The electric vehicle industry in India is growing at a rapid pace, more so the electric two-wheeler segment. However, in the last few days, everyone’s attention has shifted toward the safety and quality of batteries used in these electric two-wheelers, thanks to four incidents of e-scooters catching fire within a week. So, why are electric scooters catching fire and how we can prevent them? That’s what we have explained in this article with inputs from EV battery assemblers.
For the uninitiated, a brand new Ola S1 Pro electric scooter recently caught fire in Pune and the video of this scary incident went viral on the internet. Around the same time, a father and daughter died in Tamil Nadu after their new Okinawa scooter caught fire when left to charge overnight. Another Okinawa e-scooter caught fire in Tiruchirappalli (TN) and a Pure EV electric scooter recently went up in flames on the side of a busy road in Chennai.
Tips to prevent Electric Two-wheelers from catching fire:
- Accelerate your electric two-wheeler gently on hot summer days
- Park your electric vehicle in shade (never under direct sunlight)
- Handle battery pack while swapping with utmost care
- Preferably ride an EV in Normal mode on hot days
- Try to charge your EV at night in summer but avoid unmonitored overnight charging
- Plug the EV for charging after its batteries cool down to room temperature
- Use of unauthorised charger not recommended
- Charging near a heat source is to be avoided
Also, it is worth mentioning that this is not the first time an e-scooter has gone up in flames in India. Similar incidents were reported in October 2021 as well when three electric scooters, including an Okinawa and a Pure EV model, caught fire within ten days. However, with at least four such incidents reported in the past seven days, the Indian government has ordered a probe for the same. Here’s what the companies have to say about the key reasons for such incidents.
The incident of an EV battery pack catching fire in an uncontrolled fashion is called a Thermal Runaway. Mayur Misra, Director & CEO of Corrit Electric, mentions that whenever energy is drawn or supplied to the cell, some amount of heat is generated in it. If we have one single cell where a controlled amount of energy is being transferred then chances of thermal runaway are minimized. However, in an average battery pack, there are over a hundred cells and combined heat generated by those can easily trigger a thermal runaway.
If a large quantity of current is transferred possibly due to a short circuit, ineffective protective measures or hardware malfunction, etc., it can result in a catastrophic situation. He adds that despite several precautions, sometimes thermal runaways do occur due to minor manufacturing flaws. In order to prevent thermal runaways, significant analysis during the design of the product has to be carried out to understand how stressed the battery pack will be during usage or during charging. Environmental factors also play a huge role in it.
Mehul Shah, VP of Transportation Business Unit at Exide Leclanche Energy Private Limited adds, The Automotive EV Industry uses high power density Lithium-ion cells to meet energy needs. Popular cells are made of NMC (Lithium Nickel ManganeseCobalt Oxide) or LFP (Lithium Iron Phosphate) which are used on the positive electrode, graphite as a negative electrode, and polymer-based film as a separator between the two.
While charging and discharging, cells are subjected to Joule heating because of the resistance of ions in electrolytes and electrodes and will vary depending on the drive cycle and the Indian ambient conditions. In absence of effective thermal management, the battery packs can get warm and through thermal runaway at approx. 120°C to 140°C (Rapid cathode decomposition and electrolyte oxidation in presence of air), they can even catch fire.
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