Electrochemical power source

A further impetus for commercial battery development came with the introduction of domestic radio receivers in the 1920s, and an equivalent growth has been seen over the last 30 years with the development of microelectronics-based equipment. Today, it is estimated that annual battery production totals 8-15 units per head of population throughout the developed countries of the world. 

The world market for batteries of all types now exceeds 100 billion. Over half of this sum is accounted for by lead-acid batteries - mainly for vehicle starting, lighting and ignition (SL1), and industrial use including traction and standby power, with about one-third being devoted to primary cells and the remainder to alkaline rechargeable and specialist batteries. 

The last four decades have witnessed remarkable progress in tire development of battery-driven implantable and external devices for medical detection and treatment. For instance, the medical condition known as bradycardia (where the heart beats too slow) 

One of the factors determining the life span of implanted medical devices is the life span of its power source. The impressive progress in extending it has been possible by the advancement of both, primary- and secondary-battery technologies. In other words, electrochemical power sources are tmly an integral vital part of modem health care. 

On the other hand, the medical condition where the heart beats too fast is known as tachycardia. If untreated, tliis condition may lead to ventricular fibrillation, that is, a condition in which the heart stops beating and shakes uncontrollably and is usually fatal. In 1980, a special device was developed and implanted in patients. It could sense the condition and provide a shock that would stop the fibrillation and restore the normal sinus rhythm via an electrode sutured onto the heart. The device was first powered by a lithium/vanadium pentoxide system later it was replaced by a system using a cathode material of silver vanadium oxide (SVO or Ag2V40ii). This is the actual system used in modem ICDs (implantable cardioverter/defibrillator). Another material used is the lithium/manganese dioxide system. Also, a new system using a sandwich cathode design with an inner cathode material of carbon monofluoride and an external cathode layer of silver vanadium oxide is in wide use. 

The aim of this type of devices is to further extend the operational lifetime of the implanted medical devices to match the life time of the patient. To that end, fuel cell technology will have to be involved. 

It may be observed that engineering of fuel cells has greatly improved over the past number of decades, leading for instance to the development of electric automobiles with zero emissions and 

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Fundamentals and General Aspects of Electrochemical Power Sources... 

Electrochemical power sources convert chemical energy into electrical energy. At least two reaction partners undergo a chemical process during operation. The energy of this reaction is available as electric current at a defined voltage and time [1]. 

Electrochemical power sources differ from others, such as thermal power plants, by the fact that the energy conversion occurs without any intermediate steps for example, in the case of thermal power plants fuel is first converted in thermal energy, and finally electric power is produced using generators. In the case of electrochemical power sources this otherwise multistep process is achieved directly in only one step. As a consequence, electrochemical systems show some advantages, such as energy efficiency. 

A comprehensive modern survey of separators for electrochemical power sources exists only in incomplete parts [1-3], and textbooks on batteries treat this important element only as a side aspect [4-11]. This section is an attempt to describe, besides some fundamental aspects, the development history of the battery separator,... 

M. Barak, Electrochemical Power Sources, The Institution of Electrical Engineers, London/ P. Peregrinus, Stevenage, UK, 1980. 

One may conclude from all these studies that the loss in fuel utilization and Coulombic efficiency in a DMFC due to methanol crossover is still a major barrier in the development of such types of electrochemical power sources. 

Aprotic polar solvents such as those listed in Table 8.1 are widely used in electrochemistry. In solutions with such solvents the alkali metals are stable and will not dissolve under hydrogen evolution (by discharge of the proton donors) as they do in water or other protic solvents. These solvents hnd use in new types of electrochemical power sources (batteries), with hthium electrodes having high energy density. 

These batteries are used mainly for specialized technical equipment where power sources of small size but high power are needed. During early production years, cases of rather violent spontaneous explosion were observed, so that domestic uses were ruled out. The specihc energy can be as high as 1000 Wh/kg, which is the highest value among known types of electrochemical power sources. 

Skundin, A. M., O. N. Efimov, and O. V. Yarmolenko, The state-of-the-art and prospects for the development of rechargeable lithium batteries, Russ. Chem. Rev., 71, 329 (2002). Vincent, C. A., and B. Scrosati, Modem Batteries An Introduction to Electrochemical Power Sources, Edward Arnold, London, 1997. 

Modem electrochemistry has vast applications. Electrochemical processes form the basis of large-scale chemical and metaUnrgical production of a number of materials. Electrochemical phenomena are responsible for metallic corrosion, which causes untold losses in the economy. Modem electrochemical power sources (primary and secondary batteries) are used in many helds of engineering, and their production figures are measured in billions of units. Other electrochemical processes and devices are also used widely. 

If a cell is to be used as a potential standard, then it must be prepared as simply as possible from chemicals readily available in the required purity and, in the absence of current passage, it must have a known, defined, constant EMF that is practically independent of temperature. In this case the efficiency, power, etc., required for cells used as electrochemical power sources is of no importance. The electrodes of the standard cell must not be polarizable by the currents passing through them when the measuring circuit is not exactly compensated. 

Carbon electrodes are widely used in electrochemistry both in the laboratory and on the industrial scale. The latter includes production of aluminium, fluorine, and chlorine, organic electrosynthesis, electrochemical power sources, etc. Besides the use of graphite (carbons) as a virtually inert electode material, the electrochemical intercalation deserves special attention. This topic will be treated in the next paragraph. 

The electrochemical intercalation/insertion has not only a preparative significance, but appears equally useful for charge storage devices, such as electrochemical power sources and capacitors. For this purpose, the co-insertion of solvent molecules is undesired, since it limits the accessible specific faradaic capacity. 

Trasatti, S. (Ed.), Electrodes of Conductive Oxides, Elsevier, Amsterdam, 1980. Vincent, C. A., F. Bonino, M. Lazari, and B. Scrosati, Modern Batteries, An Introduction to Electrochemical Power Sources, E. Arnold, London, 1984. Whittingham M. S., and N. G. Jacobson, Intercalation Chemistry, Academic Press, Orlando, 1982. 

Management Department, ELIT Electrochemical Power Sources Co., 40, Rpospect Leninscogo Komsomola, 305026 Kursk, Russia elit pub.sovtest.ru... 

Dr. Ilia Iliev was from the generation of Bulgarian scientists who entered the professional life in the late 50s. Broth in by the excitement of the physics in the mid-twentieth century and the growth of the post-WWII Eastern Europe, Ilia Iliev changed fields and become one of the key developers of the metal-air systems at the Central Laboratory of Electrochemical Power Sources, Bulgarian Academy of Sciences. 

Central Laboratory of Electrochemical Power Sources, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria... 

Korovin N.V. Electrochemical Power Sources. Moscow Energoatomizdat. 1991.(Russian). 

Barsukov V., Khomenko V., Chivikov Santonenko P. Physico-chemical base of development of the air-meral batteries with the catalysts on anyline base. Electrochemical Power Sources. (Russian). 2001 1 24 - 30. 

Voligova I.V., Korovin N.V., Kleimenov B.V., Dyachkov E.V. Air-Al batteries with saline electrolyte. In Fundamental problems of electrochemical power sources (FPEPS), I Kasarinov, ed. Saratov SGU, 1999, 169. 

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