Provided is a busbar coupling device. The busbar coupling device includes: a plate including a first side and a second side disposed opposite to each other; a first end wall part protruding and extending in a direction that the first side faces at a first end part in a length direction of the plate; a first protrusion part disposed at the plate, spaced from the first end wall part, and protruding in the direction that the first side faces; a second end wall part protruding and extending from a second end part disposed opposite to the first end part to a direction that the second side faces in the length direction of the plate; and a second protrusion part disposed at the plate, spaced from the first end wall part, and protruding in the direction that the first side faces.