Norfolk Southern Railway No. 999, which opened a few years ago, is the nation’s first completely electric, battery-powered locomotive. While it certaily has significant upsides when compared to diesel trains, there are still some kinks to be worked out. The primary of which is the reliance on lead-acid batteries, and their limited battery life. But now, thanks to new research, new cost-effective methods to prolong the lifespan of these batteries have been developed.
The Penn State researchers had been looking for a sple and cheap way, not dependant on expensive hardware, to improve battery performance. What they came across was a way to reverse “sulfation,” which is a degradation that occurs from repeated charging and recharging, and results in an accumulation of lead sulfate.
The researchers “cycled a lead-acid battery for three months in the same way it would be used in a locomotive. They used a process called electroimpedance spectroscopy and full charge/discharge to identify the main aging mechanisms. Through this, the researchers identified sulfation in one of the six battery cells. They then designed a charging algorithm that could charge the battery and reduce sulfation, but was also able to stop charging before other forms of degradation occurred. The algorithm successfully revived the dead cell and increased the overall capacity.”
“We desulfated it, and we increased its capacity,” said Chistopher Rahn, a professor of mechanical engineering. “We didn’t increase it all the way to brand new. We weren’t able to do that, but we did get a big boost.”
The cell capacity was increased by 41% and the overall capacity of the battery by 30%. The researchers are now currently working on a method to stop the development of sulfation in the first place.
Norfolk Southern’s locomotive No.999 began development in 2008, and since then has been serving as a testing ground for the development of battery technologies that could potentially lead to “energy savings and emissions reduction” for the company.
The research was detailed in the newest issue of the Journal of Power Sources.
The wide-scale adoption of electric locomotives in the US, replacing primarily diesel-fueled locomotives, could go a long way towards reducing carbon emissions in the country. If any truly effective plan to significantly limit carbon emissions in this country is ever developed, technologies and improvements such as these will be necessary, and likely invaluable.