Composite Current Collector With Thickened Tabs for Direct Welding
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Solution Overview
Problem
Conventional composite current collectors for secondary batteries require an additional welding process, leading to increased manufacturing costs, decreased energy density, and potential welding defects, while also limiting current flow capacity and safety performance.
Innovation Solution
A composite current collector with a specific structure featuring a first metal layer, a second metal layer, and a binding layer, where the tab zones have a greater thickness than the body zones, allowing for direct welding without an indirect process, enhancing conductivity and safety while maintaining high energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an indirect welding process is used to weld tabs to the current collector, then the tabs can be connected to the current collector, but the manufacturing cost increases and energy density decreases due to additional metal foils and process steps
Solution Approach 1:
The patent extracts and eliminates the intermediate metal foil layer from the conventional indirect welding structure. By directly welding tabs to the current collector body zone without additional metal foils, the design simplifies the manufacturing process while maintaining reliable electrical connection, thereby reducing both manufacturing cost and energy density loss.
Solution Approach 2:
Instead of following the conventional indirect welding approach (tab-to-intermediate-foil-to-current-collector), the patent inverts the welding approach by directly connecting tabs to the current collector body zone. This inversion eliminates unnecessary intermediate layers and process steps, achieving both simplified manufacturing and improved electrical conductivity.
2Reliability
If the thickness of the current collector body zone is increased to improve current flow capacity, then the current flow capacity improves, but the energy density decreases and safety performance worsens due to failure in needle penetration tests
Solution Approach 1:
The patent applies local quality by creating a thickness gradient in the current collector: the body zone maintains standard thickness to preserve energy density and pass safety tests, while the tab zone is locally thickened to enhance current flow capacity. This localized thickness differentiation allows each region to optimize its function without compromising overall battery performance.
Solution Approach 2:
The current collector is segmented into distinct functional zones: a body zone for maintaining structural integrity and energy density, and a tab zone for providing enhanced current flow capacity. This segmentation allows independent optimization of each zone's thickness according to its specific functional requirements.
3Reliability
If the tab zone thickness is increased to enhance conductivity, then the current flow capacity improves, but the overall battery thickness increases which may affect safety and energy density
Solution Approach 1:
The patent implements local quality by thickening only the tab zone where enhanced conductivity is needed, while keeping the body zone at standard thickness. This localized thickness increase improves current flow capacity without significantly increasing overall battery thickness, thereby maintaining both safety and energy density.
Data Source
AI summary
A composite current collector includes a first metal layer, a second metal layer, and a first binding layer. The first metal layer includes a first body zone and a first tab zone. The first tab zone is located at an end of the first metal layer. The second metal layer includes a second body zone and a second tab zone. The second tab zone is located at an end of the second metal layer. The first body zone and the second body zone are connected through the first binding layer. The first tab zone has a thickness greater than thickness of the first body zone. The first tab zone extends toward the second tab zone.