Battery unit

Abstract

A battery unit (11) comprises: battery sections (20, 21, 22); a slave communication device (30) that detects battery information; a master communication device (40) that controls the slave communication device; and a conductive housing (50) that accommodates the aforementioned components. In the battery unit, the slave communication device is disposed in a slave-side passage (70) surrounded by the inner surface of the housing and the outer surfaces of the battery sections in a first direction. A radio wave of wireless communication transmitted from the master communication device passes through at least the slave-side passage as a propagation path and is received by the slave communication device. When a wavelength of the radio wave used in the wireless communication is denoted by λ, a dimension of the slave-side passage in a second direction orthogonal to the first direction is not less than 1 / 2 × λ and less than 1 × λ.

Description

Battery Unit Cross - reference to Related Applications

[0001] This application is based on Japanese Application No. 2024 - 172478 filed on October 1, 2024, the contents of which are incorporated herein by reference.

[0002] This disclosure relates to a battery unit.

[0003] In recent years, there are vehicle battery packs that house an internal battery monitoring system for transmitting or receiving battery status via wireless communication. In such battery packs, various measures have been taken to suppress communication degradation due to the multipath phenomenon of radio waves reflected by metal materials arranged around the battery pack. Such battery packs are described in, for example, Patent Document 1.

[0004] Japanese Patent Publication No. 2023 - 509931

[0005] However, even if the multipath phenomenon based on external radio waves of the battery pack can be suppressed, inside the battery pack, radio wave interference may occur between the radio waves of wireless communication and their reflected waves, resulting in deterioration of communication quality.

[0006] This disclosure has been made in view of the above circumstances, and its main object is to provide a battery unit capable of suppressing deterioration of communication quality.

[0007] A battery unit for solving the above problems comprises a battery section, a slave communicator for detecting battery information, a master communicator for controlling the slave communicator, and a conductive housing for housing them, wherein the master communicator transmits a request command for battery information to the slave communicator via wireless communication, and the slave communicator, upon receiving the request command, detects the battery information based on the request command and transmits it via wireless communication, wherein one or more of the battery sections are housed inside the housing, the slave communicator is positioned in a slave-side passage surrounded by the inner surface of the housing and the outer surface of the battery section in a first direction, or in a slave-side passage surrounded by the outer surface of one battery section and the outer surface of another battery section, the radio waves of the wireless communication transmitted from the master communicator pass through at least the slave-side passage as a propagation path and are received by the slave communicator, and when the wavelength of the radio waves used in the wireless communication is λ, the dimensions of the slave-side passage in a second direction orthogonal to the first direction are 1 / 2 × λ ​​or more and less than 1 × λ.

[0008] With the above configuration, the position where the received power decreases can be kept constant, and by placing the slave communicator to avoid that position, the deterioration of communication quality can be suppressed.

[0009] The above-mentioned and other purposes, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is a schematic diagram of the vehicle; Figure 2 is a block diagram showing the configuration of the battery unit; Figure 3 is a plan view showing the interior of the battery unit; Figure 4 is a side view showing the interior of the battery unit; Figure 5 is a perspective view showing the slave-side passage; Figure 6 is a diagram showing the relationship between height dimension and cutoff frequency; Figure 7 is a diagram showing the received power intensity; Figure 8 is a diagram showing the received power intensity; Figure 9 is an explanatory diagram of the wavelength inside the tube; Figure 10 is a diagram showing the relationship between the received power intensity and position in the Z direction; Figure 11 is a diagram showing the relationship between the received power intensity and position in the X direction; and Figure 12 shows the configuration of the battery unit of the second embodiment. Figure 13 is a diagram showing the processing flow related to wireless communication, Figure 14 is a diagram showing the received power intensity in a comparative example, Figure 15 is a diagram showing the received power intensity in the second embodiment, Figure 16 is a plan view showing the inside of the battery unit in a modified example, Figure 17 is a side view showing the inside of the battery unit in a modified example, Figure 18 is a plan view showing the inside of the battery unit in a modified example, Figure 19 is a plan view showing the inside of the battery unit in a modified example, Figure 20 is a plan view showing the inside of the battery unit in a modified example, and Figure 21 is a side view showing the inside of the battery unit in a modified example.

[0010] Hereinafter, embodiments of the battery unit in this disclosure will be described in detail with reference to the drawings. In principle, the same or corresponding parts in the drawings will be denoted by the same reference numerals and their descriptions will not be repeated between each embodiment and each modification. The following description will focus on applications to vehicles, but the invention is also applicable to other uses, such as drones and other aircraft, ships, construction machinery, agricultural machinery, etc.

[0011] (First Embodiment) Figure 1 is a schematic diagram showing the configuration of a vehicle 10. The vehicle 10 is an electric vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV). The vehicle 10 comprises a battery unit 11 (shown as "Battery" in Figure 1), a power control unit (hereinafter referred to as "PCU") 12 as a power conversion device, a motor 13 (shown as "MG" in Figure 1) as an electrical load, and a vehicle ECU 14 (shown as "ECU" in Figure 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 unit 11 is mounted in the vehicle 10 as a power source for the vehicle 10. In Figure 1, the battery unit 11 is located, for example, in the front compartment. However, the battery unit 11 may also be located in the rear compartment, under the seats, or under the floor.

[0013] The battery unit 11 includes a battery pack 20 (described later) and is a rechargeable DC voltage source. The battery unit 11 supplies power to the electrical load of the vehicle 10. The battery unit 11 also converts power through the PCU 12 and supplies power to the motor 13. The battery unit 11 is also charged through the PCU 12.

[0014] The PCU 12 performs bidirectional power conversion between the battery unit 11 and the motor 13 according to control signals from the vehicle ECU 14. The PCU 12 is configured to include, for example, an inverter that converts the DC voltage from the battery unit 11 to an AC voltage to drive the motor 13, and a converter that boosts the DC voltage supplied to the inverter to an output voltage higher than that of the battery unit 11.

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

[0016] The vehicle ECU 14 consists of a CPU, ROM, RAM, and input / output ports for inputting and outputting various signals. The CPU loads the program stored in the ROM into the RAM and executes it. The program stored in the ROM contains the processing instructions for 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 unit 11, and controls the PCU 12 to instruct the motor 13 to be driven and the battery unit 11 to be charged and discharged.

[0017] <Battery Unit> The battery unit 11 will now be described in detail. Figure 2 is a block diagram showing the configuration of the battery unit 11. Figure 3 is a cross-sectional view (plan view of the inside of the battery unit 11) of the battery unit 11, which schematically shows the arrangement of the various elements housed inside the battery unit 11 when viewed from above, and Figure 4 is a longitudinal cross-sectional view (side view of the inside of the battery unit 11) of the battery unit 11, which schematically shows the arrangement of the various elements housed inside the battery unit 11 when viewed from the side.

[0018] The battery unit 11 includes a battery pack 20, a battery monitoring system 100, and a housing case 50 (shown by a dashed line) that contains them. The battery monitoring system 100 is a system that monitors and manages the battery status of the battery pack 20 using wireless communication. The battery monitoring system 100 includes a plurality of slave communicators 30 and a master communicator 40, and wireless communication is performed between them.

