Electrical Energy Storage for Electrical Energy Storage for Electrical Energy Storage for Electrical Energy Storage for Vehicles: Targets and MetricsVehicles: Targets and MetricsVehicles: Targets and MetricsVehicles: Targets and Metrics

Ted J. Miller

November 3 2009

Key Automotive Targets• HEV (40kW battery full hybrid system example)

– High specific power: >2,000W/kg (<20kg battery)– -30C cranking capability: 5kW– Extremely high shallow cycle life: 500k cycles– Long operating life: 15 years– High power/energy ratio: >20:1– Cost: goal of $20/kW ($800) @ 100k/year

• PHEV (Ford Escape Plug-in Hybrid battery system example)– Higher energy power battery: 10kWh / 25mi / 140kg / 95 liters– Requires full power over a wide temperature range– Both high deep (5,000) and shallow (500k) cycle life required– Must be fully abuse tolerant when packaged in the crash zone– Power/energy ratio: 5:1 to 15:1– Cost: $1,000/kWh ($10-15k); goal = $200-300/kWh @100k/year

• EV (30kWh electric vehicle battery system example) – High energy density: >120Wh/kg (30kWh / 100mi / 250kg battery)– High deep discharge cycle life: 3,000 cycles to 80-90% DOD– Power/energy ratio: 2:1 to 4:1– Cost: $600/kWh ($18k) at volume; future high volume prospect = $300/kWh

• HEV (40kW battery full hybrid system example)– High specific power: >2,000W/kg (<20kg battery)– -30C cranking capability: 5kW– Extremely high shallow cycle life: 500k cycles– Long operating life: 15 years– High power/energy ratio: >20:1– Cost: goal of $20/kW ($800) @ 100k/year

• PHEV (Ford Escape Plug-in Hybrid battery system example)– Higher energy power battery: 10kWh / 25mi / 140kg / 95 liters– Requires full power over a wide temperature range– Both high deep (5,000) and shallow (500k) cycle life required– Must be fully abuse tolerant when packaged in the crash zone– Power/energy ratio: 5:1 to 15:1– Cost: $1,000/kWh ($10-15k); goal = $200-300/kWh @100k/year

• EV (30kWh electric vehicle battery system example) – High energy density: >120Wh/kg (30kWh / 100mi / 250kg battery)– High deep discharge cycle life: 3,000 cycles to 80-90% DOD– Power/energy ratio: 2:1 to 4:1– Cost: $600/kWh ($18k) at volume; future high volume prospect = $300/kWh

USABC HEV Battery RequirementsFreedomCAR Goals Power-Assist Power-Assist

Characteristics Units Minimum MaximumPulse Discharge Power (10s) kW 25 40

Max Regen Pulse (10s) kW 20 (50Wh pulse) 35 (97Wh pulse)

Total Available Energy kWh 0.3 0.5

Round Trip Efficiency % >90 - 25Wh Cycle >90 - 50Wh Cycle

Cycle Life for specified SOC Increments Cyc. 300k 25Wh Cycle (7.5 MWh) 300k 50Wh Cycle (15 MWh)

Cold-cranking Power at -30°C (Three 2-sec pulses, 10-sec rests between)

kW 5 7

Calendar Life Yrs 15 15

Max Weight kg 40 60

Max Volume liters 32 45

Production Price @ 100k units/yr $ 500 800

Maximum Operating Voltage Vdc ≤ 400 Max ≤ 400 max

Minimum Operating Voltage Vdc ≥ 0.55xVmax ≥ 0.55 x Vmax

Maximum Self Discharge Wh/d 50 50

Operating Temperature °C -30 to +52 -30 to +52

Survival Temperature °C -46 to +66 -46 to +66

FreedomCAR Goals Power-Assist Power-Assist

Characteristics Units Minimum MaximumPulse Discharge Power (10s) kW 25 40

Max Regen Pulse (10s) kW 20 (50Wh pulse) 35 (97Wh pulse)

Total Available Energy kWh 0.3 0.5

Round Trip Efficiency % >90 - 25Wh Cycle >90 - 50Wh Cycle

Cycle Life for specified SOC Increments Cyc. 300k 25Wh Cycle (7.5 MWh) 300k 50Wh Cycle (15 MWh)

