STRATEGIC STUDY OF PLACEMENT OF BATTERY PACK FOR SMALL PASSENGER ELECTRIC VEHICLES

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

STRATEGIC STUDY OF PLACEMENT OF BATTERY PACK FOR SMALL PASSENGER ELECTRIC VEHICLES

Ashutosh Yadav, Tanmay Agarwal, Vishal Chaskar Tata Technologies, Pune, India

Abstract - As the automotive industry expects rapid transition towards electrification, the packaging of most complex and safety critical component also seen as a mammoth task. Our study presents a systematic packaging strategy and location-finalization methodology for integrating a lithium-ion battery pack into a small passenger vehicle. Batteries occupy significant space in electric commercial vehicles, making battery placement a critical design decision. Deciding on battery pack location has impact on various factors like vehicle CG, Vehicle Load distribution, packaging of surrounding aggregates, safety of the battery pack and also of the occupant, Cost impact etc. to name a few. In the electric conversion of the passenger small commercial vehicle, various locations were evaluated underfloor, rooftop, under-seat, rear overhang & under cabin with respect to C.G, lateral load transfer, tractive effort, energy consumption & available traction on wheels.

Each option posed unique challenges like elevated center of gravity, increased drag & traction limited torque. In this study, detailed packaging studies, certain vehicle calculation are made and each location are evaluated with its pros and cons. Study also proposes preferred location for such vehicles. This study provides practical insights into safe, efficient, and scalable battery packaging for small passenger EV platforms.

Key Words: Small Passenger Vehicle, Battery Packaging, Vehicle C.G, Load Distribution,M2 Category.

1. INTRODUCTION

Globaldemandforcarbonnetzeroaimstobalancegreenhousegas(GHG)emissionswithremoval,targetingnet-zeroby2050 (orlaterforsomedevelopingcountriesby,2070)tolimitglobalwarmingto1.5°C.Thisdemandhasemphasizedonrapid electrificationoftransportationsystemacrossthenationslikeIndiaandChina.WhileelectrificationofLocomotiveshasgained andachievedgoodstabilitybuttheautomobileindustryisstilllackingthatgrowthconsideringkeyparameterslikeVehicle Range,Safetyofkeycriticalcomponentlikebatterypacks,andpackagingoflargerbatterypacksintothevehicle.

Therapidelectrificationofthepassengervehiclesegment particularly-carryingpassengercommercialtransportunits demands innovative engineering strategies that balance vehicle performance, passenger comfort, safety, and long-term reliability.Atthecoreofthistransformationliesacriticaldecision:whereandhowtopackagethebattery.

Ourworkisfocusedonthestrategicframeworkforbatterypackagingandlocation.Itexaminesarangeofinfluentialfactors, includingavailablespacewithinvehiclearchitecture,Centerofgravityimplications,structuralintegrity,andhigh-voltagecable routingchallenges allessentialtoensuringsafetyandcompliancewithAIS038Rev2standards.

Severalconfigurationswerestudiedandevaluatedbasedonpracticaltrade-offssuchascrashsafety,impactonpassenger ergonomics,coolingsystemcomplexity,andserviceability.

2. PACKAGING STRATEGY

2.1

Vehicle Selection and Conversion

ThevehiclechosenforbatterypackagingisM2categoryasperIndianstandardswithGVW<5tonwithpassengercapacityof morethan8seats.

Batterycapacityunderconsiderationis60-65KWh&batterypackweightrangeis180-210kg.

VehicleConfigurationisFrontAxleDriven,4X2,WithE-axleConfiguration.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

2.2 Vehicle Selection and Conversion

VehicleCo-OrdinateSystem(VCS)isdefinedasperindividualvehicleCADenvironmentrequirements. Ingeneral,belowSchemeshowsVCSPositionandVehicleDirections.

Fig 3:VehicleCo-OrdinateSystem(VCS)andVehicleLevelDirection

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

3. Evaluation of Strategic Packaging Locations of Battery

TheDMU(DigitalMockUp)studycarriedoutforvariousbatterypacksizesapplicableforsaidapplication. TheeachbatterypacklocationStudyinvolved,

 ImpactonvehicleC.G,

 VehicleWeightsDistribution

 AccessibilityandServiceability

 Packagingconstraintsduetosurroundingaggregates Evaluationstudyforvariouslocationsdescribedbelow–

Layout 1: – Battery placement – Between Chassis Structure –

The battery was placed between the front & rear axles approximately at center of vehicle wheelbase. At said locations importantparameterevaluatedareVehicleGroundClearances,VehicleRampOverangle,andNecessaryprotectionneeded againststonehitting,WaterSplashingandMudAccumulationpossibilityinadditiontotheoneslistedabove.

Thebatteryplacementwasdonesuchasgroundclearanceleastimpacted.ComparedtoitsICEvariant.Thelayout1isshownin fig4

Inthislayoutbatterywasmountedattherooftopofthevehicle.Thiswasdoneasitwaseasytomountwithminormodifications onbody.Additionally,thebatterycoversweredesignedforaestheticallyandaerodynamicconsiderationsasitwascompletely visiblefromoutside.Thelayoutisshowninfig5

Based on the technical analysis, the height of the C.G increases in this layout which impacts vehicle dynamic manoeuvre capability.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

Layout 3: – Battery placement – At BIW End (Below Last Row Seat)

Anewlocationwasselectedtomountthebatteryatrearsideofvehicle.Themodificationrequiredtoelevatethefloor.Elevated floorimpactstheheadroomforrearseatingpassenger.Thesepositionalsocallsforminimummodificationinsurrounding layout.

