Fuel Cell Stacks
A fuel cell stack is the heart of a hydrogen-based drive or energy system. Here you can find a concise and easy-to-understand explanation of how this technology works.
What is a fuel cell stack?
A single fuel cell element generates only a low electrical voltage (less than 1 volt). To power high-performance applications such as electric cars, buses, or stationary industrial equipment, many of these individual cells are stacked on top of each other and connected in series.
This is called a stack. The more cells are combined, the higher the overall power output of the system.
The design of a single cell
Each cell in the stack consists of three main components:
- Anode (negative pole): This is where hydrogen (𝐻2) is supplied.
- Cathode (positive pole): This is where oxygen (𝑂2) from the ambient air flows in.
- Electrolyte membrane: This lies like a wafer-thin separating layer between the anode and cathode and only allows protons to pass through.
How electricity generation works
An electrochemical reaction known as cold combustion takes place in the stack:
- The hydrogen is split into protons and electrons at the anode.
- The protons migrate through the membrane to the cathode side.
- The electrons have to take a detour via an external circuit – this flowing current drives the electric motor or the system.
- At the cathode, protons, electrons, and oxygen combine to form pure water.
The advantages at a glance
- Emission-free: The only waste products are water vapor and heat.
- High efficiency: Fuel cells convert chemical energy directly into electricity, making them more efficient than combustion engines.
- Scalability: The number of cells in the stack allows the output to be precisely adjusted to demand – from single-family homes to heavy trucks.