PURPOSE: To enhance the collecting performance of a lattice structure by successively shifting the central position of measures aligned in the vertical direction of an expanded lattice structure and providing a lug on the upper edge of the lattice and on the shifted side from the center line of the lattice structure.

CONSTITUTION: Provided that a lug 3 of the expanded lattice structure 1' of a storage battery is positioned in the right hand from the center line B, and the line A which connects the middle point 2 of the measures in a net area 4 is arranged to be shifted rightward as the line is followed downward from the upper side, while the shifting angle θ of the line A is selected on the basis of the position of lug B. Therefore the nodes 5' in the net area are unsymetrically arranged in lateral direction and ribs on the right upper position toward the left lower position are substantially aligned in a straight line. Then the conductivity in the arrow C' direction is better than that in arrow D' direction and also can be better than that in both directions when the lattice is in a sysmetical configuration. Accordingly the collecting performance to connect the net area to the lug may be improved.