Technicalanalysisindicates,theC.Gwillreducecomparedtorooftopmountingbutwillaffectthegrade-ability.Packagingatthe rearsidewillhavetheriskofdamagingthebatteryduetorearendcrashfromfollowingvehicle.

Layout 4: – Battery placement – Mounted Inside cabin below Seats.

Batterywasplacedinsidethecabinunderthepassengerseats.Theadvantagehereisthatbatterywillbesafefromhittingthe road,bumpers,etc.ascomparedtootherplacementsandwillhavelowC.G.Splitbatteryproposalcanalsobeusefultoimprove thebatterycapacityandvehiclerange.

4. Vehicle C.G and Load Distribution Calculations Methodology:

Below Flow chart helps to understand and calculate the Vehicle C.G Calculation with all the aggregates in place, Load distributiononFrontAxleandRearAxleinLadenandUn-ladencondition.

Thiscalculationprocessiscarriedoutforall4layoutsdiscussedabovetostudytheimpactofBatteryPackPlacementsOn VehicleC.GandLoadDistribution.

Thecalculationsforall4layoutsweredoneasperflowchartbelow–

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

5. Packaging Study and Observation with Various Battery Location Proposal

Variouslayoutsstudiesdoneinearliersectionshavecertainbenefitsandcertainlimitations.AdditionalstudyofCGand Loaddistributionhaddeepenedtheinsightsaboutthedynamicsofthevehicleandpackagingbenefitsandlimitations aboutaparticularlayout.

Battery placement –Between Chassis Structure

Battery placement –Mounted on rooftop

Pros

 Lowerscentreofgravity(CG)

 BetterweightdistributioninvehicleFAW andRAW.

 Goodtractionatall4wheels

 Good thermal management and crash protection

 Simplifiedhigh-voltage(HV)wiring.

 Easytomount

 Easeofaccessibility

 No intrusion of BIW inside cabin for accommodatingthebatterypack.

 IncaseofFireincidents,rescuecanbeeasy

 Coolingsystempackagingwillbesimple.

 Weight distribution is better with this layout.

Cons

 Ground Clearance and Vehicle Ramp Over angle may get compromised.

 IntrusionmightbeneededinBIW for accommodating the battery pack

 Vehicle CG point shifted in Zdirection resulting in increase in Vehiclerollovertendency.

 ResultsinincreaseofvehicleDrag Force.

 Requires heavy structure at the top of the vehicle to sustain batteryload.

 HV cable routing will be lengthy resultinginhighercostimpact.

Battery placement – At BIW End (Below Last Row Seat)

 BIWlayoutisopenforbetterutilizationof seatinglayout.

 LOWfloorheightatcenterportioncanbe possible.

 IncaseofFireincidents,rescuecanbeeasy

 Harness routing for HV cable will be simplerandoptimized.

 Layout is better suitable for Rear Wheel Driveoption.

 Considerablereductioninvehicle tractive force front wheel due to shiftofC.GawayfromFrontAxle.

 Affectscrashsafety,fromRear

 To meet Departure angle requirement,rearfloorneedtobe lifted quite up in Z direction. Resulting in Reduces headroom forrearseats.

 Battery damage in case of Crash from Rear may affect its life and furtherusability

Battery placement –Mounted Inside cabin below Seats.

 Efficientspaceutilization.

 Lowerscentreofgravity(CG)

 BetterweightdistributioninvehicleFAW andRAW.

 Good thermal management and crash protection

 Simplified high-voltage (HV) and LV Routing.

 LayoutisbetterutilizedforallWheelDrive option.

 Serviceabilitywillbebitcomplex

 IncaseofFireIncident,possibility ofoccupantsafetyiscritical.

 Ground Clearance and Vehicle Ramp Over angles may get compromisedtosomeextent.

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 13 Issue: 03 | Mar 2026 www.irjet.net p-ISSN: 2395-0072

6. CONCLUSION

OutComeofthestudyistosharetheinsightsofvariouspossiblelayoutofbatterypackinsmallpassengervehicle.Theimpact ofbatterypackbeingoneofthehighestweightcontributoronvehicleC.Gandloaddistributionplaysavitalroleandcannotbe overlooked.

Eachlocationhasitsownbenefitsanddrawbacks,soitisimportanttofindabalanceofallbasedonapplicationoftheproduct. Saiddocumentwillcertainlyhelptoformthebasistoidentifyandworkoutthesuitablepositiontoendusers.

REFERENCES

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3.GiovanniBelingardi,AlessandroScattina:BatteryPackandUnderbody:IntegrationintheStructureDesignforBattery ElectricVehicles ChallengesandSolutions

4.ChristopherKrüger,SebastianSpohr,DavidMerdivan,PeterUrban:Avoidingstructuralredundanciesbetweenthevehicle bodyandthebatteryhousingbasedonafunctionalintegrationapproach

5.ThomasD.Gillespie,FundamentalsofVehicleDynamics