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Key things to know about an electric vehicle battery

By Chris Mirams |

Electric vehicles might only have about 20 moving parts with the most important, and expensive, being the battery. According to the International Energy Agency, the world could see 145 million electric vehicles, vans, heavy trucks and buses on the road by 2030, a mind-boggling leap from the 10 million in 2020. Here are some of the key things to know about the EV battery.

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How does an electric vehicle battery work?

First commercialized in 1991, the lithium-ion battery was initially developed for the consumer electronics sector. Eventually it become standard for all devices requiring a portable rechargeable battery such as smart phones and laptops. Most electric vehicle batteries are lithium based and rely on a mix of cobalt, manganese, nickel, and graphite and other primary components. EV’s use a traction battery pack to store the electricity used by the motor to drive the vehicle's wheels. The traction battery pack is what you charge, and its efficiency helps determine the overall range of the vehicle. The battery pack sits below the cabin of the vehicle and runs along the length of the car. In plug-in hybrid vehicles (PHEV), the main difference is that the battery also has a combustion engine. PHEVs run on electric power until the battery is depleted and then switch over to fuel which powers an internal combustion engine. The combination of battery and fuel gives PHEVs a longer range than their all-electric counterparts. A battery management system (BMS) controls the output, cooling and monitoring functions.

Who makes EV batteries?

Four battery makers and suppliers currently supply 69% of the global electric vehicle market - LG Chem, Panasonic and Contemporary Amperex Technology Co (CATL). China’s CATL supply BMW, Honda, SAIC Motor Corp., Stellantis, Tesla, Volkswagen and Volvo. LC Chem supply General Motors, Groupe Renault, Stellantis, Tesla, Volvo and VW. Panasonic work with Toyota and Tesla.

How many types of electric vehicle battery are there?

There are two common types of EV battery – lithium-ion and nickel-metal hydride. Lithium based batteries hold a lot of energy for their weight, which is vital for electric cars – less weight means the car can travel further on a single charge. Lithium-ion batteries also have a low “self-discharge” rate, which means that they are better at holding a full charge over time. Nickel-metal hydride batteries are more widely used in hybrid-electric vehicles but are also used successfully in some all-electric vehicles. They have a longer life-cycle than lithium-ion or lead-acid batteries.

What size EV batteries are there?

Battery size is measured in kilowatt-hours (kWh). The more kWh a battery is rated for, the more energy it can store and the further the EV can drive on a single charge. So, the more kWh the battery capacity has, the longer the vehicle range and the bigger the price. For example, a 2021 Nissan Leaf has a 40kWh battery and an approximate range of 270km, whereas a 2021 Hyundai Kona Elite Series II EV has a range of around 484km due largely to its larger 64kWh battery.

How long does an electric vehicle battery last?

Like any battery, including the one in your mobile phone or laptop, the batteries in electric cars will lose some of their capacity over time. The batteries go through cycles of 'discharge' that happen when driving and 'charge' when the car is plugged in. Repeating this process over time affects the amount of charge the battery can hold. Most manufacturers have a five to eight-year warranty on their battery. However, as the technology continues to evolve quite quickly, many are predicting an EV battery will have an average life of 10 – 20 years before it’s needed to be replaced. The health of the battery can be checked on some of the more established electric vehicles using a data reader that can be plugged in to the on-board diagnostics port. Apps like Leafspy (for Nissan Leafs) and EVBATMON (for Mitsubishi Outlander) can be used to estimate the remaining accessible battery capacity (or how much degradation has happened).

 

How to make your EV Battery last longer

  • Charge the electric car battery between 20%-80%. The lifespan of the battery pack can depend on how much it’s charged. You can extend the life by only charging them between 20% and 80% and try not to let it drop below 50% too often.
  • Avoid overcharging. You don’t need to charge your EV overnight, every night. Overcharging can cause chemical changes inside the battery that could impact how efficiently it can store energy. Ultimately, you are looking to reduce the number of charging cycles that your battery goes through in its lifetime.
  • Reduce exposure to extreme temperatures. Extreme cold or heat can negatively affect your car’s battery and therefore the range you can travel

Find out more about charging your EV at home

Regenerative braking

The energy that’s stored in your EV battery is used to power the electric motor while driving, so it’s usually in a state of discharge when you’re behind the wheel. But there’s another key component to EV battery design called regenerative braking that helps you recharge the battery while the car is in motion. Regenerative braking, or regen for short, can be found in both BEVs and HEVs. It uses the kinetic energy produced by your brakes to recharge the battery, saving as much as 70% of energy that would otherwise be lost.

How much does it cost to replace the battery in an electric car?

A new battery, depending on its size, presently costs at least $5,000 to $10,000, but prices are falling. As technology improves, you may be able to buy a battery with more capacity than the car initially came with. You may also need to only replace individual dead cells, at a lower cost than a full replacement.

How safe is an EV battery?

While the manufacturing process of batteries continues to be refined, the main battery used in EV’s, lithium-ion, has had its moments. You may recall laptops and smart phones catching fire in years gone by and there has been similar concerns around EV batteries. Even when EV batteries are operating normally, they still generate vast amounts of heat. Without significant cooling, the batteries would suffer from a high risk of catching fire. To prevent this, most EVs use extensive cooling systems that use liquid coolant to pull heat away from the batteries, similar to the radiator in your petrol car. To help mitigate risk if there’s a crash, car supplier Bosch developed a system that disconnects the battery pack by blowing apart sections of wiring immediately following an accident to help make rescue and escape shock-free. In early 2021, China introduced a new mandatory regulation to cover the main causes of thermal runaway or fires in batteries. The new regulation emphasises an improvement in battery system safety regarding thermal diffusion, external fire, mechanical shock, simulated collision, thermal and humidity cycling, external short circuit, overcharge and over-temperature. Until now specific EV safety regulations have been voluntary which has led to a wide variety of battery design and thermal management strategies across the various EV sectors. The move by China, may lead to more standardised solutions.

Can EV batteries be recycled?

Battery designs are not standardised, and some were not designed with recycling or dismantling in mind. There is existing technology to recycle lithium-ion batteries which involves either shredding or freezing to recycle the metals, but the industry is trying to figure out how to do this at scale. EV batteries are larger and heavier than those in regular cars and are made up of several hundred individual lithium-ion cells, all of which need dismantling. Damaged cells can go into a state of thermal runaway, which could cause the battery to catch fire or explode. Beyond that, separating ingredients of lithium, nickel, manganese and cobalt is complex.

 

It’s believed only about 5% of lithium-ion batteries are currently recycled. Regulation is being shaped in some countries, including the European Union, to ensure car manufacturing companies look to recycle cars and componentry nearing end of life. Some aren’t waiting for regulation. Nissan, for example, is now reusing old batteries from its Leaf cars in the automated guided vehicles that deliver parts to workers in its factories. Volkswagen is doing the same and has also recently opened its first recycling plant and plans to recycle up to 3,600 battery systems per year during the pilot phase. Our nearest specialist to dismantle EV batteries is Envirostream in Australia and whether a full-scale battery recycling operation could start in New Zealand comes down to economies of scale.

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