Electrical distribution box

Abstract

Electrical distribution box (10, 100) arranged between a power supply and a load, the electrical distribution box (10, 100) comprising: a housing (20) which has an opening; a circuit arrangement (30) arranged to close the opening of the housing (20); and a liquid coolant (R) stored in the housing (20), wherein the circuit arrangement (30) has a housing-facing surface (41F) which faces the housing (20), and the circuit arrangement (30) has a busbar (80) which is arranged on the housing-facing surface (41F) and forms a conductor path between the power supply and the load, and the busbar (80) is immersed in the liquid coolant (R).

Description

Technical field

[0001] The technology disclosed in the present description relates to an electrical distribution box. General state of the art

[0002] Vehicles such as electric and hybrid cars contain a battery module that serves as a power source. This battery module consists of numerous individual cells and supplies power to a load, such as a motor. An electrical distribution box, which switches the power supplied to the load on and off, is connected to the battery module.

[0003] DE 196 45 636 C1 discloses a power module for controlling electric motors, consisting of: - a power unit comprising a circuit arrangement comprising power semiconductor components located on the top side of a substrate, - a cooling unit through which a cooling medium flows, which has a heat sink designed as an insert part with a structured surface, onto which the underside of the substrate is directly applied, - a control unit with semiconductor components arranged on a carrier body, which is arranged parallel and spaced apart from the substrate of the power unit, - Contact pins between the substrate of the power unit and the carrier body of the control unit for connecting and contacting the circuit arrangement of the power unit with the semiconductor components of the control unit, - a housing body that encloses the power unit and the control unit, - two busbars leading outwards through the housing body, parallel to the substrate of the power unit and to the carrier body of the control unit, to supply the circuit arrangement of the power unit, - Connection rails extending perpendicularly from the housing body to the substrate of the power unit and to the carrier body of the control unit, connected to the circuit arrangement of the power unit and / or the semiconductor components of the control unit for applying control signals to control the power module and / or for tapping output signals of the power module.

[0004] DE 10 2013 215 913 A1 discloses a high-voltage diode rectifier for an offshore rectifier station with an AC input into which a highly transformed high-voltage AC current generated in an offshore wind farm can be fed. The high-voltage diode rectifier has a DC output from which high-voltage DC current can be fed into a high-voltage DC transmission line for transmitting electrical energy from the rectifier station to an onshore power supply network. Furthermore, the high-voltage diode rectifier has diode valves arranged in a six-pulse bridge circuit between the AC input and the DC output, each of which has several diode stages connected in series, each with at least one diode. The diode valves are arranged in at least one tank filled with a dielectric coolant.The dielectric coolant has a boiling point precisely calculated so that it boils upon contact with the diode valves, which heat up during operation, thus cooling them. Such a high-voltage diode rectifier is high-voltage resistant and particularly compact.

[0005] JP 2011-88598A discloses an inverter unit and a motor powered by high-voltage batteries. Relays are arranged between the high-voltage batteries and the inverter. An electronic control unit (ECU) is connected to both ends of the relay coils and controls the relays by regulating the current flowing through the relay coils. A service connector is detachably located between the cells that make up the high-voltage batteries. Disconnecting the service connector interrupts the power supply from the high-voltage batteries to the inverter and motor, and connecting the service connector enables the power supply from the high-voltage batteries to the inverter and motor. Disconnecting the service connector also deactivates an interlock switch, and connecting the service connector activates the interlock switch.The interlock switch is located between the control unit and the relay coils. Summary of the invention; Technical task

[0006] Electric and hybrid cars have recently required a relatively high current flow. The higher the current, the greater the amount of heat generated in the electrical distribution box.

[0007] To reduce the amount of heat generated, it is conceivable to decrease the electrical resistance of a conductive element within the electrical distribution box. Increasing the cross-sectional area of ​​the conductive element is one possible way to reduce its resistance. However, simply increasing the cross-sectional area of ​​the conductive element would increase the overall size of the electrical distribution box and is therefore impractical. Effective cooling of the electrical distribution box while current is flowing is thus desirable. Solution to the task

[0008] An electrical distribution box disclosed in the present description is designed for arrangement between a power supply and a load and comprises: a housing having an opening; a circuit arrangement arranged to close the opening of the housing; and a liquid coolant stored in the housing, wherein the circuit arrangement has a housing-facing surface facing the housing and a busbar arranged on the housing-facing surface forming a conduit between the power supply and the load, and the busbar is immersed in the liquid coolant.

