Inside the Hydrogen Fuel Cell:
Optimizing Air Supply and Thermal Management for Reliability
Reading time: 15 minutes
Article Summary
- Hydrogen fuel cell design and innovation: Showcases Spectronik’s approach to hydrogen fuel cell development, highlighting its mission to deliver portable, efficient, and sustainable fuel cells for diverse electric mobility applications.
- Thermal management with advanced fan systems: Explores how optimal fuel cell temperature is maintained through the use of PWM-controlled fans and temperature sensors, preventing overheating and ensuring consistent performance.
- Air supply management for optimal oxidant delivery: Explains the air supply strategies that ensure stable oxygen flow for efficient fuel cell reactions, including precise blower selection and stoichiometric control to optimize chemical conversion and energy output.
1. Introduction: What are Hydrogen Fuel Cells?
Definition of Hydrogen Fuel Cells
Hydrogen fuel cells are electrochemical devices that generate electricity by combining hydrogen and oxygen, producing only water and heat as by-products.
In a hydrogen fuel cell:
2H₂ + O₂ → 2H₂O + Electric Energy + Heat
Background of Hydrogen Fuel Cells
They are one of the most promising clean energy technologies today, offering zero emissions, high energy density, and versatile applications. While the concept of converting hydrogen and oxygen into electricity has been around for decades, the technology is still evolving, creating both immense opportunities for innovation and unique challenges for developers.
Spectronik: Advancing Hydrogen Fuel Cell Accessibility
Singapore-based Spectronik aims to make hydrogen fuel cell technology accessible for a wide range of electric platforms, including fuel cell electric vehicles (FCEVs), drones, and light electric transport.
The company’s flagship Protium Series is deployed in over 38 countries, supporting applications across air, land, sea, and rail. Designed to be compact and portable, these fuel cells enable flexible integration into diverse systems and operating environments.
Spectronik places strong emphasis on sustainability and product life cycle efficiency. Its fuel cells are:
- Over 90% reusable and recyclable, reducing embodied carbon
- Refurbishable at the local point of use, extending product life
- Zero-emission and performance-optimised, providing the advantages of hydrogen fuel cells over battery-powered alternatives and supporting cleaner mobility solutions.
The technology also integrates fuel cell air management systems and advanced fuel cell thermal management, ensuring reliable operation in a variety of conditions — a key factor when comparing hydrogen fuel cell cars vs electric cars in terms of range, efficiency, and sustainability.
All systems are designed and manufactured in Singapore, ensuring consistent quality, reliability, and innovation.
2. How Does a Hydrogen Fuel Cell Work?
2H₂ + O₂ → 2H₂O + Electric Energy + Heat
- Anode – The negative electrode where hydrogen gas (H₂) enters. At the anode, hydrogen molecules are split into protons (H⁺) and electrons (e⁻).
- Proton Exchange Membrane (PEM) – A special membrane that only allows hydrogen protons (H⁺) to pass through, forcing the electrons to travel through an external circuit, which generates electricity to power a load.
- External Circuit – The path through which electrons flow from the anode to the cathode, producing usable electrical energy.
- Cathode – The positive electrode where oxygen (O₂) enters. Here, the protons (H⁺) from the anode, the electrons (e⁻) from the external circuit, and oxygen combine to form water (H₂O) as the only by-product.
Top advantages of Hydrogen Fuel Cells: Lithium Battery VS Hydrogen
- Energy Density: With an energy density of roughly 33 kWh per kilogram, hydrogen offers about 150 times more energy per unit of mass than today’s lithium-ion batteries.
- Refueling vs. Recharging: Hydrogen fuel cells are refueled by connecting a hydrogen nozzle to the tank, allowing gas to flow in rapidly under high pressure. This process takes just a few minutes, compared to lithium-ion batteries. Energy is stored in lithium-ion batteries by driving lithium ions into the anode and supplying electrons from the charger, creating chemical potential that can be released later.
3. Thermal Management for Hydrogen Fuel Cells
Why is Thermal Management Important for Hydrogen Fuel Cells?
Hydrogen fuel cells generate heat as a byproduct of their chemical reactions. They are typically around 50% efficient, meaning that roughly half of the energy released is converted into electricity, while the other half is released as heat. For example, the Spectronik Protium-1000 (air-cooled fuel cell) delivers 1000 W of electrical power, producing a similar amount of heat in the process.
Effective thermal management is essential to maintain optimal performance:
- Maintain cell hydration
- Preserve proton conductivity
- Ensure consistent fuel cell efficiency and overall performance
Without proper heat removal, the cell can overheat, reducing efficiency and potentially shortening its lifespan. In extreme situations, as safety systems are often in place to prevent the below events from occurring, inadequate cooling can lead to:
- Material degradation
- System malfunctions
- Hydrogen leaks
- Fire or explosion hazards
How ebm‑papst’s AxiForce 80 supported Spectronik’s innovative efforts
Before selecting the ideal fan for heat removal, the airflow requirement must first be determined. Using the Protium-1000 fuel cell as an example:
- The Protium-1000 produces approximately 1000 W of heat.
- The specific heat capacity of air (Cp) is 1005 J/kg·K.
- Hot air exiting the fuel cell is 52.5°C.
- Ambient temperature is 35.0°C.
- Therefore, the temperature difference (ΔT) is: 17.5°C.
