A safety sealing assembly for a cylindrical battery

Abstract

The application relates to the technical field of lithium batteries, in particular to a safe sealing combined structural member of a cylindrical battery, which comprises a shell, an inner isolation member and a sealing ring, a pole is riveted to the middle of one end of the shell, the inner isolation member is attached to the inner wall of the shell, the part of the inner isolation member close to the pole is filled between the flange and the straight section of the pole after being pressed by the pole, the part of the flange of the pole far from the straight section gradually inclines to the inner wall of the shell to form a non-flat riveting under-dog structure on the inner isolation member, meanwhile, the bending part of the inner isolation member matched between the flange and the straight section of the pole is previously formed with an R-angle structure to reduce the extrusion between the flange of the pole and the inner isolation member in the riveting process, the part of the sealing ring close to the pole is filled between the pole ring and the straight section of the pole after being pressed by the pole and is attached to the inner isolation member. The technical problem that electrolyte can penetrate into the sealing ring to cause performance hidden danger after the safe sealing combined structural member of the cylindrical battery of the lithium battery is riveted in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically a safety-sealed assembly structure for a cylindrical battery. Background Technology

[0002] After the safety sealing assembly of the cylindrical lithium battery is riveted and put into use, such as... Figure 1-2 As shown, the electrolyte will seep into the sealing ring through the gap 100 between the flange of the electrode and the inner separator. If the electrolyte seeps into the sealing ring area, some components of the DMC solution in the electrolyte will react with the sealing ring, causing the sealing ring to swell and the electrode to be squeezed outward, resulting in serious performance problems. Summary of the Invention

[0003] To address the technical problem in existing technologies where electrolyte seeps into the sealing ring after the safety sealing assembly of a cylindrical lithium battery is riveted, leading to potential performance issues, this application proposes a safety sealing assembly for a cylindrical battery that solves the aforementioned technical problem.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] This invention provides a safe and sealed assembly structure for a cylindrical battery, comprising: a housing, wherein a riveting hole is provided at the center of one end of the housing, and an electrode post is riveted to the riveting hole; an inner separator, wherein the inner separator is attached to the inner wall of the housing, and the portion of the inner separator near the electrode post is pressed by the electrode post and fills between the flange and the straight section of the electrode post, wherein the portion of the flange of the electrode post away from the straight section gradually slopes towards the inner wall of the housing to form a non-flat riveting under-clamp structure on the inner separator, and simultaneously, the inner separator has a pre-formed R-angle structure in conjunction with the bent portion between the flange and the straight section of the electrode post to reduce the compression between the flange of the electrode post and the inner separator during the riveting process; and a sealing ring, wherein the sealing ring is attached to the outer wall of the housing, and the portion of the sealing ring near the electrode post is pressed by the electrode post and fills between the ring and the straight section of the electrode post, and contacts and adheres to the inner separator.

[0006] Furthermore, assuming the thickness of the pole ring of the pole post is B, the flange before riveting is thinned so that the vertical distance A from the inner end face of the pole post away from the pole ring to the low plane where the inner spacer fits against the inner wall of the housing after riveting is ≤0.8B, in order to reduce the flange stress during riveting. At the same time, the groove depth C between the flange and the inner end face of the pole post before riveting is deepened so that C≥0.5A, in order to reduce the flange stress during riveting.

[0007] Furthermore, the safety sealing assembly of the cylindrical battery is riveted to the terminal post by a pre-pressing fixture. The pre-pressing fixture includes a central rivet rod and a pre-pressing sleeve surrounding the central rivet rod. During riveting, the pre-pressing sleeve first pre-presses the portion of the inner separator away from the terminal post, and then the central rivet rod punches the terminal post to complete the riveting.

[0008] Furthermore, the pre-compression fixture also includes an upper mold, the central rivet is directly fixedly connected to the upper mold, and a collapsible space is left between the pre-compression sleeve and the bottom end connection surface of the upper mold and is connected to the upper mold by a spring.

