Safety shutdown separators
AssigneeOptodot Corporation
InventorsSteven Allen Carlson, Ifenna Kingsley Anakor, Greg Robert Farrell
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Abstract
The present invention pertains to electrochemical cells which comprise (a) an anode; (b) a cathode; (c) a solid porous separator, such as a polyolefin, xerogel, or inorganic oxide separator; and (d) a nonaqueous electrolyte, wherein the separator comprises a porous membrane having a microporous coating comprising polymer particles which have not coalesced to form a continuous film. This microporous coating on the separator acts as a safety shutdown layer that rapidly increases the internal resistivity and shuts the cell down upon heating to an elevated temperature, such as 110° C. Also provided are methods for increasing the safety of an electrochemical cell by utilizing such separators with a safety shutdown layer.
Claims15
An electrochemical cell comprising:
- (i) an anode;
- (ii) a cathode;
- (iii) a solid porous separator;
- and
- (iv) a nonaqueous electrolyte, wherein said separator and said electrolyte are interposed between said anode and said cathode;
- and wherein said separator comprises an inorganic oxide separator layer having a microporous coating on one side of said separator layer, wherein said microporous coating comprises styrenated acrylic polymer particles having a diameter of between 100 and 150 nm.
An electrochemical cell comprising:
- (i) an anode;
- (ii) a cathode;
- (iii) a solid porous separator;
- and
- (iv) a nonaqueous electrolyte, wherein said separator and said electrolyte are interposed between said anode and said cathode;
- and wherein said separator comprises an inorganic oxide separator layer having a microporous coating on one side of said separator layer, wherein said microporous coating comprises styrenated acrylic polymer particles having a diameter of between 100 and 150 nm wherein said separator shuts down by increasing the Gurley air porosity of said separator to above 60 minutes/100 cm3 at a temperature at least 40° C. below the temperature at which said separator shuts down when heated in air with none of said electrolyte present.
Dependencies are inferred from the claim text.