A battery module is configured such that n series blocks 20, each having m cells 10 connected in series, are connected in parallel. Adjacent cells 10 are connected in parallel via a first fusible link 30. One end of each of the series block 20 is connected to an input/output terminal 50 via a second fusible link 40. The number m of the cells 10 and the number n of the series blocks satisfy the formulas (1) and (2): m≦½[Vc/Rc·If1−Rf1/Rc+3]  (1) n≧(Vc+If2·Rc)/[Vc−(m−1)If2·Rc]  (2) where Vc and Rc represent an electromotive voltage and an internal resistance of the cell 10, respectively; Rf1 and If1 represent a resistance and a fuse current of the first fusible link 30, respectively; and If2 represents a fuse current of the second fusible link 40.