# US 8,541,126 B2 · Thermal barrier structure for containing thermal runaway propagation within a battery pack > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,541,126 B2 - Document ID: US8541126B2 - Status: Granted - Kind: B2 - Application number: 12/584,074 - Filed: 2009-08-31 - Published: 2010-06-03 - Granted: 2013-09-24 - Earliest claimed: 2009-08-31 - Assignees: Tesla Motors, Inc. - Applicants: Weston Arthur Hermann; Scott Ira Kohn; Vineet Haresh Mehta; David G. Beck - Inventors: Weston Arthur Hermann; Scott Ira Kohn; Vineet Haresh Mehta; David G. Beck - Web page: https://patentgrep.com/patent/US8541126B2 ## CPC - H01M 50/24: adapted for protecting batteries from their environment, e.g. from corrosion (thermal insulation H01M10/658) - H01M 6/42: Grouping of primary cells into batteries (H01M6/40 takes precedence) - H01M 10/613: Cooling or keeping cold - H01M 10/625: Vehicles - H01M 10/643: Cylindrical cells - H01M 10/647: Prismatic or flat cells, e.g. pouch cells - H01M 10/6552: Closed pipes transferring heat by thermal conductivity or phase transition, e.g. heat pipes - H01M 10/6555: arranged between the cells - H01M 10/6557: arranged between the cells - H01M 10/6568: characterised by flow circuits, e.g. loops, located externally to the cells or cell casings - H01M 10/658: by thermal insulation or shielding - H01M 10/66: Heat-exchange relationships between the cells and other systems, e.g. central heating systems or fuel cells - H01M 50/211: adapted for pouch cells - H01M 50/213: adapted for cells having curved cross-section, e.g. round or elliptic (H01M50/209, H01M50/216 take precedence) - H01M 50/293: characterised by the material - Y02E 60/10: Energy storage using batteries - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## 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 ### Claim 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. ### Claim 2 (depends on 1) 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. ### Claim 3 (depends on 1) 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. ### Claim 4 (depends on 1) 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. ### Claim 5 (depends on 1) 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. ### Claim 6 (depends on 1) 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. ### Claim 7 (depends on 1) 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. ### Claim 8 (depends on 7) 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. ### Claim 9 (depends on 7) 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. ### Claim 10 (depends on 9) The battery pack of claim 9, wherein said active cooling system further comprises a heat exchanger. ### Claim 11 (depends on 7) The battery pack of claim 7, wherein each of said at least one channels is coupled to a heat sink. ### Claim 12 (depends on 1) 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. ### Claim 13 (depends on 12) 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. ### Claim 14 (depends on 1) 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.