Thermally Triggered Electrical Bypass for Low-Resistance Cell Bridging
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Solution Overview
Problem
Existing electrical bridging devices, such as inverse fuses and bypass diodes, are unsuitable for high-power applications like electric vehicles due to high resistance, power losses, and cost issues, while existing bridging elements face residue problems from insulating material dissolution.
Innovation Solution
An electrical bridging device using a mechanical energy storage device and a reactive layer that triggers an exothermic reaction to create a low-resistance, irreversible connection between conductors, facilitated by a bimetallic element or spring element, with a reactive layer that initiates a solder joint upon activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inverse fuses are used for bridging defective cells, then the entire system can continue functioning after a cell failure, but the high resistance of these fuses leads to power losses of up to 50 W and unacceptable heating
Solution Approach 1:
The invention changes the resistance parameter of the bridging device by using an exothermic reaction to transform the bridging element from a high-resistance state (insulated) to a low-resistance state (conductive). The reactive layer releases heat that melts the insulating material, creating a low-resistance metallic path that can handle high currents with minimal power loss, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The invention utilizes phase transition of the insulating material from solid to liquid (melting) through exothermic reaction. The reactive layer generates heat that melts the insulating material between conductors, transitioning it from an insulating phase to a conductive molten phase, thereby reducing resistance and power losses while maintaining system reliability.
2Reliability
If bypass diodes are used for bridging energy sources, then short-term interruptions in energy generation can be handled, but the unidirectional connection blocks current in the reverse direction preventing recharging
Solution Approach 1:
The invention extracts the unidirectional constraint from the bridging mechanism by using a symmetric exothermic reaction design. The reactive layer is positioned between two conductors and can be triggered to melt the insulating material in either direction, allowing current to flow bidirectionally while still providing reliable bridging during interruptions, thus resolving the contradiction between reliability and adaptability.
3Reliability
If existing bridging elements with insulating material dissolution are used, then bridging of defective components can be achieved, but residues from the insulating material cause problems
Solution Approach 1:
The invention converts the harmful effect of insulating material residues into a benefit by using the exothermic reaction to completely vaporize or eject the insulating material rather than just melting it. The reactive layer generates sufficient heat to eliminate residues entirely, transforming the harmful residue problem into a clean bridging process that maintains reliability without contamination.
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
Enables high-current, low-resistance bridging of defective components in energy storage systems, ensuring system functionality with minimal power loss and cost-effectiveness.
Implementation Method 1
an electrical bridging device comprising at least two electrically insulated electrical conductors which can be electrically connected to each other by triggering an exothermic reaction in a reactive layer arranged above the conductors
Implementation Method 2
The reactive layer is designed to be triggered by a local heat input and, upon triggering, is capable of melting through the insulating material in order to establish an electrical connection
Implementation Method 3
A bridging element with at least one electrically conductive layer is arranged across the two surface areas. This bridging element is designed as a mechanical energy storage device or is connected to a mechanical energy storage device that can be transitioned from a first mechanical state to a stable second mechanical state by thermal activation
Data Source
Figure 1~2
Figure 3~4
AI summary
The present invention relates to an electrical bypass device having two electrical conductors (1, 2) that are electrically insulated from one another and are arranged such that two surface regions of the two conductors (1, 2) are spaced apart from one another by means of a gap. Above the surface regions there is a bypass element (3) having at least one electrically conductive layer (6, 11, 14, 15), which bypass element is in the form of a mechanical energy store (7) or is connected to a mechanical energy store (8). The mechanical energy store (7, 8) is transferable by thermal triggering from a first mechanical state to a stable second mechanical state in which the electrically conductive layer (6, 11, 14, 15) of the bypass element (3) makes electrical contact with the surface regions and hence shorts the two electrical conductors (1, 2). Arranged above the surface regions there is also a reactive element (4) in which an exothermic reaction can be triggered, as a result of which the mechanical energy store (7, 8) transfers to the stable second mechanical state. The proposed bypass device makes it possible, in the triggered state, for high currents to flow given a low series resistance at the same time, and allows permanent, irreversible bypassing of the monitored component.