RECENT ADVANCES IN ENHANCED FLOODED BATTERY FOR SMART MILD HYBRID POWER TRAINS By Debashish Mazumdar, Ashwini Kulkarni & Achim Luelsdorf

Exide Industries Ltd (EIL) ,R & D center, INDIA

CONTENTS• ABSTRACT• INTRODUCTION• CHARACTERIZATION AND VALIDATION• RESULTS AND DISCUSSION• FUTURE CHALLENGES• REFERENCES• ACKNOWLEDGEMENT

ABSTRACT

To serve the critical demand of battery for Smart Mild Hybrid Vehicles under tropicalclimate, EIL has developed Generation-2 EFB technology which passed drive cycles ofSBA, NEDC and EUCAR satisfactorily. Our EFB is superior in terms of active materialformulation, special grid alloy, electrolyte additives which resulted in significantincrease in SBA cycle life, DCA and PSoC cyclic operation. Suppression of PCL effectsdue to Grid interface passivation, Negative lug thinning and Softening of PAM/NAMhave been achieved.Here, we throw light on the development and evolution of EFB battery technologyfor major automotive players Suzuki, Nissan, VW and others in India.

Keywords: EFB, mild/micro-hybrid, SHVS, PSoC, LAB

Fig: Comparison of global CO2 regulations for passenger cars, in terms of NEDC CO2/km. [1]

By 2021, Estimated emission norms -113 g CO2/km - INDIA

In Indian Scenario, Densely populatedcities like Mumbai, Delhi, Bangalore,Chennai have very high pollution levelsdue to passenger cars, Heavy vehiclesetc.

Huge potential exists for mild / micro

hybrids (more economical compared

to fully hybrid / electric) in developing

countries like INDIA

Market driving forces:

•Govt. initiatives

(Subsidized schemes like FAME)

•Fuel economy

•Stringent emission norms

INDIAN SCENARIO

FAME (FASTER ADOPTION AND MANUFACTURING OF ELECTRIC/HYBRID VEHICLES)

OPPORTUNITIES IN INDIA

An INDIAN govt. Initiative

Target by 2020:• 6-7 million hybrid/electric vehicle sale.• 9500 million liters of cumulative saving .• 2 Million ton reduction in pollution and green house gas emissions.

Indian government has declared Taxbenefits with 50 % reduction inExcise duty

VEHICLE SEGMENT

MINIMUM INCENTIVE

MAXIMUMINCENTIVE

SCOOTER 1800 22000

MOTOR CYCLE 3500 29000

AUTO RICKSHAW 3300 41000

CARS 11000 138000

LCV 17000 187000

BUS 3000000 6600000

Prices are in Indian rupees

BATTERY CHARACTERIS

TICS

RELEVANCE WITH REGARD TO OPERATING CONDITIONS

EUROPE / NORTH AMERICAN MARKET

INDIAN MARKET

SERVICE CONDITION

IMPORTANCE SERVICE CONDITION IMPORTANCE

ENGINE CRANKING CAPABILITY (CCA)

COLD CLIMATE,

PARASITIC LOAD,

HIGH SPEED,

LONG RUN,

SMOOTH ROAD

HOT CLIMATE,

PARASITIC LOAD,

LOW SPEED,

FREQUENT START-

STOP,

BUMPY ROADS

RESERVE CAPACITY

HIGH TEMP ENDURANCE

CHARGE ACCEPTANCE

RECOVERY FROM DEEP DISCHARGE

VIBRATION RESISTANCE

- NOT CRITICAL - CRITICAL - VERY CRITICAL

RELATIVE IMPORTANCE OF BATTERY CHARACTERISTICS IN DIFFERENT MARKET CONDITION

AGM VS EFB

Even though AGM gives more cycle life than EFB in mild/micro hybrid application, in Indian context EFB has more relevance

•In Indian tropical climatic conditions, underbonnet temperature will be high. EFBperformance is less effected by the extremetemperatures compared to AGM [2] J.Valencioet al [2]

•EFB is also very economical as compared tothe AGM technology

Indian Climatic condition, Road condition anddriving pattern are different from the westerncountries as shown in table

DIN70-ISS: Gen 2 - ISS Battery

EXIDE CONSERVO DIN70-ISS BATTERY IN SUZUKI CIAZ:

INDIA’s FIRST DIESEL SMART HYBRID VEHICLE

FUNCTIONALITIES OF SHVS 12V SYSTEM:• CRANKING• IDEAL START-STOP• POWER ASSIST• REGENERATIVE BRAKING

HYBRID TECHNOLOGY USED IN SUZUKI CIAZ :SHVS (Smart hybrid vehicle by suzuki)

