Electric Avenue
A revolutionary power storage technology is poised to help Toronto’s ZENN Motor Company ride the crest of a new wave of electric vehicles
By Treena Hein | April 10, 2008
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Michael Bergeron has a dream job and he’s enjoying every minute of it. As vice-president of engineering at Toronto-based ZENN Motor Company for the past two years, Bergeron has been happily applying himself to the technical challenges of creating and improving ZENN’s low-speed electric vehicle (EV), one of only a handful of vehicles design and manufactured in Canada.
Now, the eight-year-old company is on the verge of taking its product to the next level. The first step will be integrating a potentially revolutionary technology that could set this small Canadian car company in a class of its own, in an EV market that’s becoming increasingly crowded.
But Bergeron’s team—like everyone else in the automotive world—is waiting for the answer to a rather large question, one that is generating both electric tension in ZENN’s media coverage and serving as the burning source of much automotive and technology blog speculation: Will the capacitor units ZENN hopes to use ever be delivered to the company—and deliver on promises made?
And there’s another million dollar question, which is of course, “When will EVs be for sale in Canada?” Bergeron is currently working on a highway-capable model but the answer to that may be just as challenging.
Wise Use of Resources
The matter, however, of how the ZENN engineering team (five engineers plus support staff) creates their cars is more easily addressed.
“Our concept is one that is very common in the EV business right now,” Bergeron says. “Basically, we work with an automotive firm who provides us a host vehicle. We buy the vehicles without drivetrains and put our drivetrains in.” ZENN’s low-speed platform is provided by Micro Car of England; the new highway platform is currently being chosen.
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The Zenn's drive train and lead acid batteries produce a top speed of 40 KPH and a vehicle range of 48-80 km. |
Next comes selection of the drivetrain, which Bergeron says is one of the toughest aspects of the whole process, followed by matching the motor with a controller, integrating the other components and performing overall “tuning”—all accomplished digitally.
“We have all the CAD data on the host vehicle. In general, that’s in CATIA,” Bergeron says. The majority of the mechanical work—mostly checking bracket stresses and battery packaging—is outsourced, under ZENN direction, to CADmech, a Toronto engineering firm with automotive expertise.
“As a small firm, we have to be flexible in terms of the OEM we work with,” he says. “It’s very difficult for us to have seats of CATIA and Pro/E and SolidWorks, etc., but CADmech has them all, and every one of their engineers knows at least two CAD platforms.”
All the electrical engineering is done by the company’s engineering team using VeSys software, which Bergeron says allows one engineer to perform the work of three. In many cases, he says their level of engineering documentation exceeds that of the host vehicle from the electrical side.
“[Using VeSys,] you can create the vehicle schematics as well as the harness drawings and it links everything together … and then we can actually simulate it online,” he says. VeSys also allows the team to examine failure modes and generate various fault positions in order to do trouble-shooting from a servicing perspective.
Most of ZENN’s engineering testing is done at their St. Jerome, Que., manufacturing plant. “We were able to get an agreement with the town of St. Jerome and the Quebec Provincial Police to allow us to drive our vehicles and to test them [in town],” he says. “I can’t tell you how important that was.”
A New Automotive Engineering Ball Game
Designing EV’s obviously differs from traditional automotive engineering. The gearless transmission, for example, is “radically simplified,” Bergeron says. “As an example, you could have a fixed gear ratio differential of let’s say 7:1 or 5:1; you just hook your motor up to that, and basically you have a gas pedal.” The motor speed is dependent on the frequency generated in the system. “Essentially, for an AC drive [currently used in ZENN cars], the controller is what we call an inverter,” he says. “An inverter basically takes in a DC voltage so you can connect a battery or a capacitor or whatever to the input and it creates an AC sine wave of differing frequency … the faster the frequency, the faster the motor turns.”
Like many EVs, ZENN cars feature regenerative braking, although its ability to extend range is only a couple percent with chemical batteries. “When you suddenly throw a lot of energy back at batteries, it takes some time for the chemical reaction to reverse,” he says. “You absorb some of energy, but not all of it.”
Bergeron says what regenerative braking does address is handling issues. “You can do all kinds of neat programming by monitoring the brake pedal,” he says. “And obviously, you’re going to look at ways of configuring to enhance safety,” such as light brake response at very low speeds.
Trying different battery configurations has been a challenge because of the corresponding changes in weight distribution that in turn affect the suspension. The largest difference, however, between traditional automotive engineering and what Bergeron does is probably the demand for fast cycle time to address on-going customer feedback.
“One of the big issues for EVs is none of us are used to them because we don’t drive them,” he says. “Our sales and marketing folks are constantly looking at the market, trying to understand what people want and what’s preventing them from getting in a battery EV; that gets fed back, and we have to produce that for the vehicle.”
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ZENN Motors' St. Jerome, Que. manufacturing plant near Montreal: To date, the company has sold 256 units total in Europe, Asia and 45 of 50 U.S. states-but none in Canada. |
For example, Bergeron says in an EV’s no-motor-noise environment, customers often complain about the level of noise from outside the vehicle, especially while driving on rough terrain. Another recent feedback issue involved modifying the car’s charging port so that commercial customers can recharge at higher speed during lunch hour. The company also recently finished a project that incorporated an air conditioner.
