Fuel Cell Unit Relay Cooling via IPM Pipe Proximity
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Solution Overview
Problem
In fuel cell vehicles with the fuel cell unit entirely disposed inside the engine compartment, the combined housing of the fuel cell stack, boost converter, and relay in one case leads to excessive ambient temperature increases, causing the relay's temperature to rise significantly, potentially exceeding safe limits and affecting the stability and lifespan of these components.
Innovation Solution
The fuel cell unit incorporates a cooling system with a first and second cooling pipe configuration, where the relay is positioned closer to the second cooling pipe than the switching element, and bus bars are partially or fully aligned along the cooling pipes to enhance cooling efficiency, thereby suppressing the relay's temperature and maintaining stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the fuel cell stack, boost converter, and relay are housed in one case to save space, then the device complexity is reduced, but the ambient temperature inside the case excessively increases causing the relay temperature to rise significantly
Solution Approach 1:
The patent applies local quality by providing different cooling arrangements for different components within the same housing. Specifically, the relay is positioned closer to the cooling pipe than to the switching element, creating localized cooling zones with different temperature characteristics suitable for each component's thermal requirements.
Solution Approach 2:
The cooling pipe acts as an intermediary element that mediates heat transfer from the switching element. The pipe is strategically positioned to intercept heat from the switching element while also providing a cooling effect to the relay, thus serving as a thermal intermediary that protects sensitive components from excessive heat.
2Volume of moving object
If the relay is positioned closer to the switching element for compact layout, then the housing space is optimized, but the relay temperature increases due to proximity to heat-generating components
Solution Approach 1:
The patent creates localized thermal environments by positioning the relay in a specific location within the housing - closer to the cooling pipe than to the switching element. This spatial arrangement creates a local cooling zone around the relay that maintains its operational reliability while still achieving compact overall housing dimensions.
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
This configuration effectively suppresses excessive temperature increases in the relay and boost converter, ensuring stable operation and extending the lifespan of the fuel cell unit by optimizing the cooling effect and heat management within the compact housing.
Implementation Method 1
a first cooling pipe through which refrigerant to flow into the channel for refrigerant of the cooling component flows and a second cooling pipe through which the refrigerant flowing out of the channel for refrigerant flows
Data Source
AI summary
A fuel cell unit including a fuel cell stack, boost converter, and relay for switching on and off electric power output from the fuel cell stack housed in one case, and capable of avoiding damage from excessive heat generation of the relay as well as suppressing an excessive increase in the ambient temperature inside the case. In the fuel cell unit, a first cooling pipe that delivers refrigerant for cooling to a switching element that forms the boost converter and is provided in an electric power converter IPM and a second cooling pipe that delivers the refrigerant after cooling are provided inside the case. The relay for switching on and off the electric power output from the fuel cell stack is disposed closer to the cooling pipes than to the switching element in the electric power converter IPM. Heat generation of the relay is suppressed by the refrigerant flowing through the cooling pipes and also the relay is not significantly affected by the heat generation of the switching element.