Electrochemical actuator

• US 7,872,396 B2
• Filed: 07/26/2007
• Issued: 01/18/2011
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Cima, Michael J., Chiang, Yet-Ming, Chin, Timothy E.
• Primary Examiner(s): Budd; Mark
• Application Number:
  US11/881,830
• Publication Number:
  US 20080257718A1
• Time in Patent Office: 1,272 Days
• Field of Search: 310/311
• US Class Current: 310/311
• CPC Class Codes: F03G 7/005 Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/587 for inserting or intercalating light metals
• CPC Class Codes: H01M 50/409 Separators, membranes or diaphragms characterised by the material
• CPC Class Codes: H01M 6/30 Deferred-action cells
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides systems, devices, and related methods, involving electrochemical actuation. In some cases, application of a voltage or current to a system or device of the invention may generate a volumetric or dimensional change, which may produce mechanical work. For example, at least a portion of the system may be constructed and arranged to be displaced from a first orientation to a second orientation. Systems such as these may be useful in various applications, including pumps (e.g., infusion pumps) and drug delivery devices, for example.

Claims

1. An actuator system constructed and arranged to be displaced from a first orientation to a second orientation, comprising:

at least one electrochemical cell comprising a negative electrode and a positive electrode,

wherein one or both of the negative and positive electrodes is an actuator, and comprises a first portion and a second portion, and

wherein upon charge and/or discharge, a species is intercalated, de-intercalated, alloys with, oxidizes, reduces, or plates with the first portion to a different extent than the second portion, and experiences a resulting dimensional change relative to the second portion, thereby imparting to the actuator a differential strain between the first and second portions causing a displacement of at least a portion of the actuator,

which actuator displacement does mechanical work without the need to be coupled to a structure which does said work.

2. An actuator system of claim 1, wherein the first portion is in electrical communication with the second portion.

3. An actuator system of claim 1, wherein the species is an intercalating species.

4. An actuator system of claim 1, wherein the species is a proton.

5. An actuator system of claim 1, wherein the species is a plating species.

6. An actuator system of claim 1, wherein the first and second portions are formed of different materials.

7. An actuator system of claim 1, wherein the first and second portions are formed of substantially the same materials.

8. An actuator system of claim 1, wherein the first and second portions have different electrical potentials.

9. An actuator system of claim 1, wherein the first and second portions are exposed to the species to a different extent.

10. An actuator system of claim 1, further comprising a structure including at least one portion constructed and arranged to be displaced from a first orientation to a second orientation by the displacement of the actuator.

11. An actuator system of claim 1, wherein the species substantially intercalates, deintercalates, or alloys with the first portion but not with the second portion.

12. An actuator system of claim 1, wherein the first portion intercalates the species to a different extent than the second portion so as to impart a differential strain between the first and second portions.

13. An actuator system of claim 1, wherein the first portion alloys with the species to a different extent than the second portion so as to impart a differential strain between the first and second portions.

14. An actuator system of claim 1, wherein the first and second portions are conductive.

15. An actuator system of claim 1, wherein upon charge or discharge, the displacement of at least a portion of the actuator applies a force on a reservoir, causing volume displacement of a fluid from the reservoir.

16. An actuator system of claim 15, wherein the fluid contains a drug.

17. An actuator system of claim 16, wherein the drug is insulin.

18. An actuator system of claim 1, wherein the positive and/or negative electrode is in the shape of a strip, plate, sheet, cup, folded sheet, or strip.

19. An actuator system of claim 1, wherein the positive and/or negative electrode is nonplanar.

20. An actuator system of claim 1, wherein the positive and/or negative electrode is a plate or pellet.

21. An actuator system of claim 1, wherein the positive and/or negative electrode comprises at least one groove.

22. An actuator system of claim 1, wherein the positive and/or negative electrode has multiple “

legs”

or “

arms”

or branches.

23. An actuator system of claim 1, wherein the electrochemical cell is constructed and arranged to spontaneously discharge.

24. An actuator system of claim 1, wherein the actuator system is coupled to a structure which does mechanical work.

25. An actuator system of claim 1, wherein the actuator system is not coupled to a structure which does mechanical work.

26. An actuator system of claim 1, wherein the actuator displacement is generated by a volumetric or dimensional change of the actuator system that is positive.

27. An actuator system of claim 1, wherein the actuator displacement is generated by a volumetric or dimensional change of the actuator system that is zero.

28. An actuator system of claim 1, wherein the actuator displacement is generated by a volumetric or dimensional change of the actuator system that is negative.