Raghunathan Rengasamy

Electrochemical energy, being a safe and clean renewable energy source, is gaining considerable attention in recent years. The electrochemical energy technologies available are numerous and the choice of technology is usually guided by heuristics. The paper presents a critical review and comparison of three competing electrochemical energy technologies (secondary batteries, fuel cells and flow batteries) based on various characterization criteria like energy & power densities, cost, weight, efficiency, controllability, reliability etc. A rational framework is proposed to characterize the technology best suited for a particular application to achieve the best energy utilization. The idea is posed as a constrained multi objective optimization of design, followed by choice based on gravimetric and volumetric cost comparison of the three systems under consideration. For various combinations of characterization criteria, optimal choice of technology for an extensive scope of power and energy is found using the proposed framework and presented as area plots for easy understanding. This framework is then used to examine the prospects and directions of improvement for emerging technologies. Discussions are presented using the example of Vanadium Redox Flow Battery (VRFB).