A lithium ion battery cell includes a prismatic casing enclosing active components of the lithium ion battery cell. The lithium ion battery cell also includes a terminal having a terminal post extending through an opening in the casing and electrically connected to the active components; a primary sealing component configured to seal a first portion of the terminal post against the casing; and a secondary seal disposed around a second portion of the terminal post and against the primary sealing component. The secondary seal is formed from a curable adhesive resin and is configured to resist egress of the electrolyte out of the lithium ion battery cell and is configured to resist ingress of moisture into the lithium ion battery cell.