Super capacitor (Supercapa super capacitor CitoRS), also known as electrochemical capacitor (Electrochemical Capacitors), is a new type of reservoir development, the last century eighty's seven up to device. It is the power supply has a special performance, a cross between conventional capacitors and batteries, mainly rely on electric double layer and redox pseudo capacitive charge electric energy storage, which is different from the traditional chemical power source. The outstanding advantages of the super capacitor is the high power density, charge and discharge time is short, long cycle life, wide operating temperature range.
Characteristic
(1) fast charging, charging 10 seconds to 10 minutes can reach more than 95% of its rated capacity;
(2) a long cycle life, depth charge discharge cycle use frequency can reach 1~50 million times, there is no "memory effect";
(3) large current discharge ability, high energy conversion efficiency, loss of small, high current energy cycle efficiency higher than 90%;
(4) the power density is high, up to 300W/KG~5000W/KG, equivalent to 5~10 times the battery;
(5) composition, product raw material production, use, storage and dismantling process are no pollution, is the ideal green power;
(6) the charge and discharge circuit is simple, no need of charging the battery as the charging circuit, high safety factor, long term use of maintenance free;
(7) the ultra low temperature characteristics of a good, wide temperature range of -40 to +70 DEG c;
(8) the detection is convenient, the remaining power can be read directly;
(9) the capacity range of the usual 0.1F--3000F.
Fala (farad), referred to as the "law", the symbol F
1 Fala is a capacitor to store the 1 Coulomb potential difference, between the two electrode plates is 1 volts 1F=1C/1V
1 coulomb is 1A current at 1s transport power, that is 1C=1A S.
1 Coulomb =1 ampere - seconds
1 Fala =1, S / volt ampere
Analogy
Battery (battery) power =14*3600*12=604800 Fala put 12 V 14 ah (F), (Note: 12 V 14 ah battery is composed of 6 blocks to the series 2v14 ah, if changed 6 fast parallel, equal to 2v84 ah, 1V is converted to 168 ah)
The earth capacitance value is only about 1-2F
Super capacitor and battery has the following characteristics comparison:
A. super low equivalent series resistance (LOW ESR), power density (Power Density) is a lithium ion battery dozens of times, suitable for high current discharge, (a 4.7F capacitor can release the instantaneous current more than 18A).
B. long life, charge and discharge is more than 500000 times, 500 times of Li-Ion battery, is 1000 times of Ni-MH and Ni-Cd cell, if the super capacitor charging and discharging 20 times a day, continuous use of up to 68 years.
C. high current charging, charge and discharge time is short, the charging circuit simple, no memory effect.
D. maintenance free, can seal.
E. wide temperature range of -40 to +70 DEG C, the battery is generally -20 to 60 DEG C.
F. super capacitor can be series parallel composition into a super capacitor module, can withstand more high capacity storage!
Supplement
The super capacitors (supercapacitor, ultracapacitor), electric double layer capacitor (Electrical Doule-Layer Capacitor) is also called golden capacitor, capacitor, Fala, through the polarization electrolyte storage. It is an electrochemical device, but in the process of the reservoir can not occur chemical reaction, the energy storage process is reversible, it is because of the super capacitor can be repeated charge discharge hundreds of thousands of times.
The super capacitor can be regarded as suspended in the electrolyte two non reactive porous electrode plate, plus electric on the plate, positive plate attract negative ions in the electrolyte, the negative plate attract the positive ions, in fact the formation of two capacitive storage layer, is separated from the positive ion in the anode plate nearby, negative ion in the anode plate nearby. (see Figure 1)
A, super capacitor differs from traditional capacitor and its "super" where?
The super capacitor is stored in a charge separated in energy, charge storage area is greater, the separated charge for more intensive, the capacitance of the greater.
The traditional area of the capacitor is the flat area of conductor, in order to obtain larger capacity, the material of conductor winding is very long, sometimes with a special organizational structure to increase its surface area. Traditional capacitor insulating materials for the bipolar plate is the separation of it, generally for the plastic film, paper and so on, these materials are usually required as thin as possible.
The super capacitor is the area of the porous carbon materials based on porous junction, the material enough to allow its area reaches 2000m2/g, by some measures can achieve greater surface area. The super capacitor charge separation distance is determined by the size of electrolyte ions are attracted to the charged electrode. The distance (<10) and traditional capacitor film material can realize the distance smaller.
