Battery Module

Abstract

To provide a battery module in which interference with wireless communication is suppressed. [Solution] First end faces (50a) of multiple battery cells (50) and an inner top face (131a) of a top wall (131) face each other while being spaced apart in the z direction. A negative electrode terminal (51) and a positive electrode terminal (52) are formed on the first end face and spaced apart in the x direction. A bus bar (70) is connected to these terminals. A waveguide path (160) is defined between the bus bars spaced apart in the x direction and between the first end face and the inner top face, which are spaced apart in the z direction. An individual communication unit (110) that wirelessly communicates with an integrated monitoring unit (30) is provided in this waveguide path. The length of the waveguide path in the x direction is longer than half the wavelength of the wireless signal and shorter than the same wavelength. The length of the waveguide path in the z direction is longer than the length in the x direction.

Description

[Technical field]

[0001] The disclosure described herein relates to a battery module including a plurality of assembled batteries. [Background technology]

[0002] As disclosed in Patent Document 1, a power supply system including a battery and a battery monitoring system is known. The battery monitoring system includes a plurality of battery monitoring devices and a battery ECU. The plurality of battery monitoring devices and the battery ECU communicate wirelessly with each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-61303 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the power supply system described in Patent Document 1, Battery There is a risk that wireless communication between the monitoring device and the battery ECU may be interrupted.

[0005] Therefore, an object of the disclosure described in this specification is to provide a battery module in which interference with wireless communication is suppressed. [Means for solving the problem]

[0007] One disclosure relates to a battery pack (20); a plurality of individual detection units (90) that individually detect a physical quantity of each of the plurality of assembled batteries; a plurality of individual communication units (110) that output the detection results of the respective plurality of individual detection units as wireless signals; A monitoring unit (30) that wirelessly communicates with each of the plurality of individual communication units; an individual waveguide (180) in which an individual communication unit is housed in an internal waveguide path (160); The battery pack includes an electromagnetic reflection housing (40) that houses the plurality of battery packs, the plurality of individual detection units, the plurality of individual communication units, the monitoring unit, and the individual waveguides in a storage space. Another disclosed embodiment includes a battery pack (20); an individual communication unit (110) that outputs a detection result of a physical quantity of the battery pack by a wireless signal; A monitoring unit (30) that wirelessly communicates with the individual communication unit; an individual waveguide (180) in which an individual communication unit is housed in an internal waveguide path (160); The battery pack includes a housing (40) that houses the battery pack, the individual communication unit, the monitoring unit, and the individual waveguide in a housing space.

[0009] According to the present disclosure, an individual communication unit This prevents the (110) from having difficulty receiving the wireless signal output from the monitoring unit (30), thereby preventing wireless communication from being interrupted.

[0010] It should be noted that the reference numbers in parentheses above merely indicate the corresponding relationship with the configurations described in the embodiments described below, and do not in any way limit the technical scope. [Brief description of the drawings]

[0011] [Figure 1] FIG. 2 is a schematic diagram for explaining a battery module and a battery ECU. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a cross-sectional view for explaining a waveguide path in the first embodiment. [Figure 4] FIG. 11 is a cross-sectional view for explaining a waveguide path according to a second embodiment. [Diagram 5] FIG. 11 is a cross-sectional view for explaining a waveguide path according to a third embodiment. [Figure 6] FIG. 11 is a cross-sectional view for explaining a waveguide path according to a third embodiment. [Figure 7] FIG. 13 is a cross-sectional view for explaining a waveguide path according to a fourth embodiment. [Figure 8] FIG. 11 is a cross-sectional view for explaining a modified example of the battery module. [Figure 9] FIG. 11 is a cross-sectional view for explaining a modified example of the battery module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments and modifications of the present disclosure will be described with reference to the drawings. Each of these embodiments and modifications includes a common element. When this common element is described in one embodiment, the description of this common element will be omitted in other embodiments and modifications. The common element will be given the same reference numeral in each of the multiple embodiments and modifications.

[0013] (First embodiment) The battery module according to this embodiment will be described with reference to Figures 1 to 3. The battery module according to this embodiment is applied to vehicles such as electric vehicles and plug-in hybrid vehicles.

[0014] In the following, the three mutually orthogonal directions are referred to as the x-direction, y-direction, and z-direction. Note that the directions are omitted in the drawings. The x-direction corresponds to the horizontal direction. The y-direction corresponds to the vertical direction. The z-direction corresponds to the height direction.

[0015] <Car battery> FIG 1 shows a battery module 10. The battery module 10 constitutes an on-board power supply. The battery module 10 serves to supply power to an electrical load of the vehicle. Of course, the on-board power supply may be constituted by electrically connecting a plurality of battery modules 10 in series or parallel.

[0016] The temperature of the battery module 10 is adjusted by wind supplied from a fan mounted on the vehicle, or by a cooling liquid circulating inside the vehicle. This prevents excessive temperature changes in the battery module 10.

[0017] The battery module 10 can be arranged, for example, in the space under the front seats of the vehicle, the space under the rear seats, or the space between the rear seats and the trunk.

[0018] <Battery module> 1, the battery module 10 includes a plurality of assembled batteries 20, an integrated monitoring unit 30, and a case 40. The assembled batteries 20 and the integrated monitoring unit 30 are housed in a storage space of the case 40.

