Cathode Plate Cutouts Prevent Lithium Evolution
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Solution Overview
Problem
Lithium-ion batteries face safety concerns due to lithium evolution and capacity attenuation caused by misalignment between the current collector and active material layer during the curing process, leading to indentation formation.
Innovation Solution
A cathode plate design with cutouts or barrier layers at the ends of the active material layers to prevent lithium evolution, combined with an anode plate having an indentation at the margin area, which corresponds to the cutouts or barrier layers, thereby avoiding lithium evolution and increasing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the active material layer is coated on the current collector using a gap coating process, then the coating process is simple and efficient, but the misalignment between the current collector and the end of the active material layer causes indentation formation during curing
Solution Approach 1:
The patent applies preliminary action by pre-forming cutouts at the ends of the current collector before coating the active material layer. These cutouts are positioned in advance to match where the active material layer ends, so when the layer is coated and cured, the cutouts prevent the slurry from shrinking into indentations at the edges. This preliminary structural preparation resolves the alignment issue without compromising coating efficiency.
Solution Approach 2:
The patent applies local quality by modifying only the end regions of the current collector with cutouts, rather than changing the entire structure. The cutouts are localized at specific positions where indentation problems occur, allowing the majority of the current collector to maintain its standard structure and coating process, thus preserving overall manufacturing efficiency while solving the local alignment precision issue.
2Ease of manufacture
If the active material layer shrinks during curing to form an indentation, then the coating process is complete, but lithium evolution risk increases and battery capacity attenuates
Solution Approach 1:
The patent applies preliminary anti-action by introducing cutouts at the ends of the current collector that preemptively counteract the shrinking force of the active material layer during curing. The cutouts create a physical barrier and stress relief zone that prevents the slurry from forming indentations, thereby eliminating the condition that leads to lithium evolution. This preliminary protective structure maintains curing completion while preventing safety issues.
3Manufacturing precision
If the current collector and active material layer are perfectly aligned, then indentation is prevented, but the coating process becomes more complex and time-consuming
Solution Approach 1:
Instead of improving alignment precision during the coating process, the patent uses preliminary action by pre-forming cutouts on the current collector. This shifts the solution from the coating alignment step to a prior preparation step, maintaining simple coating processes while achieving precise effective alignment where the active material layer contacts the current collector.
Data Source
AI summary
A cathode plate including a first winding end and a second winding end along a length direction. The cathode plate further includes a cathode current collector and a first cathode active layer. The first cathode active layer is arranged at a surface of the cathode current collector, and the first cathode active layer includes a first end portion located at the first winding end, and the first end portion has a first cutout or a first barrier layer provided at a margin area. This application further provides an electrode assembly including the cathode plate.