Battery cover plate assembly assembling process and battery cover plate assembly

Abstract

The invention relates to the field of batteries, in particular to a battery cover plate assembly assembling process and a battery cover plate assembly. The assembly process comprises the following steps: S1, providing a sealing ring, and a cover plate main body and a pole which are made of metal; the cover plate main body is provided with a barrel with an annular body on the inner peripheral wall; s2, placing the pole and the sealing ring in the cylinder; the horizontal sealing part of the sealing ring is clamped between the top end surface of the annular body and the pole, and the pole is not in contact with the cylinder; s3, compressing the horizontal sealing part, performing spin riveting on the barrel, and bending the upper end part of the barrel inwards to form a turned edge which is blocked above the edge area of the pole at an interval; and S4, compressing the horizontal sealing part, and performing injection molding and rubber coating to form an injection molding part which connects the cover plate main body, the pole and the sealing ring into an integral structure, completely wraps the turned-over edge and fills a gap between the cylinder and the pole. According to the invention, under the condition of ensuring good sealing performance of the battery cover plate assembly, the problem that the conductivity of the battery cell is influenced by hidden cracks of the pole and metal residues can be solved.

Description

Technical Field

[0001] This invention relates to the field of batteries, and more specifically to a battery cover assembly process and a battery cover assembly. Background Technology

[0002] In the field of lithium-ion battery manufacturing, the battery cover assembly, as a key component for the safe sealing and electrical connection of the battery cell, typically consists of a cover body, a metal cylinder penetrating the cover body, terminals passing through the cylinder, and a sealing and insulating part filling the space between the cylinder and the terminals. To ensure that the battery cell can withstand expansion forces of up to 2000N during charging and discharging, traditional processes require riveting the upper end of the cylinder: by rotating the riveting head at high speed, the upper edge of the cylinder is plastically deformed inward to form a flanged structure that presses against the sealing and insulating part, thereby achieving mechanical fixation and enhanced sealing.

[0003] However, the riveting process in this traditional assembly process has two major problems: Firstly, there is a risk of microcracks in the terminal posts: the radial extrusion force and high-frequency vibration applied during the riveting process can easily cause micro-cracks inside the metal terminal posts. These cracks are inconspicuous and difficult to detect with conventional testing. After long-term service, they may lead to terminal post breakage, causing battery connection failure or even thermal runaway.

[0004] Secondly, metal contamination residue: The friction between the high-speed riveting machine and the cylinder generates a large amount of metal dust, debris, and filamentous residue, such as... Figure 7 As shown.

[0005] The industry has attempted to add an air-blowing process, but due to various reasons, such as debris being trapped in the overlapping gaps between the flanges and the sealing insulation, electrostatic adsorption causing micron-sized dust to adhere to the surface of the insulation material, and geometric dead angles in the bending area of ​​the cylinder hindering effective airflow penetration, the air-blowing process cannot completely remove metal residues. These metal residues reduce the contact impedance between the electrode and the external circuitry, inducing micro-short circuits or localized arc discharges, accelerating electrochemical corrosion, and ultimately leading to battery capacity decay, increased self-discharge rate, and safety hazards.

[0006] Therefore, we must continue to address the aforementioned technical problems caused by the traditional battery cover assembly process. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a battery cover assembly process that can solve the problems of terminal cracks and metal residue affecting the conductivity of the battery cell in battery cover assemblies assembled by traditional assembly processes, while ensuring good sealing performance of the battery cover assembly.

[0008] To solve the above-mentioned technical problems, the technical solution of the present invention is: a battery cover assembly process, comprising: Step S1, providing a cover plate body, an electrode post, and a sealing ring; wherein, the cover plate body and the electrode post are both made of metal, the cover plate body is provided with a cylindrical body that penetrates through it and protrudes from its top end, and the inner peripheral wall of the cylindrical body is provided with an annular body; Step S2: Place the pole and the sealing ring inside the cylinder; wherein, the horizontal sealing part of the sealing ring is sandwiched between the top surface of the annular body and the pole, and there is no contact between the pole and the cylinder; Step S3: Apply pressure to the pole post to compress the horizontal sealing part, and rivet the cylinder body to make the upper end of the cylinder body bend inward to form a flange that blocks the edge area of ​​the pole post with a gap. Step S4: Apply pressure to the pole to compress the horizontal sealing part, and perform injection molding to form an injection-molded part that connects the cover plate body, the pole and the sealing ring into an integral structure, completely wraps the flange, and fills the gap between the cylinder and the pole.

