ECEN5017 Guest Lecture Overview of NREL Battery Lifetime Overview of NREL Battery Lifetime Models & Health Management R&D for Models & Health Management R&D for Electric Drive Vehicles Electric Drive Vehicles Kandler Smith [email protected]Ahmad A Pesaran Ahmad A. Pesaran [email protected]Center for Transportation Technologies and Systems National Renewable Energy Laboratory NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. National Renewable Energy Laboratory September 2012
35
Embed
Overview of NREL Battery Lifetime Models & Health ...ecee.colorado.edu › ~ecen5017 › lectures › CU › L17_out.pdf · Overview of NREL Battery Lifetime Models & Health Management
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
ECEN5017 Guest Lecture
Overview of NREL Battery Lifetime Overview of NREL Battery Lifetime Models & Health Management R&D for Models & Health Management R&D for ggElectric Drive VehiclesElectric Drive Vehicles
Center for Transportation Technologies and Systems National Renewable Energy Laboratory
NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
National Renewable Energy Laboratory
September 2012
NREL EDV Energy Storage ProjectsSupporting DOE and industry achieve energy storage targets for electrified vehicles pp g y gy g g
Battery Material Research and Development Battery Material Research and Development
Component Testing and Characterization (Including Safety)Component Testing and Characterization (Including Safety)
Mostly formed during first cycle of battery but continues to grow at slow rateMostly formed during first cycle of battery, but continues to grow at slow rateMay penetrate into electrode & separator pores, inhibiting Li transport in the electrolyteHigh temperature effectsHigh temperature effects
– Exothermic side reactions cause self heating– Film breaks down and dissolves, later precipitates
More stable inorganic SEI formed blocking Li insertion– More-stable inorganic SEI formed, blocking Li insertionLow temperature effects (during charging)
– Slow diffusion causes Li saturation at LixC6 surface– Slow kinetics causes increased overpotential
NATIONAL RENEWABLE ENERGY LABORATORY
– Slow kinetics causes increased overpotential
Anode Aging
2. Changes of Active Material
Volume changes during insertion/de-insertion (~10%)Solvent intercalation, electrolyte reduction, gas evolution , y , ginside LixC6
Stress Cracks
3. Changes of Composite Electrode
SEI & volume changes cause: – contact loss between LixC6, conductive binder, and current
collector– reduced electrode porosity
NATIONAL RENEWABLE ENERGY LABORATORY
Anode Aging
NATIONAL RENEWABLE ENERGY LABORATORY
Image: Vetter et al., “Ageing mechanisms in lithium‐ion batteries,” J. Power Sources, 147 (2005) 269‐281
Cathode Aging
Li(Ni,Co,Al)O2 MaterialsLiC O th d t i lLiCoO2 common cathode materialLiNiO2 structure unstable unless
doped with Co or AlLi(Ni,Co,Al)O2 volume changes ( , , ) 2 g
are small good cycle lifeDischarged state stable at high
Surface effectsSEI film formation accelerated when charged > 4 2 V high temperatures
Image: Vetter et al., “Ageing mechanisms in lithium‐ion batteries,” J. Power Sources, 147 (2005) 269‐281
– SEI film formation accelerated when charged > 4.2 V, high temperatures– Electrolyte oxidation and LiPF6 decomposition– Li(Ni,Co,Al)O2 source O2 rock-salt structure with low electronic conductivity & Li
diffusion– Gas evolution
NATIONAL RENEWABLE ENERGY LABORATORY
Gas evolution
Cathode Aging
Source: Vetter et al., “Ageing mechanisms in lithium‐ion batteries,” J. Power Sources 147 (2005) 269‐281Power Sources, 147 (2005) 269 281
Source: Wohlfahrt‐Mehrens et al., “Aging mechanisms of lithium cathode materials,” J. Power Sources, 127 (2004) 58‐64
NATIONAL RENEWABLE ENERGY LABORATORY
Summary of AgingA i i fl d bAging influenced by:Both high and low SOCHigh temperaturesHigh temperaturesLow temperatures during chargingSurface chemistry (anode and cathode)Su ace c e st y (a ode a d cat ode)Phase transitions/structural changes (cathode)
Both calendar life (years) and cycle life (driving and charging patterns) are important
NATIONAL RENEWABLE ENERGY LABORATORY
How Can We Predict Battery Life?
Accelerated storage testsRelatively well understoodMechanism: SEI growth, Li lossModel:
1.25
1.3
1.35
stan
ce
304047.555
Calendar Life Study at Various T (°C)
Model:– t½ time dependency– Arrhenius T dependency
Phoenix, AZ ambient conditions33 miles/day driving, 2 trips/day
NATIONAL RENEWABLE ENERGY LABORATORY
Battery R&D
•Energy storage is already ubiquitous in electronics; many more vehicle and grid applications are in the pipeline
• Cost life and safety all need improvement for greater marketCost, life, and safety all need improvement for greater market acceptance
•Multi-disciplinary, multi-physics nature of batteries:• Slow development process• Slow development process• Moore’s Law does not apply• Easier to find a thesis topic!
•Student opportunities at NREL• Part-time test engineer; send resumes to [email protected]• Organize a thesis topic together with NREL