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A unique platform to test battery technology

The little yellow car, known as A2B, on its first major run since major changes to its battery-powered drivetrain that might dramatically improve EV performance, range and longevity.

  • posing-with-battery-pack

University of Toronto engineering experiment boosts car’s power, range

The test drive made Olivier Trescases and Leo Shao just a bit nervous.

They were taking the little yellow car, known as A2B, on its first major run since major changes to its battery-powered drivetrain that might dramatically improve EV performance, range and longevity.

The early part of the 61-kilometre route wound through residential neighbourhoods. When that went well, Trescases and Shao ventured onto the 401.

With a new power source added to the battery pack and their own controller and highly complex computer program to manage the system, there was a slight chance things could go wonky.

But no worries: Years of research and development at the University of Toronto had, indeed, eliminated glitches and the car was ready to roll.

The A2B was created by Toronto businessman Steve Dallas — his attempt to develop a Canadian EV. He started the project in 2005 and had the car on the road four years later.

It was ahead of its time, but incorporated what has become conventional EV technology, including a 29-kWh lithium-ion battery pack that combined with an electric motor to produce a 200-kilometre range and top speed of 115 km/h.

Dallas — president of Toronto Electric Co. Ltd., which makes electric winches and cranes — began collaborating with the university’s engineering faculty five years ago.

In 2013, Trescases acquired the car. An assistant professor in the department of electrical and computer engineering, he and several students had been working on improvements to EVs, based on adding an ultracapacitor to the battery pack.

The A2B provided a unique real-world platform to test their ideas, he says.

“No one else has access to this kind of car. It’s an opportunity to test what would be virtually impossible for a university to do if it had to build from scratch.”

Lithium-ion batteries suffer when they take in or discharge large bursts of energy. That’s especially true when they operate in low temperatures.

To reduce the damage, they’re designed to operate well below their capacity. Still, they endure destructive extremes.

Ultracapacitors can store far less energy than batteries but they’re fine with power bursts.

So, the researchers combined the two, using their own high-efficiency power converter.

Basically, the ultracapacitor eliminates extreme loads on the battery: It accepts the regenerative energy surges as the car slows or brakes, and releases it during acceleration. Meanwhile, the battery can hum along happily, without highs and lows.

The ultracapacitor not only increases the use of regeneration energy but also allows more battery capacity to be employed. These advantages boost acceleration by about 30 per cent and range by 25 per cent.

The system should also extend battery life, Trescases says: “That’s the million-dollar question.” He and his students aim to answer it through laboratory tests.

The improvements are huge compared with the incremental gains being made through research to improve batteries themselves.

Trescases’ group has designed a computer program that expands the benefits by letting the system anticipate driving conditions, using GPS.

If it knows a stop is imminent and the ultracapacitor already contains energy, it can transfer some to the battery, opening room for regeneration energy. It could make similar adjustments when approaching hills or other demanding conditions.

Of course, all this is easier said than done: The program that runs the system, written by Shao for his master’s degree, must instantly, repeatedly and flawlessly assess the state of the battery and ultracapacitor and the motor’s needs, and manage the power flows accordingly.

It is, Dallas says, “mind-bogglingly complicated.”

Ultracapacitors are expensive, although that could change with mass production. The new system also fills the A2B’s limited luggage space, mainly because of the cooling and controlling devices that support the ultracapacitor.

The future will bring further refinements and, perhaps, cold-weather tests and research into combining ultracapacitors and fuel cells.

Does the research have commercial prospects?

“The project is being undertaken in the spirit of openness instead of commercialization,” Trescases says. “Our immediate goal is to publish, and facilitate Canadian companies to improve EV technology for the benefit of everyone.”

wheels@thestar.ca

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  • A unique platform to test battery technology MAILMASTER __Subject: Photos for Gorrie column, June 21 On 2014-06-13, at 5:08 PM, Peter Gorrie wrote: U of T Masters student Leo Shao (right in top photo) and Olivier Trescases, an assistant professor in the department of electrical and computer engineering, with the A2B, an electric car designed by Toronto businessman Steve Dallas. Shao and other students have modified the "Yellow Car" by the addition of an ultra-capacitor, shown in the trunk in the middle and bottom photos. This month, Shao and Trescases successfully completed the first major test drive. Shao wrote the computer program that makes it work. Photos shot by Peter Gorrie, for June 21 Green Wheels column. Gorrie-YellowCar-1.jpg Gorrie-YellowCar-2.jpg Gorrie-YellowCar-3.jpg

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