Electric junction box

Abstract

A battery shut-off unit (1) that is an example of this electric junction box comprises: an insulating resin case (10) that is disposed facing a water cooler (60) that is an example of a heat dissipation member; a relay (20) that is disposed in the case (10); a bus bar (30) that is connected to a terminal (21) of the relay (20) and that is fixed to the case (10) by insert molding; and a heat conduction layer (70) that is disposed on the water cooler (60) side of the case (10).

Description

Electrical connection box

[0006]

[0001] The present disclosure relates to an electrical connection box such as a battery disconnect unit.

[0002] Electric vehicles such as hybrid electric vehicles or pure electric vehicles are equipped with a power battery and an electrical connection box for connecting the battery to various electrical devices (Patent Document 1).

[0003] As this type of electrical connection box, a battery disconnect unit (BDU; Battery Disconnect Unit) is known. The battery disconnect unit includes a relay for interrupting or supplying the power output from the battery. For example, the battery disconnect unit includes a resin case, a relay housed in the case, and a bus bar connected to the terminals of the relay.

[0004] Japanese Patent Application Laid-Open No. 2005-210804

[0005] However, in the conventional battery disconnect unit, the connection strength between the terminals (fixed terminals) of the relay and the bus bar is not sufficient. [[ID=X]]

[0006] In addition, heat is generated from the relay, which is a power device, in the battery disconnect unit. However, since the distance from the terminals of the relay to the external radiator is long, it is difficult to sufficiently dissipate the heat generated by the relay. In particular, when a large current is suddenly discharged from the battery during a short-time rapid acceleration of an electric vehicle, the relay becomes hot.

[0007] Moreover, in the battery disconnect unit, it is important to ensure insulation because a large current flows through the bus bar. However, depending on the insulation structure, it becomes an inhibitory factor when dissipating the heat generated by the relay.

[0008] Thus, the conventional battery disconnect unit has a problem that it is difficult to achieve both the connection strength between the relay and the bus bar, heat dissipation, and insulation.

[0009] This disclosure was made to solve these problems and aims to provide an electrical junction box that can achieve both robust connection between relays and busbars, good heat dissipation, and good insulation.

[0010] To achieve the above objective, one embodiment of an electrical junction box according to the present disclosure is an electrical junction box arranged opposite a heat dissipation member, comprising: an insulating resin case; a relay arranged in the case; a busbar connected to the terminals of the relay and fixed to the case by insert molding; and a heat conductive layer arranged on the heat dissipation member side of the case.

[0011] According to this disclosure, it is possible to achieve a combination of robust connection between the relay and the busbar, heat dissipation, and insulation.

[0012] This is a block diagram of a drive system according to an embodiment. This is a perspective view of a battery shut-off unit according to an embodiment. This is an exploded perspective view of a battery shut-off unit according to an embodiment. This is a cross-sectional view of a battery shut-off unit according to an embodiment. This is an enlarged cross-sectional view showing the main part of a battery shut-off unit according to an embodiment. This is a diagram illustrating a method for manufacturing a battery shut-off unit according to an embodiment. This is a diagram showing the configuration of a battery shut-off unit of a comparative example. This is an enlarged cross-sectional view showing the main part of a modified battery shut-off unit. This is a cross-sectional view showing a modified busbar.

[0013] The embodiments of this disclosure will be described below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. Therefore, the numerical values, components, arrangement and connection configurations of components, as well as the processes and their sequences shown in the following embodiments, are examples only and are not intended to limit this disclosure. Accordingly, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0014] Furthermore, each figure is a schematic diagram and not necessarily a strictly accurate representation. In addition, the same reference numerals are used for substantially identical components in each figure, and redundant explanations are omitted or simplified. Moreover, in this specification, the terms "up" and "down" do not necessarily refer to the upward direction (vertically upward) and the downward direction (vertically downward) in absolute spatial perception.

[0015] (Embodiment) First, as an example of a system in which the battery cutoff unit 1 according to the embodiment is used, a drive system 100 will be described. Figure 1 is a block diagram of the drive system 100 according to the embodiment.

[0016] As shown in Figure 1, the drive system 100 comprises a battery cutoff unit 1, a battery 2, and an inverter 3.

[0017] The battery disconnection unit 1 is an example of an electrical connection box for connecting a battery 2 to various electrical devices. For example, the battery disconnection unit 1 is connected between the battery 2 and the inverter 3, and can either disconnect the DC power output from the battery 2 or supply it to the inverter 3. In other words, the battery disconnection unit 1 can switch between a power supply state, which supplies power to the inverter 3, and a power disconnection state, which cuts off power to the inverter 3.

[0018] Although not shown in the diagram, the battery disconnection unit 1 may be connected not only to the inverter 3 but also to the rapid charging circuit. In this case, the battery disconnection unit 1 can switch the output destination of the DC power output from the battery 2 to either the inverter 3 or the rapid charging circuit. The battery disconnection unit 1 can also switch between a power supply state, which supplies power to the rapid charging circuit, and a power disconnection state, which cuts off power to the rapid charging circuit. In addition, as another configuration, the battery disconnection unit 1 may be equipped with a rapid charging circuit.

[0019] Battery 2 is an energy storage device such as a secondary battery. Battery 2 outputs DC power. Therefore, Battery 2 connected to Battery Shutdown Unit 1 supplies DC power to Battery Shutdown Unit 1. Battery 2 is, for example, a lithium-ion secondary battery, but is not limited to this.

[0020] The inverter 3 is an AC / DC converter that converts the DC power supplied from the battery cutoff unit 1 into AC power. Although not shown in the diagram, the inverter 3 is connected to, for example, a motor, and the motor connected to the inverter 3 is driven by the AC power output from the inverter 3.

[0021] The drive system 100 configured in this way is installed in an electric vehicle, such as a hybrid electric vehicle or a pure electric vehicle. In other words, the battery disconnection unit 1 is installed in the electric vehicle together with the battery 2. In this case, the DC power output from the battery 2 is supplied to the inverter 3 via the battery disconnection unit 1 as driving energy for the electric vehicle to run, and is converted into AC power. The AC power output from the inverter 3 is supplied to a motor that rotates the vehicle's wheels.

[0022] Next, the structure of the battery shut-off unit 1 according to the embodiment will be described using Figures 2 to 5. Figure 2 is a perspective view of the battery shut-off unit 1 according to the embodiment. In Figure 2, the upper case 11 is removed. Figure 3 is an exploded perspective view of the battery shut-off unit 1 according to the embodiment. In Figure 3, the upper case 11 is omitted. Figure 4 is a cross-sectional view of the battery shut-off unit 1 according to the embodiment. In Figure 4, basically only the parts that appear in the cross-section are shown. Figure 5 is an enlarged cross-sectional view showing the main part of the battery shut-off unit 1 according to the embodiment. Specifically, Figure 5 is an enlarged cross-sectional view of the region V shown by the dashed line in Figure 4.

[0023] As shown in Figures 2 to 5, the battery shut-off unit 1 comprises a case 10, a relay 20, a busbar 30, a relay cover 40, screws 50, a water cooler 60, and a heat conduction layer 70.

[0024] In addition to the relay 20, the battery cutoff unit 1 may also include other electronic components such as an active fuse (a fuse that is cut off by an external signal, for example, a pyro fuse or pyrotechnic circuit breaker that cuts off the circuit by the explosive force caused by the ignition of explosives based on an external cutoff instruction signal), a current sensor such as a Hall sensor, and a resistor such as a shunt resistor.

[0025] Case 10 is an enclosure for housing components. In this embodiment, case 10 houses the relay 20, the busbar 30, and the relay cover 40. Note that other components are also housed in case 10.

[0026] As shown in Figure 2, the case 10 has an upper case 11 which is a first cover and a lower case 12 which is a second cover. The upper case 11 is assembled to the lower case 12 so as to cover the lower case 12. The components housed in the case 10 are mainly located in the lower case 12. The relay 20 and the busbar 30 are located in the lower case 12. The upper case 11 is the outer casing member of the battery shut-off unit 1.

