India’s Ministry of Road Transport and Highways has extended implementation deadline for mandatory standards and testing norms for electric vehicle (EV) batteries.
The mandatory EV battery standards and testing norms were scheduled to come effect from October 01,2022. The Ministry through amendments to Automobile Industry Standards (AIS) Rule 156 and AIS Rule 039 has now stipulated the in case of certain components of battery standard and testing norms will come into effect from December 01, 2022 in the first phase and other components from March 31, 2023 in the second phase.
The ministry in a statement said that implementing new standards and testing norms for EV batteries have been extended to ensure that original equipment manufacturers’ (OEMs) of EV makers are better equipped to meets standards under AIS 156 and AIS 039.
Norms that are to come into effect from December 01, 2022 are:
- Battery management system (BMS) shall be microprocessor/microcontroller-based circuit.
- BMS shall be verified for following safety features: a) Over-charge protection, b) Over-discharge protection, c) Over-temperature protection, d) Overcurrent protection, and e) Short circuit protection
- Charger shall have a) charge voltage cut-off to avoid over charging, b) soft-start function every time battery is connected for charging, c) pre-charge function to detect deep discharge condition, d) input supply variation (230 VAC +/- 10%) protection, and e) earth leakage detection as per Class 1 of Indian Standards (IS) 12640.
- Cells used to make batteries shall undergo minimum 1 cycle of charge discharge at C/3 current rate. Data of this cycling shall be maintained battery pack manufacturer.
- Sufficient cell-to-cell spacing distance shall be maintained for effective heat transfer from the cell and also to isolate the cells in case of thermal run away in battery. The inter cell gap shall be decided based on the type of cell geometry used viz., cylindrical, prismatic or pouch and capacity of cells.
- It shall have additional safety fuse or circuit breaker in addition to the features available in BMS.
- Each battery manufactured shall have a traceability document in which the details of cells, BMS, charger used along with serial/batch number, charge discharge data values etc shall be maintained with the manufacturer.
- Adequate protection of cells in case of regenerative braking shall be considered in design.
Norms that are to come into effect from March 31,2023 are:
- BMS shall comply EMC requirements as per AIS 004 Part 3 or AIS 004 Part 3 Rev 1 as applicable at ESA level.
- This procedure is added to evaluate the ability of battery to withstand thermal propagation which is triggered by an internal short circuit leading to a single cell thermal runaway and subsequent thermal propagation and shall not result in fire and explosion of battery.
- The manufacturing date of battery cells shall be clearly visible on the cells used to build the battery pack with clear month and year of manufacture. If manufacturing date is in the form of code on the cells, then manufacturer shall print manufacturing date on the pack and shall maintain record of manufacturing date(s) of cells used in the assembly of pack.
- Cells used shall be certified as per IS 16893 Part 2 and Part 3
- Shall have pressure release vent provided, to avoid building up of internal pressure and release of gases in case internal single cell short circuit.
- Shall have active paralleling circuits for the parallel connection of strings to eliminate circulating currents. These power semiconductor devices used for interconnecting strings will also act as protection/safety switches which will detect any faulty strings and isolate them. They will allow bidirectional flow of currents to charge and discharge the pack. The parallel strings will get isolated if it is detected to be faulty. Therefore, active paralleling circuits shall be mandatory.
- Data of critical parameters of battery pack shall be logged by BMS and latest data for at least one month shall be maintained. Alternatively, latest data also can be stored on cloud (remote server) at least for one month.
Sohinder Gill, director general, Society for Manufacture of Electric Vehicle, in a statement said, “we are requesting all the EV battery manufacturers to immediately draw a plan to implement the new standards as per the policy guidelines so as to ensure that they gear up their capabilities and capacities to ensure sufficient quantities of safer batteries to meet the exponential demand of EVs,”.
Amendments to EV battery testing standards: AIS-156 and AIS-038 (Rev 2):
Amendment 3 to AIS-156 (09/2022) Specific Requirements for L Category Electric Power Train Vehicles: