Imagine if you could charge up your electric car in only 10 minutes! That day could be right around the corner thanks to a new style of battery developed by Chao-Yang Wang at Penn State University. The design works by heating the battery to increase the reaction rate. The research has been published in Joule.
One of the factors holding back electric cars from mass adoption is charge time. At the moment, it takes too long for the battery to charge, especially in comparison to how long it takes to fill up a tank with liquid or gas fuel. Therefore, the only way to make electric cars more attractive to consumers is to develop a battery that can charge in a few minutes top. Wang’s battery can reach an 80% charge within 10 minutes. That gives the driver a range of roughly 300 kilometers.
The batteries currently on the market can’t do this because they have to be able to take in 400 kilowatts of power to charge that fast, which they can’t. When a battery charges rapidly, lithium ions tend to form plate-like deposits on the negative electrodes surface (when moving from the positive to the negative electrode). The deposits shorten the battery’s life.
To solve this problem, Wang and his colleagues tried heating the battery to a temperature too high for lithium plating to form. For this, they took a commercially available industrial battery to the test. They inserted micron-thick nickel foils in a stack of electrode layers, which allowed the electrode to heat up in under 30 seconds — this procedure allowed for ions to swiftly move into the negative electrode without causing plating on its surface.
Next, they tried out a range of different temperatures to see how well the cells worked at either 40°C, 49°C or 60°C. They compared the battery’s performance with a control battery charging at 20°C.
They discovered that at 20°C, the battery could maintain fast charging for just 60 cycles, at which point the lithium plating led to problems that significantly diminish performance. On the other hand, heating the electrode to 60°C gave the battery the ability to recharge up to 2500 cycles without the build-up of lithium plating that hinders performance. A battery with that kind of performance would provide 14 years of use or around 750,000 kilometers of life, said Wang.
The team’s findings suggest that there are benefits in short bursts of high temperatures. If the heating up of the battery is only for a short time, it doesn’t damage the battery. On the contrary, it makes it better. Now, the team plans to develop the design further. Their goal is to create an even better battery that can charge in only five minutes!
