Secondary Battery Fuse Lead Tab Design
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Solution Overview
Problem
Conventional secondary batteries with polygonal shapes face challenges in providing a discharging structure or current shutting off mechanism to manage increased internal pressure, leading to safety risks and instability.
Innovation Solution
Incorporating a lead tab with a fuse part that has excellent mechanical strength and is designed to break when excessive current flows, interrupting the current path and preventing deformation due to external forces, while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a polygonal-shaped secondary battery is used, then the battery can accommodate higher internal pressure, but it becomes difficult to provide a discharging structure or current shutting off structure
Solution Approach 1:
The fuse part is integrated directly into the lead tab structure, merging the current conduction function with the current interruption function. This eliminates the need for separate discharging structures or current shutting off mechanisms, thereby reducing device complexity while maintaining the ability to handle high internal pressure in the polygonal battery configuration
Solution Approach 2:
The fuse part is designed to automatically interrupt excessive current flow through its own structural response to internal pressure and current heat, without requiring external control systems. This self-service mechanism simplifies the overall battery structure while ensuring safety under high pressure conditions
2Reliability
If a lead tab with fuse part is designed to interrupt excessive current, then safety is enhanced, but the lead tab may deform under external force
Solution Approach 1:
The lead tab is designed with non-uniform cross-sectional area along its length, with the fuse part having a reduced cross-sectional area compared to other portions. This local quality variation allows the fuse part to be the weakest link that breaks under excessive current or pressure, while the stronger portions maintain mechanical integrity and resist deformation under external forces
Solution Approach 2:
The lead tab is segmented into distinct functional portions: a stronger terminal junction part for electrical connection, a weakened fuse part for current interruption, and a stronger electrode assembly-junction part for structural support. This segmentation allows each portion to be optimized for its specific function, ensuring both safety and mechanical strength
3Reliability
If the fuse part extends at an angle other than zero, then current interruption is improved, but manufacturing precision requirements increase
Solution Approach 1:
The fuse part is designed with an asymmetric angular extension relative to the longitudinal extension line of the lead tab, rather than extending parallel to it. This asymmetric configuration improves current interruption effectiveness by optimizing the breakage pattern and current path separation, while the angle is designed to be achievable within standard manufacturing tolerances
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
The solution enhances the stability and safety of the secondary battery by effectively shutting off excessive current flow and preventing deformation, thereby reducing the risk of explosion or ignition.
Implementation Method 1
a fuse part electrically connected between the terminal-junction part and the electrode assembly-junction part, the fuse part being configured to break when the first and second terminals are electrically connected
Data Source
AI summary
A secondary battery includes an electrode assembly in a case, the electrode assembly including a positive electrode, a negative electrode, and a separator, a cap assembly connected to the case and including a cap plate, first and second terminals through the cap plate, and a shorting member selectively connecting the first terminal and the cap plate, and at least one electrode lead tab including a terminal-junction part electrically connected to a terminal, an electrode assembly-junction part electrically connected to an electrode in accordance with the terminal, and a fuse part electrically connected between the terminal-junction part and the electrode assembly-junction part, the fuse part being configured to break when the first and second terminals are electrically connected, and the fuse part extending at an angle other than zero with respect to a longitudinal extension line of the terminal junction part and/or the electrode assembly-junction part.