Head structure

Abstract

The utility model discloses a kind of end structure. The end structure includes being applied to soft pack battery, and is sealedly arranged in aluminium plastic film air bag, the end structure is provided with accommodating cavity, the accommodating cavity is used to accommodate electrolyte, the end structure is provided with weak part, the thickness of the weak part is less than the thickness of the end structure. Under external force, the weak part cracks, to make the electrolyte in the accommodating cavity flow into the body of the soft pack battery through the aluminium plastic film air bag. The end structure of the application pre-contains secondary electrolyte by accommodating cavity, without additional cutting open aluminium plastic film and injecting electrolyte in secondary liquid injection stage, only need to extrude weak part by external force to complete electrolyte injection, save the procedure of secondary liquid injection. The structure can complete the sealing forming of accommodating cavity and secondary electrolyte filling simultaneously in primary liquid injection workshop, without cross workshop transfer, greatly shorten circulation time, significantly improve production efficiency.

Description

Technical Field

[0001] This utility model relates to the technical field of battery equipment, and in particular to a head structure. Background Technology

[0002] In the lithium battery manufacturing process, the feasibility and safety of pouch cells are crucial, especially in the electrolyte injection process (including secondary electrolyte injection). In existing technologies, the secondary electrolyte injection method for pouch cells typically involves cutting the aluminum-plastic film, injecting secondary electrolyte, and vacuum sealing to complete the secondary electrolyte injection.

[0003] There are different processes between the first and second electrolyte injection, requiring batteries to be transferred between different workshops, resulting in low time efficiency. The second electrolyte injection method involves cumbersome processes such as cutting the aluminum-plastic film, injecting the second electrolyte, and vacuum sealing, which reduces production efficiency. Utility Model Content

[0004] The main purpose of this utility model is to provide a sealing head structure that aims to solve the technical problem of cumbersome secondary liquid injection process and reduced production efficiency in soft-pack batteries.

[0005] In order to achieve the above-mentioned utility model objectives, this utility model proposes a head structure.

[0006] A sealing structure is used in a soft-pack battery and is sealed inside an aluminum-plastic film air bag. The sealing structure has a receiving cavity for containing electrolyte. The sealing structure has a weak part, the thickness of which is less than the thickness of the sealing structure. Under the action of external force, the weak part cracks, so that the electrolyte in the accommodating cavity flows into the body of the soft-pack battery through the aluminum-plastic film air bag.

[0007] In one embodiment, the end cap structure includes a first segment, a second segment, and a third segment. One end of the second segment is connected to the first segment, and the other end of the second segment is connected to the third segment. The first segment and the third segment are disposed opposite to each other, and the weak part is disposed in the second segment.

[0008] In one embodiment, the end cap structure is a U-shaped structure.

[0009] In one embodiment, the minimum thickness of the weak portion is 1 / 4 to 1 / 3 of the thickness of the head structure.

[0010] In one embodiment, the weak point is a groove in the inner wall of the end cap structure.

[0011] In one embodiment, the groove includes a first groove wall and a second groove wall, the connection point of the first groove wall and the second groove wall is the minimum thickness of the weak part, and the first groove wall and the second groove wall are inclined.

[0012] In one embodiment, the weak point is a V-shaped structure; or The weak part is a circular arc structure.

[0013] In one embodiment, the weak point is located at the bottom of the head structure.

[0014] In one embodiment, the end cap structure is located at the middle of the length of the aluminum-plastic film air bag.

[0015] In one embodiment, two end cap structures are provided, with the two end cap structures respectively located on the front and back of the aluminum-plastic film air bag.

