Lithium Manganese Composite Cathode for High-Temperature Stability
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Solution Overview
Problem
Lithium manganese composite oxide cathodes in lithium-ion batteries suffer from manganese ion elution at high temperatures and low charge density, limiting their service life and safety for use in electric vehicles and hybrid electric vehicles.
Innovation Solution
A cathode active material comprising a mixture of lithium manganese-metal composite oxide with a spinel structure and lithium nickel-manganese-cobalt composite oxide with a layered structure, where the manganese in the spinel structure is substituted with other metals like Al, Mg, Ni, Co, Fe, Ti, V, or Zn, and the composition ratios of nickel, manganese, and cobalt are optimized to enhance high-temperature stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lithium manganese composite oxide is used as cathode material, then cost and safety are improved, but manganese ion elution occurs at high temperature leading to degradation of battery properties
Solution Approach 1:
The patent uses a composite cathode material consisting of lithium manganese oxide (spinel structure) combined with lithium nickel-manganese-cobalt oxide (layered structure). This composite approach leverages the safety and cost advantages of lithium manganese oxide while incorporating lithium nickel-manganese-cobalt oxide to suppress manganese ion elution at high temperatures, thereby maintaining battery reliability.
Solution Approach 2:
The patent optimizes the compositional parameters of the cathode materials, specifically controlling the ratios of metal elements (nickel, manganese, cobalt) in the lithium nickel-manganese-cobalt oxide component. By adjusting these parameters, the material achieves high-temperature stability that prevents manganese ion elution while maintaining good electrochemical performance.
2Object-affected harmful factors
If lithium manganese composite oxide is used as cathode material, then cost and safety are improved, but charge density is reduced
Solution Approach 1:
The composite cathode material combines lithium manganese oxide (which provides cost and safety advantages) with lithium nickel-manganese-cobalt oxide (which provides high charge density). This composite structure allows the battery to achieve both cost-effectiveness and high charge density by leveraging the complementary strengths of each material component.
Solution Approach 2:
The patent optimizes the compositional parameters, specifically controlling the metal element ratios in the lithium nickel-manganese-cobalt oxide component to maximize charge density while maintaining cost-effectiveness. The optimized composition enables the cathode material to achieve high charge density without sacrificing the cost advantages of lithium manganese oxide-based systems.
3Power
If high current charge/discharge cycles are repeated, then power output is improved, but service life is reduced
Solution Approach 1:
The composite cathode material provides both high power output capability and long service life by combining the advantages of lithium manganese oxide (structural stability for long cycle life) with lithium nickel-manganese-cobalt oxide (high power density). This composite structure enables the battery to maintain performance under high current conditions while extending overall service life.
Solution Approach 2:
The patent optimizes compositional parameters to achieve a balance between power output and service life. By carefully controlling the metal element ratios in the composite cathode material, the battery achieves high power density capability while maintaining structural stability that prevents degradation during repeated high current charge/discharge cycles, thereby extending service life.
4Power
If high temperature conditions are applied, then power output capability is improved, but manganese ion elution increases causing safety issues
Solution Approach 1:
The composite cathode material suppresses manganese ion elution at high temperatures by combining lithium manganese oxide with lithium nickel-manganese-cobalt oxide. The lithium nickel-manganese-cobalt oxide component provides high-temperature stability that prevents manganese ion dissolution into the electrolyte, thereby maintaining safety while enabling high power output capability under elevated temperature conditions.
Solution Approach 2:
The patent optimizes compositional parameters, specifically the metal element ratios in the lithium nickel-manganese-cobalt oxide component, to maximize high-temperature stability. This parameter optimization ensures that the cathode material maintains structural integrity at high temperatures, preventing manganese ion elution while preserving power output capability.
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 solution improves the high-temperature cycle characteristics and capacity retention of lithium-ion batteries, inhibiting manganese ion elution and increasing charge density, thereby extending the battery's service life and ensuring safety, especially under high current and high-temperature conditions.
Implementation Method 1
the lithium manganese composite oxide, upon high-temperature and high current charge/discharge, undergoes elution of manganese ions into an electrolyte due to the influence of the electrolyte, thus resulting in degradation of battery properties and performance
Data Source
AI summary
The present invention provides a non-aqueous electrolyte-based high power lithium secondary battery having a long-term service life and superior safety at both room temperature and high temperature, even after repeated high-current charging and discharging, wherein the battery comprises a mixture of a particular lithium manganese-metal composite oxide (A) having a spinel structure and a particular lithium nickel-manganese-cobalt composite oxide (B) having a layered structure, as a cathode active material.