Composite Cathode Material for High-Power Lithium Batteries
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Solution Overview
Problem
Lithium manganese composite oxide cathodes in secondary batteries degrade due to manganese ion elution at high temperatures and high-current charge/discharge cycles, limiting their service life and safety, especially in electric vehicles, and have lower charge density compared to cobalt or nickel-based oxides.
Innovation Solution
A cathode active material comprising a mixture of lithium/manganese spinel oxide and lithium/nickel/cobalt/manganese composite oxide with an average particle diameter of 15 to 30 µm, which inhibits electrolyte decomposition and manganese dissolution, enhancing safety and life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium manganese composite oxide is used as cathode material, then cost and safety are improved, but service life deteriorates due to manganese ion elution at high temperature and high-current charge/discharge
Solution Approach 1:
The patent uses a composite cathode material consisting of lithium manganese spinel oxide particles (with average particle diameter of 15 µm or more) and lithium nickel cobalt manganese composite oxide particles. This composite structure combines the safety and cost advantages of lithium manganese oxide with the stability of lithium nickel cobalt manganese oxide, preventing manganese ion elution while maintaining good cycle life and safety performance.
2Reliability
If lithium manganese composite oxide is used as cathode material, then cost and safety are improved, but charge density deteriorates due to low capacity per unit weight
Solution Approach 1:
The patent employs a composite material system where lithium manganese spinel oxide (providing safety and cost benefits) is combined with lithium nickel cobalt manganese composite oxide (providing higher capacity). This composite approach achieves a balance between safety and charge density, with the lithium nickel cobalt manganese component compensating for the lower specific capacity of lithium manganese oxide.
3Power
If high-current charge/discharge cycles are repeated, then power output is improved, but service life deteriorates due to manganese ion elution into electrolyte
Solution Approach 1:
The composite cathode material combines lithium manganese spinel oxide (good for high-power output) with lithium nickel cobalt manganese composite oxide (excellent cycle stability). This combination allows the battery to deliver high power output through high-current charge/discharge while the stable lithium nickel cobalt manganese component prevents manganese ion elution, maintaining service life even under severe cycling conditions.
4Use of energy by moving object
If high-temperature operation is performed, then energy delivery is improved, but safety deteriorates due to electrolyte decomposition and manganese dissolution
Solution Approach 1:
The patent uses a composite material where lithium manganese spinel oxide (enabling high energy delivery) is combined with lithium nickel cobalt manganese composite oxide (providing high-temperature stability). This composite structure prevents electrolyte decomposition and manganese dissolution at high temperatures while maintaining excellent energy delivery capability, achieving both high energy output and superior safety at elevated temperatures.
Data Source
AI summary
Provided is a non-aqueous electrolyte-based, high-power lithium secondary battery having a long service life and superior safety at both room temperature and high temperature, even after repeated high-current charging and discharging. The battery comprises a cathode active material composed of a mixture of lithium/manganese spinel oxide and lithium/nickel/cobalt/manganese composite oxide wherein at least one of two oxides has an average particle diameter of more than 15 μm.