[0016] Beneficial effects: This invention discloses a sealing structure for use in soft-pack batteries, sealed within an aluminum-plastic film air bag. The sealing structure includes a accommodating cavity for holding electrolyte. The sealing structure has a weak point, the thickness of which is less than the overall thickness of the sealing structure. Under external force, the weak point cracks, allowing the electrolyte in the accommodating cavity to flow into the soft-pack battery body through the aluminum-plastic film air bag. This sealing structure pre-contains secondary electrolyte within the accommodating cavity, eliminating the need for additional cutting of the aluminum-plastic film and electrolyte injection during the secondary electrolyte injection stage. Electrolyte injection is completed simply by pressing the weak point, eliminating the need for a secondary electrolyte injection process. This structure allows for simultaneous sealing and forming of the accommodating cavity and filling of the secondary electrolyte in the primary electrolyte injection workshop, eliminating the need for inter-workshop transfer, significantly shortening turnaround time and greatly improving production efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a soft-pack battery according to an embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the end cap structure according to an embodiment of the present invention.

[0019] in: 100. Head structure; 110. Receiving cavity; 120. Weak section; 121. First groove wall; 122. Second groove wall; 130. First section; 140. Second section; 150. Third section; 200. Aluminum-plastic film air bag; 300, soft-pack battery.

[0020] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0021] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0022] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly and specifically defined.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0025] like Figure 1 and Figure 2As shown, in some embodiments, a cap structure 100 is applied to a pouch battery 300 and is sealed within an aluminum-plastic film air bag 200. The cap structure 100 has a accommodating cavity 110 for accommodating electrolyte. The cap structure 100 has a weak portion 120, the thickness of which is less than the thickness of the cap structure 100. Under external force, the weak portion 120 cracks, allowing the electrolyte in the accommodating cavity 110 to flow into the pouch battery 300 through the aluminum-plastic film air bag 200.

[0026] During operation, after the soft-pack battery 300 has undergone its first electrolyte injection, a pre-prepared end cap structure 100 is placed in a predetermined position within an aluminum-plastic film air bag 200 in the same injection workshop. Using a heat-sealing device with adjustable temperature and pressure, the end cap structure 100 and the aluminum-plastic film air bag 200 are heat-sealed together to form a sealed space. Subsequently, a predetermined amount of secondary electrolyte is injected into the accommodating cavity 110 through the injection port (sealed after injection) of the end cap structure 100, completing the initial assembly. When secondary electrolyte injection is required, a special extrusion device applies external force to the weak point 120 of the end cap structure 100, causing it to crack. The secondary electrolyte in the accommodating cavity 110 flows along the cracked channel through the aluminum-plastic film air bag 200 into the soft-pack battery 300 body. Once the electrolyte has completely flowed in, the secondary electrolyte injection process ends, and the battery packaging process begins.

[0027] The end cap structure 100 of this application pre-fills the secondary electrolyte through the accommodating cavity 110, eliminating the need for additional cutting of the aluminum-plastic film and injection of electrolyte during the secondary electrolyte injection stage. Electrolyte injection can be completed simply by externally pressing the weak part 120, thus eliminating the secondary electrolyte injection process. This structure allows the sealing and molding of the accommodating cavity 110 and the filling of the secondary electrolyte to be completed simultaneously in the primary electrolyte injection workshop, eliminating the need for inter-workshop transfer, significantly shortening the turnaround time, and significantly improving production efficiency.

[0028] In existing technologies, batteries are prone to impact and friction damage during transfer between different workshops. Furthermore, the batteries are already charged and activated before secondary electrolyte injection, posing a short-circuit safety hazard during transfer and the cutting of the aluminum-plastic film. This solution eliminates the need for inter-workshop battery transfer, reducing the risk of physical damage during transport. Simultaneously, it eliminates the need to cut the aluminum-plastic film, avoiding the short-circuit risk caused by exposure of the charged body, thus reducing two core risks from a process simplification perspective. Cutting the aluminum-plastic film exposes the battery interior to air for extended periods, making it susceptible to internal contamination from reactions with moisture in the air. In this solution, the sealing structure 100 stores the secondary electrolyte through a sealed cavity 110. The weak point 120 remains sealed until it cracks, preventing contact between the battery interior and the secondary electrolyte with air. Only when electrolyte injection is needed is the weak point 120 cracked by external force, allowing the electrolyte to flow rapidly into the battery body. With no exposure points throughout the process, air contamination of the battery interior is completely avoided, improving battery quality.

