Battery pack

A battery pack in which a plurality of power-generating elements are arrayed, with each element comprising a rechargeable single battery, wherein

• the single battery comprises a casing and an electrode body housed in the casing,
• the electrode body is a wound electrode body in which a positive electrode sheet, a negative electrode sheet and a separator sheet placed between the positive and negative electrodes are wound together,
• in the wound electrode body, the outermost circumferential portion of the negative electrode is outside the outermost circumferential portion of the positive electrode,
• the power-generating element further comprises a protection plate placed along the outer surface of the casing of the single battery,
• the protection plate has a metal layer and an insulating layer,
• the metal layer has a first surface located on the single battery side and a second surface located opposite from the first surface,
• the insulating layer is placed on the second surface side of the metal layer, and
• the metal layer is electrically connected to the positive electrode and the metal layer is thereby given with a positive potential.