[0027] As shown in Figures 2 to 4, in this embodiment, the lower case 12 is provided with a relay housing 12a, and the relay 20 is located in the relay housing 12a. As shown in Figures 3 and 4, the relay housing 12a is a recess provided in a part of the lower case 12, and the relay housing 22 of the relay 20 is housed in this recess. Specifically, as shown in Figure 4, the back surface of the relay housing 22 and the bottom surface of the recessed relay housing 12a are in surface contact.

[0028] Furthermore, as shown in Figures 2 and 3, the lower case 12 is provided with a support portion 12b that supports the relay cover 40. The relay cover 40 is attached to the support portion 12b. The support portion 12b is part of the lower case 12 and is formed to protrude toward the upper case 11. Specifically, as shown in Figure 3, the support portion 12b is formed in a cylindrical shape. Multiple support portions 12b are provided for one relay cover 40. In this embodiment, three support portions 12b are provided for one relay cover 40. The three support portions 12b are arranged near the relay housing portion 12a. Specifically, the three support portions 12b are arranged in a triangular layout surrounding the relay housing portion 12a. In this embodiment, since two relay covers 40 are arranged, the lower case 12 is provided with six support portions 12b.

[0029] The busbars 30 are fixed to the case 10 shown in Figures 2 to 4. As will be explained in detail later, among the multiple busbars 30, there are busbars 30 that are fixed to the case 10 by insert molding. In other words, the case 10 is a module case in which the busbars 30 are fixed in advance by insert molding. Specifically, the busbars 30 are fixed to the lower case 12 by insert molding. Nuts through which screws are inserted when fixing the busbars 30 to the lower case 12 afterwards are also fixed to the lower case 12 by insert molding. In this way, some of the multiple busbars 30 and nuts are integrated into the lower case 12 by insert molding.

[0030] Case 10 is a resin molded product made of resin material. Case 10 is also made of an insulating material. In this embodiment, case 10 is made of an insulating resin material. Therefore, case 10 is an insulating resin housing. In other words, the upper case 11 and lower case 12 that make up case 10 are both resin molded products made of insulating resin.

[0031] As the resin material constituting the case 10, considering the heat resistance temperature and strength, for example, polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), or an alloy of polyphenylene ether (PPE) and nylon can be used. The upper case 11 and the lower case 12 may be made of the same resin material or may be made of different resin materials.

[0032] The relay 20 housed in case 10 is an electronic component that has the function of turning power on and off. Specifically, in Figure 1, the relay 20 has the function of switching between interrupting and supplying DC power supplied from battery 2 to battery interruption unit 1 to inverter 3. Furthermore, the relay 20 is a mechanical relay (contact relay). In this embodiment, other types of relays (for example, semiconductor relays and contactless relays) can also be used for relay 20, but in order to reliably switch between interrupting and supplying large currents from large-capacity batteries installed in electric vehicles such as hybrid electric vehicles or pure electric vehicles, it is more preferable for relay 20 to be a mechanical relay.

[0033] As shown in Figures 2 to 5, the relay 20 has a pair of terminals 21 and an insulating relay housing 22 to which the pair of terminals 21 are fixed. The pair of terminals 21 are fixed terminals. The pair of terminals 21 are also external connection terminals that are connected to an external member. Specifically, each of the pair of terminals 21 is connected to the busbar 30. The pair of terminals 21 are metal terminals made of a metallic material. The pair of terminals 21 are electrically isolated.

[0034] Although not shown in the diagram, the relay 20 has a movable contact that moves in and out of contact with one of a pair of fixed terminals 21. The relay 20 can interrupt or supply current by having this movable contact move in and out of contact with the fixed terminal.

[0035] The relay housing 22 is a resin housing made of, for example, an insulating resin material. As an example, the relay housing 22 is a rectangular parallelepiped having six faces (top, bottom, and four sides). The movable contact is housed inside this relay housing 22.

[0036] As shown in Figures 2 and 3, the relay 20 further has an insulating plate 22a located between a pair of terminals 21. The insulating plate 22a is an insulating wall that separates the pair of terminals 21. Specifically, the insulating plate 22a is part of the relay housing 22 and is installed in an upright position on the surface of the relay housing 22 where the terminals 21 are provided.

[0037] In this embodiment, the side surface of the relay housing 22 is not provided with mounting parts (collars) for fixing the relay housing 22 to the case 10 with screws. In other words, the side surface of the relay housing 22 is not provided with mounting parts that protrude from the side surface of the relay housing 22 and have screw holes (such as the mounting parts that protrude from the side surface of the relay housing 22X as shown in Figure 7, which will be described later).

[0038] As shown in Figures 2 and 4, the relay 20 is located in the case 10. In this embodiment, the relay 20 is located in the lower case 12. Specifically, the relay housing 22 of the relay 20 is housed in a relay housing section 12a provided in the lower case 12. In this case, the relay housing 22 is housed in the relay housing section 12a of the lower case 12 in a sideways position, and the terminals 21 of the relay 20 are located on the side of the relay housing 22. That is, as shown in Figure 4, the relay 20 is arranged so that the terminals 21 are sideways, and the terminals 21 face sideways rather than upward (towards the upper case 11). As a result, the insulating plate 22a located between the pair of terminals 21 is also located on the side of the relay housing 22.

[0039] Furthermore, the relay 20 is fixed to the case 10. In this embodiment, the relay 20 is fixed to the lower case 12. In this case, the relay 20 is not directly fixed to the lower case 12, but is fixed to the lower case 12 by a busbar 30 that is fixed to the lower case 12 in advance. Specifically, as shown in Figures 2 and 4, the relay 20 is fixed to the busbar 30 (relay busbar 30a) fixed to the lower case 12 by screwing the terminals 21 of the relay 20 together with screws 50. The relay busbar 30a and the terminals 21 of the relay 20 are in surface contact.

[0040] At least one relay 20 is provided in the battery disconnection unit 1. In this embodiment, the battery disconnection unit 1 includes a plurality of relays 20. Among the plurality of relays 20, there is a first main relay on the P side corresponding to the P side electrode of the battery 2 (see Figure 1) and a second main relay on the N side corresponding to the N side electrode of the battery 2 (see Figure 1). Specifically, as shown in Figures 2 and 3, the case 10 is provided with two relays 20, the first main relay on the P side and the second main relay on the N side. A pre-charge relay may also be included among the plurality of relays 20. Furthermore, if the battery disconnection unit 1 has a rapid charging circuit, the plurality of relays 20 may include a first rapid charging relay on the P side corresponding to the P side electrode of the battery 2 and a second rapid charging relay on the N side corresponding to the N side electrode of the battery 2.

[0041] The busbar 30, positioned in case 10, is a wiring component through which electric current flows and constitutes an electrical path. As the busbar 30 is a wiring component through which electric current flows, it is made of a conductive material. The busbar 30 also functions as a heat dissipation component (heat sink) to dissipate heat generated by heat-generating components. For example, the busbar 30 dissipates heat generated by the relay 20, which is one of the heat-generating components. Therefore, the busbar 30 is preferably made of a metallic material such as copper (Cu) or aluminum (Al), taking into consideration its electrical and thermal conductivity.

[0042] Also, in this embodiment, since a large current flows through the bus bar 30, the thickness of the bus bar 30 is relatively thick. Therefore, the bus bar 30 is a metal rigid body having a thick thickness and high strength. For example, when the battery cut-off unit 1 is used in a pure electric vehicle, the thickness of the bus bar 30 is preferably more than 2 mm, and further preferably 3 mm or more. For this reason, the bus bar 30 has a thickness that does not bend even when tightened with a screw when screwing the bus bar 30.

[0043] In this embodiment, the bus bar 30 is made of copper as an example of a metal material. Specifically, the bus bar 30 is composed of a plate-shaped metal plate having a constant thickness made of pure copper or a copper alloy. The bus bar 30 is formed into a three-dimensional predetermined shape by bending a flat metal plate punched into a predetermined shape by pressing or the like. However, the bus bar 30 is not limited to being composed of a plate-shaped metal plate. For example, it may be composed of a cast metal conductor (including the case where the metal is an alloy) formed by a casting method (including die casting). In particular, when the bus bar 30 is composed of a cast metal conductor, the metal material constituting the bus bar 30 is not limited to copper, and may be other metal materials such as aluminum.

