Wireless device and power supply unit

Abstract

A wireless device (30, 40) of a battery monitoring system (100) comprises a wireless antenna (33, 43), and a proximity conductor (37, 47) overlapping at least a part of a projection surface of the wireless antenna when a predetermined direction is defined as a projection direction.

Description

Wireless device and power supply unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-155801 filed on September 21, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a wireless device and a power supply unit of a battery monitoring system.

[0003] Recently, there have been battery monitoring systems that transmit or receive battery status information of battery cells via wireless communication. Such a battery monitoring system is described in, for example, Patent Document 1.

[0004] US Patent Application Publication No. 2017 / 0301961

[0005] It is desirable to design such wireless devices so that the antenna characteristics can be maintained at appropriate values ​​under any environment.

[0006] The present disclosure has been made in consideration of the above circumstances, and its main object is to provide a wireless device and a power supply unit that can maintain antenna characteristics at appropriate values.

[0007] The means for solving the above problem is a wireless device of a battery monitoring system, which comprises a wireless antenna and a nearby conductor that overlaps with at least a portion of the projection surface of the wireless antenna when a predetermined direction is the projection direction.

[0008] This nearby conductor creates electrostatic coupling with the radio antenna, generating capacitance. If this capacitance is large, even if stray capacitance occurs between the radio antenna and another conductor, the proportion of the capacitance between the radio antenna and the conductor increases, and the proportion of the stray capacitance between the radio antenna and the other conductor, i.e., the amount of fluctuation, can be made relatively small compared to the original capacitance. As a result, even if the surrounding environment changes, the impact on the antenna characteristics can be suppressed.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a schematic diagram of a vehicle, Fig. 2 is a block diagram showing the configuration of a battery pack, Fig. 3 is a diagram showing the interior of the battery pack, Fig. 4 is a perspective view of a housing case, Fig. 5 is a side cross-sectional view showing the interior of a battery monitoring device, Fig. 6 is a diagram showing the configuration of a handset-side wireless antenna, Fig. 7 is a diagram showing a projection surface of the handset-side wireless antenna, Fig. 8 is a diagram showing a schematic change in capacitance in a comparative example, Fig. 9 is a diagram showing a schematic change in capacitance in the first embodiment, and Fig. 10 is a diagram showing a battery monitoring device in a modified example. 14 is a perspective view showing a handset-side wireless antenna in the modified example; FIG. 15 is a diagram showing a metal plate in the modified example; FIG. 16 is a top view showing the inside of a battery pack in the second embodiment; FIG. 17 is a side view showing the inside of a battery pack in the second embodiment; FIG. 18 is a perspective view showing an EC in the second embodiment; 19 is a perspective view showing a U-case, FIG. 20 is a top view showing the inside of the battery pack in the modified example, FIG. 20(a) is a top view showing the inside of the battery pack in the modified example, and FIG. 20(b) is a side view showing the inside of the battery pack in the modified example, FIG. 21 is a top view showing the inside of the battery pack in the modified example, and FIG. 21(a) is a side view showing the inside of the battery pack in the modified example, and FIG. 22 is a top view showing the inside of the battery pack in the modified example, and FIG. 22(b) is a side view showing the inside of the battery pack in the modified example, and FIG. 24 is a top view showing the inside of the battery pack in the modified example; FIG. 25 is a top view showing the inside of the battery pack in the modified example; FIG. 26 is a top view showing the inside of the battery pack in the modified example; FIG. 27 is a top view showing the inside of the battery pack in the modified example; FIG. 28 is a top view showing the inside of the battery pack in the modified example; and FIG. 29 is a diagram showing the electromagnetic wave shield in the modified example.Fig. 30 is a top view showing the inside of the battery pack in the third embodiment, Fig. 31 (a) is a side view showing the inside of the battery pack in the third embodiment, Fig. 31 (a) is a top view showing the inside of the battery pack in a modified example, Fig. 32 is a top view showing the inside of the battery pack in the modified example, Fig. 33 is a cross-sectional view showing the inside of the battery pack in the modified example, and Fig. 34 is a perspective view showing a battery block in the modified example.

[0010] Hereinafter, embodiments of a wireless device and a power supply unit according to the present disclosure will be described in detail with reference to the drawings. Note that, between the embodiments and modifications, the same or equivalent parts in the drawings are designated by the same reference numerals, and their descriptions will not be repeated in principle. Below, we will describe the case where the present invention is applied to a vehicle, but it can also be applied to applications other than vehicles, such as drones and other flying objects, ships, construction machinery, agricultural machinery, etc.

[0011] (First embodiment) <Vehicle> Fig. 1 is a diagram that shows a schematic configuration of a vehicle 10. The vehicle 10 is an electrically powered vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV). The vehicle 10 includes a battery pack 11 (shown as "Battery" in Fig. 1), a power control unit (hereinafter referred to as "PCU") 12 as a power conversion device, a motor 13 (shown as "MG" in Fig. 1) as an electric load, and a vehicle ECU 14 (shown as "ECU" in Fig. 1). Note that PCU is an abbreviation for "Power Control Unit," MG is an abbreviation for "Motor Generator," and ECU is an abbreviation for "Electronic Control Unit."

[0012] The battery pack 11 is mounted on the vehicle 10 as a power supply unit (driving power supply) of the vehicle 10. In Fig. 1, the battery pack 11 is disposed, for example, in a front compartment. However, the battery pack 11 may also be disposed in a rear compartment, under a seat, under the floor, or the like.

[0013] The battery pack 11 is a chargeable and dischargeable DC voltage source that includes a battery pack 20 (described later). The battery pack 11 supplies power to the electrical loads of the vehicle 10. The battery pack 11 also converts power via the PCU 12 and supplies the power to the motor 13. The battery pack 11 is also charged via the PCU 12.

[0014] The PCU 12 performs bidirectional power conversion between the battery pack 11 and the motor 13 in accordance with a control signal from the vehicle ECU 14. The PCU 12 includes, for example, an inverter that converts DC voltage from the battery pack 11 into AC voltage to drive the motor 13, and a converter that boosts the DC voltage supplied to the inverter to a voltage equal to or higher than the output voltage of the battery pack 11.

[0015] The motor 13 is an AC rotating electric machine, such as a three-phase AC synchronous motor with a permanent magnet embedded in the rotor. The motor 13 is driven by the PCU 12 to generate rotational driving force, which is transmitted to the drive wheels. Meanwhile, when braking the vehicle 10, the motor 13 operates as a generator and performs regenerative power generation. The electric power generated by the motor 13 is supplied to the battery pack 11 via the PCU 12 and stored in the battery pack 20.

[0016] The vehicle ECU 14 includes a CPU, ROM, RAM, input / output ports for inputting and outputting various signals, etc. The CPU loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM describes the processing of the vehicle ECU 14. As an example of the main processing of the vehicle ECU 14, the vehicle ECU 14 receives information such as the voltage, current, SOC (State of Charge), and SOH (State of Health) of the battery pack 20 from the battery pack 11, and controls the PCU 12 to instruct the driving of the motor 13 and the charging and discharging of the battery pack 11.

[0017] <Battery Pack> The battery pack 11 will be described in detail. Fig. 2 is a block diagram showing the configuration of the battery pack 11, and Fig. 3 is a plan view showing the schematic arrangement of various elements housed inside the battery pack 11. The battery pack 11 includes a battery pack 20, a junction box 60, a battery monitoring system 100, and a housing case 50 (shown by dashed lines) that houses them. The battery monitoring system 100 is a system that monitors and manages the battery state of the battery pack 20 using wireless communication. The battery monitoring system 100 includes a plurality of battery monitoring devices 30 and a battery control device 40, which communicate wirelessly between them. The battery monitoring devices 30 and the battery control device 40 each correspond to a wireless device.

[0018] In this embodiment, the battery pack 20, the battery monitoring device 30, and the battery control device 40 are housed inside the housing case 50 (battery housing space), but they may also be arranged outside the housing case 50. Alternatively, the housing case 50 may not be provided, and the battery pack 20 and the battery monitoring system 100 may be directly attached to a battery housing space provided in a vehicle body frame or the like. In other words, the vehicle body frame may replace the housing case 50.

[0019] <Battery Assembly> The battery assembly 20 includes a plurality of battery blocks 21 (sometimes referred to as a battery stack or battery module). The battery assembly 20 is configured by connecting the plurality of battery blocks 21 in series and / or parallel. Each battery block 21 includes a plurality of battery cells 22. Each battery cell 22 is configured by a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or the like. Note that a lithium-ion secondary battery is a secondary battery that uses lithium as a charge carrier, and may include not only a typical lithium-ion secondary battery with a liquid electrolyte but also a so-called all-solid-state battery that uses a solid electrolyte. The battery block 21 is configured by connecting the plurality of battery cells 22 in series and / or parallel via bus bars 23. Note that the presence of the battery block 21 is optional, and the battery assembly 20 may be configured by connecting the plurality of battery cells 22 in series and / or parallel. In this embodiment, the battery assembly 20, the battery block 21, and the battery cells 22 correspond to a battery section.

[0020] The battery cells 22 are provided with cell explosion-proof valves (safety valves) 22a that release internal gas when the pressure difference between the inside and outside of the battery case exceeds a predetermined value. In the first embodiment, the cell explosion-proof valves 22a are provided at any location; for example, in FIG. 3 , they are provided on the top surface of the battery cells 22. <Junction Box> The junction box 60 houses one or more relay switches 61. As shown in FIG. 2 , the relay switches 61 are used to connect the battery blocks 21 (or battery cells 22) in series and / or parallel. The relay switches 61 also switch between energizing and de-energizing the battery pack 20, allowing the battery pack 11 to be charged or discharged. The on / off of these relay switches 61 is controlled by the battery control device 40 or the like.

[0021] <Battery Monitoring Device> The battery monitoring device 30 will now be described. Note that each battery monitoring device 30 has a common configuration. The battery monitoring device 30 is also called a satellite battery module (SBM), and is provided for each battery block 21, i.e., for each of a plurality of battery cells 22. As shown in FIG. 2 , each battery monitoring device 30 includes a monitoring IC 31, a slave-side wireless IC 32, a slave-side wireless antenna 33, and the like. These components are mounted on a monitoring circuit board 34 of the battery monitoring device 30, and are housed and fixed in an SBM case 35 (shown by a dashed line in FIG. 2 ) that serves as the housing of the battery monitoring device 30.

[0022] The handset-side wireless IC 32 is connected to the monitoring IC 31 by a wire. The handset-side wireless IC 32 is also connected to the handset-side wireless antenna 33 by a wire.

[0023] The monitoring IC 31, also called a cell monitoring circuit, acquires (senses) battery information of each battery cell 22 constituting the battery block 21 via a physical quantity detection sensor (not shown) or the like. The physical quantity detection sensor is, for example, a voltage sensor, a temperature sensor, a current sensor, or the like, and the battery information includes, for example, voltage information, temperature information, current information, and the like of each battery cell 22. The object monitored by the battery monitoring device 30 may be the battery block 21 or the entire battery pack 20, and may be changed as desired.

[0024] When the monitoring IC 31 receives data (control data as control information) requesting acquisition and transmission of battery information, it acquires the battery information in accordance with the control data and transmits monitoring data (control results) including at least the battery information. Note that the monitoring IC 31 may have a function of performing a fault diagnosis (self-diagnosis) of the circuitry of the battery monitoring device 30, including itself, and transmitting the monitoring data including the diagnosis results together with the acquired battery information.

[0025] The handset-side wireless IC 32 includes an RF circuit, a microcomputer, a front-end circuit, and other components (not shown) for wirelessly transmitting and receiving data. The handset-side wireless IC 32 has a transmission function that modulates data and oscillates at the frequency of an RF signal. At the same time, the handset-side wireless IC 32 has a reception function that demodulates received data. RF is an abbreviation for "radio frequency."

[0026] The slave-side wireless IC 32 modulates the monitoring data including the battery information received from the monitoring IC 31 and transmits it to the battery control device 40 via the slave-side wireless antenna 33. At this time, the slave-side wireless IC 32 adds data necessary for wireless communication, such as communication control information, to the monitoring data including the battery information and transmits it. The data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code. The slave-side wireless IC 32 also has functions such as determining the data size, communication format, and schedule of communication between the battery monitoring device 30 and the battery control device 40, and detecting errors.

[0027] The slave-side wireless IC 32 also receives and demodulates data wirelessly transmitted from the battery control device 40 via the slave-side wireless antenna 33. When the slave-side wireless IC 32 receives control data including, for example, a request to acquire and transmit battery information, it transmits (transfers) the control data via a wired connection to the monitoring IC 31. When the slave-side wireless IC 32 receives monitoring data including battery information from the monitoring IC 31 in response to the request, it modulates response data including the monitoring data and wirelessly transmits the response data to the battery control device 40 via the slave-side wireless antenna 33.

[0028] The handset side wireless antenna 33 converts the RF signal, which is an electrical signal, into radio waves and radiates them into space, and also receives the radio waves propagating through space and converts them into an electrical signal.

[0029] <Battery Control Device> The battery control device 40 is also called a battery ECU or a BMU (Battery Management Unit). The battery control device 40 is configured to be able to wirelessly communicate with each battery monitoring device 30.

[0030] 2, the battery control device 40 includes a battery control MCU 41, a base unit side wireless IC 42, and a base unit side wireless antenna 43. These components are mounted on a control circuit board 44 of the battery control device 40 and are housed and fixed in an ECU case 45 (shown by a dashed line in FIG. 2) that serves as the housing of the battery control device 40.

[0031] The base unit side wireless IC 42 is connected by wire to the battery control MCU 41. The base unit side wireless IC 42 is also connected by wire to the base unit side wireless antenna 43.

[0032] The battery control MCU 41 is configured with a microcontroller unit (microcontroller unit) including a CPU, ROM, RAM, an input / output interface, etc. The CPU of the battery control MCU 41 loads a program stored in the ROM into the RAM and executes it. The program stored in the ROM contains, for example, processes related to battery control.

[0033] As an example of processing related to battery control, the battery control MCU 41 is configured to acquire the terminal voltage (total voltage) of the battery pack 20 via a voltage sensor (not shown). The total voltage of the battery pack 20 is input, for example, from a power supply line connecting a relay switch 61 and an electrical load (an electrical load external to the battery pack 11) in the junction box 60. The voltage sensor may be located inside the junction box 60, inside the battery control device 40, or elsewhere.

