The range of an electric car

Published by on 12.12.2019 - 7 min

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“Range” refers to the distance an electric vehicle can travel before the battery needs to be recharged. What affects this range, and how can drivers optimize it? We give you all the advice and information you need about the range of an electric vehicle.

What determines the range of an electric vehicle?

The range of an electric vehicle depends first and foremost on the capacity of its lithium-ion battery, in other words the amount of electricity it is able to store. Expressed in kWh (kilowatt hours), it is equivalent to the size of the fuel tank in combustion-powered vehicles: it determines the energy reserves available to the engine and other elements of the vehicle.

Range is also affected by other factors that influence the speed at which the energy is consumed. Some, such as the energy efficiency or the power of the engine, are intrinsic to the vehicle. Others are related to how the vehicle is driven; this is the case for factors such as average speed, speed of acceleration, road topography, meteorological conditions, number of passengers, and weight of baggage carried in the trunk.

The difference between theoretical range and actual range

Two individuals driving the same car will not necessarily obtain the same range. This is why the range of electric cars is standardized.

Potential buyers need to be able to analyze and compare the range of different vehicles on the market. As a response, the automobile industry and several economic regulation authorities have designed protocols to test the range of different vehicles in standardized conditions intended to reflect real-life usage scenarios.

The latest version of this protocol is called WLTP, which stands for Worldwide Harmonized Light Vehicles Test Procedure*. It aims to provide values close to what a driver might experience in daily life, with a cycle including a combination of urban, suburban, and freeway travel.

How to optimize electric vehicle range

New ZOE charging Wallbox

Traditional combustion-powered vehicles begin consuming energy as soon as the engine is turned on. For electric vehicles, it’s slightly different: they consume electricity when their parts are required to work, but also recharge their batteries when slowing down thanks to regenerative braking.

To optimize the range of a Renault ZOE, for example, the driver must reduce energy consumption during acceleration and while maintaining speed, as well as take full advantage of the potential for recovering energy: this is a concept called eco-driving.

A high-speed trip on the freeway requires more electricity than a trip of the same distance on a highway. Likewise, accelerating abruptly when the light turns green requires more energy than a slow acceleration. But electric vehicles naturally provide rapid acceleration, so there is no need to slam on the accelerator in order to get out of slow-moving traffic.

It is also important to brake and come to a stop smoothly. Rather than hitting the brakes at the last moment, it is better to plan ahead and ease up on the gas to let the car slow itself down naturally, thus converting its kinetic energy into electricity. By doing this, each time the vehicle slows down, it recharges the battery and therefore extends the vehicle’s range! This smooth style of driving is also better for the few parts of an electric vehicle that are subject to wear and tear, such as the brake pads and tires.

Factors that affect range

While driving style has the most significant effect on the range of electric vehicles, the actual range also depends on factors including road topography, load, and use of heating and air conditioning.

Road topography

Driving up a steep hill requires a significant amount of energy, especially at a high speed. Reaching a ski resort, for example, requires a lot more of the engine (and therefore the battery) than traveling along flat roads, thereby decreasing the range. Driving downhill does offer some compensation however, as the vehicle will recharge its battery whenever the driver makes use of regenerative braking. With their particular topography, mountain journeys are the ideal opportunity to practice eco-driving!

The weight of the car

The heavier the car, the more energy is required to move it. The actual range is thus lower when there are four passengers in the vehicle or with a heavy load in the trunk. The impact is fairly moderate when using a smooth driving style, but it can become much more noticeable if the driver engages in frequent accelerations, especially at high speed.

New ZOE opened trunk

Use of heating and air conditioning

You often hear that electric vehicles’ range decreases in cold weather, but most vehicles have systems that are designed to keep the chemical processes of the lithium-ion batteries at an optimal temperature. Weather can, however, have an indirect effect on range, as extreme temperatures can cause the driver to use the heating or air conditioning. This is what motivated Renault to develop cabin preconditioning, available with the ZOE. Accessible through the MY Renault mobile application, this feature lets you program a desired temperature for the car, including when plugged in to its charging station, in order to avoid having to turn on the heating once you hit the road and putting a strain on the range of your vehicle.

Condition of the tires

It is one of the main financial benefits of electric vehicles: the lack of a clutch, transmission, and pistons reduces the need for regular monitoring, maintenance, and the replacement of parts subject to wear and tear. Nevertheless, if your tires are low on air, the suboptimal pressure can decrease your range. One more reason to check your tire pressure regularly!

Wear on the battery

Recent progress in lithium-ion technology ensures that your car battery will have a long life, even after sustained use. There is, however, a form of wear that can affect the capacity of the battery, and therefore the range of the vehicle, over time.

Battery rental is one possible solution, as it means that the manufacturer remains responsible for the battery for its entire life cycle. They will repair it or replace it as soon its capacity drops below a certain level, meaning the driver need never worry about a decrease in range or charging ability.

Rental is also favorable to the repurposing of second-hand batteries for other, less-demanding uses, thus participating in the creation of a true circular economy within the electric vehicle industry.

What is the outlook for electric vehicle range?

Future of Renault electric cars

With a range of 395 km in a WLTP* cycle, New Zoe already allows drivers to use their cars for standard everyday travel with only once-weekly charging. In addition to seeking to increase battery capacity, Renault is working on improving the energy efficiency of its vehicles and developing ways to simplify access to everyday charging.

The most recent Renault ZOE generation, for example, introduced rapid DC charging at capacities of up to 50 kW, allowing it to recover up to 150 km of range in a mixed cycle in just 30 minutes. In addition to the numerous AC charging options offering up to 22 kW, this rapid charging feature makes New ZOE the most versatile in terms of charging on European infrastructures.

The next generations of electric car batteries

While lithium-ion technology is the standard for 100% electric and hybrid vehicles today, scientific progress may one day result in the creation of new batteries capable of offering much greater ranges than what we are accustomed to today. Notably, research is being done into the idea of a solid state battery, which would increase both the storage capacity and the stability of the lithium-ion cells.  Hydrogen fuel cells, meanwhile, are also worth investigating as a complement to lithium-ion batteries, although they do represent new challenges related to the distribution and storage of hydrogen under pressure.

 

*The duration and distances mentioned here are calculated from results obtained by the New ZOE during the WLTP (Worldwide Harmonized Light Vehicles Test Procedure, standardized cycle* (57% urban driving, 25% suburban driving, 18% highway driving,) which aims to represent the actual conditions of a vehicle’s use. However, they cannot foresee the type of journey after recharging. The recharging time and the recovered range also depend on the temperature, battery wear, power delivered by the charging station, driving style, and level of charge.

Copyrights : Jean-Brice Lemal, OHM Frithjof, Romain Laurent