Segmented Electrode Assembly for Low-Resistance Cylindrical Batteries
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Solution Overview
Problem
Conventional cylindrical batteries face issues with high resistance and heat generation due to concentrated current flow at the electrode tab, leading to potential ignition during rapid charging, and poor electrolyte impregnation and process efficiency due to uncoated portions being bent and blocking the electrolyte injection path.
Innovation Solution
The electrode assembly features a segmented uncoated portion structure with independently bendable segments, allowing for improved electrolyte impregnation, reduced resistance, and efficient welding by applying a current collecting plate to the bending surface region, with a design that prevents internal short circuits and allows easy electrical wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If current is concentrated in the strip-shaped electrode tab, then the battery structure is simple, but the current collection efficiency is poor due to large resistance and large heat generation
Solution Approach 1:
The electrode tab is divided into multiple segments (first electrode tab, second electrode tab, third electrode tab, fourth electrode tab) arranged in a circular pattern around the core. This segmentation distributes the current collection points, reducing resistance and heat generation at each individual tab while maintaining structural simplicity.
2Reliability
If the uncoated portion is bent to improve welding, then the current collection efficiency is improved, but the electrolyte injection path is blocked causing poor electrolyte impregnation
Solution Approach 1:
The uncoated portion is divided into multiple segments that are bent toward the core, creating a radial arrangement. This segmentation allows the bent segments to form a compact structure that maintains good electrical contact for welding while leaving sufficient space between segments for electrolyte injection and impregnation.
Solution Approach 2:
The uncoated portions are bent from a flat planar configuration into a three-dimensional radial arrangement around the core. This dimensional transformation improves welding contact in the radial direction while maintaining adequate spacing in the axial direction for electrolyte flow.
3Area of stationary object
If the uncoated portion is bent toward the core, then the welding surface area is increased, but the uncoated portion deforms and blocks the electrolyte injection path
Solution Approach 1:
Dividing the uncoated portion into multiple small segments reduces the deformation stress on each individual segment compared to bending a large continuous uncoated portion. The segmented structure allows controlled bending with improved welding surface area while minimizing harmful deformation and blocking effects.
Data Source
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AI summary
Disclosed is an electrode assembly, a battery, and a battery pack and a vehicle including the same. In the electrode assembly, the uncoated portion of an electrode includes a segment region divided into a plurality of segments, and the segment region includes a plurality of segment groups divided by a group separation pitch along a winding direction. One end of the electrode assembly includes a plurality of segment alignments. In winding turns corresponding to the plurality of segment alignments, group separation pitches of segment groups disposed in the same winding turn are substantially identical, and the separation pitch of the segment groups is greater in a winding turn of a region adjacent to the outer circumference than in a winding turn of a region adjacent to the core.