# US 2021/0281084 A1 · Battery module-level balancing of portable power supply > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0281084 A1 - Document ID: US20210281084A1 - Status: Published application - Kind: A1 - Application number: 17/190,158 - Filed: 2021-03-02 - Published: 2021-09-09 - Earliest claimed: 2020-03-05 - Applicants: Milwaukee Electric Tool Corporation - Inventors: Chun Jian Tang; Benjamin C. Tesch; Chien-Chih Chao; Brian M. Hockers - Web page: https://patentgrep.com/patent/US20210281084A1 ## CPC - H02J 7/52: for charge balancing, e.g. equalisation of charge between batteries - H02J 7/54: Passive balancing, e.g. using resistors or parallel MOSFETs - H02J 7/96: in response to battery voltage - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY ## Abstract A portable power supply including a first subcore including a first plurality of battery cells, a second subcore including a second plurality battery cells and electrically connected in series with the first subcore, and a controller including an electronic processor. The controller is configured to receive a first voltage value indicative of a voltage of the first plurality of battery cells from the first subcore and a second voltage value indicative of a voltage of the second plurality of battery cells from the second subcore. The controller is further configured to determine a difference between the first voltage value and the second voltage value, compare the difference to a balance threshold, and perform a balancing operation when the difference is greater than or equal to the balance threshold. ## Claims ### Claim 1 A portable power supply comprising: a first subcore including a first plurality of battery cells; a second subcore including a second plurality battery cells and electrically connected in series with the first subcore; and a controller including an electronic processor configured to: receive a first voltage value indicative of a voltage of the first plurality of battery cells from the first subcore, receive a second voltage value indicative of a voltage of the second plurality of battery cells from the second subcore, determine a difference between the first voltage value and the second voltage value; compare the difference to a balance threshold; and perform a balancing operation when the difference is greater than or equal to the balance threshold. ### Claim 2 (depends on 1) The portable power supply of claim 1, wherein the controller is further configured to determine whether the first voltage value is greater than the second voltage value. ### Claim 3 (depends on 2) The portable power supply of claim 2, wherein the controller is further configured to: operate the first subcore in an active mode of operation when the first voltage value is greater than the second voltage value; determine whether the first voltage value has decreased to a termination threshold; and operate the first subcore in a normal mode of operation when the first voltage value has reached the termination threshold. ### Claim 4 (depends on 2) The portable power supply of claim 2, wherein the controller is further configured to: activate a first magnetic field source included in the first subcore when the first voltage value is greater than the second voltage value to enable current flow from the first plurality of battery cells to a load through a first reed switch that is closed when the first magnetic field source is activated; determine whether the first voltage value has decreased to a termination threshold; and deactivate the first magnetic field source when the first voltage value has reached the termination threshold. ### Claim 5 (depends on 2) The portable power supply of claim 2, wherein the controller is further configured to: energize a first relay coil included in the first subcore when the first voltage value is greater than the second voltage value to enable current flow from the first plurality of battery cells to a load through a first relay that is closed when the first relay coil is energized; determine whether the first voltage value has decreased to a termination threshold; and de-energize the first relay coil when the first voltage value has reached the termination threshold. ### Claim 6 (depends on 2) The portable power supply of claim 2, wherein the controller is further configured to: increase a temperature of a heating element included in the first subcore when the first voltage value is greater than the second voltage value to increase current flow from the first plurality of battery cells through a leakage device included in the first subcore; determine whether the first voltage value has decreased to a termination threshold; and decrease the temperature of the heating element when the first voltage value has reached the termination threshold. ### Claim 7 (depends on 2) The portable power supply of claim 2, wherein the controller is further configured to: control a battery front end device included in the first subcore when the first voltage value is greater than the second voltage value to enable current flow from the first plurality of battery cells to a load; determine whether the first voltage value has decreased to a termination threshold; and control the battery front end device included in the first subcore to disable current flow from the first plurality of battery cells when the first voltage value has reached the termination threshold. ### Claim 8 (depends on 7) The portable power supply of claim 7, wherein the load is electrically connected to an output pin of the battery front end device. ### Claim 9 A method of balancing subcore voltages in a portable power supply, the portable power supply includes a first subcore including a first plurality of battery cells, a second subcore including a second plurality of battery cells and electrically connected in series with the first subcore, and a controller including an electronic processor, the method comprising: receiving, using the controller, a first voltage value indicative of