Electric & Hybrid Vehicle Technology • July 2021 • Making tracks

The struggle to maintain an optimum EV battery temperature usually involves sophisticated cooling circuits to dissipate prodigious amounts of heat. Not so for the Venturi Antarctica, a unique, six-person tracked vehicle that has been purpose-built for use by scientists at the Princess Elisabeth Antarctica research station.

For the team led by chief designer, Louis-Marie Blondel, the demanding ambient temperatures of around -58°F (-50°C) were the biggest influence on the design of the new vehicle. For the powertrain, which at its heart has two 60kW axial flow motors and a 370V, 52.6kWh lithium-ion battery pack from an Austrian supplier, that meant a complex thermal management system.

Dimensions: 3.46m (L) x 2.02m (W) x 2.18m (H)
Battery: 370V, 52.6kWh
Tracks: Camso, natural rubber on aramid belts
Motors: 2x 60kW axial flow
Suspension: multilink sprung suspension, two dampers per track
Range: 50km (31 miles)
Recharge time: 2h-18h depending on installation Minimum operating
temperature: -60°C (-76°F)
Weight: 2,500kg

“It’s impossible to charge the battery pack below 0°C [32°F], so we developed a specific system to heat it to reach this minimum temperature,” explains Blondel. “In our system, we use the heat from the motors to heat up the battery pack. We tried to maximize the thermal insulation [with a mixture of Polyurethane, fiberglass and silica-based Aerogel] so the vehicle doesn’t need as much power to heat up the system, making it as energy-efficient as possible.”

Antarctica has two cooling circuits: one for the motor that uses water/glycol and one for the battery pack, for which a dielectric fluid is used. Aside from the heat exchange between the two, an electric heater is on hand to bring the fluid temperature up when needed, powered by roof-mounted solar panels when possible. Cold plates are on hand to cool the fluid if required, fed with ice from the custom-made, natural-rubber tracks from Camso.

The vehicle that was recently unveiled is the third generation of Antarctica. The first prototype was unveiled in 2011, leading to extensive development of a second-generation vehicle that broke cover in 2018. The following year it was subjected to a rigorous testing program in British Columbia, Canada. Blondel notes that powertrain differences between that vehicle and the definitive Antarctica, which is now undergoing final testing, are few.

“Although the new battery pack is bigger, it’s the same cells,” he says. “We didn’t make any major improvements to the battery pack, nor to the thermal management, because we had validated this whole powertrain during the tests in Canada. We made improvements in the isolation of each component, but the biggest improvements were on the chassis side and to the bodywork.”

Each of the motors drives a wheel-mounted caterpillar track. A track broke during the Canadian tests, so this has been one area of attention in the subsequent two years of further development. The need for absolute reliability and minimal in-field maintenance at such a remote operating base has been a priority for the design team.

“Working on a major component like a motor in the Antarctic is a nightmare,” says Blondel. “The better option is to never have to do maintenance. The advantage of an electric vehicle is that you normally have less maintenance than with an ICE-powered one.

“If you have to work on the vehicle, you can do it easily,” he continues. “For example, we have tried to make every screw very easy to remove and have panels inside the car to provide direct access to specific components like 12V batteries or the controllers. We can plug a computer in to see if everything is working well and have fitted a lot of sensors to monitor each component.

“The goal will be to only have a maintenance check [in the field], for example, the coolant level or wheel grease, just to see if everything is good. The plan is to do the missions and in the end, to bring the vehicle back here [to Monaco] for maintenance. But, if necessary, we could use a workshop in Antarctica to change a track, for example. You could also remove the battery pack or another electric component from the vehicle to work on it.”

Extensive simulation work has been employed to validate mechanical components like the custom suspension ahead of physical testing. Blondel says it’s possible to get to about 75% of where they need to be in the virtual environment, but that physical testing is essential. At the time of writing, Antarctica was out testing in the South of France.

“We are working on some mechanical aspects of the vehicle,” he explains, “stressing the chassis and suspension. After that, we will go into a climate chamber to retest all the electronic devices. We will also redo some mechanical tests in a climate chamber.”

The target is to complete the program by October so that Antarctica can be on station, ready to start work on December 7.

What does a tracked polar research vehicle have in common with a Formula E racer or a land-speed record motorcycle? More than you might think, as it happens. Antarctica draws on Venturi’s Formula E race team for its vehicle control unit and modified brake software. Motor controls are derived from the record-breaking Voxan Wattman electric bike, which is about to be relaunched and for which Louis-Marie Blondel also serves as the development rider. “Venturi has a small team of engineers and mechanics working on deep projects, where everybody is very involved,” he says. “When we finish a project, we don’t turn the page and move on; we [keep in mind what we did] and try to improve. We have also worked with some suppliers for many years, so much so that it’s like we’re the same company.” He adds that learnings from the Antarctica include better correlation for the simulation software and the extensive development behind the joystick used to steer the vehicle.