Supercapacitor Energy StorageOrganizing principles NASA 2003 Strategic Plan Goal 3 Create a more secure world and improve the quality of life by investing in technologies and collaborating with other agencies, industry, and academia. Goal 7 Engage the public in shaping and sharing the experience of exploration and discovery. Status, Plans, Connections to NASA's Mission and Vision and to the Space Architect's Capability Requirements 1 Requirements 3.1 3.3 3.4* Requirement: electricity storage on spacecraft. Electricity storage backup systems where there is need for faster switching on and off for back up systems for the International Space Station and other satellites in low-earth orbit. Plans Plans. RuO2 supercapacitors will be refined and packaged for a variety of applications. System studies continue to show that in a hybrid application (e.g. cell phone or launch vehicle) the supercapacitor extends battery life and substantially reduces mass. Continued testing of the various applications will be done. Hypotheses & Projects Knowns and unknowns Unknown. The fundamental operation and long term durability of the supercapacitors is largely unknown. The role played by impurities in the materials isn’t understood either. Known. Supercapacitors in hybrid battery/supecapacitor systems for electromechanical actuation systems can reduce the power system mass by about 270 lbs in launch vehicle applications. For the STS, this can lead to about a 1000 lb increase in payload. 2 7.3* 10.4 Goal 10 Enable revolutionary capabilities through new technology. 10.5 10.6* * These objectives are reflected in the overall Research Partnership Program and thus not connected to specific requirements of any single research program. Requirement.: launch vehicles: energy storage. Energy storage systems that can supply short term (sec), high peak current pulses for applications such as launch vehicles, radar and communication satellites. Plans. Improved flexible packaging technology for RuO2 supercapacitors will be explored. Samples will be supplied to various application candidates. Project: SUPERCAPACITOR ENERGY STORAGE Project description. Supercapacitors store energy in the chemical valence states or in the so-called "Helmholz" double layer that exists around carbon fibers in an alkaline solution. They can provide high peak power output and can be recharged and discharged up to millions of times without damage (in contrast to batteries). Batteries are good for sustained, steady state power but not the best suited to deliver peaks of power. Supercapacitors excel at the latter but not at the former. Thus, a so-called "hybrid" system that combines batteries with supercapacitors in an application where there are many short, sharp peaks of current (such as the launch ascent of a shuttle) is ideal for a hybrid system. In supercapacitor technology, Auburn pioneered the Ni/C supercapacitor and put this technology into production at Eagle Picher (with funding support from MSFC) as the first space qualified supercapacitor. Several patents in the area of microfibrous materials were awarded for this technology. Presently the work focuses on hydrous Ruthenium Oxide (RuO2), a so-called pseudocapacitor material. This compound is being deposited by screen printing and then combined with an alkaline (KOH) electrolyte, to produces the highest capacitance to date. For example, a 3 cm diameter circle of the material that is less than 50 microns thick has over 20 Farads of capacitance at a potential of 1 V. Thus it is a very high density energy source. Status. The Ni/C supercapacitor was placed into commercial production at Eagle Picher using electrodes fabricated at Auburn and the container and assembly methods developed by Eagle Picher. The resulting package was qualified for flight and has been evaluated by MSFC. RuO2 supercapacitors technology development aims at refining the exact print ink composition and moisture content for peak energy storage and to understand possible failure mechanisms. Better hermetic sealing has been identified as a key step and new, flexible, water tight materials are being examined. Very small (2 mm diameter) flexible capacitors are being developed for the Power Sphere concept being developed by Aerospace Corp. Project site(s): Center for Space Power and Advanced Electronics, Space Research Institute, Auburn University, Auburn University, AL 36849-5320 3 4 Space Architect Perspective Capability Requirements 2.2 Space Utilities & Power 2.4 Space Assembly, Inspection, Maintenance & Servicing 2.5 Exploration and Expeditions 2.6 Space Transportation Energy Storage 2.2.5 Known. Cycle life of supercapacitors approaches 1 million cycles in contrast to batteries where the cycle life is in 10s of thousands of cycles. 5 Robotic Archetypes 2.4.8 6 Surface Systems 2.5.2 Launch Assist/Direct Launch Systems 2.6.9 OBPR Organizing Questions 4a) How can we change spacecraft systems to lessen the required upmass, volume, and power? 4e) What basic engineering research is required to enable or accelerate the deployment of the next generation space sub-systems to increase payload, crew up-mass, and power for travel beyond Low Earth Orbit? 5a) Educational outreach 5b) Public outreach Research Partnership Centers Multiple Benefits Immediate applications on Earth. Energy storage is a pervasive requirement. Supercapacitors are under development because of the large advantage they have over batteries for storage applications. Hybrid electric systems are important to improvements in vehicles like the Shuttle and its replacement where batteries teamed with supercapacitors have been demonstrated to reduce the mass of the power system by 60% or more. Leverage NASA research funds. Hybid electric vehicles, radar and communication satellites, launch vehicles, utility industry in partnership with NASA enables NASA to stretch its research dollars. 7 4. "What technology must we create to enable the next explorers to go beyond where we have been?" 8 5. "How can we educate and inspire the next generation to take the journey?" Importance: energy storage: earth. Supercapacitors can serve the utility industry by providing peak power as needed. In many simpler applications, combining a flexible supercapacitor with a battery will extend battery life and improve performance (e.g. cell phones or robots). Importance: space vehicles: energy. Energy storage is essential for all space endeavors. When solar energy is used in orbit, the necessary shadowed parts of the orbit require energy storage for the satellite to continue in operation. Whereas batteries have served the purpose well in the past, as power requirements climb, better, more efficient means have to be developed. Supercapacitors are critical for hybrid power systems such as launch vehicles. Significant mass reductions in future all-electric, hybrid launch systems compared to those using hydraulic launch systems like today’s shuttle. 9 Horn, R. E. Preliminary Thoughts on NASA Strategic Research A B C D E F G H I J K L MacroVU® Analytics M Status: Prototype V.3 10 N