阅读说明：本技术 电路结构体 (Circuit structure ) 是由 伊佐治优介 冈本怜也 竹田仁司 于 2020-04-14 设计创作，主要内容包括：提供电路结构体(10),包括：电连接于负载(16)与蓄电池之间的主继电器(14)、与主继电器(14)并联连接的预充电电路(30)、导热部件(44),预充电电路(30)具有与主继电器(14)连接的通电部(60、66),导热部件(44)与通电部(60、66)接触。(Provided is a circuit structure (10) comprising: the battery charging device comprises a main relay (14) electrically connected between a load (16) and the battery, a pre-charging circuit (30) connected in parallel with the main relay (14), and a heat conductive member (44), wherein the pre-charging circuit (30) has energizing portions (60, 66) connected with the main relay (14), and the heat conductive member (44) is in contact with the energizing portions (60, 66).)

1. A circuit structure body, comprising:

the main relay is electrically connected between the load and the storage battery;

a precharge circuit connected in parallel with the main relay; and

a heat-conducting member having a heat-conducting surface,

the precharge circuit has an energizing portion connected to the main relay,

the heat conductive member is in contact with the energizing portion.

2. The circuit structure body according to claim 1,

the circuit structure body includes a case body housing the main relay and the precharge circuit,

the heat-conducting member includes a first heat-conducting plate in a flat plate shape in contact with the case.

3. The circuit structure body according to claim 2,

the heat conductive member includes a second heat conductive sheet in a flat plate shape disposed opposite to the first heat conductive sheet with the case interposed therebetween.

4. The circuit structure body according to claim 2 or 3,

the circuit configuration body includes a holding base that holds the precharge circuit and is fixed to the case,

the current-carrying portion and the first heat-conductive sheet are disposed between the case and the holding base, and the current-carrying portion and the first heat-conductive sheet are pressed against the case by fixing the holding base to the case.

5. The circuit structure body according to claim 4,

the current-carrying portion is constituted by a flat plate-like bus bar,

the bus bar is disposed such that surfaces on both sides of the bus bar in a plate thickness direction abut the holding base and the first heat conductive sheet,

the contact surfaces of the case and the holding base are flat, and the first heat conduction sheet has flexibility.

Technical Field

The present disclosure relates to a circuit structure electrically connected between a load of a vehicle and a battery.

Background

An electric vehicle such as an electric vehicle or a hybrid vehicle is mounted with a power supply device including a circuit structure including a relay for interrupting electrical connection between a battery for running and a load on the vehicle side. For example, patent document 1 discloses a circuit structure provided with a relay that interrupts power supply to a battery to a motor and a generator connected as a load on a vehicle side via an inverter.

Since a very large current of 50A or more flows in the relay used in such a circuit structure when connected, joule heat proportional to the square of the current amount is generated, and the amount of heat generation also increases. In view of this, patent document 1 proposes a structure for dissipating heat of a relay by using an intermediate portion of a bus bar connecting a connection portion of the relay housed in a case and a connection terminal of a battery disposed outside the case. Specifically, the following configurations are disclosed: the intermediate portion of the bus bar extending out of the case housing the relay is brought into contact with the chassis, the housing the entire power supply device, and the like via the insulating heat sink, whereby heat generated by the relay is radiated to the chassis and the housing by heat conduction.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-79093

Disclosure of Invention

Problems to be solved by the invention

The bus bar constituting the current-carrying portion connecting the relay and the battery needs to have a large thickness and a large area so as to be able to withstand a large current. Therefore, in the structure of patent document 1, it is necessary to use a large bus bar and add a path for heat radiation, which causes a problem of an increase in material cost and machining cost. In addition, the large bus bar needs to be extended to another member provided outside the box body for heat dissipation, and the distance between the connection portion of the relay and the heat dissipation portion inevitably increases. Therefore, there is a problem that heat generated by the relay cannot be efficiently dissipated.

Therefore, an object is to provide a circuit structure having a new structure that suppresses an increase in material cost and processing cost and improves heat dissipation efficiency of a relay.

