Battery unit

Abstract

A battery unit (11) comprises: battery portions (20, 21, 22); slave communication devices (30) that detect battery information and transmit the battery information through wireless communication; a master communication device (40) that receives battery information from the slave communication devices through wireless communication; and an electrically conductive housing (50) that houses the battery units, the slave communication devices, and the master communication device. Inside the housing, a first region (61) in which either the slave communication devices or the master communication device is disposed is wider than a second region (62, 162) in which the other is disposed, and boundary portions (63, 163) between the first region and the second region are configured to narrow from the first region toward the second region.

Description

Battery unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2024-124732, filed on July 31, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a battery unit.

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

[0004] Japanese Patent Application Laid-Open No. 2022-83848

[0005] When applying a battery monitoring system that performs wireless communication to a vehicle battery unit, it is considered to prevent external noise by making the battery unit's housing out of metal and accommodating the battery monitoring system inside the housing.

[0006] However, even if the battery monitoring system is housed in a metal housing, communication quality may deteriorate depending on the shape of the housing space and the arrangement and shape of the battery cells and battery modules inside the housing.

[0007] For example, if there is a large difference in size between the first area where the transmitter is located and the second area where the receiver is located, and the area suddenly narrows at the boundary between the first and second areas, there is a problem that radio wave loss increases and communication quality deteriorates.

[0008] The present disclosure has been made in consideration of the above circumstances, and a main object of the present disclosure is to provide a battery unit that can suppress deterioration of communication quality.

[0009] The first battery unit for solving the above problem is a battery unit comprising a battery section, a slave communication device that detects battery information and transmits it via wireless communication, a master communication device that receives battery information from the slave communication device via wireless communication, and a conductive housing that houses them, wherein within the housing, a first region in which either the slave communication device or the master communication device is arranged is wider than a second region in which the other is arranged, and the boundary between the first region and the second region is configured to narrow from the first region toward the second region.

[0010] This allows the radio waves output from the first region to converge at the boundary and propagate to the second region. Furthermore, the radio waves output from the second region can be directed to a certain extent without being scattered randomly in multiple directions at the boundary, thereby reducing radio wave loss.

[0011] A second battery unit for solving the above problem comprises a battery section, a slave communication device that detects battery information and transmits it via wireless communication, a master communication device that receives battery information from the slave communication device via wireless communication, and a conductive housing that houses them, wherein inside the housing, a first area in which either the slave communication device or the master communication device is located is larger than a second area in which the other is located, and a relay member is located at the boundary between the first area and the second area that collects radio waves from one area and emits the collected radio waves toward the other area.

[0012] The relay member can reduce the loss of radio waves.

[0013] 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 unit, Fig. 3 is a plan view showing the interior of the battery unit, Fig. 4 is a side view showing the interior of the battery unit, Fig. 5 is a plan view showing the interior of a battery unit of a comparative example, Fig. 6 is a diagram showing the state of the electric field in the X-Y direction of the comparative example, Fig. 7 is a diagram showing the state of the electric field in the X-Z direction of a first region of the comparative example, Fig. 8 is a diagram showing the state of the electric field in the Y-Z direction of a second region of the comparative example, Fig. 9 is a diagram showing the state of the electric field in the X-Y direction of the first embodiment, Fig. 10 is a diagram showing the relationship between frequency and loss, and Fig. 11 is a diagram showing the battery unit of a second embodiment. 12 is a diagram showing the relationship between frequency and loss in the second embodiment, FIG. 13 is a plan view showing the interior of the battery unit in the third embodiment, FIG. 14 is a plan view showing the interior of the battery unit in a modified example, FIG. 15 is a plan view showing the interior of the battery unit in a modified example, FIG. 16 is a plan view showing the interior of the battery unit in a modified example, FIG. 17 is a plan view showing the interior of the battery unit in a modified example, FIG. 18 is a plan view showing the interior of the battery unit in a modified example, FIG. 19 is a side view showing the interior of the battery unit in a modified example, and FIG. 20 is a plan view showing the interior of the battery unit in a modified example.

[0014] Hereinafter, embodiments of the battery unit according to the present disclosure will be described in detail with reference to the drawings. Note that, among 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 battery unit 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.

[0015] (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 unit 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."

[0016] The battery unit 11 is mounted on the vehicle 10 as a driving power source for the vehicle 10. In Fig. 1, the battery unit 11 is disposed, for example, in the front compartment. However, the battery unit 11 may also be disposed in the rear compartment, under a seat, under the floor, or the like.

[0017] The battery unit 11 is a chargeable and dischargeable DC voltage source that includes a battery pack 20 (described later). The battery unit 11 supplies power to the electrical loads of the vehicle 10. The battery unit 11 also converts power via the PCU 12 and supplies the power to the motor 13. The battery unit 11 is also charged via the PCU 12.

[0018] The PCU 12 performs bidirectional power conversion between the battery unit 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 unit 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 unit 11.

