A flow battery cell testing facility for versatile active material characterization: Features and operations

Technological development plays a fundamental role in view of the successful realization of large Flow Battery (FB) systems. This work firstly presents the design, construction and commissioning of FB-Cell Testing Facility (FB-CTF), a bench for testing electrolytes, electrodes, membrane and cell configurations under controlled conditions. Several construction aspects related to the hydraulic system, power conditioning system, and flow battery management system are described in detail. FB-CTF has been conceived and built to accurately measure the main thermal, hydraulic, electric, and energy quantities which define the performance of FBs. A comprehensive experimental campaign has been carried out on FB-CTF to characterize some widely used electrodes and membranes for Vanadium FBs (VFBs), produced by some major manufacturers. The paper presents the developed testing protocols and the test results, specifically focusing on electrical and hydraulic characterization. In addition, a methodology using FB-CTF data in the prediction of the electric and hydraulic performance of large stacks is proposed. More generally, FB-CTF measurements can be used to address the design of industrial-scale FBs. FB-CTF can provide insights for the design of large flow battery systems, to help bridge the gap between academic research and industry.