Cold-cranking Power at -30°C (Three 2-sec pulses, 10-sec rests between)

kW 5 7

Calendar Life Yrs 15 15

Max Weight kg 40 60

Max Volume liters 32 45

Production Price @ 100k units/yr $ 500 800

Maximum Operating Voltage Vdc ≤ 400 Max ≤ 400 max

Minimum Operating Voltage Vdc ≥ 0.55xVmax ≥ 0.55 x Vmax

Maximum Self Discharge Wh/d 50 50

Operating Temperature °C -30 to +52 -30 to +52

Survival Temperature °C -46 to +66 -46 to +66

FreedomCAR GoalsFreedomCAR Goals Power-AssistPower-Assist Power-AssistPower-Assist

CharacteristicsCharacteristics UnitsUnits MinimumMinimum MaximumMaximumPulse Discharge Power (10s)Pulse Discharge Power (10s) kWkW 2525 4040

Max Regen Pulse (10s)Max Regen Pulse (10s) kWkW 20 (50Wh pulse)20 (50Wh pulse) 35 (97Wh pulse)35 (97Wh pulse)

Total Available EnergyTotal Available Energy kWhkWh 0.30.3 0.50.5

Round Trip EfficiencyRound Trip Efficiency %% >90 - 25Wh Cycle>90 - 25Wh Cycle >90 - 50Wh Cycle>90 - 50Wh Cycle

Cycle Life for specified SOC IncrementsCycle Life for specified SOC Increments Cyc.Cyc. 300k 25Wh Cycle (7.5 MWh)300k 25Wh Cycle (7.5 MWh) 300k 50Wh Cycle (15 MWh)300k 50Wh Cycle (15 MWh)

Cold-cranking Power at -30°C (Three 2-sec pulses, 10-sec rests between)Cold-cranking Power at -30°C (Three 2-sec pulses, 10-sec rests between)

kWkW 55 77

Calendar LifeCalendar Life YrsYrs 1515 1515

Max WeightMax Weight kgkg 4040 6060

Max VolumeMax Volume litersliters 3232 4545

Production Price @ 100k units/yrProduction Price @ 100k units/yr $$ 500500 800800

Maximum Operating VoltageMaximum Operating Voltage VdcVdc ≤ 400 Max≤ 400 Max ≤ 400 max≤ 400 max

Minimum Operating VoltageMinimum Operating Voltage VdcVdc ≥ 0.55xVmax≥ 0.55xVmax ≥ 0.55 x Vmax≥ 0.55 x Vmax

Maximum Self DischargeMaximum Self Discharge Wh/dWh/d 5050 5050

Operating TemperatureOperating Temperature °C°C -30 to +52-30 to +52 -30 to +52-30 to +52

Survival TemperatureSurvival Temperature °C°C -46 to +66-46 to +66 -46 to +66-46 to +66

USABC PHEV Battery GoalsCharacteristics at EOL (End of Life) High Power/Energy Ratio

Battery High Energy/Power Ratio

BatteryReference Equivalent Electric Range miles 10 40Peak Pulse Discharge Power - 2 Sec / 10 Sec kW 50 / 45 46 / 38Peak Regen Pulse Power (10 sec) kW 30 25Available Energy for CD (Charge Depleting) Mode, 10 kW Rate kWh 3.4 11.6Available Energy for CS (Charge Sustaining) Mode kWh 0.5 0.3Minimum Round-trip Energy Efficiency (USABC HEV Cycle) % 90 90Cold cranking power at -30°C, 2 sec - 3 Pulses kW 7 7

CD Life / Discharge Throughput Cycles/MWh 5,000 / 17 5,000 / 58

CS HEV Cycle Life, 50 Wh Profile Cycles 300,000 300,000Calendar Life, 35°C year 15 15Maximum System Weight kg 60 120Maximum System Volume Liter 40 80Maximum Operating Voltage Vdc 400 400Minimum Operating Voltage Vdc >0.55 x Vmax >0.55 x VmaxMaximum Self-discharge Wh/day 50 50

