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A Comparison of New Energy Storage Methods . Elliott Barr Dion Hubble Robert Piper (15 Minute Presentation) . Graphical Abstract. What type of power management system is appropriate for an grid-scale energy storage?. - PowerPoint PPT Presentation
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A Comparison of New Energy Storage Methods
Elliott BarrDion HubbleRobert Piper
(15 Minute Presentation)
Graphical Abstract
What type of power management system is appropriate for an grid-scale energy storage?
Figure adapted from: Electrical Energy Storage for the Grid: A Battery of Choices , Science 18 November 2011, Vol. 334 no. 6058 pp. 928-934
IntroductionUS power grids: lack of large-scale energy storage (~2.5%)
Waste of resources
Already being implemented in Japan, Europe
Why not here? Cost, safety concerns
New and improved technologies might address these concerns
Li-ion, Na/X, Redox-Flow, Supercapacitors, Thermal
Background figure adapted from: www.cntenergy.org Inset figure adapted from: en.wikipedia.org
Above: Power flow throughout the day, with and without the leveling
effect of energy storage
Background/motivation
• The power grid that is in place at the moment tends to fail, causing hundreds to thousands of people to be without electricity
• Electrical energy storage (EES) systems may be able to provide better reliability
• In the case of a power grid failure, EES systems store the energy needed ahead of time and can therefore minimize any down time
Power Grid Failure
http://covertress.blogspot.com/2012/03/vulnerability-of-us-power-grid-centers.html
Background/motivation
• The current power system in place relies heavily on fossil fuels (namely petroleum products)
• Our current system produces harmful gases to the environment
• EES systems can provide an alternative to fossil fuels that does not produce harmful gases
Fossil Fuels and Emissions
http://www.solarfeeds.com/is-the-u-s-ditching-clean-energy-for-fossil-fuels/
Basic PrincipalsBatteries
http://www.greenmanufacturer.net/article/tc/sage-supplier-lowering-costs-of-lithium-ion-batteries-for-ev-power-trains
Stores energy in electrode until external load is applied
Basic PrincipalsReduction-Oxidation Cells
http://www.pnl.gov/news/release.aspx?id=855
Stores energy in the electrolytes until an external load is applied
Vanadium Redox Flow Battery
Basic PrincipalsSuper Capacitors
Typical super capacitor with activated carbon
New design with carbon nanotubes
Remember: capacitance increases with plate area.Activated carbon simply increases surface area of the plates, allowing more charge to collect
http://www.engstuff.info/2010/11/ultra-capacitors-next-generation-charge.html
Work Performed (literally)• Lithium Ion• Sodium-Sulfur and
Sodium-Metal Halide Batteries
• Redox-Flow• Super capacitors/ Thermal
http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm
Lithium Ion Battery
• Battery consists of – Anode– Cathode – Electrolyte
• In Li-ion system materials are currently Lithium metal and a metal oxide for anode and cathode
http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm
Lithium Ion Battery
http://www.sciencemag.org/content/334/6058/928.abstract
• Li-ion batteries use chemical reactions to store electricity
• The transfer of Li+ ions from the anode to cathode allow for current to flow
• For ion transport an electrolyte is needed
Lithium Ion Battery
Practical Usage• Regarded as the battery
of choice for powering the next generation of hybrid electric vehicles (HEVs) as well as plug-in hybrids (PHEVs)
• Grid applications, considerable synergy should exist between the two areas
http://www.dashboardnews.com/2009/02/15/lithium-ion-car-batteries/
Lithium Ion Battery)Advantages• Wide variety of shapes
and sizes efficiently fitting the devices they power.
• Much lighter than other energy-equivalent secondary batteries
• Low self-discharge rate (~5-10% per month compared to over 30% per month in common Ni metal hydride batteries)
http://www.justlaptopbattery.com/about/
Lithium Ion BatteryDisadvantages• Cell Life
– Charging forms deposits inside the electrolyte that inhibit ion transport (dendrites)
– The increase in internal resistance reduces the cell's ability to deliver current
– Problem is more pronounced in high-current applications
• Internal Resistance– Internal resistance
increases with both cycling and age
– Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw
Deformation due to cycling
Chan, Candace. “High-performace litihium battery anodes using silicon nanowires”.
