Electrical junction box

Abstract

An electrical junction box (100) is equipped with a housing in which a plurality of bus bars (10) are housed and dissipates heat from the bus bars (10) to the outside via the housing. The electrical junction box (100) comprises: a first heat dissipation unit (70) that is separated from the bus bar (10) by a first distance or less and dissipates heat by radiation; and a second heat dissipation unit (60) that is separated from the bus bar (10) by a second distance or more and dissipates heat by convection.

Description

[Technical Field]

[0001] The present disclosure relates to an electrical junction box. This application claims priority from Japanese Application No. 2022-146344, filed September 14, 2022, and incorporates by reference all of the contents of said Japanese application. [Background technology]

[0002] 2. Description of the Related Art Conventionally, many vehicles are provided with an electrical connection device that is interposed between a power source and electrical components to supply electric power.

[0003] Patent document 1 discloses an electrical connection device that includes a housing that accommodates an electromagnetic relay, and that has an opening in the housing near the electromagnetic relay to radiate heat from inside the housing to the outside. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-83160 Summary of the Invention

[0005] An electrical connection box according to an embodiment of the present disclosure includes a housing that houses a plurality of bus bars and dissipates heat from the bus bars to the outside through the housing, and includes a first heat dissipation section that is spaced a first distance or less from the bus bars and dissipates heat by radiation, and a second heat dissipation section that is spaced a second distance or more from the bus bars and dissipates heat by convection. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a perspective view of an electrical junction box according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view of the electrical junction box according to the embodiment. [Figure 3]FIG. 2 is a bottom view of the electrical junction box according to the embodiment. [Figure 4] 1 is a plan view showing a state in which an upper case is removed in the electrical junction box according to the present embodiment; [Figure 5] 1 is a perspective view showing a state in which an upper case is removed in an electrical junction box according to an embodiment of the present invention; [Figure 6] FIG. 6 is a longitudinal cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is a vertical cross-sectional view taken along line VII-VII in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0007] [Problem to be solved by the invention] For example, in the case of electronic components such as relays that generate heat when powered on, it is practically impossible to expect a significant heat dissipation effect from heat dissipation from the electronic component itself, and heat dissipation via a bus bar that is connected to such electronic component and exposed to the air is more efficient.

[0008] However, in the electrical connection device of Patent Document 1, the opening is provided in the housing at a position near the electromagnetic relay, and heat is only dissipated from the electromagnetic relay itself, with no consideration given to heat dissipation via the bus bar, so it is difficult to say that the heat from the electromagnetic relay is dissipated efficiently.

[0009] Therefore, an object of the present invention is to provide an electrical junction box that can more effectively dissipate heat generated by electronic components when power is applied.

[0010] [Effects of this disclosure] According to the present disclosure, it is possible to provide an electrical junction box that can more effectively dissipate heat from electronic components that generate heat when power is applied.

[0011] [Description of the embodiment of the present invention] First, embodiments of the present disclosure will be listed and described. At least some of the embodiments described below may be combined in any desired manner.

[0012] (1) An electrical connection box according to an embodiment of the present disclosure includes a housing that houses a plurality of bus bars and dissipates heat from the bus bars to the outside through the housing. The electrical connection box includes a first heat dissipation section that is located at a first distance or less from the bus bars and dissipates heat by radiation, and a second heat dissipation section that is located at a second distance or more from the bus bars and dissipates heat by convection.

[0013] In this embodiment, a first heat dissipation section that dissipates heat by radiation and a second heat dissipation section that dissipates heat by convection are provided, and by appropriately combining the first heat dissipation section and the second heat dissipation section to dissipate heat, heat from electronic components can be dissipated more effectively through the bus bar.

[0014] (2) In the electrical junction box according to the embodiment of the present disclosure, the emissivity of the housing is greater than the emissivity of the bus bar.

[0015] In this embodiment, since the emissivity of the housing is greater than the emissivity of the bus bar, the first heat dissipation section and the second heat dissipation section are used to dissipate heat from the bus bar to the outside through the housing, thereby enabling efficient heat dissipation of the electronic components.

