Battery Electrode Insulating Copolymer Layer for Short-Circuit Resistance
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to short circuits between electrodes, which can lead to fires and require improvements in manufacturing processability.
Innovation Solution
An electrode for lithium secondary batteries is designed with an insulating layer containing a copolymer with imide and rubber-based repeating units, enhancing insulation, heat resistance, and peeling resistance, applied to the electrode current collector to prevent short circuits and fractures during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional insulating layer is used on the electrode current collector, then the manufacturing process is simple, but short circuits between electrodes occur leading to safety issues
Solution Approach 1:
The insulating layer uses a composite material comprising a copolymer with imide groups and rubber-based repeating units. This composite structure provides both excellent electrical insulation properties to prevent short circuits and enhanced mechanical flexibility to prevent electrode fracture during manufacturing processes.
Solution Approach 2:
The insulating layer's chemical composition is optimized by incorporating specific functional groups (imide groups and rubber-based units) in controlled ratios. The imide content is maintained at 5-50 wt% to balance insulation performance with manufacturing processability, preventing both short circuits and electrode fracture.
2Reliability
If the insulating layer has high insulation performance, then short circuits are prevented, but electrode fracture occurs during manufacturing
Solution Approach 1:
The copolymer combines rigid imide groups for insulation with flexible rubber-based repeating units to maintain electrode flexibility. This composite structure ensures both high insulation performance and resistance to fracture during manufacturing processes such as rolling and stacking.
Solution Approach 2:
The insulating layer exhibits local quality differentiation where imide groups provide insulation at the molecular level while rubber-based units provide flexibility at the macro level. This spatial distribution of functional properties within the copolymer chain resolves the contradiction between insulation and flexibility.
3Reliability
If a thick insulating layer is applied to prevent short circuits, then safety improves, but manufacturing processability deteriorates
Solution Approach 1:
Rather than increasing layer thickness, the solution changes the chemical composition parameters of the insulating layer. The copolymer with specific imide content (5-50 wt%) and rubber-based repeating units provides adequate insulation in a thin layer while maintaining excellent manufacturing processability and preventing electrode fracture.
Data Source
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AI summary
According to an embodiment, an electrode for a secondary battery is provided, the electrode for a secondary battery including: an electrode current collector, and an electrode mixture layer and an insulating layer on at least one surface of the electrode current collector, wherein the insulating layer includes a copolymer, and the copolymer includes a repeating unit having an imide group and a rubber-based repeating unit. According to an embodiment of the present disclosure, it is possible to prevent ignition from occurring in the lithium secondary battery to improve safety.