Fuel Cell Control Mode Switching for Low-Temperature Start-Up
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell systems face challenges in maintaining efficient start-up performance at low temperatures due to excessive water retention, which leads to hydrogen and air supply hindrances and increased risk of freezing, reducing the quantity of hydrogen available for traveling.
Innovation Solution
A fuel cell system that switches from humid power generation control to dry power generation control when the remaining hydrogen quantity reaches a threshold, using a power generation control unit to manage the transition and restrict output, thereby preventing freezing and ensuring sufficient hydrogen for start-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If humid power generation control is used to maintain efficient power generation, then power generation efficiency is improved, but excessive water retention occurs which hinders hydrogen and air supply and causes freezing at low temperatures
Solution Approach 1:
The patent applies dynamic control by switching between humid power generation control and dry power generation control based on the remaining hydrogen quantity. When hydrogen is abundant, humid control maintains high efficiency; when hydrogen is low, dry control prevents water accumulation and freezing, ensuring reliable start-up performance.
Solution Approach 2:
The patent changes the water content parameter in the membrane electrode assembly by switching control modes. Humid control maintains high water content for efficiency, while dry control reduces water content to prevent freezing and supply hindrance, directly addressing the contradiction between efficiency and reliability.
2Reliability
If dry power generation control is used to prevent water accumulation and freezing, then start-up performance at low temperatures is improved, but the quantity of hydrogen used for traveling decreases
Solution Approach 1:
The patent uses periodic switching between humid and dry power generation control based on hydrogen quantity thresholds. This periodic action allows the system to maximize hydrogen utilization during humid control while periodically preventing water accumulation through dry control, optimizing both travel distance and start-up reliability.
3Reliability
If the gas shortage determination threshold value is set to include hydrogen consumed in stoppage period, then start-up performance is ensured, but the quantity of hydrogen available for traveling becomes small
Solution Approach 1:
The patent performs preliminary dry power generation control when hydrogen quantity reaches the threshold before stoppage. This preliminary action removes excess water in advance, ensuring that when the vehicle stops and temperature drops, no freezing occurs. This eliminates the need to reserve additional hydrogen for stoppage-period scavenging, maximizing travel hydrogen availability.
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 increased hydrogen usage during traveling while maintaining desired start-up performance, preventing freezing, and extending the cruising distance of fuel cell vehicles.
Implementation Method 1
a solid polymer electrolyte fuel cell includes a membrane electrode assembly (MEA)... power generation cell (a unit cell) is formed by sandwiching the membrane electrode assembly between separators
Implementation Method 2
The stagnant water is frozen below the freezing temperature
Data Source
AI summary
A fuel cell system includes a fuel cell, an accumulator configured to store a fuel gas, a gas remaining quantity acquisition unit configured to obtain a remaining quantity of the fuel gas stored in the accumulator, and a power generation control unit. When the remaining quantity of the fuel gas stored in the accumulator is decreased to a threshold value, the power generation control unit performs switching from humid power generation control to dry power generation control.