Spherical Thermal Pressure Relief Device for Hydrogen Vessels
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Solution Overview
Problem
Existing pressure relief devices for high-pressure hydrogen vessels in fuel cell stacks are inefficient due to unpredictable heat transfer and large package size, leading to potential undesired ruptures and increased manufacturing costs.
Innovation Solution
A thermal pressure relief device with a spherical trigger mechanism containing temperature-sensitive material that expands volumetrically, minimizing package size and activation time by using a thermally conductive housing and a movable member that opens when the material reaches a predetermined temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an elongated fragile bulb with ignitable cord is used as a trigger mechanism, then the PRD can be activated remotely, but the package size and volume of temperature sensitive material increase significantly
Solution Approach 1:
The patent extracts and eliminates the ignitable cord and elongated bulb structure, retaining only the essential spherical trigger mechanism containing the temperature-sensitive material. This removal of unnecessary components directly reduces the package size while maintaining the core functionality of remote thermal activation.
Solution Approach 2:
Instead of using an ignitable cord to transfer heat to a remote bulb, the invention inverts the approach by placing the temperature-sensitive material directly in a spherical body that responds to ambient temperature changes. This eliminates the need for heat transfer through a cord and reduces the overall volume required.
2Adaptability or versatility
If an elongated bulb is used as the trigger mechanism, then remote heat transfer is possible, but the activation period becomes unpredictable and may result in undesired rupture
Solution Approach 1:
The ignitable cord is completely removed from the design, eliminating the unpredictable heat transfer mechanism that caused unreliable activation. The spherical trigger mechanism responds directly to ambient temperature changes, providing predictable and reliable activation at the predetermined temperature.
Solution Approach 2:
The spherical trigger mechanism is self-activating based on ambient temperature changes without requiring an external ignitable cord. The temperature-sensitive material within the spherical body automatically responds to thermal conditions, ensuring reliable and predictable activation based solely on the predetermined temperature threshold.
3Reliability
If a large volume of temperature sensitive material is used in an elongated bulb, then the PRD can be activated at the predetermined temperature, but the manufacturing cost and package size increase
Solution Approach 1:
The trigger mechanism uses a spherical body instead of an elongated bulb. The spherical geometry minimizes the volume of temperature-sensitive material required while maintaining effective thermal response. This shape optimization reduces material costs and simplifies manufacturing processes.
Solution Approach 2:
The invention changes the geometric parameters of the trigger mechanism from an elongated shape to a spherical shape. This parameter change optimizes the volume-to-surface-area ratio, reducing the total volume of temperature-sensitive material needed while maintaining reliable activation at the predetermined temperature, thereby lowering manufacturing costs.
4Temperature
If an elongated bulb is used as the trigger mechanism, then the PRD can respond to high temperatures, but the activation period increases and mechanical stability is compromised
Solution Approach 1:
The spherical trigger mechanism provides a more compact and mechanically stable structure compared to an elongated bulb. The spherical geometry distributes thermal stress more evenly and reduces the activation period by minimizing the thermal mass that needs to be heated, while maintaining the ability to respond to high temperatures.
Solution Approach 2:
Changing the shape parameter from elongated to spherical reduces the thermal mass and optimizes heat distribution within the trigger mechanism. This parameter change shortens the activation period by reducing the time required to reach the predetermined temperature, while the spherical structure enhances mechanical stability during thermal expansion and contraction.
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 provides reliable and rapid activation of the pressure relief mechanism, reducing the risk of vessel rupture and minimizing manufacturing costs while maintaining mechanical stability and integrity.
Implementation Method 1
the temperature sensitive material expands volumetrically with an increase in temperature
Data Source
AI summary
A thermal pressure relief device (TPRD) including a housing having a movable member and a retainer disposed therein. The movable member is movable between an open position and a closed position. A trigger mechanism is disposed between the movable member and the retainer. The trigger mechanism holds the movable member in the closed position and includes a substantially spherical shaped body and a temperature sensitive material disposed in the body. The temperature sensitive material volumetrically expands with an increase in temperature until a predetermined temperature is attained and a breakage of the body occurs. When the body of the trigger mechanism breaks, the movable member is displaced from the closed position to the open position, allowing a fluid to flow through the TPRD.