# US 11,299,063 B2 · Method and apparatus for controlling electric power flow 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 11,299,063 B2 - Document ID: US11299063B2 - Status: Granted - Kind: B2 - Application number: 16/788,850 - Filed: 2020-02-12 - Published: 2021-08-12 - Granted: 2022-04-12 - Earliest claimed: 2020-02-12 - Assignees: GM Global Technology Operations LLC - Applicants: GM Global Technology Operations LLC - Inventors: Yue-Yun Wang; Andres V. Mituta; Garrett M. Seeman; Justin Bunnell - Web page: https://patentgrep.com/patent/US11299063B2 ## CPC - B60L 58/14: Preventing excessive discharging - B60L 58/21: having the same nominal voltage - B60L 58/22: Balancing the charge of battery modules - G01R 31/382: Arrangements for monitoring battery or accumulator variables, e.g. SoC - H02J 7/14: for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle - H02J 7/50: acting upon multiple batteries simultaneously or sequentially - H02J 7/62: against overcurrent - H02J 7/63: against overdischarge - H02J 7/65: against overtemperature - H02J 7/663: {using battery or load disconnect circuits (H02J9/002 takes precedence)} - H02J 7/855: {with circuits adapted for supplying loads from the battery} - H02J 7/975: {in response to temperature} - B60L 2240/545: Temperature - H02J 2105/37: exchanging power with electric vehicles [EV] or with hybrid electric vehicles [HEV] - Y02E 60/10: Energy storage using batteries - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - 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 - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A battery system is electrically connected to a power bus that is arranged to supply electric power to an on-vehicle actuator such as an electric traction machine. Controlling electric power flow in the battery pack includes determining states of charge for the plurality of battery packs, identifying one of the battery packs as a weakest battery pack based upon the states of charge, and determining an internal circulating current being transferred via the wiring harness that is associated with charging of the weakest battery pack. Electric power transfer through the wiring harness and the power bus is controlled such that the internal circulating current is less than an internal circulating current limit. In one embodiment, the internal circulating current limit is determined in relation to battery temperature. ## Claims ### Claim 1 A method for controlling electric power flow in a battery system for a vehicle, wherein the battery system includes a plurality of battery packs that are electrically connected via a wiring harness, and wherein the battery packs are electrically connected via the wiring harness to a power bus, the method comprising: monitoring, via a plurality of sensors, parameters associated with the plurality of battery packs; determining states of charge and impedances for the plurality of battery packs; determining an internal circulating current that is being transferred between the plurality of battery packs via the wiring harness based upon the states of charge; and controlling electric power transfer through the wiring harness by introducing a resistive load onto the power bus such that the internal circulating current is less than an internal circulating current limit. ### Claim 2 (depends on 1) The method of claim 1, wherein controlling the electric power transfer through the wiring harness such that the internal circulating current is less than the internal circulating current limit comprises: identifying one of the battery packs as a weakest battery pack based upon the states of charge and the impedances of the battery packs; determining the internal circulating current being transferred to the weakest battery pack via the wiring harness; and disconnecting the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit. ### Claim 3 (depends on 2) The method of claim 2, further comprising determining that the vehicle is in a key-off state; and disconnecting the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit and the vehicle is in the key-off state. ### Claim 4 (depends on 1) The method of claim 1, wherein controlling electric power transfer through the wiring harness such that the internal circulating current is less than the internal circulating current limit comprises: executing feed-forward control based upon the states of charge and the impedances for the plurality of battery packs to determine a first load current; executing feedback control based upon the internal circulating current and the internal circulating current limit to determine a current feedback term; determining a bias load current based upon the first load current and the current feedback term; and controlling operation of an electrically-powered accessory device to control the internal circulating current based upon the bias load current. ### Claim 5 (depends on 4) The method of claim 4, wherein controlling electric power transfer through the wiring harness such that the internal circulating current is less than the internal circulating current limit comprises introducing the resistive load as the bias load current onto the power bus to control the internal circulating current to be less than the internal circulating current limit. ### Claim 6 (depends on 1) The method of claim 1, further comprising an electric machine being electrically connected to the power bus; the method further comprising: monitoring electric load demand being delivered to the electric machine; identifying one of the battery packs as a strongest battery pack based upon the states of charge and the impedances of the battery packs; and decreasing the electric load demand being delivered to the electric machine to control the electric power transfer through the wiring harness such that the discharge current of the strongest pack is less than a discharge current limit. ### Claim 7 A method for controlling electric power flow in a battery system for a vehicle, wherein the battery system includes a plurality of lithium-ion battery packs that are electrically connected via a wiring harness, and wherein the battery system is electrically connected via the wiring harness to a