[0029] It should be noted that the aluminum-plastic film air bag 200 is a packaging component for the soft-pack battery 300. The aluminum-plastic film air bag 200 is located above the battery body and has a bag-like structure. The interior of the aluminum-plastic film air bag 200 has reserved space to accommodate the sealing head structure 100. The material of the aluminum-plastic film air bag 200 is the same as that of the sealing head structure 100, and a heat-sealing process can be used to achieve a sealed connection with the sealing head structure 100, forming an independent closed area to prevent external air or impurities from entering.

[0030] The accommodating cavity 110 is a cavity opened inside the end cap structure 100. The volume of the accommodating cavity 110 is set according to the secondary electrolyte filling requirements of the soft-pack battery 300, and is used to pre-store the electrolyte that needs to be filled twice. The cavity is sealed around by the sealing layer of the end cap structure 100 to ensure that there is no leakage of electrolyte when it is not filled.

[0031] The weak point 120 is a specific area on the end cap structure 100, located on the side of the accommodating cavity 110 near the battery body. Because this area is relatively thin, it is prone to cracking under external force, thus becoming a channel for electrolyte to flow into the battery body.

[0032] The soft-pack battery 300 body is the core energy storage component of the battery, including electrode plates, separator, primary electrolyte, etc., located below the aluminum-plastic film air bag 200. Its top is connected to the aluminum-plastic film air bag 200. When the weak part 120 of the end cap structure 100 cracks, the secondary electrolyte in the accommodating cavity 110 can flow into the body through the internal channel of the aluminum-plastic film air bag 200 to complete the secondary electrolyte injection.

[0033] In some embodiments, the head structure 100 includes a first segment 130, a second segment 140, and a third segment 150. One end of the second segment 140 is connected to the first segment 130, and the other end of the second segment 140 is connected to the third segment 150. The first segment 130 and the third segment 150 are disposed opposite to each other, and a weak portion 120 is disposed in the second segment 140. Specifically, the head structure 100 is a U-shaped structure.

[0034] In some embodiments, the minimum thickness of the weak portion 120 is 1 / 4 to 1 / 3 of the thickness of the end cap structure 100. This solution avoids the risk of leakage during the electrolyte storage stage caused by excessive thickness, and also avoids the difficulty of breaking the seal during the electrolyte injection stage caused by excessive thickness, ensuring zero electrolyte leakage in the non-injection state and controllable breaking during injection. This solution eliminates the need to cut the aluminum-plastic film, and the battery interior and secondary electrolyte are always isolated from air, completely solving the internal contamination problem caused by air and moisture in traditional processes, and ensuring battery quality stability.

[0035] Specifically, the weak part 120 is a groove on the inner sidewall of the end cap structure 100. Specifically, the groove includes a first groove wall and a second groove wall, the connection point of the first groove wall and the second groove wall is the minimum thickness of the weak part 120, and the first groove wall and the second groove wall are inclined.

[0036] Specifically, the weak section 120 has a V-shaped structure. The V-shaped weak section 120 is located on the inner wall of the second transverse section 140 of the end cap structure 100, forming a V-shaped concave shape. This weak section 120 consists of two symmetrically inclined groove walls and a bottom apex, with the apex being the area of ​​minimum thickness for the weak section 120. The V-shaped inclined groove walls can directionally transfer external compressive forces to the bottom apex, making the apex the weakest point in terms of structural strength, ensuring that only the apex region cracks when external forces are applied, thus preventing random fragmentation of the weak section 120.

[0037] In addition, the V-shaped inclined tank wall serves both a sealing and guiding function. During the non-filling stage, the V-shaped tank wall has no seams and, together with other areas of the end cap, forms a closed receiving cavity 110, preventing secondary electrolyte leakage. During the filling stage, after the apex cracks, the inclined tank wall forms a natural channel, guiding the electrolyte to flow rapidly along the tank wall to the soft-pack battery 300 body, preventing electrolyte stagnation within the receiving cavity 110.

