The fuel cell is not strictly a battery, but is a medium for electrochemical reaction, a power generation device. Since the active material involved in the electrode reaction cannot be stored inside the battery but is supplied from outside the battery, the power is continuously output as long as the fuel is continuously input.
Methane fuel cell
The main fuel of a fuel cell is usually hydrogen, and hydrogen and oxygen are oxidized by an electrochemical reaction to output electrical energy, pure water and heat, as shown in Fig. 1.
It can be seen from the figure that since the conversion of xue can be directly converted into electric energy, there is no need to undergo multiple conversions, and there is no limitation of the Carnot cycle, so the energy loss converted into mechanical energy is saved, so that it is more than 30% more than the internal combustion engine. Energy conversion efficiency, the current efficiency can reach 70%, plus heat recovery, up to 85%, eager to become the most economical energy source.
The basic element of the fuel cell is that the two electrodes sandwich a permeable electrolyte. The two electrodes are usually added with a catalyst such as carbon powder or platinum as a catalyst to accelerate the decomposition of hydrogen and oxygen molecules into electrons and ions, and the electrolyte acts as a channel for ions. The higher the transmission efficiency, the higher the current density; while the electrolyte has a poor transmission effect on electrons, the electrons are transmitted by an external circuit, as shown in Fig. 2.
Fuel cell advantages and disadvantages
1. Low pollution: Hydrogen and oxygen are used as fuels. The products are only water and heat. If hydrocarbons are used to form water, carbon dioxide and heat, there is no pollutant.
2. High efficiency: The chemical energy in the fuel is directly converted into electrical energy, so it is not limited by the card cycle. 3. No noise: When the battery body is generating electricity, there is no need to cooperate with other parts, so there is no noise problem. 4. Versatility: The range of power supplied is quite wide, ranging from calculators to power plants.
3.No need to charge: The battery body does not contain fuel, and it can continuously generate electricity by continuously supplying fuel.
1. The fuel source is not universal: hydrogen storage can be said to be difficult and dangerous, while methanol, ethanol, or natural gas
Lack of supply system, can not be easily supplied to users.
2. There is no standardized fuel: there are natural gas, methane, methanol and hydrogen as fuels on the market today.
Batteries, while offering consumers a wide variety of options, are difficult to profit because there is no single and standardized fuel, and the replacement of fuel types has the potential to retrofit existing supply systems at an additional cost.
3. The volume is too large: the current fuel cell volume is too large to carry and is inconvenient.
4. Cost is too high: At present, fuel cells use materials that can increase the efficiency of power generation, but the cost is relatively high. However, through the improvement of manufacturing technology and mass production, the cost has dropped a lot.
Methane fuel cell development prospects
The fuel cell is a dynamic mechanism in which a battery body and a fuel tank are combined. Fuel selectivity is very high, including pure hydrogen (H2), methanol (CH3OH), ethanol (CH3CH2OH), natural gas, and even the most widely used gasoline, can be used as fuel for fuel cells. This is currently not possible with all other sources of power. The use of fuel cells as the driving force of automobiles has been recognized as an inevitable trend in the 21st century.
Fuel cells generate electricity by reacting with a flammable fuel and oxygen; usually flammable fuels such as gas, gasoline, methane (CH4), ethanol (alcohol), hydrogen, etc., are burned by heating water to boil water. And let water vapor drive the turbine to generate electricity. In this way, most of the energy is usually converted to useless heat.
The conversion efficiency is usually only about 30%, and the fuel cell is a special catalyst that reacts the fuel with oxygen to produce carbon dioxide (CO2) and water (H2O). It does not need to push the power generator such as a turbine, and does not need to heat the water. Until the water vapor is returned to the water by heat dissipation, the energy conversion efficiency is as high as 70%, which is about 40% higher than the general power generation method; the advantage is not only that, the carbon dioxide emission is much lower than the general method, and the water is no. The harmful product is a low-pollution energy source.