Battery management system

Abstract

This BMS (1) for managing a battery assembly comprises a BMU (201) that manages the battery assembly, and a plurality of CMUs (101, etc.) that monitor the battery assembly. One CMU (101) from among the plurality of CMUs (101, etc.) has a wireless communication circuit (111) and a timer circuit. The one CMU (101) repeatedly transitions, using a timing at which the timer circuit times out, between a first state in which electric power is supplied to the wireless communication circuit (111), whereby the wireless communication circuit (111) can receive a startup signal transmitted by the BMU (201), and a second state in which electric power is not supplied to the wireless communication circuit (111).

Description

Battery Management System

[0001] The present disclosure relates to a battery management system for managing a battery pack.

[0002] There is a battery management system that manages a battery pack including a plurality of battery cells. The battery management system includes a plurality of monitoring circuits that monitor the current or voltage of the battery cells, and a management circuit that manages the battery pack using the plurality of monitoring circuits (see, for example, Patent Document 1).

[0003] U.S. Pat. No. 1,524,588

[0004] A problem with battery management systems is that the management or monitoring circuits require a relatively large amount of power to operate.

[0005] The present disclosure is intended to solve such problems, and aims to provide a battery management system and the like that contributes to reducing the power consumption required for processing to manage a battery pack.

[0006] The battery management system according to the present disclosure is a battery management system for managing an assembled battery, and includes a management circuit for managing the assembled battery and a plurality of monitoring circuits for monitoring the assembled battery, one of the plurality of monitoring circuits having a wireless communication circuit and a timer circuit, and repeatedly transitioning between a first state in which the wireless communication circuit is powered and can receive an activation signal transmitted by the management circuit, and a second state in which the wireless communication circuit is not powered, using the timing when the timer circuit times out.

[0007] These comprehensive or specific aspects may be realized as a system, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized as any combination of a system, a method, an integrated circuit, a computer program, and a recording medium.

[0008] According to the present disclosure, the battery management system contributes to reducing the power consumption required for processing to manage the battery pack.

[0009] 1 is an external view showing an example of a battery management system according to a first embodiment. FIG. 2 is a configuration diagram showing an example of a battery management system according to the first embodiment. FIG. 3 is a configuration diagram showing an example of a wireless communication circuit included in a cell monitoring circuit according to the first embodiment. FIG. 4 is a configuration diagram showing an example of a voltage monitoring circuit included in a cell monitoring circuit according to the first embodiment. FIG. 5 is a configuration diagram showing an example of a current measurement circuit included in a current monitoring circuit according to the first embodiment. FIG. 6 is a configuration diagram showing an example of a wireless communication circuit included in a management circuit according to the first embodiment. FIG. 7 is a configuration diagram showing an example of an MCU included in a management circuit according to the first embodiment. FIG. 8 is an explanatory diagram showing state transitions of a cell monitoring circuit according to the first embodiment. FIG. 9 is an explanatory diagram showing presence or absence of power supply to each circuit in states that the cell monitoring circuit according to the first embodiment can take. FIG. 10 is an explanatory diagram showing transitions between a sleep state and an RF active state of a cell monitoring circuit according to the first embodiment. FIG. 11 is a configuration diagram showing an example of a wireless communication circuit included in a cell monitoring circuit according to a first modification of the first embodiment. FIG. 12 is a configuration diagram showing an example of a voltage monitoring circuit included in a cell monitoring circuit according to a second modification of the first embodiment. FIG. 13 is a configuration diagram showing a first example of a battery management system according to a first modification of the second embodiment. FIG. 10 is an explanatory diagram showing the impedance of a power line in a battery management system according to a second modification of the second embodiment.

[0010] (Foundation of the Present Disclosure) There is a battery management system that manages a battery pack including a plurality of battery cells. The battery pack is used, for example, as a battery for an electric vehicle.

[0011] The battery management system includes multiple monitoring circuits that monitor the current or voltage of the battery cells, and a management circuit that manages the assembled battery using the multiple monitoring circuits. The monitoring circuits include a current monitoring circuit that monitors the current flowing through the battery cells, and a cell monitoring circuit that monitors the voltage of the battery cells.

[0012] A problem with battery management systems is that the management or monitoring circuits require a relatively large amount of power to operate.

[0013] The present disclosure is intended to solve such problems, and aims to provide a battery management system and the like that contributes to reducing the power consumption required for processing to manage a battery pack.

[0014] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0015] The embodiments described below are all comprehensive or specific examples, and the numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0016] (First Embodiment) In this embodiment, a battery management system that contributes to reducing the power consumption required for processing to manage a battery pack will be described.

[0017] FIG. 1 is an external view showing an example of a battery management system 1 (hereinafter also referred to as a BMS (Battery Management System) 1) according to this embodiment.

[0018] The BMS 1 is a system for managing an assembled battery. For example, the BMS 1 manages the SOC (State of Charge), SOH (State of Health), and SOP (State of Power) of the assembled battery. The BMS 1 also monitors abnormalities in the assembled battery. The BMS 1 includes a management circuit 200 that manages the assembled battery and multiple monitoring circuits 100 that monitor the assembled battery. For example, the assembled battery is configured by connecting multiple battery packs 10 in series or parallel. The battery pack 10 is also configured by one or more battery cells. When the battery pack 10 is configured by multiple battery cells, the multiple battery cells are connected in series.

[0019] For example, the monitoring circuit 100 is disposed on each of the plurality of battery packs 10. A CMU (Cell Monitoring Unit) 101 and a CMU (Current Monitoring Unit) 301, which are specific examples of the monitoring circuit 100, will be described later.

[0020] For example, the management circuit 200 is connected to the battery pack via a junction box 20. A BMU (Battery Management Unit) 201, which is a specific example of the management circuit 200, will be described later.

[0021] FIG. 2 is a configuration diagram showing an example of the BMS 1 according to this embodiment.

[0022] 3 is a configuration diagram showing an example of the wireless communication circuit 111 included in the first cell monitoring circuit (CMU 101). Note that Fig. 3 also shows the peripheral parts of the wireless communication circuit 111 in the configuration diagram of Fig. 2.

