As I gazed out the window of a puddle jumper descending from Stockholm into Lulea, I was struck by the breathtaking sight of frozen seawater for the first time in my life. Contrary to my expectations for mid-February at the northern tip of Sweden, the landscape was not as blanketed in ice as I had imagined. My mission? To experience the thrill of driving electric Polestar vehicles on the icy expanse of Stor-Skabram lake, located near the remote outpost of Jokkmokk, which lies well above the Arctic Circle. The unusually mild weather reminded me of the pressing issue of climate change, a significant narrative thread woven into the fabric of the electric vehicle industry.
Engaging in a day of maneuvering cars on ice and snow is an exhilarating experience for any driving enthusiast. However, this winter testing is more than just fun; it is vital for automotive manufacturers. They rely on such conditions to perfect the traction and stability control systems of their vehicles, ensuring they perform optimally in harsh winter climates. For electric vehicles (EVs), winter testing introduces a unique set of challenges. Unlike traditional vehicles, EVs cannot completely disable their electronic controls because their electric motors can deliver instantaneous torque, which can lead to loss of traction.
To mitigate this, the software in EVs utilizes a combination of wheel speed sensors, regenerative braking, and accelerometers that monitor yaw rates. Each Polestar model must balance responsive output to driver input with performance and safety. Additionally, battery performance during cold weather is a significant concern, as chemical cells do not operate as efficiently in frigid temperatures compared to their mechanical counterparts.
Given its Scandinavian heritage, Polestar places a premium on addressing these winter challenges, even as it operates under the Geely umbrella. Despite my initial ethical hesitations about the carbon footprint associated with flying journalists to the Arctic for winter testing, my concerns quickly faded as I took to the frozen lake. The ice, approximately a meter thick (39.3 inches), felt precarious beneath the weight of the EV, yet the local experts assured me that ice as thin as 25 cm (9.8 in) is sufficient for driving.
This winter, Polestar has set up three distinct test circuits in Jokkmokk, where I spent the day alternating between the Polestar 2, 3, and 4 models. Each vehicle is equipped with winter tires featuring 2-millimeter studs, designed for optimal traction while allowing for thrilling slides. I found myself particularly enamored with the Polestar 4, which exhibited impressive dynamics that made drifting enjoyable, despite my previous preference for the 2 and 3 on traditional roads.
Curious about battery performance, I pressed the throttle and reveled in the experience of drifting across the ice. However, I wondered if the low temperatures were diminishing the vehicle’s range. After each driving session, I consulted with Beatrice Simonsson, Head of Product, who explained how Polestar ensures that winter weather does not compromise EV performance. The company utilizes NMC (lithium nickel manganese cobalt) batteries with prismatic cells, unlike the cheaper LFP (lithium iron phosphate) batteries many competitors are adopting.
Polestar maintains optimal battery temperatures using a heat pump and a coolant system that circulates 20 liters (5.28 gallons) of coolant, specifically regulating battery temperatures. Interestingly, Simonsson revealed that battery pre-conditioning mainly focuses on the comfort of passengers rather than warming the batteries themselves. At 0° C (32° F), the heat pump’s efforts may only yield a slight increase in range, making it less advantageous for short trips.
In extreme temperatures, sometimes dropping to -30° to -35° C, the motors of Polestar vehicles perform admirably, as EV range largely hinges on cell chemistry rather than mechanical design. NMC cells can charge efficiently even in colder conditions, though prolonged exposure to freezing temperatures can temporarily affect charging and output performance. Notably, Polestar has not identified a minimum temperature where EV capabilities would cease entirely.
The distinctive driving dynamics of each Polestar model became evident as I navigated the circuits. The Polestar 3 faced the most challenges, struggling with its heavier weight and a complex array of variables affecting its performance. Under the guidance of Joakim Rydholm, Head of Driving Dynamics, I learned that the vehicle's accelerometers play a crucial role in low-traction scenarios, blending regenerative braking and power output to maintain control.
Throughout the day, I discovered that initiating drifts with momentum was far more effective than abruptly accelerating. This technique was particularly advantageous in the Polestar 2, which is approximately 1,000 pounds (454 kg) lighter than the 3 and 4 models. Additionally, I had the opportunity to experience ride-alongs in specially modified Arctic Circle editions of Polestar vehicles, equipped with racing seats and upgraded suspension.
As I navigated the icy terrain, it became increasingly clear that electric vehicles like Polestar can not only thrive in the harshest conditions but also offer an exhilarating and engaging driving experience. The journey underscored the potential of EVs, proving they can be both sustainable and fun, even on the frozen lakes of the Arctic.