[0009] Furthermore, the sealing ring also has a vertical sealing portion that connects to the horizontal sealing portion; Step S2 includes: Step S21: The vertical sealing part of the sealing ring is fitted onto the vertical mating part of the pole post, and the two are interference fit. Step S21: Place the pole and the sealing ring into the cylinder from the top of the cylinder; wherein the vertical sealing part is inserted into the annular body.

[0010] Furthermore, the holes in the annular body and the holes in the vertical sealing part are both prismatic holes, and the outer peripheral walls of the vertical sealing part and the vertical mating part are respectively prismatic in shape to match the corresponding prismatic holes.

[0011] Furthermore, the cross-section of the prism hole is rhomboid, and the adjacent sidewalls of the prism hole are transitioned with rounded corners.

[0012] Furthermore, the portion of the pole that presses against the horizontal sealing part is a crimping part, and the cross-section of the crimping part is a polygon with a number of sides of not less than ten; The hole on the cross-section of the part of the cylinder that surrounds the pressing part with a gap and faces the outer peripheral wall of the pressing part is a polygonal hole with the same number of sides as the polygon. In step S2, during the process of placing the pole and the sealing ring into the cylinder, the pressing part and the cylinder are positioned so that the corresponding sides of the polygon and the polygonal hole are parallel to each other.

[0013] Furthermore, the portion of the cylinder used for flanging is made thicker.

[0014] Furthermore, step S3 includes: In step S31, the high-speed riveting machine lowers the intermediate push rod and presses it against the top of the pole post, compressing the horizontal sealing part; Step S32: The double riveting wheel rotates to roll the upper end of the cylinder inward to form an inner trumpet shape; Step S33: The flange is flattened by a second rolling process.

[0015] Furthermore, step S4 includes: Step S41: Place the cover plate body into the injection mold with the top facing upwards; Step S42: The injection mold closes, the upper mold ejector pin presses down against the top of the pole post, and the horizontal sealing part is compressed; Step S43: Inject injection molding compound into the creepage gap and hold pressure to cure and form the injection molded part.

[0016] Furthermore, the material of the injection-molded part is PVS.

[0017] The present invention also relates to a battery cover assembly, comprising: The main body of the cover plate is made of metal and has a cylindrical body that extends through it and protrudes from its top. The inner circumferential wall of the cylindrical body is provided with an annular body. A sealing ring having a horizontal sealing portion disposed on the annular body; A metal pole extends into the cylinder without contacting the cylinder, and together with the top surface of the annular body, clamps the horizontal sealing part. The upper end of the cylinder has a flange that blocks the edge area of ​​the pole with a gap. The injection molding part completely covers the flange and fills the gap between the cylinder and the pole.

[0018] After adopting the above technical solution, in the assembly process of the present invention, the vertical pressure applied to the pole during the compression of the horizontal sealing part is much less damaging to the pole than the radial extrusion force applied to the pole during the riveting process of the traditional assembly process, and the riveting will not cause microcracks in the pole. In addition, whether it is the riveting process or the injection molding process, by pressing down the pole to compress the horizontal sealing part, a gap exists between the flange and the upper part of the pole edge. Therefore, even if metal dust, debris and filamentous residues are generated in the riveting process, these metal residues can easily detach from the pole and the barrel. Even if they do not detach, the injection part generated by the injection molding completely wraps the flange and fills the gap, and the metal residues will not have any impact on the conductivity of the battery cell. Therefore, this embodiment effectively solves the problems of microcracks in the terminal posts and metal residue affecting the conductivity of the battery cells in battery cover assemblies assembled by traditional assembly processes; furthermore, by flanging and intermittently blocking the edge area of ​​the terminal posts and then injection molding and overmolding, the assembled battery cover assembly has better sealing performance and can withstand greater expansion thrust generated by the battery cells during charging and discharging after being applied to the battery. Attached Figure Description

