Pouch Battery Case Rounded Edge Structure for 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, curvature radius, and edge clearance, which affect the size and shape of secondary batteries.
Innovation Solution
The design includes a pouch-type battery case with rounded punch edges and a bridge, a specific moisture barrier layer thickness and grain size, and a layered structure of the pouch film to improve moldability and accommodate a larger electrode assembly, resulting in a more efficient energy density and aesthetically pleasing design.
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 manufacturing cost is reduced, but the moldability deteriorates and the curvature radius and clearance of the cup part edge cannot be improved
Solution Approach 1:
The patent changes the physical parameters of the aluminum alloy moisture barrier layer by controlling the crystal grain size to be 5 μm or less and the thickness to be 30 μm or more. This parameter optimization enables the material to achieve both cost-effectiveness and improved moldability, allowing for smaller curvature radii and better edge clearance in the cup part
Solution Approach 2:
The patent creates a composite pouch film structure by combining the aluminum alloy moisture barrier layer with specific polymer layers (inner layer and outer layer). This composite structure enhances the overall moldability while maintaining the protective function of the aluminum barrier, enabling precise shaping with small curvature radii
2Quantity of substance
If the curvature radius of the cup part edge is reduced to improve energy density, then the energy density relative to volume increases, but the moldability deteriorates and manufacturing becomes difficult
Solution Approach 1:
The patent achieves small curvature radii (5 μm or less crystal grain size in aluminum layer) by optimizing the material parameters, enabling the cup part to accommodate larger electrode assemblies and reduce unnecessary volume, thereby increasing energy density while remaining manufacturable
Solution Approach 2:
The patent uses a flexible pouch film structure with optimized thickness and composition that can be molded into sharp edges with small curvature radii. The film's flexibility allows it to conform to the desired shape while maintaining structural integrity, enabling high energy density designs
3Volume of stationary object
If the cup part is molded deeply to increase accommodation space, then the volume increases, but the edge clearance and curvature radius cannot be improved due to material limitations
Solution Approach 1:
The patent optimizes the aluminum alloy layer parameters (crystal grain size ≤5 μm, thickness ≥30 μm) to enable deep molding while maintaining edge quality. This allows the cup part to achieve both deep accommodation space and sharp edge clearance simultaneously
Data Source
AI summary
A pouch-type battery case according to an embodiment of the present invention includes a cup part configured to accommodate an electrode assembly, in which electrodes and separators are stacked, therein, wherein the cup part includes a plurality of punch edges configured to connect a plurality of outer walls configured to surround a periphery thereof to a bottom part, respectively, and each of the punch edge being rounded with a curvature radius of 1 mm or less.