Electroactive polymer thermal electric generators

• US 6,628,040 B2
• Filed: 02/23/2001
• Issued: 09/30/2003
• Est. Priority Date: 02/23/2000
• Status: Expired due to Term

• Current Assignee: SRI International, Inc.
• Original Assignee: SRI International, Inc.
• Inventors: Pelrine, Ronald E., Kornbluh, Roy D., Eckerle, Joseph Stephen, Pei, Qibing
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US09/792,431
• Publication Number:
  US 20010032663A1
• Time in Patent Office: 949 Days
• Field of Search: 310/309, 310/339, 310/800, 310/306, 310/307
• US Class Current: 310/307
• CPC Class Codes: F02G 1/043 the engine being operated by expansion and contraction of a mass of working gas which is heated and cooled in one of a plurality of constantly communicating expansible chambers, e.g. Stirling cycle type engines
• CPC Class Codes: F02G 2243/52 acoustic
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 35/00 Piston pumps specially adapted for elastic fluids and characterised by the driving means to their working members, or by combination with, or adaptation to, specific driving engines or motors, not otherwise provided for
• CPC Class Codes: F04B 35/045 using solenoids
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F05C 2225/08 Thermoplastics
• CPC Class Codes: F25B 9/14 characterised by the cycle used, e.g. Stirling cycle
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H10N 30/308 Membrane type
• CPC Class Codes: Y10S 310/80 Piezoelectric polymers, e.g. PVDF

Abstract

This disclosed generators include one or more transducers that use electroactive polymer films to convert thermally generated mechanical energy to electrical energy. The generators may include one or more transmission mechanisms that convert a portion of thermal energy generated from a heat source such as internal combustion, external combustion, solar energy, geothermal energy or waste heat, to mechanical energy that is used to drive the one or more transducers located in the generator. The energy received by the transducers may be converted to electrical energy by the transducers in conjunction with conditioning electronics located within the generator. One embodiment of the present invention provides an energy conversion device with two chambers each chamber including a diaphragm transducer that may convert thermal energy to electricity using a thermodynamic cycle such as a Stirling gas cycle. The thermodynamic cycle of the energy conversion device may be reversed to provide cooling to an external device such as a semiconductor device.

Claims

1. A generator for converting thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer wherein the polymer has a maximum elastic area strain of at least 10 percent;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers; and

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer.

2. The generator of claim 1, wherein the one or more transmission mechanisms transfers a portion of the thermal energy via a mechanical linkage.

3. The generator of claim 1, wherein the portion of the thermal energy is converted to mechanical energy via a gas expansion.

4. The generator of claim 3, wherein the gas comprises one of helium, nitrogen, carbon dioxide, air, water, hydrocarbons, and refrigerants.

5. The generator of claim 1, wherein the one or more transmission mechanisms comprises a hydraulic fluid.

6. The generator of claim 5, wherein the hydraulic fluid is a boilable liquid.

7. The generator of claim 1, wherein the one or more transmission mechanisms comprises a heat exchange mechanism.

8. The generator of claim 7, wherein the heat exchange mechanism transfers thermal energy via heat conduction, heat convection, radiation heat transfer or combinations thereof.

9. The generator of claim 1, further comprising:

a combustion chamber for combustion of a fuel.

10. The generator of claim 9, wherein said fuel comprises one of a liquid fuel, a gaseous fuel, a gel fuel and a solid fuel.

11. The generator of claim 9, wherein the fuel comprises a material selected from the group consisting essentially of propane, butane, natural gas, hydrogen, kerosene, and gasoline, jet fuel, diesel, coal-derived fuels, biomass and other hydrocarbon fuels.

12. The generator of claim 9, further comprising:

at least one fuel inlet for injecting the fuel into said combustion chamber and at least one exhaust outlet for ejecting a combustion product gas mixture from said combustion chamber.

13. The generator of claim 9, further comprising:

a storage chamber for storing the fuel.

