Electrode Plate Layout for Nonuniform Lithium Replenishment Control
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Solution Overview
Problem
Lithium-ion batteries using silicon negative electrodes face issues with low initial coulombic efficiency and uneven lithium replenishment, leading to lithium precipitation, capacity loss, or insufficient lifespan improvement due to varying active material distribution regions.
Innovation Solution
The electrode plate design includes lithium replenishing spaces with varying internal volumes and depths to accommodate lithium replenishing agents, ensuring precise and quantitative lithium replenishment by controlling the distribution of active material weights and volumes in different regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform lithium replenishment is applied across the electrode plate, then the manufacturing process is simple, but lithium precipitation occurs in thinned regions or capacity loss occurs in large regions
Solution Approach 1:
The patent applies local quality by varying the internal volumes of lithium replenishing spaces according to different distribution regions. The current collection structure includes multiple lithium replenishing spaces with different volumes, where spaces in regions with lower active material density have smaller volumes, and spaces in regions with higher active material density have larger volumes. This localized adaptation ensures precise lithium replenishment matching the specific needs of each region, avoiding both lithium precipitation and capacity loss.
2Manufacturing precision
If lithium replenishing spaces with varying volumes are used, then precise lithium replenishment is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the lithium replenishing spaces directly into the current collection structure, making the current collection structure an integrated component that both collects current and provides lithium replenishment functionality. This integration eliminates the need for separate replenishment mechanisms and simplifies the overall device structure while maintaining precise lithium replenishment capabilities through the varied volumes of the embedded spaces.
3Quantity of substance
If silicon negative electrodes are used to increase energy density, then the battery capacity increases, but the initial coulombic efficiency decreases
Solution Approach 1:
The patent applies preliminary action by pre-filling lithium replenishing spaces with lithium replenishing agents before battery operation. These agents serve as a reserved lithium source that can be released during cycling to compensate for irreversible lithium consumption. This preliminary preparation ensures that lithium is available to maintain coulombic efficiency when silicon negative electrodes are used, without requiring post-manufacturing adjustments.
Data Source
AI summary
Lithium replenishing spaces are disposed on a current collection structure, such that the lithium replenishing spaces communicate with an active layer on one side; and the battery is replenished with lithium by using lithium replenishing agents in the lithium replenishing spaces to offset an irreversible lithium consumption in a cycle process, so as to increase the total capacity and the energy density of the battery. According to the present application, due to average weights MA of corresponding active materials in different distribution regions on the active layer, a sum V0 of internal volumes of lithium replenishing spaces corresponding to each of the distribution regions is controlled in a positively correlated manner based on a change in the average weights of the active materials in the different distribution regions.