The Sodium-Based Battery
Figure adapted from: wastedenergy.net
• Technology has existed since the 1960s
• Originally developed by Ford for electric cars
• Battery of choice in Japan for load leveling/peak shaving.
• Based on β-alumina as a solid electrolyte
Sodium-Based Batteries (cont.)β-alumina
What is β-alumina?
NaAl11O17
Yellow: AluminumRed: OxygenBlue: Sodium
Isomorph of Aluminum Oxide:
Al2O3
Figure adapted from: www.ifm.liu.se
Sodium-Based BatteriesThe Na-S Cell
• Anode: molten Na
• Cathode: molten S
• Solid β-alumina electrode allows movement of Na+, just like the movement of Li+ in the Li-Ion battery.
• On discharge, forms sodium sulfides.
Figure adapted from: Electrical Energy Storage for the Grid: A Battery of Choices , Science 18 November 2011, Vol. 334 no. 6058 pp. 928-934
Sodium-Based BatteriesAdvantages
• High energy density• Small footprint (simple design)• Fairly high open-cell voltage (2.08
V for Na/S, 2.58 for Na/MeCl)• High charge/discharge efficiency
(nearly all e- flow is used for productive means)
• Low maintenance
Disadvantages• Thermal management• High cost of beta-alumina
fabrication• Ceramic fracture• High-temperature seals• Both sulfur and polysulfides are
corrosive
Figure adapted from: thefraserdomain.typepad.com
Redox Flow Batteries• Redox flow batteries are
comprised of two main parts: the cell stack and the electrolyte containers (tanks).
• These two parts are separate • Energy delivery depends on
number of cells stacked while power delivery depends on amount of electrolyte stored, hence this system can be optimized for energy delivery and/or power delivery.
http://www.sciencedaily.com/releases/2011/10/111014080045.htm
Redox Flow Batteries
• Flexible layout due to the separation of cell stacks and electrolyte containers
• Long life cycle due to the lack of solid-solid phase changes
• No harmful emissions to environment
• Low maintenance/risk for failure
• Tolerant to overcharge/overdischarge
Advantages
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Redox Flow Batteries
• Very complex compared to regular batteries
• Involves the design of tanks, pumps, sensors, controller units, and contamination reduction.
• The energy density is lower than that of typical batteries (Li-ion)
Disadvantages
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Super Capacitors • Improvement to regular
capacitors• Larger size vs capacitors• Multiple farads vs
micro/nano farads• Typical features:
– High power density (can release energy in seconds)
– Low energy density (cannot hold a lot of energy)
http://www.hwkitchen.com/products/super-capacitor-10f-2-5v/ http://www.ultracapacitors.org/index.php?option=com_content&Itemid=77&id=106&task=view
Super Capacitors
• Is used for small scale applications in electronics such as cell phones, wireless devices, mp3 players, and other similar devices
• A promising new area or development is laptop and cell phone charging (both wired and wireless)
• LED
Practical Usage
http://www.instructables.com/id/Supercapacitor-USB-Light/
Super Capacitors
• The voltage is set by the application (unless it is being used in parallel with a battery)
• Rechargeable and simple to do charge
• Very long cycle life compared to batteries
• Very fast charge and discharge rate
• High power rating
Advantages Disadvantages
http://www.supercapacitors.org/
• Power is only available for a short about of time
• Higher self-discharge rate than batteries (leakage current)
• Low energy capacity
Conclusions• The value of energy storage is
becoming increasingly evident
• The success of these applications of energy storage will depend on how well storage technologies can meet key expectations:
– Low initialized cost– High durability and reliability– Long life– High roundtrip efficiencies
http://www.wou.edu/las/physci/GS361/electricity%20generation/HistoricalPerspectives.htm
Assessment of Battery Choices
• Improvements– Increase thermal stability– Improve on the
deformation of substrate due to cycling
– Develop electrode materials on the basis of abundance and availability of the relative materials
