... and Tesla planning to build 4 more gigafactories around the world next year, building electric vechicles whose batteries are mainly nickel. That must impact the supply side in the next few years pushing prices up.
https://electrek.co/2017/05/01/tesla-gigafactories-4-more-year/
https://electrek.co/2016/11/01/breakdown-raw-materials-tesla-batteries-possible-bottleneck/