When I saw a Nissan Leaf cut in half at the Christchurch Innovation Expo, my first thought was: That’s one way to keep the batteries cool on an older EV.

In fact, it wasn’t extreme
EV ventilation but an EV City initiative to help emergency services train for electric vehicle fires.

EV fires are happening, from an electric vehicle that caught fire in the garage of a Pakuranga Heights home last month to the spectacular Tesla blaze on Auckland’s Harbour Bridge in March.

But in fact, statistics indicate EVs are actually much less likely to be involved in a fire than a car powered by a petrol or diesel internal combustion engine (ICE).

Ed Harvey, CEO of Christchurch-based electric charger maker ChargeNet, points to a recent study by a US insurance company that found:

And when EV fires happen, they’re almost never the result of a crash. “It’s not zero, but the possibility of your EV’s battery catching fire as the result of a collision is remote, comparable to the risk in an internal combustion-powered car,” a Wall Street Journal analysis said. (An example of it not quite being zero occurred in Nelson in October last year, when Fenz was called to a fire after a Nissan Leaf’s battery array was punctured by a fence post).

“There are very few incidents, but you read about every one of them,” Harvey says. (It should be pointed out that ICE vehicle fires have got a bit of press just over the past few months, too, including this June blaze on Auckland’s Southern Motorway, this one on the Northern Motorway, this September fire that blocked the Waterview Tunnel and this fire on a North Shore street).

For additional context, Fenz says that last year, emergency services attended a total of 1875 vehicle fires. Fenz doesn’t keep a breakdown of ICE versus EV fires although “work is being undertaken to change this,” a spokeswoman says.

But even if all 36 lithium-on fires for the year were vehicle-related (they aren’t some involve e-scooters, e-bikes or other lithium-powered devices), it would still be 1.9 per cent of fires at a time when EVs accounted for just under 3 per cent of NZ’s fleet.

And despite the rise and rise of EVs (or perhaps we should say partly because of it, in keeping with Harvey’s mythbusting take), the total number of vehicle fires has actually declined from 2103 in the year to June 30, 2019 to 2078, 2011, 1980 then 1875 over the subsequent annual reporting periods.

EV makers are also getting better and better at thermal management, Harvey says, with the primary aim of better managing the impact of fast charging on battery life than fires per se. There have been glitches along the way, including Jaguar’s recall of its I-Pace EV in June this year over a thermal overload issue – albeit one that has not caused any incidents in NZ or globally.

But despite the lower risk, when they do happen an EV fire can take more than 10 times as much water to put out compared with a fire in a petrol or diesel car, Fire and Emergency NZ says. A petrol or diesel car can take 2000 to 4000 litres to extinguish, and an EV 25,000 to 50,000 litres.

With an EV fire, there’s the first issue of “thermal runaway” – when a single cell in a battery overheats and a chemical chain reaction causes a sudden, immense amount of heat that ignites other cells. The batteries can also reignite after several days. (One of the main reasons for the cut-in-half EV is to show fighter fighters where to manually disconnect the car’s high voltage system – see the clip above).

And Fenz has been on a push to educate people that the rising popularity of lithium-ion battery-powered light vehicles, from EVs to e-scooters and e-bikes, plus various other gadgets, has heightened the risk of fires, usually tied to overheating. Fenz gave the Herald the following stats.

They are listed as “potential” lithium-ion fires because “we do not currently collect data in a way that allows us to easily identify the exact type of battery causing the fire”.

Neither has Fenz released a breakdown of the vehicles or gadgets responsible for each fire. There can even be a mix-and-match.

Fenz recently said that since 2019, there have been 15 recycling truck fires suspected to have been caused by discarded lithium-ion batteries.

New Zealand encourages lithium-ion battery recycling but doesn’t make it compulsory, like across the Tasman (one of the reasons that New Zealand e-waste pioneer Mint Innovation opened its first plant in Sydney, with no immediate plans to build one at home).

Fenz tips for safe lithium-ion battery safety

I have to say when I recently acquired an e-scooter, my default would have been to plug it in and charge it overnight. Luckily, the chap who handed it over pointed me to the documentation that explained that was a no-no, given overcharging can cause overheating. Instead, I set an alarm for four hours after plugging it in.

Fenz advice hits a range of related themes:

If the device or battery starts to smoke or emit flames

If a small battery or device such as a phone or tablet starts overheating

Source / Fenz

Chris Keall is an Auckland-based member of the Herald’s business team. He joined the Herald in 2018 and is the technology editor and a senior business writer.