Bianca's Shelmet was revealed during her gym battle against Elesa. Bianca captured it sometime before that battle. It didn't last too long in the battle as Elesa's Zebstrika was a very strong opponent which defeated it quite swiftly. To help it recover from the battle, Iris made it a remedy to restore its health. Bianca's Shelmet was a very timid Pokémon as it was shy during battling as well as when it had to interact with anyone.
Battle against Professor Juniper's Karrablast
Professor Juniper wanted to have a battle with her Karrablast against Bianca's Shelmet to record their data before the evolution. Bianca agreed but the battle didn't turn out as interesting as Cilan hoped it would. Bianca's Shelmet kept hiding in its shell and used Protect to increase its defense. The battle was cut short when one of Professor Juniper's assistants informed her that they were having problems at the base camp.