What is the voltage of a hydrogen fuel cell?
A hydrogen fuel cell’s voltage per cell is not a fixed value. The thermodynamic limit is about 1.23 volts per cell under standard conditions, while practical operation typically yields roughly 0.6 to 0.8 volts per cell when producing power, and the open-circuit voltage is generally about 1.0 to 1.2 volts.
Cell voltage fundamentals
Understanding the voltage of a single hydrogen fuel cell requires looking at both its theoretical ceiling and real-world losses. The following points summarize the core ideas.
- Thermodynamic maximum (reversible voltage): about 1.23 V per cell at standard conditions for the overall reaction H2 + 1/2 O2 → H2O.
- Open-circuit voltage (OCV): typically around 1.0–1.2 V per cell when no current is drawn.
- Voltage under load: actual operating voltage falls due to polarization losses as current increases—activation losses at the electrodes, ohmic losses from resistance, and concentration losses from reactant depletion.
- Influencing conditions: temperature, pressure, and humidity affect reaction kinetics, membrane conductivity, and water management, all of which shape the observed voltage.
- Design factors: catalyst activity, membrane thickness, gas diffusion layers, and overall water management influence how closely a cell can approach its theoretical potential.
In short, the observed voltage of a cell under operation reflects a balance between the thermodynamic potential and multiple loss mechanisms, so it sits below the theoretical ceiling and shifts with operating conditions.
Voltage ranges in practice and stacking
To translate per-cell voltage into a usable system voltage, engineers consider typical voltage ranges and how many cells are connected in a stack. This section outlines the practical numbers and how they combine.
- Theoretical maximum (reversible voltage): ≈1.23 V per cell under standard state conditions.
- Open-circuit voltage (OCV) for PEM fuel cells: typically ≈1.0–1.2 V per cell when not delivering current.
- Operating voltage under moderate load: commonly ≈0.6–0.8 V per cell.
- Voltage at high current density: can drop to ≈0.5–0.6 V per cell or lower depending on design and conditions.
- Stack voltage concept: multiply the per-cell voltage by the number of cells in the stack to obtain total system voltage; for example, a 100-cell stack at around 0.75 V per cell yields about 75 V, with higher or lower values depending on operating point.
In practice, designers choose the number of cells to reach a target system voltage while balancing efficiency, cooling, and power demands.
Summary
Hydrogen fuel cells operate below their thermodynamic ceiling of 1.23 V per cell when delivering power, typically around 0.6–0.8 V per cell at moderate loads and about 1.0–1.2 V per cell when open-circuit. The overall system voltage depends on how many cells are stacked. Loss mechanisms—activation, ohmic, and concentration losses—govern the gap between the theoretical maximum and real-world performance. Understanding these figures helps explain how fuel-cell systems are designed for cars, stations, and stationary power applications.
What voltage does a hydrogen fuel cell produce?
0.5 V to 0.8 V
A typical hydrogen fuel cell produces 0.5 V to 0.8 V per cell. To increase the voltage individual cells can be connected in series. This arrangement is called a fuel cell stack.
Is a hydrogen fuel cell AC or DC?
direct current
Power Conditioners
Power conditioning includes controlling current (amperes), voltage, frequency, and other characteristics of the electrical current to meet the needs of the application. Fuel cells produce electricity in the form of direct current (DC). In a DC circuit, electrons flow in only one direction.
Can I power my house with a hydrogen fuel cell?
You can absolutely use fuel cells to generate power on site. The scale of fuel cells is plenty small enough they make for fine building-sized power. They aren't cheap, but in some cases that's not a particularly critical concern as they are long lasting, quiet and low/zero emission.
What is the biggest problem with using hydrogen in a fuel cell?
For all the many advantages of hydrogen fuel cells, there are still a few disadvantages and challenges to address:
- Hydrogen Extraction.
- Investment is Required.
- Cost of Raw Materials.
- Regulatory Issues.
- Overall Cost.
- Hydrogen Storage.
- Infrastructure.
- Highly Flammable.
