The micro SOFC cube has an integrated structure that has a volume of just 1 cm3, contains tubular cells with diameters of 0.8–2 mm and achieves a power density above 2 W/cm3 at 550°C.
The fuel cell technology – which represents a major step towards realizing high-power, small-size SOFC systems – was developed by researchers working at the Functional Assembly Technology Group and the Advanced Manufacturing Research Institute of the National Institute of Advanced Industrial Science and Technology (AIST), in collaboration with NGK Spark Plug Co Ltd.
SOFCs have the highest energy conversion efficiency among all fuel cells, and offer high reliability because they are made solely from solid materials. In addition, they can directly use hydrocarbon fuel.
Previously, however, SOFCs required an operating temperature of 800–900°C, which meant that their application was limited to large-scale stationary power supplies. There have been strong demands for the development of SOFCs capable of operating at lower temperatures to enable them to be used in small-size portable power supplies.
To meet the demand for extremely compact fuel cells, the collaboration between AIST and NGK has successfully developed the micro fuel cell module by optimizing the module design and ceramic electrode microstructure. As a result, the module requires a negligible amount of power to feed air into the porous solid structure – enabling the air to be supplied by natural diffusion, according to a report on AZoNano.com in Australia.
The developers say that it will be possible to create a fuel cell system with significantly improved efficiency and reduced size by using the newly developed module. In future, this technology could potentially find applications in power supplies for portable electronic devices.