[0019] <Battery Pack> The battery pack 20 has a plurality of battery blocks 21 (sometimes referred to as a battery stack or battery module). The battery pack 20 is formed by connecting these plurality of battery blocks 21 in series and / or in parallel. Each battery block 21 has a plurality of battery cells 22 (shown by dashed lines in Figure 3). Each battery cell 22 is made up of a lithium-ion secondary battery, a nickel-metal hydride secondary battery, etc. A lithium-ion secondary battery is a secondary battery that uses lithium as a charge carrier, and may include not only general lithium-ion secondary batteries with a liquid electrolyte, but also so-called all-solid-state batteries that use a solid electrolyte. The battery block 21 is formed by connecting these plurality of battery cells 22 in series and / or in parallel via busbars (not shown). Whether or not to provide a battery block 21 is optional, and the battery pack 20 may be formed by connecting a plurality of battery cells 22 in series and / or in parallel. In this embodiment, the battery block 21 corresponds to the battery section.

[0020] <Slave Communicator> The slave communicator 30 will now be described. Note that the configuration of each slave communicator 30 is common to all of them. The slave communicator 30 is also called a satellite battery module (SBM) and is provided for each battery block 21, that is, for each of the multiple battery cells 22. As shown in Figure 2, each slave communicator 30 is equipped with a monitoring IC 31, a slave-side wireless IC 32, a slave-side wireless antenna 33, etc. These are connected by wires. These are mounted on the slave-side circuit board 34 of the slave communicator 30 and housed and fixed in the slave-side case 35 (shown by a dashed line in Figure 2), which serves as the housing for the slave communicator 30.

[0021] The monitoring IC 31, also known as the cell monitoring circuit, acquires (senss) battery information from each battery cell 22 constituting the battery block 21 via physical quantity detection sensors (not shown). Examples of physical quantity detection sensors include voltage sensors, temperature sensors, and current sensors. The battery information includes, for example, voltage information, temperature information, and current information from each battery cell 22. The monitoring target of the slave communication device 30 may be the battery block 21, the entire battery pack 20, or it may be changed as desired.

[0022] When the monitoring IC 31 receives data requesting the acquisition and transmission of battery information, it acquires the battery information in accordance with the data request and transmits monitoring data that includes at least the battery information. The data requesting the acquisition and transmission of battery information corresponds to a battery information request command.

[0023] The slave-side wireless IC 32 includes an RF circuit (not shown), a microcontroller, a front-end circuit, etc., for wirelessly transmitting and receiving data. The slave-side wireless IC 32 has a transmission function that modulates data and oscillates at the frequency of the RF signal. At the same time, the slave-side wireless IC 32 has a reception function that demodulates the received data. RF is an abbreviation for "radio frequency".

[0024] The slave-side wireless IC 32 modulates the monitoring data, including battery information, received from the monitoring IC 31, and transmits it to the master communication device 40 via the slave-side wireless antenna 33. At that time, the slave-side wireless IC 32 adds data necessary for wireless communication, such as communication control information, to the monitoring data including battery information before transmitting it. Data necessary for wireless communication includes, for example, an identifier (ID) and an error detection code.

[0025] Furthermore, the slave-side wireless IC 32 receives data wirelessly transmitted from the master communication device 40 via the slave-side wireless antenna 33 and demodulates it. When the slave-side wireless IC 32 receives data (data request) including, for example, a request to acquire and transmit battery information, it transmits (transfers) it to the monitoring IC 31 via a wired connection. Then, in response to the request, when the slave-side wireless IC 32 receives monitoring data including battery information from the monitoring IC 31, it modulates the response data including the monitoring data and wirelessly transmits it to the master communication device 40 via the slave-side wireless antenna 33.

[0026] The slave-side wireless antenna 33 converts RF signals, which are electrical signals, into radio waves and radiates them into space. The slave-side wireless antenna 33 also receives radio waves propagating through space and converts them into electrical signals.

[0027] In this embodiment, the frequency band of the communication frequency f used in wireless communication, that is, the frequency band of the radio waves radiated from the slave-side wireless antenna 33, is the 2.4 GHz band. More specifically, a communication frequency f of 2402 to 2480 MHz is used for wireless communication.

[0028] <Master Communicator> The master communicator 40 is also called a battery ECU or BMU (Battery Management Unit). The master communicator 40 is configured to communicate wirelessly with each slave communicator 30.

[0029] To explain in more detail, as shown in Figure 2, the master communication device 40 includes a battery control MCU 41, a master-side wireless IC 42, a master-side wireless antenna 43, and the like. These are mounted on the master-side circuit board 44 of the master communication device 40 and housed and fixed in the master-side case 45 (shown as a dashed line in Figure 2), which serves as the housing for the master communication device 40.

[0030] The master-side wireless IC 42 is wired to the battery control MCU 41. The master-side wireless IC 42 is also wired to the master-side wireless antenna 43.

[0031] The battery control MCU41 is composed of a microcontroller (Micro Controller Unit) including a CPU, ROM, RAM, and input / output interfaces. The CPU of the battery control MCU41 loads the program stored in ROM into RAM and executes it. The program stored in ROM contains, for example, code related to battery control.

[0032] As an example of the main processing performed by the battery control MCU 41, the battery control MCU 41 sends data (data request) to the slave communication device 30 requesting the 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 slave communication device 30. For example, the battery control MCU 41 may send 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 send battery information including the calculated SOC and SOH to the vehicle ECU 14. The battery control MCU 41 also controls relay switches, etc., that switch the energization and disconnection states between the battery pack 20 and the PCU 12 and motor 13 based on the monitoring results, etc. The battery control MCU 41 may also send an equalization signal to equalize the voltage of each battery cell 22. In this embodiment, the vehicle ECU 14 issued instructions to the PCU 12 to control the charging and discharging of the battery pack 20, but the battery control MCU 41 may 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.

[0033] The master-side wireless IC 42, like the slave-side wireless IC 32, includes an RF circuit (not shown), a microcontroller, a front-end circuit, etc., for wirelessly transmitting and receiving data. The master-side wireless IC 42, like the slave-side wireless IC 32, has both transmitting and receiving functions.

[0034] The master-side wireless IC 42 demodulates the received monitoring data, including battery information, via the master-side wireless antenna 43, and transmits it to the battery control MCU 41. The master-side wireless IC 42 also modulates the data received from the battery control MCU 41 (such as data requests) with data necessary for wireless communication, such as communication control information, and transmits it to the slave communicator 30 via the master-side wireless antenna 43.

[0035] The master-side wireless antenna 43 has the same configuration and function as the slave-side wireless antenna 33. That is, the master-side wireless antenna 43 converts RF signals, which are electrical signals, into radio waves and radiates them into space, and also receives radio waves propagating in space and converts them into electrical signals.

[0036] Furthermore, as mentioned above, the frequency band of the communication frequency f used in wireless communication, that is, the frequency band of the radio waves radiated from the master-side wireless antenna 43, is the 2.4 GHz band. More specifically, the communication frequency f of 2402 to 2480 MHz is used for wireless communication.

