How super-capacitors and batteries can work together

Everyone has heard of lithium ion batteries. These batteries are in our cellphones, laptops, cameras, watches, and other gadgets. The first commercial lithium ion batteries were produced by sony. Although they have large energy densities, they take a lot of time to recharge. On average a laptop can take 3 hours to recharge. What if we can reduce that number to a matter of seconds.

That’s where supercapacitors come in. The first supercapacitor with low internal resistance was developed in 1982 for military applications through the Pinnacle Research Institute (PRI), and was marketed under the brand name “PRI Ultracapacitor”. Then they thought “what if this can be used in fast charging applications”. Supercapacitors have a very high charge and discharge rate. It can charge and discharge within a matter of seconds, and unlike lithium ion batteries, they virtually have unlimited recharge cycles.

Let’s say we have 2 containers that store water. One is big but it has a small hole for water to come out. The other one is small, but it has a giant hole for water to come out. The first container represents lithium ion batteries, because they have big capacities, but they charge and discharge slowly. The second container represents Supercapacitors, because they have small capacities, but they charge and discharge rapidly.

Super-capacitors have energy densities of 10,000 Watts per kilogram and they can operate in temperatures of negative 40 degrees. Lithium ion batteries have an energy density of 2000 Watts per Kilogram, and can only work in temperatures only as high as 40 degrees.

Super-capacitors cost $2400 per kWh and Lithium ion batteries cost $500 per kWh, but in the long term, super-capacitors are cheaper.

Let me explain how super-capacitors work. Super-capacitors use Electrostatics instead of chemistry. Inside a capacitor there are 2 electrodes which are metal coated by a powdery activated charcoal. They use charcoal because it is pours and it has a low density which makes it an ideal material. Both the plates are soaked in an electrolyte, and they are separated by a very thin carbon insulator. The porous electrodes are like a sponge which collects electrons. Each electrode attracts the opposite charge, and this happens at a very fast rate. Super Capacitors usually have a nominal voltage of 2.3 volts.

Many might ask what is the difference between a regular capacitor and a super-capacitor. A regular capacitor stores electrical energy directly by an electrostatic field created between the two plates. Due to this, they can’t hold as much energy as super-capacitors.

Some people on the internet have said that Super-capacitors are the “next batteries”,but they are wrong. If we want to increase the capacity of the super-capacitor, we need to expand the separator, and by doing this the time it takes for the electrons to to cross the separator increases, thus increasing the charge and discharge time. Scientists are trying to find alternative materials to increase energy density of super-capacitors but not decrease charge and discharge times. Because of this, capacitors can only work with batteries, but they can not replace them.

Recently Tesla has bought Maxwell Technologies. They are one of the best manufacturers of super-capacitors in the world. Some people might wonder about the application of super-capacitors in electric vehicles.

Together batteries and super-capacitors can help in fast charging EV’s. An average tesla takes 12 hours to charge fully, but with super-capacitors they can charge fully in 30 minutes. They can also regulate the power they supply for better circulation. Super-capacitors can also help in acceleration of a car. Due to their fast discharge capability, we will be able to accelerate faster. In many gas vehicles, and hybrid vehicles, there is an important use of super-capacitors. For example the Mazda 3 and 6 have a system called the iloop. They use super-capacitors to store energy that is being lost in braking. When a vehicle brakes, the energy is converted into kinetic energy which gets stored in the super-capacitor in the form of electricity. This gives it a bit more range.

Super-capacitors are definitely the future, but they can’t immediately replace lithium-ion batteries. If You want to learn more, just visit my Youtube link https://www.youtube.com/watch?v=nzLVVX7qsmk&t=169s and consider subscribing.