Electrode Plate End-Face Insulation for Internal Short Prevention
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Solution Overview
Problem
Lithium ion batteries face safety hazards due to the risk of internal short circuits between electrode plates of opposite polarities, which increases the likelihood of fires as energy density increases.
Innovation Solution
An electrode plate design featuring a current collector with a main body and tabs, where insulating portions are formed on the end faces to prevent direct contact between plates of opposite polarity, using polymers and ceramics to enhance insulation and protect the end faces during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating portions are formed on the end faces of the current collector, then the safety performance is improved by preventing internal short circuits, but the device complexity increases due to additional coating and processing steps
Solution Approach 1:
The insulating coating is applied to the end faces of the current collector before tab processing. This preliminary action ensures that the insulating portions are already in place before any cutting or processing that might expose new end faces, eliminating the need for additional post-processing insulation steps and reducing overall device complexity.
Solution Approach 2:
The insulating coating process is merged with the existing manufacturing process flow, combining the insulation function with the tab processing operation. By applying the insulating coating to both the main body portion end faces and the tab end faces in a single integrated process, the patent reduces the number of separate steps required, thereby reducing device complexity while maintaining safety performance.
2Ease of manufacture
If the end face of the current collector is directly exposed during cutting and tab processing, then the manufacturing process is simplified, but the risk of internal short circuit increases due to direct contact between opposite polarity electrodes
Solution Approach 1:
The insulating coating is applied to the end faces before any cutting or tab processing operations. This preliminary protective action ensures that even when end faces are exposed during manufacturing, they remain insulated and cannot cause short circuits, thus maintaining ease of manufacture while eliminating the harmful effect.
Solution Approach 2:
The insulating coating acts as an intermediary layer between the conductive current collector end faces and the electrolyte solution. This intermediary prevents direct electrical contact between opposite polarity electrodes, thereby eliminating the internal short circuit risk while allowing the manufacturing process to proceed without additional complexity.
3Manufacturing precision
If a polymer with melting point of 80°C-300°C is used for the insulating portion, then the insulating portion can be melted and cured during tab processing to densely coat the end face, but the manufacturing precision requirements increase to control the melting and curing process
Solution Approach 1:
The patent utilizes the melting point parameter of the polymer (80°C-300°C) to enable phase change during tab processing. By controlling the temperature parameter within this range, the insulating coating melts and flows to densely coat the end faces, automatically achieving high coating density without requiring complex external coating equipment or precise application control.
Solution Approach 2:
The insulating coating material itself provides the curing mechanism through its melting and solidification properties. During tab processing, the heat generated or applied causes the polymer to melt, flow into gaps and crevices on the end faces, and then cure to form a dense coating. This self-service mechanism eliminates the need for separate coating equipment or complex external control systems, thereby reducing processing control complexity while achieving high manufacturing precision.
Data Source
AI summary
Provided are an electrode plate and a secondary battery having the same. The electrode plate comprises a current collector and an active material layer, wherein the current collector comprises a main body portion and tabs, the active material layer is coated on the surface of the main body portion, and the tabs extend from one end of the main body portion along the first direction; a first insulating portion is formed on the end face of the main body portion that is provided with the tabs, and a second insulating portion different from the first insulating portion is formed on the end faces of the main body portion that are not provided with the tabs. The electrode plate of the present application has a good end-face insulation protection and can improve the safety performance of the secondary battery.