[0009] Furthermore, it also includes a lower riveting fixture that receives the housing during the riveting stage. The pre-compression sleeve of the pre-compression fixture presses down on the inner spacer while simultaneously pressing down on the lower riveting fixture to fix the lower riveting fixture in place.

[0010] Furthermore, before riveting, the inner side of the flange of the pole post and the contact area with the central rivet rod form a chamfer. The contact area between the central rivet rod and the pole post is the variable diameter section of the central rivet rod. The inclination angle of the chamfer of the pole post is adapted to the maximum inclination angle of the variable diameter section of the central rivet rod, so that the chamfer of the pole post after being deformed by pressure in the first moment tends to be parallel to the variable diameter section of the central rivet rod. At the same time, the variable diameter section of the central rivet rod is formed as a concave contoured arc section.

[0011] Furthermore, the inclination angle of the chamfer of the pole before riveting is slightly lower than the maximum inclination angle of the variable diameter section of the center rivet before it is concave and contoured.

[0012] Furthermore, after polishing the contact area between the central rivet and the pole post, a DLC coating is added to increase the local hardness of the central rivet.

[0013] Based on the above technical solution, the technical effects that this invention can achieve are as follows:

[0014] Electrolyte penetration into the sealing ring area causes the sealing ring to swell, pushing the electrode post outwards and creating serious performance issues. To prevent electrolyte penetration, it is necessary to increase the riveting strength by adjusting the riveting parameters to increase the compression of the inner separator. However, simply increasing the riveting strength alone can cause the side of the inner separator away from the electrode post to warp, leading to electrode ring deformation and material buildup on the inner side of the electrode post flange. Therefore, to increase the riveting strength, the structure of the electrode post and the inner separator itself needs to be adjusted. In the safety sealing assembly structure of the cylindrical battery of this invention, the portion of the electrode post flange away from the straight section gradually slopes towards the inner wall of the casing to form a non-flat riveting under-clamp structure on the inner separator. In this way, the flange stress on the side of the inner separator near the electrode post is no longer unilaterally outwards (in this case, the inner separator is closer to the electrode post). If one side of the terminal post is subjected to excessive force, the side away from the terminal post will detach from the inner wall of the casing and warp. Instead, the stress is distributed to both the inner and outer sides (in this case, the two sides of the inner separator share the warping stress). This can prevent the inner separator from warping after increasing the riveting strength. The buckling structure can also block the electrolyte penetration path, preventing the electrolyte from penetrating to the sealing ring. At the same time, the inner separator is pre-formed with an R-angle structure in the bend between the flange and the straight section of the terminal post, making the transition smoother. This reduces the squeezing between the flange of the terminal post and the inner separator during the riveting process after increasing the riveting strength, thereby avoiding the deformation of the terminal ring and the problem of material accumulation on the inner side of the flange of the terminal post. This allows the safety sealing assembly structure of the cylindrical battery to withstand greater riveting strength to prevent electrolyte penetration.

[0015] The safety sealing assembly structure of the cylindrical battery of the present invention thins the flange before riveting and deepens the groove between the flange and the inner end face of the electrode before riveting to reduce the flange stress during riveting. By modifying the electrode design, the deformation of the electrode ring during the flange process is reduced, so that the electrode can withstand greater riveting strength to avoid electrolyte penetration.

[0016] The safety sealing assembly structure of the cylindrical battery of the present invention uses a pre-pressing tooling to complete the riveting of the electrode post. During riveting, the pre-pressing sleeve first pre-presses the part of the inner separator away from the electrode post, and then the central rivet rod punches the electrode post to complete the riveting. Specifically, a tooling and process is proposed that first presses the side of the inner separator that will lift up, and then riveting is performed, thereby increasing the riveting strength without causing the inner separator to lift up and avoiding electrolyte penetration.

[0017] The safety sealing assembly structure of the cylindrical battery of the present invention involves a pre-compression tooling. A collapsible space is left between the pre-compression sleeve and the bottom end connection surface of the upper mold and the pre-compression sleeve is connected to the upper mold by a spring. During the pressing down of the upper mold, the spring provides a gradually increasing pressing force on the inner isolator to prevent the inner isolator from warping or deforming. At the same time, the pre-compression sleeve fixes the lower riveting tooling, which can also make the riveting process more stable and controllable.

