Lithium-rich compound doped anode for thermal runaway prevention
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Solution Overview
Problem
Lithium-ion batteries, particularly those with high nickel ternary materials, face challenges in safety performance due to poor high-temperature stability and susceptibility to thermal runaway, which affects their widespread adoption in power cells and electric vehicles.
Innovation Solution
Incorporating a lithium-rich compound, such as lithium-rich manganese-based solid solutions, lithium-rich solid electrolytes, or lithium-separated silicon oxides, into the positive piece of lithium batteries to stabilize the crystal lattice structure and improve thermal stability, thereby enhancing safety performance and maintaining high cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high nickel ternary materials are used to increase power density and driving mileage, then energy density and specific capacity are improved, but thermal stability deteriorates and the material becomes prone to thermal runaway
Solution Approach 1:
The patent uses composite materials by combining high nickel ternary cathode material with aluminum oxide coating and lithium-rich compound doping. The aluminum oxide coating layer provides thermal stability while the lithium-rich compound dopant suppresses oxygen evolution, achieving both high energy density and improved thermal stability through material composition design
Solution Approach 2:
The patent applies local quality by concentrating the lithium-rich compound dopant at specific locations and interfaces within the cathode material structure. The dopant is introduced to specifically target regions prone to oxygen evolution and thermal degradation, providing localized stabilization without compromising overall energy density
2Quantity of substance
If the nickel content in ternary material is increased to improve specific capacity, then power density increases, but safety performance deteriorates due to poor high temperature stability
Solution Approach 1:
The patent introduces aluminum oxide as an intermediary substance that forms a protective coating layer between the high nickel ternary cathode material and the electrolyte. This intermediary layer acts as a thermal barrier and prevents direct contact that would lead to thermal runaway, thereby improving safety performance while maintaining high specific capacity
Solution Approach 2:
The patent changes the chemical composition parameters of the cathode material by doping with lithium-rich compounds and controlling the aluminum oxide coating thickness. These parameter changes optimize the balance between nickel content for capacity and safety mechanisms, achieving high specific capacity with improved safety performance
3Reliability
If aluminum oxide coating is applied to improve safety performance, then thermal stability is improved, but energy density may be reduced due to coating material displacement
Solution Approach 1:
The patent optimizes the aluminum oxide coating thickness parameter to a specific range that provides sufficient thermal protection while minimizing the volume fraction of non-active coating material. This parameter optimization ensures that the coating provides safety benefits without excessive displacement of energy-storing cathode material
Solution Approach 2:
The patent creates a composite structure where aluminum oxide coating is combined with lithium-rich compound doping within the cathode material matrix. This composite approach allows the coating to provide safety functions while the doped lithium-rich compound maintains electrochemical activity, reducing the net loss of energy density
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 lithium-rich compounds effectively pull away lithium ions under extreme conditions, reducing oxidation states and improving safety performance, allowing the batteries to pass tests like piercing and high-temperature exposure without thermal runaway, while maintaining high energy density and cycle life.
Implementation Method 1
Lithium-ions can be pulled away from the lithium-rich compound in extreme conditions such as overcharging, high temperature, piercing, compressing, internal short circuiting, external short circuiting, thermal abuse or overheating, thereby filling in lithium vacancies in the anode material, stabilizing the crystal lattice structure of the anode material
Implementation Method 2
reducing the oxidized state of anode under the extreme conditions, stabilizing the crystal lattice structure of the anode material, improving safety performance in a battery manufactured by using the material
Data Source
AI summary
An anode piece for a lithium battery having both high safety and high capacity, and a preparation method and a use therefor, the anode piece being mixed with a lithium-rich compound, the lithium-rich compound being at least one selected from lithium-rich manganese-based solid solution, a lithium-rich solid electrolyte or a lithium-separated silicon oxide. Li ions can be pulled away from the lithium-rich compound in extreme conditions such as overcharging, internal short circuiting, external short circuiting, thermal abuse, piercing, compressing or overheating, thereby filling in lithium vacancies in the anode material, stabilizing the crystal lattice structure of the anode material, improving safety performance in a battery manufactured by using the material, and allowing the anode piece to maintain excellent cycle performance at higher area capacities.