Cylindrical Battery Terminal Layout for Low-Resistance Current Paths
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Solution Overview
Problem
Secondary batteries face challenges in achieving low electrical resistance and accommodating large electrode assemblies within a compact case while maintaining terminal flatness and efficient current paths.
Innovation Solution
The design includes first and second tabs of the electrode assembly aligned in the same direction for electrical connection to terminals, with three-dimensionally coupled current collector plates occupying a small volume and a conductive ring plate on the terminal for flatness, enhancing electrical conductivity and assembly accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If tabs are arranged in opposite directions for electrical connection, then terminal connection is simplified, but current path length increases and electrical resistance increases
Solution Approach 1:
The patent transitions from traditional opposite-direction tab arrangement to same-direction tab arrangement, utilizing three-dimensional spatial configuration. Both tabs protrude in the same direction (first direction) from the electrode assembly, allowing current collectors to connect them in a compact three-dimensional structure rather than extending in opposite directions, thereby shortening the current path while maintaining connection simplicity
Solution Approach 2:
The current collectors are configured to wrap around and connect both tabs in a nested manner. The first current collector connects the first tab to the first terminal, while the second current collector connects the second tab to the second terminal, with both current collectors positioned in the same region and occupying minimal space through three-dimensional coupling, effectively nesting the electrical connection components
2Reliability
If current collector plates are extended to connect tabs in opposite directions, then electrical connection is achieved, but volume occupied increases and case size increases
Solution Approach 1:
The current collectors utilize three-dimensional spatial arrangement instead of extended planar connections. Both current collectors are positioned in substantially the same region and coupled in the third dimension (thickness direction), allowing them to connect tabs in the same direction while occupying minimal volume within the case
Solution Approach 2:
The patent merges the spatial regions of both current collectors, positioning them in substantially the same region rather than extending them in opposite directions. This consolidation of spatial occupation reduces the overall volume required for electrical connections, allowing for a more compact case design
3Ease of manufacture
If terminals are connected without additional flatness structures, then assembly is simpler, but terminal flatness is poor and contact reliability decreases
Solution Approach 1:
A conductive ring plate is introduced as an intermediary component between the second terminal (case) and the external connection. This ring plate provides a flat contact surface that ensures reliable electrical connection and improves terminal flatness, while the conductive material maintains low electrical resistance. The ring plate is positioned at the periphery of the rivet terminal where it contacts the case
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A secondary battery includes a case having a cylindrical shape, an electrode assembly in the case, and including a first tab protruding in a first direction at a center portion, and a second tab protruding in the first direction at a perimeter, a first current collector plate in the case and electrically connected to the first tab, a second current collector plate electrically connecting the second tab to the case, and a rivet terminal electrically connected to the first current collector plate, and passing through the case.