 |
|
|
 |
| |
Will it do the job? Could it be made at a cost that people would
pay? Research shows that my idea is sound, but technical development
is needed to prove that a product is possible
|
|
|
|
| |
Scientists,
engineers, technicians and tradespeople examine ways to
make sure the idea works. They might try using a few different
materials before they find the best one. They might develop
new materials or new processes to make the product. They
certainly have to work out how to make it.
They might test prototypes under different conditions,
such as at a range of temperatures. They might run them for many hours
to simulate normal use over many months. They might even test them to
destruction.
A product must do the job for which it is sold, or customers
won't buy it or will demand their money back. Many products must meet
standards set by governments. They should be safe to use. Ideally, parts
should be reusable or their materials recyclable at the end of a product's
useful life.
Technical development is often thought of as tied to research,
and the activity is called research and development (R&D). It is indeed
often the same team that works on both, but different skills and approaches
are needed.
Technical development is expensive. It is not much use
doing it if nobody is going to want the product. The developer
is often convinced that it will sell, but investors will
be attracted to back the project only if potential buyers
have shown interest. The technical people might work with
designers and market researchers to make design models
and prototypes and test customers' reactions to them.
Pharmaceutical development http://www.merckfrosst.ca/e/research/r_d/pharmaceutical_r_d.html
Engine testing during development http://www.orbeng.com.au/orbital/engineeringServices/testingValidation.htm
|
|
|
| |
The
vanadium battery — a technical development saga
We need to store electricity for one of two reasons: we
don't want to use it at the same time as we generate it;
or we want to use it to power a vehicle or a portable
device. Many different types of battery have been developed
for these purposes, but all have their drawbacks. One
important problem with rechargeable batteries is poor
efficiency – less electricity can be drawn from them
than is used to charge them.
In 1984 at the University of NSW, Dr Maria Skyllas-Kazacos
began to research the possibility of using solutions of
vanadium (a metallic element) to store electricity. Her
aim was to develop a new battery.
The research soon showed promise, but the development
of the battery took many years – and a huge amount
of human energy. The R&D team persisted because their
tests showed the battery could be very efficient and could
have a variety of applications.
The developers tested a wide range of membrane and electrode
materials and developed a new type of conducting plastic.
They designed some components of the battery and selected
others. They tested different ways of assembling the components.
After years of refining the components, and making and
testing batteries, the patented technology was licensed
to several companies. The first to license the battery
was Mitsubishi Chemical Corporation and its subsidiary,
Kashima-Kita Electric Power Corporation. They developed
large batteries for use in load levelling: storing electricity
generated in times of low demand and releasing it for
use in times of high demand. The vanadium battery could
also be used to store solar or wind energy, which are
not generated continuously, and in vehicles, if charged
vanadium solutions could be obtained from service stations.
The vanadium battery is now being manufactured in Japan
by Sumitomo Electric Industries and is being exported
around the world.
|
|
|
|
| |
 |
Battery in lab.
Courtesy of Maria Skyllas-Kazacos |
 |
| Diagram of a single cell. |
|
|
Introduction
How the vanadium battery works
A battery is an energy storage device made up of several
electrochemical cells. Reversible chemical reactions take
place in each cell: the changes that occur while it is
being charged are reversed during discharge, when the
battery is being used to supply electricity.
The vanadium battery is different to most other batteries,
in that energy is stored externally in tanks of liquid
(the electrolyte). The electrolyte is made of vanadium
sulphate dissolved in acid.
When the battery is fully charged, one tank contains V(V)
in solution, and the other tank contains V(II). The V
represents vanadium and the Roman numeral in brackets
represents its oxidation state. Another way of representing
these vanadium ions is V5+ (that is, a vanadium atom that
has lost 5 electrons) and V2+. To fully charge the battery,
electricity must be supplied from an external source.
This drives the following reactions in which e represents
an electron.
Charge: V(IV) - e -> V(V) and V(III) + e -> V(II)
During discharge, the electrolytes are pumped through
the battery and interact with each other across a membrane.
Electricity (a flow of electrons) is produced as each
V(V) ion gains an electron and each V(II) ion loses an
electron.
Discharge: V(V) + e -> V(IV) and V(II) - e -> V(III)
The electrons are collected at an electrode in each cell.
All the electrodes in the battery are connected to an
external circuit so the electricity produced can be put
to use.
