Partitioned Electrode Design for Lithium Dendrite Prevention
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Solution Overview
Problem
Lithium ion batteries face safety issues due to the formation of lithium dendrites on the anode surface during long-term charge and discharge cycles, leading to electrochemical short circuits and reduced safety.
Innovation Solution
The battery cell is designed with partitioned anode and cathode regions, where the unit area capacities are adjusted to prevent uneven lithium deposition, with the anode thin region having a capacity equal to or greater than the body region and the cathode thin region having a capacity less than or equal to 98% of the body region, reducing the likelihood of lithium dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode and cathode have uniform thickness and capacity distribution, then the manufacturing process is simple, but lithium dendrites form on the anode surface during long-term charge and discharge cycles
Solution Approach 1:
The anode and cathode are divided into different regions (body region and thin region) with different capacities. The anode thin region has a capacity greater than or equal to the body region, while the cathode thin region has a capacity less than or equal to 98% of the body region. This segmentation creates a capacity gradient that prevents uneven lithium deposition and dendrite formation.
Solution Approach 2:
Different regions of the electrode are designed with different local properties. The anode thin region is designed with higher capacity than the body region to compensate for the reduced thickness, while the cathode thin region has lower capacity. This local quality variation ensures uniform lithium distribution across different electrode regions.
2Reliability
If the anode thin region has lower capacity than the body region, then the manufacturing process is simpler, but lithium deposits unevenly causing dendrite formation
Solution Approach 1:
The capacity parameters of different electrode regions are specifically adjusted. The anode thin region capacity is set to be greater than or equal to the body region capacity, while the cathode thin region capacity is set to be less than or equal to 98% of the body region capacity. These parameter changes create a balanced capacity distribution that prevents lithium deposition issues.
3Reliability
If the cathode thin region has capacity equal to or greater than the body region, then manufacturing is easier, but lithium dendrites form due to excess lithium ions
Solution Approach 1:
The cathode is segmented into body region and thin region with different capacity characteristics. The thin region capacity is specifically designed to be less than or equal to 98% of the body region capacity, creating a capacity gradient that matches the anode's lithium absorption capacity and prevents excess lithium ion deposition.
Data Source
AI summary
A battery cell is disclosed having a cathode including a cathode substrate with a surface coating of a first cathode active material in a first cathode region and a second cathode active material in a second cathode region, an anode including an anode substrate having a surface coating of a first anode active material in a first anode region and a second anode active material in a second anode region, wherein a value CB1 is a ratio of a unit area capacity CsA1 of the first anode region to a unit area capacity Csc1 of the first cathode region, a value CB2 is a ratio of a unit area capacity CsA2 of the second anode region to a unit area capacity Csc2 of the second cathode region, wherein the surface coating of the cathode and/or anode is a partitioned coating including different active materials, and wherein CB2≥CB1.