Lead acid electrochemical battery

Some electrochemical cells can function as galvanic or electrolytic cells. A well-known example is the lead-acid car battery. Under discharge... 

Because of the unique properties of lead to exist in three valence states (metal, ion with +2 charge, and ion with a +4 charge), lead is used not only for electrochemical anodes to electroplate other metals from sulfuric acid solution but also to serve as anode, cathode, and active material in lead acid storage batteries. Storage batteries represent over 60% of lead usage worldwide and over 80% of lead usage in the United States. Electrowinning anodes and batteries are two of the unique successes of lead product development efforts. 

In 1859, the French scientist Gaston Plants (1834-1889) made the first prototype of a lead acid rechargeable battery. An alkaline nickel-cadmium rechargeable battery was developed in 1899 by the Swedish engineer W. Jungner (1869-1924) and an alkaline nickel-iron battery was developed two years later by the well-known American inventor Thomas A. Edison (1847-1931). Up to the seventh decade of the nineteenth century, electrochemical batteries remained the only sources of electrical current and power. 

The batteries in most automobiles are lead-acid storage batteries. These batteries consist of six electrochemical cells wired in series ( Figure 16.14). Each cell produces 2 volts for a total of 12 volts. The cells each contain a porous lead anode where oxidation occurs according to the following reaction. 

To transport people and material growing transportation systems are needed. More and more of the energy for these systems is drawn from secondary batteries. The reason for this trend is economic, but there is also an environmental need for a future chance for electric traction. The actual development of electrochemical storage systems with components like sodium-sulfur, sodium-nickel chloride, nickel-metal hydride, zinc-bromine, zinc-air, and others, mainly intended for electric road vehicles, make the classical lead-acid traction batteries look old-fashioned and outdated. Lead-acid, this more than 150-year-old system, is currently the reliable and economic power source for electric traction. 

Booth, F. (1970) Comparative Study on Battery Separators for Lead-Acid Starter Batteries (printed as manuscript, 12pp.) Dafler. J. R. (1978) Resin-bonded ceiiuiose separators an overview with prognoses. Journai of the Electrochemical Society, 125,833-842... 

The lead—acid battery is one of the most successful electrochemical systems and the most successful storage battery developed. In 1988 total battery sales, excluding Eastern European central economy countries, were more than 17 biUion (1). Lead—acid battery sales accounted for about 57% of that figure. About 80% of the lead [7439-92-1] (qv), Pb, consumption in the United States was for batteries in that year. 

An excellent review covers the charge and discharge processes in detail (30) and ongoing research on lead—acid batteries may be found in two symposia proceedings (32,33). Detailed studies of the kinetics and mechanisms of lead —acid battery reactions are pubUshed continually (34). Although many questions concerning the exact nature of the reactions remain unanswered, the experimental data on the lead—acid cell are more complete than for most other electrochemical systems. 

The lead—acid battery is comprised of three primary components the element, the container, and the electrolyte. The element consists of positive and negative plates connected in parallel and electrically insulating separators between them. The container is the package which holds the electrochemically active ingredients and houses the external connections or terminals of the battery. The electrolyte, which is the Hquid active material and ionic conductor, is an aqueous solution of sulfuric acid. 

Element. The process of fabricating lead—acid battery elements as depicted in Figure 4 involves numerous chemical and electrochemical reactions and several mechanical assembly operations. AH of the processes involved must be carefully controlled to ensure the quaUty and reUabiUty of the product. 

The proper selection of the lead alloy depends on the intended use and the economics of the lead—acid battery appHcation. The metallurgical and electrochemical aspects of the lead are discussed in the Hterature in a comprehensive manner (81,85—87) as are trends of lead alloy use for manufacture of battery grids (88). 

Secondaiy batteries consist of a series of electrochemical cells. The most popular types are the lead-acid type used for starting, lighting, and electrical systems in motor vehicles and the small rechargeable batteries used in laptops, camcorders, digital phones, and portable electronic appliances. 

K.R. Bullock, in Proc. Symp. Advances in Lead-Acid Batteries, The Electrochemical Society, Pennington, NJ, 1984, p. 1. 

The lead-acid battery has a peculiarity the electrolyte sulfuric acid not only serves as ion conductor (as charge-transport medium), but it actively participates in the electrochemical reaction ... 

Very little work (relative to research of electrode materials and electrolytes) is directed toward characterizing and developing new separators. Similarly, not much attention has been given to separators in publications reviewing batteries.A number of reviews on the on cell fabrication, their performance, and application in real life have appeared in recent years, but none have discussed separators in detail. Recently a few reviews have been published in both English and Japanese which discuss different types of separators for various batteries. A detailed review of lead-acid and lithium-ion (li-ion) battery separators was published by Boehnstedt and Spot-nitz, respectively, in the Handbook of Battery Materials. Earlier Kinoshita et al. had done a survey of different types of membranes/separators used in different electrochemical systems, including batteries."... 

---