[0019] Figure 1 This is a flowchart of the battery cover assembly process of the present invention; Figure 2 This is an exploded view of the battery cover assembly of the present invention; Figure 3 This is a top view of the battery cover assembly of the present invention; Figure 4 for Figure 3 AA section view; Figure 5 This is a cross-sectional view of the vertical mating part of the terminal post, the vertical sealing part of the sealing ring, and the mating position of the cylinder in the battery cover assembly of the present invention. Figure 6 This is a cross-sectional view of the mating position between the crimping part of the pole post and the cylinder of the present invention; Figure 7 Images of several products carrying metal scraps assembled using a traditional battery cover assembly process. In the diagram, 1 is the cover plate body; 2 is the pole; 21 is the vertical mating part; 22 is the pressing part; 3 is the sealing ring; 31 is the horizontal part; 32 is the vertical sealing part; 4 is the cylinder; 41 is the annular body; 42 is the flange; and 5 is the injection molding part. Detailed Implementation

[0020] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0021] Example 1: As Figures 1 to 6As shown, a battery cover assembly assembly process includes: Step S1, providing a cover plate body 1, an pole post 2 and a sealing ring 3; wherein, the cover plate body 1 and the pole post 2 are both made of metal, the cover plate body 1 is provided with a cylindrical body 4 that penetrates through it and protrudes from its top end, and the inner peripheral wall of the cylindrical body 4 is provided with an annular body 41. Step S2: Place the pole post 2 and the sealing ring 3 inside the cylinder 4; wherein, the horizontal sealing part 31 of the sealing ring 3 is sandwiched between the top surface of the annular body 41 and the pole post 2, and there is no contact between the pole post 2 and the cylinder 4. Step S3: Apply pressure to the pole post 2 to compress the horizontal sealing part 31, and rivet the cylinder 4 so that the upper end of the cylinder 4 is bent inward 42 to form a flange 42 that blocks the edge area of ​​the pole post 2 with a gap. Step S4: Apply pressure to the pole post 2 to compress the horizontal sealing part 31, and perform injection molding to form the injection molded part 5, which connects the cover plate body 1, pole post 2 and sealing ring 3 into an integral structure, completely wraps the flange 42, and fills the gap between the cylinder body 4 and the pole post 2.

[0022] Specifically, in the assembly process of this embodiment, the vertical pressure (approximately 30 kgf) applied to the pole post 2 during the compression of the horizontal sealing part 31 is much less damaging to the pole post 2 compared to the radial extrusion force applied to the pole post 2 during the riveting process of the traditional assembly process (approximately 200 kgf when riveting a single pole post 2 using a 100 mm diameter cylinder). Therefore, the riveting process in this embodiment will not cause microcracks in the pole post 2. In addition, whether it is the riveting process or the injection molding process, by pressing down the pole post 2 to compress the horizontal sealing part 31, a gap exists between the flange 42 and the upper part of the edge of the pole post 2. Therefore, even if metal dust, debris and filamentous residues are generated during the riveting process, these metal residues can easily detach from the pole post 2 and the cylinder 4. Even if they do not detach, the injection part 5 generated by the injection molding process completely wraps the flange 42 and fills the gap, so the metal residues will not have any impact on the conductivity of the battery cell. Therefore, this embodiment effectively solves the problems of hidden cracks in the terminal post 2 and metal residue affecting the conductivity of the battery cell in battery cover assembly assembled by traditional assembly processes; furthermore, the flange 42 is positioned above the edge area of ​​the terminal post 2 with a gap and is injection molded and coated, resulting in a battery cover assembly with better sealing performance. After being applied to the battery, it can withstand the greater expansion thrust generated by the battery cell during charging and discharging.

