The Million-mile battery – the future of electric cars

Published 7 August 2020
in Advice
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Plug in and charge your mobile phone enough times, and you’ll inevitably see the battery life get shorter.  The same is true for electric cars.

With mobile phones, a replacement battery is comparatively easy, and most users have a change cycle of around 2 years.  An electric car is a fundamentally different proposition on both fronts.  The cost of replacing a battery can be prohibitive, and with ‘range anxiety’ an issue for all drivers adopting the new technology of electric cars, the knowledge that the available range may actually decrease over time adds further uncertainty.  What is more, it can drastically impact the car’s resale value.

Warranties on electric car batteries are typically set at 8 years, or 200,000 miles.  There is now a move towards the worlds first ‘million-mile battery’.  Both Chinese battery manufacturer, Contemporary Amperex Technology, as well as American firm Tesla planning to launch their versions of this milestone in battery longevity.

In reality, the ‘million-mile’ tag is essentially a marketing ploy.  Very few car drivers will test this functionality.  The real benefit of the million-mile battery is that the technological advances required will help alleviate some of the other issues around battery life.

Any electric car owner will tell you that frequent fast-charging, cold weather and aggressive driving noticeably affect battery performance.  Even leaving a car with a fully-charged battery, rather than a partially-charged battery (80% is considered the optimum) can increase the rate of battery degradation.

As a rule of thumb, the battery will degrade around 2% per year, and once it falls below 80% of its starting value, it is generally thought to be no longer suitable of use in cars.

The key then is developing battery technology to mitigate this degradation.  Once again, Tesla are the undoubted market leader.  Much like their lead in mapping data for autonomous driving, Tesla’s advantage is down, in part, to the sheer volume of data their customers deliver to them on a daily basis.  

Direct experience of exactly how electric cars are used, and how they perform in different scenarios, climates and over longer periods of time is allowing researchers develop solutions to guard against some of the issues batteries currently face.

The holy grail of the 400-mile single charge range is now approaching.  As we predicted in 2018, this number will be the catalyst for the mass adoption of electric cars in the UK, and around much of the world.

Once this milestone is achieved, battery technology will be about how to manage the huge increase in usage, and therefore charging cycles, we will see as autonomous cars becomes a day to day reality.   If average car usage, or utilization, jumps from its current rate of around 4% to the expected 12-15% autonomous cars will bring, this brings a new hurdle in the battery technology race.