Double Layer Electrolytic CapacitorsOverviewHistory of CapacitorsElectrolytic CapacitorsHistory of Super CapacitorsCarbon AerogelSlide 7Double Layer Electrolytic Capacitors Using Activated CarbonCarbon NanotubesSlide 10Slide 11Rechargeable Batteries Vs. SupercapacitorsApplications for SupercapacitorsHybrid Electric VehiclesQuestions?Double Layer Electrolytic CapacitorsDesign Team 10Technical LectureECE_480_FS08OverviewHistory of CapacitorsElectrolytic CapacitorsHistory of SupercapacitorsDouble Layer Electrolytic CapacitorBattery vs. SupercapacitorApplication of SupercapacitorsHistory of CapacitorsIn 1740, Ewald Georg von Kleist constructed the first capacitor. In the same year Pieter von Musschenboek invented the Leyden Jar.Ben Franklin soon found out a flat piece of glass can be used in place of the jar modelElectrolytic Capacitors Two parallel plates with dielectric in betweenCapacitance limited by flat surface area and dielectric propertiesC is the capacitanceA is the area εr is the relative static permittivity (dielectric constant) εo is the permittivity of free space (8.854x10-12 F/m)d is distanceHistory of Super CapacitorsThe Electric Double Layer Capacitor effect was first noticed in 1957 by General Electric. Standard Oil of Ohio re-discovered this effect in 1966.Standard Oil of Ohio gave the licensing to NEC, which in 1978 marketed the product as a “supercapacitor”.Carbon AerogelComposed of nanometer sized particles covalently bonded togetherHigh porosity (>50% under 100 nm) Large surface area (400–1000 m²/g)- Aerogel is a low-density solid derived from gel that has had the liquid component replaced with a gas.Activated Carbon: Extremely porous with a very large surface area.Surface resembles a sponge. Area allows more electrons to be stored than other conductors. Activated Carbon ( Activated Charcoal )Double Layer Electrolytic CapacitorsUsing Activated CarbonTwo layers consisting of nanoporous electrodesSeparator is impregnated with an organic electrolyte Thin separator can only withstand low voltagesCarbon NanotubesApproximately 1/50,000th the width of a human hair Strongest and stiffest material on earth (>300 X Steal)Low density SemiconductorUnder development at MIT Replaces activated charcoal with carbon nanotubesAligned in a regular pattern that exposes greater surface areaDramatically increases effective area of electrodes Greatly increases power densityDouble Layer Electrolytic Capacitors Using Carbon NanotubesComparing Batteries & Supercapacitors- Energy density is the amount of energy stored per unit volume or mass. - Power density combines energy density with the speed that energy can be drawn out of a device.Rechargeable Batteries Vs. SupercapacitorsSupercapacitors:Higher power density Much faster charge and discharge rateEnvironmentally friendly Extremely low internal resistance or ESR High efficiency (97-98%)Over a million charge-discharge cyclesBatteries: Have higher energy density Typically 200–1000 charge-discharge cyclesContain highly reactive and hazardous chemicals Negatively effected by low temperaturesApplications for SupercapacitorsBack up for uninterruptable power supplies (UPS)Light weight power supplies for small aircraftProvide short duration power for various vehicle systems such as breaking or steeringUsed to absorb power during short periods of generation such as Regenerative BrakingExtend range and battery life in Hybrid Electric Vehicles (HEV)Hybrid Electric VehiclesThe CSIRO in Australia [national science agency] has developed the UltraBattery, which combines a supercapacitor and a lead acid battery in a single unit4x longer life cycle, 50% more power, 70% cheaper than batteries used in
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