Electronic circuit unit and battery module

Abstract

To improve the strength of an electronic circuit unit in which a heavy object is installed. [Solution] The electronic circuit unit 10 comprises a lower substrate 11 having a surface including an upper surface and a lower surface along a horizontal plane, a heavy object (switching unit 20) supported on the upper surface of the lower substrate 11 and electrically connected to wiring 30 on the lower substrate 11, and a bus bar 40 attached to the surface of the lower substrate 11, constituting the wiring 30, and arranged so as to overlap the heavy object in a planar view.

Description

[Technical Field]

[0001] The present invention relates to an electronic circuit unit and a battery module. [Background technology]

[0002] Patent Document 1 discloses an electronic circuit unit in which electronic devices are mounted on an electronic circuit board. The electronic devices mounted on the board include power transistors that generate a large amount of heat. Since a circuit connected to the power transistor requires a large current to flow, a bus bar is provided on the board. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-274421 Summary of the Invention [Problem to be solved by the invention]

[0004] Such electronic circuit units may be used as built-in or external devices for battery modules. Since heavy components such as iron cores and copper coils are installed in electronic circuit units for battery modules, the boards must be strong. However, the electrical junction box does not take this into consideration.

[0005] An object of the present invention is to improve the strength of an electronic circuit unit in which a heavy object is provided. [Means for solving the problem]

[0006] One aspect of the present invention provides an electronic circuit unit comprising: a substrate having a surface including an upper surface and a lower surface along a horizontal plane; a heavy object supported on the upper surface of the substrate and electrically connected to wiring on the substrate; and a bus bar attached to the surface of the substrate, constituting the wiring, and arranged so as to overlap the heavy object in a planar view.

[0007] One aspect of the present invention provides a battery module including the electronic circuit unit and a battery cell module connected to the electronic circuit unit. [Effects of the Invention]

[0008] According to the present invention, the strength of an electronic circuit unit in which a heavy object is provided can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a battery module according to an embodiment. [Figure 2] Schematic diagram of the battery module in Figure 1. [Figure 3] FIG. 3 is a perspective view of the electronic circuit unit of FIG. 2 as seen from above. [Figure 4] FIG. 3 is a perspective view of the electronic circuit unit of FIG. 2 as seen from below. [Figure 5] FIG. 3 is an exploded perspective view of the electronic circuit unit of FIG. 2. [Figure 6] FIG. 5 is a perspective view of the bus bar of FIG. 4 as seen from above. [Figure 7] 4 is a plan view of the electronic circuit unit of FIG. 3 with the upper substrate removed. [Figure 8] FIG. 4 is a side view of the electronic circuit unit of FIG. 3 . [Figure 9] FIG. 10 is a perspective view of a bus bar according to a first modified example. [Figure 10] FIG. 10 is a perspective view of a bus bar according to a second modified example. [Figure 11] FIG. 11 is a perspective view of a bus bar according to a third modified example. [Figure 12] FIG. 10 is a perspective view of a bus bar according to a fourth modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or corresponding elements are designated by the same reference numerals throughout the drawings, and detailed descriptions thereof will be omitted.

[0011] An electronic circuit unit according to one embodiment of the present invention comprises a substrate having a surface including an upper surface and a lower surface along a horizontal plane, a heavy object supported on the upper surface of the substrate and electrically connected to wiring on the substrate, and a bus bar attached to the surface of the substrate, constituting the wiring, and arranged so as to overlap the heavy object in a planar view.

[0012] According to the above configuration, the bus bar is arranged to overlap the heavy object in a plan view, and the gravitational load acting on the board from the heavy object is received by the bus bar, thereby suppressing deformation of the board and, in turn, deformation of the electronic circuit unit.

[0013] In an electronic circuit unit according to another embodiment of the present invention, the bus bar may have a board abutment portion that makes surface contact with the surface of the board within a region that overlaps with the heavy object in a plan view.

[0014] According to the above configuration, the gravity load is easily transferred to the bus bar at the board contact portion, and the load shared by the board is easily reduced.

[0015] In the electronic circuit unit according to another embodiment of the present invention, the board contact portion may be provided with a conductive member that is electrically connected to the heavy object.

