Cylindrical Battery Case Protrusion for Anode Crack Prevention
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Solution Overview
Problem
Cylindrical batteries with jelly-roll type electrode assemblies experience stress concentration leading to anode cracks due to the step difference caused by the thickness of the cathode, resulting in deformation and potential failure.
Innovation Solution
Incorporating a protrusion part on the inner circumferential surface of the battery case to control the expansion of the electrode assembly, reducing stress concentration on the outermost anode and preventing cracks and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a jelly-roll type electrode assembly with anode outermost structure is used, then the battery can be manufactured with conventional processes, but stress concentration occurs on the outermost anode causing cracks during charging and discharging
Solution Approach 1:
The cathode is designed with extended portions that protrude beyond the anode at specific locations, creating a local structural modification. This local quality change redistributes the stress that would otherwise concentrate on the outermost anode surface, preventing cracks while maintaining the overall jelly-roll structure and manufacturability
Solution Approach 2:
Instead of extending the anode to cover the cathode end (conventional approach), the invention inverts the arrangement by extending the cathode to protrude beyond the anode. This inversion changes which electrode bears the stress concentration, protecting the anode from cracks while maintaining structural integrity
2Quantity of substance
If the cathode thickness is increased to improve capacity, then the energy density is improved, but the step difference increases causing greater stress concentration on the anode
Solution Approach 1:
The cathode extended portions are strategically positioned at locations where stress concentration occurs. This local structural modification compensates for the increased step difference caused by thicker cathodes, distributing the additional stress across extended surfaces rather than concentrating it on the anode, thereby allowing higher capacity without compromising anode strength
Data Source
AI summary
The present disclosure relates to a cylindrical battery, specifically to a cylindrical battery having an electrode assembly and a battery case including an electrode assembly accommodation part, and more specifically to a cylindrical secondary battery having a jelly-roll type electrode assembly with an outer circumferential tab structure and a battery case including a protrusion part provided on at least a portion of an electrode assembly accommodation part.