Lithium ion Battery
http://thetechjournal.com/green-tech/researchers-found-new-power-source.xhtml
Assessment of Battery Choices
• Proven to be a viable solution, already in limited use
• Safety is an ongoing issue (most recently, caused a fire at a Japanese power plant)
• Operating temperature must be lowered to facilitate more widespread use
• A 30-year-old technology; needs to integrate new advances in materials fabrication, new chemistries
• Costs expected to decrease as use becomes more widespread
Figure adapted from: http://www.sae.org
Na-S Cell
Assessment of Battery Choices
• Improvements– Decreasing shunt
resistance– Decreasing
contamination of electrolytes
– With large systems – unwanted byproduct formation can harm the cell stack
Redox Flow Battery
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Further Suggested Research• Improvements in the
Li-ion manufacturing process: low temperature fabrication, organic electrodes (lower cost over lifecycle of battery, and lower carbon footprint for fabrication.
Figure adapted from: http://img.mit.edu
Further Suggested Research• New methods for
fabricating single crystals of β-alumina: fewer imperfections means higher Na+ conductivity
• Perhaps even new solid electrodes?
Figure adapted from: energyenvironment.pnnl.gov
Further Suggested Research• Redox-flow systems
at higher concentrations
• Typical concentration limit, ~8 M, limits energy storage potential
• Flowable inks being developed with concentrations in the 10 – 40 M range.
Figure adapted from: energyenvironment.pnnl.gov
References• Electrical Energy Storage for the Grid: A Battery of Choices
Science 18 November 2011Vol. 334 no. 6058 pp. 928-934
Questions
THANK YOU
A Comparison of New Energy Storage Methods
Elliott BarrDion HubbleRobert Piper
(50 Minute Presentation)
Graphical Abstract
What type of power management system is appropriate for an grid-scale energy storage?
Figure adapted from: Electrical Energy Storage for the Grid: A Battery of Choices , Science 18 November 2011, Vol. 334 no. 6058 pp. 928-934
IntroductionUS power grids: lack of large-scale energy storage (~2.5%)
Waste of resources
Already being implemented in Japan, Europe
Why not here? Cost, safety concerns
New and improved technologies might address these concerns
Li-ion, Na/X, Redox-Flow, Supercapacitors, Thermal
Background figure adapted from: www.cntenergy.org Inset figure adapted from: en.wikipedia.org
Above: Power flow throughout the day, with and without the leveling
effect of energy storage
Introduction
Figure adapted from: Electrical Energy Storage for the Grid: A Battery of Choices , Science 18 November 2011, Vol. 334 no. 6058 pp. 928-934
Background/motivation
• The power grid that is in place at the moment tends to fail, causing hundreds to thousands of people to be without electricity
• Electrical energy storage (EES) systems may be able to provide better reliability
• In the case of a power grid failure, EES systems store the energy needed ahead of time and can therefore minimize any down time
Power Grid Failure
http://covertress.blogspot.com/2012/03/vulnerability-of-us-power-grid-centers.html
Background/motivation
• The current power system in place relies heavily on fossil fuels (namely petroleum products)
• Our current system produces harmful gases to the environment
• EES systems can provide an alternative to fossil fuels that does not produce harmful gases
Fossil Fuels and Emissions
http://www.solarfeeds.com/is-the-u-s-ditching-clean-energy-for-fossil-fuels/
Background/motivation
• In the past, the cost of EES system technologies was higher than the cost of generating and transporting power to the US during peak hours
• With a decrease in the cost of these technologies, and an increase in the cost of fossil fuels, it makes sense to begin shifting our mainstream power generation system towards EES systems
Cost Considerations
http://webberenergyblog.wordpress.com/2012/03/25/how-to-make-alternative-energy-affordable/
Background/motivation
