The Challenges of Electric Energy Storage. Nigel Taylor, Nick Green, Chris Lyness, Steve Nicholls

Transcription

1 The Challenges of Electric Energy Storage Nigel Taylor, Nick Green, Chris Lyness, Steve Nicholls

2 Technology Walk Customer familiarity with recharging IC HEV PHEV EV Kinetic energy recovery Plug-in Battery Charging Improving Battery Technology 2

3 Power Demand Average power demand is low ~3.3kW Without any regen, average power demand ~5kW This is an average over 1200s 1200*5*1000 = 6MJ ~ 1.67kWh Distance = 10.77km -> 155Wh/km Maximum power ~40kW Maximum regen ~27kW Average ~3.3kW 3

4 Real World Energy Use Real World driving increases energy demand ~15% More opportunity for braking regeneration Also brings with it higher system loads and heating and cooling loads 4

5 How much energy? 155 x 1.15 = 178Wh/km 400 miles = 644km 644 x 178 = Wh ~115kWh So that s a useable 115kWh 23% conversion efficiency = 165 kwh Electricity 70% conversion efficiency 40% conversion efficiency = 8.75 kg Hydrogen 380litres = 42 kg Gasoline 56litres 130 kg CO 2 tailpipe + 23kg WTT 0 kg CO 2 tailpipe + pathway ~ 80kg CO 2 (current EU ave) 80kg CO 2 And getting better! 0 kg CO 2 tailpipe + pathway CO kg onsite electrolysis, 109kg local NG reforming kg CO 2 150kg CO 2 5

6 Energy Storage Options Battery Super-capacitor Diesel Petrol Flywheel Compressed air Hydraulic Liquid air Hydrogen Hydroelectric PCM SMES Methane 6

7 EV versus Hydrogen Pathways Vehicle Power Lines Efficient Battery Charger Efficient Li-ion Batteries Efficient Drivetrain Efficient ~150kWh from Renewables Electric Motor 115kWh to Wheels Vehicle Electrolysis H 2 Gas pipeline Efficient H 2 Storage & Fuel Cell System 40% Efficient Electric Drivetrain Efficient >500kWh from Renewables Pressurising Pressurising Battery/ Supercap 115kWh to Wheels 7

8 Start with the highest energy material Li-ion Spirally wound Lead acid NiCd Lead Acid Li-Ion NiCd Zinc Air NiMh Li-Polymer (Li-ion(ish) Li-polymer Spiral Wound Pb W/kg Zn-air Lead Acid Ni-MH Wh/kg 8

9 Battery hydrogen gas or liquid natural gas (methane, CH4) gasoline butter alcohol (ethanol) coal chocolate chip cookies modern High Explosive (PETN) TNT (the explosive trinitrotoluene) Alkaline flashlight battery Li-ion computer battery W/kg Lead Acid NiMh Li-Ion Li-polymer Lithium Managanese Dioxide - Non-Rech NiCd Spiral Wound Pb Series8 12V lead acid battery Wh/kg Energy Density [kwh/kg] 9

10 Pack Sizing 115kWh useable energy Charge / discharge curves Drive cycles Usage cycles Ambient conditions Maximum current <- inverter design Voltage range -> inverter design 10

11 Pack Sizing #S#P V L, I L 11

12 Total Pack Size Usable = 115kWh Total = 135kWh Mass of cells = 580kg Mass of battery pack ~ 800kg Maybe 400 miles is too much? Power demand too high? How did it grow from 580kg to 800kg What other chemistry options do I have? When does this become achievable? 12

13 Why the Cost & limited range? 4x cost increase 2x cost increase * $66/kWh LiNi 0.33 Mn 0.33 Co 0.33 O 2 $295/kWh EV cell * $663/kWh Total pack * kwh/kg LiNi 0.33 Mn 0.33 Co 0.33 O kwh/kg EV cell Wh/kg (total) (Nissan Leaf) *Lowe, Tokuoka, Trigg & Gereffi; % Energy density reduction 50% Energy density reduction 13

14 Why is packaging cells so inefficient? High Voltage wiring harness High voltage isolation system Sensor systems Heating system? Mechanical Harness Battery control module Cooling system Low voltage wiring harness 14

15 What factors do we have to design around? 3 areas of failure modes for battery Performance Temperature (<-0 0 C) voltage High Current Long pulse time Durability and robustness High temp cycle High temp Key off Large No. cycles High Voltage Wide voltage window Storage time Vibration High voltage storage Safety Over voltage Over Dis/charge Temperature Deformation Internal short circuit External short circuit Low voltage storage 15

16 What happens next? Cell component Technology Data Modified from Fraunhofer report: Innovationsallianz Lithium Ionen Batterie LIB 2015 and Thackeray presentation & included some recent academic findings Anode Cathode 10 X 2012 energy density Electrolyte Separator Modif Graphite Soft Carbon Si-Nanotubes Li-Metal Si Alloy C/alloy composites Β-TiO 2 Li 4 Ti 5 O 12 Oxide anodes Cu 6 Sn 5 Non-Si Alloy Li-air? LiFePO Li 4 LiNiXXO 2 2 FeSiO 4 Sulfur -SO 4 F LiMn 2 O 4 LL-NMC Li(MnNi) 2 O 4 Conversion Air/Carbon LiNi 0.3 Mn 0.3 Co 0.3 O 2 Li(MnNi)PO 4 Blends cathodes Zn-air? Li 5 FeO 4 Additives Gel-polymer 5V electrolyte LiPF 6 free Polymer Li-Sulfur? membrane Chemically impregnated Current Li-ion Li-ion optimisation Cellulose Casted separator Solid electrolyte 2 X 2012 energy density New battery systems Casing 2012 energy density 5V battery W/ Titanate anode Battery W/ high cap anode Al Laminate High surface area current collector Current collector as cell housing Li-polymer battery 5V cell Li-ion Chemistry Li-sulfur battery Battery W/Li metal anode Li-solid electrolyte Battery W/ High cap cathode Li-air Post Li-ion Chemistry 16

17 The Challenges of Electric Energy Storage Electrochemical battery is primary choice for electric energy storage Electrochemistry has evolved a long way in 10 years. Multidisciplinary teams are evolving that can solve the research, design, engineering and manufacturing challenges. Cell engineering is having significant impact on pack engineering requirements. Future cell chemistry development is opening up some exciting options. 17