Fuel Cell Hydrogen Supply Apparatus for Cold Start and Voltage Control
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Solution Overview
Problem
Fuel cell stacks experience performance deterioration and voltage drops due to rapid load variations, low humidity, and cold starts, leading to decreased reaction speed, catalyst degradation, and noise issues during hydrogen purging.
Innovation Solution
A hydrogen supply apparatus that includes a hydrogen pipe with a rotating supply pipe and apertures, allowing selective hydrogen supply to the cathode, which also recirculates unreacted hydrogen to prevent voltage drops, recover catalyst performance, and reduce noise during cold starts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hydrogen is supplied to the anode during cold start, then the fuel cell stack temperature increases slowly, but cell voltage drops and reaction speed decreases
Solution Approach 1:
The patent applies preliminary action by supplying hydrogen to the cathode before the fuel cell stack reaches normal operating temperature during cold start. This pre-supply of hydrogen to the cathode enables the electrochemical reaction to proceed even at low temperatures, generating heat to warm the stack while maintaining voltage and reaction speed. The controller detects cold start conditions and activates this alternative hydrogen supply path proactively.
2Power
If the fuel cell stack operates at high power output, then the power generation capacity increases, but performance deteriorates due to high voltage or reverse voltage generation
Solution Approach 1:
The patent implements feedback control by continuously monitoring the voltage across the fuel cell stack and adjusting the hydrogen supply distribution accordingly. When the controller detects high voltage or reverse voltage conditions during high power operation, it activates the hydrogen supply to the cathode to counteract the voltage anomaly and protect the fuel cell performance. This closed-loop control ensures reliable operation at high power outputs.
3Ease of operation
If the polymer electrolyte membrane is in a dry state, then the fuel cell operates in idle state, but mobility of H+ ions is degraded and cell voltage drops
Solution Approach 1:
The patent applies preliminary action by detecting idle state conditions and proactively supplying hydrogen to the cathode to generate water through the electrochemical reaction. This water production humidifies the polymer electrolyte membrane in advance, preventing degradation of H+ ion mobility and avoiding cell voltage drops before they occur.
4Loss of substance
If hydrogen is purged from the fuel cell stack, then unreacted hydrogen is removed, but noise is generated causing driver discomfort
Solution Approach 1:
The patent converts the harmful noise-generating hydrogen purge into a beneficial process by redirecting the purged hydrogen to the cathode. Instead of venting hydrogen through noise-generating exhaust paths, the system channels it to the cathode where it participates in the electrochemical reaction. This eliminates the noise problem while maintaining efficient hydrogen utilization.
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 cell voltage drops, maintains catalyst performance, rapidly increases fuel cell stack temperature during cold starts, and reduces noise from hydrogen purging, enhancing overall fuel cell system efficiency and driver comfort.
Implementation Method 1
Fuel cell systems generate electrical power via an electrochemical reaction, and exhaust heat and water that are by-products of the electrochemical reaction
Implementation Method 2
the hydrogen supplied to the anode is divided into protons (H+) and electrons (e−) by a catalyst of an electrode layer provided at both sides of an electrolyte layer
Implementation Method 3
Only the protons (H+) are selectively transferred to the cathode through the electrolyte layer of the positive ion exchange layer
Implementation Method 4
Simultaneously, the electrons (e−) are transferred to the cathode through the gas diffusion layer and the separating plate
Implementation Method 5
In the cathode, the protons supplied through the electrolyte layer and the electrons supplied through the separating plate have a chemical reaction with oxygen in the air supplied to the cathode by an air supplying apparatus and generate water
Implementation Method 6
a reduction reaction that generates water within an oxygen portion of the cell
Implementation Method 7
Movement of the protons generates a current
Implementation Method 8
heat is generated in a water generating reaction
Data Source
AI summary
A hydrogen supply apparatus of fuel cell stack is provided. In particular, a plurality of unit cells includes a membrane electrode assembly, a separating plate disposed on two sides of the membrane electrode assembly, a coolant path, an air path, a fuel path, and an air inlet manifold communicated with the air path. An end plate is disposed on each end of the plurality of unit cells and forms an air inlet manifold in a location corresponding to the air inlet manifold of the separating plate. Additionally, a hydrogen supply apparatus is provided in the air inlet manifold of the separating plate and the air inlet manifold of the end plate that selectively supplies additional hydrogen to the cathode through the air path when needed.