Watch Rivian R1T Electric Truck Cold Weather Testing In Minnesota


Rivian released a very interesting blog post and video about the cold-weather testing of its upcoming Rivian R1T electric pickup.

The prototypes of the vehicle are undergoing extensive testing at North America’s largest cold-weather testing facility in Baudette, Minnesota.

If you don’t see the YouTube video due geographical restrictions, please check it on the Rivian’s Vimeo channel (embeded below) or on Rivian’s website.

The site was previously a United States Air Force radar base, but now it’s a huge automotive testing facility, which “offers 25 courses, including a multitude of autocrosses, snow and ice test tracks, a litany of vertical grades, a slush pool and other surfaces designed to capture winter weather at its worst”.

With DC fast chargers installed, it’s also ready for EV testing:

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

As we know, lithium-ion batteries, just like humans, “like” to remain at moderate temperatures. This requires putting a lot of effort into the thermal management system of the battery.

The first piece of advice for EV owners is to plug in overnight if you can (to recharge and provide energy to heat the battery). According to Rivian, if the R1T is “plugged in all night, you can hop in and drive with very little compromise to performance at even -40° F [-40°C]”.

In the case of Rivian, the thermal management system tries to keep the battery cell temperature above 14°F (-10°C). Interestingly, there are no dedicated electrical heaters, but rather a smart utilization of the inverter and motor to generate heat while the vehicle is stationary (or use waste heat when the vehicle is in use).

“In extremely cold conditions we use some battery energy to keep the cells in our battery above 14°F to provide controlled vehicle performance. Some EVs have electrical heaters to heat the battery up, which is another component — more cost, more mass and a drain on electrical supply.

Instead, we’re using our inverter and motor to generate heat — even while stationary our traction system can generate substantial heat for the battery. And we use that heat to warm the battery to the point where it can deliver full performance. Our battery is uniquely designed to operate in super cold conditions, all the way down to an ambient temp of -40°F.” – Laura Controls Integration Engineer

Rivian Battery Technology Facilities, Irvine, CA

Rivian Battery Technology Facilities, Irvine, CA

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Rivian battery cooling (image: George Bower)

The double-stack battery pack has a central cold plate (for axial heating or cooling):

“Our batteries use an axial cooling method via a central cold plate — a unique design feature of our pack — which is a highly efficient way to both heat and cool the battery. This system uses the minimum amount of energy possible to keep the cells at their optimum temperature, which is particularly important if the vehicle has been unplugged in extremely cold conditions.”

Rivian explains that when the vehicle is plugged into a home AC charging station, it can replenish about 25 miles of range per hour. If the battery is cold, and there is a necessity to generate heat to warm the cells, then the rate temporarily halves. The good news is that after about an hour of heating, the rate returns to its maximum of 25 mph.

At -40° F (-40°C), the vehicle should operate fine, but will need roughly 20 minutes of battery heating to be able to deliver full power.

“Our vehicles have been designed to minimize any performance or range impact from extreme cold temperatures. If getting in the vehicle after a long cold soak at -40F, the vehicle will operate fine but will take about 20 minutes for the battery to warm itself up and be capable of delivering full power and battery performance. The vehicle range prediction displayed to the driver will take into account the temperature, driving conditions and cabin heating considerations to give an accurate display of vehicle range from the remaining battery energy.” – Richard VP Propulsion Powertrain

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

Rivian R1T Cold Weather Testing (© Elliot Ross)

The thermal management system is not the only topic of testing. Rivian must test everything else as well:

“We are simultaneously developing traction control, torque vectoring, regen slip control, anti-lock braking and electronic stability control with the goal to get them all to play nicely together — especially in the snow.” – Max Director of Vehicle Dynamics

 



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