Home > Technology > Submarine propulsion battery   The positive undivided uniform plate is the tubular type, in which the current-conducting lead spines are attached to the top of the frame. The spines are made of low antimonial lead alloy, thus to reduce H2 evolution and to achieve optimum charge in first charging step. The frame itself contains on inlay that is lead coated and sealed to achieve maximum conductivity. The lead spines are surrounded by active material, which is mechanically held in place by tubular pockets. The tubular pockets are manufactured from an acid resistant material and an artificial silk web which is chorine-free. The active material, which is kept porous, consists of lead dioxide (PbO2) when in charged condition. At the base, the plate is surrounded by plastic bar.       The undivided uniform negative plate is a grid-type. The carrier material is a profiled copper stretch metal which holds the active material and at the same time acts as a conductor. The plate is surrounded entirely by a protection frame. The active material consists principally of finely distributed porous lead (Pb) when is charged condition. The conductivity of copper is 15 times higher than antimonial lead used for conventional grids. This is a powerful tool to reduce the weight of the grid and increases the conductivity.       The separator situated between each positive and negative plate are microporous They are of ribbed, acid resistant plastic.       Only dilute sulphlic acid (H2SO4) will be used as an electrolyte, the specific gravity of which in charged cells at a normal acid level and temperature of 30℃ is 1.285±0.01g/cm3.       The pole bridges and posts are made of electrolytic copper and they are covered by a thick layer of lead, especially at those parts which might come into contact with the acid. The pole post have a balcony pressing from underneath against the rubber lining of cover, which is held in place by braces on the top of the cover. Pole post have a channel of about 10mm in diameter through which cooling water flows.       A leak-proof operating plug is screwed into one of the holes of the cell cover. Filter plug and connecting nipple for the circulating air of the acid circulating system are screwed into the operating plug. The filter plug, filled with polyethylene granule, holds back acid spray, but permits gas to escape. When topping up acid and measuring the density of the electrolyte the filter plug removed. Each cell has an acid level indicator mounted on the outer cover, showing the acid level. The acid level indicator is screwed tightly into the cover to avoid leakage. It consists of a plastic ring floating in the cell, in the connected to a red indicator ring held by the float angle-rods. Both ring are held by the float angle-rods. Both ring are held by the centering rod, fixed inside the transparent hood. A disk at the end of the centering rod prevents the float dropping at low acid level. The acid level can be read from outside. There is a black marking ring for the normal acid level on the transparent hood. The intermediate marks are spaced 55 mm apart. The upper and the lower end of the transparent hood mark the maximum and minimum acid level. The centering rod may be replaced by a temperature telemeter.       To detect cells with damaged lining, a lead strip is put into each cell between the container lining and container, to permit insulation measuring between the poles and the lead strip are connected points.