Battery Packaging Laminate for Curl-Free Molding Insulation
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Solution Overview
Problem
Battery packaging materials face challenges in achieving slimness, excellent moldability, preventing curling after molding, and ensuring sufficient surface insulation quality, particularly for large batteries used in vehicles, where pinholes and cracks occur during molding, leading to reduced insulation quality and impaired battery function.
Innovation Solution
A laminate structure comprising a stretched polyester film layer, an aluminum alloy foil layer, and a heat-sealable resin layer, with specific thicknesses and dielectric breakdown voltage, enhances moldability and insulation while preventing curling, using polyesters like polyethylene terephthalate and polybutylene terephthalate, and chemical treatments for the aluminum alloy foil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a film-shaped laminate packaging material is used to reduce thickness and weight, then weight reduction is achieved, but pinholes and cracks easily occur during molding
Solution Approach 1:
The patent uses a composite laminate structure consisting of a polyamide base material layer and a polyester outer layer. This composite structure combines the advantages of both materials: the polyamide provides excellent moldability and pinhole resistance, while the polyester layer contributes to overall strength and dimensional stability, preventing cracking during molding processes.
Solution Approach 2:
The patent applies different material properties to different layers of the packaging structure. The inner polyamide layer is optimized for moldability and defect prevention during forming, while the outer polyester layer provides structural integrity. This local differentiation of material qualities allows the thin packaging to maintain both formability and manufacturing precision.
2Manufacturing precision
If a polyamide film is used as base material to improve moldability, then pinhole and crack resistance is improved, but insulation quality deteriorates
Solution Approach 1:
The patent creates a functional composite where the polyamide base layer handles the moldability requirement while the polyester outer layer provides the insulation function. This separation of functions within the laminate structure allows both contradictory requirements to be satisfied simultaneously without compromising either moldability or insulation quality.
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 laminate structure provides a slim, moldable, and highly insulating battery packaging material that effectively prevents curling and maintains insulation quality, even under severe conditions, ensuring reliable battery performance.
Implementation Method 1
a dielectric breakdown voltage of a surface on a side of the stretched polyester film layer is 13 kV or more
Implementation Method 2
an aluminum alloy foil layer
Implementation Method 3
a heat-sealable resin layer is heat-weld to itself
Data Source
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AI summary
Provided is a battery packaging material which is slim, has excellent moldability, effectively prevents curl after molding, and moreover, is capable of imparting sufficient surface insulation to a battery. This battery packaging material is configured from a laminate which is at least provided with a polyester film layer, an aluminum alloy foil layer, and a thermally-fusible resin layer in this order. The thickness of the polyester film layer is 23-27 µm, the thickness of the aluminum alloy foil layer is 33-37 µm, the thickness of the thermally-fusible resin layer is 55-65 µm, the thickness of the laminate is 130 µm or less, and the insulation breakdown voltage of the polyester film layer-side surface is 13 kV or greater.