Electrode Assembly Coating Layout to Prevent Short Circuits
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Solution Overview
Problem
Conventional electrode assemblies are prone to short circuits and overhang reversal phenomena due to contact between the positive electrode mixture layer and the negative electrode sheet during the lamination process, leading to potential safety issues and lithium deposition.
Innovation Solution
An electrode assembly with a short circuit prevention coating portion is designed, featuring a shoulder portion on the negative electrode sheet that extends vertically to match the positive electrode mixture layer, wrapped with an insulative coating to prevent contact and misalignment, thereby inhibiting short circuits and overhang reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the positive electrode mixture layer is formed on the positive electrode tab extension area and inclined portion, then the electrode assembly can be manufactured, but short circuit may occur due to contact with the negative electrode sheet during lamination
Solution Approach 1:
An insulative coating layer is applied to the positive electrode tab extension area and inclined portion to act as an intermediary barrier. This coating layer prevents direct contact between the positive electrode mixture layer and the negative electrode sheet, eliminating the short circuit risk while allowing the manufacturing process to proceed normally.
Solution Approach 2:
The insulative coating is applied selectively only to the extension area and inclined portion of the positive electrode tab where the mixture layer is formed, rather than coating the entire tab. This localized approach provides the necessary insulation precisely where the short circuit risk exists while maintaining the electrical conductivity of other tab portions.
2Ease of manufacture
If the positive electrode mixture layer is formed on the positive electrode tab extension area and inclined portion, then the electrode assembly can be manufactured, but overhang reversal phenomenon may occur causing lithium deposition
Solution Approach 1:
The insulative coating layer serves as a visual and physical guide during the lamination process. It clearly delineates the boundary of the positive electrode tab area, helping operators maintain precise alignment and prevent overhang reversal, thereby ensuring accurate positioning without compromising manufacturing ease.
3Reliability
If a coating portion is formed on the negative electrode sheet to prevent short circuit, then safety is improved, but the device complexity increases
Solution Approach 1:
The insulative coating acts as a simple intermediary layer that prevents short circuits between electrodes. This straightforward solution improves safety without significantly complicating the device structure, as the coating is a standard manufacturing addition rather than a complex mechanical or electrical component.
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 prevents short circuits and overhang reversal, enhancing safety by ensuring insulation and maintaining the correct capacity ratio between electrodes, thus preventing lithium deposition.
Implementation Method 1
a coating portion, configured to prevent the occurrence of short circuit due to contact between a positive electrode mixture layer formed on a positive electrode tab and a negative electrode sheet
Data Source
AI summary
The present invention relates to an electrode assembly having a short circuit prevention coating portion, and more particularly an electrode assembly including a positive electrode sheet having a positive electrode tab protruding from one side thereof and a positive electrode mixture layer applied to a lower part of the positive electrode tab and to a current collector, a negative electrode sheet having a negative electrode tab protruding from one side thereof and a negative electrode mixture layer applied to a lower part of the negative electrode tab and to a current collector, and a separator located between the positive electrode sheet and the negative electrode sheet, wherein the negative electrode sheet has a shoulder portion extending in a horizontal direction by a predetermined length, the negative electrode active material being applied to the shoulder portion, and the shoulder portion is wrapped with a coating portion.