[0037] <Housing Case> The housing case 50 is made of a conductor such as metal. The housing case 50 is formed in the shape of a metal box and is approximately a rectangular parallelepiped. Part of it may be made of a non-conductive material such as resin. The housing case 50 houses the battery pack 20, the slave communication device 30, and the master communication device 40 in the battery housing space inside.

[0038] Here, with reference to Figures 3 and 4, the arrangement of the battery pack 20, the slave communication device 30, and the master communication device 40 will be briefly explained. In the following, the longitudinal direction of the housing case 50 may be referred to as the X direction, the transverse direction as the Y direction, and the vertical direction as the Z direction. In this embodiment, the Y direction corresponds to the first direction, the Z direction as the second direction, and the X direction as the third direction. In the housing case 50, the inner sides on both sides in the Y direction are referred to as Y direction sides 51, with the upper Y direction side 51 in Figure 3 being referred to as Y direction side 51a, and the lower Y direction side 51 in Figure 3 being referred to as Y direction side 51b. In the housing case 50, the inner sides on both sides in the X direction are referred to as X direction sides 52, with the left X direction side 52 in Figure 3 being referred to as X direction side 52a, and the right X direction side 52 in Figure 3 being referred to as X direction side 52b.

[0039] The lower surface of the housing case 50 serves as the mounting surface for the vehicle 10. As shown in Figure 3, multiple battery blocks 21 constituting the battery pack 20 are arranged in the X direction inside the housing case 50, which is roughly rectangular in shape. In each battery block 21, the battery cells 22 constituting the battery block 21 are arranged in a stacked manner in the Y direction of the housing case 50, as shown by the dashed lines. Furthermore, each battery block 21 is arranged with a predetermined gap 25 between them. This gap 25 is a recessed gap 25 in the Z- direction (downward) when viewed from above (Z direction) of the battery unit 11.

[0040] Furthermore, a space for the slave communication device 30 is provided between the Y-direction side surface 21b of each battery block 21 (the lower side surface in Figure 3) and the Y-direction side surface 51b of the housing case 50. As shown in Figure 4, there is almost no gap between the Y-direction side surface 21a of each battery block 21 (the upper side surface in Figure 3) and the Y-direction side surface 51a of the housing case 50, and between the top surface of the battery block 21 and the top surface 53 of the housing case 50.

[0041] The slave communication device 30 is fixed to the Y-direction side 21b of each battery block 21 by screws or the like in the lateral space in the Y direction (the space between the Y-direction side 21b of the battery block 21 and the Y-direction side 51b of the housing case 50). The space between the Y-direction side 21b of the battery block 21 and the Y-direction side 51b of the housing case 50 is referred to as the slave-side passage 70. The slave-side passage 70 can be said to be surrounded in the Y direction by the Y-direction side 21b, which is the outer surface of the battery block 21, and the Y-direction side 51b, which is the inner surface of the housing case 50. The slave-side passage 70 is provided in a straight line along the Y-direction side 51b of the housing case 50, that is, along the X direction. In this embodiment, the X direction corresponds to the direction in which radio waves propagate (spread or spread) in the slave-side passage 70, and the Z direction is a direction perpendicular to the first direction (Y direction) and corresponds to a second direction perpendicular to the direction of radio wave propagation (X direction).

[0042] As shown in Figure 4, the slave communicators 30 are fixed near the center of each battery block 21 in the Z direction. As a result, the multiple slave communicators 30 are arranged in a straight line along the X direction. Therefore, the multiple slave communicators 30 and their slave-side wireless antennas 33 are arranged in a straight line along the X direction.

[0043] Furthermore, in this embodiment, a blocking plate 26 is provided as a radio wave intrusion suppression member that closes the gap 25 between the battery blocks 21 in the X direction. More specifically, the blocking plate 26 closes the gap 25 between the battery blocks 21 from the Y direction side on the side surface of the battery block 21 so as to close the gap 25 that may be recessed in the Y direction and become uneven between the battery blocks 21.

[0044] Specifically, the closing plate 26 is formed in an elongated rectangular plate shape and is configured to extend from the upper end to the lower end of the battery block 21 in the Z direction. That is, the closing plate 26 is provided across substantially the entire width in the Z direction inside the housing case 50 (battery housing space). And the closing plate 26 closes the gap 25 from the Y direction on the side of the Y-direction side surface 21b of the battery block 21 in the Y direction, that is, on the side of the mounting surface of the slave communicator 30.

[0045] At that time, so that there is no step in the Y direction between the Y-direction side surface 21b of the battery block 21 to which the slave communicator 30 is attached and the closing plate 26, that is, so that the Y-direction side surface 21b of the battery block 21 and the closing plate 26 are flush, the closing plate 26 closes the opening on the side of the slave communicator 30 in the Y direction of the gap 25. Thereby, in the slave-side passage 70 between the Y-direction side surface 51b of the housing case 50 and the Y-direction side surface 21b of the battery block 21, it is possible to prevent the formation of the gap 25 (the gap 25 recessed in the Y direction) between the battery blocks 21 and suppress the occurrence of unevenness.

[0046] As a result, the slave-side passage 70 becomes a passage surrounded by the Y-direction side surface 21b (and the closing plate 26) of the battery block 21, the Y-direction side surface 51b of the housing case 50, the upper surface 53 of the housing case 50, and the bottom surface 54 of the housing case 50. And the Y-direction side surface 21b of the battery block 21, the closing plate 26, and the housing case 50 are all made of a conductive metal material and reflect radio waves. Therefore, the slave-side passage 70 of the present embodiment has substantially the same configuration as a rectangular waveguide.

[0047] On the other hand, a space is provided between the X-direction side surface 52a of the housing case 50 in the X direction and the side surface of the assembled battery 20 (more specifically, the X-direction side surface 21c (the right side surface in FIG. 3) of the battery block 21 arranged at the X-direction end), and the master communicator 40 is arranged in this space. This space where the master communicator 40 is arranged is shown as the master-side passage 71.

[0048] Furthermore, the master communication device 40 is positioned approximately in the center of the master-side passage 71 in the Y direction (short-side direction). Also, as shown in Figure 4, the master communication device 40 is positioned approximately in the same position as the slave communication device 30 (center in Figure 4) in the Z direction (up-down direction).

[0049] The master-side passage 71 is provided in a straight line along the X-direction side 52a of the housing case 50, that is, along the Y-direction. More specifically, the master-side passage 71 is a straight passage enclosed by the X-direction side 21c of the battery block 21, the X-direction side 52a of the housing case 50, the top surface 53 of the housing case 50, and the bottom surface 54 of the housing case 50. Although not shown in the figures, components other than the master communication device 40 (for example, a junction box, etc.) may be placed in the master-side passage 71.

