Kathmandu-Last Thursday, a BYD Atto 3 caught fire in Pathari, Morang. After dropping off the groom, the vehicle was parked under the shade of a tree for cooling. Shortly after being parked, smoke began emerging from the lower section of the car, where the high voltage battery is located.

As the Atto 3 started catching fire, wedding attendees and passersby found the incident unusual and surprising. Many recorded photos and videos and uploaded them to social media. Dozens of online media outlets also shared the footage. Videos from multiple angles have surfaced, showing everything from the initial smoke to the burnt remains of the Atto 3 being lifted by a crane onto another vehicle.

In electric vehicle fires, the high voltage battery rarely burns completely. In many previous fire incidents, the high voltage battery pack had remained intact.

However, in this BYD Atto 3, the Blade Battery, which is marketed as highly safe and capable of passing the nail penetration test, also caught fire. That makes the incident unusual.

According to the videos, the driver removed the bumper and disconnected the high voltage battery connection. Even after that, thick smoke continued pouring from the rear underside of the vehicle before flames erupted.

Shortly after the fire began, flames could be seen bursting outward. When a high voltage battery burns, the cells explode and release sparks and flames. Based on publicly available videos and explanations given by observers, the Atto 3 battery fire can be interpreted as follows:

Initial smoke:
At the beginning of the videos, thick white smoke can be seen emerging from the underside of the vehicle, where the high voltage battery pack is located. This indicates the start of a “thermal runaway” inside the battery.

Gas venting:
As the battery cells heat up excessively, internal pressure increases and gases escape through built in safety vents. During this stage, a hissing sound and rapid release of smoke are typically observed. A similar pattern appeared in the Pathari Atto 3 fire.

Sparking and small flames:
Some time after the smoke appeared, small sparks and faint flames became visible beneath the vehicle. These flames were likely caused by the extreme heat generated through chemical reactions inside the battery.

Rapid ignition:
Once heat spreads from one battery cell to another inside the pack, the fire intensifies rapidly. The videos clearly show large flames erupting from beneath the car within moments and spreading toward the tires and upper body.

Explosive sounds:
While the fire was burning, small explosion-like sounds could be heard. These sounds are likely from individual battery cells rupturing or exploding. The spreading sparks and flames also support this observation.

Full combustion:
In the final stage, the fire engulfs the entire vehicle. Lithium ion batteries, including Blade Batteries, are extremely difficult to extinguish because they can generate their own oxygen and do not easily go out with water alone. Within minutes of the fire starting, a fire engine from Pathari Municipality arrived at the scene. However, despite continuous spraying of water, the fire could not be controlled.

Remains:
After the fire subsided, the vehicle’s main body and the battery compartment appeared completely destroyed. Even after the visible flames were gone, videos showed smoke still coming from the battery while the burnt vehicle was being lifted by a crane. The vehicle was briefly placed back on the ground until the smoke stopped before it was finally loaded for transport.

The videos suggest that the fire originated from the battery pack area. This raises the possibility of an internal short circuit or external damage affecting the battery. However, the official cause will only become clear after a technical forensic investigation.

Seven days after the incident, Cimex Inc Pvt Ltd, the authorized distributor of BYD vehicles in Nepal, has still not issued any public statement.

Since the high voltage battery itself burned completely, BYD is also expected to take interest in the matter. Given the complexity of the incident, it remains uncertain whether Cimex Inc or BYD will publicly disclose the actual reason behind the battery fire even after completing their investigation.