Power Storage Packaging Material Deep Forming
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Solution Overview
Problem
Existing packaging materials for power storage devices face challenges in achieving both sufficient heat resistance and excellent formability without causing pinholes or cracks, especially during deep depth forming and under severe environments like high temperature and high humidity, where delamination issues arise.
Innovation Solution
A packaging material comprising a heat-resistant resin layer, a heat-fusible resin layer, and a metal foil layer bonded via an electron beam curable resin composition, which includes acrylate resin, photo-radical polymerization initiators, silane coupling agents, and phosphoric acid-containing (meth) acrylates, providing enhanced adhesion and resistance to delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a packaging material uses conventional adhesive compositions containing resin with active hydrogen groups, multifunctional isocyanates, and polyfunctional amine compounds, then the material achieves heat resistance, but delamination occurs between the metal foil layer and outer resin layer during deep depth forming or under severe environments
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive layer by incorporating phosphoric acid-containing (meth)acrylate in specific amounts (0.1-10 mass%) alongside silane coupling agents and electron beam curable resins. This parameter modification enables the adhesive to maintain heat resistance while preventing delamination during deep depth forming and under severe environmental conditions through improved chemical bonding characteristics.
Solution Approach 2:
The patent creates a composite adhesive system combining multiple components: electron beam curable resin, silane coupling agent, phosphoric acid-containing (meth)acrylate, and optionally epoxy resin or oxetane resin. This composite material approach synergistically combines the heat resistance of conventional adhesives with the delamination prevention capabilities of silane and phosphoric acid components, achieving both required properties simultaneously.
2Ease of manufacture
If a packaging material uses polyamide film or polyester film with high tensile strength for deep depth forming, then formability is improved, but stress concentrates locally on the metal foil causing pinholes and cracks
Solution Approach 1:
The patent modifies the adhesive layer composition parameters to include phosphoric acid-containing (meth)acrylate (0.1-10 mass%) and silane coupling agent (0.1-5 mass%) in controlled amounts. These parameter changes enable the adhesive to accommodate the stress distribution during deep depth forming of high-strength films, preventing stress concentration on the metal foil while maintaining formability.
Solution Approach 2:
The adhesive layer acts as an intermediary between the metal foil and outer resin layer, with phosphoric acid-containing (meth)acrylate and silane coupling agent providing flexible bonding characteristics. This intermediary layer absorbs and distributes stress during deep depth forming, preventing direct stress transmission to the metal foil that would cause pinholes and cracks.
3Device complexity
If conventional adhesive compositions are used to bond the metal foil layer and outer resin layer, then the bonding process is simple, but delamination occurs under high temperature and high humidity conditions
Solution Approach 1:
The patent develops a composite adhesive composition integrating electron beam curable resin, silane coupling agent, and phosphoric acid-containing (meth)acrylate. This composite formulation maintains relative simplicity in application while providing superior bonding stability under high temperature and high humidity conditions through enhanced chemical crosslinking and adhesion mechanisms.
Solution Approach 2:
The patent replaces conventional thermal or chemical curing mechanisms with electron beam curing. This substitution enables rapid curing without high heat exposure, reducing thermal stress on the bonding interface while the phosphoric acid-containing (meth)acrylate and silane coupling agent provide chemical bonding stability under severe environmental conditions.
4Adaptability or versatility
If deep depth forming is performed on packaging material with conventional structure, then the packaging can accommodate complex battery shapes, but pinholes and cracks occur on the metal foil layer
Solution Approach 1:
The adhesive layer with phosphoric acid-containing (meth)acrylate and silane coupling agent serves as a flexible intermediary that accommodates the deformation during deep depth forming. This intermediary layer allows the packaging to adapt to complex battery shapes while preventing stress concentration that would cause pinholes and cracks on the metal foil layer.
Solution Approach 2:
The patent modifies the adhesive composition parameters to include specific amounts of phosphoric acid-containing (meth)acrylate (0.1-10 mass%) and silane coupling agent (0.1-5 mass%), which change the viscoelastic properties of the adhesive. These parameter changes enable the adhesive to flexibly accommodate deep depth forming deformation while maintaining surface integrity and preventing defect formation.
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 ensures heat resistance and excellent formability without pinholes or cracks, effectively preventing delamination even under severe conditions, while reducing production time and improving efficiency through electron beam curing.
Implementation Method 1
an outer adhesive layer composed of a cured film of an electron beam curable resin composition
Implementation Method 2
phosphoric acid-containing (meth) acrylates, providing enhanced adhesion
Data Source
AI summary
Provided is a packaging material for a power storage device capable of securing excellent formability without causing pinholes and/or cracks even when deep depth forming is performed and also capable of sufficiently preventing delamination even when deep depth forming is performed or even when it is used under severe environments, such as, e.g., high temperature and high humidity.[Solving means] The packaging material for a power storage device has a configuration including a heat resistant resin layer 2 serving as an outer layer, a heat fusible resin layer 3 serving as an inner layer, and a metal foil layer 4 disposed between both the two layers. The heat resistant resin layer 2 is composed of a heat resistant resin film with a hot water shrinkage percentage of 1.5% to 12%. The heat resistant resin layer 2 and the metal foil layer 4 are bonded via an outer adhesive layer 5 composed of a cured film of an electron beam curable resin composition.