[0009] In the electrical distribution box, a relatively high current flows through the busbar, which forms the conductor path between the power supply and the load, and consequently, a relatively large amount of heat is generated by the busbar. Since the busbar is immersed in the liquid coolant, the heat generated by the busbar when current flows is transferred to the liquid coolant using the design described above. This allows the busbar to be effectively cooled, and therefore, the electrical distribution box in which the busbar is located can also be effectively cooled.Furthermore, of the elements incorporated in the circuit arrangement, an element that generates a relatively small amount of heat can be located on a surface of the circuit arrangement on the side opposite the housing, and therefore the size of the housing and the amount of liquid coolant can be adjusted to the minimum necessary size and quantity.

[0010] In the above-described design, it is also possible that the circuit arrangement includes a relay that has a terminal, the terminal has a contact section connected to the busbar, and the contact section is immersed in the liquid coolant.

[0011] Since the contact section, which generates a relatively large amount of heat, is immersed in the liquid coolant, this design transfers the heat generated by the contact section when current flows to the liquid coolant. This allows the electrical distribution box, in which the relay is located, to be effectively cooled.

[0012] In the above-described configuration, it is also possible that the circuit arrangement includes a main relay as well as a pre-charge relay and a pre-charge resistor, which are connected in parallel with the main relay and form a pre-charge circuit, and that the pre-charge resistor is immersed in the liquid coolant.

[0013] Since the pre-charge resistor, which generates a relatively large amount of heat, is immersed in the liquid coolant, the heat generated by the pre-charge resistor when current flows is transferred to the liquid coolant in this design. This allows the electrical distribution box in which the pre-charge resistor is located to be effectively cooled.

[0014] In the design described above, it is also possible for the housing to have an inlet through which the liquid coolant can flow into the housing and an outlet through which the liquid coolant can flow out of the housing.

[0015] This design allows the cooled liquid coolant to flow into the housing through the inlet, and the coolant, whose temperature has increased due to heat absorption, to flow out of the housing through the outlet. This improves the cooling efficiency of the electrical distribution box.

[0016] In the design described above, it is also possible that the housing has a heat sink that is in contact with the liquid coolant.

[0017] This design allows the heat absorbed by the liquid coolant to be effectively dissipated via the heat sink. This improves the cooling efficiency of the electrical distribution box. Advantageous effects of the invention

[0018] According to the technology disclosed in the present description, an electrical distribution box can be effectively cooled. Brief description of the drawings Fig. Figure 1 is a first perspective view of an electrical distribution box of embodiment 1. Fig. Figure 2 is a second perspective view of the electrical distribution box. Fig. Figure 3 is a perspective exploded view of the electrical distribution box. Fig. Figure 4 is a top view of the electrical distribution box. Fig. Figure 5 is a perspective view of a cooling housing. Fig. Figure 6 is a perspective view of a circuit arrangement. Fig. Figure 7 is a view of the circuit arrangement from below. Fig. Figure 8 is a perspective view of a circuit board. Fig. Figure 9 is a cross-sectional view along line AA in Fig. 4. Fig. Figure 10 is a cross-sectional view along line BB in Fig. 4. Fig. Figure 11 is an enlarged view of an area in a circle R1. Fig. 9. Fig. Figure 12 is an enlarged view of an area in a circle R2. Fig. 9. Fig. Figure 13 is a perspective view showing a state in which a radiator, a storage tank and a pump are connected to the electrical distribution box. Fig. Figure 14 is a perspective view showing a state in which an electrical distribution box of embodiment 2 is attached to a vehicle body. Fig. Figure 15 is a perspective view showing a circuit arrangement and a cooling housing of the electrical distribution box separately. Fig. Figure 16 is a perspective exploded view of the electrical distribution box. Description of embodiments Embodiment 1

[0019] embodiment 1 is described with reference to Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12 to Fig. 13 described. An electrical distribution box 10 of the present embodiment is a device installed in a vehicle (not shown), such as an electric car or a hybrid car, which switches on / off the power supplied from a power supply to a load, which is not shown. As described in Fig. As shown in Figure 1, the electrical distribution box 10 has a cooling housing 20 (corresponding to a housing) and a circuit arrangement 30 which is attached to the cooling housing 20. A liquid coolant R is stored in the cooling housing 20. Cooling housing 20

