# US 2025/0148846 A1 · Detection and warning of thermal hazard in electrical energy storage systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2025/0148846 A1 - Document ID: US20250148846A1 - Status: Published application - Kind: A1 - Application number: 18/930,435 - Filed: 2024-10-29 - Published: 2025-05-08 - Earliest claimed: 2023-11-08 - Assignees: Volvo Truck Corporation - Applicants: Volvo Truck Corporation - Inventors: Faisal ALTAF; Haresh VISWANATHAN; Umut ANAS - Web page: https://patentgrep.com/patent/US20250148846A1 ## CPC - G01R 31/382: Arrangements for monitoring battery or accumulator variables, e.g. SoC - G07C 5/0808: {Diagnosing performance data (testing of vehicles G01M17/00; testing of electrical installation on vehicles G01R31/005)} - G01R 27/025: {Measuring very high resistances, e.g. isolation resistances, i.e. megohm-meters} - G07C 5/006: {Indicating maintenance} - G07C 5/0816: {Indicating performance data, e.g. occurrence of a malfunction} - H01M 10/4207: {for several batteries or cells simultaneously or sequentially} - H01M 10/425: {Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00)} - H01M 10/4285: {Testing apparatus} - H01M 10/48: Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) - B60L 3/0046: {relating to electric energy storage systems, e.g. batteries or capacitors} - G01R 31/396: Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery - H01M 2010/4278: {Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G07C: TIME OR ATTENDANCE REGISTERS; REGISTERING OR INDICATING THE WORKING OF MACHINES; GENERATING RANDOM NUMBERS; VOTING OR LOTTERY APPARATUS; ARRANGEMENTS, SYSTEMS OR APPARATUS FOR CHECKING NOT PROVIDED FOR ELSEWHERE - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES ## Abstract A computer system detects an isolation fault in an electrical energy storage system comprising multiple electrical energy storage packs connected in parallel to a voltage bus. The electrical energy storage packs each comprising a set of electrical energy storage cells. The system disconnects all but one electrical energy storage pack from the voltage bus; determines an isolation resistance for each of the disconnected electrical energy storage packs, determines electrical energy storage cell temperatures for at least two cells in each of the disconnected electrical energy storage packs, and provides a first thermal runaway warning signal when the isolation resistance is below a predetermined threshold, and a second thermal runaway warning signal when one of the electrical energy storage cell temperatures of an electrical energy storage pack exceeds a temperature. ## Claims ### Claim 1 A computer system comprising processing circuitry configured to: detect an isolation fault in an electrical energy storage system comprising multiple electrical energy storage packs connected in parallel to a voltage bus, the electrical energy storage packs each comprising a set of electrical energy storage cells; disconnect all but one electrical energy storage pack from the voltage bus; determine an isolation resistance for each of the disconnected electrical energy storage packs, determine electrical energy storage cell temperatures for at least two cells in each of the disconnected electrical energy storage packs, provide a first thermal runaway warning signal when the isolation resistance is below a predetermined threshold, and provide a second thermal runaway warning signal when one of the electrical energy storage cell temperatures of an electrical energy storage pack exceeds a temperature threshold, and a first temperature difference between any two electrical energy storage cells of the same electrical energy storage pack exceeds a first temperature difference threshold, and provide a third thermal runaway warning signal when one of the electrical energy storage cell temperatures of an electrical energy storage pack exceeds the temperature threshold, and a second temperature difference between any two electrical energy storage cells of the same electrical energy storage pack exceeds a second temperature difference threshold. ### Claim 2 (depends on 1) The computer system of claim 1, wherein the processing circuitry is further configured to: provide the first thermal runaway warning signal when a measured isolation resistance of a single pole of an electrical energy storage pack is below a single pole resistance threshold or if a measured isolation resistance of two poles of an electrical energy storage pack is below a two-pole resistance threshold. ### Claim 3 (depends on 2) The computer system of claim 2, wherein the two-pole resistance threshold is higher than the single pole resistance threshold. ### Claim 4 (depends on 1) The computer system of claim 1, wherein the processing circuitry is further configured to: provide the second thermal runaway warning signal only when the first temperature difference between the two electrical energy storage cells is equal to or exceeds the first temperature difference threshold for a time duration that exceeds or is equal to a predetermined time duration threshold. ### Claim 5 (depends on 1) The computer system of claim 1, wherein the first temperature difference threshold is lower than the second temperature difference threshold. ### Claim 6 (depends on 1) The computer