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Spared the tight regulation that governs most race series, the electric Lola is a showcase for free thinking BATTERY
The Nanophosphate® lithium ion battery has an energy capacity of 30kWh, and where this car differs most from conventional electric vehicles is that the battery is part of the car’s main structure. “People are just throwing batteries in wherever they can fit them on a lot of electric cars at the moment,” says Angus Lyon. “Quite a few have them down their sidepods, which isn’t great from a weight distribution or safety point of view.”
The battery lasts for six or seven minutes at out when you use all 850bhp, but that increases when you ask for less power. Still, it’s not a long time if you want to race it. The car was designed with a fairly small battery, really,” Lyon says. It was designed as a lap-attack car. We wanted to go out and show that the car was faster than rivals with an internal combustion engine. It wasn’t about range, but then again it could race for up to 15 minutes at a very acceptable pace.”
Battery technology is the big limiting factor with any electric car at the moment, but “it’s coming” according to Lyon. What’s more, a battery like your phone uses will have very good ‘energy density’ it will last for hours (unless you have an iPhone5, which will last for minutes). However, a battery powering a racing car will need very high ‘power density’ the rate you can extract power and will therefore, for the moment, sacrifice its length of life.
The two are not easily combined.
Although the power in the Drayson Lola comes from heavily modified laptop batteries, combined to make one large, power-dense unit, bespoke automotive batteries are starting to emerge. The problem is that the manufacturers are quite a conservative bunch when it comes to battery technology,” Lyon says. They just want to make something that works look at the Nissan Leaf or the Chevy Volt… They’re both good cars, but they’re reasonably conservative, they don’t push the boundaries because the last thing they want is a car that fails.
This is where we come in when there’s a technology that’s ready, but not ready to be used on a road car, we can race it. Testing batteries in motor sport is like an accelerated life test because we take them to their limits in terms of state of charge, we push them with temperatures and we want to charge them really quickly, which can damage them.
“A lot of the battery design direction in the short term is about optimising the packaging, in the mid-term it’s optimising the chemistries and in the long term introducing new chemistries.” INVERTERS AND CENTRAL CONTROL SYSTEM
In order to get the electric power to the motors it must first be converted from DC to AC, which is what an inverter does. The battery is just a big DC lump, while the motors are AC,” says Lyon.
“How it works is that we have a centralised control system that sends messages down to each of the liquidcooled Rinehart inverters (there’s one for each motor). It just sends a message saying ‘give me this much torque’. They do the processing, monitoring the temperatures and speeds of the motor and decide how actually to control the DC supply. The central control system acts a bit like an engine management ECU on an Fl car. It does the basics of turning the system on, powering it up and down in a safe manner, monitoring everything
from the voltage to the motors, the temperatures and the chassis for detecting failures.
“It also manages the dynamics: when the driver puts his foot on the throttle, what is he asking for? And what does that really mean in terms of power distribution and power figures?
The inverters are fairly dumb in that all they get is a torque demand and they deliver that demand and give a whole load of information back in terms of their state of health, temperatures and actual torque delivery.” MOTORS
“Almost none of these components come off the shelf, because we’ve worked with suppliers to improve them. The motors were 95kW, but we’ve pushed them up to 160kW,” says Lyon.
“There are four of them in two pairs and each pair drives a rear wheel.There are two basic maps to what we have. One is the basic drive distribution, which in a straight line is 50:50. That gives a car that drives in a normal way. Then there’s the torque vectoring distribution, which actively enhances torque split. Let’s say the driver is negotiating a right-hand bend; it will put more torque to the left wheel to help push the car around.
The dynamics of the car are not as good as they were because the weight distribution has moved back a bit and it is a bit heavier, but using tricks like that can help get the handling back to where it was before.
The other good thing with torque vectoring is that you can compensate for variables such as changing tyre characteristics. You can make a car handle more consistently throughout an entire stint, something that can be changed from the cockpit or done automatically by the car.” The electric drive certainly packs a punch, as Lyon reckons that you get the same acceleration as you would by dumping the clutch with the Judd engine in the back. “It’s the same initial pull off the line, but the power just continues. With an internal combustion engine you lose power every time you
change gear, but this thing just keeps going. When you leave the line you think this is quick’, then at 50mph it’s ‘blimey’ and then at 100mph ‘bloody hell’.”
The two motor pairs each have gears linked to a drop gear on the driveshaff it looks like a differential externally, but there’s no link between the wheels. The drive goes into the centre, where the drop gear is located, and then comes out via the driveshaff to the wheels. MOVEABLE AERO
“Currently there are three moveable aerodynamic surfaces on the car: the biplanes at the front, the gurney at the bottom of the rear wing, which is similar to DRS on an Fl car, and the upper flap on the rear wing,” says Lyon. “At the moment it’s the driver that activates these with paddles on the
steering wheel. We could control it automatically, but we decided that it would be better not to add the extra layer of complexity. Losing 30 per cent of your downforce and drag at the wrong time isn’t good so we’ve concentrated on getting the drivetrain right.”
THE TECHNOLOGY ON THE B12/69 EV is staggering, and as well as everything mentioned above it uses wireless charging which can be done in 15 minutes, energy-recovering dampers which power the rear lights, and brake energy regeneration.
You could argue that the car isn’t competing on a level playing field with the standard LMP1 machines because of the moveable aero and torque vectoring, but that’s not the point of the programme. The car exists to showcase what can be done with electric power and drive those technologies forward. It did the former during the Goodwood Festival of Speed and the latter will be proven in the next few years. None of us wants to see motor racing become all-electric, and neither does the team at Drayson Racing. What this car offers, though, is a partial glimpse of the future. al