[0044] Also, in order to achieve both high performance and low cost of the battery cut-off unit 1, a part of the plurality of bus bars 30 provided in the battery cut-off unit 1 may be composed of the above-mentioned metal plate, and the other part (for example, all the rest) of the bus bar 30 may be composed of the above-mentioned cast metal conductor.

[0045] A plating film is preferably formed on the surface of the bus bar 30. Thereby, the contact resistance can be reduced. The plating film can be formed by performing a plating process on the bus bar 30 as a surface treatment. The plating film is, for example, a Ni - Sn plating film made of nickel and tin, but is not limited thereto.

[0046] The bus bar 30 is arranged at least one in the battery cut-off unit 1. As shown in FIGS. 2 and 3, in the present embodiment, a plurality of bus bars 30 are arranged in the case 10. As shown in FIGS. 2 to 4, among the plurality of bus bars 30, a relay bus bar 30a which is a bus bar 30 connected to the relay 20 is included. In this case, the relay bus bar 30a is connected to the terminal 21 of the relay 20. Specifically, as shown in FIGS. 2 and 4, the relay bus bar 30a is fastened to the terminal 21 of the relay 20 by a screw 50. As shown in FIGS. 2 and 3, since two terminals 21 are provided in one relay 20, one relay 20 is fixed to two relay bus bars 30a. The two relay bus bars 30a are arranged side by side.

[0047] Among the plurality of bus bars 30, there are included a bus bar 30 connected to an electronic component other than the relay 20, and a connecting bus bar 30 that is not connected to an electronic component and is only connected to other bus bars 30.

[0048] Each of the two relay bus bars 30a connected to the relay 20 has, as shown in FIG. 4, a first plate portion 31 and a second plate portion 32 erected on the first plate portion 31. The first plate portion 31 and the second plate portion 32 are formed by bending into an L shape. That is, each relay bus bar 30a has a portion formed in an L shape. Note that the shape of the relay bus bar 30a is not limited to this.

[0049] The plurality of bus bars 30 are fixed to the case 10. Specifically, the plurality of bus bars 30 are fixed to the lower case 12 of the case 10. In this case, among the plurality of bus bars 30, there are included a bus bar 30 directly fixed to the case 10 by insert molding, and a bus bar 30 fixed by screwing a screw into a nut fixed to the case 10 by insert molding. That is, a nut through which a screw for fixing the bus bar 30 is inserted when the bus bar 30 is retrofitted to the lower case 12 is fixed to the lower case 12 by insert molding.

[0050] In this embodiment, at least the relay busbar 30a connected to the relay 20 is fixed to the case 10 by insert molding. Specifically, the relay busbar 30a is fixed to the lower case 12 of the case 10 by insert molding. Therefore, a part of the relay busbar 30a is embedded in a part of the lower case 12. Specifically, as shown in Figures 4 and 5, a part or all of the first plate portion 31 of the busbar 30, which is the relay busbar 30a, is embedded in the lower case 12. In this embodiment, the entire first plate portion 31 is embedded in the lower case 12. This allows the relay busbar 30a to be firmly fixed to the lower case 12. In this embodiment, the first plate portion 31 of the relay busbar 30a is located below the relay housing portion 12a in the lower case 12.

[0051] Furthermore, as shown in Figures 4 and 5, the second plate portion 32 of the busbar 30, which is the relay busbar 30a, is erected relative to the lower case 12. In other words, the second plate portion 32 is exposed from the lower case 12 and extends upward (towards the upper case 11) from the lower case 12. The end of the second plate portion 32 faces the terminal 21 of the relay 20. In other words, the second plate portion 32 extends at least to the position of the terminal 21 of the relay 20.

[0052] As shown in Figures 2 and 4, the terminals 21 of the relay 20 and the busbar 30 are fixed together by screws 50. In this embodiment, the terminals 21 of the relay 20 and the second plate portion 32 of the busbar 30a, which is the relay busbar 30a, are fixed together by screws 50. Specifically, as shown in Figures 3 and 5, a through hole 32a is provided as a screw hole at the end of the second plate portion 32, and the relay busbar 30a and the relay 20 can be fixed together by inserting the screw 50 through the through hole 32a of the second plate portion 32 and screwing it into the terminals 21 of the relay 20. The through hole 32a provided in the second plate portion 32 which is erected on the first plate portion 31 opens to the side. Therefore, the insertion direction of the screw 50 is parallel to the bottom surface of the lower case 12. The screw 50 is an example of a fastening member, and in this embodiment, it is a bolt. However, the screw 50 is not limited to a bolt.

[0053] As shown in Figures 2 to 5, the relay cover 40 is a cover that covers the relay 20. Specifically, as shown in Figures 2 and 4, the relay cover 40 is positioned to cover the relay 20 located in the relay housing 12a of the lower case 12. In this embodiment, the relay cover 40 covers the relay 20 such that the entire relay housing 22 of the relay 20 is hidden when viewed from above, and the side surface of the relay housing 22 of the relay 20 is exposed when viewed from the side. Therefore, in the direction in which the screw 50 is inserted, the terminals 21 of the relay 20 are not covered by the relay cover 40.

[0054] Furthermore, the relay cover 40 holds the relay 20 in place against the case 10. Specifically, the relay cover 40 holds the relay housing 22 of the relay 20, which is located in the lower case 12, against the lower case 12. As shown in Figure 2, in this embodiment, since two relays 20 are located in the lower case 12, two relay covers 40 are located in the lower case 12.

[0055] As shown in Figure 2, the relay cover 40 is positioned on the top of a support portion 12b provided on the lower case 12, and the relay cover 40 is supported by the support portion 12b. In this embodiment, three support portions 12b are provided for one relay 20, so the relay cover 40 is supported by three support portions 12b in a three-point support manner.

[0056] The relay cover 40, positioned on the support portion 12b, is fixed to the support portion 12b at the mounting portion 40a. The relay cover 40 is provided with a mounting portion 40a as a part to be attached to the support portion 12b. The mounting portion 40a is provided on the relay cover 40 at a position corresponding to the support portion 12b. As shown in Figures 2 and 3, in this embodiment, since the lower case 12 is provided with three support portions 12b, one relay cover 40 is provided with three mounting portions 40a. Furthermore, the three mounting portions 40a are provided on the outer circumference of the relay cover 40.

[0057] Furthermore, multiple protrusions are formed on the upper surface of the relay cover 40. By providing these protrusions on the relay cover 40, lead wires, harnesses, and other wiring (not shown) routed inside the case 10 can be hooked onto or pinched with the protrusions and secured, making it easy to house the wiring inside the case 10.

[0058] The relay cover 40 is a resin molded product made of an insulating resin material. The resin material for the relay cover 40 can be, for example, PPS, PBT, or an alloy of PPE and nylon, taking into consideration heat resistance and strength, similar to the case 10. The relay cover 40 and the case 10 may be made of the same resin material or different resin materials.

[0059] The relay cover 40 and the case 10 are joined together. Specifically, the mounting portion 40a of the relay cover 40 and the support portion 12b of the lower case 12 are joined together. In this embodiment, the mounting portion 40a of the relay cover 40 and the support portion 12b of the lower case 12 are joined together by ultrasonic welding, heat welding, or laser welding. In this case, the resin constituting the relay cover 40 and the resin constituting the lower case 12 melt together, thereby joining the mounting portion 40a of the relay cover 40 and the support portion 12b of the lower case 12.

[0060] Furthermore, when the relay cover 40 and the lower case 12 are joined by ultrasonic welding, it is preferable that the relay cover 40 and the lower case 12 be made of the same resin material. In this case, it is preferable that the relay cover 40 and the lower case 12 be made of a resin material such as an alloy of PPE and nylon. Also, when the relay cover 40 and the lower case 12 are joined by heat welding, the relay cover 40 and the lower case 12 may be made of different resin materials, or they may be made of the same resin material.

