Positive Electrode Quasi-Single Particles for Crack-Resistant Solid Batteries
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Solution Overview
Problem
Existing lithium secondary batteries face issues with electrode material deterioration, organic solvent evaporation, combustion risks, and production costs due to crack generation and aggregation during the manufacturing of all-solid-state batteries using multi-particles or single particles as electrode active materials.
Innovation Solution
The use of quasi-single particles with specific characteristics as the positive electrode active material, which are agglomerates of 2 to 20 primary particles, improves lithium ion conduction and reduces crack generation, allowing for improved battery life and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multi-particles are used as electrode active material, then manufacturing cost is reduced, but cracks occur during pressing process and voids occur at the interface between electrode active material and solid electrolyte
Solution Approach 1:
The invention segments the particle structure into primary particles (1-3 μm) that aggregate to form quasi-single particles (20 or fewer primary particles). This segmentation allows the material to maintain low manufacturing costs associated with multi-particle processing while the controlled aggregation prevents crack generation and void formation by ensuring adequate particle strength and interface contact.
Solution Approach 2:
The invention changes the particle size parameter to 1-3 μm for primary particles and controls the aggregation degree to 20 or fewer primary particles per quasi-single particle. This parameter optimization resolves the contradiction by providing particles small enough to reduce void formation but large enough to maintain structural integrity during pressing.
2Reliability
If single particles are used as electrode active material, then crack generation is reduced, but aggregation easily occurs during manufacture requiring additional crushing process
Solution Approach 1:
Instead of completely preventing aggregation (which would require crushing), the invention allows partial aggregation to form quasi-single particles with 20 or fewer primary particles. This partial aggregation approach maintains adequate particle strength to prevent cracks while avoiding excessive aggregation that would require additional crushing processes.
Solution Approach 2:
The invention optimizes the aggregation parameter to 20 or fewer primary particles per quasi-single particle, which is enough to prevent crack generation but not so much that additional crushing is needed. This parameter control resolves the contradiction between crack reduction and manufacturing efficiency.
3Object-affected harmful factors
If solid electrolyte is used, then safety is improved by excluding organic solvents, but voids occur at the interface due to non-fluid properties
Solution Approach 1:
The invention applies local quality by optimizing the particle size and aggregation state specifically at the interface region between electrode active material and solid electrolyte. The quasi-single particle structure (20 or fewer primary particles of 1-3 μm) ensures adequate contact area and pressure distribution at the interface, preventing void formation while maintaining the safety benefits of solid electrolyte.
Solution Approach 2:
The invention changes the particle size parameter to 1-3 μm and controls aggregation to 20 or fewer primary particles, which optimizes the contact interface properties between the electrode active material and solid electrolyte. This parameter optimization ensures adequate interface contact to prevent voids while maintaining the non-fluid advantages of solid electrolyte.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The quasi-single particles enhance lithium ion conductivity at the interface with the solid electrolyte, reducing crack generation and aggregation, leading to improved battery life and productivity without additional milling processes.
Implementation Method 1
a solid electrolyte having a sulfide-based glass composition; where lithium ion conduction is secured at the interface between the solid electrolyte and the positive electrode
Data Source
AI summary
The present invention relates to a positive electrode for a lithium secondary battery, a method of manufacturing the same and a lithium secondary battery comprising the same.