[0019] <Battery pack> Each of the multiple assembled batteries 20 has multiple battery cells 50, a battery case 60, a bus bar 70, and an information acquisition unit 80. The battery case 60 houses the multiple battery cells 50. The bus bar 70 electrically connects the multiple battery cells 50. The information acquisition unit 80 acquires physical quantities of the multiple battery cells 50 and outputs them to the integrated monitoring unit 30. The information acquisition unit 80 also performs an equalization process, which will be described later.

[0020] The battery cell 50 is a secondary battery that generates an electromotive force through a chemical reaction. For example, a lithium ion secondary battery can be used as this secondary battery.

[0021] The battery cell 50 has a power generating element and a metal case that houses the power generating element. As shown in Figures 2 and 3, the metal case has a flat plate shape with a small thickness in the y direction. The metal case has a first end face 50a and a second end face 50b aligned in the z direction, a first main surface 50c and a second main surface 50d aligned in the y direction, and a first side surface 50e and a second side surface 50f aligned in the x direction. Of the six faces of the metal case, the first main surface 50c and the second main surface 50d have larger areas than the other four faces.

[0022] A negative electrode terminal 51 and a positive electrode terminal 52 are formed on a first end surface 50a of the metal case. The negative electrode terminal 51 and the positive electrode terminal 52 are arranged side by side and spaced apart in the x direction. The negative electrode terminal 51 is located on the first side surface 50e side. The positive electrode terminal 52 is located on the second side surface 50f side. The first end surface 50a corresponds to the electrode formation surface.

[0023] <Battery case> 2 and 3, the battery case 60 has a support wall 61 and a peripheral wall 62. The support wall 61 and the peripheral wall 62 are integrally connected. The support wall 61 and the peripheral wall 62 are each made of an insulating resin material. Note that FIG. 3 shows a cross-sectional shape of the battery pack 20 taken along line III-III shown in FIG. 2.

[0024] The support wall 61 has a flat shape with a small thickness in the z direction. The support wall 61 has an inner support surface 61a and an outer support surface 61b on the rear side thereof, which are spaced apart from each other in the z direction.

[0025] The peripheral wall 62 stands upright in the z direction from the inner support surface 61a. The peripheral wall 62 extends along the edge of the inner support surface 61a and forms an annular shape in the circumferential direction around the z direction.

[0026] Specifically, the peripheral wall 62 has a first end wall 63 and a second end wall 64 that are spaced apart in the y direction, and a first connecting wall 65 and a second connecting wall 66 that are spaced apart in the x direction. The first end wall 63, the first connecting wall 65, the second end wall 64, and the second connecting wall 66 are connected in this order in the circumferential direction around the z direction. This forms the peripheral wall 62 in an annular shape in the circumferential direction around the x direction. The space above the inner support surface 61a is surrounded by the peripheral wall 62. Multiple battery cells 50 are stored in this storage space.

[0027] The second end surface 50b side of each of the multiple battery cells 50 is housed in the storage space of the battery case 60. The first end surface 50a side of each of the multiple battery cells 50 is located outside the storage space of the battery case 60. Therefore, the negative electrode terminal 51 and the positive electrode terminal 52 of each of the multiple battery cells 50 are located outside the storage space of the battery case 60.

[0028] The multiple battery cells 50 are lined up in the y direction between a first end wall 63 and a second end wall 64 of the battery case 60. Although not shown, the battery case 60 has a partition wall provided between any two battery cells 50 lined up adjacent to each other in the y direction. This partition wall sets the y-direction separation distance between any two battery cells 50 lined up adjacent to each other in the y direction to w1. This first separation distance w1 is narrower than the thickness of the battery cells 50 in the y direction.

[0029] Any two battery cells 50 adjacent to each other in the y direction are arranged such that their first principal surfaces 50c or their second principal surfaces 50d face each other. Due to this facing arrangement, the negative electrode terminal 51 of one of the two battery cells 50 adjacent to each other in the y direction and the positive electrode terminal 52 of the other battery cell are aligned in the y direction.

[0030] The distance in the y direction between the negative electrode terminal 51 of one of any two battery cells 50 and the positive electrode terminal 52 of the other of the two battery cells 50 that are adjacent to each other in the y direction is w2. This second distance w2 is approximately the same as or shorter than the thickness of the battery cell 50 in the y direction.

[0031] 2, a plurality of negative electrode terminals 51 and positive electrode terminals 52 are arranged in alternating rows on each of the first connecting wall 65 side and the second connecting wall 66 side of the battery case 60. For ease of notation, hereinafter, an electrode terminal group including a plurality of negative electrode terminals 51 and positive electrode terminals 52 arranged in a row on the first connecting wall 65 side is referred to as a first electrode terminal group. An electrode terminal group including a plurality of negative electrode terminals 51 and positive electrode terminals 52 arranged in a row on the second connecting wall 66 side is referred to as a second electrode terminal group.

[0032] The negative electrode terminal 51 and the positive electrode terminal 52 included in the first electrode terminal group and the second electrode terminal group are electrically connected by a bus bar 70 shown in Figures 2 and 3. Through this electrical connection, the multiple battery cells 50 are electrically connected in series to form one battery stack.