[0016] (3) In the electric junction box according to the embodiment of the present disclosure, one surface of the first heat dissipation portion faces the bus bar, and the other surface is exposed to the outside air.

[0017] In this embodiment, one surface of the first heat dissipation portion faces the bus bar, and the other surface is open to the outside air, so that the effect of heat dissipation by radiation can be improved.

[0018] (4) In the electrical junction box according to the embodiment of the present disclosure, the second heat dissipation portion has a through hole.

[0019] In this embodiment, the second heat dissipation portion has a through hole, so that air can enter and exit the housing through the through hole, thereby enhancing the effect of heat dissipation by convection.

[0020] (5) In the electrical junction box according to the embodiment of the present disclosure, a fixing member for fixing the bus bar to another component protrudes from a position facing the through hole.

[0021] In this embodiment, a fixing member for fixing the bus bar to other components protrudes from a position opposite the through hole of the second heat dissipation section, creating a gap between the second heat dissipation section and the wall of the housing, which allows air to flow easily and enables efficient heat dissipation by the second heat dissipation section.

[0022] (6) An electrical connection box according to an embodiment of the present disclosure includes a fixed wall that is fixed to an object, and the plurality of bus bars include one bus bar that has one main surface facing a side wall that intersects with the fixed wall and extends along the side wall, and the side wall has the second heat dissipation portion at a position facing the end of the one bus bar from which the fixing member protrudes, and the first heat dissipation portion at a position facing the other part of the one bus bar excluding the end.

[0023] In this embodiment, the second heat dissipation portion dissipates heat by convection from the end portion of the bus bar from which the fixing member protrudes, and the first heat dissipation portion dissipates heat by radiation from the other portion of the bus bar excluding the end portion. In this manner, by dissipating heat from the bus bar by appropriately combining the first heat dissipation portion and the second heat dissipation portion, heat from electronic components can be dissipated more effectively.

[0024] (7) In the electrical junction box according to the embodiment of the present disclosure, the first heat dissipation portion is provided on the other main surface side of the other portion.

[0025] In this embodiment, the first heat dissipation portions are provided on both main surfaces of the other portion of the bus bar, respectively, and dissipate heat by radiation, thereby further enhancing the heat dissipation effect of the first heat dissipation portions.

[0026] (8) In an electrical connection box according to an embodiment of the present disclosure, the plurality of bus bars include another bus bar including a flat portion having a surface facing the fixed wall, the fixed wall has the first heat dissipation portion at a position facing the facing surface of the flat portion, the fixing member protrudes from the surface opposite the facing surface of the flat portion, and the second heat dissipation portion is provided on the opposite surface side.

[0027] In this embodiment, the first heat dissipation portion dissipates heat by radiation from the opposing surface of the flat portion of the other bus bar, and the second heat dissipation portion dissipates heat by convection from the opposite surface of the flat portion of the other bus bar. In this way, by dissipating heat from the other bus bar by appropriately combining the first heat dissipation portion and the second heat dissipation portion, heat from electronic components can be dissipated more effectively.

[0028] (9) In the electrical junction box according to the embodiment of the present disclosure, the first gap is smaller than the second gap.

[0029] In this embodiment, when the distance to the bus bar is equal to or less than the first distance, the first heat dissipation portion dissipates heat by radiation, and when the distance to the bus bar is wider than the first distance, i.e., equal to or greater than the second distance, the second heat dissipation portion dissipates heat by convection, thereby more effectively dissipating heat from electronic components.

[0030] [Details of the embodiment of the present invention] An electrical junction box according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0031] Fig. 1 is a perspective view of the electrical junction box 100 according to this embodiment, Fig. 2 is a plan view of the electrical junction box 100 according to this embodiment, and Fig. 3 is a bottom view of the electrical junction box 100 according to this embodiment. In Fig. 2 and Fig. 3, the position of a bus bar 10, which will be described later, is indicated by a dashed line.