System Recharge Rate at 30°C kW 1.4 (120V/15A) 1.4 (120V/15A)

Unassisted Operating & Charging Temperature Range °C -30 to +52 -30 to +52

Survival Temperature Range °C -46 to +66 -46 to +66

Maximum System Production Price @ 100k units/yr $ $1,700 $3,400

Requirements of End of Life Energy Storage Systems for PHEVs

USABC EV Battery GoalsParameter (units) of fully burdened system

Mid-Term Goal

Minimum Goals for Long Term Commercialization

Long Term Goal

Power Density (W/liter) 250 460 600 Specific Power - Discharge, 80% DOD/30 sec. (W/kg)

150 300 400

Specific Power - Regen, 20% DOD/10 sec. (W/kg)

75 150 200

Energy Density - C/3 Discharge rate (W•h/liter)

135 230 300

Specific Energy - C/3 Discharge rate (W•h/kg)

80 150 200

Specific Power/Specific Energy Ratio

2:1 2:1 2:1

Total Pack Size (kW•h) 40 40 40 Life (Years) 5 10 10 Cycle Life - 80% DOD (Cycles)

600

1000 to 80% DOD 1600 to 50% DOD 2670 to 30% DOD

1000

Power & Capacity Degradation (% of rated spec)

20 20 20

Ultimate Price - 10,000 units @ 40 kW•h ($/kW•h)

150 <150 ($75/kWh Desired)

100

Operating Environment (°°°°C)

-30 to +65

-40 to +50 20% Performance Loss (10%

desired)

-40 to +85

Normal Recharge Time (hours) 6 6 (4 desired)

3 to 6

High Rate Charge

40-80% SOC in 15

minutes

20-70% SOC in <30 minutes @ 150W/kg

(<20min @ 270W/kg desired)

40-80% SOC in 15

minutes Continuous discharge in 1 hour - No failure (% of rated capacity)

75 75 75

USABC Energy Storage GoalsFreedomCAR Energy Storage Goals

Characteristics Units Start-Stop M-HEV P-HEV Low Power High Power Low Power High

Power Comm. Long Term

Discharge Power kW 6 for 2 sec 13 13 for 10 sec 25 for 10 sec 40 25 for 10 sec 50Specific Power-Dischg 80% DOD/30 sec W/kg 300 400Regen Pulse kW N/A 8 for 2 sec 18 20 for 10 sec 35 30 for 5 sec 60Specific Power-Regen 20% DOD/10 sec W/kg 150 200Engine-off Accessory Load kWRecharge Rate kW 2.4 2.6 4.5Power Density W/l 460 600Available Energy Wh 250 @ 3kW 300 700 300 500 1500 3000Specific Energy - C/3 Discharge Rate Wh/kg 150 200Energy Density - C/3 Discharge Rate Wh/l 230 300Specific Power/Specific Energy RatioTotal Pack Size kWhEnergy Efficiency on Load Profile %Cycle Life (to specific usage profiles) cycleCalendar Life yearCold-start at -30C kW 5 for 2 sec 7Maximum Weight kg 10 25 35 40 60 40 65Maximum Volume liter 9 20 28 32 45 32 50Production Price at 100k units/year $US 150 260 360 500 800 500 1000Production Price at 10k units/year $/kWh 150 100Maximum Operating Voltage VdcMinimum Operating Voltage VdcMaximum Self-discharge Wh/dOperating Temperature Range C -30-+65 -40-+85Survival Temperature Range C