14. The generator of claim 13, further comprising:

a pump designed or configured to move the fuel from the storage chamber to the combustion chamber.

15. The generator of claim 14, wherein the pump is designed or configured to move an oxidizer to the combustion chamber.

16. The generator of claim 14, wherein the pump includes an electroactive polymer transducer.

17. The generator of claim 9, further comprising:

an ignition device for initiating combustion in said combustion chamber.

18. The generator of claim 9, wherein a portion of a surface bounding the combustion chamber is the polymer.

19. The generator of claim 18, wherein the combustion of the fuel results in a gas expansion, said gas expansion produces the deflection of the polymer portion of the surface bounding the combustion chamber.

20. The generator of claim 18, wherein the polymer portion of the surface bounding the combustion chamber expands to form one of a balloon-like shape a hemispherical shape, a cylinder shape, or a half-cylinder shape.

21. The generator of claim 9, wherein a portion of a surface bounding the combustion chamber is a piston.

22. The generator of claim 21, wherein the combustion of the fuel moves the piston to generate mechanical energy.

23. The generator of claim 1, further comprising:

a housing enclosing the one or more transducers, the conditioning electronics and the one or more transmission mechanisms.

24. The generator of claim 1, wherein the conditioning electronics are designed or configured to perform one or more of the following functions:

voltage step-up, voltage step-down and charge control.

25. The generator of claim 24, wherein charge is added to polymer or removed from the polymer using the charge control.

26. The generator of claim 1, further comprising:

an electrical interface designed or configured to output the electrical energy.

27. The generator of claim 1, further comprising:

one or more batteries designed or configured to store electrical energy removed from the one or more transducers or to increase the charge of the polymer.

28. The generator of claim 1, wherein the total electrical energy removed from the one or more transducers is greater than the total electrical energy added to the one or more transducers and wherein electrical energy is output from said generator.

29. The generator of claim 1, wherein the polymer comprises a material selected from the group consisting of a silicone elastomer, an acrylic elastomer, a polyurethane, a copolymer comprising PVDF, and combinations thereof.

30. The generator of claim 1, further comprising:

an insulation barrier designed or configured to minimize heat transfer between a first portion of the generator and a second portion of the generator.

31. The generator of claim 1, further comprising:

one or more support structures designed or configured to attach to said one or more transducers.

32. The generator of claim 1, further comprising:

one or more sensors connected to said generator.

33. The generator of claim 32, wherein at least one of the one or more sensors is

designed or configured to monitor a temperature or to monitor a pressure.

34. The generator of claim 32, wherein at least one of the one or more sensors is

the designed or configured to monitor at least one of the following quantities:

the deflection in the portion of the polymer, a voltage in the portion of the polymer or a

charge in the portion of the polymer.

35. The generator of claim 1, wherein the polymer comprises a first portion and a second portion arranged in a manner which causes a change in electric field in response to a deflection applied to at least one of said first portion and said second portion.

36. The generator of claim 1, further comprising:

a logic device.

37. The generator of claim 36, wherein the logic device is a microprocessor or a microcontroller.

38. The generator of claim 36, wherein the logic device is designed or configured to control an addition of charge, a deletion of charge or a combination thereof on said polymer.

39. The generator of claim 1, further comprising:

an insulation layer attached to the polymer wherein the insulation layer is designed or configured to reduce heat transfer to the polymer.

40. The generator of claim 39, wherein the insulation layer comprises at least one of a plurality of passive polymer layers, compliant inorganic materials and wetting liquids.

41. The generator of claim 1, wherein the thermal energy received by the one or more transmission mechanisms is solar energy, geothermal energy or excess energy from an engine block.