[0032] The electrical junction box 100 is attached to the outside of an object to be attached, such as a battery pack 500 of an EV (Electric Vehicle). For convenience, Fig. 1 shows the electrical junction box 100 attached to the battery pack 500.

[0033] The electrical junction box 100 includes a housing 50 that houses, for example, at least one relay 40A, a circuit board, etc. The housing 50 has a generally rectangular shape in a plan view, and is made of, for example, a material (for example, resin) having a higher emissivity than the bus bar 10 described below.

[0034] The housing 50 includes a lower case 30 that is attached to the mounting target, and an upper case 20 that partially covers the lower case 30. Electronic components such as a relay 40A and a bus bar 10 are attached to the lower case 30, and the upper case 20 covers a portion of these electronic components. For convenience of explanation, the upper case 20 side will be referred to as the top and the lower case 30 side as the bottom.

[0035] Figure 4 is a plan view showing the electrical junction box 100 of this embodiment with the upper case 20 removed, and Figure 5 is an oblique view showing the electrical junction box 100 of this embodiment with the upper case 20 removed.

[0036] The lower case 30 has a flat box shape with one side facing the upper case 20 being open. The lower case 30 has a substantially rectangular bottom wall 31 (fixed wall) whose outer surface is fixed to the mounting object, and side walls 33 extend perpendicularly from the edges of the bottom wall 31 toward the upper case 20. Steps are formed on both ends of the bottom wall 31, with the ends positioned higher than the middle part. Accordingly, the height of the side walls 33 is shorter at the ends of the bottom wall 31. In addition, ribs 311 are formed in a lattice shape on the outer surface of the bottom wall 31. As described above, the relay 40A and bus bar 10 are provided inside the lower case 30.

[0037] Among the side walls 33 of the lower case 30, the side wall 33 on the long side side of the bottom wall 31 has engaging protrusions 35 protruding from the outer surface thereof at multiple locations to engage with engaging portions 25 (described later) of the upper case 20. The engaging protrusions 35 consist of a pair of protrusions spaced apart in the longitudinal direction of the side wall 33. Furthermore, fixing holes 37 used when attaching the lower case 30 (housing 50) to the attachment target are formed in the bottom wall 31 at the four corners and near one side wall 33. Near the fixing holes 37, notches are formed in the side wall 33.

[0038] 4 and 5, for example, one relay 40A is provided in the lower case 30. The relay 40A has two connection terminals (not shown) facing the side wall 33 on one long side in the width direction of the lower case 30.

[0039] Multiple types of bus bars 10 are provided in lower case 30. These multiple types of bus bars 10 include bus bar 10A (one bus bar) and bus bar 10B connected to the connection terminals of relay 40A, bus bar 10C (another bus bar) provided at one end of lower case 30, and bus bar 10D and bus bar 10E provided at the other end of lower case 30. Bus bar 10A, bus bar 10B, bus bar 10C, bus bar 10D, and bus bar 10E are made of a material (e.g., copper) whose emissivity is lower than that of lower case 30 (housing 50).

[0040] Bus bar 10A and bus bar 10B are disposed near side wall 33 on one long side of lower case 30. Bus bar 10A and bus bar 10B are disposed such that one main surface of each faces side wall 33 on one long side. In other words, bus bar 10A and bus bar 10B are disposed vertically to bottom wall 31.

[0041] Busbar 10A has a rectangular plate shape and extends along sidewall 33 on one long side. Busbar 10A has a step formed near one end 101A in the longitudinal direction, forming a crank shape in a plan view. Busbar 10A is disposed such that other portion 102A excluding one end 101A is closer to sidewall 33 on one long side than one end 101A. One end 101A of busbar 10A is fastened by a screw 200 (fixing member) to one of the two connection terminals of relay 40A, which is closer to the other end of lower case 30 (another component). Screw 200 protrudes from one surface of busbar 10A (one end 101A) facing sidewall 33 on one long side.

