Composite Battery Lid Structure for Stronger Pouch Film Sealing
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Solution Overview
Problem
The joining strength between the outer package film and the metal lid is low in electrical storage devices, leading to potential sealing issues with the electrode assembly.
Innovation Solution
A lid structure comprising a metal lid main body with a resin cover, featuring through-holes, recessed or projecting portions, and a rough surface, enhances the bonding with the outer package film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal lid is used for the outer packaging, then the strength and rigidity of the lid are improved, but the joining strength between the lid and the outer package film deteriorates
Solution Approach 1:
The lid is constructed as a composite structure combining a metal lid main body with a resin cover portion. The metal main body provides strength and rigidity, while the resin cover portion provides good joining properties with the outer package film through heat sealing. This composite material approach resolves the contradiction by integrating materials with complementary properties.
Solution Approach 2:
Different portions of the lid have different material properties optimized for their specific functions. The lid main body uses metal material for structural strength, while the cover portion uses resin material for sealing capability. This local differentiation of material quality allows each portion to excel at its intended function without compromising the other.
2Manufacturing precision
If a smooth surface is used on the cover portion, then the manufacturing precision is improved, but the joining strength with the outer package film deteriorates
Solution Approach 1:
The cover portion features a locally modified rough surface in the sealing region while maintaining overall manufacturing precision. The rough surface is specifically applied where heat sealing with the outer package film occurs, enhancing joining strength without compromising the precision of the overall lid structure.
Solution Approach 2:
The surface roughness parameter of the cover portion is optimized to enhance heat sealing performance. By controlling the roughness within a specific range (Rz: 0.01 μm or more and 500 μm or less), the joining strength with the outer package film is improved while maintaining manufacturability.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
This lid body is used for the exterior body of a power storage device and comprises: a lid main body configured including a metal material; and a covering body configured including a resin material and covering a part of the lid main body. The lid main body has a covered part covered by the covering body. The covered part has at least one of a through hole, a recessed part recessed to the side opposite to the covering body, or a protruding part protruding toward the covering body.