1 proton exchange membrane fuel structure and principle
According electrolyte fuel cell can be divided into different fuel cells to phosphoric acid, alkaline fuel cells, solid oxide fuel cells, molten carbonate fuel cells and proton exchange membrane fuel cell (PEMFC) and five. PEMFC single cell with a proton exchange membrane, the gas diffusion electrodes, bipolar plates and other accessories. B170PW01 B170PW02 B170PW03
PEMFC the basic workflow is as follows:
(1) of hydrogen gas across the bipolar plate of the guide channel to reach the anode of the battery, the hydrogen molecules in the catalyst under the dissociation of hydrogen ion formation and electron;
(2) hydrogen hydrated proton H + (xH 2O) in the form of the membrane to the cathode through the electrolyte, the accumulation of electrons in the anode side;
(3) oxygen through the bipolar plate to the cathode, oxygen molecules in oxygen under the action of the ion catalyst, the cathode and the anode, forming a potential difference;
(4) Anode and cathode connected through the external circuit, the electronics will accumulate in the anode through the external circuit to the cathode, the formation of the current, borne to act. At the same time, the reaction of water in the side of the cathode;
(5) As long as the continued provision of reactive gas, PEMFC can operate continuously to provide power to the outside. CLAA154WA01 HSD101PFW2 HT14X11
Two proton exchange membrane characteristics of fuel cells
(1) High yield. PEMFC way for the conversion of electrochemical energy, there is no combustion process, not subject to the limitation of the Carnot cycle, thermal efficiency can theoretically reach 85-90%, the actual efficiency of engine internal combustion course is about twice as much. To improve the efficiency of traditional sources of energy must be limited to a small range of load, while the PEMFC load range almost all have a very high yield.
(2) Modular. PEMFC in the modular characteristics of different power according to demand a fixed combination, a building toy “type of approach simplifies the design of a different size stack design process and manufacturing.
(3) High reliability. As the PEM fuel cell modular, simple structure, easy to maintain. Once a single cell failure can automatically take the appropriate measures to protect these will only make the system output has declined slightly, but not lead to paralysis of the complete electrical system.
(4) Fuel diversity. PEMFC power system can be pure hydrogen as fuel, you can re-gas as fuel. source of hydrogen can be produced from the electrolysis of water can also be a gasoline, diesel, dimethyl ether and other products of fossil fuel reform. Hydrogen can be stored at high pressure cylinders, liquid hydrogen, metal hydride, etc. HT14X12 HT14X19 LP089WS1
(5) Environmentally friendly. When using pure hydrogen as fuel, PEMFC is the only product of water, may be zero emissions. To restructure the gas as a fuel compared to internal combustion engines, emissions are significantly reduced. In addition, PEMFC has very low noise level, the structural components can be recycled.
3 research staus
3.1 Components Key
Electrolyte membrane, bipolar plates, catalysts and gas diffusion electrodes for proton exchange membrane fuel cell of the four key elements.
Electrolyte membrane is the core component of the PEMFC, it directly affects the performance of fuel cells and life expectancy. 1962, DuPont developed perfluorinated acid proton exchange membrane fuel in 1966, its business model as Nafion, is still widely used. However, the high cost of Nafion membrane, scientists are studying some countries fluoride or proton exchange membrane fluoride.
Playing in support PEMFC bipolar plate, the flow rate, oxidant and reducer divide and direct the flow of gas to the surface of the battery electrode, the role of graphite is widely used as materials in its guidelines on the treatment of flow rate of gas flow field, the field of basic flow form of serpentine, parallel, crossed fingers and grid-like, and so on. apple ibook g4 14-inch battery apple macbook 13 inch battery
Performance of platinum-based catalyst is the best catalyst electrode to improve the use of platinum in the form of highly dispersed nano-particles to the impregnation of the conductive and corrosion resistance of immobilized cells, the present use extensive of immobilized cells in acetylene black, specific surface area of approximately 250m2 / g, average particle size is 30 nm.
Electrode PEMFC gas diffusion consists of two layers, one layer to play a supporting role in the diffusion layer, another layer of sites for the electrochemical reaction of the catalyst layer. Diffusion layer of carbon is usually used as a carbon material such as graphite paper or carbon cloth preparation, should have a high porosity and appropriate distribution of pore size, does not cause corrosion or degradation. Preparation and thickness for different catalyst layer is divided into a thin layer of hydrophobic, hydrophilic, and thin three types. apple a1189 apple ibook g4 12-inch battery