Around 12 months ago we looked at an innovative prototype battery for electric vehicles that was highly promising on several fronts, including being able to be recharged in just 10 minutes for hundreds of miles of range. The researchers behind it have continued tweaking their approach, and have added a couple more desirable attributes to the list, including a price point they say is on par with internal combustion engines.
Developed by a team of chemical engineers at Penn State University, the original battery was able to be charged in a relatively short space of time by subjecting it to what the scientists considered extreme temperatures. Normally, lithium batteries need to operate within a certain temperature range. When conditions are too cold, lithium ions form dangerous spikes on one of the electrodes, while when too hot, it can lead to other forms of degradation.
The Penn State University team found a way around this, and took their battery into “forbidden” territory by charging it at “extreme” temperatures, heating it to 60° C (140° F) and then quickly cooling it. This was enabled by a thin nickel foil that attaches to the negative terminal and quickly warms the battery, with these short and sharp bursts of heat enabling the device to charge up far more efficiently.
So much so, it could be charged up enough to offer an electric vehicle a range of more than 200 miles (320 km) in just 10 minutes. This fast-charging capability, meanwhile, allows the team to downsize the device, while still offering a useful range.
In the time since, the researchers have continued experimenting with the design of their innovative battery, including investigating alternative materials for the cathode. Where the original used a nickel-cobalt-manganese, the new and improved version uses lithium-iron-phosphate instead.
The battery works on the same principle, using a thin nickel foil to rapidly hit extreme temperatures and charge up before cooling again, but these new materials offer a couple of advantages. The first is that they do away with cobalt, which is a common objective in battery research as the material is rare, expensive and mining it is detrimental to the environment and human workers. The second is that these materials are low cost.
“The fundamental difference is that this work solely aims at reducing battery cost so that it becomes affordable for mass-market electric vehicles,” lead researcher Chao-Yang Wang tells New Atlas. “Indeed, we have created a 40-kWh battery in this work, which has 200-mile range per charge and then extended by 10-minute fast charge. In other words, we have used convenient, fast recharge to downsize the vehicle battery and drive the cost down to US$3,500, which is on par with gasoline engines.”
Wang also says that the battery can produce 300 kW peak power, which is enough to propel an electric vehicle from 0 to 60 mph (96.5 km/h) in three seconds, and that the new design still proved very safe in their testing and should last for two million miles (3.2 million km) of electrified driving. While there is a lot more research and development to take place before that happens, the researchers believe they’ve got the makings of a game-changing device.
"This battery has reduced weight, volume and cost," says Wang. "I am very happy that we finally found a battery that will benefit the mainstream consumer mass market."
The research was published in the journal Nature Energy.
Source: Penn State University