power bus, the method comprising: monitoring, via a plurality of sensors, parameters associated with the plurality of battery packs; determining states of charge and impedances for the plurality of lithium-ion battery packs; determining an internal circulating current being transferred via the wiring harness; and controlling electric power transfer through the wiring harness and the power bus by introducing a resistive load onto the power bus such that the internal circulating current is less than an internal circulating current limit. ### Claim 8 (depends on 7) The method of claim 7, wherein controlling electric power transfer through the wiring harness and the power bus such that the internal circulating current is less than an internal circulating current limit comprises: identifying one of the battery packs as a weakest battery pack based upon the states of charge; determining the internal circulating current being transferred to the weakest battery pack via the wiring harness; and disconnecting the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit. ### Claim 9 (depends on 8) The method of claim 8, further comprising disconnecting the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit and when the vehicle is in a key-off state. ### Claim 10 (depends on 7) The method of claim 7, wherein controlling electric power transfer through the wiring harness and the power bus such that the internal circulating current is less than the internal circulating current limit comprises: executing feed-forward control based upon the states of charge and the impedances for the lithium-ion battery packs to determine a first load current; executing feedback control based upon the internal circulating current and the internal circulating current limit to determine a current feedback term; determining a bias load current based upon the first load current and the current feedback term; and controlling operation of an electrically-powered accessory device to control the internal circulating current based upon the bias load current. ### Claim 11 (depends on 10) The method of claim 10, wherein controlling electric power transfer through the wiring harness such that the internal circulating current is less than the internal circulating current limit comprises introducing the resistive load as the bias load current onto the power bus to control the internal circulating current to be less than the internal circulating current limit. ### Claim 12 An electric power system for a vehicle, comprising: a battery system including plurality of battery packs, a plurality of sensors arranged to monitor the battery packs, a high-voltage DC power bus, a plurality of switches interposed between the plurality of battery packs and the power bus, an electric machine, a wiring harness, and a controller; wherein the plurality of battery packs are electrically connected via the wiring harness; wherein the plurality of battery packs are electrically connected via the wiring harness to the power bus; wherein the controller is in communication with the plurality of sensors, the plurality of switches, and the electric machine; wherein the controller includes an instruction set, wherein the instruction set is executable to: monitor, via the plurality of sensors, parameters associated with the plurality of battery packs, determine states of charge and impedances for the plurality of battery packs, determine an internal circulating current that is being transferred between the plurality of battery packs via the wiring harness based upon the states of charge and the impedances of the battery packs, and control electric power transfer through the wiring harness and the power bus by introducing a resistive load onto the power bus such that the internal circulating current is less than an internal circulating current limit. ### Claim 13 (depends on 12) The electric power system of claim 12, wherein the instruction set being executable to control electric power transfer through the wiring harness and the power bus such that the internal circulating current is less than the internal circulating current limit comprises the instruction set being executable to: identify one of the battery packs as a weakest battery pack based upon the states of charge, determine the internal circulating current being transferred to the weakest battery pack via the wiring harness, and disconnect the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit. ### Claim 14 (depends on 13) The electric power system of claim 13, further comprising the instruction set being executable to determine that the vehicle is in a key-off state; and disconnect the weakest battery pack from the wiring harness when the internal circulating current is greater than the internal circulating current limit and the vehicle is in the key-off state. ### Claim 15 (depends on 12) The electric power system of claim 12, wherein the instruction set being executable to control the electric power transfer through the wiring harness and the power bus such that the internal circulating current is less than the internal circulating current limit comprises the instruction set being executable to control operation of an electrically-powered accessory device to control the internal circulating current to be less than the internal circulating current limit. ### Claim 16 (depends on 12) The electric power system of claim 12, wherein the instruction set being executable to control electric power transfer through the wiring harness such that the internal circulating current is less than the internal circulating current limit comprises the instruction set being executable to: execute a feed-forward control routine based upon the states of charge and the impedances for the plurality of battery packs to determine a first load current; execute a feedback control routine based upon the internal circulating current and the internal circulating current limit to determine a current feedback term; determine a bias load current based upon the first load current and the current feedback term; and control operation of an electrically-powered accessory device to control the internal circulating current based upon the bias load current.