Means for solving the problems

In a power supply device mounted on an electric vehicle such as an electric vehicle or a hybrid vehicle, a capacitor is connected in parallel with a load on the vehicle side, and power can be stably supplied to the load from both the capacitor and a battery. In addition, the circuit structure including a relay (hereinafter, referred to as a main relay) for interrupting the battery and the load includes a precharge circuit in which a precharge relay and a precharge resistor used when precharging the capacitor are connected in series so as to bypass the main relay, in addition to the main relay. In this way, the precharge relay is connected before the main relay is connected, so that the capacitor can be charged in advance, and the connection part of the main relay is prevented from being damaged by a large inrush current flowing through the capacitor when the main relay is connected. The circuit structure of the present disclosure efficiently realizes heat dissipation of the main relay by a new structure using the precharge circuit.

The disclosed circuit structure includes: the battery charging apparatus includes a main relay electrically connected between a load and a battery, a precharge circuit connected in parallel to the main relay, the precharge circuit having an energizing portion connected to the main relay, and a heat conductive member in contact with the energizing portion.

Effects of the invention

According to the present disclosure, a circuit structure having a new structure can be provided that suppresses an increase in material costs and processing costs and improves the heat dissipation efficiency of the relay.

Drawings

Fig. 1 is a perspective view showing a circuit structure according to embodiment 1 of the present disclosure.

Fig. 2 is a diagram schematically showing an electrical configuration of a path from the battery to the load.

Fig. 3 is an exploded perspective view of the circuit structure shown in fig. 1.

Fig. 4 is a plan view of the circuit structure shown in fig. 1.

Fig. 5 is a V-V sectional view of fig. 4.

Detailed Description

Description of embodiments of the present disclosure

First, embodiments of the present disclosure are listed for explanation.

A circuit structure (1) of the present disclosure includes: the battery charging apparatus includes a main relay electrically connected between a load and a battery, a precharge circuit connected in parallel to the main relay, the precharge circuit having an energizing portion connected to the main relay, and a heat conductive member in contact with the energizing portion.

According to the circuit structure of the present disclosure, in the precharge circuit provided in the vicinity of the main relay, the heat conductive member is in contact with at least a partial region of the conducting portion connected to the bus bar connected to the main relay. Therefore, heat of the main relay can be efficiently dissipated through the heat conductive member in the vicinity of the connection portion of the main relay. Further, since the heat conductive member only needs to be in contact with at least a part of the conducting portion of the conventional precharge circuit, it is not necessary to run a large bus bar long for heat dissipation as in the conventional structure, and the heat dissipation structure of the main relay can be realized while suppressing the cost with a simple structure. In addition, even if the surface area of the current-carrying portion of the precharge circuit is enlarged in order to improve heat transfer efficiency or the like, the sectional area is smaller than that of the current-carrying portion connecting the main relay and the battery, so that an increase in cost can be suppressed.

The conducting portion connected to the main relay of the precharge circuit is a portion for electrically connecting the main relay to the precharge relay and/or the precharge resistor. The heat-conducting member in contact with the current-carrying portion may be any member having a thermal conductivity higher than that of air, and for example, an insulating heat-conducting sheet, a heat sink, or the like may be used.

(2) Preferably, the heat conductive member includes a case that houses the main relay and the precharge circuit, and the heat conductive member includes a first heat conductive sheet in a flat plate shape that is in contact with the case. This is because the flat first heat-conductive sheet as the heat-conductive member is in contact with the case, and therefore heat generated in the main relay can be conducted from the current-carrying portion of the precharge circuit to the first heat-conductive sheet and the case without passing through the air layer. As a result, a more efficient heat conduction path of the main relay and a heat dissipation structure based on the heat conduction path can be constructed. Further, since the case and the conducting portion of the precharge circuit have conventional configurations, a heat conduction path of the main relay can be constructed with a simple structure and with high efficiency in space.

