Battery management system

Abstract

A BMS (1) for managing an assembled battery comprises: a BMU (201) that manages an assembled battery, and includes a communication antenna (ANT2); and one or more CMUs (101) that monitors the assembled battery, each of the one or more CMUs (101) including a communication antenna (ANT1) communicating with the communication antenna (ANT2), wherein a communication antenna group including the communication antenna (ANT2) and one or more communication antennas (ANT1) is arranged in a straight line, the BMS (1) further comprises a conductor (42) that covers at least a portion of the communication antenna group, and the conductor (42) has a concave portion (44) that extends in the direction in which the communication antenna group is arranged, and is recessed in the direction away from the communication antenna group in a cross section perpendicular to the arrangement direction.

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 including a battery pack having a plurality of battery cells (see, for example, Patent Document 1). The battery management system manages the battery pack by transmitting and receiving information via wireless communication between components included in the system.

[0003] US Patent Application Publication No. 2021 / 0305681

[0004] In a battery management system including a battery pack, there is a problem that normal wireless communication may be hindered due to the relatively narrow space through which electromagnetic waves (also called radio waves) propagate or due to interference from radio waves (also called incoming waves) arriving from outside.

[0005] The present disclosure provides a battery management system and the like that can suppress deterioration of the quality of wireless communication.

[0006] The battery management system of the present disclosure is a battery management system for managing a battery pack, comprising: a management circuit for managing the battery pack, the management circuit having a first communication antenna; and one or more monitoring circuits for monitoring the battery pack, each of the one or more monitoring circuits having a second communication antenna that communicates with the first communication antenna; a communication antenna group including the first communication antenna and one or more second communication antennas arranged in a straight line; and the battery management system further comprises a conductor covering at least a portion of the communication antenna group, the conductor extending in the arrangement direction of the communication antenna group and having a recess that is recessed in a direction away from the communication antenna group in a cross section perpendicular to the arrangement direction.

[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, it is possible to suppress deterioration of the quality of wireless communication.

[0009] 1. A first external view showing an example of a battery management system according to an embodiment. A second external view showing an example of a battery management system according to an embodiment. A configuration diagram showing an example of a battery management system according to an embodiment. A configuration diagram showing an example of a wireless communication circuit provided in a cell monitoring circuit according to an embodiment. A configuration diagram showing an example of a voltage monitoring circuit provided in a cell monitoring circuit according to an embodiment. A configuration diagram showing an example of a current measuring circuit provided in a current monitoring circuit according to an embodiment. A configuration diagram showing an example of a wireless communication circuit provided in a management circuit according to an embodiment. A configuration diagram showing an example of an MCU provided in a management circuit according to an embodiment. A cross-sectional view showing an example of a cross section of a battery management system taken along the IX-IX cross-sectional line of FIG. 1. An explanatory diagram of a recess in the cross-sectional view of FIG. 9. A third external view showing an example of a battery management system according to an 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] In a battery management system, it is assumed that the management circuit and the monitoring circuit manage the battery pack by sending and receiving information via wireless communication. By using wireless communication, the battery management system has the advantage of not requiring the cables required for wired communication.

[0013] However, radio waves transmitted by the battery management system may be subject to interference from external signals. Furthermore, when the battery management system is installed in a vehicle, the space through which radio waves can propagate is limited, resulting in relatively large attenuation of the radio waves. These factors can cause degradation in the quality of the radio communications transmitted by the battery management system, potentially hindering normal wireless communications.

[0014] The present disclosure provides a battery management system and the like that can suppress deterioration of the quality of wireless communication.

[0015] 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.

[0016] Hereinafter, the embodiments will be specifically described with reference to the drawings.

[0017] 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.

[0018] (Embodiment) In this embodiment, a battery management system that suppresses degradation of the quality of wireless communication will be described.

[0019] 1 and 2 are external views showing an example of a battery management system 1 (hereinafter also referred to as a BMS (Battery Management System) 1) according to this embodiment.

[0020] 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.

[0021] For example, there may be one or more monitoring circuits 100, each of which is disposed on one 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.

[0022] 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.

