Disclosed herein is a middle- or large-sized battery module including a plurality of battery cells or unit modules, the middle- or large-sized 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.