Parthasarathy M. Gomadam

Bio: Parthasarathy M. Gomadam is an academic researcher from Medtronic plc. The author has contributed to research in topics: Battery (electricity) & Carbon monofluoride. The author has an hindex of 10, co-authored 19 publications receiving 1382 citations. Previous affiliations of Parthasarathy M. Gomadam include University of South Carolina.

Development of First Principles Capacity Fade Model for Li-Ion Cells

Abstract: A first principles-based model has been developed to simulate the capacity fade of Li-ion batteries. Incorporation of a continuous occurrence of the solvent reduction reaction during constant current and constant voltage (CC-CV) charging explains the capacity fade of the battery. The effect of parameters such as end of charge voltage and depth of discharge, the film resistance, the exchange current density, and the over voltage of the parasitic reaction on the capacity fade and battery performance were studied qualitatively. The parameters that were updated for every cycle as a result of the side reaction were state-of-charge of the electrode materials and the film resistance, both estimated at the end of CC-CV charging. The effect of rate of solvent reduction reaction and the conductivity of the film formed were also studied. © 2004 The Electrochemical Society. All rights reserved.

Analysis of electrochemical impedance spectroscopy in proton exchange membrane fuel cells

Abstract: SUMMARY A literature review of electrochemical impedance spectroscopy (EIS) analysis of proton exchange membrane fuel cells (PEMFCs) is presented. Emphasis is placed on the papers that analyse the impedance response of the cathode and anode half-cells of the PEMFCs based on a continuum-mechanics approach. The other type of analysis, which is based on the equivalent-circuits approach, is addressed for comparison. The relative advantages and disadvantages of the two approaches are discussed. Papers dealing with continuum-mechanics-based EIS modelling of general electrochemical systems are briefly reviewed. Copyright # 2005 John Wiley & Sons, Ltd.

Modeling Heat Conduction in Spiral Geometries

Abstract: The spirally wound design is of importance to battery manufacturers as it improves the energy and power densities, by using lesser accessories when compared with the prismatic design. 1-2 For this reason, the spirally-wound design is used in a variety of battery systems ~e.g., Li-SOCl2 , 3 Li bromine chloride complexing additive ~BCX!, 4 lead-acid, 5 Zn-MnO2 , 6 Li-ion 1-2,7 !. However, because of their lower surface area to volume ratio, spiral batteries retain more heat than prismatic batteries. Therefore, in order to improve thermal management and achieve safe operation of large-scale spirally wound batteries, it is important to understand their thermal behavior, especially during high rate operation. A cost effective method of studying heat transport during the operation of a battery is to theoretically simulate the temperatures attained by the battery. However, very few publications 3-9 exist in the literature that couple electrochemical and thermal behavior in spirally wound batteries. Rather, most thermal models of spirally wound batteries estimate the heat generation rate a priori from experimental voltage-time data. 3-4,7-9 Cho and Halpert 8 and Cho 9 assumed that the entire battery operates at a uniform temperature, while Al Hallaj et al. 7 simulated a 1-D radial variation in temperature. Evans and White 3 and Kalu and White 4 accounted for both radial and spiral heat conductions in their spirally wound battery systems using a two-dimensional ~2-D! model for the energy balance. Evans and White 3 compared the predictions of the 2-D model

Accurate electrical battery model capable of predicting runtime and I-V performance

Abstract: Low power dissipation and maximum battery runtime are crucial in portable electronics. With accurate and efficient circuit and battery models in hand, circuit designers can predict and optimize battery runtime and circuit performance. In this paper, an accurate, intuitive, and comprehensive electrical battery model is proposed and implemented in a Cadence environment. This model accounts for all dynamic characteristics of the battery, from nonlinear open-circuit voltage, current-, temperature-, cycle number-, and storage time-dependent capacity to transient response. A simplified model neglecting the effects of self-discharge, cycle number, and temperature, which are nonconsequential in low-power Li-ion-supplied applications, is validated with experimental data on NiMH and polymer Li-ion batteries. Less than 0.4% runtime error and 30-mV maximum error voltage show that the proposed model predicts both the battery runtime and I-V performance accurately. The model can also be easily extended to other battery and power sourcing technologies.

A Critical Review of Thermal Issues in Lithium-Ion Batteries

Abstract: Lithium-ion batteries are well-suited for fully electric and hybrid electric vehicles due to their high specific energy and energy density relative to other rechargeable cell chemistries. However, these batteries have not been widely deployed commercially in these vehicles yet due to safety, cost, and poor low temperature performance, which are all challenges related to battery thermal management. In this paper, a critical review of the available literature on the major thermal issues for lithium-ion batteries is presented. Specific attention is paid to the effects of temperature and thermal management on capacity/power fade, thermal runaway, and pack electrical imbalance and to the performance of lithium-ion cells at cold temperatures. Furthermore, insights gained from previous experimental and modeling investigations are elucidated. These include the need for more accurate heat generation measurements, improved modeling of the heat generation rate, and clarity in the relative magnitudes of the various thermal effects observed at high charge and discharge rates seen in electric vehicle applications. From an analysis of the literature, the requirements for lithium-ion thermal management systems for optimal performance in these applications are suggested, and it is clear that no existing thermal management strategy or technology meets all these requirements.