-30 to +52-46 to +66

-30 to +52-46 to +66

-30 to +52-46 to +66

>0.55xVmax27 >0.55xVmax5020 50

8 at 21V minimum for 2 sec 5 for TBD min

40048 440

2:140

1515 15 10300k450k TBD 1000-80% DOD

3 for 5 min

9090 90

HEV (Power-Assist)42-Volt Fuel Cell Vehicle Battery EV

Automotive Battery Electrochemistry• Present and near-term designs

• Future designs– Higher power, higher energy, lower cost

lithium ion– High energy metallic lithium

• Present and near-term designs

• Future designs– Higher power, higher energy, lower cost

lithium ion– High energy metallic lithium

Type Abbrev. Potential Anode Separator Cathode Electrolyte Key Attributes

lead-acid PbA 2.0V lead polyolefin glass mat lead-oxide sulfuric acid high power

low costnickel/metal-

hydride NiMH 1.2V metal-hydride alloy polypropylene nickel-oxide potassium

hydroxidelong life durability

lithium-ion Li-Ion 3.6V 2.4V

carbon lithium-titanate polyolefin

metal-oxide metal-

phosphate

carbonates and lithium salt

high energy design flexibility

lithium-polymer Li-Poly 3.6V 2.4V

carbon lithium-titanate polyolefin metal-oxide cabonates, lithium

salt, and ploymerhigh energy

planar design

HEV Battery AdvancementEscape Battery Module

Fusion HEV Battery Pack

Cell Count - 17%

Weight - 23%

Cell Power +28%

Escape HEV Battery Pack

Fusion Battery Module

Advanced Automotive Batteries

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Fuel Energy Density

Gasoline

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Li-Ion Battery

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Evolutionary vs. Revolutionary

(M. Winter - University of Münster)

EV Battery Cost• USABC long term goal of $100/kWh

– 40kWh battery system assumed ($4k)– $150/kWh commercialization target

• Consumer secondary cell cost of $300/kWh• Achieving a battery cost of less than $10k

– High volume cost prospect is $300/kWh– Long term potential to $250/kWh– Resulting energy is 33-40kWh– EV range of 100-200 miles

• 500 mile range would require at least 100kWh– USABC long term cost goal would need to be achieved– Much higher energy density (Wh/liter) a critical must– Charger and infrastructure power require ≥≥≥≥ 3x upgrade

• USABC long term goal of $100/kWh– 40kWh battery system assumed ($4k)– $150/kWh commercialization target

• Consumer secondary cell cost of $300/kWh• Achieving a battery cost of less than $10k

– High volume cost prospect is $300/kWh– Long term potential to $250/kWh– Resulting energy is 33-40kWh– EV range of 100-200 miles

• 500 mile range would require at least 100kWh– USABC long term cost goal would need to be achieved– Much higher energy density (Wh/liter) a critical must– Charger and infrastructure power require ≥≥≥≥ 3x upgrade

Production EV Battery Examples• Ford EV

– 23kWh battery and 100 mile range

• Mitsubishi MiEV– 16kWh battery and 100 mile range

• Nissan Leaf– 25kWh battery and 100 mile range

• BMW Mini EV– 35kWh battery and 150 mile range

• Ford EV– 23kWh battery and 100 mile range

• Mitsubishi MiEV– 16kWh battery and 100 mile range

• Nissan Leaf– 25kWh battery and 100 mile range

• BMW Mini EV– 35kWh battery and 150 mile range

Food for thought . . .• Circa 1991 USABC EV battery price goal

determination– ICE cost competitiveness assumed– Average 1991 gas price was $1.10/gal.– Resultant USABC EV battery price goal was $100/kWh

• A generalized formula of $100/kWh of battery per $1.10/gallon of gasoline may be assumed– Average October 2009 gas price is $2.72/gallon– Resultant battery price is $250/kWh

• This is slightly less than the present commodity price for consumer (laptop, cell phone, PDA, etc.) Li-Ion batteries

• Bottom line: Threshold may have been reached which makes battery energy storage a viable option

• Circa 1991 USABC EV battery price goal determination– ICE cost competitiveness assumed– Average 1991 gas price was $1.10/gal.– Resultant USABC EV battery price goal was $100/kWh

• A generalized formula of $100/kWh of battery per $1.10/gallon of gasoline may be assumed– Average October 2009 gas price is $2.72/gallon– Resultant battery price is $250/kWh

• This is slightly less than the present commodity price for consumer (laptop, cell phone, PDA, etc.) Li-Ion batteries

• Bottom line: Threshold may have been reached which makes battery energy storage a viable option

But, predictability is poorU.S. Gasoline Price (1990-2009)

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Automotive Adoption MetricsHierarchy of Needs:

