Kathmandu-A BYD Atto-3 electric vehicle had  caught fire on  May 7 at Pathari, Morang. The government has now launched an investigation into the matter. 

The Department of Transport Management has stated that it has initiated a study into the BYD Atto 3 fire incident following complaints from stakeholders amid the increasing use of electric vehicles.

The department has assigned the preliminary phase of the study to the Vehicle Fitness Test Center (VFTC) in Itahari.

The department has has been instructed to study the electric vehicle fire incident that occurred in Pathari, Morang on May 7, Pawan Kumar Regmi, head of the Vehicle Testing Office, Itahari, informed Biznessnews. 

'The department has sought us to conduct a preliminary study of the incident last week and submit a report,' said Regmi, head of the office. 'We have started our work accordingly. We will submit a report to the department after completing the study.'

BYD has long promoted its Blade Battery as one of the safest battery technologies and claimed that it has minimal risk of catching fire.

To reinforce that claim, Cimex Inc Pvt Ltd, the official distributor of BYD vehicles in Nepal, had even demonstrated a 'nail penetration test' a few years ago. However, the same Atto 3 using the battery that was claimed not to catch fire even under a nail penetration test, had now caught fire. 

Taking this into  account, the department has launched a study to determine the exact reasons why the electric car caught fire.

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.

The Vehicle Testing Office has stated that it is preparing a report after reviewing all the available evidence. Whether the investigation will be able to determine the condition of the burnt-out Auto 3 and establish the actual cause of the incident remains to be seen. The amount of time and effort the engineers involved will need to uncover the truth will become clear only after the study report is released.

Based on the available videos, the fire appears to have originated in the area where the battery pack was located. However, the official cause of the fire can only be established through a technical (forensic) investigation.

Since the department has directed the Vehicle Testing Office in Itahari to prepare and submit a preliminary report, if that report is unable to identify the actual cause of the fire, the department may instruct the authorized distributor and the manufacturer to commission an independent third-party forensic investigation to determine the cause.