to each other thereby accomplishing easy and safe electrical connection between the cartridges application_number US 27396105 A description now a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings it should be noted however that the scope of the present invention is not limited by the illustrated embodiment fig3 is a typical view illustrating the electrical connection of cartridges in a battery pack according to an embodiment of the present invention and fig4 is a perspective view illustrating a battery pack constituted by stacking cartridges one of which is shown in fig1 in the structure shown in fig3 to assist easy understanding the cartridges shown in fig4 are not electrically connected with each other referring to fig3 and 4 the battery pack 300 includes ten cartridges which are connected in series with each other in an alternate 180 degree orientation manner specifically electrode terminals 151 and 161 of a first cartridge 101 and electrode terminals 152 and 162 of a second cartridge 102 are arranged in opposite orientations on the other hand electrode terminals 153 and 163 of a third cartridge 103 and the electrode terminals 151 and 161 of the first cartridge 101 are arranged in the same orientation also electrode terminals 154 and 164 of a fourth cartridge 103 and the electrode terminals 152 and 162 of the second cartridge 102 are arranged in the same orientation such alternate orientations of the electrode terminals are the same for all the cartridges consequently the electrode terminals of the odd numbered.