Redox Flow Batteries

Detailed overview of innovation with sample startups and prominent university research


What it is

Redox flow batteries are a type of rechargeable battery technology that stores energy in liquid electrolytes containing redox-active species. These electrolytes are pumped through an electrochemical cell, where the redox reactions occur, generating an electric current during discharge and vice versa during charging. Redox flow batteries are known for their scalability, long lifespan, and inherent safety, making them suitable for grid-scale energy storage and other applications requiring long-duration storage and high power output.

Impact on climate action

Redox Flow Batteries in the Battery Storage domain bolster climate action by enhancing renewable energy integration and grid stability. By storing excess energy from intermittent sources like wind and solar, these batteries optimize energy use, reduce reliance on fossil fuels, and accelerate the transition to a low-carbon energy system, mitigating climate change impacts.

Underlying
Technology

  • Liquid Electrolytes: Redox flow batteries store energy in liquid electrolytes, typically containing metal ions or organic molecules, that can undergo reversible oxidation and reduction reactions.
  • Electrochemical Cell: The electrochemical cell consists of two electrodes separated by a membrane. The electrolytes flow through the cell, and the redox reactions at the electrodes generate an electric current.
  • External Tanks: The electrolytes are stored in external tanks, allowing for independent scaling of energy capacity and power output. This makes redox flow batteries highly scalable and adaptable to different energy storage needs.
  • Pump and Flow System: A pump and flow system circulates the electrolytes through the electrochemical cell, ensuring efficient energy conversion.

TRL : 6-8 (depending on the specific electrolyte chemistry)

Prominent Innovation themes

  • New Electrolyte Chemistries: Researchers are developing new electrolyte chemistries with higher energy densities, improved stability, and lower costs. This includes exploring the use of vanadium, zinc-bromine, iron-chromium, and other redox-active species.
  • Advanced Membrane Materials: Innovations in membrane materials are improving the selectivity and durability of membranes, enhancing battery performance and lifespan.
  • System Design and Optimization: Researchers and startups are developing innovative system designs for redox flow batteries, focusing on improving efficiency, reducing costs, and increasing scalability.
  • Hybrid Flow Battery Systems: Hybrid flow battery systems combine different electrolyte chemistries to optimize performance and cost for specific applications.

Other Innovation Subthemes

  • Electrolyte Innovations
  • Membrane Advancements
  • System Optimization Techniques
  • Hybrid Battery Configurations
  • Scalability Solutions
  • Energy Density Enhancements
  • Durability Improvements
  • Efficiency Enhancements
  • Novel Electrolyte Chemistries
  • Advanced Membrane Materials
  • System Design Innovations
  • Performance Optimization Methods
  • Integration with Renewable Energy
  • Smart Grid Applications
  • Redox-Active Polymer Research
  • Control Strategy Developments
  • Commercial-Scale Implementations

