Everything seems go slower in cold weather, including in chemistry. Old starter batteries are less enthusiastic, and can fail completely. Our mothers may have once told us wrap up and keep warm. This same simple truth applies to electric vehicle batteries in winter.
Freezing Winters Slow Electric Vehicle Batteries
Cold temperatures cause chemical reactions to slow in all types of popular batteries. Electrical resistance increases in their metals, including lithium, cobalt, nickel, lead, and so on. The battery becomes sluggish. It takes longer to charge and delivers less power until it warms up.
The chemistry inside lithium-ion batteries is quite complex. Although in simple terms these store their energy in molecules we call ions. These ions move back and forth through a liquid electrolyte as they discharge and recharge. The resistance in the liquid increases when the weather is cold …
These factors boil down to diminished performance from electric vehicle batteries in winter, and in particular shorter driving ranges. The ‘lost’ driving range returns when the weather is warmer, but this does not help if you are setting off on a long winter journey. The solution can be as simple as keeping the battery warm!
Warming EV Batteries in Cold Weather
Batteries naturally warm up when we use them, especially while charging. Fortunately, there are things we can do to prepare EV batteries for cold mornings. We could make a good start by storing them overnight in the garage under a car cover, or connecting the garage to our home heating.
But this is not always possible. What else can we do? The best option might be to purchase an electric vehicle with a heat pump, if you don’t already have one. So how would this work in winter?
Heat pumps warm electric vehicle batteries in winter by reversing their cycle, drawing in air from outside, and concentrating it. This slightly warmer air passes through the battery’s coolant loop, gently raising battery temperature. This allows it to charge and deliver power more efficiently, even below freezing temperatures.
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Not Just Batteries Crank Slower in Winter
