Passive thermal control system

• US 6,923,249 B1
• Filed: 05/28/2003
• Issued: 08/02/2005
• Est. Priority Date: 05/15/2003
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Porter, Harry H., Valenzuela, Jose, Harvey, Timothy W., Williams, James D.
• Primary Examiner(s): Duong, Tho v
• Application Number:
  US10/447,971
• Time in Patent Office: 797 Days
• Field of Search: 165/41, 165/104.14, 165/42, 165/47, 165/48.1, 165/48.2, 244/173, 244/163, 244/158.A, 136/244, 136/246, 136/293, 343/700.MS
• US Class Current: 165/104.14
• CPC Class Codes: B64G 1/425 Power storage
• CPC Class Codes: B64G 1/443 Photovoltaic cell arrays
• CPC Class Codes: B64G 1/50 for temperature control
• CPC Class Codes: B64G 1/503 Radiator panels
• CPC Class Codes: B64G 1/66 Arrangements or adaptations of apparatus or instruments, not otherwise provided for
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/465 with solar battery as charging system
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/647 Prismatic or flat cells, e.g. pouch cells
• CPC Class Codes: H01M 10/6551 Surfaces specially adapted for heat dissipation or radiation, e.g. fins or coatings
• CPC Class Codes: H01M 10/6554 Rods or plates
• CPC Class Codes: H01M 10/658 by thermal insulation or shielding
• CPC Class Codes: H01M 10/667 the system being an electronic component, e.g. a CPU, an inverter or a capacitor
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A passive thermal control system maintains the operating temperature range of protected equipment within desired limits by controlling the conductive attributes of thermal interfaces and physical relationships within the system so as to achieve a desired thermal balance. In one embodiment, an integrated cell unit (100) includes a solar array (102), a Lithium ion cell (108) and an antenna assembly (114) such as a phased array antenna. In operation, a thermal gradient (116) is defined between the array (102) and the assembly (114) as the assembly (114) radiates heat from the array (102) into space. The operating temperature range of the cell (108) is controlled by appropriate design of the thermal interfaces between the cell (108) and the assembly (114) and/or interfaces within the assembly (114), such as a thermal interface associated with dielectric spacers provided between emitter pairs of the assembly (114).

Claims

1. An integrated antenna and solar array unit, comprising:

a solar array assembly, having an array external surface for receiving solar radiation;

an antenna assembly having an antenna external surface operative to radiate thermal energy therefrom, said antenna external surface facing substantially opposite said array external surface;

said solar array assembly being in thermal communication with said antenna assembly so that thermal energy passes from said solar array assembly to said antenna external surface thereby defining a thermal gradient; and

a battery unit, operatively associated with said solar array assembly and said antenna assembly, disposed in said thermal gradient between said solar array assembly and said antenna assembly.

2. A method as set forth in claim 1, further comprising structure for controlling heat transfer properties between said solar array assembly and said antenna external surface so as to maintain said battery unit within a desired temperature range.

3. A method as set forth in claim 2, wherein said structure comprises a partial insulating layer formed from heat insulating material interposed between said solar array assembly and said antenna external surface, said partial insulating layer extending across a first portion of a heat exchange interface area between said solar array assembly and said antenna external surface and being absent from a second portion of said heat exchange interface area so as to permit heat transfer across said portion via radiation.

4. An integrated antenna and solar array unit as set forth in claim 3, wherein said partial insulating layer is disposed between said battery unit and said antenna external surface.

5. An integrated antenna and solar array unit as set forth in claim 3, wherein said partial insulating layer comprises a continuous sheet of said heat insulating material extending across said first portion of said heat exchange area.

6. An integrated antenna and solar array unit as set forth in claim 1, wherein said antenna assembly comprises two radiating elements separated by said heat insulating material.

7. An integrated antenna and solar array unit as set forth in claim 2, wherein said structure comprises a thermal standoff for providing a spacing between said battery unit and interconnected structure of said integrated antenna and solar array unit.

8. An integrated antenna and solar array unit as set forth in claim 7, wherein said thermal standoff is disposed on a low energy side of said battery unit relative to said thermal gradient.

9. An integrated antenna and solar array unit as set forth in claim 1, further comprising a charge control system for controlling charging of the battery source to stay within desired charge levels.

10. An integrated antenna and solar array unit, comprising:

a solar array assembly, having an array external surface for receiving solar radiation;

an antenna assembly having an antenna external surface operative to radiate thermal energy therefrom, said antenna external surface facing substantially opposite said array external surface;

said solar array assembly being in thermal communication with said antenna assembly so that thermal energy passes from said solar array assembly to said antenna external surface, thereby defining a thermal gradient; and

a partial insulating layer formed from heat insulating material interposed between said array external surface and said antenna external surface, said partial insulating layer extending across a first portion of a heat exchange interface area between said array external surface and said antenna external surface and being absent from a second portion of said heat exchange interface area so as to permit heat dissipation across said second portion to said antenna external surface via radiation.

11. A unit as set forth in claim 10, wherein said thermal communication between said solar array assembly and said antenna assembly is primarily via radiation with minimum conduction.

12. An integrated antenna and solar array unit as set forth in claim 10, further comprising a controlled component having a desired operating temperature range, said controlled component disposed in said thermal gradient between said array external surface and said antenna external surface.

13. An integrated antenna and solar array unit as set forth in claim 12, wherein said controlled component comprises a battery unit.

14. An integrated antenna and solar array unit as set forth in claim 13, further comprising a thermal standoff for providing a spacing between said battery unit and interconnected structure of said integrated antenna and solar array unit.

15. A method for use in constructing an integrated antenna and solar array unit, said unit including a solar array assembly having an array external surface for receiving solar radiation, an antenna assembly having an antenna external surface operative to radiate thermal energy therefrom, said antenna external surface, said solar array assembly being in thermal communication with said antenna assembly so that thermal energy passes from said solar array assembly to said antenna external surface thereby defining a thermal gradient, and a battery unit disposed in said thermal gradient between said array external surface and said antenna external surface, said method comprising the steps of:

determining operating parameters for said unit related to generation of heat associated with said solar array unit;

determining a desired operating temperature range of said battery; and

using said operating parameters and said desired operating temperature range to configure a thermal interface between said array external surface and said antenna external surface so as to provide desired heat dissipation from said solar array unit via said antenna external surface.

16. A method as set forth in claim 15, wherein said thermal communication between said solar assembly and said antenna assembly is primarily via radiation with minimum conduction.

17. A method as set forth in claim 15, wherein said step of using comprises disposing a partial insulating layer at said thermal interface, wherein said partial insulating layer extends across a first portion of said thermal interface and is absent from a second portion of said thermal interface source to permit heat dissipation across said second portion to said antenna external surface.

18. A method as set forth in claim 15, further comprising the step of disposing a thermal standoff between said battery and interconnected structure of said integrated antenna and solar array unit.