[0020] The cooling housing 20 is made of an insulating synthetic resin and, as shown in Fig. Figure 5 shows a housing body 21, an inlet pipe 25P, and an outlet pipe 26P connected to the housing body 21. The housing body 21 has a substantially rectangular bottom wall 22 and a circumferential wall 23 extending perpendicularly to the bottom wall 22 from an outer circumferential edge of the bottom wall 22, forming a right-angled container with an opening 24 on the side opposite the bottom wall 22. In the following description, the two wall sections of the circumferential wall 23 extending from the two long sides of the bottom wall 22 are referred to as long side walls 23L, and the two wall sections extending from the two short sides of the bottom wall 22 are referred to as short side walls 23S1 and 23S2.

[0021] As in Fig. 5 and Fig. As shown in Figure 9, one of the two short sidewalls 23S1 and 23S2 has an inlet 25 extending through this short sidewall 23S1 from an outer surface to an inner surface, and the inlet pipe 25P, which has a tubular shape, is inserted into the inlet 25. The other short sidewall 23S2 has an outlet 26 extending through this short sidewall 23S2 from an outer surface to an inner surface, and the outlet pipe 26P, which has a tubular shape, is inserted into the outlet 26.

[0022] As in Fig. As shown in Figure 11, the circumferential wall 23 has a support surface 27 that supports the circuit arrangement 30. The support surface 27 is a surface formed by cutting into the edge of the opening 24 and is parallel to the bottom wall 22. The support surface 27 has a sealing groove 28. The sealing groove 28 is a recess cut into the support surface 27 towards the bottom wall 22, and a sealing ring S1 is received in the sealing groove 28 in a state where it protrudes slightly from the sealing groove 28. The sealing ring S1 is a rectangular, frame-shaped element formed from an elastic element made of rubber or the like.

[0023] The liquid coolant R, which has insulating properties, is stored in the cooling housing 20. For example, one or more coolants can be used as the liquid coolant R, selected from the group consisting of perfluorocarbons, hydrofluoroethers, hydrofluoroketones, fluorinert fluids, oils such as silicone oil and mineral oil, and hydrocarbon-based coolants. Fig. 9, Fig. 10, Fig. 11 and Fig. Figure 12 shows the liquid coolant R as hatched.

[0024] As in Fig. As shown in Figure 13, a radiator 91, a storage tank 92 and a pump 93, which have known designs, can be connected to the electrical distribution box 10 via connecting pipes 90, which are connected to the inlet pipe 25P and the outlet pipe 26P, and the liquid coolant R, which has been cooled by the radiator 91, can be circulated through the cooling housing 20. Circuit arrangement 30

[0025] As in Fig. 9 and Fig. As shown in Figure 10, the circuit arrangement 30 is an element arranged such that it closes the opening 24 of the cooling housing 20. As shown in Fig. As shown in Figure 3, the circuit arrangement 30 comprises: a circuit board 40, a plurality of busbars 80A, 80B, 80C, 80D and 80E which are attached to the circuit board 40 and form a path between a power supply and a load, two main relays 50B and 50C (corresponding to one relay), as well as a pre-charge relay 50A (corresponding to the relay) and a pre-charge resistor 70 which are connected in parallel with the two main relays 50B and 50C and form a pre-charge circuit. Circuit board 40

[0026] The circuit board 40 is made of a synthetic resin and features, as in Fig. Figure 8 shows a rectangular, plate-shaped main plate 41, three relay holding sections 42A, 42B and 42C positioned on the main plate 41, and four connectors 48A, 48B, 48C and 48D. As shown in Fig. 9 and Fig. As shown in Figure 10, the main plate 41 is arranged such that it closes the opening 24 of the cooling housing 20, and a circumferential edge section thereof is supported by the support surface 27. As shown in Fig. Figure 11 shows a design in which a gap between the cooling housing 20 and the circuit board 40 is sealed liquid-tight by clamping the sealing ring S1 between an inner wall of the sealing groove 28 and the main plate 41. A surface of the main plate 41 forms a housing-facing surface 41F, which faces the cooling housing 20.