[0034] As an example of the main processing of the battery control MCU 41, the battery control MCU 41 transmits control data to the battery monitoring device 30 requesting acquisition and transmission of battery information. The battery control MCU 41 also performs various processes related to monitoring the battery pack 20, battery block 21, and battery cells 22 based on monitoring data including battery information received from the battery monitoring device 30. For example, the battery control MCU 41 may transmit monitoring results (monitoring data) to the vehicle ECU 14, which is a higher-level ECU. In this case, the battery control MCU 41 may calculate the SOC and / or SOH based on the battery information and transmit the battery information including the calculated SOC and SOH to the vehicle ECU 14. The battery control MCU 41 also controls the relay switch 61, which switches between the energized and de-energized states of the battery pack 20, the PCU 12, and the motor 13, based on the monitoring results. The battery control MCU 41 may also transmit an equalization signal to equalize the voltages of the battery cells 22. In this embodiment, the vehicle ECU 14 issues instructions to the PCU 12 to control the charging and discharging of the battery pack 20, but the battery control MCU 41 may also be configured to perform this function. As described above, the battery control MCU 41 monitors and manages the battery pack 20, the battery block 21, and the battery cells 22.

[0035] The master-side wireless IC 42 includes an RF circuit, a microcomputer, a front-end circuit, and the like (not shown) for wirelessly transmitting and receiving data, similar to the slave-side wireless IC 32. The master-side wireless IC 42 has a transmission function and a reception function, similar to the slave-side wireless IC 32.

[0036] The base unit side wireless IC 42 demodulates the received monitoring data including battery information via the base unit side wireless antenna 43 and transmits the demodulated data to the battery control MCU 41. The base unit side wireless IC 42 also modulates the control data received from the battery control MCU 41 with data necessary for wireless communication, such as communication control information, and transmits the modulated data to the battery monitoring device 30 via the base unit side wireless antenna 43. The data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code. The base unit side wireless IC 42 also has functions such as determining the data size, communication format, and schedule of communication between the battery monitoring device 30 and the battery control device 40, and detecting errors.

[0037] The base unit side wireless antenna 43 has the same configuration and function as the slave unit side wireless antenna 33. That is, the base unit side wireless antenna 43 converts an RF signal, which is an electrical signal, into a radio wave and radiates it into space, and also receives the radio wave propagating through space and converts it into an electrical signal.

[0038] <Storage Case> The storage case 50 is made of a conductor such as metal. The storage case 50 is formed in the shape of a metal box, and is roughly rectangular parallelepiped. Note that the storage case 50 may be partially or entirely made of a non-conductive material such as resin. The storage case 50 houses the battery pack 20, the battery monitoring device 30, and the battery control device 40 in the internal battery storage space.

[0039] 4, the housing case 50 is provided with a housing explosion-proof valve 51 that releases gas inside the housing case 50 when the difference in air pressure between the inside and outside of the housing case 50 exceeds a predetermined value. The housing explosion-proof valve 51 is configured, for example, by closing a through-hole 51a that penetrates the housing case 50 with a cover member 51b and welding it to the housing case 50, and is configured so that when the difference in air pressure between the inside and outside of the housing case 50 exceeds a predetermined value, the cover member 51b comes off and the gas escapes through the through-hole 51a. The housing explosion-proof valve 51 corresponds to an opening of the housing case 50.

[0040] To facilitate activation of the housing explosion-proof valve 51, the cover member 51b may be made of resin, or a groove may be formed in the cover member 51b to make it more likely to break when the air pressure increases. The cover member 51b may also be thinner than the thickness of the housing case 50. Furthermore, the housing explosion-proof valve 51 does not necessarily have to be configured by blocking the through-hole 51a with the cover member 51b. For example, a circular or hexagonal groove (thin portion) may be formed in the housing case 50 so that the housing case 50 breaks and forms the through-hole 51a when the air pressure increases. Furthermore, the housing explosion-proof valve 51 does not have to be formed on the top surface, but may be provided on the side or bottom surface. The number and arrangement of the housing explosion-proof valves 51 are arbitrary. However, it is preferable that the housing explosion-proof valves 51 are not provided on a surface that is blocked by the vehicle body or the like and thus makes it difficult for gas to escape.

[0041] Here, the arrangement of the battery pack 20, battery monitoring device 30, battery control device 40, and junction box 60 will be briefly described with reference to FIG. 3 . The lower surface of the housing case 50 is the mounting surface for the vehicle 10. FIG. 3 is a plan view that schematically shows the interior of the battery pack 11 as viewed from above in the vertical direction. As shown in FIG. 3 , a plurality of battery blocks 21 that constitute the battery pack 20 are arranged in the longitudinal direction (X direction in FIG. 3 ) inside the approximately rectangular parallelepiped housing case 50. In each battery block 21, the battery cells 22 that constitute the battery block 21 are arranged so as to be stacked in the lateral direction of the housing case 50 (Y direction in FIG. 3 ). Hereinafter, the longitudinal direction of the housing case 50 may be referred to as the X direction, the lateral direction as the Y direction, and the up-down direction as the Z direction.

[0042] The battery monitoring device 30 and bus bars 23 are disposed on the top surface of each battery block 21 (the surface on the +Z direction side in FIG. 3 ) and secured thereto with screws or the like. The battery control device 40 and junction box 60 are disposed at the very ends in the longitudinal direction (X direction). The battery control device 40 is placed directly above the junction box 60 (on the +Z direction side). The battery control device 40 is desirably disposed so that the parent-side wireless antenna 43 is located near the top surface of the battery block 21, more preferably above the top surface. The arrangement of the battery pack 20, battery monitoring device 30, battery control device 40, and junction box 60 shown in FIG. 3 is merely an example and may be modified as desired. Specific modification examples will be described later.

[0043] In order to perform wireless communication appropriately, it is desirable to maintain the antenna characteristics of the slave-side wireless antenna 33 and the master-side wireless antenna 43 within an appropriate range regardless of the environment. To give a specific example, environmentally friendly reuse of the battery pack 11 is being considered. When the battery pack 11 is reused, it is also being considered to reuse the battery monitoring system 100 and the assembled battery 20 that constitute the battery pack 11 individually. Furthermore, when the battery pack 11 is reused, it is not limited to reusing the battery pack 11 as is, but it is also expected that the battery pack 11 will be reused not only in the same type of vehicle, but also in a different type of vehicle. When the battery pack 11 is reused in a different type of vehicle, the arrangement of the assembled battery 20 and the battery monitoring system 100 may be changed, or the housing case 50 that houses the battery monitoring system 100 may be changed to a different case.

[0044] In such a case, the antenna characteristics of the slave-side wireless antenna 33 and the master-side wireless antenna 43 may be affected. The antenna characteristics may be, for example, VSVR (Voltage Standing Wave Ratio). The effect on the antenna characteristics will be described in detail. At least the portions of the SBM case 35 and the ECU case 45 that face the antennas 33 and 43, specifically, the portions that may serve as paths for radio waves, are generally made of a radio-wave-transparent material, such as resin, to avoid obstructing the radio waves. In this embodiment, the SBM case 35 and the ECU case 45 are made of resin. Therefore, electrostatic capacitance (stray capacitance) occurs between the antennas 33 and 43 and metal components (e.g., the storage case 50 and the battery case of the battery cell 22) present outside the cases 35 and 45 via the cases 35 and 45. This electrostatic capacitance affects the antenna characteristics. Therefore, the shape and size of the antennas 33 and 43 are designed to achieve appropriate antenna characteristics, taking these electrostatic capacitances into consideration.

[0045] The SBM case 35 and the ECU case 45 may be collectively referred to as cases 35 and 45. The slave-side wireless antenna 33 and master-side wireless antenna 43 may be collectively referred to as antennas 33 and 43. The monitoring circuit board 34 and the control circuit board 44 may be collectively referred to as circuit boards 34 and 44.

[0046] However, when the battery monitoring device 30 (or battery control device 40) is reused, if the placement of the battery monitoring device 30 or the configuration of the housing case 50 is changed, the capacitance between them may fluctuate. If the ratio of the amount of variation to the capacitance before the change is too large, the antenna characteristics may be affected, and proper wireless communication may not be possible. Note that the amount of variation refers to the difference between the capacitance before the change and the capacitance after the change, and the ratio of the amount of variation refers to the value calculated by dividing the amount of variation by the capacitance before the change. Hereinafter, the ratio of the amount of variation will be referred to as the variation ratio.

[0047] Therefore, in the first embodiment, the battery monitoring device 30 and the battery control device 40 are designed to prevent the rate of fluctuation from becoming large regardless of changes in the surrounding environment, such as when the battery is reused. This will be explained in detail below with reference to Figure 5. Figure 5 is a side cross-sectional view that schematically shows the interior of the SBM case 35 in the battery monitoring device 30.

[0048] 5, the battery monitoring device 30 has a handset-side wireless antenna 33 mounted on the upper surface of a monitoring circuit board 34 configured in the shape of a substantially rectangular plate, and is housed and fixed in a resin SBM case 35. The SBM case 35 is formed in the shape of a flat rectangular parallelepiped. The handset-side wireless IC 32 is mounted on the lower surface of the monitoring circuit board 34 (the surface opposite to the surface on which the handset-side wireless antenna 33 is mounted).

[0049] The slave-side wireless antenna 33 is a pattern antenna, and includes, for example, an element 33a for radiating radio waves, a ground plate 33b as a wiring pattern arranged opposite the element 33a, and a dielectric 33c interposed between the element 33a and the ground plate 33b, as shown in FIG. 6 . The element 33a is a thin metal conductor and has a shape that combines an L-shaped portion and a rectangular portion. The rectangular portion corresponds to a stub shape (a portion where the wiring branches off). Because it has an open end, the rectangular portion is also referred to as an open stub shape. A signal is input to the element 33a from a power supply point (not shown).

[0050] The ground plate 33b is a thin, long, metal conductor and has a potential corresponding to (equivalent to) the reference potential (e.g., ground) of the monitoring circuit board 34 (in this embodiment, this potential is equivalent to) the reference potential. The element 33a is placed on the ground plate 33b with a dielectric 33c interposed between them. The pattern of the element 33a (shape, size, mainly the length and width of the rectangular portion) is adjusted so that the impedance between the element 33a and the ground plate 33b (the impedance of the slave-side wireless antenna 33) is a desired impedance. The ground plate 33b is disposed on the lower side (the monitoring circuit board 34 side), and the element 33a is disposed on the upper side.

[0051] As shown in FIG. 5 , a metal plate 37 serving as a proximate conductor is disposed on the underside of the monitoring circuit board 34 via an insulating sheet 36. The proximate conductor is a conductor that is close enough to affect the antenna characteristics of the handset-side wireless antenna 33. The effect on the antenna characteristics refers to a change in the impedance of the handset-side wireless antenna 33. More specifically, the proximate conductor is a conductor that is not in electrical contact (connected) with the element 33 a of the handset-side wireless antenna 33 and is located at a distance equal to or less than the wavelength of the lowest frequency in the frequency band used in wireless communication. The metal plate 37 serving as the proximate conductor in this embodiment will now be described in detail.

[0052] The metal plate 37 is disposed on the monitoring circuit board 34 on the side opposite to the side on which the slave-side wireless antenna 33 is installed. The metal plate 37 is flat and disposed with its plane parallel to the monitoring circuit board 34. Specifically, the metal plate 37 is laminated on the monitoring circuit board 34 via the insulating sheet 36. The metal plate 37 is disposed closest to the slave-side wireless antenna 33 compared to other conductors excluding conductors (such as circuit elements) mounted on the monitoring circuit board 34. Specifically, the metal plate 37 is disposed closest to the slave-side wireless antenna 33 in a predetermined direction (the vertical direction of the monitoring circuit board 34) compared to other conductors present inside the SBM case 35. The other conductors present inside the SBM case 35 include, for example, circuit elements (excluding circuit elements mounted on the monitoring circuit board 34), wiring, metal components, etc. The other conductors also include conductors that exist outside the SBM case 35 (such as the housing case 50, the bus bar 23, and the battery case of the battery cell 22). Although the metal plate 37 is described as being flat, flatness refers to a shape that is sufficiently thin compared to other dimensions, and may have some unevenness as well as a shape without any irregularities.

[0053] 7 , when a predetermined direction is defined as the projection direction, the metal plate 37 overlaps at least a portion of the projection surface of the handset-side wireless antenna 33. The predetermined direction is a direction in which the projection surface of the handset-side wireless antenna 33 in the predetermined direction is the largest compared to the projection surfaces in other directions. In this embodiment, the predetermined direction is the vertical direction of the monitoring circuit board 34. The projection surface of the handset-side wireless antenna 33 includes at least the projection surfaces of the element 33 a and the ground plate 33 b. In this embodiment, the area of ​​the metal plate 37 is defined so that the entire projection surface of the handset-side wireless antenna 33 overlaps with the metal plate 37 in the vertical direction. In other words, the area of ​​the metal plate 37 is defined so that when the handset-side wireless antenna 33 is projected from the vertical direction, the entire projection surface is included in the metal plate 37. In this embodiment, the metal plate 37 is configured to cover the entire handset-side wireless IC 32 disposed on the lower surface of the monitoring circuit board 34.

[0054] 5 , the monitoring circuit board 34 and the metal plate 37 are housed and fixed in a stacked state inside the SBM case 35. The size and shape of the SBM case 35 and the fixing position of the monitoring circuit board 34 are determined so that, in the vertical direction of the monitoring circuit board 34, a distance L11 from the top surface of the monitoring circuit board 34 to the top surface of the SBM case 35 is greater than a distance L12 from the slave-side radio antenna 33 to the metal plate 37. The size and shape of the SBM case 35 and the fixing position of the monitoring circuit board 34 are also determined so that, in the vertical direction of the monitoring circuit board 34, a distance L13 from the bottom surface of the metal plate 37 to the bottom surface of the SBM case 35 is greater than a distance L12 from the slave-side radio antenna 33 to the metal plate 37. Therefore, even if the external conditions of the battery monitoring device 30 (such as its layout or the configuration of the storage case 50) change, the metal plate 37 will remain the conductor located closest to the handset side wireless antenna 33 unless the internal configuration of the battery monitoring device 30 is changed.

[0055] The battery monitoring device 30 has been described above, and the battery control device 40 has a similar configuration. Here, referring to FIG. 5 , the internal configuration of the battery control device 40 will be briefly described. In the battery control device 40, the control circuit board 44 has the parent unit side wireless antenna 43 mounted on the upper surface of the control circuit board 44, and in this state is housed and fixed in a resin ECU case 45. The parent unit side wireless IC 42 is mounted on the lower surface of the control circuit board 44 (the surface opposite to the surface on which the parent unit side wireless antenna 43 is mounted).

[0056] The base-side wireless antenna 43 has the same configuration as the handset-side wireless antenna 33. That is, the base-side wireless antenna 43 includes an element 43a for radiating radio waves, a ground plate 43b arranged opposite the element 43a in an insulated state, and a dielectric 43c interposed between the element 43a and the ground plate 43b. Because the element 43a, the ground plate 43b, and the dielectric 43c are configured in the same manner as the handset-side wireless antenna 33, the description of the element 43a, the ground plate 43b, and the dielectric 43c will be omitted and the description thereof will be reused.

