Lithium battery packaging tightness detection device and detection method thereof

Abstract

The application discloses a lithium battery packaging airtightness detection equipment and a detection method thereof, relates to the technical field of lithium battery packaging airtightness detection, and comprises an operation table, a battery shell and a gas inlet device for inputting detection gas, further comprises a fixed cylinder for receiving the gas inlet device, a piston plate slidingly arranged in the fixed cylinder and driven by gas pressure, an adjusting unit drivingly connected with the piston plate and used for simulating a damaged state of the battery shell sealing, and a limiting unit drivingly connected with the piston plate and used for cooperating with the adjusting unit to change the sealing state of the battery shell. The application simulates the damaged state of the sealing gasket through the interaction of the upper magnet and the lower magnet, realizes the effect of detecting the sealing performance of the lithium battery shell after being used for a period of time, and observes whether the dye leaks through the cooperation of the transparent mark frame arranged on the battery shell and the fluorescent dye, so that the airtightness of the battery shell is detected.

Description

Technical Field

[0001] This invention relates to the field of lithium battery packaging airtightness testing technology, specifically to a lithium battery packaging airtightness testing device and its testing method. Background Technology

[0002] A lithium battery is a type of battery that uses lithium metal or lithium alloy as the positive and negative electrode materials and a non-aqueous electrolyte solution. A lithium battery mainly consists of two parts: the battery cell and the casing. Cell packaging requires placing the battery cell inside the lithium battery casing, which is then sealed with a sealing cap, completely isolating the inside of the casing from the outside and creating a sealed environment for the battery cell to ensure its electrochemical performance. Both the battery casing and the sealing cap use gaskets when connected to ensure that the electrolyte does not leak out and maintain normal battery operation. Existing lithium battery sealing performance testing methods mostly test the sealing performance of the casing without the sealing gasket installed, failing to fully consider the potential impact of gasket wear on the sealing performance of the lithium battery during actual use.

[0003] Traditional lithium battery packaging sealing testing equipment typically employs a helium detection method. During testing, the battery casing is treated as a closed cavity with a liquid injection port. The primary purpose of the test is to confirm whether there are any leaks in the battery casing other than the injection port. Existing helium detection equipment places the battery under test in a sealed testing chamber, opens the injection port, and uses a vacuum pump to evacuate the testing chamber and the inside of the battery. Then, the injection port is sealed, and helium gas is injected into the battery through the injection port (at this point, the battery is filled with helium, and the outside is a vacuum; if there is a leak, helium will escape into the vacuum testing chamber). Finally, a helium detector is used to measure the helium concentration in the chamber to determine whether the battery's sealing meets the standards. Although this method can detect minute leaks, it is difficult to accurately locate leaks in batteries with multiple leak points or complex structures.

[0004] To address the aforementioned issues, there is an urgent need for innovative designs based on existing lithium battery packaging sealing testing equipment. Summary of the Invention

[0005] This invention addresses the problem of overly simplistic solutions in existing technologies by providing a significantly different approach. Specifically, the invention aims to provide a lithium battery packaging sealing performance testing device and method. This addresses the shortcomings of the prior art, which focuses on testing the sealing performance of the casing without a sealing gasket, failing to adequately consider the potential impact of gasket wear on the sealing performance of lithium batteries during actual use. Furthermore, while existing testing methods can detect minor leaks, they struggle to accurately locate leaks in batteries with multiple leak points or complex structures.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a lithium battery packaging sealing test device, comprising an operating table, a battery casing with upper and lower liquid injection holes, and an air intake device for inputting gas, and further comprising a fixed cylinder for receiving air from the air intake device, a piston plate slidably disposed inside the fixed cylinder and driven by air pressure, an adjustment unit passively connected to the piston plate to simulate a state of damaged sealing of the battery casing, and a limiting unit passively connected to the piston plate to cooperate with the adjustment unit to change the sealing state of the battery casing;

[0007] A mixing mechanism for visualizing the sealing detection markers is provided between the adjustment unit and the fixed cylinder;

[0008] The mixing mechanism also includes a marking frame, which surrounds the seam between the sealing cap on the top of the battery housing and the opening of the battery housing.

[0009] Preferably, the lower end of the fixed cylinder is sealed and inserted into the liquid injection hole located at the lower position on the battery housing through a pipe, and a piston rod for driving the adjustment unit is fixed on one side of the piston plate.

[0010] Preferably, the adjustment unit includes a limiting frame, which is fixedly connected to the upper surface of the operating table. A driven slider is slidably limited inside the limiting frame, and the driven slider is fixedly connected to the outer end of the piston rod. A stop rod that slides through the upper end of the limiting frame is fitted to the upper surface of the driven slider. One end of a connecting frame is fixed to the upper end of the stop rod outside the limiting frame, and an upper magnet is fixed to the other end of the connecting frame.

[0011] The interior of the battery casing is used to house an elastic telescopic rod. The telescopic shaft end of the elastic telescopic rod is laterally slidably connected to a support frame. The top of the support frame is used to place a lower magnet and a sealing gasket in sequence. The side of the lower magnet opposite to the upper magnet has the same magnetic pole.

