Battery including insulation piece having drainage groove and electrical device including the same

A battery, comprising:

• a battery cell, comprising a shell and an electrode terminal, wherein the shell comprises a first wall, and the electrode terminal is disposed on the first wall;
• a busbar, electrically connected to the electrode terminal;
• and
• an insulation piece, disposed on one side, facing the electrode terminal, of the busbar and covering at least a part of the first wall,
• wherein the insulation piece includes a first groove recessed along a direction facing away from the first wall such that the first groove is open toward the first wall,
• wherein the insulation piece further includes a second wall facing the first wall, the second wall being adjacent to at least a part of the first groove, and the second wall being inclined toward the first groove from the first wall to form a flow path for an electrolyte solution from the first wall to the first groove.