[0057] A metal plate 47 serving as a proximal conductor is disposed on the underside of the control circuit board 44 via an insulating sheet 46. The shape, size, and arrangement of this metal plate 47 are similar to those of the metal plate 37 of the battery monitoring device 30. That is, the area of ​​the metal plate 47 is determined so that the entire projection surface of the parent unit side wireless antenna 43 overlaps with the metal plate 47 in the vertical direction of the control circuit board 44. The metal plate 47 also covers the entire parent unit side wireless IC 42 disposed on the underside of the control circuit board 44. For this reason, the description of the metal plate 37 of the battery monitoring device 30 will be reused, and a detailed description of the metal plate 47 will be omitted.

[0058] The control circuit board 44 and the metal plate 47 are then housed and fixed in a stacked state inside the ECU case 45. The ECU case 45 has a configuration similar to that of the SBM case 35, and therefore a description thereof will be omitted.

[0059] Next, the operation of the battery monitoring system 100 configured as above when it is reused will be described with reference to Figures 8 and 9. Here, the explanation will be centered on the battery monitoring device 30, but the battery control device 40 operates in a similar manner.

[0060] First, referring to FIG. 8 , we will explain the change in capacitance in a comparative example in which the metal plate 37 is not present. As described above, the battery monitoring device 30 is housed inside the housing case 50, which is a metal conductor. Therefore, as shown in FIG. 8( a), a capacitance (shown by a dashed line in FIG. 8 ) is generated between the slave-side wireless antenna 33 and a conductor external to the SBM case 35, with the resin SBM case 35 interposed therebetween. The external conductor varies depending on the arrangement of the battery monitoring device 30, and in the case of FIG. 8( a), for simplicity of explanation, it is assumed that the external conductor is the top and bottom surfaces of the housing case 50. In the case of FIG. 8( a), the total capacitance generated between them is, for example, 8 pF (picofarads).

[0061] Then, suppose that this battery monitoring device 30 is reused and housed in a housing case 150 having a different configuration from the housing case 50. For the sake of simplicity, it will be explained here assuming that only the distance between the slave-side wireless antenna 33 of the battery monitoring device 30 and the top surface of the housing case 150 increases (is further apart), as shown in FIG. 8(b) , and all other conditions remain the same.

[0062] The capacitance between the slave-side wireless antenna 33 and the upper surface of the housing case 150 decreases as the distance between them increases. The total capacitance after the change is assumed to be 6 pF, for example. In other words, the amount of change is 2 pF, and the change rate is 25% (= 2 ÷ 8 × 100).

[0063] Next, referring to FIG. 9 , a change in capacitance in the first embodiment in which the metal plate 37 is present will be described. As described above, the battery monitoring device 30 is housed inside the housing case 50, which is a metal conductor. Therefore, in the state before the change, as shown in FIG. 9( a), capacitance (shown by a dashed line in FIG. 9) is generated between the handset-side wireless antenna 33 and a conductor external to the SBM case 35, with the resin SBM case 35 interposed therebetween. The external conductor varies depending on the arrangement of the battery monitoring device 30. In the case of FIG. 9( a), for simplicity of explanation, it is assumed to be the top surface of the housing case 50. Note that, as shown in FIG. 9( a), the metal plate 37, which is a proximal conductor, is disposed on the bottom surface of the monitoring circuit board 34. Therefore, unlike FIG. 8( a), almost no capacitance is generated between the handset-side wireless antenna 33 and the bottom surface of the housing case 50.

[0064] On the other hand, a large capacitance occurs between the handset-side wireless antenna 33 and the metal plate 37. This is because, as described above, the distance between the handset-side wireless antenna 33 and the metal plate 37 is the closest compared to other conductors (e.g., the underside of the casing 50), and the overlapping area is the largest. Therefore, the total capacitance occurring in the case of Fig. 9(a) is much larger than that in the case of Fig. 9(a), and is, for example, 15 pF (picofarads).

[0065] Now, let's assume that this battery monitoring device 30 is reused and stored in the storage case 150, as in FIG. 8(b). In this case, as in the above, only the distance between the slave-side wireless antenna 33 and the top surface of the storage case 150 increases, and the capacitance therebetween decreases. In this case, as in FIG. 8(b), the amount of change (decrease) is 2 pF. Therefore, the total capacitance after the change is 13 pF, and the change rate is approximately 13% (= 2 ÷ 15 × 100).

[0066] In this way, when the battery monitoring device 30 of the first embodiment is reused, the rate of fluctuation can be made smaller than when the metal plate 37 is not present, thereby reducing the effect on the antenna characteristics.

[0067] According to the above embodiment, the following effects are achieved.

[0068] The battery monitoring device 30 and the battery control device 40 each include a metal plate 37, 47, which is a nearby conductor that overlaps at least a portion of the projection surface of the antenna 33, 43 when the projection direction is a predetermined direction. The metal plate 37, 47 generates electrostatic coupling between the antenna 33, 43 and the metal plate 37, 47, generating capacitance. If this capacitance is large, even if stray capacitance occurs between the antenna 33, 43 and another conductor, the proportion of the capacitance between the antenna 33, 43 and the metal plate 37, 47 becomes large (dominant), and even if the capacitance between the antenna 33, 43 and another conductor fluctuates, the proportion of the fluctuation can be reduced. In other words, large changes in capacitance can be prevented, thereby suppressing the impact on antenna characteristics.

[0069] Furthermore, the metal plates 37, 47 are disposed closest to the antennas 33, 43 compared to other conductors (excluding the circuit elements mounted on the circuit boards 34, 44). This increases the capacitance between the metal plates 37, 47 and the antennas 33, 43, making it possible to increase the rate of fluctuation even after the fluctuation. As a result, it becomes possible to reduce the rate of fluctuation.

[0070] Furthermore, the projection surface of the antennas 33 and 43 is the largest compared to the projection surfaces in other directions. This increases the capacitance between the metal plates 37 and 47 and the antennas 33 and 43, making it possible to increase the rate of fluctuation even after the fluctuation. As a result, it becomes possible to reduce the rate of fluctuation.

[0071] The predetermined direction (projection direction) is a direction perpendicular to the monitoring circuit board 34 (or the control circuit board 44 in the case of the battery control device 40). When the metal plates 37, 47 are fixed to the circuit boards 34, 44, the distance and overlapping area between the antennas 33, 43 and the metal plates 37, 47 can be stabilized, making it possible to make the capacitance less likely to fluctuate.

[0072] Furthermore, the metal plates 37, 47 are flat and disposed with their planes parallel to the circuit boards 34, 44. This increases the capacitance between the metal plates 37, 47 and the antennas 33, 43. Furthermore, even if the configuration of the battery pack 11 on the side where the metal plates 37, 47 are disposed, for example, the configuration or arrangement of the assembled battery 20 disposed on the side of the metal plate 37 in the battery monitoring device 30, is changed, the distance and overlapping area between the antennas 33, 43 and the metal plates 37, 47 can be stabilized, making it possible to make the capacitance less likely to fluctuate.

[0073] Furthermore, in the circuit boards 34, 44, the metal plates 37, 47 are arranged on the bottom surface opposite to the top surface on which the elements 33 a, 43 a are arranged, thereby preventing the metal plates 37, 47 from interfering with the radio waves emitted from the elements 33 a, 43 a.

[0074] Furthermore, in the circuit boards 34, 44, the handset-side wireless IC 32 and the base-side wireless IC 42 are arranged on the lower surface opposite to the upper surface on which the elements 33 a, 43 a are arranged, and the metal plates 37, 47 are configured to cover the handset-side wireless IC 32 and the base-side wireless IC 42. The metal plates 37, 47 can block external noise and prevent it from affecting the handset-side wireless IC 32 and the base-side wireless IC 42. Furthermore, because the handset-side wireless IC 32 and the base-side wireless IC 42 are arranged on a different surface from the elements 33 a, 43 a, they can be prevented from adversely affecting each other.

[0075] Furthermore, in a predetermined direction (vertical direction), the entire projection surface of the antennas 33, 43 overlaps with the metal plates 37, 47. This maximizes the overlapping area, making it possible to maximize the proportion of the capacitance between the metal plates 37, 47 and the antennas 33, 43, and reduce the rate of variation.

[0076] The elements 33 a, 43 a have an L-shape and a stub shape, which allows adjustment of the capacitance between the elements 33 a, 43 a and the ground plates 33 b, 43 b, the impedance of the antennas 33, 43, and the capacitance between the elements 33 a, 43 a and the metal plates 37, 47, etc., thereby improving the antenna characteristics.

[0077] Insulating sheets 36, 46 are provided between the antennas 33, 43 (more specifically, the circuit boards 34, 44) and the metal plates 37, 47. As a result, even if a high-voltage source such as the battery cell 22 is placed below the battery monitoring device 30 or the battery control device 40 due to a change in layout, the insulating sheets 36, 46 can prevent leakage of electricity from the antennas 33, 43.

[0078] (Modification of First Embodiment) Hereinafter, a modification in which the configuration of the battery pack 11 is partially changed will be described.

[0079] In the first embodiment, the SBM case 35 and the ECU case 45 are made of resin, but a portion of each may be made of a conductor (such as metal). In this case, for example, as shown in FIG. 10, the underside of the SBM case 35 may be made of metal and function as a metal plate 37. This reduces the number of parts. The ECU case 45 may also be made of a similar material.

[0080] In the first embodiment, if the SBM case 35 and the ECU case 45 are partially or entirely made of a conductor (such as metal), it is necessary to provide a passage portion through which radio waves from the antennas 33 and 43 pass.

[0081] For example, if the SBM case 35 is made of metal, as shown in FIG. 11 , a passage opening 35a may be provided on the side of the SBM case 35 at a position facing the slave-side wireless antenna 33 (near the center in the Y direction in FIG. 11 ). The passage opening 35a is provided closer to the communication partner (battery control device 40) than the slave-side wireless antenna 33 in the radio wave propagation path. The passage opening 35a is also provided on the opposite side of the radio wave propagation path from the metal plate 37 relative to the slave-side wireless antenna 33. Specifically, the passage opening 35a is provided on the side of the SBM case 35 above the monitoring circuit board 34 (on the +Z side) and extends to the top surface. The passage opening 35a may be provided from the side to the top surface of the SBM case 35, or it may be even better if the surface of the top surface of the SBM case 35 facing the slave-side wireless antenna 33 also has a passage opening 35a.

[0082] 11, the passage opening 35a is covered with a resin cover, but it may be configured in any way as long as it allows radio waves to pass through, or it may be left open without any cover. This allows radio waves to be input and output appropriately even when the metal plate 37 is provided.

[0083] Furthermore, the passage opening 35a is preferably provided at a position facing the slave-side wireless antenna 33, and is desirably provided on the opposite side of the metal plate 37. In other words, if the metal plate 37 is provided on the underside (Z- side) of the monitoring circuit board 34, it is desirably provided above (Z+ side) the upper surface on which the slave-side wireless antenna 33 is provided. This allows appropriate input and output of radio waves even when the metal plate 37 is provided.

[0084] The width of the passage opening 35a is set to be equal to or greater than half the wavelength of the radio waves emitted from the slave-side wireless antenna 33. The width may be measured in any direction, either vertically or horizontally. For example, in the direction perpendicular to the Z direction (the projection direction, i.e., the vertical direction of the monitoring circuit board 34), in the modified example shown in FIG. 11 , the width L15 of the passage opening 35a is set to be equal to or greater than half the wavelength of the radio waves emitted from the slave-side wireless antenna 33. This allows an appropriate propagation path for the radio waves passing through the passage opening 35a in the Y direction.

[0085] In the first embodiment, it is desirable that no conductor be arranged on the opposite side of the metal plate 37 from the slave-side wireless antenna 33 (i.e., on the upper side of the monitoring circuit board 34) in the projection direction (the Z direction, which is the vertical direction of the monitoring circuit board 34). However, if any conductor is arranged, it is desirable that the distance between the conductor and the slave-side wireless antenna 33 be equal to or greater than half the wavelength of the radio waves emitted from the slave-side wireless antenna 33. The ECU case 45 may be configured in a similar manner.

[0086] For example, as in the first embodiment, when the upper surface (conductor) of the casing 50 is arranged in the Z direction, the distance between the upper surface of the casing 50 and the handset-side wireless antenna 33 is set to be equal to or greater than half the wavelength of the radio waves emitted from the handset-side wireless antenna 33. This makes it possible to properly ensure a propagation path for the radio waves in the Z direction.

[0087] 11, when the upper surface (conductor) of the SBM case 35 is arranged in the Z direction, the distance L16 between the upper surface of the SBM case 35 and the slave-side wireless antenna 33 is set to be equal to or greater than half the wavelength of the radio waves emitted from the slave-side wireless antenna 33. This makes it possible to appropriately ensure a propagation path for the radio waves passing through the passage opening 35a in the Z direction.

[0088] In the first embodiment, the distance between the top surface of the SBM case 35 and the slave-side wireless antenna 33 is preferably equal to or greater than half the wavelength of the radio waves emitted from the slave-side wireless antenna 33. As a result, even if the external configuration of the SBM case 35 is changed, for example, if a conductor is disposed outside the SBM case 35, the SBM case 35 can ensure that the propagation path in the Z direction (vertical direction) is equal to or greater than half the wavelength of the radio waves. Therefore, the propagation path of the radio waves in the Z direction can be appropriately secured. The ECU case 45 may also be configured in a similar manner.

[0089] In the first embodiment, the shape of the elements 33a and 43a may be changed as desired to obtain desired antenna characteristics. For example, the length and width of the stub shape (rectangular portion) may be changed, or the stub shape may not be provided. Furthermore, the L-shape may not be used. Furthermore, as shown in FIG. 12, the elements 33a and 43a may be provided with a comb-tooth shape 133. This allows the impedance and capacitance to be adjusted to desired values.

[0090] In the first embodiment, the shape of the ground plates 33b, 43b may be changed as desired. For example, as shown in FIG. 13(a), the ground plates 33b, 43b may have a comb-tooth shape 111, or as shown in FIG. 13(b), a meandering shape 112. The ground plates 33b, 43b do not need to face the entire area of ​​the elements 33a, 43a, and may not overlap with part of the elements 33a, 43a, as shown in FIG. 14. This allows for appropriate adjustment of impedance, etc. For convenience of illustration, the dielectrics 33c, 43c are omitted from FIG. 14.

[0091] Regardless of the shape of the elements 33a, 43a or the ground plates 33b, 43b, the projection surface of the antennas 33, 43 includes at least the projection surfaces of the elements 33a, 43a and the projection surfaces of the ground plates 33b, 43b.

