Ultracapacitors for Off-Grid Solar Energy Applications

Transcription

1 Ultracapacitors for Off-Grid Solar Energy Applications Kevin C. Leonard Chief Technology Officer SolRayo LLC

2 Outline General Ultracapacitor Information Materials for Ultracapacitors Modeling Ultracapacitors for Off-Grid Solar Energy Systems

3 Introduction: Traditional Capacitors Capacitor: Device That Physically Stores Electric Charge No chemical reactions used to store charge Negative Conductive Plate Positive Conductive Plate

4 Definition of Capacitance The Ability To Hold Electric Charge C = Q/ V V Capacitance Measured in Farads, F 1 F = 1 C/V

5 What is an Ultracapacitor? Energy Storage Device 1,000,000+ Times the Capacitance of Regular Capacitors Regular Capacitor 1 μf Ultracapacitor 4F

6 How Ultracapacitors Work A = 1,000 or more m 2 /g d = Angstroms

7 Terminology Ultracapacitor Supercapacitor Electrochemical Capacitor Double Layer Capacitor Electrochemical Double Layer Capacitor All refer to the same device.

8 Ultracapacitors vs. Batteries Ultracapacitors Physical Charge Storage Higher Power Density, Faster Millions of charge/discharge cycles No maintenance Broad temperature range (-30 C to 65+ C ) Cycle efficiency can be above 95% Lower internal resistance Batteries Chemical Charge Storage Lower Power Density, Slower Thousands of charge/discharge cycles Maintenance More limited temperature range

9 Energy vs Power Energy: The Capacity to Do Work [Joules or Wh] Power: The Rate at Which Energy is Transmitted [Watts = 1J/s] High Energy Low Power Low Energy High Power

10 The Bridge Between Capacitors and Batteries Capacitors IC Engine

11 Ultracapacitor Electrode Technologies Class I High Surface Area Carbon Materials Class II Transition Metal Oxides Pseudocapacitors New Electrode Technologies New Carbon Materials Asymmetric Capacitors SolRayo s Technology

12 Class I High Surface Area Carbon Materials Typically Activated Carbon High Power Densities Cycle Life - 500,000 to 1,000,000 cycles Voltage Window Up to 2.7 V Per Cell Most Commercial Ultracapacitors Made From High Surface Area Carbon Materials For More Information on Activated Carbon See - Frackowiak, E. Carbon materials for supercapacitor application. Phys. Chem. Chem. Phys. 9, (2007)

13 Class II Transition Metal Oxides How Pseudocapacitors Work Electric charges are stored mainly in the electrode surface region by faradaic reactions Typically Made From Transition Metal Oxides

14 Types of Transition Metals Ruthenium Dioxide Very High Capacitance Reported Cycle Life of 10,000 Charge/Discharge Cycles Reported 1 More Expensive Than Carbon Typically 1 V Voltage Window Sulfuric Acid Common Electrolyte 1 and Image From Sugimoto et al. Journal of The Electrochemical Society, A255-A260 (2006)

15 New Types of High Surface Area Carbon Materials Carbon Nanotubes High Surface Area Most of it Accessible Typically Higher Conductivity Than AC Higher Power Density Than AC Potentially Expensive Ma, R.Z. et al. Study of electrochemical capacitors utilizing carbon nanotube electrodes. J. Power Sources 84, (1999) For More Information on Activated Carbon See - Niu, C.M., Sichel, E.K., Hoch, R., Moy, D., and Tennent, H. High power electrochemical capacitors based on carbon nanotube electrodes. Appl. Phys. Lett. 70, (1997)

16 Asymmetric Capacitors An Asymmetric Capacitor Replaces the Positive Carbon Electrode with Battery Type Electrode C 1 C 2 C 1 C 2 Symmetric Capacitor Asymmetric Capacitor

17 Asymmetric Capacitors Expand the Voltage Window Higher Capacitance Due to Battery Electrode Cycle Life Dependent on Battery Electrode Power Density Dependent on Battery Electrode C 1 C 2 1 = C Total C 1 C 2 If C 2 >> C 1 Then C Total " C 1 For More Information on Asymmetric Capacitors See Pell & Conway Journal of Power Sources 136 (2004)

18 SolRayo Electrode Technology Commercially Available Carbon Materials Nano Sand 2-5 nm Particles of SiO2 10 µm 10 µm

19 Isn t Nano Expensive? Nanoparticles Can Be Very Inexpensive SolRayo Nanoparticles Created by Sol-Gel Chemistry Techniques Nanoparticles Self Assemble

20 Adding Nano Sand Increases Carbon Capacitance Coating Increases Capacitance of Carbon Materials Weight Based on Carbon and Coating Weight K.C. Leonard, W.E. Suyama, and M.A. Anderson In Progress 2009

21 Cycle Life of SolRayo Materials Typical Commercial Electrochemical Capacitors lose 20% after 500,000-1,000,000 cycles These Materials Do Not Lose 20% until 1,600,000 cycles 20% Decrease at 1.6M 24% Decrease at 3M Leonard, Suyama & Anderson In Progress 2009

22 Electrochemical Capacitor Markets High Power Consumer Electronics Transportation Industrial For High Power Pulses Hybrid Electric Vehicles Renewable Energy Systems Extends Battery Life Regenerative Braking Can Use Lower Cost Batteries Electric Drive Power Steering, Seat Belt Restraints, etc.

23 Many Applications For Ultracapacitors in Renewable Energy Systems Fill-In Power For Wind and Solar Grid-Stability Power Quality Etc

24 Off-Grid Solar Energy Systems Can We Improve Stand Alone Systems By Adding Ultracapacitors??

25 Choosing The Battery Size Batteries Are Worse At Power Than Energy Capacitors POWER MUST BE USED TO SIZE BATTERIES!! IC Engine

26 Battery Ultracapacitor Hybrid System

27 Hybrid-System Equations

28 How Hybrid System Handles Pulse Power Lead Acid Battery 12 V 40 mω Internal Resistance 86.4 Wh Capacity Ultracapacitor 12 V 2.4 m Ω Internal Resistance 500 F How Does Hybrid System Handle 1800W Pulse For 5 Seconds?

29 Hybrid System No Additional Circuitry Ultracapacitor Reduces Voltage Drop in Hybrid-System

30 Ultracapacitor And Battery Working Together

31 Peak Power Enhancement

32 Off-Grid Solar Applications Off-Grid Cabin

33 Off-Grid Solar Applications Road Side Emergency Phone

34 Off-Grid Solar Applications Recreational Vehicles

35 Solar Boat? Off-Grid Solar Applications

36 Contact Information Kevin C. Leonard Chief Technology Officer SolRayo LLC