[0033] Although not shown, the battery stacks included in each battery pack 20 are electrically connected in series by wires or the like. A power line is connected to each of the battery pack 20 with the highest potential and the battery pack 20 with the lowest potential. The battery stacks included in each battery pack 20 may be electrically connected in parallel.

[0034] <Busbar> The bus bar 70 is made of a conductive metal material such as copper or aluminum. The bus bar 70 has two terminal conductive portions 71 that are integrally connected and aligned in the y direction. The terminal conductive portion 71 has a thin flat plate shape with a small thickness in the z direction. The thickness of the terminal conductive portion 71 is determined so as to prevent the laser from causing a temperature rise that would change the performance of the battery cell 50 when the terminal conductive portion 71 and the electrode terminal of the battery cell 50 are laser-welded.

[0035] A conductive extension 72 extends from one of two terminal conductive portions 71 included in the bus bar 70. The conductive extension 72 extends from the terminal conductive portion 71 in a manner separated from a current path between a connection portion of one of the two terminal conductive portions 71 with the negative electrode terminal 51 and a connection portion of the other terminal conductive portion 71 with the positive electrode terminal 52. This makes it difficult for a current to flow through the conductive extension 72. A voltage sensor 90a, which will be described later, is electrically connected to this conductive extension 72.

[0036] 2, a plurality of bus bars 70 are arranged at intervals in the y direction. The interval in the y direction between two bus bars 70 arranged adjacent to each other in the y direction is w3. This third interval w3 is shorter than the second interval w2.

[0037] <Information acquisition section> The information acquisition unit 80 has a plurality of sensors 90 that detect the physical quantities of each of the plurality of battery cells 50, an individual monitoring unit 100 to which the detection results of the plurality of sensors 90 are input, and an individual communication unit 110 that inputs and outputs wireless signals. The sensor 90 is provided on the detection target. The individual monitoring unit 100 and the individual communication unit 110 are each mounted on a wiring board 81. As shown in FIG. 2, this wiring board 81 is provided on a first end surface 50a of the plurality of battery cells 50.

[0038] The multiple sensors 90 include a voltage sensor, a temperature sensor, and a current sensor. The voltage sensor detects the output voltage of each of the multiple battery cells 50. The temperature sensor detects the temperature of at least one of the multiple battery cells 50. The current sensor detects a current that flows commonly to each of the multiple battery cells 50 electrically connected in series. The sensors 90 correspond to individual detection units.

[0039] 2 and 3, only a voltage sensor 90a is shown as a representative of the multiple types of sensors that detect the different physical quantities described above. The voltage sensor 90a has a voltage detection wire 91, a voltage detection terminal 92, a detection screw 93, and a nut 94.

[0040] The voltage detection wiring 91 is an insulated electric wire in which a conductor is covered with an insulating coating. A voltage detection terminal 92 is connected to one end of the voltage detection wiring 91. The other end of the voltage detection wiring 91 is electrically connected to the individual monitoring unit 100 via a connector or the like mounted on the wiring board 81. In Fig. 2, in order to avoid complication of notation, only one end side of the voltage detection wiring 91 is shown.

[0041] A through hole opening in the z direction is formed in each of the voltage detection terminal 92 and the conductive extension 72. The voltage detection terminal 92 and the conductive extension 72 are arranged facing each other with these two through holes communicating in the z direction. The shaft portion of a detection screw 93 is passed through these two through holes, and a nut 94 is fastened to this shaft portion.

[0042] The shaft side of the head of the detection screw 93 contacts the upper surface of the voltage detection terminal 92, and the nut 94 contacts the lower surface of the conductive extension 72. The voltage detection terminal 92 and the conductive extension 72 are clamped between the head of the detection screw 93 and the nut 94. As a result, each of the multiple voltage detection terminals 92 and each of the multiple conductive extensions 72 are individually and electrically connected to each other.

[0043] The individual monitoring unit 100 receives the detection results of the multiple sensors 90. The individual monitoring unit 100 generates a monitoring signal to which an identification code is added to identify which of the multiple battery packs 20 the signal is output from, along with the detection results of the multiple sensors 90. This monitoring signal is input to the individual communication unit 110.

[0044] The individual communication unit 110 converts the input monitoring signal into a wireless signal. This wireless signal is output from the individual communication unit 110 to the storage space of the case 40. This wireless signal is received by the integrated monitoring unit 30. Wireless communication is performed between the individual communication unit 110 and the integrated monitoring unit 30.

[0045] Radio waves in a frequency band of 3 kHz to 3 THz are used as the wireless signals output from the individual communication unit 110 and the integrated monitoring unit 30. In particular, ultra-high frequency waves in a frequency band of 300 MHz to 3 GHz can be used as these wireless signals.

[0046] The frequency and wavelength of the radio signals output from the individual communication unit 110 and the integrated monitoring unit 30 are constant. The frequency (wavelength) of the radio signal is determined according to the shape of the battery cell 50 employed, etc. For ease of notation, the frequency of the radio signal will be referred to as the fundamental frequency f, and the wavelength of the radio signal will be referred to as the fundamental wavelength λ below.

