Mechanical and thermal improvements in metal hydride batteries, battery modules and battery packs

• US 20020182493A1
• Filed: 04/12/2002
• Published: 12/05/2002
• Est. Priority Date: 10/25/1993
• Status: Active Grant

• Current Assignee: Chevron Technology Ventures LLC (Chevron Corp.)
• Original Assignee: Ovonic Battery Company, Inc (BASF SE)
• Inventors: Ovshinsky, Stanford R., Corrigan, Dennis A., Holland, Arthur, Gow, Philippe, Higley, Lin, Osgood, Anthony, Venkatesan, Srinivasan, Fillmore, Donn, Laming, Kenneth, Himmler, Ronald, Karditsas, Nick, Dhar, Subhash K.
• Granted Patent: US 6,878,485 B2
• Time in Patent Office: Days
• US Class Current: 429/176
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/443 in response to temperature
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/617 for achieving uniformity or desired distribution of temperature
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/63 Control systems charging or discharging in response to temperature H01M10/44 , H01M10/443; measurement of temperature H01M10/48 , H01M10/486
• CPC Class Codes: H01M 10/635 based on ambient temperature
• CPC Class Codes: H01M 10/647 Prismatic or flat cells, e.g. pouch cells
• CPC Class Codes: H01M 10/651 characterised by parameters specified by a numeric value or mathematical formula, e.g. ratios, sizes or concentrations
• CPC Class Codes: H01M 10/652 characterised by gradients for achieving a desired temperature gradient H01M10/617
• CPC Class Codes: H01M 10/653 characterised by electrically insulating or thermally conductive materials
• CPC Class Codes: H01M 10/654 located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
• CPC Class Codes: H01M 10/655 Solid structures for heat exchange or heat conduction
• 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 10/6557 arranged between the cells
• CPC Class Codes: H01M 10/6562 with free flow by convection only
• CPC Class Codes: H01M 10/6563 with forced flow, e.g. by blowers
• CPC Class Codes: H01M 10/6567 Liquids
• CPC Class Codes: H01M 10/658 by thermal insulation or shielding
• CPC Class Codes: H01M 50/209 : adapted for prismatic or rectangular cells H01M50/216 takes precedence
• CPC Class Codes: H01M 50/30 : Arrangements for facilitating escape of gases
• CPC Class Codes: H01M 50/317 : Re-sealable arrangements
• CPC Class Codes: H01M 50/55 : on the same side of the cell
• CPC Class Codes: H01M 50/553 : Terminals adapted for prismatic, pouch or rectangular cells
• CPC Class Codes: H01M 50/562 : characterised by the material
• CPC Class Codes: H01M 50/566 : by welding, soldering or brazing
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• CPC Class Codes: Y10T 29/4911 : including sealing

Abstract

Mechanically and thermally improved rechargeable batteries, modules and fluid-cooled battery pack systems. The battery is prismatic in shape with an optimized thickness to width to height aspect ratio which provides the battery with balanced optimal properties when compared with prismatic batteries lacking this optimized aspect ratio. The optimized thickness, width and height allow for maximum capacity and power output, while eliminating deleterious side affects. The battery case design allows for unidirectional expansion which is readily compensated for by applying external mechanical compression counter to that direction. In the module, the batteries are bound within a module bundling/compression means under external mechanical compression which is optimized to balance outward pressure due to expansion and provide additional inward compression to reduce the distance between the positive and negative electrodes, thereby increasing overall battery power. The fluid-cooled battery pack includes; 1) a battery-pack case having coolant inlet and outlet; 2) battery modules within the case such that the battery module is spaced from the case walls and from other battery modules to form coolant flow channels along at least one surface of the bundled batteries; and 3) at least one coolant transport means. The width of the coolant flow channels allows for maximum heat transfer. Finally the batteries, modules and packs can also include means for providing variable thermal insulation to at least that portion of the rechargeable battery system which is most directly exposed to said ambient thermal condition, so as to maintain the temperature of the rechargeable battery system within the desired operating range thereof under variable ambient conditions.

