Battery Cell Connector Fuse Design for Short Circuit Protection
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Solution Overview
Problem
Lithium-ion battery cells in electric motor vehicles can experience irreversible damage due to high currents during a short circuit, posing a risk to the entire drive system, as existing cell connectors lack effective mechanisms to instantly disconnect a defective cell and prevent further damage.
Innovation Solution
A cell connector with a fuse featuring a tapered or cutout region between contact ends, designed to interrupt the electrical connection upon a sudden short circuit, and optionally incorporating a convex portion for mechanical vibration compensation and a plastic sheathing for corrosion protection, ensuring the fuse is not compromised by material fatigue or arc formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cell connector without a fuse is used, then the structure is simpler and manufacturing is easier, but the system reliability deteriorates because short-circuit currents can cause irreversible damage to the drive system and interconnected battery cells
Solution Approach 1:
The fuse is extracted as a separate functional element from the cell connector, creating a distinct weakened cross-section region that can be independently designed and positioned. This allows the fuse to be integrated into the connector structure without completely redesigning the entire connector, balancing reliability improvement with manageable device complexity
Solution Approach 2:
The fuse is pre-configured in the cell connector during manufacturing, establishing a predetermined failure point before any short-circuit event occurs. This preliminary preparation ensures that when a short circuit happens, the protective function is immediately activated without requiring additional detection or activation mechanisms, thereby improving reliability while maintaining relatively simple device structure
2Speed
If the fuse is positioned at a point of weakened cross section, then the cell connector can be interrupted instantly during a short circuit, but the mechanical strength of the cell connector deteriorates at that location
Solution Approach 1:
The cell connector is designed with non-uniform cross-sectional properties: a weakened cross-section region with smaller area for the fuse function, and a convex portion with larger cross-sectional area for mechanical strength. This local differentiation allows the fuse to interrupt current quickly while the convex portion provides mechanical reinforcement to prevent premature failure from vibrations and mechanical stresses
Solution Approach 2:
The convex portion acts as a mechanical reinforcement that compensates for the weakened cross-section at the fuse location. By providing additional material and structural support in advance, it cushions the connector against mechanical failures that could otherwise occur at the vulnerable fuse point due to vibrations and mechanical stresses during vehicle operation
3Volume of moving object
If the cutout is positioned in the region of the compensation element, then the structure is more compact, but the mechanical vibration compensation capability deteriorates and material fatigue risk increases
Solution Approach 1:
The cell connector is segmented into distinct functional regions: a convex portion for mechanical vibration compensation and a cutout positioned separately for the fuse function. This spatial segmentation ensures that the compensation element can perform its vibration-damping function effectively while the cutout provides the necessary weakened cross-section for fuse operation, preventing material fatigue at the fuse location
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 effectively prevents further damage to interconnected lithium-ion battery cells and the drive system by instantly interrupting the short-circuit current, while also compensating for vehicle vibrations and providing additional insulation and corrosion protection.
Implementation Method 1
In the event of a brief current flow which is increased owing to a short circuit, disconnection takes place at that point of the cell connector which has a weakened cross section and constitutes a fuse
Implementation Method 2
A further design of the fuse with the additional effect of mechanical vibration compensation in the cell connector can be created by the cell connector having a compensation element in the form of a convex portion
Data Source
AI summary
A cell connector for connecting lithium-ion battery cells of a lithium ion battery includes a body and a fuse.