(3) Preferably, in the above (2), the heat-conductive member includes a second heat-conductive sheet in a flat plate shape disposed to face the first heat-conductive sheet with the case interposed therebetween. This is because, since the second heat conductive sheet is provided so as to face the first heat conductive sheet with the case interposed therebetween, the heat of the main relay can be further conducted to the outside through the second heat conductive sheet. Therefore, the construction of the heat conduction path of the main relay using a larger area and the heat dissipation of the main relay can be more stable.

(4) Preferably, in the above (2) or (3), a holding base that holds the precharge circuit and is fixed to the case is provided, the current-carrying portion and the first heat-conductive sheet are arranged between the case and the holding base, and the current-carrying portion and the first heat-conductive sheet are pressed against the case by fixing the holding base to the case. This is because the heat conduction path of the main relay including the current-carrying portion, the first heat-conducting fin, and the case can be provided with high space efficiency by utilizing the contact surface between the holding base and the case, which have been used conventionally. The conductive portion and the heat conductive sheet are pressed by the holding base. Thus, loss due to the presence of an air layer or the like in the heat conduction path can be prevented without requiring additional parts, and the stability and performance of the heat conduction path can be effectively improved.

(5) Preferably, in the above (4), the current-carrying portion is formed of a flat-plate-shaped bus bar, the bus bar is disposed such that surfaces on both sides of the bus bar in a plate thickness direction abut against the holding base and the first heat-conductive sheet, the abutting surfaces of the case and the holding base are each flat-plate-shaped, and the first heat-conductive sheet has flexibility. This is because the flat plate-like conductive portion and the first heat conductive sheet can be sandwiched between the flat plate-like case and the contact surface of the holding base without a gap. In particular, since the first heat conductive sheet has flexibility, dimensional tolerances of the case, the holding base, and the bus bar can be absorbed by deformation of the first heat conductive sheet, and the contact area between the members constituting the heat conductive path of the main relay can be reliably maintained, thereby improving the heat conductive performance.

< details of embodiments of the present disclosure >

Specific examples of the circuit structure of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to the examples, but is defined by the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims.

< embodiment 1 >

Embodiment 1 of the present disclosure will be described below with reference to fig. 1 to 5. The circuit structure 10 is mounted on a vehicle (not shown) such as an electric vehicle or a hybrid vehicle, for example. For example, as shown in fig. 2, circuit structure 10 is used to connect a battery for running to vehicle-side load 16 via main relay 14. Here, the battery for running is the battery 12, and is used as a battery for supplying electric power to the motor 22 for running the vehicle. The circuit structure 10 can be arranged in any orientation, but hereinafter, the Z direction is set to the upper side, the Y direction is set to the front side, and the X direction is set to the right side. In addition, in some cases, a plurality of identical components are denoted by reference numerals, and reference numerals are omitted for other components.

< Circuit Structure 10 >

As shown in fig. 2, an output side of the battery 12 that supplies electric power to a motor 22 that runs the vehicle is connected to an input side of the circuit structure 10. A vehicle-side load 16 is connected to the output side of the circuit structure 10. A main relay 14 for connecting the battery 12 to a vehicle-side load 16 is connected between the input side and the output side of the circuit structure 10. A precharge circuit 30 in which a precharge relay 26 and a precharge resistor 28 are connected in series so as to bypass the main relay 14 is connected to the main relay 14 of the circuit structure 10. In embodiment 1 of the present disclosure, as shown in fig. 2, precharge resistor 28 is connected to both the input side and the output side of precharge relay 26. The main relay 14 and the precharge relay 26 are relays that move the movable connection unit in the energized state of the exciting coil to switch the connection unit on/off, and are on/off controlled by a control circuit, not shown.

< storage battery 12 >

The battery 12 has a plurality of rechargeable secondary batteries connected in series to increase the output voltage, for example, 100V to 400V. In addition, a plurality of secondary batteries may be connected in parallel to increase the current capacity. As the secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, a nickel metal hydride battery, or the like can be used. In addition, a capacitor such as an Electric Double Layer Capacitor (EDLC) may be used instead of or in addition to the secondary battery. The secondary battery in this specification further includes a capacitor.

