A method for helium filling of pouch lithium batteries

Abstract

This invention discloses a method for helium-filling a pouch lithium battery, comprising: placing the cell structure to be helium-filled in a housing and sealing the housing; purging the air from the packaging bag of the cell structure and then injecting helium into the packaging bag; sealing the helium-filled packaging bag; evacuating the helium outside the sealing line and from the outer surface of the packaging bag; and removing the helium-filled cell structure from the housing, thus completing the helium-filling process. The helium-filling method for pouch lithium batteries provided by this invention enables sealed helium filling of the pouch battery, effectively preventing helium residue on the outer surface of the cell. After helium filling, the pouch lithium battery is placed in a sealed cavity, and a helium detector is used to check for leaks in the cell. Detecting helium leakage in the pouch lithium battery allows for accurate and rapid assessment of the packaging quality.

Description

Technical Field

[0001] This invention relates to the field of airtightness testing of soft lithium-ion batteries, specifically to a lithium-ion battery helium injection device, a method for helium injection into soft lithium-ion batteries, and a method for airtightness testing of soft lithium-ion batteries. Background Technology

[0002] Lithium-ion batteries are one of the most commonly used battery types in electric vehicles. Due to their high energy density and long cycle life, they have rapidly captured a large share of the electric vehicle battery market. Therefore, the performance of lithium-ion batteries directly impacts the overall performance of electric vehicles. Currently, lithium-ion power batteries mainly come in three types: cylindrical, pouch, and prismatic. Prismatic hard-shell batteries are widely used by power battery manufacturers due to their high safety performance and long cycle life.

[0003] Poor sealing of lithium batteries can lead to serious consequences such as severe performance degradation, electrolyte leakage, battery swelling, and even explosion, significantly impacting the lifespan and safety of lithium-ion batteries. Therefore, the quality of lithium battery sealing is crucial. Depending on the production process, sealing testing must be performed after battery packaging.

[0004] Currently, the battery evacuation and helium filling process mainly employs a pressure-reducing flow-controlled helium filling technology: First, the vacuum helium cup is lowered and sealed to the battery's filling port; then, the battery is evacuated, and helium gas is injected into the battery at a certain pressure. During the evacuation and helium filling process, the injection pressure and flow rate of the helium are adjusted by a pressure reducing valve and a throttle valve, respectively. A solenoid valve combined with a pressure gauge after helium filling controls the opening and closing of the helium filling pipeline, ultimately bringing the internal pressure of the battery close to atmospheric pressure. This method is suitable for cylindrical and prismatic batteries, as these two types of cells have filling ports, making them relatively convenient to use. However, soft lithium-ion batteries do not have filling ports. Due to technological limitations, currently only hard-pack batteries can be effectively tested for airtightness; there is still no accurate and rapid testing method for the airtightness of soft lithium-ion batteries. Summary of the Invention

[0005] The present invention provides a battery helium filling device to solve the above-mentioned technical problems.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is: a lithium battery helium filling device, the lithium battery helium filling device including a frame, a vacuum chamber disposed on the frame, a gas injection and exhaust mechanism disposed on the top of the vacuum chamber, a feeding mechanism mounted on the frame, and a clamping mechanism, a puncture mechanism, a stretching mechanism and a sealing mechanism disposed on the side wall of the vacuum chamber; the vacuum chamber includes a box body fixed on the frame and a cover plate slidably connected to the frame, the box body being fixed on the frame, and a positioning groove being provided at the bottom of the box body; the gas injection and exhaust mechanism is disposed on the cover plate.

[0007] Furthermore, a sealing ring is provided on the upper edge of the box.

[0008] Furthermore, a first support plate is provided above the cover plate, the first support plate is connected to the cover plate through a cover plate pressurization cylinder, and the first support plate is slidably connected to a first guide rail provided on the frame through a first slider; the first slider is connected to a cover plate drive cylinder.

[0009] Furthermore, the gas injection and exhaust mechanism includes a second support plate, which passes through the first support plate and is fixedly connected to the cover plate; a helium injection needle driving device is fixed on the second support plate, and a helium injection needle is connected below the helium injection needle driving device, with the lower end of the helium injection needle passing through the cover plate.

[0010] Furthermore, the helium injection needle drive device is provided with a first limiting device.

[0011] Furthermore, the feeding mechanism includes a lifting cylinder and a connecting plate. A second guide rail is fixed on the frame. The connecting plate is slidably connected to the second guide rail via a second slider. A robotic arm is connected to the lifting cylinder via the connecting plate. The robotic arm includes grippers and a gripper cylinder connected to the grippers.

