Everybody is talking about the e-premium for electric cars. It is supposed to get more e-cars onto the roads. However, according to the influential Academic Advisory Board of the Federal Ministry for Economic Affairs, that will not help protect our environment. Instead, it recommends converting all city buses to electric motors in order to reduce air and noise pollution. But are e-buses really the solution?
Thanks to their electric motors, electric buses, or e-buses for short, are almost silent and emissions-free, but cannot cover the same distances as and are more expensive than buses with petrol or diesel engines. In order to be able to make use for local urban transport viable, there are, therefore, two challenges to be met: range and costs – and these are the challenges that the battery experts at the automotive engineering developer BFFT’s Berlin site set themselves in a unique project:
The BFFT specialists are managing to increase the vehicle’s range by using energy efficient ancillary units (e.g. air conditioning) and an extremely lightweight energy storage unit. This minimizes losses and more energy is retained for the e-bus’ drive system. This is further supported by the intelligent battery management system. During the drive cycle, braking energy is recovered (recuperation) in order to re-charge the battery. In addition to this, an innovative quick charging system, developed in collaboration with partners, tops up the energy at every terminus: a laser-based measurement system, similar to that used for identifying trucks at toll booths, recognizes the approaching vehicle. As soon as the vehicle is parked in the allocated charging position, a pantograph (loading arm) starts charging the vehicle. For this, a large amount of energy needs to be transferred in the shortest possible time. This is why BFFT uses components developed for railroads, which enable high charging capacities of up to 250 kW. As a result, the vehicles are able to stay out on the roads from the morning through to the evening before requiring the next full charge at the depot. Here, the battery is charged overnight using a DC combo plug developed for the automotive sector.
The second challenge to be tackled for regular operation is the cost. That is why BFFT has developed a modular battery system that makes efficient replacement of individual modules (rather than the whole system) possible, e.g. for repair or to make adjustments as required by the customer. This means that the battery system can be customized from the start in order to meet the particular wishes of the vehicle manufacturer or local framework conditions. Even employees who have not been specifically trained to deal with high-voltage equipment can exchange the components. The long service life of five years or 7,000 charging cycles also reduces the running costs and brings savings in fuel and taxes. This means that the purchase price is amortized significantly faster.
The e-bus was presented to the international public at the biggest European trade fair for this sector, Transports Pubic in Paris, June 14-16 2016. From autumn 2016 two 18-meter, tram design VanHool e-buses (Equi.City 18) will be put into service for the transport company Hamburg-Holstein GmbH. That way BFFT, together with its partners, is turning the vision of a fully electric bus for routine operation into a reality – and is making a significant contribution to protecting our climate, even without the buyer’s premium.