Supercapacitor Basics

let's talk about super capacitors or ultra capacitors this is a special type of electrolytic capacitor that has a construction that allows them to store much more charge than a normal electrolytic capacitor this one for example has a capacity of 500 pallets the farad is the unit of capacitance for comparison this is a normal electrolytic capacitor and has a capacitance of 47 hundred microfarads a micro farad is one millionth of a farad this means that this ultracapacitor can store more than 100 thousand times the charge that this capacitor can store well one of the disadvantages of ultra capacitors is the low voltage this one is rated at 2.7 volts and we can find also ultra capacitors of around five point five volts would not much more voltage than that this normal capacitor is rated at 25 volts and we can find electrolytic capacitors of higher voltage such as this one which has a voltage of 450 volts I'm going to run this little model of the charge stored in this normal capacitor I'm going to charge it to 6 volts and when we connect the motor we can see that the charge only lasts for a couple seconds okay now I'm going to use our super capacitor which is charged at 2.5 volts the motor turns slowly because the voltage is 2.5 volts and in this case we charge this capacitor at 6 volts however we can see how the motor is still turning and in fact it will turn for about half an hour however batteries are still better at storing energy than super capacitors a double a rechargeable battery can store a total energy of around 9000 joules or super capacitor can store an energy that is given by 1/2 of the capacitance times the voltage squared and this equals an energy of 1800 joules that is the battery can store five times the energy of the super capacitor super capacitors cannot directly replace batteries for the following reason a battery maintains an approximately constant voltage during its life this rechargeable battery when fully charged has a voltage of approximately 1 point 35 volts at the end of its life the voltage has dropped to one point one volts approximately capacitors on the other side have a voltage that drops almost linearly with charge when fully charged this capacitor has the rated voltage of 2 point 7 volts however when we have consumed half of the charge the voltage drops to approximately half this value or 1.35 volts when we have 10% of the charge the voltage is approximately point 27 volts we need additional circuitry to stabilize the voltage such as a boost converter uh advantage of super capacitors is that unlike batteries they can provide a lot of current this battery for example if we measure the short-circuit current which is the maximum current can provide we can see this it is two point five amperes in the case of this super capacitor it gives much more than that in fact I cannot measure the current with this multimeter because the maximum current that this can measure is 10 amps and the capacitor can provide much more than that but let's make a little test to see how much current this capacitor can give as we can see the wire melted immediately when we shorted the capacitor this is size 20 AWG so the coolant must be at least some 20 or 30 amps in order to charge a super capacitor you have to apply a current to it used as the super capacitor can discharge very quickly and output very high currents you can also charge it quickly if you put enough current into the capacitor as we can see the capacitor is discharged we have point zero three volts and we will charge it using this power supply then can give a maximum of five amps so let's try to connect and see how quickly is charged we can see that we are charging at 4.5 amps and the voltage in the capacitor is rising the capacitor will be fuelie charged when the voltage is 2 point 7 volts and the whole charging process takes about 3 minutes but remember that we are using less than 5 amps if we have a more powerful power supply say one that has an output of 15 amps the charging process will take just one minutes by comparison charging one battery like this takes at least one hour to have a full charge super capacitors technology is in constant development in the future they will be able to store the same amount of energy as batteries or even more and with a size comparable to batteries perhaps they will be smaller imagine charging your cell phone in a couple of minutes or even less than that

Channel: Ludic Science

Views: 669,215

Rating: 4.7630844 out of 5

Keywords: science, physics, electricity, experiment, energy, battery, Supercapacitor, Battery (Invention), Technology

Id: W4bE5zD_GxI

Length: 7min 40sec (460 seconds)

Published: Fri Oct 30 2015