Battery, battery pack and vehicle

The utility model provides a battery, battery pack and vehicle relates to battery technical field, including battery lower shell, stack core group and battery upper cover, stack core group is provided between battery lower shell and battery upper cover, stack core group includes a plurality of stack core that sets up horizontally, the long side of adjacent stack core is electrically connected. According to the battery provided by the utility model, the tabs of the stacked cores are arranged on the long edges, and the stacked core group is welded through the tabs on the long edges, so that on one hand, the tabs are subjected to full-area butt welding, the current path can be increased, and on the other hand, the long edges are welded, an ion path in the battery core can reach the positive (negative) electrode as long as passing through the short edges, the ion path is shortened, and the internal resistance of the battery is reduced; therefore, heat productivity and electric quantity loss are reduced, heat mana