[0012] Preferably, a first spring is provided inside the limiting frame, one end of the first spring is fixed to one side of the driven slider, and the other end of the first spring is welded to the inner wall of the limiting frame.

[0013] The outer wall of the abutment is wound with a second spring. One end of the second spring is fixed to the top of the inner part of the limiting frame, and the other end of the second spring is welded to the top of the disc fixedly connected to the outer wall of the abutment.

[0014] Preferably, the upper surface of the driven slider is composed of three parts: a high plane, an inclined plane, and a low plane, and the lower end of the abutment is rotatably mounted with a roller that rolls with the upper surface of the driven slider.

[0015] Preferably, the limiting unit includes a sealing tube, one end of which is fixedly connected to the end of the fixed cylinder, and the other end of which is sealed and inserted into the liquid injection hole located at the upper position on the battery casing. A first sleeve is fixed inside the sealing tube, and a second sleeve is slidably connected inside the sealing tube, with one end of the first sleeve located inside the second sleeve. A rod is slidably connected inside the first sleeve, and a lifting plate is slidably connected inside the rod. A slot for limiting the position is opened on the surface of the telescopic shaft of the elastic telescopic rod to cooperate with the rod. A pressure plate is provided above the sealing cover of the battery casing, and the pressure plate is fixedly connected to the operating table through an electric push rod.

[0016] The lifting plate has a "Z" shaped design. The first sleeve has a limiting groove inside to limit the lifting of the lifting plate. One end of the second sleeve has two inclined surfaces that cooperate with the lifting of the lifting plate. The "Z" shaped lifting plate has a through rod.

[0017] Preferably, a third spring is provided inside the second sleeve, one end of the third spring is fixedly connected to the insertion rod, and the other end of the third spring is fixedly connected to the inner wall of the second sleeve.

[0018] Preferably, the mixing mechanism includes a storage tube disposed on one side of the limiting frame. The lower end of the storage tube is connected to the fixed cylinder through a pipe. The inner bottom surface of the storage tube is rotatably connected to a third sleeve with internal threads through a bearing. A lifting rod is slidably connected to the top of the storage tube. The lower end of the lifting rod is movably connected to the third sleeve through an external thread on its surface. The top end of the lifting rod is fixedly connected to the bottom of the connecting frame. A rotating blade is fixedly connected to the outer wall of the third sleeve.

[0019] A method for testing the sealing performance of lithium battery packaging, the method comprising the following steps:

[0020] S1. Place the battery casing in the detection position on the operating table. Seal the pipes below the sealing tube and the fixed cylinder and seal them with the upper and lower injection holes respectively. Place the elastic telescopic rod and the support frame inside the battery casing. Slide the elastic telescopic rod so that its slot engages with the rod. Place the lower magnet and the sealing gasket on the top of the support frame in sequence. Cover the battery casing with the sealing cover. Drive the pressure plate down to the upper surface of the sealing cover by the electric push rod.

[0021] S2. Gas is supplied into the fixed cylinder through the air intake device, which in turn drives the piston plate to move. When the piston plate moves past the pipe connecting the fixed cylinder and the battery casing, the gas enters the battery casing through the pipe. At this time, the gas inside the fixed cylinder and the storage tube is dispersed, thus depressurizing the inside. The fluorescent dye in the storage tube also enters the battery casing through the pipe under the action of gas pressure. The battery casing gradually fills with gas and fluorescent dye. At this time, due to the mutual squeezing of the pressure plate and the lower magnet, the airtightness detection of the battery casing is achieved under the condition that the sealing gasket is intact. If there is a leak in the battery casing, the fluorescent dye will fly to the inner wall of the transparent marking frame with the leaked gas and appear. The leak point can be determined by the position of the dye.

[0022] S3. The air intake device continuously supplies gas. When the air pressure inside the battery casing is balanced with the air pressure inside the fixed cylinder, the piston plate continues to move, driving the driven slider to slide. The push rod slides from the high plane to the low plane to move downward. The downward movement of the push rod drives the connecting frame and the upper magnet to move downward.

[0023] S4. When the piston plate moves to the end connected to the sealing tube, it pushes the second sleeve inside the sealing tube to slide. The second sleeve drives the lifting plate to move down in the limiting groove of the first sleeve through its two internal inclined surfaces. At the same time, with the help of the lifting plate's own "Z"-shaped structure, it pushes the insertion rod to move backward, releasing the limitation on the elastic telescopic rod. The elastic telescopic rod drives the support frame to move down, thereby releasing the limitation on the lower magnet. Since the upper magnet and the lower magnet are like poles and repel each other, the upper magnet moves down, causing the lower magnet to move down, thereby releasing the compression on the sealing gasket. This realizes the airtightness detection under the simulated state of the damaged sealing gasket. The fluorescent dye will fly to the inner wall of the transparent marking frame with the leaked gas and appear. The leak point can be determined by the position of the dye.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. Gas is supplied into the fixed cylinder through the air intake device. The air pressure pushes the piston plate to move inside the fixed cylinder. When the piston plate moves to the side of the sealing tube, it pushes the second sleeve inside the sealing tube to slide. The second sleeve drives the lifting plate to move down in the limiting groove of the first sleeve through two inclined surfaces inside. Since the lifting plate has a "Z" shaped structure, when it moves down, it drives the insertion rod to move backward, releasing the insertion rod from the limit of the elastic telescopic rod. This allows the elastic telescopic rod to drive the support frame to move down, thereby releasing the limit on the lower magnet. At this time, the compression of the sealing gasket between the battery casing and the lower magnet is released, thus simulating the state of the sealing gasket damage and achieving the effect of testing the sealing performance of the battery casing after a period of use.

