Battery Systems

Abstract

The battery system includes a battery pack including a plurality of battery cells, a BMIC that monitors a plurality of cell voltages for each of the plurality of battery cells, a plurality of balancing batteries that are charged by target battery cells among the plurality of battery cells that require cell balancing, a power conversion unit that includes a DC-DC converter that receives voltage input from the plurality of balancing batteries and converts it into an output voltage, and a power supply unit that supplies the output voltage to the BMIC when the output voltage is equal to or higher than a predetermined level for driving the BMIC.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2021-0157764 dated November 16, 2021, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery system. [Background technology]

[0003] The battery pack may include a plurality of battery cells connected in series and / or parallel. When the battery pack includes a plurality of battery cells, a cell balancing operation is performed to balance the voltages of the plurality of battery cells. The cell balancing operation may be realized by discharging a current flowing through a battery cell in which deviation has occurred among the plurality of battery cells through a balancing load.

[0004] In addition, a battery monitoring integrated circuit that monitors the voltage of a battery cell requires a power supply for performing a voltage monitoring operation, and also requires a standby power supply even during periods when monitoring is not performed, so a power supply is required to supply power to the battery monitoring integrated circuit. Summary of the Invention [Problem to be solved by the invention]

[0005] A battery system is provided that can supply power to a battery monitoring integrated circuit using power consumed during cell balancing operation between a plurality of battery cells in a battery pack including a plurality of battery cells. [Means for solving the problem]

[0006] A battery system according to one embodiment of the present invention includes a battery pack including a plurality of battery cells, a BMIC that monitors a plurality of cell voltages for each of the plurality of battery cells, a plurality of balancing batteries that are charged by target battery cells among the plurality of battery cells that require cell balancing, a power conversion unit including a DC-DC converter that receives voltage input from the plurality of balancing batteries and converts it into an output voltage, and a power supply unit that supplies the output voltage to the BMIC when the output voltage is equal to or greater than a predetermined level for powering the BMIC.

[0007] If the output voltage is less than a predetermined level for driving the BMIC, the power supply unit can adjust the voltage supplied from the battery pack to the predetermined level for driving the BMIC and supply it to the BMIC.

[0008] The battery cell balancing device may further include a plurality of MUXes that connect a target battery cell that requires cell balancing among the plurality of battery cells to one of the plurality of balancing batteries.

[0009] The power conversion unit may operate the DC-DC converter when a voltage output from the plurality of balancing batteries is equal to or greater than a predetermined critical voltage.

[0010] The power conversion unit further includes an ADC that measures voltages output from the multiple balancing batteries and generates a voltage measurement signal, and whether or not the multiple balancing batteries are charged by the target battery cell can be controlled based on the voltage measurement signal.

[0011] The power conversion unit does not need to operate while the ADC measures the voltages output from the multiple balancing batteries.

[0012] The battery may further include a PTC element located on a current path along which one of the balancing batteries is charged by cell balancing of the target battery cell.

[0013] When multiple balancing batteries are connected in parallel with each other, the balancing battery may further include a PTC element located on a current path between the multiple balancing batteries.

[0014] The power supply unit may include a resistor connected to a wire connected to the battery pack, a capacitor charged with a voltage generated using the voltage of the battery pack, and a transistor having a base terminal to which a driving voltage supplied from the BMIC is input, a resistor connected to a collector terminal, and a capacitor connected to an emitter terminal, and operating when the voltage of the emitter terminal does not reach the voltage level of the base terminal to supply the voltage generated from the voltage of the collector terminal to the BMIC.

[0015] In addition, a battery system according to another aspect of the invention includes a battery pack including a plurality of battery cells, a BMIC that measures a plurality of cell voltages for each of the plurality of battery cells, an MCU that receives the plurality of cell voltages and determines a target battery cell that requires cell balancing among the plurality of battery cells, a plurality of balancing batteries that are charged by cell balancing, a MUX that connects the determined target battery cell to a corresponding one of the plurality of balancing batteries according to control of the MCU, a DC-DC converter that converts voltage input from the plurality of balancing batteries to generate an output voltage, and a power supply unit that supplies the higher of voltages generated using the output voltage of the DC-DC converter and the voltage of the battery pack to the BMIC.

[0016] The DC-DC converter can operate when the voltage input from the multiple balancing batteries is equal to or greater than a predetermined critical voltage.

[0017] According to yet another feature of the present invention, the battery system includes a plurality of battery packs each including a plurality of battery cells, and a plurality of slave BMSs for managing the battery pack for each of the plurality of battery packs, each of the plurality of slave BMSs including a BMIC connected to a corresponding plurality of battery cells and measuring a plurality of cell voltages to control cell balancing, a plurality of balancing batteries included in each of the plurality of slave BMSs and charged by cell balancing, a DC-DC converter for converting voltage supplied from the plurality of balancing batteries to generate an output voltage, and a power supply unit for supplying the higher of voltages generated using the output voltage of the DC-DC converter and the voltage of the battery packs to the BMIC.

