CES was a hotbed of car announcements this year, but luckily some surprises have been saved for the North American International Auto Show in Detroit. Take Audi's h-tron quattro, a hydrogen-powered concept car with a Tesla-beating range of 372 miles. It has three fuel tanks hidden beneath the passenger or luggage compartments which can be replenished in just four minutes. The fuel cell has an output of up to 110 kW, supported by a lithium-ion battery which supplies a further 100 kW for short, temporary bursts of acceleration. While you're driving, this secondary power source then slowly recharges every time you tap the brake.