[0016] According to the above configuration, the board contact portion overlaps the heavy object in a plan view and is in surface contact with the board. By providing the conductive member at such a board contact portion, the structure for electrically connecting the bus bar to the heavy object can be made compact.

[0017] In the electronic circuit unit according to another embodiment of the present invention, the conductive member may be a metal fastener that fixes the board contact portion to the board and the heavy object.

[0018] According to the above configuration, when the board contact portion is mechanically fixed to the board, the bus bar is electrically connected to the heavy object, which simplifies the assembly work of the electronic circuit unit.

[0019] In the electronic circuit unit according to another embodiment of the present invention, the bus bar may extend along the longitudinal direction of the substrate.

[0020] With the above configuration, the board may bend downward due to the gravitational load from a heavy object, causing the longitudinal center portion to bend downward relative to the longitudinal ends. However, because the bus bars extend along the longitudinal direction, such bending deformation is suppressed.

[0021] In an electronic circuit unit according to another embodiment of the present invention, a pair of end fixing points for fixing the bus bar to the substrate may be set at both ends of the bus bar.

[0022] According to the above configuration, the pair of end fixing points are arranged as far apart as possible along the longitudinal direction of the substrate, which makes it easier to suppress bending deformation of the substrate.

[0023] In an electronic circuit unit according to another embodiment of the present invention, at least one of the one end and the other end of the bus bar may protrude in the longitudinal direction relative to the heavy object in a planar view, and at least one of the pair of end fixing points may be positioned outside the heavy object in a planar view.

[0024] According to the above configuration, at least one of the pair of end fixing points is disposed on the outer side of the heavy object in a plan view, which makes it easier to suppress bending deformation of the substrate.

[0025] An electronic circuit unit according to another embodiment of the present invention may further include a case that supports the substrate, and a unit fixing point that fixes the substrate to the case may be set on the edge of the substrate, and at least one of the pair of end fixing points may be positioned between the heavy object and the unit fixing point when viewed in a plane.

[0026] According to the above configuration, at least one of the pair of ends of the bus bar is fixed to the substrate between the heavy object and the unit fixing point, which makes it easier to suppress bending deformation of the substrate.

[0027] In an electronic circuit unit according to another embodiment of the present invention, the bus bar may have a main portion extending in the longitudinal direction along the surface, and a rib protruding upward or downward from a peripheral edge of the main portion and extending in the longitudinal direction.

[0028] According to the above configuration, the presence of the ribs extending in the longitudinal and height directions further suppresses bending deformation of the substrate.

[0029] In the electronic circuit unit according to another embodiment of the present invention, the bus bar may be attached to the lower surface of the substrate.

[0030] According to the above configuration, it is easy to realize a configuration in which the bus bar overlaps the heavy object in a plan view, and a configuration in which the bus bar is in surface contact with the board within this overlapping region.

[0031] A battery module according to an embodiment of the present invention includes an electronic circuit unit according to any one of claims 1 to 4, and a battery cell module connected to the electronic circuit unit.

[0032] According to the above configuration, it is possible to provide a battery module that can suppress deformation of the substrate and therefore the electronic circuit unit.

[0033] In the battery module according to another embodiment of the present invention, the electronic circuit unit may include, as the heavy object, a DC voltage conversion circuit for converting a DC voltage.

[0034] According to the above configuration, deformation of the substrate supporting the DC voltage conversion circuit can be suppressed.

[0035] Specific examples of the present invention will be described in detail below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms incorporating these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. Furthermore, parts with the same reference numerals appearing in multiple drawings indicate identical or equivalent parts or components. Furthermore, the embodiments described below are illustrative examples of the technical concept of the present invention and do not limit the scope of the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment or example can also be applied to other embodiments or examples. Furthermore, the sizes and positional relationships of components shown in the drawings may be exaggerated for clarity.

[0036] The battery module of the present invention is applied to, for example, an emergency power source such as a battery backup unit (BBU), etc. However, the present invention does not specify the use of the battery module, and the battery module can be used as a power source for various other electrical devices, such as a power source for a vehicle traction motor.

