Mercedes is not new to the electric semi-truck market but they have a new entry that looks pretty serious. Its the eActros 600 long-haul semi.
Tesla still wins with its 500 mile (800 kilometer) range but this is not bad with a 500 kilometer range. One strange thing is that the article says it has a 4-speed transmission — not something you would expect in an electric vehicle.
See the New Atlas article for more information.