Flat sealing of anode/separator assembly for use in capacitors

An anode/separator assembly for a capacitor, the assembly comprising:

• a) a pellet of anode active material having opposed first and second major face walls extending to and meeting with a surrounding sidewall;
• and
• b) a separator enclosing the pellet and comprising:
• i) a first sheet of separator material including a first central region contiguous with the first major face wall of the anode pellet and a first perimeter region folded into contact with the surrounding sidewall of the anode pellet;
• and
• ii) a second sheet of separator material including a second central region contiguous with the second major face wall of the anode pellet and a second perimeter region overlapping a portion or the first perimeter region of the first separator sheet at the anode pellet surrounding sidewall;
• and
• iii) wherein the first and second separator sheets are sealed to each other at a fused seam formed of the overlapping first and second perimeter regions against the anode pellet surrounding sidewall serving as a backing surface as the fused seam was formed.

A capacitor, which comprises:

• a) a casing comprising first and second casing members secured to each other;
• b) an anode comprising a pellet of anode active material and having opposed first and second major face walls extending to and meeting with a surrounding sidewall;
• c) a separator enclosing the anode pellet and comprising:
• i) a first sheet of separator material including a first central region contiguous with the first major face wall of the anode pellet and a first perimeter region folded into contact with the surrounding sidewall of the anode pellet;
• and
• ii) a second sheet of separator material including a second central region contiguous with the second major face wall of the anode pellet and a second perimeter region overlapping a portion of the first perimeter region of the first separator sheet at the surrounding sidewall;
• iii) wherein the first and second separator sheets are sealed to each other at a fused sea formed at the overlap of their first and second perimeter regions against the anode pellet surrounding sidewall serving as a backing surface as the fused seam was formed;
• d) a cathode comprising cathode active material supported on the interior surfaces of the casing members opposite the first and second major face walls of the anode pellet;
• and
• e) an electrolyte contacting the cathode and the anode.

A method for making an anode/separator assembly for a capacitor, the method comprising the steps of:

• a) providing an anode comprising a pellet of anode active material having opposed first and second major face walls extending to and meeting with a surrounding side wall;
• b) contacting the first major face wall of the anode pellet with a first central region of a first sheet of separator material;
• c) folding a first perimeter region of the first separator sheet into contact with the surrounding side wall of the anode pellet;
• d) contacting the second major face wall of the anode pellet with a second central region of a second sheet of separator material;
• e) contacting the second perimeter region of the second separator sheet with the first perimeter region of the first separator sheet to form an overlap between the first and second separator sheets at the anode pellet surrounding sidewall;
• and
• f) sealing the first and second separator sheets to each other at the overlap with the anode pellet surrounding sidewall serving as a backing surface to form a sea that is contiguous with a portion of the surrounding sidewall of the pellet.