U.S. Department of Energy

Transcription

1 U.S. Department of Energy Vehicle Technologies Office Electric Vehicle Battery Research Pathways and Key Results March 21, 2017 David Howell Brian Cunningham (Presenter) Tien Duong Peter Faguy Samuel Gillard 1

2 Overview Energy Storage Funding within the Department of Energy Vehicle Technologies Office Energy Storage Overview Industry Cost Trends Technologies That Can Achieve VTO s 2022 Cost Goal VTO Roadmap Current Research Status VTO R&D Highlights Summary and Conclusions 2

3 Energy Storage Funding within DOE Energy Storage R&D Interactions at DOE Fundamental Research Transformational Research Applied Research FY16: ~$25M FY16: ~$35-40M FY16: ~$100M Office of Science Advanced Research Projects Agency Energy Vehicle Technologies Office Fundamental research to understand, predict, and control matter and energy at electronic, atomic, and molecular levels. JCESR (Hub) EFRC Core Scientific Research High-risk transformational research. BEEST (High Energy) AMPED (Battery Sensors and Controls) RANGE (Flow, Solid State, Multifunctional) IONICS (Solid State) Advanced Batteries for Vehicles Office of Electricity Delivery & Energy Reliability Grid Storage FY16: ~$20M 3

4 VTO Energy Storage R&D Overview and Strategy CHARTER: Develop battery technology that will enable large market penetration of electric drive vehicles 2022 GOAL: $125/kWh (useable) Energy Storage R&D Battery Materials Research (BMR) Applied Battery Research (ABR) Battery Development Battery Testing, Design, & Analysis 4

5 VTO Energy Storage R&D Overview and Strategy CHARTER: Develop battery technology that will enable large market penetration of electric drive vehicles 2022 GOAL: $125/kWh (useable) Energy Storage R&D Battery Materials Research (BMR) Applied Battery Research (ABR) Battery Development Battery Testing, Design, & Analysis Battery Manufacturing and Process Development 5

6 How are we doing? Rapidly falling costs of battery packs for electric vehicles, B. Nykvist and M. Nilsson; Nature, Climate Change; March 2015, DOI: /NCLIMATE2564 Production of EDV batteries doubling globally every year since % annual cost reductions for major manufacturers. Economies of scale continue to push costs towards $200/kWh. With new material chemistries and lower-cost manufacturing, cost parity with ICEs could be reached in the ten years US$/kWh 2,000 1,800 1,600 1,400 1,200 1, DOE funded projects: % conf. interval, whole industry 95% conf. interval, market leaders Publications, reports, and journals News items with expert statements Log fit of news, reports, and journals: 12 ± 6% decline Additional cost estimates without a clear method Market leader, Nissan Motors (Leaf) Market leader, Tesla Motors (Model S) Other battery electric vehicles 2012 DOE cost target $600/kWh Log fit of market leaders only: 8 ± 8% decline Log fit of all estimates: 14 ± 6% decline Future costs estimated in publications <US $150/kWh goal for commercialization 2016 DOE cost $245/kWh 2022 DOE cost target $125/kWh

7 What can get us there? 7 Cost modeling conducted on Projected Cost (100 KWh advanced battery chemistries Total Battery Pack) using the ANL BatPaC2.1 model Significant cost reductions are possible using more advanced lithium-ion materials systems Lithium-ion: Silicon based anode coupled with a high capacity cathode presents moderate risk pathway to battery systems for less than 125/kWh use Lithium metal: A higher risk pathway to generation of systems below $100/kWh use These are the best case projections assuming: Elimination of chemistry problems Courtesy: ANL BatPaC No performance limitations Assumptions of favorable system engineering are valid Realization of high-volume manufacturing

8 VTO R&D Roadmap Current emphasis: The development of high voltage cathodes and electrolytes coupled with high capacity metal alloy anodes. Research to enable lithium metal-li sulfur systems. Focus DOE EERE EV Goals: $125/kWh use Long Term Research Lithium Metal-Lithium Sulfur Lithium Air Theoretical Energy: 3000 Wh/kg, >3,000 Wh/l Silicon Anode with High-Voltage Cathode Practical Energy: Wh/kg, 800 1,200 Wh/l Smaller & Lower cost EV Battery Energy Focus DOE EERE PHEV Goals: $300/kWh use High-Voltage Cathode Practical Energy: 220 Wh/kg, 600 Wh/l Graphite/Layered Cathode Theoretical: 400 Wh/kg, 1,400 Wh/l Practical Energy: 150 Wh/kg, 250 Wh/l Achieved ~300 Cells, ~$10,000 PHEV Battery ~200 Cells, ~$3400 PHEV Battery $125/kWh use EV Battery (2022) 8