Claims

1. A mechanically improved rechargeable battery, said battery including:

a battery case including a positive electrode terminal and a negative electrode terminal;

at least one positive electrode disposed within said battery case and electrically connected to said positive electrode terminal;

at least one negative electrode disposed within said battery case and electrically connected to said negative electrode terminal;

at least one separator disposed between said positive and negative electrodes within said battery case, said separator electrically insulating said positive electrode from said negative electrode, but still allowing for chemical interaction between said positive and negative electrodes; and

battery electrolyte disposed within said battery case, said battery electrolyte surrounding and wetting said positive electrode, said negative electrode, and said separator;

said battery case being prismatic in shape and having an optimized thickness to width to height aspect ratio.

2. The mechanically improved rechargeable battery of claim 1, wherein said battery case is formed from a material which is thermally conductive, mechanically strong and rigid, and resistant to corrosion.

3. The mechanically improved rechargeable battery of claim 2, wherein said prismatic battery case is formed from metal.

4. The mechanically improved rechargeable battery of claim 3, wherein said metal case is formed from a stainless steel.

5. The mechanically improved rechargeable battery of claim 1, wherein said case is formed from a case top which includes said positive battery electrode terminal and said negative battery electrode terminal, and a battery case can into which said electrodes are disposed.

6. The mechanically improved rechargeable battery of claim 5, wherein said case top includes an annular shroud defining the periphery of at least one opening through said top and said terminals have a sealing lip around their circumference, said terminals crimp sealed into said annular shroud at said sealing lip.

7. The mechanically improved rechargeable battery of claim 6, wherein said case top, said case can, and said annular shroud are formed of 304L stainless steel.

8. The mechanically improved rechargeable battery of claim 6, wherein an elastomeric, dielectric seal is positioned between said sealing lip and said annular shroud.

9. The mechanically improved rechargeable battery of claim 8, wherein said elastomeric, dielectric seal is formed of a hydrogen impermeable polysulfone material.

10. The mechanically improved rechargeable battery of claim 1, further including a pressure vent for releasing internal pressure of the battery to the surrounding atmosphere.

11. The mechanically improved rechargeable battery of claim 10, wherein said pressure vent is affixed in an opening within at least one of said terminals.

12. The mechanically improved rechargeable battery of claim 10, wherein said pressure vent includes:

a vent housing having a hollow interior area in gaseous communication with said surrounding atmosphere and the interior of said case via said opening,

a pressure release piston positioned within said hollow interior area, said pressure release piston sized to seal said axial opening and having a seal groove on its surface opposite said axial opening;

an elastomeric, dielectric seal mounted within said seal groove, said seal groove configured to encapsulate all but one surface of said seal, thereby leaving the non-encapsulated surface of said seal exposed; and

a compression spring positioned to urge said pressure release piston to compress said seal in said seal groove and block said axial opening in said terminal.

13. The mechanically improved rechargeable battery of claim 12, wherein said elastomeric, dielectric seal is formed of a hydrogen impermeable polysulfone material.

14. The mechanically improved rechargeable battery of claim 1, further including at least one comb forming an electrical connection between internal electrode tabs and said terminals.

15. The mechanically improved rechargeable battery of claim 14, wherein said at least one comb is an electrically conductive bar having multiple parallel slots into which said internal electrode tabs are friction fit.

16. The mechanically improved rechargeable battery of claim 15, wherein said at least one comb is formed of copper, copper alloy, nickel coated copper or nickel coated copper alloy.

17. The mechanically improved rechargeable battery of claim 1, wherein said terminals are formed of copper, copper alloy, nickel coated copper or nickel coated copper alloy.

18. The fluid cooled battery-pack system of claim 1, wherein said at least one battery electrode separator disposed between said positive and negative electrodes includes separators surrounding each electrode.

19. The fluid cooled battery-pack system of claim 1, wherein said separators are formed from polypropylene having an oriented grain or groove structure.

20. The fluid cooled battery-pack system of claim 19, wherein said separators are positioned such that said oriented grain structure is aligned along the height direction of said at least one positive electrode and said at least one negative electrode.

21. The mechanically improved rechargeable battery of claim 3, wherein the exterior of said metal prismatic battery case is electrically insulated from the environment by a non-conductive polymer coating.