[0092] In the first embodiment, the metal plates 37, 47 are configured to cover the lower surfaces of the circuit boards 34, 44. However, the size of the metal plates 37, 47 may be arbitrarily changed as long as a portion of the projection surface of the antennas 33, 43 overlaps with the metal plates 37, 47. For example, as shown in FIG. 15( a), approximately half of the projection surface of the antennas 33, 43 may overlap with the metal plates 37, 47. Alternatively, as shown in FIG. 15( b), the projection surface of the antennas 33, 43 and the metal plates 37, 47 may have the same area but only a portion of the projection surface may overlap. Furthermore, although not shown, the metal plates 37, 47 may be provided so that they completely match the projection surface of the antennas 33, 43. It is desirable to set the size of the metal plates 37, 47 so that more than half of the projection surface of the antennas 33, 43 overlaps with the metal plates 37, 47.

[0093] Second Embodiment A battery pack according to a second embodiment will be described below.

[0094] In the battery monitoring system 100 that uses wireless communication as in the first embodiment, communication is affected by electromagnetic noise, so an electromagnetic wave blocking material (a metal conductor in the first embodiment) that absorbs or reflects external electromagnetic noise is used in the housing case 50 (the housing of the battery pack 11) that houses the battery monitoring system 100. Note that an example of a document that describes the use of an electromagnetic wave absorbing material in a housing case is the patent document shown in JP-T-2020-510956.

[0095] However, the source of electromagnetic noise (noise source) is not necessarily located outside the housing case 50, but may be located inside the housing case 50. For example, in the first embodiment, a main noise source located inside the housing case 50 of the battery pack 11 is a junction box 60 that has a relay switch 61 and switches current connections. Therefore, when wireless communication is used inside the housing case 50, it is necessary to suppress the influence of electromagnetic noise from noise sources inside the housing case 50.

[0096] The second embodiment has been made in view of the above circumstances, and its main purpose is to suppress the influence of noise generated inside the accommodating case 50. This will be described in detail below.

[0097] As described in the first embodiment, the battery control device 40 is disposed near (directly above, in the first embodiment) the junction box 60 in order to obtain the total voltage (terminal voltage) of the battery pack 20 from the junction box 60. The relay switch 61 of the junction box 60 is connected to an external electrical load (such as an inverter), making it susceptible to noise being introduced via wiring. The relay switch 61 can also generate electromagnetic noise when switched. For this reason, the junction box 60 can be considered a noise source inside the housing case 50 (battery housing space).

[0098] 16 and 17 , in the second embodiment, an electromagnetic wave shield 201 serving as an electromagnetic wave blocking member is provided between the battery control device 40 and the junction box 60 serving as a noise source, thereby blocking electromagnetic noise from reaching the battery control device 40. In addition, a battery cell 22 serving as an electromagnetic wave blocking member is provided between the battery monitoring device 30 and the junction box 60 serving as a noise source, thereby blocking electromagnetic noise from reaching the battery monitoring device 30.

[0099] First, the arrangement of the battery monitoring device 30, the battery control device 40, and the junction box 60 in the second embodiment will be described. Fig. 16 is a top view (viewed from the Z+ direction) of the interior of the storage case 50 in the second embodiment, and Fig. 17 is a side view (viewed from the Y direction) showing the interior of the storage case 50 in the second embodiment.

[0100] As shown in Fig. 16 , multiple battery blocks 21 are arranged side by side in the longitudinal direction (X direction) of the housing case 50. The battery control device 40 and junction box 60 are arranged between one side wall 50a in the X direction of the housing case 50 and the side surface of the battery pack 20 (more specifically, the battery block 21 arranged at one end of the X direction). The battery control device 40 is arranged directly above the junction box 60. Furthermore, as shown in Fig. 17 , the battery control device 40 and junction box 60 are arranged below the top surfaces of the battery blocks 21.

[0101] In this embodiment, the junction box 60 is provided directly below the battery control device 40, and therefore an electromagnetic wave shield 201 is provided below the battery control device 40. The electromagnetic wave shield 201 is made of a conductive material. In this embodiment, the electromagnetic wave shield 201 is made of a thin metal plate.

[0102] The electromagnetic wave shield 201 is sized to cover at least parts of the battery control device 40 that are susceptible to electromagnetic noise, such as the battery control MCU 41, the parent device side wireless IC 42, and the parent device side wireless antenna 43. It is desirable that the electromagnetic wave shield 201 be sized to cover the entire bottom surface of the control circuit board 44, specifically the bottom surface of the ECU case 45, and in the second embodiment, it is configured to cover almost the entire top surface of the junction box 60.

[0103] In the battery control device 40, the base unit wireless antenna 43 is mounted on the upper surface of the control circuit board 44 and is configured to radiate radio waves upward. An example of the radio waves radiated from the base unit wireless antenna 43 is shown by a dashed line in Figures 16 and 17. This prevents the radio waves from being blocked by the electromagnetic wave shield 201. In the frequency band used for wireless communication, the radio wave intensity of the radio waves radiated from the battery control device 40 and input to the battery monitoring device 30 with which it communicates is set so that the radio wave intensity is stronger than the radio wave intensity of electromagnetic noise generated from the junction box 60.

[0104] On the other hand, as shown in FIG. 16 , the multiple battery monitoring devices 30 are arranged between one side wall 50b in the short-side direction (Y direction) of the housing case 50 and the side of the battery pack 20 (more specifically, one side surface of each battery block 21 in the Y direction). Also, as shown in FIG. 17 , the battery monitoring devices 30 are arranged below the top surfaces of the battery blocks 21. Note that, for space reasons, the battery monitoring devices 30 are arranged vertically (the vertical direction of the monitoring circuit board 34 corresponds to the Y direction), but the arrangement may be changed as desired. The slave-side wireless antenna 33 is installed on the surface opposite the battery block 21 in the Y direction (the side of the side wall 50b of the housing case 50). Also, as shown in FIG. 17 , the slave-side wireless antenna 33 is installed above the junction box 60 in the Z direction.

[0105] In this way, the battery block 21 is disposed between the junction box 60 and the battery monitoring device 30, and the battery case of the battery block 21 (or the battery case of the battery cell 22) is made of a metal conductor that blocks electromagnetic noise. Therefore, the battery case functions as an electromagnetic wave blocking member interposed between the junction box 60 and the battery monitoring device 30. In the frequency band used in wireless communication, the radio wave intensity of the radio waves radiated from the battery monitoring device 30 and input to the battery control device 40, which is the communication partner, is set so that the radio wave intensity is stronger than the radio wave intensity of the electromagnetic wave noise generated from the junction box 60.

[0106] The handset-side wireless antenna 33 is disposed above the monitoring circuit board 34 in the Z direction and is configured to radiate radio waves (shown by dashed lines) upward. As a result, radio waves radiated upward from the battery monitoring device 30 are reflected by the top surface (ceiling) of the housing case 50 or the like and are input to the battery control device 40. The radio wave paths shown by dashed lines in FIGS. 16 and 17 are merely examples; radio waves radiated from the battery monitoring device 30 may first be reflected by the side wall 50b of the housing case 50, then repeatedly reflected by the top surface of the housing case 50 or the battery case, before being input to the battery control device 40. Similarly, radio waves radiated upward from the battery control device 40 may be reflected by the top surface of the housing case 50 or the like and be input to the battery monitoring device 30. This radio wave path is also merely an example; radio waves radiated from the battery control device 40 may repeatedly be reflected by the top surface of the housing case 50 or the battery case, before being reflected by the side wall 50b of the housing case 50 and being input to the battery monitoring device 30.

[0107] It should be noted that there is a possibility that electromagnetic noise emitted from the side of the junction box 60 may be reflected by the side walls 50a, 50b of the housing case 50, and may travel around the side of the battery block 21 to reach the battery monitoring device 30 or the battery control device 40. To suppress the effects of such electromagnetic noise, the side of the junction box 60, the side of the battery monitoring device 30, or the side of the battery control device 40 may be covered with an electromagnetic shield.

[0108] According to the above embodiment, the following effects are achieved.

[0109] An electromagnetic wave shield 201 is interposed between the battery control device 40 and the junction box 60. This makes it possible to suppress the influence of electromagnetic noise from the junction box 60 on the battery control device 40. Similarly, a battery cell 22 (battery case) that functions as an electromagnetic wave shielding member is interposed between the battery monitoring device 30 and the junction box 60. This makes it possible to suppress the influence of electromagnetic noise from the junction box 60 on the battery monitoring device 30.

[0110] In the battery storage space of the storage case 50, the slave-side wireless antenna 33 of the battery monitoring device 30 and the master-side wireless antenna 43 of the battery control device 40 are located above the junction box 60, and communication is carried out by reflecting radio waves off the top surface of the storage case 50. This prevents radio waves from being blocked by the junction box 60, allowing for appropriate wireless communication.

[0111] The handset-side wireless antenna 33 and the base-side wireless antenna 43 are disposed above the electromagnetic wave shield 201, and the junction box 60 is separated by the electromagnetic wave shield 201. Therefore, even if an electromagnetic wave shield is not provided on the side, noise generated from the junction box 60 is less likely to reach the antennas 33 and 43.

[0112] The radio wave intensity of the radio waves emitted from the battery monitoring device 30 and the battery control device 40 is stronger than the radio wave intensity of the electromagnetic noise generated from the junction box 60. Therefore, the influence of the electromagnetic noise can be suppressed.

[0113] (Modification of Second Embodiment) Hereinafter, a modification of the second embodiment in which the configuration of the battery pack 11 is partially changed will be described.

[0114] In the second embodiment, the SBM case 35 and the ECU case 45 are made of resin. However, portions of these cases may be made of an electromagnetic wave shielding material (such as metal). In this case, it is desirable that the surface of the SBM case 35 or the ECU case 45 that faces the junction box 60 be made of an electromagnetic wave shielding material. For example, as shown in FIG. 17 , if the junction box 60 is located directly below the battery control device 40, the underside of the ECU case 45 may be made of a metal conductor and function as an electromagnetic wave shield (electromagnetic wave shielding material). In this case, the electromagnetic wave shield 201 can be omitted, thereby reducing the number of parts. Similarly, the left side surface of the SBM case 35 (the side surface facing the junction box 60) may be made of an electromagnetic wave shielding material.

[0115] In the second embodiment, if the SBM case 35 and the ECU case 45 are partially or entirely made of a conductor (such as metal), it is necessary to provide a passage portion through which radio waves from the antennas 33 and 43 pass.

[0116] For example, in the case of a battery control device 40 in which the radio wave propagation path is located above (Z+ direction) and the electromagnetic wave shield 201 is located directly below, as shown in Figures 16 and 17, a passage opening 245a may be provided on the top surface of the ECU case 45 at a position opposite the parent unit side wireless antenna 43 (near the right side in Figure 18), as shown in Figure 18.

[0117] 18, the passage opening 245a is covered with a resin cover, but it may be configured in any way as long as it allows radio waves to pass through, and it may also be an open opening without any cover. The passage opening 245a is arranged so as to be closer to the communication partner than the antennas 33 and 43 in the radio wave propagation path, but not to be located on the junction box 60 side. That is, in the example of FIG. 18, the passage opening 245a of the ECU case 45 is arranged on the top surface (the surface opposite to the junction box 60 side).

[0118] In this case, the underside of the ECU case 45 may be made of a conductor such as metal to function as an electromagnetic wave blocking member (electromagnetic wave shield), thereby eliminating the need to provide an electromagnetic wave blocking member (such as the electromagnetic wave shield 201) outside the battery control device 40 and reducing the number of parts.

[0119] 16 and 17 , in the case of a battery monitoring device 30 in which the radio wave propagation path is located above (in the Z+ direction) and the battery cells 22 (battery blocks 21) are arranged on the side surface in the Y direction, a passage opening may be provided on the top surface (surface in the Z+ direction) of the SBM case 35 at a position facing the slave-side wireless antenna 33 (near the center in the X direction). Note that, if a propagation path is assumed in which radio waves are reflected by the side wall 50 b of the housing case 50 and input / output from the side wall 50 b of the battery monitoring device 30, a passage opening may be provided on the side surface of the SBM case 35 (on the side surface of the side wall 50 b) at a position facing the slave-side wireless antenna 33. It is also desirable that the passage opening provided in the SBM case 35 open in a direction different from the side of the battery cells 22 that function as an electromagnetic wave blocking member.

[0120] The antennas 33 and 43 of the second embodiment may be directional antennas that emit directional radio waves. A directional antenna is an antenna that emits strong radio waves in a predetermined direction. When a directional antenna is used, it is desirable that the direction of the antenna is determined so that the direction in which the radio waves emitted from the directional antenna are strong is toward the communication partner, but is not toward a noise source or an electromagnetic wave blocking material.

[0121] For example, as shown in Figures 16 and 17, in the case of a battery control device 40 in which a junction box 60 and an electromagnetic wave shield 201 are placed directly below and the radio wave propagation path is provided on the upper side, it is desirable that the direction of the directional antenna be determined so that the direction in which the radio waves radiated from the directional antenna are strong is toward the upper side (the side of the battery monitoring device 30 on the propagation path) but not toward the lower side (the side of the junction box 60, etc.).

[0122] 16 and 17 , in the case of a battery monitoring device 30 in which the battery cells 22 (battery blocks 21) are arranged on one side in the Y direction and the side wall 50b of the housing case 50 is arranged on the other side, with the radio wave propagation path being provided on the upper side, the direction of the directional antenna is determined so that the direction in which the radio waves radiated from the directional antenna are strong is toward the upper side (the side of the battery control device 40 on the propagation path) but not toward the side (the side of the battery cells 22 or side wall 50b). Note that, if a propagation path is assumed in which radio waves are reflected by the side wall 50b of the housing case 50 and input / output from the side of the side wall 50b of the battery monitoring device 30, the direction of the directional antenna may be determined so that the direction in which the radio waves radiated from the directional antenna are strong is toward the side surface of the SBM case 35 (the side surface of the side wall 50b).

[0123] This prevents radio waves from the directional antenna from being blocked by the influence of electromagnetic wave blocking members or noise sources, allowing for proper wireless communication.

[0124] In the second embodiment and its modifications, the arrangement of the battery block 21 (including the battery cells 22), the battery monitoring device 30, the battery control device 40, and the junction box 60 may be changed as desired. Examples of changes to the arrangement will be described below with reference to FIGS. 19 to 23 .

[0125] In the modified example shown in Fig. 19 , the battery control device 40 and the junction box 60 are disposed between one side wall 50a of the housing case 50 in the X direction and the side surface of the battery pack 20. The battery control device 40 is disposed side by side with the junction box 60 in the Y direction. Note that in Fig. 19 , the junction box 60 is disposed on the left side and the battery control device 40 is disposed on the right side in the Y direction. In the modified example shown in Fig. 19 , an electromagnetic wave shield 201 is disposed between the junction box 60 and the battery control device 40. That is, the electromagnetic wave shield 201 is provided so as to cover almost the entire side surface of the junction box 60 on the battery control device 40 side in the Y direction (the right side surface in Fig. 19 ).