[0019] 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 unit 11 via the PCU 12 and stored in the battery pack 20.

[0020] 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 unit 11, and controls the PCU 12 to instruct the motor 13 to be driven and the battery unit 11 to be charged or discharged.

[0021] <Battery Unit> The battery unit 11 will now be described in detail. Fig. 2 is a block diagram showing the configuration of the battery unit 11. Fig. 3 is a diagram of the battery unit 11 when viewed from above (a plan view of the interior of the battery unit 11) showing a schematic arrangement of the various elements housed inside the battery unit 11, and Fig. 4 is a diagram of the battery unit 11 when viewed from the side (a side view of the interior of the battery unit 11) showing a schematic arrangement of the various elements housed inside the battery unit 11.

[0022] The battery unit 11 includes a battery pack 20, a battery monitoring system 100, and a housing 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, and wireless communication is performed between these devices. The battery monitoring devices 30 are sometimes called slave communication devices, and the battery control devices 40 are sometimes called master communication devices.

[0023] 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 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 the vehicle body frame or the like. In other words, the vehicle body frame may serve as a housing instead of the housing case 50.

[0024] <Battery Assembly> The battery assembly 20 includes multiple battery blocks 21 (sometimes referred to as battery stacks or battery modules). The multiple battery blocks 21 are connected in series and / or parallel to form the battery assembly 20. Each battery block 21 includes multiple battery cells 22 (shown by dashed lines in FIG. 3 ). Each battery cell 22 is formed from a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or the like. Note that lithium-ion secondary batteries are secondary batteries that use lithium as a charge carrier, and may include not only typical lithium-ion secondary batteries with liquid electrolytes but also so-called all-solid-state batteries that use solid electrolytes. The battery block 21 is formed by connecting the multiple battery cells 22 in series and / or parallel via bus bars (not shown). The battery block 21 may or may not be provided. The battery assembly 20 may be formed by connecting the multiple battery cells 22 in series and / or parallel. In this embodiment, the battery block 21 corresponds to the battery section.

[0025] <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 are mounted on a circuit board and housed in a case.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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."

[0030] 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.

[0031] 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.

[0032] 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.

[0033] <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.

[0034] 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 circuit board and housed in a case.

[0035] 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.

[0036] 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.

[0037] 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. Furthermore, the battery control MCU 41 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. Furthermore, the battery control MCU 41 controls relay switches and the like that switch the energized and de-energized states of the battery pack 20, the PCU 12, and the motor 13 based on the monitoring results. Furthermore, the battery control MCU 41 may 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] <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 a portion of the storage case 50 may be 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.

[0042] 3 and 4, the arrangement of the battery pack 20, the battery monitoring device 30, and the battery control device 40 will be briefly described. Below, the longitudinal direction of the housing case 50 will be referred to as the X direction, the lateral direction as the Y direction, and the up-down direction as the Z direction. The bottom surface of the housing case 50 is the mounting surface for the vehicle 10.

[0043] As shown in Fig. 3 , a plurality of battery blocks 21 that make up the battery pack 20 are arranged side by side in the X direction (longitudinal direction, left and right direction in Fig. 3 ) inside a roughly rectangular parallelepiped accommodating case 50. In each battery block 21, the battery cells 22 that make up the battery block 21 are arranged side by side so as to be stacked in the Y direction (transverse direction, up and down direction in Fig. 3 ) of the accommodating case 50.

[0044] A battery monitoring device 30 is disposed on a side surface of each battery block 21 and fixed thereto with screws or the like. In this embodiment, each battery monitoring device 30 is disposed in a spatial region formed between one side surface 52 of the accommodating case 50 in the Y direction (the lower side surface in FIG. 3 ) and one side surface of the battery block 21 in the Y direction. It can also be said that the battery monitoring device 30 is disposed in a spatial region formed between one side surface 52 of the accommodating case 50 in the Y direction and the assembled battery 20. In this embodiment, the one side surface 52 of the accommodating case 50 in the Y direction (the lower side surface in FIG. 3 ) is sometimes simply referred to as the second side surface 52, and the spatial region formed between the second side surface 52 of the accommodating case 50 and the assembled battery 20 is sometimes referred to as a second region 62.

[0045] 4, the battery monitoring devices 30 are arranged at approximately the same position (height) in the vertical direction (Z direction). Therefore, the child device side wireless antennas 33 are also arranged at approximately the same position in the Z direction. Therefore, the multiple battery monitoring devices 30 and their child device side wireless antennas 33 are arranged in a straight line along the X direction.

[0046] The battery control device 40 is disposed on one side in the X direction (longitudinal direction). The battery control device 40 of this embodiment is disposed in a spatial region formed between one side surface 51 of the housing case 50 in the X direction (the left side surface in FIG. 3 ) and one side surface of the battery block 21 in the X direction. It can also be said that the battery control device 40 is disposed in a spatial region formed between one side surface 51 of the housing case 50 in the X direction and the battery pack 20. In this embodiment, the one side surface 51 of the housing case 50 in the X direction (the left side surface in FIG. 3 ) is sometimes simply referred to as a first side surface 51, and the spatial region formed between the first side surface 51 of the housing case 50 and the battery pack 20 is sometimes referred to as a first region 61.