42. The generator of claim 1, wherein the polymer includes pre-strain.

43. The generator of claim 1, wherein the polymer has an elastic modulus below about 100 MPa.

44. The generator of claim 1, wherein the polymer comprises a multilayer structure.

45. The generator of claim 44, wherein the multilayer structure comprises a thermal shield layer.

46. The generator of claim 44, wherein the multilayer structure comprises a buffer layer.

47. The generator of claim 44, wherein the multilayer structure comprises two or more layers of electroactive polymers.

102. The generator of claim 1, further comprising:

step-down circuitry designed or configured to receive an input signal with an input voltage level and output an output signal with an output voltage level wherein the output voltage level is lower than the input voltage level.

103. The generator of claim 102, wherein said input sign ail is received from the charge control circuitry.

104. The generator of claim 102, further comprising:

an electrical output interface designed or configured to output the output signal.

105. The generator of claim 104, wherein the electrical output interface is connected to a battery.

106. The generator of claim 102, wherein the output voltage level is between about 3 Volts and about 400 Volts.

107. The generator of claim 102, further comprising:

one or more power conversion circuitry units.

108. The generator of claim 107, further comprising;

one or more capacitors designed or configured to reduce a voltage level of a signal received by said one or more power conversion circuitry units.

109. The generator of claim 1, further comprising:

step up circuitry designed or configured to receive an input signal with an input voltage level and output an output signal with an output voltage level wherein the input voltage level is lower than the output voltage level.

110. The generator of claim 109, wherein the output signal is received by the charge control circuitry.

111. The generator of claim 110, further comprising:

an electrical input interface designed or configured to receive an input signal.

112. The generator of claim 111, wherein the electrical input interface is connected to a battery.

113. The generator of claim 112, wherein a voltage of said battery is between about 1.5 Volts and about 48 Volts.

114. The generator of claim 109, further comprising:

a transformer.

115. The generator of claim 114, further comprising:

a transformer driver circuit for controlling said transformer.

116. The generator of claim 109, further comprising:

one or more sensor monitoring circuits.

117. The generator of claim 116, wherein at least one of the sensor monitoring circuits is designed or configured to monitor at least one of a temperature, a pressure, the deflection of the polymer, a charge on the polymer or a voltage on the polymer.

118. The generator of claim 116, further comprising:

a sensor output interface.

48. An electroactive polymer energy conversion device for converting between thermal energy and electrical energy, the energy conversion device comprising:

a) two or more transducers, each transducer comprising;

i) at least two electrodes; and

ii) a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer;

b) two chambers enclosing a volume of a working fluid distributed between said chambers, the two chambers comprising;

i) a first chamber, said first chamber comprising;

a first transducer;

a first portion of the working fluid enclosed by said first chamber;

ii) a second chamber, said second chamber comprising;

a second transducer;

a second portion of the working fluid enclosed by said second chamber;

c) conditioning electronics connected to the at least two electrodes in each transducer and designed or configured to apply a charge to said transducers; and

d) one or more transmission mechanisms designed or configured to receive thermal energy.

49. The energy conversion device of claim 48, further comprising:

a flow conduit designed or configured to allow the working fluid to flow between the first chamber and the second chamber.

50. The energy conversion device of claim 48, wherein thermal energy is added or removed from a working fluid flowing in said flow conduit.

51. The energy conversion device of claim 48, further comprising:

an insulation barrier designed or configured to minimize heat transfer between said first chamber and said second chamber.

52. The energy conversion device of claim 48, wherein the conditioning electronics remove electrical energy from at least one of the said transducers.

53. The energy conversion device of claim 48, further comprising:

an electrical interface designed or configured to output the electrical energy.

54. The energy conversion device of claim 48, further comprising:

one or more batteries designed or configured to store electrical energy removed from said transducers.

55. The energy conversion device of claim 48, wherein the working fluid changes from a liquid to a gas or from a gas to a liquid.

56. The energy conversion device of claim 48, wherein the conditioning electronics are designed or configured to perform one or more of the following functions:

voltage step-up, voltage step-down, and charge control.

57. The energy conversion device of claim 48, further comprising:

one or more batteries are designed or configured to increase the charge of the polymer.

58. The energy conversion device of claim 48, wherein the working fluid in the first chamber is maintained at about a first temperature and the working fluid in the second chamber is maintained at about a second temperature.