[0023] The BMS 1 also includes a cover 40 that is placed on one or more battery cells. Fig. 1 shows the BMS 1 with the cover 40 in place, and Fig. 2 shows the BMS 1 with the cover 40 removed. The BMS 1 is in use with the cover 40 in place.

[0024] The cover 40 includes conductors (for example, conductors 42 and 42A in FIG. 1) in a portion thereof. The characteristics of the conductors included in the cover 40 will be described in detail later.

[0025] FIG. 3 is a configuration diagram showing an example of the BMS 1 according to this embodiment.

[0026] Fig. 4 is a configuration diagram showing an example of the wireless communication circuit 111 included in the first cell monitoring circuit (CMU 101). Fig. 4 also shows the peripheral parts of the wireless communication circuit 111 in the configuration diagram of Fig. 3.

[0027] 5 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. 5 also shows the peripheral parts of the voltage monitoring circuit 112 in the configuration diagram of Fig. 3.

[0028] 6 is a configuration diagram showing an example of the current measurement circuit 311 provided in the current monitoring circuit (CMU 301). Note that Fig. 6 also shows the peripheral parts of the current measurement circuit 311 in the configuration diagram of Fig. 3.

[0029] 7 is a block diagram showing an example of the wireless communication circuit 211 included in the management circuit (BMU 201). Note that Fig. 7 also shows the peripheral parts of the wireless communication circuit 211 in the block diagram of Fig. 3.

[0030] 8 is a block diagram showing an example of the MCU 212 included in the management circuit (BMU 201). Note that Fig. 8 also shows the peripheral parts of the MCU 212 in the block diagram of Fig. 3.

[0031] 3 focuses on one battery pack 10 out of the plurality of 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. 3. 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, a relay 401 inserted in the power line 405, and a shunt resistor 402.

[0032] 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.

[0033] The shunt resistor 402 is a resistor for measuring the current flowing through the power line 405 .

[0034] 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.

[0035] 3, the CMU 101 includes a wireless communication circuit 111 and a communication antenna ANT1 for communicating with the BMU 201. The communication antenna ANT1 is capable of communicating with a communication antenna ANT2 included in the BMU 201. The communication antenna ANT1 corresponds to a second communication antenna. When there are multiple CMUs 101, the communication antennas ANT1 of the multiple CMUs 101 are arranged in a straight line.

[0036] In addition, when there are multiple CMUs 101, the communication antennas ANT1 of all of the CMUs 101 do not need to be arranged in a single line, but it is sufficient that the communication antennas ANT1 of some of the multiple CMUs 101 are arranged in a single line. In this case, the communication antennas ANT1 of the CMUs 101 other than the above-mentioned some of the CMUs 101 may be arranged in another single line. Figure 2 shows a state in which multiple communication antennas ANT1 are arranged in two straight lines.

[0037] The CMU 101 also includes a voltage monitoring circuit 112 that monitors the voltage of each 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.

[0038] As shown in FIG. 4 , 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] The clock generation circuit 124 is a circuit for generating a clock in the CMU 101 .

[0043] 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.

[0044] The modulation circuit 126 is a circuit that modulates the signal to be transmitted to the BMU 201 .

[0045] 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.

[0046] The demodulation circuit 128 is a circuit that demodulates the signal received from the BMU 201 .

[0047] 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.

[0048] 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 .

[0049] 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.

[0050] As shown in FIG. 5 , 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] The AD converter 144 converts the voltage value (analog value) of the battery cell 11 selected by the multiplexer 143 into a digital value.

[0055] 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 realized by a single IC, the communication interface 145 does not need to be provided.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 .

[0060] 3, 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The AD converter 322 converts the value (analog value) of the voltage generated across the shunt resistor 402 into a digital value.

[0066] The communication interface 323 is an interface for communication between the CMU 301 and the BMU 201 .

[0067] 3, the BMU 201 includes a wireless communication circuit 211 and a communication antenna ANT2 for communicating with the CMU 101. The communication antenna ANT2 corresponds to a first communication antenna. The communication antenna ANT2 is arranged in a straight line together with the communication antenna ANT1 of the CMU 101, which is also arranged in a straight line. The communication antennas ANT1 and ANT2 are also referred to as a communication antenna group.

