PURPOSE: To reduce the punching dust considerably while to suppress the expansion of the plate thus to lengthen the service life of a cell, by arranging one or plural rows of a plurality of rhomboidal openings having the predetermined angle along the londitudinal direction with predetermined interval in a thin lead alloy plate then stretching said holes in the predetermined direction to form a long continuous meshed substrate.

CONSTITUTION: Rhomboidal openings 8 are punched through a thin lead alloy plate composed of 0.05% of Ca, 0.3% of Sn and the remainder of Pb having the thickness of 0.65mm. Assuming two sides of said rhomboid are (a) and (b) while indicating the longitudinal direction of the long size lead by an arrow α, (a) and (b) are parallel while (b) and (d) are arranged in three rows while holding the angle of θ and each rhomboid is arranged regularly with predetermined interval. Consequently the punching dust is reduced considerably, and the yield of the lead alloy material is improved thereby it is economical. Said advantage is higher as the angle θ decreases. While when making the acute section of the rhomboidal into an arc, the corrosion withstandability at the corner is further improved.