GS Yuasa's 5th Generation

Flooded Lead-Acid Battery Technology

for Stop and Start Vehicles

Satoshi Inagaki, Masaaki Kyo, Susumu Obuchi,

Hidetoshi Wada, Taisuke Takeuchi, Tomohiro Imamura

GS Yuasa International Ltd.

7th Advanced Automotive Battery Conference Europe 2017

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

EFB:Enhanced Flooded lead-acid Battery

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

Objective Technologies

Generation

1st 2nd 3rd 4th 5th

2009~ 2010~ 2011~ 2012~ 2017~

Charge/discharge

performance

Increased number

of plates

DurabilityHigh density

PAM

Charge acceptance

Special additive in

electrolyte

Optimized additives

in NAM with

carbon technology

: Improvement as compared with conventional batteries.

: Additional improvement as compared with .

: The new technology for the 5th generation

History of EFB technology

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

300

320

340

360

380

400

420

440

460

480

500

1990 1995 2000 2005 2010 2015 2020

Ave

rag

e m

on

thly

mil

ea

ge

/

km

Year

Market trend in Japan

Reference)

Japan automobile manufacturers association,

Passenger Car Market Trends in Japan (1995-2015)

Influence on batteries

-Few charging opportunity

-Prolonged non-operational time

under PSoC

Popularization

of Stop and Start

vehicles

Users’ average mileage has been

decreasing, because the main purpose

of car users has been changing from

leisure to daily or even weekly small

business.

Transition of user’s average mileage

Failure modes in the field (1)

Battery ： M-42 (4th generation, C20=40Ah)

Cars: 2 of different Japanese car manufacturers’ (shown as A and B)

History: A [2218km/9.8months(226km/month)] , B[2017km/9.3months(217km/month)]

5 Fatal degradation

4

3

2

1

0 No degradation

Short-circuits

Sediment ofdropped active material

Shrinkage of NAM

Sulfation of NAM

Change ofseparator color

Dendrite formation

Softening of PAM

Grid corrosion

Car A

Car B5

4

3

2

1

0

Failure modes in the field (2)

Battery ： LN3 (4th generation, C20=70Ah)

Cars: 1 of European car manufacturer’s (shown as C)

History: 30640km/22.2months(1378km/month)

Sulfatuion of NAM should be common also in European market.

Average mileage

in Germany (2013)

:1188km/month

In the literature,

sulfation of NAM under short

mileage in Europe is also shown.S. Schaeck et al., Journal of Power

Sources 196(2011) 2933

Short-circuits

Sediment ofdropped active material

Shrinkage of NAM

Sulfation of NAM

Change ofseparator color

Dendrite formation

Softening of PAM

Grid corrosion

Car C

5

4

3

2

1

0

Description of sulfation

In the Japanese car (short average mileage) In the European car (relatively long average mileage)

SEM images of sulfated NAM

Sulfation : Accumulation of highly crystallized lead sulfates (hard to recharge)

→ Bad fuel efficiency and life performance due to the poor charge acceptance.

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

Theoretical interpretation of sulfation

“Reactable Distance” in charging process

Initial stage

Electrolyte

PbSO4

Pb

Pb2+Pb2+

Final stage

Isolated PbSO4

References)

Y. Arai et al., GS Yuasa Technical Report, 11(1),24(2014)

Y. Arai et al., GS Yuasa Technical Report, 12(2),18(2015)

Y. Arai, 9th International Conference On Lead-Acid Batteries(LABAT’ 2014)

Reactable

Distance

Electrolyte

PbSO4

Pb

Isolated PbSO4 should crystallize and go into sulfation during non-operational time.

To reduce the isolated PbSO4 by enhancing the “Reactable Distance” is important.

New carbon technology for 5th generation

Features of the new carbon

CarbonParticle

Size

Electron

Conductivity

Conventional Small Fair

New Large Good

PbSO4

Conventional carbon particles

(much smaller than PbSO4)

Strategy for improving sulfation

With new carbon, the “Reactable Distance” should be enhanced by its large particle

size and high electron conductivity so that only small isolated PbSO4 will remain.

Pb

PbSO4

Electrolyte

Conventional carbon

Short

Reactable

Distance

Large isolated PbSO4

Pb

Electrolyte

Small isolated PbSO4

New carbon

Long

Reactable

Distance

Conductive endCarbons Carbons

PbSO4

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

Sulfation-accelerated battery test

Battery ： M-42 (5th and 4th generation, C20=40Ah)

Test Profile : GS Yuasa original (simulating a short mileage use)

Temperature : 10℃

28A

50s

250A 0.5s

12.85V

80s

Max. 50A

1 cycle

Charge

Discharge

Curr

ent

/ A

14.0V

90s 13.2V

40s

0.1A

2 h

(rest time)

Repeat 2 times

Repeat 10 times

Charge/Discharge

balance in the test:

Almost 100%

Sulfation-accelerated battery test

Results

Sulfation was highly suppressed in the 5th generation battery.

5th

4th8.0

8.5

9.0

9.5

10.0

10.5

11.0

0 200 400 600 800 1000

Voltage a

t th

e e

nd o

f 250A

dis

charg

e / V

Cycles

5th generation

4th generation

x1.4

Field operational test

Battery ：M-42 (5th and 4th generation, C20=40Ah)

Cars : 1 of Japanese car manufacturer’s (manufacturer A in the previous page)

History: Same 2200km/10months(220km/month) for each battery

Results

Generation

Before field

driving test

After field

driving test

AC-IR

/ mΩ

OCV

/ V

AC-IR

/ mΩ

OCV

/ V

5 th 5.3 12.73 6.2 12.40

4 th 5.3 12.72 7.2 12.29

The same effect was confirmed in the real field

Water Consumption in over charged test

Battery ： M-42 (5th and 4th generation, C20=40Ah)

Test Profile : SAE J240 modified (25A for 1min. 14.8V/25A for 10min.at 75℃)

No bad influence with 5th generation technology

Additional information

Our 4th generation satisfies the W3 level

defined in EN 50342-6.

Temp. Voltage Duration Weight loss

60˚C 14.4V 42days5.6g/Ah

(<8)

Battery ：LN3 (4th generation, C20=70Ah)0

500

1000

1500

2000

0 1200 2400 3600 4800 6000

Wate

r consum

ption

/ g

Cycles

5th generation

4th generation

Outline

1 History of our EFB technology for Stop and Start

2 Market trend in Japan and failure modes in Stop and Start

3 Concept of 5th generation technology

4 Results of accelerated test and field operational test

5 Conclusion

Conclusion

GS Yuasa’s 5th generation battery with new carbon technology highly suppressed

the sulfation of NAM in accelerated battery test and field operational test.

Other findings

Sulfation of NAM was the major failure mode in Japanese Stop and Start real

market in which the users’ average mileage has been decreasing.

The new technology has no bad influence on the water consumption.

GS Yuasa’s 5th generation battery is suitable for short-trip users.

Thank you for your attention.