Electric carmakers say fire no concern

Tesla Model S

Jil McIntosh

SPECIAL TO THE STAR

You'll see a lot of hybrid technology at the Canadian International AutoShow. What you'll quickly learn is there's a lot of power inside hybrid and electric vehicles, including high-voltage cables and big storage batteries. That may cause you to worry about what might happen if you crashed one.

Their manufacturers, however, say you shouldn't be any more concerned than you would be with any other type of vehicle. Firefighters and Transport Canada agrees.

"There's a misconception that because hybrids have high-voltage systems there's a risk of shock or electrocution," says John-Paul Farag, of Toyota Canada's advanced technology and powertrain division. Although the company has been selling hybrids for 10 years, Farag says there have been no safety issues, mostly thanks to advanced vehicle engineering.

Only gasoline-electric hybrids are currently available in Canada, but plug-in hybrids, extended-range vehicles and all-electric cars are on their way. All of them must be okayed by Transport Canada.

A government spokesperson says hybrids are required to meet the same safety standards as all other vehicles, which include crash tests, seatbelts, bumper heights and other qualifications; there are no extra electric-specific standards.

Farag says hybrids are safe because the electricity is isolated. All high-voltage cables are sheathed in metal and colour-coded bright orange.

"There are also electronic safeguards in the vehicle that will automatically shut down the power in a collision," he says. "These relays disconnect the flow of energy from the battery, so if that were to happen and emergency responders arrive on the scene, they would know there is no risk of these high-voltage cables being live or electrified. If they have the Jaws of Life and they're cutting through vehicles, the high-voltage cables are also routed under the centre of the vehicle, so even though the power is cut off, they're not located anywhere near the doors or any area where they'd normally cut through."

Toronto Fire Services confirms that hybrids don't pose any unique hazards in crashes, whether to vehicle occupants or to first responders. Rescue personnel are familiar with hybrids and no matter what the vehicle they always "peel and peek" – pulling away trim to ensure no cables, fuel or brake lines, or airbag components are in the way – each and every time before cutting any metal.

All manufacturers share their schematics and safety procedures with first responders, who can access them at the scene through software in their rescue vehicles. Automakers also make vehicles available for rescue training.

Along with cables, the storage battery is also isolated. Farag says that the battery pack is sealed to the point that the car can be submerged in water and nothing will get in.

"There's no ability to get into the chemistry of the battery unless you make an effort to dismantle it, and there's no risk of electrocution," he says. Prius contains a nickel metal hydride (NiMH) battery pack.

"Our batteries use a gel electrolyte as opposed to a liquid electrolyte, which reduces leakage in a collision," Farag says. "There are no worries about leaks out of the battery."

Tesla, a California-based automaker whose all-electric sports car is scheduled to start Canadian deliveries later this year, uses lithium-ion (Li-ion) batteries. Lighter and longer-lasting than NiMH, they're also less stable, so special safety designs are used.

While Li-ion laptop batteries have occasionally overheated and caught fire, Kurt Kelty, Tesla's director of battery technologies, says that isn't an issue in these cars.

"We've got 66 temperature sensors to monitor it, and we've got a thermal system with liquid cooling, so when we're sensing high temperature, we're running coolant," he says.

"We've got special materials between the cells for safety. We have more space. In a laptop, they cram these cells into a very confined space, and they can't add the sensors that would add another level of safety. We've immersed them in flames from a puddle of gasoline, trying to mimic an accident with a (gasoline) car where afterwards the gasoline leaks out and catches fire. We've done impact tests, shock tests, vibration tests, we've even set cells on fire to see what happens to the cells next to them."

And as Kelty points out, most of us think nothing of driving vehicles containing large tanks of highly flammable gasoline and a source of ignition – neither of which are found on electric vehicles.

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