What is the working principle of a capacitor? What does this have to do about electric vehicles? Let's start with capacitors.
CAPACITOR BASICS
A capacitor is basically a device that stores energy on one plate and then releases it to another plate. This article will explain the operation of a parallel plate capacitor. This article is simplified to make it easier for you, so the Calculus is not included.
Imagine two metal plates placed close together. The distance between plates can vary from nanometers up to centimeters. The plates can be square, cylindrical, round, or any other shape.
You can choose to have air, vacuum, or another material between the plates. The dielectric medium is the material between the plates. The distance between plates and permittivity between plates affect the amount of charge, or Capacitance, as well as the area between them.
The plate area and permittivity also increase the capacitance. It decreases as the plates are further apart.
This equation yields: The capacitance is equal to permittivity (dielectric), x plate area, / distance between plates.
HOW DO THEY WORK?
Charge builds up on the capacitor plate near the power source or battery in the capacitor circuit when it is switched on. The plate will stop accepting any additional charge once it reaches the maximum capacitance. As long as there is power, the charge will remain on the plate. The capacitor's charge will start to release its energy onto the other plate once the power is turned off.
The stored energy will flow through the plates and continue down the circuit until the device requires power.
The capacitor will recharge itself after it has discharged. This process will continue hundreds of thousands to millions of times. This is the beauty of capacitors. There are no moving parts. They are durable.
Capacitors are excellent at storing and discharging charge on demand, but they do have some limitations. They are unable to store charge for long periods of time and have a low energy density. They are not as energy-efficient as lithium ion storage battery. Both of these limitations are being investigated.
CAPACITORS IN ELECTRIC VEHICLES
Now you are familiar with the basic principles of how a capacitor works. What does a capacitor do for electric vehicles? Braking is the main purpose of capacitors right now. Because capacitors are able to accept energy quickly and batteries take a while to charge, they can be well-suited to store energy that is normally lost during braking.
Hybrid vehicles are an example. The on-board alternator of hybrid vehicles can be used to generate power. The generator works by slowing down the car and simultaneously charging the capacitors and batteries. Regenerative braking has been reported by hybrid taxi drivers to have less brake wear. Regenerative braking is also available for pure electric vehicles such as the Nissan Leaf.
It is possible that ultracapacitors, also known as ultracaps, could eventually replace batteries. Ultracapacitors can be charged very quickly. Ultracaps are not able to store energy for very long and can't be used for long-term storage like batteries. The research is ongoing.