[0026] 2. The piston plate moves, causing the driven slider to slide along a fixed path. The driven slider has an inclined structure, which facilitates the return force of the second spring to push the abutment rod downward, thereby driving the connecting frame to move downward synchronously. The downward movement of the connecting frame further drives the lifting rod to move downward. Since the lifting rod and the third sleeve are connected by threads, the linear motion of the lifting rod is converted into the rotational motion of the third sleeve. The rotation of the third sleeve causes the rotating blades on its outer wall to uniformly mix the fluorescent dye in the storage tube. When the pressure inside the fixed cylinder is released, the fluorescent dye in the storage tube enters the battery casing under the action of air pressure. By using the transparent marking frame fixed on the outside of the battery casing in conjunction with the fluorescent dye, it is possible to observe whether there is gas leakage, thereby detecting the airtightness of the battery casing. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the first three-dimensional structure of the present invention.

[0028] Figure 2 This is a schematic diagram of the second three-dimensional structure of the present invention.

[0029] Figure 3 This is a schematic diagram of the initial position structure of the pressure plate of the present invention.

[0030] Figure 4 This is a side sectional view of the pressure plate of the present invention moving to the top of the sealing cover.

[0031] Figure 5 This is a schematic diagram of the initial position structure of the piston plate of the present invention.

[0032] Figure 6 This is a schematic diagram of the piston plate of the present invention after its initial movement and subsequent stop.

[0033] Figure 7 For the present invention Figure 6 Enlarged view of the structure at point A.

[0034] Figure 8 This is a schematic diagram of the internal structure of the sealing cannula of the present invention.

[0035] Figure 9 This is a schematic diagram of the connection between the storage tube and the fixed cylinder of the present invention.

[0036] Figure 10 For the present invention Figure 9 Enlarged view of the structure at point B.

[0037] Figure 11 This is a unfolded view of the internal structure of the battery casing of the present invention.

[0038] In the diagram: 1. Control panel; 2. Battery casing; 301. Fixed cylinder; 302. Piston plate; 303. Piston rod; 304. Driven slider; 305. First spring; 4. Limiting frame; 501. Abutment rod; 502. Second spring; 503. Connecting frame; 504. Upper magnet; 601. Sealing tube; 602. First sleeve; 603. Second sleeve; 604. Third spring; 605. Insert rod; 606. Lifting plate; 701. Support frame; 702. Elastic telescopic rod; 703. Slot; 704. Lower magnet; 801. Storage tube; 802. Lifting rod; 803. Third sleeve; 804. Rotating blade; 9. Air intake device; 10. Pressure plate; 11. Marking frame. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Please see Figures 1 to 11 The lithium battery packaging sealing test device shown includes an operating table 1, a battery housing 2 with upper and lower liquid injection holes, and an air intake device 9 for inputting gas. It also includes a fixed cylinder 301 for receiving air from the air intake device 9, a piston plate 302 slidably disposed inside the fixed cylinder 301 and driven by air pressure, an adjustment unit driven by the piston plate 302 to simulate the sealed state of the battery housing 2 under damaged conditions, and a limiting unit driven by the piston plate 302 to cooperate with the adjustment unit to change the sealed state of the battery housing 2.

[0041] A mixing mechanism for visualizing the seal detection markers is provided between the adjusting unit and the fixed cylinder 301;

[0042] The mixing mechanism also includes a marking frame 11, which surrounds the joint between the sealing cover at the top of the battery housing 2 and the opening of the battery housing 2.

[0043] In specific implementation, gas is input into the fixed cylinder 301 through the air intake device 9, which drives the piston plate 302 to slide. The piston plate 302 drives the adjustment unit through a driven connection to simulate the detection of the battery housing 2 in a sealed state. The sealing state of the battery housing 2 is changed through the limit unit. A mixing mechanism is provided between the adjustment unit and the fixed cylinder 301 to mix the visual sealing detection marker. The marker frame 11 surrounds the joint between the battery housing 2 and the sealing cover. The sealing performance of the battery housing 2 is judged by observing the distribution of the marker in the marker frame 11.

[0044] As a further embodiment of the present invention, the lower end of the fixed cylinder 301 is sealed and inserted into the liquid injection hole located at the lower position on the battery housing 2 through a pipe, and a piston rod 303 for driving the adjustment unit is fixed on one side of the piston plate 302.

[0045] In practice, since the lower end of the fixed cylinder 301 is sealed and inserted into the liquid injection hole located at the lower position on the battery housing 2 through a pipe, the piston plate 302 moves under the drive of air pressure and drives the adjustment unit through the piston rod 303 fixed on one side, thereby simulating the change of the sealing state of the battery housing 2, which helps to test the sealing performance in the future.

