Stacked Electrode Assembly With Functional Layer Against Short Circuits
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Solution Overview
Problem
Rechargeable batteries face issues with short circuits due to differences in electrode areas, leading to potential damage such as ignition or explosion. Additionally, lithium precipitation occurs on positive electrodes without a facing negative electrode.
Innovation Solution
An electrode assembly is designed with a stacked-type configuration where positive electrodes, separators, and negative electrodes are alternately stacked. The outermost positive electrode features a substrate with an uncoated region and an active material layer on one surface, along with a ceramic layer on the opposite surface. A functional layer is included between the substrate and the active material layer, providing insulation and reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the areas of positive and negative electrodes are made different to optimize battery structure, then battery design flexibility is improved, but short circuit risk increases due to exposed substrate contact with active material layers
Solution Approach 1:
A functional layer is introduced as an intermediary between the substrate and the active material layer. This functional layer acts as an insulating barrier that prevents direct contact between the exposed substrate and the active material layer of different polarity, thereby eliminating the short circuit risk while maintaining the design flexibility of having different electrode areas.
2Device complexity
If the outermost electrode is made as the positive electrode to simplify structure, then manufacturing complexity is reduced, but lithium precipitation occurs on the positive electrode without a facing negative electrode
Solution Approach 1:
The functional layer serves as a mediator between the substrate and the active material layer on the outermost positive electrode. This functional layer prevents lithium precipitation by acting as a barrier that controls lithium ion deposition, allowing the simplified structure with the positive electrode as the outermost electrode while eliminating the harmful lithium precipitation effect.
3Reliability
If current concentration areas are reduced to improve safety, then short circuit risk is reduced, but electrode design flexibility is constrained
Solution Approach 1:
The functional layer is applied selectively in specific locations where current concentration and short circuit risk occur, namely between the substrate and the active material layer in areas where electrodes of different polarity may come into contact. This localized application maintains electrode design flexibility while effectively improving safety by addressing only the critical areas.
Data Source
AI summary
An electrode assembly for a rechargeable battery according may include a stacked-type electrode assembly in which positive electrodes, separators, and negative electrodes are alternately stacked, wherein the positive electrode on an outermost side of the stacked-type electrode assembly, the positive electrode includes a substrate having an electrode uncoated region and an electrode active region, an active material layer formed on one surface of the substrate in the electrode active region, and a ceramic layer formed on the opposite surface of the substrate in the electrode active region, and the one surface is relatively adjacent to the center and faces the negative electrode.