As BP announces its investment in a developer of electric vehicle batteries with the potential to charge in five minutes, the company looks at the technology today and its potential for the future
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.
Innovative applications
Batteries are being used alongside other emerging technologies in areas such as robotics and renewable energy. Research is underway into how batteries can be used to store energy to balance out the intermittent output of renewable energy plants.
Batteries are also transforming expectations of what?s possible with electric vehicles (EVs). Their use in the area of electric mobility has arisen as the world looks for lower-carbon transport solutions. Customers want fewer emissions, along with improved fuel efficiency. Battery technologies may provide the answers for both.
According to BP?s Energy Outlook, by 2040, more than 30 per cent of kilometres travelled by passenger cars could be powered by electricity.
The raw materials
Around 90 per cent of today?s rechargeable battery market is based on old lead-acid technology, such as the starter batteries in conventional cars. The other 10 per cent is dominated by lithium-ion batteries (LiBs), 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.
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 10-15kW of power, but, for acceleration, it could require hundreds of kilowatts, albeit for short bursts.
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 US$200 per kilowatt-hour (kWh). For a top-end car, the battery cost drops from around US$45,000 to around US$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 internal combustion engine (ICE)-driven models before 2050.
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 LiB 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.
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.
In Norway, electric and hybrid vehicles now account for 52 per cent of all new car sales
Fast-charging future
Fast-charging batteries could encourage more car owners to make the switch to an electric vehicle.
Start-up companies, such as BP-partner StoreDot, which is using a new type of electrolyte and nanomaterials in LiBs, could potentially provide car manufacturers with a battery that can be charged in five minutes or less.
This technology, along with accessibility to a nationwide charging network, could speed up the adoption of electric vehicles.
Jon Salkeld, technology director, BP?s advanced mobility unit, says, ?More than half of the world?s population doesn?t have access to charging at home, so they need to charge elsewhere. Also, as we see less personal home car ownership and an increase in fleet-owned cars, not everyone will be able to plug in their own cars in their own garages to charge overnight.
?Home and destination charging are certainly part of the mix, but the adoption of ultra-fast-charging is key to making EVs accessible to all, be they personal drivers or big fleets.?
Bogdan Gagea, researcher, emerging technology group, adds, ?We are working to understand the rate of development of battery technology and future trends so we can incorporate this into our long-term outlook for the transport sector.
That, in turn, helps us to understand liquid fuel and lubricant demand in different markets and how that might be impacted by electrification. Ultimately, we want to understand our customer.?
