# US 2016/0252583 A1 · Apparatus for estimating state of hybrid secondary battery and method thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2016/0252583 A1 - Document ID: US20160252583A1 - Status: Published application - Kind: A1 - Application number: 15/028,974 - Filed: 2014-10-14 - Published: 2016-09-01 - Earliest claimed: 2013-10-14 - Assignees: LG Chem, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Won-Tae JOE - Web page: https://patentgrep.com/patent/US20160252583A1 ## CPC - G01R 31/367: Software therefor, e.g. for battery testing using modelling or look-up tables - G01R 31/3842: combining voltage and current measurements - G01R 31/389: Measuring internal impedance, internal conductance or related variables - 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 16/00: Structural combinations of different types of electrochemical generators - Y02E 60/10: Energy storage using batteries - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - 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 An apparatus for estimating state of a hybrid secondary battery including a first secondary battery and a second secondary battery having different electrochemical characteristics from each other and being connected in parallel with each other, is provided. The apparatus includes a sensor unit which measures an operating voltage and an operating current of the secondary battery at time intervals, and a control unit which is electrically connected with the sensor unit and estimates the state of the hybrid secondary battery including at least one of a first state of charge of the first secondary battery and a second state of charge of the second secondary battery, by implementing an Extended Kalman Filter algorithm using a state equation and an output equation, in which the state equation includes, as a state parameter, at least one of the first state of charge of the first secondary battery and the second state of charge of the second secondary battery, and the output equation includes, as an output parameter, the operating voltage of the hybrid secondary battery. ## Claims ### Claim 1 An apparatus for estimating state of a hybrid secondary battery, wherein the hybrid secondary battery comprises a first secondary battery and a second secondary battery having different electrochemical characteristics from each other and being connected in parallel with each other, the apparatus comprising: a sensor unit configured to measure, at time intervals, an operating voltage and an operating current of the secondary battery; and a control unit electrically connected with the sensor unit, and configured to estimate the state of the hybrid secondary battery, wherein the state comprises at least one of a first state of charge of the first secondary battery and a second state of charge of the second secondary battery, by implementing an Extended Kalman Filter algorithm using a state equation and an output equation, wherein the state equation comprises, as a state parameter, at least one of the first state of charge of the first secondary battery and the second state of charge of the second secondary battery, and the output equation comprises, as an output parameter, the operating voltage of the hybrid secondary battery, wherein the state equation and the output equation are derived from a first circuit unit and a second circuit unit which correspond to the first secondary battery and the second secondary battery, respectively, and connected in parallel with each other, and at least one of the first circuit unit and the second circuit unit comprises an open-circuit voltage element varying voltage according to a state of charge of a corresponding secondary battery, and optionally, an impedance element varying voltage according to current flowing through a corresponding circuit unit. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the state parameter further includes at least one of a voltage formed by the impedance element included in the first circuit unit; and a voltage formed by the impedance element included in the second circuit unit. ### Claim 3 (depends on 1) The apparatus of claim 1, wherein the state equation includes, as an input parameter, a first current flowing through the first circuit unit, and a second current flowing through the second circuit unit, and the control unit determines the first current and the second current, by using a current distribution equation derived from the circuit model, and the current measured by the sensor unit. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the output equation is derived from voltage analysis of the circuit model, and includes a plurality of input parameters, and the plurality of input parameters include: a current measured by the sensor unit; an open-circuit voltage of the first circuit unit; an open-circuit voltage of the second circuit unit; optionally, an impedance voltage of the first circuit unit; and optionally, an impedance voltage of the second circuit unit. