what is lead acid battery

Two types of lead-acid batteries are manufactured for industrial applications. These are generally referred to as motive-power and stationary batteries. Typical applications for motive-power batteries include material-handling trucks, mine locomotives, mine tractors, mine shuttle cars, floor sweepers and scrubbers, heavy-duty personnel carriers, transport vehicles, golf carts, and lawnmowers. Typical applications for stationary batteries are switchgear and emergency power for electric-utility substations, switchgear and emergency power for generating plants, computer and other no-fail systems, telephone-company equipment for a variety of operations, emergency lighting, and railway signal service.
Depending upon the application, three types of stationary batteries are available through most manufacturers, those made with lead-calcium-alloy grids and those made with lead-antimony grids. The active material of the positive electrode of a lead-acid battery is lead dioxide, and the negative is highly reactive spongy lead. The electrodes are electrically insulated from each other by separators.
Many different types of separators are used, such as resin-impregnated cellulose materials, microporous rubber, microporous plastic, and fiberglass-mat separators with micro-porous backing. Most separators are fabricated with vertical ridges or ribs on the surface that face the positive electrode, and the other surface is flat with no ribs.

The electrolyte in fully charged batteries is a solution of sulfuric acid with a specific gravity ranging from 1.215 to 1.300, depending on intended service. The positive and negative active materials are supported on lead-grid structures in all types except the planté. (The positive electrode in a planté battery is a solid piece of pure lead that is scored with evenly spaced ridges to create a large surface area, then electrochemically converted to lead dioxide by an electrolytic forming process.) For most applications, however, the grid is cast from an alloy of lead with 4.5 to 7 percent antimony and small amounts of arsenic and tin. The function of the antimony is to harden the lead and facilitate casting. For telephone standby power where low self-discharge rates and float currents are required, a small amount of calcium (less than 0.10 percent), instead of antimony, is used in the grid alloy. Generally no arsenic or tin is used in the calcium alloy.

Installation and Operation. Upon receiving a new battery, it is extremely important to examine the exterior packing case. An examination should be made for wet spots on the sides and bottom of the case. Wet spots may indicate leaking jars, broken in shipment because of rough handling by the carrier.If any damage has occurred, take immediate and proper claim measures. If any jars are damaged and the electrolyte has leaked out, make immediate repairs and replace broken jars at once. If replacement jars are not immediately available, withdraw the elements from the damaged jar (see under “Repairs” below) and place the elements in a glass, porcelain, rubber, or other nonmetallic vessel containing water suitable for battery use. Sufficient water must be added to cover the plates and separators completely.Damage or complete destruction of the cell may result if these procedures are not followed. Note: Use distilled water or tapwater that has been analyzed and approved for battery use.

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