Rectangular Battery Tab Group Design for Volumetric Density
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Solution Overview
Problem
Rectangular secondary batteries used in electric vehicles face challenges in increasing volumetric energy density due to the space requirements for electrode core exposed portions, which limits their capacity and efficiency.
Innovation Solution
The design incorporates a tab group system where multiple tabs are connected to current collectors and positioned between the electrode body and the sealing plate, allowing for reduced space between these components, along with a short-circuit mechanism to prevent overcharging, thereby enhancing volumetric energy density and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode body has exposed portions at both ends for terminal attachment, then the terminals can be attached to the electrode body, but the battery case requires left and right spaces that reduce the volumetric energy density
Solution Approach 1:
The patent changes the spatial arrangement of exposed portions from horizontal (both ends of the electrode body) to vertical (one end only, at the upper side). This dimensional repositioning allows terminals to be attached at the same end while eliminating the need for left and right spaces in the battery case, thereby increasing volumetric energy density while maintaining terminal attachment reliability
2Volume of stationary object
If the electrode body has exposed portions at one end only, then the volumetric energy density increases, but the terminal attachment structure becomes more complex requiring tab groups and current collectors
Solution Approach 1:
The patent segments the terminal attachment structure into distinct functional components: tabs extending from the electrode body, tab groups formed by bundling multiple tabs, and current collectors that connect to the tab groups. This segmentation allows the complex terminal attachment function to be distributed across multiple simple components, making the overall structure more manageable and manufacturable while achieving high volumetric energy density
3Volume of stationary object
If multiple tabs are connected to current collectors and disposed between the electrode body and sealing plate, then the space between electrode body and sealing plate is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The patent performs preliminary actions by pre-forming tabs on the electrode body, pre-bundling them into tab groups, and pre-attaching current collectors to the tab groups before final assembly into the battery case. This preliminary preparation of components simplifies the overall manufacturing process by breaking down the complex assembly into manageable pre-assembled units, while still achieving reduced space between the electrode body and sealing plate
Data Source
AI summary
An electrode body is disposed in a rectangular casing having an opening, and the opening of the rectangular casing is sealed by a sealing plate. A positive-electrode current collector is connected to a positive electrode terminal that extends through the sealing plate. A first positive-electrode tab group and the second positive-electrode tab group, which are connected to the electrode body, is connected to a surface of the positive-electrode current collector facing the electrode body. The first positive-electrode tab group and the second positive-electrode tab group are each disposed at an end portion of the electrode body adjacent to the sealing plate, and the first positive-electrode tab group and the second positive-electrode tab group are disposed so as to be bent in different directions.