Cylindrical Battery Electrode Insulation at the Winding Cut Area
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Solution Overview
Problem
Cylindrical secondary batteries face the risk of short circuits due to expansion or movement of the negative electrode mixture portion, leading to potential contact between the positive and negative electrode uncoated portions during charging and discharging.
Innovation Solution
A cylindrical secondary battery design with an improved insulating structure that includes an insulating part on the uncoated portions of the electrode plates, formed by applying insulative material to the cutting area between the electrode plates, which prevents short circuits while maintaining a high capacity-to-volume ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating structure is added to prevent short circuits between electrode uncoated portions, then battery safety and reliability are improved, but battery volume increases and capacity-to-volume ratio decreases
Solution Approach 1:
The insulating part is integrated into the separator structure itself, forming a nested configuration where the insulating layer is embedded within the separator's thickness rather than being added as a separate external component. This allows the insulating function to be achieved while minimizing additional volume occupation, thereby maintaining a high capacity-to-volume ratio.
Solution Approach 2:
The insulating part is selectively positioned only at the critical cutting area where the uncoated portions of electrode plates are located, rather than providing insulation throughout the entire separator. This localized approach ensures short circuit prevention at the most vulnerable point while minimizing the overall volume consumed by the insulating structure.
2Stability of the object's composition
If insulating material is applied to prevent short circuits, then electrode assembly stability is improved, but battery weight increases
Solution Approach 1:
The insulating material is integrated within the separator structure, forming a nested configuration where the insulating layer is embedded within the separator's thickness rather than being added as a separate external component. This allows the insulating function to be achieved while minimizing additional weight, thereby maintaining a high capacity-to-weight ratio.
Solution Approach 2:
The insulating material is selectively positioned only at the critical cutting area where the uncoated portions of electrode plates are located, rather than providing insulation throughout the entire separator. This localized approach ensures electrode assembly stability at the most vulnerable point while minimizing the overall weight added by the insulating material.
3Reliability
If a separate insulating part is used to prevent short circuits, then insulation effectiveness is improved, but device complexity and assembly difficulty increase
Solution Approach 1:
The insulating part and separator are merged into a single integrated component, where the insulating layer is formed as part of the separator structure itself. This integration eliminates the need for separate insulating components and simplifies the assembly process, as the insulating function is already built into the separator that is already part of the electrode assembly structure.
Solution Approach 2:
The separator is designed to serve multiple functions simultaneously: it provides ion transport between electrodes, maintains electrode separation, and incorporates an integrated insulating part for preventing short circuits at the cutting area. This multi-functionality reduces the need for additional separate components and simplifies the overall device structure.
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
Disclosed is a cylindrical secondary battery (10) including an electrode assembly (200) including a first electrode plate (210) having a first active material layer and a first uncoated portion free of the first active material layer, a second electrode plate (220) having a second active material layer and a second uncoated portion free of the second active material layer, and a separator (230) interposed between the first electrode plate (210) and the second electrode plate (220), the electrode assembly (200) being wound in a cylindrical shape, an insulating part (700a) provided on one side of each of the first and second uncoated portions, a cylindrical can (100) accommodating the electrode assembly (200), and a cap assembly (600) coupled to one end of the can (100). A part of each of the first and second uncoated portions adjacent to the center of the winding is removed to form a cutting area. The insulating part (700a) is provided in the cutting area.