In some examples, an implantable medical device (IMD) comprises an electrochemical cell compartment that may define a barrier between an inside of the compartment and an outside of the compartment. The IMD may include an electrically conducting pad. The IMD may comprise an electrically conducting pin coupled to the pad. The pad may include top and bottom sides. The pin may extend from the bottom side of the pad. The pad may be positioned outside of the compartment and the pin may extend through an aperture in the compartment from inside the compartment to pad positioned outside of the electrochemical cell compartment. The IMD may include an electrically insulating material surrounding the aperture and between the bottom side of the pad and the compartment. The insulating material may insulate the pad from the barrier and form a seal between the inside of the compartment and the outside of the compartment.