[0037] 1, a battery module 1 includes a case 2. The case 2 has a rectangular parallelepiped shape. A connector 3 is attached to an end face of the case 2. The connector 3 can be connected to an external power source or an electrical load.

[0038] Referring to FIG. 2, the case 2 houses the battery cell modules 5 and electronic circuit unit 10 of the battery module 1. The battery cell modules 5 are secondary batteries that can be repeatedly charged and discharged, such as lithium-ion batteries, nickel-metal hydride batteries, or lead-acid batteries, and store DC power. When an external power source is connected to the connector 3, the battery cell modules 5 can be charged with power supplied from the external power source. When an electrical load is connected to the connector 3, power discharged from the battery cell modules 5 can be supplied to the electrical load.

[0039] The electronic circuit unit 10 is spatially and electrically disposed between the connector 3 and the battery cell module 5. The electronic circuit unit 10 includes a switching unit 20 and wiring 30. The wiring 30 connects the switching unit 20 to the connector 3 and the battery cell module 5. The switching unit 20 converts voltage when power is supplied between the connector 3 (i.e., an external power source or an electrical load) and the battery cell module 5. "Voltage conversion" includes not only stepping down and stepping up, but also conversion from AC to DC and vice versa. The switching unit 20 includes a discharge converter 21 that operates when the battery cell module 5 is discharging, and a charge converter 22 that operates when the battery cell module 5 is charging.

[0040] 3 to 5, the electronic circuit unit 10 includes a plurality of substrates. Most of the wiring 30 is realized by a conductive material pattern printed on the surface of the substrate. Some of the wiring 30 is formed by a plurality of tabs 35 and bus bars 40 attached to the substrate.

[0041] As just one example, the multiple substrates include a lower substrate 11, an upper substrate 12, and one or more charge / discharge substrates 13 (for example, one for charging and three for discharging). Each substrate is made of a synthetic resin material and is flat. The lower substrate 11 and the upper substrate 12 are arranged in a horizontal position. The surfaces of the lower substrate 11 and the upper substrate 12 include upper and lower surfaces along a horizontal plane. The lower substrate 11 is generally rectangular in plan view. Hereinafter, the long side direction of this rectangle will be referred to as the "longitudinal direction X," the short side direction will be referred to as the "width direction Y," and the direction (up-down direction) perpendicular to both the longitudinal direction X and the width direction Y will be referred to as the "height direction Z." The charge / discharge substrate is sandwiched between the lower substrate 11 and the upper substrate 12. The switching unit 20 (particularly the discharge converter 21) is a heavy object including an iron core and a copper coil, is supported on the upper surface of the lower substrate 11, and is electrically connected to wiring 30 on the lower substrate 11.

[0042] Referring to Figure 5, a connector 3 and a terminal block 4 are provided on the upper surface of the lower substrate 11. The connector 3 is located at one end in the longitudinal direction and is partially exposed to the outside of the case 2 when the electronic circuit unit 10 is housed in the case 2. The terminal block 4 is located at the other end in the longitudinal direction. The wiring on the lower substrate 11 is connected to the battery cell module 5 via a cable (not shown) connected to the terminal block 4.

[0043] The tab 35 is made of a conductive material, such as a metal material such as a copper alloy, stainless steel, or aluminum alloy. The tab 35 is L-shaped and manufactured by pressing a plate of such a material. The tab 35 has a horizontal portion 36 that is placed on the upper surface of the lower substrate 11 and a vertical portion 37 that is bent at the edge of the horizontal portion 36 and placed on the surface of the charge-discharge substrate. The tab 35 is attached to the lower substrate 11 with the vertical portion 37 extending in the longitudinal direction X and the height direction Z, i.e., with the vertical portion 37 extending parallel to the charge-discharge substrate. For example, a bolt is used to attach the tab 35. In this case, the bolt is inserted upward into the lower substrate 11 and threaded into the female thread provided on the tab 35. The bolt is inserted from the side of the charge-discharge substrate and threaded into the female thread provided on the tab 35. This establishes electrical continuity between the wiring pattern printed on the lower substrate 11 and the wiring pattern printed on the charge-discharge substrate via the tab 35. A plurality of tabs 35 are similarly attached to the upper substrate 12.

