Battery system

Abstract

The battery system includes a battery pack comprising 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 a target battery cell requiring cell balancing among the plurality of battery cells, a power conversion unit comprising a DC-DC converter that receives a voltage 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 above a predetermined level for driving the BMIC.

Description

Technology Field

[0001] The present disclosure relates to a battery system. Background Technology

[0002] A 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 may be performed to balance the voltage between the plurality of battery cells. The cell balancing operation may be implemented by discharging the current flowing through a battery cell with a deviation among the plurality of battery cells through a balancing load.

[0003] In addition, the battery monitoring integrated circuit that monitors the voltage of battery cells requires a power supply to perform voltage monitoring operations, and also requires a standby power supply even during periods when monitoring is not being performed. Therefore, a power supply is required to provide power to the battery monitoring integrated circuit. The problem to be solved

[0004] In a battery pack comprising multiple battery cells, the present invention aims to provide a battery system capable of supplying power to a battery monitoring integrated circuit using power consumed during cell balancing operations between multiple battery cells. means of solving the problem

[0005] A battery system according to one feature of the invention comprises: 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 a target battery cell requiring cell balancing among the plurality of battery cells; a power conversion unit including a DC-DC converter that receives a voltage 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 above a predetermined level for driving the BMIC.

[0006] If the output voltage is less than a predetermined level for driving the BMIC, the power supply unit can regulate the voltage supplied from the battery pack to a predetermined level of voltage for driving the BMIC and supply it to the BMIC.

[0007] It may further include a plurality of MUXs that connect a target battery cell requiring cell balancing among the plurality of battery cells to one of the plurality of balancing batteries.

[0008] The power conversion unit above can operate the DC-DC converter when the voltage output from the plurality of balancing batteries is above a predetermined threshold voltage.

[0009] The power conversion unit further includes an ADC that measures the voltage output from the plurality of balancing batteries and generates a voltage measurement signal, and based on the voltage measurement signal, the charging status of the plurality of balancing batteries by the target battery cell can be controlled.

[0010] While the above ADC measures the voltage output from the plurality of balancing batteries, the power converter may not operate.

[0011] It may further include a PTC element located on a current path in which any one of the plurality of balancing batteries is charged by cell balancing of the target battery cell.

[0012] When the plurality of balancing batteries are connected in parallel, a PTC element located on the current path between the plurality of balancing batteries may be further included.

[0013] The power supply unit may include a resistor connected to wiring connected to the battery pack, a capacitor in which a voltage generated using the voltage of the battery pack is charged, and a transistor in which a drive voltage supplied from the BMIC is input to the base terminal, the resistor is connected to the collector terminal, and the capacitor is connected to the emitter terminal, and which operates to supply a voltage generated from the voltage of the collector terminal to the BMIC when the voltage of the emitter terminal does not reach the voltage level of the base terminal.

[0014] In addition, a battery system according to another feature of the invention comprises 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 for receiving the plurality of cell voltages and determining a target battery cell among the plurality of battery cells that requires cell balancing, a plurality of balancing batteries that are charged by cell balancing, a MUX for connecting the determined target battery cell to one of the plurality of balancing batteries according to the control of the MCU, a DC-DC converter for converting the voltage input from the plurality of balancing batteries to generate an output voltage, and a power supply unit for supplying the higher voltage among the output voltage of the DC-DC converter and the voltage generated using the voltage of the battery pack to the BMIC.

[0015] The above DC-DC converter can operate when the voltage input from the plurality of balancing batteries is above a predetermined threshold voltage.

[0016] In addition, a battery system according to another feature of the invention comprises a plurality of battery packs each comprising a plurality of battery cells, for each of the plurality of battery packs, a plurality of slave BMSs for managing the battery packs - each of the plurality of slave BMSs includes a BMIC connected to a corresponding plurality of battery cells to measure a plurality of cell voltages and 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 that converts the voltage supplied from the plurality of balancing batteries to generate an output voltage, and a power supply unit that supplies the higher voltage among the output voltage of the DC-DC converter and the voltage generated using the voltage of the battery pack to the BMIC.

[0017] It may further include a master BMS that receives a voltage measurement signal from the plurality of slave BMSs that measures the voltage supplied from the plurality of balancing batteries, generates a control signal capable of controlling the plurality of slave BMSs based on the voltage measurement signal, and transmits the control signal to the plurality of slave BMSs.