For a detailed explanation, go to www.ceic.unsw.edu.au/centers/vrb/ and select Publications: Recent progress.
Before the innovation
Lead-acid batteries were first made in the 1860s and are
still the main type of battery for cars, solar energy
storage, load levelling back-up power supply for industry
and commerce. Their efficiency (energy output divided
by energy input) varies between 55% and 90% and they need
to be replaced every few years.
The first experimental 'redox flow' battery was made by
NASA (the US space agency) in 1974. A major drawback of
this battery was that it used solutions of two metals,
iron and chromium, and that some iron leaked into the
chromium solution, and vice-versa. Some Japanese companies
built similar batteries under licence to NASA, but could
not improve their low output voltage and low efficiency;
and the low concentration of iron and chromium in solution
meant that these batteries could not store much energy.
A patent issued in 1976 to an Italian group mentioned
vanadium in a list of other metals that could be used
in redox batteries, but the patent could not have led
to a workable battery as no detail was known about the
particular ions or solutions that would be needed.
Seeing the opportunity
Energy storage is important in many situations. Solar
energy systems usually include batteries to store energy
for use after dark.
In the early 1980s, Dr Maria Skyllas-Kazacos was a young
lecturer at UNSW, where she had trained in chemical engineering
and industrial chemistry. Her research field was electrochemistry
(the interaction between electricity and chemistry). She
had done some research at Bell Laboratories in the USA
that involved working with solutions of vanadium and measuring
their electrical properties, to see if they were suitable
for use in solar cells.
Also at UNSW, Dr Martin Green (later a world leader in solar
research was doing research into solar cells. He suggested
the NASA iron-chromium battery as a project for one of
his research students, and the student asked Maria to
become his co-supervisor.
Maria searched scientific journals for information about
redox batteries. She saw that there was an opportunity
to overcome the iron-chromium contamination problem by
using just one element that can exist in four different
oxidation states. She decided to try vanadium first, because
both she and a colleague (Professor Bob Robins) had experience
with its chemistry.
|
|
|
| |
 |
Team with buggy.
Courtesy of Maria Skyllas-Kazacos |
 |
Dr Maria Skyllas-Kazacos with
battery.
Courtesy of Maria Skyllas-Kazacos |
|
|
Time
and money
With development, you've got targets. You
have to meet the targets. That's the really challenging
thing.
Professor Maria Skyllas-Kazacos
A target might be: to prove that your concept works efficiently;
to build a prototype; to show that your prototype can
keep running under different conditions; or to reduce
the cost of making the product.
As well as setting targets, funding bodies set deadlines
for reports. And postgraduate students (who do a lot of
Australia's R&D) are expected to complete and write
up their work by a set date.
In 1983, Maria wrote a proposal for a Federal Government
energy research grant, but this was not successful. So
she did some initial experiments during the summer holiday.
She then supervised research by honours student Elaine
Sum, who carried out more thorough experiments. These
showed that solutions of vanadium in sulphuric acid could
be charged with electricity and later discharged: a vanadium
redox battery was technically possible.
Based on these preliminary 'proof-of-concept' results,
Maria applied again for energy research funding in 1984.
This time she did receive a grant.
There was much work still to be done to develop a useful
battery: optimising the electrolyte, selecting materials,
and designing cells to achieve adequate energy density
(energy stored per unit volume), high energy efficiency
(ratio of energy output to energy input) and long life.
Obtaining further grants over the life of the project
depended on progress being made towards a commercially
viable product. Like many team leaders, Maria spent many
sleepless nights worrying about how to keep her researchers
employed and maintain continuity in the research. She
wrote several very detailed proposals to both Federal
and NSW Government funding bodies and obtained a series
of grants. She also obtained funds from several companies
over the life of the project, in return for licences to
make and sell her patented technology.
|
|
|
| |
|
|
The first patent
The first grant was for optimising the electrolyte and
cell design so that practical systems could be built and
tested. Maria employed chemical engineer Dr Miron Rychcik
to design and test simple cells containing vanadium solutions
separated by a membrane.
Elaine Sum had used vanadium oxide as her raw material.
The oxide is so insoluble that she could prepare only
very dilute solutions, so that the energy density of her
cells was very low. Maria hypothesised that the more soluble
vanadyl (IV) sulphate would be a better raw material and
that it could be oxidised electrochemically to produce
a more concentrated solution of V(V).