Sample Global Startups and Companies

  1. ESS Inc.:
    • Technology Enhancement: ESS Inc. specializes in iron flow battery technology for energy storage applications. Their flow batteries use iron-based electrolytes to store and release energy, offering long-duration storage capabilities suitable for grid-scale applications. ESS Inc.’s flow batteries are known for their high efficiency, scalability, and safety features.
    • Uniqueness of the Startup: ESS Inc. stands out for its focus on iron flow battery technology and its commitment to providing reliable and cost-effective energy storage solutions. Their flow batteries offer advantages such as long cycle life, rapid response times, and minimal degradation over time, making them ideal for applications requiring daily cycling and extended duration storage.
    • End-User Segments Addressing: ESS Inc. serves utilities, renewable energy developers, and commercial customers seeking grid-scale energy storage solutions. Their flow batteries are deployed in renewable energy integration projects, microgrids, and grid stabilization applications, enabling the integration of renewable energy sources and improving grid reliability.
  2. Invinity Energy Systems:
    • Technology Enhancement: Invinity Energy Systems specializes in vanadium flow battery technology for long-duration energy storage. Their flow batteries use vanadium-based electrolytes to store and release energy, providing a scalable and durable solution for grid-scale applications. Invinity’s flow batteries are designed for high energy density, long cycle life, and low maintenance requirements.
    • Uniqueness of the Startup: Invinity Energy Systems stands out for its expertise in vanadium flow battery technology and its focus on delivering reliable and sustainable energy storage solutions. Their flow batteries offer advantages such as wide temperature tolerance, rapid response times, and deep discharge capabilities, making them suitable for a wide range of grid and off-grid applications.
    • End-User Segments Addressing: Invinity Energy Systems serves utilities, commercial and industrial customers, and remote communities seeking reliable and long-duration energy storage solutions. Their flow batteries are deployed in renewable energy projects, microgrids, and utility-scale energy storage systems, providing grid stability, backup power, and energy resiliency.
  3. Primus Power:
    • Technology Enhancement: Primus Power specializes in zinc-bromide flow battery technology for grid-scale energy storage applications. Their flow batteries use zinc-bromide electrolytes to store and release energy, offering high efficiency, reliability, and safety. Primus Power’s flow batteries are designed for rapid response times, long cycle life, and scalable deployment.
    • Uniqueness of the Startup: Primus Power stands out for its focus on zinc-bromide flow battery technology and its track record of successful deployments in grid-scale projects. Their flow batteries offer advantages such as high energy density, low cost per kilowatt-hour, and minimal environmental impact, making them suitable for large-scale energy storage applications.
    • End-User Segments Addressing: Primus Power serves utilities, renewable energy developers, and commercial customers seeking cost-effective and scalable energy storage solutions. Their flow batteries are deployed in grid stabilization projects, renewable energy integration, and microgrid applications, enabling the transition to a more sustainable and resilient energy infrastructure.

Sample Research At Top-Tier Universities

  1. Massachusetts Institute of Technology (MIT):
    • Research Focus: MIT is a frontrunner in research on Redox Flow Batteries, focusing on developing advanced materials, electrolytes, and system architectures to enhance the performance, efficiency, and scalability of redox flow battery technologies.
    • Uniqueness: Their research involves the design and synthesis of novel redox-active species, membranes, and electrodes for improving energy density, cycling stability, and cost-effectiveness of flow battery systems. They also explore flow cell design optimization, flow management strategies, and system integration techniques to enable grid-scale energy storage applications.
    • End-use Applications: The outcomes of their work have applications in renewable energy integration, grid stabilization, and electric vehicle charging infrastructure. By advancing redox flow battery technology, MIT’s research contributes to enhancing grid reliability, supporting intermittent renewables, and enabling the transition to a clean and resilient energy infrastructure.
  2. Stanford University:
    • Research Focus: Stanford University conducts innovative research on Redox Flow Batteries, leveraging its expertise in electrochemistry, materials science, and systems engineering to develop next-generation flow battery technologies with improved performance and durability.
    • Uniqueness: Their research encompasses the development of high-energy-density redox couples, selective membranes, and flow cell components tailored for specific applications and operating conditions. They also explore advanced manufacturing techniques, electrode architecture optimization, and in situ diagnostics for characterizing and improving battery performance.
    • End-use Applications: The outcomes of their work find applications in stationary energy storage, microgrid deployment, and industrial process optimization. By pushing the boundaries of redox flow battery technology, Stanford’s research contributes to addressing key challenges in energy storage, enhancing grid resilience, and enabling the integration of renewable energy resources.
  3. University of California, San Diego (UCSD):
    • Research Focus: UCSD is engaged in cutting-edge research on Redox Flow Batteries, leveraging its expertise in chemical engineering, electrochemical systems, and energy storage technologies to develop innovative solutions for grid-scale energy storage and electrification applications.
    • Uniqueness: Their research involves the design, synthesis, and characterization of redox-active organic molecules, metal complexes, and hybrid electrolytes for improving energy efficiency, safety, and environmental sustainability of flow battery systems. They also explore novel flow cell architectures, operating strategies, and grid integration schemes to address performance limitations and market barriers.
    • End-use Applications: The outcomes of their work have applications in renewable energy integration, peak shaving, and demand response. By advancing redox flow battery technology, UCSD’s research supports the transition to a low-carbon energy system, enhances grid stability, and promotes the widespread adoption of renewable energy technologies.

commercial_img Commercial Implementation

Redox flow batteries are being implemented in commercial-scale projects around the world, primarily for grid-scale energy storage applications. For example, Invinity Energy Systems has deployed vanadium flow batteries in projects ranging from grid-scale energy storage to off-grid power systems.