High Volume Flow Battery Systems

Unlike secondary battery systems using solid active materials, flow batteries decouple energy storage (i.e., the concentration of electrolyte and storage container size) and power conversion (i.e., the central electrochemical reaction energy conversion device), thus enabling relatively safe energy storage and long battery life (4, 6 – 8).

With respect to redox-targeting methods that only circulate redox mediators, several flow batteries using this concept have demonstrated unprecedentedly high volumetric energy densities (∼ 500–670 Wh l −1; calculated from the density of the active materials) 72, 82, which are comparable to those in conventional LIBs.

Here, we introduce a submillimeter bundled microtubular (SBMT) flow battery cell configuration that significantly improves volumetric power density by reducing the membrane-to-membrane distance by almost 100 times and eliminating the bulky flow distributors completely.

Flow batteries are a promising energy storage solution. However, the footprint and capital cost need further reduction for flow batteries to be commercially viable. The flow cell, where electron exchange takes place, is a central component of flow batteries.

There are several advantages of this design, enabling an order of magnitude increase in volumetric power density compared with the conventional planar cell configuration. First, all the flow battery parts are in a submillimeter size, which is significantly smaller than those used in a planar or the centimeter- and millimeter-scale tubular cells.

Aqueous flow batteries can provide a rapid response time and good flowability of the catholytes and anolytes with minimum pump loss, thus facilitating the storage of the generated energy.