Current Collector Curved Portion Thickness for Crack Prevention
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Solution Overview
Problem
Conventional energy storage devices face stability issues due to stress concentration at bent portions of current collectors, leading to cracks and reduced stability when formed in compact shapes.
Innovation Solution
A current collector configuration with a curved portion between two plate portions, where the thickness of the curved portion is smaller than the plate portions, and an arcuate inner surface shape to minimize stress concentration, along with a method of forming the current collector by bending a plate body with a thinner region to prevent acute angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the bent portion is folded to form a compact shape, then the thickness of the current collector is reduced, but stress concentration occurs at the bent portion causing cracks
Solution Approach 1:
The bent portion is formed with a curved shape instead of a sharp fold, creating a smooth transition between plate portions. This curvature eliminates stress concentration points that would occur at acute angles, preventing cracks while maintaining the compact thickness of the current collector.
Solution Approach 2:
The thickness of the curved portion is made smaller than the thickness of the first and second plate portions. This local variation in thickness allows the curved portion to flex without creating stress concentration, while the thicker plate portions maintain structural integrity.
2Volume of moving object
If the current collector is made thin by folding, then the compact shape is achieved, but acute angles form causing stress concentration
Solution Approach 1:
The bent portion is formed with a curved shape instead of a sharp fold, creating a smooth transition between plate portions. This curvature eliminates stress concentration points that would occur at acute angles, preventing cracks while maintaining the compact thickness of the current collector.
Solution Approach 2:
The thickness parameter of the curved portion is changed to be smaller than the thickness of the plate portions. This parameter change allows the curved portion to accommodate bending without forming acute angles, eliminating stress concentration while achieving the desired compact shape.
Data Source
AI summary
An energy storage device, includes a terminal; an electrode assembly having a body portion and a tab portion projecting from the body portion; and a current collector electrically connecting the terminal and the tab portion with each other. The current collector is configured such that a plate portion and a second plate portion which opposedly face each other are continuously formed with each other with curved portion interposed therebetween, and a thickness of the curved portion is set smaller than a thickness of the first plate portion and a thickness of the second plate portion.