[0047] The battery control device 40 and the parent device side wireless antenna 43 are disposed approximately in the center of the housing case 50 in the Y direction. As shown in Fig. 4, the parent device side wireless antenna 43 is disposed at approximately the same height as the child device side wireless antenna 33 in the Z direction.

[0048] 3, when viewed from above, the battery control device 40 and the plurality of battery monitoring devices 30 are arranged in a generally L-shape along the first side surface 51 and the second side surface 52. Therefore, as shown by the arrows in FIG. 3, a main propagation path (or propagation path, the same applies hereinafter) 71 of radio waves used for wireless communication is generally L-shaped along the first side surface 51 and the second side surface 52.

[0049] The radio wave propagation path 71 is a space connecting the master-side wireless antenna 43 of the battery control device 40 and the slave-side wireless antenna 33 of the battery monitoring device 30, and is a path through which radio waves can propagate without being blocked. Therefore, it is desirable that the width of the propagation path 71 in a direction perpendicular to the direction of radio wave propagation be at least a predetermined size, for example, at least 1 / 2 the wavelength λ of the radio waves, over the entire area. In other words, the propagation path 71 is arranged so that radio wave shielding objects such as conductors cross the direction of radio wave propagation to prevent radio wave shielding. Incidentally, the propagation path 71 may be curved as long as the radio waves are not blocked.

[0050] For the above reasons, in the first embodiment, an approximately L-shaped propagation path 71 is illustrated as the main propagation path 71, but this is just one example, and in reality, there are propagation paths (not shown) through which radio waves are reflected by the side surfaces in the Y direction of the storage case 50, the top and bottom surfaces in the Z direction, the top and side surfaces of the battery block 21, etc., and reach the battery monitoring device 30 or the battery control device 40.

[0051] 3, a metal plate 80 serving as a conductive member is provided on the inside of a corner 53 between the first side surface 51 and the second side surface 52 of the accommodating case 50. The metal plate 80 will be described later.

[0052] 3 and 4 are merely examples of the arrangement of the battery pack 20, the battery monitoring device 30, and the battery control device 40, and may be changed as desired. Specific examples of such changes will be described later.

[0053] In order to ensure proper wireless communication, the battery monitoring system 100 is housed in a housing case 50 to suppress external influences such as external noise. However, even when the battery monitoring system 100 is housed in the housing case 50, communication quality may deteriorate depending on the shape of the housing space of the housing case 50 and the arrangement and shape of the battery cells 22 and battery blocks 21 inside the housing case 50.

[0054] For example, if there is a large difference in size between the first area 61 and the second area 62, and the area suddenly narrows when transitioning from the first area 61 to the second area 62, there is a problem that radio wave loss increases and communication quality deteriorates.

[0055] This radio wave loss will be described in more detail with reference to Figures 5 to 8. Figures 5 to 8 illustrate a comparative example that, unlike this embodiment, does not include the metal plate 80. Note that the configuration other than the metal plate 80 is the same as this embodiment.

[0056] When the dimensions of the first region 61 in the X direction, Y direction, and Z direction are sufficiently large compared to the wavelength of the radio waves, the radio waves passing through the first region 61 propagate through space in multiple modes. That is, in the first region 61, there are multiple propagation paths with significantly different paths, and not only do radio waves travel straight to the communication partner, but also radio waves that travel in a roundabout way by being reflected off the sides, etc., to propagate to the communication partner. In other words, the first region 61 provides an environment in which radio waves are easily diffused.

[0057] In FIG. 5, the dimensions of the first region 61 in the X direction, the Y direction, and the Z direction are each set to be larger than the wavelength of the radio waves. In such a case, the radio waves passing through the first region 61 propagate through space in multiple modes.

[0058] With this configuration, when the state of the electric field caused by the radio waves in the first region 61 is analyzed, it is found that the state of the electric field is not uniform, as shown in Figures 6 and 7. Note that Figure 6 shows the state of the electric field in the first region 61 and the second region 62 when viewed from above. The direction of the arrow indicates the direction of the electric field, and the thickness of the arrow indicates the strength of the electric field. Furthermore, Figure 7 shows the state of the electric field in the X-Z cross section of the first region 61. Figures 7(a) to (e) each show different positions in the Y direction. As shown in Figures 7(a) to (e), it can be seen that the state of the electric field in the X-Z cross section differs depending on the position in the Y direction.

[0059] On the other hand, if any of the dimensions of the second region 62 in the X direction, Y direction, or Z direction is not large enough relative to the wavelength of the radio waves, the radio waves passing through the second region 62 propagate through space in a single mode. That is, in the second region 62, the direction of travel of the radio waves is limited by the side and top surfaces, there is little difference in the propagation path, and all radio waves propagate in the same way toward the communication partner. In other words, the second region 62 provides an environment in which radio waves are less likely to diffuse.