[0044] 4 and 5, bus bar 40 is attached to the surface of the substrate, or in this embodiment, the lower surface of the lower substrate. Bus bar 40 is made of a conductive material, such as a metal material such as a copper alloy, stainless steel, or aluminum alloy. Bus bar 40 is produced by pressing a plate of such a material.

[0045] 4 and 6, bus bar 40 extends along longitudinal direction X. Bus bar 40 has a board contact portion 41, a pair of end contact portions (first end contact portion 42 and second end contact portion), a pair of connecting portions (first connecting portion 44 and second connecting portion 45), a pair of central upright wall portions (first central upright wall portion 46 and second central upright wall portion 47), and a pair of end upright wall portions (first end upright wall portion 48 and second end upright wall portion 49).

[0046] The board contact portion 41, the pair of end contact portions 42, 43, and the pair of connecting portions 44, 45 extend horizontally along the underside of the lower substrate 11. The board contact portion 41 is located at the center in the longitudinal direction X, and the pair of end contact portions 42, 43 are located at both ends in the longitudinal direction X. The first connecting portion 44 is located between the board contact portion 41 and the first end contact portion 42 on one side in the longitudinal direction X, and the second connecting portion 45 is located between the board contact portion 41 and the second end contact portion 43 on the other side in the longitudinal direction X. The board contact portion 41 and the pair of end contact portions 42, 43 are located above the pair of connecting portions 44, 45 and are in surface contact with the underside of the lower substrate 11. The pair of connecting portions 44, 45 are slightly spaced downward from the underside of the lower substrate 11.

[0047] The board contact portion 41 has a central bus 41a extending in the width direction Y at the center of the longitudinal direction X, one or more first central terminals 41b and one or more first protrusions 41d protruding from the central bus 41a to one side in the longitudinal direction X, and one or more second central terminals 41c and one or more second protrusions 41e protruding from the central bus 41a to the other side in the longitudinal direction X.

[0048] In this embodiment, merely by way of example, there are three first central terminals 41b and three second central terminals 41c, two first protrusions, and three second protrusions. The three first central terminals 41b and the two first protrusions 41d are alternately arranged in the width direction Y. The three second central terminals 41c and the two second protrusions 41e are alternately arranged in the width direction Y. The first central terminals 41b and the second central terminals 41c protrude more in the longitudinal direction X than the first protrusions 41d and the second protrusions 41e when viewed from the central bus 41a.

[0049] As viewed from the central bus 41a, pairs of the first central terminal 41b and the second central terminal 41c and pairs of the first protrusion 41d and the second protrusion 41e are arranged alternately from one side to the other in the width direction Y. In each pair, the two elements constituting the pair are located at the same position in the width direction Y and protrude in opposite directions in the longitudinal direction X. At the end on the other side in the width direction Y, the second protrusion 41e protrudes independently from the central bus 41a without forming a pair with the first protrusion 41d.

[0050] The first connecting portion 44 has a first assembly portion 44a that is continuous with the first end abutting portion 42 via a first end standing wall portion 48, and multiple first extending portions 44b that branch off and extend from the first assembly portion 44a. The multiple first extending portions 44b are arranged at intervals in the width direction Y and extend parallel to each other in the longitudinal direction X. The first extending portion 44b connects to the first assembly portion 44a on one side in the longitudinal direction X and connects to the first protruding portion 41d of the board abutting portion 41 via a first central standing wall portion 46 on the other side in the longitudinal direction X. The number of first extending portions 44b is the same as the number of first protruding portions 41d, which is two in this example. The first connecting portion 44 has an opening 44c surrounded by the two first extending portions 44b and the first assembly portion 44a.

