Introduction to hydrogen energy and fuel cells

Fuel cells can be divided into proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells according to the electrolyte properties and fuel used

(DMFC), phosphoric acid fuel cell (PAFC), molten carbonate fuel cell (MCFC), solid oxide fuel cell (SOFC), alkaline fuel cell (AFC), etc. For example, proton exchange membrane fuel cells (PEMFC) mainly rely on proton exchange membrane transfer proton medium, alkaline fuel cells (AFC) use alkaline water-based electrolyte such as potassium hydroxide solution as proton transfer medium, etc. In addition, according to the working temperature, fuel cells can be divided into high temperature fuel cells and low temperature fuel cells, the former mainly includes solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC), The latter include proton exchange membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), alkaline fuel cells (AFC), phosphoric acid fuel cells (PAFC), etc.

Proton exchange membrane fuel cells (PEMFC) use water-based acidic polymer membranes as their electrolytes. PEMFC cells must operate under pure hydrogen gas due to their low operating temperatures (below 100 ° C) and the use of noble metal electrodes (platinum based electrodes). Compared with other fuel cells, PEMFC has the advantages of low operating temperature, fast start-up speed, high power density, non-corrosive electrolyte and long service life. Thus, it has become the mainstream technology currently applied to fuel cell vehicles, but also partially applied to portable and stationary devices. According to E4 Tech, PEMFC fuel cell shipments are expected to reach 44,100 units in 2019, accounting for 62% of the global share; The estimated installed capacity reaches 934.2MW, accounting for 83% of the global proportion.

Fuel cells use electrochemical reactions to convert chemical energy from fuel (hydrogen) at the anode and oxidant (oxygen) at the cathode into electricity to drive the entire vehicle. Specifically, the core components of fuel cells include engine system, auxiliary power supply and motor; Among them, the engine system mainly includes the engine composed of electric reactor, vehicle hydrogen storage system, cooling system and DCDC voltage converter. The reactor is the most critical component. It is the place where hydrogen and oxygen react. It is composed of multiple single cells stacked together, and the main materials include bipolar plate, membrane electrode, end plate and so on.