Flexible Battery Gasket Uneven Pattern Stress Distribution
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Solution Overview
Problem
Flexible secondary batteries face instability and capacity retention issues when repeatedly bent due to uneven stress distribution and potential damage from concentrated stress during bending.
Innovation Solution
A flexible secondary battery design featuring a gasket with an uneven pattern on its surface and sides, which surrounds the electrode assembly, and sealing sheets with insulating and metal layers, allowing for uniform stress distribution and improved reliability through the use of a flexible material and varying thickness and width in the bendable area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional sealing structure is used, then the battery can be assembled, but the battery shows significant capacity reduction after repeated bending due to uneven stress distribution
Solution Approach 1:
The gasket incorporates an uneven pattern with varying thickness and width specifically in the bendable area, creating local structural variations that adapt to bending stresses. This local quality modification allows the gasket to maintain sealing functionality while distributing stress uniformly during repeated bending cycles, preventing capacity reduction.
Solution Approach 2:
The gasket's physical parameters (thickness and width) are intentionally varied in the bendable area to optimize stress distribution. By changing these geometric parameters locally, the structure accommodates bending deformations without creating stress concentration points, thereby maintaining battery reliability after repeated bending.
2Reliability
If the gasket thickness is increased to improve sealing, then sealing performance improves, but flexibility and bendability deteriorate
Solution Approach 1:
The gasket employs different thickness profiles in different regions: thicker sections provide enhanced sealing where needed, while thinner sections in the bendable area maintain flexibility. This local differentiation resolves the contradiction between sealing performance and bendability.
Solution Approach 2:
Instead of uniformly increasing thickness in one dimension, the design varies thickness and width across multiple dimensions in the bendable area. This multi-dimensional parameter variation achieves both adequate sealing and maintained flexibility during bending operations.
Data Source
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AI summary
A flexible secondary battery includes an electrode assembly that includes a first electrode layer, a second electrode layer, and a separator that is disposed between the first electrode layer and the second electrode layer; a gasket that is flexible and surrounds an edge of the electrode assembly; a first sealing sheet that is attached to a first surface of the gasket; and a second sealing sheet that is attached to a second surface of the gasket opposite the first surface, wherein an uneven pattern is formed on a bendable area of the gasket.