this invention. Figure 5 This is a schematic diagram of the second inflation device and the second moving device of an airtightness testing fixture for a battery casing proposed in this invention. Figure 6 This is a schematic diagram of the propulsion device and lifting device of an airtightness testing fixture for a battery casing proposed in this invention. Figure 7 This is a schematic diagram of the pressing plate and sealing ring structure of an airtightness testing fixture for a battery casing proposed in this invention.
[0019] In the diagram: 1 Machine tool, 2 Air pump, 3 Protective cover, 4 Rotary motor, 5 Transmission device, 6 Rotating platform, 7 First inflation device, 8 First moving device, 9 Fixed frame, 10 Pressing machine, 11 Pressing plate, 12 Air inlet pipe, 13 Air distribution pipe, 14 Sealing ring, 15 Graphite plate, 16 Arc groove, 17 Air outlet, 18 Air guide block, 19 Sealing groove, 20 Microparticle airbag, 21 Magnetofluid cavity, 22 Second moving device, 23 Second inflation device, 24 Propulsion device, 25 Lifting device, 26 Pneumatic adsorption device, 27 Sealing cavity, 28 Conveying table. Detailed Implementation
[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0021] Reference Figures 1 to 7A gas tightness testing fixture for battery casings includes a machine tool 1. The machine tool 1 is equipped with a rotating mechanism, a first testing mechanism, and a second testing mechanism, with the rotating mechanism located between the first and second testing mechanisms. The rotating mechanism includes a rotating platform 6 rotatably mounted on the top of the machine tool 1. A rotating motor 4 is fixedly mounted on the bottom of the machine tool 1. The output end of the rotating motor 4 is connected to the rotating platform 6 via a transmission device 5. The rotating motor 4 drives the rotating platform 6 to rotate via the transmission device 5. The rotating platform 6 is used to place the battery casings to be tested, enabling continuous transfer of multiple battery casings to be tested to improve testing efficiency. The first testing mechanism includes a first inflation device 7, which is mounted on the top of the machine tool 1 via a first moving device 8. The first inflation device 7 is fixedly mounted on the moving end of the first moving device 8. An air guide block 18 is provided at one end of the first inflation device 7 near the rotating platform 6. The air guide block 18 is made of a flexible, deformable material. A circular microparticle airbag 20 is fixedly installed inside the air guide block 18, and a circular magnetohydrodynamic cavity 21 is formed therein. 0. The magnetofluidic cavity 21 and the air guide block 18 are concentrically arranged. The magnetofluidic cavity 21 is located in the inner ring of the microparticle airbag 20. The air guide block 18 has a sealing groove 19 on the side near the rotating platform 6. The first moving device 8 drives the first inflation device 7 to move, so that the air guide block 18 at the front end of the first inflation device 7 is aligned with the interface on the battery casing, and the interface on the battery casing is inserted into the sealing groove 19 of the air guide block 18, achieving a preliminary seal. The microparticle airbag 20 is then evacuated, and the microparticles inside the airbag are tightly adhered to the inner wall under compression. The magnetic fluid cavity 21 is compressed, and at the same time, an electric current is applied to the magnetic fluid cavity 21 to generate a magnetic field. The magnetic fluid in the magnetic fluid cavity 21 is first compressed by the microparticles and tightly adheres to the interface of the battery shell. Then, under the influence of the magnetic field, it changes from a fluid to a solid and is more firmly adsorbed at the interface of the battery shell. The dual effect of the compression of the microparticle airbag 20 and the solidification of the magnetic fluid magnetic field makes the magnetic fluid tightly adhere to the interface of the battery shell, which not only strengthens the fixation stability at the interface, but also forms a reliable sealing barrier to avoid air leakage at the air guide block 18, which helps to improve the accuracy of the test.
[0022] A mounting bracket 9 is fixedly installed on the top of the machine tool 1. A pressing machine 10 is fixedly installed on the top of the mounting bracket 9. A pressing plate 11 is fixedly installed at the output end of the pressing machine 10. A graphite plate 15 is fixedly installed at the bottom of the pressing plate 11. Sealing rings 14 are provided around the graphite plate 15 where it is installed with the pressing plate 11 to prevent high-pressure gas leakage. Two air outlets 17 are provided on the pressing plate 11, and the two air outlets 17 are symmetrically distributed on both sides of the graphite plate 15. A circular arc groove 16 is provided around the periphery of each air outlet 17. An air pump 2 is fixedly installed at the bottom of the machine tool 1. An air inlet pipe 12 is fixedly connected to the output end of the air pump 2. The air inlet pipe 12 is a flexible hose. The end of the air inlet pipe 12 away from the air pump 2 is fixedly connected to a distribution pipe 13. The three air outlets of the distribution pipe 13 are respectively connected to the pressing plate 11 and the two air outlets 17. When the pressing machine 10 and the air pump 2 are started, the air pump 2 pushes high-pressure gas into the distribution pipe 13 through the air inlet pipe 12. The gas distribution pipe 13 introduces high-pressure gas into the central graphite plate 15 and the two side vents 17. At the same time, the presser 10 controls the pressing plate 11 to descend. The high-pressure gas passes through the gaps in the graphite plate 15, forming an air cushion between the pressing plate 11 and the battery casing. This achieves initial fixation of the battery casing and avoids damage to the battery casing or affecting the test results due to hard contact. The gas ejected from the vents 17 is guided by the arc groove 16 and ejected from the gap between the battery casing and the side wall of the pressing plate 11, increasing the gas flow rate and decreasing the pressure at the gap. This creates an adsorption effect on the battery casing, further enhancing the fixation effect and preventing movement during testing. For the internal leakage test, the first inflation device 7 inflates and maintains the pressure inside the battery casing. The pressure sensor inside the first inflation device 7 simultaneously tests the pressure change inside the battery casing. If the pressure stabilizes and does not change, it indicates that there is no internal leakage problem in the battery casing.