9 VTO R&D Roadmap Current emphasis: The development of high voltage cathodes and electrolytes coupled with high capacity metal alloy anodes. Research to enable lithium metal-li sulfur systems. Energy Focus DOE EERE PHEV Goals: $300/kWh use Focus DOE EERE EV Goals: $125/kWh use Long Term Research Lithium Metal-Lithium Sulfur Lithium Air Theoretical Energy: 3000 Wh/kg, >3,000 Wh/l Silicon Anode with High-Voltage Cathode Practical Energy: Wh/kg, 800 1,200 Wh/l High-Voltage Cathode Practical Energy: 220 Wh/kg, 600 Wh/l Fast Charge Graphite/Layered Cathode Theoretical: 400 Wh/kg, 1,400 Wh/l Practical Energy: 150 Wh/kg, 250 Wh/l Achieved ~300 Cells, ~$10,000 PHEV Battery ~200 Cells, ~$3400 PHEV Battery $125/kWh use EV Battery (2022) 9

10 Current Research Status for Li-ion Batteries: Advanced Cathodes Current Emphasis: Development of high Nickel NMC and mitigation of the inherent voltage fade of the Li rich layered, layered cathodes Challenges: Limited by the cathode performance materials changed little over 20 years and limited to 4.3V operation due to electrolyte oxidation at higher voltages Excess Li materials show promise but are not ready for prime time due to issues with voltage fade, high impedance, and low tap density Approach: Volts Voltage Profiles for Li-rich, Layered Cathode Understand reactivity at voltages above 4.3V and design new electrolytes, additives and inorganic coatings to protect the cathode Understand phase transformation in excess Li cathodes to design better materials Volts 10 Capacity (mah/g)

11 Advanced Cathodes: Recent Highlights Developed a new class of electrolytes based on fluorinated carbonate solvents. New electrolyte is capable of forming robust SEI on graphite anode and has reduced flammability. Delivered LiNi 0.5 Mn 1.5 O 4 /graphite coin cells w/ new F-electrolyte and retained 80% capacity after C/1C cycles (4.7V 3.5V). Developed a high throughput affordable ALD coating system that can be used to coat cathode materials. Developed 2Ah cells with ALD coated NMC 811 and graphite capable of cycles while maintaining 80% capacity retention from 4.35V 3V. Promising initial results for LNMO and graphite cycled to 5V. Developed an organosilicon material that inhibits LiPF6 breakdown. Benefits seen with 2-5% concentrations. Allows cells to operate at higher temperature and voltages. Developed LCO pouch cell with 3% organosilicon material that achieved 400 1C/1C cycles from 4.45V -3V at 45C. Double the baseline cell. 11

12 Current Research Status for Li-ion Batteries: Advanced Anodes Current Emphasis: Development of high-capacity reversible Si anode composites with good rate capability and cycle life Challenges: Large first-cycle irreversible loss Low loading/areal capacity Large capacity fade Poor coulombic efficiency Inferior rate capability Bulk Si Anode Si Nanoparticle Anode (Poor areal capacity) Approach: 12 Novel architectures: Nanotubes (NTs), Nanowires, core-shell structures, composites Functional coatings: Metals, Li + and e - conducting ceramics, carbon based systems Binders: High strength and elastomeric polymers Electrolyte additives: VC, FEC Si NTs (Scalable approach, high areal capacity >1.5 mah/cm 2 ) Source: BATT projects 100 nm Si Nanotube: HRTEM