[0047] <Integrated Monitoring Department> The integrated monitoring unit 30 receives wireless signals output from each of the multiple battery packs 20. The integrated monitoring unit 30 converts the wireless signals into digital signals. The integrated monitoring unit 30 then outputs the digital signals to the battery ECU 200. The integrated monitoring unit 30 corresponds to a monitoring unit.

[0048] The battery ECU 200 calculates the SOC of the battery module 10 based on the input digital signal. SOC is an abbreviation for state of charge. The battery ECU 200 then determines whether to charge or discharge the battery module 10 based on the detected SOC and on-vehicle information input from other on-vehicle ECUs, on-vehicle sensors, etc.

[0049] Furthermore, the battery ECU 200 calculates the SOC of each of the plurality of battery cells 50 included in each of the plurality of battery packs 20. Then, the battery ECU 200 determines whether or not to perform equalization processing of the SOC of each of the plurality of battery cells 50. The battery ECU 200 outputs an instruction signal to the integrated monitoring unit 30 based on the determination of the equalization processing.

[0050] The integrated monitoring unit 30 outputs the input instruction signal as a wireless signal to the storage space of the case 40. This instruction signal contains the above-mentioned identification code, so that only the individual monitoring unit 100 among the multiple individual monitoring units 100 that corresponds to the identification code contained in the wireless signal receives this wireless signal.

[0051] The individual monitoring unit 100 includes a switch element for individually charging and discharging each of the multiple battery cells 50. The individual monitoring unit 100 controls the opening and closing of the switch element based on an input instruction signal, thereby electrically connecting specific battery cells 50 among the multiple battery cells 50.

[0052] A current flows from a battery cell 50 with a relatively high SOC to a battery cell 50 with a relatively low SOC among the multiple electrically connected battery cells 50. As a result, the SOCs of the multiple battery cells 50 are equalized.

[0053] The SOC of each of the multiple battery cells 50 included in one battery pack 20 may be calculated by an individual monitoring unit 100 included in the battery pack 20. The individual monitoring unit 100 may then determine whether or not to perform equalization processing of the SOC of each of the multiple battery cells 50.

[0054] <Case> The case 40 has a housing 120 having an opening, and a cover 130 fixed to the housing 120 in a manner that closes the opening.

[0055] The housing 120 has a bottom wall 121 and a side wall 122 standing in an annular shape from the bottom wall 121. The bottom wall 121 has a flat shape with a small thickness in the z direction. The side wall 122 stands in the z direction from an inner bottom surface 121a of the bottom wall 121. The side wall 122 forms an annular shape in the circumferential direction around the z direction. An opening is defined at the tip side of the side wall 122.

[0056] The cover 130 has a top wall 131 and an annular edge wall 132 standing up from the top wall 131. The top wall 131 has a flat shape with a small thickness in the z direction. The edge wall 132 stands up from an inner top surface 131a of the top wall 131 in the z direction.

[0057] The cover 130 is provided on the housing 120 in such a manner that the inner top surface 131a of the top wall 131 and the inner bottom surface 121a of the bottom wall 121 are aligned while being spaced apart in the z direction. The tip side of the edge wall 132 and the tip side of the bottom wall 121 are connected to each other. This forms the storage space of the case 40.

[0058] A hole (not shown) is formed in the housing 120 to communicate the storage space formed by the housing 120 and the cover 130 with the outside space (external space). The hole can be used for ventilation of the case 40, for taking out power lines, for taking out signal lines, etc.

[0059] <Wireless communication> As described above, wireless communication is performed between the information acquisition units 80 of each of the multiple battery packs 20 and one integrated monitoring unit 30 in the storage space of the case 40. In order to prevent the battery module 10 from becoming a source of electromagnetic noise, it is necessary to prevent the wireless signals used in this wireless communication from leaking out of the storage space of the case 40. Conversely, in order to prevent this wireless communication from being disrupted, it is necessary to prevent electromagnetic noise from entering the storage space of the case 40.

[0060] In order to solve this problem, each of the housing 120 and the cover 130 has the ability to reflect electromagnetic waves. The case 40 including the housing 120 and the cover 130 corresponds to an electromagnetic reflection housing. In order to have such a ability to reflect electromagnetic waves, the housing 120 and the cover 130 are made of the materials shown below as examples.

[0061] For example, the housing 120 and the cover 130 include a conductive material such as metal. The housing 120 and the cover 130 include a resin material and a conductive material covering the surface. The housing 120 and the cover 130 include a resin material and a conductive material embedded therein. The housing 120 and the cover 130 include carbon fiber.

[0062] <Standing wave> In this way, wireless signals are output from the individual communication unit 110 and the integrated monitoring unit 30 to the storage space formed by the housing 120 and the cover 130, which have the ability to reflect electromagnetic waves. The wireless signals are repeatedly reflected by the inner surfaces of the housing 120 and the cover 130 that define the storage space.

[0063] This repeated reflection generates multiple high-order electromagnetic waves in the storage space, each with a frequency that is an integer multiple of the frequency of the wireless signal (fundamental frequency f). These multiple high-order electromagnetic waves with different frequencies are superimposed in the storage space. This generates standing waves in the storage space. Places in the storage space where the electromagnetic waves tend to be strengthened and places where they tend to be weakened are generated in the storage space. As a result, it may become difficult to receive wireless signals in the storage space. Note that the above integer multiple refers to two or more times.

