The battery in a Formula One car provides a vital performance boost – but only if it can cope with the extreme conditions of a race.
The 2009 Belgian Formula One Grand Prix was decided in the fifth lap. The hilly, winding circuit had already seen four drivers retire following a collision on the first lap. The safety car came out, slowing drivers down while the track was cleared.
When the safety car went in, on lap five, Giancarlo Fisichella was first in his Force India Mercedes, with Kimi Raikkonen’s Ferrari close behind. Raikkonen positioned himself to overtake and – at the touch of a button – zoomed past Fisichella and into first place. It was a lead he would not relinquish.
Ferrari was one of a handful of teams that season deploying the new kinetic energy recovery system (KERS), which provided a short-term burst of speed, and Raikkonen had used it perfectly. It was the first time the new system had determined the race winner.
Fisichella was not impressed. “I was quicker than Kimi," he told reporters. "He passed me because of the KERS. I'm a little bit frustrated about that."
KERS came about as a way to address two problems that Formula One had in the mid-2000s: firstly, a lack of overtaking, which was a turn-off for fans; and secondly, criticism that the sport was environmentally unfriendly.
It also meant Formula One cars had a battery for the first time. Unlike a road car, a Formula One car does not start its engine with the help of a battery: instead it requires an external starter motor and careful monitoring of the engine as it roars into life. The KERS battery stored kinetic energy, such as that generated during braking, and made it available at key points during a lap to enhance the car’s speed.
In 2014, KERS was replaced with ERS, which recovers heat energy as well as kinetic energy, giving the driver an extra 160 bhp* for around 30 seconds per lap. The boost can aid overtaking, as it did for Raikkonen.
The environmental benefit is that ERS helps the power unit to run more efficiently, using around 35 percent less fuel.
When the system was introduced, Saft was approached by several teams (such is the hyper-secret world of F1 that we cannot name them). They wanted our expertise in maintaining battery performance under extreme conditions.
The battery must be compact and light because space and weight are at a premium in an F1 car, but most importantly it has to operate at high temperatures with total reliability. Cycling power in and out of a battery generates heat, but cooling systems take up space and add weight, so the more heat the battery can handle without cooling, the better.
The battery we developed grew out of our defense work on the Lockheed Martin F-35 Joint Strike Fighter. However, the long lead times and cautious nature of work in the defense field were anathema in the aggressive world of F1, where technology changes year-on-year.
F1 cars alter radically between seasons and significant changes are made – not just between races, but between days of a race weekend. With vast amounts of equipment and technology in the car, the race team is constantly seeking the combination that will give them the greatest advantage. A 100th of a second saved in a tire change or the tiniest shift in brake balance during a lap can mean the difference between first and second place.
That complex strategy now extends to the battery. Regulations specify limits, such as battery weight and how many different battery systems a team can use each year. Currently a team will face penalties if they use more than four batteries per season, however that number will soon be cut to two.
The new rules present a challenge, both for teams – who will have to adjust their strategy for getting the most out of the available batteries – and for manufacturers such as Saft, tasked with enhancing the durability to conform with the new regulations while maximizing performance in a similar or smaller package.
Famously, technology developed for F1 often helps manufacturers to make better road cars. Sequential gearboxes, active suspension and multi-function steering wheels all have their origins in F1. ERS is no exception; manufacturers including Volvo and Mazda have begun using the system, not only to provide extra power for overtaking but also to help engines run more efficiently.
At Saft, too, our F1 work has fed back into other areas of the business, both in terms of technological advances and the shift of mindset that comes from working on continuous, annual improvement instead of long-term, multi-year projects.
When Kimi Raikkonen hit that button in 2009, he gave a boost to more than just his car.
* bhp: brake horsepower is the amount of power generated by an engine without taking into consideration any of the various auxiliary components that may slow down the actual speed of the engine.