[0042] Bus bar 10B has a rectangular plate shape and extends along one long sidewall 33. One end of bus bar 10B is fastened with screw 200 to one of the two connection terminals of relay 40A that is closer to one end of lower case 30.

[0043] Fig. 6 is a vertical cross-sectional view taken along line VI-VI in Fig. 2. Fig. 6 shows the configuration of one end of the lower case 30. Bus bar 10C is provided at one end of lower case 30. Bus bar 10C is made of a plate material and has a flat portion 101C arranged opposite bottom wall 31, with one edge of flat portion 101C bent toward bottom wall 31. That is, flat portion 101C has an opposing surface 103C that faces bottom wall 31. A portion of flat portion 101C corresponding to fixing hole 37 in the vertical direction is cut out.

[0044] Bus bar 10C is fastened to bottom wall 31 by screws 200 via intervening member 312. At this time, the distance between opposing surface 103C and bottom wall 31 is 1 mm or less. Furthermore, at the center of flat portion 101C, screws 200 protrude from opposite surface 102C opposite opposing surface 103C. Opposite surface 102C faces ceiling wall 21B (see FIGS. 1 and 2) of upper case 20, which will be described later.

[0045] Bus bar 10D and bus bar 10E are provided at the other end of lower case 30. Bus bar 10D has a rectangular plate shape, and bus bar 10E has a plate shape, and bus bar 10D and bus bar 10E are arranged opposite bottom wall 31. Bus bar 10D and bus bar 10E partially overlap in the vertical direction, and bus bar 10E is provided below bus bar 10D, i.e., on the bottom wall 31 side. Portions of bus bar 10E corresponding to fixing holes 37 in the vertical direction are cut out.

[0046] Busbar 10D and busbar 10E are fastened to bottom wall 31 with screws 200, which protrude from the upper surface of busbar 10D. In this case, the distance between the lower surfaces of busbar 10D and busbar 10E and bottom wall 31 is 1 mm or less. The upper surface of busbar 10D is exposed to the outside air, and the upper surface of busbar 10E is partially exposed (see FIGS. 1 and 2).

[0047] The upper case 20 has a box shape with one side open facing the lower case 30. The upper case 20 partially covers the lower case 30, and as described above, the bus bars 10D, 10E, etc. at the other end of the lower case 30 are exposed to the outside (see FIGS. 1 and 2).

[0048] The upper case 20 has a ceiling wall 21 facing the bottom wall 31, and side walls 22 extend perpendicularly from the edges of the ceiling wall 21 toward the lower case 30. A step is formed in the ceiling wall 21. That is, in the portion of the ceiling wall 21 corresponding to the relay 40A, i.e., the portion covering the relay 40A (hereinafter referred to as the ceiling wall 21A), steps are formed at one end side (hereinafter referred to as the ceiling wall 21B) and the other end side (hereinafter referred to as the ceiling wall 21C) in the length direction of the lower case 30. Therefore, the ceiling walls 21B and 21C are located lower than the ceiling wall 21A.

[0049] The side walls 22 extend in the length direction of the lower case 30, and as described above, the top walls 21A and 21B are located at different positions in the vertical direction, so the height of the side walls 22 varies depending on the location. The width of the upper case 20 is slightly smaller than the width of the lower case 30, and the side walls 22 face the side walls 33 of the lower case 30 and abut against the inner surfaces of the side walls 33 (see FIG. 7). In this case, the side walls 22 are interposed between the bus bars 10A and 10B and the side walls 33 of the lower case 30.

[0050] A plurality of through-holes are formed in the ceiling wall 21A, and the relay 40A is partially exposed through these through-holes. A plurality of side-wall through-holes 24 are formed in the side wall 22 associated with the ceiling wall 21A. The plurality of side-wall through-holes 24 are formed at predetermined intervals in the longitudinal direction of the lower case 30. Each side-wall through-hole 24 extends in the vertical direction, from the upper end of the side wall 22 to the edge of the ceiling wall 21A. The side-wall through-hole 24 has a width of, for example, several millimeters, so that the fingertips of a person handling it cannot fit through it.