[0064] <Waveguide paths and waveguides> In order to solve this problem, a waveguide path 160 is configured in each of the multiple battery packs 20 housed in the case 40. An individual communication unit 110 is provided in this waveguide path 160. The battery module 10 has a waveguide 170 that houses the integrated monitoring unit 30. The waveguide path 160 is shown by a dashed line in FIG.

[0065] <Waveguide path> For example, as shown in FIG. 3, the battery pack 20 is stored in the storage space of the case 40 with the first end surface 50a of each of the multiple battery cells 50 positioned on the lid 130 side.

[0066] Due to this arrangement, the first end surface 50a of each of the multiple battery cells 50 included in the battery pack 20 and the inner top surface 131a of the top wall 131 of the lid body 130 are arranged to face each other in the z direction. At the same time, the bus bar 70 connected to the electrode terminals of each of the multiple battery cells 50 and the head of the detection screw 93 of the voltage sensor 90a connected to this bus bar 70 are arranged to face each other in the z direction with the inner top surface 131a.

[0067] As described above, the first electrode terminal group is configured by arranging a plurality of negative electrode terminals 51 and positive electrode terminals 52 in a row on the first connecting wall 65 side. The bus bar 70 is connected to the negative electrode terminals 51 and positive electrode terminals 52 included in this first electrode terminal group. A conductive portion of the voltage sensor 90a is connected to each of the plurality of bus bars 70. Although not shown in FIG. 3, a voltage detection wiring 91 including a conductor is provided above the plurality of bus bars 70. The bus bar 70 connecting the negative electrode terminals 51 and positive electrode terminals 52 included in the first electrode terminal group corresponds to a first terminal connection portion.

[0068] Similarly, a second electrode terminal group is formed by arranging a plurality of negative electrode terminals 51 and positive electrode terminals 52 in a row on the second connecting wall 66 side. A bus bar 70 is connected to the negative electrode terminals 51 and positive electrode terminals 52 included in this second electrode terminal group. A conductive portion of a voltage sensor 90a is connected to each of the plurality of bus bars 70. Although not shown in FIG. 3, a voltage detection wiring 91 including a conductor is provided above the plurality of bus bars 70. The bus bar 70 connecting the negative electrode terminals 51 and positive electrode terminals 52 included in the second electrode terminal group corresponds to the second terminal connection portion.

[0069] As described above, many metal members are provided on the first end surface 50a of each of the multiple battery cells 50 included in the battery pack 20 on the first connecting wall 65 side and the second connecting wall 66 side. In the following, the wall virtually formed by the many metal members provided on the first connecting wall 65 side is referred to as the first metal wall 140, and the wall virtually formed by the many metal members provided on the second connecting wall 66 side is referred to as the second metal wall 150. In Figure 2, the first metal wall 140 and the second metal wall 150 are diagrammatically shown by dashed lines.

[0070] The above-mentioned waveguide path 160 is formed between the first metal wall 140 and the second metal wall 150 that are spaced apart in the x direction. The shape of the waveguide path 160 is defined between the first metal wall 140 and the second metal wall 150 in the x direction, and is defined between the first end surface 50a of each of the multiple battery cells 50 and the inner top surface 131a of the top wall 131 in the z direction. The area of ​​the inner top surface 131a facing the first end surface 50a corresponds to the facing surface.

[0071] The multiple battery cells 50 are lined up in the y direction as shown in Fig. 2. Therefore, the waveguide 160 has a shape that extends in the y direction. In addition, in a plane perpendicular to the y direction, the length of the waveguide 160 in the x direction is longer than the length in the z direction.

[0072] A separation distance a1 in the x direction between the terminal conductive portion 71 of the bus bar 70 included in the first metal wall 140 and the terminal conductive portion 71 of the bus bar 70 included in the second metal wall 150 is longer than half the fundamental wavelength λ and shorter than the same number as the fundamental wavelength λ. A separation distance a2 in the x direction between the terminal conductive portion 71 of the bus bar 70 included in one of the first metal wall 140 and the second metal wall 150 and the conductive extension portion 72 of the bus bar 70 included in the other is longer than half the fundamental wavelength λ and shorter than the same number as the fundamental wavelength λ. The separation distance a2 corresponds to the shortest length of the waveguide path 160 in the x direction. As shown in FIG. 3, the length of the waveguide path 160 in the x direction in the cross section taken along the line III-III shown in FIG. 2 is a2.

[0073] A distance b between the first end face 50a and the inner top surface 131a in the z direction is shorter than each of the distances a1 and a2. The distance b corresponds to the shortest length of the waveguide 160 in the z direction.

[0074] Due to this configuration, high-order electromagnetic waves having frequencies that are integer multiples of the fundamental frequency f are unlikely to penetrate into the waveguide 160. Furthermore, in the waveguide 160, the generation of such high-order electromagnetic waves is suppressed.