[0023] In this embodiment, there are two cylindrical bodies 4 and two pole posts 2, one for positive and one for negative. The cover plate body, the cylindrical body 4, and the annular body 41 can be, but are not limited to, an integral structure formed by punching, flanging, and upsetting, and the material can be aluminum alloy, specifically AL-3003 H14. The positive pole post is made of aluminum alloy, specifically AL 1060 H18, and the negative pole post is made of copper-aluminum composite material, specifically AL1060H18+CU T2. The sealing ring 3 is made of fluororubber, specifically Viton GF-200S, 3M-E21900, or Daikin G902.

[0024] In this embodiment, as Figure 2 , Figure 4 and Figure 5 As shown, preferably, the sealing ring 3 also has a vertical sealing portion 32 connecting the horizontal sealing portion 31; step S2 may include: Step S21: The vertical sealing part 32 of the sealing ring 3 is fitted onto the vertical mating part 21 of the pole post 2, and the two are interference fit. Step S21: Place the pole post 2 along with the sealing ring 3 into the cylinder 4 from the top of the cylinder 4; wherein, the vertical sealing part 32 is installed into the annular body 41.

[0025] Specifically, considering that there is no contact between the pole post 2 and the cylinder 4, a vertical sealing part 32 is provided between the inner circumferential wall of the annular body 41 and the vertical mating part 21 of the pole post 2. This can effectively position the pole post 2, ensure the uniformity of the gap between the pole post 2 and the cylinder 4 in the circumferential direction, ensure the uniformity of the thickness of the portion of the injection molded part 5 filling the gap between the pole post 2 and the cylinder 4, avoid local thinning, improve strength, insulation performance and sealing performance, and prevent leakage during subsequent use.

[0026] More preferably, such as Figure 2 and Figure 5 As shown, the holes in the annular body 41 and the vertical sealing part 32 are both prismatic holes, and the outer peripheral walls of the vertical sealing part 32 and the vertical mating part 21 are respectively prismatic in shape to match the corresponding prismatic holes.

[0027] Specifically, the vertical mating part 21 of the electrode post 2 and the vertical sealing part 32 of the sealing ring 3, as well as the vertical sealing part 32 of the sealing ring 3 and the annular body 41, both employ a prism structure and prism hole fit. This serves two purposes: firstly, to prevent torsion and rotation, stabilizing the electrode post 2 structure and preventing it from rotating (rotation of the electrode post 2 would damage the internal seal of the cover, and inverting the cell would increase electrolyte leakage, short circuit risk, and allow air / water to enter the cell, potentially leading to spontaneous combustion). Secondly, this anti-rotation mechanism ensures a stable position during the assembly process, riveting / injection molding, and uniform creepage clearance between the upper electrode arm and the inner cavity of the top cover. This prevents relative rotation between the vertical mating part 21 and the vertical sealing part 32 of the electrode post 2, and between the vertical sealing part 32 and the annular body 41, during the assembly of the battery cover assembly and subsequent use, thereby ensuring the quality of the produced battery cover assembly.

[0028] exist Figure 2 and Figure 5 In the example shown, the cross-section of the prism hole is rhomboid, meaning the prism hole is a rhomboid hole. Furthermore, the adjacent sidewalls of the prism hole are rounded. The design of the rhomboid hole provides better mechanical properties, enhances the overall stability of the material, and makes it less prone to tilting or deformation under stress. The size and spacing of the rhomboid holes are optimized to ensure the uniformity and stability of the hole walls. This uniform distribution helps to distribute forces evenly across the entire rhomboid hole wall under stress, thus preventing localized tilting or deformation.

[0029] In this embodiment, as Figure 2 and Figure 4 As shown, preferably, the portion of the horizontal sealing part 31 of the pole post 2 is a crimping part 22, and the cross-section of the crimping part 22 is a polygon with a number of sides not less than ten. The hole on the cross-section of the part of the cylinder 4 that surrounds the crimping part 22 with a gap and faces the outer peripheral wall of the crimping part 22 is a polygonal hole with the same number of sides as the polygon. In step S2, during the process of placing the pole post 2 and the sealing ring 3 into the cylinder 4, the positioning pressing part 22 and the cylinder 4 are positioned so that the corresponding sides of the polygon and the polygon hole are parallel to each other.

[0030] The polygon is preferably a regular decagon or a regular dodecagon.

