Pouch Battery Case Laminate for Deep Draw and Puncture Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pouch type battery cases face limitations in formability due to low tensile strength, elongation, and puncture resistance, leading to increased dead space and reduced energy efficiency in secondary batteries.
Innovation Solution
A pouch type battery case is developed using a pouch film laminate with an aluminum alloy gas barrier layer of specific thickness and grain size, combined with a sealant and surface protection layers, enhancing tensile strength, elongation, and puncture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional pouch film laminate is used for the battery case, then the manufacturing process is simple, but the tensile strength and elongation are insufficient leading to poor formability
Solution Approach 1:
The pouch film laminate is constructed as a multi-layer composite material comprising a metal layer (aluminum or stainless steel), a polymer layer (such as polyethylene terephthalate or polyvinylidene fluoride), and optionally a ceramic layer. This composite structure combines the high strength and barrier properties of metal with the flexibility and formability of polymer, resolving the contradiction between tensile strength and manufacturing complexity.
Solution Approach 2:
The patent optimizes specific parameters of the pouch film laminate including thickness (50-150 μm), metal layer composition (aluminum alloy with specific elements like magnesium, silicon, or iron), and polymer layer properties. By controlling these parameters, the laminate achieves enhanced tensile strength and elongation while maintaining reasonable manufacturing complexity.
2Stability of the object's composition
If a conventional pouch film laminate is used, then the manufacturing process is simple, but the elongation is limited reducing formability
Solution Approach 1:
The multi-layer composite structure allows each layer to contribute different properties: the metal layer provides strength while the polymer layer provides ductility and elongation. This composite approach enables the pouch film to undergo significant deformation during forming processes without breaking, achieving high elongation (greater than 5%) while managing structural complexity.
Solution Approach 2:
The pouch film laminate is designed with different layers having different local properties optimized for specific functions. The polymer layer is positioned to provide local flexibility and elongation where needed during forming, while the metal layer provides overall structural integrity. This local differentiation resolves the contradiction between elongation and complexity.
3Volume of stationary object
If the cup portion is formed deeper to reduce dead space, then the accommodating space volume increases, but the pouch film laminate cannot withstand the forming stress
Solution Approach 1:
The multi-layer composite pouch film laminate combines metal (providing puncture resistance) with polymer (providing formability). This composite structure enables the film to withstand the high stresses of deep drawing processes while achieving deeper cup portions and larger accommodating space volume, resolving the contradiction between volume and strength.
Solution Approach 2:
The patent optimizes the thickness and composition parameters of the pouch film laminate to achieve the right balance between strength and formability. By controlling metal content, layer thickness, and material composition, the laminate can endure the forming stress required for deep cup portions while maintaining puncture resistance, enabling increased accommodating volume without sacrificing strength.
4Volume of stationary object
If the radius of filleting is reduced at edges, then the energy efficiency to volume increases, but the conventional pouch film laminate cannot be formed properly
Solution Approach 1:
The composite pouch film laminate with its multi-layer structure provides both the strength and flexibility needed to achieve tight filleting with small radii. The metal layer maintains structural integrity during sharp bending while the polymer layer allows the necessary deformation, enabling reduced filleting radius and improved energy efficiency to volume ratio.
Solution Approach 2:
By optimizing parameters such as pouch film thickness, metal layer composition, and polymer layer properties, the laminate achieves the ductility required for tight filleting. This parameter optimization enables manufacturing precision in filleting (smaller radii) while maintaining the structural integrity needed for high energy efficiency to volume ratio.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The present invention relates to a pouch type battery case which includes a pouch film laminate including a sealant layer, a gas barrier layer, and a surface protection layer, wherein the sealant layer is formed of a first polymer that is an innermost layer, the surface protection layer is formed of a second polymer that is an outermost layer, and the gas barrier layer is laminated between the surface protection layer and the sealant layer and is formed of an aluminum alloy film having a thickness of 60 µm to 100 µm and a grain size of 10 µm to 13 µm.