[0061] The water cooler 60 is an example of a heat dissipation component (heat sink). Therefore, the water cooler 60 dissipates heat generated in the battery shut-off unit 1 by conducting it to the water cooler 60.

[0062] The water cooler 60 is a cooler that cools the heat generated by the battery shut-off unit 1. In this embodiment, the water cooler 60 cools the heat generated by the battery shut-off unit 1 with cooling water. For example, the water cooler 60 cools the heat generated by the relay 20 and the heat generated by the busbar 30. As shown in Figures 4 and 5, the relay 20 is located above the water cooler 60. The busbar 30, which is connected to the terminal 21 of the relay 20, is located above the water cooler 60. The water cooler 60 may also cool the heat generated by the fuse or resistor, etc.

[0063] As shown in Figures 4 and 5, the water cooler 60 has a flow path 61 through which cooling water flows. In this embodiment, the water cooler 60 has two flat plate sections arranged with a gap between them. The gap between these two flat plate sections becomes the flow path 61. Specifically, as shown in Figure 3, the water cooler 60 is a thin metal housing with a rectangular shape in plan view, and is made of metal plates. As the metal material that makes up the water cooler 60, for example, aluminum, copper, or stainless steel can be used. The water cooler 60 may be made of resin instead of metal, but it is preferable that it be made of metal. By making the water cooler 60 out of metal, the heat generated in the battery shut-off unit 1 can be efficiently conducted to the water cooler 60.

[0064] The cooling water in the water cooler 60 flows in one direction through the flow path 61. As shown in Figure 3, in this embodiment, the water cooler 60 has a first opening 61a at one end in the longitudinal direction of the water cooler 60 and a second opening 61b at the other end in the longitudinal direction of the water cooler 60. One of the first opening 61a and the second opening 61b is a supply port (upstream opening) through which the cooling water is supplied, and the other of the first opening 61a and the second opening 61b is a discharge port (downstream opening) through which the cooling water is discharged.

[0065] Alternatively, the first opening 61a and the second opening 61b may be connected by an external flow path (pipe) to circulate the cooling water flowing through the flow path 61. In this case, it is preferable that a heat exchanger be provided in the external flow path connecting the first opening 61a and the second opening 61b.

[0066] As shown in Figures 4 and 5, the water cooler 60 is located below the case 10. In other words, the case 10 is located above the water cooler 60. Therefore, the case 10 is located opposite the water cooler 60. Specifically, the water cooler 60 is located below the lower case 12 of the case 10. In other words, the water cooler 60 is facing the lower case 12 of the case 10.

[0067] The water cooler 60 is positioned to cover the entire bottom surface of the lower case 12. As shown in Figures 2 and 3, in this embodiment, the external shape of the water cooler 60 is the same as the external shape of the case 10. In other words, the external shape of the water cooler 60 is the same as the external shapes of the upper case 11 and the lower case 12, respectively.

[0068] The water cooler 60 is fixed to the lower case 12 by screws. As shown in Figure 3, in this embodiment, screw holes are provided at each of the four corners of the water cooler 60 and the lower case 12. The water cooler 60 and the lower case 12 are fixed together by screwing screws into these screw holes.

[0069] The water cooler 60, together with the case 10, constitutes the outer casing of the battery cutoff unit 1. Specifically, the water cooler 60 constitutes the bottom of the battery cutoff unit 1, and the lower surface of the water cooler 60 (the surface opposite to the heat conduction layer 70) is an exposed surface. As a result, the heat conducted to the busbar 30 and the heat generated by the busbar 30 are conducted to the water cooler 60, allowing the heat conducted to the busbar 30 and the heat generated by the busbar 30 to be efficiently dissipated to the outside.

[0070] In particular, in this embodiment, as described above, a plurality of busbars 30 are embedded and fixed in the lower case 12 by insert molding. Therefore, the water cooler 60 and the plurality of busbars 30 embedded in the lower case 12 are in close proximity. This allows heat conducted to the busbars 30 embedded in the lower case 12 and heat generated by the busbars 30 to be efficiently conducted to the water cooler 60. For example, the heat from the relay 20 that has been conducted to the busbar 30 connected to the relay 20 (relay busbar 30a) can be efficiently conducted to the water cooler 60. Therefore, the heat from the relay 20 can be efficiently dissipated.

[0071] As shown in Figures 4 and 5, the water cooler 60 faces the case 10 via a heat conduction layer 70. In other words, the heat conduction layer 70 is located on the water cooler 60 side of the case 10, and the heat conduction layer 70 is located between the case 10 and the water cooler 60. Specifically, the heat conduction layer 70 is interposed between the lower case 12 of the case 10 and the water cooler 60. The heat conduction layer 70 is sandwiched between the lower case 12 and the water cooler 60.

[0072] The thermal conductive layer 70 is connected to the water cooler 60. In this embodiment, the thermal conductive layer 70 is in contact with the water cooler 60. The thermal conductive layer 70 is also in contact with the case 10. In other words, the thermal conductive layer 70 is in contact with both the case 10 and the water cooler 60. Specifically, the thermal conductive layer 70 is sandwiched between the lower case 12 and the water cooler 60, and is in close contact with the lower surface (resin surface) of the lower case 12 and the upper surface of the water cooler 60.

[0073] The thermal conductive layer 70 conducts the heat generated in the battery shut-off unit 1 to the water cooler 60. Specifically, the thermal conductive layer 70 conducts the heat conducted to the busbar 30 fixed to the case 10 and the heat generated in the busbar 30 to the water cooler 60. Therefore, the thermal conductive layer 70 is preferably made of a material with high thermal conductivity. As an example, the thermal conductivity of the thermal conductive layer 70 is 1 W / m·K or higher, but is not limited to this.

[0074] The heat conduction layer 70 is preferably positioned opposite the busbar 30 in order to conduct heat from the busbar 30 to the water cooler 60. Specifically, the heat conduction layer 70 faces the relay busbar 30a. This allows heat from the relay busbar 30a to be efficiently conducted to the water cooler 60 via the heat conduction layer 70.

[0075] As shown in Figure 3, the battery cutoff unit 1 has multiple heat conduction layers 70. That is, the heat conduction layer 70 is divided into multiple parts. The multiple heat conduction layers 70 are arranged to match the uneven shape of the lower surface of the lower case 12. Specifically, the multiple heat conduction layers 70 are arranged to fit into the recesses of the lower case 12. That is, the outer shape of each of the multiple heat conduction layers 70 is shaped to fit into the recesses of the lower case 12. Note that each of two of the multiple heat conduction layers 70 faces each of the two relay busbars 30a.

[0076] Each of the multiple heat conductive layers 70 is a sheet-like heat conductive sheet (thermal sheet). Each heat conductive layer 70 is a flat sheet member with a uniform thickness. However, the thickness of each heat conductive layer 70 does not have to be uniform. Also, the heat conductive layer 70 may be a single sheet member.

[0077] The thermal conductive layer 70 is preferably made of an insulating material to ensure insulation between the water cooler 60 and the busbar 30. In other words, the thermal conductive layer 70 is preferably a thin, sheet-like insulating sheet made of an insulating material. Alternatively, the thermal conductive layer 70 may be a resin sheet made of a resin material. In this embodiment, the thermal conductive layer 70 is made of an insulating resin material. As an example, a silicone-based or acrylic-based resin material can be used as the resin material constituting the thermal conductive layer 70. The thermal conductive layer 70, which is a thermal conductive sheet, may be made of two laminated resin sheets.

[0078] The thermal conductive layer 70 may be made of, for example, an elastomer with high thermal conductivity and rubber elasticity. As a result, the thermal conductive layer 70 elastically deforms when sandwiched between the lower case 12 and the water cooler 60, allowing the thermal conductive layer 70 to be in close contact with the lower case 12 and the water cooler 60. This allows the heat generated in the battery shut-off unit 1 to be efficiently conducted to the water cooler 60 via the thermal conductive layer 70.

[0079] From the standpoint of conducting heat from the busbar 30 to the water cooler 60 via the heat conduction layer 70, it is preferable for the thickness of the heat conduction layer 70 to be thin. For example, the thickness of the heat conduction layer 70 should be 2 mm or less. In this embodiment, the thickness of the heat conduction layer 70 is 1 mm.