[0046] As a further embodiment of the present invention, the adjustment unit includes a limiting frame 4, which is fixedly connected to the upper surface of the operating table 1. A driven slider 304 is slidably limited inside the limiting frame 4, and the driven slider 304 is fixedly connected to the outer end of the piston rod 303. A stop rod 501 is fitted to the upper surface of the driven slider 304 and slides through the upper end of the limiting frame 4. One end of the connecting frame 503 is fixed to the upper end of the stop rod 501 outside the limiting frame 4, and the other end of the connecting frame 503 is fixed with an upper magnet 504.

[0047] The interior of the battery casing 2 is used to house the elastic telescopic rod 702. The telescopic shaft end of the elastic telescopic rod 702 is slidably connected to a support frame 701. The top of the support frame 701 is used to place the lower magnet 704 and the sealing gasket in sequence. The side of the lower magnet 704 opposite to the upper magnet 504 has the same magnetic pole.

[0048] In practice, the piston rod 303 drives the driven slider 304 to move, which in turn drives the abutment rod 501 to move the position of the connecting frame 503, thereby causing the upper magnet 504 to move downward. Since the like poles of the upper magnet 504 and the lower magnet 704 repel each other, the lower magnet 704 moves downward synchronously, relieving the compression state on the sealing gasket, thereby achieving the purpose of simulating damage to the sealing gasket through the upper magnet 504.

[0049] As a further embodiment of the present invention, a first spring 305 is provided inside the limiting frame 4, and one end of the first spring 305 is fixed to one side of the driven slider 304, and the other end of the first spring 305 is welded to the inner wall of the limiting frame 4.

[0050] A second spring 502 is wound around the outer wall of the abutment rod 501. One end of the second spring 502 is fixed to the top of the inner part of the limiting frame 4, and the other end of the second spring 502 is welded to the top of the disc that is fixedly connected to the outer wall of the abutment rod 501.

[0051] In specific implementation, the first spring 305 connects the driven slider 304 and the inner wall of the limiting frame 4 to provide a reset force for the driven slider 304. The second spring 502 is wrapped around the outer wall of the abutment 501, with one end fixed to the top of the limiting frame 4 and the other end connected to the disc of the abutment 501. The lifting and lowering movement of the abutment 501 is controlled by the extension and retraction of the second spring 502.

[0052] As a further embodiment of the present invention, the upper surface of the driven slider 304 is composed of three parts: a high plane, an inclined plane and a low plane, and the lower end of the abutment 501 is rotatably mounted with a roller that rolls with the upper surface of the driven slider 304.

[0053] In specific implementation, the upper surface of the driven slider 304 is composed of a high plane, an inclined plane and a low plane. The abutment 501 rolls with the upper surface of the driven slider 304 through a roller installed at the lower end. When the driven slider 304 moves, the roller slides along the inclined plane, driving the abutment 501 to rise and fall, thereby adjusting the sealing state.

[0054] As a further embodiment of the present invention, the limiting unit includes a sealing tube 601. One end of the sealing tube 601 is fixedly connected to the end of the fixed cylinder 301, and the other end of the sealing tube 601 is sealed and inserted into the liquid injection hole located at the upper position on the battery housing 2. A first sleeve 602 is fixed inside the sealing tube 601, and a second sleeve 603 is slidably connected inside the sealing tube 601. One end of the first sleeve 602 is located inside the second sleeve 603. An insertion rod 605 is slidably connected inside the first sleeve 602, and a lifting plate 606 is slidably connected inside the insertion rod 605. A slot 703 is opened on the surface of the telescopic shaft of the elastic telescopic rod 702 to cooperate with the insertion rod 605 for limiting. A pressure plate 10 is provided above the sealing cover of the battery housing 2, and the pressure plate 10 is fixedly connected to the operating table 1 through an electric push rod.

[0055] The lifting plate 606 has a "Z" shaped design. The first sleeve 602 has a limiting groove inside to limit the lifting of the lifting plate 606. One end of the second sleeve 603 has two inclined surfaces that cooperate with the lifting of the lifting plate 606. The "Z" shaped lifting plate 606 passes through the insert rod 605.

[0056] In practice, one side of the sealing tube 601 is sealed and inserted into the liquid injection hole located at the top of the battery casing 2. When the piston plate 302 inside the fixed cylinder 301 is pressed and moves to one end of the second sleeve 603, pushing the second sleeve 603 to slide along the sealing tube 601, the sliding second sleeve 603, with the help of the two inclined surfaces at its end, pushes the "Z"-shaped lifting plate 606, causing the lifting plate 606 to move downward under force. At the same time, under the "Z"-shaped action of the lifting plate 606 itself, the insertion rod 605 is pulled into the sealing tube 601, causing the end of the insertion rod 605 to disengage from the slot 703, thereby releasing the insertion rod. The 605 limit on the elastic telescopic rod 702 facilitates the reset of the telescopic shaft of the elastic telescopic rod 702, causing the support frame 701 to move downward, thereby releasing the position restriction on the lower magnet 704. Utilizing the principle of like poles repulsion between the upper magnet 504 and the lower magnet 704, as the upper magnet 504 moves downward with the connecting frame 503, it causes the lower magnet 704 to move downward synchronously, thereby relieving the pressure of the lower magnet 704 on the sealing gasket and adjusting the sealing state of the battery casing 2. Subsequently, the electric push rod pushes the pressure plate 10 downward to press the sealing cover at the opening of the battery casing 2, ensuring the sealing performance during the testing process, thus facilitating subsequent airtightness testing.

