You need balls of steel, deep pockets, a crystal ball and a touch of good fortune to bring a new battery develpoment to market. Barrie Lawson explains why.
Breathroughs in battery technology stories are as common now as ‘magic bullets’ for cancer cure stories were in the mainstream media a decade ago. It doesn’t happen like that in Medicine and it certainly doesn’t happen in the battery world. Applications engineers in electronics still wonder why. If that’s your role in business, this article is for you.
The recent reversals in fortune of US lithium-ion cell maker A123 show that the best laid plans of mice and battery makers often go awry.
Over two billion batteries, worth over US$30 billion, are produced every year (2012) for use in laptop computers, mobile phones, cameras, consumer electronics products and all the huge rewards await those who can deliver better batteries for these products and everything else you can imagine.
In response, the challenge has been taken up by academic and industrial research institutions all over the world and there is a regular flow of announcements about minor improvements in battery technology accompanied from time to time by claims of more significant breakthroughs. Newspapers and even BEST magazine publicise this news leading to great expectations, from potential battery users and specifiers, of the imminent availability of improved products. Sadly, these expectations are often over optimistic, premature and doomed to disappointment.
It’s an unfortunate fact that what’s demonstrated in the laboratory can not necessarily be converted into a commercial product. If the technology is indeed viable it can take many years of development to bring it to the market. A ten year gestation period for new cell chemistries is typical in the industry. And because a lot can happen in ten years—economic cycles, political upheavals not mention other disruptive technologies it’s quite a miracle for anything new and high risk to flourish at at all.
Tasks and Considerations
The following table lists the main tasks involved in developing new battery chemistries and indicates the key performance parameters to be considered and how they may affect each other.
Finding the optimum cell chemistry which simultaneously satisfies all the cell performance requirements is fiendishly difficult because performance parameters are all inter-related. Improving just one of these parameters can adversely affect the performance of one or more of the others. Only repetitive testing and particularly lifetime testing can verify the performance each time a change is made, so inevitably the process can take many years.
Even if you’re an engineer with no basic high school chemistry, the basic principles are not hard to grasp. Of the 118 elements in the periodic table only 79 are stable and possible candidates for use in electrochemical cells. The remaining 39 are radioactive and of these, 4 are still un-named and 1 is predicted but not yet confirmed.
Of the 79 possible candidates for energy cell electrodes, for various reasons not all of them are suitable. The following are some of the factors influencing the choice.
The periodic table gives an indication of the “potential”, in both senses of the word, of elements to be used in battery electrode pairs. The elements on the left side of the table have a surplus of electrons and are known as reducing elements. By contrast the elements on the right side of the table are oxidising elements which have a deficit of electrons. The magnitude of the electron surplus or deficit is known as the standard electrode potential of the element. Similarly, compounds containing the elements tend to have characteristic electrode potentials indicating their reduction or oxidation capacity.
Elements or compounds with the greatest possible negative electrode potential are chosen for cathodes and elements or compounds with the highest possible positive potential are chosen for the anodes. The terminal voltage of the cell is determined by the difference in the electrode voltages of the elements or compounds forming the cathode and anode and the maximum possible cell terminal voltage is achieved by maximising this difference.
Maximising the cell voltage may also allow higher cell energy density but there are other factors involved, such as the crystal structure of the elements and whether or not they are gaseous at ambient temperature.
Reversibility of the Chemical Reaction
Not all potential electrode pairs are able to produce a reversible reaction. This rules out many potential combinations of elements.
For a rechargeable battery, the chemical reactions between the elements involved must obviously be reversible. This further limits the pool of electrode pairs which can be used. But, to complicate matters, there may be many possible chemical reactions between compounds of the electron pair. These side reactions will progressively consume the active chemicals and so must be suppressed.
Once a suitable reversible chemical reaction has been discovered, it is not unusual for this desirable reaction to fade away after only a few cycles. A major task in developing practical commercial products is to improve and extend this cyclability. Cycle testing can take anything from a few days to several months depending on how good the cells are and the C-rate specified.
The ability of electrode materials to absorb and give up again the ions from the electrolyte is known as their reversible capacity and is measured in milliAmperes per gram (mAh/g). To maximise a cell’s storage capacity, the electrode materials should be chosen from elements or compounds with high reversible capacity. To optimise the use of the volume available within the cell case, the anode and cathode should have the same reversible capacity, but because of the difference in the materials used in the two electrodes it may not be possible to balance the capacity with equal sized electrodes. In this case the volume of the material with the lowest reversible capacity must be increased to compensate. This is achieved by controlling the thickness of the electrode coating on the current collector foil.
