Extended Electrode Tab Center Pin for Cylindrical Lithium Ion Battery
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Solution Overview
Problem
Conventional cylindrical lithium ion secondary batteries require a separately fabricated and inserted center pin, which increases manufacturing costs and risks deformation or fracture of safety vents upon impact.
Innovation Solution
The electrode tab is extended to serve as a center pin, eliminating the need for a separate center pin, with the tab being welded to an uncoated region of the electrode plate and designed to function as a heat sink, providing structural support and heat release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate center pin is fabricated and inserted into the electrode assembly, then the electrode assembly can be prevented from deformation and gas can be discharged, but the manufacturing cost increases and additional insertion steps are required
Solution Approach 1:
The electrode tab is extended to serve dual functions: as an electrical conductor and as a center pin for structural support and gas discharge. This merging of functions eliminates the separate center pin component and its associated fabrication and insertion steps, directly resolving the contradiction between reliability and manufacturing complexity
Solution Approach 2:
The extended electrode tab performs multiple functions simultaneously: electrical connection, structural support preventing electrode assembly deformation, and gas discharge pathway. This multi-functionality eliminates the need for a separate center pin while maintaining all necessary functions, addressing both reliability and manufacturing simplicity
2Reliability
If a separate center pin is used, then gas discharge function is provided, but the center pin may come out during impact and strike the safety vent causing deformation or fracture
Solution Approach 1:
By merging the center pin function with the electrode tab, the gas discharge pathway becomes integrated into the electrode structure itself. The extended tab remains firmly attached to the electrode plate, eliminating the risk of detachment and subsequent safety vent damage while maintaining gas discharge functionality
Solution Approach 2:
The extended electrode tab design proactively prevents the harmful effect of center pin detachment by making the tab an integral part of the electrode structure. This preliminary design choice eliminates the possibility of the center pin coming out during impact, thereby preventing safety vent damage before it can occur
3Ease of manufacture
If electrode tab width is extended to serve as center pin, then manufacturing cost and steps are reduced, but the tab must be welded to uncoated region requiring precise positioning
Solution Approach 1:
The electrode plate design includes a specific uncoated region where the electrode tab is welded. This local modification creates a dedicated welding zone with appropriate material properties, facilitating reliable attachment while maintaining precise positioning. The uncoated region serves as a predetermined attachment zone that simplifies the welding process and ensures accurate tab placement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design reduces manufacturing costs and steps, enhances safety by preventing the center pin from striking the safety vent, and maintains battery capacity while ensuring effective gas discharge and heat management.
Implementation Method 1
the electrode tab also serves as a center pin and has a heat release function
Implementation Method 2
the electrode tab which is positioned at the center of a jelly-roll type structure of an electrode assembly is extended so that the electrode tab also serves as a center pin and has a heat release function
Implementation Method 3
the width of an electrode tab which is positioned at the center of a jelly-roll type structure of an electrode assembly is extended so that the electrode tab also serves as a center pin
Implementation Method 4
the center pin is inserted through the center of the electrode assembly so as to prevent the deformation of the electrode assembly, and so as to quickly discharge, to the top side of the battery (i.e., toward the cap assembly), the gas which is produced within the battery due to heat or the like
Data Source
AI summary
In a cylindrical lithium ion secondary battery, the width of an electrode tab positioned at a center of an electrode assembly is extended so that it serves as a center pin and functions to release heat. Thus, it is not necessary to separately insert a center pin, thereby reducing the manufacturing cost and steps. The cylindrical lithium ion secondary battery comprises an electrode assembly, a case for receiving the electrode assembly, and a cap assembly for sealing the top opening of the case. The electrode assembly comprises a positive electrode plate and negative electrode plate. The positive electrode plate has a positive electrode tab, a positive active material region, a positive uncoated region, and a positive current collector exposed through the positive uncoated region. The negative electrode plate has a negative electrode tab, a negative active material region, a negative uncoated region, a negative current collector exposed through the negative uncoated region, and a separator interposed between the positive and negative electrode plates. At least one of the positive and negative electrode tabs has an extended width at the center of the electrode assembly.