Battery Packaging Material Resolving Pinhole Contradiction
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Solution Overview
Problem
Conventional battery packaging materials face challenges in achieving both excellent moldability and electrolytic solution resistance, particularly when using polyester films, as they tend to generate pinholes and cracks during molding, which can lead to short-circuits and reduced productivity.
Innovation Solution
A battery packaging material with a laminate structure comprising a polyester film base material layer, an aluminum foil metal layer with high yield strength, and a biaxially stretched film including both polyester and polyamide resin layers, which reduces pinhole and crack generation during molding while maintaining high electrolytic solution resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyester film is used as a base material layer to improve electrolytic solution resistance, then electrolytic solution resistance is improved, but pinholes are easily generated during molding
Solution Approach 1:
The patent uses a composite laminate structure consisting of a polyester film base material layer and a polyamide resin coating layer. The polyester film provides excellent electrolytic solution resistance, while the polyamide resin coating layer improves moldability and prevents pinhole formation during deep drawing. This composite structure resolves the contradiction by combining materials with complementary properties.
2Weight of moving object
If a film-shaped laminate is used to achieve thickness reduction and weight reduction, then thickness and weight are reduced, but pinholes and cracks are easily generated during molding
Solution Approach 1:
The patent specifies that the polyamide resin coating layer should have a thickness of 1 μm to 10 μm, and the polyester film base material should have a thickness of 3 μm to 20 μm. By optimizing these parameter ranges, the patent achieves both weight reduction and improved moldability, preventing pinhole and crack generation during deep drawing while maintaining the benefits of thin-film construction.
3Manufacturing precision
If a nylon film is used as a base material to improve moldability, then moldability is improved, but electrolytic solution resistance deteriorates
Solution Approach 1:
The patent divides the base material into two functional segments: a polyester film base material layer that provides electrolytic solution resistance, and a polyamide resin coating layer that provides improved moldability. This segmentation allows each layer to perform its specific function optimally, with the polyester film preventing electrolyte penetration and the polyamide layer enabling deep drawing without pinholes.
Data Source
AI summary
To provide a technique for a battery-packaging material made of a film-form laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are laminated successively, wherein: electrolytic solution resistance is further improved by including a polyester film in the base material layer; cracks and pinholes are less likely to be created at the time of forming the polyester-film-including base material layer; and formability is improved. This battery-packaging material is made of a laminate in which at least a base material layer, an adhesive layer, a metal layer, and a sealant layer are laminated successively, wherein: the base material layer includes a polyester film; and the metal layer is an aluminum foil in which the 0.2% proof stress at the time of performing a tensile test in a direction parallel to the rolling direction is from 55 to 140 N/mm2.