Agile,
A couple years back AW (briefly) flew their Project Zero tilt rotor demonstrator aircraft. It was an all electric propulsion system and was basically a test bed for various technologies they were developing, such as electric propulsion motors/controls, electromechanical IBC actuation, etc. The aircraft was unmanned and of limited scale, but to me the most impressive aspects of the project were that it was funded internally and had a very short (6 month) design/build cycle. Would be great to see more of this in the aerospace industry.
Here's a
2013 video with an interview of the project engineering lead. At 2:15 of the video he talks about the problems with energy density of current battery systems.
Here's a
US patent application published in 2013 covering the concept that is worth a read if you're interested in electric rotorcraft propulsion systems.