Electric vehicle batteries: what you need to know

Your EV battery questions answered

What type of batteries do EVs use?

EV batteries have come a long way from the lead-acid batteries they originally used. Modern EVs feature many single cells stacked together to form one large battery that’s often placed beneath the floor of the vehicles’ chassis in a ‘skateboard’ configuration.

Most modern EVs use a lithium-ion (Li-ion) battery, while many EV hybrids use a nickel-metal hydride (NiMH) battery. Many automakers are also working on solid-state battery technology.

What is a lithium-ion EV battery?

A lithium-ion EV battery is a much larger version of the battery used in your mobile phone. Lithium-ion batteries recharge quickly, maintain power for long periods of time, provide consistent voltage, and are robust against moderate temperature changes. That said, they are costly to produce. Extreme temperatures can affect their charging and discharging, and leaving lithium-ion batteries fully charged or discharged for long periods of time can be detrimental to their lifespan.

What is a nickel-metal hydride EV battery?

Many plug-in hybrid vehicles (PHEVs) use a nickel-metal hydride (NiMH) battery. NiMH batteries are long-lived, durable and compact. That said, they have a much smaller capacity (driving range) than lithium-ion batteries. PHEVs don’t need a large battery capacity, because the internal combustion engine (ICE) is used on longer journeys. They do, however, need a good lifespan, since hybrid vehicles cycle the battery from full to empty (and back again) every few miles.

What is a solid-state EV battery?

Solid-state batteries are an emerging technology that some automakers are investing in. These EV batteries could deliver more range in a more compact package with less cooling requirements. They use a solid electrolyte instead of the liquid or polymer gel electrolyte found in lithium-ion batteries. For now, however, large-scale battery production favours lithium-ion batteries.

Most pure EVs use a lithium-ion battery. Image: Ben Weinstein

How do EV batteries work?

In ICE vehicles, petrol or diesel is burnt to power the car. EVs are instead powered with the electricity produced from its battery.

A lithium-ion EV battery needs to be charged from an external power source, like a mobile phone or laptop. It charges by moving electrons from one electrode to the other, creating chemical changes inside the battery. When you drive, the battery discharges by moving the electrons in the opposite direction, which produces an electric current that powers the motor.

What is the lifespan of an EV battery?

An EV battery’s minimum life expectancy is the number of years listed on the manufacturer’s warranty. Most car manufacturers currently offer an eight-year battery warranty, but you can realistically expect an EV battery to last over 10 years, but their capacity will reduce over time.

Here are some of the most popular EVs in Australia with their battery warranties:

• GWM Ora – 8 years or 100,000km 

• BYD Atto 3 – 8 years or 160,000km

• MG4 – 7 years or unlimited mileage

• Tesla Model Y – 8 years or 192,000km

• Tesla Model 3 – 8 years or 192,000km

Battery Electric Vehicles (BEVs) need to be charged from an external source. Image: Supplied

Are EV batteries safe?

Modern EV batteries are very safe. EVs are tested by safety experts like ANCAP before they’re released to the public, and car manufacturers must follow safety regulations to protect drivers. In fact, lithium-ion EV batteries are safer than many ICE cars, which drive around large amounts of flammable petrol or diesel.

In the very unlikely event of a lithium-ion battery fire, you will need to ring 000. Never attempt to extinguish a lithium-ion fire yourself.

What does an EV battery’s capacity mean?

An EV battery’s capacity tells you how much energy the battery can store. Just like a fuel tank in an ICE vehicle, the bigger the capacity, the larger your possible driving range (and the steeper the price).

EV battery capacity is expressed in kilowatt-hours (kWh). For example, a 100kWh battery could supply a maximum of 100kW of power in an hour. But EVs will rarely use their full battery capacity. Instead, EVs throttle their power to last several hours and hundreds of kilometres before needing a recharge.

EV battery capacities usually range from 20kWh to 100kWh. Here are some of the most popular EVs in Australia, with their standard model’s battery capacities and driving ranges:

• GWM Ora – 48kWh (310km claimed range) 

• BYD Atto 3 – 49.92kWh (345km claimed range)

• MG4 – 51kWh (350km claimed range)

• Tesla Model Y – 57.5kWh (455km claimed range)

• Tesla Model 3 – 57.5kWh (491km claimed range)

The actual driving range of an EV can be affected by your driving behaviour. High speeds, fast acceleration, heavy cargo will use up more energy more quickly. Conversely, regenerative braking recovers energy to improve your EV’s range.

The Telsa Model Y is currently the most popular EV in Australia. Image: Supplied

How do you charge an EV battery?

Charging an EV at home or on the road is simple: all you need to do is plug your EV into a designated EV charging station. The higher the charging station’s kilowatt (kW) rating, the faster they’ll charge your EV.

At home, dedicated EV charging stations can charge up your EV in a few hours and be set up to use excess solar energy. On the road, there is a rapidly growing network of public charging stations across Australia.

What happens if my EV battery runs out of charge?

For some electric models, entirely discharging your EV battery (‘deep discharging’) may be harmful for the battery, causing it to deteriorate quicker and reduce its future ability to hold charge. Thankfully, it’s unlikely that you will drive until your EV battery is entirely run out of charge - just like most drivers don’t drive their petrol or diesel car until it’s completely empty of fuel.

With the average Australian motorist driving an average of just 35 kilometres per day, EVs on sale in Australia typically have enough battery capacity for days of driving before requiring recharging.

Charging an EV is relatively simple. Image: Ben Weinstein

What happens if my EV battery dies?

In the unlikely event that your EV battery reaches the end of its lifespan, where its remaining capacity isn't sufficient, you may need to replace the battery. 

While EVs are generally cheaper to maintain than ICE vehicles since they have fewer moving parts to service, EV batteries can be expensive to replace.

How do I take care of my EV battery?

To preserve your EV battery life, some EV manufacturers advise to keep your state of charge between 20 and 80 per cent. This keeps the battery at an optimal resting state of charge. New batteries found in some Tesla and BYD models do not require this charging behaviour.

Otherwise, you can take care of your EV battery just like an ICE car battery. Drive your car regularly to maintain its overall health, undertake maintenance in line with OEM recommendations, and minimise the vehicle's exposure to very high or low temperatures.

Aim to keep your EV battery charged between 20 and 80 per cent. Image: Matt Harvey

Can EV batteries be recycled?

It is possible for both hybrid and pure EV batteries to be recycled.

Lithium-ion batteries can be repurposed for powering homes or commercial buildings, since they retain a large amount of their original capacity. After the end of their working life, many materials in lithium-ion batteries can also be recycled, such as nickel, copper, plastic and lithium.

Car manufacturers are working on improving EV battery recycling. Volkswagen, for example, has announced a pilot plant in its home market of Germany for recycling 97 per cent of EV battery components to create new batteries.