Cathode Active Material Composition for Dense Low-Moisture Electrodes
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Solution Overview
Problem
Existing secondary battery technologies face challenges in achieving high energy density and good electrochemical performance due to high water content and low compaction density in water-based positive electrode slurries, which leads to safety and performance issues.
Innovation Solution
A positive electrode active material composition comprising three materials with different particle sizes (Dv50 ranging from 0.2 μm to 6.0 μm) is used, which synergistically improves compaction density and reduces water content, enhancing ion and electron transport performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-based solvent is used in positive electrode slurry, then environmental friendliness and cost are improved, but compaction density decreases and water content increases
Solution Approach 1:
The patent changes the particle size parameters of positive electrode active materials by dividing them into three distinct size ranges (first: 0.2-0.8μm, second: 1.0-2.5μm, third: 3.0-6.0μm). This parameter differentiation allows small particles to fill voids between larger particles, increasing compaction density while maintaining water-based solvent benefits.
Solution Approach 2:
The patent creates a composite particle size distribution system by combining three types of positive electrode active materials with different particle sizes in specific weight ratios (first: 60-80%, second: 10-40%, third: 7-15%). This composite approach enables dense packing while using environmentally friendly water-based solvent.
2Object-affected harmful factors
If water-based solvent is used in positive electrode slurry, then environmental friendliness and cost are improved, but water content increases leading to safety issues
Solution Approach 1:
The patent changes the particle size parameters to create a multi-size distribution that optimizes packing efficiency. The three distinct size ranges enable better space utilization, reducing the volume occupied by water and thus lowering water content in the electrode structure.
Solution Approach 2:
The patent applies different particle size qualities to different regions of the electrode structure. Smaller particles (first size range) fill local voids between larger particles, creating a hierarchical structure that reduces overall water content while maintaining the water-based solvent system.
3Ease of manufacture
If single particle size positive electrode active material is used, then manufacturing simplicity is maintained, but compaction density and ion transport performance decrease
Solution Approach 1:
The patent introduces particle size as a critical parameter variable, dividing positive electrode active materials into three size categories. This parameter change enables denser packing and improved ion transport while maintaining relatively simple manufacturing processes through controlled mixing in specified weight ratios.
Solution Approach 2:
The patent segments the positive electrode active material into three distinct particle size groups rather than using a single uniform size. This segmentation allows each size category to fulfill specific functions: large particles provide structural framework, medium particles fill intermediate spaces, and small particles fill voids, collectively improving compaction density.
4Ease of manufacture
If single particle size positive electrode active material is used, then manufacturing simplicity is maintained, but electrochemical performance decreases
Solution Approach 1:
The patent changes the particle size parameter distribution to three distinct ranges, which improves electrochemical performance by optimizing ion transport pathways. The multi-size structure provides both short pathways (through small particles) and structural stability (through large particles), enhancing overall battery reliability.
Solution Approach 2:
The patent creates a composite particle size system combining three types of positive electrode active materials in specific weight ratios. This composite structure synergistically improves electrochemical performance by combining the advantages of different particle sizes while maintaining manufacturability through straightforward mixing procedures.
Data Source
AI summary
A positive electrode active material composition, a water-based positive electrode slurry, a positive electrode plate, a secondary battery, and an electrical device are disclosed. The positive electrode active material composition includes a first positive electrode active material, a second positive electrode active material, and a third positive electrode active material, the first positive electrode active material has a volume average particle size Dv50 denoted as A1 in μm, with A1 satisfying 0.2≤A1≤0.8; the second positive electrode active material has a volume average particle size Dv50 denoted as A2 in μm, with A2 satisfying 1.0≤A2≤2.5; and the third positive electrode active material has a volume average particle size Dv50 denoted as A3 in μm, with A3 satisfying 3.0≤A3≤6.0. The positive electrode plate of the present application has both a higher compaction density and a lower water content.