[0060] 5, the dimension of the second region 62 in the Y direction is set to be smaller than half the wavelength of the radio wave (<λ / 2). In this case, the radio wave passing through the second region 62 propagates through space in single mode. Note that the dimension of the second region 62 in the Z direction is larger than the wavelength of the radio wave, and even if the dimension in the Y direction is small, there is no obstacle to the propagation of the radio wave in the X direction.

[0061] With this configuration, when the state of the electric field due to the radio waves in the second region 62 is analyzed, it is found that the state of the electric field is uniform, as shown in Figures 6 and 8. Figure 8 shows the state of the electric field in a cross section in the Y-Z direction of the second region 62. Figures 8(a) to 8(c) are each taken at different positions in the X direction, but as shown in Figures 8(a) to 8(c), it is found that the state of the electric field in the cross section in the Y-Z direction is the same even if the position in the X direction is different.

[0062] As described above, when the first region 61 and the second region 62 have significantly different sizes (areas) and the propagation patterns of radio waves differ between multimode and single mode, radio wave loss occurs. This is thought to be because radio waves transmitted (radiated) from the base-side wireless antenna 43 of the battery control device 40 are diffused in multiple directions in the first region 61 around the base-side wireless antenna 43, with only a portion of the waves propagating to the second region 62, while most of the radio waves are repeatedly reflected within the first region 61 and remain in the first region 61 or are delayed before propagating to the second region 62. In other words, if the entrance from the first region 61 to the second region 62 is narrow, it is thought that propagation to the second region 62 is difficult. Note that radio waves that enter the second region 62 propagate in single mode, and therefore radio wave loss after propagation to the second region 62 is thought to be small.

[0063] For the same reason, loss occurs when radio waves are propagated from the battery monitoring device 30 to the battery control device 40. That is, when the radio waves transmitted from the battery monitoring device 30 travel through the second region 62, they travel in a single mode, and it is thought that there is little loss of radio waves. However, when they propagate from the second region 62 to the first region 61, they travel in multiple modes within the first region 61, and so the radio waves are diffused, and fewer radio waves are propagated to the battery control device 40. That is, it is thought that loss occurs.

[0064] Therefore, the boundary 63 between the first region 61 and the second region 62 is configured so as to gradually narrow from the first region 61 toward the second region 62. The boundary 63 is the region between the first region 61 and the second region 62, and in this embodiment, it is the region between the metal plate 80 and the battery block 21 in the X direction. The region surrounded by a dashed line in FIG. 3 is the boundary 63. Furthermore, in the boundary 63, it is desirable that the opening portion connecting to the first region 61 is open over almost the entire first region 61. In this embodiment, the cross-sectional area of ​​the opening portion connecting to the first region 61 in the X-Z direction in the boundary 63 is approximately the same as the cross-sectional area of ​​the first region 61 in the X-Z direction. Similarly, it is desirable that the opening portion connecting to the second region 62 in the boundary 63 be open over almost the entire second region 62. In this embodiment, the cross-sectional area in the YZ direction of the opening portion of the boundary portion 63 that connects to the second region 62 is approximately the same as the cross-sectional area in the YZ direction of the second region 62 .

[0065] In the boundary portion 63, the cross-sectional area in a direction perpendicular to the propagation direction of the radio waves is configured to gradually narrow from the first region 61 toward the second region 62. In this embodiment, a metal plate 80 is provided inside the corner 53 of the housing case 50 so as to be inclined with respect to the first side surface 51 and the second side surface 52. The metal plate 80 is provided from the bottom surface to the top surface of the housing case 50 in the Z direction, with one end contacting the first side surface 51 in the X direction and the other end contacting the second side surface 52 in the Y direction. This metal plate 80 causes the boundary portion 63 to gradually narrow from the first region 61 toward the second region 62. In other words, the distance between the metal plate 80 and the side surface of the battery block 21 gradually shortens, and the area enclosed by the metal plate 80, the side surface of the battery block 21, the bottom surface of the housing case 50, and the top surface of the housing case 50 gradually decreases as it approaches the second region 62. The distance Lmin (see FIG. 9) when the metal plate 80 and the battery block 21 are closest to each other is equal to or less than half the wavelength of the radio wave.

[0066] In this embodiment, the direction of propagation of radio waves in the first region 61 is the direction of a straight line drawn from the parent-side wireless antenna 43 of the battery control device 40 to the boundary portion 63 so as to be the shortest distance. That is, in FIG. 3 , this is the Y direction.

