Fabrication of Lithium-Ion Pouch Cells with Reversible Shutdown Membrane Separator
Keywords:Reversible Shutdown Membrane Separator
Lithium Ion Batteries
Three Active Electrode
Thermal Runaway Protection
MetadataShow full item record
Publisher:The Ohio State University
Series/Report no.:The Ohio State University. Department of Mechanical and Aerospace Engineering Honors Theses; 2020
Batteries that power electrical vehicles, especially the safety concerns and performance limitations, are of significant interest as the thrust for sustainable transportation continues. Li-ion batteries are prevalent in these vehicles and many consumer electronics due to their advantages over other battery chemistries. Thermal runaway is a major safety concern of batteries that can result in fires or explosions, and li-ion architectures are at a higher risk. Limited charge and discharge rates contribute to electric vehicles’ inability to fully compete with internal combustion engine vehicles. The objective of this research is to transition the use of a reversible shutdown membrane separator (RSMS) in a Swagelok cell to a pouch cell, an architecture used in commercial applications, and find a cost-effective alternative to gold in RSMS fabrication. Through a redox event, a RSMS can operate as an ion source or sink, which can internally and reversibly prevent thermal runaway or provide a power boost. A novel fabrication method was developed for a three-electrode li-ion pouch cell with a RSMS as a third active electrode. The RSMS shape was tailored for a built-in current lead and melt tape parameters were optimized for effective sealing between the lead and pouch. Once fabricated, charge-discharge cycling and real time testing of the pouch cell with a RSMS was performed to examine the cell charge-discharge cycling capacities and validate the RSMS worked reversibly for preventing thermal runaway or providing a power boost. Alternatives to gold, most of which are common in li-ion batteries (aluminum, nickel, aluminum/titanium, and nickel/titanium), were explored in the fabrication of the RSMS. Cyclic voltammetry was used to examine the electrochemical function and cyclabilities compared to gold. The charge-discharge cycling capacities of the cell with a RSMS were comparable to baseline cells for a reduced state membrane and lower for an oxidized state membrane. Real time results showed the RSMS could remove anode current for ~30-60 seconds to prevent thermal runaway or provide a power boost for ~60 seconds without changing the constraints of the power source or load. Nickel was determined to be a feasible candidate to replace gold due to fabrication ease and a reasonable filling efficiency of 31.9% compared to gold’s 42.5%. This is the first technique (to our knowledge) for fabricating three electrode pouch cells with a third active electrode. This fabrication technique for three active electrode pouch cells could be used for different third active electrodes to expand the capabilities of battery cells. The use of an active membrane separator could be extended to implement other types of active membrane separators instead of standard passive separators. Li-ion pouch cells or other battery architectures with a RSMS will provide enhanced safety with thermal runaway protection and improved performance capability with power boost functionality.
Academic Major: Mechanical Engineering
Ford through Ford-OSU Alliance
Items in Knowledge Bank are protected by copyright, with all rights reserved, unless otherwise indicated.