[0018] The master BMS may further include a master BMS that receives voltage measurement signals measuring voltages supplied from the multiple balancing batteries from the multiple slave BMSs, generates control signals capable of controlling the multiple slave BMSs based on the voltage measurement signals, and transmits the control signals to the multiple slave BMSs.

[0019] When the voltage supplied from the multiple balancing batteries is equal to or greater than a predetermined critical voltage, the master BMS may generate a control signal including a control command to turn on the DC-DC converter. Effect of the Invention

[0020] A battery system is provided that can supply power to a battery monitoring integrated circuit using power consumed during a cell balancing operation between a plurality of battery cells in a battery pack including a plurality of battery cells, thereby reducing power consumption of the battery system. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a circuit diagram that diagrammatically illustrates a battery system according to one embodiment. [Diagram 2] FIG. 2 illustrates a MUX according to one embodiment. [Diagram 3]FIG. 2 illustrates a balancing battery section according to one embodiment. [Figure 4] 1 is a diagram illustrating a state in which a PTC unit, a power conversion unit, and a power supply unit are connected to each other. [Diagram 5] FIG. 1 is a circuit diagram that diagrammatically illustrates a battery system with a current sensor according to one embodiment. [Figure 6] 1 is a schematic diagram illustrating a connection relationship of a battery system connected to a plurality of battery packs according to an embodiment; [Figure 7] FIG. 7 is a circuit diagram illustrating an embodiment of a detailed configuration of the SBMS of FIG. 6. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings. The same or similar components are given the same or similar drawing reference numerals, and the duplicated description thereof will be omitted. The suffixes "module" and / or "part" for components used in the following description are given or mixed for the sake of ease of specification writing only, and do not have any meaning or role of distinguishing each other. In addition, when describing the embodiments disclosed in this specification, if a specific description of related publicly known technology is deemed to obscure the gist of the embodiments disclosed in this specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are provided to facilitate understanding of the embodiments disclosed in this specification, and the technical ideas disclosed in this specification are not limited by the accompanying drawings, and should be understood as including all modifications, equivalents, or alternatives included in the ideas and technical scope of the present invention.

[0023] Terms including ordinal numbers such as first, second, etc. may be used to describe various components, but the components are not limited by these terms. The above terms are used only to distinguish one component from another component.

[0024] As used herein, terms such as "comprise" or "have" are intended to specify the presence of a specified feature, number, step, operation, component, part, or combination thereof, and should be understood as not precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0025] In one embodiment, a configuration that controls another configuration under a specific control condition may incorporate a program implemented as a set of instructions that embodies a control algorithm required to control the other configuration. The control configuration may process input data and stored data based on the installed program to generate output data. The control configuration may include a non-volatile memory that stores the program and a memory that stores the data.

[0026] FIG. 1 is a circuit diagram illustrating a battery system according to one embodiment.

[0027] 1, the battery system 1 may include a battery pack 10, a battery monitoring integrated circuit 20, a main control unit 30, a plurality of MUXes 40 and 41, a balancing battery unit 50, a PTC unit 60, a power conversion unit 70, a power supply unit 80, and relays 90 and 91. Hereinafter, the battery monitoring integrated circuit is referred to as a BMIC (Battery Monitoring Integrated Circuit). Hereinafter, the main control unit is referred to as an MCU (Main Control Unit).

[0028] The external device 2 may include a load such as an inverter or a converter and a charging device. When the external device 2 is a charger, both ends of the battery system 1 are connected to the charger and the battery system 1 is charged by receiving power from the charger. When the external device 2 is a load, both ends of the battery system 1 are connected to the load and the power supplied by the battery pack 10 is discharged through the load.

[0029] The battery pack 10 includes a plurality of battery cells 11-16 connected in series. Although the battery pack 10 includes six battery cells 11-16 connected in series in FIG. 1, this is an example, and the present invention is not limited thereto. The battery pack 10 may be realized as two or more battery cells connected in series, or two or more battery cells connected in parallel may be realized as a plurality of battery cells connected in series.

[0030] Hereinafter, cell balancing as described herein refers to a charge equalization operation for battery cells having a value equal to or greater than a reference value among the plurality of battery cells 11-16 included in the battery pack 10. The reference value is a value set based on the cell voltages of the plurality of battery cells 11-16, and may be a representative value for the plurality of cell voltages. The representative value may be an average value, a median value, a minimum value, or the like. A conventional charge equalization operation may be implemented by transferring charges stored in a cell requiring cell balancing to a battery cell having a lower cell voltage, or by discharging charges stored in a cell requiring cell balancing using a discharge load. However, according to an embodiment, the charge equalization operation may be implemented by transferring charges stored in a cell requiring cell balancing to a balancing battery.