[0051] The second connection portion 45 includes a second assembly portion 45a that connects to the second end abutment portion 43 via a second end standing wall portion 49, and multiple second extension portions 45b that branch off and extend from the second assembly portion 45a. The multiple second extension portions 45b are arranged at intervals in the width direction Y and extend parallel to each other in the longitudinal direction X. The second extension portion 45b connects to the second assembly portion 45a on one side in the longitudinal direction X and connects to the second protrusion portion 41e of the board abutment portion 41 via a second central standing wall portion 47 on the other side in the longitudinal direction X. The number of second extension portions 45b is the same as the number of second protrusions 41e, which is three in this example. The second connection portion 45 further includes a bridge portion 45d that connects the centers of the three second extension portions 45b in the width direction Y. The second connection portion 45 has three second extension portions 45b, a bridge portion 45d, and four openings 45c surrounded by the second collection portion 45a.

[0052] One through hole 41f is provided in each of the first central terminal 41b and the second central terminal 41c of the board contact portion 41. Two through holes 42a and two through holes 43a are provided in each of the first end contact portion 42 and the second end contact portion 43.

[0053] 4, bus bar 40 is fixed to lower substrate 11 with the upper surfaces of board contact portion 41, first end contact portion 42, and second end contact portion 43 in surface contact with the lower surface of lower substrate 11. This surface contact causes central terminals 41b and 41c of board contact portion 41 to overlap a wiring pattern printed on the lower surface of lower substrate 11.

[0054] In this embodiment, bolts 61 and 62 are used for fixing. The bolt 61 is an example of a conductive member made of a conductive material such as stainless steel, and is an example of a fastener for fixing the substrate contact portion 41 to the lower substrate 11 and the switching portion 20. The bolt 62 is an example of a fastener for fixing the pair of end contact portions 42 and 43 to the lower substrate 11.

[0055] The bolts 62 are inserted from bottom to top through the through holes 42a, 43a of the end abutment portions 42, 43, pass through the lower substrate 11, and are screwed into nuts 64 fixed to the upper surface of the lower substrate 11. The through holes 42a, 43a and the bolts 62 and nuts 64 assembled thereto correspond to end fixing points set at both ends of the bus bar 40, and the bus bar 40 is fixed to the lower substrate 11 at the end fixing points.

[0056] The bolt 61 is inserted from bottom to top through the through-hole 41f of each central terminal 41b, 41c, penetrates the lower substrate 11, further penetrates the horizontal portion 36 of the tab 35, and is screwed into the female thread provided on the tab 35. This allows the wiring pattern on the lower surface of the lower substrate 11 to be conducted to the wiring pattern printed on the charge / discharge substrate of the switching unit 20 via the central terminals 41b, 41c, the bolt 61, and the tab 35. The through-hole 41f and the bolt 61 assembled thereto correspond to a central fixing point set at the center of the bus bar 40 in the longitudinal direction X, and the bus bar 40 is fixed to the lower substrate 11 at the central fixing point as well.

[0057] 7, bus bar 40 is arranged so as to overlap switching unit 20, which is a heavy object, in a plan view. Board contact portion 41 is in surface contact with lower substrate 11 within the area that overlaps switching unit 20, which is a heavy object, in a plan view.

[0058] In this embodiment, one end of the busbar 40, i.e., the first end contact portion 42 and the end fixing point set thereon, overlap with the switching unit 20 in a plan view. On the other hand, the other end of the busbar 40, i.e., the second end contact portion 43 and the end fixing point set thereon, are arranged outside the switching unit 20 in a plan view. Specifically, the second end contact portion 43 protrudes to the other side in the longitudinal direction X relative to the switching unit 20, and the end fixing point set at the second end contact portion 43 is arranged close to the terminal block 4.

[0059] The lower substrate 11 has a rectangular shape in a plan view, and has through holes 11a formed at its four corners. Bolts (not shown) for fixing the lower substrate 11 to the case 2 (see FIG. 1) are inserted into the through holes 11a. The through holes 11a and the bolts attached thereto correspond to unit fixing points for fixing the lower substrate 11, and therefore the electronic circuit unit 10, to the case 2.

[0060] 7 and 8, the other end fixing point (fixing point set at the second end abutment portion 43) is positioned outside the switching unit 20 as a heavy object in a plan view, and is positioned between the switching unit 20 and the unit fixing point (particularly, the fixing point positioned at the other end of the longitudinal direction X) in the longitudinal direction X.

