Square Battery Sealing Plate Structure for Safer Laser Welding
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Solution Overview
Problem
Existing square batteries face issues with laser penetration during welding, which can cause thermal damage to the electrode assembly and potential explosion of welded portions due to concentrated heat.
Innovation Solution
A manufacturing method for a square battery that involves welding a sealing plate to a case body using laser irradiation, where the sealing plate has a cover portion and an inserting portion, with controlled gaps and energy distribution to prevent laser penetration and diffuse heat, forming an 'R' shape at the corners to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is used to join the sealing plate to the case body, then welding strength and productivity are improved, but laser penetration into the battery interior causes thermal damage to the electrode assembly
Solution Approach 1:
The sealing plate is divided into a cover portion and an inserting portion, creating a structured configuration where the inserting portion extends into the case body interior. This segmentation allows the welding process to be localized to the boundary region while the inserting portion acts as a physical barrier to prevent laser penetration into the electrode assembly space.
Solution Approach 2:
The inserting portion of the sealing plate serves as an intermediary structure between the welding zone and the electrode assembly. During laser welding, this inserting portion intercepts and blocks the laser beam, preventing it from reaching the electrode assembly while still allowing the welding process to proceed effectively at the sealing plate-case body interface.
2Productivity
If laser welding is applied to the sealing plate and case body, then manufacturing efficiency is improved, but concentrated heat causes explosion of welded portions
Solution Approach 1:
The welding structure is designed with local quality variations through the cover portion and inserting portion configuration. The inserting portion creates a localized heat diffusion path within the case body interior, while the cover portion maintains the welding interface quality. This local structural differentiation allows efficient welding while preventing heat concentration that would cause explosions.
Solution Approach 2:
The inserting portion extends the sealing plate structure into the third dimension (into the case body interior), creating a spatial configuration that naturally diffuses heat in multiple directions. This dimensional extension prevents heat concentration at the welding interface, reducing the risk of explosions while maintaining welding efficiency.
3Reliability
If the sealing plate fully covers the opening edge, then sealing performance is improved, but laser penetration risk increases
Solution Approach 1:
The sealing plate is segmented into a cover portion for sealing and an inserting portion for laser protection. The cover portion maintains full coverage of the opening edge for sealing performance, while the inserting portion extends inward to block laser penetration, achieving both sealing reliability and laser safety through functional segmentation.
Solution Approach 2:
The inserting portion acts as an intermediary barrier that extends from the sealed opening into the case body interior. This intermediary structure maintains the sealing function at the opening while simultaneously serving as a laser beam blocker, preventing direct laser access to the electrode assembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents damage to the electrode assembly and shrink film while ensuring robust welding by diffusing heat, thereby preventing explosions and maintaining structural integrity.
Implementation Method 1
welding a sealing plate to a case body using laser irradiation
Data Source
AI summary
Provided is a square battery 100 that includes a battery case 10 and an electrode assembly 20 housed in the battery case 10. The battery case 10 includes a case body 12 having a rectangular prism shape with openings 13 at both ends thereof and sealing plates 14 that seal the openings 13. The sealing plate 14 has a cover portion 14a that covers an edge 13a of the opening of the case body 12 and an inserting portion 14b inserted into the interior of the case body 12 from the cover portion 14a along the inside of the case body 12. The cover portion 14a and the case body 12 are welded together along the edge 13a of the opening of the battery case 10.