[0067] The direction of propagation of radio waves in the second region 62 is the direction of a straight line drawn from the handset-side wireless antenna 33 of the battery monitoring device 30 toward the boundary portion 63 at the shortest distance. That is, in FIG. 3 , this direction is the X direction. The metal plate 80 is disposed inside the corner 53 so as to have an inclined surface with respect to the propagation direction of radio waves in the first region 61 (Y direction) and the propagation direction of radio waves in the second region 62 (X direction). Note that radio waves in the boundary portion 63 are reflected between the metal plate 80 and the side surface of the battery block 21 and propagate to the other region. Therefore, for convenience, in FIG. 3 , the propagation direction of radio waves in the boundary portion 63 is illustrated by a straight line connecting the end point of the line extending from the base-side wireless antenna 43 in the Y direction and the end point of the line extending from the handset-side wireless antenna 33 in the X direction.

[0068] The effect of providing such a metal plate 80 will now be described. By providing the metal plate 80 and configuring the boundary portion 63 so that it gradually narrows from the first region 61 toward the second region 62, radio waves that had been propagating in different directions in the first region 61 gradually align in the direction toward the second region 62. In other words, the radio waves that were diverging in the first region 61 align in the direction of propagation as they head toward the second region 62, and converge when they reach the second region 62. When the electric field is analyzed, it can be seen that the electric field eventually aligns in the direction and transitions to a single mode, as shown in FIG. 9 .

[0069] Next, the effect of providing the metal plate 80 will be described with reference to Fig. 10 using a comparative example. Fig. 10 shows the relationship between radio wave loss (reduction rate) and radio wave frequency. The dashed line in Fig. 10 shows the relationship between loss and frequency in the comparative example, and the solid line shows the relationship between loss and frequency in this embodiment. Note that the comparative example differs from this embodiment in that it does not provide the metal plate 80, but the other configurations are the same.

[0070] 10, in this embodiment, the loss can be reduced in most frequency bands compared to the comparative example. Moreover, in this embodiment, unlike the comparative example, the loss does not increase in a specific frequency band, and the loss is similar in most frequency bands.

[0071] The effects of this embodiment will be described below.

[0072] A boundary portion 63 between the first region 61 and the second region 62 is configured to gradually narrow from the first region 61 toward the second region 62. More specifically, at the boundary portion 63, the cross-sectional area in a direction perpendicular to the propagation direction of the radio waves gradually narrows from the first region 61 toward the second region 62. As a result, as shown in FIG. 9 , radio waves output from the battery control device 40 in the first region 61 and diffused in the first region 61 can be converged at the boundary portion 63 and propagated to the second region 62. As shown in FIG. 10 , this makes it possible to reduce radio wave loss when transmitting radio waves from the battery control device 40.

[0073] Similarly, radio waves output from the battery monitoring device 30 in the second region 62 are reflected by the metal plate 80 from the second region 62 toward the battery control device 40 in the first region 61 so that the propagation direction toward the battery control device 40 is more or less determined at the boundary portion 63, without being scattered randomly in multiple directions. This reduces radio wave loss.

[0074] A metal plate 80 is provided at the boundary portion 63 as a conductive member whose cross-sectional area in a direction perpendicular to the direction of propagation of the radio waves gradually narrows from the first region 61 toward the second region 62. This allows the shape of the region at the boundary portion 63 to be easily adjusted.

[0075] Furthermore, the metal plate 80 is a conductive plate having an inclined surface with respect to the direction of propagation of the radio waves, and therefore, by adjusting the inclination angle of the inclined surface, radio wave loss can be easily reduced.

[0076] Second Embodiment A second embodiment in which the configuration of the battery unit 11 in the first embodiment is partially modified will now be described.

[0077] In the first embodiment, it is known that radio wave loss increases depending on the frequency of the radio waves, as shown by the comparative example in Fig. 10. This is thought to be because the node position of the standing wave generated by the radio waves output from the battery control device 40 to the first region 61 coincides with the entrance to the second region 62, resulting in increased radio wave loss.

[0078] In other words, when the wavelength of the radio wave is λ and n is a natural number, it was discovered that when the length dimension of the first region 61 (including the boundary portion 63) in the direction of propagation of the radio wave is a value of n×λ / 2 or a value close to that value, the loss of the radio wave becomes large.

[0079] Therefore, in the second embodiment, the size of the first region 61 is adjusted so that the length dimension L1 of the first region 61 is a value other than n×λ / 2. More preferably, the size of the first region 61 is adjusted so that the length dimension of the first region 61 is a value close to (2n−1)×λ / 4 so that the antinode of the standing wave coincides with the entrance of the second region 62. In the second embodiment, for simplicity, the length dimension of the first region 61 is the length dimension of the accommodating case 50 in the Y direction.

[0080] In addition, in the second embodiment, assuming that the shape of the storage case 50 cannot be freely changed, a shielding plate 91 is provided as a radio wave blocking section made of a dielectric material on the opposite side of the second region 62 in the Y direction, as shown in Figure 11.

[0081] According to the second embodiment, the size of the first region 61 is adjusted so that the length dimension L1 of the first region 61 is a value other than n×λ / 2, thereby reducing radio wave loss. In particular, as shown by the solid line in Fig. 12, compared to the first embodiment (the solid line in Fig. 10), loss can be suppressed to the same degree in any frequency band.

