Battery Collector Foil Stacking for Volume Energy Density
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Solution Overview
Problem
Batteries for electric vehicles require increased capacity with limited installation space, necessitating a high volume energy density, which is hindered by dead space in the battery case.
Innovation Solution
A compact collector structure for the electrode body is achieved by alternately stacking positive and negative electrode sheets with separators, where collector foils protrude beyond the separators, forming a stack that is bent around a base end, reducing dead space and allowing for a more efficient internal terminal configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery capacity is increased to enable longer vehicle travel, then the energy storage capability is improved, but the volume energy density decreases due to increased dead space in the battery case
Solution Approach 1:
The collector foils are extended in the stacking direction beyond the separators, and the protruded portions are bent in a direction substantially perpendicular to the stacking direction. This dimensional change allows the collector structure to occupy space more efficiently in three dimensions, reducing dead space and improving volume energy density while maintaining battery capacity.
Solution Approach 2:
The protruded portions of the collector foils are bent into a curved configuration around a base end, rather than extending linearly. This curvature allows the collector structure to compactly fit within the battery case, minimizing dead space and improving volume energy density while still providing adequate electrical connection.
2Ease of manufacture
If a conventional collector structure is used, then the manufacturing process is simple, but dead space increases reducing volume energy density
Solution Approach 1:
The collector structure is divided into distinct segments: the collector foils within the electrode body, the protruded portions extending beyond the separators, and the bent portions forming the internal terminal. This segmentation allows each part to be optimized independently - the protruded portions can be extended to reduce dead space while the bent portions provide compact termination, improving volume energy density without significantly complicating manufacturing.
Data Source
AI summary
A battery includes an electrode body and an internal terminal attached to the electrode body. The electrode body includes positive electrode sheets, negative electrode sheets, and separators. The positive electrode sheets and the negative electrode sheets are alternately stacked in a stacking direction, with each separator interposed between associated adjacent ones of the positive electrode sheets and the negative electrode sheets. The positive electrode sheets and the negative electrode sheets each include a collector foil. At least either portions of the collector foils of the positive electrode sheets or the negative electrode sheets are protruded beyond the separators in one direction. The protruded portions of the collector foils are piled in a stack in the stacking direction. The internal terminal includes a connector connected to the stack of the protruded portions of the collector foils. The stack of the protruded portions is bent around a base end of the protruded portions of the collector foils.