[0012] Furthermore, a second limiting device is provided above the lifting cylinder.

[0013] Furthermore, the clamping mechanism includes pressure plates symmetrically arranged on both sides of the positioning groove and a pressure plate driving device connected to each of the pressure plates.

[0014] Furthermore, guide sleeves 6 are provided on both sides of the pressure plate driving device, and guide posts are sleeved on the guide sleeves and connected to the pressure plate.

[0015] Furthermore, the piercing mechanism includes at least one pair of convex and concave dies that fit each other in shape. The convex and concave dies are symmetrically arranged on both sides of the positioning groove. Both the convex and concave dies are connected to a piercing mechanism driving device. Both the convex and concave dies are provided with sealing devices. The convex die protrudes from the sealing device, and the concave die is concave towards the sealing device.

[0016] Furthermore, the shapes of the convex and concave dies are elliptical, circular, or square.

[0017] Furthermore, the sealing device is a sealing rubber.

[0018] Furthermore, the stretching mechanism includes at least two vacuum suction cups, which are symmetrically arranged on both sides of the clamping mechanism.

[0019] Furthermore, the packaging mechanism includes a sealing head, a sealing head driving device, a packaging plate, and a heating device. One end of the sealing head away from the clamping mechanism is connected to the sealing head driving device, the other end of the sealing head is connected to the packaging plate, and the packaging plate is connected to the heating device.

[0020] The lithium battery helium charging device provided by this invention includes a feeding mechanism that grasps a battery cell structure and places it in the positioning slot; a clamping mechanism that clamps the battery cell structure; a cover plate that slides along the frame to cover the housing and seal the vacuum chamber; a puncturing mechanism that punctures the packaging bag of the battery cell structure to create a puncture hole; the vacuum chamber begins to evacuate, and the air inside the packaging bag is discharged through the puncture hole; then, a sealing device seals the puncture hole; a stretching mechanism slightly pulls the packaging bag outward; a gas injection and exhaust mechanism injects helium into the packaging bag; the clamping force of the clamping mechanism is appropriately reduced to accommodate the expansion caused by the helium injection. The process involves several steps: first, a packaging bag is formed; then, a sealing mechanism seals the packaging bag along the outer edge of the battery cell. After the battery cell structure is sealed by the sealing mechanism, the airtightness of the packaging bag is effectively guaranteed. A second vacuum venting process removes helium from the outer surface of the packaging bag. Simultaneously, a gas injection and venting mechanism removes helium from the inside of the packaging bag outside the sealing line. This effectively prevents helium from adsorbing onto the surface of the battery cell structure, thus avoiding the impact of helium molecules adsorbed on the surface of the battery cell structure on the accuracy of subsequent leak detection, and improving the accuracy of helium detection for soft lithium-ion batteries. After vacuum venting, the vacuum chamber is opened, and a feeding mechanism removes the sealed battery cell structure from the vacuum chamber, cuts the packaging bag, and completes the helium injection. The lithium battery helium injection device provided by this invention can perform sealed helium filling inside a soft lithium-ion battery. The entire helium filling process effectively prevents helium residue from remaining on the outer surface of the battery cell. Using this lithium battery helium injection device to fill the soft lithium-ion battery with helium, and then placing the soft lithium-ion battery into a sealed cavity, a helium detector is used to detect whether there is a leak in the battery cell. Detecting helium leakage in pouch lithium batteries allows for accurate and quick assessment of the battery's packaging quality.

[0021] To solve the above-mentioned technical problems, the present invention also provides a method for injecting helium into a pouch lithium battery, wherein the above-mentioned lithium battery helium injection device is used to inject helium into the pouch lithium battery.

[0022] Furthermore, the soft-pack lithium battery includes one or more cell structures, each cell structure including a cell, each cell including two tabs and a middle region, the cell being packaged in a packaging bag, with one end of each tab extending out of the packaging bag.

[0023] Furthermore, the packaging bag is made of aluminum-plastic film.

[0024] Furthermore, the two electrodes are disposed on the same side of the battery cell, or the two electrodes are disposed on opposite sides of the battery cell.

[0025] Furthermore, the method for helium filling the pouch lithium battery includes the following steps:

[0026] Step 1, feeding and positioning: The feeding mechanism picks up the battery cell structure to be filled with helium and places it in the positioning slot. The clamping mechanism clamps the battery cell structure, and the cover plate seals the box.

