REDFLOW ZINC-BROMIDE MODULE
(ZBM )FOR DC APPLICATIONS
Energy Storage for Communities, Mining and
Telecommunications – Case studies
Mike Giulianini, PhD
CTO, Redflow Limited
Redflow Product
Source: Google search ‘Flow Batteries’ Option: Photo
Redox Flow Battery replacement for existing
lead acid systems
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48V and 170Ah, 200Ah or 200Ah (@53V)
100% DoD
Up to 50°C with no ageing effect
Water based and inherently safe
BMS integrated
CE approved
Recent Timeline (related to DC applications)
01/2014
New electrode shows
unprecedented life
estimation in advanced
degradation test
04/2014
First ‘full-DC’ ZBM
equipped with Module
Management System
assembled
03/2014
First ZBMs built with the
new electrode for
characterisation in the
long time test facility
12/2014
DC ZBM CE compliant and
declared inherently safe by
independent body.
Results available for the
Hibernation Mode
06/2014
ZBM production
successfully outsourced to
Flextronics
04/2014
ZBM2, ZBM3 products
launched with 2,000 cycles
100% DoD warranty
All the ZBMs in test since 3/2014 are cycling daily with no sign of degradation (several MWh processed per ZBM)
Test of the Module @48V not the single cell!
ZBM Key aspects
• 3/5 kW, up to 11kWh energy out;
• Long shelf life either charged or
discharged;
• Designed for long life applications;
• At the end of life the battery can be
100% regenerated at a fraction of the
price;
• Almost entirely made of plastic;
• Large-scale production is expected to
drive the price reduction constantly
over the coming years;
Redflow in the World
Base Telecommunication Station Site
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Telco site, approximately 1.8kW load;
Frequent grid blackouts 3-5h;
Backup needed 4h;
Existing LA capacity 400Ah Nom (20kWh Nom);
Replacement period 1 or 2 years;
Results
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A total of 29 blackout events were recorded in the last 143 days (one every 5 days approximately);
The ZBMs provided a total of 2807Ah or more than 140kWh (and 100Ah or 5kWh per event on
average);
6 events were longer than 4h 30m or 270m which accounts for more than 160Ah per event
Several events featured temperatures above 40 degrees and ended with the ZBM fully discharged.
The same events with the existing batteries would have resulted in a fast aging processes;
Results
Projecting the experimental data back to the beginning of the trial brings the
following:
• A total of 37 blackout events would have happened in the last 183 days
(one every 5 days);
• The ZBMs would have provided a total of 3592Ah or 180kWh;
• The total usage of the ZBM up to date is 37 cycles which corresponds to 74
cycles per year;
• Therefore the ZBM life expectancy in this application is well over 20 years.
Added value
The ZBM solution eliminates the following costs related to the existing solution (LA):
• Elimination of the existing cost to replace lead acid batteries every year
which includes:
• Battery costs;
• Installation costs;
• Disposal costs;
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Eliminates service down costs and loss of revenues;
Payback period expected to be very short;
Creates an advantage over the competitors;
Customer service and perception is improved as communications are
available during blackouts and possible emergency situations;
• Potential marketing opportunity.
110V DC system in Power plant
The customer contacted Redflow about a backup application with the following specification:
• DC bus nominal voltage
110V DC;
• Normally floating voltage
125V DC;
• Load current
12A;
• Backup time
5 hours;
• Needed backup time
12 hours;
• Available space
8.5 m2;
Redflow solution:
• Deployment of 3 ZBM for a total of 510 Ah;
• Resulting footprint of less than 3 m2;
• Resulting backup time of more than 12 hours;
Results
The system @48V
guarantees same
performance as in the
lab
Hibernation Mode
• Designed for UPS and backup applications targeting extremely long
life;
• Charge (up to 120%) – Prepare – Stop (pumps off);
• When a loss of power occurs the battery wakes up and perform a full
cycle (in the worst case scenario);
• The main advantage is that the battery is OFF most of the time
without any degradation (pumps or electrodes);
• If the site experiences 100 blackouts a year, the battery projected life
exceeds 20 years (2,000 cycles)
Hibernation Mode
• The hibernation consumption is a few mA;
• The ZBM charge is inhibited but the battery is able to
supply instantaneously up to 10Ah (@50V and
available for months);
• To improve reliability and response
time we coupled the ZBM with
a Supercapacitor (120F / 64V);
Hibernation Mode Test
• Even if the ZBM is at 0V it
restarts in 20/25s;
• The Supercap can supply
1.5kW for over a minute (3kW
for 30s);
• The system will be always able
to tackle a blackout and
backup the site for over 6h
per ZBM;
• There is no limit to the
number of ZBMs that can be
connected in parallel;
Hibernation Mode Business Case
• Valid alternative tho the existing system (LA + DG) considering:
– DG restart issues;
– DG maintenance;
– LA maintenance (assessment, replacement, disposal);
– Non-modular solution;
– Non ideal for intermediate duration blackouts;
• Supercaps have certified 1M cycles and guaranteed no-loss of
Capacitance over 10 years @VR;
• Both devices (ZBM and Supercaps) are tolerant to high temperatures
up to 50°C so no need for environment conditioning.
Other ZBM applications
• Large scale and microgrids;
• AC application: Residential and Industrial;
• Integration with Renewables;
Please Enquire Us!
Thank you!