Optimum Reaction Temperature
Most batteries are designed to work at their best between 10°C and 35°C, just as we are ourselves. Beyond these limits, life tends to become more difficult. The performance of most batteries suffers at very low temperatures, there is the possibility of freezing the electrolyte and chemical reactions are slower. Aarhenius showed that for every increase of 10° C in temperature, the chemical reaction rate doubles. While this enables the battery to deliver more power, it also moves it closer to the temperature at which some of the chemical constituents can break down, destroying the battery. The active chemicals are therefore usually chosen to allow maximum operating temperature range.
Some batteries, however, depend for their operation on molten salts and this liquid state may only occur at very high temperatures. An example is the sodium nickel chloride (NaNiCl) or Zebra battery which operates at over 270°C and the sodium sulphur (NaS) battery which works between 320°C and 340°C.
Electrode Particle Properties
Control of the size and shape of the particles forming the electrodes is probably the most important factor influencing cell performance.
• Crystal Morphology
The power handling capacity of the cells depends on the surface area of the electrodes and this is maximised by making the particle size as small as possible.
The impedance of the cells depends on maximising the contact between the particles so that small regular shapes are required.
Conductivity across the electrode is also improved by coating the particles with a very thin conductive layer a few nanometres thick with a material such as carbon.
• Mechanical Stress
Intercalation of the Lithium ions into the crystal structure of the individual particles making up the electrode can cause the volume of the particles to increase causing structural changes and stresses in the crystal structure. When the direction of the current through the cell reverses, the particle will contract back to its original size. Cycling the cell by charging and discharging, creates repetitive stresses which can eventually lead to cracking of the particles and this in turn reduces the contact between particles increasing the electrical resistance across the electrode.
Passivation is a double edged sword. It forms what is called the Solid Electrolyte Interphase (SEI Layer) on the surface of the electrode. In most cells this is unwanted since it inhibits the chemical reaction between the ions in the electrolyte and the electrode material thus increasing the internal impedance of the cell. But in some cell chemistries (some flavours of lithium, but not all) the SEI layer is needed to provide essential control or moderation of the chemical transformation in the cell by preventing over-reaction between the electrodes and the electrolyte.
• Nano Materials
The necessary small particle sizes of the electrode materials are normally produced by ball milling of the electrode powder down to particle sizes of 100 nanometres or less. For ultimate performance, recent research has indicated that further improvements may be possible by using nano structured materials with precisely controlled crystal structures.
Carbon nanotubes have very high reversible capacity and their linear structure makes their surface more accessible to the electrolyte.
Silicon has excellent reversible capacity when used as an anode but it suffers from the problem of the large change in volume of the Silicon crystals during intercalation which causes the crystals to crack when the cells are repetitively cycled. This problem can be alleviated by using silicon nanowires which have excellent tensile strength and so are less affected by the problem of volume change.
The use of nano structured materials holds out great promise for batteries with higher energy density and longer life but these materials require more sophisticated, and expensive, production processes such as chemical vapour deposition (CVD) and so far these materials have not yet been available in the quantities needed for high volume cell production.
• Toxicity (Electrodes)
The use of some metals such as cobalt as well as cadmium and even Lead which have all been used for many years in batteries has been deprecated because their uncontrolled disposal is deemed to damage the environment.
This is always an issue. It rules out the use of some exotic materials in battery manufacture.
Electrolytes must have high ionic conductivity, particularly for high power applications. They should also have good wetting characteristics. Wetting is the ability to improve the contact between the electrode and the electrolyte at the surface of the electrode and also to aid the transit of the ions through the separator.
Most batteries currently available operate below 4 Volts. While it would be possible to choose electrode pairs capable of providing a terminal voltage of 6 Volts or more, this potential is limited because most electrolytes breakdown with electrode potential differences of about 4.5 Volts. This puts another limitation on which combinations of elements can be used in the cell.
Similarly electrolytes can not tolerate very high temperatures. The most commonly used electrolyte salt used in lithium batteries, lithium hexafluorophosphate (LiPF6), decomposes to form hazardous highly reactive hydrofluoric acid (HF) if mixed with water or exposed to moisture. Apart from being highly toxic to humans, the presence of HF in cells will also cause degradation of other chemicals in the cells. Cell production and assembly must therefore be carried out in ”dry rooms” to prevent HF formation.
