Thin-film batteries with soft and hard electrolyte layers and method
A method and apparatus for making thin-film batteries having composite multi-layered electrolytes with soft electrolyte between hard electrolyte covering the negative and/or positive electrode, and the resulting batteries. In some embodiments, foil-core cathode sheets each having a cathode material (e.g., LiCoO 2 ) covered by a hard electrolyte on both sides, and foil-core anode sheets having an anode material (e.g., lithium metal) covered by a hard electrolyte on both sides, are laminated using a soft (e.g., polymer gel) electrolyte sandwiched between alternating cathode and anode sheets. A hard glass-like electrolyte layer obtains a smooth hard positive-electrode lithium-metal layer upon charging, but when very thin, have randomly spaced pinholes/defects. When the hard layers are formed on both the positive and negative electrodes, one electrode's dendrite-short-causing defects on are not aligned with the other electrode's defects. The soft electrolyte layer both conducts ions across the gap between hard electrolyte layers and fills pinholes.
1. A method of forming a battery cell having a composite electrolyte structure comprising:
a) providing a positive electrode component;
b) providing a negative electrode component;
c) depositing a first electrolyte layer having randomly spaced defects therein on the negative electrode component;
d) depositing a second electrolyte layer having randomly spaced defects therein on a positive electrode component;
e) providing a third electrolyte material that comprises a polymer or a gel that is soft compared to the first and second electrolyte layers;
f) laminating the first electrolyte layer on the negative electrode to the second electrolyte layer on the positive electrode using the third soft electrolyte material to at least partially fill and fix the defects in at least one of the first and second electrolyte layers to form the composite electrolyte structure of the battery cell.
2. The method of claim 1 , further comprising laminating two or more battery cells together to form a laminated battery device.
3. The method of claim 1 , wherein the laminated battery device comprises a stack of two-sided anode current collectors and two-sided cathode current collectors that are connected in parallel.
4. The method of claim 1 , wherein the laminated battery device comprises a stack of two-sided anode current collectors and two-sided cathode current collectors that are connected in series.
5. The method of claim 1 , wherein the third electrolyte layer is an adhesive that provides a structural connection between the first and second electrolyte layers.
6. The method of claim 1 , wherein the positive electrode component comprises a current collector onto which is deposited a cathode material.
7. The method of claim 1 , wherein the negative electrode component comprises a current collector, and wherein a layer of lithium is formed as an active portion of the negative electrode component after assembly of the battery cell.
8. The method of claim 1 , wherein the first and second electrolyte layers are LiPON.
9. The method of claim 1 , wherein the third electrolyte layer is sticky.
10. The method of claim 8 , wherein the third electrolyte layer comprises polyvinylidene difluoride, propylene carbonate, and a lithium salt.
11. The method of claim 8 , wherein the third electrolyte layer comprises MEEP.
12. The method of claim 1 , wherein the cathode electrode component includes LiCoO 2 that is deposited on a positive electrode current-collector material, and the second electrolyte layer on the positive electrode component is a layer of LiPON that is deposited on the LiCoO 2 .
13. The method of claim 1 , wherein the negative electrode component includes a negative-electrode current collector made of a metal that does not readily alloy with lithium during a plating operation, and lithium metal is plated onto the negative-electrode current collector through the first electrolyte layer on the negative electrode component.
14. The method of claim 1 , wherein the third electrolyte layer comprises a polyphosphazene and a lithium salt.