Lithium Nickel Composite Oxide Particle Orientation for Battery Cracking
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Solution Overview
Problem
Lithium nickel composite oxide-based positive electrode materials for non-aqueous electrolyte lithium-ion batteries face challenges with cracking during high-output power discharges at high temperatures, leading to decreased capacity and output power, and inadequate cyclic endurance.
Innovation Solution
The use of secondary particles composed of primary lithium-nickel composite oxide particles with varying aspect ratios, where at least some primary particles are oriented with their longitudinal direction towards the center of the secondary particle, preventing cracking and enhancing cyclic endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium nickel composite oxide is used as positive electrode active material, then output power and high temperature stability are improved, but cracking occurs during repeated high output power discharges at high temperature leading to decreased capacity and output power
Solution Approach 1:
The positive electrode active material is divided into secondary particles that are agglomerates of multiple primary particles. This segmentation allows the secondary particles to maintain structural integrity during expansion and contraction, preventing cracking while preserving high output power capability. The secondary particle structure with controlled porosity (2-20%) accommodates volume changes without compromising the overall electrode performance.
Solution Approach 2:
The invention introduces specific local structural features including minute vacancies (2-20% porosity) within secondary particles and controlled arrangement of primary particles. These local quality modifications create buffer zones that absorb stress during high temperature discharge cycles, preventing crack propagation while maintaining the high power output characteristics of lithium nickel composite oxide.
2Ease of manufacture
If secondary particles with radial arrangement of primary particles are used, then manufacturing progress is achieved, but cracking still occurs leading to insufficient cyclic endurance
Solution Approach 1:
The invention modifies critical parameters including porosity (2-20%), primary particle size (0.1-10 μm), and secondary particle size (1-20 μm). By optimizing these parameters, the material achieves both manufacturability through conventional processes and improved cyclic endurance. The controlled porosity and size distribution prevent crack formation during repeated high temperature discharges while maintaining ease of manufacture.
3Length of stationary object
If thin type laminated battery structure is used, then battery thickness is reduced, but high output power requirements for electric vehicles cannot be met
Solution Approach 1:
The invention uses composite lithium nickel composite oxide particles with specific structural characteristics (secondary particles containing primary particles with controlled porosity). This composite structure enables the battery to achieve high output power density in a thin form factor, suitable for electric vehicle applications. The optimized particle morphology and porosity allow efficient ion transport while maintaining structural integrity.
Data Source
AI summary
An object of the present invention is to provide a positive electrode material for non-aqueous electrolyte lithium-ion battery which capable of discharging high output power and inhibiting cracking of secondary particle in the cyclic endurance at a high temperature. The above object can be attained by a positive electrode material for non-aqueous electrolyte lithium-ion battery of the present invention, characterized in that said material comprises secondary particles composed of primary particles of lithium nickel composite oxide containing the primary particles having different aspect ratios, and that at least a part of said primary particles having different aspect ratios are arranged so as to make the longitudinal direction (the long side direction) thereof oriented toward the center of the secondary particle.