Miron confirmed this hypothesis and found that the resulting
V(V) solution was relatively stable. Thus it was possible
to increase the concentration of vanadium in solution,
and hence the energy density, tenfold.
Other students at UNSW studied the NASA redox flow battery
patent and related articles. They found that NASA had
investigated the use of vanadium but, finding its compounds
to have low solubility, rejected it in favour of the iron-chromium
combination. The team used the published designs to make
a small flow cell, but the drawings lacked detail and
internal leaks were a serious problem.
It took many months to find an arrangement of parts and
materials that worked. Fitting the parts together was
not easy, nor was holding them in place. Both glue and
bolts were needed to solve the leakage problem, and rigidity
was ensured by using metal end plates.
Maria filed the basic vanadium battery patent in 1986,
jointly with Professor Bob Robins, who had encouraged
her to make her second grant application. He also provided
expertise in vanadium chemistry.
There was, however, still much to be done to produce a
commercial battery. In 1987 Agnew Clough Ltd, an Australian
company with vanadium mining interests, bought worldwide
exclusive rights to the technology.
At the same time Michael Kazacos (Maria's husband), who
had trained in analytical chemistry and toxicology, joined
the team. He was to become a key player, managing the
laboratory and negotiating with suppliers, as well as
carrying out R&D work and maintaining continuity as
researchers joined the team and moved on. This is a significant
problem in academic R&D, as students often leave when
they finish their degrees and other researchers leave
when grants run out.
|
|
|
| |
|
|
Battery
components
Electrolyte
When the patent was filed, the price of vanadium sulphate
was $800/kg. Sir Agnew Clough advised Maria to develop
a method for dissolving vanadium pentoxide, which cost
around $8/kg. However, as Elaine Sum had confirmed, it
is very insoluble.
Rod McDermott, a schoolteacher, wanted a casual position
on the project. He set to work on this problem, first
trying electrolysis: he passed an electric current through
a suspension of vanadium pentoxide powder in acid, to
continuously reduce and dissolve small amounts of the
oxide. In other words, he used the electric current to
change the V(V) in V2O5 to the more soluble V(IV). This
approach worked, as did using chemical reductants such
as oxalic acid instead of electrolysis.
An important aspect of the development process is scaling
up, getting the same things to work at a large scale suitable
for industry as on a small, laboratory scale. The methods
that used powder suspended in acid would be very hard
to scale up, as the suspension would need to be stirred
and the powder could clog up the apparatus.
A student began to investigate vanadium chemistry in more
detail. This research led to improved understanding of
the complexity of vanadium chemistry – and it led
to a process for making solutions at a cost of a few dollars
per kg. The team later found an even better way to make
the electrolyte.
It's a story of continued development and evolution
of the process.
Professor Maria Skyllas-Kazacos.
|
|
|
| |
 |
Electrode.
Courtesy of Maria Skyllas-Kazacos |
|
|
Electrodes
In electrochemistry, it is conventional to use metal or
carbon electrodes, connected by copper wire to an external
circuit, to carry current from one solution to the other.
Electricity can be delivered via the electrodes both to
the battery (to charge it) and from the battery (to discharge
it).
The team used graphite (a form of carbon) as the electrode
material in early trials, and then tried heat-pressing
carbon felt onto conducting plastic. Plastic electrodes
would be lighter, cheaper and easier to wash than graphite
electrodes.
They investigated commercially available conducting plastic,
which has carbon embedded in it, and found that its electrical
resistance was too high. They decided to make their own
conducting plastic. A student tried out varying formulations,
but had to overcome one serious problem: the high proportion
of carbon needed to make the plastic conduct electricity
also made it brittle.
This problem was solved by using graphite fibres rather
than powder. In laboratory trials, this resulted in a
plastic with good mechanical as well as electrical properties.
The team easily produced conducting plastic sheets in
the laboratory by compression moulding, but scale-up was
to prove difficult.
To produce the conducting plastic sheets in a factory,
the first step would be to blend graphite fibres with
plastic. Several manufacturers tried, but they found that
the fibres floated around and could not be fed into the
blender properly.
The next idea was to blend a batch of carbon and plastic
to make pellets, and then extrude the pellets, in a separate
process, to form a sheet. However, the company that specialised
in extrusion refused to accept the material as the carbon
fibre could erode its equipment.
