Dual-Material Cathode Layout for Low-SOC Voltage Stability
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Solution Overview
Problem
Lithium secondary batteries used in electric vehicles face issues with structural instability, leading to sudden voltage drops and decreased output in low state of charge (SOC) sections, necessitating improved stability and performance.
Innovation Solution
A cathode design featuring two cathode active materials with different operating voltage ranges, one with a lithium transition metal oxide and the other with a lithium phosphate compound, applied to different surfaces of a current collector, optimizing weight ratios and including conductive and binder materials to manage resistance and voltage drops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiCoO2 is used as cathode material for high energy density applications, then energy density is improved, but structural instability occurs leading to cell explosion
Solution Approach 1:
The patent uses a composite cathode material consisting of LiCoO2 particles coated with LiMn0.8Fe0.1Ni0.1O2. This composite structure combines the high energy density of LiCoO2 with the structural stability of the spinel coating layer, preventing cell explosion while maintaining high energy density performance.
2Reliability
If LiMnO2 or LiMn2O4 is used to improve stability of LiCoO2, then structural stability is improved, but energy density decreases
Solution Approach 1:
The patent creates a composite structure where LiCoO2 (high energy density) is coated with LiMn0.8Fe0.1Ni0.1O2 (high stability). The coating layer provides structural stability preventing cell explosion, while the LiCoO2 core maintains high energy density, achieving both stability and energy density simultaneously.
Data Source
AI summary
A cathode according to an embodiment of the present disclosure may include a cathode current collector including a first surface and a second surface; a first cathode material formed on the first surface of the cathode current collector; and a second cathode material formed on the second surface of the cathode current collector. Each of the first cathode material and the second cathode material may include a first cathode active material and a second cathode active material. The first cathode active material and the second cathode active material have different operating voltage ranges. The weight ratio of the first cathode active material and the second cathode active material included in the first cathode material and the weight ratio of the first cathode active material and the second cathode active material included in the second cathode material may be different.