[0031] This design ensures that the portion of the injection molding part 5 located between the outer peripheral wall of the pressing part 22 and the inner peripheral wall of the cylinder 4 also provides anti-torsion protection, thereby increasing the strength of the produced battery cover assembly. Furthermore, having at least ten sides on each polygon ensures that even slight misalignment between the polygons and their holes during assembly will not cause excessive thinning of the portion of the injection molding part 5 located between the outer peripheral wall of the pressing part 22 and the inner peripheral wall of the cylinder 4, thus improving fault tolerance.

[0032] In this embodiment, as Figure 4 As shown, preferably, the portion of the cylinder 4 used for the flange 42 is thickened.

[0033] This design reduces the riveting force. Furthermore, the thickness reduction process can create stepped surfaces on the inner and / or outer peripheral walls of the cylinder 4, improving the bonding strength between the cylinder 4 and the injection-molded part 5.

[0034] In this embodiment, step S3 may include: In step S31, the high-speed riveting machine lowers the intermediate push rod and presses it against the top of the pole post 2, compressing the horizontal sealing part 31, preferably by 30%-40%; Step S32: The double riveting wheel rotates to roll the upper end flange 42 of the cylinder 4 inward to form an inner trumpet shape, preferably with a bending angle of 135°. Step S33: The second rolling process flattens the flange 42, making the bending angle 90°.

[0035] In this step, after the riveting mechanism / pressure rod rises, the horizontal sealing part 31 of the sealing ring 3 springs back, and the top surface of the pole post 3 can release the inner surface of the flange 42, or a gap can be left between the inner surfaces of the flange 42.

[0036] In this embodiment, step S4 may include: Step S41: Place the cover plate body 1 into the injection mold with the top facing upwards; In step S42, the injection mold closes, the upper mold ejector pin presses down against the top of the pole post 2, and the horizontal sealing part 31 is compressed, preferably by 30%-40%; Step S43: Inject injection molding compound from the creepage gap, hold pressure and cure to form injection part 5, preferably hold pressure for 5s.

[0037] In this embodiment, the material of the injection-molded part 5 is preferably PVS. This provides better high-temperature resistance and insulation properties, which is beneficial for long-term use.

[0038] In this embodiment, after step S4, the following steps are also included: Step S5, lower plastic assembly welding, specifically: Invert the cover plate body 1 with the back facing up, use the suction nozzle to pick up the material and CCD vision to locate the length and width of the top cover piece, insert the top cover, and press down the ultrasonic welding head corresponding to the plastic hot melt point to ensure contact surface fit. Apply high-frequency vibration (amplitude usually 20-60μm) to the welding head for 0.1-1 seconds, maintain pressure after vibration stops (about 0.5-2 seconds), the molten layer solidifies and forms, the welding head is withdrawn, and the welding is completed.

[0039] Example 2: Figures 2 to 6 As shown, a battery cover assembly includes: The main body 1 of the cover plate is made of metal and has a cylindrical body 4 that runs through it and protrudes from its top. The inner circumferential wall of the cylindrical body 4 is provided with an annular body 41. The sealing ring 3 has a horizontal sealing portion 31 placed on the annular body 41; The metal pole post 2 extends into the cylinder 4 without contacting the cylinder 4, and together with the top surface of the annular body 41, clamps the horizontal sealing part 31. The upper end of the cylinder 4 has a flange 42 that blocks the edge area of ​​the pole post 2 with a gap. The injection molding part 5 completely wraps the flange 42 and fills the gap between the cylinder 4 and the pole 2.

