Lithium-Ion Electrode Groove Layout for Metal Impurity Detection
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Solution Overview
Problem
In lithium-ion secondary batteries with grooves in the positive or negative electrode active material layers, it is difficult to determine the presence of metal impurities using insulation inspection tests due to reduced contact area between metal impurities and electrodes.
Innovation Solution
A lithium-ion secondary battery design where at least one of the electrode active material layers has a groove, with a conductive layer on the separator surface facing the groove, facilitating easier detection of metal impurities during insulation inspection tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a groove is formed in the electrode active material layer to facilitate electrolyte penetration, then the battery performance is improved, but the contact area between metal impurities and the electrode is reduced, making insulation inspection difficult
Solution Approach 1:
A conductive layer is introduced as an intermediary between the groove and the electrode active material layer. This conductive layer fills the groove and provides a continuous conductive path from the groove to the electrode, enabling effective insulation inspection while maintaining the groove's beneficial effects on electrolyte penetration and battery performance
Solution Approach 2:
The conductive layer extends the detection path from a two-dimensional surface contact to a three-dimensional volume that includes the groove depth. By filling the groove with conductive material, the inspection test can detect metal impurities through the vertical dimension of the groove, not just at the surface level
Data Source
AI summary
A lithium-ion secondary battery includes: an electrode body in which a positive electrode having a positive electrode active material layer and a positive electrode current collector, and a negative electrode having a negative electrode active material layer and a negative electrode current collector, are laminated with a separator therebetween, the separator having a conductive layer, wherein: the positive electrode active material layer and the negative electrode active material layer contact the separator, at least one of the positive electrode active material layer or the negative electrode active material layer has a groove in a thickness direction, and a surface of the separator, which faces a surface of the at least one of the positive electrode active material layer or the negative electrode active material layer which has the groove, includes the conductive layer.