[0068] The BMU 201 also includes an MCU (Micro Controller Unit) 212 for managing the battery pack and a CAN (Controller Area Network) interface 213. 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 7, 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, in FIG. 7, "ID0A" is shown as identification information of the wireless communication circuit 211. The identification information of the communication interface 223 may be stored in any memory included in the wireless communication circuit 211.

[0074] 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.

[0075] The timer circuit 222 is a circuit that counts time.

[0076] 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.

[0077] The clock generation circuit 224 is a circuit for generating a clock in the BMU 201 .

[0078] 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.

[0079] The modulation circuit 226 is a circuit that modulates the signal to be transmitted to the CMU 101 .

[0080] 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.

[0081] The demodulation circuit 228 is a circuit that demodulates the signal received from the CMU 101 .

[0082] 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.

[0083] 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 .

[0084] The startup circuit 232 is a circuit for starting up the MCU 212 .

[0085] 8 , 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.

[0086] 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.

[0087] 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 .

[0088] Next, the conductor that is part of the cover 40 will be described.

[0089] As shown in Fig. 1, the cover 40 has conductors 42 and 42A as examples of conductors. In Fig. 1, the communication antennas are arranged in two rows at different positions in the X-axis direction. Of the two rows of communication antennas, conductor 42 is arranged in a position covering one row of communication antennas on the negative side of the X-axis, and conductor 42A is arranged in a position covering one row of communication antennas on the positive side of the X-axis.

[0090] The following describes the conductor 42. Note that the description of the conductor 42A is omitted because it is similar to the conductor 42.

[0091] FIG. 9 is a cross-sectional view showing an example of a cross section of the BMS 1 taken along the line IX-IX in FIG.

[0092] The cross section of the BMS 1 shown in FIG. 9 is a cross section obtained by virtually cutting the BMS 1 along a plane parallel to the XZ plane, that is, a plane perpendicular to the arrangement direction of the communication antenna group (that is, the Y-axis direction).

[0093] The cross section shown in FIG. 9 includes the battery cell 11, the CMU 101, the communication antenna ANT1, and the cover 40.

[0094] The cover 40 is a cover member that covers the battery pack, the BMU 201, and the CMU 101 from above (i.e., the positive Z-axis direction side). For example, when the battery pack is used as a battery for an automobile, the cover 40 may be part of the body structure of the automobile.

[0095] The cover 40 has a conductor 42 in a part thereof. The material of the conductor 42 is, for example, iron or aluminum, but is not limited to these.

[0096] The conductor 42 is disposed in a position that covers at least a portion of the communication antenna group (i.e., communication antennas ANT1 and ANT2) (see FIG. 1). Note that the conductor 42 may be disposed in a position that covers the entire communication antenna group.

[0097] The conductor 42 has a recess 44. The recess 44 extends in the direction in which the communication antenna group is arranged (i.e., in the Y-axis direction) (see FIG. 1). The recess 44 is recessed in a direction away from the antenna group (i.e., in the positive Z-axis direction) in the cross section shown in FIG. 9. In other words, the recess 44 is a recessed portion formed by the conductor 42 being recessed in the positive Z-axis direction.

[0098] Fig. 10 is an explanatory diagram of the recess 44 in the cross-sectional view of Fig. 9. The description of the recess 44 will continue with reference to Fig. 10.

[0099] The recess 44 corresponds to a space P surrounded by a surface S1, which is an imaginary extension of the surface S of the cover 40, and the conductor 42. The cross-sectional shape of the recess 44 shown in Fig. 10 is rectangular. The recess 44 has the cross-sectional shape shown in Fig. 10 as a cross-sectional shape parallel to the XZ plane, and has a rectangular parallelepiped shape extending in the Y-axis direction.

[0100] The recess 44 functions as a waveguide through which radio waves transmitted for wireless communication by the communication antennas included in the communication antenna group (i.e., communication antennas ANT1 and ANT2) propagate. In this case, the conductor 42 has the same function as a general rectangular waveguide, specifically, it has the function of suppressing interference between radio waves propagating through the recess 44, which functions as a waveguide, and incoming waves arriving from outside, and of allowing radio waves to stably exist and propagate within the recess 44. This allows radio waves transmitted by the communication antennas to propagate smoothly within the recess 44, suppressing deterioration in the quality of wireless communication by the communication antennas, in other words, contributing to maintaining quality without degradation.

