Thin-Film Battery Can Welding for Strong Sealing Without Deformation
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Solution Overview
Problem
Existing methods for manufacturing thin film can-type batteries face issues with non-welded portions and poor sealing properties due to inadequate adhesion during laser welding, leading to deformation of the metal thin film.
Innovation Solution
A method involving a specific gripping and welding process using jigs to ensure proper alignment and adhesion of the lower and upper can circumferential portions, with controlled heights and pressing surfaces to prevent gaps and enhance bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strong clamping is performed during laser welding to prevent non-welded portions, then adhesion is improved, but deformation of the metal thin film occurs
Solution Approach 1:
The invention changes the geometric parameters of the can structure by forming a protrusion on the inner circumferential surface of the can. This protrusion creates a mechanical interlocking structure that improves adhesion without requiring excessive clamping force during welding, thereby preventing both non-welded portions and thin film deformation
Solution Approach 2:
The protrusion is formed in advance on the inner circumferential surface of the can before the welding process. This preliminary structural modification ensures proper alignment and contact between the can and cover during welding, eliminating the need for strong clamping and preventing deformation
2Shape
If weak clamping is performed during laser welding, then deformation of the metal thin film is avoided, but non-welded portions occur due to insufficient adhesion
Solution Approach 1:
The invention modifies the geometric parameters by adding a protrusion structure to the can's inner circumferential surface. This structural change ensures sufficient adhesion and prevents non-welded portions even with gentle clamping, while the protrusion's design prevents excessive force that could cause deformation
3Reliability
If the height of the accommodation part is increased to improve welding adhesion, then non-welded portions are prevented, but the overall can height increases
Solution Approach 1:
Instead of increasing the overall can height, the invention applies a localized protrusion structure only at the specific location where welding adhesion is needed (inner circumferential surface). This local modification improves welding quality without affecting the overall compact dimensions of the battery can
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
The method significantly improves sealing properties by preventing non-welded portions, ensuring strong adhesion and stable welding, thereby enhancing the performance of thin film can-type batteries.
Implementation Method 1
a welding process of irradiating laser onto a bonding portion that is a point, at which the lower can circumferential portion and the upper cover circumferential portion are bonded to each other, to bond the lower can circumferential portion to the upper cover circumferential portion through laser welding
Data Source
AI summary
A method for manufacturing a secondary battery includes preparing a lower can having an accommodation part to accommodate an electrode assembly, and an upper cover covering an upper opening of the lower can; gripping an end of a lower can circumferential portion and an end of an upper cover circumferential portion at upper and lower portions using upper and lower jigs to weld the lower can circumferential portion extending outward from an edge of the accommodation part to the upper cover circumferential portion that is a circumferential area of the upper cover; and irradiating a laser onto a bonding portion at which the lower can circumferential portion and the upper cover circumferential portion are welded to each other. In the irradiating, a height of the accommodation part is higher than a height of the end of the lower can circumferential portion.