High-Nickel Li-Ion Cathode and Electrolyte for Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-nickel ternary positive electrode materials in lithium-ion secondary batteries face challenges in thermal stability due to the production of reactive oxygen and heat, leading to thermal runaway, especially in extreme temperatures, which can cause safety accidents.
Innovation Solution
A lithium-ion secondary battery design incorporating a positive electrode active substance of LiNixCoyNzM1-x-y-zO2 and an electrolyte composed of specific compounds represented by formulas (1), (2), and (3), with optimized weight percentages and ratios, enhances thermal stability and safety performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the amount of nickel in the positive electrode active substance is increased to increase energy density, then the energy density is improved, but the thermal stability of the positive electrode active substance drops
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode active substance by introducing a specific element M (selected from Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, Ti) and controlling the ratios of Ni, Co, Mn, and M atoms. This parameter change allows achieving high nickel content (x≥0.5) while maintaining thermal stability through the stabilizing effect of element M on the crystal structure.
Solution Approach 2:
The patent creates a composite positive electrode active substance with multiple elements (Li, Ni, Co, Mn, and M) in a specific composition LiNixCoyNzM1-x-y-zO2. This composite material combines the high capacity benefit of nickel with the structural stability provided by other elements, particularly element M, which forms a stable crystal structure that prevents thermal runaway even at high nickel contents.
2Stability of the object's composition
If the thermal stability is improved by reducing nickel content or adding stabilizing elements, then the thermal stability is improved, but the energy density decreases
Solution Approach 1:
The patent optimizes the compositional parameters within the spinel structure LiNixCoyNzM1-x-y-zO2, specifically controlling the sum of Ni, Co, and Mn content (x+y+z≤0.95) while ensuring sufficient nickel content (x≥0.5) for high energy density. The introduction of element M with controlled concentration (0.05≤1-x-y-z≤0.30) provides thermal stability without significantly compromising capacity.
3Quantity of substance
If high-nickel ternary positive electrode material is used to increase energy density, then the energy density is improved, but the thermal runaway temperature decreases and safety issues arise
Solution Approach 1:
The patent changes the chemical composition parameters to achieve a balance between energy density and safety. By controlling the nickel content (x≥0.5) and introducing element M with specific concentration ranges, the material maintains high capacity while the crystal structure stabilized by element M prevents oxygen release and electrolyte decomposition at elevated temperatures, thereby improving safety.
Solution Approach 2:
Element M acts as an intermediary stabilizing element in the spinel structure. It mediates between the high-energy nickel sites and the lithium ions, maintaining structural integrity during charging and discharging cycles. This intermediary element prevents direct contact and reaction between nickel and electrolyte, reducing the risk of thermal runaway while preserving high energy density.
Data Source
AI summary
This application relates to a lithium-ion secondary battery. A positive electrode plate of the lithium-ion secondary battery includes a positive electrode active substance LiNixCoyNzM1-x-y-zO2, with N selected from Mn and Al, and M selected from any one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V, and Ti, where 0.5≤x<1, 0≤y≤1, 0≤z≤1, and x+y+z≤1; and an electrolyte of the lithium-ion secondary battery contains a specified amount of compounds represented by formula (1), formula (2), and formula (3). The lithium-ion secondary battery of this application has both high energy density and high thermal stability. This application further relates to a battery module containing the lithium-ion secondary battery, a battery pack, and an electric apparatus.