A battery module 100 includes a plurality of cells 10 arranged in a grid array. The cells 10 arranged in a row direction are connected together in parallel by a first connecting member 20. The cells 10 arranged in a column direction are connected together such that the cells 10 adjacent to each other in the column direction are connected together in series by a second connecting member 30. When an internal short-circuit occurs in any one of the cells 10, the first connecting member 20 connected to the cell 10 in which the internal short-circuit has occurred is melted by Joule heat generated due to a short-circuit current flowing into the cell 10 in which the internal short-circuit has occurred from the other cells 10 in which no internal short-circuit occurs via the first connecting member 20.