Cylindrical Battery Electrode Bending for Stronger Collector Welding
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Solution Overview
Problem
Cylindrical secondary batteries face issues with increased internal resistance due to reduced weldable substrates and increased distance between them, leading to decreased heat capacity and potential melting of electrode plates during welding, which affects the current collecting structure.
Innovation Solution
A manufacturing method that involves pre-compacting the electrode uncoated portions using jigs to ensure uniform and regular overlapping during welding, enhancing the strength of current collector welding and reducing dispersion, thereby improving the current collecting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity of cylindrical secondary battery increases, then the battery capacity increases, but the amount of weldable substrates decreases and the distance between substrates increases
Solution Approach 1:
The substrate is pre-compacted before welding to increase the overlapping amount of weldable portions. This preliminary action ensures that when the battery capacity increases and substrates are farther apart, there is still sufficient overlapping area for effective welding, thus resolving the contradiction between increased capacity and reduced weldable substrate area.
2Quantity of substance
If the distance between substrates increases, then the battery capacity increases, but the heat capacity of the welded portion decreases
Solution Approach 1:
The substrate is pre-compacted to increase the overlapping amount before welding. This ensures that even when substrates are farther apart (higher capacity), the welded portion has sufficient material overlap to maintain adequate heat capacity and welding strength.
3Ease of manufacture
If welding is performed after substrate compaction, then the battery assembly is completed, but empty space is generated and welding heat penetrates causing electrode plate or separator melting
Solution Approach 1:
The substrate is pre-compacted to eliminate empty spaces before welding. This preliminary densification ensures that when welding is performed, there are no voids to allow welding heat to penetrate and cause melting of the electrode plate or separator, thus preventing the harmful effects while maintaining manufacturing feasibility.
4Ease of manufacture
If substrates are not uniformly overlapped during welding, then the welding process is simpler, but the welding strength is reduced and welding dispersion increases
Solution Approach 1:
The substrate is pre-compacted using a compaction device that applies uniform pressure across the substrate width. This preliminary uniform compaction ensures that when welding is performed, the substrates are uniformly overlapped, resulting in consistent welding strength and reduced welding dispersion, while the welding process itself remains relatively simple.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method increases the overlapping amount of substrates, enhances the tensile strength of current collector welding, and improves resistance distribution and welding quality, resulting in a more efficient current collecting structure.
Implementation Method 1
bending at least some portions of the first electrode uncoated portion and the second electrode uncoated portion of the electrode assembly in a direction by pressing the first electrode uncoated portion and the second electrode uncoated portion
Implementation Method 2
welding electrode collector plates to ends of the bent first and second electrode uncoated portions
Data Source
AI summary
A cylindrical secondary battery and a manufacturing method of a secondary battery are provided. A manufacturing method of a cylindrical secondary battery includes: winding an electrode assembly to expose a first electrode uncoated portion and a second electrode uncoated portion to opposite ends in a longitudinal direction; bending at least some portions of the first electrode uncoated portion and the second electrode uncoated portion of the electrode assembly in a direction by pressing the first electrode uncoated portion and the second electrode uncoated portion; welding electrode collector plates to ends of the bent first and second electrode uncoated portions; and inserting and sealing the electrode assembly into a cylindrical case.