A battery pack includes a battery stack having a plurality of prismatic batteries being stacked. The battery pack further includes a cooling plate extending in a stack direction of the prismatic batteries in the battery stack. The cooling plate includes a plurality of coolant passages and a plurality of grooves. The coolant passages extend in a perpendicular direction substantially perpendicular to the stack direction of the prismatic batteries, and allow a coolant to flow in the coolant passages. The grooves constitute heat conduction inhibitors configured to inhibit heat conduction in the stack direction of the prismatic batteries.