[0050] Since the master-side passage 71 is provided in a straight line in the Y direction, it intersects with the slave-side passage 70 at the corner of the housing case 50 (the lower left corner in Figure 3). As will be described later, the master-side passage 71 and the slave-side passage 70 have a cross-section large enough to allow radio waves (radio waves used in wireless communication) transmitted and received from the master communication device 40 to the slave communication device 30 to pass through. In other words, as shown in Figure 3, the radio wave propagation path (shown by the dashed line) in this embodiment is bent in a roughly L-shape along the master-side passage 71 and the slave-side passage 70. To put it another way, the propagation path is provided in a roughly L-shape along the X-direction side surface 52a and the Y-direction side surface 51b of the housing case 50.

[0051] Incidentally, since the housing case 50 is made of a conductor such as metal, it can suppress the effects of external noise and the effects of reflected waves from metal materials outside the housing case 50 (multipath phenomenon). However, because the internal space of the housing case 50 is a closed space made of conductors, radio wave interference may occur between the radio waves of wireless communication and their reflected waves inside, potentially weakening the received power (radio waves). In other words, the communication quality may deteriorate.

[0052] This phenomenon will be explained in detail. As shown in Figure 5, the slave-side passage 70 through which the radio waves are received by the slave communication device 30 can be considered as a rectangular waveguide with a rectangular cross-section, enclosed by the Y-direction side 21b of the battery block 21 and the Y-direction side 51b of the housing case 50, as mentioned above. In a waveguide, the frequency of radio waves that can propagate is not just any frequency, but is limited to above a certain level. The lower limit of the frequency that can propagate in a particular propagation mode of a waveguide is called the cutoff frequency fc for that waveguide and that radio wave mode, and the wavelength of that frequency in free space is called the cutoff wavelength λc.

[0053] As shown in Figure 5, if the width dimension in the Y direction of the slave-side passage 70 is "a (mm)" and the height dimension in the Z direction is "b (mm)", then the cutoff wavelength λc can be calculated using formula (eq. 1). The cutoff frequency fc can be calculated by dividing the speed of the radio wave by the cutoff wavelength λc. In formula (eq. 1), m and n represent the number of waves in the Y direction and Z direction, respectively, and these are called the number of modes of propagation mode.

[0054] Here, we will illustrate with Figure 6 how the cutoff frequency fc changes in relation to the height dimension b in the Z direction. As shown in Figure 6, when the height dimension b is 123 mm and mode 1 (m=0, n=1), the cutoff frequency fc is 1.22 GHz. Since this is mode 1, it can be imagined as having zero waves in the Y direction (m=0) and one wave in the Z direction (n=1). Similarly, when the height dimension b is 123 mm and mode 2 (m=0, n=2), the cutoff frequency fc is 2.44 GHz. Since this is mode 2, it can be imagined as having zero waves in the Y direction (m=0) and two waves in the Z direction (n=2).

[0055] Furthermore, when the height dimension b is 100 mm and mode 1 (m=0, n=1), the cutoff frequency fc is 1.50 GHz, and when the height dimension b is 100 mm and mode 2 (m=0, n=2), the cutoff frequency fc is 3.00 GHz. Note that the width dimension a is 30 mm, which is less than half of the cutoff wavelength λc, so m=0. In addition, mode 1 (one wave) is sometimes referred to as single mode, and modes 2 and above (two or more waves) are sometimes referred to as multimode.

[0056] Incidentally, when radio waves interfere with and cancel each other out by reflected waves (radio waves with opposite phase that are reflected from the housing case 50, etc.), the strength of the received power (electric field strength) becomes extremely weak, and there are locations where reception becomes impossible. The location where the strength of the received power becomes extremely weak and reception becomes impossible is called a null (also called a null point). Furthermore, in the case of a rectangular waveguide such as the slave-side passage 70, it has been found that when it is a single-mode device, nulls occur at regular intervals, but when it is a multi-mode device, the location where nulls occur becomes complex and difficult to predict.

[0057] For example, Figure 7 shows a map of the received power intensity (in dB (V / m)) when the height dimension b is 123 mm. The upper map in Figure 7 is for the case where the communication frequency f1 in wireless communication is 2.4 GHz (2400 MHz), that is, when the wavelength λ1 of the radio wave is approximately 124.9 mm. Note that the height dimension b (= 123 mm) corresponds to approximately 0.98 times the wavelength λ1 of the radio wave. In other words, the height dimension b is more than half of the wavelength λ1 of the radio wave, but less than the wavelength λ1 of the radio wave. Also, referring to Figure 6, when the height dimension b is 123 mm, the cutoff frequency fc for mode 2 is 2.44 GHz, and the cutoff frequency fc for mode 1 is 1.22 GHz. Therefore, in Figure 7, the upper map is a single-mode map.

[0058] Furthermore, the middle map in Figure 7 shows the case where the communication frequency f2 in wireless communication is 2.44 GHz, that is, when the wavelength λ2 of the radio wave is approximately 122.9 mm. Note that approximately 1 times the wavelength λ2 of the radio wave corresponds to the height dimension b (= 123 mm). In other words, the height dimension b is almost the same as the wavelength λ2 of the radio wave. Referring to Figure 6, the cutoff frequency fc of mode 2 when the height dimension b is 123 mm is 2.44 GHz, so in Figure 7, the middle map is a multimode map.

[0059] Furthermore, the lower map in Figure 7 shows the case where the communication frequency f3 in wireless communication is 2.48 GHz, that is, when the wavelength λ3 of the radio wave is approximately 120.9 mm. Note that approximately 1.02 times the wavelength λ3 of the radio wave corresponds to the height dimension b (= 123 mm). In other words, the height dimension b is greater than or equal to the wavelength λ2 of the radio wave. In Figure 7, the lower map, like the middle map, is a multimode map.

[0060] Referring to Figure 7, the darker colored areas correspond to nulls. For example, the nodes enclosed by dashed lines are nulls. Referring to the upper map in Figure 7, it can be seen that nulls occur at regular intervals in the X direction in the slave-side passage 70. It can also be seen that nulls occur at the upper and lower ends in the Z direction. Note that the left end of the slave-side passage 70 is connected to the master-side passage 71 and is partially multimode, making it difficult to determine the location of the nulls.

[0061] On the other hand, referring to the middle and lower sections of Figure 7, it can be seen that the location of nulls is difficult to pinpoint in multimode. It appears that nulls are barely occurring near the center in the Z direction, but even then, the location of the nulls is meandering or interrupted, making it difficult to determine. Furthermore, the location of nulls differs between single-mode and multimode.

[0062] Furthermore, since the frequency band of the communication frequency f used in this embodiment is 2402 MHz to 2480 MHz, if the height dimension b is 123 mm, wireless communication may be performed in either single mode or multi-mode. For this reason, if the height dimension b is 123 mm, the null may overlap with the slave communicator 30, in which case the communication quality will deteriorate.

