| 摘要 |
653,235. Accumulators. VOGT, H. Dec. 6, 1948, No. 31513. Convention date, Dec. 15, 1947. Drawings to Specification. [Class 53] An accumulator electrode consists of a porous mass forming a supporting skeleton and made by a sintering process, the pores being filled with a second sintered porous material which is impregnated with the active material such as the hydroxide of iron, nickel or cadmium. The supporting skeleton may be made of metal, carbon or ceramic material, the porous filling material being obtained by impregnating the supporting skeleton with metal salts or an emulsion of metal powder or oxide which on heating are converted into the form of a metal sponge. Instead of a metal filling finely divided carbon may be used. If the supporting skeleton is made of glass, silica or ceramic material such as aluminium oxide it is provided with a surface coating of thin metal by impregnating it with a metal salt and heating. In an example, the supporting skeleton is made by mixing iron powder with particles of charcoal or cellulose fibres, compressing the mixture and sintering it for several hours at 1000‹ C. When cooled it is impregnated with a metal salt and the whole heated in a reducing atmosphere to form a metal sponge within the pores of the iron skeleton. Hydroxide of nickel or cadmium is then precipitated in the porous mass in known manner. In a modified process the supporting skeleton is made from sintered nickel or steel wool and the pores filled with a thick emulsion of metal or metal oxide with water or acid and the whole dried and sintered. The active material is subsequently introduced into the cooled porous mass. In another example, a porous carbon body is filled with a mixture of soot and tar or pitch and a hydrocarbon such as petrol, benzene or acetone. The liquid is driven off by heat and the carbon particles in the pores lightly sintered at 800-1000‹ C. in an atmosphere free from oxygen. After cooling, the body is impregnated in the usual way with a metal hydroxide forming the active material. To improve the conductivity of the carbon body its pore surface may be provided with a metal coating by a galvanic or other process. In another example, a porous skeleton of glass or stone is impregnated under vacuum with a nickel salt solution and heated in a reducing atmosphere to form a nickel coating over its whole surface. It is then repeatedly dipped in a solution of nickel nitrate and heated till the pores are filled with nickel oxide. The body is then heated in a reducing atmosphere to covert the oxide into nickel sponge and is then impregnated with cadmium or iron hydroxide to complete the electrode. |
