Lithium-ion batteries do not like the cold environment. Under 10 degrees Celsius, traditional lithium-ion batteries cannot be recharged quickly, which is a serious problem for electric vehicles in many areas.
In Scandinavian Pen., electric cars must be equipped with a small heater in the battery box, while in California the heating devices are significantly larger than those in Minnesota and Canada. The team, led by Chao-yang Wang, head of the research Center for electrochemical engines at Penn State University, has developed a new type of battery that can be used to avoid the energy loss of temperature at the freezing point by heating itself.
The principle is the same as that of a fast charging station, but it allows the battery to be recharged in 15 minutes even when the ambient temperature is lowered to 零下43摄氏度. The battery connects one end of a nickel sheet to the negative, and the other end extends to the third extreme port outside the battery. When the temperature sensor connected to the switch detects that the ambient temperature is reduced to about 25 degrees Celsius, it passes through the switch to control the current through the nickel plate.
Resistance allows the nickel plate to heat up and provide the battery with temperature from the inside. Once the temperature rises above room temperature, the battery's switch will automatically shift the current to charge the battery directly.
That means we don't have to replace the charging station, Wang says, just to control the heating and recharging in the battery, without having to adjust the charging device. In a report published in the journal Proceedings of the National Academy of Sciences, the researchers claimed that their prototype batteries were able to withstand a quick 15-minute charge of 4,500 times at 0 degrees Celsius, and that the energy loss was only 20%. This means that the battery life will reach 12.5 years.
By contrast, a conventional battery with a 20% energy loss can only withstand 50 times of recharging. The researchers say the innovative technology also makes batteries safer. Charging lithium-ion batteries at 10 degrees Celsius can lead to the accumulation of lithium ions on the anode surface, which can generate short-circuit, heat loss and ignition risks. The researchers say the unique, fast-charging method allows manufacturers to create lighter and safer small batteries for electric vehicles.