[0051] More specifically, sidewall through-holes 24 are formed at positions facing the connection portions of busbars 10B and 10A with relay 40A. That is, screws 200 for fixing busbars 10B and 10A to connection terminals of relay 40A protrude from busbars 10B and 10A at positions facing sidewall through-holes 24 (see FIG. 4). In this case, the distance from the connection portions of busbars 10B and 10A to sidewall 22 is 5 mm.

[0052] A plurality of top wall through-holes 23 are formed in the top wall 21B, and the bus bar 10C is partially exposed through the top wall through-holes 23. More specifically, a plurality of rows of the top wall through-holes 23 are formed in the length direction of the lower case 30, and these rows are arranged in the width direction of the lower case 30. The center of the top wall 21B protrudes upward (see FIGS. 1 and 2). The top wall through-holes 23 have a width of, for example, several millimeters, such that the fingertips of a person handling them cannot fit through them.

[0053] Furthermore, ceiling wall 21B faces flat portion 101C of bus bar 10C. As described above, screws 200 for fixing bus bar 10C to bottom wall 31 protrude from opposite surface 102C of flat portion 101C, and top wall through-holes 23 of ceiling wall 21B face screws 200. In this case, the distance from opposite surface 102C of bus bar 10C to ceiling wall 21B is 5 mm.

[0054] The ceiling wall 21C has a flat portion and a protruding portion 211C that is provided near the side wall 22 and stands up vertically.

[0055] FIG. 7 is a vertical cross-sectional view taken along line VII-VII in FIG. Protruding portion 211C is disposed near sidewall 22, in other words, near busbar 10A. Protruding portion 211C has cover portion 213C that covers the other main surface of other portion 102A of busbar 10A.

[0056] The cover portion 213C has the flat portion of the ceiling wall 21C connected to a surface opposite to the other main surface of the other portion 102A.

[0057] The cover portion 213C is a generally rectangular shape extending in the length direction of the lower case 30 and has an inverted L-shape in vertical cross section. That is, most of the cover portion 213C is a flat plate portion that faces the other main surface of the bus bar 10A (other portion 102A), and the upper edge of this flat plate portion is bent toward the bus bar 10A. The side wall 22 is connected to the upper edge of the cover portion 213C. The upper end of the cover portion 213C is at the same position as the upper surface of the ceiling wall 21A in the vertical direction. Hereinafter, for convenience, the flat plate portion of the cover portion 213C will also be referred to as the cover portion 213C.

[0058] Cover portion 213C faces busbar 10A (other portion 102A) and sidewall 22 at a predetermined distance. Busbar 10A (other portion 102A) is interposed between cover portion 213C and sidewall 22. That is, sidewall 22 faces one main surface of busbar 10A (other portion 102A), and cover portion 213C faces the other main surface of busbar 10A (other portion 102A).

[0059] 7, the outer surface of the lower end of the side wall 22 contacts the inner surface of the side wall 33 of the lower case 30. As described above, the side wall 33 of the lower case 30 also faces one main surface of the bus bar 10A (other part 102A).

[0060] The distance from side wall 22 to bus bar 10A, the distance from cover portion 213C to bus bar 10A, and the distance from side wall 33 of lower case 30 to bus bar 10A are all 1 mm or less.

[0061] Additionally, the side walls 22 of the upper case 20 are provided with engagement portions 25 at multiple locations on the lower end for engagement with engagement protrusions 35 of the lower case 30. The engagement portions 25 are U-shaped, with both open end portions fixed to the side walls 22 and curved portions projecting downward from the side walls 22. When assembling the upper case 20 and the lower case 30, the engagement protrusions 35 of the lower case 30 pass from the inside of the engagement portions 25 between the edges of the side walls 22 and the curved portions of the engagement portions 25, thereby engaging the engagement protrusions 35 with the engagement portions 25 (see FIG. 1).