[0126] In the modification of FIG. 19 , when the ECU case 45 is provided with a passage 245a for passing radio waves as in the above modification, the passage 245a may be provided so as to face the communication partner but not face the junction box 60 or the electromagnetic wave shield 201, which are noise sources. For example, the passage 245a may be provided on the top surface of the ECU case 45 or on the side surface of the battery monitoring device 30 in the Y direction (the right side surface in FIG. 19 ), at a position corresponding to the master-side wireless antenna 43. Furthermore, when a directional antenna is employed in the battery control device 40, the direction of the directional antenna may be determined so that the direction of strong radio wave strength faces the communication partner but does not face the junction box 60 or the electromagnetic wave shield 201. For example, in the example of FIG. 19 , the direction of strong radio wave strength may be determined so as to face upward or to the right in FIG. 19 .

[0127] Similarly, when providing a passageway in the SBM case 35 to allow radio waves to pass through, the passageway may be provided on the top surface of the SBM case 35, on the side surface on the battery control device 40 side in the X direction, or on the side surface on the side wall 50b of the storage case 50 in the Y direction, at a position corresponding to the slave-side wireless antenna 33. Furthermore, when a directional antenna is used for the battery monitoring device 30, in the example of Fig. 19, the antenna may be oriented so that the direction in which radio wave intensity becomes stronger is upward, or toward the battery monitoring device 30 in the propagation path.

[0128] In the modified example shown in FIG. 20( a), the battery blocks 21 (or battery cells 22) are aligned in two rows in the X direction with a gap in the center in the short direction (Y direction) of the housing case 50. Hereinafter, the central gap in the Y direction will be referred to as a central passage 210. Also, as shown in FIG. 20( b), at one end of the housing case 50 in the X direction, the battery blocks 21 (or battery cells 22) are stacked in multiple stages in the Z direction (two stages in FIG. 20). Note that a small gap 211 is formed in the X direction between the battery blocks 21 stacked in multiple stages and the battery blocks 21 in a single stage.

[0129] The battery control device 40 is disposed in the central passage 210. The battery control device 40 can be disposed anywhere in the central passage 210, and in Fig. 20(a) it is disposed near the battery blocks 21 that are stacked in multiple stages.

[0130] The battery monitoring device 30 is fixed to the side surface of each battery block 21 facing the central passage 210. Also, as shown in Figure 20(b), a battery monitoring device 30 is fixed to the side surface (the side surface on the battery control device 40 side in the X direction) of each battery block 21 that is stacked in multiple stages. In this modification, the battery monitoring device 30 is fixed in a vertical position (the vertical direction of the monitoring circuit board 34 is the Y direction or the X direction), but the placement may be changed as desired.

[0131] The battery monitoring devices 30 and battery control devices 40 arranged in the central passage 210 perform wireless communication using the central passage 210 as a propagation path. The battery monitoring devices 30 fixed to the side surfaces of each of the battery blocks 21 stacked in multiple stages perform wireless communication using the gaps 211 formed between the stacked battery blocks 21 and each battery block 21 in a single stage, and the space above the battery blocks 21 as propagation paths.

[0132] The junction box 60 is placed at any position in the central passage 210. The junction box 60 is covered with a metal case (electromagnetic wave shielding member), which can prevent electromagnetic noise from leaking outside the junction box 60. This makes it possible to suppress the effects of electromagnetic noise generated from the junction box 60, even when the central passage 210 is used as a radio wave propagation path.

[0133] In the modified examples of Figures 21(a) and 21(b), the battery blocks 21, battery monitoring devices 30, and junction boxes 60 are arranged in the same manner as in the modified example of Figure 20. As shown in Figure 21(a), the battery control device 40 is fixed to the side surface in the Y direction of the multiple stages of battery blocks 21. The battery control device 40 uses the space above the battery blocks 21 as a propagation path for radio waves.

[0134] 22(a) and 22(b), a storage case 250 that is L-shaped (step-shaped) in side view (when viewed from the Y direction) is used, as shown in Fig. 22(b). The battery blocks 21 (or battery cells 22) are aligned in the X direction in one or more rows in the widthwise direction (Y direction) of the storage case 250. Furthermore, at one end of the lengthwise direction (X direction) of the storage case 250, the battery blocks 21 (or battery cells 22) are stacked in multiple rows (two rows in Fig. 22) in the vertical direction (Z direction).

[0135] 22(b), a battery monitoring device 30 is fixed to the side surface (one side surface in the Y direction) of each battery block 21. A battery control device 40 is fixed to the side surface (the same side surface to which the battery monitoring device 30 is fixed) of the battery blocks 21 stacked in two layers. The battery control device 40 is disposed below the upper battery block 21 so as not to interfere with the battery monitoring device 30.

[0136] The battery monitoring device 30 and the battery control device 40 communicate wirelessly using the space between the side wall 250b in the Y direction and the battery block 21 in the storage case 250, i.e., the lateral space in the Y direction within the interior of the storage case 250 (battery storage space).

[0137] 22( a), the junction box 60 is fixed to the X-direction side surface of the upper battery block 21 of the two-tiered stacked battery blocks 21. In this modification, an electromagnetic wave shield 201 is provided to cover the Y-direction side surface of the junction box 60 on the side of the battery monitoring device 30 and battery control device 40. This makes it possible to suppress radiation of electromagnetic wave noise from the side surface of the junction box 60 toward the battery monitoring device 30 and battery control device 40.

[0138] The X-direction side surface of the junction box 60 is covered by the side wall of the battery block 21 or the housing case 250. This prevents electromagnetic noise from being emitted from the X-direction side surface of the junction box 60.

[0139] 23( a) and 23(b) show modified examples of FIG. 22. As shown in FIG. 23(a), the junction box 60 and the battery control device 40 may be disposed at one end of the housing case 250 in the X direction (the opposite side from the two-tiered battery blocks 21). In this case, the battery control device 40 is disposed directly above the junction box 60, and an electromagnetic wave shield 201 is disposed to cover the top surface of the junction box 60. The battery control device 40 and the battery monitoring device 30 then use the space between the side wall 250b of the housing case 250 in the Y direction and the battery block 21 as a radio wave propagation path to perform wireless communication.

[0140] 23(b), similar to FIG. 23(a), the junction box 60 and battery control device 40 are disposed at one end of the housing case 250 in the X direction (the opposite side from the second-tiered battery blocks 21). Similarly to FIG. 23(a), the battery control device 40 is disposed directly above the junction box 60 in FIG. 23(b), and an electromagnetic wave shield 201 is disposed to cover the top surface of the junction box 60. In the example of FIG. 23(b), the battery monitoring device 30 is disposed on the top surface of each battery block 21. The battery monitoring device 30 is disposed on the side surface of the upper battery block 21 in the X direction. In the example of FIG. 23(b), the battery control device 40 and battery monitoring device 30 communicate wirelessly using the space above the battery blocks 21 as a radio wave propagation path.

[0141] In the second embodiment and its modified examples, as shown in Fig. 24, blade cells 260 in the shape of long plates extending in the Y direction of the casing 50 may be used as battery cells. These blade cells 260 are stacked in the X direction of the casing 50. The electrode terminals of the blade cells 260 are arranged side by side on one or both sides in the Y direction. The electrode terminals of the blade cells 260 may also be provided on the top surface.

[0142] A plurality of battery monitoring devices 30 are arranged on one side of the blade cells 260 in the Y direction (the right side in FIG. 24 ). Furthermore, a junction box 60 and a battery control device 40 are arranged side by side in the Y direction at one end of the housing case 50 in the X direction. As shown in FIG. 24 , an electromagnetic wave shield 201 is arranged between the junction box 60 and the battery control device 40, as described above, and the battery control device 40 is arranged on the side of the battery monitoring device 30. The battery monitoring devices 30 and the battery control device 40 communicate wirelessly using the space on the side of the housing case 50 in the Y direction and above the blade cells 260 as radio wave propagation paths.

[0143] Furthermore, by arranging the electrode terminals and busbars 23 of the blade cell 260 on the side opposite to the side on which the battery monitoring device 30 is arranged in the Y direction (the left side in Figure 24), the effects of electromagnetic noise generated from the electrode terminals and busbars 23 can be suppressed.

[0144] In the second embodiment and its modified examples, as shown in Fig. 25 , the battery blocks 21 may be aligned along the short side (Y direction) so as to form multiple rows (four rows in Fig. 25 ) in the long side (X direction) of the housing case 50. In this case, the battery cells 22 constituting each battery block 21 may be stacked in the Y direction so that their electrode terminals are gathered at one end in the X direction.

[0145] 25, a communication path 270 may be provided in the center of the housing case 50 in the Y direction. The battery blocks 21 are arranged symmetrically with respect to the communication path 270. Furthermore, as shown in the third row from the top in FIG. 25, when the number of battery blocks 21 arranged in the Y direction is smaller than in the other rows, the battery blocks 21 are arranged closer to the central communication path 270.

[0146] In Figure 25, the battery monitoring device 30 is arranged along the communication path 270. The battery control device 40 is arranged at one end of the housing case 50 in the X direction, next to the junction box 60 in the Y direction. An electromagnetic wave shield 201 large enough to cover almost the entire side surface of the junction box 60 or the side surface of the ECU case 45 is provided between the battery control device 40 and the junction box 60. The battery control device 40 is desirably arranged closer to the communication path 270 than the junction box 60. In Figure 25, the battery control device 40 is arranged on the communication path 270. The battery control device 40 and the battery monitoring device 30 communicate wirelessly using the communication path 270 as a radio wave propagation path.

[0147] 25, the electrode terminals of the battery cells 22 that make up the battery block 21 are preferably provided on a surface that does not face the battery monitoring device 30 or the battery control device 40, such as the top surface. This makes it possible to suppress the effects of noise that may be generated from the electrode terminals and bus bars 23.

[0148] In the second embodiment and its variations, the shape of the housing 50, 150, 250 may be changed as desired. For example, a housing 251 shown in Fig. 26(a) has a housing space 252 in a protrusion 250a that protrudes longitudinally from a side wall 50a. The housing space 252 houses the battery control device 40 and junction box 60. The opening of this housing space 252 is closed by a partition plate 253 made of a material (e.g., resin) that allows radio waves to pass through, separating it from a space 254 that houses the battery block 21.

[0149] The battery control device 40 allows radio waves to pass through the partition plate 253, and communicates wirelessly with the battery monitoring device 30 located near the battery block 21. The junction box 60 may be surrounded by a metal case (electromagnetic wave blocking member).

[0150] The partition plate 253 of the accommodation space 252 may be made of an electromagnetic wave blocking material. In this case, an electromagnetic wave shield 201 may be provided between the junction box 60 and the battery control device 40, and only the parent unit side wireless antenna 43 may be placed in the space accommodating the battery block 21. Alternatively, a passage portion that allows radio waves to pass through may be provided in the partition plate 253, and radio waves may be input or output via this passage portion.

[0151] As in the case of a storage case 255 shown in FIG. 26(b), the protrusion 250a (i.e., the storage space 252) may be provided on the top surface instead of the side wall 50a.

[0152] In the second embodiment and its modified examples, the arrangement may be changed as shown in Fig. 27. The battery blocks 21 are aligned along the longitudinal direction (X direction) of the housing case 50 so as to form two rows in the lateral direction (Y direction). The battery block 21 is configured by stacking a plurality of battery cells 22 in the X direction. The electrode terminals of each battery cell 22 are arranged on one or both sides of the Y direction and are connected to each other to form the battery block 21.

[0153] A central passage 280 is provided in the center in the Y direction, and a plurality of battery monitoring devices 30 are arranged in the central passage 280. In Fig. 27, the devices are placed vertically, but the placement may be arbitrary.

[0154] 27 , the number of battery blocks 21 in the left column is one less than the number of battery blocks 21 in the right column, and a storage space is provided at the end in the X direction. The battery control device 40 and junction box 60 are disposed in this storage space. In the modification shown in FIG. 27 , the junction box 60 is provided with a metal case (electromagnetic wave blocking member), but an electromagnetic wave shield may also be provided to separate the battery control device 40 and the battery monitoring device 30.

[0155] In the second embodiment and its modified examples, the arrangement may be changed as shown in Fig. 28. The battery blocks 21 are aligned along the longitudinal direction (X direction) of the housing case 50 so as to form two rows in the lateral direction (Y direction). The battery block 21 is configured by stacking a plurality of battery cells 22 in the Y direction. The electrode terminals of each battery cell 22 are provided on the top surface (Z+ direction) and are connected to each other to form the battery block 21.

[0156] A central passage 290 is provided in the center in the Y direction, and a plurality of battery monitoring devices 30 are arranged in the central passage 290. In Fig. 28, the devices are placed vertically, but the placement may be arbitrary.

[0157] In Fig. 28 , a junction box 60 is disposed near the center in the Y direction at the end of the housing case 50 in the X direction. The battery control device 40 is disposed adjacent to the junction box 60. In the modified example shown in Fig. 28 , the junction box 60 is provided with a metal case (electromagnetic wave blocking member) to prevent electromagnetic noise from leaking to the outside. An electromagnetic wave shield may be provided to separate the battery control device 40 and the battery monitoring device 30. In Fig. 28 , the space above the battery block 21 is used as a propagation path for radio waves.

[0158] In the second embodiment and its modifications, the configuration of the electromagnetic wave blocking member may be changed as desired. For example, as shown in Fig. 29(a), a metal case 292 housing a circuit board 291 may be used as an electromagnetic wave blocking member interposed between the battery control device 40 (or the battery monitoring device 30) and the junction box 60, which is a noise source. Note that the circuit board 291 in Fig. 29(a) is, for example, a circuit board equipped with an abnormality monitoring device that detects a current value and issues a command to shut off the current if the current value is abnormal.

[0159] In the second embodiment and its modified example, as shown in FIG. 29B, a heat sink 293 (conductor) employed in the junction box 60 may be used as an electromagnetic wave blocking member.

[0160] In the second embodiment and its modified examples, the junction box 60 is identified as a noise source. However, other noise sources may be identified and separated by an electromagnetic wave shielding member. Other noise sources than the junction box 60 include, for example, the bus bar 23 and power terminals through which current can flow from an external electrical load. If the bus bar 23 and power terminals are considered noise sources, they may be covered with a metal case or the like. Any noise source may be identified as long as the radio wave intensity of the radiated electromagnetic noise is equal to or greater than a predetermined threshold.

