Polyimide protected battery feedthrough
First Claim
1. A method of protecting vulnerable surfaces of a feedthrough within a housing of an electrochemical cell enclosing a reactive chemical compound, the feedthrough comprising an electrically conductive ferrule, an elongated electrically conductive feedthrough pin, and annular glass insulator supporting the electrically conductive feedthrough pin spaced from the feedthrough ferrule, comprising:
- attaching the feedthrough ferrule of the feedthrough to a side wall of the housing to dispose the feedthrough pin extending through the side wall; and
coating the interior surface of the feedthrough insulator vulnerable to degradation upon contact with the reactive chemical compound with polyimide that forms a polyimide coating that tenaciously adheres to the vulnerable surfaces and is resistant to degradation by the reactive chemical compound.
1 Assignment
0 Petitions
Accused Products
Abstract
Vulnerable surfaces of feedthroughs employed in electrochemical cells or batteries, particularly miniaturized, high energy density primary batteries for implantable medical devices (IMDs), are provided with protective coatings to protect from degradation by the cell electrolyte or deposition of conductive materials bridging the feedthrough pin and ferrule. A liquid polyimide coating is applied to the vulnerable surfaces and cured into a substantially uniformly thick polyimide coating that tenaciously adheres to the vulnerable surfaces during subsequent welding and molding assembly steps. A further insulator is preferably molded in situ of a polymer adhere wells to the polyimide coating during molding. Gaps between the insulator and the polyimide coating are advantageously minimized.
-
Citations
24 Claims
-
1. A method of protecting vulnerable surfaces of a feedthrough within a housing of an electrochemical cell enclosing a reactive chemical compound, the feedthrough comprising an electrically conductive ferrule, an elongated electrically conductive feedthrough pin, and annular glass insulator supporting the electrically conductive feedthrough pin spaced from the feedthrough ferrule, comprising:
-
attaching the feedthrough ferrule of the feedthrough to a side wall of the housing to dispose the feedthrough pin extending through the side wall; and
coating the interior surface of the feedthrough insulator vulnerable to degradation upon contact with the reactive chemical compound with polyimide that forms a polyimide coating that tenaciously adheres to the vulnerable surfaces and is resistant to degradation by the reactive chemical compound. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method of protecting vulnerable surfaces of a feedthrough within a housing of an electrochemical cell of the type having a lithium anode, a cathode selected from the group consisting of silver vanadium oxide(SVO) cathode and a hybrid CFx/SVO cathode formed of SVO and carbon monofluoride (CFx), and a liquid organic type electrolyte that comprises a lithium salt in combination with an organic solvent, the feedthrough comprising an electrically conductive ferrule, an elongated electrically conductive feedthrough pin, and annular glass insulator supporting the electrically conductive feedthrough pin spaced from the feedthrough ferrule subject to degradation by the electrolyte or bridging by deposition of lithium across the glass insulator, comprising:
-
attaching the feedthrough ferrule of the feedthrough to a side wall of the housing to dispose the feedthrough pin extending through the side wall; and
coating the interior surface of the feedthrough glass insulator vulnerable to degradation upon contact with the reactive chemical compound with polyimide that forms a polyimide coating that tenaciously adheres to the vulnerable surfaces and is resistant to degradation by the reactive electrolyte and increases the distance that deposited lithium must extend to form an electrically conductive bridge between the feedthrough pin and ferrule. - View Dependent Claims (8, 9, 10, 11, 12)
-
-
13. An electrochemical cell comprising:
-
an anode having an anode current collector disposed operatively in respect thereof;
a cathode having a cathode current collector disposed operatively in respect thereof, the cathode being disposed operatively in respect of the anode, the anode and cathode being disposed within the housing;
a separator between the anode and cathode;
a reactive liquid electrolyte permeating the separator;
a metal housing enclosing the anode, cathode, separator and electrolyte having a housing side wall with an opening therethrough;
a feedthrough comprising an electrically conductive ferrule, an elongated electrically conductive feedthrough pin, and annular glass insulator supporting the electrically conductive feedthrough pin spaced from the feedthrough ferrule, the ferrule hermetically sealed into the opening in the side wall to dispose the feedthrough pin extending through the side wall electrically insulated from the housing and coupled to one of the anode and cathode; and
a polyimide coating resistant to degradation by the electrolyte over the interior surface of the feedthrough glass insulator - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
-
Specification