Partitioned Electrode Regions for Lithium Dendrite Prevention
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Solution Overview
Problem
Lithium-ion batteries face safety issues due to the formation of lithium dendrites during long-term charge-discharge cycles, leading to electrochemical short circuits, which is not effectively addressed by existing technologies.
Innovation Solution
The solution involves partitioning the anode and cathode into regions with varying direct current resistance values, particle diameters, and active material compositions to manage lithium deposition, thereby reducing the likelihood of lithium dendrite formation and enhancing safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-ion batteries undergo long-term charge-discharge cycles, then energy storage capacity is maintained, but lithium dendrites form on the electrode surface leading to safety issues
Solution Approach 1:
The electrode is divided into multiple regions with different active material compositions and particle size distributions. The edge region contains finer particles and different material composition compared to the body region, creating heterogeneous structure that prevents uniform lithium deposition and reduces dendrite formation risk while maintaining overall battery safety.
Solution Approach 2:
Different regions of the electrode are assigned different local properties: the edge region has smaller particle diameter and different active material composition compared to the body region. This local quality variation optimizes lithium ion insertion/extraction kinetics at different locations, preventing lithium dendrite formation at vulnerable edge areas while maintaining high capacity in the body region.
2Ease of manufacture
If electrode structure is made uniform, then manufacturing is simplified, but lithium deposition becomes uneven leading to dendrite formation
Solution Approach 1:
The electrode manufacturing process is segmented into different coating formulations for body and edge regions. By preparing separate slurries with different active material compositions and particle size distributions, the patent achieves precise control over lithium deposition patterns while maintaining a systematic manufacturing approach that is scalable.
Solution Approach 2:
The patent implements local quality variation in the electrode structure by coating different active material compositions in different regions. The edge region receives coating with smaller particle diameter and different composition ratios, while the body region receives coating with larger particle diameter. This localized differentiation ensures uniform lithium deposition across the entire electrode surface.
Data Source
AI summary
A lithium secondary battery is disclosed which includes a cathode having a first cathode region and a second cathode region adjacent to the first cathode region, wherein the second cathode region is adjacent to an uncoated region of the cathode substrate; an anode, the anode having a first anode region and a second anode region adjacent to the first anode region, wherein the second anode region is adjacent to an uncoated region of the anode substrate, wherein a value C1 is a ratio of a direct current resistance value RA1 of the first anode region to a direct current resistance value RC1 of the first cathode region; wherein a value C2 is a ratio of a direct current resistance value RA2 of the second anode region to a direct current resistance value RC2 of the second cathode region; and wherein C2<C1.