[0075] 2, there is a gap of a first separation distance w1 between any two battery cells 50 that are adjacent to each other in the y direction. There is a gap of a second separation distance w2 between the negative electrode terminal 51 of one of any two battery cells 50 that are adjacent to each other in the y direction and the positive electrode terminal 52 of the other of any two battery cells 50 that are adjacent to each other in the y direction. There is a gap of a third separation distance w3 between two bus bars 70 that are adjacent to each other in the y direction.

[0076] 3, there is a gap of a fourth separation distance w4 between the electrode terminal of the battery cell 50 and the bus bar 70. There is a gap of a fifth separation distance w5 between the bus bar 70 included in each of the first metal wall 140 and the second metal wall 150 and the inner top surface 131a of the top wall 131. Naturally, there are also gaps between the multiple conductive members included in each of the first metal wall 140 and the second metal wall 150.

[0077] The various gaps described above correspond to holes formed in the waveguide 160. The longest length of each of these gaps is shorter than half the fundamental wavelength λ. Among the various gaps described above, the gap between the bus bar 70 and the top wall 131 is larger than the other gaps. The fifth separation distance w5 of the gap between the bus bar 70 and the top wall 131 corresponds to the first longest separation distance and the second longest separation distance.

[0078] Strictly speaking, there is a gap between two bus bars 70 that are adjacent to each other in the y direction as shown in FIG. 2. The length of this gap in the z direction is the distance between the first end surface 50a of the battery cell 50 and the inner top surface 131a of the top wall 131. For this reason, the length of this gap in the z direction is longer than other gaps. However, a voltage detection wiring 91 including a conductor is provided above and between the two bus bars 70. This divides this gap in the z direction. The length of this divided gap in the z direction is shorter than half the fundamental wavelength λ.

[0079] <Waveguide> As shown in Fig. 1, the integrated monitoring unit 30 is housed in the hollow of a waveguide 170. A partition surface 170a that divides this hollow has the property of reflecting electromagnetic waves. The opening of the waveguide 170 functions to allow a wireless signal to enter the hollow of the waveguide 170 and to output a wireless signal from the hollow of the waveguide 170 to the outside. The hollow of the waveguide 170 corresponds to a common waveguide path.

[0080] This opening has a substantially rectangular parallelepiped shape. The length of the opening in the longitudinal direction is longer than half the fundamental wavelength λ, and shorter than the same period of the fundamental wavelength λ. Naturally, the length of the opening in the lateral direction is shorter than the length of the opening in the longitudinal direction. This configuration prevents the above-mentioned high-order electromagnetic waves from penetrating into the inside of the waveguide 170.

[0081] In addition, in the partition surface 170a, the shortest separation distance in a first plane direction along the aperture plane perpendicular to the aperture direction that perpendicularly passes through the aperture of the waveguide 170 is longer than half the fundamental wavelength λ, and shorter than the same number of fundamental wavelengths λ. In the partition surface 170a, the shortest separation distance in a second plane direction along the aperture plane and perpendicular to the first plane direction is shorter than the shortest separation distance in the first plane direction. Due to this configuration, the generation of the above-mentioned high-order electromagnetic waves in the hollow of the waveguide 170 is suppressed. The aperture direction corresponds to the extension direction. The first plane direction corresponds to the third direction. The second plane direction corresponds to the fourth direction.

[0082] <Action and effect> As described above, the individual communication unit 110 is provided in the waveguide path 160 whose length in the x direction is longer than half the fundamental wavelength λ and shorter than the same value of the fundamental wavelength λ, and whose length in the z direction is shorter than the length in the x direction.

[0083] This prevents high-order electromagnetic waves having frequencies that are integer multiples of the fundamental frequency f from penetrating the waveguide 160. At the same time, this prevents such high-order electromagnetic waves from being generated in the waveguide 160. This prevents standing waves from being generated in the waveguide 160 due to overlapping of high-order electromagnetic waves. This prevents the occurrence of places in the waveguide 160 where electromagnetic waves are likely to be strengthened and places where they are likely to be weakened. This prevents the individual communication unit 110 from having difficulty receiving wireless signals. This prevents wireless communication from being disturbed.

[0084] The waveguide path 160 is composed of a first metal wall 140 and a second metal wall 150 that are spaced apart in the x direction, and a plurality of battery cells 50 and a top wall 131 that are spaced apart in the z direction. In this way, the waveguide path 160 is composed of a plurality of battery cells 50, the first metal wall 140 and the second metal wall 150 that are electrically connected to the plurality of battery cells 50, and the case 40 that houses them. This prevents an increase in the number of parts.

[0085] The maximum length of the hole (gap) formed in the waveguide 160 is shorter than half the fundamental wavelength λ. Therefore, high-order electromagnetic waves are prevented from penetrating the waveguide 160 through the gap.

[0086] The integrated monitoring unit 30 is housed in the hollow of a waveguide 170 having an opening whose longitudinal length is longer than half the fundamental wavelength λ and shorter than the fundamental wavelength λ, and whose lateral length is shorter than the longitudinal length. The length of the first planar direction along the opening plane in the hollow of the waveguide 170 is longer than half the fundamental wavelength λ and shorter than the fundamental wavelength λ. The length of the second planar direction in the hollow of the waveguide 170 is shorter than the length of the first planar direction.

