An interconnect board assembly (301, 302, 303), comprising: an ICB frame in which cell leads of unidirectional battery cells are receivable such that the unidirectional battery cells having the cell leads at one end are placeable facing each other with the cell leads facing each other; and busbars (321a, 321b, 321c, 322a, 322b, 322c, 323a, 323b, 323c) assembled in the ICB frame and electrically connectable to the cell leads, wherein the ICB frame is a plate type structure having a length and a width, including a cell lead mounting part (A11 ~ A14), a High Voltage (Hv) terminal mounting part (B 11, B12) and a busbar insertion hole (C11 - C13) where the cell leads of the battery cells are placed such that the battery cells are placed facing each other on two sides with respect to a lengthwise direction center line, wherein the cell lead mounting part (A11 ~ A14) is formed at two places along each of first and second sides (311a, 311b) of lengthwise direction of the ICB frame, and includes a first cell lead mounting part and a third cell lead mounting part along the first side and a second cell lead mounting part facing the first cell lead mounting part and a fourth cell lead mounting part facing the third cell lead mounting part along the second side, the Hv terminal mounting part (B11, B12) is formed on each of third and fourth sides (311c, 311d) in a widthwise direction perpendicular to the first and second sides (311a, 311b), and includes a first Hv terminal mounting part on the third side and a second Hv terminal mounting part on the fourth side, and wherein the busbar insertion hole includes a first busbar insertion hole for insertion of the busbar from the third side into the first cell lead mounting part, a second busbar insertion hole for insertion of the busbar from the third side into the second cell lead mounting part, and a through busbar insertion hole formed through the ICB frame parallel to the widthwise direction for insertion of the busbar placed on both the third and fourth cell lead mounting parts (A13, A14). an ICB frame in which cell leads of unidirectional battery cells are receivable such that the unidirectional battery cells having the cell leads at one end are placeable facing each other with the cell leads facing each other; and busbars (321a, 321b, 321c, 322a, 322b, 322c, 323a, 323b, 323c) assembled in the ICB frame and electrically connectable to the cell leads, wherein the ICB frame is a plate type structure having a length and a width, including a cell lead mounting part (A11 ~ A14), a High Voltage (Hv) terminal mounting part (B 11, B12) and a busbar insertion hole (C11 - C13) where the cell leads of the battery cells are placed such that the battery cells are placed facing each other on two sides with respect to a lengthwise direction center line, wherein the cell lead mounting part (A11 ~ A14) is formed at two places along each of first and second sides (311a, 311b) of lengthwise direction of the ICB frame, and includes a first cell lead mounting part and a third cell lead mounting part along the first side and a second cell lead mounting part facing the first cell lead mounting part and a fourth cell lead mounting part facing the third cell lead mounting part along the second side, the Hv terminal mounting part (B11, B12) is formed on each of third and fourth sides (311c, 311d) in a widthwise direction perpendicular to the first and second sides (311a, 311b), and includes a first Hv terminal mounting part on the third side and a second Hv terminal mounting part on the fourth side, and wherein the busbar insertion hole includes a first busbar insertion hole for insertion of the busbar from the third side into the first cell lead mounting part, a second busbar insertion hole for insertion of the busbar from the third side into the second cell lead mounting part, and a through busbar insertion hole formed through the ICB frame parallel to the widthwise direction for insertion of the busbar placed on both the third and fourth cell lead mounting parts (A13, A14).