Despite their seemingly quick rise in popularity over these past few years, electric cars have had to overcome a lot of obstacles to get to where they are today. After all, it wasn’t until fairly recently that people started to genuinely consider electric cars as viable replacements to combustion-based vehicles.
Given the many misunderstandings people have about electric cars, it comes as no surprise that people often ask why can’t electric cars charge themselves as they’re being driven.
In all fairness, it may sound like an honest inquiry and yet it betrays a misconception about how electric motors operate. That said, let’s find out more about the functional principles of electric cars and why charging ‘on the go’ may yet prove nearly impossible with today’s technology.
The Basics – How Do Electric Cars Work?
To better understand why self-charging is so difficult to engineer, we should first try to understand the basic operating parameters of all electric vehicles across the board. Although they can differ in certain ways, most electric cars work according to the same basic principles.
Electrical Energy VS Combustion
By employing electrical energy instead of combustion, electric vehicles (EVs) employ electrical energy instead of explosive combustion to turn the electric motor(s) connected to the wheels of the vehicle This means that your average EV has fewer moving parts than traditional gas-powered vehicles.
That said, the most common electric cars are still hybrids, meaning that they run mainly on fossil fuels like petrol or diesel while also equipped with an electric motor and a built-in battery bank. These cars do indeed charge themselves while the combustion engine is running, which is where the confusion probably comes from with regard to electric vehicles.
What’s interesting about electric cars is that they have, on average, about 90% fewer moving parts than cars with combustion engines. To be more precise, your standard electric car has:
- An electric engine – This electric engine or motor provides power to rotate the wheels just as a combustion engine would. With regards to the type of electricity, the motor can either be DC or AC although AC motors are far more common.
- An inverter – The inverter is tasked with converting the electric current from DC into AC. The invertor’s capacity can vary from one model to another.
- A drivetrain – Most EVs employ a single-speed transmission that powers the wheels with energy from the electric engine.
- Batteries – Pretty self-explanatory, the batteries are used to store the electricity required to run the vehicle. The higher the kW of the battery, the higher the operational range of the car.
- Charging system – This is the part that accommodates the plug we use to charge the EV. It connects directly to the battery system.
Many consumers wonder whether buying an EV is worth it on account of their presumed short operational range. This is exacerbated by the fact that EVs are also slow to recharge when they run out of juice.
On average, an electric car can go for about 200 to 250 miles on a single charge, but this may vary depending on the make and build of the car. Toward the high-end of the quality spectrum, there are electric vehicles that you can drive for up to 400 miles on a single charge.
So Why Can’t Electric Vehicles Charge Themselves?
Electric vehicles cannot charge themselves because they lack an alternator. You see, combustion vehicles incorporate a mechanism called an alternator. This is an electric generator tasked with converting mechanical energy into electricity. This electricity can then be used to charge the battery while the car is moving.
The design of an alternator allows it to use kinetic energy (energy generated through movement) and potential energy (energy generated by stress within an object) in order to produce an electric charge, a charge that goes straight to the battery or else it is lost.
As we all know, combustion cars require a battery to start up the engine, which then provides mechanical energy to the alternator, which then produces electricity to replenish the battery. In other words, it is a closed circuit that converts kinetic energy into electricity.
In an electric car, however, the energy is produced by the battery itself, with no auxiliary systems to recharge it once it’s exhausted.
In the absence of a secondary source of energy, the use of an alternator would be pointless, because the alternator would do nothing more than exhaust whatever energy was already present. This would then drain the battery even further, rather than help charge it in any meaningful way.
Efforts are made every day by car manufacturers to design a system that would use the car’s movement as a catalyst for charging the battery on the go. So far, such technologies are still in the development/prototype stage.
Self-Charging Systems – Can It Be Done?
In spite of all the obvious limitations, a self-charging system may very well be possible given the pace at which EV technologies are currently evolving. For that to happen, the system would have to emulate an electrical generator of sorts, which may prove quite difficult to engineer.
For the time being, the possibilities of a self-charging system are limited, but not absent. The only viable solutions could come from:
Regenerative braking is a system employed by electric cars that uses a secondary method to harness energy that doesn’t rely on the battery but rather on the kinetic energy of the car when it’s in motion.
This system uses a regenerative hydraulic braking system that provides two types of breaking – a generator mode, and a pure brake mode.
As such, when the driver uses the brake pedal, the generator mode is automatically engaged and the kinetic energy produced by the wheels spinning is then transferred through a drivetrain to a stand-alone generator that isn’t part of the EV’s motor.
This is a sure way to harness some of the car’s braking power and provide an effective kinetic energy capture method.
Another way to harness power on the move is through the use of solar panels built onto the electric car itself.
This ingenious but peculiar system could make use of solar panels on the body of the car to charge the battery without interfering with the car’s main electrical system. The solar panel system would then act as a secondary energy source for the vehicle itself.
Unlike kinetic energy capture systems that require input from the driver, the solar panel mechanism would theoretically function around the clock via solar cells.
Needless to say, the amount of solar power harnessed this way would be much smaller than kinetic-based systems that make use of the car’s mechanical energy while it moves.
Although passive charging is seen as somewhat of a pipe dream at the moment, the use of a passive charging system that would act as a secondary energy source is definitely something that engineers are looking into at the moment.
Such a system would have to use the car’s motion as a way to harness electrical energy, similar to how regenerative braking uses the car’s mechanical energy.
The idea that you could use a passive method to harness additional energy is still in the works for the time being, so we couldn’t really comment on the practical applications of such a system.
Induction charging is currently used to charge portable devices but it shows great promise with respect to how it could soon be used for electric cars.
The charging process involves the use of electromagnetic induction to create electricity through a charging coil. The energy is transferred to the device through a receiving coil, thus charging the battery without any physical contact.
The main obstacle to using this technology is the size of the car itself. Most electric vehicles are a lot bigger than the portable devices that currently use induction charging. In that regard, a car-oriented inductive charging system would have to be more potent and reliable than virtually any other charger on the market today.
Needless to say, this form of wireless charging is still a long way from seeing any practical application to electric vehicles. However, it could hold the key to developing a self-charging electric car at some point in the future.
All Things Considered
The truth of the matter is that we’re still a few years away from having functional self-charging electric cars, but not for lack of trying.
As a matter of fact, most electric car manufacturers are looking into the possibility of coming up with a reliable way for electric cars to charge themselves on the go, or at least in a shorter time.
Such a system would not only improve the driving range of any electric car, but it would also help shorten charging times overall.
We hope this quick read helped you to better understand “why can’t electric cars charge themselves.”