Dr. Ravi's Talk

Oct 29, 2009 - 16:00

Oct 29, 2009 - 17:30

Creativity Hall (Room No 118)

Seminars

Dr. Ravi Methekar Washington University Saint Lois USA

Abstract: Electrochemical power sources have had significant improvements in design and operating range and are expected to play a vital role in the future in automobiles power storage military and space applications. Lithium-ion chemistry has been identified as a preferred candidate for high-power/high-energy secondary batteries. Application of batteries ranges from implantable cardiovascular defibrillators (ICDs) operating at 10 µA current to hybrid vehicles requiring pulses of up to 100 A. Today the design of these systems have been primarily based on (1) matching the capacity of anode and cathode materials (2) trial-and-error investigation of thickness porosity active material and additive loading (3) manufacturing convenience and cost (4) ideal expected thermal behavior at the system level to handle high currents etc. and (5) detailed microscopic models to understand optimize and design these systems by changing one or few parameters at a time. Several problems persist with lithium-ion batteries: capacity fade underutilization and thermal runaway caused by operation outside the safe window. Several attempts have been published in literature for circumventing some of above mentioned problems for the lithium ion batteries. Optimal porosity distribution: Improved design A model-based optimization procedure for the design of porous electrodes that are commonly used in advanced batteries such as the lithium-ion system is presented. Unlike the traditional design approach the proposed approach is based on the simultaneous optimization of multiple variables in porous electrode models to find optimal porosity distributions in porous electrodes. Reformulated model approach: A mathematical model of lithium-ion batteries is reformulated using the various mathematical technique and vast experience of the battery field to reduce the cost of computation. Optimization for improving underutilization: A dynamic optimization especially control vector parameterization procedure is employed for estimating the charging and discharging optimal profile for the lithium-ion battery. Optimal profile for charging and discharging will improve the underutilization of batteries. Kinetic Monte Carlo: Due to various reactions which take place as a part of charging and discharging various undesirable byproduct forms at the electrode and electrolyte interface. SEI layer forms from this byproduct which act as the resistance for intercalation of the lithium-ion particles. Large number of literatures are published to predict the mechanism of formation of SEI layer in parallel direction to the intercalation of lithium-ion. Very meager literature is available which predict the formation SEI layer in tangential direction of the molecule. We proposed to carried out the kinetic Monte Carlo simulation for predicting the formation of SEI layer in tangential directions.ABOUT THE SPEAKER: Dr Ravi Methekar obtained his PhD from IIT Bombay in October 2009 under the supervision of Dr. Sachin Patwrdhan. As a part of his PhD he published four peer reviewed journal papers and some conference papers. He completed his M. Tech from IIT Karaghpur in 2002 and B. E. from Amravati University 1999. Prior to his PhD he worked as the lecturer for 2 years. Presently he is working as a research associate at the Washington University in St. Louis with Dr. Venkat Subramanian in electrochemical power sources. His areas for interest are control optimization identification and modeling of electrochemical /chemical processes.