[0087] This prevents high-order electromagnetic waves from entering the waveguide 170. At the same time, it prevents high-order electromagnetic waves from being generated inside the waveguide 170. This prevents the integrated monitoring unit 30 from having difficulty receiving wireless signals.

[0088] As described above, it is possible to prevent the individual communication unit 110 and the integrated monitoring unit 30 from having difficulty receiving wireless signals. Therefore, it is possible to prevent wireless communication between the individual communication unit 110 and the integrated monitoring unit 30 from being interrupted.

[0089] Second embodiment In the first embodiment, for example, an example was shown in which the inner top surface 131a of the top wall 131 was flat, as shown in Fig. 3. In contrast to this, in this embodiment, a part of the inner top surface 131a of the top wall 131 protrudes towards the battery cell 50 side, as shown in Fig. 4.

[0090] More specifically, a protrusion 133 that protrudes locally in the z direction from an inner top surface 131a is formed on the top wall 131. This protrusion 133 extends continuously in the y direction.

[0091] Two protrusions 133 are formed on the top wall 131 for each battery pack 20. One of the two protrusions 133 faces the first metal wall 140 in the z direction while being spaced apart from it. The other of the two protrusions 133 faces the second metal wall 150 in the z direction while being spaced apart from it.

[0092] Due to this configuration, the separation distance between the top wall 131 and the first metal wall 140 and the separation distance between the top wall 131 and the second metal wall 150 are each a sixth separation distance w6 that is shorter than the fifth separation distance w5. As a result, the gap formed in the waveguide path 160 is small. As a result, even if the separation distance in the z direction between the battery pack 20 and the lid body 130 varies due to, for example, vibration, the gap formed in the waveguide path 160 is enlarged, thereby suppressing the intrusion of high-order electromagnetic waves into the waveguide path 160.

[0093] Moreover, the battery module 10 according to this embodiment and each of the battery modules 10 according to the following embodiments each include components equivalent to those of the battery module 10 described in the first embodiment. Therefore, the battery module 10 according to this embodiment and each of the following embodiments each achieves the same effects as the battery module 10 described in the first embodiment.

[0094] Third embodiment In each of the first and second embodiments, an example was shown in which the waveguide path 160 was configured by a plurality of battery cells 50, a first metal wall 140 and a second metal wall 150 electrically connected to the plurality of battery cells 50, and a case 40 that accommodates these. In contrast, in the present embodiment, a configuration can also be adopted in which the battery module 10 has an individual waveguide 180 that accommodates the individual communication unit 110 in a hollow space, as shown in, for example, Figures 5 and 6.

[0095] An inner wall surface 180a defining the hollow of the individual waveguide 180 has a property of reflecting electromagnetic waves. The hollow of the individual waveguide 180 functions as a waveguide path 160.

[0096] The shortest distance between the inner wall surfaces 180a in a first direction along a plane perpendicular to the extension direction of the individual waveguides 180 is longer than half the fundamental wavelength λ and shorter than the same wavelength. The shortest distance between the inner wall surfaces 180a in a second direction perpendicular to the first direction along this plane is shorter than the shortest length between the inner wall surfaces 180a in the first direction.

[0097] The individual waveguide 180 has an opening 181 that communicates between the hollow and the outside. The opening 181 of the individual waveguide 180 shown in Fig. 5 is open in the y direction. The opening 181 of the individual waveguide 180 shown in Fig. 6 is open in the z direction.

[0098] The planar shape of these openings 181 is a rectangular parallelepiped. The length of the openings 181 in the longitudinal direction is longer than half the fundamental wavelength λ and shorter than the same value. Naturally, the length of the openings 181 in the lateral direction is shorter than the length in the longitudinal direction.

[0099] This configuration eliminates the need to determine the frequency band of the wireless signal depending on the shapes and arrangement of the battery cells 50 and the case 40 included in the battery pack 20. In other words, it eliminates the need to determine the shapes and arrangement of the battery cells 50 and the case 40 depending on the frequency band of the wireless signal. This prevents the design of the battery pack 20 from becoming difficult.

[0100] Note that the individual waveguide 180 may have a hole that communicates the hollow with the outside. The longest length of the hole needs to be shorter than half the fundamental wavelength λ. For this reason, a metal mesh or the like having openings and holes that satisfy the above conditions may be used as the individual waveguide 180. This allows for weight reduction.

[0101] (Fourth embodiment) In the third embodiment, an example was shown in which the hollow of the individual waveguide 180 functions as the waveguide path 160. In contrast, in the present embodiment, the individual waveguide 180 and the conductive member 82 of the wiring board 81 function as the waveguide path 160.

[0102] 7 is provided on the wiring board 81 in a manner that covers the mounting surface 81a of the wiring board 81 for the individual communication unit 110. A conductive member 82 is provided in an area of ​​the mounting surface 81a aligned with the individual waveguide 180 in the z direction.

[0103] With this configuration, the individual communication section 110 is provided inside the individual waveguide 180. At the same time, the opening of the individual waveguide 180 in the z direction is closed by the wiring board 81. As a result, the individual waveguide 180 and the conductive member 82 form a waveguide path 160.

