A battery cell assembly, comprising: a plurality of cylindrical cell blocks, each including a plurality of cylindrical cells; a block cover configured to cover an upper side of the plurality of cylindrical cell blocks and electrically connect the plurality of cylindrical cell blocks; a cooling plate located opposite to the block cover and disposed at a lower side of the plurality of cylindrical cell blocks; and a heat transfer member disposed between the cooling plate and the plurality of cylindrical cell blocks and having a plurality of thermal interface materials corresponding to bottom portions of the plurality of cylindrical cells, wherein the outer surfaces of the plurality of cylindrical cell blocks have a shape corresponding to the outer surface of a facing neighboring cylindrical cell block such that neighboring cell blocks are coupled with each other in a block type characterized in that each of the plurality of cylindrical cell blocks includes: the plurality of cylindrical cells; a bottom cover configured to accommodate the bottom portions of the plurality of cylindrical cells; a top cover coupled to the bottom cover and configured to cover top portions of the plurality of cylindrical cells; a pair of bus bar members (140, 150) provided at an upper side of the top cover to electrically connect the plurality of cylindrical cells; and an insulation member provided between the pair of bus bar members (140, 150). a plurality of cylindrical cell blocks, each including a plurality of cylindrical cells; a block cover configured to cover an upper side of the plurality of cylindrical cell blocks and electrically connect the plurality of cylindrical cell blocks; a cooling plate located opposite to the block cover and disposed at a lower side of the plurality of cylindrical cell blocks; and a heat transfer member disposed between the cooling plate and the plurality of cylindrical cell blocks and having a plurality of thermal interface materials corresponding to bottom portions of the plurality of cylindrical cells, wherein the outer surfaces of the plurality of cylindrical cell blocks have a shape corresponding to the outer surface of a facing neighboring cylindrical cell block such that neighboring cell blocks are coupled with each other in a block type characterized in that each of the plurality of cylindrical cell blocks includes: the plurality of cylindrical cells; a bottom cover configured to accommodate the bottom portions of the plurality of cylindrical cells; a top cover coupled to the bottom cover and configured to cover top portions of the plurality of cylindrical cells; a pair of bus bar members (140, 150) provided at an upper side of the top cover to electrically connect the plurality of cylindrical cells; and an insulation member provided between the pair of bus bar members (140, 150). the plurality of cylindrical cells; a bottom cover configured to accommodate the bottom portions of the plurality of cylindrical cells; a top cover coupled to the bottom cover and configured to cover top portions of the plurality of cylindrical cells; a pair of bus bar members (140, 150) provided at an upper side of the top cover to electrically connect the plurality of cylindrical cells; and an insulation member provided between the pair of bus bar members (140, 150).