Polymer-Coated Anode Composition for Crack-Resistant Roll Pressing
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Solution Overview
Problem
Cracks often occur in electrodes of lithium-ion batteries during compression molding using a roll press, which affects the integrity and performance of the electrodes.
Innovation Solution
An anode composition for lithium-ion batteries comprising coated anode active material particles with a polymer compound coating and a conductive filler, where the ratio of aerated bulk density to packed bulk density is maintained between 0.40 to 0.65, enhancing the electrode's strength and reducing the likelihood of cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electrode active material is compression molded using a roll press, then production time and energy are reduced, but cracks occur in the electrode
Solution Approach 1:
The invention changes the physical parameters of the electrode mixture by controlling the bulk density ratio (aerated/packed) to be 0.40-0.65 and using particles with specific true density (1.8-2.2 g/mL). These parameter changes optimize the mixture's compressibility and internal structure, allowing compression molding to proceed without crack formation while maintaining high production efficiency.
Solution Approach 2:
The invention uses a composite electrode mixture comprising electrode active material particles, conductive filler particles, and binder in specific proportions. This composite structure, where different materials work together, creates a more robust mixture that resists cracking during compression molding while maintaining good electrical conductivity and adhesion.
2Use of energy by stationary object
If electrode active material is compression molded using a roll press, then production energy is reduced, but cracks occur in the electrode
Solution Approach 1:
By optimizing the bulk density ratio and particle true density, the invention creates an electrode mixture that requires less compression energy to form a dense, crack-free structure. The specific particle properties enable efficient energy transfer during compression, reducing overall production energy consumption while preventing crack formation.
3Ease of manufacture
If electrode mixture is compression molded, then manufacturing efficiency is improved, but electrode strength is compromised due to cracks
Solution Approach 1:
The invention optimizes manufacturing efficiency by establishing specific parameter ranges for the electrode mixture (bulk density ratio 0.40-0.65, true density 1.8-2.2 g/mL) that enable crack-free compression molding. These parameter changes allow high-speed roll press manufacturing while producing electrodes with superior strength and integrity.
Solution Approach 2:
The composite electrode mixture with optimized composition ratios creates a synergistic effect where the binder provides adhesion, conductive filler maintains electrical pathways, and active material particles pack efficiently. This composite structure achieves both ease of manufacture and high electrode strength simultaneously.
Data Source
AI summary
An anode composition for lithium-ion batteries comprises: a coated anode active material particle, wherein at least a part of an anode active material particle surface is coated by a coating layer that contains a polymer compound; and a conductive filler, wherein the ratio of an aerated bulk density to a packed bulk density (aerated bulk density/packed bulk density) is 0.40 to 0.65.