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What separates a reliable EV from a potential fire hazard?

Experts discuss the pitfalls of poorly manufactured batteries and what sort of conditions lead to an e-scooter becoming a fire hazard.

March 30, 2022 / 08:50 AM IST
Representative image.

Representative image.

In terms of sturdiness, an electric vehicle (EV) has fewer moving parts than gasoline vehicles,” said Bhavish Agarwal in an interview with Moneycontrol, a day before the highly anticipated launch of the Ola S1 e-scooters. The statement was in response to a question regarding the robustness of e-scooters which would have to go toe-to-toe with a massive brigade of internal combustion workhorses that plied the hinterland, taking consistent abuse from the terrain and climatic conditions in their stride. Agarwal’s sentiment was later echoed by Ola Electric’s Chief Marketing Officer Varun Dubey on the day of the Ola S1 Pro’s press ride, when he told me that it has been subjected to a battery of tests that would make it suitable for India’s particularly challenging environment.

On March 26, a video began circulating on the internet, documenting an Ola S1 Pro in Pune, emitting smoke before being engulfed in flames. The video indicated that the scooter was unaccompanied by its owner, didn’t appear to have suffered any damage to its exterior shell and wasn’t next to any heat source or combustible item at the time of the incident. The company quickly issued a statement acknowledging that it was, indeed, its scooter and that it was looking into the matter. What caused the fire remains unknown to both the brand and the many viewers of the video. In a more tragic turn of events, an Okinawa scooter exploded in Vellore, killing a man and his daughter. Okinawa Motors has issued a statement blaming consumer negligence in charging the vehicle, while Ola Electric is looking into what factors, internal or external, caused the fire. While this isn’t the first time a lithium-ion battery has exploded, it has thrown the inherent fire risk posed by battery packs into sharp relief.

So under what circumstances can EV batteries catch fire? What sort of countermeasures and safety mechanisms are EV brands required to keep, and just what deviation from these standards can lead to a scooter or a vehicle posing a fire risk? “Lithium-ion batteries do not like high temperatures, especially at high state of charge,” says Chetan Maini, arguably the country’s foremost authority on battery technology. The chairman of SUN Mobility gave the world its first compact, low-cost EV – the Reva (G-Wiz in international markets) two decades ago, before going on to co-found SUN Mobility, providing li-ion battery packs and battery swapping solutions for EVs.

“At SUN Mobility, our team has been working with li-ion technology for over 17 years and understands the key challenges in safely deploying li-ion battery solutions. It starts with a stringent selection of the cell, chemistry and manufacturer and a host of tests such as over-charge, short circuit, high temperatures, nail penetration, crush, vibration testing etc. The next is a robust design of the battery pack to ensure mechanical integrity and thermal management,” says Maini, whose company has tested over 15 million kilometres with over a million swaps, till date.

Such a stringent battery of tests appear to be the standardised norm when it comes to EV manufacturing. Just how many brands conscientiously perform these checks is a matter of speculation. For a brand like Ather Energy, whose e-scooters have developed a reputation for top-notch quality and reliability, comprehensive testing is non-negotiable. “The Indian climate and road conditions are harsh and contribute to faster degradation of batteries if not addressed properly,” said an Ather Energy spokesperson, adding “At Ather, we perform 4 types of validation, namely Functional, Durability, Reliability and Safety at component and vehicle level”. An Ather Team member on the brand’s online forum threw more light on the process. “The battery is actually shielded on the chassis on both sides (…) moreover, it has gone through nail penetration testing as a part of the homologation test”. However, the team member also pointed out that battery-focussed two-wheeler crash testing standards in India do not yet exist, hence no formal crash testing is conducted. The online thread is from 2019, and Ather has not had any reported fire-related incidents concerning its scooters prior to that date or since. And while a crash testing standard hasn’t been put in place yet, the brand’s spokesperson pointed out that “India has adopted some of the most stringent tests for batteries such as AIS 156” and that Ather, as a brand, has gone a step further to adopt more stringent internal standards for thermal runaway than what AIS 156 mandates today. A thermal runaway is the process via which a leaked battery cell’s heat can be transferred to another battery cell causing a chain reaction.