[0031] The power consumed by the BMIC20 is classified into monitoring power required for monitoring and standby power in a sleep state. Monitoring power is power consumed when the BMIC20 performs monitoring. Standby power is power consumed when the BMIC20 is in a sleep state and not performing monitoring. Since standby power is also consumed during long-term transportation and storage, both the monitoring power and standby power must be taken into consideration when calculating the power consumption of the BMIC20. The charging energy of each of the multiple battery cells 11-16 may decrease due to the power consumption of the BMIC20.

[0032] Hereinafter, with reference to FIG. 1 to FIG. 5, an embodiment in which a balancing battery is charged with energy generated in an equal charging operation of cells that require cell balancing, and the power charged in the balancing battery is supplied to the BMIC 20 will be described.

[0033] The BMIC 20 is connected to each of the battery cells 11-16, and obtains a plurality of voltage measurement signals VS1-VS7 measured across the battery cells 11-16 via a plurality of input terminals P1-P7. The positive electrode of each of the battery cells 11-16 (e.g., 11) is connected to a corresponding input terminal (e.g., P1) among the input terminals P1-P6 via wiring, and the negative electrode of each of the battery cells 11-16 (e.g., 11) is connected to a corresponding input terminal (e.g., P2) among the input terminals P2-P7 via wiring. For example, the measurement signal VS1 is the positive electrode voltage of the battery cell 11 and is input to the BMIC 20 via the input terminal P1, and the measurement signal VS2 is the negative electrode voltage of the battery cell 11 or the positive electrode voltage of the battery cell 12 and is input to the BMIC 20 via the input terminal P2.

[0034] The BMIC 20 transmits a plurality of cell voltage signals indicating cell voltages of the plurality of battery cells derived from the plurality of voltage measurement signals VS1-VS7 to the MCU 30. For example, the BMIC 20 may generate cell voltage signals according to a voltage obtained by subtracting the negative pole voltage from the positive pole voltage of each of the plurality of battery cells, and transmit the cell voltage signals to the MCU 30.

[0035] The MCU 30 receives a plurality of cell voltage signals, and determines a battery cell (hereinafter, referred to as a "target battery cell") that requires cell balancing among the plurality of battery cells 11-16 based on the plurality of cell voltage signals. The MCU 30 controls the target battery cell to be connected to the balancing battery unit 50 via the plurality of MUXes 40 and 41, and then controls the balancing battery unit 50 to be connected to the power conversion unit 70 via the PTC unit 60, and controls the power conversion unit 70 to supply power to the BMIC 20. When the target battery cell is connected to the corresponding balancing battery of the balancing battery unit 50 via the corresponding MUX among the plurality of MUXes 40 and 41, the corresponding balancing battery is charged by the energy discharged from the target battery cell. When the balancing battery unit 50 and the power conversion unit 70 are connected, the power conversion unit 70 can convert the voltage stored in the balancing battery unit 50 to a voltage level suitable for driving the BMIC 20 and supply it to the BMIC 20.

[0036] For the above control, the MCU 30 generates a plurality of MUX control signals MCS1, MCS2 and transmits them to the plurality of MUXes 40, 41, generates a plurality of switch control signals SC1-SC4 and transmits them to the PTC unit 60, and transmits them to the power conversion unit 70 via a converter control signal CCS. The MCU 30 controls whether to enable the power conversion unit 70 via the converter control signal CCS, and receives a battery signal BS generated from the battery ADC of the power conversion unit 70.

[0037] Each of the multiple MUXes 40 and 41 connects a target battery cell among the corresponding multiple battery cells to the balancing battery unit 50. The multiple battery cells corresponding to each of the multiple MUXes 40 and 41 refer to the multiple battery cells connected to the corresponding MUX. In FIG. 1, the MUX 40 is connected to three battery cells 11-13, and the MUX 41 is connected to three battery cells 14-16.

[0038] Each of the multiple MUXes 40, 41 (e.g., 40) may connect the positive electrode and the negative electrode of a target battery cell among the multiple battery cells (e.g., 11-13) connected among the multiple battery cells 11-16 to corresponding wirings 101, 102 among the multiple wirings 101-104. Although FIG. 1 shows a case where the number of the multiple MUXes 40, 41 is two, the invention is not limited thereto, and the battery system 1 may include one or more MUXes. The following description of the operation of MUX 40 may also be applied to MUX 41.

[0039] The MUX 40 connects a target battery cell among the corresponding battery cells 11-13 to the balancing battery unit 50 in response to a plurality of MUX control signals MCS1. The MUX 41 connects a target battery cell among the corresponding battery cells 14-16 to the balancing battery unit 50 in response to a plurality of MUX control signals MCS2. The plurality of control signals MCS1 may include a plurality of switching signals MS1-MS6 for controlling a plurality of switching elements constituting the MUX circuit 40.

