Daimler is investing heavily in going electric with its heavy vehicles. We have been mainly reporting on their trucks, but now the German automaker’s Daimler Bus division is also going electric with the Mercedes‑Benz eCitaro electric bus.

They unveiled the new vehicle today.

The company says that the Citaro is “the world’s best-selling city bus with more than 50,000 units sold.”

Now it is getting an all-electric version and Mercedes‑Benz did more than just convert the diesel version to battery-electric.

They did several different upgrades to the vehicle beyond the electric powertrain:

“The roof-mounted equipment of the eCitaro is hidden behind an elegant roof-edge ridge. It is made of a multi-piece extruded aluminium profile. The glossy black lower segment extends the generous glazing of the city bus. The upper segment is painted in the vehicle colour, transitions smoothly into the A0‑pillar at the front and into the corner post at the rear, and visually frames the side. These optical tricks lend the eCitaro perfect proportions and make it seem light.”

Here are a few images of the new electric bus unveiled today:

As for the powertrain, it features electric motors on two axles. The battery system is modular and split between a pack at the back on the floor of the bus and another pack on the roof at the front of the bus.

Daimler describes the battery system:

“Lithium-ion batteries with a total capacity of up to about 243 kWh provide the power. They are modular in design: the batteries are split between up to ten modules, each supplying around 25 kWh. As well as two battery modules on the vehicle roof, the standard equipment includes four modules in the rear of the bus. In the eCitaro, these are taking the place of today’s powertrain combination of combustion engine and transmission. Depending upon customer requirements, another two or four battery modules are mounted on the roof of the eCitaro.”

Here’s a visualization of the eCitaro’s powertrain:

The bus maker is talking about a range of “150 kilometres in the summer” and “up to 250 km in ideal conditions.” That’s 93 to 155 miles.

Thermal management, both for the batteries and for the inside of the bus, is responsible for the big difference.

Daimler talks about the thermal management system:

“It is one of the outstanding features of the eCitaro and has been honed and refined in every detail: Compared with the current Citaro with combustion engine, the energy requirement for heating, ventilation and climate control has fallen by about 40 percent. This exceptional energy efficiency provides the basis for the eCitaro’s practical operating range even under unfavourable conditions. This is accomplished with the use of innovative components that only reached market readiness in concert with the eCitaro.”

As for charging, it will first go through a plug-in system with a Combo-2-plug above the front wheel arch on the right-hand side of the vehicle:

Daimler didn’t confirm the charge rate, but it did mention that it eventually also release a charging system on the roof, which has become standard in many electric buses on the market.

They plan to bring the vehicle to production by the end of the year and say that the first customers are already lined up.

The transit company for the Rhine-Neckar metropolitan region will be the first to take delivery of the eCitaro.

Interestingly, Mercedes-Benz says that it is also working on solid-state batteries to replace the batteries inside the eCitaro in the next few years:

“In parallel to this development, another step is already preordained during that same period, the optional use of future lithium-polymer batteries. They also belong to the class of lithium-ion batteries, but here the usually liquid electrolyte is in a solid state, which is why they are also referred to as solid-state batteries. Solid-state batteries are characterised by an especially long service life and high energy density. With a rated battery capacity of about 400 kWh in the solo bus and even more in the articulated bus, the eCitaro will then meet about 70 percent of all requirements without opportunity charging.”

The announcement also has interesting implications for Daimler’s future electric vehicles like trucks and passenger cars.

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