Thin printable electrochemical cell and methods of making the same
A thin printed flexible electrochemical cell, and its method of manufacture, using a “picture frame” structure sealed, for example, with a high moisture and oxygen barrier polymer film and featuring, for example, a printed cathode deposited on an optional, highly conductive carbon printed cathode collector with a printed or a foil strip anode placed adjacent to the cathode. A viscous or gelled electrolyte is dispensed and/or printed in the cell, and a top laminate can then be sealed onto the picture frame. Such a construction could allow the entire cell to be made on a printing press, for example, as well as gives the opportunity to integrate the battery directly with an electronic application, for example.
1. A flat electrochemical cell for generating an electrical current, comprising:
a first substrate layer comprising a plurality of laminated layers including a first oxide barrier layer having a gas transmission rate that permits gas to escape through said plurality of laminated layers of the first substrate layer;
a second substrate layer;
a cathode layer provided on said first substrate layer or said second substrate layer;
an anode layer provided on the same of said first substrate layer and said second substrate layer as said cathode layer, said anode layer and said cathode layer thereby being arranged substantially co-planar;
a liquid electrolyte in contact with said cathode layer and also in contact with said anode layer; and
said first substrate layer being connected to said second substrate layer to form an inner space containing said electrolyte, wherein
at least one of said anode layer and said cathode layer is formed of a cured or dried ink.
2. The electrochemical cell of claim 1 , further comprising a cathode current collector disposed between said cathode layer and the substrate on which the cathode layer is provided.
3. The electrochemical cell of claim 2 , further comprising an anode current collector disposed between said anode layer and the substrate on which the anode layer is provided.
4. The electrochemical cell of claim 1 , said second substrate layer comprising a plurality of laminated layers including a second oxide barrier layer having a gas transmission rate that permits gas to escape through said plurality of laminated layers of the second substrate layer.
5. The electrochemical cell of claim 1 , said electrolyte being a gel electrolyte.
6. The electrochemical cell of claim 1 , further comprising a soak up separator soaked with said electrolyte and in contact with both said anode layer and said cathode layer in said inner space.
7. The electrochemical cell of claim 1 , said first oxide barrier layer being effective to prevent substantial moisture transmission therethrough.
8. The electrochemical cell of claim 1 , said first substrate layer and second substrate layer being connected via a frame disposed therebetween.
9. The electrochemical cell of claim 8 , said frame comprising a cured or dried adhesive ink.
10. The electrochemical cell of claim 1 , said cathode layer being printed from an aqueous composition comprising about 20-60% manganese dioxide, about 2-25% graphite and about 0.5%-15% of an aqueous solution of comprising about 20-60% polyvinylpyrrolidone and about 0.1-20% of distilled water to provide a dry lay down weight of about 0.03-0.25 grams per square inch.
11. The electrochemical cell of claim 2 , said cathode current collector comprising a cured or dried ink printed on said substrate, said cathode comprising a cured or dried ink printed on said cathode current collector.
12. The electrochemical cell of claim 11 , said cathode collector layer being printed from a different ink than said cathode layer.
13. The electrochemical cell of claim 1 , said first substrate layer further comprising a first heat sealing layer.
14. The electrochemical cell of claim 13 , said second substrate layer further comprising a second heat sealing layer.
15. The electrochemical cell of claim 1 , each of said anode layer and said cathode layer being formed of a cured or dried ink.
16. The electrochemical cell of claim 1 , said cathode layer being printed from an aqueous composition comprising manganese dioxide, graphite and hydroxyl-ethyl cellulose.
17. The electrochemical cell of claim 1 , said oxide barrier layer being selected such that its barrier properties are configured to provide a desired gas transmission rate corresponding to a specific application or environment during use.
18. The electrochemical cell of claim 17 , said barrier properties being configured to provide a desired gas transmission rate corresponding to a hot, dry environment such that said barrier layer exhibits a low transmission rate to prevent substantial moisture loss from said cell.
19. The electrochemical cell of claim 13 , said first substrate layer further comprising a first structural layer whose thickness is selected such that the first substrate layer's material properties are configured to provide a desired structural strength corresponding to a specific application or environment during use.
20. The electrochemical cell of claim 1 , said cell having a non-rectangular shape.
21. A battery comprising a plurality of electrochemical cells according to claim 1 .