Battery Electrode Assembly With Bent Flag Tabs for Better Welding
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Solution Overview
Problem
Conventional cylindrical battery cells with strip-shaped electrode tabs exhibit high resistance, heat generation, and poor current collection efficiency due to current concentration, and tab-less designs face challenges in ensuring proper contact and welding quality between uncoated portions and current collector plates, leading to increased defect rates.
Innovation Solution
The electrode assembly features a first and second electrode with uncoated portions that include flag portions with inner and outer bent regions, allowing for improved contact efficiency and welding quality by alternating bends and multiple contact points with a current collector plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a strip-shaped electrode tab is used to connect uncoated portions to terminals, then the battery cell structure is simple, but current concentration causes high resistance, high heat generation, and poor current collection efficiency
Solution Approach 1:
The uncoated portion is segmented into multiple regions: a main uncoated portion and multiple divided uncoated portions extending in the winding direction. This segmentation distributes current collection across multiple contact points with the current collector plate, eliminating current concentration at a single strip-shaped tab while maintaining structural simplicity.
2Area of stationary object
If the uncoated portion is bent to increase welding area, then contact area with current collector plate increases, but visual confirmation of welded portion becomes difficult and contact efficiency deteriorates
Solution Approach 1:
Instead of bending the uncoated portion in a single direction to increase area, the invention extends divided uncoated portions in the winding direction (another dimension). This creates multiple contact points along the length of the electrode assembly, achieving increased welding area while maintaining flat, visually inspectable configuration that ensures proper contact alignment.
3Area of stationary object
If uncoated portions are bent for welding, then welding area increases, but contact efficiency between uncoated portion and current collector plate deteriorates
Solution Approach 1:
The uncoated portion is divided into multiple segments extending in the winding direction, creating multiple contact points. This segmentation maintains flat configuration for reliable contact while distributing the welding area across multiple locations, achieving both increased welding area and maintained contact efficiency.
4Productivity
If welding is performed without proper contact between bent uncoated portion and current collector plate, then manufacturing process is simple, but welding quality deteriorates and defect rate increases
Solution Approach 1:
The divided uncoated portions are pre-configured to extend in the winding direction before welding, establishing multiple contact points with the current collector plate in advance. This preliminary arrangement ensures proper contact alignment is achieved by design rather than requiring complex adjustment during welding, maintaining manufacturing speed while ensuring welding quality.
Data Source
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AI summary
The present disclosure relates to an electronic assembly including a first electrode including a first uncoated portion, a first flag portion formed by extending a part of the first uncoated portion, and a first extension portion connecting the first uncoated portion and the first flag portion, a second electrode, and a separator arranged between the first electrode and the second electrode, wherein the first electrode, the second electrode, and the separator are wound in a form of a roll around a virtual winding center, and wherein the first flag portion comprises at least one inner bent region bent in the winding center direction and at least one outer bent region bent in an opposite direction to the winding center direction.