[0161] In the above embodiments and modifications, the electromagnetic wave blocking member is not limited to metal, but may be coated with conductive paint or made of metal fibers. The electromagnetic wave blocking member may be made of metals such as copper or aluminum, which have high electromagnetic wave reflection loss, or iron, which has high electromagnetic wave absorption loss. While electromagnetic wave noise refers to noise in the frequency band of approximately 300 Hz to 3 THz that interferes with RF signals, it may also include electromagnetic wave noise in other frequency bands.

[0162] In the second embodiment, the metal plates 37 and 47 that are proximate conductors that are electrostatically coupled to the antennas 33 and 43 may not be provided.

[0163] Third Embodiment A battery pack according to a third embodiment will be described below.

[0164] As described in the first embodiment, the battery pack 11 and the battery cells 22 are generally provided with an explosion-proof valve for releasing gas when the internal pressure (more specifically, the pressure difference between the inside and outside) exceeds a specified value. Explosion-proof valves are described, for example, in Japanese Patent Application Laid-Open No. 2020-074279. However, when wireless communication is performed, if gas is ejected from such an explosion-proof valve, there is a concern that the gas may affect the wireless communication.

[0165] The third embodiment has been made in consideration of the above circumstances, and its main purpose is to provide a battery pack 11 (power supply unit) that can suppress the impact on wireless communication even if gas is ejected from the explosion-proof valve.

[0166] Hereinafter, the battery pack 11 of the third embodiment will be described in detail with reference to FIG.

[0167] As shown in Figure 30 , multiple battery blocks 21 are arranged side by side in the longitudinal direction (X direction) of the housing case 50. The battery control device 40 and junction box 60 are arranged between one side wall 50a in the X direction of the housing case 50 and the side surface of the battery pack 20 (more specifically, the battery block 21 arranged at one end of the X direction). The battery control device 40 is arranged side by side with the junction box 60 in the Y direction. In Figure 30 , the battery control device 40 is arranged near the right side wall 50b.

[0168] In the third embodiment, the cell explosion-proof valves 22a are provided on the top surface of each battery cell 22 (see FIG. 30 ), as in the first embodiment, and the housing explosion-proof valves 51 are provided on the top surface of the storage case 50 (shown by dashed lines), as in the first embodiment. The housing explosion-proof valves 51 are provided facing (overlapping) each cell explosion-proof valve 22a in the vertical direction, but their placement can be changed as desired. The size, number, and shape of the housing explosion-proof valves 51 can also be changed as desired. For example, a single large housing explosion-proof valve 51 may be provided in the center of the top surface of the storage case 50. Although the battery control device 40 is shown installed vertically, the placement can be arbitrary.

[0169] 30, the battery monitoring devices 30 are disposed in the space between the right sidewall 50b in the Y direction and the right side surface of each battery block 21. The battery monitoring devices 30 are placed vertically, but may be placed in any other manner. The battery control device 40 and the battery monitoring devices 30 communicate wirelessly using the space on the right side of the battery block 21 as a radio wave propagation path (shown by the dashed line).

[0170] According to the above embodiment, the following effects are achieved.

[0171] A cell explosion-proof valve 22a is provided on the top surface of each battery cell 22. Therefore, gas from the cell explosion-proof valve 22a is discharged above the battery block 21. A housing explosion-proof valve 51 is provided on the top surface of the storage case 50. Therefore, gas discharged above the battery block 21 is discharged from the housing explosion-proof valve 51, making it difficult for gas to be discharged to the side of the battery block 21.

[0172] On the other hand, the battery control device 40 and the battery monitoring device 30 communicate wirelessly using the space provided on the right side of the battery block 21 as a radio wave propagation path. This allows the radio wave propagation path and the gas exhaust path to be separated, preventing interference with wireless communication.

[0173] The battery control device 40 and the battery monitoring device 30 are disposed to the side of the battery block 21. This prevents gas from being injected directly from the cell explosion-proof valve 22a onto the battery monitoring device 30 or the battery control device 40. This prevents the battery monitoring device 30 or the battery control device 40 from being damaged by gas.

[0174] Due to its structure, the area on the top surface of the housing 50 where the housing explosion-proof valve 51 is provided is thinner than other parts of the housing 50, such as the side surfaces, making it easier for external electromagnetic noise to penetrate. For this reason, the battery monitoring device 30 and the battery control device 40 are provided in a position different from the position where the housing explosion-proof valve 51 is provided, i.e., in a position that does not overlap with the area of ​​the housing explosion-proof valve 51 in the vertical direction (Z direction). This makes it possible to suppress the effects of external noise.

[0175] Furthermore, the space provided to the right of battery block 21 is located in a different position from the position where housing explosion-proof valve 51 is provided, i.e., in a position that does not overlap in the vertical direction (Z direction) with the area of ​​housing explosion-proof valve 51. When wireless communication is performed using the space provided to the right of battery block 21 as a radio wave propagation path, the effects of electromagnetic noise entering through housing explosion-proof valve 51 can be suppressed.

[0176] Furthermore, the housing explosion-proof valve 51 faces the top surface of the battery cell 22, and the battery monitoring device 30 and battery control device 40 are not disposed between the housing explosion-proof valve 51 and the battery cell 22. Therefore, electromagnetic noise that enters from the outside through the housing explosion-proof valve 51 is reflected by the battery cell 22 (its battery case) and is likely to be released to the outside again through the housing explosion-proof valve 51. In other words, the battery cell 22 blocks the path of electromagnetic noise that enters from the outside through the housing explosion-proof valve 51, thereby suppressing the impact on wireless communication.

[0177] (Modification of Third Embodiment) Hereinafter, a modification of the third embodiment in which the configuration of the battery pack 11 is partially changed will be described.

[0178] In the above embodiment and modified examples, the cell explosion-proof valve 22a may be provided on a side surface of the battery cell 22. That is, it may be provided on either the side surface in the X direction or the side surface in the Y direction. In this case, the battery monitoring device 30 and the battery control device 40 may be disposed so as to face the side surface on which the cell explosion-proof valve 22a is not provided. Alternatively, the battery monitoring device 30 and the battery control device 40 may be disposed on the top surface of the battery cell 22.

[0179] For example, as shown in FIG. 31( a), a case will be described in which battery cells 22 are arranged in the X direction and a cell explosion-proof valve 22a is provided on one side surface of each battery cell 22 in the Y direction (the side surface facing the page in FIG. 31( a)). In this case, as shown in FIG. 31( a), the battery monitoring device 30 may be disposed on the top surface of the battery cell 22, and the battery control device 40 may be disposed adjacent to the side surface of the battery cell 22 in the X direction. In other words, the battery monitoring device 30 and the battery control device 40 do not need to be disposed in a position facing the cell explosion-proof valve 22a. Furthermore, although not shown, the battery monitoring device 30 and the battery control device 40 may also be disposed on the opposite side surface of the battery cell 22 in the Y direction (the side surface not provided with the cell explosion-proof valve 22a).

[0180] In the above embodiment and modified examples, it is preferable that the housing explosion-proof valve 51 is provided on a surface opposite to the surface on which the cell explosion-proof valve 22 a is disposed. More preferably, it is preferable that the housing explosion-proof valve 51 is provided at a position opposite to the cell explosion-proof valve 22 a. In this case, it is preferable that there is nothing obstructing the passage between the cell explosion-proof valve 22 a and the housing explosion-proof valve 51.

[0181] For example, as shown in Figure 31 (a), if a cell explosion-proof valve 22a is provided on the side of each battery cell 22, a housing explosion-proof valve 51 (shown by a dashed line) may be provided on the side wall of the storage case 50 opposite the cell explosion-proof valve 22a.

[0182] As shown in FIG. 31( b ), when the interior of the battery pack 11 is viewed from above, the gap between the right side surface of each battery cell 22 and the right sidewall 50b of the casing 50 may serve as a gas exhaust passage 301. This gas exhaust passage 301 is formed to extend in the X direction. A housing explosion-proof valve 51 may be provided on the sidewall 50a of the casing 50 where this gas exhaust passage 301 abuts in the X direction. In this way, gas exhausted from the right side surface of the battery cell 22 passes through the gas exhaust passage 301 and is exhausted to the outside from the housing explosion-proof valve 51 provided on the sidewall 50a of the casing 50 in the X direction. Furthermore, if the housing explosion-proof valve 51 is provided on the sidewall 50a opposite the battery control device 40 in the X direction, it is possible to prevent gas from filling the area around the battery control device 40.

[0183] In the above embodiment and modified examples, the battery monitoring device 30 and the battery control device 40 may be arranged so as to face the surface on which the cell explosion-proof valve 22 a is provided. In this case, the battery monitoring device 30 and the battery control device 40 are arranged at different positions so as not to face the cell explosion-proof valve 22 a.

[0184] Here, a specific description will be given with reference to Figure 32. In Figure 32, multiple battery blocks 21 are arranged in the X direction. In each battery block 21, multiple battery cells 22 are arranged in the Y direction, and a cell explosion-proof valve 22a is provided on the top surface of each battery cell 22 on one side in the X direction (the right side in Figure 32).

[0185] The battery monitoring device 30 is disposed on the other side in the X direction (left side in FIG. 32 ) on the top surface of the battery cell 22. That is, the battery monitoring device 30 is disposed on the top surface of the battery cell 22 at a different position from the cell explosion-proof valve 22a (a position that does not face the cell explosion-proof valve 22a and does not overlap in the Z direction (up and down direction)). As shown in FIG. 32 , the battery monitoring device 30 may be disposed across multiple battery cells 22. Also, in FIG. 32 , the battery control device 40 is disposed to the side of the battery block 21 in the Y direction. This prevents gas from being directly injected into the battery monitoring device 30 or the battery control device 40 even if gas is discharged from the cell explosion-proof valve 22a.

[0186] Furthermore, the housing explosion-proof valves 51 of the casing 50 are provided on the top surface of the casing 50, approximately directly above each cell explosion-proof valve 22a (not shown). This allows gas to be discharged above the battery cells 22, preventing the gas from crossing the radio wave propagation path and becoming an obstacle. An example of the radio wave propagation path is shown by the dashed line in Figure 32.

[0187] In the above embodiment and modified examples, the cell explosion-proof valve 22a and the housing explosion-proof valve 51 may each be provided on the underside (Z-direction surface) of the casing 50. In this case, the battery monitoring device 30 and the battery control device 40 may be provided above or to the side of the battery block 21, i.e., somewhere other than below the battery block 21. This allows the radio wave propagation path and the gas exhaust path to be separated. It also prevents gas from being injected directly from the cell explosion-proof valve 22a onto the battery monitoring device 30 and the battery control device 40.

[0188] In the above embodiment and modified examples, a smoke exhaust duct may be provided to guide gas discharged from the cell explosion-proof valve 22a of the battery cell 22 to the housing explosion-proof valve 51 of the accommodating case 50. It is desirable to provide this smoke exhaust duct so as not to interfere with (cross) the propagation path of radio waves.

[0189] A specific description will now be given with reference to Figure 33. In the modified example of Figure 33, multiple battery blocks 21 are aligned in the X direction. In each battery block 21, multiple battery cells 22 are aligned in the Y direction, and a cell explosion-proof valve 22a is provided on one side in the X direction (the right side in Figure 33) of the top surface of each battery cell 22. In Figure 33, the cell explosion-proof valve 22a is indicated by a dashed line.

[0190] The battery monitoring device 30 is disposed on the other side in the X direction (the left side in FIG. 33 ) on the top surface of the battery cell 22. That is, the battery monitoring device 30 is provided in a different position from the cell explosion-proof valve 22a on the top surface of the battery cell 22 (a position that does not face the cell explosion-proof valve 22a and does not overlap with it in the Z direction). Also, in FIG. 33 , the battery control device 40 is disposed to the side of the battery block 21 in the Y direction.

[0191] The smoke exhaust duct 350 is configured in a cylindrical shape that extends linearly in the Y direction and is positioned directly above each cell explosion-proof valve 22a in the vertical direction. The smoke exhaust duct 350 is generally made of metal. A smoke exhaust duct 350 is provided for each battery block 21, and extends across the cell explosion-proof valves 22a of the multiple battery cells 22 that make up the battery block 21. In the modified example shown in Figure 32, the smoke exhaust duct 350 is provided to cover the cell explosion-proof valves 22a of all of the battery cells 22 that make up the battery block 21.

[0192] The smoke exhaust duct 350 has a through-hole at a location corresponding to the cell explosion-proof valve 22a. When the cell explosion-proof valve 22a is open, the interior of the battery cell 22 communicates with the smoke exhaust duct 350 via the through-hole. Therefore, gas discharged from the cell explosion-proof valve 22a is discharged into the smoke exhaust duct 350. The smoke exhaust duct 350 is formed to extend toward the housing explosion-proof valve 51 provided on the side wall 50b of the housing case 50 and opens at a position corresponding to the housing explosion-proof valve 51. In other words, in the Y direction, the end of the smoke exhaust duct 350 on the housing explosion-proof valve 51 side is open and connected to the housing explosion-proof valve 51. Therefore, gas passing through the smoke exhaust duct 350 is discharged to the outside via the housing explosion-proof valve 51. Note that the end of the smoke exhaust duct 350 opposite the housing explosion-proof valve 51 in the Y direction is closed.

[0193] Meanwhile, the battery monitoring device 30 is disposed on the other side in the X direction (the left side in FIG. 33 ) on the top surface of the battery cell 22. In other words, the battery monitoring device 30 is disposed in a position on the top surface of the battery cell 22 that does not interfere with the smoke exhaust duct 350. Also, in FIG. 33 , the battery control device 40 is disposed on the side of the battery block 21 in the Y direction, on the opposite side from the housing explosion-proof valve 51. This prevents gas from being directly injected into the battery monitoring device 30 or the battery control device 40, even if gas is discharged from the cell explosion-proof valve 22 a.

[0194] The propagation path of radio waves between the battery control device 40 and the battery monitoring device 30 is set so as not to intersect with the smoke exhaust duct 350. For example, the propagation path indicated by the dashed arrow in Figure 33 runs parallel to the smoke exhaust duct 350. This prevents gas from interfering with the propagation path, allowing for optimal wireless communication.

[0195] The smoke exhaust duct 350 extends to the housing explosion-proof valve 51 provided on the side wall 50b of the housing case 50. The smoke exhaust duct 350 is made of metal. Therefore, even if the housing explosion-proof valve 51 is opened, making it easier for external electromagnetic noise to enter, the metal smoke exhaust duct 350 covers the housing explosion-proof valve 51, preventing leakage outside the smoke exhaust duct 350. In other words, the smoke exhaust duct 350 can function as an electromagnetic wave shield that blocks electromagnetic wave noise from entering through the housing explosion-proof valve 51. This prevents external electromagnetic noise from affecting the battery control device 40, battery monitoring device 30, and other devices located outside the smoke exhaust duct 350.

