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 is positioned between the first and second anodes and adheres together the first and second anodes, and
wherein the release layer is non-electrically conductive.
2. A method, comprising:
providing a first anode;
providing a release layer disposed on the first anode, wherein the release layer has an adhesive affinity to the anode greater than its adhesive affinity to a substrate on which at least a portion of the anode was fabricated;
providing a second anode; and
laminating the first and second anodes together to form an assembly in which the release layer is positioned between the first and second anodes, and
wherein the release layer is non-electrically conductive.
3. A final electrochemical cell, comprising:
a first anode;
a second anode;
an electrolyte; and
a release layer positioned between the first and second anodes, wherein the release layer adheres together the first and second anodes, and
wherein the release layer comprises a polymeric material comprising poly(vinyl alcohol) that is greater than 80% hydrolyzed.
4. A final electrochemical cell as in claim 1 , wherein the release layer comprises a polymeric material.
5. A final electrochemical cell as in claim 1 , wherein the release layer has a thickness of between 0.01 and 10 microns.
6. A final electrochemical cell as in claim 1 , wherein the release layer has a thickness of 5 microns or less.
7. A final electrochemical cell as in claim 1 , wherein the release layer comprises a surfactant.
8. A final electrochemical cell as in claim 1 , wherein at least 80 wt % of the release layer is a non-UV curable material.
9. A final electrochemical cell as in claim 1 , wherein the first anode comprises a current collector and an electroactive material layer.
10. A final electrochemical cell as in claim 9 , wherein the current collector is positioned between the electroactive layer and the release layer.
11. A final electrochemical cell as in claim 10 , wherein the current collector is positioned immediately adjacent the release layer, and the electroactive material layer is positioned immediately adjacent the current collector.
12. A final electrochemical cell as in claim 9 , wherein the current collector has a thickness of 12 microns or less.
13. A final electrochemical cell as in claim 9 , wherein the current collector has a thickness of 3 microns or less.
14. A final electrochemical cell as in claim 9 , wherein the current collector has a thickness of 1 micron or less.
15. A final electrochemical cell as in claim 9 , wherein the current collector has a thickness of between 0.1-0.5 microns.
16. A final electrochemical cell as in claim 15 , wherein the release layer has a thickness of between 1-5 microns.
17. A final electrochemical cell as in claim 9 , wherein the electroactive material layer comprises lithium.
18. A final electrochemical cell as in claim 9 , wherein the electroactive material layer comprises lithium metal.
19. A final electrochemical cell as in claim 9 , wherein the electroactive material layer has a thickness of greater than 5 microns.
20. A final electrochemical cell as in claim 1 , wherein the electrochemical cell has applied to it, 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 98 Newtons per square cm.