[0062] In the electrical junction box 100, when current is applied, heat is generated from the relay 40A and other components, and the heat from the relay 40A is immediately transferred to the bus bar 10 to which it is in direct contact. The heat generated by the relay 40A may adversely affect the electronic components around the relay 40A and the bus bar 10, so it is necessary to cool it quickly. However, the heat dissipation effect from the relay 40A itself cannot be expected to be significant, and heat dissipation via the bus bar 10 connected to the relay 40A is more efficient.

[0063] The electrical connection box 100 of this embodiment is equipped with a first heat dissipation section 70 and a second heat dissipation section 60, which have different heat dissipation mechanisms, and by appropriately combining the heat dissipation mechanism associated with the first heat dissipation section 70 and the heat dissipation mechanism associated with the second heat dissipation section 60, the heat generated from the relay 40A is efficiently dissipated through the bus bar 10.

[0064] The first heat dissipation section 70 and the second heat dissipation section 60 are disposed near the bus bar 10. The first heat dissipation section 70 is spaced from the bus bar 10 by a first distance or less, and dissipates heat by radiation, while the second heat dissipation section 60 is spaced from the bus bar 10 by a second distance or more, and dissipates heat by convection. Here, the first distance is smaller than the second distance. For example, the first distance is 1 mm, and the second distance is 5 mm.

[0065] In the electrical junction box 100 of this embodiment, heat is dissipated from the bus bar 10A by radiation from the first heat dissipation section 70 (hereinafter simply referred to as radiation heat dissipation) and by convection from the second heat dissipation section 60 (hereinafter simply referred to as convection heat dissipation). More specifically, convection heat is dissipated from one end 101A of the bus bar 10A by the second heat dissipation section 60, and radiation convection is dissipated from the other end 102A of the bus bar 10A by the first heat dissipation section 70.

[0066] The portion of the side wall 22 of the upper case 20 that faces one end 101A of the bus bar 10A corresponds to the second heat dissipation portion 60. As described above, this portion corresponding to the second heat dissipation portion 60 faces the connection portion between the bus bar 10A and the relay 40A, and because the screw 200 protrudes from this connection portion, the portion corresponding to the second heat dissipation portion 60 and one end 101A of the bus bar 10A are spaced apart by approximately 5 mm, which is wider than the first distance. The portion corresponding to the second heat dissipation portion 60 also has a plurality of side wall through-holes 24.

[0067] Therefore, outside air can flow into and out of housing 50 through sidewall through-holes 24, and because the corresponding portion of second heat dissipation section 60 and one end 101A of busbar 10A are separated by approximately 5 mm, the flow of outside air is facilitated. Therefore, convection occurs due to the flow of outside air, which cools the heat generated at the connection portion of busbar 10A due to connection resistance. This also prevents the fingertips of a person handling busbar 10A from touching busbar 10A.

[0068] Furthermore, the portion of side wall 22 of upper case 20 that faces other portion 102A of busbar 10A and cover portion 213C correspond to first heat dissipation portion 70. Hereinafter, for convenience, the portion of side wall 22 of upper case 20 that faces other portion 102A of busbar 10A and cover portion 213C will be referred to as the portion corresponding to first heat dissipation portion 70.

[0069] As described above, the inner surface of the portion corresponding to first heat dissipation portion 70 faces other portion 102A of busbar 10A, and the outer surface is exposed to the outside air. The portion corresponding to first heat dissipation portion 70 and other portion 102A of busbar 10A are spaced apart by approximately 1 mm.

[0070] Although the narrow gap between the portion corresponding to first heat dissipation portion 70 and the other portion 102A of busbar 10A results in poor airflow, heat radiation is likely to occur, and heat dissipation by radiation is effective and prioritized. Therefore, heat generated at the other portion 102A of busbar 10A is transferred by radiation to the portion corresponding to first heat dissipation portion 70, and is cooled via the outer surface of the portion corresponding to first heat dissipation portion 70.

