Zinc-carbon batteries seals

OTHER COMMENTS used in barometers, thermometers, hydrometers and pyrometers used in fluorescent lamps, switches and mercury boilers used in the manufacture of mercury salts, mirrors, pulp and paper, and oscillators used as a component of zinc-carbon batteries as well as industrial and control instruments and amalgams (e.g. for dental preparations) laboratory use includes manometers, gauges, valves, seals, and navigational devices. 

The electrolyte was a solution of ammonium chloride that bathed the electrodes. Like Plante s electrochemistry of the lead-acid battery, Leclanche s electrochemistry survives until now in the form of zinc-carbon dry cells and the use of gelled electrolyte.12 In their original wet form, the Leclanche electrochemistry was neither portable nor practicable to the extent that several modifications were needed to make it practicable. This was achieved by an innovation made by J. A. Thiebaut in 1881, who through encapsulating both zinc cathode and electrolyte in a sealed cup avoided the leakage of the liquid electrolyte. Modern plastics, however, have made Leclanche s chemistry not only usable but also invaluable in some applications. For example, Polaroid s Polar Pulse disposable batteries used in instant film packs use Leclanche chemistry, albeit in a plastic sandwich instead of soup bowls.1... 

The cell components are hermetically sealed in a steel shell that is in contact with the zinc and acts as the negative terminal of the battery. A fresh zinc-carbon dry cell generates a potential difference of 1.5 V. 

Primary batteries, zinc-alkaline manganese dioxide, mercury-zinc, carbon-zinc Leclanche, magnesium types, silver oxide-zinc, zinc chloride Leclanche, zinc-air secondary batteries, alkaline, nickel-iron, nickel-cadmium, silver-zinc, sealed lead-acid, zinc-air, nickel-metal hydride secondary, lithium-manganese dioxide, lithium-silver chromate, lithium-lead bismuthate. 

Primary batteries, carbon-zinc Leclanchd, magnesium types, lithium types, silver oxide-zinc secondary batteries, nickel-cadmium, silver-zinc, silver-cadmium, sealed lead-acid. 

Yuasa Battery Co. Ltd, 6-6 Josai-cho, Takatsukishi, Osaka-fii 569 also International Division, 12-112 Chome, Higashi-Shinbashi Minako-ku, Tokyo 105 Primary batteries, carbon-zinc Leclanchd, silver oxide-zinc secondary batteries, nickel-iron, nickel-cadmium, silver-zinc, silver-cadmium, sealed lead-acid. Sodium-sulphur, lithium-manganese dioxide. 

Practically every battery system uses carbon in one form or another. The purity, morphology and physical form are very important factors in its effective use in all these applications. Its use in lithium-ion batteries (Li-Ion), fuel cells and other battery systems has been reviewed previously [1 -8]. Two recent applications in alkaline cells and Li-Ion cells will be discussed in more detail. Table 1 contains a partial listing of the use of carbon materials in batteries that stretch across a wide spectrum of battery technologies and materials. Materials stretch from bituminous materials used to seal carbon-zinc and lead acid batteries to synthetic graphites used as active materials in lithium ion cells. 

Most battery systems employ carbon materials in one form or another, as noted in Table 10.1. The use of carbon materials in batteries stretches across a wide spectrum of battery technologies. The variety of carbon runs the gamut from bituminous materials, used to seal carbon-zinc and carbon black powders in lead acid batteries, to high performance synthetic graphites, used as active materials in lithium-ion cells. The largest use is as a conductive diluent to enhance the performance of cathode materials. In many instances, it is used as a conductive diluent for poorly conducting cathode materials where carbon blacks, such as acetylene black, are preferred. It is essential that... 

FIGURE 10.3 Construction of the carbon-zinc cells. The zinc chloride and Leclanche have the same construction except for the seal. The zinc chloride has a plastic-compression seal while the Leclanche has a poured hot bituminous seal instead of the plastic-compression seal shown. (Courtesy of Eveready Battery Co., St Louis, MO. With permission.)... 

However, the reaction with water can be made to be extremely slow. Because the alkaline electrolyte is corrosive toward human tissue as well as toward the materials in devices, it is more important to have a good seal toward preventing electrolyte leakage in an alkaline battery than in a carbon—zinc cell. The formation of a good seal is, however, incompatible with the formation of a noncondensable gas like hydrogen. 

In batteries with metallic container one terminal must be electrically insulated from it. In low-temperature batteries for this purpose rubber or plastic gaskets are used, which provide a sufficient effective sealing of joints. But in sealed batteries with an alkaline electrolyte solution (e.g., in cylindrical alkaline manganese-zinc batteries), after some time the alkaline solution begins to creep around most sealing gaskets and then forms on the outside white patches of alkali carbonates. 

The second battery (Fig. 10.17) is a series of six cells with bipolar (or duplex) electrodes. Each cell has the same components as the first cell, i.e. zinc can, separator, positive paste and carbon current collector. The latter is not a carbon rod but the bottom face of the duplex electrode. The whole set of cells is sealed in wax. In both cells the zinc electrode rapidly develops porosity as the corrosion process occurs while the performance is largely determined by the quality of... 

Construction of the zinc chloride cylindrical battery (Fig. 8.3) differs from that of the Leclanchd battery in that it usually possesses a resealable, venting seal. The carbon rod serving as the current collector is sealed with wax to plug any vent paths (necessary for... 

The flat cell is illustrated in Fig. 8.5. In this construction, a duplex electrode is formed by coating a zinc plate with either a carbon-filled conductive paint or laminating it to a carbon-filled conductive plastic film. Either coating provides electrical contact to the zinc anode, isolates the zinc from the cathode of the next cell, and performs the function of cathode collector. The collector function is the same as that performed by the carbon rod in cylindrical cells. When the conductive paint method is used, an adhesive must be placed onto the painted side of the zinc prior to assembly to effectively seal the painted surface directly to the vinyl band to encapsulate the cell. No expansion chamber or carbon rod is used as in the cylindrical cell. The use of conductive polyisobutylene film laminated to the zinc instead of the conductive paint and adhesive usually results in improved sealing to the vinyl however, the film typically occupies more volume than the paint and adhesive design. These methods of construction readily lend themselves to the assembly of multi-cell batteries. 

Figures 11.15 and 11.16 illustrate two designs of Leclanche battery. The first shows the traditional cylindrical design. The negative zinc electrode is a zinc lining to the metal can which is amalgamated with mercury to minimize hydrogen gas formation by reaction of the metal with water the separator is a paper stiffened with cellulose or starch placed adjacent to the zinc can. The positive current collector is a carbon rod at the centre of the can, while most of the volume is taken up by the positive paste. This is a mixture of powdered manganese dioxide, ammonium chloride and acetylene black (carbon) to increase the conductivity the pores are filled with an aqueous electrolyte (NH4CI -l-ZnCl2) gelled by addition of starch. The can is totally sealed.

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