Inside Formula E's New Battery
Formula E, which has an audience of 200 million, is keeping its battery tech under wraps, but all the clues point to one breakthrough metal
At the Monteblanco racetrack in Spain, behind closed gates and away from the press, some of the world's largest racing teams rolled out a new generation of electric cars for a two-day test in March.
Behind each driver, encased in fibre glass, was the world's most advanced battery pack, designed to be driven at high speeds on bumpy streets in the next season of Formula E, an all-electric championship launched four years ago that is already rivalling Formula One as the most exciting motorsport.
Electric cars are not ideal for racing. Though clean, they lack the growl of F1 engines and instead sound like a washing machine on full spin. Recharging is also less easy than filling-up with petrol, so drivers jump into new cars mid-race.
Yet the buzz around electric cars has pulled-in the world's largest carmakers, including Renault, Audi and Jaguar, for races around the world's most fashionable cities, including Rome, New York and Berlin. F1 has a huge fanbase of 1.4bn, but has earned a reputation for gridlock and no overtaking, whilst Formula E has improved each season, lifting it audience from 65 to 200 million. Porsche, Mercedes-Benz and Aston Martin all want to field new teams.
Driving those gains is the battery technology, which began in Formula One. Williams, one of F1's longest-standing teams, invented a flywheel system that captured energy from braking, converting it into an electrical boost, catapulting cars out of corners and into the straights. Williams rolled-out the technology commercially before selling it to GKN, an $11bn engineering group based in the UK.
Over wine, linguine and pistachio biscotti at an Italian restaurant in Paris a group of politicians and motorsport bosses, including former Ferrari boss Jean Todt and EU commissioner Antonio Tajani, had meanwhile agreed to launch an electric version of Formula One, and Williams was commissioned to build the batteries.
It was given six months to make a prototype and only a year to be race-ready, but in the first season, each car covered a distance greater than the circumference of the earth, powered by batteries that could keep an iPhone going for 13 years.
The improvements since show the pace of change. Battery design is a tradeoff between power, range and fire safety, but in four years, speeds in Formula E have risen from 137mph to 186mph, whilst range has more than doubled from 17 to 39 laps.
Each team is allowed to build its own motor and gearbox, but every car has an identical battery, accounting for a quarter of the car's weight, which Williams designed for the first four seasons. It then lost the tender to McLaren, which has been given two years; the technology is moving so fast, race organisers have shortened the contracts they are handing out.
From energy availability to capacity loss, battery technology is a never-ending chicane of jargon, but the key variable is energy density: how much energy can cell makers pack into a limited space? Technicians then have to compromise between how quickly the cells release energy (high discharge rates add-up to high top speeds) and how long the battery will run for (the total range). Double one and you halve the other.
Yet McLaren has achieved the impossible
by upping both. It has increased the number of cells per car, from 165 to 209, pushing the limits on weight, but has also realised a near-doubling of energy density. It is making the sport “quicker and slicker”, McLaren boasts,“eliminating the need for drivers to swap cars during a race.” How has it made such a huge gain?
Inside each battery is a mix of liquid metals, which cell makers endlessly tweak. Lithium and nickel have high energy density but heat-up quickly and can explode or catch fire. Cobalt has a tight molecular structure, so batteries can be recharged repeatedly without performance dropping off a cliff, whilst manganese keeps overall temperatures low.
The chemical composition inside Formula E's batteries is a closely-guarded technical secret, but one possibility is that McLaren is using a nickel-heavy design, with 811 chemistry, using eight parts nickel for every one part cobalt and manganese. 811 formulas are well known, but are thought to be years away from commercial production. An alternate explanation is that McLaren may have added a breakthrough ingredient: aluminium.
Aluminium batteries have high energy density and fast charging times, plus zero flammability. The drawback is poor battery life, but adding graphite can counter the problem, according to scientists at Stanford University. Vanadium batteries could theoretically deliver similar results, but less testing on vanadium has been done.
Do the clues point to Formula E flipping to aluminium? Williams, looking to punch holes in McLaren's system, told governing body the FIA that the new batteries have high levels of 'degradation', meaning they could struggle to keep-up performance race after race. That would be the hallmark of an aluminium battery. McLaren says it can fix the problem.
Either way, aluminium could alter the global battery market, accelerating the shift to electric vehicles. At today's prices it costs $2,287 per tonne, versus $15,235 for nickel and $83,250 for cobalt, making aluminium one-fortieth of the price. It is also lightweight, boosting fuel efficiency, and can be reliably sourced from countries including Canada and Australia, whereas cobalt relies on the Democratic Republic of Congo, one of the world's most chaotic countries, for two-thirds of production.
Motorsport has always been a “test bed” for new technologies that will be commonplace on motorways in two decades time, racing bosses say. Other innovations being pushed by Formula E include battery cooling tubes, an engine disarming device and brakes that double as rechargers, taking energy out of the wheels and putting it back in the battery, gaining an extra lap for every four laps raced. All the while, recharging times are getting quicker: each car can now be charged in under an hour.
But if aluminium is the unknown metal in Formula E's new batteries, it could be the sport's biggest gift to the auto market. “It’s incredible to see the progress made in just four years,” Jean Todt has said. “To double the range of the car and increase the power output is a fantastic achievement.”
Formula E's next race starts in Zurich this afternoon, Sunday 10th June, 18.03 local time (click here for broadcasters)
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Full Spin: Click the battery to watch two laps round Monaco, showing how Formula E has sped-up in its first few seasons. “The speed increase is there for all to see,” say race organisers, who refuse to discuss the new technology behind the gains