[0057] As a further embodiment of the present invention, a third spring 604 is provided inside the second sleeve 603. One end of the third spring 604 is fixedly connected to the insertion rod 605, and the other end of the third spring 604 is fixedly connected to the inner wall of the second sleeve 603.

[0058] In the specific implementation, the third spring 604, in its initial state, facilitates the support of the insertion rod 605 and the second sleeve 603, allowing the opposite ends of the insertion rod 605 and the second sleeve 603 to extend to the outside of the sealing tube 601. This facilitates the subsequent engagement of the insertion rod 605 with the slot 703 and the pushing of the piston plate 302 on the second sleeve 603. As the piston plate 302 moves under pressure, it gradually pushes the second sleeve 603 along the inside of the sealing tube 601, thereby releasing the engagement of the insertion rod 605 with the slot 703 with the assistance of the lifting plate 606. After the airtightness test of the battery housing 2 is completed and the sealing cover is removed, the stretched first spring 305 returns to its original position, pulling the piston plate 302 to reset with the help of the driven slider 304 and the piston rod 303. When the piston plate 302 moves and releases the pressure on the second sleeve 603, the return of the third spring 604 pushes the insertion rod 605 to reset, thus facilitating the next airtightness test of the battery housing 2.

[0059] As a further embodiment of the present invention, the mixing mechanism includes a storage tube 801, which is disposed on one side of the limiting frame 4. The lower end of the storage tube 801 is connected to the fixed cylinder 301 through a pipe. The inner bottom surface of the storage tube 801 is rotatably connected to a third sleeve 803 with internal threads through a bearing. A lifting rod 802 is slidably connected to the top of the storage tube 801. The lower end of the lifting rod 802 is movably connected to the third sleeve 803 through an external thread on its surface. The top end of the lifting rod 802 is fixedly connected to the bottom of the connecting frame 503. A rotating blade 804 is fixedly connected to the outer wall of the third sleeve 803.

[0060] In practice, the connecting frame 503 drives the lifting rod 802 to rise and fall. The lifting rod 802 drives the third sleeve 803 to rotate through the thread. The third sleeve 803 drives the rotating blade 804 to uniformly mix the detection marker in the storage tube 801. The mixed marker enters the battery casing 2 through the pipe for visual sealing detection.

[0061] A method for testing the sealing performance of lithium battery packaging, the method comprising the following steps:

[0062] S1. Place the battery housing 2 in the detection position inside the operating table 1. Seal the pipes below the sealing tube 601 and the fixed cylinder 301 and seal them with the upper and lower injection holes respectively. Place the elastic telescopic rod 702 and the support frame 701 inside the battery housing 2. Slide the elastic telescopic rod 702 so that its slot 703 engages with the rod 605. Place the lower magnet 704 and the sealing gasket on the top of the support frame 701 in sequence. Cover the sealing cover of the battery housing 2. Drive the pressure plate 10 to descend to the upper surface of the sealing cover by the electric push rod.

[0063] S2. Gas is supplied into the fixed cylinder 301 through the air intake device 9, thereby driving the piston plate 302 to move. When the piston plate 302 moves past the pipe connecting the fixed cylinder 301 and the battery housing 2, the gas enters the battery housing 2 through the pipe. At this time, the gas inside the fixed cylinder 301 and the storage tube 801 is dispersed, thus depressurizing the inside. The fluorescent dye in the storage tube 801 also enters the battery housing 2 through the pipe under the action of air pressure. The battery housing 2 is gradually filled with gas and fluorescent dye. At this time, due to the mutual squeezing of the pressure plate 10 and the lower magnet 704, the airtightness detection of the battery housing 2 under the condition of intact sealing gasket is achieved. If there is a leak in the battery housing 2, the fluorescent dye will fly to the inner wall of the transparent marking frame 11 with the leaked gas and appear. The leak point can be determined by the position of the dye.

[0064] S3. The air intake device 9 continuously delivers gas. When the air pressure inside the battery housing 2 is balanced with the air pressure inside the fixed cylinder 301, the piston plate 302 continues to move, driving the driven slider 304 to slide. The push rod 501 slides from the high plane to the low plane to move downward. The downward movement of the push rod 501 drives the connecting frame 503 and the upper magnet 504 to move downward.