[0018] When the voltage supplied from the plurality of balancing batteries is above a predetermined threshold voltage, the master BMS can generate a control signal including a control command to turn on the DC-DC converter. Effects of the invention

[0019] A battery system is provided that can supply power to a battery monitoring integrated circuit using power consumed in a cell balancing operation between multiple battery cells in a battery pack comprising multiple battery cells. By doing so, the power consumption of the battery system can be reduced. Brief explanation of the drawing

[0020] FIG. 1 is a schematic circuit diagram showing a battery system according to one embodiment. FIG. 2 is a diagram showing a MUX according to one embodiment. FIG. 3 is a drawing showing a balancing battery section according to one embodiment. Figure 4 is a diagram schematically showing the PTC section, power conversion section, and power supply section connected to each other. FIG. 5 is a schematic circuit diagram showing a battery system equipped with a current sensor according to one embodiment. FIG. 6 is an exemplary diagram schematically illustrating the connection relationship of a battery system connected to a plurality of battery packs according to one embodiment. FIG. 7 is a schematic circuit diagram showing one embodiment of the detailed configuration of the SBMS of FIG. 6. Specific details for implementing the invention

[0021] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components are assigned identical or similar reference numerals, and redundant descriptions thereof will be omitted. The suffixes "module" and / or "part" for components used in the following description are assigned or used interchangeably solely for the ease of drafting the specification and do not have distinct meanings or roles in themselves. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted. Additionally, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification; the technical concept disclosed in this specification is not limited by the attached drawings, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the invention.

[0022] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.

[0023] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0024] In a configuration that controls another configuration under specific control conditions among the configurations according to one embodiment, a program implemented as a set of instructions specifying a control algorithm required to control the other configuration may be installed. The control configuration may generate output data by processing input data and stored data according to the installed program. The control configuration may include a non-volatile memory for storing the program and a memory for storing data.

[0025] FIG. 1 is a schematic circuit diagram showing a battery system according to one embodiment.

[0026] Referring to FIG. 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 MUXs (40, 41), a balancing battery unit (50), a PTC unit (60), a power conversion unit (70), a power supply unit (80), and relays (90, 91). The battery monitoring integrated circuit is hereinafter referred to as a BMIC (Battery Monitoring Integrated Circuit). The main control unit is hereinafter referred to as an MCU (Main Control Unit).

[0027] The external device (2) may include a load and a charging device such as an inverter or a converter. If the external device (2) is a charger, both ends of the battery system (1) are connected to the charger so that power is supplied from the charger and charged. If the external device (2) is a load, both ends of the battery system (1) are connected to the load so that power supplied by the battery pack (10) can be discharged through the load.

[0028] The battery pack (10) includes a plurality of battery cells (11-16) connected in series. Although the battery pack (10) is illustrated in FIG. 1 as including six battery cells (11-16) connected in series, this is merely an example and the invention is not limited thereto. The battery pack (10) may be implemented with a plurality of battery cells connected in series, or two or more battery cells connected in parallel, and a plurality of battery cells connected in series.

[0029] Hereinafter, cell balancing described in this specification may refer to a charge equalization operation for a battery cell that is greater than or equal to a reference value among a plurality of battery cells (11-16) included in a battery pack (10). The reference value is a value set based on the cell voltage of a 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, etc. Conventional charge equalization operation may be implemented by transferring the charge stored in a cell requiring cell balancing to a battery cell with a low cell voltage, or by discharging the charge stored in a cell requiring cell balancing using a discharge load. However, according to one embodiment, the charge equalization operation may be implemented by transferring the charge stored in a cell requiring cell balancing to a balancing battery.

[0030] The power consumed by the BMIC (20) can be divided into monitoring power required for monitoring and standby power in a sleep state. Monitoring power is the power consumed by the BMIC (20) while performing monitoring. Standby power is the power consumed by the BMIC (20) in a sleep state when not performing monitoring. Since standby power is consumed during long-term transportation and storage, both monitoring power and standby power must be considered when calculating the power consumption of the BMIC (20). The charging energy of each of the multiple battery cells (11-16) may be reduced due to the power consumption of the BMIC (20).