[0101] The recess 44 may be characterized in that one of the width in the Z-axis direction (corresponding to the first direction) and the width in the Y-axis direction (corresponding to the second direction) of the recess 44 is longer than the wavelength of radio waves used in wireless communication by the communication antenna group, and the other is shorter than the wavelength. For example, the wavelength is about 12 cm when the frequency of the radio waves used in wireless communication is 2.4 GHz.

[0102] As a specific example, the recess 44 may have a width w1 in the X-axis direction longer than the wavelength and a width w2 in the Z-axis direction shorter than the wavelength. Alternatively, as another specific example, the recess 44 may have a width w2 in the Z-axis direction longer than the wavelength and a width w1 in the Y-axis direction shorter than the wavelength.

[0103] This allows the propagation mode of radio waves existing and propagating within the recess 44 to be TE mode or TM mode. This allows the recess 44 to more stably allow radio waves to exist and propagate within the recess 44, and further suppresses deterioration in the quality of wireless communication by the communication antenna.

[0104] As another specific example, the width w1 of the recess 44 in the X-axis direction may be an integer multiple of the wavelength, and the width w2 of the recess 44 in the Z-axis direction may be approximately half the wavelength. In this way, the recess 44 can more stably allow radio waves to exist and propagate within the recess 44, and deterioration of the quality of wireless communication by the communication antenna can be further suppressed.

[0105] The material of the cover 40 except for the conductor 42 may be conductive or non-conductive. If the material of the above-mentioned portion is conductive, the conductor 42, together with the cover 40, suppresses deterioration of the quality of wireless communication by the communication antenna, in other words, contributes to maintaining the quality without deterioration.

[0106] Another embodiment of the cover 40 will now be described.

[0107] 11 is a third external view showing an example of the battery management system 1 according to the present embodiment. In FIG. 11, a cover 40 is configured as a part of a housing 41 that houses the battery pack.

[0108] The housing 41 may be a housing for housing the battery when the battery pack is used as a car battery, or may be a housing for housing the battery when the battery pack is used as a general battery (or a charge / discharge device).

[0109] The housing 41 may be a housing that hermetically houses the battery pack. Hermetically housing the battery pack has the effect of preventing water or dust from entering the recess 44 that functions as a waveguide.

[0110] 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.

[0111] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0112] (1) A battery management system for managing a battery pack, comprising: a management circuit for managing the battery pack, the management circuit having a first communication antenna; and one or more monitoring circuits for monitoring the battery pack, each of the one or more monitoring circuits having a second communication antenna that communicates with the first communication antenna; a communication antenna group including the first communication antenna and one or more second communication antennas arranged in a straight line; and the battery management system further comprising a conductor covering at least a portion of the communication antenna group, the conductor extending in the arrangement direction of the communication antenna group and having a recess that is recessed in a direction away from the communication antenna group in a cross section perpendicular to the arrangement direction.

[0113] According to the above aspect, the recess functions as a waveguide for radio waves used in wireless communication by the communication antenna group. The recess has the function of suppressing interference between radio waves propagating within the recess and incoming waves from outside, and of stably maintaining the radio waves within the recess. This allows radio waves transmitted from the communication antennas to propagate smoothly within the recess, suppressing deterioration in the quality of wireless communication between the communication antennas, or in other words, contributing to maintaining quality without degradation. Therefore, the battery management system can suppress deterioration in the quality of wireless communication.

[0114] (2) A battery management system as described in (1), wherein one of the width of the recess in a first direction away from the communication antenna group and the width in a second direction perpendicular to the first direction in the cross section is longer than the wavelength of the radio waves used for wireless communication by the communication antenna group, and the other is shorter than the wavelength.

[0115] According to the above aspect, the recess can set the propagation mode of radio waves present within the recess to TE mode or TM mode. This allows radio waves to propagate more stably within the recess, thereby stabilizing wireless communication via the communication antenna. Therefore, the battery management system can further suppress deterioration of the quality of wireless communication.

