RECENT ADVANCES IN ENHANCED FLOODED BATTERY FOR SMART 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 tropical climate, EIL has developed Generation-2 EFB technology which passed drive cycles of SBA, NEDC and EUCAR satisfactorily. Our EFB is superior in terms of active material formulation, special grid alloy, electrolyte additives which resulted in significant increase in SBA cycle life, DCA and PSoC cyclic operation. Suppression of PCL effects due to Grid interface passivation, Negative lug thinning and Softening of PAM/NAM have been achieved. Here, we throw light on the development and evolution of EFB battery technology for major automotive players , , VW and others in India.

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

By 2021, Estimated

emission norms -113 g CO2/km - INDIA In Indian Scenario, Densely populated cities like Mumbai, Delhi, Bangalore, Chennai have very high pollution levels due to passenger cars, Heavy vehicles etc. 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 Fig: Comparison of global CO2 regulations for passenger cars, in terms of NEDC CO2/km. [1] OPPORTUNITIES IN INDIA

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

VEHICLE MINIMUM MAXIMUM Indian government has declared Tax SEGMENT INCENTIVE INCENTIVE benefits with 50 % reduction in SCOOTER 1800 22000 Excise duty MOTOR CYCLE 3500 29000 AUTO RICKSHAW 3300 41000 CARS 11000 138000 LCV 17000 187000 BUS 3000000 6600000 Prices are in Indian rupees RELATIVE IMPORTANCE OF BATTERY CHARACTERISTICS IN DIFFERENT MARKET CONDITION

BATTERY RELEVANCE WITH REGARD TO OPERATING CONDITIONS Indian Climatic condition, Road condition and CHARACTERIS TICS EUROPE / NORTH AMERICAN INDIAN MARKET driving pattern are different from the western MARKET countries as shown in table SERVICE IMPORTANCE SERVICE CONDITION IMPORTANCE CONDITION AGM VS EFB ENGINE CRANKING CAPABILITY Even though AGM gives more cycle life than EFB (CCA) HOT CLIMATE, in mild/micro hybrid application, in Indian RESERVE COLD CLIMATE, context EFB has more relevance CAPACITY PARASITIC LOAD, PARASITIC LOAD, HIGH TEMP LOW SPEED, ENDURANCE •In Indian tropical climatic conditions, under HIGH SPEED, bonnet temperature will be high. EFB CHARGE FREQUENT START- ACCEPTANCE LONG RUN, performance is less effected by the extreme STOP, temperatures compared to AGM [2] J.Valencio RECOVERY SMOOTH ROAD FROM DEEP BUMPY ROADS et al [2] DISCHARGE VIBRATION •EFB is also very economical as compared to RESISTANCE the AGM technology

- NOT CRITICAL - CRITICAL - VERY CRITICAL INTRODUCTION

EXIDE CONSERVO DIN70-ISS BATTERY IN SUZUKI CIAZ: INDIA’s FIRST DIESEL SMART HYBRID VEHICLE HYBRID TECHNOLOGY USED IN SUZUKI CIAZ : SHVS (Smart hybrid vehicle by suzuki) FUNCTIONALITIES OF SHVS 12V SYSTEM: • CRANKING • IDEAL START-STOP • POWER ASSIST DIN70-ISS: Gen 2 - ISS Battery • REGENERATIVE BRAKING ISS BATTERIES (Gen-2) UNDER SUPPLY

Battery Customer\Vehicle Model DOI DIN 70 ISS

•MSIL CIAZ Hybrid Sept’15 • MSIL ERTIGA Hybrid

DIN 55 ISS MSIL-Baleno Dec’15 (Export- Europe)

N55 ISS MSIL-Baleno (Export- Japan) Dec’15

• AUTOMOTIVE SBU - TALOJA OPPORTUNITIES IN INDIA

CONSIDERING THE SUCCESS STORY OF MSIL, ALL MAJOR CAR MANUFACTURERS OF INDIA HAVE ANNOUNCED HYBRID VEHICLE LAUNCH PROGRAMME ISS BATTERIES (Gen-2) UNDER SUPPLY

