Electrode Sheet Coating for Low-Heat Lithium Supplementation
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Solution Overview
Problem
Existing lithium supplementation methods in batteries, such as direct addition of lithium powder or foil, result in excessive heat generation and poor SEI formation, leading to battery attenuation and reduced cycle performance.
Innovation Solution
An electrode sheet with a surface-coated active material layer, featuring an intermediate solid electrolyte layer and a lithium-supplementing layer composed of self-decomposing lithium compounds, which generates lithium ions during charging and discharging, reducing heat and enhancing lithium supplementation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium powder or lithium foil is directly added to the electrode sheet for lithium supplementation, then the lithium content is increased, but excessive heat is generated and poor SEI formation occurs
Solution Approach 1:
The patent introduces an intermediate layer between the lithium supplementing layer and the active material layer. This intermediate layer acts as a mediator that prevents direct contact between lithium metal and the active material, thereby avoiding excessive heat generation during lithium supplementation while still enabling lithium ion transfer to maintain battery capacity.
2Quantity of substance
If lithium powder or lithium foil is directly added to the electrode sheet for lithium supplementation, then the lithium content is increased, but poor SEI formation occurs and battery attenuation increases
Solution Approach 1:
The intermediate layer serves as a mediator that facilitates controlled SEI formation. By preventing direct contact between lithium metal and the active material, it allows for gradual and uniform SEI development during charging cycles, improving battery reliability and reducing attenuation over time.
Solution Approach 2:
The intermediate layer is pre-formed on the electrode surface before lithium supplementation occurs. This preliminary structure provides a controlled interface that guides subsequent SEI formation, ensuring uniform and stable protective layer development that enhances long-term battery performance.
3Quantity of substance
If the short-circuit method is used for lithium supplementation, then lithium content is increased, but excessive heat is generated and SEI cannot be generated during voltage reduction
Solution Approach 1:
The intermediate layer acts as a thermal and electrical mediator that prevents the short-circuit conditions associated with direct lithium metal contact. It allows controlled lithium ion transfer while maintaining electrical isolation, thereby avoiding excessive heat generation and enabling proper SEI formation during normal voltage operation.
4Quantity of substance
If lithium metal is used for supplementation, then lithium content is increased, but lithium reacts with moisture and air generating heat
Solution Approach 1:
The intermediate layer serves as a protective barrier that isolates lithium metal from environmental factors such as moisture and air. This mediator prevents direct reaction between lithium and harmful external elements, eliminating the heat generation problem associated with lithium's high reactivity while still allowing lithium ion supplementation to occur.
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 inhibits heat generation during lithium supplementation, reduces active lithium loss, and improves battery electrochemical performance by maintaining high first efficiency and cycle performance.
Implementation Method 1
a lithium-supplementing layer is arranged on the upper surface of the intermediate layer, the lithium-supplementing layer including a lithium-containing compound capable of self-decomposing to generate lithium ions
Implementation Method 2
The intermediate layer includes a solid electrolyte
Data Source
AI summary
The invention provides an electrode sheet, the surface of the active material layer of the electrode sheet is provided with an intermediate layer and a lithium-supplementing layer, the intermediate layer includes a solid electrolyte, and the lithium-supplementing layer includes a lithium-containing compound that self-decomposes to produce lithium ions. The electrode sheet of the present invention may effectively suppress the heat generated in the lithium supplementing process, and overcome the defect of continuous consumption of active lithium ions in the continuous growth of the SEI layer. Therefore, the electrode sheet provided by the present invention has excellent lithium supplementation effect and electrochemical performance.