So the team had to start from scratch. To produce a conducting
plastic without carbon fibres but with good mechanical
properties, Michael suggested trying a rubber additive.
A student with a background in plastics formulated a material
from a mixture of plastic, rubber and non-fibrous carbon
black.
However, they knew their new mix would have to be tested
extensively to find the best proportions and blending
time. Michael spent hours on the phone before he found
a company (Cabot in Melbourne) prepared to help. The company
did need to spend a lot of time on the project, even sending
the formulation to Europe for trials.
This was the worst stage of development for the team,
but they eventually patented a manufacturable material.
Getting the conducting plastic manufactured was a
great achievement.
Professor Maria Skyllas-Kazacos
Flow frames and end plates
Flow frames allow electrolyte to be distributed evenly
over the electrode surfaces. Each cell is made up of two
flow frames, one for each electrolyte. A battery, made
up of several cells, has two rigid end plates to hold
all the flow frames in place.
The team tested materials for the flow frames. At first,
they couldn't afford to make an injection mould, so they
machined each one. Rui Hong, a mechanical engineer and
long-term team member, did the engineering drawings for
the stack components. He used a CAD program and sent the
file to a numerically controlled machine (in the Mechanical
Engineering School at UNSW), which made the flow frames.
Irregularities in the frames led to leaks, so gaskets
were added. As the gaskets were attacked by the solution,
they had to be replaced regularly. Michael then sought
self-gasketing materials. He obtained some Santoprene
samples, but this material cannot be machined.
Thus problems led to solutions, but these led to new problems,
a common enough scenario in technical development, especially
on a tight budget.
Eventually, a grant was obtained to pay for the design
of an injection mould, but the funds allowed only one
shot at getting it right. Rui again did the engineering
drawings, and a company called Trade Tools made the mould.
Now the team could make multiple identical flow frames.
In scaling up from small to large battery stacks, the
continued use of the original solid metal end plates would
have made the battery too heavy. Finite element analysis
of the stresses showed that honeycomb aluminium would
be a suitable material. Michael contacted Formica Australia
and suggested it support the project; it did, fabricating
(and donating) end plates made from this strong but lightweight
material. |
|
|
| |
 |
Membrane.
Courtesy of Maria Skyllas-Kazacos |
|
|
Membranes
In the early experiments, a sheet of sintered glass (a
porous material, made by heating and compacting glass
powder, but not melting it) was placed between the solutions.
This was fine for proving the idea, but would not be suitable
for a commercial battery.
Miron purchased a membrane made by Asahi Glass Co, a subsidiary
of Mitsubishi, to replace the sintered glass. It cost
$1000 per square metre. He inserted the membranes in plastic
cells made in the University's workshop – and achieved
encouraging results.
Later, Michael negotiated with Dupont. The company donated
large quantities of Nafion, a high quality membrane. Another
multinational company, WR Grace, donated microporous separators.
The team tested the chemical and mechanical stability
of the membranes and measured the rates at which ions
diffused through them.
To make a cheaper and more stable membrane, Maria decided
to try filling the small holes in a porous plastic with
ion exchange resin. Starting with Daramic, made by WR
Grace and used in lead acid batteries, a student tried
cross-linking resin into the pores and across the surface,
then soaking the sheet in concentrated sulphuric acid.
This gave a composite membrane with 80% efficiency, compared
to Daramic's 40%.
The membrane developed by the team cost less than $50
per square metre, but they abandoned this work when the
Japanese licensees, Kashima-Kita Electric Power Corporation
and Sumitomo Electric Industries, developed cheap membranes
for use in the batteries. Development does not proceed
along well-defined pathways, and such dead ends and wasted
efforts are common.
Pumps and controls
Small, efficient pumps were available off the shelf, the
main selection criterion being that the parts in contact
with the solution be made of polyethylene or polypropylene.
Other materials would react with the acid and deteriorate
rapidly.
For the control system, Michael scrounged electronics
and begged suppliers to donate samples. Lecturer Dr Barry
Madden helped by designing some of the microprocessor
control equipment.
Battery chargers are very expensive. A large company quoted
to supply one, but could not guarantee that it would control
current. So the team employed an electrical engineer to
design and make a suitable charger, which was refined
over five years.
|
|
|
| |
 |
Testing.
Courtesy of UNSW. Photographer Steve Preece. |
 |
Testing in buggy.