[0027] The first relay holding section 42A, the second relay holding section 42B and the third relay holding section 42C are in Fig. The 9 relay holding sections are positioned in this order from the right. The second relay holding section 42B and the third relay holding section 42C have the same configuration as the first relay holding section 42A, except that they are larger than the first relay holding section 42A. For this reason, the first relay holding section 42A is described in detail below, and a description of the second relay holding section 42B and the third relay holding section 42C is omitted, with components of these that are identical to the components of the first relay holding section 42A being designated with the same reference numerals.

[0028] The first relay holding section 42A has a relay holding tube 43, a relay holding wall 44 and two relay fixing columns 45.

[0029] As in Fig. 8 and Fig. As shown in Figure 12, the relay retaining tube 43 is a right-angled, tubular section that opens at both ends and is arranged extending through the main plate 41, with one end section projecting slightly from the circuit board 40 towards the cooling housing 20, while the other, larger section extends towards the side opposite the cooling housing 20. As shown in Fig. As shown in Figure 12, the relay retaining wall 44 is a plate-shaped, wall-like section that extends inwards from an opening edge of the relay retaining tube 43 facing the cooling housing 20 and is perpendicular to the relay retaining tube 43. As shown in Fig. As shown in Figure 8, each of the two relay fixing columns 45 is a column-shaped section arranged adjacent to the relay retaining tube 43 and extending from the main plate 41 to the side opposite the cooling housing 20, and has in its end section on the side opposite the main plate 41 a nut receiving section 46 which receives a nut (not shown) and a screw insertion hole 47 into which a screw B can be inserted.

[0030] Two of the four connectors 48A, 48B, 48C and 48D form a first positive electrode connector 48A and a first negative electrode connector 48B for connection to the power supply and are positioned side by side on an end section of the main plate 41, as shown in Fig. 4 shown. The other two connectors form a second positive electrode connector 48C and a second negative electrode connector 48D for connection to the load and are positioned side by side on the side opposite the first positive electrode connector 48A and the first negative electrode connector 48B via the three relay holding sections 42A, 42B and 42C. Relays 50A, 50B and 50C

[0031] The pre-charge relay 50A, held by the first relay holding section 42A, the positive electrode main relay 50B, held by the second relay holding section 42B, and the negative electrode main relay 50C, held by the third relay holding section 42C, are in Fig. The 9 components are positioned in this order from the right. The positive electrode main relay 50B and the negative electrode main relay 50C have the same design as the pre-charge relay 50A, except that they are larger. For this reason, the pre-charge relay 50A is described in detail below, and a description of the positive electrode main relay 50B and the negative electrode main relay 50C is omitted, although components of these relays that are identical to those of the pre-charge relay 50A are designated with the same reference numerals.

[0032] As in Fig. As shown in Figure 12, the pre-charge relay 50A comprises: a relay housing 51, two fixed terminals 57 attached to the relay housing 51, and a coil 63 and a movable element 66 contained within the relay housing 51.

[0033] The relay housing 51 is a rectangular housing made of a synthetic resin and has rectangular plate-shaped upper and lower walls 52 and 53, positioned opposite each other, and a rectangular, tubular circumferential wall 54 that connects the upper wall 52 and the lower wall 53. As shown in Fig. As shown in Figure 3, two fastening pieces 55 extend from the upper wall 52. The two fastening pieces 55 are each a right-angled, plate-like section and extend from a circumferential edge of the upper wall 52, so that they are flush with the upper wall 52.

[0034] The two fixed terminals 57 are each a cylindrical element made of metal and are arranged extending through the lower wall 53. A seal P1, formed from an elastic element of rubber or the like, is arranged between each fixed terminal 57 and the lower wall 53, and the space between the fixed terminal 57 and the lower wall 53 is sealed liquid-tight by the seal P1. One end section of each fixed terminal 57, which is arranged outside the relay housing 51, forms a busbar contact 58 (corresponding to a contact section) and has a screw hole (not shown) that opens into this busbar contact 58. The other end section of each fixed terminal 57, which is arranged inside the relay housing 51, forms a fixed contact 59.

[0035] A coil carrier 62 is arranged in the relay housing 51 and is fixed to the upper wall 52 by a base section 61. The coil 63 is formed by winding a metal wire around the coil carrier 62. A core made of magnetic material (not shown) is housed in the coil carrier 62. A projecting shaft section 64 extends from the coil carrier 62 towards the lower wall 53. A magnetic element 65, also made of magnetic material, is fixed to one end section of the projecting shaft section 64.

