Lithium-Ion Battery Electrode Zoning for Grooved Cathode Cycling
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Solution Overview
Problem
The combination of a cathode active material layer with a groove portion and a silicon-based anode active material layer in lithium-ion batteries leads to deterioration of cycle characteristics, and increasing energy density requires improved manufacturing designs for electrodes.
Innovation Solution
The lithium-ion battery design includes a cathode with a cathode active material layer having a flat portion and a groove portion, where the anode active material layer differs between these portions, with the first portion containing silicon and the second portion containing graphite or lithium titanate, to manage lithium ion diffusion and improve cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a groove portion is provided in the cathode active material layer to reduce impregnation time, then the impregnation time is reduced, but cycle characteristics deteriorate when combined with Si-based anode active material
Solution Approach 1:
The anode active material layer is designed with different materials in different regions: Si-based material in the first portion facing the flat portion of the cathode, and graphite or lithium titanate in the second portion facing the groove portion. This local differentiation allows the groove portion to maintain fast impregnation while the Si-based portion maintains good cycle characteristics.
Solution Approach 2:
The anode active material layer is segmented into two distinct portions with different functionalities. The first portion (with Si-based material) handles high capacity storage, while the second portion (with graphite or lithium titanate) handles lithium ion diffusion buffering, particularly in the region facing the groove portion where impregnation occurs.
2Reliability
If the anode active material layer is designed with different materials in different portions to improve cycle characteristics, then the device complexity increases
Solution Approach 1:
The anode active material layer is divided into two portions based on their functional requirements. This segmentation is achieved through a simple coating process where different pastes are applied to different regions, maintaining manufacturing simplicity while achieving the desired functional differentiation.
Solution Approach 2:
Different anode materials are placed in specific locations: Si-based material in the first portion for high capacity, and graphite or lithium titanate in the second portion for stable lithium ion diffusion. This local quality assignment optimizes performance without requiring complex multi-layer structures throughout the entire anode.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces the potential difference between the anode portions, slows down lithium ion diffusion, and thereby improves the cycle characteristics of the lithium-ion battery, while also potentially reducing short-circuit failures.
Implementation Method 1
Increase in the potential difference can promote diffusion of lithium (Li) ions from the first portion to the second portion. It is thought that the greatness of the amount of Li ions diffused from the first portion to the second portion is what contributes to deterioration in cycle characteristics.
Data Source
AI summary
The lithium-ion battery includes a cathode, an anode, and an electrolytic solution. The cathode includes a cathode active material layer. The cathode includes a flat portion and a groove portion. A thickness of the cathode active material layer in the groove portion is smaller than a thickness of the cathode active material layer in the flat portion. The anode includes an anode active material layer. The anode active material layer includes a first portion and a second portion. The first portion faces the flat portion. The second portion faces the groove portion. The anode active material layer includes an anode active material. In the first portion, the anode active material contains silicon. In the second portion, the anode active material is at least one type selected from a group consisting of graphite and lithium titanate.