[0040] One end of the relays 90, 91 is connected to the battery pack 10, and the other end of the relays 90, 91 is connected to at least one component of the external device 2. The closing and opening of the relays 90, 91 is controlled in response to relay control signals RSC1, RSC2 supplied from the MCU 30.

[0041] FIG. 2 is a diagram illustrating a MUX according to one embodiment.

[0042] When a target battery cell is determined from among the plurality of battery cells 11-16, the MCU 30 generates a plurality of MUX control signals MCS1 and MCS2 for connecting the target battery cell to the battery balancing unit 50.

[0043] As shown in FIG. 2, the MUX 40 includes a plurality of switching elements 411-416, and each of the plurality of switching signals MS1-MS6 controls the switching operation of the corresponding switching element. When the battery cell 11 of the plurality of battery cells 11-13 is a target battery cell, the MCU 30 generates the switching signals MS1 and MS4 of the on level among the plurality of switching signals MS1-MS6, and the switching elements 411 and 414 are turned on by the switching signals MS1 and MS4 of the on level. Then, the battery cell 11 may be connected to the balancing battery unit 50 through the MUX 40. At this time, the switching signals MS2, MS3, MS5, and MS6 of the off level are supplied from the MCU 30 to the plurality of switching elements 412, 413, 415, and 416 connected to the battery cells 12 and 13 that are not the target battery cells, and the plurality of switching elements 412, 413, 415, and 416 may be in an off state.

[0044] MUX41 also contains the same components as MUX40 and can operate in the same manner.

[0045] According to one embodiment, selecting a target battery cell from among a plurality of battery cells (e.g., 11-13) and connecting the positive and negative electrodes of the target battery cell to wiring 101 and wiring 102, respectively, may be implemented by a circuit including a field effect transistor (FET) element instead of MUX40.

[0046] In the balancing battery section 50, the balancing battery is charged by receiving energy from the target battery cell connected via the wiring 101 and the wiring 102.

[0047] FIG. 3 is a diagram illustrating a balancing battery section according to one embodiment.

[0048] The detailed configuration of the balancing battery unit 50 will be described below with reference to FIG.

[0049] The balancing battery section 50 may include a plurality of balancing batteries 500, 501 and a plurality of PTC elements 510, 511.

[0050] FIG. 1 shows a case where the number of the balancing batteries 500, 501 and the number of the PTC elements 510, 511 are two, respectively, but the present invention is not limited to this, and the number of each may increase or decrease based on the number of MUXes.

[0051] The positive electrode of the balancing battery 500 is connected to the wiring 101, and the negative electrode of the balancing battery 500 is connected to the wiring 102. The PTC element 510 is formed on the wiring 101. The PTC element 510 may be formed on the wiring 102, unlike the illustration of FIG. 3. The PTC element 510 may be realized as a resistive element having a positive temperature coefficient. When the balancing battery 500 is connected to a target battery cell among the plurality of battery cells 11-13 and charged, if the temperature increases due to the charging current, the resistance of the PTC element 510 increases to limit the charging current. For example, the resistance of the PTC element 510 increases rapidly due to heat generated during a short circuit, and the current flowing through the wiring 101 can be blocked.

[0052] The positive electrode of the balancing battery 501 is connected to the wiring 103, and the negative electrode of the balancing battery 501 is connected to the wiring 104. The PTC element 511 is formed on the wiring 103. The PTC element 511 may be formed on the wiring 104, unlike the illustration of FIG. 3. The PTC element 511 may be embodied as a resistive element having a positive temperature coefficient. When the balancing battery 501 is connected to a target battery cell among the plurality of battery cells 14-16 and charged, if the temperature increases due to the charging current, the resistance of the PTC element 511 increases to limit the charging current. For example, the resistance of the PTC element 511 increases rapidly due to heat generated during a short circuit, and the current flowing through the wiring 103 may be blocked.

[0053] Hereinafter, the detailed configurations of the PTC unit 60, the power conversion unit 70, and the power supply unit 80 will be described with reference to FIG.

[0054] FIG. 4 is a schematic diagram showing a state in which the PTC unit, the power conversion unit, and the power supply unit are connected to each other.

[0055] The PTC section 60 includes four switches 601 - 604 and a PTC element 600 .

[0056] The switch 601 is connected between the wire 105 and the wire 110, and controls the connection between the balancing battery 500 and the input terminal P71 of the DC-DC converter 700 by switching operation according to a switch control signal SC1. The switch 602 is connected between the wire 106 and the wire 109, and controls the connection between the balancing battery 500 and the input terminal P72 of the DC-DC converter 700 by switching operation according to a switch control signal SC2. The switch 603 is connected between the wire 107 and the wire 110, and controls the connection between the balancing battery 501 and the input terminal P71 of the DC-DC converter 700 by switching operation according to a switch control signal SC3. The switch 604 is connected between the wire 108 and the wire 109, and controls the connection between the balancing battery 500 and the input terminal P72 of the DC-DC converter 700 by switching operation according to a switch control signal SC4.

