Four Electric Vehicles(EVs) emitted smoke and eventually went up in flames over the last four days in India, thus raising alarm over the safety of these e-scooters. While one incident was reported from Maharashtra, the other three were from Tamil Nadu. Happening at a time when the summer is just beginning to set in across the subcontinent and at a time when people are actively considering switching to Electric vehicles, these events have sparked widespread concerns. To understand the issues that might have led to the recent fires and to know about possible solutions, WION spoke to Aravind Kumar Chandiran, Assistant Professor, Dept of Chemical Engineering, IIT-Madras.
According to him, such issues of batteries emitting smoke and eventually catching fire are not a sudden phenomenon. These are actually the result of a build-up(in the battery) that happens over a considerable period of time. The key to tackling such issues lay in the Battery Management System algorithms. Mobile phones and Electric vehicles have a 'Battery Management System'(BMS), which is meant to manage a rechargeable battery, ensure it operates safely and efficiently. BMS is designed to monitor the parameters(temperature, charging, discharging) associated with the battery pack and its individual cells, apply the collected data to eliminate safety risks and optimize the battery performance.
Read | EV tax benefits in India: Everything you need to know before buying an electric vehicle in 2022
"Electric vehicles operate in climatic conditions that prevail across India, which includes very cold to hot and humid weather and the battery is required to function across these places. Likewise, there are many users who ride the EV for a few hours every day and for long hauls, whereas others use it casually, for short rides. There are also differences in charging patterns that the users follow. The algorithms in the BMS must be extensively tested for these dynamically varying conditions, to facilitate the best and safe performance of the batteries" he elaborated. Given that EVs are in the initial stages of adoption in India, Aravind Kumar is of the opinion that it is the complete responsibility of the Original Equipment Manufacturers and EV companies to deliver well-tested vehicles, that are suited for Indian conditions and users. However, he also feels that batteries emitting smoke and catching fire/exploding are part of an evolutionary process that was witnessed even in mobile phone batteries, and was eventually perfected.
Speaking about the major factors behind damage caused to electric vehicle batteries, he said that it could be thermal abuse(high or low-temperature variations), mechanical abuse(accident or crash) and also electric abuse(overcharging and deep discharging cycles). He added that their lab at IIT Madras was also conducting controlled explosions in batteries by inducing the above abuses, to better understand what specific factors lead to the smoke and fire. "By identifying these symptoms or any minute details and changes that we observe in the batteries under abuse, we will be able to detect the issues beforehand and develop sensors or alerts to inform the rider. Once a battery starts emitting smoke, there is only about 30-60seconds for escape and that time is very crucial for the rider" he added.
In terms of developing such mechanisms to detect battery failure, he said that mobiles have finally evolved to a stage where they can warn of overheating when completely charged when the battery is losing efficiency etc. Likewise, he believes that further research and studies into EV batteries can evolve a triple-redundant mechanism to avoid such mishaps. "As more data is available on the EV batteries and their functioning, we can have the BMS and sensors to alert the rider in case of battery danger. With targeted measures, we could even save the battery from further damage and even prevent damage to the vehicle" he adds.
When comparing EV scooters and cars/trucks, scooters are more prone to such battery issues, as scooters lack the liquid cooling technology, which is found in larger vehicles. Despite the higher standards, even the major global automobile and electric vehicle brands have suffered cases of explosion in their models of Electric cars. It is notable that while mobile phone batteries store approximately 10 watt-hours of energy, electric vehicles store a few Kilowatt-hour to tens of Kilowatt-hours of energy, which is exponentially higher and thus making the complications of heating, thermal management, etc very high. As a researcher in the field, Aravind feels that such setbacks and mishaps are part of the evolution of the technology, and it would eventually lead to better solutions and safety systems being built into EVs.