[0018] The safety sealing assembly structure of the cylindrical battery of the present invention adjusts the inner side of the flange opening before riveting the terminal post from the original rounded corner to a chamfer that matches the maximum inclination angle of the variable diameter section of the central rivet. This makes the chamfer of the terminal post after pressure deformation more parallel to the variable diameter section of the central rivet, reducing the sharp point contact between the rivet and the central rivet during the pressing process, thereby reducing the risk of scratching between the two and ensuring that the flange of the terminal post after riveting is free from abnormal particle size. This allows the terminal post to withstand greater riveting strength and avoids electrolyte penetration. Furthermore, the variable diameter section of the central rivet is formed into a concave, contoured arc section, making the force application process of the central rivet pressing down on the terminal post smoother, thereby further reducing the risk of scratching and ensuring that the flange of the terminal post after riveting is free from abnormal particle size. This allows the terminal post to withstand greater riveting strength and avoids electrolyte penetration.

[0019] The safety sealing assembly structure of the cylindrical battery of the present invention adds a DLC coating to the contact area between the central rivet and the terminal post after polishing, which improves the hardness of the central rivet, reduces roughness, makes the transition of the terminal post flange smoother, reduces the situation of aluminum wire accumulation in the terminal post, thereby reducing the risk of abnormal rivet particle size, allowing the terminal post to withstand greater riveting strength, and avoiding electrolyte penetration. Attached Figure Description

[0020] Figure 1 A partial schematic diagram of the riveted assembly of a safety-sealed cylindrical battery in the prior art.

[0021] Figure 2 A partial schematic diagram of the safety sealing assembly structure of a cylindrical battery in the prior art before riveting is completed;

[0022] Figure 3 This is a partial schematic diagram of the safety sealing assembly structure of the cylindrical battery of the present invention after riveting is completed;

[0023] Figure 4 This is a partial schematic diagram of the safety sealing assembly structure of the cylindrical battery of the present invention before riveting is completed;

[0024] Figure 5 This is a schematic diagram of the pre-compression fixture for the safety sealing assembly structure of the cylindrical battery of the present invention;

[0025] Figure 6This is a partially enlarged schematic diagram of the central rivet of the pre-compression tooling for the safety sealing assembly structure of the cylindrical battery of the present invention.

[0026] in:

[0027] 100-gap;

[0028] 1-Shell, 11-Pole post, 111-Flanged edge, 1111-Beveled chamfer, 112-Straight section, 113-Pole ring; 2-Inner separator, 21-Lower buckle structure, 22-R-angle structure; 3-Sealing ring; 4-Pre-compression fixture, 41-Center rivet, 411-Variable diameter section, 42-Pre-compression sleeve, 43-Upper mold.

[0029] 5-Riveting fixture. Detailed Implementation

[0030] 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. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0031] like Figure 3-6 As shown, this invention provides a safe and sealed assembly structure for a cylindrical battery, including a housing 1, an inner separator 2, and a sealing ring 3. A riveting hole is provided at the center of one end of the housing 1, and a terminal post 11 is riveted to the riveting hole. The inner separator 2 is fitted to the inner wall of the housing 1. The portion of the inner separator 2 near the terminal post 11 is pressed by the terminal post 11 and fills the space between the flange 111 and the straight section 112 of the terminal post 11. The portion of the flange 111 of the terminal post 11 away from the straight section 112 gradually slopes towards the inner wall of the housing 1 to form a non-flat riveted snap-fit ​​structure 21 on the inner separator 2. Simultaneously, the bent portion of the inner separator 2 between the flange 111 and the straight section 112 of the terminal post 11 is pre-formed with an R-angle structure 22 (for comparison). Figure 1 and Figure 3 To reduce the squeezing between the flange 111 of the pole post 11 and the inner spacer 2 during the riveting process, the sealing ring 3 is attached to the outer wall of the housing 1. The part of the sealing ring 3 near the pole post 11 is filled between the pole ring 113 and the straight section 112 of the pole post 11 after being pressed by the pole post 11, and is in contact with and attached to the inner spacer 2.