[0023] The second testing mechanism includes a sealed cavity 27, a second moving device 22, and a second inflation device 23. The sealed cavity 27 is located on the top of the machine tool 1 and has a sealed door inside. The second moving device 22 is fixedly installed on the machine tool 1 and located below the sealed cavity 27. The second inflation device 23 is fixedly installed at the moving end of the second moving device 22. The transfer mechanism is located above the second testing mechanism and includes a lifting device 25, a pushing device 24, and a pneumatic adsorption device 26. The pushing device 24 is fixedly installed on the top of the machine tool 1, the lifting device 25 is fixedly installed at the moving end of the pushing device 24, and the pneumatic adsorption device 26 is fixedly installed at the output end of the lifting device 25. A protective cover 3 is fixedly installed on the top of the machine tool 1, and the sealed cavity 27 is located inside the protective cover 3. The rotating motor 4 is started, and the rotating platform 6 is rotated through the transmission device 5 to move the battery casing that has completed the first step of testing to the front of the lifting device 25. The lifting device 25 and the pushing device 24 are started to adjust the position of the pneumatic adsorption device 26, and then the pneumatic adsorption device 26 adsorbs the battery casing and places it below. Inside the sealed cavity 27, the sealed door automatically closes. The second moving device 22 is activated to adjust the inflation end of the second inflation device 23 to align with the inflation port of the sealed cavity 27. Then, the second inflation device 23 inflates and pressurizes the inside of the sealed cavity 27. The pressure sensor inside the second inflation device 23 simultaneously tests the pressure change inside the battery casing, enabling external testing to determine if there is any leakage into the battery casing. This combination of internal and external testing covers both internal and external leakage scenarios. Compared to traditional single-direction testing, the test results are more comprehensive and accurate, helping to eliminate missed detections due to missing test dimensions. A conveyor 28 is set on the side of the protective cover 3 away from the rotating platform 6. After the secondary inspection, the sealed cavity 27 is opened, and the pneumatic adsorption device 26 is activated to remove the tested casing and place it on the conveyor 28 for transport. This completes the fully automated connection of loading, internal testing, transfer, external testing, and unloading, reducing manual operation and human error rate, while shortening the time spent switching between workstations. It is suitable for continuous testing of large batches of battery casings.
[0024] In operation, the battery casing is placed on the rotating platform 6, the first moving device 8 is activated, the air guide block 18 at the front end of the first inflation device 7 is aligned with the interface on the battery casing, and the interface on the battery casing is inserted into the sealing groove 19. The pressing machine 10 and the air pump 2 are activated. The air pump 2 injects high-pressure gas into the air distribution pipe 13 through the air inlet pipe 12. The air distribution pipe 13 then guides the high-pressure gas into the graphite plate 15 in the middle and the air outlets 17 on both sides. At the same time, the pressing machine 10 controls the pressing plate 11 to descend. Since the graphite plate 15 is located below the pressing plate 11, and sealing rings 14 are provided around the graphite plate 15 and at the mounting point of the pressing plate 11 to prevent air leakage, the high-pressure gas passes through the gaps in the graphite plate 15, forming an air cushion between the pressing plate 11 and the battery casing. This not only fixes the battery casing below but also prevents direct hard contact that could damage it. A damaged battery casing can affect measurement results. The vent 17 is a horizontal vent, which sprays out from the gap between the battery casing and the side wall of the pressing plate 11 along the arc groove 16. This results in a high gas flow rate and low pressure at the gap, which has a certain adsorption effect on the battery casing, further enhancing the fixation effect and preventing movement during testing. After fixation, the microparticle airbag 20 is evacuated. The microparticles in the airbag are compressed and tightly adhere to the inner wall, squeezing the magnetofluid cavity 21 below. At the same time, the magnetofluid cavity 21 is energized to generate a magnetic field. At this time, the magnetofluid in the magnetofluid cavity 21 is first squeezed by the microparticles and tightly adheres to the interface of the battery casing. Under the influence of the magnetic field, it changes from a fluid to a solid, thus adsorbing more firmly at the interface of the battery casing. This triple protection prevents air leakage at the air guide block 18 and improves the accuracy of the test.