[0065] S4. When the piston plate 302 moves to the end connected to the sealing tube 601, it pushes the second sleeve 603 inside the sealing tube 601 to slide. The second sleeve 603 drives the lifting plate 606 to move down in the limiting groove of the first sleeve 602 through its two inclined surfaces. At the same time, with the help of the lifting plate 606's own "Z"-shaped structure, it pushes the insertion rod 605 to move backward, releasing the limitation on the elastic telescopic rod 702. The elastic telescopic rod 702 drives the support frame 701 to move down, thereby releasing the limitation on the lower magnet 704. Since the upper magnet 504 and the lower magnet 704 are like poles and repel each other, the upper magnet 504 moves down, causing the lower magnet 704 to move down, thereby releasing the compression on the sealing gasket. This realizes the airtightness detection under the simulated state of the damaged sealing gasket. The fluorescent dye will fly to the inner wall of the transparent marking frame 11 with the leaked gas and appear. The leak point can be determined by the position of the dye.

[0066] Working Principle: The battery casing 2 of this invention has a clearly defined injection hole for easy replenishment of electrolyte. During normal use, the sealing gasket is located between the battery casing 2 and the sealing cap. To simulate the sealing gasket's damaged state for airtightness testing, this invention places the sealing gasket at the internal joint between the sealing cap and the battery casing 2. By changing the degree of compression of the sealing gasket, the deformation of the sealing gasket is altered, facilitating the simulation of a damaged sealing gasket. When using this lithium battery packaging airtightness testing device, firstly, the lower end of the fixing cylinder 301 is sealed and inserted into the injection hole located at the lower position on the battery casing 2 through a pipe, and one side of the sealing insertion tube 601 is sealed and inserted into the injection hole located at the upper position on the battery casing 2. Secondly, the elastic telescopic rod 702 and its slidably connected support... The support frame 701 is placed inside the battery casing 2. The slot 703 of the sliding elastic telescopic rod 702 engages with the rod 605 slidably connected inside the sealing tube 601. The lower magnet 704 and the sealing gasket are placed on top of the support frame 701. The sealing cover of the battery casing 2 is placed on top of the sealing gasket. An electric push rod lowers the pressure plate 10 to the upper surface of the sealing cover of the battery casing 2 to compress it, preventing excessive atmospheric pressure inside the battery casing 2 from pushing the sealing cover upwards. Gas is supplied to the fixed cylinder 301 through the air intake device 9. At this time, the gas inside the fixed cylinder 301 is supplied to the storage tube 801 through the pipe fixedly connected to it, thus connecting the fixed cylinder 301 and the storage tube. The uniform air pressure inside 801 is designed to facilitate the dispersion of fluorescent dye from storage tube 801 into battery casing 2 during the instantaneous release of airflow from fixed cylinder 301 into battery casing 2 when piston plate 302 moves past the pipe below fixed cylinder 301. (It should be noted that the air supply from air inlet device 9 is slowly pressurized. At the instant the pipe opening below fixed cylinder 301 is exposed, the air supply from air inlet device 9 is less than the release from the pipe opening. At this moment, under the action of instantaneous pressure difference, the airflow actively disperses the fluorescent dye into battery casing 2. When the pressurization of air supply from air inlet device 9 exceeds the release from the pipe opening, the gas supplied by air inlet device 9 first replenishes the storage tube 801.) After the air pressure is reached, it will be continuously transported into the battery housing 2 through the pipe below the fixed cylinder 301. At the same time, it also facilitates the free dispersion of fluorescent dye inside the battery housing 2 under the influx of airflow, in preparation for observing the leak point when gas leaks inside the battery housing 2. After the storage tube 801 is filled with air pressure, the air intake device 9 continuously transports gas into the fixed cylinder 301. Under the drive of air pressure, the piston plate 302 is pushed to move along the inner wall of the fixed cylinder 301. While the piston plate 302 is moving, the piston rod 303 drives the driven slider 304 to slide inside the limit frame 4, thereby stretching the first spring 305. At the same time, the high plane at the top of the driven slider 304 slides over the rolling surface of the roller at the lower end of the abutment rod 501.

[0067] When the piston plate 302 slides inside the fixed cylinder 301 past the pipe below the fixed cylinder 301 that connects to the battery housing 2, the gas stored inside the fixed cylinder 301 flows into the battery housing 2 through the pipe. At this moment, the gas inside the fixed cylinder 301 is released instantaneously, and the gas stored inside the fixed cylinder 301 flows into the battery housing 2 through the pipe (the gas pressure inside the fixed cylinder 301 and the storage tube 801 remains the same), thereby depressurizing the inside of the fixed cylinder 301 and the storage tube 801. As the gas pressure flows, it drives the fluorescent dye inside the storage tube 801 to move. The material enters the fixed cylinder 301 through the pipe, and the lower end of the fixed cylinder 301 is sealed and inserted into the liquid injection hole located at the bottom of the battery housing 2 through the pipe. The battery housing 2 is gradually filled with gas and fluorescent dye. With the cooperation of the pressure plate 10 and the support frame 701, the battery housing 2 is in the airtightness test under the condition that the sealing gasket is not worn. If there is gas leakage in the battery housing 2 under this condition, the fluorescent dye will fly to the inner wall of the transparent marking frame 11 with the gas leakage and appear. Thus, the leakage point of the battery housing 2 can be determined by the position of the fluorescent dye.

