lead–acid battery

lead–acid battery
Name	Lead–acid battery
Type	Rechargeable
Invented	1859
Inventor	Gaston Planté
Voltage	2 V per cell
Energy density	Low
Power density	High
Uses	Starting engines, backup power, traction

lead–acid battery is a rechargeable electrochemical cell that uses lead and lead dioxide electrodes with sulfuric acid electrolyte to store and deliver electrical energy. Developed in the 19th century, it has powered applications from early electric vehicles to contemporary uninterruptible power supplies and automotive starters. The technology remains widely used because of robust cycle life, high surge currents, and established manufacturing by multinational firms.

History

The technology originated with French engineer Gaston Planté in 1859, who demonstrated a practical rechargeable accumulator in Paris and patented improvements during the Second French Empire. Subsequent refinements by inventors such as Camille Alphonse Faure in the 1880s accelerated adoption for telegraphy and early electric vehicles developed by pioneers in Berlin, London, and New York City. Industrialization and large-scale production were driven by manufacturers including firms from Germany, United Kingdom, and the United States, and use expanded through the 20th century during events like the First World War and Second World War when reliable traction and backup power were critical. Postwar growth tied the chemistry to automotive industry giants and power infrastructure projects in regions such as California, Japan, and China.

Design and construction

A typical cell is composed of positive plates of lead dioxide and negative plates of spongy lead separated by porous separators and immersed in sulfuric acid electrolyte; multiple cells are assembled in a single container to achieve nominal voltages used in General Motors vehicles and industrial equipment. Construction variants include flooded (vented) designs produced by companies like Exide Technologies and sealed valve-regulated designs promoted by firms such as Hawker and manufacturers servicing Honeywell and Siemens installations. Plate grids are cast from lead alloys containing antimony, calcium, or tin to improve mechanical strength and corrosion resistance—a practice influenced by alloy suppliers in Sweden and Belgium. Separators employ materials that evolved through polymer innovations from suppliers in Germany and United States Department of Energy research programs. Case materials and terminals adhere to standards promulgated by organizations including SAE International and International Electrotechnical Commission.

Electrochemistry and operating principles

During discharge, the positive electrode composed of lead dioxide undergoes reduction while the negative spongy lead electrode is oxidized, producing lead sulfate and releasing electrons through an external circuit—this reversible chemistry is governed by half‑cell reactions studied by researchers at institutions such as École Polytechnique and Massachusetts Institute of Technology. The sulfuric acid concentration decreases as the electrolyte reacts, altering specific gravity measured using hydrometers standardized by laboratories like National Institute of Standards and Technology. Charging reverses the reactions when an external charger controlled by manufacturers such as Schneider Electric supplies current; charging regimes (constant voltage, IU, multi-stage) were developed by engineers associated with General Electric and Eaton Corporation. Overcharge leads to oxygen and hydrogen evolution catalyzed at electrode surfaces, phenomena investigated at universities including University of Oxford and Tokyo Institute of Technology.

Performance characteristics and maintenance

Lead–acid batteries offer high surge current capabilities exploited by original equipment manufacturers such as Ford Motor Company and Toyota Motor Corporation for engine starting; however, energy density is lower than alternatives produced by firms like Panasonic Corporation and Tesla, Inc.. Cycle life depends on depth of discharge and temperature, parameters characterized in studies by Argonne National Laboratory and Sandia National Laboratories. Maintenance for flooded cells includes periodic watering and specific gravity checks, practices codified in service manuals from Bosch and Magna International. Valve-regulated lead–acid (VRLA) variants minimize watering but require monitoring of float charge and temperature as prescribed by standards from Underwriters Laboratories and International Organization for Standardization. Failure modes such as sulfation, grid corrosion, and stratification have been documented in technical reports produced by National Renewable Energy Laboratory.

Applications

Lead–acid batteries serve as starter batteries in internal combustion engine vehicles produced by manufacturers like BMW, Volkswagen Group, and Hyundai Motor Company; they also provide backup power for data centers operated by corporations such as Google and Amazon Web Services using battery cabinets specified by firms like Vertiv. Stationary systems for telecommunications by companies including AT&T and Vodafone and renewable energy storage in microgrid projects in locations like Puerto Rico and Isle of Man have relied on lead–acid batteries. Traction batteries power forklift fleets from manufacturers such as Toyota Industries Corporation and Crown Equipment Corporation, while motive applications include golf carts and light rail vehicles ordered by transit agencies in Los Angeles and London. Military and aerospace organizations including branches of the United States Armed Forces have used hardened lead–acid battery systems for legacy platforms.

Environmental and safety considerations

Lead is toxic and regulated through policies and directives from bodies like the European Union and the United States Environmental Protection Agency; recycling infrastructure is provided by companies such as Rieter-affiliated recyclers and national programs in Australia, Canada, and Germany. Lead–acid batteries are among the most recycled consumer products under systems coordinated by organizations including the International Lead Association and national regulators in Japan and South Korea. Improper disposal risks soil and water contamination, incidents investigated by agencies like Environmental Protection Agency regional offices and remediation performed under standards from United Nations Environment Programme. Safety hazards include acid burns and hydrogen explosion risk during overcharge, addressed by standards and training from institutions such as Occupational Safety and Health Administration and emergency response protocols used by Red Cross chapters.

Category:Electrochemical cells