[0196] In the above-described embodiment and modified examples, the battery cells 22 may be formed of long, plate-shaped blade cells. In this case, for example, as shown in FIG. 34 , a battery block 421 is formed by stacking multiple blade cells 401 in a predetermined direction (the Z direction (vertical direction) in FIG. 34 ). The blade cell 401 in FIG. 34 has a positive electrode terminal 404a at one longitudinal end and a negative electrode terminal 404b at the other end. Therefore, the battery monitoring device 30 is disposed in the longitudinal center of the blade cell 401, and the positive detection wire 402 and the negative detection wire 403 extend from the longitudinal center to both longitudinal sides and are connected to the respective electrode terminals 404a and 404b. This allows the wiring resistance of the positive detection wire 402 connected to the positive side and the wiring resistance of the negative detection wire 403 connected to the negative side to be the same, preventing deterioration of detection accuracy.

[0197] 34 , the battery monitoring device 30, positive electrode detection line 402, and negative electrode detection line 403 are provided on the top surface of a battery block 421. The positive electrode detection line 402 and negative electrode detection line 403 are provided in the middle in the width direction (direction perpendicular to the longitudinal direction) of the battery block 421. Meanwhile, the battery monitoring device 30 is positioned offset from the positive electrode detection line 402 and negative electrode detection line 403 in the width direction.

[0198] The wireless circuit 410 (shown by a dashed line) included in the battery monitoring device 30 is provided on the monitoring circuit board 34 on the opposite side in the width direction to the connection positions of the positive detection line 402 and the negative detection line 403. In other words, the wireless circuit 410 is disposed in a position as far away as possible from the noisy positive detection line 402 and the negative detection line 403. The wireless circuit 410 refers to circuit elements related to wireless communication, and includes the slave device side wireless antenna 33, the slave device side wireless IC 32, and a front-end circuit.

[0199] 34, the explosion-proof valve 401a of the blade cell 401 is provided on the longitudinal end face. This prevents gas from being directly injected from the explosion-proof valve 401a onto the battery monitoring device 30 located on the top surface of the battery block 421. This also prevents gas from entering the radio wave propagation path.

[0200] In the third embodiment, it is not necessary to provide the metal plates 37, 47, which are proximate conductors that are electrostatically coupled to the antennas 33, 43. Furthermore, in the third embodiment, it is not necessary to provide an electromagnetic wave blocking member, such as the electromagnetic wave shield 201, that blocks electromagnetic noise from a noise source disposed in the battery accommodating space.

[0201] The above-described embodiments and their modifications can be combined within the scope of possible combinations.

[0202] For example, in the battery monitoring device 30 or battery control device 40 described in the second embodiment (and its variations, the same applies below) or the third embodiment (and its variations, the same applies below), the internal structure of the battery monitoring device 30 or battery control device 40 of the first embodiment (and its variations), specifically the structure of the antennas 33, 43 and metal plates 37, 47, may be adopted.

[0203] Furthermore, the configurations and arrangements of the housing explosion-proof valve 51 and the cell explosion-proof valve 22a described in the third embodiment may be appropriately adopted in the storage case 50 and battery cell 22 of the first embodiment (and its variations, the same applies below) and the second embodiment. For example, in the first and second embodiments, a configuration can naturally be derived in which the cell explosion-proof valve 22a is provided on the top surface or side surface of the battery cell 22, and the housing explosion-proof valve 51 is provided on the top surface (center of the top surface) or side surface of the storage case 50, as in the third embodiment.

[0204] Furthermore, in the first and second embodiments, similar to the third embodiment, the housing explosion-proof valve 51 and the cell explosion-proof valve 22a may be arranged so as to avoid the propagation path of radio waves between the battery monitoring device 30 and the battery control device 40. Furthermore, in the first and second embodiments, similar to the third embodiment, the battery monitoring device 30 (or the battery control device 40) may be arranged so as to avoid the housing explosion-proof valve 51 and the cell explosion-proof valve 22a.

[0205] Furthermore, in the first and second embodiments, similar to the third embodiment, configurations for suppressing the impact of exhaust gas on wireless communication, such as a gas exhaust passage 301 and a smoke exhaust duct 350, may be adopted.

[0206] In addition, all of the first, second and third embodiments may be combined.

[0207] The following describes characteristic configurations extracted from the above-described embodiments.

[0208] [Configuration 1] A wireless device (30, 40) of a battery monitoring system (100) comprising: a wireless antenna (33, 43); and a proximate conductor (37, 47) that overlaps with at least a portion of the projection surface of the wireless antenna when a predetermined direction is the projection direction.

[0209] [Configuration 2] The wireless device according to Configuration 1, further comprising a circuit board (34, 44) on which the wireless antenna is mounted, wherein the proximity conductor is disposed closest to the wireless antenna compared to other conductors other than conductors mounted on the circuit board.

[0210] [Configuration 3] The wireless device according to configuration 2, wherein the predetermined direction is a vertical direction of the circuit board.

[0211] [Configuration 4] The wireless device according to any one of configurations 1 to 3, wherein the projection surface of the wireless antenna in the predetermined direction is a surface that is largest compared to the projection surface in other directions.

[0212] [Configuration 5] The wireless device according to any one of configurations 2 to 4, wherein the proximity conductor is flat and disposed with its plane parallel to the circuit board.

[0213] [Configuration 6] The wireless device according to Configuration 2 or 3, wherein the wireless antenna comprises an element (33 a, 43 a) for radiating radio waves and a wiring pattern (33 b, 43 b) arranged opposite to the element, the wiring pattern having a potential corresponding to a reference potential of the circuit board, and the proximity conductor is arranged on the side of the circuit board opposite to the surface on which the element is arranged.

[0214] [Configuration 7] The wireless device according to Configuration 6, further comprising: a wireless IC (32, 42) connected to the wireless antenna; the wireless IC being arranged on a surface of the circuit board opposite to a surface on which the element is arranged; and the proximity conductor being configured to cover the wireless IC.

[0215] [Configuration 8] The wireless device according to any one of configurations 1 to 7, wherein the entire projection surface of the wireless antenna overlaps with the adjacent conductor in the predetermined direction.

[0216] [Configuration 9] The wireless device according to any one of configurations 1 to 8, wherein the proximity conductor forms part of the housing of the wireless device.

[0217] [Configuration 10] The wireless device according to any one of configurations 1 to 9, wherein the housing of the wireless device is provided with a passage portion that allows radio waves from the wireless antenna to pass through.

[0218] [Configuration 11] The wireless device according to configuration 10, wherein the passing portion is provided closer to the communication partner than the wireless antenna and on the opposite side of the wireless antenna from the proximate conductor.

[0219] [Configuration 12] The wireless device according to configuration 10 or 11, wherein the width of the passing portion in a direction perpendicular to the predetermined direction is equal to or greater than half the wavelength of the radio wave radiated from the wireless antenna.

[0220] [Configuration 13] The wireless device according to any one of Configurations 10 to 12, wherein in the predetermined direction, no conductor is arranged on the opposite side of the proximate conductor with respect to the wireless antenna, or, if a conductor is arranged, the distance between the conductor and the wireless antenna is equal to or greater than half the wavelength of the radio wave radiated from the wireless antenna.

[0221] [Configuration 14] The wireless device according to Configuration 13, wherein the distance between the housing of the wireless device and the wireless antenna in the predetermined direction is equal to or greater than half the wavelength of the radio wave radiated from the wireless antenna.

[0222] [Configuration 15] The wireless device according to any one of configurations 1 to 14, wherein the wireless antenna comprises an element (33a, 43a) for radiating radio waves and a wiring pattern (33b, 43b) arranged opposite the element, the wiring pattern having a potential corresponding to a reference potential of a circuit board on which the wireless antenna is mounted, the wiring pattern having a comb-tooth shape or a meandering shape, and the projection surface of the wireless antenna includes at least the projection surface of the element and the projection surface of the wiring pattern.

[0223] [Configuration 16] The wireless device according to any one of configurations 1 to 15, wherein the wireless antenna comprises an element (33a, 43a) for radiating radio waves and a wiring pattern (33b, 43b) arranged opposite the element, the wiring pattern having a potential corresponding to a reference potential of a circuit board on which the wireless antenna is mounted, the element having at least one of a comb shape, an L-shape, and a stub shape, and the projection surface of the wireless antenna includes at least the projection surface of the element and the projection surface of the wiring pattern.

[0224] [Configuration 17] The wireless device according to any one of configurations 1 to 16, further comprising an insulating sheet (36, 46) between the wireless antenna and the proximate conductor.

[0225] [Configuration 18] The wireless device according to any one of configurations 1 to 7, wherein the capacitance generated between the nearby conductor and the wireless antenna is larger than the capacitance generated between another conductor and the wireless antenna.

[0226] [Configuration 19] A power supply unit (11) having a plurality of wireless devices (30, 40) according to any one of configurations 1 to 18 and a battery section (20, 21, 22), for transmitting and receiving battery information between the wireless devices by wireless communication, further comprising a noise source (60) that generates electromagnetic noise, wherein the plurality of wireless devices and the noise source are both disposed within a battery accommodating space of the power supply unit, and an electromagnetic wave blocking member (201) is interposed between the wireless devices and the noise source.

[0227] [Configuration 20] The power supply unit according to Configuration 19, wherein the housing (35, 45) of the wireless device is provided with a passageway that allows radio waves to pass through, and the passageway is located on the communication partner side of the wireless antenna (33, 43) of the wireless device in the radio wave propagation path, and on the opposite side of the noise source with respect to the wireless antenna.

[0228] [Configuration 21] The power supply unit according to Configuration 19 or 20, wherein, of the surfaces constituting the housing of the wireless device, the surface on the noise source side is made of the electromagnetic wave blocking member.

[0229] [Configuration 22] The power supply unit according to any one of Configurations 19 to 21, wherein the wireless device has an antenna that emits directional radio waves, and the antenna is oriented so that the direction in which the radio waves emitted from the antenna are strong is toward a communication partner but not toward the noise source.

[0230] [Configuration 23] The power supply unit according to Configuration 22, wherein the antenna is oriented so that a direction in which a strong radio wave is radiated from the antenna is not directed toward the electromagnetic wave blocking member.

[0231] [Configuration 24] The power supply unit according to Configuration 22 or 23, wherein the housing of the wireless device is positioned adjacent to one of the battery cells that make up the battery section, or adjacent to a side wall that separates the battery accommodating space, and the direction of the antenna is determined so that the direction in which the radio waves emitted from the antenna are strong is not directed toward the battery cell or the side wall.

[0232] [Configuration 25] A power supply unit according to any of configurations 19 to 24, wherein the battery section is composed of a plurality of battery cells (22), the noise source is a junction box (60) having one or more relay switches (61) for switching between energizing and de-energizing the battery section, the wireless device includes a battery monitoring device (30) provided for each of the one or more battery cells and for acquiring and transmitting battery information, and a battery control device (40) for receiving the battery information from the battery monitoring device, the battery control device is located closer to the junction box than the battery monitoring device and acquires the total voltage of the battery section from the junction box, and the electromagnetic wave blocking member is provided between the battery control device and the junction box.

[0233] [Configuration 26] The power supply unit according to Configuration 25, wherein the battery control device is disposed above the junction box in the battery accommodating space, and communication is performed by reflecting radio waves off a ceiling surface of the battery accommodating space.

[0234] [Configuration 27] The power supply unit according to any one of Configurations 19 to 26, further comprising a case that houses the battery unit and the wireless device, the noise source being fixed to the outside of the case, and a fixing surface of the noise source that constitutes the case being the electromagnetic wave blocking member.

[0235] [Configuration 28] A power supply unit (11) having a plurality of wireless devices (30, 40) according to any one of configurations 1 to 18 and a battery unit (20, 21, 22), which transmits and receives battery information between the wireless devices by wireless communication, wherein the battery unit is provided with an explosion-proof valve (22a), and the explosion-proof valve is positioned to avoid a propagation path of radio waves emitted from the wireless devices.

[0236] [Configuration 29] The power supply unit according to Configuration 28, wherein the wireless device is arranged so as not to face the explosion-proof valve.

[0237] [Configuration 30] The power supply unit according to Configuration 28 or 29, wherein the explosion-proof valve is provided on one of the side, top, or bottom surfaces of the battery unit, and the wireless device is disposed facing a surface other than the installation surface of the explosion-proof valve.

[0238] [Configuration 31] The power supply unit according to any one of Configurations 28 to 30, further comprising a housing case (50) that houses the wireless device and the battery unit, the housing case having an opening (51) that opens due to internal pressure of the housing case, and the opening is disposed opposite the explosion-proof valve.

[0239] [Configuration 32] The power supply unit according to Configuration 31, wherein the opening of the accommodating case is provided on an upper surface thereof, and the wireless device is positioned so as to avoid being between the battery unit and the upper surface of the accommodating case.

[0240] [Configuration 33] A power supply unit according to any of Configurations 28 to 32, comprising a storage case (50) that stores the wireless device and the battery unit, the storage case having an opening (51) that opens due to internal pressure of the storage case, the opening being positioned so as not to face the explosion-proof valve, and a smoke exhaust path through which gas discharged from the explosion-proof valve passes before reaching the opening is predetermined, and the wireless device is positioned to avoid the smoke exhaust path.

[0241] [Configuration 34] The power supply unit according to Configuration 33, wherein the explosion-proof valve is provided on the side of the battery unit, the opening is provided in a side wall of the storage case, the smoke exhaust path is formed between the side of the battery unit and the side wall of the storage case, the wireless device is disposed above the battery unit, and the propagation path is above the battery unit.

[0242] [Configuration 35] The power supply unit according to Configuration 33 or 34, wherein the battery unit is disposed opposite the opening, and the wireless device and the propagation path are not provided between the opening and the battery unit.

[0243] [Configuration 36] The power supply unit according to any one of Configurations 28 to 35, further comprising a smoke exhaust duct (350) through which gas discharged from the explosion-proof valve passes, and the wireless device is disposed at a position different from the smoke exhaust duct.

[0244] [Configuration 37] The power supply unit of Configuration 36, wherein the smoke exhaust duct is disposed parallel to the propagation path.

[0245] [Configuration 38] The power supply unit according to Configuration 36 or 37, wherein when the explosion-proof valve is open, the opening of the explosion-proof valve communicates with the interior of the smoke exhaust duct.

[0246] [Configuration 39] A power supply unit according to any one of Configurations 36 to 38, comprising a housing case (50) that houses the wireless device and the battery unit, the housing case having an opening (51) that opens due to internal pressure of the housing case, the smoke exhaust duct being a metal tube, and the opening and an end of the smoke exhaust duct being connected so that the opening and the inside of the smoke exhaust duct are in communication.

