Characterisation of a 200 kW/400 kWh Vanadium Redox Flow Battery

Declan Bryans,Léonard Berlouis,Hubert Girault,Véronique Amstutz

doi:10.3390/batteries4040054

Declan Bryans, Léonard Berlouis + Show 2 more

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https://doi.org/10.3390/batteries4040054

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Abstract

The incessant growth in energy demand has resulted in the deployment of renewable energy generators to reduce the impact of fossil fuel dependence. However, these generators often suffer from intermittency and require energy storage when there is over-generation and the subsequent release of this stored energy at high demand. One such energy storage technology that could provide a solution to improving energy management, as well as offering spinning reserve and grid stability, is the redox flow battery (RFB). One such system is the 200 kW/400 kWh vanadium RFB installed in the energy station at Martigny, Switzerland. This RFB utilises the excess energy from renewable generation to support the energy security of the local community, charge electric vehicle batteries, or to provide the power required to an alkaline electrolyser to produce hydrogen as a fuel for use in fuel cell vehicles. In this article, this vanadium RFB is fully characterised in terms of the system and electrochemical energy efficiency, with the focus being placed on areas of internal energy consumption from the regulatory systems and energy losses from self-discharge/side reactions.

Highlights

Redox flow batteries (RFBs) can provide a solution to large scale energy storage, giving a more efficient link between energy production, especially from renewables, and energy demand [1,2,3]
As with all battery systems, it has the advantage of being more flexible and mobile in comparison to non-electrochemical technologies, such as pumped hydro and compressed air storage. The latter large scale energy management technologies are restrained by the suitability of the terrain whereas batteries, such as RFBs, can be readily installed anywhere [6] and provide long duration discharge
The purpose of this work was for the University of Strathclyde, Scotland, to analyse and characterise the 200 kW/400 kWh vanadium RFB (VRFB) and determine its actual capacity, the voltage, coulombic and energy efficiencies, identify and quantify the sources of the energy losses and the self-discharge rate under different scenarios

Summary

Introduction

Redox flow batteries (RFBs) can provide a solution to large scale energy storage, giving a more efficient link between energy production, especially from renewables, and energy demand [1,2,3] This type of battery system presents the advantage of having a lower cost, rapid response and a low level of self-discharge and is considered to have a much safer operation, as compared to other battery systems such as the sodium sulphur and lithium ion batteries [4,5]. As with all battery systems, it has the advantage of being more flexible and mobile in comparison to non-electrochemical technologies, such as pumped hydro and compressed air storage The latter large scale energy management technologies are restrained by the suitability of the terrain whereas batteries, such as RFBs, can be readily installed anywhere [6] and provide long duration discharge. Despite a number of developments, such as that of the mixed acid electrolyte employed in the all-vanadium redox flow battery to yield higher densities [12], these systems still struggle to compete with alternative

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