Electric vehicles (EVs) have captured the country's attention, with more hybrids and pure EVs selling now than ever. While the cars are expensive up-front, owners face lower operating costs in the long term, as electricity is less expensive than gasoline. USA Today even reported that EVs could help their owners obtain cheap car insurance. Though wildly popular, the vehicles still face a number of hurdles, one of them being the dip in performance that EVs experience in the cold weather.
Why do EVs lose range in the cold?
The lithium ion battery inside every EV allows the car to run without gasoline. It's identical in many ways to the battery in your smartphone - just much bigger. Batteries perform worse overall in the cold weather, and there are some issues specific to EVs that cut range even further.
1. Energy uptake and output are limited when a battery is cold, according to MIT Technology Review (MTR). This means that the speed at which a battery can uptake energy - or charge - and the speed at which the battery can output stored energy is limited. The latter means that acceleration is significantly reduced from a cold battery. Different manufacturers have different approaches to the problem, some of them heat the battery electrically, while some use the motor's waste heat. Both have disadvantages. Heating the battery electrically takes away from energy that would otherwise go toward driving, shortening the range of the car on one charge. Using the motor's waste heat is more efficient, but this takes time, meaning that for several minutes the EV can't reach full acceleration.
2. Regenerative braking is used in hybrids and EVs to recover energy that is lost when the brakes are applied. This runs a lot of energy through the battery, which can be damaging at low temperatures. Because of this problem, some EVs have to disable regenerative braking until the battery warms up, which causes a greater loss of energy. Users can limit this loss by charging their car just before it is used, but this isn't always possible. Allowing the car to slow naturally, with as little use of the brakes as possible, could also help conserve some of this energy.
3. Heater use for the interior of a car is the biggest drain on an EVs' range. While the internal combustion engine of the average car naturally produces a lot of waste heat (which is used to heat the car's interior) EVs produce very little waste heat. In order to keep the interior of an EV toasty warm, energy has to be drawn from the battery to power an electric heating element. Instead of turning on their heaters, EV owners are reportedly bundling up or making due with seat warmers in an effort to preserve their car's range.
Solutions in the works
EV manufacturers are working on solutions, but most are still years away according to MTR. In order to improve range, MTR reported that companies are looking for ways to safely increase the conductivity of the battery's electrolyte or reduce the size of the electrode's particles. The U.S. Department of Energy is also funding research of thermal storage materials that could more efficiently heat the interior of vehicles. The solutions are out there, but it will take some time before we're all driving EVs, even with the cheap car insurance.