[0023] 4 is a configuration diagram showing an example of the voltage monitoring circuit 112 included in the first cell monitoring circuit (CMU 101). Note that Fig. 4 also shows the peripheral parts of the voltage monitoring circuit 112 in the configuration diagram of Fig. 2.

[0024] 5 is a configuration diagram showing an example of the current measurement circuit 311 provided in the current monitoring circuit (CMU 301). Note that Fig. 5 also shows the peripheral parts of the current measurement circuit 311 in the configuration diagram of Fig. 2.

[0025] 6 is a block diagram showing an example of the wireless communication circuit 211 included in the management circuit (BMU 201). Note that Fig. 6 also shows the peripheral parts of the wireless communication circuit 211 in the block diagram of Fig. 2.

[0026] 7 is a block diagram showing an example of the MCU 212 included in the management circuit (BMU 201). Note that Fig. 7 also shows the peripheral parts of the MCU 212 in the block diagram of Fig. 2.

[0027] 2 focuses on one battery pack 10 out of multiple battery packs 10. As one or more battery cells that make up the battery pack, multiple battery cells 11 that make up one battery pack 10 in the battery pack are shown in FIG. 2. A CMU 101 is shown as the monitoring circuit 100, and a BMU 201 is shown as the management circuit 200. A motor 400 is shown as a load to which power is supplied from the battery pack, along with a power line 405 (bus bar) that connects the battery pack and the motor 400, and a relay 401 and a shunt resistor 402 inserted in the power line 405.

[0028] The relay 401 is a switch for interrupting the current flowing through the power line 405. For example, when the current monitored by the CMU 301 is determined to be abnormal, the relay 401 is turned off to interrupt the current flowing through the power line 405. Furthermore, for example, when the voltage monitored by the CMU 101 is determined to be abnormal, the relay 401 is turned off to interrupt the current flowing through the power line 405.

[0029] The shunt resistor 402 is a resistor for measuring the current flowing through the power line 405 .

[0030] The CMU 101 is an example of a cell monitoring circuit that monitors one or more battery cells that make up the battery pack. For example, the CMU 101 monitors the voltage of each of the plurality of battery cells 11.

[0031] 2, the CMU 101 includes a wireless communication circuit 111 and a communication antenna ANT1 for communicating with the BMU 201. The CMU 101 also includes a voltage monitoring circuit 112 that monitors the voltages of the multiple battery cells 11. For example, the wireless communication circuit 111 and the voltage monitoring circuit 112 are implemented by different integrated circuits (ICs). Alternatively, the wireless communication circuit 111 and the voltage monitoring circuit 112 may be implemented by a single IC.

[0032] As shown in FIG. 3 , the wireless communication circuit 111 includes a voltage conversion circuit (Reg.) 121, a timer circuit (Timer) 122, a communication interface (Com. I / F) 123, a clock generation circuit (Clock gen) 124, a phase-locked loop (PLL) 125, a modulation circuit (Modulator) 126, a transmission circuit (Tx) 127, a demodulation circuit (Demodulator) 128, a reception circuit (Rx) 129, a communication error determination circuit (RF Error) 131, and a wake-up circuit (Wake up) 132.

[0033] The voltage conversion circuit 121 is a circuit that converts the voltage input from the voltage monitoring circuit 112 into a voltage for operating the wireless communication circuit 111 and outputs the voltage.

[0034] The timer circuit 122 is a circuit that counts time. For example, the timer circuit 122 is used to cause the wireless communication circuit 111 to operate intermittently.

[0035] The communication interface 123 is an interface for communication between the wireless communication circuit 111 and the voltage monitoring circuit 112. Identification information "ID2A" is associated with the communication interface 123. The identification information of the communication interface 123 may be stored in any memory included in the wireless communication circuit 111. If the wireless communication circuit 111 and the voltage monitoring circuit 112 are implemented by a single IC, the communication interface 123 may not be provided.

[0036] The clock generation circuit 124 is a circuit for generating a clock in the CMU 101 .

[0037] The phase synchronization circuit 125 is a circuit that adjusts the phase of the local signal so that it coincides with the phase of the received signal.

[0038] The modulation circuit 126 is a circuit that modulates the signal to be transmitted to the BMU 201 .

[0039] The transmission circuit 127 is a circuit for transmitting a signal to the BMU 201. The transmission circuit 127 transmits the signal to the BMU 201 via the communication antenna ANT1.

[0040] The demodulation circuit 128 is a circuit that demodulates the signal received from the BMU 201 .

[0041] The receiving circuit 129 is a circuit for receiving a signal from the BMU 201. The receiving circuit 129 receives a signal from the BMU 201 via the communication antenna ANT1.

[0042] The communication error determination circuit 131 is a circuit that determines whether or not an abnormality has occurred in the communication between the CMU 101 and the BMU 201 .

[0043] The startup circuit 132 is a circuit for starting up the voltage monitoring circuit 112. The startup circuit 132 is connected to the encryption circuit 147 of the voltage monitoring circuit 112 and starts up the voltage monitoring circuit 112 by transmitting a startup signal.

[0044] As shown in FIG. 4, the voltage monitoring circuit 112 includes a voltage conversion circuit (Reg.) 141, a timer circuit (Timer) 142, a multiplexer (MUX) 143, an AD converter (ADC) 144, a communication interface (Com. I / F) 145, a phase-locked loop (PLL) 146, an encryption circuit (Encryption) 147, and a switch 148.

[0045] The voltage conversion circuit 141 is a circuit that converts the voltage input from the battery pack into a voltage for operating the voltage monitoring circuit 112 and the wireless communication circuit 111 and outputs the converted voltage.

[0046] The timer circuit 142 is a circuit that counts time. The timer circuit 142 is connected to the switch 148. The timer circuit 142 is a circuit for intermittently operating the wireless communication circuit 111. The timer circuit 142 turns on the switch 148 by transmitting a control signal that turns on the switch 148 when a set time has elapsed (also referred to as a timeout). After transmitting the control signal that turns on the switch 148, the timer circuit 142 turns off the switch 148 by transmitting a control signal that turns off the switch 148 when the set time has elapsed.

[0047] The multiplexer 143 selects one battery cell 11 from the plurality of battery cells 11 and outputs the voltage across the selected battery cell 11. In other words, the multiplexer 143 can output the voltages of the plurality of battery cells 11.

