Fuel Cell Evaporative Cooling via Negative Pressure
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Solution Overview
Problem
Conventional fuel cell systems face challenges in efficiently cooling the fuel cell stack and humidifying the air without using separate cooling loops or humidifiers, particularly due to issues with coolant freezing and energy consumption during cold start-ups.
Innovation Solution
A fuel cell system utilizing evaporative cooling, where a cooling channel on the bipolar plate separates from the air and hydrogen channels, with an air compression means creating negative pressure to evaporate water and absorb heat, thus cooling the stack while humidifying the air with a single air line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separate cooling loop is used to cool the fuel cell stack, then the cooling function is provided, but the system complexity increases and energy consumption increases
Solution Approach 1:
The patent combines the cooling function with the air supply function by integrating the cooling channel with the air channel structure. The air line serves dual purposes: supplying oxygen to the cathode and cooling the fuel cell stack through evaporative cooling, thereby eliminating the need for a separate cooling loop and reducing system complexity
Solution Approach 2:
The air line is designed to perform multiple functions simultaneously: it supplies oxygen to the cathode for electrochemical reaction and provides cooling to the fuel cell stack through the cooling channel. This multi-functional design reduces the number of separate systems needed
2Quantity of substance
If a separate humidifier is used to humidify the air, then the air humidification function is provided, but the system complexity increases and energy consumption increases
Solution Approach 1:
The patent merges the humidification function with the cooling function by injecting water into the air stream within the cooling channel. The same air line that cools the stack also humidifies the air, eliminating the need for a separate humidifier
Solution Approach 2:
The cooling channel serves dual functions: it cools the fuel cell stack through evaporative cooling and simultaneously humidifies the air passing through it. This multi-functional approach provides both cooling and humidification without requiring separate systems
3Device complexity
If evaporative cooling is used with negative pressure, then cooling and humidification are achieved with a single air line, but water injection control is required
Solution Approach 1:
The system uses the suction force generated by the air compressor itself to create negative pressure in the cooling channel, eliminating the need for an additional vacuum pump or pressure control system. The air compressor serves its primary function while automatically providing the pressure condition needed for evaporative cooling
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 approach allows for simultaneous cooling and humidification of the fuel cell stack without separate cooling loops or humidifiers, reducing energy consumption and simplifying the system, while maintaining heat and water balance.
Implementation Method 1
Water is evaporated while air and water pass through the cooling channel in a state where an internal pressure of the cooling channel is maintained at a negative pressure by the suction force of the air compression means and, at the same time, heat generated from the fuel cell stack is absorbed by latent heat of evaporation
Implementation Method 2
heat generated from the fuel cell stack is absorbed by latent heat of evaporation, thus cooling the fuel cell stack
Implementation Method 3
an internal pressure of the cooling channel is maintained at a negative pressure by the suction force of the air compression means
Data Source
AI summary
The present invention provides a fuel cell system using evaporative cooling that generates electricity by reacting hydrogen as a fuel and air as an oxidant. The system includes a fuel cell stack including a cooling channel provided on a bipolar plate separately from an air channel and a hydrogen channel, an air inlet line connected to an inlet side of the cooling channel of the fuel cell stack, a water injection means provided at the inlet side of the cooling channel to inject water into air introduced to the cooling channel through the air inlet line, and an air compression means provided at the rear of the fuel cell stack and connected to a discharge line coupled to an outlet side of the cooling channel to provide a suction force to the cooling channel and to compress a mixture of air and water vapor sucked from the cooling channel. The present system provides advantages in that the configuration of the fuel cell system is simplified, lightweight, and downsized, and the manufacturing cost is reduced.