# US 11,309,704 B2 · Battery protection systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,704 B2 - Document ID: US11309704B2 - Status: Granted - Kind: B2 - Application number: 16/676,107 - Filed: 2019-11-06 - Published: 2020-05-14 - Granted: 2022-04-19 - Earliest claimed: 2019-11-06 - Assignees: O2Micro, Inc. - Applicants: O2Micro Inc. - Inventors: Guoxing Li - Web page: https://patentgrep.com/patent/US11309704B2 ## CPC - H02H 7/18: for batteries; for accumulators - H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)} - G01K 13/00: Thermometers specially adapted for specific purposes - H01M 10/425: {Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00)} - H01M 10/4257: {Smart batteries, e.g. electronic circuits inside the housing of the cells or batteries} - 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) - H01M 10/486: {for measuring temperature} - H02H 3/085: {making use of a thermal sensor, e.g. thermistor, heated by the excess current (also responsive to the temperature of the protected device H02H5/041, thermal images H02H6/00)} - H02H 5/044: {using a semiconductor device to sense the temperature} - H02J 7/65: against overtemperature - Y02E 60/10: Energy storage using batteries - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) - 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 protection system includes a sensor, a primary protection circuit, coupled to the sensor, and a secondary protection circuit, coupled to the primary protection circuit and the sensor. The sensor is configured to generate a sense signal indicative of temperature in a battery pack when the sensor is activated. The primary protection circuit is configured to generate a synchronizing signal in a first state or a second state, sample the sense signal when the synchronizing signal is in the first state, and provide primary protection to the battery pack based on the sense signal. A secondary protection circuit is configured to be controlled by the synchronizing signal, sample the sense signal when the synchronizing signal is in the second state, and provide secondary protection to the battery pack based on the sense signal. ## Claims ### Claim 1 A battery protection system comprising: a sensor configured to generate a sense signal indicative of a temperature in a battery pack when said sensor is activated; a primary protection circuit, coupled to said sensor, and configured to generate a synchronizing signal in one of a first state and a second state, sample said sense signal when said synchronizing signal is in said first state, and provide primary protection to said battery pack based on said sense signal when said synchronizing signal is in said first state; and a secondary protection circuit, coupled to said primary protection circuit and said sensor, and configured to be controlled by said synchronizing signal, sample said sense signal when said synchronizing signal is in said second state, and provide secondary protection to said battery pack based on said sense signal when said synchronizing signal is in said second state. ### Claim 2 (depends on 1) The battery protection system of claim 1, wherein when said synchronizing signal is in said second state, said secondary protection circuit is configured to activate said sensor at a preset frequency and sample said sense signal at said preset frequency; and wherein when said synchronizing signal is in said first state, said battery protection system is configured to maintain said sensor in an active condition to provide said sense signal to said primary protection circuit. ### Claim 3 (depends on 2) The battery protection system of claim 2, wherein said sensor comprises: a thermistor; and a resistor coupled to said thermistor, wherein said battery protection system is configured to activate said sensor by applying a preset voltage across said resistor and said thermistor, and wherein said sense signal comprises a voltage signal at a connection node of said resistor and said thermistor. ### Claim 4 (depends on 3) The battery protection system of claim 3, wherein when said synchronizing signal is in said second state: said primary protection circuit is configured to disconnect a first preset voltage from said sensor, and said secondary protection circuit is configured to connect a second preset voltage to said sensor at said preset frequency; and wherein when said synchronizing signal is in said first state: said primary protection circuit is configured to maintain connection of said first preset voltage to said sensor, and said secondary protection circuit is configured to disconnect said second preset voltage from said sensor. ### Claim 5 (depends on 3) The battery protection system of claim 3, wherein when said synchronizing signal is in said second state, said secondary protection circuit is configured to connect said preset voltage to said sensor at said preset frequency; and wherein when said synchronizing signal is in said first state, said secondary protection circuit is configured to maintain connection of said preset voltage to said sensor. ### Claim 6 (depends on 2) The battery protection system of claim 2, wherein said sensor comprises: a thermistor, wherein said battery protection system is configured to activate said thermistor by generating a preset current through said thermistor, and wherein said sense signal comprises a voltage on said thermistor. ### Claim 7 (depends on 6) The battery protection system of claim 6, wherein when said synchronizing signal is in said second state: said primary protection is configured to disable a first preset current, and said secondary protection circuit is configured to generate, at said preset frequency, a second preset current that flows through said thermistor; and wherein when said synchronizing signal is in said first state: said primary protection circuit is configured to maintain flow of said first preset current through said thermistor, and said secondary protection circuit is configured to disable said second preset current. ### Claim 8 (depends on 6) The battery protection system of claim 6, wherein when said synchronizing signal is said second state, said secondary protection circuit is configured to generate said preset current at said preset frequency; and wherein when said synchronizing signal is in said first state, said secondary protection circuit is configured to maintain flow of said preset current through said thermistor. ### Claim 9 A method for protecting a battery pack, said method comprising: activating a sensor to