[0080] Furthermore, as shown in Figure 5, the lower case 12 of case 10 has a bottom plate portion 12c. The bottom plate portion 12c has a first portion that overlaps with the heat conduction layer 70 and a second portion that does not overlap with the heat conduction layer 70. The thickness of the first portion of the bottom plate portion 12c that overlaps with the heat conduction layer 70 is thinner than the thickness of the second portion of the bottom plate portion 12c that does not overlap with the heat conduction layer 70. For example, the thickness of the first portion of the bottom plate portion 12c that overlaps with the heat conduction layer 70 is 0.7 mm, and the thickness of the second portion of the bottom plate portion 12c that does not overlap with the heat conduction layer 70 is 1.5 mm.

[0081] In this way, by making the thickness of the first portion of the bottom plate portion 12c that overlaps with the heat conductive layer 70 thinner than the thickness of the second portion of the bottom plate portion 12c that does not overlap with the heat conductive layer 70, it is possible to improve the heat dissipation of the battery cutoff unit 1 while ensuring insulation between the case 10 and the heat conductive layer 70.

[0082] As described above, the battery shutoff unit 1 according to this embodiment comprises an insulating resin case 10, a relay 20 arranged in the case 10, a busbar 30 connected to the terminals 21 of the relay 20 and fixed to the case 10 by insert molding, a water cooler 60, and a heat conductive layer 70 arranged on the water cooler 60 side (heat dissipation member side) of the case 10.

[0083] As described above, in the battery cutoff unit 1 according to this embodiment, the busbar 30 is fixed to the insulating case 10 by insert molding, so the insulation of the battery cutoff unit 1 from the busbar 30 through which a large current flows can be easily ensured. Moreover, since the relay 20 is connected to the busbar 30 fixed by insert molding, the mechanical strength of the connection between the relay 20 and the busbar 30 can be ensured. Furthermore, since the heat conduction layer 70 is arranged on the water cooler 60 side of the case 10 to which the busbar 30 (relay busbar 30a) is fixed by insert molding, the heat conducted to the busbar 30 (relay busbar 30a) and the heat generated by the busbar 30 can be efficiently conducted to the water cooler 60 via the heat conduction layer 70. For example, as shown by the arrow in Figure 5, the heat of the relay 20 conducted to the relay busbar 30a connected to the relay 20 is conducted from the second plate portion 32 to the first plate portion 31 of the relay busbar 30a, and further conducted to the water cooler 60 via the heat conduction layer 70. In this way, the heat from the busbar 30 (relay busbar 30a) can be efficiently dissipated.

[0084] Therefore, the battery disconnection unit 1 according to this embodiment makes it possible to achieve both strong connection between the relay 20 and the busbar 30, good heat dissipation, and good insulation.

[0085] Furthermore, in the battery cutoff unit 1 according to this embodiment, the heat conductive layer 70 is a heat conductive sheet.

[0086] This configuration allows the thermal conductive layer 70 to be easily attached to the case 10.

[0087] Furthermore, the battery shut-off unit 1 according to this embodiment includes a water cooler 60, and the heat conduction layer 70 is positioned between the case 10 and the water cooler 60.

[0088] This configuration allows the battery shut-off unit 1 to be a product that includes a case 10 and a water cooler 60. In other words, a water cooler-equipped battery shut-off unit 1 can be realized.

[0089] Furthermore, in the battery shut-off unit 1 according to this embodiment, the heat conductive layer 70 is in contact with the case 10 and the water cooler 60, respectively.

[0090] This configuration allows the heat conducted to the busbar 30 (relay busbar 30a) and the heat generated in the busbar 30 to be more efficiently transferred to the water cooler 60 via the heat conduction layer 70. This further improves the heat dissipation performance of the battery cutoff unit 1.

[0091] Furthermore, in the battery shut-off unit 1 according to this embodiment, the water cooler 60 constitutes the bottom of the battery shut-off unit 1, and the side of the water cooler 60 opposite to the heat conduction layer 70 is exposed.

[0092] This configuration allows the heat from the busbar 30 (relay busbar 30a) conducted to the water cooler 60 to be efficiently dissipated into the atmosphere. This further improves the heat dissipation performance of the battery shut-off unit 1.

[0093] Furthermore, in the battery cutoff unit 1 according to this embodiment, the heat conductive layer 70 is made of an insulating resin material.

[0094] In this configuration, not only the insulating case 10 but also the insulating thermal conductive layer 70 is interposed between the busbar 30 (relay busbar 30a) and the water cooler 60 as an insulating material. This further enhances the insulating properties of the battery cutoff unit 1 compared to the case where the thermal conductive layer 70 is made of a conductive material.

[0095] It is also possible to construct a structure in which the heat conductive layer 70 and the water cooler 60 are insert-molded inside the case 10 (lower case 12), but this structure would result in the following problems.

[0096] The first problem is that, during insert molding, the heat conductive layer 70 can only be placed around the bus bar 30 (relay bus bar 30a), which limits the shape of the heat conductive layer 70 and reduces the heat dissipation performance of the battery cutoff unit 1.

[0097] The second problem is that when a heat conductive layer 70 is attached to the water cooler 60 and then insert molded, the heat conductive layer 70 deteriorates because its heat resistance temperature (around 130 degrees Celsius) is lower than the temperature of the case 10 (lower case 12) during insert molding (resin temperature is around 300 degrees Celsius).

[0098] In contrast, in the battery shut-off unit 1 according to this embodiment, the heat conductive layer 70 is attached externally to the case 10 (lower case 12), so the shape of the heat conductive layer 70 and the water cooler 60 can be freely set. Furthermore, in the battery shut-off unit 1 according to this embodiment, the heat conductive layer 70 and the water cooler 60 are not insert-molded inside the case 10 (lower case 12), but are directly attached (externally) to the bottom of the case 10. Thus, the battery shut-off unit 1 according to this embodiment does not cause the first and second problems described above, and furthermore, by providing insulation in both the heat conductive layer 70 and the case 10, it is possible to miniaturize the battery shut-off unit 1.

[0099] Furthermore, in the battery cutoff unit 1 according to this embodiment, the bottom plate portion 12c of the case 10 has a first portion which overlaps with the heat conductive layer 70 and a second portion which does not overlap with the heat conductive layer 70, and the thickness of the first portion is thinner than the thickness of the second portion.

[0100] The resin material that makes up the case 10 has a lower thermal conductivity compared to metal materials. Therefore, by making the thickness of the first portion of the bottom plate portion 12c of the case 10 that overlaps with the thermal conductive layer 70 thinner, the heat from the busbar 30 (relay busbar 30a) can be efficiently conducted to the thermal conductive layer 70. Furthermore, by making the thickness of the second portion of the bottom plate portion 12c of the case 10 that does not overlap with the thermal conductive layer 70 thicker, the mechanical strength of the case 10 to which the busbar 30 is fixed can be ensured. This makes it possible to further achieve a balance between the robustness of the connection between the relay 20 and the busbar 30, heat dissipation, and insulation.

[0101] Next, the manufacturing method of the battery shut-off unit 1 according to this embodiment will be described with reference to Figure 6. Figure 6 is a diagram illustrating the manufacturing method of the battery shut-off unit 1 according to this embodiment. In Figures 6(a) to (d), the left figure is a side view, and the right figure is a perspective view. Note that Figure 6 shows only some of the components that make up the battery shut-off unit 1. For example, only one of the two relays 20 is shown, and only the relay busbar 30a is shown.

[0102] As shown in Figure 6(a), first, the relay 20 is placed in the case 10 to which the busbar 30 is fixed. Specifically, the relay 20 is placed in the lower case 12 to which multiple busbars 30, including the relay busbar 30a, are fixed by insert molding. At this time, the relay housing 22 of the relay 20 is placed in the relay housing section 12a of the lower case 12 so that the terminals 21 of the relay 20 and the insertion holes 32a of the relay busbar 30a are aligned.