[0063] Next, Figure 8 shows a map illustrating the strength of the received power (in dB (V / m)) when the height dimension b is 100 mm. The upper map in Figure 8 is for the case where the communication frequency f1 is 2.4 GHz (2400 MHz), that is, when the wavelength λ1 of the radio wave is approximately 124.9 mm. Note that the height dimension b (= 100 mm) corresponds to approximately 0.80 times the wavelength λ1 of the radio wave. In other words, the height dimension b is more than half of the wavelength λ1 of the radio wave, but less than the wavelength λ1 of the radio wave. Also, referring to Figure 6, when the height dimension b is 100 mm, the cutoff frequency fc for mode 2 is 3.00 GHz, and the cutoff frequency fc for mode 1 is 1.50 GHz. Therefore, in Figure 8, the upper map is a single-mode map.

[0064] Furthermore, the middle map in Figure 8 shows the case where the communication frequency f2 in wireless communication is 2.44 GHz, that is, when the wavelength λ2 of the radio wave is approximately 122.9 mm. Note that approximately 0.81 times the wavelength λ2 of the radio wave corresponds to the height dimension b (= 100 mm). Therefore, as mentioned above, the middle map in Figure 8 is a single-mode map.

[0065] Furthermore, the lower map in Figure 8 shows the case where the communication frequency f3 in wireless communication is 2.48 GHz, that is, when the wavelength λ3 of the radio wave is approximately 120.9 mm. Note that approximately 0.83 times the wavelength λ3 of the radio wave corresponds to the height dimension b (= 100 mm). Therefore, as mentioned above, the lower map in Figure 8 is a single-mode map.

[0066] Referring to Figure 8, it can be seen that in the upper, middle, and lower maps, nulls occur at regular intervals in the X direction in the slave-side passage 70. Furthermore, the position of the nulls is the same in the upper, middle, and lower maps. In other words, the position of the nulls is common for communication frequencies f1 to f3. As mentioned above, the left end of the slave-side passage 70 is connected to the master-side passage 71 and is partially multimode, making it difficult to determine the position of the nulls.

[0067] Furthermore, since the frequency band of the communication frequency f used in this embodiment is 2402 MHz to 2480 MHz, when the height dimension b is 100 mm, wireless communication will always be performed in single mode. For this reason, when the height dimension b is 100 mm, if the position of the null is identified and the slave communicator 30 is positioned to avoid the null position, a decrease in communication quality can be avoided.

[0068] Therefore, the slave-side passage 70 in this embodiment is set to have a height dimension b such that communication is always performed in single mode. Specifically, if the wavelength of the radio waves used in wireless communication is λ, the height dimension b of the slave-side passage 70 in the Z direction is set to be 1 / 2 × λ ​​or more and less than 1 × λ. Note that the communication frequency f in this embodiment has a range from 2402 MHz to 2480 MHz, so the upper and lower limits are set taking this range into consideration. In other words, if the longest wavelength of the radio waves used in wireless communication is λmax and the shortest wavelength is λmin, the height dimension b of the slave-side passage 70 in the Z direction is set to be 1 / 2 × λmax or more and less than 1 × λmin.

[0069] Furthermore, in the slave-side passage 70, the width dimension a between the Y-direction side surface 51b of the housing case 50 and the Y-direction side surface 21b of the battery block 21 is less than 1 / 2 × λ. This is also because the communication frequency f has a range from 2402 MHz to 2480 MHz, and the width dimension a is set to less than 1 / 2 × λmin.

[0070] Furthermore, as shown in Figure 8, there are no nulls near the center in the Z direction, and the received power is strong there. Therefore, the slave communication device 30 is fixed at the center position in the Z direction of the slave-side passage 70. Also, since the position of the null does not change in the X direction, the position of the null where the received power is weak is identified through experiments, and the position of the slave communication device 30 in the X direction is determined and fixed to avoid the null position.

[0071] Next, the effects of this embodiment are described below.

[0072] When the wavelength of radio waves used in wireless communication is denoted as λ, the height dimension b of the slave-side passage 70 in the Z direction is set to be greater than or equal to 1 / 2 × λ ​​and less than 1 × λ. This ensures that the slave-side passage 70 always has a height dimension b such that single-mode communication occurs. Therefore, the location of nulls can be easily identified, and the slave communicator 30 can be positioned in a suitable location while avoiding nulls. Thus, the degradation of communication quality due to reflected waves can be suppressed.

[0073] In this embodiment, the communication frequency f has a range from 2402 MHz to 2480 MHz. Therefore, when the longest wavelength of the radio waves used in wireless communication is defined as λmax and the shortest wavelength as λmin, the height dimension b of the slave-side passage 70 in the Z direction is set to be 1 / 2 × λmax or greater and less than 1 × λmin. As a result, even if the communication frequency f is changed within a predetermined frequency band range, it can remain in single mode, and a deterioration in communication quality can be suppressed.

[0074] The Z-direction is the vertical direction of the housing case 50. The bottom surface of the slave-side passage 70 is formed by the bottom surface 54 of the housing case 50, and the top surface of the slave-side passage 70 is formed by the top surface 53 of the housing case 50. Therefore, by adjusting the height dimension of the housing case 50, the height dimension of the slave-side passage 70 can also be adjusted.

[0075] After identifying the location of the null, the position of the slave communicator 30 in the X direction is determined to avoid the null location. This helps to suppress a decrease in communication quality.

[0076] The blocking plate 26 blocks the gap 25 (a gap that is recessed in the Y direction) between the battery blocks 21 in the slave-side passage 70 from the Y direction. Therefore, when radio waves from the slave communicator 30 or master communicator 40 pass through the slave-side passage 70, it is possible to suppress the phase shift of the reflected waves caused by the irregularities in the Y direction due to the gap 25 between the battery blocks 21. This suppresses radio wave interference and allows the received power to be maintained in a good state.

[0077] The blocking plate 26 is closed such that the step difference with the Y-direction side surface 21b of the battery block 21 to which the slave communication device 30 is attached is within a predetermined allowable range. More specifically, the blocking plate 26 is configured such that the step difference with the Y-direction side surface 21b of the battery block 21, which is the contact surface for the slave communication device 30, is λ / 8 or less. This eliminates the gap 25 with a deep Y-direction depth in the slave-side passage 70, suppressing radio wave interference and maintaining good received power.

[0078] (Modification of the first embodiment) In the above embodiment, the position of the slave communication device 30 in the Z direction was used as the center, but it does not have to be the center. For example, the slave communication device 30 may be arranged within a range of ±λ × 0.2 in the Z direction, with the center position of the slave-side passage 70 in the Z direction as the center.

[0079] Furthermore, if the wavelength in free space (free space wavelength) is denoted as λ0 and the wavelength inside the tube in the slave-side passage 70 is denoted as λg, then the slave communication device 30 should be positioned within a range of ±λg × 0.16 in the Z direction, centered on the center position in the Z direction of the slave-side passage 70.

[0080] The details are explained below. Figure 9 shows "λ0", "λg", height dimension b, and "θ". Figure 9 is an enlarged view of a part of the slave-side passage 70. The in-pipe wavelength λg and the free-space wavelength λ0 have the relationship shown in equation (eq. 2). Note that the free-space wavelength λ0 is the wavelength of the radio wave being used and can be calculated from the communication frequency f. The solid line shows the positive wavefront of the radio wave (incident wave), and the dashed line shows the negative wavefront.

