Battery and manufacturing method thereof

A battery disclosed herein includes an exterior body, a sealing plate sealing an opening of the exterior body, electrode bodies each including a first electrode, an electrode tab group electrically connected to the first electrodes, a terminal attached to the sealing plate and electrically connected to the electrode tab group, a collecting unit electrically connecting the electrode tab rid the terminal, and an insulating member insulating the sealing plate and the collecting unit from each other. The insulating member includes a base portion disposed between the sealing plate and the collecting unit, and protrusion portions protruding, from the sealing plate toward the sides of the electrode bodies.