Microscopic batteries for MEMS systems

• US 7,462,419 B2
• Filed: 11/05/2004
• Issued: 12/09/2008
• Est. Priority Date: 03/10/1998
• Status: Expired due to Fees

• Current Assignee: Bipolar Technologies Corporation
• Original Assignee: Bipolar Technologies Corporation
• Inventors: Harb, John N., LaFollette, Rodney M., Salmon, Linton G.
• Primary Examiner(s): Alejandro; Raymond
• Application Number:
  US10/982,270
• Publication Number:
  US 20050093380A1
• Time in Patent Office: 1,495 Days
• Field of Search: 429/122, 429/121, 429/304, 429/236, 429/234, 429/124, 429/157, 429/208, 429/7, 429/127, 429/162, 429/185, 429/192, 429/193, 429/194, 429/218, 429/247, 429/248, 296/231, 296/235, 359/265, 359/275, 204/421
• US Class Current: 429/122
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/287 Small-sized flat cells or batteries for portable equipment H01M10/283 and H01M10/286 take precedence
• CPC Class Codes: H01M 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/342 Gastight lead accumulators H01M10/121 takes precedence
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 50/11 having a chip structure, e.g. micro-sized batteries integrated on chips
• CPC Class Codes: H01M 6/40 Printed batteries , e.g. thin film batteries
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/49115 including coating or impregnating

Abstract

Microscopic batteries, integratable or integrated with and integrated circuit, including a MEMS microcircuit, and methods of microfabrication of such microscopic batteries are disclosed.

Claims

1. A microfabricated battery comprising a system for internal storage of electricity comprising reactants, the microfabricated battery having a volumetric size which is microscopic including a micrometer footprint substantially less than 20 cm² and congruent with a microelectronic circuit accommodating integration with the circuit to provide long term stored power and to materially limit power losses, the microfabricated battery comprising a body of material having a first microfabricated electrode of chemically reactant material, a second microfabricated electrode spaced from the first electrode and a microscopic amount of internal ion-transmitting electrolyte which restricts electronic current flow and accommodates reactions at the electrodes contained within an internal microfabricated space in the body accessible to both electrodes.

2. The microfabricated battery according to claim 1 wherein the microfabricated battery is rechargeable.

3. The microfabricated battery according to claim 1 wherein the microfabricated battery is primary.

4. The microfabricated battery according to claim 1 further comprising an autonomous sensor system integrated with the microfabricated battery.

5. The microfabricated battery according to claim 4 wherein the autonomous sensor system senses conditions, analyzes data, and issues radio frequency signals.

6. The microfabricated battery according to claim 1 wherein at least one of the electrodes comprises a microfabricated film of conductive material.

7. The microfabricated battery according to claim 1 wherein the electrodes are held apart by a separator comprising the electrolyte.

8. The microfabricated battery according to claim 1 wherein the electrodes are carried on a rigid dielectric substrate.

9. The microfabricated battery according to claim 1 wherein the electrodes are carried on a flexible sheet.

10. The microfabricated battery according to claim 1 wherein the electrodes are created by metallic deposition, thin layer lithographic patterning and etching.

11. The microfabricated battery according to claim 1 wherein the electrodes comprise an etched profile obtained by removing sacrificial material.

12. The microfabricated battery according to claim 1 wherein the second microfabricated electrode is comprised of a chemical reactant material.

13. The microfabricated battery according to claim 7 wherein the separator is comprised of polymeric material.

14. The microfabricated battery according to claim 7 wherein the separator is comprised of a dielectric material.

15. The microfabricated battery according to claim 7 wherein the separator comprises both solid and liquid materials.

16. A method comprising the acts of:

fabricating a microfabricated electrical energy storage battery comprised of reactant microfabricated electrodes by which an electrical charge is chemically transferred and having a microscopic footprint substantially less than 20 cm² which is size-congruent and electronically compatible with a microelectromechanical system;

integrating the microfabricated battery into the microelectromechanical system as an integrated internal source of electrical power.