< vehicle side load 16 >

The vehicle-side load 16 is configured by connecting a large-capacity capacitor 18 having a capacitance of 200 μ F to 5000 μ F, for example, in parallel with a DC/AC inverter 20 of the load. When the main relay 14 is switched to the on state in the state where the capacitor 18 is completely discharged, a very large charging current flows instantaneously to charge the capacitor 18. Since an extremely large charging current causes damage to the connection portion of the main relay 14, the precharge circuit 30 is provided to prevent adverse effects due to the charging current. In embodiment 1 of the present disclosure, as shown in fig. 2, a precharge circuit 30 is provided in parallel with the main relay 14. The precharge circuit 30 is connected to the precharge relay 26 in series with the precharge resistor 28 in order to limit the charging current of the capacitor 18. Precharge resistor 28 keeps the charging current of capacitor 18 small in a state where precharge relay 26 and main relay 14 are switched on. The two precharge resistors 28 may have the same or different resistance values. Alternatively, only one of the precharge resistors 28 may be provided.

The vehicle-side load 16 connects the battery 12 to the motor 22 and the generator 24 via the DC/AC inverter 20. The DC/AC inverter 20 converts the direct current of the battery 12 into an alternating current and supplies the alternating current to the motor 22, and converts the alternating current of the generator 24 into a direct current to charge the battery 12. Fig. 2 shows a hybrid vehicle and a plug-in hybrid vehicle. The electric vehicle not equipped with a generator supplies electric power to the motor via the DC/AC inverter 20, and charges the battery block with the motor as a generator or with a separately provided generator during regenerative braking. In embodiment 1 of the present disclosure, the DC/AC inverter 20 is used, but may be a DC/DC converter.

In embodiment 1 of the present disclosure, as shown in fig. 2, the precharge relay 26 is switched to an on state by a control circuit, not shown, to precharge the capacitor 18. After the capacitor 18 is precharged, the main relay 14 is switched to the on state, thereby preventing the connection portion of the main relay 14 from being damaged by the charging current of the capacitor 18.

For example, as shown in fig. 1 and 3, the circuit structure 10 includes a case 32, a main relay 14 disposed in the case 32, and a precharge circuit 30.

< box 32 >

The case 32 is formed by injection molding insulating synthetic resin into a predetermined shape. The synthetic resin constituting the case 32 may include a filler such as glass fiber. For example, as shown in fig. 3, the case 32 has a substantially rectangular case shape that is opened upward as a whole, and includes a bottom wall 34 and a peripheral wall 36 that protrudes upward from an end edge portion of the bottom wall 34. In embodiment 1 of the present disclosure, the outer shape of the case 32 is substantially rectangular when viewed from above. The outer shape of the case 32 is not limited to the shape of the present embodiment.

As shown in fig. 3 and 4, a first fixing portion 40 having a cylindrical shape is provided at four positions along the peripheral wall 36 on the right side of the upper surface 38 of the bottom wall 34 of the case 32. Further, a second fixing portion 42 having a cylindrical shape is provided at four positions along the peripheral wall 36 on the left side of the upper surface 38 of the bottom wall 34 of the case 32 and at a lower height than the first fixing portion 40. Both the fixing portions 40 and 42 are integrally formed with the case 32, and bolts, not shown, are inserted into both the fixing portions 40 and 42.

< first thermally conductive sheet 44 and second thermally conductive sheet 46 >

As shown in fig. 3, two first heat conductive sheets 44 having a substantially rectangular flat plate shape, which constitute a heat conductive member, are provided in the vicinity of the center of the upper surface 38 of the bottom wall 34 of the case 32 with a slight gap therebetween in the front-rear direction. As shown in fig. 5, two second heat conductive sheets 46 in the form of rectangular flat plates constituting the heat conductive member are provided in the vicinity of the center of the lower surface 48 of the bottom wall 34 of the case 32 so as to be spaced apart from each other by a slight gap in the front-rear direction. The first heat conductive sheet 44 and the second heat conductive sheet 46 have substantially the same shape, and the second heat conductive sheet 46 is disposed opposite to the first heat conductive sheet 44 with the case 32 interposed therebetween.

