At the heart of an electric vehicle is the battery. With the eCitaro, Mercedes-Benz is already presenting the near future of battery technology – good prospects for the future of electromobility.

The complicated term is lithium nickel manganese cobalt oxide cells, or NMC for short among experts. Which explains why everyone prefers to simply talk about lithium-ion batteries. Yet just as no two city buses are the same, no two lithium-ion batteries are identical. The composition of those in the new eCitaro is selected so that they are suitable for high charging currents for high-power charging and, thanks to their energy density, are also good for long ranges.

Every single battery cell has a capacity of 37 Ah. The prismatic cells are roughly the shape and size of a paperback. Twelve battery cells make up one cell module. 15 cell modules plus a control unit for monitoring and balancing the charge between cells make up one battery module. The number of battery modules is variable. The eCitaro starts with a total capacity of 292 kWh maximum. For maximum performance, charging capability and lifespan, the batteries in the eCitaro are treated carefully. A liquid cooling system keeps them at their ideal temperature of around 25 degrees Celsius.

Thus equipped, the eCitaro can drive up to 280 kilometres without recharging in ideal conditions. In summer with air conditioning running, this is reduced to 170 kilometres according to SORT 2. With this system-relevant range, it already covers around a third of all routes typically served by transport companies.

The battery starter pack for the eCitaro is just the beginning, as battery technology is developing rapidly. The eCitaro is prepared: the next generation of batteries is expected sometime next year. Also NMC batteries, but with around 50 Ah per cell. That means a total capacity of around 396 kWh with twelve battery packs, with the range increasing accordingly. The space and connections are identical, and the higher weight is considered in the vehicle concept – the eCitaro will remain, its “electricity tank” will grow. Customers can even undergo bus tuning and replace the first batteries for the new, more efficient powerful generation after a few years.

The step towards a second technology path is expected at the same time: as an alternative to NMC batteries, the eCitaro will have solid-state batteries. Here the electrolyte is in a solid form. The advantage of solid-state batteries: they are particularly long-lasting, have a very high energy density and do not require cooling either. For the eCitaro this means around 400 kWh total capacity, 280 kilometres system-relevant range, route coverage of 70 per cent. Solid-state batteries are not suitable for high-power charging, however, so quick intermediate charging en route is not possible. This means a choice of two battery technologies, with every transport company getting the right eCitaro for its operating strategy

Shortly thereafter, the eCitaro will finally move to the fast lane: we will then see the eCitaro with a fuel cell as a range extender. It will be designed so that the eCitaro will achieve a system-relevant range of 400 kilometres without recharging according to SORT 2. It will thus cover practically 100 per cent of city bus routes and turn into an all-rounder like the eCitaro with a combustion engine. The timetable is set. The journey into the electric future is beginning.