# US 2014/0152317 A1 · Systems and methods to protect against over-discharge in a battery system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152317 A1 - Document ID: US20140152317A1 - Status: Published application - Kind: A1 - Application number: 13/690,886 - Filed: 2012-11-30 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: ROBERT C. BARASZU; KURT M. JOHNSON; ZACHARY D. BYLSMA; DAMON R. FRISCH; WEI LIU; DAVID S. MAXWELL - Web page: https://patentgrep.com/patent/US20140152317A1 ## CPC - G01N 27/416: Systems (G01N27/27 takes precedence) - 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 10/482: {for several batteries or cells simultaneously or sequentially} - H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane - Y02E 60/10: Energy storage using batteries - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - 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 system may include a plurality of subdivisions, such as battery cells or sub-packs. A measurement system configured to determine a subdivision electrical parameter associated with each of a plurality of subdivisions. A battery control may identify a subdivision satisfying a criterion based on the plurality of subdivision electrical parameters. According to some embodiments, the battery control system may determine a ratio of the subdivision electrical parameter of the identified subdivision to the electrical parameter of the battery pack. The ratio may be used to scale the electrical parameter associated with the battery pack by the ratio. According to other embodiments, the subdivision electrical parameter associated with the identified subdivision may be provided to a battery state estimation system. The scaled electrical parameter or the electrical parameter associated with the identified subdivision may be used by a battery state estimation system to generate an estimated battery state. ## Claims ### Claim 1 A system comprising: a battery pack comprising a plurality of subdivisions; a measurement system configured to determine a plurality of subdivision electrical parameters, each subdivision electrical parameter of the plurality of electrical parameters being associated with one of the plurality of subdivisions, and to determine a pack electrical parameter associated with the battery pack; a battery control system communicatively coupled to the measurement system, the battery control system configured to identify a subdivision satisfying a criterion based on the plurality of subdivision electrical parameters and generate an adjusted pack electrical parameter based on the electrical parameter of the identified subdivision and the pack electrical parameter; and a battery state estimation system in communication with the battery control system, the battery state estimation system configured to generate an estimated battery state based on the adjusted pack electrical parameter. ### Claim 2 (depends on 1) The system of claim 1, wherein the battery control system is further configured to determine a ratio of the subdivision electrical parameter of the identified subdivision and the pack electrical parameter, and to scale the pack electrical parameter by the ratio to generate the adjusted pack electrical parameter. ### Claim 3 (depends on 1) The system of claim 1, wherein the battery control system is further configured to measure a time delay between one of a maximum value and a minimum value of the subdivision electrical parameter of the identified subdivision and a corresponding maximum or minimum value of the pack electrical parameter, to provide the time delay to the battery state estimation system; and wherein the battery state estimation system is further configured to generate the estimate of the voltage of the battery pack based on the time delay. ### Claim 4 (depends on 1) The system of claim 1, wherein each of the plurality of subdivisions is individually replaceable, and wherein the battery pack comprises at least one replacement subdivision. ### Claim 5 (depends on 1) The system of claim 1, wherein the battery control system is configured to identify one of a lowest capacity subdivision, a lowest voltage subdivision, and a lowest current subdivision based on the criterion. ### Claim 6 (depends on 1) The system of claim 1, wherein the measurement system further comprises a plurality of voltage measurement sensors, and the subdivision electrical parameter comprises a voltage associated with each of the plurality of subdivisions. ### Claim 7 (depends on 1) The system of claim 1, wherein the estimated battery state comprises a state of charge of the identified subdivision, and the battery control system is further configured to restrict discharge from the battery pack when the estimated state of charge falls below an over-depletion threshold. ### Claim 8 (depends on 1) The system of claim 1, wherein each of the plurality of subdivisions comprises one or more battery cells. ### Claim 9 (depends on 1) The system of claim 1, wherein each of the plurality of subdivisions comprises one or more battery sub-packs, and each of the one or more battery-sub packs comprises one or more battery cells. ### Claim 10 A method of estimating the voltage of a battery pack comprising a plurality of subdivisions, the method comprising: determining a plurality of subdivision electrical parameters, each subdivision electrical parameter of the plurality of electrical parameters being associated with one of the plurality of subdivisions; identifying a subdivision satisfying a criterion based on the plurality of subdivision electrical parameters; determining a pack electrical parameter associated with the battery pack; generating an adjusted pack electrical parameter based on the subdivision electrical parameter of the identified subdivision and the pack electrical parameter; providing the adjusted pack electrical parameter to a battery state estimation system; and generating an estimated battery state based on the adjusted pack electrical parameter. ### Claim 11 (depends on 10) The method of claim 10, further comprising: determining a ratio of the subdivision electrical parameter of the identified subdivision and the pack electrical parameter; and scaling the pack electrical parameter by the ratio to generate the adjusted pack electrical parameter. ### Claim 12 (depends on 10) The method of claim 10, further comprising: measuring a time delay between a one of a maximum value and a minimum value of the subdivision electrical parameter of the identified subdivision and a corresponding maximum or minimum value of the pack electrical parameter; and providing the time delay to the battery state estimation system; wherein generating the estimated battery state is further based on the time delay. ### Claim 13 (depends on 10) The method of claim 10, wherein each of the plurality of subdivisions is individually replaceable, and wherein the battery pack comprises at least one replacement subdivision. ### Claim 14 (depends on 10) The method of claim 10, wherein identifying the subdivision satisfying the criterion comprises identifying one of a lowest capacity subdivision, a highest electrical resistance, a lowest voltage subdivision, and a lowest current subdivision. ### Claim 15 (depends on 10) The method of claim 10, wherein the subdivision electrical parameter comprises a subdivision voltage and the adjusted pack electrical parameter comprises an average voltage. ### Claim 16 (depends on 10) The method of claim 10, wherein the estimated battery state comprises an estimated state of charge. ### Claim 17 (depends on 16) The method of claim 16, further comprising restricting discharge from the battery pack when the estimated state of charge falls below a threshold. ### Claim 18 (depends on 10) The method of claim 10, wherein each of the plurality of subdivisions comprises one or more battery cells. ### Claim 19 (depends on 10) The method of claim 10, wherein each of the plurality of subdivisions comprises one or more battery sub-packs, and each of the one or more battery-sub packs comprises one or more battery cells. ### Claim 20 A method of estimating the voltage of battery pack comprising a plurality of subdivisions, the method comprising: determining a plurality of subdivision electrical parameters, each subdivision electrical parameter of the plurality of electrical parameters being associated with one of the plurality of subdivisions; identifying a subdivision satisfying a criterion based on the plurality of subdivision electrical parameters; providing the electrical parameter of the identified subdivision a battery state estimation system; generating an estimated state of charge based on the electrical parameter of the identified subdivision; and restricting discharge from the battery pack when the estimated state of charge falls below a threshold.