Negative Electrode Insulating Layer for Battery Short-Circuit Prevention
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Solution Overview
Problem
Lithium-ion secondary batteries face issues with internal short circuits and heat generation due to the continuous flow of electric current, which affects their performance and safety, and existing solutions have not adequately addressed these problems.
Innovation Solution
A negative electrode for lithium-ion secondary batteries is designed with a higher content ratio of insulating material, such as alumina particles, relative to conductive material in the negative electrode active material layer to prevent conductivity by percolation paths, thereby limiting the flow of short-circuit current and maintaining electrical resistance at a level that does not significantly impair battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the negative electrode active material layer is increased to improve energy density, then lithium metal deposition occurs due to increased charge density
Solution Approach 1:
An insulating material layer is introduced as an intermediary between the negative electrode active material particles. This insulating layer acts as a mediator that prevents direct contact and electron transfer between particles, thereby suppressing lithium metal deposition while allowing the electrode structure to maintain high energy density through increased active material content.
2Reliability
If insulating material is added to prevent internal short circuit, then conductivity of the negative electrode decreases
Solution Approach 1:
The insulating material is applied locally rather than uniformly throughout the entire electrode. Specifically, the insulating layer is formed on the surface of negative electrode active material particles or at specific interfaces where short circuit risk exists, while the bulk electrode structure maintains its conductive pathways for electron transport, thus balancing short circuit prevention with conductivity preservation.
3Reliability
If insulating material is spot-applied to negative electrode active material particles, then percolation paths are blocked and short-circuit current is limited
Solution Approach 1:
The insulating material is applied in advance to the negative electrode active material particles before electrode assembly. This preliminary coating ensures that the insulating layer is already in place on particle surfaces, creating a protective barrier that prevents percolation path formation. The advance application allows for controlled deposition and uniform coverage, reducing manufacturing variability.
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
This approach effectively prevents short-circuit currents and heat generation in lithium-ion secondary batteries while maintaining the battery's performance, with only a slight increase in electrical resistance, thus enhancing the battery's reliability and safety.
Implementation Method 1
not to develop conductivity by a percolation path throughout the negative electrode active material layer
Data Source
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AI summary
A negative electrode for a secondary battery according to the present invention has a collector and a negative electrode active material layer formed on a surface of the collector and containing negative electrode active material particles. In the negative electrode active material layer, an insulating material is arranged between the negative electrode active material particles so as not to develop conductivity by a percolation path throughout the negative electrode active material layer. It is possible in this configuration to effectively prevent the occurrence of a short-circuit current due to an internal short circuit and the generation of heat due to such short-circuit current flow in the secondary battery while securing the battery performance of the secondary battery.