[0082] Furthermore, the size of the first region 61 is adjusted by the shielding plate 91. This makes it possible to easily adjust the size of the first region 61 even when the shape of the accommodating case 50 cannot be changed.

[0083] Third Embodiment A third embodiment in which the configuration of the battery unit 11 in the first embodiment is partially modified will now be described.

[0084] 13 , in the third embodiment, a relay portion 92 is provided instead of the metal plate 80 as a relay member that collects radio waves from one region and emits the collected radio waves toward the other region. The relay portion 92 is made of a high-dielectric material and is provided at the boundary portion 63 between the first region 61 and the second region 62. The relay portion 92 is provided in the first region 61 so as to face the battery control device 40, and in the second region 62 so as to face the battery monitoring device 30.

[0085] The relay section 92 is formed in the first region 61 so as to protrude toward the parent device side wireless antenna 43 of the battery control device 40. The relay section 92 is formed in the second region 62 so as to protrude toward the child device side wireless antenna 33 of the battery monitoring device 30.

[0086] The relay unit 92 of the third embodiment collects radio waves from one area and emits the collected radio waves toward another area, thereby reducing radio wave loss.

[0087] (Modifications) The configuration of the battery unit 11 in the above embodiment may be partially modified. Modifications will be described below.

[0088] In the first and second embodiments, the metal plate 80 is configured as a plate having a flat surface, but may have a curved surface. For example, as shown in Fig. 14, the metal plate 80 may be a metal plate 81 having a curved surface that is convex toward the first region 61, or as shown in Fig. 15, the metal plate 82 may be a metal plate that is partially flat and partially curved.

[0089] In the first and second embodiments, a conductive member other than the metal plate 80 may be provided. For example, as shown in Fig. 16, the conductive member may be configured by a plurality of poles 83 (metal rods) made of a conductive material. The plurality of poles 83 are aligned at a predetermined interval so as to be oblique to the direction of propagation of the radio waves, and the intervals are less than the wavelength of the radio waves. This prevents radio waves from passing through the gaps between the poles 83, and similar to the metal plate 80, it is possible to converge the radio waves and reduce loss.

[0090] In the first and second embodiments, the shape of the corners 53 of the housing 50 may be changed without providing the metal plates 80 to 82. For example, as shown in Fig. 17, the corners 53 may be recessed, and curved surfaces 85 similar to the metal plates 80 to 82 may be provided on the inside of the corners 53. Note that the surface is not limited to the curved surface 85, and may be flat.

[0091] In the second embodiment, the shielding plate 91 is not limited to a metal plate member, and may be made of a high-permittivity material.

[0092] In the above embodiment, the battery monitoring device 30 may be fixed to the upper surface of the battery block 21. For example, as shown in FIG. 18 , the battery monitoring device 30 is disposed on the upper surface of each battery block 21. That is, as shown in FIG. 19 , each battery monitoring device 30 is disposed in a spatial region formed between the upper surface 54 of the housing case 50 and the upper surface of the battery block 21. In this modification, the spatial region formed between the upper surface 54 of the housing case 50 and the battery pack 20 may be referred to as a second region 162. Like the second region 62 in the first embodiment, the second region 162 in this modification has any one of its dimensions in the X direction, Y direction, or Z direction that is not large enough to accommodate the wavelength of the radio wave, and the radio wave passing through the second region 162 propagates through space in a single mode. In FIG. 19 , the Z direction dimension of the second region 62 is set to be smaller than half the wavelength of the radio wave (<λ / 2), and the radio wave propagates in a single mode.

[0093] Furthermore, the battery monitoring device 30 is disposed in the center in the Y direction on the top surface of each battery block 21. As a result, the battery monitoring device 30 and the slave-side wireless antenna 33 are aligned in a straight line in the X direction.

[0094] Meanwhile, as in the first embodiment, the battery control device 40 is disposed in a first region 61 formed between the first side surface 51 of the casing 50 and the battery pack 20. The parent-side wireless antenna 43 is disposed approximately in the center of the casing 50 in the Y direction. Therefore, as shown in Fig. 18 , the parent-side wireless antenna 43 is disposed in a substantially solid line with the child-side wireless antenna 33 in the X direction.

[0095] 19 , when viewed from the side, the battery control device 40 and the plurality of battery monitoring devices 30 are arranged in a generally L-shape along the first side surface 51 and the top surface 54. Therefore, as shown by the arrows in FIG. 19 , a main propagation path 171 of radio waves used for wireless communication is generally L-shaped along the first side surface 51 and the top surface 54.

[0096] As shown in FIGS. 18 and 19, a metal plate 180 serving as a conductive member is provided on the inside of a corner 55 between the first side surface 51 and the top surface 54 of the accommodating case 50 .

[0097] As in the first embodiment, this metal plate 180 forms a boundary portion 163 between the first region 61 and the second region 162 so that the boundary portion 163 gradually narrows from the first region 61 toward the second region 162 .

