Disclosed herein is a battery 
cartridge-connecting 
system for battery modules, comprising: 
bus bars, each of which includes a plate-shaped bar body, 
coupling parts, and 
electrical connection parts; a base plate, to which the 
bus bars are easily mounted; and a 
printed circuit board (PCB), which is easily coupled to the 
bus bars and is mounted to the base plate in a compact structure. The present invention also provides a battery module and a medium- or large-sized 
battery system including the battery 
cartridge-connecting 
system. According to the present invention, the battery 
cartridge-connecting 
system easily accomplishes the 
electrical connection and the mechanical 
coupling in the compact-structured battery module or 
battery system. In addition, the battery cartridge-connection system has excellent electrical characteristics, such as electric resistance at the connected parts, after the 
electrical connection is completed, and excellent 
mechanical strength to external impacts or vibrations after the mechanical 
coupling is completed. Furthermore, the battery cartridge-connecting system prevents a risk of an engineer or a user being exposed to the electrical short circuits when the battery module or the 
battery system is manufactured or when the battery module or the battery system is repaired.