• Batteries– Stores energy in the electrode– Transfers energy via chemical rxn
(ion/electron transfer)– Only runs when it is needed
(connected to external voltage)– Types include: Li-based, Ni- based,
aqueous, and non-aqueous– Rechargeable (by reversing the
rxn)
• Reduction-Oxidation Cells– Stores energy in the redox species
within the cell
• Fuel Cells– Stores energy in the reactant
externally fed to the device (ie. Hydrogen in a Hydrogen fuel cell)
– Non-rechargeable
• Super Capacitors– Stores energy between two plates
containing an electrolyte– Charge stores on the electrode-
electrolyte interface.– Provide higher power and longer
life cycle than batteries
EES Systems
Basic PrincipalsBatteries
http://www.greenmanufacturer.net/article/tc/sage-supplier-lowering-costs-of-lithium-ion-batteries-for-ev-power-trains
Stores energy in electrode until external load is applied
Basic PrincipalsReduction-Oxidation Cells
http://www.pnl.gov/news/release.aspx?id=855
Stores energy in the electrolytes until an external load is applied
Vanadium Redox Flow Battery
Basic PrincipalsSuper Capacitors
Typical super capacitor with activated carbon
New design with carbon nanotubes
Remember: capacitance increases with plate area.Activated carbon simply increases surface area of the plates, allowing more charge to collect
http://www.engstuff.info/2010/11/ultra-capacitors-next-generation-charge.html
Work Performed (literally)• Lithium Ion• Sodium-Sulfur and
Sodium-Metal Halide Batteries
• Redox-Flow• Super capacitors/ Thermal
http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm
Lithium Ion Battery
• Battery consists of – Anode– Cathode – Electrolyte
• In Li-ion system materials are currently Lithium metal and a metal oxide for anode and cathode
http://electronics.howstuffworks.com/everyday-tech/lithium-ion-battery1.htm
Lithium Ion Battery (cont.)
• Commercially introduced by Sony in 90’s
• Outperform competing technologies (Ni-metal hydride, Ni-cadmium, and Pb-acid) by a factor of 2.5 in terms of delivered energy while performing high specific power.
http://commons.wikimedia.org/wiki/File:Sony_Li-ion_battery_LIP-4WM.jpg
Lithium Ion Battery (cont.)
http://www.sciencemag.org/content/334/6058/928.abstract
• Li-ion batteries use chemical reactions to store electricity
• The transfer of Li+ ions from the anode to cathode allow for current to flow
• For ion transport an electrolyte is needed
Lithium Ion Battery (cont.)Lithium-Air Cell • Lithium used as anode
• Porous conductive composite (carbon and a catalyst) used as cathode
• Cell is flooded with either aqueous or non-aqueous electrolytes
• Functionality – O2 from atmosphere dissolves in
electrolyte and is reduced– Upon discharge Li ions pass
through electrolyte and react with reduced O2
– Process is reversed on Charging
http://www.sciencemag.org/content/334/6058/928.abstract
Lithium Ion Battery (cont.)
Practical Usage• Regarded as the battery
of choice for powering the next generation of hybrid electric vehicles (HEVs) as well as plug-in hybrids (PHEVs)
• Grid applications, considerable synergy should exist between the two areas
http://www.dashboardnews.com/2009/02/15/lithium-ion-car-batteries/
Lithium Ion Battery (cont.)Advantages• Wide variety of shapes
and sizes efficiently fitting the devices they power.
• Much lighter than other energy-equivalent secondary batteries
• Low self-discharge rate (~5-10% per month compared to over 30% per month in common Ni metal hydride batteries)
http://www.justlaptopbattery.com/about/
Lithium Ion Battery (cont.)Disadvantages• Cell Life
– Charging forms deposits inside the electrolyte that inhibit ion transport (dendrites)
– The increase in internal resistance reduces the cell's ability to deliver current
– Problem is more pronounced in high-current applications
• Internal Resistance– Internal resistance
increases with both cycling and age
– Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw
Deformation due to cycling
Chan, Candace. “High-performace litihium battery anodes using silicon nanowires”.
