NCM Cathode and Ethylene Carbonate Electrolyte for Lithium Battery
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Solution Overview
Problem
Lithium rechargeable batteries with high nickel content in their positive active material face challenges such as increased manufacturing costs, gas generation, and capacity deterioration, which affect their cycle-life and thermal stability.
Innovation Solution
A rechargeable lithium battery design incorporating a nickel-cobalt-manganese (NCM) composite oxide with nickel content between 63% and 85% atomic percentage, combined with an electrolyte containing ethylene carbonate between 7.5 to 27.5 volume % in a non-aqueous organic solvent, to enhance specific capacity and cycle-life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel content in NCM composite oxide is increased to improve specific capacity, then capacity characteristic is improved, but gas generation increases and cycle-life deteriorates
Solution Approach 1:
The patent optimizes the nickel content parameter within a specific range (63-85 atomic %) to balance capacity and cycle-life performance. Additionally, it adjusts the ethylene carbonate concentration parameter (7.5-27.5 volume %) in the electrolyte to suppress gas generation and improve high-temperature cycle characteristics, thereby resolving the contradiction between capacity and reliability
Solution Approach 2:
The patent uses a composite NCM (nickel-cobalt-manganese) oxide material that combines multiple metal elements. This composite structure allows the material to achieve high specific capacity from nickel while cobalt and manganese provide structural stability and suppress gas generation, thus improving cycle-life without sacrificing capacity
2Quantity of substance
If nickel content in NCM composite oxide is increased to improve specific capacity, then capacity characteristic is improved, but manufacturing cost increases
Solution Approach 1:
The patent defines an optimal nickel content range (63-85 atomic %) that achieves high specific capacity while avoiding excessive nickel content that would significantly increase manufacturing cost. This parameter optimization balances performance improvement with cost control
3Quantity of substance
If nickel content in NCM composite oxide is increased to improve specific capacity, then capacity characteristic is improved, but thermal stability deteriorates
Solution Approach 1:
The NCM composite oxide combines nickel (for high capacity) with cobalt and manganese (for thermal stability). This composite structure allows the material to achieve high specific capacity while maintaining thermal stability through the stabilizing effects of cobalt and manganese components
4Reliability
If ethylene carbonate content in electrolyte is increased to improve cycle-life characteristics, then gas generation decreases, but specific capacity may be affected
Solution Approach 1:
The patent optimizes the ethylene carbonate concentration within a specific range (7.5-27.5 volume %) to achieve the desired balance. This parameter optimization ensures sufficient gas suppression and cycle-life improvement while maintaining adequate specific capacity performance
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 effectively decreases gas generation and improves the cycle-life characteristics of lithium rechargeable batteries at high temperatures, maintaining high specific capacity and thermal stability.
Implementation Method 1
a positive electrode, which includes a positive active material that can intercalate and deintercalate lithium
Implementation Method 2
The rechargeable lithium batteries use an organic electrolyte solution
Implementation Method 3
The non-aqueous organic solvent includes ethylene carbonate in an amount of between 7.5 to 27.5 volume % based on a total amount of the non-aqueous organic solvent
Data Source
AI summary
A rechargeable lithium battery includes a positive electrode including a positive active material, a negative electrode including a negative active material and an electrolyte including a lithium salt and a non-aqueous organic solvent, wherein the positive active material includes a nickel-based composite oxide represented by the following Chemical Formula 1, the non-aqueous organic solvent includes ethylene carbonate, and the ethylene carbonate is included in an amount of 7.5 to 27.5 volume % based on the total amount of the non-aqueous organic solvent,LiNixCoyMnzO2 [Chemical Formula 1]wherein in Chemical Formula 1, 0.63≤x≤0.85, 0.05<y<0.25, 0.03<z<0.02 and x+y+z=1.