India extends the deadline for implementing new EV battery standards testing norms
For the electric vehicle (EV) batteries India’s Ministry of Road Transport and Highways has extended the deadline for implementation of mandatory standards and testing norms.
The testing norms were supposed to come into effect from the 1st of October 2022, However, The Ministry through modifications to certain rules like the Automobile Industry Standards (AIS) Rule 156 and the AIS Rule 039 have now stipulated battery standards and testing norms to come into effect in 2 phases. The first phase is from the 1st of December 2022 and the other components are from the 31st of March 2023, in the second phase.
In order to ensure that original equipment manufacturers (OEMs) of EV makers are well equipped to meet standards under the AIS 156 and AIS 039, the ministry stated that implementing new standards and testing norms for EV batteries has been extended.
The Norms that will be applicable from the 1st December 2022 are the following:
- The battery management system (BMS) shall be a microprocessor/microcontroller-based circuit.
- BMS shall be verified for the following safety features: a) Over-charge protection, b) Over-discharge protection, c) Over-temperature protection, d) Overcurrent protection, and e) Short circuit protection
- The charger shall have: a) charge voltage cut-off to avoid overcharging, b) soft-start function every time the 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 a minimum 1 cycle of charge-discharge at C/3 current rate. Data of this cycling shall be maintained by the battery pack manufacturer.
- Sufficient cell-to-cell spacing distance shall be maintained for effective heat transfer from the cell and also isolate the cells in case of thermal runaway in the battery. The inter-cell gap shall be decided based on the type of cell geometry used viz., cylindrical, prismatic, or pouch, and the capacity of the cells.
- Battery shall have an 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 the cells, BMS, and the charger used along with serial/batch number, charge-discharge data values, etc. shall be maintained with the manufacturer.
- Adequate protection of the cells in case of regenerative braking shall be considered in the design.
The Norms that will be applicable from the 31st March 2023 are the following:
- BMS shall comply with EMC (Electromagnetic Compatibility) requirements as per AIS 004 Part 3 or AIS 004 Part 3 Rev 1 as applicable at the EMC (Electromagnetic Compatibility) level.
- This procedure is added to evaluate the ability of the 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 the battery.
- The manufacturing date of battery cells shall be clearly visible on the cells used to build the battery pack with a clear month and year of manufacture. If the manufacturing date is in the form of code on the cells, then the manufacturer shall print the manufacturing date on the pack and shall maintain a record of the manufacturing date(s) of cells used in the assembly of the pack.
- Cells used shall be certified as per IS 16893 Part 2 and Part 3
- Battery must have a pressure release vent provided, to avoid building up of internal pressure and release of gases in case of an internal single cell short circuit.
- Battery should also 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 the 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 on critical parameters of the battery pack shall be logged by BMS and the latest data for at least one month shall be maintained. Alternatively, the latest data can be stored on the cloud (remote server) at least for one month.
The Director General of the Society for Manufacture of Electric Vehicle stated that “they are requesting all the EV battery manufacturers to immediately draw up 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”
