Lithium Battery Electrode Copolymer Insulating Layer Against Short Circuits
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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 ignition, and manufacturing defects such as electrode fractures and quality deterioration during the production process.
Innovation Solution
An electrode for lithium secondary batteries is designed with an insulating layer containing a copolymer with imide and rubber-based repeating units, which enhances insulation, heat resistance, and peeling resistance, applied to the electrode current collector to prevent short circuits and manufacturing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating layer is applied to the electrode current collector to prevent short circuits, then safety is improved, but device complexity increases
Solution Approach 1:
The insulating layer uses a copolymer comprising a first block with imide groups and a second block with rubber-based repeating units. This composite structure combines the high-temperature stability of imide groups with the flexibility and adhesion of rubber-based units, achieving effective insulation while maintaining manufacturability and preventing short circuits between electrodes.
Solution Approach 2:
The patent specifies precise compositional parameters for the copolymer: the first block content is 5-50 wt% and the second block content is 50-95 wt% based on total copolymer weight. By optimizing these parameter ranges, the insulating layer achieves appropriate balance between insulation performance, flexibility, and manufacturing processability, resolving the contradiction between safety enhancement and device complexity.
2Reliability
If a copolymer with imide and rubber-based repeating units is used in the insulating layer, then insulation and heat resistance are improved, but manufacturing complexity increases
Solution Approach 1:
The patent defines specific content ranges for the copolymer blocks: first block at 5-50 wt% and second block at 50-95 wt%. These parameter specifications ensure the insulating layer has optimal insulation performance while maintaining flexibility and adhesion properties that facilitate manufacturing processes such as coating and drying, thereby resolving the contradiction between improved insulation and manufacturing ease.
Solution Approach 2:
The copolymer structure provides local quality differentiation: the imide-containing first block provides localized insulation and heat resistance, while the rubber-based second block provides localized flexibility and adhesion. This spatial distribution of functional properties within the copolymer enables both high insulation performance and good manufacturability.
3Reliability
If the insulating layer covers the non-coated portion and electrode mixture layer, then short circuit prevention is improved, but manufacturing precision requirements increase
Solution Approach 1:
The insulating layer is formed as a thin film that flexibly covers the non-coated portion and extends onto the electrode mixture layer. The rubber-based second block in the copolymer provides flexibility that allows the thin film to conform to the electrode surface irregularities and coverage requirements without demanding extremely tight manufacturing tolerances, thus resolving the contradiction between short circuit prevention and manufacturing precision.
Solution Approach 2:
The insulating layer is applied in advance to the non-coated portion before final electrode assembly. This preliminary action ensures that the insulating coverage is established early in the manufacturing process, providing a buffer that reduces the precision requirements for subsequent assembly steps while still preventing short circuits.
Data Source
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.