[0103] Next, as shown in Figure 6(b), the relay cover 40 is placed on top of the relay 20 located in the case 10. Specifically, the relay cover 40 is placed on the support portion 12b of the lower case 12 so as to cover the relay housing 22 of the relay 20 located in the lower case 12. At this time, the relay cover 40 is placed on the support portion 12b such that the mounting portion 40a of the relay cover 40 is located on the support portion 12b of the lower case 12. Also, when the relay cover 40 is placed on the support portion 12b, the relay cover 40 and the relay housing 22 of the relay 20 may or may not be in contact.

[0104] Next, as shown in Figure 6(c), the relay cover 40 is pressed against the case 10 and the relay cover 40 is fixed to the case 10. Specifically, the mounting portion 40a of the relay cover 40 and the support portion 12b of the lower case 12 are joined together while applying pressure to the relay cover 40 from top to bottom.

[0105] For example, a pressing member (not shown) is placed on the relay cover 40, and the pressing member is pressed against the relay cover 40 using a pressurizer, thereby pressurizing the relay cover 40 and joining the mounting portion 40a of the relay cover 40 to the support portion 12b of the lower case 12. The mounting portion 40a of the relay cover 40 and the support portion 12b of the lower case 12 are joined by, for example, ultrasonic waves, heat welding, or laser welding. In other words, by applying ultrasonic vibrations, heating, or laser light to the mounting portion 40a of the relay cover 40, the resin constituting the relay cover 40 and the resin constituting the lower case 12 are melted, thereby joining the mounting portion 40a of the relay cover 40 to the support portion 12b of the lower case 12.

[0106] At this time, when the relay cover 40 is placed on the support portion 12b (step (b) in Figure 6), even if the relay cover 40 and the relay housing 22 of the relay 20 are not in contact, by joining the relay cover 40 and the support portion 12b of the lower case 12 while applying pressure to the relay cover 40, the relay cover 40 will come into contact with the relay housing 22 and press the relay housing 22 against the lower case 12.

[0107] In this way, by joining the relay cover 40 to the lower case 12 while applying pressure to the relay cover 40, the relay 20 can be held in the lower case 12 while being pressed down by the relay cover 40. Furthermore, even if the relay 20 is tilted when placed in the lower case 12 in step 6(a) of Figure 6, by joining the relay cover 40 to the lower case 12 while applying pressure to the relay cover 40, the relay cover 40 is joined to the lower case 12 flexibly, so the relay 20 can be held in the lower case 12 by the relay cover 40 without generating stress on the relay 20. In this way, the relay 20 can be stably fixed to the lower case 12 without directly fixing the relay 20 to the lower case 12.

[0108] Next, as shown in Figure 6(d), after fixing the relay cover 40 and the case 10, the terminals 21 of the relay 20 and the busbar 30 are fixed with screws 50. Specifically, the screws 50 are inserted through the insertion holes 32a of the relay busbar 30a and screwed into the terminals 21 of the relay 20. This allows the relay busbar 30a and the relay 20 to be fixed electrically and mechanically. At this time, in the direction of insertion of the screws 50, the terminals 21 of the relay 20 are not covered by the relay cover 40. This makes it easy to fix the relay 20 and the relay busbar 30a with screws 50 even after the relay 20 is covered with the relay cover 40.

[0109] Here, the features of the manufacturing method of the battery shut-off unit 1 according to this embodiment will be explained in comparison with the comparative example battery shut-off unit 1X using Figure 7. Figure 7 is a diagram showing the configuration of the comparative example battery shut-off unit 1X.

[0110] As shown in Figure 7, the battery cutoff unit 1X comprises a resin case 10X and a relay 20X and a busbar 30X housed in the case 10X.

[0111] In the battery cutoff unit 1X shown in Figure 7, the relay 20X is fixed to the case 10X. In this case, a bolt is inserted as a screw 51X through the insertion hole of the fixing mounting part (collar) provided on the side of the relay housing 22X of the relay 20X, and the screw 51X is screwed into a nut 35X embedded in the case 10X. This allows the relay housing 22X of the relay 20X to be fixed to the case 10X. After fixing the relay 20X to the case 10X, the relay busbar 30X is screwed to the terminal 21X of the relay 20X with a screw 52X and to the case 10X with a screw 53X, thereby electrically and mechanically connecting the relay 20X and the relay busbar 30a, and fixing the relay busbar 30a to the case 10X. In Figure 7, when fixing the relay busbar 30a, which is busbar 30X, to the case 10X with screws 53X, the upper busbar 30b, which is the upper busbar 30X, is placed on top of the relay busbar 30a, and the upper busbar 30b and the relay busbar 30a are fastened together with screws 53X.

[0112] In the battery cutoff unit 1X shown in Figure 7, since the case 10X is made of resin, as shown in Figure 7, the case 10X may be unintentionally warped or deformed. If the relay 20X is placed in a part of the case 10X that has been deformed in this way, the relay 20X will be fixed to the case 10X in a tilted position. Also, even if the case 10X is not deformed, the relay 20X may be tilted during assembly and fixed to the case 10X in a tilted position. Thus, in the conventional battery cutoff unit 1X, assembly defects of the relay 20X can occur.

[0113] Furthermore, if the relay 20X is improperly assembled, the busbar 30X (relay busbar 30a) connected to the relay 20X may be screwed to the terminal 21X of the relay 20X or fixed to the case 10X while tilted. In addition, as a result of the relay busbar 30a being tilted, the upper busbar 30b, which is fastened together with the relay busbar 30a, will also be connected while tilted relative to the relay busbar 30a. Thus, improper assembly of the busbar 30X (relay busbar 30a) can occur in the conventional battery cutoff unit 1X.

[0114] When a faulty assembly of the relay busbar 30a occurs in this manner, the relay busbar 30a and the terminals 21X of the relay 20X and / or the upper busbar 30b will no longer make surface contact. In other words, if a faulty assembly of the relay busbar 30a occurs and the relay busbar 30a is tilted, the relay busbar 30a and the terminals 21X of the relay 20X may become connected by line contact or point contact, or the relay busbar 30a and the upper busbar 30b may become connected by line contact or point contact. Therefore, although conductivity is maintained, the resistance value at the connection point between the relay busbar 30a and the terminal 21X of the relay 20X and / or the upper busbar 30b increases, which may cause this connection point to become a heat source. Additionally, a gap may form between the contact surface of the relay busbar 30a and the contact surface of the terminal 21X of the relay 20X and / or the upper busbar 30b at the connection point between the relay busbar 30a and the upper busbar 30b, which may accelerate corrosion at this connection point.

[0115] In particular, if the thickness of the copper busbar 30X (relay busbar 30a) is 2 mm or less, the tightening force when fastening the relay busbar 30a with screws 51X and 52X may cause the relay busbar 30a to bend and be forcibly deformed, resulting in surface contact between the busbar 30X and the terminals 21X of the relay 20X and / or the upper busbar 30b. However, if the thickness of the copper busbar 30X (relay busbar 30a) exceeds 2 mm (for example, 3 mm or more), the busbar 30X will not deform under the tightening force of the screws, resulting in a faulty assembly of the relay busbar 30a, as shown in Figure 7. In pure electric vehicles, a larger current flows through the busbar 30X than in hybrid electric vehicles, so thicker busbars 30X with a thickness of 3 mm or more are used instead of thin busbars 30X with a thickness of 2 mm or less, making faulty assembly of the busbar 30X (relay busbar 30a) more likely.

[0116] Furthermore, if the relay busbar 30a is improperly assembled and connected to the terminal 21X of the relay 20X at an angle, not only will the above-mentioned heat generation and corrosion problems occur, but stress and strain will also occur in the relay busbar 30a and / or the terminal 21X of the relay 20X. When stress and strain occur in the relay busbar 30a and / or the terminal 21X of the relay 20X, the long-term reliability of the battery cutoff unit 1X will decrease.

[0117] As described above, in the structure of the battery cutoff unit 1X shown in Figure 7, when fixing the relay 20X and busbar 30X to the case 10X, the relay 20X and busbar 30X may be fixed at an angle, resulting in improper assembly of the relay 20X and busbar 30X.