At very low temperatures some aqueous electrodes will freeze. The freezing temperature of the sulphuric acid electrolyte in a fully charged lead‑acid battery, for example, is around -70°C. As the state of charge decreases however the specific gravity of the electrolyte decreases as the percentage of water in the electrolyte increases so that at 40% state of charge, the electrolyte will freeze at around -9°C.
One more problem with electrolytes is that some of the metals used in energy cells may dissolve in some electrolytes. For example, in lithium-ion cells, at low state of charge, when the cell voltage has dropped to below about 2.5 Volts, the copper anode current collector dissolves in the electrolyte. When the voltage rises again the copper ions come out of solution leaving metallic copper particles spread around the electrolyte, possibly causing short circuits.
Materials Requirements – Non-Active Components
Electrode materials are normally supplied in powder form but for use in the cell they must be coated on to the electrode current collector foils, usually aluminium and/or copper, in a homogeneous layer to form a conductive mass with a precisely controlled thickness. This is the job of the binder materials. They are conductive materials dissolved in a temporary solvent to form a carrier in which the electrode powder is mixed to form a slurry which is spread over the foil current collectors enabling the electrode powder to adhere to the foil. The viscosity of the slurry must be tightly controlled to ensure consistent and even coating of the electrode layer. Subsequent passage of the coated foils through heating ovens, drives off the solvents leaving a solid coating of electrode material on the foils with the binder providing a conductive path between the electrode particles.
Changing the composition of the binders can affect the viscosity of the slurry, the adhesion of the electrode to the foil, the conductivity of the cells as well as the self discharge.
Besides the solvents used in the binders, non-active solvents may also be necessary to carry the electrolyte. In order to get the optimum performance from these solvents it may be necessary to resort to the use of toxic materials. N-methyl pyrrolidone (NMP), which has been shown to cause birth defects when pregnant women have been exposed to it, is one such solvent used by the majority of Lithium battery manufacturers in applying a coating on the electrodes of lithium batteries.
• Chemical Additives (Doping)
Various additives may be incorporated into the chemical mix to optimise performance with the following aims:
o Promotion of SEI Layer
o Catalysts to promote the chemical reactions
o Improvement in conductivity or internal impedance
o Improvement in wetting
o Reduction in self discharge
o Overcharge protection
o Dendrite suppression
o Prevention of cracking of the electrode particles
o Improvement of temperature range
o Fine ceramic coating of the separator to prevent short circuits
o Flame retardation
It should be noted that the introduction of any additive into the cell will reduce the space available for the active chemicals and could therefore reduce the cell capacity.
The separator is a non-conductive porous barrier between the anode and the cathode. In cells which operate at around room temperature, or slightly above, the separator is usually a porous membrane in the form of a polypropylene (PP) or polyethylene (PE) plastic film with very small micro-pores. It must be very thin while mechanically stable at elevated temperatures of 120 °C or more and subject to high pressures. It is technically difficult to produce and is therefore one of the high cost items in the battery.
High temperature, molten salts batteries use ceramic separators.
• Mechanical parts
Mechanical parts include the electrode current collector foils, tabs to take off the current, external terminals, the case, seals, insulation and pressure vents. These must all be custom designed for a new cell and optimised where appropriate for electrical and thermal conductivity, corrosion resistance, weight and cost. Any essential safety devices such as pressure vents and circuit interrupt devices (CIDs) which may have to be incorporated into the cells to meet safety targets will displace the active chemicals thus reducing the potential capacity of the cell.
Testing during the design phase involves a very wide range of in depth tests to analyse both the chemical and physical properties of the materials used and to evaluate their electrical, mechanical, thermal and life time performance in completed cells under different environmental and abuse conditions.
Carrying out these tests needs a well equipped test facility, with environmental chambers and the ability to cycle cells through repetitive charge discharge cycles and to perform chemical analysis, calorimetry, electrical measurements, mechanical stress testing, optical and electron microscopy, mass spectrometry, X-ray inspection and failure analysis.
Once the cell chemistry has been agreed, work can commence on the cell design.
Key design parameters are:
• Mechanical strength and abuse tolerance including rigidity, immunity to vibration, crushing and penetration
• Heat removal
• Corrosion resistance
• Pressure Release
Test programmes must be developed to validate the design.
