Why electric vehicles are catching fire?
In recent times, there have been multiple instances of electrical vehicles catching fire in public areas. These incidents are mainly associated with electric two-wheelers (e2W). Such incidents are a major cause of concern for the EV industry and its customers. This triggered the conversation about the safety of life and property, it also cast a shadow on India’s strive towards adopting eMobility.
Is it because of hot weather conditions?
Blaming hot weather conditions is wrong. The product is always designed and developed in accordance with the geographies it is being sold. The environmental conditions are a major input requirement for product development. It is true that summers are getting hotter with each year and climate change is evident. But it is not as high as to cause thermal runaway incidents in battery which is causing fires. It requires a temperature of a few hundred degrees Celsius to cause thermal runaway and it is impossible to reach such a high temperature just with ambient temperatures rising. The EVs have a thermal derating feature inbuilt as a safety measure, which switches off the battery from around 45°C to 50°C. Yes, the higher temperatures affect the life and efficiency of the vehicle but do not cause fire incidents.
Are short circuits the root cause?
Most of the recent incidents of fire can be attributed to short circuits causing an uncontrolled current flow. Though the investigation by OEMs is ongoing. It could be due to poor cell design and a lack of a sound battery management system (BMS). A BMS is an electronic system that is connected to the battery pack and constantly measures its various performance parameters like voltage, current, and temperature. This data helps BMS to calculate battery charging and discharging rate, battery life, and efficiency.
The batteries in EVs are connected in series with electronics in place. Hence, a short circuit and fire can easily kick-start a chain reaction causing a fire incident. This is called a thermal runaway incident. According to most industry experts, this is the cause of fire and vehicles bursting into flames.
Measures taken
The OEMs have initiated internal investigations into these incidents. The Ministry of Road Transport and Highways (MoRTH) has also ordered a probe into these incidents and has reached the Centre for Fire Explosive and Environment Safety (CFEES) to carry out investigations. As per the government guidelines, the OEMs are recalling an entire batch of vehicles if one from that batch was involved in a fire incident.
What can be done?
The failsafe measures shall be implemented into the design. Proper sensor technology should be implemented to measure real-time temperatures and communicate the same with BMS to take decisions. The BMS shall switch off the vehicle if the battery temperature reaches above a defined temperature. It shall communicate the problem with the customer and ask him/her to take the vehicle to the authorized dealer or a designated spot. This can save both life and property.
Measures on the charger side shall also be taken, they should be equipped with intelligent sensor technologies to measure the battery temperatures while charging. It shall also detect the overcharging conditions and electrically detach to avoid dendrite growth, leading to short circuit events. The data from the charger should be taken to check the performance of the battery that can be cross-referenced with BMS data.
Conclusion
It is imperative that we build and adopt EV standards as per Indian conditions. Most of the current industry standards are not as per India. The conditions in India are not as it is there in the west, hence the same process cannot be copy-pasted here. We also need to build multiple third-party labs for battery certifications at different elevated temperatures. This can avoid fire incidents and bring in more customer confidence. More and more customers will refrain from buying EVs if OEMs and industries do not take safety measures. Bigger companies can take sales hits but start-ups will not be able to do so.
