# US 9,434,272 B2 · Battery management system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,434,272 B2 - Document ID: US9434272B2 - Status: Granted - Kind: B2 - Application number: 14/438,125 - Filed: 2014-09-24 - Published: 2015-10-01 - Granted: 2016-09-06 - Earliest claimed: 2013-09-24 - Assignees: LG Chem, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Ju-Hyun Kang; Dal-Hoon Lee; Sang-Hoon Lee; Dong-Keun Kwon; Yasuhito Eguchi - Web page: https://patentgrep.com/patent/US9434272B2 ## CPC - B60L 58/10: for monitoring or controlling batteries - B60L 58/21: having the same nominal voltage - H02J 7/50: acting upon multiple batteries simultaneously or sequentially - H02J 7/575: {Parallel/serial switching of connection of batteries to charge or load circuit} - H02J 7/82: Control of state of charge [SOC] - H02J 7/855: {with circuits adapted for supplying loads from the battery} - H02J 7/96: in response to battery voltage - B60L 2240/547: Voltage - 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 7/42: with electronic devices having internal batteries, e.g. mobile phones - H02J 2105/16: being internal to power sources or power generation plants - 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 - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract The present disclosure discloses a battery management system that uses a small number of opto-couplers to reduce a production cost. The battery management system is controlled to maintain a turn-off state in a normal condition. Also, switches are connected in series, and the switches are connected such that when any one switch turns on, switches connected subsequent to the turned-on switch turn on in sequential order. The turn-on of the last connected switch causes a switch turning on an opto-coupler to be turned on. As a result, when the opto-coupler turns on, a battery management device may transmit information to an external device. ## Claims ### Claim 1 A battery management system which manages a battery pack including at least two battery assemblies connected in a sequential order, the battery management system comprising: at least two battery management devices each having a first terminal outputting a variable voltage and a second terminal outputting a constant voltage, and provided for each battery assembly; at least two slave switch units connected to each other in sequential order, and provided for each battery management device and connected between the first terminal and the second terminal, the slave switch units selectively turning on or turning off based on the variable voltage outputted from the first terminal; and an information transfer unit to transmit information from the battery management device to an external device, wherein among the slave switch units, when a slave switch unit provided in a battery management device intended to transmit information to the external device turns on, the slave switch units turn on in a sequential order toward a last slave switch unit provided the last among the slave switch units, to form an information transfer path to allow the information transfer unit to transmit the information to the external device. ### Claim 2 (depends on 1) The battery management system according to claim 1, wherein the slave switch unit has a bipolar junction transistor. ### Claim 3 (depends on 2) The battery management system according to claim 2, wherein the bipolar junction transistor is an NPN-type bipolar junction transistor, a base of the NPN-type bipolar junction transistor is connected to the second terminal of the battery management device, an emitter of the NPN-type bipolar junction transistor is connected to the first terminal of the battery management device, and a collector of the NPN-type bipolar junction transistor is connected to a connector node formed on a line connecting an emitter of an NPN-type bipolar junction transistor an adjacent slave switch unit connected in sequential order has and a first terminal of a battery management device provided with the adjacent slave switch unit. ### Claim 4 (depends on 3) The battery management system according to claim 3, further comprising: a master switch unit connected between the information transfer unit and the last slave switch unit, and when the last slave switch unit turns on, the master switch unit turns on. ### Claim 5 (depends on 4) The battery management system according to claim 4, wherein a collector of an NPN-type bipolar junction transistor the last slave switch unit has is connected to the master switch unit, and when the last slave switch unit turns on and an electric current flows to the collector of the NPN-type bipolar junction transistor the last slave switch unit has, the master switch unit turns on. ### Claim 6 (depends on 5) The battery management system according to claim 5, wherein the master switch unit has a bipolar junction transistor. ### Claim 7 (depends on 6) The battery management system according to claim 6, wherein the master switch unit has a PNP-type bipolar junction transistor, and a base of the PNP-type bipolar junction transistor is connected to the collector of the NPN-type bipolar junction transistor the last slave switch unit