[0081] Figure 10 shows the relationship between the received power intensity and the position in the Z-direction of the slave-side passage 70. The vertical axis shows the normalized electric field strength (unit: dB (V / m)) corresponding to the received power intensity, and the horizontal axis shows the position in the Z-direction. As shown in Figure 10, the normalized electric field strength at the center position T1 of the slave-side passage 70 in the Z-direction is at its peak value. Within a range of ±λg × 0.16 in the Z-direction centered on the center position T1, the electric field strength is approximately -3 dB lower than the peak value, and outside this range, it is more than -3 dB lower. A range of approximately -3 dB is sufficient for practical use in wireless communication propagation. Therefore, in this modified example, it is sufficient for the slave communication device 30 to be positioned within a range of ±λg × 0.16 in the Z-direction centered on the center position T1 of the slave-side passage 70 in the Z-direction.

[0082] In the above embodiment, the location of the null point where the received power strength weakens was identified by experimentation, and the slave communication device 30 was positioned to avoid the null point. As a variation of this, when n is a natural number and λg is the wavelength inside the tube, the slave communication device 30 may be positioned within the range of ((2n-1) / 4) × λg ± 0.12 × λg from the X-direction end of the slave-side passage 70.

[0083] Let me explain in detail. Figure 11 shows the relationship between the strength of the received power and the position in the X direction of the slave-side passage 70. The vertical axis shows the normalized electric field strength (unit: dB (V / m)) corresponding to the strength of the received power, and the horizontal axis shows the position from the end of the slave-side passage 70 in the X direction. Note that the position R0 at the right end of Figure 11 corresponds to the position R0 at the right end of the slave-side passage 70 in Figure 4. In other words, it is assumed that the master communication device 40 is located on the left side of Figure 11. Also, in Figure 11, the end of the slave-side passage 70 in the X direction means the end opposite to the direction in which the radio waves are incident.

[0084] As shown in Figure 11, it was found that the normalized electric field strength peaks at positions R1, R2, etc., of ((2n-1) / 4) × λg from position R0 at the right end of the slave-side passage 70 in the X direction. The wavelength λg inside the tube can be calculated from equation (eq.2) as described above.

[0085] Furthermore, within a range of ±λg × 0.12 in the X direction, centered on positions R1, R2, etc., the peak value is reduced by up to approximately -3 dB, and outside this range, it is reduced by more than -3 dB. Therefore, in this modified example, it is sufficient that the slave communication device 30 is positioned within a range of ((2n-1) / 4) × λg ± 0.12 × λg from the X-direction end of the slave-side passage 70.

[0086] (Second Embodiment) A second embodiment is described in which the configuration of the battery unit 11 of the first embodiment has been partially modified. Components that are the same as in the first embodiment are denoted by the same reference numerals, and their descriptions and drawings are omitted.

[0087] Figure 12 shows a block diagram illustrating the configuration of the battery unit in the second embodiment. As shown in Figure 12, in the slave communication device 30, a switch SW1 is provided on the electrical path connecting the slave-side wireless IC 32 and the slave-side wireless antenna 33, acting as a switch to switch between energizing and disconnecting the power supply between the slave-side wireless IC 32 and the slave-side wireless antenna 33. This switch SW1 is controlled on and off by the monitoring IC 31 or the slave-side wireless IC 32. In this embodiment, the on and off is controlled by the slave-side wireless IC 32. In the second embodiment, the monitoring IC 31 or the slave-side wireless IC 32 corresponds to the microcontroller unit.

[0088] The slave-side wireless IC 32 turns on switch SW1 only when sending or receiving data with the master communication device 40, and turns off switch SW1 at all other times.

[0089] Referring to Figure 13, the on / off timing of switch SW1 will be explained. Note that in Figure 13, for the sake of explanation, there are two slave communicators 30 (slave communicator 30a, slave communicator 30b), but more than two may be provided.

[0090] As shown in Figure 13, the master communication device 40 and the slave communication devices 30a and 30b perform connection processing to establish a connection after startup. Specifically, first, the master communication device 40 performs a scan operation (slave detection operation) (step S11), and the slave communication devices 30a and 30b each perform an advertisement operation (connection information transmission operation) (step S12). The start of the scan operation may be earlier than the start of the advertisement operation, or at approximately the same time. It may also be later than the start of the advertisement operation.

[0091] The advertising operation is the operation in which slave communicators 30a and 30b send an advertisement packet (ADV_PKT) via broadcast communication to inform the master communicator 40 of their presence. The advertisement packet contains ID information (identification numbers) of themselves (slave communicators 30a and 30b) and the master communicator 40.

[0092] When the master communication device 40 detects advertisement packets, i.e., slave communication devices 30a and 30b, through a scan operation (step S13), it sends a connection request signal (CONNECT_REQ) to the detected slave communication devices 30a and 30b.

[0093] Then, when the slave communicators 30a and 30b receive a connection request signal, a connection, that is, a connection of the wireless communication path, is established between one of the slave communicators 30a or 30b and the master communicator 40 (step S14). Once the connection is established, the slave communicators 30a and 30b stop transmitting advertisement packets. The slave communicators 30a and 30b periodically transmit advertisement packets until the connection is established. During this series of connection processes (steps S11 to S14), the respective switches SW1 of the slave communicators 30a and 30b are turned ON.

[0094] After the connection process is completed and the connection is established, the slave communicators 30a and 30b switch SW1 on and off according to a predetermined schedule. The schedule is like a time schedule that specifies the order in which the slave communicators 30a and 30b will communicate and the time for each communication. The schedule only needs to be stored in the slave communicators 30a and 30b in advance. Alternatively, during the connection process, the master communicator 40 may determine the schedule and transmit it to the slave communicators 30a and 30b for them to store. The slave communicators 30a and 30b turn on switch SW1 during their respective communication times according to the schedule. The time for turning on switch SW1 is determined according to the schedule.

[0095] In Figure 13, first, the slave communicator 30a turns on switch SW1 according to the schedule (step S15). Meanwhile, the master communicator 40 selects the slave communicator 30a to communicate with according to a predetermined schedule (step S16). Then, the master communicator 40 wirelessly transmits data (data request) to the slave communicator 30a, which is the communication partner, via the master-side wireless antenna 43, requesting the acquisition and transmission of battery information (step S16).

[0096] When the slave communicator 30a, the recipient (communication partner), receives a data request via the slave-side wireless antenna 33, it detects battery information according to the data request and transmits monitoring data including the detected battery information to the master communicator 40 (step S17). Thereafter, the exchange of data requests and replies containing data including battery information is repeated until a predetermined communication time has elapsed. When the communication time for which the slave communicator 30a is the communication partner has ended according to the schedule, it turns off switch SW1 (step S18).

[0097] Next, the slave communicator 30b turns on switch SW1 according to the schedule (step S19). Meanwhile, the master communicator 40 selects the slave communicator 30b to communicate with according to a predetermined schedule (step S20). From here on, although not shown in the diagram, data transmission and reception are performed in the same manner as the slave communicator 30a. Similarly, when the communication time for which the slave communicator 30b is to communicate with another device ends, it turns off switch SW1.