[0031] Hereinafter, with reference to FIGS. 1 to 5, an embodiment is described in which a balancing battery is charged with energy generated from a charge equalization operation of a cell requiring cell balancing, and the power charged in the balancing battery is supplied to a BMIC (20).

[0032] The BMIC (20) is connected to each of the multiple battery cells (11-16) and obtains multiple voltage measurement signals (VS1-VS7) measured from both ends of the multiple battery cells (11-16) through multiple input terminals (P1-P7). The positive terminal of each of the multiple battery cells (11-16) (e.g., 11) is connected to a corresponding input terminal (e.g., P1) among the multiple input terminals (P1-P6) through wiring, and the negative terminal of each of the multiple battery cells (11-16) (e.g., 11) is connected to a corresponding input terminal (e.g., P2) among the multiple input terminals (P2-P7) through wiring. For example, the measurement signal (VS1) is the positive voltage of the battery cell (11) and is input to the BMIC (20) through the input terminal (P1), and the measurement signal (VS2) is the negative voltage of the battery cell (11) or the positive voltage of the battery cell (12) and is input to the BMIC (20) through the input terminal (P2).

[0033] The BMIC (20) can transmit a plurality of cell voltage signals to the MCU (30) indicating the cell voltages of a plurality of battery cells derived from a plurality of voltage measurement signals (VS1-VS7). For example, the BMIC (20) can generate a cell voltage signal based on the voltage obtained by subtracting the negative voltage from the positive voltage of each of the plurality of battery cells and transmit it to the MCU (30).

[0034] The MCU (30) receives a plurality of cell voltage signals and determines a battery cell (hereinafter, target battery cell) that requires cell balancing among a 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) through a plurality of MUXs (40, 41), and then controls the balancing battery unit (50) to be connected to the power conversion unit (70) through 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) through a corresponding MUX among the plurality of MUXs (40, 41), the corresponding balancing battery can be 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) into a voltage level suitable for driving the BMIC (20) and supply it to the BMIC (20).

[0035] For such control, the MCU (30) can generate multiple MUX control signals (MCS1, MCS2) and transmit them to multiple MUXs (40, 41), generate multiple switch control signals (SC1-SC4) and transmit them to the PTC unit (60), and transmit them to the power conversion unit (70) through the converter control signal (CCS). The MCU (30) controls whether to enable the power conversion unit (70) through the converter control signal (CCS) and can receive a battery signal (BS) generated from the battery ADC of the power conversion unit (70).

[0036] Each of the multiple MUXs (40, 41) can connect 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 MUXs (40, 41) refer to multiple battery cells connected to the corresponding MUX. In FIG. 1, it is shown that the MUX (40) is connected to three battery cells (11-13) and the MUX (41) is connected to three battery cells (14-16).

[0037] Each of the plurality of MUXs (40, 41) (e.g., 40) can connect the positive and negative electrodes of a target battery cell among the plurality of connected battery cells (e.g., 11-13) among the plurality of battery cells (11-16) to the corresponding wiring (101, 102) among the plurality of wirings (101-104). Although FIG. 1 shows that the number of plurality of MUXs (40, 41) is two, the invention is not limited thereto, and the battery system (1) may include one or more MUXs. The following description regarding the operation of the MUX (40) can be applied in the same way to the MUX (41).

[0038] The MUX (40) connects a target battery cell among a plurality of corresponding battery cells (11-13) to the balancing battery unit (50) according to a plurality of MUX control signals (MCS1). The MUX (41) connects a target battery cell among a plurality of corresponding battery cells (14-16) to the balancing battery unit (50) according 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).

[0039] One end of the relay (90, 91) is connected to the battery pack (10), and the other end of the relay (90, 91) is connected to at least one configuration in the external device (2). The closing and opening of the relay (90, 91) are controlled according to relay control signals (RSC1, RSC2) supplied from the MCU (30).

[0040] FIG. 2 is a diagram showing a MUX according to one embodiment.

[0041] When a target battery cell is determined among a plurality of battery cells (11-16), the MCU (30) generates a plurality of MUX control signals (MCS1, MCS2) to connect the target battery cell to the balancing battery unit (50).

