Fuel Cell Cooling Water Flow Control for Low-Temperature Freeze Prevention
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Solution Overview
Problem
Low-temperature cooling water can flow into a fuel cell and freeze, causing failure in power generation due to inadequate temperature control in existing fuel cell systems.
Innovation Solution
A fuel cell system with a bypass passage and flow control valve, along with a controller that adjusts the cooling water flow rate to prevent low-temperature water from entering the fuel cell, and an ion exchanger to maintain constant electric conductivity, ensuring the fuel cell operates effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling water is circulated through the radiator to cool it, then the cooling water temperature is reduced for effective heat dissipation, but the cooled water may become too cold and freeze in the fuel cell during low ambient temperatures
Solution Approach 1:
The control unit performs preliminary temperature detection of cooling water before it enters the fuel cell. When the temperature is detected to be below the predetermined threshold, the control unit preemptively adjusts the flow control valve to increase bypass flow and reduce radiator flow, preventing the cold water from reaching the fuel cell before damage can occur.
Solution Approach 2:
The bypass passage acts as an intermediary pathway that allows cooling water to circumvent the radiator when temperatures are low. The flow control valve mediates between the radiator pathway and bypass pathway, dynamically routing cooling water through the bypass to prevent excessively cold water from entering the fuel cell while still allowing some cooling function.
2Loss of energy
If the flow rate of cooling water to the radiator is increased to improve cooling efficiency, then heat dissipation performance is enhanced, but the risk of low-temperature water entering the fuel cell increases
Solution Approach 1:
The flow control valve dynamically adjusts the flow rate distribution between the radiator and bypass passages based on real-time temperature conditions. When the cooling water temperature is high, more flow is directed to the radiator for efficient heat dissipation. When the temperature drops below the threshold, the valve dynamically shifts to redirect more flow through the bypass, preventing freezing while maintaining adaptive cooling efficiency.
Solution Approach 2:
The system changes the flow rate parameter dynamically based on temperature conditions. The control unit monitors cooling water temperature and adjusts the flow rate percentage to the radiator accordingly - allowing high flow rates when temperatures are safe for maximum heat dissipation, and reducing radiator flow rate when temperatures approach freezing risk, thereby adapting the cooling parameter to environmental conditions.
3Duration of action of stationary object
If cooling water is continuously circulated to maintain fuel cell temperature, then power generation operation is sustained, but ions in the cooling water can accumulate and reduce insulation performance
Solution Approach 1:
The control unit implements periodic ion removal operation by controlling the pump to circulate cooling water through the ion exchanger at predetermined intervals during continuous power generation. This periodic circulation through the ion exchanger removes accumulated ions from the cooling water, restoring insulation performance while maintaining continuous fuel cell operation between intervals.
Solution Approach 2:
The cooling water circulation system maintains continuous useful action for heat dissipation during power generation, while the periodic ion removal through the ion exchanger ensures that the insulation property is restored regularly. This combination allows continuous operation duration to be extended by periodically eliminating the harmful effect of ion accumulation that would otherwise limit continuous operation.
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
Prevents freezing of cooling water in the fuel cell by controlling the flow rate of cooling water and removing ions, ensuring reliable power generation and insulation.
Implementation Method 1
a radiator provided in the circulation passage to dissipate heat from the cooling water
Implementation Method 2
a pump provided in the circulation passage to pump the cooling water into the fuel cell from the cooling water inlet
Implementation Method 3
a flow control valve provided in the circulation passage to adjust a ratio between the flow rates of the cooling water pumped into the radiator and the bypass passage
Data Source
AI summary
A flow control valve 26 can adjust the percentage of the flow rate of cooling water to a radiator 23 to a predetermined value (50%) or smaller. When the temperature of the cooling water in a fuel cell 11 is determined to be a predetermined temperature (0° C.) or higher after the cooling water is supplied to the fuel cell 11 with the percentage of the flow rate of the cooling water to the radiator 23 set to the predetermined value (50%) or larger, a controller 41 performs a predetermined percentage supply operation for controlling the flow control valve 26 and a pump 22 to supply the cooling water to the fuel cell 11 with the percentage of the flow rate of the cooling water to the radiator 23 set to the predetermined value (50%) or larger.