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

N55 : Gen 2 - ISS Battery

FUNCTIONALITIES SUPPORTED BY N55 BATTERY : • IDEAL START-STOP • POWER ASSIST • REGENERATIVE BRAKING ON GOING PROJECTS

NEW PRODUCT DEVELOPMENT - OEM Sl. No. Project Battery Type Present Status

1 ISS DIN60

2 TOYOTA ISS DIN 75

3 NISSAN ISS DIN 70 •Technical specifications of battery and test standards 4 FIAT ISS DIN 70 are received • Samples have been submitted to few OEM for their 5 HONDA ISS 12V 60AH preliminary test and validation 6 TML ISS 115D31L

7 M&M ISS 85D26R

8 M&M ISS 115D31R

9 CATERPILLAR ISS DIN 90 EFFECTS OF PSoC APPLICATION ON THE BATTERY

Fig: The impact of HRPSoC on Battery capacity [3] Fig: SEM images of NAM, a) healthy state b) sulfation State [3]

Under PSoC condition, Battery is subjected to various critical conditions. With increase in cycles it may lead to the different types of failure as shown in the figure as discussed in Jun furukawa et al [5]

Fig: Failure modes of the lead acid batteries Why ISS Vehicles Require Advanced Battery?

Why different? Parameter Modifications (Hybrid Vehicle Feature)

To attain full state of charge (SOC) during short  Negative plate recipe Charge acceptance  period between stops  Advanced corrosion resistant Ca Alloy (Break Energy Regeneration)  Advanced Paste Technology

To achieve frequent and fast restarting of vehicle  Negative plate recipe CCA  at lower SOC.  Advanced corrosion resistant Ca Alloy (Idle Engine Start/Stop)  Advanced Paste Technology

To retain maintenance free characteristic .  Optimization of Carbon content and adequate  (Idle Engine Start/Stop, Break Energy Water Consumption ratio with other expanders Regeneration)

Many-fold use of battery in Hybrid vehicle than in High endurance- Conventional vehicle  Advanced corrosion resistant Ca Alloy  Higher Cycle Life (Idle Engine Start/Stop, Break Energy  Special additive in Electrolyte Regeneration, Power Assist) 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 Expanded Negative grid results in thinner plates Less internal resistance PLATE Additives ‘B’ | Carbon Black- Surface Area > 800sq.m/gm Carbon enhances the charge acceptance [6-7] Max. Particle size <125 μm Controls the growth and porosity of PbSo crystals[8] ‘C’ | BaSO4 - particle size < 0.8 ± 0.1 μm 4 ‘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 LIFE CYCLE

SBA S 0101 : 2006 SBA S 0101:2014

TEST CONDITIONTest Standard : 25 : SBA ± 2 S º0101 C ( :ROOM 2006 TEMPERATURE) NEW SBA CYCLE 2014: AIR WIND VELOCITY < 2 m/s Charge

100ASTEP -1 : DISCHARGING @ 59 SEC14.0V 45 A 18.3 x I20

STEP-2: DISCHARGING @ CONSTANT 14 V , 1 SEC 1 CYCLE 300 A 60sec300 A 45A STEP-3: CHARGING @ CONSTANT 14 V , 60 SEC 300A 1sec 100 A 59sec 100 A Discharge

STEP- 4 : AFTER 3600 CYCLES – REST FOR 40-48 HRS Battery is discharged to lower SOC in new SBA

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

LIFE CYCLE IS STOPPED ONCE TEST BATTERY REACHES 7.2 V EUCAR POWER ASSIST PROFILE

EUCAR POWER ASSIST PROFILE : 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 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 NEDC LIFE CYCLE

