Prismatic Battery Tab Layout for Higher Volume Energy Density
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Solution Overview
Problem
Prismatic secondary batteries used in electric vehicles face challenges in achieving high volume energy density due to space requirements for wound electrode core exposed portions and complex current collector structures, limiting their capacity and efficiency.
Innovation Solution
A prismatic secondary battery design featuring a flat-shaped winding electrode body with positive and negative electrode tab portions at one end, perpendicular to the sealing plate, and a simplified current collector structure, allowing for reduced space usage and increased energy density, achieved by integrating terminal and current collector components and optimizing tab portion dimensions and placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wound positive electrode core exposed portion and wound negative electrode core exposed portion are disposed at both ends of the electrode body, then current collection efficiency is improved, but volume energy density deteriorates due to space requirements
Solution Approach 1:
The patent combines both positive and negative electrode tab portions at one end of the wound electrode body, merging functions that were previously separated at opposite ends. This consolidation allows current collectors to be positioned more efficiently and reduces the space required for terminal connections, thereby improving volume energy density while maintaining current collection efficiency through the integrated tab arrangement.
Solution Approach 2:
The patent repositions the tab portions from a longitudinal distribution (at both ends) to a concentrated arrangement at one end, utilizing the width dimension more effectively. By placing tabs at one end and using widthwise spacing, the design optimizes the three-dimensional space utilization within the prismatic battery, reducing the lengthwise space requirement and improving overall volume energy density.
2Reliability
If complex current collector structure is used to accommodate wound electrode cores, then current collection efficiency is improved, but device complexity increases
Solution Approach 1:
The patent simplifies the current collector structure by positioning both positive and negative current collectors at one end of the battery, merging their placement locations. This consolidated arrangement reduces structural complexity compared to having separate current collectors at opposite ends, while maintaining effective current collection through the integrated tab configuration and optimized electrical pathways.
3Volume of stationary object
If tab portions are placed at one end widthwise spaced apart, then volume energy density is improved, but risk of tab contact increases
Solution Approach 1:
The patent applies local quality by creating insulating barriers specifically at the tab portion locations where contact risk exists. The current collectors and their supporting structures are designed with localized insulating features at the end where tabs are concentrated, providing targeted protection against tab contact while maintaining the space-efficient one-end configuration that improves volume energy density.
Data Source
AI summary
A flat-shaped winding electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween includes a positive electrode tab portion and a negative electrode tab portion at one end in a direction in which a winding axis of the winding electrode body extends. Two pieces of the flat-shaped winding electrode body are housed in a prismatic outer body so that the winding axis of each piece is disposed in a direction perpendicular to a sealing plate, and the positive electrode tab portion and the negative electrode tab portion are located on one end of the winding electrode body closer to the sealing plate than the other end.