[0071] In addition, in the electric junction box 100 of this embodiment, the second heat dissipation section 60 dissipates heat by convection to the bus bar 10B. Of the side wall 22 of the upper case 20, the portion facing the connection portion between the bus bar 10B and the relay 40A corresponds to the second heat dissipation portion 60. For convenience, hereinafter, of the side wall 22 of the upper case 20, the portion facing the connection portion between the bus bar 10B and the relay 40A will be referred to as the portion corresponding to the second heat dissipation portion 60.

[0072] As described above, the corresponding portion of second heat dissipation portion 60 faces the connection portion of bus bar 10B, and since screws 200 protrude from the connection portion, the corresponding portion of second heat dissipation portion 60 and bus bar 10B are spaced apart by approximately 5 mm. In addition, the corresponding portion of second heat dissipation portion 60 has a plurality of sidewall through-holes 24.

[0073] Therefore, outside air can flow into and out of housing 50 via sidewall through-holes 24, and the flowing outside air is easy to flow, causing convection due to the flow of outside air, which cools down the heat generated at the connection portion of busbar 10B due to connection resistance. It is also possible to prevent the fingertips of a person handling busbar 10B from touching busbar 10B.

[0074] Furthermore, in the electrical junction box 100 of this embodiment, the first heat dissipation section 70 performs radiative heat dissipation and the second heat dissipation section 60 performs convective heat dissipation for the bus bar 10C. More specifically, the second heat dissipation section 60 performs convective heat dissipation for the opposite surface 102C of the bus bar 10C, and the first heat dissipation section 70 performs radiative convection for the opposing surface 103C.

[0075] The ceiling wall 21B corresponds to the second heat dissipation section 60. As described above, the second heat dissipation section 60 (ceiling wall 21B) faces the opposite surface 102C of the bus bar 10C, and since the screws 200 protrude from the opposite surface 102C, the second heat dissipation section 60 and the opposite surface 102C of the bus bar 10C are spaced apart by approximately 5 mm. The second heat dissipation section 60 also has a plurality of ceiling wall through-holes 23.

[0076] Therefore, outside air can flow into and out of housing 50 through top wall through-hole 23, and the outside air that flows in can flow easily, thereby cooling the heat generated in bus bar 10C by convection, as described above. This also prevents the fingertips of a person handling bus bar 10C from touching bus bar 10C.

[0077] Furthermore, the portion of bottom wall 31 that faces opposing surface 103C of busbar 10C corresponds to first heat dissipation portion 70. Hereinafter, for convenience, the portion of bottom wall 31 that faces opposing surface 103C of busbar 10C will be referred to as the portion corresponding to first heat dissipation portion 70.

[0078] As described above, the inner surface of the portion corresponding to first heat dissipation portion 70 faces opposing surface 103C of bus bar 10C, and the outer surface is exposed to the outside air. The portion corresponding to first heat dissipation portion 70 and bus bar 10C are spaced apart by approximately 1 mm.

[0079] As described above, the narrow gap between the corresponding portion of first heat dissipation portion 70 and busbar 10C facilitates heat radiation, and heat dissipation by radiation is prioritized. Therefore, heat generated in busbar 10C is transferred by radiation from opposing surface 103C to the corresponding portion of first heat dissipation portion 70, and is cooled via the outer surface of the corresponding portion of first heat dissipation portion 70.

[0080] In the electric junction box 100 of this embodiment, the first heat dissipation section 70 performs radiation heat dissipation to the bus bars 10D, E. More specifically, the first heat dissipation section 70 performs radiation convection to the lower surfaces of the bus bars 10D, E.

[0081] The portions of bottom wall 31 that face the lower surfaces of busbars 10D, E correspond to first heat dissipation portions 70. Hereinafter, for convenience, the portions of bottom wall 31 that face the lower surfaces of busbars 10D, E will be referred to as portions corresponding to first heat dissipation portions 70.

[0082] As described above, the inner surface of the corresponding portion of first heat dissipation portion 70 faces the lower surfaces of bus bars 10D, E, and the outer surface is exposed to the outside air. The corresponding portion of first heat dissipation portion 70 and bus bars 10D, E are spaced apart by approximately 1 mm.