[0032] In a specific embodiment of the present invention, the thickness of the electrode ring 113 of the electrode post 11 is set to B. The flange 111 before riveting is thinned so that the vertical distance A from the inner end face of the electrode post 11 away from the electrode ring 113 (i.e., the end face of the electrode post 11 inside the finished battery) to the low plane of the inner separator 2 that is attached to the inner wall of the housing 1 is ≤ 0.8B. A=0.8B is the optimal value. However, considering that there will be tolerances in the actual product, when A cannot be exactly 0.8B, a value slightly less than 0.8B is taken to reduce the stress of the flange 111 during riveting. At the same time, the groove depth C between the flange 111 and the inner end face of the electrode post 11 before riveting is increased so that C≥0.5A. C=0.5A is the optimal value. However, considering that there will be tolerances in the actual product, when C cannot be exactly 0.5A, a value slightly greater than 0.5A is taken to reduce the stress of the flange 111 during riveting.

[0033] In a specific embodiment of the present invention, the safety sealing assembly of the cylindrical battery is riveted to the terminal post 11 by a pre-pressing fixture 4. The pre-pressing fixture 4 includes a central riveting rod 41 and a pre-pressing sleeve 42 surrounding the central riveting rod 41. During riveting, the pre-pressing sleeve 42 first pre-presses the part of the inner separator 2 away from the terminal post 11, and then the central riveting rod 41 punches the terminal post 11 to complete the riveting.

[0034] In a specific embodiment of the present invention, the pre-compression fixture 4 further includes an upper mold 43, a central rivet 41 is directly fixedly connected to the upper mold 43, and a collapsing space is left between the pre-compression sleeve 42 and the bottom end connection surface of the upper mold 43 and is connected to the upper mold 43 by a spring.

[0035] Furthermore, it also includes a lower riveting fixture 5 that receives the housing 1 during the riveting stage. The pre-compression sleeve 42 of the pre-compression fixture 4 presses down the inner isolation piece 2 and simultaneously presses down the lower riveting fixture 5 to fix the lower riveting fixture 5.

[0036] A collapsible space is left between the pre-compression sleeve 42 and the bottom end connection surface of the upper mold 43 and it is connected to the upper mold 43 by a spring. During the pressing process of the upper mold 43, the spring provides a gradually increasing pressing force on the inner isolation part 2 to prevent the inner isolation part 2 from warping or deforming. At the same time, the pre-compression sleeve 42 fixes the lower riveting fixture 5, which can also make the riveting process more stable and controllable.

[0037] In a specific embodiment of the present invention, the inner side of the flange 111 of the pole post 11 before riveting and the contact area with the central rivet 41 form a chamfer 1111. The contact area between the central rivet 41 and the pole post 11 is the variable diameter section 411 of the central rivet 41. The inclination angle of the chamfer 1111 of the pole post 11 is adapted to the maximum inclination angle of the variable diameter section 411 of the central rivet 41, so that the chamfer 1111 of the pole post 11 after being deformed by pressure in the first time tends to be parallel to the variable diameter section 411 of the central rivet 41. At the same time, the variable diameter section 411 of the central rivet 41 is formed as a concave contoured arc section.

[0038] In one specific embodiment of the present invention, the inclination angle of the chamfer 1111 of the pole post 11 before riveting is slightly lower than the maximum inclination angle of the variable diameter section 411 of the center rivet 41 before it is concave and contoured.

[0039] In one specific embodiment of the present invention, a DLC coating is added to the contact area between the central rivet 41 and the pole post 11 after polishing to increase the local hardness of the central rivet 41.

[0040] It should be understood that the specific embodiments described above are for illustrative purposes only and are not intended to limit the scope of the invention. Obvious variations or modifications derived from the spirit of the invention are still within the protection scope of the invention.