[0038] In another embodiment, the weak portion 120 can also be an arc-shaped structure. The arc-shaped weak portion 120 also has an inner wall of the second transverse section 140 of the end cap structure 100, forming an arc-shaped recess. The lowest point of the recess is the area of ​​minimum thickness for the weak portion 120. The arc-shaped surface of the weak portion 120 disperses local pressure. Compared to a right-angle structure, the arc-shaped surface reduces stress concentration in the composite film during molding and storage, preventing unexpected cracking and ensuring long-term sealing of the accommodating cavity 110. Furthermore, since the lowest point of the arc-shaped recess has the minimum thickness, when external extrusion forces are applied, stress will naturally concentrate at the lowest point, causing this area to crack along an arc-shaped path. The resulting arc-shaped edge is smooth, preventing sharp film fragments from clogging the electrolyte channels.

[0039] In some embodiments, the weak portion 120 is disposed at the bottom of the head structure 100.

[0040] In some embodiments, the end cap structure 100 is disposed in the middle of the length direction of the aluminum-plastic film air bag 200, so that the middle of the aluminum-plastic film air bag 200 is subjected to balanced force, which can avoid cracking of the heat-sealed edge due to excessive stress on one side and ensure that the accommodating cavity 110 is sealed for a long time.

[0041] In some embodiments, two end cap structures 100 are provided, located on the front and back sides of the aluminum-plastic film air bag 200. This arrangement allows the electrolyte to flow into the pouch battery 300 body simultaneously from both sides, quickly covering the area of ​​the pouch battery 300 body. This avoids the problem of insufficient electrolyte at the edge electrodes of the pouch battery 300 body due to an excessively long diffusion path when using a single end cap, reducing the risk of capacity decay and shortened cycle life. Furthermore, the symmetrical layout makes the volume of the accommodating cavity 110 of the two end cap structures 100 controllable, allowing for flexible adjustment according to the electrolyte injection requirements of different battery specifications, ensuring consistent battery performance.

[0042] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the content of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. A sealing structure, applied to a soft-pack battery, and sealed within an aluminum-plastic film air bag, characterized in that, The end cap structure has a receiving cavity for containing electrolyte. The end cap structure has a weak part, the thickness of which is less than the thickness of the end cap structure. Under the action of external force, the weak part cracks, so that the electrolyte in the accommodating cavity flows into the body of the soft-pack battery through the aluminum-plastic film air bag.

2. The head structure according to claim 1, characterized in that, The head structure includes a first section, a second section, and a third section. One end of the second section is connected to the first section, and the other end of the second section is connected to the third section. The first section and the third section are arranged opposite to each other, and the weak part is located in the second section.

3. The head structure according to claim 1, characterized in that, The head structure is U-shaped.

4. The head structure according to claim 1, characterized in that, The minimum thickness of the weak part is 1 / 4 to 1 / 3 of the thickness of the head structure.

5. The head structure according to claim 1, characterized in that, The weak part is the groove on the inner sidewall of the head structure.

6. The head structure according to claim 5, characterized in that, The groove includes a first groove wall and a second groove wall. The connection point between the first groove wall and the second groove wall is the minimum thickness of the weak part, and the first groove wall and the second groove wall are inclined.

7. The head structure according to claim 1, characterized in that, The weak point is a V-shaped structure; or The weak part is a circular arc structure.

8. The head structure according to claim 1, characterized in that, The weak point is located at the bottom of the head structure.

9. The head structure according to claim 1, characterized in that, The end cap structure is located at the middle of the length of the aluminum-plastic film air bag.

10. The head structure according to claim 1, characterized in that, Two sealing structures are provided, and the two sealing structures are respectively provided on the front and back of the aluminum-plastic film air bag.

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