[0025] After preparation, the battery casing is inflated and pressurized using the first inflation device 7, while simultaneously testing the pressure change inside the casing. If the pressure remains stable after stabilization, it indicates that the battery casing is leak-free. After the first battery casing is tested, the rotating motor 4 is started, which drives the rotating platform 6 to rotate via the transmission device 5, moving the next battery casing to be tested to the testing area. Simultaneously, the battery casing tested in the first step is moved to the front of the lifting device 25. The lifting device 25 and the propulsion device 24 are started, and the position of the pneumatic suction device 26 is adjusted to suction the battery casing and place it into the test area. The device moves into the lower sealed cavity 27 and closes it. The second moving device 22 is activated to move the second inflation device 23 to the side of the sealed cavity 27 to inflate and pressurize the inside of the sealed cavity 27. At the same time, the pressure change inside the battery casing is tested. This not only tests whether the battery casing leaks out from the inside, but also tests whether the battery casing leaks into the inside from the outside. Two testing methods are performed on a single battery casing to improve the accuracy of the test. Finally, the sealed cavity 27 is opened, the pneumatic adsorption device 26 is activated, the tested casing is taken out, and it is placed on the rear conveyor 28 for transport.
[0026] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A gas tightness testing fixture for a battery casing, comprising a machine tool (1), characterized in that, The machine tool (1) is provided with a placement component, a first testing mechanism and a second testing mechanism, and the placement component is located between the first testing mechanism and the second testing mechanism. The first testing mechanism includes a first inflation device (7) installed on the top of the machine tool (1) by a moving component. The inflation end of the first inflation device (7) is provided with an air guide block (18), and the air guide block (18) is made of a flexible deformable material. A circular micro-particle airbag (20) is fixedly installed inside the air guide block (18) and a circular magnetofluid cavity (21) is opened. The magnetofluid cavity (21) is located in the inner ring of the micro-particle airbag (20). A sealing groove (19) is opened on the side of the air guide block (18) near the rotating platform (6). A transfer mechanism is provided above the second testing mechanism. A fixing mechanism for fixing the battery casing is provided between the first testing mechanism and the rotating mechanism.
2. The airtightness testing fixture for a battery casing according to claim 1, characterized in that, The placement assembly includes a rotating platform (6) rotatably mounted on top of the machine tool (1), the rotating platform (6) being used to place the battery casing to be tested.
3. The airtightness testing fixture for a battery casing according to claim 2, characterized in that, The machine tool (1) is fixedly installed with a rotating motor (4) at the bottom. The output end of the rotating motor (4) is connected to the rotating platform (6) through a transmission device (5).
4. The airtightness testing fixture for a battery casing according to claim 1, characterized in that, The moving component includes a first moving device (8) fixedly installed on the top of the machine tool (1), and the first inflation device (7) fixedly installed on the moving end of the first moving device (8).
5. The airtightness testing fixture for a battery casing according to claim 1, characterized in that, The second testing mechanism includes a sealed cavity (27), a second moving device (22), and a second inflation device (23). The sealed cavity (27) is located on the top of the machine tool (1). The second moving device (22) is fixedly installed on the machine tool (1) and located below the sealed cavity (27). The second inflation device (23) is fixed to the moving end of the second moving device (22).
6. The airtightness testing fixture for a battery casing according to claim 5, characterized in that, The machine tool (1) is fixedly equipped with a protective cover (3) on its top, and the sealed cavity (27) is located inside the protective cover (3).
7. The airtightness testing fixture for a battery casing according to claim 6, characterized in that, The protective cover (3) has a conveyor (28) on the side away from the rotating platform (6) for conveying the battery casing that has completed the test.
8. The airtightness testing fixture for a battery casing according to claim 1, characterized in that, The transfer mechanism includes a propulsion device (24), a lifting device (25), and a pneumatic adsorption device (26). The propulsion device (24) is fixedly installed on the top of the machine tool (1), the lifting device (25) is fixed to the moving end of the propulsion device (24), and the pneumatic adsorption device (26) is fixed to the output end of the lifting device (25).
9. The airtightness testing fixture for a battery casing according to claim 1, characterized in that, The machine tool (1) is fixedly mounted on the top of a fixed frame (9). The fixed mechanism includes a press (10) fixedly mounted on the top of the fixed frame (9). A press plate (11) is fixedly mounted on the output end of the press (10). A graphite plate (15) is fixedly mounted on the bottom of the press plate (11). A sealing ring (14) is provided around the graphite plate (15) at the mounting point of the press plate (11).
10. A gas tightness testing fixture for a battery casing according to claim 9, characterized in that, The pressing plate (11) has two symmetrically distributed air outlets (17) on both sides of the graphite plate (15). Each air outlet (17) has an arc groove (16) around its periphery. An air pump (2) is fixedly installed at the bottom of the machine tool (1). The output end of the air pump (2) is fixedly connected to an air inlet pipe (12), which is a flexible hose. The end of the air inlet pipe (12) away from the air pump (2) is fixedly connected to a distribution pipe (13). The three air outlets of the distribution pipe (13) are respectively connected to the pressing plate (11) and the two air outlets (17).