Polttokennojärjestelmiä

Polttokennojärjestelmiä, known in English as fuel cell systems, are electrochemical devices that convert chemical energy from a fuel into electricity through a chemical reaction with an oxidizing agent. The most common fuel used is hydrogen, and the oxidizing agent is oxygen from the air. Unlike batteries, which store energy, fuel cells produce electricity as long as fuel and oxidant are supplied. This continuous operation makes them suitable for a wide range of applications.

A basic fuel cell consists of an anode, a cathode, and an electrolyte. The fuel is introduced to the anode, where it is oxidized, releasing electrons and protons. The electrolyte allows the protons to pass through to the cathode while blocking the electrons. The electrons travel through an external circuit, creating an electric current. At the cathode, the protons, electrons, and the oxidant combine to form a byproduct, often water.

The performance of a fuel cell system depends on several factors, including the type of electrolyte, operating temperature, and the catalysts used. Different types of fuel cells exist, such as proton-exchange membrane (PEM) fuel cells, solid oxide fuel cells (SOFCs), alkaline fuel cells (AFCs), and phosphoric acid fuel cells (PAFCs), each with distinct characteristics and applications. PEM fuel cells are often used in vehicles due to their low operating temperature and high power density, while SOFCs are suitable for stationary power generation due to their efficiency at high temperatures.

Fuel cell technology is considered a promising clean energy solution as it can produce electricity with high efficiency and low or zero emissions, depending on the fuel used. When hydrogen produced from renewable sources is used, the entire system can be virtually emission-free. Applications range from powering vehicles and portable electronic devices to providing backup power and large-scale electricity generation.