[0068] Since the air intake device 9 is constantly supplying gas, when the air pressure inside the battery housing 2 is balanced with the air pressure inside the fixed cylinder 301, it will drive the piston plate 302 to continue moving. The piston plate 302 continues to move, which in turn drives the driven slider 304 to continue moving. As the driven slider 304 continues to move, when the inclined surface of the driven slider 304 passes over the roller at the lower end of the push rod 501, the compressed second spring 502 returns to its original state. With the restoring force of the second spring 502, the push rod 501, on which the roller is mounted, is pushed down to the driven slider 304. The lower plane of the rolling abutment 501 moves downward, causing the connecting frame 503 to move synchronously. This, in turn, causes the upper magnet 504 fixedly connected to the connecting frame 503 to move downward. At the same time, the movement of the connecting frame 503 causes the lifting rod 802 to move downward. Since the lifting rod 802 and the third sleeve 803 are threadedly connected, the downward movement of the lifting rod 802 causes the third sleeve 803 to rotate. This, in turn, causes the rotating blade 804 fixedly connected to the outer wall of the third sleeve 803 to rotate, uniformly mixing the fluorescent dye inside the storage tube 801.

[0069] As the piston plate 302 continues to move along the inside of the fixed cylinder 301 to the side connected to the sealing tube 601, the piston plate 302 first contacts one end of the second sleeve 603. The movement of the piston plate 302 pushes the second sleeve 603 to slide along the inside of the sealing tube 601. The sliding of the second sleeve 603, aided by its internal inclined surface, pushes the Z-shaped lifting plate 606 downwards. During the downward movement of the lifting plate 606, the insertion rod 605 is simultaneously driven to compress the third spring 604 and move into the sealing tube 601, causing the end of the insertion rod 605 to disengage from the slot 703, thereby releasing the elastic telescopic rod 702. The limit is set so that the telescopic shaft of the elastic telescopic rod 702 is reset, causing the support frame 701 to move downward, thereby releasing the limit on the lower magnet 704. Since the like poles of the upper magnet 504 and the lower magnet 704 repel each other, the lower magnet 704 moves downward by moving the upper magnet 504. At this time, the compression of the sealing gasket between the battery housing 2 and the lower magnet 704 is released, thereby simulating the state of damage to the sealing gasket of the battery housing 2. If there is also gas leakage in the battery housing 2 under this state, the fluorescent dye will also fly to the inner wall of the transparent marking frame 11 with the gas leakage and appear, thereby determining the leakage point of the battery housing 2 by the position of the fluorescent dye.

[0070] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium battery packaging airtightness testing device, comprising an operating table (1), a battery casing (2) with upper and lower liquid injection holes, and an air inlet device (9) for inputting gas, characterized in that: It also includes a fixed cylinder (301) for receiving air intake from the air intake device (9), a piston plate (302) slidably disposed inside the fixed cylinder (301) and driven by air pressure, an adjustment unit connected to the piston plate (302) to simulate the sealed state of the battery housing (2) under damage, and a limiting unit connected to the piston plate (302) to cooperate with the adjustment unit to realize the change of the sealed state of the battery housing (2); A mixing mechanism for visualizing the sealing detection marker is provided between the adjustment unit and the fixed cylinder (301); The mixing mechanism is also equipped with a marking frame (11), which surrounds the joint between the sealing cap provided on the top of the battery housing (2) and the opening of the battery housing (2); A piston rod (303) for driving the adjustment unit is fixed to one side of the piston plate (302). The adjustment unit includes a limiting frame (4), which is fixedly connected to the upper surface of the operating table (1). A driven slider (304) is slidably limited inside the limiting frame (4), and the driven slider (304) is fixedly connected to the outer end of the piston rod (303). A stop rod (501) is attached to the upper surface of the driven slider (304) and slides through the upper end of the limiting frame (4). One end of the connecting frame (503) is fixed at the upper end of the stop rod (501) outside the limiting frame (4), and the other end of the connecting frame (503) is fixed with an upper magnet (504). The interior of the battery casing (2) is used to place an elastic telescopic rod (702). The telescopic shaft end of the elastic telescopic rod (702) is laterally slidably connected to a support frame (701). The top of the support frame (701) is used to place a lower magnet (704) and a sealing gasket in sequence. The side of the lower magnet (704) opposite to the upper magnet (504) is a magnetic pole of the same polarity.

2. The lithium battery packaging sealing performance testing device according to claim 1, characterized in that: The lower end of the fixed cylinder (301) is sealed and inserted into the liquid injection hole located at the lower position on the battery casing (2) through a pipe.

3. The lithium battery packaging sealing performance testing device according to claim 1, characterized in that: The limiting frame (4) is provided with a first spring (305), one end of the first spring (305) is fixed to one side of the driven slider (304), and the other end of the first spring (305) is welded to the inner wall of the limiting frame (4); The outer wall of the abutment (501) is wrapped with a second spring (502). One end of the second spring (502) is fixed to the top of the inner part of the limiting frame (4), and the other end of the second spring (502) is welded to the top of the disc fixedly connected to the outer wall of the abutment (501).

4. The lithium battery packaging sealing performance testing device according to claim 1, characterized in that: The upper surface of the driven slider (304) is composed of three parts: a high plane, an inclined plane and a low plane, and the lower end of the abutment rod (501) is rotatably mounted with a roller that rolls with the upper surface of the driven slider (304).

