Battery technology update: is it a game-changer for the energy future?

Following BP's announcement earlier this year of its investment in a developer of electric vehicle batteries with the potential to charge in five minutes, BP Magazine looks at the technology today and its potential for the future with nine, AA battery-size, facts

1. Emerging technology

Put simply, batteries store energy in chemical form and convert it into electrical energy at the push of a button. Batteries have been around in some form for hundreds of years, from heavy lead acid blocks in vehicles to the small round discs in kitchen weighing scales.

So, why are they considered an emerging technology? Because we're now looking at batteries capable of being recharged thousands of times, lasting for many years and powering a two-tonne vehicle across the length of England – all of which requires capacities 100,000 times greater than the AA cell in your TV remote.

3. The raw materials

Around 90% of today's rechargeable battery market is based on old lead-acid technology, such as the starter batteries in conventional cars. The other 10% is dominated by lithium-ion batteries, or LiBs for short, which, at the moment, are the leading technology for use in smartphones and electric mobility.

These batteries require more than just lithium, though, with other materials used in the electrodes, including cobalt, nickel and manganese.

4. Storing and releasing energy

Energy and power density are often conflated, but it's important to know the difference. Energy density is the amount of energy stored in a battery.

In terms of electric mobility, the total energy that a battery can store relates directly to the range that the vehicle would have, i.e. the distance it could travel before it requires recharging. Therefore, the greater the storage capacity of the battery, the better the range of the car.

Power density is how quickly that battery can release its energy. For example, an electric car travelling at a steady, low speed could consume around 10-15 kilowatts (kW) of power, but, for acceleration, it could require hundreds of kilowatts, albeit for short bursts.

5. Falling costs

Until recently, almost half the cost of an electric vehicle was taken up by building the battery itself. With advances in technology, that cost has dropped in the past three years by about two-thirds to around $200 per kilowatt-hour (kWh). For a top-end car, the battery cost drops from around $45,000 to around $15,000.This reduction has helped to accelerate the take-up of electric mobility. And costs are expected to fall even more dramatically; BP’s Technology Outlook predicts that buying, running and fuelling electric cars in Europe will become competitive with ICE (internal combustion engine)-driven models before 2050.

6. Capacity versus charging speed

Battery life remains a problem, both for smartphone users with 'phone anxiety' who want power that lasts longer than a day - and for potential electric vehicle owners with ‘range anxiety’ (the fear of running out of energy mid-journey without the means to recharge). Those drivers may want to go farther than 200 miles on a charge but don’t have access to home charging to top-up the battery overnight. They want solutions. Charging rates for LiBs have remained stubbornly slow because of a trade-off between how much energy a battery holds and how quickly it can be charged. This means, at the moment, a battery is either designed for high capacity (energy density) that will allow the battery to last longer before recharging or, one that’s optimised for a fast charging rate. [For more, see 'the experts' view' below].

7. Finding the right chemistry

Almost all four-wheel battery electric vehicles these days use LiBs. But, battery developers are playing around with the fundamentals of the technology - the cathode and the anode (between which the electric charge moves) and the electrolyte solution (that carries the charge). They are hoping to discover the right combinations that will produce greater power and energy densities and, ultimately, could be a game changer for electric mobility.

9. Cobalt stocks

A ready supply of cobalt and lithium, key ingredients in batteries for electric vehicles, is a crucial factor in the growth of the EV market. So significant are these metals that data on their reserves and production levels are for the first time included in this year's BP’s Statistical Review of World Energy. 

The review found that, while lithium is fairly abundant, with the majority of proved reserves being held by Australia and Chile, cobalt supplies are less secure. Around 90% of the world’s reserves of this vital metal can be found in the Democratic Republic of Congo and the political and economic instability in the nation could hamper supply. However, this is providing momentum for the development of new, less cobalt-intensive technologies.

The experts' view: the pace of change

BP has experts from around the business looking at battery technology and its implications for electric mobility. Most recently, BP has said it believes ultra-fast charging is key to accelerating the adoption of EVs worldwide. Jon Salkend from BP's advanced mobility unit explains some of the thinking behind this view, while emerging technology researcher Bogdan Gagea reveals how BP is looking closely at the impact of electrification.