[0061] Referring to Figure 8, in a side view, the "distance between the unit fixing point and the center of gravity G of the heavy load" is defined as "L," the "distance between the unit fixing point and an end fixing point adjacent thereto in the longitudinal direction" is defined as "L1," and the "distance between the center of gravity G and the central fixing point" is defined as "L2." The unit fixing point, the end fixing point, and the central fixing point are arranged so that the sum of distance L1 and distance L2 is shorter than distance L. This applies to both sides of the center of gravity G in the longitudinal direction X.

[0062] As such, the electronic circuit unit 10 of this embodiment comprises a lower substrate 11 having a surface including an upper surface and a lower surface along a horizontal plane, a heavy object supported on the upper surface of the lower substrate 11 and electrically connected to the wiring on the lower substrate 11, and a bus bar 40 attached to the surface of the lower substrate 11, constituting wiring 30, and arranged so as to overlap the heavy object in a planar view.

[0063] As a result, the gravitational load acting on the lower substrate 11 from the heavy object is received by the bus bar 40. Deformation of the lower substrate 11, and therefore deformation of the electronic circuit unit 10, can be suppressed.

[0064] Busbar 40 has substrate abutment portion 41 that comes into surface contact with the surface of lower substrate 11 in the area that overlaps with the heavy object in a plan view. This makes it easier for the gravitational load to flow to busbar 40 at substrate abutment portion 41, making it easier to reduce the load shared by lower substrate 11.

[0065] The board contact portion 41 is provided with a conductive member that is electrically connected to the heavy object. The board contact portion 41 overlaps the heavy object in a plan view and is in surface contact with the lower substrate 11. By providing the conductive member on such board contact portion 41, the structure for electrically connecting the bus bar 40 to the heavy object becomes compact. The conductive member is a metal fastener that fixes the board contact portion 41 to the lower substrate 11 and the heavy object. When the board contact portion 41 is mechanically fixed to the lower substrate 11, the bus bar 40 is electrically connected to the heavy object. This simplifies the assembly work of the electronic circuit unit 10.

[0066] The gravitational load from a heavy object may cause bending deformation in the lower substrate 11, such that the central portion in the longitudinal direction X is bent downward relative to both ends in the longitudinal direction. Since the busbar 40 extends along the longitudinal direction of the lower substrate 11, such bending deformation is suppressed.

[0067] A pair of end fixing points for fixing the bus bar 40 to the lower substrate 11 is set at both ends of the bus bar 40. The pair of end fixing points is arranged as far apart as possible along the longitudinal direction of the lower substrate 11. This makes it easier to suppress bending deformation of the lower substrate 11.

[0068] At least one of one end and the other end of the bus bar 40 protrudes in the longitudinal direction X relative to the heavy object in a plan view, and at least one of the pair of end fixing points is disposed outside the heavy object in a plan view. Since at least one of the pair of end fixing points is disposed outside the heavy object in a plan view, bending deformation of the board can be more easily suppressed.

[0069] The device further includes a case 2 that supports the lower substrate 11, and unit fixing points for fixing the lower substrate 11 to the case 2 are set on the peripheral edges of the lower substrate 11, with at least one of the pair of end fixing points being disposed between the heavy load and the unit fixing point in a plan view. Because at least one of the pair of ends of the bus bar 40 is fixed to the lower substrate 11 between the heavy load and the unit fixing point, bending deformation of the lower substrate 11 can be more easily suppressed.

[0070] Although the embodiment has been described above, the above configuration is merely an example and can be modified as appropriate within the scope of the present invention.

[0071] 9, busbar 40 may have ribs 40a that protrude upward from the substrate surface and extend in longitudinal direction X. The presence of ribs 40a increases the second moment of area of ​​busbar 40 when busbar 40 is bent such that the central portion in longitudinal direction X is directed downward relative to both longitudinal ends. This further suppresses deformation of lower substrate 11.