Lithium Ion Battery (cont.)
Safety Considerations• Lithium-ion batteries can
easily rupture, ignite, or explode when exposed to high temperatures, or direct sunlight
• Short-circuiting a Li-ion battery can also cause it to ignite or explode
http://batteryuniversity.com/images/partone-5b-3.jpg
The Sodium-Based Battery
Figure adapted from: wastedenergy.net
• Technology has existed since the 1960s
• Originally developed by Ford for electric cars
• Battery of choice in Japan for load leveling/peak shaving.
• Based on β-alumina as a solid electrolyte
Sodium-Based Batteriesβ-alumina
What is β-alumina?
NaAl11O17
Yellow: AluminumRed: OxygenBlue: Sodium
Isomorph of Aluminum Oxide:
Al2O3
Figure adapted from: www.ifm.liu.se
Sodium-Based Batteriesβ-alumina
Properties of β-alumina
• High thermal and chemical stability• Low electronic conduction (it’s a ceramic!)• BUT high ionic conduction for Na+, which can jump from site to site – it’s
ability to conduct sodium rivals that of a electrolyte solution such as H2SO4
Figure adapted from: www.doitpoms.ac.uk
Sodium-Based BatteriesThe Na-S Cell
• Anode: molten Na
• Cathode: molten S
• Solid β-alumina electrode allows movement of Na+, just like the movement of Li+ in the Li-Ion battery.
• On discharge, forms sodium sulfides.
Figure adapted from: Electrical Energy Storage for the Grid: A Battery of Choices , Science 18 November 2011, Vol. 334 no. 6058 pp. 928-934
Sodium-Based BatteriesMetal-Chloride Variation
Figure adapted from: http://images.books24x7.com
Sodium-Based BatteriesWhy the need for a solid
electrode?
• High operating temperature (270-350 degrees C)
• Electrolyte solution not suitable: the electrodes are liquids, and above the boiling point of water.
• β-alumina, with high thermal stability but low σ, makes it possible.
Figure adapted from: theochem.unito.it
Sodium-Based BatteriesAdvantages
• High energy density• Small footprint (simple design)• Fairly high open-cell voltage (2.08
V for Na/S, 2.58 for Na/MeCl)• High charge/discharge efficiency
(nearly all e- flow is used for productive means)
• Low maintenance
Disadvantages• Thermal management• High cost of beta-alumina
fabrication• Ceramic fracture• High-temperature seals• Both sulfur and polysulfides are
corrosive
Figure adapted from: thefraserdomain.typepad.com
Redox Flow Batteries
• Research began in 70’s on Fe-Ti couple system using FeCl3 as oxidizing agent and TiCl2 as reduction agent.
• Ti changed to Cr in the 80’s because of improved performance developed by NASA
• Now – Fe-Cr system is expensive and requires high mantainance
• Leading redow flow technology: Vanadium redox flow battery (VRB)
• POS: VO2+ + 2H+ + e- VO2
+ + H2O• NEG: V2+ V3+ + e-
Redox Flow Batteries• Redox flow batteries are
comprised of two main parts: the cell stack and the electrolyte containers (tanks).
• These two parts are separate • Energy delivery depends on
number of cells stacked while power delivery depends on amount of electrolyte stored, hence this system can be optimized for energy delivery and/or power delivery.
http://www.sciencedaily.com/releases/2011/10/111014080045.htm
Redox Flow Batteries
• This technology was first developed to help the power grid through load leveling (as to not waste power)
• Now VRB technology is being used for power quality control, emergency/back-up power supply, and stabilization of renewable energy sources (such as solar or wind).
