Pouch Battery Case Edge Geometry for Deep Draw Moldability
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Solution Overview
Problem
Existing pouch-type secondary batteries face limitations in energy density, marketability due to large crystal grain size in metal barrier layers, leading to poor moldability and increased empty space, and are prone to cracks and pin-holes.
Innovation Solution
A pouch-type battery case with edges having smaller curvature radii and improved moldability, using a pouch film with enhanced tensile strength and elongation, allowing for deeper cup parts and reduced empty space, while minimizing the risk of cracks and pin-holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a pouch film with a metal barrier layer having large crystal grain size and thin thickness is used, then the manufacturing cost is reduced, but the moldability is deteriorated and cracks and pin-holes are formed
Solution Approach 1:
The patent changes the physical parameters of the metal barrier layer by controlling the crystal grain size to be 5 μm or less and the thickness to be 10 μm or more. This parameter optimization resolves the contradiction by enabling both thin film usage and good moldability, preventing cracks and pin-holes during the drawing-molding process while maintaining cost effectiveness.
2Quantity of substance
If the cup part is molded with deep depth, then the energy density is increased, but the curvature radius of edges becomes large and moldability is limited
Solution Approach 1:
The patent optimizes the material parameters (crystal grain size ≤5 μm, thickness ≥10 μm) to enable the pouch film to withstand the stresses of deep drawing-molding. This allows the cup part to be molded with deep depth and small edge curvature radius simultaneously, increasing energy density while maintaining excellent moldability and preventing defects.
3Device complexity
If the pouch film has poor tensile strength and elongation, then the manufacturing process is simplified, but cracks and pin-holes are formed during molding
Solution Approach 1:
The patent specifies optimal parameters for the metal barrier layer (crystal grain size ≤5 μm, thickness ≥10 μm) that inherently provide both sufficient tensile strength and elongation properties. This resolves the contradiction by enabling the manufacturing process to remain relatively simple while achieving high reliability and preventing cracks and pin-holes during the drawing-molding process.
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 increases energy density, enhances the outer appearance, and improves marketability by reducing empty space and minimizing defects, resulting in a more elegant and durable secondary battery design.
Implementation Method 1
the cup part is molded by drawing-molding the pouch film, each of the edges of the cup part has smaller curvature radius
Data Source
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AI summary
A pouch-type battery case according to an embodiment of the present invention may include: a cup part having a recessed shape; and a side disposed around at least a portion of the cup part. The cup part may include: a base surface; a plurality of circumferential surfaces; a plurality of die edges connecting the plurality of circumferential surfaces and the side to each other and formed to be rounded; and a plurality of thickness edges connecting the plurality of circumferential surfaces to each other and formed to be rounded. In the pouch-type battery case, when a curvature radius of each of the die edges is Rd, and a curvature radius of each of the thickness edges is Rt, a conditional expression: Rd ≤ Rt < 3*Rd is satisfied.