[0027] Step 2, Puncture Hole: The puncturing mechanism punctures the packaging bag, creating a puncture hole;

[0028] Step 3, Exhausting: The vacuum chamber is evacuated to remove the air from the packaging bag, and then the puncture hole is sealed.

[0029] Step 4, Helium Injection: The stretching mechanism pulls the packaging bag outward, and the gas injection and degassing mechanism injects helium into the packaging bag;

[0030] Step 5: Packaging: The packaging mechanism seals the helium-filled packaging bag.

[0031] Step 7: Perform a second vacuuming to remove all helium outside the packaging line and from the outer surface of the packaging bag. Then, open the vacuum chamber and the feeding mechanism will remove the helium-injected battery cell structure from the vacuum chamber, completing the helium injection process.

[0032] Furthermore, step eight, cutting, involves cutting the packaging bag after the battery cell structure is removed from the vacuum box.

[0033] This invention also provides a method for helium filling a pouch lithium battery. The method involves using the aforementioned lithium battery helium filling device to fill the pouch lithium battery with helium, then placing the pouch lithium battery into a sealed cavity, and using a helium detector to check for leaks in the battery cells. Detecting helium leakage from the pouch lithium battery allows for accurate and rapid assessment of the pouch lithium battery's packaging quality.

[0034] To address the aforementioned technical problems, this invention also provides a method for testing the airtightness of a pouch lithium battery. The method involves using the aforementioned lithium battery helium filling device to fill the pouch lithium battery with helium, then placing the pouch lithium battery into a sealed cavity, and using a helium detector to check for leaks in the battery cells. Detecting helium leakage from the pouch lithium battery allows for accurate and rapid assessment of the pouch lithium battery's packaging quality. Attached Figure Description

[0035] Figure 1a This is a schematic diagram of a soft-pack lithium battery cell structure according to a specific embodiment of the present invention;

[0036] Figure 1b This is a schematic diagram of the battery cell structure after the puncturing mechanism punctures the packaging bag according to a specific embodiment of the present invention;

[0037] Figure 1c This is a schematic diagram of the battery cell structure of the packaging bag, which is a sealing device that seals the puncture hole according to a specific embodiment of the present invention and uses a vacuum suction cup to adsorb the packaging bag.

[0038] Figure 1d This is a schematic diagram of the cell structure after helium injection and cutting according to a specific embodiment of the present invention;

[0039] Figure 1e This is a schematic diagram of the cell structure of a soft-pack lithium battery according to another specific embodiment of the present invention;

[0040] Figure 2 This is an overall diagram of a helium injection device for a lithium battery according to a specific embodiment of the present invention;

[0041] Figure 3 This is a partial structural schematic diagram of a helium injection device for a lithium battery according to a specific embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the structure of the helium injection device for a lithium battery according to a specific embodiment of the present invention after the puncturing mechanism punctures the packaging bag 103;

[0043] Figure 5a This is a schematic diagram of a convex die structure according to a specific embodiment of the present invention;

[0044] Figure 5b This is a schematic diagram of a concave die structure according to a specific embodiment of the present invention. Detailed Implementation

[0045] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation methods, steps, structures, features, and effects of the battery helium injection device proposed according to the present invention.

[0046] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the accompanying drawings. Through the description of the specific embodiments, a more in-depth and specific understanding can be gained of the technical means and effects adopted by the present invention to achieve the intended purpose. However, the accompanying drawings are only provided for reference and illustration and are not intended to limit the present invention.

[0047] Please refer to Figure 1a , Figure 1b , Figure 1c , Figure 1d and Figure 1eA battery cell structure 100 includes a battery cell 101. The battery cell 101 has two tabs 102, which are located on the same side of the battery cell 101, or on opposite sides of the battery cell 101, i.e., one tab 102 on each side of the battery cell 101. The battery cell 101 is externally packaged in a packaging bag 103, with one end of each tab 102 extending beyond the packaging bag 103. The width of the packaging bag 103 is greater than the width of the battery cell 101. The portion of the packaging bag 103 wider than the battery cell 101 is used for subsequent processes such as puncturing, opening, helium injection, and sealing. The packaging bag 103 can be a packaging material such as aluminum-plastic film.

[0048] Please refer to this carefully. Figure 2 , Figure 3 and Figure 4 A helium-filling device 200 for lithium batteries can be used to fill the aforementioned cell structure 100 with helium.

