# US 7,609,031 B2 · Method for balancing lithium secondary cells and modules > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,609,031 B2 - Document ID: US7609031B2 - Status: Granted - Kind: B2 - Application number: 12/195,274 - Filed: 2008-08-20 - Published: 2008-12-18 - Granted: 2009-10-27 - Earliest claimed: 2005-12-02 - Assignees: Southwest Electronic Energy Corporation - Inventors: Claude Leonard Benckenstein; David Allen White - Web page: https://patentgrep.com/patent/US7609031B2 ## CPC - H02J 7/54: Passive balancing, e.g. using resistors or parallel MOSFETs - H01M 10/441: {for several batteries or cells simultaneously or sequentially} - H01M 10/482: {for several batteries or cells simultaneously or sequentially} - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/486: {for measuring temperature} - H01M 2010/4271: {Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing} - H02J 7/50: acting upon multiple batteries simultaneously or sequentially - Y02E 60/10: Energy storage using batteries - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - 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 pack control module for balancing a plurality of lithium secondary cells or groups of lithium secondary cells connected in series and method of use. ## Claims ### Claim 1 A battery pack control module for balancing a plurality of lithium secondary cells or groups of lithium secondary cells connected in series, wherein the battery pack control module comprises: a controller assembly; a disconnect circuit comprising a charge switch and a discharge switch, wherein the disconnect circuit engages the controller assembly and the plurality of lithium secondary cells or groups of lithium secondary cells connected in series; a pack sensing circuit connected to the controller assembly and the plurality of lithium secondary cells or groups of lithium secondary cells connected in series, wherein the pack sensing circuit comprises: a temperature measuring device; a current measuring device; and a cell voltage measuring device; at least one balancing circuit connected between the plurality of lithium secondary cells or groups of lithium secondary cells connected in series and the controller assembly, wherein each balancing circuit comprises: a shunt resistor connected to a bypass switch; a power source for charging the plurality of lithium secondary cells or groups of lithium secondary cells further connected to the controller assembly; a current limiting resistor connected to the power source for limiting current from the plurality of lithium secondary cells or groups of lithium secondary cells connected in series while charging; at least one configuration table containing cell specifications of the lithium secondary cells disposed in configuration memory connected to the controller assembly; a protective diode connected to the plurality of lithium secondary cells or groups of lithium secondary cells connected in series and to the at least one disconnect circuit, and the protective diode prevents excessive voltage from developing across the controller assembly; computer instructions within the controller assembly for instructing the controller assembly to monitor the state of charge for the plurality of lithium secondary cells or groups of lithium secondary cells connected in series; computer instructions within the controller assembly for instructing the controller assembly to control the disconnect circuit in conjunction with control of the balancing circuit and apply voltage from the power source to the charge switch or discharge switch from a lithium secondary cell or groups of lithium secondary cells when a predetermined state of charge has not been reached or is exceeded; and computer instructions within the controller assembly for instructing the controller assembly to measure the state of charge for each lithium secondary cells after each application of voltage and if a predetermined state of charge is reached for each lithium secondary cell actuate at least a partial discharge of one or more lithium secondary cells simultaneously, enabling simultaneous discharge of one or more lithium secondary cells while one or more lithium secondary cells is charging, discharging, quiescent, or is in storage. ### Claim 2 (depends on 1) The module of claim 1, wherein the controller assembly comprises an analog controller and a digital controller. ### Claim 3 (depends on 2) The module of claim 2, the digital controller comprises at least one processor. ### Claim 4 (depends on 1) The module of claim 1, wherein the protective diode is a reverse voltage protection diode or a bypass diode. ### Claim 5 (depends on 1) The module of claim 1, further comprising a second diode for balancing the plurality of lithium secondary cells or groups of lithium secondary cells by discharging at least one lithium secondary cell or group of lithium secondary cells or charging at least one lithium secondary cell or group of lithium secondary cells until a balance phase for the connected cells is achieved. ### Claim 6 (depends on 1) The module of claim 1, wherein the configuration memory with cell specifications further comprises computer instructions for instructing the processor to customize cell specifications of the battery pack control module using the cell specifications. ### Claim 7 (depends on 1) The module of claim 1, further comprising a display device in communication with the controller assembly, and wherein the controller assembly further comprises computer instructions for instructing the processor to display the state of charge for each cell on the display device. ### Claim 8 (depends on 7) The module of claim 7, wherein the display device comprises a member of the group consisting of: a plurality of light emitting diodes, a liquid crystal display, a plasma display, and combinations thereof. ### Claim 9 (depends on 1) The module of claim 1, wherein the controller assembly further comprises computer instructions for instructing the processor to display an absolute state of charge by counting coulombs. ### Claim 10 (depends on 1) The module of claim 1, wherein the power source comprises a