The surface area of the charge separation distance of the huge, plus a very small so that the super capacitor has surprised people's Congress electrostatic capacity than traditional capacitor, which is the "super".
Two, the super capacitor has what advantages and disadvantages?
1, the advantages of
We reached the capacitance Fala level in a very small volume;
The charging circuit and discharging circuit without special control
We compared and battery overcharge, put all the life not a negative effect;
Result from the environmental point of view, it is a kind of green energy;
The super capacitor can be welded, so there is no problem as the battery contact not firm;
2, disadvantages
* if improper use can cause electrolyte leakage;
Compared - and aluminum electrolytic capacitor, its internal resistance is larger, and therefore can not be used for AC circuit;
Three, the super capacitor has what use?
Low impedance - super capacitors are essential for many of today's high power applications. For a quick charge and discharge, the super capacitor small ESR means more power output.
*The instantaneous pulse power applications, the short time power important memory, memory system support.
Four, application examples
1, application of fast charge, a few seconds to a few minutes to charge, discharge. For example, electric tools, electric toys;
2, in the UPS system, the super capacitor provides instantaneous power output, as a supplement to the standby power engine or other uninterrupted system of;
3, applied to the energy is sufficient, the power of energy, such as solar energy;
4, when the power bus from a power source is switched to another power source support;
5, small current, long time continuous discharge, such as computer memory back-up power;
Five, I can more quickly to the super capacitor discharge?
The super capacitor can be charged and discharged rapidly, the peak current limit only by its internal resistance is not lethal, even short circuit.
It actually depends on the capacitor body size, for matching load, small body can be placed 10A, macromonomer can hold 1000A.
The restrictive conditions of another discharge rate is hot, repeated at a rate of violent will make the capacitor discharge temperature increases, eventually leading to circuit breaker.
Six, how do I discharge control of super capacitor?
The resistance of super capacitor hinder its rapid discharge, super capacitor time constant in 1~2s, completely to the resistive capacitive discharge circuit requires about 5 t, that is to say if the short circuit discharge is about 5~10s. (due to the special structure of electrode they actually have to spend several hours to the residual charge completely put clean)
Seven, the super capacitor battery than the better?
The super capacitor is different from the battery, in some applications, it may be better than the battery. Sometimes unifies both, high energy storage power characteristics and battery capacitor combination, a better way is to.
The super capacitor can be charged to any potential at its rated voltage range, and can be completely released. While the battery is affected by its chemical reaction limited work in the voltage range is narrow, if overdischarge may cause permanent damage.
The super capacitor charge state (SOC) to form a simple function and voltage, and the battery state of charge includes conversion complex.
The super capacitor and its equivalent size compared to traditional capacitors can store more energy, super capacitor battery and its size can be compared to store more energy. In the application of some power determines the energy storage device size, the super capacitor is a better way.
The super capacitor can be repeatedly transmitted pulse of energy without any adverse effects on the contrary, if the battery repeated transmission of high power pulsed the reduced life expectancy.
The super capacitor can be fast charging and battery quick charging will damage.
The super capacitor can be repeated cycle of hundreds of thousands of times, and battery life only hundreds of cycles.
Eight, how to select the super capacitor I needed?
The first, power requirements, discharge time and the system voltage changes play a decisive role.
The output voltage of the super capacitor drop is composed of two parts, one part is the release of energy super capacitor; the other part is caused by the internal resistance of super capacitor. The two part who accounted for mainly depends on the time, the pulse is very fast, the resistance part accounts for the main, on the contrary in the long time discharge, the capacitive portion occupies the main.
The following basic parameters determine your choice of capacitor size
1, the maximum working voltage;
2, the work of the cut-off voltage;
3, average discharge current;
4, the discharge time long
The market situation
The super capacitor products although come out soon, but because of its special advantages, has been applied in many fields, it can be considered a very broad prospect. Stable operation of the 2010 Shanghai World Expo in the 36 car of super capacitor bus is attracting many visitors eye. The super capacitor car once the popularization, the market will be large beyond imagination.