[0247] [Configuration 201] A power supply unit (11) having a battery section (20, 21, 22), comprising: a plurality of wireless devices (30, 40) that transmit and receive battery information by wireless communication; and a noise source (60) that generates electromagnetic noise, wherein the plurality of wireless devices and the noise source are both arranged within a battery storage space of the power supply unit, and an electromagnetic wave blocking member (201) is interposed between the wireless devices and the noise source.

[0248] [Configuration 202] A power supply unit according to configuration 201, wherein the housing (35, 45) of the wireless device is provided with a passageway for passing radio waves, and the passageway is located on the communication partner side of the wireless antenna (33, 43) of the wireless device in the radio wave propagation path, and on the opposite side of the noise source relative to the wireless antenna.

[0249] [Configuration 203] The power supply unit according to Configuration 201 or 202, wherein, of the surfaces constituting the housing of the wireless device, the surface on the noise source side is made of the electromagnetic wave blocking member.

[0250] [Configuration 204] The power supply unit according to any one of Configurations 201 to 203, wherein the wireless device has an antenna that emits directional radio waves, and the antenna is positioned so that the direction in which the radio waves emitted from the antenna are strong is toward a communication partner but not toward the noise source.

[0251] [Configuration 205] The power supply unit according to Configuration 204, wherein the antenna is oriented so that a direction in which a strong radio wave is radiated from the antenna is not directed toward the electromagnetic wave blocking member.

[0252] [Configuration 206] A power supply unit according to configuration 204 or 205, wherein the housing of the wireless device is positioned adjacent to one of the battery cells that constitute the battery section, or adjacent to a side wall that separates the battery accommodating space, and the direction of the antenna is determined so that the direction of the strong radio waves radiated from the antenna is not directed toward the battery cell or the side wall.

[0253] [Configuration 207] A power supply unit according to any one of configurations 201 to 206, wherein the battery section is composed of a plurality of battery cells (22), the noise source is a junction box (60) having one or more relay switches (61) for switching between energizing and de-energizing the battery section, the wireless device includes a battery monitoring device (30) provided for each of one or more battery cells, which acquires and transmits battery information, and a battery control device (40) which receives the battery information from the battery monitoring device, the battery control device is located closer to the junction box than the battery monitoring device, and acquires the total voltage of the battery section from the junction box, and the electromagnetic wave blocking member is provided between the battery control device and the junction box.

[0254] [Configuration 208] The power supply unit according to Configuration 207, wherein the battery control device is disposed above the junction box in the battery accommodating space, and communication is performed by reflecting radio waves off a ceiling surface of the battery accommodating space.

[0255] [Configuration 209] The power supply unit according to Configuration 201, further comprising a case that houses the battery unit and the wireless device, the noise source being fixed to the outside of the case, and the fixing surface of the noise source that constitutes the case being the electromagnetic wave blocking member.

[0256] [Configuration 301] A power supply unit (11) having a battery section (22), comprising: a plurality of wireless devices (30, 40) that transmit and receive battery information by wireless communication; the battery section is provided with an explosion-proof valve (22a); and the explosion-proof valve is positioned to avoid the propagation path of radio waves emitted from the wireless devices.

[0257] [Configuration 302] The power supply unit according to Configuration 301, wherein the wireless device is arranged so as not to face the explosion-proof valve. [Configuration 303] The power supply unit according to Configuration 301 or 302, wherein the explosion-proof valve is provided on one of the side, top, or bottom of the battery unit, and the wireless device is arranged to face a surface other than the installation surface of the explosion-proof valve.

[0258] [Configuration 304] The power supply unit according to any one of configurations 301 to 303, further comprising a housing case (50) for housing the wireless device and the battery unit, the housing case having an opening (51) that opens due to internal pressure of the housing case, and the opening is disposed opposite the explosion-proof valve.

[0259] [Configuration 305] The power supply unit according to Configuration 304, wherein the opening of the accommodating case is provided on the top surface thereof, and the wireless device is positioned so as to avoid being between the battery unit and the top surface of the accommodating case.

[0260] [Configuration 306] A power supply unit according to any of configurations 301 to 305, comprising a storage case (50) that stores the wireless device and the battery unit, the storage case having an opening (51) that opens due to internal pressure of the storage case, the opening being positioned not facing the explosion-proof valve, and a smoke exhaust path through which gas discharged from the explosion-proof valve passes before reaching the opening is predetermined, and the wireless device is positioned to avoid the smoke exhaust path.

[0261] [Configuration 307] The power supply unit described in Configuration 306, wherein the explosion-proof valve is provided on the side of the battery unit, the opening is provided on the side wall of the storage case, the smoke exhaust path is formed between the side of the battery unit and the side wall of the storage case, the wireless device is disposed above the battery unit, and the propagation path is above the battery unit.

[0262] [Configuration 308] The power supply unit according to any one of configurations 304 to 307, wherein the battery unit is disposed opposite the opening, and the wireless device and the propagation path are not provided between the opening and the battery unit.

[0263] [Configuration 309] The power supply unit according to any one of configurations 301 to 308, further comprising a smoke exhaust duct (350) through which gas discharged from the explosion-proof valve passes, and the wireless device is disposed at a position different from the smoke exhaust duct.

[0264] [Configuration 310] The power supply unit of Configuration 309, wherein the smoke exhaust duct is positioned parallel to the propagation path.

[0265] [Configuration 311] The power supply unit according to configuration 309 or 310, wherein when the explosion-proof valve is open, the port of the explosion-proof valve communicates with the interior of the smoke exhaust duct.

[0266] [Configuration 312] A power supply unit according to any one of configurations 309 to 311, comprising a housing case (50) that houses the wireless device and the battery unit, the housing case having an opening (51) that opens due to internal pressure of the housing case, the smoke exhaust duct being a metal tube, and the opening and an end of the smoke exhaust duct being connected so that the opening and the inside of the smoke exhaust duct are in communication.

[0267] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A wireless device (30, 40) of a battery monitoring system (100) comprising: a wireless antenna (33, 43); and a nearby conductor (37, 47) that overlaps with at least a portion of the projection surface of the wireless antenna when a predetermined direction is the projection direction.

2. The wireless device according to claim 1, further comprising a circuit board (34, 44) on which the wireless antenna is mounted, and the proximate conductor is disposed closest to the wireless antenna compared to other conductors other than the conductors mounted on the circuit board.

3. The wireless device according to claim 2, wherein the predetermined direction is a vertical direction of the circuit board.

4. The wireless device according to claim 3, wherein the projection surface of the wireless antenna in the predetermined direction is the largest compared to the projection surface in other directions.

5. The wireless device according to claim 2, wherein the proximity conductor is flat and disposed with its flat surface facing the circuit board.

6. A wireless device as described in claim 2, wherein the wireless antenna comprises an element (33a, 43a) for radiating radio waves and a wiring pattern (33b, 43b) arranged opposite the element, the wiring pattern having a potential corresponding to a reference potential of the circuit board, and the adjacent conductor is arranged on the side of the circuit board opposite to the surface on which the element is arranged.

7. The wireless device according to claim 6, further comprising a wireless IC (32, 42) connected to the wireless antenna, the wireless IC being arranged on a surface of the circuit board opposite to a surface on which the elements are arranged, and the proximity conductor being configured to cover the wireless IC.

8. A wireless device according to any one of claims 1 to 7, wherein the entire projection surface of the wireless antenna overlaps with the adjacent conductor in the specified direction.

9. A radio device according to any one of claims 1 to 7, wherein the proximate conductor constitutes a part of the housing of the radio device.

10. A wireless device according to any one of claims 1 to 7, wherein the housing of the wireless device is provided with a passage portion that allows radio waves from the wireless antenna to pass therethrough.

11. The wireless device according to claim 10, wherein the passing section is provided on the communication partner side of the wireless antenna and on the opposite side of the wireless antenna to the proximate conductor.

12. The wireless device according to claim 11, wherein the width dimension of said passage portion is equal to or greater than 1 / 2 the wavelength of the radio wave radiated from said wireless antenna.

13. A radio device as described in claim 11, wherein in the specified direction, no conductor is arranged on the opposite side of the proximate conductor with respect to the radio antenna, or, if a conductor is arranged, the distance between the conductor and the radio antenna is equal to or greater than half the wavelength of the radio waves radiated from the radio antenna.

14. The wireless device according to claim 13, wherein the distance between the housing of the wireless device and the wireless antenna in the predetermined direction is equal to or greater than 1 / 2 the wavelength of the radio wave radiated from the wireless antenna.

15. A wireless device as claimed in any one of claims 1 to 7, wherein the wireless antenna comprises an element (33a, 43a) for radiating radio waves and a wiring pattern (33b, 43b) arranged opposite the element, the wiring pattern having a potential corresponding to a reference potential of a circuit board on which the wireless antenna is mounted, the wiring pattern having a comb-tooth shape or a meandering shape, and the projection surface of the wireless antenna includes at least the projection surface of the element and the projection surface of the wiring pattern.

16. A wireless device as claimed in any one of claims 1 to 7, wherein the wireless antenna comprises an element (33a, 43a) for radiating radio waves and a wiring pattern (33b, 43b) arranged opposite the element, the wiring pattern having a potential corresponding to a reference potential of a circuit board on which the wireless antenna is mounted, the element having at least one of a comb shape, an L-shape and a stub shape, and the projection surface of the wireless antenna includes at least the projection surface of the element and the projection surface of the wiring pattern.

17. A radio device according to any one of claims 1 to 7, further comprising an insulating sheet (36, 46) between the radio antenna and the adjacent conductor.

18. A wireless device according to any one of claims 1 to 7, wherein the capacitance generated between the adjacent conductor and the wireless antenna is larger than the capacitance generated between other conductors and the wireless antenna.

19. A power supply unit (11) having a plurality of wireless devices (30, 40) as set forth in any one of claims 1 to 7 and a battery section (20, 21, 22), which transmits and receives battery information between the wireless devices via wireless communication, further comprising a noise source (60) that generates electromagnetic noise, wherein the wireless devices and the noise source are both disposed within the battery storage space of the power supply unit, and an electromagnetic wave blocking member (201) is interposed between the wireless devices and the noise source.

20. A power supply unit as described in claim 19, wherein the housing (35, 45) of the wireless device is provided with a passage section for passing radio waves, and the passage section is positioned on the communication partner side of the wireless device's wireless antenna (33, 43) in the radio wave propagation path, and on the opposite side of the noise source with respect to the wireless antenna.

21. The power supply unit according to claim 19, wherein, of the faces constituting the housing of the wireless device, the face facing the noise source is made of the electromagnetic wave blocking material.

22. The power supply unit of claim 19, wherein the wireless device has an antenna that emits directional radio waves, and the direction of the antenna is determined and positioned so that the direction in which the radio waves emitted from the antenna are strong is toward the communication partner but not toward the noise source.

23. A power supply unit as described in claim 22, wherein the antenna is oriented so that the direction in which the radio waves emitted from the antenna are strong is not directed toward the electromagnetic wave blocking member.

24. A power supply unit as described in claim 22, wherein the housing of the wireless device is positioned adjacent to one of the battery cells constituting the battery section, or adjacent to a side wall dividing the battery storage space, and the direction of the antenna is determined so that the direction in which the radio waves emitted from the antenna are strong is not directed toward the battery cell and the side wall.

25. A power supply unit as described in claim 19, wherein the battery section is composed of a plurality of battery cells (22), the noise source is a junction box (60) having one or more relay switches (61) for switching between energizing and de-energizing the battery section, the wireless device includes a battery monitoring device (30) provided for each of the one or more battery cells for acquiring and transmitting battery information, and a battery control device (40) for receiving the battery information from the battery monitoring device, the battery control device is positioned closer to the junction box than the battery monitoring device and acquires the total voltage of the battery section from the junction box, and the electromagnetic wave blocking member is provided between the battery control device and the junction box.

26. A power supply unit as described in claim 25, wherein the battery control device is disposed above the junction box in the battery accommodating space, and communicates by reflecting radio waves off a ceiling surface of the battery accommodating space.

27. A power supply unit as described in claim 19, comprising a case that houses the battery unit and the wireless device, the noise source being fixed to the outside of the case, and a fixing surface of the noise source that constitutes the case being made to be the electromagnetic wave blocking member.

28. A power supply unit (11) having a plurality of wireless devices (30, 40) as set forth in any one of claims 1 to 7 and a battery section (20, 21, 22) for transmitting and receiving battery information between the wireless devices via wireless communication, wherein the battery section is provided with an explosion-proof valve (22a), and the explosion-proof valve is positioned to avoid the propagation path of radio waves emitted from the wireless devices.

29. The power supply unit according to claim 28, wherein the wireless device is positioned so as to avoid facing the explosion-proof valve.

30. A power supply unit as described in claim 28, wherein the explosion-proof valve is provided on one of the side, top, or bottom surfaces of the battery section, and the wireless device is disposed facing a surface other than the surface on which the explosion-proof valve is installed.

31. A power supply unit as described in claim 28, comprising a storage case (50) for storing the wireless device and the battery unit, the storage case having an opening (51) that opens due to internal pressure of the storage case, the opening being positioned opposite the explosion-proof valve.

32. A power supply unit as described in claim 31, wherein the opening of the storage case is provided on its top surface, and the wireless device is positioned so as to avoid being between the battery section and the top surface of the storage case.

33. A power supply unit as described in claim 28, comprising a storage case (50) for storing the wireless device and the battery unit, the storage case having an opening (51) that opens due to internal pressure of the storage case, the opening being positioned not facing the explosion-proof valve, and a smoke exhaust path through which gas discharged from the explosion-proof valve passes on its way to the opening is predetermined, and the wireless device is positioned to avoid the smoke exhaust path.

34. A power supply unit as described in claim 33, wherein the explosion-proof valve is provided on the side of the battery unit, the opening is provided in a side wall of the storage case, the smoke exhaust path is formed between the side of the battery unit and the side wall of the storage case, the wireless device is disposed above the battery unit, and the propagation path is above the battery unit.

35. A power supply unit as set forth in claim 33, wherein the battery section is disposed opposite the opening, and the wireless device and the propagation path are not provided between the opening and the battery section.

36. The power supply unit according to claim 28, further comprising a smoke exhaust duct (350) through which gas discharged from the explosion-proof valve passes, and the wireless device is disposed at a position different from the smoke exhaust duct.

37. A power supply unit as claimed in claim 36, wherein the smoke exhaust duct is arranged parallel to the propagation path.

38. The power supply unit according to claim 36, wherein when the explosion-proof valve is open, the port of the explosion-proof valve communicates with the interior of the smoke exhaust duct.

39. A power supply unit as described in claim 36, comprising a housing case (50) for housing the wireless device and the battery unit, the housing case having an opening (51) that opens due to internal pressure of the housing case, and the smoke exhaust duct being a metal tube, the opening being connected to an end of the smoke exhaust duct so that the opening communicates with the inside of the smoke exhaust duct.

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