[0042] As illustrated in FIG. 2, the MUX (40) includes a plurality of switching elements (411-416), and each of the plurality of switching signals (MS1-MS6) can control the switching operation of the corresponding switching element. When battery cell (11) among the plurality of battery cells (11-13) is the target battery cell, the MCU (30) generates switching signals (MS1, MS4) among the plurality of switching signals (MS1-MS6) to an ON level, and the switching elements (411, 414) can be turned on by the ON level switching signals (MS1, MS4). Then, the battery cell (11) can be connected to the balancing battery unit (50) through the MUX (40). At this time, an off-level switching signal (MS2, MS3, MS5, MS6) from the MCU (30) is supplied to a plurality of switching elements (412, 413, 415, 416) connected to a battery cell (12, 13) other than the target battery cell, and the plurality of switching elements (412, 413, 415, 416) may be in an off state.

[0043] MUX (41) also has the same configuration as MUX (40) and can operate in the same way.

[0044] 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, can be implemented through a circuit including a field effect transistor (FET) element instead of a MUX (40).

[0045] In the balancing battery section (50), the balancing battery can be charged by receiving energy from a target battery cell connected through wiring (101) and wiring (102).

[0046] FIG. 3 is a drawing showing a balancing battery section according to one embodiment.

[0047] The detailed configuration of the balancing battery unit (50) will be explained below with reference to FIG. 3.

[0048] The balancing battery unit (50) may include a plurality of balancing batteries (500, 501) and a plurality of PTC elements (510, 511).

[0049] In FIG. 1, the number of balancing batteries (500, 501) and the number of PTC elements (510, 511) are each shown as two, but the invention is not limited thereto, and the number of each can be increased or decreased based on the number of MUXs.

[0050] 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). A PTC element (510) may be formed on the wiring (101). Unlike the one shown in FIG. 3, the PTC element (510) may be formed on the wiring (102). The PTC element (510) may be implemented as a resistor having a positive temperature coefficient. When the balancing battery (500) is connected to a target battery cell among a 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, thereby limiting the charging current. For example, the resistance of the PTC element (510) may rapidly increase due to heat generated during a short circuit, thereby blocking the current flowing through the wiring (101).

[0051] The positive terminal of the balancing battery (501) is connected to the wiring (103), and the negative terminal of the balancing battery (501) is connected to the wiring (104). A PTC element (511) may be formed on the wiring (103). Unlike the one shown in FIG. 3, the PTC element (511) may be formed on the wiring (104). The PTC element (511) may be implemented as a resistor having a positive temperature coefficient. When the balancing battery (501) is connected to a target battery cell among a 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, thereby limiting the charging current. For example, the resistance of the PTC element (511) may rapidly increase due to heat generated during a short circuit, thereby blocking the current flowing through the wiring (103).

[0052] The detailed configuration of the PTC unit (60), power conversion unit (70), and power supply unit (80) will be explained below with reference to FIG. 4.

[0053] Figure 4 is a diagram schematically showing the PTC section, power conversion section, and power supply section connected to each other.

[0054] The PTC unit (60) includes four switches (601-604) and a PTC element (600).

[0055] A switch (601) is connected between wiring (105) and wiring (110) and controls the connection between the balancing battery (500) and the input terminal (P71) of the DC-DC converter (700) by switching operation by a switch control signal (SC1). A switch (602) is connected between wiring (106) and wiring (109) and controls the connection between the balancing battery (500) and the input terminal (P72) of the DC-DC converter (700) by switching operation by a switch control signal (SC2). A switch (603) is connected between wiring (107) and wiring (110) and controls the connection between the balancing battery (501) and the input terminal (P71) of the DC-DC converter (700) by switching operation by a switch control signal (SC3). The switch (604) is connected between the wiring (108) and the wiring (109) and controls the connection between the balancing battery (500) and the input terminal (P72) of the DC-DC converter (700) by switching operation by the switch control signal (SC4).

[0056] The ON level of the multiple switch control signals (SC1-SC4) may be a high level, and the OFF level may be a low level. That is, the switch (601-604) may be turned on according to the high level switch control signal (SC1-SC4), and the switch (601-604) may be turned off according to the low level switch control signal (SC1-SC4).

[0057] While the balancing battery (500) is being charged by the target battery cell through the wiring (101) and wiring (102), the plurality of switches (601, 602) may be turned off by the plurality of low-level switch control signals (SC1, SC2). While the balancing battery (501) is being charged by the target battery cell through the wiring (103) and wiring (104), the plurality of switches (603, 604) may be turned off by the plurality of low-level switch control signals (SC3, SC4).