[0048] The AD converter 144 converts the voltage value (analog value) of the battery cell 11 selected by the multiplexer 143 into a digital value.

[0049] The communication interface 145 is an interface for communication between the wireless communication circuit 111 and the voltage monitoring circuit 112. Note that if the wireless communication circuit 111 and the voltage monitoring circuit 112 are implemented by a single IC, the communication interface 145 does not need to be provided.

[0050] The phase synchronization circuit 146 is a circuit that adjusts the phase of the local signal so that it coincides with the phase of the received signal.

[0051] The encryption circuit 147 is a circuit that encrypts and decrypts signals. For example, the encryption circuit 147 encrypts signals to be transmitted to the wireless communication circuit 111 and eventually to the BMU 201 using an encryption key.

[0052] The switch 148 is a switch, such as a transistor, that switches on and off the supply of power to the wireless communication circuit 111. The on and off of the switch 148 can be controlled by a control signal from the timer circuit 142.

[0053] The CMU 101 detects the voltage values ​​of each of the plurality of battery cells 11 using the voltage monitoring circuit 112 , and transmits the detected voltage values ​​to the BMU 201 using the wireless communication circuit 111 .

[0054] 2, the CMU 301 includes a current measurement circuit 311 that monitors the current flowing through the battery pack, a power supply circuit 312, and an insulated communication circuit 313.

[0055] The power supply circuit 312 is a circuit for supplying power to the CMU 301, and supplies the power supplied from the BMU 201 to the CMU 301. For example, the power supply circuit 312 is supplied with power from the BMU 201 via a transformer 501.

[0056] The insulated communication circuit 313 is a circuit for performing communication between the CMU 301 and the BMU 201 while the CMU 301 and the BMU 201 are insulated from each other. For example, by using a transformer 502, the insulated communication circuit 313 can perform communication between the CMU 301 and the BMU 201 while the CMU 301 and the BMU 201 are insulated from each other.

[0057] The current measurement circuit 311 is a circuit that measures the current flowing through the battery pack. Specifically, the current measurement circuit 311 measures the voltage generated when a current flows through a shunt resistor 402 provided on the power line 405, thereby measuring the current flowing through the power line 405, i.e., the current flowing through the battery pack. As shown in Fig. 5 , the current measurement circuit 311 includes an amplifier circuit 321, an AD converter (ADC) 322, and a communication interface (Com. I / F) 323.

[0058] The amplifier circuit 321 amplifies the voltage generated across the shunt resistor 402. The resistance value of the shunt resistor 402 is very small, and the voltage generated across the shunt resistor 402 is also small, so the amplifier circuit 321 is provided.

[0059] The AD converter 322 converts the value (analog value) of the voltage generated across the shunt resistor 402 into a digital value.

[0060] The communication interface 323 is an interface for communication between the CMU 301 and the BMU 201 .

[0061] 2 , the BMU 201 includes a wireless communication circuit 211 and a communication antenna ANT2 for communicating with the CMU 101. The BMU 201 also includes an MCU (Micro Controller Unit) 212 and a CAN (Controller Area Network) interface 213 for managing the battery pack. The wireless communication circuit 211 and the MCU 212 may be implemented by a single IC (e.g., a single MCU). The BMU 201 also includes a power supply circuit 215 and an insulated communication circuit 216.

[0062] The CAN interface 213 is a communication interface that is connected to a CAN provided in a vehicle in which the battery pack is mounted.

[0063] The power supply circuit 215 is a circuit for supplying power to the CMU 301. For example, the power supply circuit 215 supplies power to the CMU 301 via a transformer 501.

[0064] The insulated communication circuit 216 is a circuit for performing communication between the CMU 301 and the BMU 201 while the CMU 301 and the BMU 201 are insulated from each other. For example, by using a transformer 502, the insulated communication circuit 216 can perform communication between the CMU 301 and the BMU 201 while the CMU 301 and the BMU 201 are insulated from each other.

[0065] CMU 301 monitors the current flowing through a battery pack with a large voltage of several hundred volts and handles large voltages, whereas BMU 201 handles a voltage of about several volts. Therefore, CMU 301 and BMU 201 are insulated by being connected via transformers 501 and 502.

[0066] As shown in Fig. 6, the wireless communication circuit 211 includes a voltage conversion circuit (Reg.) 221, a timer circuit (Timer) 222, a communication interface (Com. I / F) 223, a clock generation circuit (Clock gen) 224, a phase-locked loop (PLL) 225, a modulation circuit (Modulator) 226, a transmission circuit (Tx) 227, a demodulation circuit (Demodulator) 228, a reception circuit (Rx) 229, a communication error determination circuit (RF Error) 231, and a wake-up circuit (Wake up) 232. Also, Fig. 6 shows "ID0A" as identification information for the wireless communication circuit 211. The identification information for the communication interface 223 may be stored in any memory included in the wireless communication circuit 211.

[0067] The voltage conversion circuit 221 is a circuit that converts a voltage input from an arbitrary power source into a voltage for operating the wireless communication circuit 211 and outputs the voltage.

[0068] The timer circuit 222 is a circuit that counts time.

[0069] The communication interface 223 is an interface for communication between the wireless communication circuit 211 and the MCU 212. Note that if the wireless communication circuit 211 and the MCU 212 are realized by a single IC, the communication interface 223 does not need to be provided.

[0070] The clock generation circuit 224 is a circuit for generating a clock in the BMU 201 .

[0071] The phase synchronization circuit 225 is a circuit that adjusts the phase of the local signal so that it matches the phase of the received signal.

[0072] The modulation circuit 226 is a circuit that modulates the signal to be transmitted to the CMU 101 .

[0073] The transmission circuit 227 is a circuit for transmitting a signal to the CMU 101. The transmission circuit 227 transmits the signal to the CMU 101 via the communication antenna ANT2.

[0074] The demodulation circuit 228 is a circuit that demodulates the signal received from the CMU 101 .

[0075] The receiving circuit 229 is a circuit for receiving a signal from the CMU 101. The receiving circuit 229 receives a signal from the CMU 101 via the communication antenna ANT2.