[0098] The operation and effects of switching SW1 on and off will now be explained. First, Figure 14 shows a comparative example where switch SW1 is not provided (where power is continuously supplied between the slave-side wireless IC 32 and the slave-side wireless antenna 33). In Figure 14, the horizontal axis indicates the position of the slave-side passage 70 in the X direction, and the vertical axis indicates the strength of the received power (electric field strength (dB (V / m))). Furthermore, the slave communication devices 30 are assumed to be located at positions P1, P2, P3, and P4 in the X direction.

[0099] As shown in Figure 14, it can be seen that the received power intensity reaches its peak value at each position P1, P2, P3, and P4 of the slave communication device 30. However, the peak value gradually decreases as you move towards the right end, that is, as you move away from the master communication device 40. This is thought to be because when power is supplied between the slave-side wireless IC 32 and the slave-side wireless antenna 33, the radio waves are absorbed towards the slave-side wireless IC 32 via the slave-side wireless antenna 33.

[0100] Next, Figure 15 shows the operation of this embodiment. In Figure 15, as in Figure 14, the horizontal axis indicates the position of the slave-side passage 70 in the X direction, and the vertical axis indicates the strength of the received power. The slave communicators 30 are assumed to be located at positions P1, P2, P3, and P4 in the X direction. In Figure 15, the switches SW1 of each slave communicator 30 located at positions P1, P2, and P3 are assumed to be off, and the switch SW1 of the slave communicator 30 located at the rightmost position P4 is assumed to be on.

[0101] As shown in Figure 15, it can be seen that the received power intensity reaches its peak value at each of the positions P1, P2, P3, and P4 of the slave communicator 30. Furthermore, in Figure 15, the peak value does not decrease as much even when approaching the right edge, compared to the comparative example in Figure 14. This is thought to be because the switch SW1 of each slave communicator 30 located at positions P1, P2, and P3 is turned off, and therefore radio waves are not absorbed by these slave communicators 30.

[0102] As described above, by providing a switch SW1 between the slave-side wireless IC 32 and the slave-side wireless antenna 33, and turning off the switch SW1 when not communicating, it is possible to suppress a decrease in the received power of each slave communication device 30. In other words, it is possible to suppress a decrease in communication quality.

[0103] (Modifications) Modifications of each of the above embodiments are shown below.

[0104] - In the above embodiment, the bottom and top surfaces of the slave-side passage 70 were formed by the bottom surface 54 and top surface 53 of the housing case 50, respectively. As a modification, at least one of the bottom or top surfaces of the slave-side passage 70 may be provided with a conductive height adjustment member to adjust the height dimension of the slave-side passage 70.

[0105] For example, as shown in Figures 16 and 17, a long metal plate 75 may be provided at the top of the slave-side passage 70 as a height adjustment member for adjusting the height dimension b of the slave-side passage 70. However, it is not necessary to use a long plate 75; for example, instead of the long plate 75, a conductive refrigerant passage through which a refrigerant (such as cooling water) passes may be placed at the top of the slave-side passage 70, and the height dimension b of the slave-side passage 70 may be adjusted by the refrigerant passage. In this case, the refrigerant passage becomes the height adjustment member. In other words, the height dimension b can be adjusted by a conductor extending in the X direction.

[0106] - The slave-side passage in the above embodiment may be provided between the battery blocks 21. For example, as shown in Figure 18, the battery blocks 21A and 21B are arranged separately on both sides of the housing case 50 in the Y direction (both the upper and lower sides in Figure 18). Four battery blocks 21A are arranged on one side in the Y direction with a predetermined gap 125 between them, and four battery blocks 21B are arranged on the other side in the Y direction with a predetermined gap 125 between them.

[0107] As a result, a slave-side passage 170 extending along the Y direction is provided between the battery blocks 21A and 21B. The slave communication device 30 is positioned in this slave-side passage 170. The width dimension a of this slave-side passage 170 (the dimension between battery block 21A and battery block 21B) is less than the wavelength λ × 1 / 2. The height dimension b of this slave-side passage 170 (the dimension in the Z direction) is greater than or equal to 1 / 2 × λ ​​and less than 1 × λ, as in the first embodiment. The gap 125 between the battery blocks 21A and 21B is closed by a closing plate 126, as in the first embodiment.

[0108] - The slave-side passages in the above embodiment may be provided on both sides of the battery block 21. For example, as shown in Figure 19, slave-side passages 70a and 70b are provided on both sides of the housing case 50 in the Y direction (upper and lower sides in Figure 19). That is, the slave-side passage 70a is provided between the Y-direction side surface 51a of the housing case 50 and the Y-direction side surface 21a of the battery block 21. Also, the slave-side passage 70b is provided between the Y-direction side surface 51b of the housing case 50 and the Y-direction side surface 21b of the battery block 21. The width dimension a and height dimension b of the slave-side passages 70a and 70b, the arrangement of the slave communication device 30, etc., are the same as in the first embodiment. The gap 25 between the battery blocks 21 is closed by closing plates 26a and 26b, as in the first embodiment.

[0109] - The slave-side passage 70 in the above embodiment may be provided between the upper surface of the battery block 21 and the upper surface 53 of the housing case 50. For example, as shown in Figures 20 and 21, the slave communication device 30 can be placed on the upper surface of the battery block 21 and surrounded on both sides in the Y direction by elongated partition plates 91 and 92. The space enclosed by the partition plates 91 and 92, the upper surface of the battery block 21, and the upper surface 53 of the housing case 50 is the slave-side passage 270.

[0110] In the cases of Figures 20 and 21, the Z direction is the first direction and the Y direction is the second direction. In this case, the dimension b1 in the Y direction between partition plate 91 and partition plate 92 is set to be 1 / 2 × λ ​​or more and less than 1 × λ. The dimension a1 in the Z direction between the upper surface of the battery block 21 and the upper surface 53 of the housing case 50 is less than 1 × λ.

[0111] In Figure 20, a blocking plate 81 is provided as an electromagnetic wave intrusion suppression member that blocks the gap 25 between the battery blocks 21 from the Z direction (from above). The blocking plate 81 is made of a conductive material such as metal and is formed in an elongated plate shape along the Y direction. Since the gap 25 between the battery blocks 21 is formed to extend in the Y direction, the blocking plate 81 is also formed in an elongated plate shape along the gap 25 between each battery block 21. The length dimension of the blocking plate 81 (length dimension in the Y direction) is the same as that of the battery block 21. In this embodiment, in order to block all the gaps 25 between each battery block 21 in the slave-side passage 270, each gap 25 is blocked by multiple blocking plates 81.

[0112] In addition, either or both of the partition plates 91 and 92 may be used as the inner side surface of the storage case 50.

[0113] - In the above embodiment, it is not necessary to provide a closing plate 26 that closes the gap 25.

