Lead–acid Batteriesfor Hybrid Electric

Automobiles

What is a hybrid electric vehicle?

What does it do?

What does the battery have to do?

What are the candidate batteries?

How should we choose between them?

Battery (size proportional to capacity)

Generator / motor

Electrical energy flow (flow rate proportional to thickness)

Mechanical energy flow (flow rate proportional to thickness)

ISG

Series hybrid

Electric driveBattery (size proportional to capacity)

Generator / motor

Electrical energy flow (flow rate proportional to thickness)

Mechanical energy flow (flow rate proportional to thickness)

SLI only

Parallel hybrid

Battery (size proportional to capacity)

Generator / motor

Electrical energy flow (flow rate proportional to thickness)

Mechanical energy flow (flow rate proportional to thickness)

ISG

Series hybrid

Electric driveBattery (size proportional to capacity)

Generator / motor

Electrical energy flow (flow rate proportional to thickness)

Mechanical energy flow (flow rate proportional to thickness)

SLI only

Parallel hybrid

Types of Hybrid ElectricAutomobile

Micro- Mild- Medium Full

EV Drive

Motor assist

Regen. braking

Engine stop

Battery voltage 12 36 144 >200

Battery capacity (Ah)

50 - 60 15 - 20 6 - 8 6

State-of-charge of battery

100

50

Stat

e-of

-Cha

rge

/ %

Time

50 + 3%

50 - 3%

-100

-80

-60

-40

-20

0

20

40

60

80

100

0 500 1000 1500 2000

Time (secs)

Current A

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

Typical range of state-of-charge, rates of discharge and recharge and failure modes

Duty SLI Deep cycle High rate PSoC

Examples 12 V EV HEV , UPS, PV

Range of SoCMax. norm.disch. rateMax. norm.charge rate

Life-limitingmechanisms

85 - 90 %

10 C

0.5 C

20 - 100 % 50 - 70, 70 - 90 %

4 C

0.5 C

15 C

8 C

Corrosion,shedding

PCL 1,PCL 2 ?

Cost

Weight

Life

What factors should be consideredwhen selecting a battery for an HEV?

Grid

HSO4–HSO4

–

Lead sulfate

Negative active-material

Grid

Grid

Lead sulfate

Negative active-material

2 e–

H2H2

2 e–

H2H2

Characteristics of high-rate partial-state-of-charge operation

1. High rate - up to 15 C discharge and 8 C charge

2. Long periods without approaching top-of-ch.

3. Very large number of (small) cycles - 300,000rather than < 1,000.

–– 1.61.6

–– 1.41.4

–– 1.21.2

–– 1.01.0

–– 0.80.8

–– 0.60.6

00 10001000 20002000 30003000 40004000 50005000

Number of HEV cyclesNumber of HEV cycles

Pot

entia

l P

oten

tial v

s vs H

g | H

gH

g | H

g 22S

OSO

44

CB1 (0.2 wt.%)

CB1 (2.0 wt.%)GR2 (2.0 wt.%)

CB2 (2.0 wt.%) CB3 (2.0 wt.%)

CB4 (2.0 wt.%)

CB5 (0.4 wt.%)

CF1 (2.0 wt.%)

EoC and EoD potentials of negative plates in HRPSoC operation

Medium Hybrids

Characteristic Units Min. Power-assist Max. Power-assist

10 s Disch. power kW 25 40

10 s charge power kW 20 35

Available energy kWh 0.3 0.5

Weight kg 40 60

Cycle life cycles 300,000 300,000

Derived parameters

Specific disch. power W kg-1 625 667

Specific ch. power W kg-1 500 583

Specific energy Wh kg-1 7.5 8.3

Key FreedomCAR Performance Goals

Battery type,manufacturer

Design elements Specific power(W kg-1)

‘RHOLAB’ (8Ah)Enersys

Twin-tab to boostPower, spiral

600

Bipolar (8Ah)Effpower

Bipolar plate Pb-Impreg ceramic

1000

Ultra (8.5Ah)Furukawa/CSIRO

Additional carbonCapacitive element

500 - 600

VRLA Batteries designed for power-assist operation

The First Test Vehicle

Project Effpower

ALABC Identifier:Effpower

Battery type: Bipolar, 8 Ah, 144V

Vehicle: Honda Insight

Voltage: 144V

BATTERY MANAGEMENT• Honda Insight Battery

Management System supplied and installed by PROVECTOR

• Add-ons including CAN interface, OBD2 module and GPS module

• Effpower cell monitoring system

Project ‘Ultra’ALABC Identifier: DP 1.1

Battery type: Furukawa/CSIRO flat, 7 Ah, 12V

Vehicle: ALABC Honda Insight

Voltage: 144V

PbO2 Pb

+ – Separator

Lead–acid cell+ –

Ultrabattery

Pb

Carbon electrode

i

ii1

i2

+ –

Carbonelectrode

PbO2

Asymmetric supercapacitor

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.

Configuration of the Ultrabattery

Hybrid pulse power characterisation

(maximum power assist, battery-size factor = 35)

y = 2E-06x3 - 0.0207x2 + 59.285x + 875.37R2 = 0.9997y = 4E-07x3 - 0.0069x2 + 4.6404x + 61819

R2 = 0.9998

0

10000

20000

30000

40000

50000

60000

70000

80000

0 300 600 900 1200 1500 1800 2100 2400 2700 3000

1-h discharge energy / Wh x BSF

10-s

dis

char

ge p

ower

/ W

x B

SF

0

10000

20000

30000

40000

50000

60000

70000

10-s

cha

rge

pow

er /

W x

BSF

Available energy = 1550 Wh

Available energy goal = 500 Wh

Discharge power = 40 kW Charge power = 35 kW

High-speed and hill-climbing driving profile

0.11 Ah

-3.63 Ah

45% DoD(8 Ah battery)

Cycling procedure:discharge the cell/battery to 80% SoC and then subject to the above profile repetitively until the minimum voltage reaches 0 V.

Performance:at least four times longer in cycle-life than the state-of-the art VRLA cells

Dis

char

geC

harg

e

UC1 UC2 UC3

Ultracells

UB

Ultrabattery

200

400

600

800

0

Cyc

le n

umbe

r

C1 C2

Control cells

1000

1200

CB

Control battery

Cycling PerformanceCycling Performance(Under EUCAR Power Assist Profile)(Under EUCAR Power Assist Profile)

Power-assist HEVs on Road Test with VRLA batteries

Battery for a Power-assist HEV (~1kWh)

NiMH Li-Ion VRLA Freed’carMin.Goals

Weight (kg)(excl. BMS)

23.26 12.5 33.3 40 (inc.BMS)

Cost, $ (rawmaterials)

349Ni - lme

74Li - USGS

58Pb - lme

500 wholebattery

Life - cycles 300,000 ? 200,000+ 300,000

Life - miles 100,000+ ? 50,000++ 100,000

If hybrid electric vehicles are to contribute meaningfullyIf hybrid electric vehicles are to contribute meaningfullyto reductions in pollution, in greenhouse gas emissionsto reductions in pollution, in greenhouse gas emissionsand to relieving the pressure on world oil supplies theyand to relieving the pressure on world oil supplies theymust be adopted in very large numbers.must be adopted in very large numbers. In order for thisIn order for thisto happen such vehicles must be affordableto happen such vehicles must be affordable……