Abstract: A spacer disposed between first and second unit cells has a corrugated portion. The corrugated portion includes first and second protrusions alternating continuously and repeatedly in a vertical direction. The first protrusions protrude from a center in the thickness direction toward the first unit cell to form clearances that function as cooling passages between the first protrusion and the second unit cell. The second protrusions protrude from the center in the thickness direction toward the second unit cell to form clearances that function as cooling passages between the second protrusions and the first unit cell. The spacer includes a straight portion extending in a direction crossing the cooling passages so as to prevent elongation of the corrugated portion in a direction perpendicular to the cooling passages.

Abstract: Provided is a battery pack that can securely prevent liquid, such as water and wash fluid, attached to an outer surface of a packaging case housing a plurality of electric cells from entering an internal space of the packaging case from between a tray and a cover and that also allows easily performing attachment and detachment work of the cover to and from the tray. The packaging case includes an edge cover for covering the whole circumference of a lower flange portion of the tray and an upper flange portion of the cover that abut each other. The edge cover includes a first section facing the lower flange portion, a second section facing the upper flange portion, and a connecting portion for connecting base ends of the first section and the second section. A plurality of female threaded portions are arranged on either the first section or the second section.