[0057] The on-levels of the switch control signals SC1-SC4 may be high levels and the off-levels may be low levels, i.e., the switches 601-604 are turned on in response to the switch control signals SC1-SC4 at a high level, and the switches 601-604 are turned off in response to the switch control signals SC1-SC4 at a low level.

[0058] While the balancing battery 500 is being charged by the target battery cell via the wires 101 and 102, the switches 601 and 602 are turned off by the low-level switch control signals SC1 and SC2. While the balancing battery 501 is being charged by the target battery cell via the wires 103 and 104, the switches 603 and 604 are turned off by the low-level switch control signals SC3 and SC4.

[0059] After the balancing operation is completed, the switches 601-604 are turned on by the switch control signals SC1-SC4 at a high level.

[0060] When the multiple switches 601-604 are on, the positive electrode of the balancing battery 500 is connected to the input terminal P71 of the DC-DC converter 700 via wirings 105 and 110, the negative electrode of the balancing battery 500 is connected to the input terminal P72 of the DC-DC converter 700 via wirings 106 and 109, the positive electrode of the balancing battery 501 is connected to the input terminal P71 of the DC-DC converter 700 via wirings 107 and 110, and the negative electrode of the balancing battery 501 is connected to the input terminal P72 of the DC-DC converter 700 via wirings 108 and 109.

[0061] When the switches 601-604 are turned on, a potential difference between the balancing batteries 500, 501 may cause balancing between the balancing batteries 500, 501. The PTC unit 60 may include a PTC element 600 to limit such balancing between the balancing batteries 500, 501.

[0062] The PTC element 600 is formed on the current path between the balancing batteries 500, 501. In FIG. 4, the PTC element 600 is formed on the wiring 105. The PTC element 600 may be formed on the wiring 107, different from the illustration in FIG. 4. When the multiple switches 601-604 are all in the on state, a balancing current flows due to balancing between the balancing battery 500 and the balancing battery 501. Since the PTC element 600 is located on the path of the balancing current, the resistance increases as the balancing current increases, thereby limiting the balancing current. When a short circuit occurs due to the balancing current, the resistance of the PTC element 600 increases rapidly, thereby cutting off the balancing current.

[0063] The power conversion unit 70 includes a DC-DC converter 700 and an analog-digital converter (ADC) 710.

[0064] The ADC 710 receives the voltages of the balancing batteries 500, 501 and transmits the generated battery voltage measurement signal BS to the MCU 30 via the wiring 110. The MCU 30 checks the voltages of the balancing batteries 500, 501 after balancing based on the voltage measurement signal BS received from the ADC 710 and controls the multiple MUXes 40, 41 so that the balancing batteries 500, 501 do not enter an overvoltage state. For example, when at least one of the balancing batteries 500, 501 is in an overvoltage state, the MCU 30 can maintain the multiple MUX control signals MCS1, MCS2 at an off level and discharge the target battery cell via another cell balancing circuit, for example, a passive cell balancing circuit, even if there is a battery cell that needs balancing among the multiple battery cells 11-16.

[0065] While measuring the voltages of the balancing batteries 500 and 501, the MCU 30 supplies an off-level voltage to the hold terminal 720 via the converter control signal CCS to stop the operation of the DC-DC converter 700.

[0066] The hold terminal 720 is connected to the junction between the two resistors R1 and R2, and the voltage of the hold terminal 720 is supplied to the enable pin P70 to control the operation of the DC-DC converter 700. For example, when the voltage of the hold terminal 720 falls below a predetermined critical voltage, the DC-DC converter 700 does not operate. The voltage of the hold terminal 720 may be a voltage obtained by dividing the voltage of the input terminal P71 of the DC-DC converter 700 by the two resistors R1 and R2 and distributing it to the enable pin P70. When the voltage of the hold terminal 720 falls below the predetermined critical voltage, it indicates that the voltage of the input terminal P71 has fallen below a predetermined critical value.

[0067] Alternatively, the MCU 30 supplies an on-level converter control signal CCS to the hold terminal 720 to operate the DC-DC converter 700. Also, the MCU 30 can supply an off-level converter control signal CCS to the hold terminal 720 to stop the operation of the DC-DC converter 700. In this case, the voltage of the hold terminal 720 does not depend on the voltage supplied from the balancing battery unit 50.

[0068] The power conversion unit 70 maintains the output voltage of the DC-DC converter 700 at a predetermined level via the hold terminal 720. Here, the predetermined level may be a normal level that can drive the BMIC 20.

[0069] The power supply unit 80 operates based on a drive voltage supplied from terminal P8 of the BMIC 20 via wiring 112, and adjusts the voltage supplied from the battery pack 10 via wiring 113 to a power supply voltage at a level suitable for the BMIC 20 and supplies it to terminal P9 of the BMIC 20.

