Selection of Appropriate Batteries for HEVs and PHEVs

Patrick T. Moseley

Advanced Lead–Acid Battery Consortium

Contents

1. The wind of change in automobile design 2. HEV battery performance requirements 3. Enabling VRLA in HEV duty 4. Vehicle demonstrations 5. Conclusion

CO

2

Emission Targets

Europe USA Japan 130 g CO 2 per km by 2015 (95 g/km by 2020) 160 g CO 2 per km by 2020 (presently 204 g/km) 138 g CO 2 per km by 2015

Costs and Benefits of Different Types of Hybrid Electric Automobile Full Micro EV Drive Motor assist Regen. braking Engine stop Energy savings * Supplementary cost * EECPS 8% $0-600 + AABC 2008 Medium 15-20% $3,500 + 40% N/A

Types of Hybrid Electric Automobile

Medium Full Micro EV Drive Motor assist Regen. braking Engine stop Battery voltage Battery capacity (Ah) 12 50 - 90 144 6 - 8 >200 6

12 EIA: Alternative technology vehicles will Constitute v54% of light-duty vehicle sales by 2030 10 8 6 4 2 0 2006 2007 2015 Electric/fuel Cell/ Plug-in Hybrid Hybrid Electric Vehicle Flex Fuel Diesel 2020 2030 US DOE Energy Information Administration Annual Energy Outlook 2009 Reference Case

Ragone Plot for several Battery Chemistries M. Winter Advanced Battery Technologies for Automobiles Conference, Essen 2009

Key FreedomCAR Performance Goals Characteristic 10 s Disch. power 10 s charge power Available energy Weight Cycle life Derived parameters Specific disch. power Specific ch. power Specific energy Units kW kW kWh kg cycles W kg -1 W kg -1 Wh kg -1 Max. Power-assist 40 35 0.5

60 300,000 667 583 8.3

Ragone Plot with Freedom Car Goal for Maximum Power-Assist Hybrid marked as

Far and away the most affordable battery option is lead–acid Batteries in HE autos are small (~ 1 kWh) so that there is little weight penalty 98% of lead–acid batteries are recycled Lead–acid battery manufacturing capability is in place Lead–acid presents no fire/explosion hazard

But there is one problem - Negative plate sulfation (PCL3) 0 cycles –1.6

–1.4

–1.2

–1.0

–0.8

0 1735 cycles 3191 cycles H 2 evolution 50  3 % SoC 2000 4000 HEV cycles 6000 8000

Charge and discharge currents experienced by ‘Insight’ battery during hard driving

Battery/Capacitor Combination works successfully in HEV Duty PbO 2 Pb Lead–acid cell Energy - Yes Power - No PbO 2 C Hybrid Super-capacitor Power - Yes Energy - No Combination Power and energy OK

Configuration of the UltraBattery

– + – Separator + PbO 2 PbO 2 Pb Carbon electrode Lead –acid cell Ultrabattery +

i

i 1

i

–

i 2

Pb Asymmetric supercapacitor Carbon electrode

The UltraBattery is a hybrid energy storage device, which combines an asymmetric capacitor and a lead-acid battery in one unit cell, without extra electronic control.

UltraBattery

Combined battery/asymmetric supercapacitor

Cycling Performance

(Under EUCAR Power Assist Profile)

Ultra Battery Installed in Honda Insight - fits in the volume originally occupied by NiMH

Power-assist HEV on Road Test with ’ULTRA’ VRLA battery

UltraBattery – 12 module voltages matched well at the start of the test

Module voltages during emission test after 100,000 miles – matched better than at start – without conditioning!

JSAE, Yokohama, June 2008

Battery for a Power-assist HEV (~1kWh) Life - cycles Life - miles NiMH 300,000 VRLA ULTRA Freed’car Min.Goals

370,000+ 300,000 100,000+ 100,000+ 100,000

Comparing the Costs of Lead-Acid with Nickel Metal Hydride (NiMH) & Lithium Li-Ion Battery Type Battery Cost ($) Hybrid Cost ($) Total Cost Hybrid’n ($) Time to Payback (years) 3.1

Time to Payback Battery 0.8

USABC Freedom Car AABC 2008 AABC 2008

ALABC/ CSIRO 2008

USABC Ultimate Goal NiMH German (Honda) Li-Ion Best Estimate Future Cost* (Takashita)

Ultra Battery Current

500 2000 1000

260

1500 1500 1500

1500

2000 3500 2500

1760

5.05

3.9

2.7

3.1

1.6

0.4

The Ultrabattery, demonstrated by the ALABC, has exceeded the benchmark goals established by the US Advanced Battery Consortium. Assumptions: 12,000 Miles/Year, Battery size 1KWH Fuel $4/Gal - $640/Yr, Conventional 30MPG, Hybrid 50 MPG *Current cost at least equal to NiMH

Homogeneous Carbon-supplemented Negative

– PbO 2 + – Separator Pb PbO 2 + Carbon Lead –acid cell Asymmetric supercapacitor +

i i

– PbO 2 Pb with Carbon electrode

Cell with dual-function (Faradaic and capacitive) negative plate – has the carbon blended with the active material. Even simpler than the Ultra Battery.

Cells with the carbon blended into the active material.

Changes in negative-plate potential during simulated HEV cycling - Upper curves EOCV, lower EODV.

-2.0

2

2CF1 1 0.4CB5

1

1000

2CF1 1

2000

0.4CB5

1 0.4CB5

1

4000 5000 CF1 0.4 m 2 g -1 , CB5 1400 m 2 g -1

Batteries with carbon blended in to active material Comparison of End of Discharge Volts HEV Bus - High-Rate Partial-State-of Without Plate 50 40 30 20 10 0 Charge Cycling With Plate Additive 0 50,000 100,000 150,000 200,000 250,000 Cycles

Bipolar Design

ALABC Identifier: Battery type: Vehicle: Voltage: Effpower Bipolar Honda Civic IMA 158 V

Further Progress on the Horizon The carbon/capacitor solution to battery performance is stimulating additional research that promises even more progress in lead-acid technology. For example: Most batteries through the years have used “monopolar” technology with two plates per cell and each cell connected with metallic connectors.

With bi-polar technology, cells are stacked in a “sandwich” construction to that the negative plate of one cell becomes the positive plate of the next. Fewer plates and connections are required.

The bi-polar advantage: greater power with less weight in a smaller package.

28

VRLA Batteries designed for power assist operation Battery type, manufacturer Ultra (8Ah) Furukawa/CSIRO Bipolar (7Ah) Effpower Design elements Specific power (W kg -1 ) Additional carbon Capacitive element Bipolar plate Pb Impreg ceramic.

Extra carbon mixed with NAM 500 - 600 1000

Honda Civic Test Cycle

Test uses a mix of aggressive high-speed and city course running

Civic Test

Track testing ran for 40,000 km at Millbrook.

Bench test of battery to identical protocol completed 170,000 km without failure.

Vauxhall Combo van for retro-fit plug-in hybrid

Hybrid Fuel Cell Bus will be equipped with high-carbon VRLA battery

Honda Civic HEV to be equipped with Ultra battery

Conclusions

When the present range of hybrid electric automobiles was designed the only battery capable of performing the necessary function was the nickel metal hydride type.

The ALABC, which is a world-wide group of 53 companies, has shown how lead–acid batteries can be produced to fulfill the necessary requirements, with

no loss of function

, but with

a large reduction in cost

.

Thank You