Electrode Assembly Extension Structure for Accurate Gap Measurement
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Solution Overview
Problem
The measurement of the gap between stacked electrodes in secondary batteries is inaccurate due to the uncoated portions on the electrodes, leading to incorrect judgments of defects and limiting the width of these portions, which in turn hinders the improvement of island defects.
Innovation Solution
An electrode assembly design with a first electrode having an extension portion that protrudes outward from its body portion, allowing accurate measurement of the gap between electrodes by using the relative position of this extension and the second electrode, even when the first electrode's edge is covered by the uncoated portion of the second electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the uncoated portion of the electrode is made wider to improve island defects and protect during notching, then the effectiveness in preventing defects is improved, but the accuracy of gap measurement between stacked electrodes deteriorates
Solution Approach 1:
The electrode is segmented into two distinct portions: a body portion with electrode active material and an uncoated portion without electrode active material. This segmentation allows the uncoated portion to serve dual purposes: protecting the electrode during notching and providing a reference edge for accurate gap measurement, while the body portion maintains electrical functionality. The segmentation resolves the contradiction by separating the protective function from the measurement function.
Solution Approach 2:
The uncoated portion acts as an intermediary element between the electrode body and the measurement system. It provides a clean, defined edge that serves as a reference point for gap measurement, mediating between the need for wide protective portions and the need for accurate measurement. The uncoated portion translates the physical structure into a measurable reference without interfering with the protective function.
2Strength
If the uncoated portion is made wider to enhance protection during notching process, then the electrode protection is improved, but the correct judgment of electrode stacking defects deteriorates
Solution Approach 1:
The electrode structure is divided into a body portion and an uncoated portion, where the uncoated portion serves as a dedicated reference element for manufacturing inspection. This segmentation enables the quality control system to distinguish between actual stacking defects and the intentional wide uncoated portions, resolving the contradiction between protection and inspection accuracy.
Solution Approach 2:
The uncoated portion has a visually distinct appearance compared to the body portion with electrode active material. This visual distinction (analogous to color change) allows inspection systems to easily identify the uncoated portion as a reference feature rather than a defect, enabling correct judgment of stacking quality despite the wide uncoated area.
3Reliability
If the uncoated portion width is increased to improve island defects, then the island defect prevention is improved, but the limitation on uncoated portion size worsens the measurement accuracy
Solution Approach 1:
The electrode is segmented into body and uncoated portions, with the uncoated portion serving as a stable reference feature for measurement. This segmentation allows the uncoated portion to be made wide enough to prevent island defects while simultaneously providing a reliable reference edge for accurate gap measurement, resolving the contradiction between defect prevention and measurement accuracy.
Data Source
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AI summary
The present disclosure relates to an electrode assembly, and the electrode assembly according to one aspect of the present disclosure may include a first electrode including a first body portion coated with a first electrode active material and a first tab portion extending outward from an edge of the first body portion; a second electrode including a second body portion stacked on one surface of the first body portion and coated with a second electrode active material, and an uncoated portion provided on an edge of the second body portion and overlapping the edge of the first body portion; and a separator interposed between the first electrode and the second electrode, wherein the first electrode may further include an extension portion provided on the edge of the first body portion and protruding outward from the uncoated portion.