Spray the 6-quart crockpot with cooking spray.
Mix the flour, cocoa powder, baking powder, sugar, and salt in a bowl. Set it to the side.
Using a different mixing bowl, combine the oil, vanilla, and milk. Once mixed, pour the wet mixture into the dry mixture that is waiting in the other bowl. Stir until just combined. Carefully fold in the chocolate chips.
Add the cake batter into the crockpot. Use a spatula to smooth out the top of the batter.
Put a clean towel over the crockpot opening and then put the crockpot lid on top. (This helps stop extra moisture from building up.)
Cook for 1.5 hours on high. Spoon out and enjoy.