[0076] The communication error determination circuit 231 is a circuit that determines whether or not an abnormality has occurred in the communication between the CMU 101 and the BMU 201 .

[0077] The startup circuit 232 is a circuit for starting up the MCU 212 .

[0078] 7 , the MCU 212 includes an encryption circuit 241 and an identification circuit (ID identification circuit) 242. The MCU 212 is connected to the CAN via a CAN interface 213. A firewall is provided between the MCU 212 and the CAN. The MCU 212 also stores a table (Table of cell position and RF com. ID) 243 that indicates the correspondence between the positions of the multiple battery cells 11 in the battery pack 10 and identification information such as the wireless communication circuit of the CMU 101 of each battery pack 10.

[0079] The encryption circuit 241 is a circuit that encrypts and decrypts signals. For example, the encryption circuit 241 decrypts a signal (e.g., the voltage value of the battery cell 11) transmitted from the CMU 101 using an encryption key.

[0080] The identification circuit 242 uses the table 243 to identify the voltage value of the battery cell 11 included in the signal transmitted from the CMU 101 and the voltage value of the battery cell 11 at which position in which battery pack 10 .

[0081] With the above circuit configuration, the BMS 1 operates as follows.

[0082] First, a description will be given of the multiple states that the CMU 101 can take and the state transitions.

[0083] Fig. 8 is an explanatory diagram showing the state transition of the cell monitor circuit (CMU 101). Fig. 9 is an explanatory diagram showing whether or not power is supplied to each circuit in the states that the cell monitor circuit can be in. Fig. 10 is an explanatory diagram showing the transition of the cell monitor circuit between the sleep state and the RF active state.

[0084] As shown in Fig. 8, the CMU 101 can be in a power-off state (Power Off), a sleep state (Sleep), an RF active state, and a full power state. In each state, Fig. 9 shows whether power is supplied (ON) or not (OFF) to the voltage conversion circuit (Reg.) 141, the timer circuit (Timer (RTC)) 142, the wireless communication circuit (RF Com. Circuit) 111, and the voltage monitoring circuit (Measure Circuit) 112 of the CMU 101. A state in which power is supplied to a circuit means that the circuit is operating, and a state in which power is not supplied to a circuit means that the circuit is not operating.

[0085] The power-off state is a state in which no power is supplied to any of the voltage conversion circuit 141, the timer circuit 142, the wireless communication circuit 111, and the voltage monitoring circuit 112 (see FIG. 9). When the CMU 101 is in the power-off state and power is supplied to the voltage conversion circuit 141 and the timer circuit 142, the CMU 101 can transition to the sleep state.

[0086] The sleep state is a state in which power is supplied to the voltage conversion circuit 141 and the timer circuit 142, but not to the wireless communication circuit 111 and the voltage monitoring circuit 112 (see FIG. 9 ). The sleep state is a state in which power consumption is relatively low compared to the RF active state. In the sleep state, the CMU 101 can transition to the RF active state by supplying power to the wireless communication circuit 111 by controlling the switch 148 to be on at a timing determined by the timer circuit 142. Furthermore, in the sleep state, the CMU 101 transitions to the power-off state when power supply to the voltage conversion circuit 141 and the timer circuit 142 is cut off. The sleep state is also referred to as the second state.

[0087] The RF active state is a state in which power is supplied to the voltage conversion circuit 141, the timer circuit 142, and the wireless communication circuit 111, but not to the voltage monitoring circuit 112 (see FIG. 9 ). The RF active state is a state in which power consumption is higher than that in the sleep state. In the RF active state, the CMU 101 can receive a wake-up signal from the BMU 201; in other words, it waits for a wake-up signal. In the RF active state, the CMU 101 stops supplying power to the wireless communication circuit 111 by turning off the switch 148 at a timing determined by the timer circuit 142, thereby transitioning to the sleep state. The CMU 101 can perform intermittent operation by repeatedly transitioning to the sleep state and then back to the RF active state (see FIG. 10 ). Furthermore, when the CMU 101 receives a wake-up signal from the BMU 201 in the RF active state, it transitions to the full power state. The RF active state is also referred to as the first state.

[0088] The full power state is a state in which power is supplied to all of the voltage conversion circuit 141, timer circuit 142, wireless communication circuit 111, and voltage monitoring circuit 112 (see FIG. 9 ). In the full power state, the CMU 101 can detect the voltage values ​​of the multiple battery cells 11 and transmit them to the BMU 201. The CMU 101 can transition to a sleep state. For example, the CMU 101 can transition to the sleep state when a predetermined time has elapsed in the full power state without voltage monitoring by the voltage monitoring circuit 112 or wireless communication by the wireless communication circuit 111.

[0089] The BMU 201 transmits an activation signal to activate the CMU 101 (more specifically, an activation signal to activate the voltage monitoring circuit 112 included in the CMU 101) using the communication antenna ANT2. The timing at which the BMU 201 transmits the activation signal is, for example, the timing at which the BMU 201 attempts to acquire a voltage value detected by the CMU 101. If the CMU 101 is in an RF active state when the BMU 201 transmits the activation signal, the wireless communication circuit 111 receives the activation signal and activates the voltage monitoring circuit 112, thereby transitioning the CMU 101 to a full power state. On the other hand, if the CMU 101 is in a sleep state when the BMU 201 transmits the activation signal, the wireless communication circuit 111 cannot receive the activation signal, and the CMU 101 does not transition to a full power state.

[0090] In this way, the CMU 101 repeatedly transitions between the first state and the second state using the timing when the timer circuit 142 times out.

[0091] (Variation 1 of Embodiment 1) In this variation, a battery management system that contributes to reducing the power consumption required for processing to manage the battery pack will be described, in which the CMU 101 operates in an RF active state without using power supplied from the battery pack.

[0092] The CMU 101 in the above embodiment can operate in an RF active state using power supplied from the battery pack when the switch 148 is on. On the other hand, the CMU 101 in the above embodiment is in a sleep state when the switch 148 is off, in other words, cannot operate in an RF active state.

[0093] The CMU 101 in this modification can operate in an RF active state using power supplied from the battery 134, without using power supplied from the battery pack.

[0094] FIG. 11 is a configuration diagram showing an example of a wireless communication circuit included in a cell monitor circuit according to a modification of this embodiment.

