Electrochemical actuator

• US 8,247,946 B2
• Filed: 08/20/2010
• Issued: 08/21/2012
• Est. Priority Date: 06/14/2004
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Chiang, Yet-Ming, Cima, Michael J., Chin, Timothy E.
• Primary Examiner(s): Budd, Mark
• Application Number:
  US12/860,771
• Publication Number:
  US 20110042204A1
• Time in Patent Office: 732 Days
• Field of Search: 310/311, 310/328
• 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 10/052 Li-accumulators
• 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, comprising:

an electrochemical cell including a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is an actuator, the negative electrode and the positive electrode each being formed with a metallic material,

the actuator configured to be displaced from a first orientation to a second orientation, the actuator including a first portion and a second portion, and the first portion and the second portion each arranged such that the actuator has at least a two-fold symmetry when the actuator is in its second orientation when viewed normal to a surface of the actuator.

2. The actuator system of claim 1, wherein the actuator has three-fold symmetry when viewed normal to a surface of the actuator.

3. The actuator system of claim 1, wherein the actuator has four-fold symmetry when viewed normal to a surface of the actuator.

4. The actuator system of claim 1, further comprising:

a species formulated to intercalate, de-intercalate, alloy with, oxidize, reduce, or plate with the first portion of the actuator to an extent different than the second portion of the actuator, thereby imparting a differential strain between the first and second portions and causing a displacement of at least a portion of the actuator.

5. The actuator system of claim 4, wherein the species is formulated to intercalate with the first portion of the actuator to an extent different than the second portion of the actuator, the electrochemical cell has an initially charged state, and the species intercalates with the positive electrode as the electrochemical cell is allowed to discharge from its initially charged state.

6. The actuator system of claim 4, wherein the actuator is substantially rectangular and the displacement occurs along an axis that is parallel to an edge of the actuator.

7. The actuator system of claim 4, wherein the actuator is substantially circular and the displacement occurs along axes having three-fold symmetry when viewed normal to the surface of the actuator.

15. The actuator system of claim 1, wherein the first material is a metallic material and the second material is a metallic material.

8. An actuator system, comprising:

an electrochemical cell including a negative electrode and a positive electrode, at least one of the negative electrode and the positive electrode is an actuator, the actuator configured to be displaced from a first orientation to a second orientation, the actuator including a first portion and a second portion, the first portion and the second portion being arranged such that the actuator has at least a two-fold symmetry when the actuator is in its second orientation when viewed normal to a surface of the actuator,

at least a portion of the negative electrode is formed with a material formulated to at least one of intercalate, de-intercalate, alloy with, oxidize, reduce, or plate with the positive electrode such that a differential strain is imparted to the positive electrode.

9. The actuator system of claim 8, wherein the actuator has three-fold symmetry when viewed normal to a surface of the actuator.

10. The actuator system of claim 8, wherein the actuator has four-fold symmetry when viewed normal to a surface of the actuator.

11. The actuator system of claim 8, wherein the negative electrode and the positive electrode are mechanically coupled such that the differential strain imparted on the positive electrode causes a displacement of at least a portion of the actuator.

12. The actuator system of claim 11, wherein the electrochemical cell has an initially charged state, at least a portion of the negative electrode intercalates with the positive electrode as the electrochemical cell is allowed to discharge from its initially charged state.

13. The actuator system of claim 11, wherein the actuator is substantially rectangular and the displacement occurs about an axis that is parallel to an edge of the actuator.

14. The actuator system of claim 11, wherein the actuator is substantially circular and the displacement occurs along axes having three-fold symmetry when viewed normal to the surface of the actuator.

16. An actuator system, comprising:

an electrochemical cell including a negative electrode and a positive electrode, at least a portion of the negative electrode is formed with a material formulated to at least one of intercalate, de-intercalate, alloy with, oxidize, reduce, or plate with the positive electrode such that a differential strain is imparted to the positive electrode,

the electrodes being mechanically coupled such that differential strain produces a displacement of at least a portion of the electrochemical cell upon charging or discharging of the electrochemical cell, the displacement of the electrochemical cell from a first orientation to a second orientation having at least a two-fold symmetry when the electrochemical cell is in its second orientation when viewed normal to a surface of the actuator.

17. The actuator system of claim 16, wherein the positive electrode includes a metallic material.

18. The actuator system of claim 17, wherein the positive electrode includes a metallic material.

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

an electrochemical cell including a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is an actuator, the actuator including a first portion and a second portion, and the first and second portions arranged such that the electrode has three-fold symmetry when viewed normal to a surface of the actuator.

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

an electrochemical cell including a negative electrode and a positive electrode, wherein at least one of the negative electrode and the positive electrode is an actuator, the actuator including a first portion and a second portion, and the first and second portions arranged such that the electrode has at least a two-fold symmetry when viewed normal to a surface of the actuator; and

a species formulated to intercalate, de-intercalate, alloy with, oxidize, reduce, or plate with the first portion of the actuator to an extent different than the second portion of the actuator, thereby imparting a differential strain between the first and second portions and causing a displacement of at least a portion of the actuator, wherein the actuator is substantially circular and the displacement occurs along axes having three-fold symmetry when viewed normal to the surface of the actuator.