Thermal barrier structure for containing thermal runaway propagation within a battery pack

• US 8,541,126 B2
• Filed: 08/31/2009
• Issued: 09/24/2013
• Est. Priority Date: 08/31/2009
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Hermann, Weston Arthur, Kohn, Scott Ira, Mehta, Vineet Haresh, Beck, David G.
• Primary Examiner(s): RHEE, JANE J
• Application Number:
  US12/584,074
• Publication Number:
  US 20100136404A1
• Time in Patent Office: 1,485 Days
• Field of Search: 429/149, 429/152, 429/120
• US Class Current: 429/120
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/643 Cylindrical cells
• CPC Class Codes: H01M 10/647 Prismatic or flat cells, e.g. pouch cells
• CPC Class Codes: H01M 10/6552 Closed pipes transferring heat by thermal conductivity or phase transition, e.g. heat pipes
• CPC Class Codes: H01M 10/6555 arranged between the cells
• CPC Class Codes: H01M 10/6557 arranged between the cells
• CPC Class Codes: H01M 10/6568 characterised by flow circuits, e.g. loops, located externally to the cells or cell casings
• CPC Class Codes: H01M 10/658 by thermal insulation or shielding
• CPC Class Codes: H01M 10/66 Heat-exchange relationships between the cells and other systems, e.g. central heating systems or fuel cells
• CPC Class Codes: H01M 50/211 adapted for pouch cells
• CPC Class Codes: H01M 50/213 adapted for cells having curved cross-section, e.g. round or elliptic H01M50/209, H01M50/216 take precedence
• CPC Class Codes: H01M 50/24 adapted for protecting batteries from their environment, e.g. from corrosion thermal insulation H01M10/658
• CPC Class Codes: H01M 50/293 characterised by the material
• CPC Class Codes: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery pack is provided that includes one or more thermal barrier elements, the thermal barrier elements dividing the cells within the battery pack into groups of cells. The thermal barrier elements that separate the cells into groups prevent a thermal runaway event initiated in one group of cells from propagating to the cells within a neighboring group of cells.

Claims

1. A battery pack, comprising:

a multi-sided battery pack enclosure comprising first and second battery pack enclosure walls and upper and lower battery pack enclosure walls;

a plurality of cells completely contained within said battery pack enclosure; and

at least one thermal barrier element dividing the battery pack into a plurality of cell groups, wherein said at least one thermal barrier element extends completely between said first and second battery pack enclosure walls, wherein said at least one thermal barrier element extends completely between said upper and lower battery pack enclosure walls, wherein each cell group of said plurality of cells groups is completely segregated from other cell groups of said plurality of cell groups by said at least one thermal barrier element, wherein each of said plurality of cell groups includes at least two cells, wherein each of said at least one thermal barrier elements is comprised of a central portion sandwiched between a pair of layers, wherein said central portion exhibits a high thermal conductivity and each layer of said pair of layers is comprised of a low thermal conductivity material with a melting temperature of at least 300°

C. and a thermal conductivity of less than 20 W/mK at 25°

C., and wherein each of said at least one thermal barrier elements prevents a thermal runaway event in a first cell group of said plurality of cell groups from initiating a second thermal runaway event in an adjacent cell group of said plurality of cell groups.

2. The battery pack of claim 1, wherein said melting temperature of said low thermal conductivity material comprising each layer of said pair of layers comprising said at least one thermal barrier elements is greater than 600°

C.

3. The battery pack of claim 1, wherein said melting temperature of said low thermal conductivity material comprising each layer of said pair of layers comprising said at least one thermal barrier elements is greater than 1500°

C.

4. The battery pack of claim 1, wherein said low thermal conductivity material comprising each layer of said pair of layers comprising said at least one thermal barrier elements has a thermal conductivity of less than 1 W/mK at 25°

C.

5. The battery pack of claim 1, wherein said low thermal conductivity material comprising each layer of said pair of layers comprising said at least one thermal barrier elements has a thermal conductivity of less than 0.3 W/mK at 25°

C.

6. The battery pack of claim 1, wherein said low thermal conductivity material comprising each layer of said pair of layers comprising said at least one thermal barrier elements is selected from the group consisting of aluminum oxide, magnesium oxide, silicon dioxide, silicon nitride, silicon carbide, alumina silicate, calcium-silicate, calcium-magnesium-silicate, aramid, intumescent materials, silicone coated fiberglass, acrylic coated fiberglass, vermiculite coated fiberglass, graphite coated fiberglass, polytetrafluoroethylene coated fiberglass, or some combination thereof.

7. The battery pack of claim 1, wherein said central portion of each of said at least one thermal barrier elements further comprises at least one channel configured to contain a heat transfer fluid, wherein said at least one channel is integrated within said central portion of each of said at least one thermal barrier elements.

8. The battery pack of claim 7, wherein each of said at least one channels is coupled to a passive cooling system, and wherein said passive cooling system further comprises a coolant reservoir.

9. The battery pack of claim 7, wherein each of said at least one channels is coupled to an active cooling system, and wherein said active cooling system further comprises a coolant reservoir and a coolant pump.

10. The battery pack of claim 9, wherein said active cooling system further comprises a heat exchanger.

11. The battery pack of claim 7, wherein each of said at least one channels is coupled to a heat sink.

12. The battery pack of claim 1, wherein said high thermal conductivity of said central portion of each of said at least one thermal barrier elements is greater than 50 W/mK.

13. The battery pack of claim 12, wherein said high thermal conductivity of said central portion is greater than 100 W/mK and said thermal conductivity of said low thermal conductivity material comprising each layer of said pair of layers is less than 1 W/mK.

14. The battery pack of claim 1, wherein said central portion of each of said at least one thermal barrier elements is coupled to a heat sink.