1. Must work• Performance, life and robustness

2. Must fit (Wh/liter)• Package without compromising crash performance

and expected interior utility3. Must be cost effective

• Life of vehicle performance• Cost of fuel influence• Cost of carbon influence• Value based on power and/or energy density• Value based on degree of uniformity

4. Must be mass effective (Wh/kg and W/kg)

Hierarchy of Needs:1. Must work

• Performance, life and robustness2. Must fit (Wh/liter)

• Package without compromising crash performance and expected interior utility

3. Must be cost effective• Life of vehicle performance• Cost of fuel influence• Cost of carbon influence• Value based on power and/or energy density• Value based on degree of uniformity

4. Must be mass effective (Wh/kg and W/kg)

t1

What will be most valued?• Hybrids

– Power density and retained energy• NiMH > 4,000W/liter and 140Wh/liter• Li-Ion > 6,000W/liter and 150Wh/liter

– Increase power density valued• 8 - 10kW/liter with at least 150Wh/liter

• Plug-in Vehicles– Energy density and power retained

• Li-Ion > 300Wh/liter and > 1,000W/liter– Increased energy density valued

• 500 – 600Wh/liter with at least 1,000W/liter

• Hybrids– Power density and retained energy

• NiMH > 4,000W/liter and 140Wh/liter• Li-Ion > 6,000W/liter and 150Wh/liter

– Increase power density valued• 8 - 10kW/liter with at least 150Wh/liter

• Plug-in Vehicles– Energy density and power retained

• Li-Ion > 300Wh/liter and > 1,000W/liter– Increased energy density valued

• 500 – 600Wh/liter with at least 1,000W/liter

Ford Li-Ion Battery Research

Electrochemical Modeling(10C Discharge Pulse Results @ intermediate SOC)

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Distance from Cu foil, microns

LiPF

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ol/l

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46 s0 s and >100 s

42 s

60 s

40.6 s

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1 s

5 s

10.2 s

Negative Separator Positive

(D. Bernardi - Ford)

Li-Ion Electrode Degradation• Electrode degradation studies via Raman• Surface and cross section mapping• In-situ characterization during cell cycling

• Electrode degradation studies via Raman• Surface and cross section mapping• In-situ characterization during cell cycling

00.20.40.60.811.21.41.61.822.22.42.62.8

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(J. Remillard and J. Nanda - Ford)

Lithium Intercalation Model• First principles model of graphite voltage vs. staging• Explains limited ion mobility at high vs. low Li conc.• First principles model of graphite voltage vs. staging• Explains limited ion mobility at high vs. low Li conc.

Equilibrium, increased and decreased graphite interlayer distance at beginning of charge

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inter-plane distance -10%

inter-plane distance +10%

+/- 10%

Equilibrium, increased and decreased graphite interlayer distance at beginning of charge

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inter-plane distance -10%

inter-plane distance +10%

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Li diffusion between two Li sites at end

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Li diffusion between two Li sites at end

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(G. Ceder, et al. – MIT)

High Energy Battery Research• High Energy Li-Ion Composite Anode

– Silicon-carbon material– Potential to double existing capacity

• Lithium-Air (Oxygen) Technology– Metallic lithium plating model– Lithium plating modeling, experimentation and validation– O2 cathode catalyst synthesis and characterization– High throughput materials investigations– Air electrode design and analysis– Large format cell design evaluation

• Solid State Battery Technology– Solid state electrode conduction and ionic conductivity

experimentation and analysis– Predictive model development and validation

• High Energy Li-Ion Composite Anode– Silicon-carbon material– Potential to double existing capacity

• Lithium-Air (Oxygen) Technology– Metallic lithium plating model– Lithium plating modeling, experimentation and validation– O2 cathode catalyst synthesis and characterization– High throughput materials investigations– Air electrode design and analysis– Large format cell design evaluation

• Solid State Battery Technology– Solid state electrode conduction and ionic conductivity

experimentation and analysis– Predictive model development and validation

Lithium Dendrite Formation

Cycle 1

Cycle 8 Cycle 13

Cycle 4

(M. Karulkar - Ford)

Lithium Plating Model

(M. Karulkar - Ford)

Solid State Electrode Conductivity

(A. Sastry – U of M)