Page 43 - European Energy Innovation - autumn 2018 publication

Autumn 2018 European Energy Innovation
In addition, these compounds can
be toxic and are not environmentally
benign. Consequently, there has been
a steady increase in research on
organic active materials for batteries
over the last couple of years.
At present, the only available
commercial Redox-Flow Batteries
(RFBs) technology is the vanadium
RFB, which uses vanadium salts
as active materials that are then
dissolved in concentrated sulfuric
acid. These solutions, the so-called
electrolytes (anolyte and catholyte)
are stored in two separate tanks. For
charge and discharge of the RFB,
the electrolytes are pumped into an
electrochemical cell consisting of two
electrodes separated by a membrane
(cell stack) where the redox reactions
are taking place. The great advantage
of RFBs is that the power (i.e. the size Wetsus, European Centre of
of the membrane/cell stack) and the
energy (i.e. the size of the storage
tank) can be scaled independently.
However, the main drawbacks of
the existing commercial V-RFBs are
the high cost of the active material
vanadium which is a critical raw
material.
To address this, CEEC Jena has
developed a salt water-based
polymer to replace vanadium in RFBs.
As membranes are then cheaper, the
polymer RFBs cost significantly less
while also being more sustainable
and easy to handle. The polymers
(macromolecules) can be charged /
discharged (oxidized and reduced).
The macromolecules are larger in size
compared to the sodium and chloride
ions opening up the possibility to
utilize size-exclusion membranes (i.e.
dialysis membrane).
The possible application areas for
polymer RFBs are similar to other
flow battery technologies providing
many opportunities for applications
of different sizes. As an example,
CEEC Jena are currently working
together on the project brine4power
with EWE, a large German electricity
producer and provider, where this
www.europeanenergyinnovation.eu
43
BATTERY INNOVATION
H O + NaCl H O + NaCl
2
HO
It is safe as it has no fire or explosion
Blue Battery hazard, and it can be built on every
scale (kWh-MWh-GWh) as well as
new and pioneering metal free RFB without geographical constraints.
will be used to operate salt caverns The Blue Battery has a very distinct
for energy storage, essentially advantage in that the energy storage
creating the world’s largest battery to capacity is very cheap (basically salt
store green electricity. water and a reservoir). This means
that by adding additional reservoir
THE BLUE BATTERY volume, the energy storage capacity
Within AquaBattery – a Netherlands- is increased. This characteristic
based spin-off company from allows to charge and discharge the
battery for longer periods of time.
Excellence for Sustainable Water Therefore, discharge times of multiple
Technology – a team of eight young hours to weeks are possible with the
engineers and entrepreneurs are Blue Battery which really sets this
collaborating on the development of technology apart from other storage
a novel stationary electrical energy systems.
storage system: the Blue Battery.
This Blue Battery stores electricity in AquaBattery and its partners are
water and table salt. Electrical energy testing the first household-scale
is used to separate fresh water (1kW-10kWh) Blue Battery at The Green
from salt water during the charging Village in Delft. Different components,
phase, and with the same technology such as membrane stacks, water
electrical energy is regenerated when tanks, and pumps are upscaled and
fresh water and salt water are mixed integrated for the first time and they
during the discharging phase. are operated autonomously on a
smart battery management system.
The unique selling points of the The aim is to showcase the potential
Blue Battery compared to other of the Blue Battery in a controllable
stationary energy storage systems are but realistic environment, and to
its sustainability, availability, safety, obtain valuable insights of how it
and scalability. Unlike most other functions within an electricity grid and
grid scale electrical energy storage
systems, the Blue Battery does not
contain any toxic or scarce materials.