[0049] The helium injection device for the lithium battery includes a frame 300, a vacuum chamber mounted on the frame 300, an injection and exhaust mechanism mounted on the top of the vacuum chamber, a feeding mechanism mounted on the frame, and a clamping mechanism, a puncture mechanism, a stretching mechanism, and a sealing mechanism mounted on the side wall of the vacuum chamber. The vacuum chamber includes a housing 401 fixed on the frame and a cover plate 402 slidably connected to the frame 300. The housing 401 is fixed on the frame 300, and a positioning groove 406 is provided at the bottom of the housing 401. The injection and exhaust mechanism is mounted on the cover plate 402.

[0050] The housing 401 is fixed on the frame 300, and the bottom of the housing 401 is provided with a positioning groove 406 for positioning the battery cell structure 100.

[0051] The working principle of the helium injection device 200 for the lithium battery is as follows: The feeding mechanism picks up the cell structure 100 and places it in the positioning groove 406. The clamping mechanism clamps the cell structure 100. The cover plate 402 slides along the frame 300, covering the box 401 and sealing the vacuum box. The piercing mechanism pierces the packaging bag 103 of the cell structure 100, creating a piercing hole 104. The vacuum box begins to evacuate, and the air in the packaging bag 103 is discharged through the piercing hole 104 and completely expelled. Then, the sealing device 704 seals the piercing hole 104. The stretching mechanism slightly pulls the packaging bag 103 outward, and the gas injection and degassing mechanism injects gas into the packaging bag. Helium is injected into the packaging bag 103, and the clamping force of the clamping mechanism is appropriately reduced to accommodate the helium-injected packaging bag 103. Then, the packaging mechanism seals the packaging bag 103 along the outer edge of the battery cell 101. A second vacuum is performed to remove helium from the outer surface of the packaging bag 103. At the same time, the helium inside the packaging bag 103 outside the sealing line 105 is removed by the gas injection and degassing mechanism. This effectively avoids helium adsorption, thereby preventing the helium molecules adsorbed on the surface of the battery cell structure 100 from affecting the accuracy of subsequent leak testing and improving the accuracy of helium testing for soft lithium-ion batteries. After the vacuum degassing is completed, the vacuum box is opened, and the feeding mechanism removes the packaged battery cell structure 100 from the vacuum box, cuts the packaging bag 103, and completes the helium injection.

[0052] A first support plate 404 is disposed above the cover plate 402. The first support plate 404 is connected to the cover plate 402 via a cover plate pressurizing cylinder 405. The first support plate 404 is slidably connected to a first guide rail 301 disposed on the frame 300 via a first slider 302. The first slider 302 is connected to a cover plate driving cylinder (not shown in the figure). The cover plate driving cylinder drives the first slider 302 to move the first support plate 404 along the first guide rail 301, thereby moving the cover plate 402 to slide directly above the housing 401. Then, the cover plate pressurizing cylinder 405 drives the cover plate 402 to press down on the housing 401, sealing the vacuum chamber. A sealing ring 403 is provided on the upper edge of the housing 401 to further enhance the sealing of the vacuum chamber and prevent air leakage. After the packaging mechanism encapsulates the cell structure 100, the cover plate 402 returns to its original position.

[0053] The gas injection and exhaust mechanism includes a second support plate 1001, which passes through the first support plate 404 and is fixedly connected to the cover plate 402. A helium injection needle driving device 1002 is fixed on the second support plate 1001, and a helium injection needle 1003 is connected below the helium injection needle driving device 1002. The lower end of the helium injection needle 1003 passes through the cover plate 402. When the cover plate 402 covers the housing 401, the helium injection needle 1003 is directly facing the positioning groove 406 inside the housing 401, that is, directly facing the top of the battery cell structure 100 to be filled with helium. A first limiting device 1004 is provided on the helium injection needle 1003 driving device 1002 to limit the area of ​​movement of the helium injection needle 1003, ensuring that the helium injection needle 1003 accurately pierces the packaging bag 103 and avoids the helium injection needle 1003 piercing the battery cell 101.