[0098] More specifically, in this modification, a metal plate 180 is provided inside a corner 55 of the housing case 50 so as to be inclined with respect to the first side surface 51 and the top surface 54. The metal plate 180 is provided from one end of the housing case 50 to the other in the Y direction, with one end abutting the first side surface 51 in the X direction and the other end abutting the top surface 54 in the Z direction. Due to this metal plate 180, the boundary portion 163 gradually narrows from the first region 61 toward the second region 62.

[0099] As a result, this modification can achieve the same effects as the first embodiment. Furthermore, it is possible to reduce the width dimension in the Y direction compared to the first embodiment.

[0100] In the above embodiment and modified examples, the boundary portions 63, 163 between the first region 61 and the second region 62, 162 are gradually narrowed from the first region 61 toward the second region 62, 162. As another example, the boundary portions 63, 163 may be narrowed in stages (in a stepped manner). In this case, for example, as shown in FIG. 20 , a metal plate 280 formed in a stepped manner may be provided.

[0101] Below, the technical ideas that can be derived from the above-described embodiments and modifications will be additionally described.

[0102] [Configuration 1] A battery unit (11) comprising a battery section (20, 21, 22), a slave communication device (30) that detects battery information and transmits it via wireless communication, a master communication device (40) that receives battery information from the slave communication device via wireless communication, and a conductive housing (50) that houses them, wherein within the housing, a first region (61) in which either the slave communication device or the master communication device is disposed is wider than a second region (62) in which the other is disposed, and a boundary portion (63) between the first region and the second region is configured to narrow from the first region toward the second region.

[0103] [Configuration 2] The battery unit according to Configuration 1, wherein the boundary portion is configured such that a cross-sectional area in a direction perpendicular to a propagation direction of radio waves used for the wireless communication narrows from the first region toward the second region.

[0104] [Configuration 3] The battery unit according to Configuration 1 or 2, wherein the boundary portion is provided with a conductive member (80, 81, 82, 83) that narrows a cross-sectional area in a direction perpendicular to a direction of propagation of radio waves used for the wireless communication from the first region toward the second region.

[0105] [Configuration 4] The battery unit according to any one of configurations 1 to 3, wherein a conductive member is provided in the boundary portion, the conductive member narrowing a cross-sectional area in a direction perpendicular to the propagation direction of radio waves used for the wireless communication from the first region toward the second region, and the conductive member is a conductive plate (80) having an inclined surface with respect to the propagation direction of the radio waves in the first region or the second region.

[0106] [Configuration 5] A battery unit according to any one of configurations 1 to 3, wherein a conductive member is provided in the boundary portion, the conductive member narrowing a cross-sectional area in a direction perpendicular to the direction of propagation of radio waves used for the wireless communication from the first region toward the second region, the conductive member being composed of a plurality of poles (83) formed of a conductive material, the plurality of poles being aligned at a predetermined interval so as to be oblique to the direction of propagation of the radio waves, and the interval being less than the wavelength of the radio waves.

[0107] [Configuration 6] The battery unit according to Configuration 1 or 2, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery unit, the second region is a spatial region formed between a second surface (52) of either the inner side surface or the top surface of the housing and the battery unit, the first surface and the second surface are in contact via a corner (53) of the housing, and a curved surface (85) or a slope is provided on the inside of the corner.

[0108] [Configuration 7] A battery unit (11) comprising a battery section (20, 21, 22), a slave communication device (30) that detects battery information and transmits it via wireless communication, a master communication device (40) that receives battery information from the slave communication device via wireless communication, and a conductive housing (50) that houses them, wherein within the housing, a first region (61) in which either the slave communication device or the master communication device is disposed is larger than a second region (62) in which the other is disposed, and a relay member (92) is disposed at a boundary portion (63) between the first region and the second region that collects radio waves from one region and emits the collected radio waves toward the other region.

[0109] [Configuration 8] The battery unit according to any one of Configurations 1 to 7, wherein, when the wavelength of the radio wave used for the wireless communication is λ and n is a natural number, the length dimension of the first region in the propagation direction of the radio wave is a dimension other than n×λ / 2.

[0110] [Configuration 9] The battery unit according to Configuration 8, wherein the first region is provided with a radio wave blocking section (91) made of a dielectric material on the opposite side of the second region in the direction of radio wave propagation so that the length dimension of the first region is a dimension other than n×λ / 2.

[0111] [Configuration 10] The battery unit according to any one of configurations 1 to 9, wherein a width dimension of the first region in a direction perpendicular to the propagation direction of radio waves used for the wireless communication is equal to or greater than the wavelength of the radio waves, and a width dimension of the second region in a direction perpendicular to the propagation direction of the radio waves is less than the wavelength of the radio waves.

[0112] [Configuration 11] The battery unit according to any one of configurations 1 to 10, wherein radio waves used for the wireless communication propagate in a multimode in the first region, and the radio waves propagate in a single mode in the second region.