Heat removal equation:
W = Cp × m × ΔT
P = Cp × ṁ × ΔT
Rearranging to find mass flow rate:
ṁ = P / (Cp × ΔT)
= 1000 / (1005 × 17.5)
= 0.0569 kg/s
Density of air (ρ) = 1.225 kg/m³
Volumetric flow required:
V̇ = ṁ / ρ
= 0.0569 / 1.225
= 0.0464 m³/s
= 167 m³/h
The estimated pressure drop across the Protium-1000 system is approximately 200 Pa.
The AxiForce 80 provides the following benefits in thermal management:
- Meets required airflow: Able to deliver 167 m³/h at 200 Pa to remove the heat load effectively.
- Buffer capacity: Two AxiForce 80 units are used in the Protium-1000.
- This provides redundancy and cooling headroom.
- Fans operate at roughly half of maximum speed, improving reliability and service life.
- Buffer capacity: Two AxiForce 80 units are used in the Protium-1000.
- PWM Control: Cooling is adjusted dynamically based on real-time stack temperature.
- Two embedded sensors measure the actual stack temperature.
- The MCU adjusts fan speed via PWM according to the difference from the target temperature.
- This is regulated by the fuel cell’s PID controller for stable thermal management.
- Instant speed response: The fans can ramp up or down quickly.
- Maintains optimal stack temperature in varying ambient conditions.
- Minimizes parasitic power consumption when less cooling is needed.
- Tachometer signal for fault detection: Useful in larger systems such as the Protium-3000, which uses up to six fans.
- The tacho signal allows the MCU to monitor each fan individually.
- If a fan fault occurs, the system alerts the user via the GUI to prevent hot spots and thermal stress.
- IP68 certified: Reliable cooling performance in light rain without risk of fan damage — addressing issues seen with non-IP68 fan alternatives.
Working closely with ebm‑papst SEA in Singapore allowed Spectronik to fine-tune the cooling setup for the Protium-1000 and Protium-3000 and validate that the AxiForce 80 could meet its performance needs in practical conditions. This collaboration helped streamline the thermal management approach without adding complexity or maintenance burden. Building on that outcome, Spectronik has since evaluated ebm‑papst fan solutions for the oxidant supply side as well.
4. Air Supply Management for Hydrogen Fuel Cells
Why is Air Supply Management Important for Hydrogen Fuel Cells?
Hydrogen fuel cells rely on the reaction 2 H₂ + O₂ → 2 H₂O, meaning the oxygen supply must be carefully matched to the hydrogen input. Since oxygen is 20% of air, the actual air flow required is much higher than the hydrogen flow, typically 2.5× for stoichiometric balance.
Proper air supply management is essential to maintain optimal performance:
- Ensure sufficient oxidant is available for the chemical reaction, maintaining consistent power output
- Maintain uniform temperature and gas distribution across the stack, avoiding hot spots and performance loss
- Provide operational flexibility, allowing the system to respond to varying load conditions
How ebm‑papst’s RVE45 supported Spectronik’s innovative efforts
The RVE45 provides the following benefits in air supply management:
- Matches stoichiometric requirements: The minimum air requirement is 2.5× the hydrogen flow based on the stoichiometric ratio, and the RVE45 can easily meet this. For Spectronik, the aim is to supply 2–3× the stoichiometric ratio, meaning the total air flow is 5–7.5× the hydrogen flow, which helps maintain consistent performance under varying loads.
- Optimal flow for largest fuel cell: The largest hydrogen fuel cell consumes 40 L/min of hydrogen, so the air requirement is 200–300 L/min. The RVE45’s optimal operating point of 200 L/min meets this need, while its maximum flow rate of 466 L/min provides a comfortable buffer for higher-demand situations. In addition, the fuel cell is equipped with two RVE45 units, providing added buffer and redundancy. Their placement on the left and right sides of the fuel cell also helps ensure a uniform oxidant supply.
- Maintains safe and efficient operation: Supplying 2–3× the stoichiometric ratio ensures consistent oxidant availability and prevents oxidant starvation, supporting stable fuel cell performance.
Careful consideration of air supply requirements and the capabilities of the RVE45 blower by ebm‑papst ensures that hydrogen fuel cells receive the correct oxidant flow to operate efficiently and reliably. By supplying 2–3× the stoichiometric ratio, the system maintains consistent performance under varying loads while preventing oxidant starvation. This approach provides a robust and flexible solution for fuel cell operation, supporting both efficiency and long-term operational stability.
5. Conclusion
Hydrogen fuel cells hold immense promise for a zero-emission future, particularly in fuel cell electric vehicles (FCEVs) and other hydrogen-powered cars. However, optimizing fuel cell thermal management and the fuel cell air management system is critical to unlocking their full potential.
Through the collaboration between Spectronik and ebm‑papst, portable fuel cells like the Protium Series achieve:
- Reliable thermal control through advanced fuel cell cooling systems
- Precise oxygen delivery via optimized fuel cell air blowers
- Robust operation in real-world environments
This engineering focus enables users across electric mobility platforms — from drones and forklifts to hydrogen fuel cell cars — to experience efficient, safe, and long-lasting hydrogen power. Well-designed air supply and thermal management systems are key to ensuring that hydrogen fuel cells operate reliably, efficiently, and safely — demonstrating the real-world benefits and advantages of hydrogen fuel cells.