Flexible thin printed battery and device and method of manufacturing same
View Patent ↗A flat, flexible electrochemical cell is provided. The within invention describes various aspects of the flat, flexible electrochemical cell. A printed anode is provided that obviates the need for a discrete anode current collector, thereby reducing the size of the battery. An advantageous electrolyte is provided that enables the use of a metallic cathode current collector, thereby improving the performance of the battery. Printable gelled electrolytes and separators are provided, enabling the construction of both co-facial and co-planar batteries. Cell contacts are provided that reduce the potential for electrolyte creepage in the flat, flexible electrochemical cells of the within invention.
1. A method for making an electrochemical battery cell comprising a printed negative electrode, the method comprising the steps:
a. preparing a zinc containing ink by mixing an aqueous solvent, a zinc powder, a binder soluble in the solvent, and a zinc compound soluble in the solvent and comprising a member selected from the group consisting of zinc chloride and zinc acetate, without substantially oxidizing the zinc powder;
b. printing the zinc containing ink onto a substrate to form a negative electrode;
c. preparing a positive electrode;
d. preparing an aqueous electrolyte;
e. combining the negative electrode, positive electrode and electrolyte in a container; and
f. sealing the container to form a sealed electrochemical battery cell.
2. The method according to claim 1 , wherein the electrolyte is an alkaline electrolyte.
3. The method according to claim 2 , wherein the zinc compound comprises zinc chloride.
4. The method according to claim 2 , wherein the binder comprises polyethylene oxide.
5. The method according to claim 1 , wherein the electrolyte is an acidic electrolyte.
6. The method according to claim 5 , wherein the zinc compound comprises zinc acetate.
7. The method according to claim 5 , wherein the binder comprises polyvinylpyrrolidone.
8. The method according to claim 7 , wherein the aqueous solvent comprises N-methylpyrrolidone.
9. The method according to claim 1 , wherein the cell comprises a separator comprising a paper.
10. The method according to claim 1 , wherein the cell comprises a separator comprising a gelled electrolyte.
11. The method according to claim 10 , wherein the electrolyte is an acidic electrolyte comprising a gelling agent and the gelling agent comprises a member selected from the group consisting of nonionic and anionic derivatives and natural guar gum, a polyethylene glycol based polymer, polyethylene oxide, and fumed silica.
12. The method according to claim 11 , wherein the separator is printed onto at least one of the negative and positive electrodes and comprises a polyethylene glycol based polymer, and fumed silica.
13. The method according to claim 1 , wherein the substrate is flexible and electrically non-conductive.
14. The method according to claim 1 , wherein the negative electrode is printed directly onto the substrate with no intervening current collector between the substrate and the ink.
15. The method according to claim 14 , wherein the electrodes and the separator are flexible and the container comprises a flexible pouch.