rechargeable battery, a fuel cell, a solar panel, a hydroelectric source or other electric power supply. ### Claim 11 (depends on 1) The module of claim 1, wherein the power source is at least one capacitor, at least one supercapacitor, at least one other electrochemical cell, or combinations. ### Claim 12 (depends on 4) The module of claim 4, wherein the protective diode is a zener diode connected in series with a current limiting resistor, and wherein the zener diode is disposed between a high charge lithium secondary cell or group of lithium secondary cells and a different charge lithium secondary cell or group of lithium secondary cells, and wherein the zener diode is actuatable by the disconnect circuit. ### Claim 13 (depends on 1) The module of claim 1 wherein the by-pass switch comprises a member selected from the group consisting of: a semiconductor switch, a variable resistor, a mini-micro switch or combinations thereof. ### Claim 14 (depends on 1) The module of claim 1, wherein cell voltage measuring device measures voltage between lithium secondary cells, between groups of lithium secondary cells, or combinations thereof. ### Claim 15 (depends on 1) The module of claim 1, wherein the temperature measuring device, the current measuring device or both are external to the controller assembly. ### Claim 16 (depends on 2) The module of claim 2, wherein the digital controller comprises one or more analog I/O ports, one or more digital I/O ports, and memory with processing logic. ### Claim 17 (depends on 1) The module of claim 1, wherein the computer instructions for controlling the controller assembly include instructions to direct the processor to connect the plurality of lithium secondary cells or groups of lithium secondary cells connected in series to the power supply, to connect the plurality of lithium secondary cells or groups of lithium secondary cells connected in series to a load, or to disconnect the plurality of lithium secondary cells or groups of lithium secondary cells from a load, or combinations thereof. ### Claim 18 (depends on 1) The module of claim 1, further comprising a voltage regulator for powering the controller assembly. ### Claim 19 A method for extending power duration for lithium secondary cells or groups of lithium secondary cells connected in series, or connected in parallel and then in series, comprising the steps of: monitoring and measuring parameters for lithium secondary cells or groups of lithium secondary cells connected in parallel, or are further connected in series, to determine a state of charge for the lithium secondary cells or groups of lithium secondary cells; limiting current from the plurality of lithium secondary cells or groups of lithium secondary cells connected in parallel, or are further connected in series, to determine a state of charge for lithium secondary cells or groups of lithium secondary cells; using protective diode connected to the plurality of lithium secondary cells or groups of lithium secondary cells connected in series and to the at least one disconnect circuit, and the protective diode prevents excessive voltage from developing across the controller assembly; removing at least a portion of a charge from at least one of the lithium secondary cells or groups of lithium secondary cells to achieve a balanced state of charge for the lithium secondary cells connected in series, or groups of lithium secondary cells connected in series, in a discharge phase, a charge phase, a quiescent phase, and a storage phase using a digital controller to execute computer instructions, wherein the computer instructions instruct a processor comprise the steps of: monitor the state of charge for the lithium secondary cells or groups of lithium secondary cells; control a disconnect circuit connected to a controller assembly while controlling a balancing circuit connected to the lithium secondary cells or groups of lithium secondary cells to apply voltage from a power source to a charge switch that is part of the disconnect circuit; or discharge voltage from a lithium secondary cell or groups of lithium secondary cells when a predetermined state of charge has not been reach or a predetermined state of charge has been exceeded; and measure a state of charge for each lithium secondary cell or groups of lithium secondary cells after each application of voltage and prevent application of voltage and if a predetermined state of charge is reached for each cell or groups of cells enabling at least partial discharge of one or more lithium secondary cells or groups of lithium secondary cell simultaneously while one or more lithium secondary cells or groups of lithium secondary cells is charging. ### Claim 20 (depends on 19) The method of claim 19, wherein the monitoring and measuring further comprises measuring temperature of lithium secondary cells or groups of lithium secondary cells, measuring current of lithium secondary cells or groups of lithium secondary cells, measuring cell voltages of lithium secondary cells or groups of lithium secondary cells, or combinations thereof. ### Claim 21 (depends on 19) The method of claim 19, further comprising using a configuration table to customize the balancing of the state of charge for the lithium secondary cells or groups of lithium secondary cells, or combinations thereof. ### Claim 22 (depends on 19) The method of claim 19, further comprising the step of connecting the plurality of lithium secondary cells or groups of lithium secondary cells together in series to form at least one battery pack system. ### Claim 23 (depends on 19) The method of claim 19, farther comprising the step of preventing excessive voltage from developing across the lithium secondary cells or groups of lithium secondary cells. ### Claim 24 (depends on 19) The method of claim 19, wherein the step of removing a portion of the charge for at least one lithium secondary cell or at least one group of lithium secondary cells until the balance state uses a disconnect circuit and a diode. ### Claim 25 (depends on 19) The method of claim 19, further comprising using a diode to protect the circuit between the cells.