Scalability of Materials Supply
The scalability of manufacturing the active chemicals should not be underestimated. It may be easy to produce a few hundred grams of electrode powders in the laboratory using the wide range of equipment at their disposal, but producing tens of tons of the materials with the desired characteristics using relatively simple processes is a major engineering task. It also depends on the availability of suitable precursor materials.
Processes must be put into place to ensure the high purity and consistency of the electrode powders in very high volumes but the biggest challenge is to obtain the necessary precise control of the particle size and shape and to apply any surface coatings which may be required. This may need the development and installation of dedicated production facilities costing tens of millions of dollars to guarantee the purity and the particle morphology and to prevent cross contamination with other products.
The spider diagram below is a management tool used during development to represent the status of the cell performance and the design trade-offs. In this hypothetical example, the blue line represents the desired cell performance and the red line represents the actual measured performance achieved.
The following are some further performance parameters and dependencies together with more general requirements and trade-offs which must be considered in optimising the performance of the complete battery.
Storage capacity (energy density), cycle life, rate capability and self discharge are the battery’s key performance indicators and each time materials or design changes are made it is necessary to confirm that these parameters are not adversely affected. Monitoring the cycle life after each change is particularly time consuming.
• Storage Capacity
This depends on the reversible capacity of the materials used for the electrolytes and the volume of active chemicals used in the cell.
• Cycle Life
The cycle life depends on many factors including the following:
o Stability of the active materials
o Suppression of side reactions
o Suppression of dendrite formation
o Prevention of leaks
o Operating temperature range
o Build up of the SEI layer (In most lithium chemistry variants)
o Intensity of use
• Rate Capability
High rate performance is a prerequisite for both high power delivery and fast charging. This is particularly important for high capacity batteries, such as those used in electric vehicle traction batteries, which must use very high charge rates in order to achieve reasonable charging times and also to capture the high current pulses of regenerative braking energy.
The ability of the battery to accept very high currents is determined by the following factors:
o High surface area electrodes
o Small particle sizes
o Low intercalation volume change to avoid mechanical stress on the particle crystal structures to avoid cracking of the particles
o Low internal impedance to minimise the energy loss and heat generation in the cell.
o Good internal thermal conduction of the materials within the cell to conduct heat away from the cell core to the surface of the cell
• Self Discharge
This is the unwanted chemical reaction in the battery which reduces its stored charge when it in its quiescent or idle state due to current leakage through the electrolyte. This leakage can be minimised by reducing the size of the micro-pores in the separator, but this could possibly increase the cell’s internal impedance. It could also have a cost impact since the separator is one of the high cost components in the battery.
Like many battery parameters self discharge is temperature dependent.
• Energy Density
Key to achieving smaller and lighter batteries is increasing the energy density of the cells. Choosing lighter elements or compounds for the electrodes is the first obvious step and using materials with the greatest reversible capacity is the second.
A special category covers metal-air batteries of which lithium-air is an example. It actually uses oxygen rather than air as the active chemical in a porous carbon cathode structure. The main benefit of this technology is that the cathode material, the oxygen, is not carried around in the battery but is taken from the air as required resulting in a major weight saving.
There are still many problems to solve before this technology is ready for commercialisation. The current carrying capacity is very low, it has poor cyclability and low coulombic efficiency.
Another major challenge involves developing a method of separating oxygen from the air, since moisture and CO2 can poison the lithium electrode.
The energy density of the complete cell must of course take into account of the weight of all the non-active components of the cell including the case and the terminals.
• Internal Impedance
The internal impedance is not only due to the resistivity of the active materials in the cell, it also depends on the quality of the contacts between the individual electrode particles. For this reason particles should be small with a regular shape. Conductivity as noted above is increased by coating the cells with a very thin layer of conducting compound and by using conductive binders. As also noted above, introducing additives can reduce the cell capacity.
• Operating Temperature Range
Practical batteries require the operating temperature range to be as wide as possible but this is limited by the battery chemistry and the breakdown temperature of some of the components. In extreme environments heating and cooling may be required to keep the cells within their operating temperature range.
See also Optimum Reaction Temperature above.
• Heat Generation
Another consideration in cell design is the amount of heat generated in the cell. Exothermic reactions between the chemicals used in the cell and Joule heating due to I2R heating of the cell components due to the passage of the electric current both contribute to the temperature increase in the cell during operation.
