BATTERY CELL, ELECTROLYTE INJECTION APPARATUS FOR BATTERY CELL, AND ELECTROLYTE INJECTION METHOD USING THE SAME

A battery cell includes a case, accommodating an electrode assembly therein, and a connection unit formed to have a tube shape and having one end bonded to an external surface of the case. The case includes a projection formed to protrude outwardly, and the projection is disposed in an internal surface of the connection unit.