Advanced Vanadium Compact Flow Batteries for Renewable Integration

Z.G. Yang
UniEnergy Technologies, LLC, US

Keywords: energy storage, battery

Summary:

Vanadium redox flow batteries (VRFB’s) store electricity in aqueous electrolytes and discharge it when needed by flowing the liquid electrolytes through battery stacks. Unlike conventional batteries, VRFB’s allow the full separation of power (KW) and energy (kWh) and offer intrinsic advantages such as safety. With vanadium species as “active” elements on both positive and negative sides, VRFB’s have been demonstrated to have virtually unlimited cycle life for both shallow and deep cycles. However, traditional VRFB’s are still limited in their electrolyte energy density, power capability and operating temperature range, among other issues. They are thus challenged to meet performance and economic requirements. To address these issues and meet these requirements, UniEnergy Technologies, LLC (UET) is commercializing an Advanced Vanadium Compact Flow Battery (AV-CFB) that utilizes sulfate and chloride mixed acid electrolytes initially developed and patented at Pacific Northwest National Lab under support of the DOE-OE Storage Program. (The effort has just won the Federal Laboratory Consortium’s (FLC) Excellence in Technology Transfer Award.) UET’s AV-CFB has been proved to practically double energy density, over double power capability and operate over a much greater temperature range, improving their performance and operational flexibility over conventional VFRB’s and making them desirable storage technologies for renewable integration. This paper will discuss the new generation VRFB and the UET’ AV-CFB system that enables in an all-in-one configuration for renewable smoothing, firming, and time-shifting.