22. The mechanically improved rechargeable battery of claim 21, wherein said non-conductive polymer coating is a layer of electrically insulating polymer tape.

23. The mechanically improved rechargeable battery of claim 1, wherein said positive and negative battery electrodes are disposed in said case such that their respective electrical collection tabs are disposed opposite one another at the top of said case.

24. The mechanically improved rechargeable battery of claim 23, wherein said positive and negative battery electrodes have notched corners where the opposite polarity electrode electrical collection tabs are located, thereby avoiding shorts between the electrodes and eliminating unused, dead-weight electrode material.

25. The mechanically improved rechargeable battery of claim 1, wherein said battery includes 19 positive electrodes and 20 negative electrodes alternatingly disposed within said case.

26. The mechanically improved rechargeable battery of claim 3, wherein the interior said metal prismatic battery case is electrically insulated from the electrodes and electrolyte.

27. The mechanically improved rechargeable battery of claim 27, wherein the interior said metal prismatic battery case is electrically insulated from the electrodes and electrolyte by coating the interior of said battery case with an electrically insulating polymer material.

28. The mechanically improved rechargeable battery of claim 26, wherein the interior said metal prismatic battery case is electrically insulated from the electrodes and electrolyte by placing the electrodes and electrolyte in a polymer bag which is sealed and inserted into the battery case.

29. The mechanically improved rechargeable battery of claim 1, wherein said negative electrodes are formed from thermally conductive sintered metal hydride electrode material.

30. The mechanically improved rechargeable battery of claim 29, wherein said thermally conductive sintered metal hydride electrodes are in thermal contact with the battery case.

31. In a rechargeable battery system formed from at least one interconnected rechargeable battery, said rechargeable battery system exposed to ambient thermal conditions so as to develop a degradative thermal operating temperature in said rechargeable battery system, the improvement comprising:

means for providing variable thermal insulation to at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition, so as to maintain the temperature of the rechargeable battery system within the desired operating range thereof under variable ambient conditions.

32. The rechargeable battery system of claim 31, wherein said rechargeable battery system includes a single rechargeable battery.

33. The rechargeable battery system of claim 31, wherein said rechargeable battery system includes multiple electrically interconnected rechargeable batteries bound into a battery module.

34. The rechargeable battery system of claim 31, wherein said rechargeable battery system includes multiple electrically interconnected rechargeable batteries bound into multiple battery modules which are disposed in a case to form a battery pack system.

35. The rechargeable battery system of claim 31, wherein said means for providing variable insulation includes temperature sensor means, compressible thermal insulation means and a means to compress the compressible thermal insulation means in response to the temperature detected by the thermal sensor.

36. The rechargeable battery system of claim 35, wherein said thermal sensors includes electronic sensors, said compressible thermal insulation means includes a compressible foam or fiber insulation and said means to compress the compressible thermal insulation means includes piston devices which variably increases or decreases the compression upon the compressible foam or fiber insulation in response to signals from the electronic sensors.

37. The rechargeable battery system of claim 35, wherein said thermal sensors and said means to compress the compressible thermal insulation means are combined as a single unit.

38. The rechargeable battery system of claim 37, wherein said combined, single-unit, thermal-sensor/insulation-compressor includes a bimetallic strip which allows the compressible thermal insulation means to expand into place to protect the battery system from cold ambient conditions and compresses the insulation to remove its insulating effect from the battery system under warm ambient conditions.

39. The rechargeable battery system of claim 32, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes the entire rechargeable battery.

40. The rechargeable battery system of claim 33, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes the entire battery module.

41. The rechargeable battery system of claim 33, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes only the ends of the battery module.

42. The rechargeable battery system of claim 34, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes all of said multiple battery modules which are disposed in said case to form said battery pack system.

43. The rechargeable battery system of claim 34, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes only the ends of at least one of said multiple battery modules which are disposed in said case to form said battery pack system.

44. The rechargeable battery system of claim 32, wherein said at least that portion of said rechargeable battery system which is most directly exposed to said ambient thermal condition includes only the ends of all of said multiple battery modules which are disposed in said case to form said battery pack system.