How extreme cold affects vehicles and batteries
The Midwest is in the grip of record-breaking extreme cold this week, and it won’t just impact people. Vehicle engines and batteries are susceptible to these conditions. University of Michigan researchers are available to discuss these issues.
Anna Stefanopoulou is a professor of mechanical engineering and director of the U-M Energy Institute. She can discuss how vehicle batteries behave in extreme temperatures. In a recent paper, she and colleagues explored best practices for preparing to start a vehicle battery in sub-zero weather.
“Batteries are weak when they are cold. They are like humans,” she said. “At cold temperatures, it is important to have plenty of energy left so you can start. Don’t think that being near an outlet to charge will get you out of trouble.
“Our recent work shows that at low temperatures, you cannot charge, and it will be faster to discharge to warm up a bit the battery so your battery can safely accept the charging. So again, you need to leave plenty of charge to be able to start and go!”
This paper is titled “An Energy-Optimal Warm-Up Strategy for Li-Ion Batteries and Its Approximations.” It is published early access in IEEE Transactions on Control System Technology.
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Margaret Wooldridge is a professor of mechanical engineering. She can discuss how vehicles, including electric vehicles, respond to extremely cold weather.
“If you have an electric vehicle, or a cell phone for that matter, you have likely noticed the effects of the cold on your battery charge,” she said. “The colder temperatures reduce the time to discharge the battery, thus reducing the range of electric vehicles on a single charge.
“Diesel and gasoline engines produce a lot of waste heat which is used to heat the passenger compartment of vehicles in winter. EVs do not have comparable levels of waste heat, and have to use supplemental heating systems for the passenger compartments. This additional use of electric power with also lead to faster drain on batteries.”
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Andre Boehman is a professor of mechanical engineering and director of U-M’s W.E. Lay Automotive Laboratory. He can discuss why vehicles behave differently in cold temperatures.
“Engine coolant takes longer to heat up, which can mean that it takes longer for your vehicle’s heater to start warming your car. Fuel tanks or lines that are contaminated with water can result in fuel line icing that restricts flow to the engine,” Boehman said. “Diesel vehicles should be properly winterized. But when temperatures get extremely low, you run the risk of having the fuel form a wax, primarily from the ‘paraffin’ compounds in the fuel. This can clog your fuel filter and restrict flow to the engine.
“Because your lubricant needs to flow through many parts of the engine to allow the rotating and sliding metal components to slide more easily, cold lubricant may not flow as readily throughout the engine. This could lead to wear within the engine over a sufficient number of very cold starts, and is another reason to keep a block heater on your diesel engine.”
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Robert Hampshire is an associate professor of public policy and a research associate at the U-M Transportation Research Institute. He can comment about how smart infrastructure responds in these cold temperatures.
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