[0114] The following is an addition regarding the technical ideas that can be derived from the above embodiments and modifications. [Configuration 1] A battery unit (11) comprising a battery section (20, 21, 22), a slave communicator (30) for detecting battery information, a master communicator (40) for controlling the slave communicator, and a conductive housing (50) for housing them, wherein the master communicator transmits a request command for battery information to the slave communicator via wireless communication, and the slave communicator, upon receiving the request command, detects the battery information based on the request command and transmits it via wireless communication, wherein one or more of the battery sections (20, 21, 22) are housed inside the housing, the slave communicator is positioned in a slave-side passage (70) surrounded by the inner surface of the housing and the outer surface of the battery section in a first direction, or a slave-side passage surrounded by the outer surface of one battery section and the outer surface of another battery section, and the radio waves of the wireless communication transmitted from the master communicator pass through at least the slave-side passage as a propagation path and are received by the slave communicator. A battery unit in which, when the wavelength of the radio waves used in the wireless communication is λ, the dimensions of the slave-side passage in the second direction perpendicular to the first direction are 1 / 2 × λ ​​or more and less than 1 × λ. [Configuration 2] The battery unit according to Configuration 1, wherein the second direction is the vertical direction of the housing, the bottom surface of the slave-side passage in the second direction is made up of the bottom surface of the housing, the top surface of the slave-side passage in the second direction is made up of the top surface of the housing, and the height dimension from the bottom surface to the top surface of the housing is 1 / 2 × λ ​​or more and less than 1 × λ. [Configuration 3] The battery unit according to Configuration 1 or 2, wherein the slave communication device is arranged in the second direction within a width range of ±λ × 0.2 centered on the center position in the second direction of the slave-side passage. [Configuration 4] A battery unit according to any one of Configurations 1 to 3, wherein in the slave-side passage, the width dimension between the inner surface of the housing and the outer surface of the battery section, or the width dimension between the outer surface of the battery section and the outer surface of another battery section, is less than 1 / 2 × λ.[Configuration 5] The battery unit according to any one of Configurations 1 to 4, wherein the slave-side passage is provided in a straight line along the inner surface of the housing or the outer surface of the battery section until it abuts against another inner surface of the housing or another outer surface of the battery section, and when n is a natural number and λg is the tube wavelength of the radio waves in the slave-side passage, the slave communication device is arranged within the range of ((2n-1) / 4) × λg ± 0.12 × λg from the end of the slave-side passage. [Configuration 6] The battery unit according to any one of Configurations 1 to 5, further comprising a radio wave intrusion suppression member (26, 81) that blocks at least a portion of the gap (25) between the battery section and the housing and the gap (25) between the battery sections. [Configuration 7] The battery unit according to any one of Configurations 1 to 6, wherein the slave communication device comprises an antenna (33) for transmitting and receiving radio waves, a microcontroller unit (31, 32) for performing various processes, and a switch (SW1) for switching the connection between the antenna and the microcontroller unit, wherein the microcontroller unit turns on the switch to connect the antenna and the microcontroller unit when transmitting and receiving radio waves via wireless communication, and turns off the switch to disconnect the connection between the antenna and the microcontroller unit when not transmitting and receiving radio waves via wireless communication. [Configuration 8] The battery unit according to any one of Configurations 1 to 7, wherein the second direction is the vertical direction of the housing, and a conductive height adjustment member (75) for adjusting the height dimension of the slave-side passage is provided on at least one of the bottom side and the top side of the slave-side passage in the second direction. [Configuration 9] The battery unit according to any one of Configurations 1 to 8, wherein the second direction is a direction perpendicular to the direction of propagation of the radio waves in the slave-side passage.

[0115] This disclosure is described in accordance with the embodiments, but it is understood that this disclosure is not limited to such embodiments or structures. This disclosure also includes various modifications and variations within the equivalence. In addition, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and concept of this disclosure.

Claims

1. A battery unit (11) comprising: battery sections (20, 21, 22); a slave communicator (30) for detecting battery information; a master communicator (40) for controlling the slave communicator; and a conductive housing (50) housing them, wherein the master communicator transmits a request command for battery information to the slave communicator via wireless communication, and the slave communicator, upon receiving the request command, detects the battery information based on the request command and transmits it via wireless communication, wherein one or more of the battery sections (20, 21, 22) are housed inside the housing; the slave communicator is positioned in a slave-side passage (70) surrounded in a first direction by the inner surface of the housing and the outer surface of the battery section, or in a slave-side passage surrounded by the outer surface of one battery section and the outer surface of another battery section; and the radio waves of the wireless communication transmitted from the master communicator pass through at least the slave-side passage as a propagation path and are received by the slave communicator. A battery unit in which, when the wavelength of the radio waves used in the aforementioned wireless communication is λ, the dimensions of the slave-side passage in the second direction perpendicular to the first direction are 1 / 2 × λ ​​or more and less than 1 × λ.

2. The battery unit according to claim 1, wherein the second direction is the vertical direction of the housing, the bottom surface of the slave-side passage in the second direction is the bottom surface of the housing, the top surface of the slave-side passage in the second direction is the top surface of the housing, and the height dimension from the bottom surface to the top surface of the housing is 1 / 2 × λ ​​or more and less than 1 × λ.

3. The battery unit according to claim 1, wherein the slave communication device is arranged in a second direction within a width of ±λ × 0.2 with respect to the central position in the second direction of the slave-side passage.

4. The battery unit according to claim 1, wherein in the slave-side passage, the width dimension between the inner surface of the housing and the outer surface of the battery unit, or the width dimension between the outer surface of the battery unit and the outer surface of another battery unit, is less than 1 / 2 × λ.

5. The battery unit according to claim 1, wherein the slave-side passage is provided in a straight line along the inner surface of the housing or the outer surface of the battery section until it abuts against another inner surface of the housing or another outer surface of the battery section, and when n is a natural number and λg is the wavelength of the radio waves within the slave-side passage, the slave communication device is positioned within the range of ((2n-1) / 4) × λg ± 0.12 × λg from the end of the slave-side passage.

6. A battery unit according to any one of claims 1 to 5, further comprising radio wave intrusion suppression members (26, 81) that block at least a portion of the gap (25) between the battery section and the housing and the gap (25) between the battery sections.

7. The battery unit according to any one of claims 1 to 5, wherein the slave communication device comprises an antenna (33) for transmitting and receiving radio waves, a microcontroller unit (31, 32) for performing various processes, and a switch (SW1) for switching the connection between the antenna and the microcontroller unit, wherein the microcontroller unit turns on the switch to connect the antenna and the microcontroller unit when transmitting and receiving radio waves via wireless communication, and turns off the switch to disconnect the connection between the antenna and the microcontroller unit when not transmitting and receiving radio waves via wireless communication.

8. The battery unit according to any one of claims 1 to 5, wherein the second direction is the vertical direction of the housing, and in the second direction, at least one of the bottom side and the top side of the slave-side passage is provided with a conductive height adjustment member (75) for adjusting the height dimension of the slave-side passage.

9. The battery unit according to any one of claims 1 to 5, wherein the second direction is a direction perpendicular to the direction of propagation of the radio waves in the slave-side passage.

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