[0040] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A battery cover assembly assembly process, characterized in that, include: Step S1, provide a cover plate body (1), an pole post (2) and a sealing ring (3); wherein, the cover plate body (1) and the pole post (2) are both made of metal, the cover plate body (1) is provided with a cylindrical body (4) that penetrates through it and protrudes from its top end, and the inner peripheral wall of the cylindrical body (4) is provided with an annular body (41). Step S2, place the pole post (2) and the sealing ring (3) inside the cylinder (4); wherein, the horizontal sealing part (31) of the sealing ring (3) is sandwiched between the top surface of the annular body (41) and the pole post (2), and there is no contact between the pole post (2) and the cylinder (4); Step S3: Apply pressure to the pole post (2) to compress the horizontal sealing part (31), and rivet the cylinder (4) so ​​that the upper end of the cylinder (4) is bent inward (42) to form a flange (42) that blocks the edge area of ​​the pole post (2) with a gap. Step S4: Apply pressure to the pole (2) to compress the horizontal sealing part (31) and inject molding to form an injection molded part (5) that connects the cover plate body (1), the pole (2) and the sealing ring (3) into an integral structure, completely wraps the flange (42), and fills the gap between the cylinder (4) and the pole (2).

2. The battery cover assembly assembly process according to claim 1, characterized in that, The sealing ring (3) also has a vertical sealing portion (32) that connects to the horizontal sealing portion (31). Step S2 includes: Step S21: The vertical sealing part (32) of the sealing ring (3) is fitted onto the vertical fitting part (21) of the pole post (2), and the two are interference fit; Step S21: Place the pole post (2) along with the sealing ring (3) from the top of the cylinder (4) into the cylinder (4); wherein the vertical sealing part (32) is inserted into the annular body (41).

3. The battery cover assembly assembly process according to claim 2, characterized in that, The holes in the annular body (41) and the holes in the vertical sealing part (32) are prismatic holes, and the outer peripheral walls of the vertical sealing part (32) and the vertical mating part (21) are respectively prismatic in shape to match the corresponding prismatic holes.

4. The battery cover assembly assembly process according to claim 3, characterized in that, The cross-section of the prism hole is rhomboid, and the adjacent sidewalls of the prism hole are transitioned with rounded corners.

5. The battery cover assembly assembly process according to any one of claims 1 to 4, characterized in that, The part of the pole post (2) that presses against the horizontal sealing part (31) is a crimping part (22), and the cross-section of the crimping part (22) is a polygon with a number of sides not less than ten. The hole on the cross-section of the part of the cylinder (4) that surrounds the crimping part (22) with a gap and faces the outer peripheral wall of the crimping part (22) is a polygonal hole with the same number of sides as the polygon. In step S2, during the process of placing the pole post (2) and the sealing ring (3) into the cylinder (4), the pressing part (22) and the cylinder (4) are positioned so that the sides of the polygon and the polygon hole are parallel to each other.

6. The battery cover assembly assembly process according to claim 1, characterized in that, The portion of the cylinder (4) used for flanging (42) is thickened.

7. The battery cover assembly assembly process according to claim 1, characterized in that, Step S3 includes: In step S31, the high-speed riveting machine lowers the intermediate top rod and presses it against the top of the pole post (2), and the horizontal sealing part (31) is compressed; Step S32: The double riveting wheel rotates to roll the upper end flange (42) of the cylinder (4) inward to form an inner trumpet shape; Step S33: The second rolling process flattens the flange (42).

8. The battery cover assembly assembly process according to claim 1, characterized in that, Step S4 includes: Step S41: Place the cover plate body (1) into the injection mold with the top facing upward; Step S42, the injection mold closes, the upper mold ejector pin presses down against the top of the pole post (2), and the horizontal sealing part (31) is compressed; Step S43: Inject injection molding compound into the creepage gap and hold pressure to cure to form the injection molded part (5).

9. The battery cover assembly assembly process according to claim 1, characterized in that, The injection molding part (5) is made of PVS.

10. A battery cover assembly, characterized in that, include: The cover plate body (1) is made of metal and has a cylindrical body (4) that extends through it and protrudes from its top. The inner circumferential wall of the cylindrical body (4) is provided with an annular body (41). The sealing ring (3) has a horizontal sealing portion (31) placed on the annular body (41). The metal pole (2) extends into the cylinder (4) without contacting the cylinder (4) and clamps the horizontal sealing part (31) together with the top surface of the annular body (41). The upper end of the cylinder (4) has a flange (42) that blocks the edge area of ​​the pole (2) with a gap. The injection molding part (5) completely wraps the flange (42) and fills the gap between the cylinder (4) and the pole (2).

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