[0070] The output voltage supplied from the power conversion unit 70 is transmitted to the power supply unit 80 through the wiring 111, and the power supply unit 80 does not operate when the output voltage of the power conversion unit 70 is at a normal level. For example, the normal level may be a level suitable for driving the BMIC 20.

[0071] The power supply unit 80 includes a transistor Q1, a resistor R, and a capacitor C. One end of the resistor R is connected to a wiring 113 connected to the positive electrode of the battery pack 10, the other end of the resistor R is connected to a collector end of a transistor Q1, the emitter end of the transistor Q1 is connected to one end of a capacitor C, and the other end of the capacitor C is connected to the ground. A driving voltage supplied from the BMIC 20 is input to the base end of the transistor Q1. The BMIC 20 is supplied with the voltage charged in the capacitor C of the power supply unit 80 as a power supply voltage, and can adjust the power supply voltage by controlling the switching operation of the transistor Q1 according to the level of the power supply voltage.

[0072] The output terminal of the DC-DC converter 700 is connected to a junction between the emitter terminal of the transistor Q1 and one terminal of the capacitor C through a wiring 111. At this time, when the output voltage of the DC-DC converter 700 is at a normal level, the output voltage of the DC-DC converter 700 may be equal to or higher than the driving voltage. That is, when the output voltage of the DC-DC converter 700 is at a normal level, the transistor Q1 of the power supply unit 80 does not operate, so that the power supply voltage is not supplied from the power supply unit 80 to the BMIC 20, and the output voltage of the DC-DC converter 700 becomes the power supply voltage of the BMIC 20. When the output voltage of the DC-DC converter 700 is at a normal level, the output voltage of the DC-DC converter 700 is directly supplied to the BMIC 20 through the wiring 111. Also, when the output voltage of the DC-DC converter 700 drops to a level lower than the normal level, the transistor Q1 of the power supply unit 80 operates. Then, the power supply voltage is supplied from the power supply unit 80 to the BMIC 20 instead of the output voltage of the DC-DC converter 700. Therefore, the power supply unit 80 can supply the higher of the voltages generated using the output terminal voltage of the DC-DC converter 700 and the voltage of the battery pack 10 to the BMIC 20 as a power supply voltage.

[0073] FIG. 5 is a circuit diagram that illustrates a battery system with a current sensor according to one embodiment.

[0074] Referring to FIG. 5, the battery system 1000 includes current sensors 51 and 52 between the multiple MUXes 40 and 41 and the balancing battery section 50.

[0075] A battery system 1000 in FIG. 5 is similar to the battery system 1 in FIG. 1 except that a current sensor 51 is added, and therefore a duplicated description will be omitted.

[0076] The current sensor 51 checks the amount of current flowing through the wiring that connects the target battery cell and the balancing batteries 500, 501. In FIG. 5, the current sensor 51 is provided on the wiring 101, and the current sensor 52 is provided on the wiring 103, but the invention is not limited thereto. The current sensors 51, 52 may be provided on at least one of the wirings 101-104 that connect the target battery cell and the balancing battery. The current sensors 51, 52 may be implemented as Hall sensors. The current sensors 51, 52 measure the current flowing through the wirings 101, 103, generate a current measurement signal (not shown), and transmit it to the MCU 30. The MCU 30 detects the charging current of the balancing batteries 500, 501 based on the received current measurement signal, and estimates the charge amount of the balancing batteries 500, 501 or detects an overcurrent to control a protection operation.

[0077] Hereinafter, a case where a battery system includes a plurality of battery packs will be described with reference to FIGS.

[0078] FIG. 6 is a diagram illustrating a connection relationship of a battery system connected to a plurality of battery packs according to an embodiment.

[0079] The battery system 2000 may include a plurality of battery packs 100, 200, 300, a master battery management system (MBMS, 21), and a plurality of slave battery management systems (SBMS, 22-24). Although the plurality of battery packs 100, 200, 300 each includes six battery cells connected in series, this is an example, and the invention is not limited thereto, and each of the plurality of battery packs 100, 200, 300 may be embodied as a plurality of battery cells connected in series, or a plurality of battery cells connected in parallel. In FIG. 6, the battery system 2000 includes three battery packs 100, 200, 300 connected in series, but this is an example, and the invention is not limited thereto, and the battery system 2000 may include two or more battery packs.

[0080] 6, when a battery system includes a plurality of battery packs 100, 200, 300, each of the plurality of battery packs 100, 200, 300 (e.g., 100) is connected to a corresponding SBMS 22 among a plurality of SBMSs 22-24. Each of the plurality of SBMSs 22-24 (e.g., 22) is connected to a respective one of a plurality of battery cells of the corresponding battery pack (e.g., 100).