[0054] The working principle of the gas injection and venting mechanism is as follows: The helium injection needle driving device 1002 drives the helium injection needle 1003 to pierce the packaging bag 103, and the helium injection needle 1003 injects helium into the packaging bag 103. After the packaging mechanism encapsulates the cell structure 100, a second vacuum venting is performed. The helium inside the packaging bag 103 outside the packaging line 105 is completely removed by the gas injection and venting mechanism, which can effectively avoid helium adsorption. This avoids the influence of helium molecules adsorbed on the surface of the cell structure 100 on the accuracy of subsequent leak detection, and is beneficial to improving the accuracy of helium detection for soft lithium-ion batteries. After the vacuum venting is completed, the helium injection needle 1003 retracts, and then the vacuum chamber is opened.

[0055] Please refer to this carefully. Figure 2 , Figure 3 and Figure 4 The feeding mechanism is used to convey the battery cell structure 100. The feeding mechanism includes a lifting cylinder 501 and a connecting plate 502. A second guide rail 303 is fixed on the frame 300, and the connecting plate 502 is slidably connected to the second guide rail 303 via a second slider 304. A robotic arm is connected to the lifting cylinder 501 via the connecting plate 502. The robotic arm includes grippers and a gripper cylinder 505 connected to the grippers. A second limiting device 506 is provided above the lifting cylinder 501 to limit the lifting area of ​​the robotic arm, thereby limiting the position of the battery cell structure 100.

[0056] The feeding mechanism works as follows: the gripper cylinder 505 drives the gripper to clamp the battery cell structure 100, sliding it along the second guide rail 303 to directly above the housing 401. The lifting cylinder 501 drives the robotic arm to descend via the connecting plate 502, delivering the battery cell structure 100 to the positioning slot 406 inside the vacuum chamber. The feeding mechanism then returns to its original position. After the helium injection process is completed, the gripper cylinder 505 drives the gripper to clamp the battery cell structure 100, and the lifting cylinder 501 drives the robotic arm to rise, transferring the battery cell structure 100 to the next process. Two robotic arms can be provided to facilitate maintaining material balance during material handling.

[0057] Please refer to this carefully. Figure 2 , Figure 3 and Figure 4 The clamping mechanism includes two pressure plates 601 symmetrically arranged on both sides of the positioning groove 406 and a pressure plate driving device 602 connected to each of the pressure plates 601. The pressure plate driving device 602 drives the two pressure plates 601 to move towards each other, clamping the battery cell structure 100. The position of the pressure plates 601 faces upwards from the positioning groove 406. The portion of the packaging bag 103 wider than the pressure plates 601 is used for puncturing and opening in subsequent processes.

[0058] Please refer to this carefully. Figure 4 The pressure plate driving device 602 is provided with guide sleeves 603 on both sides. The guide sleeves 603 are sleeved with guide posts 604. The guide posts 604 are connected to the pressure plate. The pressure plate driving device 602 drives the guide sleeves 603 to slide along the guide posts 604, which can effectively ensure the smooth movement of the pressure plate.

[0059] Please refer to Figure 1b and 1c , Figure 2 , Figure 3 and Figure 4 , combined Figure 5a and Figure 5b , Figure 1b This is a schematic diagram of the battery cell structure 100 after the puncturing mechanism punctures the packaging bag 103; Figure 1c The diagram shows the structure of the battery cell where the sealing device 704 seals the puncture hole 104 and the vacuum suction cup 801 adsorbs the packaging bag 103. Figure 4This is a schematic diagram of the structure of the helium filling device for lithium batteries after the puncture mechanism punctures the packaging bag 103. The puncture mechanism is used to puncture the packaging bag 103, creating a puncture hole 104 on the packaging bag 103, which is used to release the gas inside the packaging bag 103. The puncture mechanism includes at least one pair of convex dies 701 and concave dies 702 that fit together. The convex dies 701 and the concave dies 702 are symmetrically arranged on both sides of the positioning groove 406, and the convex dies 701 and the concave dies 702 point towards the upper edge of the packaging bag 103. Both the convex dies 701 and the concave dies 702 are connected to a puncture mechanism driving device 703. Both the convex dies 701 and the concave dies 702 are provided with sealing devices 704. The convex die 701 protrudes from the sealing device 704, and the concave die 702 is concave towards the sealing device 704. The convex dies 701 and the concave dies 702 can be any shape such as ellipse, circle, or square. The sealing device 704 can be a sealing rubber, and the sealing device 704 is used to seal the holes cut by the convex dies 701 and the concave dies 702. The convex die 701 is organically combined with the sealing rubber, and the concave die 702 is organically combined with the sealing rubber, so that a single device can simultaneously perform both puncture and sealing functions.

