Supercapacitors for EV and GridScale Energy Storage Silverberg

Supercapacitors for EV and Grid-Scale Energy Storage Silverberg 8 Oct 2015

Outline • Context – Why do we need energy storage? – What is a supercapacitor? – What can supercapacitors do for us? • Research: Graphene supercapacitors • Industry: Sunvault, Maxwell, Volvo

Functions for Energy Storage • Portable electronics (5 -100 Wh, <50 cm 3) • Transport (50 – 100 k. Wh, 500 kg) main, regenerative, start/stop • Grid-scale (MWh, cost) meeting peak load, smoothing renewable

Grid-Scale Energy Storage Do. E, 2013

Key Metrics for Comparison *Cycle life

Electric Vehicle Energy Storage Li-ion battery

Key Metrics for Comparison *Energy density Zhang et al. 2015

Capacitor •

Supercapacitor • Energy density increase to ~5 -10 Wh/kg

Battery vs. Capacitors Li-ion Battery Capacitor Supercapacitor Charge Time 600 s 0. 001 s 10 s Cycle Life 1000 500, 000 Specific Energy 150 Wh/kg 0. 01 Wh/kg 5 Wh/kg Specific Power 1 k. W/kg 10 k. W/kg Energy Cost $1/Wh $5000/Wh $20/Wh 10 k. W/kg

Solar Power Smoothing

Solar Power Smoothing UCSD microgrid provides 90% of campus power 22 k. W CPV with 2. 5 k. Wh supercap Scale of problem is TBD

Regenerative Braking ARTEMIS by INRETS

Regenerative Braking

Regenerative Braking Philadelphia SEPTA subway 10 -30% reduction in grid-use Also acts as grid storage

Future Application: EV/Small Grid-Scale Storage Li-ion Battery Capacitor Supercapacitor Charge Time 600 s 0. 001 s 10 s Cycle Life 1000 500, 000 Specific Energy 150 Wh/kg 0. 01 Wh/kg 5 Wh/kg Specific Power 1 k. W/kg 10 k. W/kg Energy Cost $1/Wh $5000/Wh $20/Wh 10 k. W/kg

Graphene Specific Capacitance Specific Energy

Energy Density is the key Graphene, theory Graphene, expt Zhang et al. 2015 Theoretical single layer graphene: over 100 Wh/kg

Specific Capacitrance (F/g) Graphene supercapacitors 600 500 400 300 >100 Wh/kg GSCs Typical Supercapacitor Graphene Theoretical 200 100 0 200720082009201020112012201320142015 Year

Graphene supercapacitors @ UCLA https: //vimeo. com/51873011

Graphene supercapacitors @ UCLA

Sun. Vault http: //www. sunvaultenergy. com/web 20/video-updates/ • “The company has had 4 different names since 2010 and 2 different business lines. • There is little technical detail in the company's press releases and website to support its claims. • The majority of the company's stock is held by third parties with little information available on them. ” – Seeking Alpha “A company no one has ever heard of is using technology no one has ever heard of to make a car with 1, 000 lb-ft of torque that will blow the doors off any Tesla, Ferrari or Mc. Laren every made. And it will be ready in 6 months. ” –Ecomento “Sunvault Energy Inc (OTCMKTS: SVLT) Stock Surges For No Apparent Reason” - Hot. Stocked

Volvo Energy Panels, 2013

Maxwell & GM Partnership, Sep 2015 Start-stop technology

Outlook • Continued use for high power, low energy applications – Regen braking – Start/stop – High-frequency smoothing • With further energy density improvements – EV power – Larger grid-scale applications

Supp: Parameters for Supercap Optimization