A battery cell including an electrode assembly, an electrolytic solution and a cell case, comprising: an insulator assembly with electrical insulation is attached to an outer side of at least one of both surfaces of the electrode assembly in a lamination direction of electrodes, and characterized in that the insulator assembly has a single insulator or a structure in which two or more insulators are laminated, and the insulator has a structure including an insulating main body and a plurality of fell-off patterns formed on the insulating main body, when the needle-shaped conductor passes through the fell-off pattern, the fell-off pattern is fallen from the insulating main body and pass through the electrode assembly together with the needle-shaped conductor by the needle-shaped end part of the needle-shaped conductor inserted into the insulator assembly, wherein a total planar area of the fell-off pattern is in a range of 7 to 200 mm 2 so that the fell-off pattern determines a planar shape and area of a through-hole formed in the electrode assembly, the fell-off pattern includes: a fell-off part made of metal, high-strength plastic or ceramic so as to have a tensile strength in a range of about 1 to 10 kg/cm 2; and a needle-shaped conductor guiding part having a planar size of 50 to 80% of a planar size of the fell-off part in the vicinity of a center of the fell-off part, and further including an insulating film which is stretchable along the needle-shaped end part of the needle-shaped conductor, and wherein when the needle-shaped conductor guiding part is fixed to the needle-shaped end part of the needle-shaped conductor, the fell-off part passes through the electrode assembly in a penetrating direction along the needle-shaped conductor in a state of being fallen from the insulating main body. an insulator assembly with electrical insulation is attached to an outer side of at least one of both surfaces of the electrode assembly in a lamination direction of electrodes, and characterized in that the insulator assembly has a single insulator or a structure in which two or more insulators are laminated, and the insulator has a structure including an insulating main body and a plurality of fell-off patterns formed on the insulating main body, when the needle-shaped conductor passes through the fell-off pattern, the fell-off pattern is fallen from the insulating main body and pass through the electrode assembly together with the needle-shaped conductor by the needle-shaped end part of the needle-shaped conductor inserted into the insulator assembly, wherein a total planar area of the fell-off pattern is in a range of 7 to 200 mm 2 so that the fell-off pattern determines a planar shape and area of a through-hole formed in the electrode assembly, the fell-off pattern includes: a fell-off part made of metal, high-strength plastic or ceramic so as to have a tensile strength in a range of about 1 to 10 kg/cm 2; and a needle-shaped conductor guiding part having a planar size of 50 to 80% of a planar size of the fell-off part in the vicinity of a center of the fell-off part, and further including an insulating film which is stretchable along the needle-shaped end part of the needle-shaped conductor, and wherein when the needle-shaped conductor guiding part is fixed to the needle-shaped end part of the needle-shaped conductor, the fell-off part passes through the electrode assembly in a penetrating direction along the needle-shaped conductor in a state of being fallen from the insulating main body. a fell-off part made of metal, high-strength plastic or ceramic so as to have a tensile strength in a range of about 1 to 10 kg/cm 2; and a needle-shaped conductor guiding part having a planar size of 50 to 80% of a planar size of the fell-off part in the vicinity of a center of the fell-off part, and further including an insulating film which is stretchable along the needle-shaped end part of the needle-shaped conductor, and wherein when the needle-shaped conductor guiding part is fixed to the needle-shaped end part of the needle-shaped conductor, the fell-off part passes through the electrode assembly in a penetrating direction along the needle-shaped conductor in a state of being fallen from the insulating main body.