BMW vs Winter: how BMW winter-proofed the i3

Published: 21 January 2013

It’s -30degC outside. The i3 – BMW’s first fully electric production vehicle – faces the bitter Scandinavian winter, and while the moose are smart enough to remain asleep, the early risers in the engineering team are in the thick of it with a fleet of camouflaged i3s and support crew in tow.

Think about a car made by a German company, and then the cold winters that its customers are subjected to. The i3 has to survive not only the scepticism of being ‘born electric’, as its marketing cries, but also real-world practicalities where no amount of marketing will save it.

So how does the i3 pull it off? Cleverly, the car’s air-con coolant is used to regulate the battery pack’s temperature. While it can help the battery survive a tropical summer, this fluid can also be warmed using a heat exchanger to battle the cold. It runs around channels or chambers within an aluminium-alloy case that protects the battery pack from whatever atmosphere is trying to get in. It’s not that far removed from a conventional engine’s water jacket, but is a little more sophisticated.

>> Click here for CAR's review of the all-electric BMW i3

Using this set-up, the i3 suffers no reduction whatsoever to its maximum 124-mile range or to its performance on account of this morning’s bitter sub-zero conditions. ‘It’s more effective because it’s directly cooled,’ says the i project’s Franz-Xavier Biermeier. ‘In some hybrids, there is an outside cooling arrangement, with an outboard connection with the thermal system – but there’s an interface between them. We wanted to go directly to control the temperature. We didn’t want to use energy to heat or cool it.’

In theory, this should make an English winter seem like an also-ran; the i3 shouldn’t even flinch. Even in extreme, sub-zero climes, there’s no drop in the electric motor’s full 184lb ft of torque, available from a single rpm. While wannabes go on about power, it’s torque that determines a car’s drivability, so this is a crucial point.

Also playing its part are those beautifully finished 19in forged alloy wheels wrapped in super-skinny rubber. They not only improve the i3’s range and aerodynamics, but the smaller contact patch also means that the i3 is less prone to aquaplaning in treacherously wet conditions, as water is dispersed much faster than on the wider boots fitted to high-performance machines.

>> Click here for CAR's review of the BMW i3 Range Extender

The i3 has some other tricks that, frankly, probably weren’t even thought of as winning the war on winter. Those plastic panels, for instance, won’t rust, nor will the carbonfibre passenger cell or aluminium chassis. They’re designed for weight, range and everyday drivability, but are part of the i3’s cache against the harshest elements.

And, in case you’re wondering, there are heated seats – yet the iDrive system will tell you just how much they’re taking out of the i3’s range, so you’ll know when you can use them. Or put off your trip and sit inside in the warmth instead – as no doubt BMW’s engineers wanted to in the Arctic conditions while finding all this out…

Comments