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Overview of Redflow’s unique zinc-bromine flow battery energy storage technology

Redflow is an Australian company that has developed ZCell and ZBM2, small flow batteries which tolerate daily hard work in harsh conditions. Redflow Limited is a public company listed on the Australian Securities Exchange (ASX: RFX). Redflow’s unique flow batteries are designed for stationary energy storage applications, including its ZCell home battery and its scalable ZBM2 batteries for telecommunications, commercial & industrial and grid-scale deployment. Redflow’s head office and core battery R&D facilities are in Brisbane while its global sales and ZCell residential battery operations, including its deployment lab, are located in Adelaide.

What makes Redflow batteries unique?

Redflow’s zinc-bromine flow batteries possess unique technical attributes that ideally suit them for time-shifting energy on a daily, full-cycle basis as well as providing emergency power supplies in a wide range of climates. Redflow batteries can charge and discharge 100 per cent of their energy capacity each day, avoiding the damage such performance causes traditional battery chemistries. Redflow batteries can also maintain their nominal 10 kilowatt-hour (kWh) storage capacity throughout their operating life – unlike lithium-based and lead-acid batteries which lose energy storage capacity with use. Redflow backs ZBM2 with a 10-year warranty (see full warranty for details).

Redflow batteries can also operate at ambient temperatures as warm as 50 degrees Celsius (122 degrees Fahrenheit) without any external active cooling, provided that sufficient airflow is available for the battery to cool itself. High-temperature operation do not affect the expected battery life. Unlike lithium-based batteries, the flow battery is not at risk of ‘thermal runaway’ –  industry jargon for ‘bursting into flames!’ – as the zinc bromide electrolyte is an intrinsically non-flammable material. Also, Redflow batteries are made from materials that are easy to recycle or reuse.

Another Redflow benefit is that its zinc-bromine flow batteries can be left in any state of charge – from full to fully discharged – indefinitely without damage.  Please contact Redflow for further details on this option.  

How do zinc-bromine flow batteries work?

Redflow’s Australian-developed zinc-bromine flow battery is a type of hybrid flow battery, which contains an electrolyte comprised of a solution of zinc bromide salt dissolved in water. This electrolyte is stored in two tanks, with one tank storing the electrolyte for positive electrode reactions and the other for the negative. Upon the application of an external voltage, when the solution is pumped from the tanks through the battery’s electrode stack, metallic zinc is plated from the electrolyte onto the negative electrode surfaces in the cell stacks. Bromide is converted to bromine at the positive electrode surface and is stored in a safe, liquid phase in the electrolyte tank. On discharge, the reverse process occurs, with the metallic zinc plated on the negative electrodes dissolving in the electrolyte. This makes it available to be plated again at the next charge cycle, in a process that causes no degradation of storage capacity over time. Redflow batteries can be left fully discharged indefinitely without damage and also sustain their nominal energy storage capacity for 10 years.

Where are Redflow batteries made?

Redflow manufactures its ZBM2 zinc-bromine flow batteries at a purpose-designed factory in Thailand, which is operated by long-term manufacturing partner MPTS. The ZCell battery enclosure – which contains a ZBM2 battery in a weatherproof case – is designed and manufactured in Adelaide.

Where can I buy Redflow batteries?

Redflow’s high energy density ZBM2 batteries are sold, installed and maintained by a global network of system integrators  Redflow’s ZCell batteries are sold by an Australia-wide network of approved installers

Where can I learn more about Redflow?

Redflow website

ZCell website

Redflow press releases:

For media assistance, contact John Harris on +61 8 8431 4000 or email

Click here to view photo galleries from which you can download high-resolution images of Redflow batteries, installed sites, management and board members.

More about Redflow ZBM2 and ZCell customers

Customer case study: (South Africa): Mossel Bay Municipality department goes carbon neutral with Redflow

Customer case study: (South Africa) Bosco Printed Circuits – A ZBM2 case study in complex energy system optimisation

Customer case study: (Adelaide) Hackett house powers through SA blackout

Customer case study: Redflow telco BTS case study from Latin America

Customer case study (Queensland): Queensland family sets ZCell residential record

Customer case study (Victoria): Adrian lives the off-grid dream with ZCell

Customer case study (South Australia): Alan Noble fires up ZCell for bushfire defences

Customer case study (South Australia): Conservation SA showcases ZCell