[0116] (3) The battery management system according to (1) or (2), wherein the cross-sectional shape of the recess is rectangular.

[0117] According to the above aspect, radio waves can be more stably present in the recess, which contributes to suppressing deterioration of the quality of wireless communication. Furthermore, there is an advantage that the design of the conductor is easier. Therefore, the battery management system can suppress deterioration of the quality of wireless communication.

[0118] (4) A battery management system according to any one of (1) to (3), wherein the conductor is part of a cover member that covers the assembled battery, the management circuit, and the one or more monitoring circuits.

[0119] According to the above aspect, the battery management system can more easily suppress deterioration of the quality of wireless communication by using a cover member that covers the assembled battery, the management circuit, and one or more monitoring circuits.

[0120] (5) A battery management system according to any one of (1) to (3), wherein the conductor is part of a housing that houses the battery pack.

[0121] According to the above aspect, the battery management system can more easily suppress deterioration of the quality of wireless communication by using the conductor that is part of the housing that houses the battery pack.

[0122] (6) A battery management system according to any one of (1) to (3), wherein the conductor is part of the body structure of a vehicle in which the battery pack is mounted.

[0123] According to the above aspect, the battery management system can more easily suppress deterioration of the quality of wireless communication by using a conductor that is part of the body structure of the automobile in which the assembled battery is mounted.

[0124] (7) A battery management system according to any one of (1) to (3), wherein the conductor is part of a housing that hermetically houses the battery pack.

[0125] According to the above aspect, the battery management system uses the conductor that is part of the housing that hermetically houses the battery pack to prevent water or dust from entering the recess that functions as a waveguide for wireless communication, thereby preventing deterioration of communication quality due to the intrusion of water or dust. Thus, the battery management system can more easily prevent deterioration of wireless communication quality.

[0126] The present disclosure can be applied to a battery management system in which wireless communication is performed within the system.

[0127] REFERENCE SIGNS LIST 1 BMS 10 Battery pack 11 Battery cell 20 Junction box 40 Cover 41 Housing 42, 42A Conductor 44 Recess 100 Monitoring circuit 101 CMU (Cell Monitoring Unit) 111, 211 Wireless communication circuit 112 Voltage monitoring circuit 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, 232 Startup circuit 143 Multiplexer 144, 322 AD converter 147, 241 Encryption circuit 148 Switch 200 Management circuit 201 BMU 212 MCU 213 CAN interface 215, 312 Power supply circuit 216, 313 Insulated communication circuit 242 Identification circuit 243 Table 301 CMU (Current Monitoring Unit) 311 Current measurement circuit 321 Amplification circuit 400 Motor 401 Relay 402 Shunt resistor 405 Power line 501, 502 Transformer ANT1, ANT2 Communication antenna P Space S Surface S1 Surface

Claims

1. A battery management system for managing a battery pack, a management circuit for managing the battery pack, the management circuit including a first communication antenna; one or more monitoring circuits for monitoring the battery pack, each of the one or more monitoring circuits including a second communication antenna that communicates with the first communication antenna; a communication antenna group including the first communication antenna and one or more of the second communication antennas is arranged in a straight line; The battery management system further includes a conductor covering at least a portion of the communication antenna group. The conductor extends in the arrangement direction of the communication antenna group and has a recess that is recessed in a direction away from the communication antenna group in a cross section perpendicular to the arrangement direction. Battery management system.

2. One of a width of the recess in a first direction away from the communication antenna group and a width of the recess in a second direction perpendicular to the first direction in the cross section is longer than a wavelength of radio waves used in wireless communication by the communication antenna group, and the other is shorter than the wavelength. The battery management system according to claim 1 .

3. The cross-sectional shape of the recess is rectangular. The battery management system according to claim 1 or 2.

4. The conductor is a part of a cover member that covers the battery pack, the management circuit, and the one or more monitoring circuits. The battery management system according to claim 1 or 2.

5. The conductor is a part of a housing that houses the battery pack. The battery management system according to claim 1 or 2.

6. The conductor is a part of the body structure of the automobile in which the battery pack is mounted. The battery management system according to claim 1 or 2.

7. The conductor is a part of a housing that hermetically houses the battery pack. The battery management system according to claim 1 or 2.