INTRODUCTION

Battery Customer\Vehicle Model DOI

DIN 70 ISS

•MSIL CIAZ Hybrid • MSIL ERTIGA Hybrid

Sept’15

DIN 55 ISS

MSIL-Baleno(Export- Europe)

Dec’15

N55 ISS MSIL-Baleno

(Export- Japan) Dec’15

• AUTOMOTIVE SBU - TALOJA

ISS BATTERIES (Gen-2) UNDER SUPPLY

OPPORTUNITIES IN INDIA

CONSIDERING THE SUCCESS STORY OF MSIL, ALL MAJOR CAR MANUFACTURERS OF INDIA HAVE ANNOUNCED HYBRID VEHICLE

LAUNCH PROGRAMME

EXIDE CONSERVO N55-ISS BATTERY IN 48V RETROFIT KITS BY M/S ALTIGREEN PROPULSION LABS

N55 : Gen 2 - ISS Battery

FUNCTIONALITIES SUPPORTEDBY N55 BATTERY :• IDEAL START-STOP• POWER ASSIST• REGENERATIVE BRAKING

ISS BATTERIES (Gen-2) UNDER SUPPLY

Altigreen technologies makes mild hybrid Retrofit kits, which won many international awards like• IDTechEx Europe 2016 award for the Most Significant Innovation in Electric Vehicles.

• Altigreen had joined the list of Top 20 Automotive Tech Solutions of 2016 by CIO Review, USA.

NEW PRODUCT DEVELOPMENT - OEMSl. No. Project Battery Type Present Status

1 TOYOTA ISS DIN60

•Technical specifications of battery and test standardsare received• Samples have been submitted to few OEM for theirpreliminary test and validation

2 TOYOTA ISS DIN 75

3 NISSAN ISS DIN 70

4 FIAT ISS DIN 70

5 HONDA ISS 12V 60AH

6 TML ISS 115D31L

7 M&M ISS 85D26R

8 M&M ISS 115D31R

9 CATERPILLAR ISS DIN 90

ON GOING PROJECTS

Fig: Failure modes of the lead acid batteries

Under PSoC condition, Battery is subjected to various criticalconditions. With increase in cycles it may lead to the differenttypes of failure as shown in the figure as discussed in Junfurukawa et al [5]

Fig: The impact of HRPSoC on Battery capacity [3]

Fig: SEM images of NAM, a) healthy state b) sulfation State [3]

EFFECTS OF PSoC APPLICATION ON THE BATTERY

ParameterWhy different?

(Hybrid Vehicle Feature)Modifications

Charge acceptance

To attain full state of charge (SOC) during short period between stops

(Break Energy Regeneration)

Negative plate recipe Advanced corrosion resistant Ca Alloy Advanced Paste Technology

CCA

To achieve frequent and fast restarting of vehicle at lower SOC.

(Idle Engine Start/Stop)

Negative plate recipe Advanced corrosion resistant Ca Alloy Advanced Paste Technology

Water Consumption

To retain maintenance free characteristic .

(Idle Engine Start/Stop, Break Energy Regeneration)

Optimization of Carbon content and adequate ratio with other expanders

High endurance-Higher Cycle Life

Many-fold use of battery in Hybrid vehicle than in Conventional vehicle

(Idle Engine Start/Stop, Break Energy Regeneration, Power Assist)

Advanced corrosion resistant Ca Alloy Special additive in Electrolyte

Why ISS Vehicles Require Advanced Battery?

DESIGN PARAMETERS

PARAMETER Brief Remarks

ALLOY Base alloy C21 alloy (Ca,Ba,Sn,Al) Ca –Sn-Ag Both alloys are Highly corrosion and creep resistant [5]

POSITIVE PLATE Additives Additive ‘A’ Additive ‘E+A’

High paste Density- oxide mill particle size < 6 μm Effective utilization of active material

NEGATIVE

PLATE Expanded Negative grid results in thinner plates Less internal resistance

Additives ‘B’ | Carbon Black- Surface Area > 800sq.m/gm

Max. Particle size <125 μm

Carbon enhances the charge acceptance [6-7]

‘C’ | BaSO4 - particle size < 0.8 ± 0.1 μm Controls the growth and porosity of PbSo4 crystals[8]

‘D’| Vanilex-N Prevents the solidification of spongy lead [8]

