PFI:AIR - TT: Self-X Smart Battery

University Of Nebraska-Lincoln, Lincoln NE

Investigators

Abstract

This PFI: AIR Technology Translation project focuses on translating an innovative self-X smart battery technology to fill the need for renewable energy, electric transportation and electric grid applications. Battery units are composed of individual cells connected together to provide the overall energy storage capacity of the battery. The self-X smart battery can automatically configure itself to self-balance from individual cell state variations, self-heal from failures of individual cells, and self-optimize to achieve optimal energy conversion efficiency. These features prolong battery operating time and lifespan while ensuring the overall safety of the system. An improved battery system is important because it will provide a cost-effective, highly efficient, flexible, reliable, scalable, and ubiquitously deployable energy storage solution to address national needs in the fields of renewable energy and transportation electrification. The project will result in a prototype of a self-X smart battery the uses a power electronics-based switching circuit to demonstrate self-balancing from cell state variations, self-healing from failures of cells, and self-optimization to achieve the optimal energy conversion efficiency through self-configuration of cell connections. As compared to the leading battery design and management technology, these features provide the advantages of improved energy conversion efficiency and reliability, longer operating time and lifespan, and reduced operation and maintenance costs. This project addresses the following limitations in existing solutions as it translates from research discovery toward commercial application: 1) the state-of-the-art switching circuit is separated from the battery pack without considering system integration and packaging issues; 2) the state-of-the-art individual power switch in the switching circuit has limited condition monitoring and control functions and needs an appropriate electrical insulation and grounding design for real-world applications; 3) the state-of-the-art online state of charge estimation method is an open-loop method subject to problems of wrong initial state of charge and accumulating estimation errors; and 4) the state-of-the-art solution does not offer an efficient online state of health estimation method. These limitations will be addressed in this project by designing 1) a power electronics-based switching circuit as an integrated part of the metal connector grid of the battery cells/modules in a battery pack; 2) a low-cost, high-efficiency power switch with integrated condition monitoring and control functions, an optocoupling-based electrical insulation, and a proper grounding design; 3) an closed-loop online state of charge estimation algorithm; and 4) a maximum capacity degradation estimation-based online state of charge estimation algorithm. In addition, the graduate students involved in this project will receive technology translation experiences through the development of the self-X smart battery prototype.