Vanadium redox flow batteries: a technology review

Abstract

SUMMARYFlow batteries have unique characteristics that make them especially attractive when compared with conventional batteries, such as their ability to decouple rated maximum power from rated energy capacity, as well as their greater design flexibility.The vanadium redox flow batteries (VRFB) seem to have several advantages among the existing types of flow batteries as they use the same material (in liquid form) in both half-cells, eliminating the risk of cross contamination and resulting in electrolytes with a potentially unlimited life.Given their low energy density (when compared with conventional batteries), VRFB are especially suited for large stationary energy storage, situations where volume and weight are not limiting factors. This includes applications such as electrical peak shaving, load levelling, UPS, and in conjunction with renewable energies (e.g. wind and solar).The present work thoroughly reviews the VRFB technology detailing their genesis, the basic operation of the various existing designs and the current and future prospects of their application. The main original contribution of the work was the addressing of a still missing in-depth review and comparison of existing, but dispersed, peer reviewed publications on this technology, with several original and insightful comparison tables, as well as an economic analysis of an application for storing excess energy of a wind farm and sell it during peak demand. The authors have also benefited from their background in electric mobility to carry out original and insightful discussions on the present and future prospects of flow batteries in mobile (e.g. vehicle) and stationary (e.g. fast charging stations) applications related to this field, including a case study.Vanadium redox flow batteries are currently not suitable for most mobile applications, but they are among the technologies which may enable, when mature, the mass adoption of intermittent renewable energy sources which still struggle with stability of supply and lack of flexibility issues

Synthesis and properties of branched sulfonated polyimides for membranes in vanadium redox flow battery application

“…Vanadium permeability (Â10 À7 cm 2 min À1 ) Proton conductivity (Â10 À2 S cm À1 ) Proton selectivity (Â10 4 It is vital for the VRB membrane to have enough mechanical strength to endure the assembly and operation processes. Herein, the mechanical performance was evaluated and experimental data are showed in Fig.…”

“…Therefore, large-scale energy storage devices are required to provide stable and reliable electricity in coherent with current power grids. As a most potential energy storage device, vanadium redox flow battery (VRB) [1][2][3] has been drawn increasing attention due to its flexible design, long use cycle, high efficiency and high safety [4,5]. Besides, the VRB is of great importance since it is capable of storing large quantities of electricity (multimegawatt-hours, (MWhs)) obtained from intermittent renewable sources for the power grid with a simple design [6,7].…”

Energy cycle based on a high specific energy aqueous flow battery and its potential use for fully electric vehicles and for direct solar-to-chemical energy conversion

“…Both reactions (12) and (13) occur in parallel in the intermediate 4≤pH≤8 range where the formal secondorder rate constant is the highest [59]. Thus, the optimal pH for the regeneration process…”

“…Another advantage of flow batteries compared to low-temperature fuel cells is a possibility of the elimination (or of a significant reduction of the amount) of expensive platinoid electrocatalyst(s) since the slow electroreduction of O 2 is replaced by a more reversible electrochemical process. Conventional redox flow batteries (such as all-vanadium, iron-chromium) have low power densities (typically, <0.2 W/cm 2 ) [10][11][12][13][14][15][16][17][18] which results in the cost of power being too high for stationary energy storage. The recent surge of interest in hydrogen-bromine flow batteries, [19] for which an areal power of 1.4 W cm 2 has been demonstrated [20], gives hopes that flow batteries may finally find acceptance in stationary energy storage.…”

Energy storage systems: power grid and energy market use cases

“…System development can also contribute to spreading storage systems better. The use of standardized modules cuts manufacturing and sales costs substantially [46]. This necessitates in-depth technical and economic analysis of applications to define standard battery sizes, e.g.…”