ASSEMBLY COS Pb-Sb alloy

PAM/NAM RATIO 1.2-1.3 More amount of NAM plays a role in increasing the CA

PE ENVELOPE Special Grade

TESTS CONSIDERED FOR ISS APPLICATION

1 CHARGE ACCEPTANCE @ 90% SOC , ROOM TEMPERATURE

2 SBA LIFE CYCLE| SBA S 0101 : 2006

3 EUCAR POWER ASSIST PROFILE LIFE CYCLE

4 NEDC LIFECYCLE

5 17.5% DOD| CYCLE LIFE @ 27 °C

6 50 % DOD | CYCLE LIFE @ 40 °C

SBA S 0101 : 2006 SBA S 0101:2014

LIFE CYCLE IS STOPPED ONCE TEST BATTERY REACHES 7.2 V

STEP -5 : TOPPING UP WITH WATER ONLY AFTER 30000 cycles NOT MENTIONED MENTIONED

STEP- 4 : AFTER 3600 CYCLES – REST FOR 40-48 HRS

STEP-3: CHARGING @ CONSTANT 14 V , 60 SEC 100 A 100 A

STEP-2: DISCHARGING @ CONSTANT 14 V , 1 SEC300 A 300 A

STEP -1 : DISCHARGING @ 59 SEC45 A 18.3 x I20

TEST CONDITION : 25 ± 2 º C (ROOM TEMPERATURE)

AIR WIND VELOCITY < 2 m/s

1 CYCLE

Test Standard : SBA S 0101 : 2006

NEW SBA CYCLE 2014:

300A 1sec

14.0V

60sec

59sec

45A

100A

Charge

Discharge

Battery is discharged to lower SOC in new SBA

SBA LIFE CYCLE

EUCAR POWER ASSIST PROFILE :

FOR example,N55 ISS BATTERY | C20 = 45 AH | C2 = 25.2 AH

CYCLE LIFE TEST parameters

EUCAR MODIFIED

OPERATING TEMPERATURE 25 ºC 40 ºC

C2 (Current, A) 12.6 A 18 A

5 C2 63 A 90 A

EUCAR TEST:

STEP-1: Discharge @ C2 up to 60% SOC

STEP-2: Start EUCAR profile | run for 10K cycles (1 unit)

STEP-3: Recharge @ 16V/12.6A for 20 hour

STEP-4: Discharge at C2 rate upto 10.2 volts (note down C2 capacity)

STEP-5: Recharge at 16V/12.6A for 24 hrs

REPEAT: Again repeat from step-1 to step -5

END CONDITION : C2 capacity ≤ 50% of initial value/ Voltage drop ≤ 8.4V

EUCAR POWER ASSIST PROFILE

-200

-150

-100

-50

0

50

100

150

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200 1250

CH

AR

GE

TIME (S)

NEDC DAY MODE

DIS

CH

AR

GE

CURRENT (A)

-225

-175

-125

-75

-25

25

75

125

0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200

TIME (S)

NEDC NIGHT MODE

DIS

CH

AR

GE

CURRENT (A)

CH

AR

GE

NEDC

•Test Temperature = 25 ºC

Initial condition : 100%SOC

•NEDC(Day + Night mode)should be run up to six days(i.e.,432 cycles)

