Secondary Battery Tab Assembly With Gathered Straight Electrode Tabs
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Solution Overview
Problem
Existing secondary batteries face issues with cell stability due to electrode plate tearing and base material tab breakage during repeated charging and discharging, necessitating a solution to enhance structural integrity and capacity.
Innovation Solution
The electrode assembly design includes first and second base material tabs that protrude from electrode plates, gathered and coupled at the upper end of the assembly without bending, with a length of 1.7 mm or less, and are butt-welded to a lead tab, minimizing the bent area and secured by an insulating tape, housed in a pouch with an accommodation groove to maintain electrical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If base material tabs are made longer to facilitate coupling, then ease of manufacture is improved, but reliability deteriorates due to increased bending and breakage risk
Solution Approach 1:
The patent transitions from a planar tab arrangement to a three-dimensional gathered configuration where multiple tabs are stacked and coupled together at a single location. This dimensional change allows the tabs to be coupled without requiring long protruding lengths, as they are brought together in the thickness direction (Y-axis) of the electrode assembly. The coupling point is positioned at the upper end of the electrode assembly where tabs from multiple electrode plates converge, enabling secure connection with minimal protrusion length (1.7 mm or less).
Solution Approach 2:
Multiple base material tabs from different electrode plates are gathered and merged into a single coupled structure at the upper end of the electrode assembly. This merging of multiple tabs into one consolidated connection point eliminates the need for each tab to individually extend long distances, while simultaneously providing structural reinforcement through the combined strength of multiple tabs working together as a unified electrical connection.
2Productivity
If electrode assembly thickness is reduced to increase energy density, then productivity is improved, but manufacturing precision deteriorates due to tighter tolerances
Solution Approach 1:
The electrode assembly is segmented into discrete electrode plates (first and second electrode plates) with dedicated base material tabs protruding from each plate. This segmentation allows each tab to be independently positioned and coupled, providing built-in alignment features that maintain manufacturing precision even in thinner assemblies. The segmented structure with multiple stacked tabs creates natural spacing and positioning references that reduce tolerance accumulation throughout the assembly process.
3Ease of manufacture
If base material tabs are bent to achieve coupling, then ease of manufacture is improved, but strength deteriorates due to bending stress and potential tearing
Solution Approach 1:
Instead of bending the tabs to achieve coupling, the patent inverts the approach by making the tabs rigid and straight, and achieving coupling through their gathered arrangement in the thickness direction. The coupling is accomplished by positioning the straight tabs at the upper end of the electrode assembly and connecting them without requiring any bending deformation. This inversion eliminates the creation of stress concentration points that would otherwise occur at bent tab regions.
Solution Approach 2:
The patent converts what would traditionally be a manufacturing challenge (the need for precise tab positioning and alignment) into a benefit by utilizing the natural protrusion of straight tabs from the electrode plates. The slight protrusion length (1.7 mm or less) that might be considered excessive is actually beneficial as it provides sufficient coupling length while maintaining tab straightness, and the gathered configuration of multiple tabs provides redundant structural support that compensates for any minor positioning variations.
Data Source
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AI summary
Provided is a secondary battery capable of increasing in capacity by reducing a length of a bent area of an electrode tab. The secondary battery including an electrode assembly, which includes a plurality of first electrode plates coated with a first active material, a plurality of second electrode plates coated with a second active material, and a separator disposed between each of the first electrode plates and each of the second electrode plates, includes a plurality of first base material tabs protruding from the plurality of first electrode plates, respectively, and a plurality of second base material tabs protruding from the plurality of second electrode plates, respectively. Each of the plurality of first base material tabs and each of the plurality of second base material tabs are gathered to one end of the electrode assembly in a thickness direction of the electrode assembly and are coupled to each other.