• Heat Removal
To keep cells within their operating temperature range, the heat generated by the chemical reaction as well as the Joule heating must be removed from the cells. The materials used in the cells should therefore have the maximum thermal conductivity to conduct the heat away from the core of the cell to the surface. The cell casing should be a good conductor and should have the maximum surface area to maximise the heat transfer. Cylindrical cells have a relatively small surface area so to get the heat out of the cells some designs use a metal pin through the jelly roll down the centre of the cylinder to provide an additional heat conduction path to the base of the cell.
• Coulombic Efficiency
The coulombic, or round trip, efficiency losses of the cells during a complete charge – discharge cycle are due to two causes, the hysteresis losses during the cycle and the I2R, joule heating losses due to the current flow through the resistive components of the cells. The first is fixed and is inherent in the cell chemistry, but some limited control over the cell impedance is possible as noted in the previous paragraph. Hysteresis losses are particularly high in the proposed Lithium-air batteries.
The coulombic efficiency losses of the cell may be very small but when the cell is used in a battery the overall coulombic efficiency losses of the battery could be considerably higher if the battery needs a Battery Management System (BMS) for its protection and safety. The energy consumed by the essential battery BMS should be considered as an energy loss associated with the cells and this could substantially reduce the overall coulombic efficiency. This could be reduced even further if the battery needs cooling or heating for its safe operation. The energy lost in the necessary thermal management system should also be taken into account when calculating the Coulombic efficiency.
• Suppression of Side Reactions
Side reactions are unwanted chemical reactions or physical changes which can take place between any of the materials within the cell. They cause loss of the active chemicals which may form other compounds thus reducing the cell capacity and cycle life. Many are almost imperceptible and lead to gradual battery ageing. The first line of defence is to choose cell materials which do not tend to have so many possible chemical combinations. Metals with multiple possible oxidation states are prone to these problems. In general, side reactions are controlled by keeping the conditions inside the cell within tight operating conditions of temperature, pressure and electric field or by adding chemical within the cell which tend to inhibit these reactions.
The following are some examples of more obvious problems:
o Dissolution of the electrodes
Lithium-sulphur cells offer very high theoretical energy storage capacity but they suffer from side reactions with the electrolytes. While both sulphur and lithium disulphide are relatively insoluble in most electrolytes, many of the intermediary polysulfides are not. The dissolving of the polysulphides into the electrolytes causes irreversible loss of the active sulphur material reducing the cycle life of the cell. The search for suitable alternative electrolytes or a method of immobilising the polysulphides continues until acceptable cell performance can be guaranteed.
The evolution of gas from chemical reactions within a cell may occur in cells such as nickel-cadmium and lead-acid which have aqueous electrolytes if the cell is operated outside of its normal tolerance limits. Once charging is complete, continuing to pump energy into the cell can cause electrolysis of the electrolyte giving rise to the release of oxygen and hydrogen. For this reason all nickel-cadmium and many lead-acid cells are sealed to keep the evolved gases within the cell case and encourage recombination.
A more serious form of gassing occurs when cells are subject to over-heating. In lithium cells for instance, an early step towards thermal runaway is the breakdown of the organic electrolyte resulting in the emission of flammable gases. This breakdown is not reversible. The cell cases are sealed to keep these gases from escaping, but the pressure in the cell also rises due to the release of the gases and could ultimately lead to the explosion of the cell. For this reason the cells contain pressure vents or other forms of pressure release to allow the gases to escape in a controlled manner before the pressure becomes critical.
o Metal deposition
Metal deposition is another form of unwanted chemical reaction. In lithium batteries two forms of metal deposition may occur, lithium plating and also dissolution of the electrodes.
There is a limit to the rate at which intercalation can occur in the carbon cathode during charging. Trying to force too much charging current through the cell can exceed this limit and the lithium ions with nowhere to go are deposited on the surface of the cathode in the form of metallic particles. This results in an irreversible capacity reduction in the cell and possible short circuits. The potential rate of intercalation decreases with temperature so that this problem gets much worse at low temperatures.
o Dendrite growth
This is the crystalline growth of the electrode material and is not a chemical change, but a physical change which occurs as the cell ages. As the crystals grow the larger structure reduces the conductivity of the electrode and also the cell capacity. Eventually the crystals may penetrate the separator possibly causing short circuits and destroying the cell.
This used to be a serious problem with many cells but this problem has now been solved by a variety of methods such as adding chemical additives to the electrolyte or the electrodes and by employing more rigid separators.
The presence of certain impurities in the chemicals used in the cell can poison the electrodes. As noted above this is a problem with Oxygen or air based electrodes such as Lithium air cells (as well as Fuel Cells) but it can apply to any chemical mix.
