Solid Oxide Fuel Cell (SOFC)

Solid oxide fuel cell (SOFC) is the most efficient fuel cell, also known as ceramic fuel cell. It is a fully solid-state fuel cell that efficiently converts the chemical energy of various fuel gases (natural gas, landfill gas, coal gas, methanol, etc.) into electrical energy at medium and high temperatures.

1. Fuel cell reaction environment and composition

Generally, SOFC can achieve full load operation at temperatures above 650 degrees. At the system level, fuel supply system (pre-reformer), gas supply system (heater, compressor), control system (voltage regulator, inverter) and other components are also required to ensure the stable operation of the entire system. The working efficiency can reach 65%~80%. Due to the high working temperature, its reaction activity is extremely high. SOFC consists of a single cell composed of electrolyte (ceramic material), anode/cathode, and connector (ceramic or alloy), and a stack composed of multiple single cells. 

2. Application scenarios 

SOFC can be applied to distributed power generation, backup power supply and cogeneration, and can be used in hydrogen production, integrated energy supply stations, energy storage, chemical energy conservation, transportation applications (mainly used in commercial vehicle range extenders and ship auxiliary power), etc.

1. Multiple fuel selectivity SOFC can use natural gas, synthesis gas (mixed gas such as CO, H2), biomass gas (such as biogas), etc. as raw materials, and can also use coal-to-gas, coal-bed methane, shale gas, industrial by-product gas, etc. as raw materials, which can improve the conversion efficiency of traditional fossil energy, reduce CO2 emissions, and achieve clean and efficient use of fossil energy.

2. High electrolysis efficiency SOFC can generate electricity when running forward, and solid oxide electrolysis cell (SOEC) when running reversely. SOEC can use waste heat and renewable electricity, and high-temperature water vapor and high-temperature CO₂ can be compatible with large-scale application of SOEC technology, with an electrolysis efficiency of up to 85%~95%, which is much higher than other water electrolysis technologies.

3. Combined heat and power improves energy efficiency. The power generation scale of micro combined heat and power systems is usually 1 to 5 kW. It can directly supply electricity and heat energy converted from natural gas to individual users. When there is surplus electricity, it can sell electricity to the power grid. This decentralized combined heat and power system greatly saves primary energy consumption and improves energy efficiency. Japan and Europe are the two main regions for the development of micro combined heat and power systems. Their more famous demonstration projects are Ene-farm and Ene-field.

4. Compatible with traditional fuels SOFC can use traditional fuels, but its startup time is longer, which is suitable as an auxiliary power unit for luxury cars, leisure vehicles and heavy trucks.

5. Can be used for portable power SOFC-based micro power generation systems are also expanding into the field of portable power, mainly because SOFC has a higher specific power density [specific power density is a description of the ability of a battery to release a large amount of energy in an instant. ], and micro-tube SOFC can meet the requirements of rapid startup.