In the Peyrussoa storage battery (France) the lead support is composed of a central rod, and a number of longitudinal and radial strips, which are placed in a porous cup. The spaces between the strips are then filled with peroxide of lead and other material capable of producing the same by oxidation, which is mixed with a little acidulated water. Other forms may be substituted for the radial strips. The porous cup is placed in a second vessel of glass, containing the electrode of the negative pole.
In the storage battery of _Anthony Eeeken-saun (London) the active material is com pletely formed in advance of its application, and is so held in place that the expansion of the plate has no effect on the adhesive property of the active material. Small cylinders of peroxide of lead are prepared, and placed at short dis tances from each other in regular lines upon the lower half of the corrugated mold. The two halves being fitted to gether, the molten metal is poured in. forming a composite plate. As shown in Fig. 10. these cylinders are exposed for a large part of their surface to the direct action of the elec trolyte, being held only at the top. But the inclosing metal is sufficient to permit the plate to be bent over into a com plete circle, without causing the small cylinders to fall out. The plates are designed specially for street car and similar work, where rough treatment is unavoidable.
The Gibson storage battery (New York) has the peroxide of lead introduced in capsules which are perforated, to allow the air to pass out when they are being filled, and also to permit the entrance of the electrolyte when the plate is im mersed. The capsules when inserted in the holes of the plate fit loosely, and project beyond the surface. The plate is then rolled, and the pressure " upsets " the capsules and compresses them against the adjacent metal. A recent form of this battery has the plates arranged horizontally instead of vertically, as is usually the case 11). The plates are strung on bolts, and have pieces between them to keep the plates apart and prevent short circuiting.
Waddell and Enlz (New York) have made nurerous experiments for adapting copper oxide for use in the storage battery. They employ for this purpose a tube of woven copper wire, as shown in Fig. 12. To avoid the lack of coherence in pure copper oxide, Messrs. Eels and Phillips have
modified the composition by combining with the oxide of copper a small portion of sulphur, and then heating the mixture. The sulphur is thoroughly mixed with the oxide and then applied to the woven copper wire. The whole is then heated to burn off the sulphur, but in so doing the oxygen of the copper is absorbed to form the SO2, leaving the oxide in a reduced state on the support. The heat ing then being continued, the exposed portions of the particles of the mass are reoxidized, while the unexposed portions at the juncture, being protected from the air, remain metallic and serve to hold the mass together. The sulphur, when used in this manner, therefore, acts as a binding• toughening, or hardening agent, without being actually present in the mass after the treatment.
The Laurent-Cely accumulator is distinctive in the special nature of the lead paste em ployed. and in the manner in which it is applied to the plates. The active element is a mix ture of chloride of lead and chloride of zinc. The fused chloride of lead has a density of 5.6 ; by incorporating chloride of zinc with it in certain proportions the density is reduced to 4.5. This mixture, brought to a state of fusion, is run into cast-iron molds in the form of small buttons, with rounded edges. After cooling, the buttons are washed to remove the chloride of zinc, and to thus render them somewhat porous. Their density then varies from 4.2 to 3.4. The buttons which serve for the manufacture of the negative plates are then arranged in a metallic mold, into which antimonial lead is run : this surrounds the buttons with a frame which holds them fixed in their positions. The negative plates are mounted in cells filled with acidulated water and provided with zinc electrodes. The composite and zinc plates are then short circuited. The hydrogen which is disengaged upon the positive electrode reduces the chloride of lead, and there are thus obtained buttons of spongy lead of a density between 2.5 and 3•1, while that of ordinary lead is 11.85. The buttons used in the manu facture of the positive plates are first transformed into spongy lead, then heated in the air to oxidize them, and transformed into spongy litharge. They are fixed, like the negative but tons, in a frame of antimonial lead.