[0072] In the above embodiment and in Fig. 9, fasteners are used to secure the bus bar 40 to the substrate, but this is just one example. As shown in Fig. 10, the bus bar 40 may have an insertion piece 40b that is inserted into a slot 11b that opens in the substrate. The insertion piece 40b is electrically connected to a wiring pattern printed near the slot 11b by soldering, and the bus bar 40 is secured to the substrate by this soldering.

[0073] 9, L-shaped bus bar 40 has ribs 40a and is fixed by fastening, but this is just one example. As shown in FIG. 11, bus bar 40 may have a hat-shaped cross section. In this case, since there are two ribs 40a, deformation of lower substrate 11 is further suppressed.

[0074] In Fig. 10, I-shaped bus bar 40 has ribs 40a and is fixed by soldering, but this is just one example. As shown in Fig. 12, bus bar 40 may be U-shaped. In this case, too, there are two ribs 40a, which further suppresses deformation of lower substrate 11.

[0075] Both ends of the bus bar 40 in the longitudinal direction X may protrude in the longitudinal direction X relative to the heavy object.

[0076] The electronic circuit unit is not limited to a converter for controlling charging and discharging, but may be applied to other circuit units having heavy loads.The electronic circuit unit is not limited to a component of a battery module, but may be applied to other electronic devices. [Explanation of symbols]

[0077] 1 Battery Module 2 cases 3 Connectors 4 Terminal block 5 Battery Cell Module 10 Electronic circuit unit 11 Lower board 11a Through hole 11b Slot 12 Upper board 13 Charge / discharge board 20 Switching section 21 Discharge Converter 22 Charging Converter 30 Wiring 35 tabs 36 Horizontal section 37 Vertical section 40 Busbar 40a Rib 40b Insert 41 Board contact part 41a Chuo Bus 41b 1st center terminal 41c 2nd center terminal 41d 1st protrusion 41e 2nd protrusion 41f through hole 42 First end contact part 42a through hole 43 Second end contact part 43a through hole 44 First connection part 44a 1st gathering area 44b 1st extension part 44c aperture 45 Second connection part 45a 2nd assembly area 45b 2nd extension part 45c aperture 45d bridge 46 First central vertical wall 47 Second central vertical wall 48 First end vertical wall portion 49 Second end vertical wall 61 volts 62 volts 64 Nut G center of gravity L distance L1 distance L2 distance X Longitudinal direction Y width direction Z height direction

Claims

1. a substrate having a surface including an upper surface and a lower surface along a horizontal plane; a weight supported on the upper surface of the substrate and electrically connected to wiring on the substrate; a bus bar attached to the surface of the substrate, constituting the wiring, and arranged so as to overlap the heavy object in a plan view; Equipped with the bus bar extends along the longitudinal direction of the substrate; a pair of end fixing points for fixing the bus bar to the substrate are provided at both ends of the bus bar; At least one of one end and the other end of the bus bar protrudes in the longitudinal direction relative to the heavy object in a plan view, At least one of the pair of end fixing points is disposed on the outer side of the heavy object in a plan view. Electronic circuit unit.

2. the bus bar has a board abutment portion that is in surface contact with the surface of the board within a region that overlaps with the heavy object in a plan view; The electronic circuit unit according to claim 1 .

3. The board contact portion is provided with a conductive member electrically connected to the heavy object. The electronic circuit unit according to claim 2 .

4. the conductive member is a metal fastener that fixes the board contact portion to the board and the heavy object; The electronic circuit unit according to claim 3 .

5. Further comprising a case for supporting the substrate; a unit fixing point for fixing the substrate to the case is set at a corner of the substrate; At least one of the pair of end fixing points is disposed between the weight and the unit fixing point in a plan view. The electronic circuit unit according to any one of claims 1 to 4.

6. the bus bar has a rib that protrudes upward or downward from the surface of the substrate and extends in the longitudinal direction; The electronic circuit unit according to any one of claims 1 to 4.

7. the bus bar is attached to the bottom surface of the substrate; The electronic circuit unit according to any one of claims 1 to 4.

8. an electronic circuit unit according to any one of claims 1 to 4; a battery cell module connected to the electronic circuit unit; A battery module comprising:

9. The electronic circuit unit includes a switching unit that converts voltage. The battery module according to claim 8 .

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