Two issues in improving the environmental performance of SOFCs
I mentioned at the outset that SOFCs have a high operating efficiency. We have been working to further improve environmental performance. I’d like to explain two main issues. (While pointing to the slide) The first issue is to reuse the fuel at the exit of a cell stack. This schematic diagram shows the process of power generation. A fuel is charged from the top, and electricity is generated in the white cylindrical cell stack. Ideally, when the hydrogen fuel input is 100, all of it should be used up in the cell stack to generate power, and there should be no hydrogen fuel remaining at the exit of the cell stack. However, the cell stack deteriorates if all the hydrogen is used, so it is controlled so as not to use up the fuel.
The ejector shown at the top of this diagram plays a key role. Derived from DENSO’s proprietary technology, it is a high-quality and highly reliable component that is also used in car air conditioners. The ejector recycles (recirculates) the unused fuel from the exit to minimize wasted hydrogen, thereby improving the power generation efficiency.
The second issue is to control the temperature to maximize the efficiency. SOFCs operate most efficiently in a certain temperature range. It is also crucial to attain a uniform and appropriate temperature.
To fully utilize the heat that is produced during power generation, we harness our thermal management technology to improve the durability. The whole company has worked to apply the technologies refined in the automotive field to other products.