Battery Electrode Notching with Region-Specific Shear Angles
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Solution Overview
Problem
The existing rechargeable battery electrode notching processes often result in desorption of active materials, leading to reversed capacity ratios between negative and positive electrodes, reduced capacity, increased short circuit defects, and abnormal lifespan issues due to foreign materials from desorbed active material.
Innovation Solution
A rechargeable battery electrode substrate notching device and method utilizing a punch with specific shear angles for both straight and round parts, minimizing desorption by forming inclines in the composite layer that control the desorption phenomenon, thereby reducing foreign materials and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional notching is performed without specific shear angles, then the notching process is simple, but active material desorption occurs leading to capacity ratio reversal and reduced battery performance
Solution Approach 1:
The punch is designed with different shear angles for different regions: a first shear angle for straight parts and a second shear angle for round parts. This local differentiation optimizes the notching quality for each specific geometry, preventing active material desorption while maintaining a relatively simple overall punch structure.
Solution Approach 2:
The invention changes the shear angle parameter based on the geometry of the electrode substrate being notched. By adjusting the shear angle according to whether the region is straight or round, the process achieves precise control over material separation, eliminating desorption issues without requiring complex additional equipment.
2Productivity
If conventional notching is performed without controlling shear angles, then the notching process is fast, but foreign materials are generated increasing short circuit defect rates
Solution Approach 1:
The punch incorporates region-specific shear angles optimized for different electrode geometries. This local optimization ensures clean separation without active material desorption or foreign material generation, maintaining high productivity while significantly reducing short circuit defects caused by foreign materials.
3Ease of manufacture
If conventional notching is performed without specific shear angles, then the process is simple, but capacity ratio between negative and positive electrodes is reversed
Solution Approach 1:
The punch design implements different shear angles for straight and round regions, creating optimized separation conditions for each geometry. This prevents active material desorption that would otherwise alter the capacity ratio, achieving precise capacity control while keeping the manufacturing process simple and straightforward.
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 effectively minimizes desorbed active material, preventing capacity ratio reversal, reducing short circuit defects, and extending the lifespan of rechargeable batteries by optimizing the notching process with controlled shear angles.
Implementation Method 1
An active material may be separated from the electrode substrate in the notching process, and this phenomenon may be referred to as desorption
Data Source
AI summary
A rechargeable battery electrode substrate notching device includes a die and a punch notching an electrode substrate into an electrode having a straight part and a round part by being lifted toward the die while the electrode substrate is installed on the die, wherein the punch includes a round shear part corresponding to the round part.