[0095] The CMU 101 according to this modification includes an LED 113. The LED 113 emits light when the wireless communication circuit 111 satisfies a specific condition, for example.

[0096] The CMU 101 according to this modification also includes a battery 134. The battery 134 supplies power to the wireless communication circuit 111. The CMU 101 operates in an RF active state when the wireless communication circuit 111 operates using power supplied from the battery 134. The CMU 101 then activates a measurement circuit (i.e., the voltage monitoring circuit 112) when the wireless communication circuit 111, which is operating in an RF active state using power supplied from the battery 134, receives an activation signal.

[0097] In this way, the CMU 101 in this modification can operate in an RF active state using power supplied from the battery 134 without using power supplied from the battery pack.

[0098] (Second Modification of First Embodiment) In this modification, a configuration that can reduce the power consumption of the battery provided in the CMU 101 will be described for a battery management system that contributes to reducing the power consumption required for processing to manage the battery pack.

[0099] The configuration of the wireless communication circuit 111 included in the CMU 101 according to this modification is the same as that in the modification 1 (see FIG. 11 ). However, the destination of the power supplied from the battery 134 is different from that in the modification 1.

[0100] The battery 134 included in the CMU 101 according to this modification supplies power to the timer circuit 122 and the startup circuit 132. In other words, the battery 134 does not supply power to parts of the CMU 101 that are involved in the communication function (specifically, the communication interface 123, the modulation circuit 126, the transmission circuit 127, the demodulation circuit 128, the reception circuit 129, and the communication error determination circuit 131) (also referred to as communication function parts).

[0101] The timer circuit 122 is connected to the start-up circuit 132. The start-up circuit 132 is connected to the switch 148. The timer circuit 122 controls the start-up circuit 132 when a set time has elapsed (also referred to as a timeout), thereby causing the start-up circuit 132 to transmit a control signal to the switch 148 to turn the switch 148 on or off.

[0102] The communication function unit of the CMU 101 operates using power supplied from the battery pack via the switch 148 .

[0103] FIG. 12 is a configuration diagram showing an example of the voltage monitoring circuit 112 included in the CMU 101 according to this modification.

[0104] The switch 148 of this modification is a switch that switches on and off the supply of power to the wireless communication circuit 111, and is, for example, a transistor. The switch 148 is controlled by a control signal from a startup circuit 132 included in the wireless communication circuit 111. The timer circuit 122 and the startup circuit 132 control the switch 148 to be on and control the supply of power to the wireless communication circuit 111, thereby operating a communication function unit included in the wireless communication circuit 111 and transitioning the wireless communication circuit 111 to an RF active state. When the switch 148 is controlled to be off, the CMU 101 stops the supply of power to the wireless communication circuit 111 and transitions to a sleep state.

[0105] In this way, the CMU 101 supplies power from the battery 134 to the timer circuit 122 and the startup circuit 132; in other words, power is not supplied to the communication function unit, thereby reducing the power consumption of the battery 134.

[0106] Second Embodiment In this embodiment, a battery management system that contributes to reducing the power consumption required for processing to manage a battery pack will be described, in which the CMU 101 can be started without being provided with a battery.

[0107] FIG. 13 is a configuration diagram showing a first example of the BMS 2 according to this embodiment.

[0108] As shown in FIG. 13, the BMS 2 includes a CMU 101, a BMU 201, and a CMU 301, similar to the BMS 1 in the first embodiment.

[0109] The BMU 201 includes a power transmission circuit 217, a power transmission antenna 218, and a capacitor 219 in addition to the circuits included in the BMU 201 of the first embodiment.

[0110] The power transmitting circuit 217 supplies AC power output from the AC power supply 251 to the power transmitting antenna 218. The power transmitting circuit 217 has a switch 252 that switches whether or not AC power is supplied to the power transmitting antenna 218. The switch 252 can be controlled to be turned on or off by the MCU 212.

[0111] The power transmitting antenna 218 is an antenna (more specifically, a loop antenna) that transmits the AC power supplied from the power transmitting circuit 217 as an electromagnetic wave (microwave).

[0112] The capacitor 219 removes high frequency noise contained in the AC power supplied from the power transmitting circuit 217 to the power transmitting antenna 218 .

[0113] The CMU 101 includes an LED 113, a power receiving circuit 114, a power receiving antenna 115, and a capacitor 116 in addition to the circuits included in the CMU 101 of the first embodiment.

[0114] The LED 113 emits light when, for example, the wireless communication circuit 111 satisfies a specific condition.

[0115] The power receiving antenna 115 is an antenna (more specifically, a loop antenna) that receives electromagnetic waves (microwaves) transmitted from the power transmitting antenna 218 and provides AC power to the power receiving circuit 114 .

[0116] The power receiving circuit 114 converts AC power provided from the power receiving antenna 115 into DC power using a conversion circuit 151 including a rectifier circuit and a smoothing circuit, and provides the DC power to the start-up circuit 152. The start-up circuit 152 operates using the DC power provided from the conversion circuit 151 and starts up the voltage monitoring circuit 112. At this time, the start-up circuit 152 transmits a control signal that turns on a switch 148 provided in the voltage monitoring circuit 112, and by controlling the switch 148 to be on, the voltage monitoring circuit 112 is started up by power supplied from the battery pack.

[0117] The capacitor 116 removes high frequency noise contained in the AC power supplied from the power receiving antenna 115 to the power receiving circuit 114 .

[0118] With this configuration, the CMU 101 can operate without a battery by receiving power wirelessly from the BMU 201. Specifically, in the BMS 2, power is supplied from the BMU 201 to the CMU 101 using the power transmitting antenna 218 and the power receiving antenna 115, and the CMU 101 can operate using the supplied power. Furthermore, while the BMU 201 supplies power to the CMU 101 as described above, it transmits an activation signal using the communication antenna ANT2 to start the supply of power from the assembled battery to the voltage monitoring circuit 112 of the CMU 101, which then starts the supply of power from the assembled battery to the wireless communication circuit 111, allowing the CMU 101 to operate at full power.

[0119] (Variation 1 of Embodiment 2) In this variation, another example of a configuration of a battery management system that contributes to reducing the power consumption required for processing to manage a battery pack, in which the CMU 101 can be started without having a battery, will be described.

