Advanced Mobility Platform for Electric Vehicles

Standards and Regulations for EVs in India

With number of electric vehicles users increasing day by day, concerns about safety of electric vehicles are also rising.  In sub-continent countries like India, thermal & structural safety of electric vehicles (especially HV batteries) is always questioned. Add to that, there were some of unfortunate incidences which further raise doubts. To overcome these anxiety about electric vehicles and make them safer, government of India further raises bar in terms of regulations for electric vehicles. In India, government agencies such as ARAI drafts and publishes various standards known as ‘Automotive Indian Standards’ (AIS).  All vehicle manufacturers have to meet these AIS to get the Type of approval for starting the production.

In case of ICE vehicles, regulations were more focused on measuring engine out emissions. In case of Electric vehicles, regulations are focused more on,

  • Confirming thermal & structural safety of electric vehicles & HV battery
  • Calculating parameters such as Range, efficiency of EV’s
  • Confirming safety of charging system of electric vehicles AC & DC

Below are the major regulations for checking these parameters related to electric vehicles segment wise:

M & N categories of vehicle: (Passenger & commercial vehicles with four or more wheels)

Safety of HV Battery & Powertrain: (AIS 38)

This AIS have been amended in December 2022 to include many tests focusing on thermal and structural safety of HV batteries. With inclusion of these additional tests, makes these very stringent norms to pass. This AIS splits into two part i.e. Part I & Part II. Part I of AIS 38 has below tests for checking how Powertrain of electric vehicle is safe against electric shock & warning mechanisms in case of failure.

Part I of AIS 38:

  1. Protection against electrical shock:  Since voltage of electric vehicles ranges from 60 V to 800V, it’s very critical to ensure protection against electric shock to occupants as well to other persons coming in contact to vehicles.
    • Some of the tests included to check the same are as below,
    • Protection against direct contact
    • Protection against indirect contact
    • Isolation resistance
    • Protection against water effects
  2. Rechargeable Electrical Energy Storage System (REESS): This part of AIS checks about failsafe mechanism of HV battery. Test included in this AIS are about how electric vehicle gives warning in case of failure of HV batteries.
    • Accumulation of gas
    • Warning in the event of failure in REESS
    • Warning in the event of low energy content of REESS.

Part II of AIS 38:

Part 2 of AIS 38 is more stringent and focus specially on safety of Rechargeable Electrical Energy Storage System i.e. HV battery.

  • Vibration
  • Thermal shock and cycling
  • Mechanical impact : Mechanical Shock – Vehicle based or  Component based
  • Mechanical integrity
  • Fire resistance: Vehicle specific test. Component based test
  • External short circuit protection
  • Overcharge protection
  • Over-discharge protection
  • Over-temperature protection
  • Overcurrent protection
  • Low-temperature protection
  • Management of gases emitted from REESS
  • Warning in the event of operational failure of vehicle
  • Warning in the case of a thermal event within the REESS
  • Thermal propagation.

Standards common for all types of vehicles (L, M & N categories)

1. Measurement of Electrical Energy Consumption  Electric Power Train Vehicles (AIS 39):

AIS 39 gives methodology to measure electrical consumption of electrical vehicles in wh/km for all types of vehicle. This measurement in way indicates how much efficient you electric vehicle is. This is equivalent to fuel economy in terms of Lit / km for ICE vehicles.

Below is the process for estimating electrical consumption:

  1. Initial complete charging of vehicle
  2. Running vehicle with different pre-defined cycles: These running cycles are nothing but pre-defined driving profiles in terms of speed vs. time these running cycles are different for different categories of vehicles.
    • L categories (2 Wheelers): Cycle used is Indian Driving Cycle, total 34 cycles each of 108 sec duration.
    • M1, M2 (with GVW<3.5T ) & N category: Cycle used is Part 1 of Modified Indian Driving Cycle , total 22 Cycles each of 195 s
    • M2 (with GVW>3.5T) & M3 vehicles: Cycle used is Delhi Driving Cycle, total 25 Cycles.

Distance travelled during this running is measured as ’D’ in km.

Suppose will take example of M1 category of vehicle, which completes about 26 km during MIDC cycle during test. (For total 22 cycles of MIDC cycles)

D= 26 km

c) Charge the Battery: HV Battery charged again to full condition. During this charging, energy cons. meter kept between main power and vehicle socket measures Energy consumption ‘E’ in kW.

In our case, suppose energy required again to complete battery charging is 6 KW.

E=6 kW

d) Measurement of energy consumption (C, kWh/km): The electric energy consumption is defined by the formula,

C = E / D

Therefore, energy consumption can be calculated as below,

C =6/26

C = 0.23 kW/ km

Therefore we can say that, energy consumption of electric vehicle per Km is 0.23 kW. This parameter is good indicator for comparison between two electric vehicles. This parameter is equivalent Mileage in terms of km/Lit.

2. Electric Power Train Vehicles –  Method of Measuring the Range (AIS 40):

Range is most important parameter of electric vehicles, most of the users is anxious over range of EV’s. Methodology for measuring of range of EV’s is given by AIS 39. Below is the process for estimating electrical consumption.

