The Ministry of Heavy Industries (MHI) has amended the testing parameters for enhancing the human safety of electric vehicles (EVs), incentivized under the production-linked incentive (PLI) program for automobiles and auto components and the Faster Adoption and Manufacturing of Electric and Hybrid Vehicles (FAME) II program.

The new safety measures will be made mandatory from October 1, 2023, for claiming incentives under the PLI and FAME II programs.

Requirements for Electric Power Train Vehicles 

The rechargeable electric energy storage system (REESS) with 100% state of charge (SOC) will be tested for ingress protection IP X7 as per IEC 60529. There should be no fire or explosion during the IP X7 testing of REESS. Alternatively, immersion into water test can be performed per ISO 6469-1:2019 for medium (M) and heavy (N) category vehicles.

Battery Management System for REESS

The battery management system should be a microprocessor or microcontroller-based circuit.

It should comply with the electromagnetic compatibility requirements per AIS 004 Part 3 or AIS 004 Part 3 Rev 1 as applicable.

The battery management system should be verified for the following safety features during REESS testing:

• Over-charge protection
• Over-discharge protection
• Over-temperature protection
• Overcurrent protection
• Short circuit protection

Thermal Propagation Test

A thermal propagation test has been introduced to assess the REESS’ capacity to endure thermal propagation, which may occur due to an internal short circuit causing a single-cell thermal runaway, and this process should not lead to the ignition or explosion of the REESS.

The manufacturer of the REESS is required to provide a risk reduction analysis using recognized industry-standard methods. This analysis should outline the potential hazards to vehicle users and bystanders stemming from thermal propagation triggered by an internal short circuit resulting in a single-cell thermal runaway. It should also detail how the identified risk mitigation measures or features contribute to reducing these risks.

The manufacturer of the REESS is required to provide a comprehensive system diagram encompassing all pertinent physical systems and components. These relevant systems and components play a role in safeguarding vehicle users and bystanders against potential risks arising from thermal propagation triggered by a single-cell thermal runaway.

Acceptance Criteria

During the thermal propagation test of REESS, there should be no evidence of fire and explosion triggered by a single-cell thermal runaway.

The REESS should have an audio-visual warning for early detection of thermal events or gases in case of thermal runaway of cells. This warning should be activated at least five minutes before thermal propagation, such as fire and explosion.

Test Procedures

The thermal propagation test should encompass the entire REESS or the relevant REESS subsystems, which include the cells and their electrical connections. If manufacturers opt to conduct the test on the related subsystem, they must demonstrate that the test outcomes reasonably reflect the safety performance of the complete REESS under identical conditions. If the electronic management unit for the REESS is not physically integrated within the cell enclosure, it must remain functional during the test.

Test Conditions

The test should take place under controlled conditions, specifically at a temperature of 25 ± 2°C. At the start of the test, the SOC should be set to a minimum of 95%.

The test can be carried out using a modified testing apparatus designed to minimize the impact of any modifications made. The manufacturer must furnish a list detailing the modifications applied. Additionally, the test should be conducted within an indoor testing facility or shelter to eliminate the potential influence of wind.

Initiation Method

The test necessitates the utilization of a block heater, film heater, or an alternative heating device to initiate thermal runaway. If employing a block heater of the same size as the component cell, one of the component cells must be substituted with the heater. In the case of a block heater smaller than a component cell, it can be positioned within the module in direct contact with the surface of the initiation cell. If opting for a film heater, it must be affixed to the surface of the initiation cell.

The heating process should adhere to the following conditions:

• A plate or rod heater should be employed, encompassed by ceramics, metal, or insulating material. The heating area of the heater that makes contact with the cell should, whenever possible, not exceed the surface area of the cell.
• Upon installation, the heater should be gradually heated to its maximum power. The initiation process should be terminated when thermal runaway is detected or when the measured temperature exceeds 300°C. The cessation of initiation through heating should be achieved within a 30-minute timeframe.
• The heater’s heating area should be in direct contact with the cell surface, and the heater should efficiently transmit its heat to the initiation cell.
• The selection of the initiation cell should consider accessibility through the chosen triggering method and prioritize cells where heat generated by thermal runaway can most readily propagate to adjacent cells.

Measurement of Voltage and Temperature

When measuring voltage, it is essential to ensure that the original electrical circuit remains unaltered. The temperature sensor’s accuracy should fall within the range of ± 2°C, with a sampling interval of less than one second.

The battery cells used in constructing the REESS must display a visible manufacturing date, including the month and year of production. The REESS manufacturer should also imprint the manufacturing date on the battery pack.

The cells employed in the REESS assembly should hold certification per IS 16893-Part 2 and Part 3, issued by either a NABL-accredited laboratory or a testing agency authorized under CMV Rule 126.

To monitor cell temperatures, the battery pack within the REESS should be equipped with a minimum of four temperature sensors. These sensors must be strategically positioned to provide accurate temperature readings. If the temperature exceeds 60°C, an audio-visual alarm should activate as a warning. If the vehicle is in operation, the battery management system should gradually cut off the power supply to the motor.

The REESS should incorporate active paralleling circuits to facilitate the parallel connection of strings, thereby eliminating the occurrence of circulating currents. These power semiconductor devices, employed for interconnecting strings, also serve as protective safety switches capable of identifying and isolating faulty strings.

Maintaining an adequate spacing distance between individual cells is also crucial to ensure efficient heat dissipation and isolate cells in the event of thermal runaway within the REESS. The intercell gap should be determined based on the specific cell geometry (cylindrical, prismatic, or pouch) in use and the cell capacity.

Each manufactured REESS must be accompanied by a traceability document that contains comprehensive information about the cells, battery management system, charger specifications, serial/batch numbers, charge-discharge data values, and other relevant details.

Technical Requirements for Electric Power Train Vehicles

The cells used in the assembly of the REESS should undergo at least one cycle of charge and discharge, conducted at a rate of C/3 current. The data from this cycling process must be diligently recorded and maintained by the REESS pack manufacturer.

The REESS must be equipped with a pressure release vent to prevent the accumulation of internal pressure and the release of gases in the event of an internal single-cell short circuit.

For REESS units with a SOC of 100%, it is mandatory to undergo testing for water ingress protection, following the IP X7 standard as defined in IEC 60529. Alternatively, an immersion test in accordance with ISO 6469-1:2019 can be conducted.

Onboard Portable Charger

The charger should have a charge voltage cut-off to avoid overcharging of REESS.

The charger should have a soft start function every time REESS is connected for charging, and it should have a pre-charge function to detect the deep discharge condition of the battery.

It should have input supply variation (230 VAC +/- 10%) protection, output voltage, and current regulation.

For every REESS produced, there must be a traceability document containing comprehensive information about the cells, battery management system, charger specifications, serial or batch numbers, charge-discharge data values, and more.

In addition, the battery management system should record crucial parameters of the battery pack, and the most recent data should be retained for at least one month. Alternatively, this up-to-date data can be stored on a remote cloud server for at least one month.

After a series of EV fires last year, Minister of Road Transport and Highways Nitin Gadkari had warned that any EV company found to be negligent in its manufacturing process would face heavy penalties and a recall of all defective vehicles ordered.

Last month, a parliamentary committee recommended that the government should extend Phase II of the FAME program for at least three years beyond March 31, 2024, to make EVs a norm in the Indian automobile market. The standing committee on Industry made this recommendation in a report relating to the MHI and presented it to Parliament.