The first thermally conductive sheet 44 and the second thermally conductive sheet 46 are flat in the vertical direction and are made of synthetic resin having a thermal conductivity larger than that of air. The first thermally conductive sheet 44 has flexibility, and the thickness dimension can be changed in accordance with the force applied in the vertical direction.

< main relay 14 >

The main relay 14 has a so-called mechanical structure having a connecting portion and a coil portion, not shown, therein. For example, as shown in fig. 1 and 5, a first power terminal 50 provided on the rear side and a second power terminal 52 provided on the front side are arranged in the front-rear direction on the left side surface of the main relay 14. When a current flows through the first power terminal 50 and the second power terminal 52, heat is generated at the connection portion of the main relay 14 and is conducted to the first power terminal 50 and the second power terminal 52. Screw holes 54 are formed in the first power terminal 50 and the second power terminal 52, respectively (see fig. 5).

As shown in fig. 4, fixing legs 56 having a substantially rectangular shape as viewed from above are provided at the lower end portions of the four corners of the main relay 14 in a protruding manner. An insertion hole 58 is formed in the fixing leg portion 56 in the vertical direction (see fig. 4). The main relay 14 is housed in the right side of the case 32, and the main relay 14 is fixed to the case 32 by inserting a screw, not shown, into the insertion hole 58 in a state where the fixing leg portion 56 is placed on the first fixing portion 40.

As shown in fig. 3, the first current carrying portion 60 formed of a thin bus bar having a substantially L-shape and one end portion of a thick first bus bar 62 having a substantially crank-shape are fastened and fixed to the first power terminal 50. That is, screws, not shown, are inserted through insertion holes 64, 64 provided through the center portions of the first current carrying portion 60 and the one end portion of the first bus bar 62 and screwed into the screw holes 54 of the first power terminal 50, whereby the one end portions are fastened and fixed together. As shown in fig. 3 and 5, the second current passing portion 66 formed of a thin bus bar having a substantially L-shape and one end portion of a thick second bus bar 68 having a substantially crank-shape are fastened and fixed to the second power terminal 52. That is, the screws 70 are inserted through the insertion holes 64, 64 provided through the center portions of the second current passing portion 66 and the one end portion of the second bus bar 68 and screwed into the screw holes 54 of the second power terminal 52, whereby the one end portions are fastened and fixed together. For example, the first bus bar 62 is connected to the input side of the circuit structural body 10, and the second bus bar 68 is connected to the output side of the circuit structural body 10.

As shown in fig. 3 and 5, the other end sides of the first current carrying portion 60 and the second current carrying portion 66 extend parallel to the upper surface 38 of the bottom wall 34 of the case 32 in a state where the main relay 14 is housed in the case 32, and constitute a heat conductive member contact portion 72. Thus, when the main relay 14 is housed and assembled in the case 32, the heat conductive member contact portions 72 of the first current carrying portion 60 and the second current carrying portion 66 are disposed in a state of contact with the first heat conductive sheet 44 placed on the upper surface 38 of the bottom wall 34 of the case 32. Further, the heat-conducting member contact portion 72 is provided with resistance connection portions 74 protruding outward and extending upward.

The current-carrying portions 60 and 66 and the bus bars 62 and 68 are formed by press-working a metal plate material into a predetermined shape. As the metal constituting the current-carrying portions 60, 66 and the bus bars 62, 68, a metal having high thermal conductivity and low electric resistance, such as copper, a copper alloy, aluminum, or an aluminum alloy, can be appropriately selected.

