Is it a radical break with the past, or the studied creation of a new racing tradition that builds on the classic principles that bring cars and technology together. Either way it is going to result in great demonstrations of mechatronic engineering, vehicle design and serious racing performance. The FIA announced a new class of vehicle racing, the Formula E class. 10 races at tracks around the globe starting in Beijing this fall.
The initial specifications are pretty impressive. 0-62 mph in 3 seconds or less. Top speed will be 150 miles per hour. Audible noise is approximately 70 decibels. And my personal favorite; 800 kilogram total weight including driver of which no more than 200 kg are battery.
F=ma is a three variable system. You can easily manage the tradeoffs if one variable is held constant. Force is the battery system. The amount of energy storage required and the rate at which the power must be delivered is the focus of the “F” term. Considering that the battery is the most expensive part of an electric vehicle, then if we are going to see electric cars become more popular, the easiest way to get there is reduce the vehicle weight. The battery mass, weight and cost, will all follow proportionately.
The second most important variable is the acceleration “a”. This is because the acceleration requirement has an exponential impact on the force requirement. In the Renault Spark a 3 second time from 0-62 mph means an incredible amount of force, that is current, has to be released from the battery system and electric motor or motors, and power electronics all have to be able to withstand the “F” requirement as they convert electrical power into mechanical power.
This requirement in the electric motorcycle world means everything is water cooled. Interestingly, everything in gasoline engine racing is water cooled too. Because at the end of the day, it’s all about the thermal limits of the system. Don’t care what kind of energy is involved, electricity, combustible fuels, atomic energy.
Back to the “a”, if you relax the acceleration requirement to 6 seconds the reduction in force that the battery need to support in much less than half. The exact relationship is based on a somewhat more complex calculation, but the “a” term can reduce peak current loads by 10 times depending on the particular system that is in defined.
The proposed FIA specs translated to a consumer car would be pretty incredible. Consider the specs if it were a small, lightweight 2 seater, with a small trunk like the Lotus Elise. The spec 30kWh battery would give at least 100 miles per charge and with battery pricing falling to $250/kWh in the near future, would cost $7500. With slower acceleration specs the battery pack can be decreased substantially, further reducing the cost and weight.
So regardless of why FIA wants to field electric formula 1 racing, the very first group of cars like the Spark-Renault SRT 01E provides the proof of concept for electric cars.
And we need more of that!