| 摘要 |
1377009 Lead-acid batteries MATSUSHITA ELECTRIC INDUSTRIAL CO Ltd 15 Sept 1972 [27 Oct 1971 (2) 9 Nov 1971] 42948/72 Heading H1B [Also in Division C7] In a lead storage battery the electrode plates of at least one polarity are made of pressed lead fibres wherein at least the periphery of these electrode plates are more strongly pressed than the remainder of these electrode plates and these hard-pressed regions are covered with a synthetic resin film. The lead fibres may be formed of an alloy consisting of lead and 0À1 to 0À3% by weight Ag, As and/or Sn, and made into an unwoven fabric. A mixture of lead fibres of 150-200 Á diameter with 30% by weight of 70-100 Á diameter is pressed to give the electrode fabric a density of 5À0-5À5 g./c.c. The hard-pressed peripheral regions 12 of the electrode, Fig. 3, have a density of at least 10 g./cc.' and for larger electrodes, as shown, an additional grid of hard-pressed portions spaced by 25-35 mm. is formed across the electrode. The hardpressed regions 12, covered with a thermoplastic synthetic resin film 13, have holes 14 therethrough by which the films 13 on opposite sides of the electrode are united. The peripheral hardpressed regions are preferably wedge-shaped and the region may be extended at the corner 12c of the electrode to which the lead piece 15 is welded, Fig. 12a. The electrodes intended as positive plates are protected by an ion-permeating porous thermoplastic synthetic resin bag, and electrodes intended as negative plates have protrusions integral with the film 13 at each corner to space adjacent electrodes. The lead fabric 11 of the positive and negative plates may be activated by anodizing prior to electrolytic reduction thereof and initially charging the assembled battery. The discharge characteristics may be improved by adding barium sulphate or lignin to the negative electrode. Thus the negative electrode plate is immersed for 10 hours in a 15% aqueous barium chloride solution, dried at 80‹ C. for 2 hours and anodized in H 2 SO 4 of 1À03-1À05 specific gravity, to which 10-13 g./l. of NaClO 4 has been added, at 30+ 2‹ C. and a current density of 14 mA/cm<SP>2</SP>. for 20 hours. As shewn in Fig. 16, the assembled lead storage battery comprises positive electrodes 21 surrounded by ion-permeating covers 23 and negative electrodes 22 disposed in an electrolyte 31 of H 2 SO 4 of 1À28 specific gravity containing 3-5 g./litre of lignin sulphonate. The battery contains a gas-removing catalyst 32 comprising ethylene tetrafluoride powder press-moulded together with graphite and a metal catalyst such as palladium. A gas exhaust valve 33, Fig. 17 (not shown) is also provided. |
