Fuel Cell Thermal Trigger Using SMA Wire for Remote Gas Evacuation
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Solution Overview
Problem
High-pressure hydrogen fuel cell systems require a reliable remote trigger device for thermal safety devices to quickly detect dangerous conditions and initiate gas evacuation, with existing solutions facing challenges in operational reliability and large-scale production economy.
Innovation Solution
A remote trigger device for a fuel cell automotive system, comprising a thermal safety device with a breakable temperature-sensitive bulb and an auxiliary device that uses a shape-memory material wire to activate the gas evacuation when the temperature exceeds a threshold, eliminating the need for tensioned SMA wire and reducing stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tensioned SMA wire is used in the remote trigger device, then the shape memory effect can activate the thermal safety device, but the wire is subject to vibrations and fatigue stresses that reduce operational reliability
Solution Approach 1:
The patent removes the tensioned SMA wire from the system entirely. Instead of using a tensioned wire that connects the remote trigger to the thermal safety device, the invention uses a compressible element (spring) that is compressed during assembly and releases to activate the thermal safety device when triggered, eliminating the wire and its associated fatigue and vibration problems
Solution Approach 2:
The patent replaces the mechanical tensioned wire system with a compression-based spring mechanism. The spring is compressed during assembly and stores potential energy, which is then released to activate the thermal safety device, substituting the tensile mechanical system with a compressive one that is more reliable under vibration and fatigue conditions
2Measurement precision
If elastic compensating elements are used to compensate for SMA wire elongation, then temperature threshold detection can be maintained, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the elastic compensating elements from the system. By eliminating the tensioned SMA wire entirely and using a compression spring mechanism instead, there is no wire elongation to compensate for, thus eliminating the need for elastic compensating elements and reducing device complexity
Solution Approach 2:
The compression spring serves multiple functions: it provides the activating force for the thermal safety device and inherently compensates for any dimensional variations through its compression characteristics, eliminating the need for separate compensating elements
3Ease of operation
If a remote trigger device with tensioned SMA wire is used, then gas evacuation can be initiated remotely, but the stress on components reduces operational reliability and increases manufacturing difficulty
Solution Approach 1:
The patent removes the tensioned SMA wire and associated tensioning mechanisms, simplifying the manufacturing process. The compression spring mechanism is easier to manufacture and assemble, as it eliminates the need for precise tensioning and compensation mechanisms
Solution Approach 2:
The patent changes the fundamental operating parameter from tension to compression. The spring is compressed during assembly to a predetermined force, and this compression state is maintained until activation, providing a more manufacturable and reliable system than tensioned wire mechanisms
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 operational reliability by ensuring immediate gas evacuation with reduced stress on components, simplifying manufacturing, and avoiding the need for elastic compensating elements, thus improving safety and production efficiency.
Implementation Method 1
an auxiliary device that uses a shape-memory material wire to activate the gas evacuation when the temperature exceeds a threshold
Implementation Method 2
a thermal safety device with a breakable temperature-sensitive bulb
Data Source
AI summary
A trigger device for a thermal safety device of a fuel cell automotive system which has a stop, a heat sensitive element consisting of a wire made of shape-memory material, and a trigger abutment is provided. In an intermediate configuration of the trigger device, a distal end of the heat sensitive element is freely slidable by shortening of the heat sensitive element. In an activation configuration of the trigger device, in which temperature perceived by a heat sensitive section of the heat sensitive element is above or equal to an activation temperature, the distal end abuts against the trigger abutment so that a proximal end of the heat sensitive element moves the stop to bring the thermal safety device into a remote emergency configuration.