13 Advanced Anodes: Recent Highlights Developed a 2Ah pouch cell with a novel silicon nanowire structure. 2Ah cell completed 500 DST cycles with 80% capacity retention with a beginning-of-life specific energy greater than 300Wh/kg. Will scale up their manufacturing process to enable production of 10Ah and 40Ah cells targeting 350Wh/kg at beginning-of-life. Developed a unique graphene silicon composite anode that delivers high capacity (600 mah/g), high first cycle efficiency (~85%), and >85% capacity retention at 1,000 cycles. 1,000 cycles were carried out in a prototype 2Ah pouch cell that was optimized to achieve 1,000 cycles; future efforts will focus on increased specific energy while maintaining cycle life. Developed cells w/ their CAM-7 cathode and a silicon based anode that delivers >200Wh/kg and >85% capacity retention after 1,000 cycles. Models predict chemistry could reach 220Wh/kg in state-of-theart hardware and 250Wh/kg in 15Ah pouch cells designed for PHEV applications cells are capable of >845W/kg down to 10% SOC. 13

14 Advanced Anodes: Key Technical Results 1K Current commercial cells capable of Wh/kg and cycles 14

15 Summary & Conclusions Track-record of success American-based battery factories supplying PEV batteries to multiple PEVs Cost goals met or on track to be met Clear-pathway to meet 2022 goals Major focus on advanced Lithium ion using higher voltage cathodes & intermetallic anodes Expanded work on low cost materials, electrode and cell manufacturing Technologies to go Beyond 2022 Continued focus on Li metal, sulfur electrodes and solid state electrolytes Closely coordinated with ARPA-E and the Office of Science SEM of Li 2 FeSiO 4 /C nanospheres SEM pictures of LiNi 0.5 Mn 1.5 O 4 made from MnO 2, MnCO 3 and hydroxide precursors 15

16 For More Information Brian Cunningham, Hybrid and Electric Systems, Vehicle Technologies Office U.S. Department of Energy, , 16

17 Backup 17

18 Beyond Li-ion R&D: Li Metal Anode Opportunity Dramatic increases in specific and volumetric energies possible Objectives Key technical hurdle is to prevent the gradual loss of lithium and impede dendrite formation while providing adequate power This will be addressed through: Improved understanding of the chemical and physical processes that consume lithium at the electrodeelectrolyte interface Electrolyte additives to prevent dendritic Li growth Engineering barrier materials, solid or composite electrolytes to stabilize the anode-electrolyte interface Before cycling (with SEI layer) 10 cycles Evolution of an SEI Layer on Cycling of a Metallic Lithium Electrode (scale bars represent 100 microns) 18

19 Li Metal Anode: Recent Highlight Reduced Graphene Oxide with Nanoscale Interlayer Gaps as Stable Host for Li Metal Anodes Cross-section view Pristine GO film Top view: After 10 cycles, the surface is smooth without Li dendrites Sparked rgo film Li-rGO composite 19 Y. Cui group, Nature Nanotechnology (2016) DOI: /NNANO

20 Cycling of Li Reduced Graphene Oxide Electrodes Y. Cui group, Nature Nanotechnology (2016) 20

21 Beyond Li-ion R&D: Sulfur Electrode Barriers Formation/dissolution of polysulfides Sluggish kinetics of subsequent conversion of polysulfides to Li 2 S High diffusivity of polysulfides in the electrolyte Insulating nature or poor conductivity of sulfur/li 2 S Volumetric expansion/contraction of sulfur Approaches Identify basic mechanisms using in situ-epr and NMR studies Explore sulfide, selenide and oxide composite electrodes showing cycling up to 300 cycles Use of lithium-ion conductor coatings and matrices showing low fade rates (<0.003% per cycle) Mesoscale modeling to understand polysulfide mechanisms 21 Specific capacity improvement by use of oxide composite electrodes upon prolonged 300 charge-discharge cycles at 0.5C Minimum energy path for lithium ion diffusion on oxide surfaces and (f) Potential energy profiles for Li + diffusion along different adsorption sites Nanoporous CFM containment and improvement in cycling stability when tested at C/6 rate

22 Beyond Li-ion R&D: Solid Electrolytes Barriers Not all are stable against lithium Have relatively poor ionic conductivity at room temperatures Exhibit inherently very large interfacial impedance Brittle and difficult to fabricate Approaches Perform mechanical studies through state-of-the-art nano-indentation techniques to probe the surface properties of the solid electrolyte and the changes occurring to lithium Develop composite electrolytes (polymer and ceramic electrolytes) and investigate lithium ion transport at the interface to determine the effective ionic conductivity Identify the correlation between defect types and the current density limit in Garnetbased electrolytes Computationally and experimentally study the interfacial structure-impedance relationship in Garnet-based electrolytes to design new materials 22