Pouch Battery Case Structure for Thin Bridges and Higher Energy Density
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Solution Overview
Problem
Pouch-type battery cases face limitations in increasing energy density relative to volume, achieving an elegant outer appearance, and enhancing marketability due to constraints in moldability, particularly with thick bridges and narrow bat-ears, which affect the depth and curvature of cup parts and the overall shape of secondary batteries.
Innovation Solution
A pouch-type battery case design featuring a bridge thickness of 2 mm or less, rounded curvature radii, and a specific layer structure including a moisture barrier layer with a grain size of 10 μm to 13 μm and a sealant layer thickness of 60 μm to 100 μm, improving moldability and reducing the size of bat-ears, resulting in increased energy density and a more elegant appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the moisture barrier layer uses aluminum alloy with large crystal grain size and thin thickness, then the material is easier to process, but the moldability deteriorates and the bridge thickness and folding part width cannot be reduced
Solution Approach 1:
The patent changes the grain size parameter of the aluminum alloy moisture barrier layer from large (related art) to small (10-13 μm), which fundamentally alters the material's formability characteristics. This parameter change enables the pouch film to be molded into shapes with thin bridges (2 mm or less) and narrow folding parts while maintaining material integrity and preventing defects during the molding process.
2Quantity of substance
If the cup part depth is increased to improve energy density, then the volume utilization improves, but the moldability limitations prevent achieving the required depth with traditional materials
Solution Approach 1:
By changing the grain size parameter of the aluminum alloy to 10-13 μm, the material gains the formability required to mold deep cup parts without developing defects. This enables the pouch-type battery case to achieve greater cup part depth, thereby increasing the volume available for electrode assemblies and improving energy density.
3Quantity of substance
If the bridge thickness is reduced to 2 mm or less to improve energy density, then the volume efficiency increases, but the moldability deteriorates with traditional aluminum alloy specifications
Solution Approach 1:
The patent applies parameter changes to the aluminum alloy grain size (10-13 μm) which enables the molding process to successfully produce bridges with thickness of 2 mm or less. The refined grain structure provides the necessary ductility and formability to create thin bridge structures without causing material failure or molding defects.
4Quantity of substance
If the folding part width is reduced to improve energy density, then the volume utilization improves, but the moldability limitations prevent achieving narrow folding parts
Solution Approach 1:
By refining the aluminum alloy grain size to 10-13 μm, the material achieves the formability required to mold narrow folding parts. This parameter change allows the pouch film to be folded into compact configurations with reduced folding part width while maintaining structural integrity and preventing defects during the folding and sealing 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 improved moldability and reduced size of bat-ears enhance energy density and marketability by allowing deeper cup parts and a more compact, aesthetically pleasing battery design.
Implementation Method 1
a moisture barrier layer which is formed as an aluminum alloy thin film having a grain size of 10 μm to 13 μm
Data Source
AI summary
A pouch-type battery case according to an embodiment of the present invention for achieving the above objects includes: a first case and a second case, in which cup parts each of which is configured to accommodate an electrode assembly, in which electrodes and separators are stacked, therein is formed, respectively; and a bridge formed between the two cup parts, wherein the bridge has a thickness of 2 mm or less.