Case Study - For a clean future

Precise temperature monitoring in fuel cells

Hydrogen is a key element for the climate-neutral future. JUMO VIBROtemp temperature sensors are used to monitor the temperature in fuel cells. With over 20 years’ experience, Proton Motor Fuel Cell GmbH – an international company based in Puchheim, near Munich – is a recognized expert in cleantech-based energy solutions. With a current workforce of just under 100, the company produces environmentally friendly hydrogen fuel cells and fuel cell hybrid systems for automotive, maritime, and stationary plants as well as for rail services.


Fuel cells can best be compared to the way batteries work. Energy is produced in a chemical reaction between the anode and the cathode. The substances that react together in the fuel cell are hydrogen and oxygen. PEM (polymer electrolyte membrane) technology uses gaseous hydrogen (H2) as fuel and converts it with oxygen (O2) from the air to pure water. Electricity and heat are produced by the reaction in the cell. In contrast to traditional internal combustion engines, coal-fired power plants, and nuclear power plants no poisonous, radioactive, or environmentally harmful by-products are produced or emitted. The only waste product is water. To achieve this, however, only renewable energy must be used to produce the required hydrogen. The open-circuit voltage of the electrical circuit in the fuel cell is 1.23 V. To produce higher voltages, fuel cells are positioned one behind another, like the batteries in a pocket flashlight, and then “stacked” on top of one another.

Fuel cell stack module from Proton Motor Fuel Cell GmbH

Solution approach

Three temperature probes are required for each fuel cell stack. They are fitted in the so-called media adapter plates. These plates are installed on the PEM fuel cell stacks for media distribution and monitoring. The individual subassemblies are then combined into stack modules. Two temperature probes are required to indirectly monitor the cooling section. They are responsible for acquiring the temperature of the coolant circuit (forward and reverse flow). Another JUMO sensor fulfills a safety role. It is positioned in the outlet stream of the stack module's air gap. At that location the sensor acquires the temperature of the reaction air and indicates a stopped coolant flow in the event of overheating.

Project outcome

JUMO VIBROtemp temperature probes are used in the fuel cells from the company Proton Motor Fuel Cell GmbH. These screw-in RTD temperature probes enable temperature measurements in commercial vehicles, construction machinery, agricultural machinery, motors, compressors, and in railway technology. The vibrationresistant structure achieves excellent long-term stability even in tough operating conditions. In the example application described, the temperature probes reliably monitor temperatures up to 150 °C.