[0058] After the balancing operation is finished, the multiple switches (601-604) can be turned on by the multiple switch control signals (SC1-SC4) at a high level.

[0059] When multiple switches (601-604) are turned on, the positive terminal of the balancing battery (500) is connected to the input terminal (P71) of the DC-DC converter (700) through wiring (105, 110), the negative terminal of the balancing battery (500) is connected to the input terminal (P72) of the DC-DC converter (700) through wiring (106, 109), the positive terminal of the balancing battery (501) is connected to the input terminal (P71) of the DC-DC converter (700) through wiring (107, 110), and the negative terminal of the balancing battery (501) is connected to the input terminal (P72) of the DC-DC converter (700) through wiring (108, 109).

[0060] When a plurality of switches (601-604) are turned on, balancing between the plurality of balancing batteries (500, 501) may occur due to the potential difference between the plurality of balancing batteries (500, 501). The PTC unit (60) may include a PTC element (600) to limit the balancing between the plurality of balancing batteries (500, 501).

[0061] A PTC element (600) may be formed on the current path between the balancing batteries (500, 501). In FIG. 4, the PTC element (600) is formed on the wiring (105). Unlike what is shown in FIG. 4, the PTC element (600) may be formed on the wiring (107). When all of the multiple switches (601-604) are in the ON state, a balancing current may flow 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, as the balancing current increases, its resistance increases, thereby limiting the balancing current. If a short circuit occurs due to the balancing current, the resistance of the PTC element (600) increases rapidly, thereby blocking the balancing current.

[0062] The power conversion unit (70) includes a DC-DC converter (700) and an analog-digital converter (ADC) (710).

[0063] The ADC (710) can receive the voltage of each of the multiple balancing batteries (500, 501) through the wiring (110) and transmit the generated battery voltage measurement signal (BS) to the MCU (30). The MCU (30) checks the voltage of each of the balancing batteries (500, 501) after balancing through the voltage measurement signal (BS) received from the ADC (710) and controls the multiple MUXs (40, 41) so that each balancing battery (500, 501) does not become an overvoltage state. For example, if at least one of the balancing batteries (500, 501) is in an overvoltage state, the MCU (30) can keep the multiple MUX control signals (MCS1, MCS2) off level even if there is a battery cell among the multiple battery cells (11-16) that requires balancing, and discharge the target battery cell through another cell balancing circuit, for example, a passive cell balancing circuit.

[0064] While measuring the voltage of the balancing battery (500, 501), the MCU (30) can stop the operation of the DC-DC converter (700) by supplying an off-level voltage to the hold terminal (720) through the converter control signal (CCS).

[0065] The hold terminal (720) is connected to the contact between two resistors (R1, 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, if the voltage of the hold terminal (720) drops below a predetermined threshold voltage, the DC-DC converter (700) may not operate. The voltage of the hold terminal (720) may be the voltage at which the input terminal (P71) voltage of the DC-DC converter (700) is distributed to the enable pin (P70) by the two resistors (R1, R2). A voltage at the hold terminal (720) dropping below a predetermined threshold voltage may indicate that the voltage at the input terminal (P71) has dropped below a predetermined threshold value.

[0066] Alternatively, the MCU (30) may operate the DC-DC converter (700) by supplying an ON-level converter control signal (CCS) to the hold terminal (720). Additionally, the MCU (30) may stop the operation of the DC-DC converter (700) by supplying an OFF-level converter control signal (CCS) to the hold terminal (720). In this case, the voltage of the hold terminal (720) may not follow the voltage supplied from the balancing battery unit (50).

[0067] The power conversion unit (70) can maintain the output voltage of the DC-DC converter (700) at a predetermined level by means of the hold terminal (720). Here, the predetermined level may be a normal level capable of driving the BMIC (20).

[0068] The power supply unit (80) operates according to the drive voltage supplied from the terminal (P8) of the BMIC (20) through the wiring (112), and regulates the voltage supplied from the battery pack (10) through the wiring (113) to a power voltage level suitable for the BMIC (20) and supplies it to the terminal (P9) of the BMIC (20).

[0069] 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) may 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).