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the state equation is defined such that the first state of charge and the second state of charge are determined by adding up currents flowing through the first circuit unit and the second circuit unit according to time, respectively, and the control unit time-updates the first state of charge and the second state of charge, by implementing [state estimate time update] of the Extended Kalman Filter algorithm, by using the state equation. ### Claim 6 (depends on 2) The apparatus of claim 2, wherein the state equation is defined such that the voltage formed by the impedance element varies according to time, by an impedance voltage formula derived from circuit analysis of the impedance element included in the first circuit unit and the second circuit unit, respectively, and the control unit time-updates the voltage formed by each impedance element, by implementing [state estimate time update] of the Extended Kalman Filter algorithm, by using the state equation. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the control unit implements [error covariance time update] of the Extended Kalman Filter algorithm, by using Jacobian matrix derived from the state equation. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the control unit estimates the operating voltage of the hybrid secondary battery, by implementing [output estimate] of the Extended Kalman Filter algorithm, by using the output equation. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the control unit implements [Kalman gain determination] of the Extended Kalman Filter algorithm, by using Jacobian matrix derived from the output equation and the time-updated error covariance. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the control unit implements [state estimate measurement update] of the Extended Kalman Filter algorithm, by reflecting the determined Kalman gain to a difference between the measured operating voltage and the estimated operating voltage. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the control unit implements [error covariance measurement update] of the Extended Kalman Filter algorithm, by using the time-updated error covariance and the determined Kalman gain. ### Claim 12 (depends on 1) The apparatus of claim 1, wherein the state equation includes a process noise, and the output equation includes a sensor noise. ### Claim 13 (depends on 1) The apparatus of claim 1, wherein the control unit estimates the state of charge of the hybrid secondary battery, by using the first state of charge and the second state of charge. ### Claim 14 (depends on 1) The apparatus of claim 1, wherein the impedance element included in the first circuit unit or the second circuit unit includes at least one resistor, at least one capacitor, at least one inductor or a combination thereof. ### Claim 15 (depends on 14) The apparatus of claim 14, wherein the impedance element includes at least one RC circuit in which a resistor and a capacitor are connected in parallel, and optionally, a resistor connected in series with the same. ### Claim 16 (depends on 1) The apparatus of claim 1, wherein the open-circuit voltage element and the impedance element are connected in series. ### Claim 17 A method for estimating state of a hybrid secondary battery, wherein the hybrid secondary battery comprises a first secondary battery and a second secondary battery having different electrochemical characteristics from each other and being connected in parallel with each other, the method comprising: measuring, at time intervals, an operating voltage and an operating current of the hybrid secondary battery; and estimating the state of the hybrid secondary battery, wherein the state comprises at least one of a first state of charge of the first secondary battery and a second state of charge of the second secondary battery, by implementing an Extended Kalman Filter algorithm using a state equation and an output equation, wherein the state equation comprises, as a state parameter, at least one of the first state of charge of the first secondary battery and the second state of charge of the second secondary battery, and the output equation comprises, as an output parameter, the operating voltage of the hybrid secondary battery, wherein the state equation and the output equation are derived from a circuit model, and the circuit model comprises a first circuit unit comprising an open-circuit voltage element corresponding to the first secondary battery, and optionally, an impedance element corresponding to the first secondary battery, and a second circuit unit connected in parallel with the first circuit unit, and comprising an open-circuit voltage element corresponding to the second secondary battery, and optionally, an impedance element corresponding to the second secondary battery. ### Claim 18 (depends on 17) The method of claim 17, further including estimating the state of charge of the hybrid secondary battery, by using the first state of charge and the second state of charge. ### Claim 19 (depends on 18) The method of claim 18, further including storing, transmitting, or displaying the estimated state of charge of the hybrid secondary battery. ### Claim 20 (depends on 18) The method of claim 18, wherein the Extended Kalman Filter algorithm includes: state estimate time update; error covariance time update; output estimation; Kalman gain determination; state estimate measurement update; and error covariance measurement update. ### Claim 21 (depends on 1) An electrically-driven apparatus comprising the apparatus as defined in claim 1. ### Claim 22 (depends on 17) A computer-readable recording medium recording therein a program for implementing the method as defined in claim 17.