Richard S. Baldwin

Glenn Research Center, Cleveland, Ohio

Impedance Measurement Cell Fabrication

A modified 2325 coin cell configuration was employed as the cell fixture for conductivity and impedance (i.e., electrical resistance) measurements of electrolyte-wetted separator samples over the desired temperature range. This test configuration was selected as it provides a constant and reproducible pressure applied to a separator sample in a sealed-cell environment. The coin cell can and internal parts were initially inspected for any defects, sharp edges were removed from the stainless steel spacer electrodes and the metallic cell components were cleaned with solvent in a dry-room environment. The cell components were transferred to an argon-atmosphere glovebox for cell assembly. The sample separator material, which was previously dried for 12 hr under vacuum at 60 °C and stored in the glovebox, was punched to form the sample disc geometry, and its thickness was measured with a Mitutoyo Series 543 digital indicator, or equivalent.

After the addition of sufficient liquid electrolyte (~40 µl) to completely wet the separator sample and after the correct stacking sequence of the coin cell internal parts, as shown in Figure 4, a pneumatic coin cell crimper (Xiamen Tmaxcn Inc.), as shown in Figure 5, was used to seal the coin cell while inside the inert-atmosphere glovebox.