Pouch Battery Electrode Assembly Taping for Side Reaction Suppression
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Solution Overview
Problem
Pouch-type secondary batteries experience side reactions at the end portions where electrode tabs are connected during the charging and discharging process due to electrolyte accumulation, which can be exacerbated by reduced thickness in inclined areas.
Innovation Solution
The implementation of tapes, made of insulating or pressure-resistant materials, at the inclined areas where electrode tabs are located, along with a modified press device structure, to improve flatness and prevent electrolyte accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode assembly is pressed during the HPC process, then electrical characteristics are improved, but electrolyte accumulates at the end portions causing side reactions
Solution Approach 1:
The patent applies different pressing forces to different regions of the electrode assembly. Specifically, the pressing device exerts reduced pressing force on the end portions (first and second end portions) compared to the central portions, where the electrode tabs are located. This local differentiation prevents electrolyte accumulation and side reactions at the end portions while still achieving adequate electrical characteristics through pressing of the main body of the electrode assembly.
2Shape
If the electrode mixture portion thickness is reduced in inclined areas, then the battery structure is optimized, but electrolyte accumulation increases at the end portions
Solution Approach 1:
The patent identifies that the inclined areas at the end portions have reduced thickness of the electrode mixture portion, which creates a geometric feature that promotes electrolyte accumulation. The pressing device is designed to apply reduced pressing force specifically to these end portions with inclined areas, compensating for the thickness reduction and preventing electrolyte accumulation in these vulnerable regions while maintaining the optimized thin structure where it benefits performance.
Data Source
AI summary
A pouch-type secondary battery includes: an electrode assembly including a stack of unit cells including: a first electrode plate; a first electrode tab on the first electrode plate; a second electrode plate; a second electrode tab on the second electrode plate; and a separator between the first electrode plate and the second electrode plate; and a first tape attached to a front side of the electrode assembly perpendicular to a stacking direction of the stack of unit cells. The first tape is located at a corner portion of the electrode assembly where the first electrode tab or the second electrode tab is located, and the corner portion is located at an inclined area where a thickness of the electrode assembly decreases.