Patent ID: 6493212
Filing Date: 2002-12-10
Classification: A61N

Abstract:
A hermetically sealed implantable medical device, comprising:a hermetically sealed housing; an energy source disposed within the housing; circuit means coupled with said energy source for selectively providing a charging current; and a substantially flat electrolytic capacitor disposed within the housing and connected to the circuit means to be charged thereby, the capacitor releasing gas during charging, the capacitor comprising: a hermetically sealed capacitor case defining an interior case chamber, the case having a base bounded by a base peripheral edge, a case side wall extending between the base peripheral edge through a side wall height to a side wall opening edge defining a case opening edge, and a cover hermetically sealed against the case opening edge to enclose the interior case chamber; an electrode stack assembly comprising a plurality of capacitor layers each comprising a cathode layer, an anode layer and a first separator layer stacked and disposed within the interior case chamber; a liquid electrolyte filling within the intelior case chamber; a fill port formed through one of the case side wall and the cover for filling the capacitor with the liquid electrolyte, the fill port shaped to comprise a fill port tube having a fill port tube lumen extending between interior and exterior tube ends and a fill port ferrule intermediate the interior and exterior tube ends, the fill port ferrule formed as a flange extending transversely to and radially away from the fill port tube, the fill port ferrule being mounted in an opening disposed in one of the case wall and the cover wall with the ferrule flange in sealing engagement therewith to locate the exterior tube end extending outwardly away from the case side wall or cover and the interior tube end within the interior case chamber; and a microporous material filling said fill port lumen and extending into said interior case chamber in a region surrounding said interior tube end, the microporous material allowing the escape of gas released during capacitor charging and discharging cycles while preventing escape of liquid or vaporized electrolyte.