59. The energy conversion device of claim 48, further comprising:

a housing enclosing the two or more transducers, the two chambers, the conditioning electronics and the one or more transmission mechanisms.

60. The energy conversion device of claim 48, wherein the polymer comprises a material selected from the group consisting of a silicone elastomer, an acrylic elastomer, a polyurethane, a copolymers comprising PVDF, and combinations thereof.

61. The energy conversion device of claim 48, further comprising:

an insulation layer attached to the polymer wherein the insulation layer is designed or configured to reduce heat transfer to the polymer.

62. The energy conversion device of claim 61, wherein the insulation layer comprises one or more of a plurality of passive polymer layers, compliant inorganic material, wetting liquids and combinations thereof.

63. The energy conversion device of claim 48, further comprising:

one or more sensors connected to said generator.

64. The energy conversion device of claim 63, wherein at least of one of said sensors is designed or configured to monitor a temperature.

65. The energy conversion device of claim 48, wherein the polymer comprises a first portion and a second portion arranged in a manner which causes a change in electric field in response to a deflection applied to at least one of the first portion and the second portion.

66. The energy conversion device of claim 48, wherein the polymer expands to form one of a balloon-like shape, a hemispherical shape, a cylinder shape, or a half-cylinder shape.

67. The energy conversion device of claim 48, wherein said two or more transducers, the first chamber, the second chamber, the conditioning electronics and the one or more transmission mechanisms are fabricated on a semiconductor substrate.

68. The energy conversion device of claim 48, further comprising:

an insert located within said first chamber designed or configured to substantially conform to a contracted shape of the polymer of said first transducer.

69. The energy conversion device of claim 48, further comprising:

an insert located within said second chamber designed or configured to substantially conform to a contracted shape of the polymer of said second transducer.

70. The energy conversion device of claim 48, further comprising;

a plurality of chamber pairs enclosing a volume of a working fluid distributed between said chamber pairs.

71. The energy conversion device of claim 48, wherein the thermal energy is applied to the working fluid in said first chamber to expand said working fluid and wherein the expansion of said working fluid deflects the polymer in said first chamber.

72. The energy conversion device of claim 71, wherein the working fluid comprises one of helium, nitrogen, carbon dioxide, air, water, hydrocarbons, and refrigerants.

73. The energy conversion device of claim 71, wherein the working fluid in said first chamber is transferred to said second chamber via a flow conduit.

74. The energy conversion device of claim 73, wherein the total volume of said working fluid in the first chamber, the second chamber and the flow conduit during said transfer remains substantially constant.

75. The energy conversion device of claim 73, wherein the working fluid in said second chamber is expanded resulting in a temperature reduction in the working fluid.

76. The energy conversion device of claim 73, wherein the working fluid in said second chamber is expanded at a substantially constant temperature.

77. The energy conversion device of claim 48, wherein a first transmission mechanism is designed or configured to receive thermal energy and transfer a portion of thermal energy to said first chamber.

78. The energy conversion device of claim 77, wherein the first transmission mechanism transfers the portion of the thermal energy via a fluid.

79. The energy conversion device of claim 78, wherein the fluid comprises one of water and a hydraulic oil, and a heat transfer fluid comprising hydrocarbons.

80. The energy conversion device of claim 77, wherein the first transmission mechanism comprises a heat exchange mechanism.

81. The energy conversion device of claim 80, wherein the heat exchange mechanism transfers a portion of thermal energy via at least one of heat conduction, heat convection, and radiation heat transfer.

82. The energy conversion device of claim 77, wherein said first transmission mechanism include a combustion chamber for combusting a fuel.

83. The energy conversion device of claim 82, wherein the fuel is a solid fuel, a liquid fuel, a gel fuel or a gaseous fuel.

84. The energy conversion device of claim 77, wherein the fuel is selected from group consisting essentially of propane, butane, natural gas, hydrogen, kerosene, and gasoline, jet fuel, diesel, coal-derived fuels, biomass and other hydrocarbon fuels.

