Electrochemical actuator

• US 8,093,781 B2
• Filed: 12/03/2010
• Issued: 01/10/2012
• 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:
  US12/960,224
• Publication Number:
  US 20110098643A1
• Time in Patent Office: 403 Days
• Field of Search: None
• 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. A device for delivering a fluid, comprising:

a reservoir configured to contain a fluid; and

an electrochemical actuator including an electrode having a first portion and a second portion, the first portion configured to allow intercalation of a species to a different extent than the second portion, the electrode configured to deflect upon charge and/or discharge of the electrochemical actuator, the deflection of the electrode being operative to cause fluid to be delivered from the reservoir.

2. The device of claim 1, wherein the reservoir comprises a deformable bladder, and the electrochemical actuator is in direct contact with the deformable bladder.

3. The device of claim 1, further comprising:

a transfer structure positioned between the reservoir and the electrochemical actuator, the transfer structure being adapted to transfer mechanical work produced by the electrochemical actuator to the reservoir.

4. The device of claim 1, wherein intercalation of the species to the first portion to a different extent than the second portion imparts a differential strain between the first portion and the second portion, thereby causing deflection of the electrode.

5. The device of claim 1, wherein the first portion is configured to impart a mechanical constraint on the second portion, thereby causing deflection of the electrode.

6. The device of claim 1, wherein the device is configured to deliver greater than 1 mL of a fluid from the reservoir.

7. A device for delivering a fluid, comprising:

a reservoir configured to contain a fluid; and

an electrochemical actuator including a bimorph electrode, the bimorph electrode having a first portion and a second portion, the first portion configured to allow intercalation of a species to a different extent than the second portion, the bimorph electrode configured to change volume or position upon charge and/or discharge of the electrochemical actuator, the change in volume or position of the electrochemical actuator being operative to cause fluid to be delivered from the fluid reservoir.

8. The device of claim 7, wherein the first portion and the second portion are formed of different materials.

9. The device of claim 8, wherein one of the first portion and the second portion comprises a dimensionally-active material.

10. The device of claim 7, wherein intercalation of the species to the first portion to a different extent than the second portion imparts a differential strain between the first portion and the second portion, thereby causing deflection of the electrode.

11. The device of claim 7, further comprising:

a housing suited for removably associating the reservoir with the body of a patient, the actuator being disposed within the housing and having a first end of the actuator anchored to the housing and a second end of the actuator unconstrained, and oriented so that when the actuator is actuated, the second end is displaced toward the reservoir and exerts a force on the reservoir such that fluid contained in the reservoir is delivered therefrom.

12. The device of claim 7, further comprising:

an electrical circuit electrically coupled to the bimorph electrode so as to allow the electrochemical actuator to discharge therethrough.

13. The device of claim 7, further comprising:

an electrical circuit electrically coupled to the bimorph electrode so as to allow the electrochemical actuator to discharge therethrough, the electrical circuit including only fixed resistive elements.

14. A device for delivering a fluid to a patient, comprising:

a fluid reservoir;

a housing suited for removably associating the fluid reservoir with the body of the patient; and

an electrochemical cell including a negative electrode, a positive electrode, and a species formulated to intercalate, de-intercalate, alloy with, oxidize, reduce, or plate with a first portion of the electrochemical cell to an extent different than a second portion of the electrochemical cell, thereby imparting a differential strain between the first and second portions and causing a displacement of at least a portion of the electrochemical cell, the displacement being operative to cause fluid to be delivered from the fluid reservoir.

15. The actuator device of claim 14, wherein charging and/or discharging of the electrochemical cell produces the differential strain.

16. The actuator device of claim 14, wherein the species is an intercalating species.

17. The device of claim 14, further comprising:

an electrical circuit electrically coupled to the negative electrode and the positive electrode so as to allow the electrochemical cell to discharge therethrough.

18. The device of claim 14, further comprising:

an electrical circuit electrically coupled to the negative electrode and the positive electrode so as to allow the electrochemical cell to discharge therethrough, the electrical circuit including only fixed resistive elements.

19. The device of claim 14, wherein the device is configured to deliver greater than 1 mL of the therapeutic from the fluid reservoir.

20. The device of claim 14, wherein the device is configured to deliver greater than 5 mL of the therapeutic from the fluid reservoir.