has. ### Claim 8 (depends on 7) The battery management system according to claim 7, wherein an emitter of the PNP-type bipolar junction transistor the master switch unit has is connected to the second terminal of the battery management device provided with the last slave switch unit. ### Claim 9 (depends on 8) The battery management system according to claim 8, wherein the collector of the PNP-type bipolar junction transistor the master switch unit has is connected to one end of the information transfer unit. ### Claim 10 (depends on 3) The battery management system according to claim 3, wherein a capacitor is provided on a line connecting the base of the NPN-type bipolar junction transistor and the emitter of the NPN-type bipolar junction transistor. ### Claim 11 (depends on 3) The battery management system according to claim 3, wherein a diode is provided on a line connecting the connector node and the first terminal to allow an electric current to flow from the connector node to the first terminal. ### Claim 12 (depends on 3) The battery management system according to claim 3, wherein the last slave switch unit is provided in a battery management device which manages a battery assembly with highest potential among the battery assemblies. ### Claim 13 (depends on 2) The battery management system according to claim 2, wherein the bipolar junction transistor is a PNP-type bipolar junction transistor, a base of the PNP-type bipolar junction transistor is connected to the first terminal of the battery management device, an emitter of the PNP-type bipolar junction transistor is connected to the second terminal of the battery management device, and a collector of the PNP-type bipolar junction transistor is connected to a connector node formed on a line connecting an emitter of a PNP-type bipolar junction transistor an adjacent slave switch unit connected in sequential order has and a second terminal of a battery management device provided with the adjacent slave switch unit. ### Claim 14 (depends on 13) The battery management system according to claim 13, further comprising: a master switch unit connected between the information transfer unit and the last slave switch unit, and when the last slave switch unit turns on, the master switch unit turns on. ### Claim 15 (depends on 14) The battery management system according to claim 14, wherein a collector of a PNP-type bipolar junction transistor the last slave switch unit has is connected to the master switch unit, and when the last slave switch unit turns on and an electric current flows in the collector of the PNP-type bipolar junction transistor the last slave switch unit has, the master switch unit turns on. ### Claim 16 (depends on 15) The battery management system according to claim 15, wherein the master switch unit has a bipolar junction transistor. ### Claim 17 (depends on 16) The battery management system according to claim 16, wherein the master switch unit has an NPN-type bipolar junction transistor, and a base of the NPN-type bipolar junction transistor is connected to the collector of the PNP-type bipolar junction transistor the last slave switch unit has. ### Claim 18 (depends on 17) The battery management system according to claim 17, wherein an emitter of the NPN-type bipolar junction transistor the master switch unit has is connected to the second terminal of the battery management device provided with the last slave switch unit. ### Claim 19 (depends on 18) The battery management system according to claim 18, wherein the collector of the NPN-type bipolar junction transistor the master switch unit has is connected to one end of the information transfer unit. ### Claim 20 (depends on 14) The battery management system according to claim 14, wherein a capacitor is provided on a line connecting the base of the PNP-type bipolar junction transistor and the emitter of the PNP-type bipolar junction transistor. ### Claim 21 (depends on 14) The battery management system according to claim 14, wherein a diode is provided on a line connecting the connector node and the second terminal to allow an electric current to flow from the second terminal to the connector node. ### Claim 22 (depends on 14) The battery management system according to claim 14, wherein the last slave switch unit is provided in a battery management device which manages a battery assembly with lowest potential among the battery assemblies. ### Claim 23 (depends on 1) The battery management system according to claim 1, wherein the slave switch unit turns on when the variable voltage outputted form the first terminal is lower than the constant voltage outputted from the second terminal. ### Claim 24 (depends on 1) The battery management system according to claim 1, wherein the information transfer unit is an opto-coupler which disconnects the information transfer unit from the external device while transmitting the information to the external device. ### Claim 25 (depends on 1) A battery pack comprising: a battery management system according to claim 1. ### Claim 26 (depends on 25) A battery operating system comprising: a battery pack according to claim 25; and a load which is supplied with power from the battery pack.