[0120] FIG. 14 is a configuration diagram showing a first example of the BMS 3 according to this modification.

[0121] As shown in FIG. 14, the BMS 3 includes a CMU 101, a BMU 201, and a CMU 301, similar to the BMS 2 in the second embodiment.

[0122] The BMU 201 includes a coil 218A instead of the power transmitting antenna 218 included in the BMU 201 of the second embodiment. The coil 218A is also referred to as a transmitting coil. The coil 218A is wound around the power line 405, and generates a magnetic flux in the power line 405 by the AC voltage supplied from the power transmitting circuit 217.

[0123] The CMU 101 includes an LED 113, a power receiving circuit 114, a coil 115A, and a capacitor 116 in addition to the circuits included in the CMU 101 of the first embodiment.

[0124] The CMU 101 includes a coil 115A instead of the power receiving antenna 115 included in the CMU 101 of the second embodiment. The coil 115A is also referred to as a receiving coil. The coil 115A is wound around the power line 405, and an AC voltage is induced in the power line 405 by a change in the magnetic flux generated in the power line 405 by the coil 218A.

[0125] The power receiving circuit 114 converts AC power based on the AC voltage generated by the coil 115A into DC power using a conversion circuit 151 and provides the DC power to the starter circuit 152. The starter circuit 152 operates using the DC power provided by the conversion circuit 151 and starts up the voltage monitoring circuit 112.

[0126] With this configuration, the CMU 101 can operate without a battery by receiving power from the BMU 201 via the power line 405. Specifically, in the BMS 3, power is supplied from the BMU 201 to the CMU 101 using the coils 218A and 115A, and the CMU 101 can operate using the supplied power. Furthermore, while the BMU 201 supplies power to the CMU 101 as described above, it transmits an activation signal using the communication antenna ANT2 to start the supply of power from the assembled battery to the voltage monitoring circuit 112 of the CMU 101, which then starts the supply of power from the assembled battery to the wireless communication circuit 111, allowing the CMU 101 to operate at full power.

[0127] (Variation 2 of Embodiment 2) In this variation, another example of a configuration of a battery management system that contributes to reducing the power consumption required for processing to manage a battery pack, in which the CMU 101 can be started without having a battery, will be described.

[0128] FIG. 15 is a configuration diagram showing a first example of the BMS 4 according to this modification.

[0129] As shown in FIG. 15, the BMS 4 includes a CMU 101, a BMU 201, and a CMU 301, similar to the BMS 2 in the second embodiment.

[0130] BMU 201 includes a transformer 218B instead of power transmission antenna 218 included in BMU 201 of the second embodiment. Transformer 218B is connected to power line 405 via capacitors 218C and 218D. Capacitors 218C and 218D prevent DC power from flowing from transformer 218B to power line 405.

[0131] In this way, the BMU 201 applies an AC voltage to the power line 405 via the transformer 218B.

[0132] The CMU 101 includes a transformer 115B instead of the power receiving antenna 115 included in the CMU 101 of the second embodiment. The transformer 115B is connected to the power line 405 via capacitors 115C and 115D. The capacitors 115C and 115D suppress the flow of DC power from the transformer 115B to the power line 405. When an AC voltage is applied to the power line 405 by the transformer 218B, the AC voltage generated on the power line 405 is applied to the power receiving circuit 114 via the transformer 115B. The power receiving circuit 114 converts AC power based on the AC voltage applied via the transformer 115B into DC power using a conversion circuit 151 and provides the DC power to the start-up circuit 152. The start-up circuit 152 operates using the DC power provided by the conversion circuit 151 and starts up the voltage monitoring circuit 112.

[0133] The frequency of the AC current flowing through the power line 405 (in other words, the frequency of the AC power output by the AC power supply 251) will be described.

[0134] 16 is an explanatory diagram showing the impedance of the power line 405 in the BMS 4 according to this modification. In Fig. 16, the horizontal axis represents frequency on a logarithmic scale, and the vertical axis represents the impedance of the power line 405 on a logarithmic scale.

[0135] 16, in the frequency range of greater than 0 kHz to approximately 10 kHz, the impedance of the power line 405 is relatively small, for example, a few ohms or less. For example, the rotation speed of the motor 400 is within the above range, for example, 2000 rpm (i.e., approximately 33 Hz) or 50,000 rpm (i.e., approximately 833 Hz).

[0136] In addition, in the frequency range of about 10 kHz to about 10 MHz, the impedance of the power line 405 has a substantially constant value (for example, about several ohms).

[0137] Furthermore, at frequencies of about 100 MHz or higher, the higher the frequency, the higher the impedance of the power line 405. For example, the impedance of the power line 405 is about several ohms at about 100 MHz and exceeds 10 ohms at about 1 GHz.

[0138] The resonant frequency of the portion of BMU 201 involved in the function of transmitting power (e.g., coil 218A and capacitor 219) (also referred to as a power transmitting function unit) can be set to the same frequency as the resonant frequency of the portion of CMU 101 involved in the function of receiving power (e.g., coil 115A and capacitor 116) (also referred to as a power receiving function unit). In this way, the power transmitting function unit of BMU 201 can transmit maximum power in a resonant state, and the power receiving function unit of CMU 101 can receive maximum power in a resonant state, so that power can be transmitted from BMU 201 to CMU 101 with higher efficiency.

[0139] Furthermore, in power transmission using the power line 405, the frequency of the AC current flowing through the power line 405 can be set to, for example, a frequency higher than the operating frequency of the load connected to the battery pack, i.e., the motor 400. In this case, the resonant frequency of the power transmitting function unit of the BMU 201 can be set to a frequency higher than the operating frequency of the load. Also, the resonant frequency of the power receiving function unit of the CMU 101 can be set to a frequency higher than the operating frequency of the load. In this way, AC power can be transmitted using the power line 405 while suppressing the current flowing through the power line 405.

[0140] Furthermore, in power transmission using the power line 405, the frequency of the AC current flowing through the power line 405 can be set to, for example, a frequency higher than 10 MHz. In this case, the resonant frequency of the power transmitting function unit of the BMU 201 can be set to a frequency higher than 10 MHz. Also, the resonant frequency of the power receiving function unit of the CMU 101 can be set to a frequency higher than 10 MHz. In this way, AC power can be transmitted using the power line 405 while suppressing the current flowing through the power line 405.