< precharge circuit 30 >

As shown in fig. 3 to 5, the precharge circuit 30 is held on the holding pedestal 76. The holding base 76 is formed by injection molding insulating synthetic resin into a predetermined shape, and has a flat, substantially rectangular plate shape as a whole. The synthetic resin constituting the holding base 76 may include a filler such as glass fiber. Fixing portions 78, which are rectangular when viewed from above, are provided at four corners of the holding base 76. The fixing portion 78 is formed with an insertion hole 80 (see fig. 3) in the vertical direction. As shown in fig. 3, on the upper surface of the holding base 76, a pre-charge resistor attachment 82 is provided so as to protrude upward on the front side and the rear side, and a pre-charge relay attachment 84 is provided so as to protrude upward on the left side. The precharge resistor 28 and the precharge relay 26 are mounted on the precharge resistor mounting portion 82 and the precharge relay mounting portion 84, respectively, and various bus bars including an input bus bar 86 for the precharge relay 26 are mounted from the lower surface of the holding base 76. Thereby, the precharge circuit 30 (see fig. 2) held on the holding pedestal 76 is configured.

< precharge resistor 28 >

For example, as shown in fig. 3, the precharge resistors 28 are rectangular parallelepiped-shaped and elongated in the left-right direction. Pin terminals, not shown, are provided at the left and right ends of the precharge resistor 28 so as to protrude downward.

< precharge relay 26 >

For example, as shown in fig. 3, the precharge relay 26 is a rectangular parallelepiped shape smaller than the main relay 14, and has a so-called mechanical structure having a connection portion and a coil portion, not shown, inside. A plurality of pin terminals (not shown) protrude downward from the lower surface of the precharge relay 26.

< Assembly Process of Circuit Structure 10 >

Next, an example of an assembly process of the circuit structure 10 will be described. The assembly process of the circuit structure 10 is not limited to the following description.

First, the case 32 is prepared. Next, the two first thermally conductive sheets 44 and the two second thermally conductive sheets 46 are cut into a predetermined shape by a known method such as thomson die cutting. Two first heat conductive sheets 44 are attached to predetermined positions on the upper surface 38 of the bottom wall 34 of the case 32, and two second heat conductive sheets 46 are attached to predetermined positions on the lower surface 48 of the bottom wall 34 of the case 32.

The main relay 14 is housed from above in the case 32 to which the heat conductive sheets 44 and 46 are attached. In a state where the fixing leg portion 56 of the main relay 14 is placed on the first fixing portion 40 provided in the case 32, a screw, not shown, is inserted into the insertion hole 58, and the main relay 14 is fixed to the case 32. The other end sides of the first current carrying portion 60 and the second current carrying portion 66 extend parallel to the upper surface 38 of the bottom wall 34 of the case 32 in a state where the main relay 14 is housed and fixed in the case 32, and constitute a heat conductive member contact portion 72. Thus, the heat conductive member contact portion 72 of the first current carrying portion 60 and the second current carrying portion 66 is disposed in contact with the first heat conductive sheet 44 placed on the upper surface 38 of the bottom wall 34 of the case 32.

Next, the holding base 76 holding the precharge circuit 30 is housed from above in the right side of the case 32. In a state where the fixing portion 78 of the holding base 76 is placed on the second fixing portion 42 provided in the case 32, a screw, not shown, is inserted into the insertion hole 80, and the holding base 76 holding the precharge circuit 30 is fixed to the case 32. In this way, the resistance connection portion 74 provided on the other end portion side of the first current carrying portion 60 and the second current carrying portion 66 is connected to the pin terminal, not shown, of the precharge resistor 28 via the relay terminal, not shown, and the circuit structure 10 is completed.

In this state, for example, as shown in fig. 5, the heat-conductive member contact portion 72 and the first heat conductive sheet 44, which are configured by the other end sides of the first current carrying portion 60 and the second current carrying portion 66, are arranged between the contact surfaces 88 and 90 of the case 32 and the holding base 76. That is, the first heat conductive sheet 44 is provided in contact with the heat conductive member contact portion 72 of the first and second current passing portions 60 and 66 of the precharge circuit 30 connected to the bus bars 62 and 68 of the main relay 14. The contact surfaces 88 and 90 of the case 32 and the holding base 76 are both flat plates, and the heat conduction member contact portion 72 is disposed such that the surfaces on both sides in the plate thickness direction of the heat conduction member contact portion 72 are in contact with the holding base 76 and the first heat conduction fin 44, respectively. As a result, the heat-conductive-member contact portion 72 and the first heat conductive sheet 44 are pressed against the case 32 by the holding base 76.

