"Burning" is not worthy of its name The fuel cell is an electrochemical device in principle, and its structure is the same as that of ordinary cells. The whole battery is composed of positive and negative electrodes (negative electrode is fuel electrode and positive electrode is oxidant electrode) and electrolyte. The difference is that the active substance of the general battery is stored in the battery, which limits the battery capacity. The positive and negative electrodes of fuel cells themselves do not contain active substances, but are only catalytic conversion elements. When the battery is working, the fuel and oxidant are supplied externally for reaction. In principle, as long as the reactants are continuously input and the reaction products are continuously discharged, the fuel cell can continuously generate electricity. The fuel cell is not a device for storing electricity, but an energy converter that converts chemical energy into electrical energy. The fuel of the battery can be hydrogen containing fossil fuels such as hydrogen, natural gas and methanol, or hydrogen-rich fuel, or renewable energy can be converted into hydrogen fuel. In the cell, no matter what "fuel" is added, it must be converted into hydrogen and oxygen to participate in the reaction (methanol fuel can directly react with oxygen). The core technology of fuel cell is electrode and electrolyte. The requirement for the electrode is to maximize the surface area, so the fuel cell is generally large, which is more conducive to catalyzing hydrogen (methanol) and oxygen into ionic catalysts; The electrolyte requires better conductivity to facilitate the continuous reaction, and also has the ability to isolate the generated ions, so that the ions can capture the required electrons at the electrode rather than inside the electrolyte, so as to improve the efficiency of power generation.
 Attempt to break through the bottleneck of miniaturization Fuel cell is not a new technology. As early as 1839, British W. Grove put forward the principle that hydrogen and oxygen can react to generate electricity. This is the earliest hydrogen-oxygen fuel cell. Now it has been widely used in large equipment such as emergency power supply and automobiles. However, the integration of fuel cells into mobile terminals such as laptops and mobile phones has been very slow for a long time. The root cause is the mention of its huge size. Mobile power supply without poor power In 2013, how did Lilliputian and Roma solve the bottleneck of fuel cell miniaturization with the new products launched this year? First of all, Lilliputian Nectar mobile power supply adopts a different general method: the power generation unit of this mobile power supply uses SOFC (solid oxide). After inserting the cylindrical fuel box containing butane fuel into the mobile power supply, a miniature solid oxide fuel cell is formed. The power generation capacity of each cylindrical fuel cell is 55Wh, and the high energy conversion efficiency of the miniature solid oxide fuel cell is used to obtain a practical mass production battery. The most important thing is that in terms of the core technology of the battery cell, the micro-electro-mechanical system (MEMS) chip named "Generator Chip" is used to improve the conversion efficiency, thus realizing miniaturization. This mobile power supply has been licensed from the International Civil Aviation Organization (ICAO) and the United States Department of Transportation and can be carried on aircraft. This mobile power supply will be officially launched in the summer of 2013, with a price of 299.99 dollars (about 1870 yuan). The price of each box of methane fuel is 9.99 dollars (about 62 yuan). It can charge smart phones for 10-14 times, which is equivalent to 4.5 yuan for each charge. This price is still a little expensive.
 Lilliputian Nectar移动电源，旁边立着的就是燃料盒
Thin film for adding water to generate electricity Of course, fuel cells do not necessarily need to be fueled, and water can also generate electricity. However, compared with other fuels, the technical difficulty of fuel cells with water is how to find a material to store hydrogen. External compressed gas cylinders or hydrogen absorbing materials are the conventional ideas in high-power applications such as electric vehicles. However, in the face of mobile terminal applications, direct use of hydrogen will cause problems such as large volume or complex implementation. Therefore, in portable fuel cells, the method of adding water to produce hydrogen through chemical reaction is widely used. It is precisely this method that is used in the fuel cell products of Japan's Roma Company. Calcium hydride is a gray white crystal, which can react violently with water to produce hydrogen and calcium hydroxide. The fuel source of Roma fuel cell is calcium hydride+water: the calcium hydride is solidified into a very small film. When water is injected, the water reacts with the calcium hydride sheet to generate hydrogen, and then generates hydrogen ions in the electrolyte. The ion movement generates electricity. The final product is water, which will not produce carbon dioxide and other VOC (volatile organic compounds) and other harmful substances. As the product of fuel cell operation is also water, the product only needs to add a small amount of water to initiate the reaction. A piece with a volume of 38 mm × 38mm × The Rom fuel cell with the size of 2mm can generate 4.5L of hydrogen and 5 Wh of electricity by adding water. This hydrogen fuel cell is compact and can work at normal temperature. It can not only be used for charging smart phones, but also be used as a battery for tablet computers, PCs and other devices. In terms of environmental protection, due to the use of safe substances such as water and calcium-based fuel, it will not emit carbon dioxide and harmful gases at all, and can also be treated as general waste when discarded. Compared with previous batteries, it is an extremely environmentally friendly battery. In April 2013, this fuel cell has officially started mass production. Rom's goal is to promote the use of fuel cells on smart phones within this year. Cost problem to be solved The cost of fuel cell is still high, and the main culprit is the platinum catalyst in its electrode. Platinum is a kind of rare metal, which is still used to accelerate the chemical reaction in hydrogen fuel cells. To reduce the cost of fuel cells, a simple alternative is to replace the platinum in the electrode. At present, there are iron-based catalysts, platinum-palladium mixtures and porous electrodes with polymer coating. However, all these platinum substitution methods have defects, that is, their current density is low or their performance will decline after hundreds of hours of use. In addition, since the fuel used in fuel cells is basically flammable and explosive, although there will be no explosion inside the cells, these fuels are not allowed to be carried for aviation safety. Including how to package and supply fuel to fuel cells, safety issues in fuel transportation and storage, and the urgent need to establish standards for transportation, storage, safety and testing. However, in the future, when the fuel cell is officially launched, remember to purchase the products certified by the International Electrotechnical Commission (IEC), and know whether it can be carried on the aircraft, so as to achieve environmental protection and safety assurance. |