Engaged in domestic large capacity of super capacitor R & D manufacturers a total of more than 50, however, can be mass produced and reached the practical level of the manufacturers of less than 20. Domestic manufacturers to produce mostly liquid electric double layer capacitor, important enterprises Jinzhou kaimei power (formerly Jinzhou Fuchen, Jinzhou Jin Rong), Beijing Ji Xing Electronic, Haifeng Beijing times science and technology, Beijing United health technology, Sun Bo Iger, Shanghai Aowei 10. Jinzhou kaimei power is the largest specialized in production of super capacitor factory, the main production of button type and winding type super capacitor. Beijing Ji Xing can produce winding type and large capacitor, while Shanghai Aowei products are more concentrated in the car with the super capacitor on.
From each manufacturer's product, the core of competition among enterprises is not directly, because there is no complete duplication, competition also is confined to an area within the scope of. Is expected to have good cooperation will remain between 2010-2010 years of each enterprise, market pattern will not change much. Shanghai Aowei, kaimei, Ji Xing Electronic and several enterprises will continue to occupy the domestic market share of the vast, segment market, the competition of enterprises will be more obvious advantages. Overall, the market competition is not too fierce.
The astonishing growth in recent years Chinese consumer electronics based on performance, is expected in the next few years, China's fastener type super capacitor is expected to maintain an average growth rate of more than 30%, winding type and large super capacitor is likely to keep the average growth rate of more than 50%. By 2013, China's super capacitor the size of the overall industry is expected to reach 7900000000 yuan.
The use of attention
1, the super capacitor has a fixed polarity. Before use, should confirm the polarity. [1]2, super capacitor should be used in the nominal voltage: when the capacitor voltage exceeds the nominal voltage, will lead to electrolyte decomposition, while the capacitor will be fever, the capacity decreased, and the increase of the internal resistance, shorten life, in some cases, can lead to performance of the capacitor breakdown. High frequency circuit is applied to charge and discharge can not be 3, super capacitor, fast charge and discharge high frequency will lead to internal heat, capacitor capacity attenuation, the increase of the internal resistance, and in some cases will lead to performance capacitor breakdown. 4, the super capacitor life: the ambient temperature has an important effect on the super capacitor life. Capacitors should be kept away from heat source. 5, when the super capacitor is used to do the backup power supply voltage drop when: because the super capacitor has larger resistance characteristics, voltage drop exists in the discharge of the moment, Delta V=IR. 6, the use of gas in the environment: the super capacitor can not be in the relative humidity is higher than 85% or contain toxic gas places, these circumstances will lead to lead and capacitor casing corrosion, resulting in circuit breaker. Store 7, super capacitor:
The super capacitor can not be placed in the high temperature, high humidity environment, should be stored at the temperature of -30+50 DEG C, relative humidity less than 60% of the environment, avoid the temperature plunged sharply, as this will cause damage to the product. 8, the use of super capacitor in the double-sided circuit board: when the super capacitor for double-sided circuit board, need to pay attention to the connection does not through the capacitor can reach, the installation mode of the super capacitor, it will lead to a short circuit phenomenon. 9, when the capacitor is welded on the circuit board, not the capacitor shell into contact with the circuit board, or welding material will penetrate to the capacitor threading hole, the influence to the performance of the capacitor. 10, the installation of a super capacitor, can not be forcibly tilt or twist the capacitor, it will cause the capacitor lead wire loose, resulting in performance deterioration. 11, in the process of welding to avoid overheating: if the capacitor capacitor made in welding overheat, will reduce the service life of the capacitor, such as: if you use the thickness of the printed circuit board of 1.6mm, the welding process should be 260 degrees, time is not more than 5S. 12, cleaning after welding: in the capacitor after welding, a circuit board and a capacitor need after cleaning, because some impurities may cause the capacitor short circuit. 13, the capacitor series use: when the super capacitor is used in series, there is a voltage balancing problem of single bodies, series will lead to one or several single capacitor overvoltage is simple, thereby damaging the capacitors, the overall performance is affected, therefore in the series capacitor, support manufacturers technology. 14, other types of applications appear in the process of using super capacitor on the issue, please the relevant technical information to the manufacturer consultation or by reference to the super capacitor instructions execution
The working principle of super capacitor
According to the electrochemical capacitor energy storage mechanism is different can be divided into two categories:
1) electric double layer capacitor: is caused by charge confrontation on the electrode / solution interface by the directional arrangement of electrons or ions generated. On an electrode / solution system, can form electric double layer in the electronic conductive electrode and the ion conducting electrolyte solution interface. When the applied electric field in the two electrodes, the anion and cation in solution respectively to the positive and negative electrode migration, formation of an electrical double layer on the surface of the electrode; undo electric field, ion of positive and negative charges of opposite charge on the electrode and solution in the phase to bring the electric double layer is stable, relatively stable produce potential difference in the between the positive pole. Then on one electrode, will be within a certain distance (dispersion layer) to produce specific ion charge and charge the same amount on the electrode, the electrically neutral; when the poles and the external circuit is connected, the charge transfer electrodes on the current generated in the external circuit, solution of ion migration to the solution in electrically neutral, this is the electric double layer capacitor charge discharge principle.