[0036] The movable element 66 is arranged on a surface of the magnetic element 65 facing the lower wall 53. The movable element 66 is made of a conductive material and can be attracted by the magnetic element 65. On its surface facing the fixed terminals 57, the movable element 66 has two movable contacts 67, each contact 67 being curved into a hemispherical shape. Each of the two movable contacts 67 is arranged opposite one of the two fixed contacts 59. Although not shown in detail, a spring is arranged between the movable element 66 and the magnetic element 65, which biases the movable element 66 towards the fixed terminal 57.The spring force of this spring biases the movable element 66 towards the fixed terminal 57, causing the movable contacts 67 to come into contact with the respective fixed contacts 59. When current flows through the coil 63, the movable element 66 is attracted by the magnetic element 65 through a magnetic force generated by the coil 63 and the core. This breaks the electrical connection between the fixed contacts 59 and the respective movable contacts 67.

[0037] As in Fig. As shown in Figure 6, the pre-charging relay 50A is held by the first relay holding section 42A by the fact that a section of the pre-charging relay 50A adjacent to the lower wall 53 is received in the relay holding tube 43 of the first relay holding section 42A, and the two mounting pieces 55 are each fixed to the two relay fixing columns 45 with the screws B. As shown in Fig. As shown in Figure 12, the lower wall 53 is supported by the relay mounting wall 44. The busbar contact 58 of each of the two fixed terminals 57 projects from the relay mounting wall 44 towards the bottom wall 22 and is therefore in a state where it is located on the housing-facing surface 41F of the circuit board 40. In contrast, the relay housing 51 is located on the side opposite the cooling housing 20 with respect to the main board 41. The entire relay housing 51 is thus located outside the cooling housing 20. A sealing ring S2 is arranged between the relay mounting wall 44 and the lower wall 53, and the gap between the circuit board 40 and the pre-charging relay 50A is sealed liquid-tight by the sealing ring S2.

[0038] Likewise, the positive electrode main relay 50B is held by the second relay holding section 42B and the negative electrode main relay 50C is held by the third relay holding section 42C. Pre-charge resistor 70

[0039] The pre-charge resistor 70 is a resistor located on the housing-facing surface 41F of the circuit board 40 and has a resistor body 71 and two terminal sections 72 extending continuously from the resistor body 71. Busbars 80A, 80B, 80C, 80D and 80E

[0040] The multiple busbars comprise five busbars (first positive electrode busbar 80A, second positive electrode busbar 80B, third positive electrode busbar 80C, first negative electrode busbar 80D, and second negative electrode busbar 80E) arranged on the housing-facing surface 41F of the circuit board 40. As shown in Fig. 3 and Fig. As shown in Figure 7, busbars 80A, 80B, 80C, 80D and 80E are each an elongated, plate-shaped element made of metal, and some of these busbars, namely busbars 80B, 80C and 80D, have curved shapes according to the cable routing.

[0041] As in Fig. As shown in Figure 3, the first positive electrode busbar 80A has an elongated, plate-shaped busbar main body 81A and a connecting section 82A extending perpendicularly to the busbar main body 81A from one end of the busbar main body 81A. As shown in Fig. As shown in Figure 7, the busbar main body 81A rests against one of the busbar contacts 58 of the positive electrode main relay 50B and the busbar contact 58 of one of the fixed terminals 57 of the negative electrode main relay 50C and is fixed thereto with screws B. As shown in Fig. As shown in Figure 4, the connecting section 82A runs through the main plate 41 and is positioned in the first positive electrode connector 48A and fixed to a positive electrode connecting busbar 84 with a screw B. The positive electrode connecting busbar 84 is connected to a positive electrode of the power supply.

[0042] As in Fig. As shown in Figure 3, the second positive electrode busbar 80B has an elongated, plate-shaped busbar main body 81B and a connecting section 82B extending continuously from one end of the busbar main body 81B. As shown in Fig. As shown in Figure 7, the busbar main body 81B rests against the other busbar contact 58 of the negative electrode main relay 50B and is fixed to it with a screw B. The connecting section 82B is fixed with a screw B to one of the connection sections 72 of the pre-charge resistor 70.

