Battery Electrode Active Material Packing to Limit Rolling Breakage
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Solution Overview
Problem
The breakage of active substance particles during the rolling process in lithium-ion battery electrode manufacturing leads to electrolyte permeation and reduced cycle life, as existing technologies fail to effectively prevent particle breakage and maintain optimal electrode density.
Innovation Solution
An electrode plate with an active substance comprising spherical powder particles and monocrystalline particles of specific size ratios, where the larger particles provide mechanical strength and the smaller particles fill gaps, reducing breakage rates and enhancing packing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If particles of active substance are added to increase coating layer density through particle packing, then energy density is improved, but particle breakage occurs during rolling process
Solution Approach 1:
The active substance is segmented into two distinct particle size groups: larger particles (D50: 5-20 μm) that form the structural framework and smaller particles (D50: 1-5 μm) that fill interstitial spaces. This segmentation allows the larger particles to maintain structural integrity while smaller particles pack efficiently, achieving high coating layer density without compromising particle strength during rolling
Solution Approach 2:
Smaller particles are nested within the interstitial spaces between larger particles, creating a hierarchical packing structure. This nested arrangement maximizes space utilization and coating layer density while the larger outer particles provide mechanical protection and structural stability during the rolling process
2Quantity of substance
If rolling process is applied to improve coating layer density, then electrode density is increased, but particle breakage rate increases
Solution Approach 1:
The particle size distribution parameters are specifically controlled with D50 values of 5-20 μm for larger particles and 1-5 μm for smaller particles, with a size ratio of 1:3 to 1:10. This parameter optimization enables the electrode to achieve density >3.5 g/cm³ while maintaining breakage rate ≤40%, balancing density improvement with cycle life reliability
3Quantity of substance
If particle packing is performed to increase energy density, then coating layer density improves, but crystal structure and size variations lead to particle breakage
Solution Approach 1:
Different regions of the particle mixture serve different functions: larger particles (D50: 5-20 μm) with specific crystal structures provide structural stability and resistance to breakage, while smaller particles (D50: 1-5 μm) fill gaps and enhance packing density. This local quality differentiation ensures that structural stability is maintained in critical regions while achieving high overall density
Data Source
AI summary
An electrode plate having active substance of electrochemical energy storage device is provided in the present invention, including a current collector and an electrode formed of active substance on the current collector, wherein the active substance includes first particles in form of spherical powder and second particles in form of monocrystalline structure, and an average particle size of the first particles is larger than or equal to three times of an average particle size of the second particles, and a volume ratio of the first particles in the active substance is greater than a volume ratio of the second particles in the active substance, and a breakage rate of said electrode formed by mixed first particles and second particles in rolling pressing process is smaller than or equal to 40%.