(a) Initial charge of the Rechargeable Energy Storage System (REESS);

(b)Application test cycles:

  • L category vehicles: The driving cycle shall be the Indian Driving Cycle (IDC) as given in Annexure-II of CMVR.
  • M1, M2 (with GVW up to 3500 kg) and N category of vehicles: The driving cycle shall be Part-I of the modified Indian driving cycle as given in Annexure-IV B of CMVR.
  • M2 (with GVW above 3500 kg) and M3 category of vehicles: The driving cycle shall be Delhi Driving Cycle as given in AIS-049:2003 as amended and revised from time to time (Rev 1).

(c) Measurement of distance covered, i.e. Range km

For example suppose we have taken M1 category of vehicle and test cycle for finding out range is MIDC cycle. Vehicle is fully charged before start of test,

No of cycles completed by vehicles, before completely exhausting recharge = 132 cycles

Distance covered in one MIDC cycles =1.014 km

Therefore range of vehicles = 132*1.014= 133.8 km

3. Measurement of Net Power & Max. 30 min. power (AIS 41):

Full load characteristics of motor are very critical parameter. This is expressed in terms of graph of Motor Power & speed, which is evaluated by AIS 41. This standard also gives details about measuring net power and max 30 min power. This test can be conducted by testing individual motor on bench dynamometer or testing vehicle on chassis dynamometer as per manufacturer’s option.

4. Safety Requirements of Traction Batteries (AIS 48):

Before Dec. 2022 many of the tests mentioned in AIS 38 were part of AIS 48. Some of the critical tests related to HV battery are as below,

  1. Electrical tests :
    • Short Circuit Test  (Cell Level or Battery Module or Battery Pack)
    • Overcharge Test (Cell Level or Battery module or Battery Pack)
  2. Mechanical tests
    • Vibration Test
    • Shock Test
    • Penetration Test  (Cell Level or Battery module)

Standards for Two wheelers AIS 156  (L category of vehicle)

This standards specially defined for L Category Electric Power Train Vehicles i.e. two wheeler EV’s. This standard is amended recently last year to make stringent considering recent thermal incidents in two wheeler EV’s. This is very much similar to AIS 38 which is defined for 4 wheelers. This standard is divided into two parts; Part is more for safety of electric Powertrain while part 2 is safety of HV batteries.

  1. Part I:
  • Protection against electrical shock
    • Protection against direct contact
    • Protection against indirect contact
    • Isolation resistance
    • Protection against water effects
  • Rechargeable Electrical Energy Storage System (REESS)
    • Accumulation of gas
    • Protection against electrolyte spills
  • Functional safety
    • Additional functional safety requirements
    • Driving or riding back Wards
  • Protection against Water Effects
    • Washing
    • Flooding
    • Heavy Rainstorm

2. Part II:

  • Vibration test
  • Thermal shock and cycling
  • Mechanical Shock – Vehicle based or  Component based (manufacturer choice)
  • Fire resistance Vehicle specific test., Component based test
  • Over-discharge protection
  • Over-temperature protection

Standards for charging system(AIS 138) for all types of vehicles

AIS 138 Part I: Electric Vehicle Conductive AC Charging System

AC charging system:   This standard is for checking safety provision of AC charging system of supply voltage up to 1000V for electric vehicles of L, M & N types of vehicles. This standard includes operating conditions & characteristics of supply voltage & connection to vehicles. Below are the requirements given in AIS 138 Part I.

  • Details of Proximity function
  • Details of Mandatory Safety Functions  
  • Vehicle Identification Functions provided in EVSE-AC
  • Energy Metering Functions provided in EVSE-AC              
  • Functions related to Communication to Grid
  • Connection between the EVSE and the EV
  • Contact sequencing for AC Fast Charging
  • Specific requirements for vehicle inlet, connector, plug and socket-outlet
  • Service life of inlet/connector and plug/socket-outlet
  • Breaking capacity            
  • IP degrees         
  • Insertion and extraction force   
  • Latching of the retaining device etc.

AIS 138 Part II:  Electric Vehicle Conductive DC Charging System

This standard gives requirements about DC charging connections to electric vehicles up to 1500V.

  • Verification that the vehicle is properly connected
  • Measuring current and voltage
  • Retaining/releasing coupler
  • Locking of the coupler
  • Compatibility assessment
  • Verification of vehicle connector voltage
  • Short circuit test before charging etc.

Overall summary of component wise regulations related to electric vehicles:

No.ComponentDescriptionAIS Standard
    1HV BatterySafety of Traction Battery & Powertrain- M & N categoriesAIS 38
Safety of Traction Battery & Powertrain- M & N categoriesAIS 48
Safety of Traction Battery & Powertrain- L category (Two wheelers)AIS 156
2MotorEnergy ConsumptionAIS 39
Net Power & Max. 30 min. powerAIS 41
3AC charging UnitElectric Vehicle Conductive AC Charging SystemAIS 138 Part I
4DC Charging UnitElectric Vehicle Conductive DC Charging SystemAIS 138 Part II
  5Vehicle LevelRange CalculationAIS 40
CMVR Type Approval for Electric Power Train VehiclesAIS 49

So overall these are the major tests related to HV systems for getting type approval. These are only summarized version of regulation and standards required for electric vehicles, however there are many details requirements for any electric vehicles. Since electric vehicle development is still in early days of development, these regulations will also evolve and become more and more robust to consider real world scenarios. This will help to make electric vehicles more safe and user friendly in years to come.

Vinayak K

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