Pouch Secondary Battery Case Structure for Short Bat Ears
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Solution Overview
Problem
Pouch-type secondary batteries face limitations in energy density, volume efficiency, and aesthetic appeal due to constraints in moldability and curvature of the pouch film, leading to reduced marketability.
Innovation Solution
The design includes a pouch-type secondary battery with a battery case comprising a cup part, folding part, and bat ears, featuring specific dimensions and angles, along with a moisture barrier layer made of an aluminum alloy thin film with controlled grain size and thickness, enhancing moldability and reducing bat ear length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pouch film is molded deeply to increase cup part depth, then the volume of the battery case increases, but the curvature radius and clearance of the edge cannot be improved due to deteriorated moldability
Solution Approach 1:
The patent changes the physical parameters of the pouch film by controlling the thickness (50-80 μm) and grain size (10-13 μm) of the aluminum alloy moisture barrier layer. These parameter changes enable the film to achieve both deep cup part molding and acceptable edge curvature without compromising moldability.
2Quantity of substance
If the volume ratio of electrode assembly to cup part is increased, then energy density improves, but the bat ear size cannot be reduced further
Solution Approach 1:
The patent reduces the bat ear length to 1.5 mm or less by optimizing the pouch film parameters (thickness and grain size), enabling higher volume utilization and improved energy density while maintaining structural integrity.
3Manufacturing precision
If the pouch film moldability is improved, then the curvature radius and clearance can be optimized, but the depth of the cup part cannot be molded deeply
Solution Approach 1:
The patent simultaneously optimizes two critical parameters of the aluminum alloy moisture barrier layer: thickness (50-80 μm) and grain size (10-13 μm). This dual parameter control enables the pouch film to achieve both deep cup part molding and acceptable edge curvature, resolving the contradiction between depth and moldability.
4Shape
If the outer appearance is made sharp and elegant, then marketability improves, but the manufacturing complexity increases
Solution Approach 1:
The patent achieves sharp and elegant outer appearance by precisely controlling the pouch film parameters (thickness and grain size), which enables better moldability and sharper edges without requiring complex manufacturing 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
This design increases energy density by minimizing bat ear size and space between the electrode assembly and outer walls, improves cooling efficiency, and enhances the battery's outer appearance, thereby improving marketability.
Implementation Method 1
a moisture barrier layer made of an aluminum alloy thin film with controlled grain size and thickness
Data Source
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AI summary
A pouch-type secondary battery according to an embodiment of the present invention for achieving the above object includes: an electrode assembly in which electrodes and separators are stacked; a pouch-type battery case comprising a cup part configured to accommodate the electrode assembly therein, wherein the battery case includes: a first case and a second case, of which at least one comprises a cup part; a folding part configured to integrally connect the first case to the second case; and a bat ear protruding outward from a portion of each of opposing ends of the folding part, wherein the bat ear has a length of 1.5 mm or less.