The utility model discloses a battery case and
monomer battery, this battery case includes the lower casing for accommodating electric core and the sealing element for sealing
liquid injection hole, and the lower casing and sealing element are all fixedly connected to the upper casing, and the upper casing is rectangular board, and is equipped with
liquid injection hole on one corner, wherein, the
radius of
liquid injection hole is recorded as R, and the distance of the center point of the circle of liquid injection hole to the nearest side edge of the upper casing is recorded as L1, and 0.1mm<=L1-R<=2mm. A battery case and
monomer battery, the structure and position of setting liquid injection hole make that the battery case can keep the strength of having, and can effectively guarantee the sealing of liquid injection hole, simplify the manufacturing process simultaneously, effectively guarantee the safety of battery, improve the service life of battery.