can be individually measured by means of an external measurement device not shown the outer peripheral portions of the upper lower plates 10 sandwiching the entire arrangement of the unit batteries 1 is covered by e g a heat shrinkable shrink tube 22 however the outside of the portion of the connector substrate 17 is not covered by the shrink tube 22 further a plurality of sponge pads 23 are adhered to the outside of the shrink tube 22 so as to protect the battery pack from a mechanical impact applied at the time when the battery pack is inserted into a device an assembly procedure of the battery pack according to the embodiment will next be described with reference to fig9 to 12 first as shown in fig9 one of the upper lower plate 10 is set such that the projections 11 face upward on the upper lower plate 10 the unit batteries 1 of the first row from the bottom are arranged such that the main surfaces 3 thereof face upward the side surfaces 13 of the adjacent unit batteries 1 are opposed to each other and the terminal surfaces 4 of the unit batteries 1 are positioned on a same plane the corner portions of each unit battery 1 are retained by the projections 11 then as shown in fig1 a lower spacer 6 is disposed on the unit batteries 1 of the first row from the bottom further.