into the module case 200 through the upper through holes 210 a is easily discharged out of the module case 200 through the through holes 210 b the sliding protrusions 230 are formed at the right and left sides of the through holes 210 b such that the sliding protrusions 230 extend in the longitudinal direction of the module case 200 at the rear of the battery module 100 are located a power connector 420 and a communication connector 410 through which the battery module 100 is electrically connected to an external circuit fig3 is a typical view illustrating the electrical connection structure between the rear connectors and the battery cells in the battery module an anode power cable 422 connected to anode plates of the battery cells is connected to an anode connector of the power connector 420 located at the rear of the module case 200 and a cathode power cable 321 is connected to a cathode connector of the power connector 420 via a switching element such as a field effect transistor fet element for controlling the overcharge overdischarge and overcurrent of the battery cells also a communication port for detection of voltage and communication with another battery module is connected between a main board assembly of the battery module and the communication connector 410 located at the rear of the battery module fig4 is a partially enlarged view illustrating a variable grip according to a preferred embodiment of the present invention the variable grip 300 is mounted to the front of the module case 200 such that one end of the variable grip 300 is hingedly connected to the module case 200 at the other end.