The results of a new study led by two Binghamton University professors could reduce the production costs and increase product quality for large-sized lithium-ion batteries.
Lithium-ion batteries are used widely in consumer electronic devices and are increasingly powering large-scale applications, such as electric vehicles and grid-level energy storage. However, the change from smaller coin-sized cells to bigger “pouch” cells has posed challenges to battery manufacturers, because scaling up the manufacturing processes can lead to high costs and unstable product quality.
A key part of the manufacturing line is the adding of electrolyte, which permeates and fills the pores in the electrode. This “wetting” step can take several days or weeks depending on the cell chemistry. The long wetting process poses a distinctive bottleneck in the manufacturing process especially for large-size cells. To expedite the wetting process, the electrolyte wetting is usually conducted at elevated temperatures, thus requiring a great number of environmental chambers to be installed.
Poor electrode wettability results in extended manufacturing time and incomplete wetting. Incomplete wetting can lead to poor utilization of electrode capacity and, even more critically, to needle-like structures called dendrites on the electrodes that penetrate the separator and directly connect the anode with the cathode, creating internal short circuits and leading to serious safety issues.
In a study recently published by The Journal of Power Sources, Congrui Jin and Tim Singler of the Department of Mechanical Engineering at the Thomas J. Watson School of Engineering and Applied Science proposed an innovative approach based on in-plane liquid imbibition into a thin porous film that could accurately measure electrode wettability.
“Our technique overcomes the limitations of the classical wetting balance method and provides a quantitatively accurate understanding of electrolyte transport in porous electrodes,” Jin said. “It greatly helps optimize electrolyte formation and electrode design to achieve rapid and complete wetting.”
Despite the significance of rapid and complete wetting for lithium-ion battery production, reliable scientific investigation has been scarce. Often, only simple qualitative observations such as good, poor and fair were reported.
Jin and Singler’s new study improves the understanding of wetting behavior, which can have significant potential performance or economic impacts.