150 NEDC DAY MODE NEDC 100 CURRENT (A) •Test Temperature = 25 ºC

CHARGE 50 Initial condition : 100%SOC 0 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 -50 •NEDC(Day + Night mode) -100 should be run up to six days (i.e.,432 cycles) -150

DISCHARGE •Rest period for a day, then -200 TIME (S) the NEDC is repeated again NEDC NIGHT MODE 125 CURRENT (A) End condition: 75 •Voltage reaches (V) ≤ 8.0 V Or

25 Internal resistance(Ω)≥ 10 Ω CHARGE -25 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 OEM requirement for mild -75 hybrid vehicle ≥ 4000 cycles -125 -175 DISCHARGE -225 TIME (S) 1. CHARGE ACCEPTANCE

CURRENT V/S. TIME FOR 1 MIN OF CHARGING N55 ISS Sample A CA TEST AT 90% SOC , 25 °C, IMAX CHARGE = 100A 120.00 Sample B 100.00 Sample E 80.00 Sample F 60.00 40.00

CurrentAmps in 20.00 0.00 1 5 10 15 20 25 30 35 40 45 50 55 60 Time in sec CURRENT V/S. TIME FOR 1 MIN OF CHARGING DIN70 ISS Sample A CA TEST AT 90% SOC ,25 °C, IMAX CHARGE = 100A 120.00 Sample B Sample E 100.00 Sample F 80.00 60.00 40.00

currentAmps in 20.00 0.00 1 5 10 15 20 25 30 35 40 45 50 55 60 Time in sec 2. SBA LIFE TEST

N55 ISS SBA LIFE TEST N55 ISS VOLTAGE AFTER 1 SEC DISCHARGE @ 300A 12.00 10.00 8.00 6.00 4.00 SBA life cycles achieved:

1 sec voltage sec 1 2.00 0.00 • N55 ISS- 36000 Cycles

• DIN70 ISS – 64800 cycles

7200

10800 14400 18000 21600 25200 28800 32400 36000 No. of cycles

DIN70 ISS SBA LIFE TEST DIN 70 ISS VOLTAGE AFTER 1 SEC DISCHARGE @ 300A 12 10 8 6 4 1 sec 1 voltage 2

0

3600 7200

18000 10800 14400 21600 25200 28800 32400 36000 39600 43200 46800 50400 54000 57600 61200 64800 No. of cycles 3. WATER LOSS TEST

DIN70 ISS

0.77 0.74 0.80

TEST CONDITIONS:

@40 °C,14.4 V, 28 DAYS /Ah)

gms REQUIREMENT:

weight loss ≤ 1 gm/Ah Water loss( Water Loss of weight (gm/Ah)

1 2 3 Sample 4. EUCAR - Life Expectancy based on Discharge Energy

Cycles achieved : • 46000 cycles CUT OPEN ANALYSIS AFTER EUCAR

POSITIVE COULD BE ROLLED SPIDER DIAGRAM FIELD RESULTS

FAILURE MODE ANALYSIS Failure mode of DIN70 ISS batteries tested on fleet vehicles

Sr. Kilometers Major Failure modes Observation: completed Positive Grid corrosion is major 1. 45000 •PAM softening cause of battery failure 2. 40000 •Positive Grid corrosion 3. 90000 •Positive Grid corrosion •Sedimentation 4. 46680 •Positive Grid corrosion •Sedimentation 5. 57000 Positive Grid corrosion FUTURE CHALLENGES

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 cycles U(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

•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. Cycle A Step-3 : Charge for 18 hrs @ Charge for 40 min @ 7×I20 , 14.4 V 2×I20 , 16V, 27 °C Discharge for 30 min @ Step-4: perform the capacity 7×I20 test C20 Step- 1 to 4 is counted as 1 unit MEETING LEVEL M1 as per EN 50432-2006 SWITCH OFF CRITERION AT EACH END OF STEP IS V ≤ 10 V 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