[0081] The MBMS 21 can perform the functions performed by the MCU 30 of the embodiment shown in Figures 1 and 5. The multiple SBMSs 22-24 measure information (e.g., multiple cell voltages, battery pack temperature, etc.) required to manage the battery system 2000, and send signals indicating the measurement results to the MBMS 21 via wired or wireless communication. Figure 6 shows a case in which the MBMS 21 and the multiple SBMSs 22-24 are connected to each other in a daisy chain structure, but this is just an example and the invention is not limited to this, and the MBMS 21 and the multiple SBMSs 22-24 can be directly or indirectly connected to each other and communicate with each other via wired or wireless communication.

[0082] Fig. 7 is a circuit diagram showing a detailed configuration of the SBMS shown in Fig. 6. The BMS 22 shown in Fig. 7 is related to one of the SBMS 22-24 shown in Fig. 6, but can be similarly applied to each of the multiple SBMSs 22-24.

[0083] In the battery system 1,1000 shown in Figures 1 and 5, the operation of the MCU 30 controlling multiple MUXs 40, 41, the PTC unit 60 and the power conversion unit 70 can be implemented in the battery system 2000 of Figure 7 by the MBMS 31 controlling multiple MUXs 40, 41, the PTC unit 60 and the power conversion unit 70.

[0084] The BMIC 220 generates a slave signal SS including a plurality of cell voltages of the plurality of battery cells 1001-1006, the temperature of the battery pack 100, a battery signal BS received from the battery ADC of the power conversion unit 70, and the like, and transmits the signal to the MBMS 21.

[0085] The MBMS 21 generates a control signal CS capable of controlling the multiple SBMSs 22-24 based on the slave signals SS received from the multiple SBMSs 22-24. The MBMS 21 transmits the generated control signal CS to the multiple SBMSs 22-24. The control signal CS can include multiple MUX control signals MCS1-MCS2, multiple switch control signals SC1-SC4, and converter control signals CCS.

[0086] The MBMS 21 determines a target battery cell that requires cell balancing among the plurality of battery cells 1001-1006, controls the plurality of MUXes 40, 41 to connect the target battery cell to the balancing battery unit 50 via the plurality of MUXes 40, 41, and then controls the target battery cell to be connected to the power conversion unit 70 via the PTC unit 60, and controls the power conversion unit 70 to supply power to the BMIC 220. The MBMS 21 generates a signal CS including a control command for the above-mentioned control and transmits it to the SBMS 22. The MBMS 21 may generate a control command corresponding to each SBMS not only for the SBMS 22 but also for the SBMSs 23, 24 in the same manner, and generate a signal CS including a control command corresponding to the plurality of SBMSs 22-24 and transmit it to the plurality of SBMSs 22-24.

[0087] The BMIC 220 generates a plurality of MUX control signals MCS1, MCS2 in response to a signal CS received from the MBMS 21 and transmits them to the plurality of MUXes 40, 41, generates a plurality of switch control signals SC1-SC4 and transmits them to the PTC unit 60, and transmits them to the power conversion unit 70 via a converter control signal CCS. The BMIC 220 can control whether to enable the power conversion unit 70 via the converter control signal CCS.

[0088] When a target battery cell is connected to a corresponding balancing battery of the balancing battery unit 50 via a corresponding MUX among the multiple MUXes 40 and 41, the corresponding balancing battery is charged by the energy discharged from the target battery cell. When the balancing battery unit 50 and the power conversion unit 70 are connected, the power conversion unit 70 can convert the voltage stored in the balancing battery unit 50 to a voltage level suitable for driving the BMIC 220 and supply it to the BMIC 220.

[0089] For example, when the input voltage input to the power conversion unit 70 of the SBMS 22 in response to the slave signal SS is equal to or higher than a predetermined voltage, the MBMS 21 transmits to the BMIC 220 a control signal CS including a control command for enabling the power conversion unit 70 so that the BMIC 220 receives power from the power conversion unit 70. The BMIC 220 generates a converter control signal CCS for enabling the power conversion unit 70 in response to the control signal CS and transmits it to the power conversion unit 70.

[0090] Furthermore, if at least one of the balancing batteries included in the balancing battery unit 50 of the SBMS 22 is in an overvoltage state in response to the slave signal SS, the MBMS 21 may transmit to the BMIC 220 a control signal CS including a control command for the BMIC 220 not to operate the MUXes 40, 41. In response to the control signal CS, the BMIC 220 may generate and transmit to the MUXes 40, 41 a plurality of MUX control signals MCS1, MCS2 of an off level for maintaining the MUXes 40, 41 in an off state even if there is a battery cell that requires balancing among the battery cells 1001-1006.