[0118] In contrast, in the manufacturing method of the battery shut-off unit 1 according to this embodiment, instead of fixing the relay 20X to the case 10X and then fastening the relay 20X to the busbar 30X as in the battery shut-off unit 1X shown in Figure 7, the relay 20 is placed in the case 10 to which the busbar 30 has been fixed in advance, and the relay 20 is held in place by the relay cover 40 in the case 10, after which the busbar 30 and the relay 20 are fastened together with screws 50. Therefore, in the battery shut-off unit 1 according to this embodiment, unlike the battery shut-off unit 1X shown in Figure 7, assembly defects of the relay 20 and busbar 30 do not occur.

[0119] Furthermore, the battery cutoff unit 1 according to this embodiment is equipped with a relay cover 40 that covers the relay 20, and the relay cover 40 presses the relay 20 against the case 10. In addition, the terminals 21 of the relay 20 and the busbar 30 are fixed together with screws 50.

[0120] With this configuration, as described above, the relay 20 can be placed in the case 10 to which the busbar 30 is already fixed, and the relay 20 can be fixed to the case 10 with the relay cover 40, and then the busbar 30 (relay busbar 30a) and the terminals 21 of the relay 20 can be fixed with screws 50. This allows the relay 20 to be held in the case 10 without causing any looseness in the relay 20, and the relay 20 and the busbar 30 (relay busbar 30a) can be fixed with screws 50 without putting stress on the relay 20 and the busbar 30 (relay busbar 30a). Therefore, the relay 20 and the busbar 30 can be fixed to the case 10 without causing assembly defects of the relay 20 and the busbar 30. As a result, the busbar 30 (relay busbar 30a) and the terminals 21 of the relay 20 make surface contact, so it is possible to suppress increased resistance and heat generation at the connection part between the busbar 30 (relay busbar 30a) and the terminals 21 of the relay 20, and prevent gaps from forming and accelerating corrosion. Furthermore, since assembly defects of the relay 20 and busbar 30 do not occur, the relay 20 can be held in the case 10 without putting stress on the relay 20 and busbar 30. This also suppresses the generation of stress and strain on the busbar 30 (relay busbar 30a) and the terminal 21 of the relay 20. Therefore, a battery shut-off unit 1 with excellent long-term reliability can be realized.

[0121] Furthermore, in the battery cutoff unit 1 according to this embodiment, the terminals 21 of the relay 20 are not covered by the relay cover 40 in the direction in which the screw 50 is inserted. In other words, the terminals 21 of the relay 20 are exposed from the side of the relay cover 40.

[0122] This allows the relay 20 and the relay busbar 30a to be easily secured with screws 50 even after the relay 20 is covered with the relay cover 40.

[0123] Furthermore, as described above, the bus bar 30 (relay bus bar 30a) is fixed to the case 10 by insert molding. Specifically, the relay bus bar 30a is fixed to the lower case 12 by insert molding.

[0124] This configuration allows the busbar 30 (relay busbar 30a) and the case 10 to be pre-integrated and fixed together, thus eliminating assembly defects of the busbar 30. Furthermore, if the nuts through which the screws for fixing the busbar 30 to the case 10 are inserted are fixed to the case 10 by insert molding, these nuts and the relay busbar 30a can be fixed to the case 10 simultaneously by insert molding. In other words, the relay busbar 30a can be fixed to the case 10 without adding a separate insert molding process.

[0125] Furthermore, since no stress or distortion occurs in the bus bar 30 (relay bus bar 30a) fixed to the case 10 by insert molding, even when fastening the relay bus bar 30a fixed by insert molding to other bus bars 30 such as the upper bus bar with screws, the relay bus bar 30a and the other bus bars 30 can be made to make surface contact. In other words, the relay bus bar 30a and the other bus bars 30 can be connected without any gaps forming at the connection point between them.

[0126] Furthermore, in the battery cutoff unit 1 according to this embodiment, the relay busbar 30a, which is a busbar 30 connected to the relay 20, has a first plate portion 31 and a second plate portion 32 erected on the first plate portion 31. Part or all of the first plate portion 31 is embedded in the case 10, and the second plate portion 32 and the terminals 21 of the relay 20 are fixed together with screws 50.

[0127] With this configuration, the second plate portion 32 of the busbar 30 is erected from the first plate portion 31 so that it is exposed from the case 10, and the second plate portion 32 of the busbar 30 (relay busbar 30a) and the terminal 21 of the relay 20 can be easily fastened together with a screw 50.

[0128] Furthermore, in the battery shut-off unit 1 according to this embodiment, the relay 20 has a relay housing 22, and the terminals 21 are provided on the side surface of the relay housing 22. In other words, the relay 20 is arranged so that the terminals 21 are oriented horizontally.

[0129] This configuration allows the terminals 21 of the relay 20 to be easily positioned opposite the second plate portion 32 that rises from the first plate portion 31 of the busbar 30 embedded in the case 10, so that the busbar 30 and the terminals 21 of the relay 20 can be easily fastened together with screws 50.

[0130] Furthermore, in the battery cutoff unit 1 according to this embodiment, the thickness of the bus bar 30 (relay bus bar 30a) is 3 mm or more. In other words, the thickness of the bus bar 30 is such that it does not flex even when tightened with screws.

[0131] If the busbar 30 flexes due to the tightening force of the screws, the flexing of the busbar 30 allows the busbar 30 and the terminals 21 of the relay 20 to be fixed in surface contact when the busbar 30 and the terminals 21 of the relay 20 are fixed with screws. However, if the busbar 30 does not flex due to the tightening force of the screws, a faulty assembly of the relay 20 and the busbar 30 occurs, and the busbar 30 and the terminals 21 of the relay 20 cannot be fixed in surface contact. In contrast, in this embodiment, the relay 20 is placed in the case 10 to which the busbar 30 is fixed in advance, and the relay 20 is fixed to the case 10 with the relay cover 40, and then the busbar 30 (relay busbar 30a) and the relay 20 are fixed with screws 50. As a result, even when using a busbar 30 with a thickness of 3 mm or more (i.e., a busbar 30 that does not bend under the tightening force of screws) due to increased current, the relay 20 and the busbar 30 can be fixed to the case 10 without causing assembly defects of the relay 20 and the busbar 30. Therefore, the battery cutoff unit 1 according to this embodiment is suitable for pure electric vehicles, which have higher currents than hybrid electric vehicles.

[0132] (Modification) The technology of this disclosure has been described above based on embodiments, but this disclosure is not limited to the above embodiments.

[0133] For example, in the above embodiment, the busbar 30 insert-molded into the case 10 was not in contact with the heat conduction layer 70, but this is not limited to that. Specifically, as shown in Figure 5, in the above embodiment, a thin resin portion constituting the bottom plate portion 12c existed below the relay busbar 30a embedded in the bottom plate portion 12c of the lower case 12, but this is not limited to that. For example, as shown in Figure 8, a part of the busbar 30 may be exposed from the case 10 and in contact with the heat conduction layer 70. In Figure 8, the first plate portion 31 embedded in the bottom plate portion 12c of the relay busbar 30a is exposed from the lower case 12 (bottom plate portion 12c) and is in surface contact with the upper surface of the heat conduction layer 70.

[0134] Furthermore, as shown in Figure 9, a portion of the busbar 30 may be pre-covered with an insulating resin layer 80 before it is insert-molded into the case 10. In Figure 9, the first plate portion 31 of the relay busbar 30a is covered with the resin layer 80. As the resin layer 80, a heat-shrinkable tube made of an insulating resin material can be used. In this case, the busbar 30 can be covered with the resin layer 80 by inserting the busbar 30 into the heat-shrinkable tube and heat-treating it. The resin layer 80 may also be a resin coating. In this case, the busbar 30 can be covered with the resin layer 80 by applying an insulating resin liquid to the busbar 30 and curing it. By pre-covering a portion of the busbar 30 with the resin layer 80 in this way, the insulation between the busbar 30 and the metal water cooler 60 can be improved.

