Laminated Battery Packaging Material Deep Drawing Formability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional packaging materials for lithium ion batteries face issues with deep drawing formability, electrolyte resistance, alcohol resistance, adhesion to adhesive tapes, and delamination resistance, particularly when exposed to humid environments or acidic electrolytes, leading to reduced insulation properties and potential short-circuiting due to loose battery cells.
Innovation Solution
A laminated packaging material structure comprising a substrate protective layer made from a cured polyester or acrylic resin with specific reactive groups and isocyanate ratios, an adhesive layer, and a sealant layer, which provides improved electrolyte and alcohol resistance, adhesion, and deep drawing formability, while maintaining insulation properties even when exposed to moisture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If deep drawing is performed on conventional packaging material 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 packaging material uses a composite structure with a substrate layer, adhesive layer, and metal foil layer. The substrate layer provides mechanical strength and formability, while the metal foil layer provides barrier properties. This composite structure allows deep drawing to form recesses for higher energy density while maintaining layer integrity through proper material selection and lamination.
Solution Approach 2:
The invention specifies particular ranges for adhesive layer thickness (1-10 μm) and metal foil layer thickness (5-50 μm) to optimize both deep drawing formability and layer strength. By controlling these parameters, the packaging material can undergo deep drawing to create recesses for increased energy density without breaking the adhesive or metal foil layers.
2Ease of manufacture
If nylon film is used as substrate layer to improve formability, then the deep drawing formability is improved, but the nylon film is dissolved by acidic electrolyte and has low resistance to alcohol
Solution Approach 1:
The invention introduces a barrier layer between the substrate layer and the battery contents. This barrier layer, made of materials with high electrolyte and alcohol resistance, protects the substrate layer from chemical attack while allowing the substrate to maintain its formability. The barrier layer acts as an intermediary that prevents direct contact between the electrolyte/alcohol and the substrate material.
Solution Approach 2:
The packaging material employs a composite structure where the substrate layer provides formability and the barrier layer (adhesive layer + metal foil layer) provides chemical resistance. This composite approach allows each layer to perform its specialized function - the substrate for mechanical forming and the barrier layers for chemical protection against electrolyte and alcohol.
3Strength
If substrate layer has high water absorbability, then the adhesion to adhesive tape is improved, but the insulation properties are reduced and metal foil layer is energized in humid environments
Solution Approach 1:
The barrier layer serves as an intermediary that prevents water penetration to the metal foil layer while allowing adhesive tape to bond to the substrate layer. The substrate layer can maintain its water absorbability for adhesion, but the barrier layer blocks water from reaching the metal foil, preserving insulation properties even in humid environments.
Solution Approach 2:
The composite structure separates the functions of water absorbability (substrate layer for adhesion) and water barrier (barrier layer for insulation). The substrate layer can be made of materials with high water absorbability to ensure strong adhesion to adhesive tapes, while the overlying barrier layers prevent water from reaching the metal foil layer, maintaining electrical insulation in humid conditions.
4Ease of manufacture
If conventional packaging material is used, then the manufacturing cost is low, but interlamellar separation occurs between substrate layer and metal foil layer in warm water environment
Solution Approach 1:
The invention applies preliminary surface treatment to the substrate layer and selects specific adhesive materials that are pre-engineered to resist delamination in warm water environments. By preparing the substrate surface and selecting appropriate adhesives before lamination, the packaging material achieves long-term stability and prevents interlamellar separation without significantly increasing manufacturing cost.
Solution Approach 2:
The invention specifies particular ranges for adhesive layer thickness (1-10 μm) and controls the lamination conditions to optimize delamination resistance. By carefully controlling these parameters during manufacturing, the packaging material achieves improved stability in warm water environments while maintaining cost-effectiveness through efficient use of adhesive material and standard lamination processes.
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 solution enhances the packaging material's resistance to electrolytes and alcohol, maintains strong adhesion to adhesive tapes, and ensures high deep drawing formability and insulation properties, reducing the risk of delamination and short-circuiting, especially in humid conditions.
Implementation Method 1
the curing agent contains an isocyanate other than an alicyclic isocyanate, and an alicyclic isocyanate; and the ratio ([a]/[b]) of the weight of the isocyanate other than an alicyclic isocyanate [a] to the weight of the alicyclic isocyanate [b] is 99/1 to 80/20
Data Source
AI summary
A packaging material for a power storage device, the packaging material including a structure in which at least a substrate protective layer, a substrate layer, an adhesive layer, a metal foil layer, a sealant adhesive layer, and a sealant layer are laminated in this order, wherein the substrate protective layer is a cured product of a raw material containing a polyester resin or an acrylic resin, and a curing agent; the polyester resin or the acrylic resin has reactive groups reactive with the curing agent at a terminal position and/or in a side chain; the curing agent contains an isocyanate other than an alicyclic isocyanate, and an alicyclic isocyanate; and the ratio ([a]/[b]) of the weight of the isocyanate other than an alicyclic isocyanate [a] to the weight of the alicyclic isocyanate [b] is 99/1 to 80/20.