Middle or large-sized battery module of improved safety

A battery module including a plurality of battery cells or unit modules, the battery module being configured to have a connection structure in which measured voltage and/or temperature signals of the battery cells or the unit modules are transmitted and received by a wire type connection member, wherein at least one end of the connection member is connected to a connection counterpart in a male and female engagement type mechanical coupling manner, the connection member has a downwardly bent region (a downwardly bent portion) formed at a region adjacent to a connection part such that the downwardly bent portion is bent downward to a height lower than the connection part for preventing moisture condensed on the connection member from being introduced to the connection part due to gravity, wherein a lower end of the downwardly bent portion is located at a height 0.5 to 10 cm lower than the connection part, and the downwardly bent portion is configured in a structure in which a first vertical bent point, a horizontal bent point, and a second vertical bent point are continuously disposed.