system of claim 1, wherein the processing circuitry is further configured to: in response to any of the warning signals, provide an output message to a user interface. ### Claim 7 (depends on 1) The computer system of claim 1, wherein the processing circuitry is further configured to: determine which one of the electrical energy storage packs has the highest isolation resistance, wherein the one electrical energy storage pack remains connected to the voltage bus. ### Claim 8 (depends on 1) The computer system of claim 1, wherein the processing circuitry is further configured to: calculate the first temperature difference based on cell temperature measurements from two cells of each electrical energy storage pack, and receive, over a communication interface, an indication that the second temperature difference exceeds or is equal to the second temperature difference threshold from a pack management unit of the respective electrical energy storage pack. ### Claim 9 (depends on 1) An electric energy storage system comprising the computer system of claim 1. ### Claim 10 (depends on 9) A vehicle comprising the electrical energy storage system of claim 9. ### Claim 11 A computer-implemented method, comprising: detecting, by processing circuitry of a computer system, an isolation fault in an electrical energy storage system comprising multiple electrical energy storage packs connected in parallel to a voltage bus, the electrical energy storage packs each comprising a set of electrical energy storage cells; disconnecting, by the processing circuitry, all but one electrical energy storage pack from the voltage bus; determining, by the processing circuitry, an isolation resistance for each of the disconnected electrical energy storage packs, determining, by the processing circuitry, electrical energy storage cell temperatures for at least two cells in each of the disconnected electrical energy storage packs, providing, by the processing circuitry, a first thermal runaway warning signal when the isolation resistance is below a predetermined threshold, and providing, by the processing circuitry, a second thermal runaway warning signal when one of the electrical energy storage cell temperatures of an electrical energy storage pack exceeds a temperature threshold, and a first temperature difference between any two electrical energy storage cells of the same electrical energy storage pack exceeds a first temperature difference threshold, and providing, by the processing circuitry, a third thermal runaway warning signal when one of the electrical energy storage cell temperatures of an electrical energy storage pack exceeds the temperature threshold, and a second temperature difference between any two electrical energy storage cells of the same electrical energy storage pack exceeds a second temperature difference threshold. ### Claim 12 (depends on 11) The method of claim 11, comprising: providing by the processing circuitry, the first thermal runaway warning signal when a measured isolation resistance of a single pole of an electrical energy storage pack is below a single pole resistance threshold or if a measured isolation resistance of two poles of an electrical energy storage pack is below a two-pole resistance threshold. ### Claim 13 (depends on 12) The method of claim 12, wherein the two-pole resistance threshold is higher than the single pole resistance threshold. ### Claim 14 (depends on 11) The method of claim 11, comprising: providing, by the processing circuitry, the second thermal runaway warning signal only when the first temperature difference between the two electrical energy storage cells is equal to or exceeds the first temperature difference threshold for a time duration that exceeds or is equal to a predetermined time duration threshold. ### Claim 15 (depends on 11) The method of claim 11, wherein the first temperature difference threshold is lower than the second temperature difference threshold. ### Claim 16 (depends on 11) The method of claim 11, comprising: in response to any of the warning signals, providing, by the processing circuitry, an output message to a user interface. ### Claim 17 (depends on 11) The method of claim 11, comprising: determining, by the processing circuitry, which one of the electrical energy storage packs has the highest isolation resistance, wherein the one electrical energy storage pack remains connected to the voltage bus. ### Claim 18 (depends on 11) The method of claim 11, comprising: calculating, by the processing circuitry, the first temperature difference based on cell temperature measurements from two cells of each electrical energy storage pack, and receive, by the processing circuitry over a communication interface, an indication that the second temperature difference exceeds or is equal to the second temperature difference threshold from a pack management unit of the respective electrical energy storage pack. ### Claim 19 (depends on 11) A computer program product comprising program code for performing, when executed by the processing circuitry, the method of claim 11. ### Claim 20 (depends on 11) A non-transitory computer-readable storage medium comprising instructions, which when executed by the processing circuitry, cause the processing circuitry to perform the method of claim 11.