[0070] 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 wire (113) connected to the positive terminal of the battery pack (10), and the other end of the resistor (R) is connected to the collector terminal of the transistor (Q1). The emitter terminal of the transistor (Q1) is connected to one end of the capacitor (C), and the other end of the capacitor (C) is connected to ground. A drive voltage supplied from the BMIC (20) is input to the base terminal of the transistor (Q1). The BMIC (20) receives the voltage charged in the capacitor (C) of the power supply unit (80) as the power supply voltage, and can regulate the power supply voltage by controlling the switching operation of the transistor (Q1) according to the level of the power supply voltage.

[0071] The output terminal of the DC-DC converter (700) is connected to the contact between the emitter terminal of the transistor (Q1) and one end of the capacitor (C) via 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 greater than the drive 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 the power 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 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 supplied to the BMIC (20) as is via wiring (111). Additionally, 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) can operate. Then, instead of the output voltage of the DC-DC converter (700), a power supply voltage is supplied from the power supply unit (80) to the BMIC (20). Accordingly, 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) as the power supply voltage to the BMIC (20).

[0072] FIG. 5 is a schematic circuit diagram showing a battery system equipped with a current sensor according to one embodiment.

[0073] Referring to FIG. 5, the battery system (1) may be equipped with current sensors (51, 52) between a plurality of MUXs (40, 41) and a balancing battery unit (50).

[0074] The battery system (1000) of FIG. 5 can be seen as identical to the battery system (1) of FIG. 1 except that a current sensor (51) is added, and redundant descriptions are omitted.

[0075] The current sensor (51) can check the amount of current flowing through the wiring connecting the target battery cell and the balancing battery (500, 501). In FIG. 5, the current sensor (51) is shown as being provided on the wiring (101) and the current sensor (52) is shown as being provided on the wiring (103), but the invention is not limited thereto and may be provided on at least one of the wiring (101-104) connecting the target battery cell and the balancing battery. The current sensors (51, 52) may be implemented as Hall sensors. The current sensors (51, 52) can measure the current flowing through the wiring (101, 103), generate a current measurement signal (not shown), and transmit it to the MCU (30). The MCU (30) can detect the charging current of the balancing battery (500, 501) based on the received current measurement signal, estimate the charge amount of the balancing battery (500, 501), or detect overcurrent and control the protection operation.

[0076] Hereinafter, with reference to FIGS. 6 and FIGS. 7, a case in which a plurality of battery packs are included in the battery system will be described.

[0077] FIG. 6 is an exemplary diagram schematically illustrating the connection relationship of a battery system connected to a plurality of battery packs according to one embodiment.

[0078] 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). Each of the plurality of battery packs (100, 200, 300) is illustrated as including six battery cells connected in series, but this is merely an example and the invention is not limited thereto. Each of the plurality of battery packs (100, 200, 300) may be implemented as a plurality of battery cells, such as two or more battery cells connected in series, or two or more battery cells connected in parallel, with multiple battery cells connected in series. In FIG. 6, the battery system (2000) is illustrated as including three battery packs (100, 200, 300) connected in series, but this is merely an example and the invention is not limited thereto. The battery system (2000) may include two or more battery packs.

[0079] Referring to FIG. 6, when a battery system includes a plurality of battery packs (100, 200, 300), a corresponding SBMS (22) among a plurality of SBMSs (22-24) is connected to each of the plurality of battery packs (100, 200, 300) (e.g., 100). Each of the plurality of SBMSs (22-24) (e.g., 22) is connected to each of the plurality of battery cells of the corresponding battery pack (e.g., 100).

[0080] The MBMS (21) can perform the functions performed by the MCU (30) of the embodiment shown in FIGS. 1 and FIG. 5. A plurality of SBMSs (22-24) can measure information necessary for managing the battery system (2000) (e.g., a plurality of cell voltages, the temperature of the battery pack, etc.) and send a signal indicating the measurement results to the MBMS (21) via wired or wireless communication. FIG. 6 is illustrated as the MBMS (21) and a plurality of SBMSs (22-24) being connected to each other in a daisy chain structure, but this is merely an example and the invention is not limited thereto, and the MBMS (21) and a plurality of SBMSs (22-24) can be connected to each other directly or indirectly and communicate via wired or wireless communication.

[0081] FIG. 7 is a schematic circuit diagram illustrating an example of the detailed configuration of the SBMS of FIG. 6. Although the BMS (22) of FIG. 7 is depicted as relating to one of the plurality of SBMSs (22-24) of FIG. 6, it can be applied equally to each of the plurality of SBMSs (22-24).

