Electrode Assembly Composition for Tab-Adjacent Lithium Precipitation
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Solution Overview
Problem
Excess current flow in the negative electrode plate adjacent to the electrode tab in secondary batteries leads to lithium precipitation, affecting battery life and performance.
Innovation Solution
The electrode assembly features a second active material layer with a higher ratio of conductive additive and a smaller area compared to the main active material layer, along with a distinct conductive additive composition, to manage current distribution and reduce lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform active material layer is used across the entire electrode plate, then the manufacturing process is simple, but excess current flows in the region adjacent to the electrode tab causing lithium precipitation
Solution Approach 1:
The patent applies local quality by dividing the active material layer into two distinct regions: a first active material layer with higher conductive additive content (1-3 wt%) in the region adjacent to the electrode tab, and a second active material layer with lower conductive additive content (0-1 wt%) in the remaining region. This localized variation in composition optimizes current distribution where needed while maintaining overall battery performance.
2Reliability
If the conductive additive ratio is increased in the active material layer, then current distribution is improved, but the area of the active material layer must be reduced to maintain energy density
Solution Approach 1:
The patent implements local quality by concentrating higher conductive additive content (1-3 wt%) specifically in the first active material layer adjacent to the electrode tab, while the second active material layer maintains lower conductive additive content (0-1 wt%). This localized approach improves current distribution only where needed, preserving maximum active material area for energy storage.
Solution Approach 2:
The patent segments the active material layer into two distinct functional zones: a first active material layer (with area ratio of 5-20% of total) containing higher conductive additive for current management, and a second active material layer (with area ratio of 80-95% of total) containing lower conductive additive for energy storage. This segmentation allows optimization of different regions for different functions.
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 design enhances battery life and performance by minimizing lithium precipitation and maintaining energy density, thereby improving the overall efficiency of the secondary battery.
Implementation Method 1
the 2-1 active material layer includes a first negative electrode active material, a 2-1 conductive additive, and a 2-1 binder, the 2-2 active material layer includes a second negative electrode active material, a 2-2 conductive additive, and a 2-2 binder, and a ratio of the 2-1 conductive additive is greater than the ratio of the 2-2 conductive additive
Data Source
AI summary
Example embodiments relate to electrode assemblies and secondary batteries capable of preventing or reducing lithium precipitation in a negative electrode. The example embodiments are to provide the secondary battery that may prevent or reduce lithium precipitation in the negative electrode by increasing the ratio of the conductive additive in the negative electrode active material layer adjacent to the lead tab. The electrode assembly includes a first electrode, a second electrode and a separator, the first electrode includes a first current collector and a first active material layer, the second electrode includes a second current collector and a second active material layer, the second current collector includes a second uncoated portion, the second uncoated portion includes a connection region to which a second lead tab is connected.