a comparison of new energy storage methods

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


• 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


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.


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/


• 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


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


• 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


• Improvements– Decreasing shunt

resistance– Decreasing

contamination of electrolytes

– With large systems – unwanted byproduct formation can harm the cell stack

Redox Flow Battery


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.


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?


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



• 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


• 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/


• 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/


• 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


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


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



• 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



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”.


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.


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


• 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


• 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/


• 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



• 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


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


• 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


• 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


• Improvements– Decreasing shunt

resistance– Decreasing

contamination of electrolytes

– With large systems – unwanted byproduct formation can harm the cell stack

Redox Flow Battery


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?


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.


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

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