A few days back, we talked about a research by MIT scientists, involving an entirely new material that can store solar energy during the day and release it as heat by night-time. Being highly transparent, the substance could be used to de-ice windshields and prevent snow buildup. Winter months usually usher in a host of car problems, particularly pertaining to battery performance. As part of another new project, a team of scientists from Penn State University and EC Power has developed an all-climate Li-ion battery that is capable of self-heating at temperatures below 32°F (or 0ºC).
Cold weather is one of the worst enemies of batteries, often causing extreme power loss leading to slower charging. While this holds true for all kinds of batteries, such problems hardly affect the performance of small electronic gadgets, like laptops, smartphones and so on. In case of electric cars, however, subzero temperatures result in limited regenerative braking, and up to 40-percent decrease in the vehicle’s cruise range. Dead batteries are a common occurrence during winter; an issue that necessitates larger and more expensive battery packs. Speaking about the project, Chao-Yang Wang, a professor of materials science and chemical engineering at Penn State, said:
It is a long standing problem that batteries do not perform well at subzero temperatures… We don’t want electric cars to lose 40 to 50 percent of their cruise range in frigid weather as reported by the American Automobile Association and we don’t want the cold weather to exacerbate range anxiety. In cold winters, range anxiety is the last thing we need.
For the research, recently published in the Nature journal, the scientists have developed a special lithium-ion battery that automatically heats itself when faced with freezing temperatures. According to the team, it weighs around 1.5-percent more than the base battery, and costs only about 0.04-percent of the latter. What is more, it is capable of going from -4 to 32°F in less than 20 seconds, and from -22 all the way to 32°F in under half a minute. Compared to regular Li-ion batteries, the new technology consumes just 3.8-percent (when going from -4 to 32°F) and only 5.5-percent (from -22 to 32°F) of the cell’s total capacity.
The all-climate battery contains a 50-micrometer-thick nickel foil that connects to the negative terminal on one end. The other end of the foil extends outside the cell, forming a third terminal. When turned on, a switch fitted with a temperature sensor causes the electrons to travel through the foil, thus completing the circuit. The resultant resistance heating warms the foil and also the inside of the battery. When the battery temperature reaches 32°F, the switch gets turned off automatically, bringing the setup back to its normal state. As the scientists point out, nickel is both inexpensive and incredibly efficient as a resistance-heating element. Wang added:
Next we would like to broaden the work to a new paradigm called SmartBattery. We think we can use similar structures or principles to actively regulate the battery’s safety, performance and life.
According to the researchers, the new technology could greatly reduce “range anxiety” among electric car owners.
Source: Penn State University