Abstract: The present invention provides a battery module system including a plurality of battery modules in a series electrical connection through a specified sequence, each battery module having a male connector and a female connector, the female connector of each battery module in electrical engagement into the male connector of an adjacent battery module, wherein the male connector and female connector are positioned along the sidewall of each battery module and have insulating structures that protect handlers of the battery modules from high voltage electrocution. The present invention also provides a battery module system in which the male and female connectors are attached to a top surface of each battery module.