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Cars start due to relativity


A Swedish research team of Professor Rajeev Ahuja, Dr. Andreas Blomqvist, Dr. Peter Larsson and a Finish team of Prof. P Pekka Pyykkö & Dr. Patryk Zaleski-Ejgierd have used first time quantum mechanical calculations to understand lead acid battery. The findings are being published in January issue of Physical Review Letters.

A battery is a device that converts the chemical energy contained in its active materials directly into electrical energy by means of an electrochemical oxidation-reduction reaction. This type of reactions involves the transfer of electrons from one material to another through an internal circuit. The basic principles of primary and secondary batteries can be traced back to the work of Alessandro Volta at the end of 18th century. During the French industrial revolution, the two main systems were created by Raymond Gaston Plante in 1859 and Georges Leclanche in 1868. The First battery of the modern era was the “voltaic pile” constructed in 1800 by Volta. His name has been given to the unit of electrical potential-the volt. The lead battery is an essential part of every car and has numerous other applications. This well-known invention, now 150 years old, is still unbeatable in its ratio of available power to weight. About 75% of the World lead production and a turnover of about 30 billion USD are due to these batteries.

In lead acid battery, anode is Pb, cathode is PbO2 and electrolyte is H2SO4 (aqueous solution). The open circuit voltage (electromotoric force) of lead acid battery, the  main configuration of  any battery is 2.1 V. Although the lead battery is over 150 years old, the origin of this open circuit voltage (OCV) of 2.1 V is still unknown.  In present letter, we have shown how one can explain the origin of OCV of 2.1 V based on foundations of relativistic quantum mechanics.  Surprisingly, seems to be the first time its chemistry has been theoretically modeled from the first principles of quantum mechanics. The main finding of this letter is that most of the electromotoric force, 1.7-1.8 Volts out of 2.1 V of the common lead battery comes from relativistic effects. 

- While the importance of relativistic effects in heavy-element chemistry is well-known since over two decades, this is a striking example on "everyday relativity", says Professor Rajeev Ahuja of Uppsala University.

The extensive numerical studies were performed at Uppsala University’s Uppsala Multidisciplinary Center for Advanced Computational Science, UPPMAX.

Read more about the findings in Physical Review Focus, Chemistry World, The Economist, Nature and New Scientist.


Reference: ‘Relativity and the lead-acid battery’. R.Ahuja et. al., Phys. Rev. Lett. 106 (2011) 018301.


For more information, please contact Professor Rajeev Ahuja, phone: +46 (0)18-471 36 26; cell phone: +46 (0)70-425 09 35; e-mail: , Dr. Peter Larsson,  +46 (0)18-4713580, e-mail :, Dr. Andreas Blomqvist, Phone  : +46 (0)737788714