A Comparison of New Energy Storage Methods

1. A Comparison of New Energy Storage Methods Elliott Barr Dion Hubble Robert Piper (15 Minute Presentation)

2. 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

3. Introduction Above: Power flow throughout the day, with and without the leveling effect of energy storage Background figure adapted from: www.cntenergy.org Inset figure adapted from: en.wikipedia.org

4. Background/motivation Power Grid Failure • 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 http://covertress.blogspot.com/2012/03/vulnerability-of-us-power-grid-centers.html

5. Background/motivation Fossil Fuels and Emissions • 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 http://www.solarfeeds.com/is-the-u-s-ditching-clean-energy-for-fossil-fuels/

6. Basic Principals Batteries Stores energy in electrode until external load is applied http://www.greenmanufacturer.net/article/tc/sage-supplier-lowering-costs-of-lithium-ion-batteries-for-ev-power-trains

7. Basic Principals Reduction-Oxidation Cells Stores energy in the electrolytes until an external load is applied Vanadium Redox Flow Battery http://www.pnl.gov/news/release.aspx?id=855

8. Basic Principals Super Capacitors Remember: capacitance increases with plate area. Activated carbon simply increases surface area of the plates, allowing more charge to collect Typical super capacitor with activated carbon New design with carbon nanotubes http://www.engstuff.info/2010/11/ultra-capacitors-next-generation-charge.html

9. 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

10. 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

11. Lithium Ion Battery • 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 http://www.sciencemag.org/content/334/6058/928.abstract

12. 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/

13. 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/

14. Lithium Ion Battery Disadvantages 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 • 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 Deformation due to cycling Chan, Candace. “High-performacelitihium battery anodes using silicon nanowires”.

15. The Sodium-Based Battery • 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 Figure adapted from: wastedenergy.net

16. Sodium-Based Batteries (cont.) β-alumina What is β-alumina? Yellow: Aluminum Red: Oxygen Blue: Sodium Isomorph of Aluminum Oxide: Al2O3 NaAl11O17 Figure adapted from: www.ifm.liu.se

17. Sodium-Based Batteries The 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

18. Sodium-Based Batteries Advantages Disadvantages Thermal management High cost of beta-alumina fabrication Ceramic fracture High-temperature seals Both sulfur and polysulfides are corrosive • 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 Figure adapted from: thefraserdomain.typepad.com

19. 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

20. Redox Flow Batteries Advantages • 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 http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/

21. Redox Flow Batteries Disadvantages • 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) http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/

22. 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

23. Super Capacitors Practical Usage • 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 http://www.instructables.com/id/Supercapacitor-USB-Light/

24. Super Capacitors AdvantagesDisadvantages • 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 • Power is only available for a short about of time • Higher self-discharge rate than batteries (leakage current) • Low energy capacity http://www.supercapacitors.org/

25. 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

26. Assessment of Battery Choices Lithium ion Battery • 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 http://thetechjournal.com/green-tech/researchers-found-new-power-source.xhtml

27. Assessment of Battery Choices Na-S Cell • 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

28. Assessment of Battery Choices Redox Flow Battery • Improvements • Decreasing shunt resistance • Decreasing contamination of electrolytes • With large systems – unwanted byproduct formation can harm the cell stack http://en.kisti.re.kr/blog/post/5kw-class-redox-flow-battery-developed/

29. 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

30. 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

31. 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

32. References Electrical Energy Storage for the Grid: A Battery of Choices  Science 18 November 2011Vol. 334 no. 6058 pp. 928-934

33. Questions

34. THANK YOU

36. A Comparison of New Energy Storage Methods Elliott Barr Dion Hubble Robert Piper (50 Minute Presentation)

37. 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

38. Introduction Above: Power flow throughout the day, with and without the leveling effect of energy storage Background figure adapted from: www.cntenergy.org Inset figure adapted from: en.wikipedia.org

39. 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

40. Background/motivation Power Grid Failure • 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 http://covertress.blogspot.com/2012/03/vulnerability-of-us-power-grid-centers.html

41. Background/motivation Fossil Fuels and Emissions • 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 http://www.solarfeeds.com/is-the-u-s-ditching-clean-energy-for-fossil-fuels/

42. Background/motivation Cost Considerations • 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 http://webberenergyblog.wordpress.com/2012/03/25/how-to-make-alternative-energy-affordable/

43. Background/motivation EES Systems • 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

44. Basic Principals Batteries Stores energy in electrode until external load is applied http://www.greenmanufacturer.net/article/tc/sage-supplier-lowering-costs-of-lithium-ion-batteries-for-ev-power-trains

45. Basic Principals Reduction-Oxidation Cells Stores energy in the electrolytes until an external load is applied Vanadium Redox Flow Battery http://www.pnl.gov/news/release.aspx?id=855

46. Basic Principals Super Capacitors Remember: capacitance increases with plate area. Activated carbon simply increases surface area of the plates, allowing more charge to collect Typical super capacitor with activated carbon New design with carbon nanotubes http://www.engstuff.info/2010/11/ultra-capacitors-next-generation-charge.html

47. 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

48. 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

49. 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

50. Lithium Ion Battery (cont.) • 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 http://www.sciencemag.org/content/334/6058/928.abstract