[0104] The length of the waveguide 160 in the x direction is longer than half the fundamental wavelength λ and shorter than the same wavelength. The length of the waveguide 160 in the z direction is shorter than the length in the x direction.

[0105] It is also possible to employ a configuration in which the conductive member 82 is provided on the back surface 81b of the mounting surface 81a of the wiring board 81. It is also possible to employ a configuration in which the conductive member 82 is not provided on the wiring board 81. In the case of this modification, the waveguide path 160 is constituted by the individual waveguides 180 and a metal case in which the multiple battery cells 50 are provided.

[0106] Although the above describes preferred embodiments of the present disclosure, the present disclosure is not limited to the above-described embodiments and can be modified in various ways without departing from the spirit and scope of the present disclosure.

[0107] (First Modification) In each embodiment, an example has been shown in which the wiring board 81 on which the individual communication unit 110 is mounted is provided on the first end surface 50a of the multiple battery cells 50. However, for example, as shown in Fig. 8 and Fig. 9, a configuration in which the wiring board 81 is provided on the inner top surface 131a of the top wall 131 can also be adopted. In particular, as shown in Fig. 9, a configuration in which the individual waveguide 180 described in the fourth embodiment is provided on the top wall 131 in a manner surrounding the wiring board 81 can also be adopted. Although not shown, a configuration in which the individual waveguide 180 described in the third embodiment is provided on the top wall 131 can also be adopted.

[0108] (Second Modification) In each embodiment, an example has been shown in which the wiring board 81 on which the individual communication unit 110 is mounted is provided in the waveguide path 160. However, as long as the individual communication unit 110 is provided in the waveguide path 160, the wiring board 81 does not have to be provided in the waveguide path 160. The individual monitoring unit 100 does not have to be provided in the waveguide path 160.

[0109] (Third Modification) In the first embodiment, an example has been shown in which the length of the waveguide 160 in the x direction is longer than the length in the z direction. However, a configuration in which the length of the waveguide 160 in the x direction is shorter than the length in the z direction may also be adopted. The length of the waveguide 160 in the z direction is longer than half the fundamental wavelength λ and shorter than the same wavelength. Such a modified example can be appropriately adopted depending on, for example, the shape of the battery cells 50 included in the battery pack 20 and the frequency band of the wireless signal to be used.

[0110] (Fourth Modification) In each embodiment, an example has been shown in which the individual communication unit 110 is provided between the multiple battery cells 50 and the top wall 131. However, when the battery module 10 has the individual waveguide 180 described above and the individual communication unit 110 is housed in the hollow of the individual waveguide 180, there is no particular limitation on the location of the individual communication unit 110. For example, a configuration in which the individual waveguide 180 that houses the individual communication unit 110 is provided in the battery case 60 may also be adopted. [Explanation of symbols]

[0111] 10...battery module, 20...battery pack, 30...integrated monitoring unit, 40...case, 50...battery cell, 50a...first end surface, 51...negative terminal, 52...positive terminal, 60...battery case, 70...bus bar, 90...sensor, 90a...voltage sensor, 110...individual communication unit, 120...housing, 130...lid, 131...top wall, 131a...inner top surface, 133...projection, 140...first metal wall, 150...second metal wall, 160...waveguide path, 170...waveguide, 170a...partition surface, 180...individual waveguide, 180a...inner wall surface, 181...opening, 200...battery ECU

Claims

1. A plurality of assembled batteries (20); a plurality of individual detection units (90) for individually detecting physical quantities of the respective plurality of assembled batteries; a plurality of individual communication units (110) for outputting the detection results of the respective plurality of individual detection units by wireless signals; A monitoring unit (30) that wirelessly communicates with each of the plurality of individual communication units; an individual waveguide (180) in which the individual communication unit is housed in an internal waveguide path (160); a battery module having an electromagnetic reflection housing (40) that houses a plurality of the assembled batteries, a plurality of the individual detection units, a plurality of the individual communication units, the monitoring unit, and the individual waveguides in a storage space;

2. A wiring board (81) on which the individual communication unit is mounted, The battery module according to claim 1 , wherein an opening is formed in the individual waveguide, and the waveguide path is formed by closing the opening with the wiring board.

3. The battery pack includes a plurality of battery cells (50) each having an electrode terminal (51, 52) formed on an electrode forming surface (50a) of a metal case, 3. The battery module according to claim 1, wherein the individual waveguides are provided separated from the electrode formation surface by a space.

4. the individual waveguides are provided in a manner facing the electrode formation surface, The battery module according to claim 3 , wherein the electrode terminals are provided spaced apart from the individual waveguides.

5. The battery module according to claim 3 or claim 4, wherein the individual communication unit is provided on the opposing surface side in the opposing direction between the electrode forming surface and an opposing surface (131a) that faces the electrode forming surface in the electromagnetic reflective housing.

6. A battery pack (20), an individual communication unit (110) that outputs a detection result of a physical quantity of the battery pack by a wireless signal; A monitoring unit (30) that wirelessly communicates with the individual communication unit; an individual waveguide (180) in which the individual communication unit is housed in an internal waveguide path (160); a housing (40) that houses the assembled battery, the individual communication unit, the monitoring unit, and the individual waveguide in a storage space;

Images