A battery pack may include a tray, a cover, a connection member connecting a peripheral portion of the tray to a peripheral portion of the cover with a clearance provided therebetween, and a sealant filling the clearance. The connection member may include a spacer disposed in a range between the peripheral portion of the tray and the peripheral portion of the cover. The spacer may include first to third portions respectively having first to third cross-sectional areas. The second cross-sectional area may be smaller than the first and third cross-sectional areas. The first portion may be disposed at a position that is in contact with the peripheral portion of the tray. The third portion may be disposed at a position that is in contact with the peripheral portion of the cover. The second portion may be disposed between the first portion and the third portion.