5. The lithium battery packaging sealing performance testing device according to claim 1, characterized in that: The limiting unit includes a sealing tube (601), one end of which is fixedly connected to the end of the fixed cylinder (301), and the other end of which is sealed and inserted into the liquid injection hole located at the top position on the battery housing (2). A first sleeve (602) is fixed inside the sealing tube (601), and a second sleeve (603) is slidably connected inside the sealing tube (601). One end of the first sleeve (602) is located inside the second sleeve (603). A rod (605) is slidably connected inside the first sleeve (602), and a lifting plate (606) is slidably connected inside the rod (605). A slot (703) is provided on the surface of the telescopic shaft of the elastic telescopic rod (702) to limit the position of the rod (605). A pressure plate (10) is provided above the sealing cover of the battery housing (2), and the pressure plate (10) is fixedly connected to the operating table (1) by an electric push rod. The lifting plate (606) is designed in a "Z" shape. The first sleeve (602) has a limiting groove inside to limit the lifting of the lifting plate (606). The second sleeve (603) has two inclined surfaces at one end to cooperate with the lifting of the lifting plate (606). The "Z" shaped lifting plate (606) passes through the insert rod (605).

6. The lithium battery packaging sealing performance testing device according to claim 5, characterized in that: The second sleeve (603) is provided with a third spring (604), one end of the third spring (604) is fixedly connected to the insertion rod (605), and the other end of the third spring (604) is fixedly connected to the inner wall of the second sleeve (603).

7. The lithium battery packaging sealing performance testing device according to claim 6, characterized in that: The mixing mechanism includes a storage tube (801), which is located on one side of the limiting frame (4). The lower end of the storage tube (801) is connected to the fixed cylinder (301) through a pipe. The inner bottom surface of the storage tube (801) is rotatably connected to a third sleeve (803) with internal threads through a bearing. The top of the storage tube (801) is slidably connected to a lifting rod (802). The lower end of the lifting rod (802) is movably connected to the third sleeve (803) through an external thread on its surface. The top end of the lifting rod (802) is fixedly connected to the bottom of the connecting frame (503). A rotating blade (804) is fixedly connected to the outer wall of the third sleeve (803).

8. A method for detecting the airtightness of lithium battery packaging, applicable to the lithium battery packaging airtightness detection equipment described in claim 7, characterized in that, The detection method includes the following steps: S1. Place the battery housing (2) in the detection position inside the operating table (1). Seal the pipes below the sealing tube (601) and the fixed tube (301) and seal them with the upper and lower injection holes respectively. Place the elastic telescopic rod (702) and the support frame (701) inside the battery housing (2). Slide the elastic telescopic rod (702) so that its slot (703) engages with the rod (605). Place the lower magnet (704) and the sealing gasket on the top of the support frame (701) in sequence. Cover the sealing cover of the battery housing (2). Drive the pressure plate (10) to descend to the upper surface of the sealing cover by the electric push rod. S2. Gas is supplied to the fixed cylinder (301) through the air intake device (9), thereby driving the piston plate (302) to move. When the piston plate (302) moves past the pipe connecting the fixed cylinder (301) and the battery housing (2), the gas enters the battery housing (2) through the pipe. At this time, the gas inside the fixed cylinder (301) and the storage tube (801) is dispersed, thus depressurizing the inside. The fluorescent dye in the storage tube (801) also enters the battery housing (2) through the pipe under the action of air pressure. The battery housing (2) is gradually filled with gas and fluorescent dye. At this time, due to the mutual squeezing of the pressure plate (10) and the lower magnet (704), the airtightness detection of the battery housing (2) under the condition of intact sealing gasket is realized. If there is a leak in the battery housing (2), the fluorescent dye will fly to the inner wall of the transparent marking frame (11) with the leaked gas and appear. The leak point is determined by the dye position. S3. The air intake device (9) continuously delivers gas. When the air pressure inside the battery housing (2) is balanced with the air pressure inside the fixed cylinder (301), the piston plate (302) continues to move, driving the driven slider (304) to slide. The push rod (501) slides from the high plane to the low plane to move down. The downward movement of the push rod (501) drives the connecting frame (503) and the upper magnet (504) to move down. S4. When the piston plate (302) moves to the end connected to the sealing tube (601), it pushes the second sleeve (603) inside the sealing tube (601) to slide. The second sleeve (603) drives the lifting plate (606) to move downward in the limiting groove of the first sleeve (602) through its two inclined surfaces. At the same time, with the help of the "Z"-shaped structure of the lifting plate (606), it pushes the insertion rod (605) to move backward, releasing the limitation on the elastic telescopic rod (702). The telescopic rod (702) drives the support frame (701) to move down, thereby releasing the restriction on the lower magnet (704). Since the upper magnet (504) and the lower magnet (704) are like poles that repel each other, the upper magnet (504) moves down and drives the lower magnet (704) to move down, thereby releasing the pressure on the sealing gasket and realizing the airtightness detection under the simulated state of the damaged sealing gasket. The fluorescent dye will fly to the inner wall of the transparent marking frame (11) along with the leaked gas and appear. The leak point can be determined by the position of the dye.

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