Centre To Implement Stringent Testing, Checking Norms For Battery Management System In EVs To Prevent Fires

To prevent fires in electric vehicles, the Road Transport Ministry has put in place stringent testing and checking norms for cells, battery packs and the battery management system (BMS).

The Ministry has proposed that all EVs manufactured from 1st October must comply with additional safety requirements related to battery cells and thermal propagation due to internal cell short circuits.

The Ministry had set up a panel of experts to suggest the changes.

The changes have been made in the two Automotive Indian Standards (AIS) for the EVs in the backdrop of several fire incidents in electric two-wheelers in different parts of the country.

The new norms mandate the manufacturers to provide “safety fuse” in the system so that the battery gets immediately disconnected when there is excessive heat generation or high current flow.

The provision for four mandatory sensors has been made for quick detection of anything going wrong in a vehicle's entire battery system, which gets automatically reflected in the vehicle's console, thereby alerting the driver to act.

The new norms will be applicable for two-wheelers, cars and goods vehicles.

The AIS norms specify that there must be sufficient cell-to-cell spacing distance for effective heat transfer from the cell and to isolate the cells in case of thermal runaway in the Rechargeable Energy Storage System (RESS).

In the case of two-wheelers, the BMS system must have over-voltage, over-charge, over-discharge, over-temperature, over-current and short circuit protection.

The charger will need to have a charge voltage cut-off to avoid overcharging of REESS. The charger will also have a time-based charge cut-off function which shuts off further charging based on timeout.

The revised AIS norms say that the REESS shall have an audio-visual warning for early detection of thermal events or gases in case of thermal runaway of cells. This warning shall be activated.

Thermal runaway is a chain reaction within a battery cell that can be very difficult to stop once it has started. It occurs when the temperature inside a battery reaches the point that causes a chemical reaction to occur inside the battery.

The Ministry has also issued a draft notification for mandating Conformity of Production (COP) for traction batteries used in EVs.

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