Release system for electrochemical cells
Electrochemical cells, and more specifically, release systems for the fabrication of electrochemical cells are described. In particular, release layer arrangements, assemblies, methods and compositions that facilitate the fabrication of electrochemical cell components, such as electrodes, are presented. In some embodiments, methods of fabricating an electrode involve the use of a release layer to separate portions of the electrode from a carrier substrate on which the electrode was fabricated. For example, an intermediate electrode assembly may include, in sequence, an electroactive material layer, a current collector layer, a release layer, and a carrier substrate. The carrier substrate can facilitate handling of the electrode during fabrication and/or assembly, but may be released from the electrode prior to commercial use.
1. A final electrochemical cell comprising:
a first anode;
a second anode;
an electrolyte;
a cathode; and
a release layer having an adhesive affinity to at least one component of the electrochemical cell greater than its adhesive affinity to a substrate on which at least a portion of the electrochemical cell was fabricated, wherein the release layer comprises a polymeric material including pendant hydroxyl functional groups, and wherein the release layer is positioned between the first and second anodes and adheres together the first and second anodes.
2. A final electrochemical cell as in claim 1 , wherein the polymeric material is greater than 80% hydrolyzed.
3. A final electrochemical cell as in claim 1 , wherein the release layer comprises poly(vinyl alcohol).
4. A final electrochemical cell as in claim 1 , wherein the release layer has a thickness of between 0.01 and 10 microns.
5. A final electrochemical cell as in claim 1 , wherein the release layer has a thickness of about 5 microns or less.
6. A final electrochemical cell as in claim 1 , wherein the release layer comprises a surfactant.
7. A final electrochemical cell as in claim 1 , wherein at least 80 wt % of the release layer is a non-UV curable material.
8. A final electrochemical cell as in claim 1 , wherein the first anode comprises a current collector and an electroactive material layer.
9. A final electrochemical cell as in claim 8 , wherein the current collector is positioned between the electroactive layer and the release layer.
10. A final electrochemical cell as in claim 9 , wherein the current collector is positioned immediately adjacent the release layer, and the electroactive material layer is positioned immediately adjacent the current collector.
11. A final electrochemical cell as in claim 8 , wherein the current collector has a thickness of about 12 microns or less.
12. A final electrochemical cell as in claim 8 , wherein the current collector has a thickness of about 3 microns or less.
13. A final electrochemical cell as in claim 8 , wherein the current collector has a thickness of about 1 micron or less.
14. A final electrochemical cell as in claim 8 , wherein the current collector has a thickness of between 0.1-0.5 microns.
15. A final electrochemical cell as in claim 14 , wherein the release layer has a thickness of between 1-5 microns.
16. A final electrochemical cell as in claim 15 , wherein the release layer comprises poly(vinyl alcohol).
17. A final electrochemical cell as in claim 16 , wherein the poly(vinyl alcohol) is greater than 80% hydrolyzed.
18. A final electrochemical cell as in claim 8 , wherein the electroactive material layer comprises lithium.
19. A final electrochemical cell as in claim 8 , wherein the electroactive material layer comprises lithium metal.
20. A final electrochemical cell as in claim 8 , wherein the electroactive material layer has a thickness of greater than about 5 microns.
21. A final electrochemical cell as in claim 1 , wherein the electrochemical cell is constructed and arranged to apply, during at least one period of time during charge and/or discharge of the electrochemical cell, an anisotropic force with a component normal to a surface of the electrode, wherein the component defines a pressure of at least about 98 Newtons per square cm, and wherein the release layer is configured to withstand the application of force during cycling of the cell.
22. A final electrochemical cell as in claim 1 , wherein the polymeric material is greater than 90% hydrolyzed.
23. A final electrochemical cell as in claim 1 , wherein the polymeric material comprises a vinyl acetate-vinyl alcohol copolymer.