Claims

1. A safety-sealed assembly structure for a cylindrical battery, characterized in that, include: The housing (1) has a rivet hole at the middle of one end, and a pole post (11) is riveted to the rivet hole. The inner isolator (2) is attached to the inner wall of the housing (1). The part of the inner isolator (2) near the pole post (11) is pressed by the pole post (11) and filled between the flange (111) and the straight section (112) of the pole post (11). The part of the flange (111) of the pole post (11) away from the straight section (112) gradually tilts towards the inner wall of the housing (1) to form a non-flat riveting bottom buckle structure (21) on the inner isolator (2). At the same time, the inner isolator (2) has a pre-formed R-angle structure (22) in the bent part between the flange (111) and the straight section (112) of the pole post (11) to reduce the squeezing between the flange (111) of the pole post (11) and the inner isolator (2) during the riveting process. A sealing ring (3) is attached to the outer wall of the housing (1). The part of the sealing ring (3) near the pole post (11) is pressed by the pole post (11) and filled between the pole ring (113) and the straight section (112) of the pole post (11), and is in contact with the inner isolation member (2). Let the thickness of the pole ring (113) of the pole post (11) be B. Before riveting, the flange (111) is thinned so that the vertical distance A from the inner end face of the pole post (11) away from the pole ring (113) to the low plane where the inner isolator (2) is attached to the inner wall of the shell (1) is ≤0.8B, so as to reduce the stress of the flange (111) during riveting. At the same time, the groove depth C between the flange (111) and the inner end face of the pole post (11) before riveting is increased so that C≥0.5A, so as to reduce the stress of the flange (111) during riveting. The safety sealing assembly of the cylindrical battery is riveted to the pole (11) by a pre-pressing fixture (4). The pre-pressing fixture (4) includes a central rivet (41) and a pre-pressing sleeve (42) surrounding the central rivet (41). During riveting, the pre-pressing sleeve (42) first pre-presses the part of the inner separator (2) away from the pole (11), and then the central rivet (41) punches the pole (11) to complete the riveting.

2. The safety sealing assembly structure for a cylindrical battery according to claim 1, characterized in that, The pre-compression fixture (4) also includes an upper mold (43), the central rivet (41) is directly fixedly connected to the upper mold (43), and the pre-compression sleeve (42) and the bottom end connection surface of the upper mold (43) have a collapsing space and are connected to the upper mold (43) by a spring.

3. The safety sealing assembly structure for a cylindrical battery according to claim 2, characterized in that, It also includes a lower riveting fixture (5) that receives the housing (1) during the riveting stage. The pre-compression sleeve (42) of the pre-compression fixture (4) presses down the inner isolation member (2) and simultaneously presses down the lower riveting fixture (5) to fix the lower riveting fixture (5).

4. The safety sealing assembly structure for a cylindrical battery according to claim 1, characterized in that, Before riveting, the inner side of the flange (111) of the pole post (11) and the contact area with the center rivet (41) form a chamfer (1111). The contact area between the center rivet (41) and the pole post (11) is the variable diameter section (411) of the center rivet (41). The inclination angle of the chamfer (1111) of the pole post (11) is adapted to the maximum inclination angle of the variable diameter section (411) of the center rivet (41), so that the chamfer (1111) of the pole post (11) after being deformed by pressure in the first time tends to be parallel to the variable diameter section (411) of the center rivet (41). At the same time, the variable diameter section (411) of the center rivet (41) is formed as a concave contoured arc section.

5. The safety sealing assembly structure for a cylindrical battery according to claim 4, characterized in that, Before riveting, the inclination angle of the chamfer (1111) of the pole post (11) is slightly lower than the maximum inclination angle of the variable diameter section (411) of the center rivet (41) before it is concave and contoured.

6. The safety sealing assembly structure for a cylindrical battery according to claim 4, characterized in that, After polishing, a DLC coating is added to the contact area between the central rivet (41) and the pole post (11) to increase the local hardness of the central rivet (41).

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