# US 7,743,785 B2 · Passive pressure relief device system based on thermobattery for a compressed gas storage tank > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,743,785 B2 - Document ID: US7743785B2 - Status: Granted - Kind: B2 - Application number: 11/437,545 - Filed: 2006-05-19 - Published: 2007-11-22 - Granted: 2010-06-29 - Earliest claimed: 2006-05-19 - Assignees: GM Global Technology Operations LLC - Inventors: Thorsten Rohwer; Christian Koenig - Web page: https://patentgrep.com/patent/US7743785B2 ## CPC - H01M 6/36: containing electrolyte and made operational by physical means, e.g. thermal cells - F16K 31/002: {actuated by temperature variation (thermo-electric F16K31/025)} - F16K 31/025: {actuated by thermo-electric means} - F17C 2205/0332: Safety valves or pressure relief valves - H01M 6/50: Methods or arrangements for servicing or maintenance, e.g. for maintaining operating temperature (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - Y02E 60/32: Hydrogen storage - Y10T 137/1963: Temperature - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - F16K: VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING {(devices for emptying and evacuating the excess liquid in valves or conduits F16L55/07)} - F17C: VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00; construction or assembling of bulk storage containers employing civil-engineering techniques E04H7/00; variable-capacity gas-holders F17B; liquefaction or refrigeration machines, plants, or systems F25) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A compressed gas storage system with an incorporated pressure relief device is disclosed. The compressed gas storage system comprises a tank for storing a compressed gas, a battery in the direct surroundings of the tank, and a relief valve in communication with the tank. The relief valve is configured to be responsive to electrical current generated by the battery. The battery is configured to define an electrically active state when it reaches a temperature above a maximum safe operating temperature of the compressed gas storage system. The electrically active state of the battery is characterized by the generation of sufficient electrical current to open the relief valve which permits gas to escape from the tank. In another embodiment, a thermocouple in combination with a conducting metal may be substituted for the battery. ## Claims ### Claim 1 A compressed gas storage system comprising a tank for storing a compressed gas, a battery in physical contact with said tank, and a relief valve in communication with said tank, wherein: said tank comprises at least one curved outer surface; said relief valve is configured to be responsive to electrical current generated by said battery; said battery is configured to define an electrically active state when it reaches a temperature above a maximum safe operating temperature of said compressed gas storage system; said battery comprises a continuous multilayer structure wrapped around said tank so as to conform to and cover said curved outer surface of said tank, said continuous multilayer structure comprising an anode layer in direct physical contact with said tank, a cathode layer disposed over said anode layer, and a thermally activated electrolyte layer separating said anode layer and said cathode layer; and said electrically active state of said battery is characterized by the generation of sufficient electrical current to open said relief valve, permitting gas to escape from said tank. ### Claim 2 (depends on 1) The compressed gas storage system of claim 1, wherein said compressed gas storage system defines an operational temperature gradient extending from a minimum operational temperature to a maximum operational temperature. ### Claim 3 (depends on 1) The compressed gas storage system of claim 1, wherein said maximum safe operating temperature is at least high enough to exceed maximum operational temperature of said compressed gas storage system. ### Claim 4 (depends on 1) The compressed gas storage system of claim 1, wherein said compressed gas storage system defines an operational temperature gradient. ### Claim 5 (depends on 1) The compressed gas storage system of claim 1, wherein a maximum safe operating temperature is at least 20° C. greater than said temperature gradient ### Claim 6 (depends on 1) The compressed gas storage system of claim 1, wherein said electrolyte is frozen under normal environmental temperatures. ### Claim 7 (depends on 6) The compressed gas storage system of claim 6, wherein said electrolyte is not ionic conductive under normal environmental conditions. ### Claim 8 (depends on 1) The compressed gas storage system of claim 1, wherein said compressed gas tank stores hydrogen gas. ### Claim 9 (depends on 8) The compressed gas storage system of claim 8, wherein said compressed gas tank supplies hydrogen gas to a fuel cell. ### Claim 10 (depends on 1) A vehicle comprising said compressed gas storage system as claimed in claim 1, wherein said compressed gas storage system supplies hydrogen to a fuel cell system, wherein said fuel cell system serves as a source of motive power for said vehicle. ### Claim 11 (depends on 10) The vehicle of claim 10, wherein said maximum safe operating temperature is at least high enough to exceed a maximum operating temperature of said fuel cell system. ### Claim 12 (depends on 1) The compressed gas storage system of claim 1, wherein said compressed gas tank stores natural gas. ### Claim 13 (depends on 12) The compressed gas storage system of claim 12, wherein said compressed gas tank supplies natural gas to a combustion engine. ### Claim 14 (depends on 1) A vehicle comprising said compressed gas storage system as claimed in claim 1, wherein said compressed gas storage system supplies natural gas to a combustion engine, wherein said combustion engine serves as a source of motive power for said vehicle. ### Claim 15 A method of heat activated pressure relief of a tank for storing a compressed gas, the method comprises: providing a battery comprising a continuous multilayer structure wrapped around said tank so as to conform to and cover a curved outer surface of said tank, said continuous multilayer structure comprising an anode layer in direct physical contact with said tank, a cathode layer disposed over said anode layer, and a thermally activated electrolyte layer separating said anode layer and said cathode layer; melting at least a portion of said thermally activated electrolyte layer by a spot heat source directed at any portion of said tank covered by said battery; activating said battery electrically by said melting of said portion of said thermally activated electrolyte; generating an electrical current by said electrical activation of said battery; opening a relief valve configured to be responsive to sufficient generation of said electrical current by said battery, wherein said relief valve is in communication with said tank; and releasing gas from said tank by the opening of said relief valve to relieve pressure within said tank.