[0043] As in Fig. As shown in Figure 3, the third positive electrode busbar 80C comprises: an elongated, plate-shaped busbar main body 81C, a first connecting section 82C extending perpendicularly to the busbar main body 81C from one end of the busbar main body 81C, and a second connecting section 83C extending continuously from a section of the busbar main body 81C located near its other end. As shown in Fig. As shown in Figure 7, the busbar main body 81D rests against one of the busbar contacts 58 of the pre-charge relay 50A and is fixed to it with a screw B. As shown in Fig. As shown in Figure 4, the first connecting section 82C passes through the main plate 41 and is positioned in the second positive electrode connector 48C and is connected to the load. The second connecting section 83C is fixed to the other connecting section 72 of the pre-charge resistor 70 with a screw B.

[0044] As in Fig. As shown in Figure 3, the first negative electrode busbar 80D has an elongated, plate-shaped busbar main body 81D and a connecting section 82D extending perpendicularly to the busbar main body 81D from one end of the busbar main body 81D. As shown in Fig. As shown in Figure 7, the busbar main body 81D rests against one of the busbar contacts 58 of the pre-charge relay 50A and is fixed to it with a screw B. As shown in Fig. As shown in Figure 4, the connecting section 82D runs through the main plate 41 and is positioned in the first negative electrode connector 48B and fixed to a negative electrode connection busbar 85 with a screw B. The negative electrode connection busbar 85 is connected to a negative electrode of the power supply. A current sensor 86 is also attached to the negative electrode busbar 88.

[0045] As in Fig. As shown in Figure 3, the second negative electrode busbar 80E has an elongated, plate-shaped busbar main body 81E and a connecting section 82E extending perpendicularly to the busbar main body 81E from one end of the busbar main body 81E. As shown in Fig. As shown in Figure 7, the main busbar body 81E rests against the other busbar contact 58 of the pre-charge relay 50A and is fixed to it with a screw B. As shown in Fig. As shown in Figure 4, the connecting section 82E passes through the main plate 41 and is positioned in the first negative electrode connector 48D and connected to the load.

[0046] Seals P2, which are formed from elastic elements made of rubber or the like, are arranged between the main plate 41 and the connecting sections 82A, 82C, 82D and 82E, which pass through the main plate 41, and spaces between the main plate 41 and the connecting sections 82A, 82C, 82D and 82E are sealed liquid-tight by the seals P2. Cooling by liquid coolant R

[0047] As in Fig. 9 and Fig. As shown in Figure 10, the entire pre-charge resistor 70 is arranged on the housing-facing surface 41F of the circuit board 40 and immersed in the liquid coolant R. As shown in Fig. As shown in Figure 7, sections of the five busbars 80A, 80B, 80C, 80D and 80E, except for the connecting sections 82A, 82C, 82D and 82E, are arranged on the housing-facing surface 41F of the circuit board 40 for connection to the power supply or the load, and these sections are immersed in the liquid coolant R, as shown in Fig. 9 and Fig. 10 shown.

[0048] Furthermore, the two busbar contacts 58 of the pre-charging relay 50A are immersed in the liquid coolant R. The busbar contacts 58 of the other two relays 50B and 50C are also immersed in the liquid coolant R.

[0049] Heat generated by the busbars 80A, 80B, 80C, 80D and 80E, the pre-charge resistor 70 and the busbar contacts 58 when current flows is transferred to the liquid coolant R. This allows the busbars 80A, 80B, 80C, 80D and 80E, the pre-charge resistor 70 and the busbar contacts 58 to be cooled. Summary

[0050] As described above, according to the present embodiment, the electrical distribution box 10, which is arranged between the power supply and the load, comprises: the cooling housing 20, which has the opening 24, the circuit arrangement 30, which is arranged to close the opening 24 of the cooling housing 20, and the liquid coolant R, which is stored in the cooling housing 20. The circuit arrangement 30 has the housing-facing surface 41F, which faces the cooling housing 20, and has the plurality of busbars 80A, 80B, 80C, 80D and 80E, which are arranged on the housing-facing surface 41F and form the conducting path between the power supply and the load, and sections of the busbars 80A, 80B, 80C, 80D and 80E except for the connecting sections 82A, 82C, 82D and 82E for connection to the power supply or the load are immersed in the liquid coolant R.

