EV Fires

Subject: Science & Tech

Section: MSc

Context- The growing EV mishaps are worrying. The Centre should act fast to establish battery safety standards.

Concept-

Sales of EV two wheelers have risen ﬁve times (463 per cent) to 2.31 lakh in 202122.
This is the fastest growing segment, accounting for over half of total EV sales.

Why only EV Two wheelers catching fire:

That only two wheeler batteries are catching ﬁre, and not those of cars or three wheelers, is not surprising because of two reasons —
- one, there are more two wheelers on the roads and,
- two, unlike the other segments, the two wheeler market is highly price sensitive, which has apparently driven the manufacturers to cut costs by compromising on safety.

EV Batteries:

There is little doubt that the main culprit is battery chemistry.
Lithium Ion batteries are of many makes, depending upon which other elements lithium has been married to.
The most commonly used chemistry in two wheelers is nickel manganese cobalt, or NMC, which while being the best in terms of performance and costs, are the most inﬂammable.
Not surprisingly, most two wheeler makers have procured NMC batteries from China. These are not suited to India’s hot climate.
Other Li Ion chemistries, such as lithium ferro phosphate (LFP) and lithium titanate oxide (LTO) are costly, but safe.

What can be done:

NMC could be used with safety features.
There is plenty on the technology table — such as
- dual fuse for each cell which will automatically cut oﬀ if either the temperature or current exceeds a limit,
- active thermal management to cool down the battery,
- a temperature indicator with a buzzer to warn the rider and an emergency switchoﬀ system.
The Centre should incentivise the use of solid state batteries, which have no inﬂammable, liquid electrolytes such as those based on abundant, indigenous materials such as sodium, zinc and aluminum.