STTR Phase II: Ultra-thin Laminar Flywheels for Utility Scale Energy Storage

The broader impact/commercial potential of this Small Business Technology Transfer (STTR) Phase II project is to reduce power infrastructure bottlenecks to the deployment of electric vehicle fast chargers. Typically, it is expensive to install high power electric vehicle fast chargers because of limited power availability or demand charges. A large network of electric vehicle fast chargers would reduce range anxiety among electric vehicle drivers and accelerate the electrification of transportation overall. Energy storage systems can be used to build a “buffer” between low power availability at a site and high-power fast chargers by accumulating and then rapidly discharging energy, but conventional chemical batteries have a limited cycle life which degrades faster in high-power applications. Kinetic batteries (such as those based on flywheels), on the other hand, could enable this without having to be replaced and without hazardous byproducts. Modular, cost-effective “buffers” could be deployed anywhere and everywhere an electric vehicle fast charger is required and where power availability is limited. This STTR Phase II project proposes to fabricate, test, and deploy a pilot 100 kWh / 400 kW modular kinetic battery system into a 350 kW electric vehicle charging station along with commercial partners to validate whether the system can act as a drop-in solution. This project enables high-power, fast electric vehicle charging utilizing the existing, low-power grid connections. This project has three basic objectives: 1) fabricate a kinetic battery module with 100 kWh energy storage capacity and 400 kW power output, 2) conduct a rigorous test of the kinetic battery as part of a high-power electric vehicle charger, and 3) design a high-power, alternating current homopolar motor/generator which can provide damping forces to the rotor passively via its windings. This kinetic battery system implements a passively stable magnetic bearing system which enables larger module sizes (reduces balance of system costs and operating expenses) and can connect to the grid synchronously, eliminating the need for costly power electronics and enabling it to provide grid-stabilizing physical inertia as an ancillary service. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.