[0082] The operation in which the MCU (30) controls a plurality of MUXs (40, 41), a PTC unit (60), and a power conversion unit (70) in the battery system (1, 1000) illustrated in FIG. 1 and 5 can be implemented by the MBMS (31) controlling a plurality of MUXs (40, 41), a PTC unit (60), and a power conversion unit (70) in the battery system (2000) of FIG. 7.

[0083] The BMIC (220) can generate a slave signal (SS) including the voltage of multiple cells (1001-1006), the temperature of the battery pack (100), and a battery signal (BS) received from the battery ADC of the power conversion unit (70), and transmit it to the MBMS (21).

[0084] The MBMS (21) can generate a control signal (CS) capable of controlling the plurality of SBMSs (22-24) based on slave signals (SS) received from the plurality of SBMSs (22-24). The MBMS (21) can transmit the generated control signal (CS) to the plurality of SBMSs (22-24). The control signal (CS) may include a plurality of MUX control signals (MCS1-MCS2), a plurality of switch control signals (SC1-SC4), and a converter control signal (CCS).

[0085] The MBMS (21) can determine a target battery cell that requires cell balancing among a plurality of battery cells (1001-1006), control a plurality of MUXs (40, 41) so that the target battery cell is connected to the balancing battery unit (50) through a plurality of MUXs (40, 41), then control it to be connected to the power conversion unit (70) through the PTC unit (60), and control the power conversion unit (70) to supply power to the BMIC (220). The MBMS (21) can generate a signal (CS) containing a control command for such control and transmit it to the SBMS (22). MBMS (21) can generate control commands corresponding to each SBMS (22) as well as SBMS (23, 24) in the same way, and generate a signal (CS) containing control commands corresponding to multiple SBMS (22-24) and transmit it to multiple SBMS (22-24).

[0086] BMIC (220) can generate multiple MUX control signals (MCS1, MCS2) according to the signal (CS) received from MBMS (21) and transmit them to multiple MUXs (40, 41), generate multiple switch control signals (SC1-SC4) and transmit them to the PTC unit (60), and transmit them to the power conversion unit (70) through the converter control signal (CCS). BMIC (220) can control whether to enable the power conversion unit (70) through the converter control signal (CCS).

[0087] When a target battery cell is connected to a corresponding balancing battery of the balancing battery unit (50) through a corresponding MUX among a plurality of MUXs (40, 41), the corresponding balancing battery can be 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) into a voltage level suitable for driving the BMIC (220) and supply it to the BMIC (220).

[0088] For example, the MBMS (21) may transmit a control signal (CS) to the BMIC (220) that includes a control command to enable the power conversion unit (70) so that the BMIC (220) can receive power from the power conversion unit (70) when the input voltage input to the power conversion unit (70) of the SBMS (22) according to the slave signal (SS) is greater than or equal to a predetermined voltage. The BMIC (220) may generate a converter control signal (CCS) that enables the power conversion unit (70) according to the control signal (CS) and transmit it to the power conversion unit (70).

[0089] Additionally, if at least one of the multiple balancing batteries included in the balancing battery section (50) of the SBMS (22) is in an overvoltage state according to the slave signal (SS) of the MBMS (21), the BMIC (220) can transmit a control signal (CS) containing a control command that prevents the BMIC (220) from operating the multiple MUXs (40, 41). According to the control signal (CS), the BMIC (220) can generate multiple MUX control signals (MCS1, MCS2) of an off level that keep the multiple MUXs (40, 41) in an off state, even if there are battery cells among the multiple battery cells (1001-1006) that require balancing, and transmit them to the multiple MUXs (40, 41).