[0083] In this way, heat dissipation by heat radiation is prioritized due to the narrow gap between the corresponding portions of the first heat dissipation portion 70 and the busbars 10D, E. Therefore, the heat generated in the busbars 10D, E is transferred by radiation from the lower surfaces to the corresponding portions of the first heat dissipation portion 70, and is cooled via the outer surfaces of the corresponding portions of the first heat dissipation portion 70.

[0084] As described above, in the electrical junction box 100 of this embodiment, the radiation in the first heat dissipation section 70 and the convection in the second heat dissipation section 60 can be combined appropriately to increase the heat dissipation efficiency of the relay 40A and the bus bar 10.

[0085] The electrical junction box 100 of this embodiment is not limited to the above description, and the housing 50 may be configured to contain an insulating filler (e.g., ceramic oxide). In this case, the insulation properties of the housing 50 can be ensured while increasing thermal conductivity, and the heat dissipation effect of the first heat dissipation section 70 and the second heat dissipation section 60 can be improved.

[0086] The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims, not by the meaning described above, and is intended to include all modifications within the meaning and scope of the claims.

[0087] The matters described in each embodiment can be combined with each other. Furthermore, the independent claims and dependent claims described in the claims can be combined with each other in any combination, regardless of the reference format. Furthermore, although the claims use a format in which a claim references two or more other claims (multiple claim format), this is not limited to this format. Multiple claims (multi-multi claims) that reference at least one other multiple claim may also be used. [Explanation of symbols]

[0088] 10, 10A, 10B, 10C, 10D, 10E busbars 20 Upper Case 21, 21A, 21B, 21C Ceiling wall 22 Side wall 23 Ceiling wall through hole 24 Side wall through hole 25 Engagement part 30 Lower Case 31 Bottom wall 33 Side wall 35 Engagement protrusion 37 Fixing hole 40A relay 50 cabinets 60 Second heat dissipation section 70 1st heat dissipation section 100 Electrical junction box 101A One end 101C Flat part 102A Other parts 102C opposite side 103C Opposite surface 200 screws 211C Protrusion 213C Cover 311 Rib 312 Intervening member 500 battery packs

Claims

1. An electrical connection box including a housing that accommodates a plurality of bus bars, and that dissipates heat from the bus bars to the outside through the housing, a first heat dissipation portion that is provided at a first distance or less from the bus bar and dissipates heat by radiation; and a second heat dissipation section that is spaced apart from the bus bar by a second distance or more and dissipates heat by convection.

2. The electrical junction box according to claim 1 , wherein the emissivity of the housing is greater than the emissivity of the bus bars.

3. 3. The electrical junction box according to claim 1, wherein one surface of the first heat dissipation portion faces the bus bar and the other surface is exposed to the outside air.

4. 3. The electrical junction box according to claim 1, wherein the second heat dissipation portion has a through hole.

5. 5. The electrical junction box according to claim 4, wherein a fixing member for fixing the bus bar to another component projects from a position facing the through hole.

6. A fixed wall is provided to be fixed to the object; the plurality of bus bars include one bus bar having one main surface facing a side wall that intersects with the fixed wall and extending along the side wall, 6. The electrical connection box according to claim 5, wherein the side wall has the second heat dissipation portion at a position facing the end of the one bus bar from which the fixing member protrudes, and the first heat dissipation portion at a position facing the other portion of the one bus bar excluding the end.

7. 7. The electrical junction box according to claim 6, wherein the first heat dissipation portion is provided on the other main surface side of the other portion.

8. the plurality of bus bars includes another bus bar including a flat portion having a surface facing the fixed wall, the fixed wall has the first heat dissipation portion at a position facing the facing surface of the flat portion, 7. The electrical junction box according to claim 6, wherein the fixing member protrudes from a surface of the flat portion opposite to the opposing surface, and the second heat dissipation portion is provided on the opposite surface side.

9. 2. The electrical junction box according to claim 1, wherein the first gap is smaller than the second gap.

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