[0135] Furthermore, although the thermal conductive layer 70 in the above embodiment was a thermal conductive sheet, it is not limited to this. For example, the thermal conductive layer 70 may be a thermal conductive member formed by hardening a thermally conductive liquid. In this case, the thermal conductive layer 70 can be formed between the case 10 and the water cooler 60 by applying an insulating liquid between the case 10 and the water cooler 60 and hardening it. By forming the thermal conductive layer 70 by hardening a liquid in this way, even if minute irregularities exist on the surfaces of the case 10 and the water cooler 60, the thermal conductive layer 70 can be embedded in these minute irregularities. This allows the thermal conductive layer 70 to adhere tightly to the case 10 and the water cooler 60 without any gaps. Therefore, the heat generated in the battery cutoff unit 1 can be conducted to the water cooler 60 even more efficiently.

[0136] Furthermore, the heat conduction layer 70 may be a liquid heat conduction material. In other words, the heat conduction layer 70 between the case 10 and the water cooler 60 may remain in liquid form. In this case, silicone oil or grease can be used as the liquid heat conduction layer 70. By interposing the liquid heat conduction layer 70 between the case 10 and the water cooler 60 in this way, even if minute irregularities exist on the surfaces of the case 10 and the water cooler 60, the heat conduction layer 70 can be embedded in these minute irregularities. This allows the heat conduction layer 70 to adhere tightly to both the case 10 and the water cooler 60 without any gaps. Therefore, the heat generated by the battery shut-off unit 1 can be conducted to the water cooler 60 even more efficiently.

[0137] Furthermore, although the battery shutdown unit 1 in the above embodiment was equipped with a water cooler 60 which is a heat dissipation member, it is not limited to this. In other words, the battery shutdown unit 1 does not have to be equipped with a water cooler 60. For example, the battery shutdown unit 1 may consist only of a case 10 in which the relay 20 and busbar 30 are arranged and a heat conductive layer 70.

[0138] Furthermore, in the above embodiment, a water cooler 60 was used as a heat dissipation member to dissipate the heat generated in the battery cutoff unit 1, but the invention is not limited to this. The heat dissipation member to dissipate the heat generated in the battery cutoff unit 1 may be a metal block made of a metal material such as copper or aluminum, a Peltier element, a heat pipe, or a highly thermally conductive resin member having a high thermal conductivity (for example, a thermal conductivity of 1 W / m·K or more). Also, if the battery cutoff unit 1 does not have a heat dissipation member, the heat dissipation member to which the heat conduction layer 70 is connected may be a product such as a battery pack. In this case, the heat generated in the battery cutoff unit 1 will be conducted to the product such as a battery pack via the heat conduction layer 70. In other words, the product such as a battery pack functions as a heat dissipation member.

[0139] Furthermore, in the above embodiment, the terminals 21 of the relay 20 were provided on the side surface of the relay housing 22, but this is not limited to this, and they may be provided on the top surface of the relay housing 22. In other words, the relay 20 may be arranged so that the terminals 21 face upward, rather than being arranged so that the terminals 21 face sideways.

[0140] Furthermore, although the relay cover 40 and the case 10 were fixed by welding in the above embodiment, the invention is not limited to this. For example, the relay cover 40 and the case 10 may be fixed by screws or crimping.

[0141] Furthermore, in the above embodiment, the relay 20 is held in place in the case 10 by the relay cover 40, and then the terminals 21 of the relay 20 and the busbar 30 are fastened together with screws 50. However, the embodiment is not limited to this. For example, the relay 20, which is located in the case 10 on which the busbar 30 is fixed, and the busbar 30 may be fastened together with screws 50, and then the relay cover 40 may be joined to the case 10, thereby holding the relay 20 in place in the case 10 by the relay cover 40.

[0142] Furthermore, although the battery shut-off unit 1 was used in an electric vehicle in the above embodiment, it is not limited to that. For example, the battery shut-off unit 1 can also be applied to electrical products such as home appliances.

[0143] Furthermore, although the technology of this disclosure has been applied to the battery disconnection unit 1, it is not limited to this. The technology of this disclosure may be used in electrical connection boxes other than the battery disconnection unit 1. For example, the technology of this disclosure may be used in a charging unit connected to a battery. In addition, the technology of this disclosure may be used in electrical connection boxes other than those connected to a battery, as long as they have relays.

[0144] Furthermore, this disclosure also includes forms obtained by applying various modifications to the above embodiments that a person skilled in the art could conceive, and forms realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of this disclosure. In addition, this disclosure also includes any combination of two or more claims from the multiple claims described in the claims of this application, provided that they are not technically contradictory. For example, if the cited claims described in the claims of this application are made into a multi-claim or multi-multi-claim so as to refer to all of the higher-level claims without technically contradictory, then all combinations of claims included in that multi-claim or multi-multi-claim are also included in this disclosure.

[0145] The technology disclosed herein can be widely used in various products such as automobiles or electrical appliances.

[0146] 1 Battery cutoff unit 2 Battery 3 Inverter 10 Case 11 Upper case 12 Lower case 12a Relay housing 12b Support part 12c Bottom plate 20 Relay 21 Terminal 22 Relay housing 22a Insulating plate 30 Bus bar 30a Relay bus bar 31 First plate part 32 Second plate part 32a Through hole 40 Relay cover 40a Mounting part 50 Screw 60 Water cooler 61 Flow path 61a First opening 61b Second opening 70 Thermal conductive layer 80 Resin layer 100 Drive system

Claims

1. An electrical connection box comprising: a resin case having insulating properties and positioned opposite a heat dissipation member; a relay positioned in the case; a busbar connected to the terminals of the relay and fixed to the case by insert molding; and a heat conductive layer positioned on the heat dissipation member side of the case.

2. The electrical connection box according to claim 1, wherein the heat conductive layer is a heat conductive sheet.

3. The electrical connection box according to claim 1, comprising the heat dissipation member, wherein the heat conductive layer is disposed between the case and the heat dissipation member.

4. The electrical connection box according to claim 3, wherein the heat conductive layer is in contact with the case and the heat dissipation member, respectively.

5. The electrical connection box according to claim 4, wherein the heat conductive layer is a heat conductive member formed by hardening a heat conductive liquid.

6. The electrical connection box according to claim 4, wherein the heat conductive layer is a liquid heat conductive member.

7. The electrical connection box according to any one of claims 3 to 6, wherein the heat dissipation member is a water cooler, a metal block, a Peltier element, a heat pipe, a high thermal conductivity resin member, or a battery pack.

8. The electrical connection box according to any one of claims 3 to 6, wherein the heat dissipation member constitutes the bottom of the electrical connection box, and the side of the heat dissipation member opposite to the heat conduction layer side is exposed.

9. The electrical junction box according to any one of claims 1 to 6, wherein a portion of the busbar is exposed from the case and in contact with the heat conductive layer.

10. The electrical junction box according to any one of claims 1 to 6, wherein a portion of the busbar is pre-covered with an insulating resin layer.

11. An electrical junction box according to any one of claims 1 to 6, wherein a plating film is formed on the surface of the bus bar.

12. The electrical junction box according to any one of claims 1 to 6, wherein the busbar is made of a metal plate or a metal conductor formed by casting.

13. The electrical junction box according to any one of claims 1 to 6, wherein the electrical junction box comprises a plurality of busbars, some of which are made of metal plates, and other parts of which are made of cast metal conductors.

14. The electrical junction box according to any one of claims 1 to 6, wherein the heat conductive layer is made of an insulating resin material.

15. The electrical connection box according to any one of claims 1 to 6, wherein the bottom plate portion of the case has a first portion which overlaps with the heat conduction layer and a second portion which does not overlap with the heat conduction layer, and the thickness of the first portion is thinner than the thickness of the second portion.

16. The electrical connection box according to any one of claims 1 to 6, further comprising a relay cover that covers the relay, wherein the relay cover presses the relay against the case.

17. The electrical connection box according to claim 16, wherein the terminals of the relay and the busbar are fixed together by screws.

18. The electrical connection box according to claim 17, wherein, in the direction of screw insertion, the terminals of the relay are not covered by the relay cover.

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