[0051] Since a relatively high current flows through busbars 80A, 80B, 80C, 80D, and 80E, which form the path between the power supply and the load, a relatively large amount of heat is generated from these busbars. Because sections of busbars 80A, 80B, 80C, 80D, and 80E, except for the connecting sections 82A, 82C, 82D, and 82E, are immersed in the liquid coolant R, the heat generated by busbars 80A, 80B, 80C, 80D, and 80E when current flows is transferred to the liquid coolant R, according to the present embodiment. Thus, the busbars 80A, 80B, 80C, 80D and 80E can be effectively cooled, and therefore the electrical distribution box 10, in which the busbars 80A, 80B, 80C, 80D and 80E are positioned, can be effectively cooled.Furthermore, since one of the elements 30 incorporated into the circuit arrangement, which generates a relatively small amount of heat, can be located on a surface of the circuit arrangement 30 that is on the side opposite the cooling housing 20, the size of the cooling housing 20 and the quantity of liquid coolant R can be adjusted to the minimum necessary size and quantity. The circuit arrangement 30 also includes three relays 50A, 50B, and 50C, which have fixed terminals 57. Each fixed terminal 57 has a busbar contact 58 that is connected to one of the busbars 80A, 80B, 80C, 80D, and 80E, and the busbar contacts 58 are immersed in the liquid coolant R.

[0052] Since the busbar contacts 58 of each of the three relays 50A, 50B, and 50C, which generate a relatively large amount of heat, are immersed in the liquid coolant R, this design transfers the heat generated by the busbar contacts 58 when current flows to the liquid coolant R. Thus, the electrical distribution box 10, in which the relays 50A, 50B, and 50C are located, can be effectively cooled. Furthermore, the entire relay housing 51 is located outside the cooling enclosure 20. Therefore, the size of the cooling enclosure 20 and the amount of liquid coolant R can be adjusted to the minimum necessary size and quantity.

[0053] Furthermore, the circuit arrangement 30 includes the two main relays 50B and 50C, as well as the pre-charge relay 50A and the pre-charge resistor 70, which are connected in parallel with the main relays 50B and 50C and form a pre-charge circuit, and the pre-charge resistor 70 is immersed in the liquid coolant R.

[0054] With this configuration, the pre-charge resistor 70, which generates a relatively large amount of heat, is immersed in the liquid coolant R, and therefore the heat generated by the pre-charge resistor 70 when current flows is transferred to the liquid coolant R. Thus, the electrical distribution box 10, in which the pre-charge resistor 70 is located, can be effectively cooled.

[0055] Furthermore, the cooling housing has the inlet 25, through which the liquid coolant R can flow into the cooling housing, and the outlet 26, through which the liquid coolant R can flow out of the cooling housing.

[0056] With this design, the cooled liquid coolant R can flow through the inlet 25 into the cooling housing 20, and the liquid coolant R, whose temperature has increased as a result of heat absorption, can flow out of the cooling housing 20 through the outlet 26. This improves the cooling efficiency of the electrical distribution box 10. Design 2

[0057] Next, with reference to Fig. 14, Fig. 15 to Fig. 16. Embodiment 2 is described. An electrical distribution box 100 of embodiment 2 differs from the electrical distribution box of embodiment 1 in that a cooling housing 110 has a heat sink 113 instead of the inlet 25, the outlet 26, the inlet pipe 25P and the outlet pipe 26P. In the following description, components that are the same as in the first embodiment are designated with the same reference numerals, and their description is omitted.

[0058] The cooling housing 110 has a frame 111 and a heat sink 113 fixed to the frame 111. As in Fig. As shown in Figure 16, the frame 111 is a flat, rectangular tubular element that has openings at both ends and is made of an insulating synthetic resin.

[0059] The heat sink 113 is a heat dissipation element made of a metal with very good thermal conductivity. As in Fig. As shown in Figure 16, the heat sink 113 has a closure surface 114 arranged to close an opening 112A from the openings of the frame 111, and a raised bottom section 115 projecting from the closure surface 114. The raised bottom section 115 is a flat, rectangular, projecting section located on a portion of the closure surface 114, except for a portion adjacent to its outer circumferential edge. The opening 24 of the frame 111 is closed because the raised bottom section 115 fits substantially tightly into the opening 112A, and a portion of the closure surface 114 surrounding the raised bottom section 115 abuts the frame 111. As shown in Fig. As shown in Figure 15, a gap between the frame 111 and the closure surface 114 is sealed by a sealing material 116. As with the housing of embodiment 1, the liquid coolant R is stored in an interior of the cooling housing 110, which is surrounded by the frame 111 and the closure surface 114, and the liquid coolant R is in contact with the raised bottom section 115.

