The battery is arguably the most important aspect of an EV.

More electricity packed into a battery means you can drive your EV for longer without worrying about finding a charge point. It requires thousands of times more energy than our consumer electronics, it needs to be lightweight, and it needs to be safe.

The same battery that powers our phones and laptops also powers EVs.

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How do batteries work?

Batteries exploit chemical reactions between two metals (called ‘electrodes’) separated by another material (usually a liquid called the ‘electrolyte’ which is used to separate the two metals and allow the flow of charge) to create electricity.

The combination of the two electrodes and electrolyte leading to chemical reactions can be called battery chemistry. By fine tuning this battery chemistry, researchers can improve their performance.

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What battery does your EV have?

We are all familiar with single-charge batteries that we use in our TV remotes or small devices like clocks and radios. They undergo a permanent change after being used and will need replacing. Rechargeable batteries can be reused because supplying electricity to an empty battery reverses the chemical reaction, giving it a ‘charge.’

Read here for an in-depth explanation on batteries used in Electric Vehicles (EVs).

At the moment, there are three main battery chemistries in rechargeable batteries: nickel-based (NiCd, NiMH), lead-acid, and lithium-based.

Most EVs use lithium-based batteries because they are without competition; others are either too heavy with a lower energy density or they self-discharge overtime. In comparison, lithium batteries are efficient (>95%), they have low discharge rates, they have high output and are lightweight (with 2-5 times more energy density) which means more of them can be packed into an EV without making the vehicle too heavy.

Current lithium ion batteries use a combination of lithium, nickel, cobalt, and manganese as they offer the highest energy density.

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What next?

Battery manufacturers are always increasing the energy density of lithium batteries, so increasing battery capacity should not be a problem. However, one of the biggest obstacles to EV adoption is costs.

Despite their stellar performance, lithium battery costs are fairly high and can be as much as a conventional car. In the past 10 years, the average cost for an EV battery has reduced significantly by more than 85%—US$1100 (£850)/kWh in 2010 compared to US$156 (£120)/kWh in 2019 and now about $135/kWh in 2020. Battery manufacturers are constantly looking into more cost-effective methods, so this is surely set to drop further to US$100 (£77)/kWh by 2023. Can we expect an even more significant price reduction? Absolutely!

Lithium batteries are not all made the same—there can be varied to give them certain advantages and specific uses. EV batteries in Europe use nickel and cobalt both of which have price, supply, and ethical concerns. A lesser used LFP (lithium iron phosphate) variation, while does not offer the same performance, is significantly cheaper to scale up and may be the point of interest in the upcoming Tesla Battery Day as it is set to start a revolution of affordable EV.

As EV batteries reach their end of first life, they can be reused in other places like a solar farm, recycled to extract valuable nickel and cobalt metals or disposed of. Recycling EV batteries is tricky because the process is energy intensive and requires specific knowledge of battery chemistry which are often kept secret. Things are not all doom and gloom however, there is an economic and environmental drive for recycling, and we are seeing an increasing number of projects such as the Reuse & Recycling of Lithium Ion Batteries (ReLiB) tackle such problems.

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Lithium batteries are (not) always dangerous

Many are also concerned with safety.

The electrolyte used in lithium batteries is highly flammable and is a risk if it escapes the packaging and exposed to heat. But they can be and already are safely managed by battery management systems and that is not stopping advancements in safer batteries.

In 2021, BYD has also announced their ‘Blade Battery’ which offers a novel packaging method for LFP-based batteries that promises not only increased safety for the driver but also increased longevity and higher energy density than other LFP-based ones. Samsung has hinted at the possible answer to our problems with solid-state batteries which completely removes any safety risks and offers increased energy density. Unfortunately, it is still early days and far from being implemented on a wide scale.

As an EV driver (or potential one), it is also natural to worry about the capacity or the charging times for your vehicle. Let us have a look at battery capacities of current EVs. Most EVs seem to range between 40kWh to 70kWh capacities with more expensive options sporting 90kWh and above (e.g. Tesla Model S Long Range).

For example, using a VoltShare HH1 rated at 7.4kW, this translates to about a minimum of 2.5 hours of charging and a maximum of 4-6 hours for a 30-80% charge. Depending on the actual range of your EV, you may well have enough range for a short trip with as little as 1 hour of charge!

As the EV world may move towards lower EV capacity with LFP-based batteries but at much lower costs, choosing the right charger is more important now than ever. More public chargepoints are crucial for the next step forward and our community charging network augments current charging infrastructure and ensures affordable and convenient charging for everyone.