85. The energy conversion device of claim 82, further comprising:

at least one fuel inlet for injecting the fuel into said combustion chamber and at least one exhaust outlet for ejecting a combustion product mixture from said combustion chamber.

86. The energy conversion device of claim 82, further comprising:

an ignition device for initiating combustion in said combustion chamber.

87. The energy conversion device of claim 77, wherein the first transmission mechanism receives thermal energy generated from an external heat source.

88. The energy conversion device of claim 87, wherein the external heat comprises one of a solar heat source, an external combustion heat source, a geothermal heat source, and excess energy from an engine block and a waste heat source.

89. The energy conversion device of claim 48, wherein the polymer in the first chamber is contracted to compress the working fluid in said first chamber.

90. The energy conversion device of claim 89, wherein a portion of thermal energy generated during the compression of said working fluid in said first chamber is transferred via a heat exchanger.

91. The energy conversion device of claim 89, wherein the working fluid comprises one of helium, nitrogen, carbon dioxide, air, refrigerants, hydrocarbons and water.

92. The energy conversion device of claim 89, wherein the working fluid in said first chamber is transferred to said second chamber via a flow conduit.

93. The energy conversion device of claim 92, wherein a total volume of said working fluid in the first chamber, the second chamber and the flow conduit during said transfer remains substantially constant.

94. The energy conversion device of claim 92 wherein the working fluid in said second chamber is expanded resulting in a temperature reduction in the working fluid.

95. The energy conversion device of claim 92 wherein the working fluid in said second chamber is expanded at a substantially constant temperature.

96. The energy conversion device of claim 89, wherein the compression of said working fluid converts a portion said working fluid to a liquid.

97. The energy conversion device of claim 96, wherein the working fluid comprises a material essentially of ammonia and refrigerants.

98. The energy conversion device of claim 89, wherein a first transmission mechanism is designed or configured to cool an external device.

99. The energy conversion device of claim 98, wherein the external device is a semiconductor device.

100. The energy conversion device of claim 98, wherein the external device is a refrigerator.

101. An energy conversion device for convening thermal energy to electrical energy, the energy conversion device comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer wherein the polymer includes pre-strain;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers; and

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer.

119. The energy conversion device of claim 101, wherein the charge control circuitry is designed to add charge to the one or more transducers or remove charge from the one or more transducers.

120. The energy conversion device of claim 101, further comprising:

a logic device.

121. The energy conversion device of claim 120, wherein the logic device is designed or configured to determine an amount of charge to add or to delete from the polymer.

122. The energy conversion device of claim 121, wherein the amount of charge is determined from charge control algorithm.

123. A generator for convening thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers; and

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer and wherein the one or more transmission mechanisms comprises a hydraulic fluid.

124. A generator for converting thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers;

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer; and

iv) one or more sensors connected to said generator wherein at least one of the one or more sensors is designed or configured to monitor at least one of the following quantities;

the deflection in the portion of the polymer, a voltage in the portion of the polymer or a charge in the portion of the polymer.

125. A generator for converting thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers;

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer; and

iv) a logic device.

126. A generator for converting thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manner which causes a change in electric field in response to a deflection applied to a portion of the polymer;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers; and

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer and wherein the polymer includes pre-strain.

127. A generator for converting thermal energy to electrical energy, the generator comprising:

i) one or more transducers, each transducer comprising;

at least two electrodes; and

a polymer arranged in a manna which causes a change in electric field in response to a deflection applied to a portion of the polymer;

ii) conditioning electronics connected to the at least two electrodes and designed or configured to add or remove electrical energy from the one or more transducers; and

iii) one or more transmission mechanisms designed or configured to receive thermal energy and to convert a portion of the thermal energy to mechanical energy, wherein the mechanical energy results in a deflection in the portion of the polymer and wherein the polymer comprises a multiplayer structure.