Practical Usage
http://lxinnovations.wordpress.com/
Redox Flow Batteries
• Flexible layout due to the separation of cell stacks and electrolyte containers
• Long life cycle due to the lack of solid-solid phase changes
• No harmful emissions to environment
• Low maintenance/risk for failure
• Tolerant to overcharge/overdischarge
Advantages
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Redox Flow Batteries
• Very complex compared to regular batteries
• Involves the design of tanks, pumps, sensors, controller units, and contamination reduction.
• The energy density is lower than that of typical batteries (Li-ion)
Disadvantages
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Super Capacitors • Improvement to regular
capacitors• Larger size vs capacitors• Multiple farads vs
micro/nano farads• Typical features:
– High power density (can release energy in seconds)
– Low energy density (cannot hold a lot of energy)
http://www.hwkitchen.com/products/super-capacitor-10f-2-5v/ http://www.ultracapacitors.org/index.php?option=com_content&Itemid=77&id=106&task=view
Super Capacitors
• First used in military applications for starting tank or submarine engines
• Can be used in combination with batteries for many applications
• Remote sensors– Other applications with a
high pulse current
Practical Usage
http://www.powersystemsdesign.com/autobatteryassist1?a=1&c=1153
Super Capacitors
• Is used for small scale applications in electronics such as cell phones, wireless devices, mp3 players, and other similar devices
• A promising new area or development is laptop and cell phone charging (both wired and wireless)
• LED
Practical Usage
http://www.instructables.com/id/Supercapacitor-USB-Light/
Super Capacitors
• The voltage is set by the application (unless it is being used in parallel with a battery)
• Rechargeable and simple to do charge
• Very long cycle life compared to batteries
• Very fast charge and discharge rate
• High power rating
Advantages Disadvantages
http://www.supercapacitors.org/
• Power is only available for a short about of time
• Higher self-discharge rate than batteries (leakage current)
• Low energy capacity
Conclusions• The value of energy storage is
becoming increasingly evident
• The success of these applications of energy storage will depend on how well storage technologies can meet key expectations:
– Low initialized cost– High durability and reliability– Long life– High roundtrip efficiencies
http://www.wou.edu/las/physci/GS361/electricity%20generation/HistoricalPerspectives.htm
Assessment of Battery Choices
• Improvements– Increase thermal stability– Improve on the
deformation of substrate due to cycling
– Develop electrode materials on the basis of abundance and availability of the relative materials
Lithium ion Battery
http://thetechjournal.com/green-tech/researchers-found-new-power-source.xhtml
Assessment of Battery Choices
• Proven to be a viable solution, already in limited use
• Safety is an ongoing issue (most recently, caused a fire at a Japanese power plant)
• Operating temperature must be lowered to facilitate more widespread use
• A 30-year-old technology; needs to integrate new advances in materials fabrication, new chemistries
• Costs expected to decrease as use becomes more widespread
Figure adapted from: http://www.sae.org
Na-S Cell
Assessment of Battery Choices
• Improvements– Decreasing shunt
resistance– Decreasing
contamination of electrolytes
– With large systems – unwanted byproduct formation can harm the cell stack
Redox Flow Battery
http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/
Further Suggested Research• Improvements in the
Li-ion manufacturing process: low temperature fabrication, organic electrodes (lower cost over lifecycle of battery, and lower carbon footprint for fabrication.
Figure adapted from: http://img.mit.edu
Further Suggested Research• New methods for
fabricating single crystals of β-alumina: fewer imperfections means higher Na+ conductivity
• Perhaps even new solid electrodes?
Figure adapted from: energyenvironment.pnnl.gov
Further Suggested Research• Redox-flow systems
at higher concentrations
• Typical concentration limit, ~8 M, limits energy storage potential
• Flowable inks being developed with concentrations in the 10 – 40 M range.
Figure adapted from: energyenvironment.pnnl.gov
References• Electrical Energy Storage for the Grid: A Battery of Choices
Science 18 November 2011Vol. 334 no. 6058 pp. 928-934
Questions
THANK YOU