The winner of TechCrunch Disrupt 2017 Startup Battlefield is Pi. They developed a device that allows smartphones and other devices to charge wirelessly . Amazingly, they were able to demonstrate this on stage in front of a live audience. In comparison, in the previous week, Apple annouced their wireless charging pad, Mophie, which is clearly an inferior product. Along with the bragging rights, Pi received a $50,000 cash prize.