A battery module comprising: a plurality of battery units arranged in one direction; a plurality of cooling fins (8, 18, 28, 48, 58; 108, 118, 128, 148, 158) between adjacent battery units defining along said direction a central region and a side region (28, 58; 128, 158) of the plurality of cooling fins in the battery module; and a heat sink coupled to ends of the plurality of cooling fins, each cooling fin having a structure in which a pair of sub-cooling fins (3 and 6, 13 and 16, 23 and 26, 43 and 46, 53 and 56; 103 and 106; 113 and 116, 123 and 126, 143 and 146, 153 and 156) are face-to-face coupled to each other, and the plurality of cooling fins having a reducing thickness (T1, T2, T3) along said direction from said central region toward said side region due to a thickness difference of at least one of the sub-cooling fins (13, 23, 46, 56; 113, 123, 146, 156); characterized in that each of the plurality of cooling fins has a '┴' shape, comprises a left sub-cooling fin (3, 13, 23, 43, 53; 103, 113, 123, 143, 153) comprising a metallic bent plate having a '┘' shape and a right sub-cooling fin (6, 16, 26, 46, 56; 106, 116, 126, 146, 156) comprising a metallic bent plate having a '└' shape, and in that for each of the plurality of cooling fins, one of the left sub-cooling fin (13, 23, 43, 53; 113, 123, 143, 153) and right sub-cooling fin (16, 26, 46, 56; 116, 126, 146, 156) which faces said central region has a greater thickness (T11 or T21) than the thickness (T21 or T31) of the other right sub-cooling fin or left sub-cooling fin which faces said side region (28, 58; 128; 158), and wherein the pair of sub-cooling fins (3 and 6, 13 and 16, 23 and 26, 43 and 46, 53 and 56; 103 and 106; 113 and 116, 123 and 126, 143 and 146, 153 and 156) are bonded to each other through a thermal conductive adhesive or a thermal conductive double-sided adhesive film. a plurality of battery units arranged in one direction; a plurality of cooling fins (8, 18, 28, 48, 58; 108, 118, 128, 148, 158) between adjacent battery units defining along said direction a central region and a side region (28, 58; 128, 158) of the plurality of cooling fins in the battery module; and a heat sink coupled to ends of the plurality of cooling fins, each cooling fin having a structure in which a pair of sub-cooling fins (3 and 6, 13 and 16, 23 and 26, 43 and 46, 53 and 56; 103 and 106; 113 and 116, 123 and 126, 143 and 146, 153 and 156) are face-to-face coupled to each other, and the plurality of cooling fins having a reducing thickness (T1, T2, T3) along said direction from said central region toward said side region due to a thickness difference of at least one of the sub-cooling fins (13, 23, 46, 56; 113, 123, 146, 156); characterized in that each of the plurality of cooling fins has a '┴' shape, comprises a left sub-cooling fin (3, 13, 23, 43, 53; 103, 113, 123, 143, 153) comprising a metallic bent plate having a '┘' shape and a right sub-cooling fin (6, 16, 26, 46, 56; 106, 116, 126, 146, 156) comprising a metallic bent plate having a '└' shape, and in that for each of the plurality of cooling fins, one of the left sub-cooling fin (13, 23, 43, 53; 113, 123, 143, 153) and right sub-cooling fin (16, 26, 46, 56; 116, 126, 146, 156) which faces said central region has a greater thickness (T11 or T21) than the thickness (T21 or T31) of the other right sub-cooling fin or left sub-cooling fin which faces said side region (28, 58; 128; 158), and wherein the pair of sub-cooling fins (3 and 6, 13 and 16, 23 and 26, 43 and 46, 53 and 56; 103 and 106; 113 and 116, 123 and 126, 143 and 146, 153 and 156) are bonded to each other through a thermal conductive adhesive or a thermal conductive double-sided adhesive film. <EOS>