The internal combustion engine, conceived in the 17th century and perfected in the 18th, rightfully sits on the leaderboard of modern inventions. For centuries, it provided the moving force for locomotives, planes, vehicles and heavy machinery — literally turning the wheels of the industrial revolution. Its descendant, the electric motor, today lies at the heart of another revolution: the electric vehicle (EV). Instead of fossil fuels, EVs are powered by clean electricity from a battery. But what exactly are these batteries, and how are they different?
What uses an electric battery?
Although an electric battery is closely associated with EVs, the truth is that most vehicles use batteries. Traditional cars included. Here, they pump electricity to peripheries like headlights and wipers, as well as to the central console. But their prime purpose is to fire the starting system. Ever sat in a car that just won’t start? That’s a fault with the battery — they jolt the car into life, before letting the internal combustion engine take over.
In all-electric vehicles, the internal combustion engine is gone. In its place is an electric traction motor needing a battery. Like an engine, it supplies a steady flow of power to the electric motor, propelling the car forward. These batteries are similar in purpose and material to those in electronic devices, only much larger. But like such devices, these batteries must be plugged in and recharged periodically.
As the name suggests, plug-in hybrid vehicles like the Toyota Prius use both electricity and combustion. They run first on electric power until the battery is depleted, before switching to traditional fuel that powers an internal combustion engine.
What are batteries made of?
EV batteries typically use elemental combinations, like nickel-cadmium or nickel-metal hydride. The most popular of these by far is lithium-cobalt, a type of lithium-ion. Its exceptional power and safety profile has helped kick EVs up to comparable performance with conventional cars.
With more EVs on the road (23 million by 2030, according to the International Energy Agency), the demand for raw lithium will explode. Indeed, a UNCTAD report predicts the market for one component of the lithium battery will increase almost ninefold — from an estimated $7 billion in 2018 to 2018 to almost $60 billion by 2024.
This creates a knot of questions on how this volume of lithium can be sustainably sourced and mined — a powder keg issue due to current geopolitics: half of the world’s lithium reserves lie in the troubled DRC.
How does the battery affect range?
The battery, above all, determines the range of an electric vehicle. This is followed by other (related) variables like external temperature and driving style. Concerns about how far an EV can travel on a single charge represent an enduring challenge to market adoption: so-called ‘range anxiety’. A 2016 study from MIT and the Santa Fe Institute proved these fears as disproportionate to reality, but new batteries are nevertheless stretching the upper limits of EV range.
Being electric, old (and seriously antiquated) units like horsepower go out the window. Ready for some stats and figures? For power, electric cars instead use kW, and battery capacity is measured in kilowatt-hours (kWh). A battery rated at 100 kWh can deliver 100 kW for one hour, 50 kW for two hours, or 1 kW for 100 hours. To wrap this around an example; the Tesla Model S 75D has a 75 kWh battery, and a realistic range of around 230 miles (370km). This means the car uses 32.6 kWh of electricity on average per 100 miles.
So how far will a full charge take you? Modern batteries normally cover between 150–300 miles (240–480 km) — in most cases enough for a single long-distance trip, or a couple of weeks of commuting. Range improves, of course, with newer models. The 2020 Tesla Model Y Long-Range can travel as far as 316 miles (508km), and the mid-market Nissan Leaf Plus 226 miles (364km).
How long does a battery last?
Ever kept a smartphone for several years? You might have noticed it doesn’t hold charge like it used to. That’s unavoidable. Due to simple chemistry, prolonged use of any battery will wear out its conductor and result in degradation. EV batteries aren’t immune to this, but the extent is less dramatic than you might think.
A tool created by telematics fleet-management company Geotab weighed data from 6300 EVs. It shows that despite an early drop, the rate of decline slows in later years, averaging at a loss of 2.3% energy storage per year. What’s more, the vast majority of batteries will actually outlast the usable life of the vehicle itself.
Like we mentioned earlier, EV batteries are shark-sized versions of phone batteries. But phone batteries are designed by companies who want customers to buy a new model every few years. This, obviously, doesn’t apply to EVs — who need to represent a viable replacement for traditional vehicles. Modern EV batteries will ordinarily last between 10– 20 years, with major manufacturers often offering a generous guarantee.
The battery, for decades a background character in car propulsion, has become the star. Better, more capacious batteries have spurred the electric car revolution into full gallop. While sticky questions remain on how new materials can be responsibly mined, we stand before a steep trajectory of battery power, range and adoption. For proponents of electric transport, the best is yet to come.