Lithium Battery Cathode Composite for High Output
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Solution Overview
Problem
Lithium secondary batteries used in electric vehicles and hybrid electric vehicles require high-output characteristics but are limited by the use of expensive cobalt-based cathode active materials and amorphous carbon with low energy density, which are not suitable for high-output applications.
Innovation Solution
A lithium secondary battery design incorporating a cathode with a layered lithium transition metal oxide and a spinel lithium manganese oxide, combined with amorphous carbon as the anode active material, to enhance capacity and output characteristics, along with a specific separator for improved stability and ion permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium cobalt composite oxide with layered structure is used as cathode active material, then battery capacity is maintained, but cost increases and output characteristics deteriorate
Solution Approach 1:
The patent uses a composite cathode active material consisting of lithium manganese oxide (spinel structure) as the main component (40-100 wt%) combined with lithium cobalt composite oxide (layered structure) (0-60 wt%). This composite approach leverages the high capacity of layered structure and the high output characteristics and stability of spinel structure, achieving both cost reduction and improved output characteristics without sacrificing battery capacity
Solution Approach 2:
The patent optimizes the composition ratio parameters of the composite cathode active material, specifically setting lithium manganese oxide content at 40-100 wt% and lithium cobalt composite oxide at 0-60 wt%. By adjusting these compositional parameters, the battery achieves enhanced output characteristics and cost-effectiveness while maintaining adequate capacity
2Power
If graphite is used as anode active material, then energy density is high, but high-output characteristics are poor
Solution Approach 1:
The patent employs amorphous carbon as the anode active material, which exhibits both high energy density (300 mAh/g or greater) and superior high-output characteristics compared to conventional graphite. The amorphous carbon structure provides better ion transport pathways and electrical conductivity, enabling the battery to deliver high power output while maintaining high energy density
3Quantity of substance
If amorphous carbon with capacity less than 300 mAh/g is used as anode, then manufacturing is easier, but energy density is insufficient for high-output applications
Solution Approach 1:
The patent specifies amorphous carbon with a capacity of 300 mAh/g or greater, establishing a clear parameter threshold that ensures both high energy density and high-output characteristics. This parameter specification guides material selection and manufacturing processes to achieve the desired performance level
Data Source
AI summary
Disclosed is a high-output lithium secondary battery including: a cathode that includes, as cathode active materials, a first cathode active material represented by Formula 1 below and having a layered structure and a second cathode active material represented by Formula 2 below and having a spinel structure, wherein the amount of the second cathode active material is between 40 and 100 wt% based on the total weight of the cathode active materials; an anode including amorphous carbon having a capacity of 300 mAh/g or greater; and a separator.