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Also Read: Ola incident: Why do lithium-ion batteries catch fire 

When it comes to causes that increase the risk of fire, all experts agree on one thing: optimal temperature is crucial and that India’s climate is particularly challenging. According to Maini, “Indian climate conditions pose additional challenges. In addition to safety-related issues, at temperatures over 45 degrees celsius, the life of a li-ion battery can be less than 50 percent of a battery at room temperatures. However, there are other factors at play as well. Maini adds, “Thermal issues can be caused by defective cells, in addition to poor thermal management systems, assembly issues and poor charging”.

And at the heart of it all is an efficient battery management system. According to Ather, the key to battery pack and EV design is a battery management system hardware modified for Indian conditions. But even more crucial is to design the batteries themselves, keeping Indian conditions in mind. Ola Electric remained unavailable for comment, when asked about whether the BMS hardware for the Ola S1 Pro was made in-house or was a modified version of the one made by Etergo, the Dutch e-scooter brand acquired by Ola Electric in 2020. Hero Electric, the current market leader in the e2W space, also declined to comment when asked about just what sort of in-built countermeasures can prevent battery fire.

Ravin Mirchandani, Chairman of Ador India, also emphasises the efficacy of a BMS being integral to battery health. “Lithium-ion batteries catch fire primarily when they are improperly manufactured or damaged or when the software that operates the battery malfunctions.” Mirchandani also makes a pitch for a framework of strict government regulations that can independently inspect battery units to ensure that brands adhere to quality measures. Ador, is, among other things, a leading solution provider of high frequency and high voltage rectifier transformer sets and equipment for power stations.

But what exactly are these battery software safeguards? More importantly, what should customers looking for a safe e-scooter enquire about before making a purchase? According to Vikrant Singh, Co-founder and Chief Technology Officer at BatX Energies (a li-ion battery manufacturer), “Customers should ask for an intelligent battery management system that has up to three layers of security – ambient temperature adaptability, voltage and current control along with thermal management control, fire protection and cybersecurity. A strong BMS has multiple sensors, modules and fuses designed to prevent short circuits, ground faults and thermal runaway."

Battery flammability might also be another reason a standardised swapping system is preferable to in-built batteries. Especially in the absence of a standardised e2w crash test framework. It takes on even greater significance in light of Okinawa attributing the recent explosion of its scooter to the owner charging it via an old plug point. According to Maini, “At SUN Mobility when our batteries come into the station, we cool them down through advanced thermal management in the station and the battery.”

“The station has advanced algorithms that perform multiple checks on each battery before it is dispensed to the customer,” he adds, pointing at the need for a fairly comprehensive battery monitoring ecosystem, which goes beyond the efficacy of a battery management system alone. “With battery swapping solutions, two concerns are addressed – charging is not happening in the vehicle and while charging, the temperature is reduced due to the advanced thermal management system which prevents rapid degradation of li-ion batteries.”

With the government ordering an independent inquiry into the recent e-scooter fire-related incidents, it’s clear that a standardised form of battery safety test needs to be put in place for the public trust in EVs to be fully restored. While brands with clean records do make for a safer choice, fire-related incidents have a way of looming over the entire sector like a dark cloud. Ather Energy, whose flagship product, the 450X was in development for 18 months before being launched, insists that like them, other e2W makers too should invest time and effort in extensive on-road testing of a product instead of being in a rush to commence commercial production.

In the meantime, the standardisation of safer technologies like solid-state batteries is awaited, although it could still take well over five years for those to be easily available and incorporated into a battery swapping system, a system which is more conducive to adapting to new technology as long as the battery size doesn’t change. “The use of liquid electrolytes, which are volatile and flammable when operating at high temperatures, is the primary weakness of lithium-ion batteries. Any severe external force, such as a collision can cause chemical leakage,” says Mirchandani, himself a leading expert on battery technology. Although in all fairness, ICE vehicles are far from flame-proof themselves and carry the same, if not greater risk of flammability from external collisions or other extraneous forces.

Shoddy manufacturing, even in ICE vehicles haven’t taken long to become immediately apparent. A few fire-related incidents, apart from market positioning missteps, contributed to the death of the once-promising Tata Nano. Whenever any product sees high levels of competition, the winner is usually the customer. However, in the race to dominate the rapidly growing e2W space, with staggered production and rushed developmental cycles, the one who pays the ultimate price is, alas, also the customer.



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Parth Charan is a Mumbai-based writer who’s written extensively on cars for over seven years.
first published: Mar 30, 2022 08:50 am
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