generate a sense signal indicative of a temperature in said battery pack; generating, using a primary protection circuit coupled to said sensor, a synchronizing signal in one of a first state and a second state to control a secondary protection circuit coupled to said primary protection circuit and said sensor; sampling, using said primary protection circuit, said sense signal when said synchronizing signal is in said first state; providing, using said primary protection circuit, primary protection to said battery pack based on said sense signal when said synchronizing signal is in said first state; sampling, using said secondary protection circuit, said sense signal when said synchronizing signal is in said second state; and providing, using said secondary protection circuit, secondary protection to said battery pack based on said sense signal when said synchronizing signal is in said second state. ### Claim 10 (depends on 9) The method of claim 9, further comprising: activating, using said secondary protection circuit, said sensor at a preset frequency when said synchronizing signal is in said second state; sampling, using said secondary protection circuit, said sense signal at said preset frequency when said synchronizing signal is in said second state; and maintaining said sensor in an active condition to provide said sense signal to said primary protection circuit when said synchronizing signal is in said first state. ### Claim 11 (depends on 10) The method of claim 10, wherein said sensor comprises a thermistor and resistor coupled to said thermistor, and wherein said method further comprises: activating said sensor by applying a preset voltage across said resistor and said thermistor, wherein said sense signal comprises a voltage signal at a connection node of said resistor and said thermistor. ### Claim 12 (depends on 11) The method of claim 11, further comprising: disconnecting, using said primary protection circuit, a first preset voltage from said sensor when said synchronizing signal is in said second state; connecting, using said secondary protection circuit, a second preset voltage to said sensor at said preset frequency when said synchronizing signal is in said second state; maintaining, using said primary protection circuit, connection of said first preset voltage to said sensor when said synchronizing signal is in said first state; and disconnecting, using said secondary protection circuit, said second preset voltage from said sensor when said synchronizing signal is in said first state. ### Claim 13 (depends on 11) The method of claim 11, further comprising: connecting, using said secondary protection circuit, said preset voltage to said sensor at said preset frequency when said synchronizing signal is in said second state; and maintaining, using said secondary protection circuit, connection of said preset voltage to said sensor when said synchronizing signal is in said first state. ### Claim 14 (depends on 10) The method of claim 10, wherein said sensor comprises a thermistor, and wherein said method further comprises: activating said thermistor by generating a preset current through said thermistor, wherein said sense signal comprises a voltage on said thermistor. ### Claim 15 (depends on 14) The method of claim 14, further comprising: disabling, using said primary protection circuit, a first preset current when said synchronizing signal is in said second state; generating, using said secondary protection circuit, a second preset current at said preset frequency through said thermistor when said synchronizing signal is in said second state; maintaining, using said primary protection circuit, said first preset current through said thermistor when said synchronizing signal is in said first state; and disabling, using said secondary protection circuit, said second preset current when said synchronizing signal is in said first state. ### Claim 16 (depends on 14) The method of claim 14, further comprising: generating, using said secondary protection circuit, said preset current at said preset frequency when said synchronizing signal is said second state; and maintaining, using said secondary protection circuit, said preset current through said thermistor when said synchronizing signal is in said first state. ### Claim 17 A battery pack comprising: a plurality of battery cells; and a battery protection system coupled to said battery cells, wherein said battery protection system comprises: a sensor configured to generate a sense signal indicative of temperature in said battery pack when said sensor is activated; a primary protection circuit, coupled to said sensor, and configured to generate a synchronizing signal in one of a first state and a second state, sample said sense signal when said synchronizing signal is in said first state, and provide primary protection to said battery pack based on said sense signal when said synchronizing signal is in said first state; and a secondary protection circuit, coupled to said primary protection circuit and said sensor, and configured to be controlled by said synchronizing signal, sample said sense signal when said synchronizing signal is in said second state, and provide secondary protection to said battery pack based on said sense signal when said synchronizing signal is in said second state. ### Claim 18 (depends on 17) The battery pack of claim 17, wherein when said synchronizing signal is in said second state, said secondary protection circuit is configured to activate said sensor at a preset frequency and sample said sense signal at said preset frequency; and wherein when said synchronizing signal is in said first state, said battery protection system is configured maintain said sensor in an active condition to provide said sense signal to said primary protection circuit. ### Claim 19 (depends on 18) The battery pack of claim 18, wherein said sensor comprises: a thermistor; and a resistor coupled to said thermistor, wherein said battery protection system is configured to activate said sensor by applying a preset voltage across said resistor and said thermistor, and wherein said sense signal comprises a voltage signal at a connection node of said resistor and said thermistor. ### Claim 20 (depends on 18) The battery pack of claim 18, wherein said sensor comprises: a thermistor, wherein said battery protection system is configured to activate said thermistor by generating a preset current that flows through said thermistor, and wherein said sense signal comprises a voltage on said thermistor.