Electrode Tab Buffer Tape for Crack-Resistant Battery Assemblies
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Solution Overview
Problem
Rechargeable batteries, particularly wound-type batteries, are prone to cracks due to the rigidity of the electrode tab and expansion during charging and discharging, especially when the curvature is small, leading to potential damage.
Innovation Solution
An electrode assembly design with a substrate, an electrode tab, an active material layer, and a tape disposed between the substrate and the electrode tab, where the tape overlaps a portion of the uncoated region, reducing the step and preventing cracks by absorbing pressure from burrs and maintaining a gap with the active material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the electrode tab is made rigid to maintain structural stability, then the structural stability is improved, but cracks occur more easily around the electrode tab due to small curvature and expansion during charge and discharge
Solution Approach 1:
A buffer layer is introduced between the rigid electrode tab and the electrode substrate to mediate the mechanical stress. This intermediary layer absorbs expansion forces during charge and discharge, preventing direct transmission of stress to the tab-substrate interface and reducing crack formation while maintaining structural stability.
Solution Approach 2:
The physical and chemical parameters of the buffer layer are optimized to match the electrode substrate while providing different mechanical properties. The buffer layer has intermediate stiffness between the rigid tab and flexible substrate, creating a gradient structure that reduces stress concentration and prevents cracking.
2Device complexity
If the electrode tab is attached directly to the electrode substrate to simplify structure, then the device complexity is reduced, but cracks occur due to the rigidity mismatch and expansion pressure
Solution Approach 1:
The buffer layer serves as a mediating component between the electrode tab and substrate. While it adds one layer to the structure, it significantly improves reliability by absorbing mechanical stress and preventing cracks, making the overall design more robust despite the slight increase in complexity.
Solution Approach 2:
The buffer layer is positioned in advance at the interface between the electrode tab and substrate to provide cushioning before expansion occurs. This pre-positioned protective layer absorbs expansion pressures during charge and discharge cycles, preventing crack formation at the vulnerable interface.
3Quantity of substance
If the electrode assembly is designed with small curvature to increase energy density, then the energy density is improved, but cracks occur more easily due to the rigidity of the electrode tab
Solution Approach 1:
The buffer layer acts as a stress-absorbing intermediary that enables small curvature designs. By mediating the mechanical stresses at the tab-substrate interface, it allows the electrode assembly to be compacted with smaller curvature to increase energy density without suffering from crack-related reliability issues.
Solution Approach 2:
The mechanical parameters of the buffer layer are specifically designed to accommodate small curvature configurations. The layer's intermediate stiffness and compliance allow it to flex with the curved geometry while protecting the rigid electrode tab from stress concentration, enabling high energy density designs.
Data Source
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AI summary
An electrode for a rechargeable battery is provided. The electrode includes a substrate having an electrode uncoated region and an electrode active region. An electrode tab is attached to the electrode uncoated region, and an active material layer is formed on the electrode active region. A tape is disposed between the electrode uncoated region and the electrode tab.