Fuel Cells are electrochemical devices that directly convert the chemical energy to the electricity. Due to the high energy density of chemical fuels, fuel cells are often proposed as a possible solution for satisfying the energy requirement of portable devices. In order to clarify the potential of Fuel cell technology, we can compare the energy density of Propane, 23 Wh/cm3, to Li-ion battery, 0.6 Wh/cm3. The large difference suggests that a system with even a moderate efficiency can beat the currently used technology.
Fuel Cells consist of an electrolyte, an ion conducting layer, that is sandwiched between two electrodes, thus forming Positive Electrode-Electrolyte-Negative Electrode (PEN) structure. Depending on the material in use Fuel Cells are classified into different types such as Solid Oxide Fuel Cell (SOFC), Direct Methanol Fuel Cell (DMFC), Proton Exchange Membrane Fuel Cell (PEM) and etc.
The performance of Fuel Cells is highly dependent on using fuel. Hydrocarbon fuels and in principle propane gives the highest energy density, however, it is limited to high-temperature fuel cells such as SOFC, except if a gas reformer for syngas production is applied.
The combination of Fuel Cells with fuel containers puts miniaturized SOFC with propane fuel on top of all other available power sources including miniaturized PEM and DMFCs. Miniaturized SOFC is the core technology of INERGIO systems which gives superior characteristics to our devices in comparison to existing technologies according to the energy density per volume and weight.
Solid Oxide Fuel Cell (SOFC) Operating Principle
The fuel is continuously fed to the anode side and the oxidant (oxygen from the air) is supplied to the cathode side. There, the electrons dissociate and reduce absorbed oxygen and consequently forms oxygen ions. The ions diffuse through the electrolyte and oxidize the fuel at the anode side, where the oxygen vacancies are formed in consequence. The product of the reaction is thus electrons plus water steam and carbon dioxide.