Courtesy of UNSW. Photographer Steve Preece. |
 |
Battery in solar house.
Courtesy of Maria Skyllas-Kazacos |
|
|
Testing and demonstration
Continual testing is an essential part of development,
and often the test equipment has to be specially designed
for the project.
For instance, Rod McDermott adapted a boat speedometer
to measure flow rates, but the acid attacked its steel
shaft. Rod tried shrink-wrapping it in plastic, which
worked for a while. Then he tried using a polyethylene
ballpoint pen refill (with the ink removed!) to replace
the shaft; this also worked for a short time, but it eventually
leaked, and the strong oxidising conditions of the electrolyte
caused the device to fail.
All components were tested, as were single cells and batteries.
Stability was tested, as were the rates of charge and
discharge, the concentrations of various ions in solution,
the effectiveness of various additives, and battery efficiency.
The batteries were tested at different temperatures to
simulate the different conditions under which a commercial
battery might be used.
When one battery stack design was found to be less than
80% efficient, a clear perspex flow frame was made so
that the flow of electrolyte could be studied.
In a project aimed at optimising the reactive surface
area, a scanning electron microscope was used to examine
material samples that had been subjected to different
chemical and thermal treatments.
Batteries were tested over many months in a solar-powered
house in Thailand, a factory in Japan, and a golf buggy
in Sydney, as well as in the lab. These demonstration
projects helped prepare the battery for commercial release.
| | |
| |
 |
Michael Kazacos driving the buggy.
Courtesy of UNSW. Photographer Steve Preece. |
|
|
The
impacts
By 1997, the battery was ready for manufacture. The first
large-scale battery was installed by Sumitomo in Japan.
Mitsubishi and Sumitomo have installed several batteries
for load-levelling applications (storing energy when demand
is low and releasing it when demand is high, so that less
investment is needed in electrical generating plant).
A 2 megawatt battery (one able to deliver 2 million watts)
in a liquid crystal factory in Japan had a 'payback period'
of six months. There were more than ten power failures
during that period, which would have resulted in lost
production without the battery; the value of this production
was equal to the cost of the battery.
The aim of using vanadium batteries to store renewable
energy has also been satisfied. They have been used to
store energy generated by photovoltaic panels, and a battery
made by Sumitomo has stabilised the energy output of a
wind generator much better than any other battery.
There is much interest in using the battery in vehicles,
and Maria is championing this idea. She is working with
a UK-based company to develop new compact battery stacks
that can be installed in off-road electric vehicles for
trials in the UK and Europe. If these are successful,
further use in buses and cars can be expected.
The vanadium battery could have a huge impact on worldwide
transport and environment problems, particularly if solar
or wind energy is used for recharging.
| | |
| |
Links and references
UNSW battery info http://www.ceic.unsw.edu.au/centers/vrb
Life cycle http://www.te.hik.se/personal/tryca/battery/Rydh_LCA_V_PBA.pdf
Sumitomo http://www.sumitomoelectricusa.com/scripts/products/prp/redox.cfm
Overview http://www.geocities.com/CapitolHill/3589/VANADI2.HTM
Key
people
Professor Maria Skyllas-Kazacos – team leader
Michael Kazacos – laboratory manager
Rui Hong – researcher
Jobs
and skills required
Chemical engineer
Industrial chemist
Polymer scientist
Mechanical engineer
Electrical engineer
Discussion
questions
K-6
1. What is a battery and what does it do?
2. Name 10 things in your home or school which use a battery
for power and draw the different batteries they use. Discuss
the shapes and sizes of the batteries.
3. What is the largest and smallest battery you have seen?
4. What are some of the reasons for new batteries to be
developed?
7-10
1. What are the two reasons we need to store electricity?
2. What is the main problem with most rechargeable batteries?
3. What are the main types of batteries used in vehicles
today? What are their main disadvantages?
4. What are the future environmental implications of using
vanadium batteries in vehicles?
11-12
1. Explain the role that universities and post-graduate
students have in the innovation process.
2. What is meant by the term ‘scaling up’? What
are some of the difficulties with scaling up?
3. What does the term ‘R&D’ mean and what
does it include? Name one sector of the community which
is responsible for a great deal of Australian R&D.
4. Design an advertising poster for the vanadium battery
|
|
|
|
 |
|
|
|