•Rest period for a day, thenthe NEDC is repeated again

End condition:•Voltage reaches (V) ≤ 8.0 VOrInternal resistance(Ω)≥ 10 Ω

OEM requirement for mildhybrid vehicle

≥ 4000 cycles

NEDC LIFE CYCLE

N55 ISS

0.00

20.00

40.00

60.00

80.00

100.00

120.00

1 5 10 15 20 25 30 35 40 45 50 55 60

Cu

rre

nt

in A

mp

s

Time in sec

CURRENT V/S. TIME FOR 1 MIN OF CHARGINGCA TEST AT 90% SOC , 25 °C, IMAX CHARGE = 100A Sample A

Sample B

Sample E

Sample F

DIN70 ISS

0.00

20.00

40.00

60.00

80.00

100.00

120.00

1 5 10 15 20 25 30 35 40 45 50 55 60

curr

en

t in

Am

ps

Time in sec

CURRENT V/S. TIME FOR 1 MIN OF CHARGINGCA TEST AT 90% SOC ,25 °C, IMAX CHARGE = 100A

Sample A

Sample B

Sample E

Sample F

1. CHARGE ACCEPTANCE

0.00

2.00

4.00

6.00

8.00

10.00

12.00

72

00

10

80

0

14

40

0

18

00

0

21

60

0

25

20

0

28

80

0

32

40

0

36

00

0

1 s

ec v

olt

age

No. of cycles

SBA LIFE TEST N55 ISSVOLTAGE AFTER 1 SEC DISCHARGE @ 300A

0

2

4

6

8

10

12

36

00

72

00

10

80

0

14

40

0

18

00

0

21

60

0

25

20

0

28

80

0

32

40

0

36

00

0

39

60

0

43

20

0

46

80

0

50

40

0

54

00

0

57

60

0

61

20

0

64

80

0

1 s

ec

volt

age

No. of cycles

SBA LIFE TEST DIN 70 ISSVOLTAGE AFTER 1 SEC DISCHARGE @ 300A

2. SBA LIFE TEST

N55 ISS

DIN70 ISS

SBA life cycles achieved:• N55 ISS- 36000 Cycles• DIN70 ISS – 64800 cycles

3. WATER LOSS TEST

0.77

1 2 3Sample

0.74 0.80W

ater

loss

(gm

s/A

h)

DIN70 ISS

TEST CONDITIONS:@40 °C,14.4 V, 28 DAYS

REQUIREMENT:weight loss ≤ 1 gm/Ah

Loss of weight (gm/Ah)

4. EUCAR - Life Expectancy based on Discharge Energy

Cycles achieved :• 46000 cycles

CUT OPEN ANALYSIS AFTER EUCAR

POSITIVE COULD BE ROLLED

SPIDER DIAGRAM

FAILURE MODE ANALYSIS

Failure mode of DIN70 ISS batteries tested on fleet vehicles

Sr. Kilometers completed

Major Failure modes

1. 45000 •PAM softening

2. 40000 •Positive Grid corrosion

3. 90000 •Positive Grid corrosion•Sedimentation

4. 46680 •Positive Grid corrosion•Sedimentation

5. 57000 Positive Grid corrosion

Observation:Positive Grid corrosion is major cause of battery failure

FIELD RESULTS

EUROPEAN MANUFACTURERS ABIDING BY EN 50432-6 STANDARD

TEST LEVEL M1 LEVEL M2 LEVEL M3

MICRO-HYBRID TEST Normalized mean Rdyn increases ≤ 1.5 after 8000 cyclesU(EOS) ≥ 9.5 Volts.

Ce ≥ 50% after 8000 cycles

17.5% DoD CYCLE TEST ≥9 units ≥15 units ≥18 units

50% DoD CYCLE TEST ≥150 cycles ≥240 cycles ≥360 cycles

FUTURE CHALLENGES

•Dynamic charge acceptance EN 50342-6, clause 7.3 Test under going, Target is to achieve IDCA ≥ 0.40

17.5 % DOD cycle test

17.5% DOD - TEST PROCEDURE

Step-1 : Discharge the battery for 2.5 Hours @ 4 x I20 , 27 °C

Step-2: Perform cycle A 85 times.

Step-3 : Charge for 18 hrs @ 2×I20 , 16V, 27 °C

Step-4: perform the capacity test C20

Step- 1 to 4 is counted as 1 unit

SWITCH OFF CRITERION AT EACH END OF STEP IS V ≤ 10 V

Cycle A

Charge for 40 min @ 7×I20 , 14.4 V

Discharge for 30 min @7×I20

MEETING LEVEL M1 as per EN 50432-2006

REFERENCES

[1] The International Council on Clean Transportation Website ( www.theicct.org )[2] J.Valencio, M.Fernandez, F.Trinidad, L.Sanz, Journal of power sources 187 (2009) 599-604. [3] Jun yang, Chen Hu, Hao wang, kai Yang, Jing Bing Liu and Hui yan, International journal of Energy Research (2016) DOI:10.1002/er 3613[4] Article name : What is Fame Indian scheme ? (www.atthenergy.com)[5] Kenji Nakano, Syuhei Takeshima and Jun Furukawa. Furukawa Review, No. 32 2007[6] Ellen Ebner, Daniel Burow, Alexander Borger, Michael Wark, paolina Atanassova, Jesus Valencio , Journal of power sources 239(2013) 483-489.[7] Patrick T. Moseley, David A.J.Rand, Ken Peters, Journal of power sources 295 (2015) 268-274.[8] Pavlov.D, Lead Acid Batteries : Science and technology, Copyright 2011 , Elsevier B.V.

ACKNOWLEDGEMENT

The Authors acknowledge the contributions made by other R&D colleagues Mr. SS Vaze, Ms. Asma Khan and Mr. Mohan Tirukoti in compiling and interpreting the test results & graphs.

Thank you