A team of CSIC researchers developed a prototype 10 kilowatt (kW) vanadium redox flow battery to demonstrate its viability as a large-scale electrical energy storage system, particularly for renewables. This 10 kW prototype (10 kW of power and 20 kWh of energy) makes it possible to store electrical energy for stationary applications, such as energy storage in homes or small businesses.
This technology is the first step towards obtaining a 50 kilowatt battery, which will make it possible to extend the use of this technology to the industrial sector. The prototype was presented today at an event organized at the Institute of Carbochemistry (ICB-CSIC), in Zaragoza, in the presence of the President of the CSIC, Rosa Menéndez, among other authorities. The event, open to the public and businesses, could be followed on Youtube.
This prototype is the result of the work of the Interdisciplinary Thematic Platform PTI TrasnEner+, of the CSIC, and represents a technological bet for the stationary storage of electrical energy on a large scale, with the aim of achieving greater integration of renewable energies, by overcoming their problems of intermittency and accelerating the energy transition. The project is coordinated by Ricardo Santamaría, researcher at the Institute of Carbon Sciences and Technologies (INCAR), and involves the participation of groups from eight CSIC centres: INCAR, LIFTEC (integrated in the ICB), ITQ, IRI, ICB, ICMM, ICMAB and ICTP.
Redox flow batteries are highly flexible devices in which energy is stored in electrolytes, which contain the electroactive vanadium species. These electrolytes are located in external reservoirs and circulate thanks to the action of hydraulic pumps inside the battery cells where the electrochemical oxidation-reduction reactions take place.
Their main advantage is the versatility they offer: the power and energy of the system can be configured independently by increasing the active surface of the electrodes, the number of cells and the volume of electrolyte. They also have a long life cycle that can exceed 20 years, which makes them excellent candidates for stationary and heavy-duty applications where other technologies such as lithium batteries cannot compete, facilitating the penetration of renewable energies on the market. market.
“One of the great advantages of redox flow batteries is that they can be sized in power and capacity to serve storage applications both upstream and downstream of the meter; that is, they can be connected directly to generation plants connected to distribution networks or installed at or near energy consumption centers,” explains Santamaría.
A project developed in a multidisciplinary collaborative environment
This 10 kW module is the first milestone in the project to build a 50 kW battery. The prototype is made up of 4 stacks (stacks of cells) similar to those that will be integrated into the 50 kW battery. The different components of the battery were developed by different CSIC teams. The design of all the elements that make up the battery, the technology of the sealing and closing systems, the manufacturing and assembly processes are the work of the LIFTEC research group led by researcher Félix Barreras. The carbon felts used as electrodes were modified by the INCAR research group to improve their electrochemical properties, while the ITQ group, led by Antonio Chica, took care of the membranes and the electrolyte.
The module also integrates an in-house developed battery and energy management system, based on operating protocols compatible with industrial standards, with which the state of the battery can be known at all times.
Likewise, the research group of the Institute of Robotics and Industrial Computing (IRI), led by Ramón Costa, is collaborating with the LIFTEC group in the design of a telemetry system to operate the battery remotely and control all operating variables. viewed in real time. They are also working on the implementation of techniques for predicting the state of charge and health that allow efficient management of energy flows and the extension of the useful life of the device.
Technology with a wide range of applications
The 10 kW prototype could cover the growing needs for residential self-consumption of energy both in isolated dwellings and in small neighborhood communities, or even for small commercial consumers.
However, the final objective of the project is to validate the 50 kW prototype by connecting it to a renewable energy production plant, such as a solar field. To this end, an intelligent micro-grid has been developed at LIFTEC, consisting of the 10 kW flow battery, a solar field and several programmable loads and sources that allow different consumptions to be simulated.
As Félix Barreras points out, “this installation will allow us to study realistic cases according to market needs, with a modular power architecture that allows the battery to be used in stand-alone mode or connected to the network, either by current alternating current or direct current. “.