Power Storage Packaging Material Deep Drawing Formability
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Solution Overview
Problem
Conventional packaging materials for lithium ion batteries face issues with deep drawing formability and electrolyte resistance, leading to potential delamination between the substrate and metal foil layers, especially when exposed to acidic electrolytes.
Innovation Solution
A power storage device packaging material comprising a substrate protective layer formed from a cured product of a polyester resin and polyisocyanate compound, with a glass transition temperature of 60 to 140°C and a thickness of 1 to 5 μm, along with an anticorrosion treatment layer on the metal foil, to enhance formability and electrolyte resistance while suppressing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If deep drawing is performed on conventional packaging materials to form a deep recess, then the energy density is improved, but the adhesive layer and metal foil layer may be broken
Solution Approach 1:
The patent modifies the substrate protective layer by controlling its glass transition temperature to be 60 to 140°C and thickness to 1 to 5 μm, which changes the material's mechanical properties to allow deep drawing without breaking the adhesive or metal foil layers while maintaining layer integrity
Solution Approach 2:
The patent uses a composite structure with multiple layers including a substrate protective layer, substrate layer, adhesive layer, and metal foil layer, where each layer is specifically designed to work together to prevent delamination and breaking during deep drawing processes
2Ease of manufacture
If a nylon film is used as a substrate layer to improve formability, then the deep drawing formability is improved, but the nylon film is dissolved when it comes into contact with acidic electrolyte
Solution Approach 1:
The patent introduces a substrate protective layer as an intermediary between the substrate layer and the external environment, which protects the substrate layer from direct contact with acidic electrolyte while allowing the substrate layer to maintain good deep drawing formability
Solution Approach 2:
The patent specifies that the substrate protective layer should have a glass transition temperature of 60 to 140°C and a thickness of 1 to 5 μm, which optimizes both the formability and electrolyte resistance properties of the packaging material
3Reliability
If power storage devices are stored in a warm water environment for long-term reliability testing, then the reliability is evaluated, but interlayer separation occurs between substrate layer and metal foil layer
Solution Approach 1:
The patent controls the glass transition temperature of the substrate protective layer to be 60 to 140°C, which maintains the adhesive properties of the layers during long-term reliability testing in warm water environments, preventing interlayer separation
Solution Approach 2:
The patent uses a composite structure with specifically designed layers including a substrate protective layer, substrate layer, and metal foil layer, where the adhesive layer between substrate layer and metal foil layer is optimized to prevent delamination during long-term storage in warm water environments
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 proposed solution provides improved deep drawing formability and electrolyte resistance, effectively preventing delamination and ensuring the stability of the packaging material even when exposed to acidic environments.
Implementation Method 1
a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer in this order, where the substrate protective layer is a cured product of a raw material containing a polyester resin and a polyisocyanate compound
Implementation Method 2
a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer
Data Source
AI summary
The present invention relates to a power storage device packaging material. The packaging material includes at least a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer in this order. The substrate protective layer is a cured product of a raw material containing a polyester resin and a polyisocyanate compound, has a glass transition temperature (Tg) of 60 to 140° C., and has a thickness of 1 to 5 μm, with a ratio of the thickness of the substrate protective layer to the thickness of the substrate layer being 35% or less.