Assembled storage battery unit of the collective type

An assembled storage battery unit composed of a plurality of storage batteries assembled as a unit, the storage batteries each including positive and negative electrodes layered through a separator and contained in a bottomed battery casing storing therein an amount of electrolyte and a closure plate welded to an upper opening end of the battery casing to seal the interior of the battery casing in a liquid tight manner,

• wherein the battery casings each are integrally formed with plural pairs of vertical ribs spaced in parallel at one side wall thereof faced to the corresponding side wall of the battery casing adjacent thereto, the vertical ribs each having a flat surface faced to the corresponding side wall of the battery casing adjacent thereto and side surfaces perpendicular to said corresponding side wall, wherein each pair of vertical ribs of the respective battery casings are engaged at their side surfaces with the corresponding pair of vertical ribs of the battery casing adjacent thereto to retain the battery casings in position and to form a plurality of vertical ventilation spaces.

An assembly of plural battery cell casings, each battery cell casing having opposed parallel side walls with protruding vertical ribs each having an outer flat surface and two parallel side surfaces, the vertical ribs on one side wall being offset from those on the other side wall such that the vertical ribs of stacked adjacent cell casings are coupled in pairs and their respective side surfaces are interlocked with each other.