[0113] [Configuration 12] A battery unit according to any one of configurations 1 to 11, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery unit, the second region is a spatial region formed between a second surface (52) of either the inner side surface or the top surface of the housing and the battery unit, the first surface and the second surface are in contact via a corner (53) of the housing, and the inside of the corner is the boundary portion (63).

[0114] [Configuration 13] The battery unit according to any one of configurations 3 to 5, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery unit, the second region is a spatial region formed between a second surface (52) of either the inner side surface or the top surface of the housing and the battery unit, the first surface and the second surface are in contact via a corner (53) of the housing, and the conductive member (80, 81, 82, 83) is arranged inside the corner.

[0115] 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 battery unit (11) comprising a battery section (20, 21, 22), a slave communication device (30) that detects battery information and transmits it via wireless communication, a master communication device (40) that receives battery information from the slave communication device via wireless communication, and a conductive housing (50) that houses them, wherein within the housing, a first region (61) in which either the slave communication device or the master communication device is disposed is wider than a second region (62, 162) in which the other is disposed, and a boundary portion (63, 163) between the first region and the second region is configured to narrow from the first region toward the second region.

2. A battery unit as described in claim 1, wherein the cross-sectional area of ​​the boundary portion in a direction perpendicular to the direction of propagation of the radio waves used for the wireless communication is configured to narrow from the first region toward the second region.

3. A battery unit as described in claim 1, wherein the boundary portion is provided with a conductive member (80, 81, 82, 83, 180) that narrows the cross-sectional area in a direction perpendicular to the direction of propagation of the radio waves used for the wireless communication from the first region toward the second region.

4. A battery unit as described in claim 1, wherein a conductive member is provided in the boundary portion, which narrows the cross-sectional area in a direction perpendicular to the direction of propagation of the radio waves used for the wireless communication from the first region toward the second region, and the conductive member is a conductive plate (80, 180) having an inclined surface with respect to the direction of propagation of the radio waves in the first region or the second region.

5. A battery unit as described in claim 1, wherein a conductive member is provided in the boundary portion, which narrows the cross-sectional area in a direction perpendicular to the direction of propagation of the radio waves used for the wireless communication from the first region toward the second region, and the conductive member is composed of a plurality of poles (83) formed of a conductive material, and the plurality of poles are aligned at a predetermined interval so as to be oblique to the direction of propagation of the radio waves, and the interval is less than the wavelength of the radio waves.

6. A battery unit as described in claim 1, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery unit, the second region is a spatial region formed between a second surface (52, 54) of either the inner side surface or the top surface of the housing and the battery unit, the first surface and the second surface are in contact via corners (53, 55) of the housing, and a curved surface (85) or a slope is provided on the inside of the corner.

7. A battery unit (11) comprising a battery section (20, 21, 22), a slave communication device (30) that detects battery information and transmits it via wireless communication, a master communication device (40) that receives battery information from the slave communication device via wireless communication, and a conductive housing (50) that houses them, wherein within the housing, a first area (61) in which either the slave communication device or the master communication device is disposed is larger than a second area (62) in which the other is disposed, and a relay member (92) is disposed at a boundary portion (63) between the first and second areas that collects radio waves from one area and emits the collected radio waves toward the other area.

8. A battery unit according to any one of claims 1 to 7, wherein, when the wavelength of the radio waves used for the wireless communication is λ and n is a natural number, the length dimension of the first region in the direction of propagation of the radio waves is a dimension other than n × λ / 2.

9. A battery unit as described in claim 8, wherein the first region is provided with a radio wave blocking section (91) made of a dielectric material on the opposite side of the second region in the direction of radio wave propagation so that the length dimension of the first region is a dimension other than n×λ / 2.

10. A battery unit as described in any one of claims 1 to 7, wherein the width dimension of the first region in a direction perpendicular to the direction of propagation of the radio waves used for wireless communication is equal to or greater than the wavelength of the radio waves, and the width dimension of the second region in a direction perpendicular to the direction of propagation of the radio waves is less than the wavelength of the radio waves.

11. A battery unit according to any one of claims 1 to 7, wherein radio waves used for the wireless communication propagate in multimode in the first area, while the radio waves propagate in single mode in the second area.

12. A battery unit as described in any one of claims 1 to 7, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery section, the second region is a spatial region formed between a second surface (52, 54) of either the inner side surface or the top surface of the housing and the battery section, the first surface and the second surface are in contact via a corner (53, 55) of the housing, and the inside of the corner is the boundary portion (63, 163).

13. A battery unit as set forth in any one of claims 3 to 5, wherein the first region is a spatial region formed between a first surface (51) of either the inner side surface or the top surface of the housing and the battery section, the second region is a spatial region formed between a second surface (52, 54) of either the inner side surface or the top surface of the housing and the battery section, the first surface and the second surface are in contact via corners (53, 55) of the housing, and the conductive members (80, 81, 82, 83, 180) are arranged inside the corners.

Images