17. A method comprising the acts of:

fabricating a microfabricated electrical energy storage battery comprised of chemical reactant microfabricated electrodes and having a microscopic footprint substantially less than 20 cm ² which is size-congruent, material-compatible and electronically suitable to be integrated into microcircuitry;

integrating the microfabricated battery with the microcircuitry as a long term internally-derived source of electrical power.

18. The microfabricated battery according to claim 17 wherein the microcircuitry is selected from the group consisting of a microelectromechanical system and a non-microelectromechanical microcircuit.

19. A method comprising the acts of:

fabricating a microfabricated electrical energy storage battery comprising a microscopic footprint substantially less than 20 cm ² which is size-congruent material-compatible and electronically-suitable to be integrated as a power source into a microfabricated circuit;

integrating the microfabricated battery into the microfabricated circuit as a fully integrated internally derived source of electrical power.

20. A method of making a microfabricated battery for internal storage of electricity comprising the acts of:

forming spaced film microfabricated electrode layers of reactant materials upon non-conducting material, each layer having a microfabricated volume comprising a footprint substantially less than 20 cm²;

etching away sacrificial portions of at least one film microfabricated electrode layer of reactant material;

interposing reaction-accommodating electrolyte between the remaining microfabricated electrode layers of reactant material within a housing so that the electrode layers serve as internal only sources of reactants.

21. The method according to claim 20 further comprising the act of interposing a microfabricated separator in communication with the electrolyte between the microfabricated electrode layers.

22. The method according to claim 21 wherein the microfabricated separator is etched to provide a cavity for the electrolyte.

23. The method according to claim 20 further comprising the act of interposing a non-conductive microfabricated polymeric separator in communication with the electrolyte between the microfabricated electrode layers.

24. A conformable microfabricated battery comprising microfabricated volume and an internal only source of electricity having a first microfabricated electrode of reactant material in the form of a microscopic wire, reaction-accommodating electrolyte concentrically disposed around the microscopic wire and a second hollow tubular microscopic electrode of reactant material concentrically surrounding the electrolyte, the surface area of which is microscopic and substantially less than 20 cm².

25. The conformable microfabricated battery according to claim 24 wherein the electrolyte is aqueous.

26. The conformable microfabricated battery according to claim 25 wherein the aqueous electrolyte is disposed in a porous material.

27. The conformable microfabricated battery according to claim 24 wherein the electrolyte is solid.

28. A rechargeable microfabricated battery comprising an internally operated source of electricity comprising internal only reactants in the nature of first and second spaced microfabricated electrodes, each being microfabricated to a microscopic volume and comprising a microfabricated footprint substantially less than 20 cm² and a microscopic amount of aqueous reaction-accommodating electrolyte disposed in a microfabricated cavity between the reactant microfabricated electrodes.

29. A method of making a microfabricated battery comprising an internally operated source of electricity comprising internal only reactants, the method comprising the seriatim acts of depositing as microfabricated film a microscopic internal reactant in the nature of a first microfabricated electrode, a spacer and a microscopic internal reactant in the nature of a second microfabricated electrode comprising a footprint substantially smaller than 20 cm², etching a part of the spacer to create a microfabricated cavity which accesses to both electrodes and filling the microfabricated cavity with aqueous reaction-accommodating electrolyte through a passageway in one of the thin films.

30. The method according to claim 29 wherein the filling act is through a passageway in one of the microfabricated electrodes.

31. A microfabricated battery comprising at least one cell comprising spaced microfabricated reactant electrodes and a microscopic amount of reaction-accommodating electrolyte disposed between the reactant microfabricated electrodes, the battery providing specific power within the range of 10⁻

0.4 to 10^1.6 KW/kg and specific energy within the range of 10^1.1 to 10^2.1 kJ/kg.