[0091] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those having ordinary skill in the field to which the present invention pertains also fall within the scope of the present invention. [Explanation of symbols]

[0092] 1 Battery System 2 External device 10 Battery pack 11-16 Battery Cell 20 Battery Monitoring Integrated Circuit 30 Main control section 40 MUX circuits 50 Balancing battery section 51,52 Current sensor 60 PTC Department 70 Power conversion section 80 Power supply section 90,91 Relay 100 Battery Pack 101-113 Wiring 200 Battery Pack 300 Battery Pack 411-416 Switching elements 500 Balancing Battery 501 Balancing Battery 510,511 PTC element 600 PTC elements 601-604 Switch 700 DC-DC Converter 710 Analog-to-Digital Converter (ADC) 720 Hold terminal 1000 Battery System 1001-1006 Battery Cells 2000 Battery System

Claims

1. a battery pack including a plurality of battery cells; a BMIC configured to monitor a plurality of cell voltages for each of the plurality of battery cells; a plurality of balancing batteries to be charged by target battery cells that require cell balancing among the plurality of battery cells; a power conversion unit including a DC-DC converter that receives a voltage input from the plurality of balancing batteries and converts it into an output voltage; a power supply unit that supplies the output voltage to the BMIC when the output voltage is equal to or higher than a predetermined level for driving the BMIC; wherein power consumption by driving the BMIC includes monitoring power and standby power.

2. The power supply unit includes:

2. The battery system according to claim 1, wherein if the output voltage is less than a predetermined level for driving the BMIC, the voltage supplied from the battery pack is adjusted to a predetermined level for driving the BMIC and supplied to the BMIC.

3. a plurality of MUXs that connect a target battery cell that requires cell balancing among the plurality of battery cells to one of the plurality of balancing batteries; The battery system of claim 1 further comprising:

4. The power conversion unit is 2. The battery system according to claim 1, wherein the DC-DC converter is operated when a voltage output from the plurality of balancing batteries is equal to or higher than a predetermined critical voltage.

5. The power conversion unit is The balancing battery further includes an ADC that measures voltages output from the plurality of balancing batteries to generate a voltage measurement signal; The battery system according to claim 1 , wherein whether or not the target battery cell charges the plurality of balancing batteries is controlled based on the voltage measurement signal.

6. The battery system according to claim 5 , wherein the power conversion unit does not operate while the ADC measures voltages output from the plurality of balancing batteries.

7. a PTC element located on a current path along which one of the plurality of balancing batteries is charged by cell balancing of the target battery cell; The battery system of claim 1 further comprising:

8. When the balancing batteries are connected in parallel, a PTC element is disposed on a current path between the balancing batteries. The battery system of claim 1 further comprising:

9. The power supply unit includes: a resistor connected to a wire connected to the battery pack; a capacitor to which a voltage generated using the voltage of the battery pack is charged; a transistor having a base terminal to which a driving voltage supplied from the BMIC is input, a collector terminal to which the resistor is connected, and an emitter terminal to which the capacitor is connected, and which operates when the voltage of the emitter terminal does not reach the voltage level of the base terminal to supply a voltage generated from the voltage of the collector terminal to the BMIC; The battery system of claim 1 .

10. a battery pack including a plurality of battery cells; a BMIC for measuring a plurality of cell voltages for each of the plurality of battery cells; an MCU that receives the plurality of cell voltages and determines a target battery cell that requires cell balancing among the plurality of battery cells; a plurality of balancing batteries that are charged by cell balancing; a MUX that is connected to the determined target battery cell and a corresponding one of the plurality of balancing batteries according to control of the MCU; a DC-DC converter that converts a voltage input from the plurality of balancing batteries to generate an output voltage; a power supply unit that supplies the higher voltage of a voltage generated using an output voltage of the DC-DC converter and a voltage of the battery pack to the BMIC; wherein power consumption by driving the BMIC includes monitoring power and standby power.

11. The DC-DC converter comprises: The battery system according to claim 10, which operates when a voltage input from the plurality of balancing batteries is equal to or greater than a predetermined critical voltage.

12. A plurality of battery packs each including a plurality of battery cells, a plurality of battery packs, each of which includes a BMIC connected to a corresponding battery cell, for measuring a plurality of cell voltages and controlling cell balancing; A plurality of balancing batteries included in each of the plurality of slave BMSs and charged by cell balancing; a DC-DC converter that converts voltages supplied from the plurality of balancing batteries to generate an output voltage; a power supply unit that supplies the higher voltage of a voltage generated using an output voltage of the DC-DC converter and a voltage of the battery pack to the BMIC; wherein power consumption by driving the BMIC includes monitoring power and standby power.

13. a master BMS that receives voltage measurement signals measuring voltages supplied from the plurality of balancing batteries from the plurality of slave BMSs, generates control signals for controlling the plurality of slave BMSs based on the voltage measurement signals, and transmits the control signals to the plurality of slave BMSs. The battery system of claim 12 further comprising:

14. The battery system of claim 13, wherein the master BMS generates a control signal including a control command to turn on the DC-DC converter when a voltage supplied from the plurality of balancing batteries is equal to or higher than a predetermined critical voltage.

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