It may seem like we’re living in a science fiction reality and asking questions like can electric cars charge themselves is completely warranted. We’ve come so far in terms of transportation and it’s easy to imagine that we’ve already overcome any obstacles that get in the way of our electric cars charging themselves.
Yes – technically, electric cars are capable of charging themselves—but only a little bit. While getting a full charge while driving is still only possible in our dreams, that reality could be closer than we think.
Unlike in a conventional car, electric cars don’t come equipped with the components required to charge the battery while driving. However, they do come with something different, an ability to charge the battery while braking.
We’ll explore this a little more and let you know how regenerative braking currently falls short and how we might see electric cars charge themselves in the future.
Self-Charging Electric Cars
As far as questions about electric cars go, one of the most popular is if they can charge themselves. Electric cars have come far over the past couple of years, but self-charging varieties are generally only seen in sci-fi books and movies. Yes, conventional cars can charge their battery while driving, but this isn’t something that’s seen in electric vehicles.
If you’re an auto buff, you may be familiar with alternators. In conventional petrol-fuelled cars, the alternator is responsible for charging the battery as you drive. It’s a type of generator that creates, as the name suggests, alternating current (AC). As you drive, a belt attached to the car’s engine spins a pulley that is connected to the alternator. The energy produced by the fossil fuels in the car creates mechanical energy which is converted to electrical energy (plus heat, noise, and vibration and this current flows into a set of coils.
The flow of the AC alternates between north and south and must be converted to direct current (DC) before it can be used to charge the battery of the vehicle. This happens through a diode, a semiconductor that directs the flow of the current so that it travels in a certain direction—think of it like a one-way street. Once the AC has all been directed in the same direction, it just needs to pass through a voltage control circuit to ensure that the voltage is appropriate for charging the battery.
In an electric car, however, there is no engine and there is no mechanical energy. If we were to create spin with the electric motor, we would essentially be using electricity to make electricity, and we would end up losing some as noise, vibration, and heat.
However, there is a way we can convert some of the energy produced in an electric car to electricity to charge the battery.
Everything we’ve talked about has involved converting some type of energy (namely, mechanical) into another type of energy (namely, electrical). Electric vehicles have another type of energy that can be used to charge the battery—potential energy. When coasting down a big hill, potential energy can be converted to kinetic energy (feel like you’re in a high school physics class yet?).
Regenerative braking has commonly been used with a range of electric transportation devices that include electric skateboards, scooters, and bicycles. When the brakes are applied, that kinetic energy has to escape somewhere. Most times, it’s just released as heat into the environment.
However, when there is some capacity for a battery to be charged, it can go through a similar process as what occurs with an alternator. The energy is captured and transformed into a current that can be sent back to a battery that has capacity for it. If the battery is already charged, however, the energy is released, or, when it comes to some vehicles, can actually do damage to the battery itself.
Regenerative braking is used and does work in electric vehicles. However, it’s difficult to say if this process is actually charging the cars themselves, or simply improving their efficiency.
Across different electric cars, there’s a variation between the efficiency of regenerative braking (remember, some is lost as heat, sound, and vibration). Estimates show that efficiency rates are generally around 60-70%. What exactly does this mean for drivers? Well, Tesla Model S drivers have reported that regenerative braking has allowed them to recapture up to 32% of their total energy while driving up and down hills.
Regenerative braking depends heavily on the weight of the cars, and as such, works better for larger electric vehicles (more kinetic energy). It obviously requires extended braking (i.e. long hills), too. While we can’t expect to get a full charge from regenerative braking anytime soon, a range increase is a range increase—even if it’s only around 5%.
Futuristic Charging Scenarios
From adding a wind turbine to mounting solar panels on the roof of the car—electric vehicle manufacturers and enthusiasts have come up with some pretty futuristic ideas for how electric cars can charge themselves. Although things like solar panels on the roof may contribute to powering certain functions, we currently aren’t using these practices to fully recharge the battery. That said, however, we could see some exciting and innovative charging methods used in the future.
In Hyundai’s dream for a transportation future, electric cars will take control of their own charging—using intelligent and autonomous design to literally “plug themselves in.” As the future is anticipated to become increasingly saturated with electric vehicles, Hyundai has joined many other manufacturers and pundits who predict an increase of autonomous vehicles, too.
In Hyundai’s case, they not only anticipate vehicles that can autonomously drive, but can also autonomously charge, too. Once 5G networks become fully operational, Hyundai thinks that a car could be capable of heading to a charging location sans driver. This will require both a vehicle and an infrastructure that is intelligent, as well as magnetic induction so that the charging can be wireless, too.
Sounds pretty futuristic but who knows—we may be closer to this than we think.
Making use of some of the same technology that would be incorporated in the magnetic induction charging stations dreamed about by Hyundai, researchers at the University of Colorado have also predicted a future where charging plates located in the road could charge the onboard battery wirelessly. In this future, one could drive hundreds or perhaps even thousands of miles without having to plug in.
Researchers see future highways that would have one lane dedicated to charging. An electric car would simply drive in that lane when it was in need of a charge. As a result, a smaller battery would be required, and electric cars could be cheaper as a result. The charging pads would be positioned every couple of meters, that way the vehicle could receive a charge consistently.
Wireless power transfer is already a feature in many warehouses and while we’re still far off from a future where this technology is used for on-road charging, it’s beginning to look less like an impossibility.
An Electrified Future
Electric cars have come a long way in the past couple of years. They’re faster, they can go further, and they’re more accessible to the average person. While electric cars currently can’t fully charge themselves, on the go charging may be something we experience in the future—even if we’re not driving down big hills. You never know, one day it might be as simple as driving down the highway to recharge the battery. If our wildest and most futuristic dreams come true, the electric cars of the future may be able to literally charge themselves one day, too.