[0141] With this configuration, the CMU 101 can operate without a battery by receiving power from the BMU 201 via the power line 405. Specifically, in the BMS 4, power is supplied from the BMU 201 to the CMU 101 using transformers 218B and 115B, and the CMU 101 can operate using the supplied power. Furthermore, while the BMU 201 supplies power to the CMU 101 as described above, it transmits an activation signal using the communication antenna ANT2 to start the supply of power from the assembled battery to the voltage monitoring circuit 112 of the CMU 101, which then starts the supply of power from the assembled battery to the wireless communication circuit 111, allowing the CMU 101 to operate at full power.

[0142] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0143] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0144] (1) A battery management system for managing a battery pack, comprising: a management circuit for managing the battery pack; and a plurality of monitoring circuits for monitoring the battery pack, one of the plurality of monitoring circuits having a wireless communication circuit and a timer circuit, and repeatedly transitioning between a first state in which the wireless communication circuit is powered and can receive an activation signal transmitted by the management circuit, and a second state in which the wireless communication circuit is not powered, using the timing when the timer circuit times out.

[0145] According to the above aspect, the monitoring circuit performs intermittent operation by repeatedly transitioning between the first state and the second state, and in the second state, no power is supplied to the wireless communication circuit, thereby reducing the power consumption required for processing to manage the battery pack. Thus, the battery management system contributes to reducing the power consumption required for processing to manage the battery pack.

[0146] (2) The battery management system described in (1), wherein the plurality of monitoring circuits include a battery that supplies power to the wireless communication circuit and a measurement circuit for monitoring the voltage of the battery pack or measuring the current of the battery pack, and activates the measurement circuit when the wireless communication circuit, operating in the first state by power supply from the battery, receives an activation signal transmitted by the management circuit.

[0147] According to the above aspect, when power is supplied to the wireless communication circuit, the monitoring circuit receives an activation signal to activate the measurement circuit to monitor the voltage of the battery pack or measure the current of the battery pack, thereby enabling the battery management system to perform processing for managing the battery pack while reducing power consumption.

[0148] (3) A battery management system as described in (1), wherein a communication function unit of the wireless communication circuit operates using power supplied from the battery pack, the one monitoring circuit further has a battery that supplies power to the timer circuit, and the one monitoring circuit transitions to the first state when power is supplied from the battery pack to the wireless communication circuit using the timing when the timer circuit times out, and transitions to the second state when the power supply is stopped.

[0149] According to the above aspect, in the battery management system, the power source for the wireless communication circuit of the monitoring circuit is the battery pack, not a battery, so that battery power consumption is reduced. Therefore, the battery management system contributes to further reducing the power consumption required for processing to manage the battery pack.

[0150] (4) A battery management system described in any one of (1) to (3), wherein the management circuit further includes a power transmitting antenna that transmits AC power as electromagnetic waves, and the one monitoring circuit further includes a power receiving antenna that receives the AC power transmitted as electromagnetic waves by the power transmitting antenna.

[0151] According to the above aspect, the monitoring circuit can receive power wirelessly from the management circuit, eliminating the need for a battery. Therefore, the battery management system contributes to reducing the power consumption required for processing to manage the battery pack without requiring a battery.

[0152] (5) The battery management system described in (4), wherein the one monitoring circuit includes a conversion circuit that converts AC power received by the power receiving antenna into DC power, and the DC power converted by the conversion circuit activates a measurement circuit that performs measurements for managing the battery pack.

[0153] According to the above aspect, the monitoring circuit can operate using DC power converted from AC power wirelessly transmitted from the management circuit, which makes it easier to operate without using a battery. Therefore, the battery management system does not require a battery and contributes to reducing the power consumption required for processing to manage the battery pack.

[0154] (6) The battery management system described in (1), wherein the management circuit further includes a transmitting coil that generates magnetic flux in the power line of the assembled battery, and one of the plurality of monitoring circuits further includes a receiving coil in which an AC voltage is induced by a change in the magnetic flux generated in the power line by the transmitting coil.

[0155] According to the above aspect, the monitoring circuit can receive AC power transmitted from the management circuit via the power line, eliminating the need for a battery. Therefore, the battery management system contributes to reducing the power consumption required for processing to manage the battery pack without requiring a battery.

[0156] (7) The battery management system described in (6), wherein the one monitoring circuit includes a conversion circuit that converts AC power based on the AC voltage generated by the receiving coil into DC power, and the DC power converted by the conversion circuit activates a measurement circuit that performs measurements for managing the assembled battery.

[0157] According to the above aspect, the monitoring circuit can operate using DC power converted from AC power transmitted from the management circuit via the power line, which makes it easier to operate without using a battery. Therefore, the battery management system does not require a battery and contributes to reducing the power consumption required for processing to manage the battery pack.

[0158] (8) The battery management system according to (7), wherein the resonant frequency of the power transmitting function unit included in the management circuit is the same as the resonant frequency of the power receiving function unit included in the one monitoring circuit.

[0159] According to the above aspect, since the resonant frequencies of the power transmitting unit and the power receiving unit are the same, the power transmitting unit can transmit maximum power in a resonant state, and the power receiving unit can receive maximum power in a resonant state. This allows power to be transmitted from the management circuit to the monitoring circuit with higher efficiency. In other words, the output power of the management circuit for transmitting sufficient power for the operation of the monitoring circuit to the monitoring circuit can be reduced. Therefore, the battery management system contributes to further reducing the power consumption required for processing to manage the battery pack without including a battery.

[0160] (9) A battery management system as described in (7), wherein the resonant frequency of the power transmission function unit provided in the management circuit is higher than the operating frequency of the load connected to the assembled battery, and the resonant frequency of the power receiving function unit provided in one of the monitoring circuits is higher than the operating frequency of the load connected to the assembled battery.