“The market is still evolving, so there’s a little bit of perception of what people want versus reality,” Bergeron observes. “So we end up trying something and then we get feedback that we have to change it.” He says a lot of the feedback concerns car performance. “We’ll get ‘Gee, the acceleration’s great, but when I go to back up, it backs up too slowly,’ or ‘When I go into a corner, it does this’ … The interesting thing about that is you ask ten people, you’ll get ten different opinions, so we’re often in a position of trying to find the best of everything.”
The overriding challenge at ZENN right now, however, is creating a highway-capable model, which must meet much higher standards and possess features like power braking and steering. “There’s a whole host of things you get into with a fully functioning EV,” Bergeron says. “And there are solutions out there. It’s not rocket science, but the number of things you have to change just starts increasing. The faster the vehicle goes, there’s more function that you need to convert over. As with anything, there’s always seven different ways of doing it, and you’ve got to figure out the most effective way to do that, taking into account the amount of energy.”
Bergeron researched motors for their highway model from around the globe and recently short-listed about a dozen in preparation for their final choice. “It’s completely apples and oranges,” he says. “Everybody has some strength and some weakness and you’re trying to compare all these things and you have to put some science to it. That’s actually been a lot of fun, making sure we understand the criteria clearly.”
Capacitor Power
ZENN made waves last year when it purchased the worldwide exclusive licence to the capacitor technology of Texas-based startup EEStor for curb-weight vehicles up to 1,400 kg (e.g. Honda Accord size), and non-exclusive rights to use it in larger vehicles. ZENN also has worldwide exclusive rights to convert all existing internal combustion passenger vehicles to electric using EEStor technology.
Just how this technology works and how it will perform remains a mystery. EEStor claims that its breakthrough “Electrical Energy Storage Units” (EESUs) contain a capacitor that uses barium tinanate coated with aluminum oxide and glass, which will allow EVs to overcome all the limitations of chemical battery use. That is, capacitors potentially provide much shorter recharge time, longer range, lower weight and a much better tolerance of extreme temperatures. Their capacitors can apparently achieve capacitance of 1.0 MJ/kg, which is 100 times what existing commercial supercapacitors offer and about 30-50 percent more than lithium-ion batteries provide.
In addition to a capacitor, Bergeron says EESUs also feature a great deal of power electronics. “Obviously, you have a lot of energy in there that wants to get out very quickly, so you have to have something that manages the energy,” he says. “Basically, you have a very large capacitor and you have a buck-boost converter at the simplest level. It’s a very simple concept, and that’s what’s so beautiful about it. It is the Holy Grail for engineers and EV’s—a stable energy source that has a lot of capacity.”
Recharging ZENN cars with EESUs instead of batteries could be accomplished in several ways. There is regular-outlet overnight charging, or an outdoor/garage plug-in could be converted to 220 volts, which at 9 kW/h will charge a 15 kWh EESU in a little over an hour and a half. Another option takes the form of a device that draws electricity slowly overnight, and then charges the EESU in minutes on demand. Bergeron can also foresee quick-charging stations akin to gas stations, a model the public is familiar with. “There are all kinds of ways of doing this,” he says. “Of course, we’re focused on the vehicle, but we certainly believe that others will focus quickly on the energy delivery.”
Many have speculated that EEStor’s claims are exaggerated and have expressed doubts it will deliver. Indeed, EEStor has pushed back the date of when the capacitors should have been delivered to ZENN’s St. Jerome plant. However, EEStor’s credibility was boosted in January when the company signed a deal to supply their technology to Lockheed Martin, a large US defence contractor, for use in rugged military and security power packs.
So, while Bergeron can’t answer the question of when ZENN will begin receiving EESUs, he says, “We visit [EEStor] regularly, and we remain optimistic. They’re moving forward. Obviously we had hoped they’d be farther along than they are, but the approach that’s being taken is favourable to coming up quickly in production.
“Obviously we have a position with EEStor that’s very favourable to us, but we’re engineers,” he adds. “We have to look at all technologies and keep abreast of all technologies just to stay on top of things.”
The first EESUs to arrive at ZENN will have a capacity of 15 kWh (54MJ). Bergeron says that “even at that size, it weighs [35 to 40 percent] less than the lead-acid battery, so the vehicle’s going to get lighter, which is great, with four times the energy.”
Energy storage aside, those Canadians who would like to drive an EV must be patient. ZENN CEO Ian Clifford calls efforts to gain regulatory success “hugely problematic.” While the federal and British Columbia governments recognized low-speed EVs as legal in 2000, and ZENN received a National Safety Mark from Transport Canada late 2007, shortly thereafter Transport Canada added further restrictions. Clifford, in the meantime, is looking to South America, Asia and Europe. “We’ll go to where the market is,” he says.
Wherever they’re
sold, Bergeron believes there’s a definite benefit to
designing ZENN cars in Canada, particularly in the Toronto area.
“We have people coming to Canada from around the world with
unbelievable skills and it has been just a privilege to have such a
pool of talent available,” he says.
www.zenncars.com
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