[0060] The working principle of the puncture mechanism is as follows: The puncture mechanism driving device 703 drives the convex die 701 and the concave die 702 to move towards the battery cell structure 100. The convex die 701 and the concave die 702 work together to puncture the upper edge of the packaging bag 103, creating a puncture hole 104. The shape of the puncture hole 104 is the same as the shape of the convex die 701 and the concave die 702. The puncture hole 104 is used to discharge the gas inside the packaging bag 103 during the vacuuming process of the vacuum chamber; creating a puncture hole 104 After 04, the convex die 701 and the concave die 702 return to their original positions, the vacuum box is evacuated, and the gas in the packaging bag 103 is discharged through the puncture hole 104. After the gas in the packaging bag 103 is discharged, the puncture mechanism driving device 703 drives the convex die 701 and the concave die 702 to move toward the cell structure 100. The sealing device 704 on the convex die 701 and the concave die 702 seals the puncture hole 104 to prevent the helium in the packaging bag 103 from leaking during the helium injection process.

[0061] Please refer to this carefully. Figure 2 , Figure 3 and Figure 4The stretching mechanism includes at least two vacuum suction cups 801 and a vacuum suction cup driving device 802 connected to the vacuum suction cups 801. The vacuum suction cups 801 are positioned in the middle of the packaging bag 103. The stretching mechanism may also be provided with two vacuum suction cups 801, which are symmetrically arranged on both sides of the clamping mechanism, that is, on both sides of the cell structure 100 to be filled with helium.

[0062] The working principle of the stretching mechanism is as follows: the vacuum suction cup driving device 802 drives the vacuum suction cup 801 to adsorb the outer surface of the packaging bag 103, and then the vacuum suction cup driving device 802 drives the vacuum suction cup 801 to pull the packaging bag 103 apart by a certain distance, and the packaging bag 103 undergoes a certain degree of deformation, which facilitates the injection of helium into the packaging bag 103.

[0063] Please refer to Figure 1d and Figure 4 , Figure 1d This is a schematic diagram of the cell structure 100 after helium injection and cutting. The packaging mechanism is used to package the cell structure 100 after helium injection. The packaging mechanism includes a cap 901, a cap driving device 902, a packaging plate 903, and a heating device (not shown in the figure). One end of the cap 901 away from the clamping mechanism is connected to the cap driving device 902, and the other end of the cap 901 is connected to the packaging plate 903. The packaging plate 903 is connected to the heating device, which is used to heat the packaging plate 903. The sealing head driving device 902 drives the sealing head 901 to move towards the packaging bag 103, thereby achieving heat sealing of the packaging bag 103. The sealing line 105 is along the outer edge of the battery cell. The puncture hole 104 generated by the puncture mechanism and the packaging bag 103 adsorbed by the vacuum suction cup 801 of the stretching mechanism are both outside the sealing line 105. After the battery cell structure 100 is sealed by the sealing mechanism, the airtightness of the packaging bag 103 can be effectively guaranteed.

[0064] The lithium battery helium filling device 200 provided by this invention can perform sealed helium filling of the interior of a soft lithium battery pack. The entire helium filling process effectively prevents helium residue from remaining on the outer surface of the battery cell. After filling the soft lithium battery pack with helium using this device, the soft lithium battery pack is placed in a sealed cavity, and a helium detector is used to check for leaks in the battery cell. Detecting helium leakage in the soft lithium battery allows for accurate and quick assessment of the packaging quality.

[0065] A method for injecting helium into a pouch lithium battery, using the aforementioned lithium battery helium injection device 200 to inject helium gas into the pouch lithium battery, includes the following steps:

[0066] Step 1, feeding: The feeding mechanism picks up the battery cell structure 100 and places the battery cell structure 100 in the positioning groove. The clamping mechanism clamps the battery cell structure 100 and the cover plate 402 covers the box 401.

[0067] Step 2, puncture: The puncturing mechanism punctures the packaging bag 103, creating a puncture hole 104;

[0068] Step 3, Exhausting: The vacuum chamber is evacuated, and the air in the cell structure 100 is discharged through the puncture hole 104 until it is completely exhausted.

[0069] Step 4: The sealing device 704 seals the puncture hole 104;

[0070] Step 5, Helium Injection: The stretching mechanism pulls the packaging bag 103 of the battery cell structure 100 outward a certain distance, causing the packaging bag 103 to deform to a certain extent. The helium injection needle injects helium into the packaging bag 103. At the same time, the pressure of the clamping mechanism plate 601 decreases, which works in conjunction with the packaging bag 103 that bulges due to the injection of helium.