[0161] According to the above aspect, the battery management system transmits AC power through the power lines at a frequency higher than the operating frequency of the load connected to the battery pack. Generally, the impedance characteristic of the power line is such that the higher the frequency, the higher the impedance. Therefore, by transmitting AC power through the power lines at a frequency higher than the operating frequency of the load connected to the battery pack, it is possible to transmit AC power using the power lines while suppressing the current flowing through the power lines. Therefore, the battery management system contributes to further reducing the power consumption required for processing to manage the battery pack without including a battery.

[0162] (10) A battery management system as described in (7), wherein the resonant frequency of the power transmitting function unit provided in the management circuit is higher than 10 MHz, and the resonant frequency of the power receiving function unit provided in one of the monitoring circuits is higher than 10 MHz.

[0163] According to the above aspect, the battery management system transmits AC power over the power lines at a frequency higher than 10 MHz. Generally, the impedance characteristic of a power line is such that the higher the frequency, the higher the impedance. Therefore, by transmitting AC power over the power lines at a frequency higher than 10 MHz, it is possible to transmit AC power using the power lines while suppressing the current flowing through the power lines. Therefore, the battery management system contributes to further reducing the power consumption required for processing to manage the battery pack without including a battery.

[0164] (11) A battery management system according to any one of (1) to (10), wherein the plurality of monitoring circuits include a cell monitoring circuit that monitors one or more battery cells that constitute the battery pack, or a current monitoring circuit that measures the current flowing through the battery pack.

[0165] According to the above aspect, the battery management system contributes to reducing the power consumption required for processing to manage the assembled battery using the cell monitoring circuit or the current monitoring circuit.

[0166] The present disclosure can be applied to a battery management system in which wireless communication is performed within the system.

[0167] 1, 2, 3, 4 BMS 10 Battery pack 11 Battery cell 20 Junction box 100 Monitoring circuit 101 CMU (Cell Monitoring Unit) 111, 211 Wireless communication circuit 112 Voltage monitoring circuit 113 LED 114 Power receiving circuit 115 Power receiving antenna 115A, 218A Coil 115B, 218B, 501, 502 Transformer 115C, 115D, 116, 218C, 218D, 219 Capacitor 121, 141, 221 Voltage conversion circuit 122, 142, 222 Timer circuit 123, 145, 223, 323 Communication interface 124, 224 Clock generation circuit 125, 146, 225 Phase synchronization circuit 126, 226 Modulation circuit 127, 227 Transmission circuit 128, 228 Demodulation circuit 129, 229 Reception circuit 131, 231 Communication error determination circuit 132, 152, 232 Startup circuit 134 Battery 143 Multiplexer 144, 322 AD converter 147, 241 Encryption circuit 148, 252 Switch 151 Conversion circuit 200 Management circuit 201 BMU 212 MCU 213 CAN interface 215, 312 Power supply circuit 216, 313 Insulated communication circuit 217 Power transmission circuit 218 Power transmission antenna 242 Identification circuit 243 Table 251 AC power supply 301 CMU (Current Monitoring Unit) 311 Current measuring circuit 321 Amplification circuit 400 Motor 401 Relay 402 Shunt resistor 405 Power line ANT1, ANT2 Communication antenna

Claims

1. A battery management system for managing a battery pack, A management circuit for managing the battery pack; A plurality of monitoring circuits for monitoring the battery pack, One of the plurality of monitoring circuits is A wireless communication circuit; A timer circuit, a first state in which the wireless communication circuit is capable of receiving a wake-up signal transmitted by the management circuit due to power being supplied to the wireless communication circuit, and a second state in which the wireless communication circuit is not supplied with power are repeatedly transitioned to the first state at a timing when the timer circuit times out; The management circuit further comprises: a transmission coil that generates a magnetic flux in a power line of the battery pack, One of the plurality of monitoring circuits further comprises: A receiving coil in which an AC voltage is induced by a change in magnetic flux generated in the power line by the transmitting coil is provided. Battery management system.

2. The plurality of monitoring circuits include a battery for supplying power to the wireless communication circuit; a measurement circuit for monitoring the voltage of the battery pack or measuring the current of the battery pack; When the wireless communication circuit, which is operating in the first state by the power supply from the battery, receives a wake-up signal transmitted by the management circuit, the measurement circuit is activated. The battery management system according to claim 1 .

3. a communication function unit of the wireless communication circuit operates using power supplied from the battery pack; The one monitoring circuit further includes: a battery for powering the timer circuit; The one monitoring circuit is Using a timing when the timer circuit times out, power is supplied from the battery pack to the wireless communication circuit, thereby causing a transition to the first state, and the supply of power is stopped, thereby causing a transition to the second state. The battery management system according to claim 1 .

4. The management circuit further comprises: A power transmitting antenna is provided for transmitting AC power as electromagnetic waves, The one monitoring circuit further includes: The power transmitting antenna includes a power receiving antenna for receiving the AC power transmitted as an electromagnetic wave. The battery management system according to any one of claims 1 to 3.

5. The one monitoring circuit is a conversion circuit for converting the AC power received by the power receiving antenna into DC power; A measurement circuit is started by the DC power converted by the conversion circuit, the measurement circuit being used for measurement for managing the battery pack. The battery management system according to claim 4.

6. The one monitoring circuit is a conversion circuit for converting AC power based on the AC voltage generated by the receiving coil into DC power; A measurement circuit is started by the DC power converted by the conversion circuit, the measurement circuit being used for measurement for managing the battery pack. The battery management system according to claim 1 .

7. The resonant frequency of the power transmitting function unit included in the management circuit is the same as the resonant frequency of the power receiving function unit included in the one monitoring circuit. The battery management system according to claim 6.

8. a resonant frequency of the power transmitting function unit included in the management circuit is higher than an operating frequency of a load connected to the battery pack; The resonant frequency of the power receiving function unit included in the one monitoring circuit is higher than the operating frequency of the load connected to the battery pack. The battery management system according to claim 6.

9. The resonant frequency of the power transmission function unit of the management circuit is higher than 10 MHz, The resonant frequency of the power receiving function unit of the one monitoring circuit is higher than 10 MHz. The battery management system according to claim 6.

10. the plurality of monitoring circuits include a cell monitoring circuit that monitors one or more battery cells that constitute the battery pack, or a current monitoring circuit that measures a current flowing through the battery pack; The battery management system according to any one of claims 1 to 3.