Column Current Collectors for High-Loading Electrode Integrity
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Solution Overview
Problem
High-loading electrodes in lithium secondary batteries face issues such as cracking, non-uniform loading, and separation of the electrode active material layer due to high loading and viscosity of the electrode active material slurry during the winding process.
Innovation Solution
The electrode assembly features a novel structure with through-holes in the positive and negative electrode active material layers, where column-like current collectors pass through these holes, providing a rigid block shape and reducing internal resistance by being in close contact with the inner surfaces, and insulation layers prevent short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of electrode active material is increased to achieve high-loading electrode, then the capacity is improved, but cracking occurs at coating portion and non-uniform loading occurs
Solution Approach 1:
The electrode assembly is divided into multiple stacked layers (first electrode assembly, second electrode assembly, third electrode assembly) with current collectors positioned between them. This segmentation allows the total loading amount to be distributed across multiple sections, preventing excessive loading in any single coating portion and thereby preventing cracking while maintaining high overall capacity.
2Quantity of substance
If the electrode thickness is increased to achieve high-loading electrode, then the capacity is improved, but separation of electrode active material occurs during winding
Solution Approach 1:
The electrode structure employs a nested configuration where the first current collector is positioned within the thickness direction of the electrode assembly, extending from the first electrode to the third electrode. This nested current collector acts as an internal support framework that prevents separation of the electrode active material layers during winding and handling, while allowing each layer to maintain its structural integrity.
3Quantity of substance
If the electrode thickness is increased to achieve high-loading electrode, then the capacity is improved, but internal resistance increases
Solution Approach 1:
Instead of simply increasing electrode thickness in one dimension, the invention introduces current collectors that extend in the thickness direction, creating a three-dimensional conductive network. This dimensional change provides multiple parallel current pathways through the electrode assembly, reducing overall internal resistance while maintaining high loading amounts of active material.
Data Source
AI summary
An electrode assembly having a positive electrode current collector, a positive electrode active material layer, a separator, a negative electrode active material layer and a negative electrode current collector stacked successively in a thickness direction of the electrode assembly is provided. A plurality of through-holes is formed to pass through the positive electrode active material layer, separator and the negative electrode active material layer. The positive electrode current collector includes a first sheet shaped current collector and a plurality of first column shaped current collectors extending from the first sheet shaped current collector along the thickness direction of the electrode assembly. The negative electrode current collector includes a second sheet shaped current collector and a plurality of second column shaped current collectors extending from the second sheet shaped current collector along the thickness direction of the electrode assembly.