2) Faraday capacitance: its theoretical model is first proposed by Conway, is on the electrode surface and near surface or bulk phase two or quasi two dimensional space, electric active material of underpotential deposition, chemically highly reversible adsorption desorption and oxidation reduction reaction, produce and electrode potential is related to the charging capacitor. For the Faraday pseudocapacitance, process the stored charge includes not only the double electric layer on the storage, but also including the oxidation electrolyte ion and the electrode active material occurrence of reduction reaction. When the ions in the electrolyte (such as H+, OH-, K+ or Li+) under the influence of the electric field by a solution diffusion to the electrode / solution interface, will enter into the active electrode surface oxide bulk phase oxidation reduction reaction through the interface, so that a large number of the charge is stored in the electrode. Discharge, these entry in the oxide ion will reverse reaction and back into the electrolyte through the above redox, at the same time the stored charge through the external circuit and released, this is Faraday quasi charge discharge mechanism of capacitor.
Series connection
In the short term, the super capacitor is very low specific energy so that it may not be used as electric vehicle energy system, but the use of super capacitor as auxiliary energy source has obvious advantages. Using the optimum combination on electric vehicles for battery ultracapacitor hybrid energy system, specific energy and power requirements of the separate battery. Electric vehicle can concentrate on the problem of energy comparison and cycle life considerations, and not too much about the specific power problem. Super capacitor has a load balancing effect, the battery discharge current to reduce the use of battery energy availability, service life is improved significantly; compared with the battery, super capacitor can absorb the kinetic energy recycling electric vehicle brake quickly and efficiently generate.
Super capacitor early and balanced and energy recovery function makes the vehicle mileage is greatly improved. But the system to the battery, super capacitor, motor and power inverter, do comprehensive control and optimization, design and application of power converter and its controller fully consider the matching between the motor and super capacitor.
2, the super capacitor application technology
Output cell and average vehicle driving power demand should be fairly, and super capacitor should be higher than the average power requirement Book Power and can absorb the regenerative energy. The actual driving power demand when the electric vehicle is higher than the drunk power super capacitor, the excess part provided by battery. The super capacitor is composed of regenerative energy charge for it, if there is no sufficient electricity, the remaining part is composed of a main battery electric vehicles when running in low power supplement. When the super capacitor is full of poetry, the regenerative braking energy based battery charging, the two quadrant DC-DC converter control power allocation between the main battery and super capacitor, and restrictions on the vehicle when running on low power super capacitor charging rate of the main battery. If there is no DC-DC converter, the main battery and super capacitor will have the same voltage, resulting in the super capacitor as the rapid change in the battery voltage.
3, the research progress of super capacitor
According to the Department of energy with super capacitance USA proposed target for electric vehicles, up to 5 W h/kg and 500 W h/kg respectively of specific energy and specific power should be the best, were more than 15 W h/kg and 1600 W h/kg. At present, still did not meet the performance index of the super capacitor, but some companies have begun to actively research and development of electric vehicles with super capacitance.
Maxwell science and technology company claims, they produce power memory PC7223 super capacitor has a capacitance of the highest current (2 700F@2.3V), and has already been put into mass production, the capacitor specific energy and power were 2.48 W/kg and 732 W h/kg. The super capacitor using 287 PC7223 capacitance series obtained 56@95F can store energy of 150 KJ, at the same time can provide 1.12 W h/kg specific energy and specific power of w/kg 330. Panasonic also successfully a series capacitor.
