 Equalizing pressure. Otherwise, when the voltage is added to a series of capacitors, the capacitance of each capacitor can not be all the same, and the voltage of each capacitor is not the same, which will cause some capacitor voltage to exceed the maximum voltage and damage. Supercapacitor battery is also called gold capacitor or Farad capacitor. It stores energy through polarized electrolyte, which is a kind of double electric capacitor. The process is reversible because there is no chemical reaction, and because supercapacitors can be charged and discharged hundreds of thousands of times. Supercapacitors generally use activated carbon electrode materials, which have the characteristics of large adsorption area and large electrostatic storage, and are widely used in new energy vehicles. Supercapacitor battery, also called electric double-layer capacitor, is a new type of energy storage device. It has the characteristics of short charging time, long service life, good temperature performance, energy saving, and environmental protection. Supercapacitors are widely used. Used as power balance power supply for lifting device, can provide super current power; Used as a vehicle start power supply, start efficiency and reliability are higher than the traditional battery, can be all or part of the replacement of the traditional battery; The traction energy used for vehicles can be used to produce electric vehicles, replace the traditional internal combustion engine, and transform the existing trolleybus. Used in the military can ensure the smooth start of tanks, armored vehicles and other tanks (especially in the cold winter), as the pulse energy of laser weapons. In addition, it can also be used for energy storage of other mechanical and electrical equipment Supercapacitors because of the increasing shortage of oil resources and the increasingly serious environmental pollution caused by the exhaust emissions of oil-burning internal combustion engines (especially in large and medium cities), people are studying new energy devices to replace internal combustion engines. The research and development of hybrid power, fuel cell and chemical battery products and applications has achieved certain results. However, due to their inherent fatal weaknesses such as short service life, poor temperature characteristics, environmental pollution of chemical batteries, complex system and high cost, there has been no good solution. Supercapacitors, with their excellent characteristics, can partially or completely replace the traditional chemical batteries for traction power and starting energy of vehicles, and have a wider range of uses than the traditional chemical batteries. Because of this, countries all over the world (especially western developed countries) spare no effort to research and develop supercapacitors. Among them, the United States, Japan, Russia and other countries not only take the lead in R&D and production, but also set up special national management institutions (such as USABC in the United States, SUN in Japan, REVA in Russia, etc.), formulate national development plans, which are actively promoted by the state with huge investment and manpower. In terms of the super capacitor technology, Russia walk in front of the world at present, its products have been commercially production and application, and by the 17th annual international electric vehicles (EVS - 17) rated as the most advanced products, Japan, Germany, France, Britain, Australia and other countries are also catch-up, at present the application of super capacitor has been quite widely. Promoting the use of supercapacitors in China can reduce oil consumption and reduce dependence on oil imports, which is beneficial to national oil security. Effectively solve urban exhaust pollution and lead-acid battery pollution problems; It is beneficial to solve the problem of low temperature start of the chariot. At present, there are more than 10 domestic enterprises in the research and development of supercapacitors Supercapacitor is a new kind of capacitor based on the interface double layer theory put forward by German physicist Helmholtz. It is well known that the metal electrode inserted in electrolyte solution will have an excess charge with opposite sign on both sides of the liquid surface, resulting in potential difference between phases. Therefore, if two electrodes are inserted into the electrolyte at the same time, and a voltage less than the decomposition voltage of the electrolyte solution is applied between them, then the positive and negative ions in the electrolyte will rapidly move toward the poles under the action of the electric field, and form a tight charge layer on the surface of the two upper electrodes, namely the double electric layer. It formed by the electric double layer and traditional capacitor of the dielectric in electric field under the action of the polarization charge similar, resulting in a capacitance effect, closely similar to electric double layer plate condenser, however, due to the tight than ordinary capacitor charge layer between the charge layer spacing distance is much smaller, thus has greater capacity than the general capacitor. Compared with aluminum electrolytic capacitors, double layer capacitors have larger internal resistance, so they can be directly charged without load resistance. If overvoltage charging occurs, double layer capacitors will open the circuit without damaging the device, which is different from the overvoltage breakdown of aluminum electrolytic capacitors. At the same time, compared with the rechargeable battery, the double layer capacitor can be charged for unlimited current, and the charge times can reach more than 10E6 times, so the double layer capacitor not only has the characteristics of capacitor, but also has the characteristics of battery, is a new special component between the battery and capacitor. The capacity of ultracapacitors is much larger than that of ordinary capacitors. Because of its large capacity, external performance and the same battery, it is also called "capacitor battery" or "gold battery". Supercapacitor battery also belongs to double layer capacitor, which is the largest type of double layer capacitor that has been put into mass production in the world at present. Its basic principle is the same as other kinds of double layer capacitor, which uses the double layer structure composed of activated carbon porous electrode and electrolyte to obtain large capacity. The electric energy stored in the traditional physical capacitor comes from the separation of charge on two plates, which are separated by vacuum (relative permittivity 1) or A layer of dielectric material (relative permittivity ε). The capacitance value is C=ε·A/3.6πd·10-6(μF), where A is the plate area and D is the thickness of the medium. The stored energy is :E=C(δ V)2/2, where C is the capacitance value and δ V is the voltage drop between the plates. It can be seen that in order to obtain A larger electric capacity and store more energy, it is necessary to increase the area A or reduce the thickness of the medium D. However, this expansion space is limited, leading to its small electric capacity and energy storage. Supercapacitors using activated carbon materials made of porous electrodes, at the same time, in a relatively between porous carbon electrode filling the electrolyte solution, when the applied voltage at both ends, relatively gathered electron-positron respectively, and the porous electrode and the positive and negative ions in the electrolyte solution due to electric field respectively gathered in contrast with positive and negative plates of interface, thus forming two collector layer, the equivalent of two capacitors Machine series, due to the activated carbon material with high specific surface area of 1200 m2 / g or higher (A) electrode area of the great, and the electrolyte and the interface between the porous electrode distance less than 1 nm (i.e., the minimal medium thickness d), according to the previous calculation formula can be seen that the electric double layer capacitor is bigger than the traditional physical capacitance of the capacitor value A lot, specific volume The amount can be increased by more than 100 times, so that the capacitance per unit weight can reach 100F/g, and the internal resistance of the capacitor can be kept at a very low level, carbon materials also have the advantages of low cost, mature technology and so on. So that the use of capacitors for large energy storage becomes possible, and in practical use, can be through series or parallel to improve the output voltage or current. [1] |