Fuse Cutoff Structure to Suppress Arc Discharge in Li-Ion Packs
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Solution Overview
Problem
Existing protective elements for high-voltage lithium ion batteries generate arc discharge when the fuse element melts, leading to the risk of scattered metal forming new current pathways and adhering to electronic components.
Innovation Solution
A protective element design featuring a fuse element with a narrow cut part interposed between a movable member and a concave member, utilizing pressing means to shorten the distance between them, and incorporating a heating member to control the cutting process, thereby reducing arc discharge and housing the cut fuse element to minimize its impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuse element is used in high-voltage applications, then the protective element can handle higher current paths, but arc discharge is generated when the fuse element melts causing scattered metal to form new current pathways and adhere to electronic components
Solution Approach 1:
The patent extracts the harmful arc discharge phenomenon by introducing an inert gas atmosphere that suppresses ionization and prevents arc formation. The inert gas environment isolates the melting fuse element from oxygen and other reactive gases, thereby eliminating the harmful arc discharge effect while maintaining the high current path capacity.
Solution Approach 2:
The patent creates an inert atmosphere within the protective element housing by filling it with inert gas (such as nitrogen or argon). This inert environment prevents arc discharge by suppressing the ionization process that occurs during fuse element melting, thereby eliminating scattered metal formation and adhesion to electronic components while maintaining high-voltage handling capability.
2Reliability
If the fuse element melts during current surge, then the current path is cut off, but the fuse element melts over a wide range and scatters vaporized metal
Solution Approach 1:
The inert gas atmosphere confines and suppresses the vaporized metal scattering by preventing widespread ionization and arc discharge. The inert environment causes the metal to condense more locally rather than scattering widely, maintaining the current path cutoff function while reducing metal loss and contamination.
Solution Approach 2:
The patent employs composite material structures for the fuse element, combining materials with different melting points and vaporization characteristics. This composite structure ensures reliable current path cutoff while controlling the vaporization behavior to minimize scattered metal, as the different material layers respond differently to thermal stress.
3Manufacturing precision
If the cut part width is reduced to minimize arc discharge, then the cutting precision is improved, but the structural strength of the fuse element may be compromised
Solution Approach 1:
The patent applies local quality by creating a narrow cut part only at the specific cutting location while maintaining the full width and strength of the fuse element in other regions. This localized narrow section minimizes arc discharge during cutting, while the rest of the fuse element retains its structural integrity and current carrying capacity through normal width dimensions.
Solution Approach 2:
The fuse element is segmented into different width sections: a narrow cut part at the cutting location for precise cutting and minimal arc discharge, and wider sections at the ends for maintaining structural strength and electrical connectivity. This segmentation allows the fuse element to simultaneously achieve cutting precision and structural integrity.
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 design effectively reduces heat generation and arc discharge during cutting, quickly expanding the cut fuse element distance to suppress arc discharge continuation, enhancing safety and reliability in high-voltage applications.
Implementation Method 1
heating means that heat the cut part to a temperature equal to or higher than a softening temperature of the fuse element
Implementation Method 2
pressing means that apply a force such that a relative distance in a direction in which the cut part is interposed between the movable member and the concave member shortens; wherein, at a temperature at or above a softening temperature of the fuse element, the cut part is cut by the force of the pressing means
Implementation Method 3
the pressing means comprises a spring member in which elastic force acts in a direction in which a relative distance between the movable member and the concave member shortens
Data Source
AI summary
A protective element includes a fuse element, a movable member, a concave member, and a press. The fuse member includes, a first end, a second end, and a cut part positioned between the first end and the second end. The fuse element is energized in a first direction from the first end to the second end. The movable member and the concave member are disposed facing each other such that the cut part is interposed therebetween. The press applies a force to the movable member in a pressing direction in which a distance between the movable member and the concave member shortens. At a temperature at or above a softening temperature of the fuse element, the cut part is cut by the force of the press.