Toxicity does not just involve the electrode materials and the disposal of used batteries. More serious problems arise from the exposure to hazardous raw materials such as solvents and reactive chemicals used in manufacturing.
Account must also be taken of exposure to the emission of hazardous products from the accidental breakdown of the chemicals employed in the cells. Electrolytes in particular can be quite dangerous.
In certain lithium cells they produce highly reactive hydrofluoric acid on contact with water, but in the uncontrolled breakdown of the cells due to abuse or accident, a variety of toxic and flammable compounds are emitted. It should be a design goal to minimise these potential dangers which may occur long after the cell has left the factory.
Apart from toxicity, the possibilities of fire or explosion must also be investigated and minimised. A series of abuse tests must be carried out on the complete cells to ensure that the cells meet minimum safety standards.
As part of the product design and qualification process it is prudent and in some industries, such as the automotive and aerospace industries, mandatory to carry out a Failure Modes and Effects Analysis (FMEA) during the development process. This is a formalised design review process involving multi-disciplined teams to identify possible failures in the product, and to classify the probability of the occurrence of the failure and the severity of its consequences followed by an action plan to design out potential failure modes.
An obvious requirement is that the active chemicals should be made up from low cost, commonly available materials.
External Support and Control
Conventional cells such as lead-acid, nickel-cadmium and nickel-metal hydride operate in stand alone mode without the requirement of support from any external systems. More recent cell designs however introduced over the last few years use more reactive chemistries which require dedicated monitoring and control systems.
• Battery Management System (BMS)
The BMS provides the necessary operating support to ensure safe and long life operation. The systems are tailored to specific battery types and applications. They may have any or all of the following functions:
o Battery Monitoring – To monitor the current condition of the battery, voltages, temperatures and currents
o Cell Protection – To prevent abuse of the battery
o User Protection – To protect the user from battery malfunctions
o Cell Isolation – In case of a malfunction
o Cell Balancing – To prevent interactions between the cells from causing cell failures
o Charger Control – To communicate with the charger, to control the charging profile and to set the charging cut-off condition
o State of Charge (SOC) – Calculating the amount of energy left in the battery
o Thermal Management – Providing the required control signals to switch on heating or cooling as necessary
This all adds to the cost of the battery applications but not to the cells themselves. Nevertheless this cost and complexity of an associated BMS could impede the introduction of a new cell technology if the BMS is necessary to make it work and to keep it safe.
Energy cells are sold in huge quantities. It is a competitive market and automated production in clean room conditions is essential if cost and safety targets are to be met. Furthermore it is very difficult, if not impossible, to achieve the very high precision and quality standards by using manual production methods.
Cell components must therefore be designed with automation in mind, preferably to use existing or industry standard automation equipment. Otherwise new automated manufacturing, assembly and test equipment must be designed for the product.
Development Time Scale
There are five major contributors to the time necessary to design and develop a new battery product to the point where it is ready for market launch as noted below:
• Chemistry optimisation
• Repetitive testing and performance verification
• Cell design
• Manufacturing equipment design and installation
• Development of bulk materials production equipment
The search for the optimum chemistry which simultaneously satisfies all the performance requirements and the repetitive testing required to verify performance each time a change is made are extremely time consuming. Life cycle testing also results in the destruction of thousands of cells before the design is fully approved.
Furthermore it is not possible to carry out all of these tasks in parallel. Production facilities can not be designed or commissioned before the feasibility of the cell chemistry has been confirmed.
A development period of ten years to complete all of these tasks is typical in the industry.
Apart from the costs of a ten year research and development programme, there are huge investment costs involved in setting up a new manufacturing facility. The cost of setting up a new cell manufacturing facility is typically between US$200 million and US$500 million with possibly another US$50 million or more for an electrode powder manufacturing facility. Because it is very difficult to see ten years into the future with any certainty, there will be several “go – no go” decision points during the development period as the feasibility is confirmed and the risk becomes progressively lower.
Finding someone with deep pockets to take on this massive investment which has a payback period extending way beyond 10 years is another challenge.
Major cost savings can be made if it is possible to design the product to use standard cell sizes and configurations and to be able to be manufactured using industry standard production processes, but it will not knock much time off the overall development period.
The next time a laboratory announces a breakthrough in battery technology, bear the above issues in mind and check the status before you decide to incorporate it into your applications.
Barrie Lawson is a consultant and edits the Electropaedia web site www.mpoweruk.com