To address the challenge with battery driven vehicles that it takes long time to recharge the batteries, Swedish-Swiss based technology firm ABB has come up with a flash charging technology that it says will charge an electric bus as quickly as car tank fills with petrol. Last week, two articulated electric buses, the first of their kind in the world, went into service on bus line 23 in Geneva.
ABB said that it takes less than 1 second to connect the bus to the charging point on an overhead high-power charging contact when it pulls into selected stops and tops up its batteries while passengers embark and disembark. Referred to as TOSA (Trolleybus Optimisation Système Alimentation), the buses receive a quick, flash-charge at selected passenger stops, in addition to charging buses for four to five minutes at the end of their routes. Several seconds are saved at each flash-charging stop, so it takes less time at the end terminal to return the battery to its 100 percent state – and keeps the buses aligned with the timetable.
In a blogpost Bruce Warner of ABB wrote that the uptake of electric vehicles on roads signals a shift towards a low-carbon, less polluting environment. In some cities, there is now electric buses powered entirely by batteries. One of the challenges with battery driven vehicles today is the time that it takes to recharge the batteries.
“Buses present a particular challenge as operators want the vehicles on the road transporting passengers, not waiting at charging stations. Until recently, one option was for operators to use additional electric buses on a bus line – but this inevitably increases the cost of the electric bus fleet. Today, ABB has a flash charging technology solution that can quickly charge a battery in the same time it takes for passengers to get on and off the bus – around 20 seconds,” wrote Warner.
According to ABB, different buses will have different routes that will require varying amounts of energy. Factors will depend on the length and topography of the route, the size of the bus, heating or cooling in the bus and the number of passengers. “The flash charging technology is able to adapt to this by simply varying the number of flash-charging stations–offering a uniform charging system for a city's entire fleet,” said ABB.
Warner explained that the TOSA buses have a simple interface between the bus and wayside which does not require any dialogue between the battery management system and the wayside feeding station – something which takes some time to establish. Another time-saving feature is that the connection arm on the roof automatically aligns and connects in less than a second, making it the world's fastest flash-charging connection technology.
“Through optimal energy management, the system can save as much as 1,000 tons of carbon dioxide on a line covering 600,000 kilometers per year,” claimed ABB.