[0060] As with the housing of embodiment 1, an opening 112B of the frame 111, located on the side opposite the heat sink 113, is closed by the circuit arrangement 30. Although not shown in detail, as with the housing of embodiment 1, the sections of the five busbars 80A, 80B, 80C, 80D and 80E, except for the connecting sections 82A, 82C, 82D and 82E, the pre-charge resistor 70 and the busbar contacts 5 of the three relays 50A, 50B and 50C, are immersed in the liquid coolant R.

[0061] As in Fig. As shown in Figure 14, the heat sink 113 is arranged such that its surface on the side opposite the closure surface 114 rests against a vehicle body 120.

[0062] The heat generated by the busbars 80A, 80B, 80C, 80D, and 80E, the pre-charge resistor 70, and the busbar contacts 58 when current flows is transferred to the liquid coolant R. This allows the busbars 80A, 80B, 80C, 80D, and 80E, the pre-charge resistor 70, and the busbar contacts 58 to be cooled. The heat transferred to the liquid coolant R is then conducted via the heat sink 113 to the vehicle body 120 and dissipated.

[0063] In the present embodiment, the electrical distribution box 100 can also be effectively cooled, as in the housing of embodiment 1.

[0064] Furthermore, the cooling housing 110 features the heat sink 113, which is in contact with the liquid coolant R. This design allows the heat absorbed by the liquid coolant R to be effectively dissipated via the heat sink 113. This improves the cooling efficiency of the electrical distribution box 100. Other embodiments (1) According to the preceding embodiments, the circuit arrangement comprises the five busbars 80A, 80B, 80C, 80D and 80E and the three relays 50A, 50B and 50C. However, the number of busbars and the number of relays are not limited to those of the preceding embodiments and can be chosen as any desired number. (2) In the preceding embodiments, a design was described in which the pre-charge resistor 70 is immersed in the liquid coolant R. However, the component immersed in the liquid coolant R is not limited to a pre-charge resistor. A design can also be used in which each electronic component that generates a relatively large amount of heat is arranged on a surface of a circuit arrangement facing a housing and is immersed in a liquid coolant. List of reference numbers 10, 100 electrical distribution box 20 cooling housings (cases) 24-hour opening 25 Admission 26 Outlet 30 Circuit arrangement 41F housing-facing surface 50A pre-charging relay (relay) 50B Positive electrode main relay (relay, main relay) 50C Negative Electrode Main Relay (Relay, Main Relay) 57 fixed connection 58 Busbar contact (contact section) 70 pre-charge resistor 80A first positive electrode busbar (busbar) 80B second positive electrode busbar (busbar) 80C third positive electrode current rail (current rail) 80D first negative electrode busbar (busbar) 80E second negative electrode busbar (busbar) 113 Heat sink R liquid coolant

Claims

[1] Electrical distribution box (10, 100) arranged between a power supply and a load, the electrical distribution box (10, 100) comprising: a housing (20) which has an opening; a circuit arrangement (30) arranged to close the opening of the housing (20); and a liquid coolant (R) stored in the housing (20), wherein the circuit arrangement (30) has a housing-facing surface (41F) which faces the housing (20), and the circuit arrangement (30) has a busbar (80) which is arranged on the housing-facing surface (41F) and forms a conductor path between the power supply and the load, and the busbar (80) is immersed in the liquid coolant (R). [2] Electrical distribution box (10, 100) according to claim 1, wherein the circuit arrangement (30) includes a relay (50) which has a terminal (57), the connection (57) has a contact section (58) connected to the busbar (80) and the contact section (58) is immersed in the liquid coolant (R). [3] Electrical distribution box (10, 100) according to claim 1, wherein the circuit arrangement (30) comprises a main relay (50B, 50C) as well as a pre-charge relay (50C) and a pre-charge resistor (70) which are connected in parallel with the main relay (50B, 50C) and form a pre-charge circuit and the pre-charge resistor is immersed in the liquid coolant (R). [4] Electrical distribution box (10, 100) according to one of claims 1 to 3, wherein the housing (20) has an inlet (25) through which the liquid coolant (R) can flow into the housing (20) and an outlet (26) through which the liquid coolant (R) can flow out of the housing (20). [5] Electrical distribution box (10, 100) according to one of claims 1 to 3, wherein the housing (20) has a heat sink (113) which is in contact with the liquid coolant (R).

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