[0071] Step 6, Packaging: The packaging mechanism packages the packaging bag 103 along the outer edge of the battery cell 101, which can be done by heat sealing; the packaging line 105 is along the edge of the battery cell, and the piercing hole 104 and the packaging bag position adsorbed by the vacuum suction cup 801 are all outside the packaging line 105. After the packaging bag 103 is further packaged, the airtightness of the battery cell structure 100 can be effectively guaranteed.

[0072] Step 7, Second Vacuum Exhaust: The gas injection and exhaust mechanism removes residual helium from the packaging bag 103 outside the sealing line 105, effectively preventing helium adsorption and thus avoiding the impact of helium molecules adsorbed on the surface of the cell structure 100 on the accuracy of subsequent leak testing, which is beneficial to improving the accuracy of helium testing for soft lithium-ion batteries. After vacuum exhaust, the helium injection needle 1003 retracts, and then the vacuum chamber is opened. This also removes helium from the entire outer surface of the packaging bag 103, effectively preventing helium adsorption on the inner and outer surfaces of the packaging bag 103, thus avoiding the impact of helium molecules adsorbed on the surface of the cell structure 100 on the accuracy of subsequent leak testing, which is beneficial to improving the accuracy of helium testing for soft lithium-ion batteries. After vacuum exhaust, the gas injection and exhaust mechanism, puncture mechanism, and stretching mechanism all retract to their original positions.

[0073] Step 8, Cutting: Open the vacuum chamber. The robotic arm of the feeding mechanism grips the packaging bag 103. The gripping mechanism retracts to its original position, and the feeding mechanism removes the packaged battery cell structure 100 from the vacuum chamber. The battery cell structure 100 is then transferred to the cutting station to cut the packaging bag. Alternatively, a cutting tool can be used for cutting. After cutting, any excess packaging bag 103 can be folded towards the battery cell 101, resulting in a neater battery cell structure and better airtightness.

[0074] A method for testing the airtightness of a pouch lithium battery involves filling the pouch lithium battery with helium using the aforementioned lithium battery helium filling device, then placing the pouch lithium battery into a sealed cavity, and using a helium detector to check for leaks in the battery cells. Detecting helium leakage in pouch lithium batteries allows for accurate and rapid assessment of the packaging quality.

[0075] The above description is merely a preferred embodiment of the invention and is not intended to limit the invention in any way. Although the invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the invention without departing from the scope of the invention shall still fall within the scope of the invention.

Claims

1. A method for helium injection into a pouch lithium battery, characterized in that, The helium-filling device used in the method for helium-filling soft-pack lithium batteries includes a frame, a vacuum chamber mounted on the frame, a gas injection and venting mechanism mounted on the top of the vacuum chamber, a feeding mechanism mounted on the frame, and a clamping mechanism, a puncture mechanism, a stretching mechanism, and a sealing mechanism mounted on the side wall of the vacuum chamber. The vacuum chamber includes a housing fixed to the frame and a cover plate slidably connected to the frame. The housing is fixed to the frame, and a positioning groove is provided at the bottom of the housing. The gas injection and venting mechanism is mounted on the cover plate. The puncture mechanism includes at least one pair of mutually matching convex and concave dies. The convex die and the concave die are symmetrically arranged on both sides of the positioning groove. Both the convex die and the concave die are connected to a puncture mechanism drive device. Each of the convex die and the concave die is provided with a sealing device; the convex die protrudes from the sealing device, and the concave die is recessed towards the sealing device. A sealing ring is provided on the upper edge of the housing. A first support plate is provided above the cover plate, and the first support plate is connected to the cover plate via a cover plate pressurization cylinder. The first support plate is slidably connected to a first guide rail provided on the frame via a first slider. The first slider is connected to a cover plate drive cylinder. The method for injecting helium into the soft-pack lithium battery includes... Place the cell structure to be filled with helium into the housing and seal the housing; After purging the air from the packaging bag containing the battery cell structure, helium gas is injected into the packaging bag. The helium-injected packaging bag is sealed, and the helium outside the sealing line and on the outer surface of the packaging bag is evacuated. The helium-injected cell structure is then removed from the casing, completing the helium injection process. Helium is then injected into the soft-pack lithium battery using a lithium battery helium injection device. The lithium battery helium injection device includes an injection and venting mechanism, a feeding mechanism, a clamping mechanism, a puncture mechanism, a stretching mechanism, and a packaging mechanism, and includes the following steps: Step 1, feeding and positioning: The feeding mechanism picks up the battery cell structure to be filled with helium and places it in the positioning slot. The clamping mechanism clamps the battery cell structure, and the cover plate seals the box. Step 2, Puncture Hole: The puncturing mechanism punctures the packaging bag, creating a puncture hole; Step 3, Exhausting: The vacuum chamber is evacuated to remove the air from the packaging bag, and then the puncture hole is sealed. Step 4, Helium Injection: The stretching mechanism pulls the packaging bag outward, and the gas injection and degassing mechanism injects helium into the packaging bag; Step 5: Packaging: The packaging mechanism seals the helium-filled packaging bag. Step Six: Perform a second vacuuming to remove all helium outside the packaging line and from the outer surface of the packaging bag. Then, open the vacuum chamber and the feeding mechanism will remove the helium-injected battery cell structure from the vacuum chamber, completing the helium injection process.