[0090] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modified and improved forms by those skilled in the art to which the present invention pertains also fall within the scope of the present invention. Explanation of the symbols

[0091] 1, 1000, 2000: Battery System 2 : External device 10, 100, 200, 300: Battery pack 11, 12, 13, 14, 15, 16, 1001, 1002, 1003, 1004, 1005, 1006: Battery cells 20, 220 : Battery monitoring integrated circuit 21: Master Battery Management System 22, 23, 24: Slave battery management system 30: Main control unit 40, 41 : MUX 411, 412, 413, 414, 415, 416: Switching elements 50: Balancing Battery Section 500, 501: Balancing Battery 510, 511: PTC element 60 : PTC section 600 : PTC element 601, 602, 603, 604 : Switch 70: Power converter 700 : DC-DC converter 710 : ADC 720 : Hold terminal 80: Power supply 90, 91: Relay 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113 : Wiring

Claims

Claim 1 A battery system comprising: a battery pack including a plurality of battery cells; a BMIC for monitoring a plurality of cell voltages for each of the plurality of battery cells; a plurality of balancing batteries charged by a target battery cell requiring cell balancing among the plurality of battery cells; a power conversion unit including a DC-DC converter that receives a voltage 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 above a predetermined level for driving the BMIC. Claim 2 A battery system according to claim 1, wherein the power supply unit, when the output voltage is less than a predetermined level for driving the BMIC, regulates the voltage supplied from the battery pack to a predetermined level voltage for driving the BMIC and supplies it to the BMIC. Claim 3 A battery system according to claim 1, further comprising a plurality of MUXs for connecting a target battery cell requiring cell balancing among the plurality of battery cells to one of the plurality of balancing batteries. Claim 4 In claim 1, the power conversion unit operates the DC-DC converter when the voltage output from the plurality of balancing batteries is greater than or equal to a predetermined threshold voltage, in a battery system. Claim 5 A battery system according to claim 1, wherein the power converter further includes an ADC that measures the voltage output from the plurality of balancing batteries and generates a voltage measurement signal, and the charging status of the plurality of balancing batteries by the target battery cell is controlled based on the voltage measurement signal. Claim 6 A battery system according to claim 5, wherein the power converter does not operate while the ADC measures the voltage output from the plurality of balancing batteries. Claim 7 A battery system according to claim 1, further comprising a PTC element located on a current path in which any one of the plurality of balancing batteries is charged by cell balancing of the target battery cell. Claim 8 A battery system according to claim 1, wherein, when the plurality of balancing batteries are connected in parallel, the battery system further comprises a PTC element located on a current path between the plurality of balancing batteries. Claim 9 A battery system according to claim 1, wherein the power supply unit comprises: a resistor connected to wiring connected to the battery pack; a capacitor charged with a voltage generated using the voltage of the battery pack; and a transistor in which a drive voltage supplied from the BMIC is input to the base terminal, the resistor is connected to the collector terminal, and the capacitor is connected to the emitter terminal, and which operates to supply a voltage generated from the voltage of the collector terminal to the BMIC when the voltage of the emitter terminal does not reach the voltage level of the base terminal. Claim 10 A battery system comprising: 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 for receiving the plurality of cell voltages and determining a target battery cell among the plurality of battery cells that requires cell balancing; a plurality of balancing batteries charged by cell balancing; a MUX for connecting the determined target battery cell to one of the plurality of balancing batteries according to the control of the MCU; a DC-DC converter for converting a voltage input from the plurality of balancing batteries to generate an output voltage; and a power supply unit for supplying the higher voltage among the output voltage of the DC-DC converter and the voltage of the battery pack to the BMIC. Claim 11 In claim 10, the above DC-DC converter is a battery system that operates when the voltage input from the plurality of balancing batteries is above a predetermined threshold voltage. Claim 12 A battery system comprising: a plurality of battery packs, each comprising a plurality of battery cells; for each of the plurality of battery packs, a plurality of slave BMSs for managing the battery packs, wherein each of the plurality of slave BMSs includes a BMIC connected to a corresponding plurality of battery cells to measure a plurality of cell voltages and 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 a voltage supplied from the plurality of balancing batteries to generate an output voltage; and a power supply unit for supplying the higher voltage among the output voltage of the DC-DC converter and the voltage generated using the voltage of the battery pack to the BMIC. Claim 13 A battery system according to claim 12, further comprising a master BMS that receives a voltage measurement signal from the plurality of slave BMSs that measures the voltage supplied from the plurality of balancing batteries, and generates a control signal capable of controlling the plurality of slave BMSs based on the voltage measurement signal and transmits it to the plurality of slave BMSs. Claim 14 A battery system according to claim 13, wherein when the voltage supplied from the plurality of balancing batteries is above a predetermined threshold voltage, the master BMS generates a control signal including a control command to turn on the DC-DC converter.

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