A fuel cell is a so-called galvanic cell, which transforms the chemical reaction energy of a (continuously) supplied fuel and an oxidizing agent into electrical energy.

The word fuel cell is mainly used for the hydrogen oxygen fuel cell, as this has been researched very intensively and is well-known.

However, hydrogen only occurs in bound form in nature and must therefore be generated. High energy losses occur during this process.

Fuel cells are already used as energy converters for submarine drives and in space flight.

A fuel cell consists of electrodes, which are separated from one another by a diaphragm or electrolyte  (ionic conductor).

The energy is produced by a reaction of oxygen with fuel. This can be hydrogen, but it can also include organic compounds such as methane, methanol, ethane, ethanol, propane, butane and naphtha.

The two reaction partners are supplied continuously. The supplied voltage is theoretically 1.23 V for the hydrogen oxygen cell at a temperature of 25 °C. However, voltages of just 0.5-1 V are achieved in practice.

Due to the infrastructure already available, the fuel cells are often not operated directly with hydrogen, but rather with natural gas or liquid gas (e.g. ethanol).

The natural gas or liquid gas must first be converted (into hydrogen or into a hydrogen-carbon monoxide-methane mixture), before introduction into the fuel cell. This takes place in a so-called reformer.

Hydrogen-containing gases or liquids are converted in the reformer at high temperature via a catalyst into a hydrogen-rich gas, so-called reformate. CO2 is also produced during this process.

Thomas uses reciprocating pumps and diaphragm pumps (or micro metering pumps), which are driven electromagnetically, for metering and conveying fuels for fuel cells and reformers.

Thomas already supplies solenoid-operated diesel metering pumps and petrol metering pumps in the automotive sector for engine-independent heating and exhaust emission after-treatment. These are often also known as HC dosers.

Other electromagnetically driven metering pumps or delivery pumps (solenoid pumps) in the field of exhaust emission after-treatment meter AdBlue, an aqueous urea solution.

These products are designed for the entire service life of the system.