The present disclosure provides a secondary battery, which comprises a cap plate, at least two cells and two connecting pieces. The cap plate is provided with two electrode terminals which are opposite in electrical polarity. Each cell has two tabs which are opposite in electrical polarity. Each connecting piece has: an electrode terminal electrical connecting portion for electrically connecting with the corresponding electrode terminal of the cap plate; a plurality of tab electrical connecting portions for electrically connecting with the corresponding tabs of the cells respectively; and a plurality of fusing portions electrically connecting the corresponding tab electrical connecting portion to the electrode terminal electrical connecting portion, a width of each fusing portion is less than a width of the electrode terminal electrical connecting portion. A configuration of the connecting piece is simple, thereby reducing the cumulative heat of the secondary battery and reducing the temperature rise.