a voltage of the first plurality of battery cells from the first subcore; receiving, using the controller, a second voltage value indicative of a voltage of the second plurality of battery cells from the second subcore; determining, using the controller, a difference between the first voltage value and the second voltage value; comparing, using the controller, the difference to a balance threshold; and performing a balancing operation when the difference is greater than or equal to the balance threshold. ### Claim 10 (depends on 9) The method of claim 9, further comprising: determining, using the controller, whether the first voltage value is greater than the second voltage value. ### Claim 11 (depends on 10) The method of claim 10, further comprising: operating, using the controller, the first subcore in an active operation mode; determining, using the controller, whether the first voltage value has decreased to a termination threshold; and operating the first subcore in a normal operating mode when the first voltage value has reached the termination threshold. ### Claim 12 (depends on 10) The method of claim 10, further comprising: activating, using the controller, a first magnetic field source included in the first subcore; closing, using the first magnetic field source, a first reed switch included in the first subcore to enable current to flow from the plurality of battery cells to a first load included in the first subcore; determining, using the controller, whether the first voltage value has decreased to a termination threshold; and deactivating, using the controller, the first magnetic field source when the first voltage value has reached the termination threshold. ### Claim 13 (depends on 10) The method of claim 10, further comprising: energizing, using the controller, a first relay coil included in the first subcore; closing, using the first relay coil, a first relay included in the first subcore to enable current to flow from the plurality of battery cells to a first load included in the first subcore; determining, using the controller, whether the first voltage value has decreased to a termination threshold; and de-energizing, using the controller, the first relay coil when the first voltage value has reached the termination threshold. ### Claim 14 (depends on 10) The method of claim 10, further comprising: increasing, using the controller, temperature of a heating element included in the first subcore; increasing, using the heating element, temperature of a leakage device included in the first subcore to enable current flow from the first plurality of battery cells through the leakage device; determining, using the controller, whether the first voltage value has decreased to a termination threshold; and decreasing, using the controller, temperature of the heating element when the first voltage value has reached the termination threshold. ### Claim 15 (depends on 10) The method of claim 10, further comprising: enabling, using a battery front end device included in the first subcore, current flow from the first plurality of battery cells to a load; determining, using the controller, whether the first voltage value has decreased to a termination threshold; and disabling, using the battery front end device, current flow from the first plurality of battery cells when the first voltage value has reached the termination threshold. ### Claim 16 (depends on 15) The method of claim 15, wherein the load is electrically connected to an output pin of the battery front end device. ### Claim 17 A method of charging one or more subcores in a portable power supply, the portable power supply includes a first subcore including a first plurality of battery cells, a second subcore including a second plurality of battery cells and electrically connected in series with the first subcore, and a controller including an electronic processor, the method comprising: charging the first plurality of battery cells and the second plurality of battery cells; receiving, using the controller, a first voltage value indicative of a voltage of the first plurality of battery cells from the first subcore; receiving, using the controller, a second voltage value indicative of a voltage of the second plurality of battery cells from the second subcore; determining, using the controller, a difference between the first voltage value and the second voltage value; comparing the difference to a balance threshold; and performing a balancing operation when the difference is greater than or equal to the balance threshold. ### Claim 18 (depends on 17) The method of claim 17, further comprising: comparing, using the controller, the first voltage value to a charge threshold; determining, using the controller, whether the first voltage value is greater than or equal to the charge threshold; and terminating charging of the first plurality of battery cells when the first voltage value is greater than or equal to the charge threshold. ### Claim 19 (depends on 18) The method of claim 18, further comprising: comparing, using the controller, the second voltage value to a charge threshold; determining, using the controller, whether the second voltage value is greater than or equal to the charge threshold; and terminating charging of the second plurality of battery cells when the first voltage value is greater than or equal to the charge threshold. ### Claim 20 (depends on 17) The method of claim 17, wherein performing the balancing operation comprises: determining, using the controller, whether the first voltage value is greater than the second voltage value; charging the second plurality of battery cells for an amount of time when the first voltage value is greater than the second voltage value; delaying charging of the first plurality of battery cells for the amount of time when the first voltage value is greater than the second voltage value; and charging the first plurality of battery cells and the second plurality of battery cells after the amount of time has elapsed.