A battery module, comprising: - a lithium ion battery cell disposed within a housing of the battery module, the lithium ion battery cell comprising: - a casing enclosing active components of the lithium ion battery cell, the active components comprising an electrolyte and an electrode assembly in contact with the electrolyte, wherein the casing comprises a protrusion disposed at a top of the casing and the protrusion defines an opening in the casing; - a terminal (60, 62) electrically connected to the electrode assembly, wherein the terminal (60, 62) comprises an electrical contact extending through the opening in the casing, and wherein the protrusion of the casing comprises a cylindrical extension defining an annular region that is substantially co-axial with the electrical contact; - a primary sealing component disposed against the electrical contact to seal the electrical contact against the casing; - a secondary seal disposed around the electrical contact and against the primary sealing component, wherein 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 - a compressive seal disposed around the cylindrical extension and a first portion of the electrical contact, wherein the secondary seal is disposed against the primary sealing component and around a second portion of the electrical contact, the second portion being further away from the active components of the lithium ion battery cell than the first portion. - a lithium ion battery cell disposed within a housing of the battery module, the lithium ion battery cell comprising: - a casing enclosing active components of the lithium ion battery cell, the active components comprising an electrolyte and an electrode assembly in contact with the electrolyte, wherein the casing comprises a protrusion disposed at a top of the casing and the protrusion defines an opening in the casing; - a terminal (60, 62) electrically connected to the electrode assembly, wherein the terminal (60, 62) comprises an electrical contact extending through the opening in the casing, and wherein the protrusion of the casing comprises a cylindrical extension defining an annular region that is substantially co-axial with the electrical contact; - a primary sealing component disposed against the electrical contact to seal the electrical contact against the casing; - a secondary seal disposed around the electrical contact and against the primary sealing component, wherein 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 - a compressive seal disposed around the cylindrical extension and a first portion of the electrical contact, wherein the secondary seal is disposed against the primary sealing component and around a second portion of the electrical contact, the second portion being further away from the active components of the lithium ion battery cell than the first portion. - a casing enclosing active components of the lithium ion battery cell, the active components comprising an electrolyte and an electrode assembly in contact with the electrolyte, wherein the casing comprises a protrusion disposed at a top of the casing and the protrusion defines an opening in the casing; - a terminal (60, 62) electrically connected to the electrode assembly, wherein the terminal (60, 62) comprises an electrical contact extending through the opening in the casing, and wherein the protrusion of the casing comprises a cylindrical extension defining an annular region that is substantially co-axial with the electrical contact; - a primary sealing component disposed against the electrical contact to seal the electrical contact against the casing; - a secondary seal disposed around the electrical contact and against the primary sealing component, wherein 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 - a compressive seal disposed around the cylindrical extension and a first portion of the electrical contact,