2. The method for helium injection into a soft-pack lithium battery as described in claim 1, characterized in that, It also includes cutting the packaging bag after the battery cell structure is removed from the box.

3. The method for helium injection into a soft-pack lithium battery as described in claim 1, characterized in that, The gas injection and exhaust mechanism includes a second support plate, which passes through the first support plate and is fixedly connected to the cover plate; a helium injection needle driving device is fixed on the second support plate, and a helium injection needle is connected below the helium injection needle driving device, with the lower end of the helium injection needle passing through the cover plate.

4. The method for helium injection into a soft-pack lithium battery as described in claim 3, characterized in that, The helium injection needle drive device is equipped with a first limiting device.

5. The method for helium injection into a soft-pack lithium battery as described in claim 1, characterized in that, The feeding mechanism includes a lifting cylinder and a connecting plate. A second guide rail is fixed on the frame. The connecting plate is slidably connected to the second guide rail via a second slider. A robotic arm is connected to the lifting cylinder via the connecting plate. The robotic arm includes grippers and a gripper cylinder connected to the grippers.

6. The method for helium injection into a soft-pack lithium battery as described in claim 5, characterized in that, A second limiting device is provided above the lifting cylinder.

7. The method for helium injection into a soft-pack lithium battery as described in claim 1, characterized in that, The clamping mechanism includes pressure plates symmetrically arranged on both sides of the positioning groove and a pressure plate driving device connected to each of the pressure plates.

8. The method for helium injection into a soft-pack lithium battery as described in claim 7, characterized in that, The pressure plate driving device is provided with guide sleeves on both sides, and guide posts are sleeved on the guide sleeves and connected to the pressure plate.

9. The method for helium injection into a soft-pack lithium battery as described in claim 1, characterized in that, The convex and concave dies are elliptical, circular, or square in shape.

10. The method for helium injection into a pouch lithium battery as described in claim 1, characterized in that, The stretching mechanism includes at least two vacuum suction cups, which are symmetrically arranged on both sides of the clamping mechanism.

11. The method for helium injection into a pouch lithium battery as described in claim 1, characterized in that, The packaging mechanism includes a sealing head, a sealing head driving device, a packaging plate, and a heating device. One end of the sealing head away from the clamping mechanism is connected to the sealing head driving device, and the other end of the sealing head is connected to the packaging plate. The packaging plate is connected to the heating device.

12. The method for helium injection into a pouch lithium battery as described in any one of claims 1-11, characterized in that, The soft-pack lithium battery includes one or more cell structures. The cell structure includes a cell, the cell includes two tabs and a middle region, and the cell is wrapped in a packaging bag. One end of the tab extends out of the packaging bag.

13. The method for helium injection into a pouch lithium battery as described in claim 12, characterized in that, The packaging bag is made of aluminum-plastic film.

14. The method for helium injection into a pouch lithium battery as described in claim 12, characterized in that, The two electrodes are disposed on the same side of the battery cell, or the two electrodes are disposed on opposite sides of the battery cell.

15. A method for testing the airtightness of a soft-pack lithium battery, characterized in that, The soft-pack lithium battery is filled with helium using the method of helium filling according to any one of claims 1-14. Then, the soft-pack lithium battery is placed in a sealed cavity, and a helium detector is used to detect whether there is leakage in the battery cell and to detect the leakage of helium gas from the soft-pack lithium battery.

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