Next, the operation and effects of the present embodiment will be described. According to the present embodiment, in the precharge circuit 30 provided in the vicinity of the main relay 14, the first heat conductive sheet 44 as the heat conductive member is provided in contact with the heat conductive member contact portion 72 that is a part of the first and second current passing portions 60 and 66 connected to the first and second power terminals 50 and 52 of the main relay 14. This allows heat generated in the main relay 14 to be quickly transferred to the vicinity of the main relay 14 via the first heat conductive sheet 44, thereby efficiently dissipating heat from the main relay 14. Further, since the heat conductive member is provided only in the heat conductive member contact portion 72 which is a part of the first and second current passing portions 60 and 66 as it is in the conventional precharge circuit 30, it is not necessary to run a large bus bar long for heat radiation as in the conventional structure. Therefore, with a simple configuration, a heat radiation structure of main relay 14 can be realized while suppressing cost. Even if the surface area of the heat-conductive-member contact portion 72 of the entire first and second current-carrying portions 60, 66 of the precharge circuit 30 is enlarged to improve the heat transfer efficiency, the cross-sectional area is smaller than that in the case where the surface area of the current-carrying portion connecting the main relay 14 and the battery 12 is enlarged as in the related art, and thus an increase in cost can be suppressed.

Further, according to the above configuration, the first heat conductive sheet 44 in a flat plate shape provided so as to be in contact with the heat conductive member contact portion 72 of the first and second current carrying portions 60 and 66 connected to the first and second power terminals 50 and 52 of the main relay 14 in the precharge circuit 30 is held between the heat conductive member contact portion 72 and the bottom wall 34 of the case 32. This allows heat generated by main relay 14 to be conducted to case 32 not through the air layer but through first and second conduction portions 60 and 66 and first heat conduction sheet 44. As a result, a more efficient heat conduction path of main relay 14 and a heat dissipation structure based on the heat conduction path can be constructed. Further, the case 32 and the precharge circuit 30 can construct the heat conduction path of the main relay 14 and the heat radiation structure based on the heat conduction path in a space-efficient manner with a simple structure, as is conventional.

Further, a second heat conductive sheet 46 is provided so as to be disposed opposite to the first heat conductive sheet 44 with the case 32 interposed therebetween. This allows heat of the main relay 14 to be more efficiently transferred to the outside via the second heat conductive sheet 46, and thus, a heat transfer path of the main relay 14 can be constructed using a larger area, and heat dissipation of the main relay 14 can be more stably achieved.

Further, the heat-conductive member contact portion 72 and the first heat conductive sheet 44 are disposed between the contact surfaces 88 and 90 of the holding base 76 and the case 32 by utilizing the gap between the conventional holding base 76 and the case 32. This makes it possible to provide a heat conduction path of the main relay 14 in the gap between the holding base 76 and the case 32 with high space efficiency. The heat-conductive-member contact portion 72 and the first heat conductive sheet 44 are pressed by the fixing force of the holding base 76 to the case 32. This eliminates the need for additional parts, prevents the loss of the heat transfer path due to the presence of an air layer, and effectively improves the stability and performance of the heat transfer path.

Further, according to the above configuration, the flat plate-shaped heat-conductive member contact portion 72 and the first heat conductive sheet 44 can be sandwiched between the flat plate-shaped contact surfaces 88 and 90 of the case 32 and the holding base 76 without a gap. Further, since the first thermally conductive sheet 44 has flexibility, dimensional tolerances of the case 32, the holding base 76, and the thermally conductive member contact portion 72 can be absorbed by deformation of the first thermally conductive sheet 44. Therefore, the contact area between the members constituting the heat conduction path of main relay 14 can be reliably ensured, and the heat conduction performance can be improved.

< modification example >

As described above, embodiment 1 is described in detail as a specific example of the present disclosure, and the present disclosure is not limited by the specific description. Variations, improvements, and the like within a range capable of achieving the object of the present disclosure are included in the present disclosure. For example, the following modifications of the embodiments are also included in the technical scope of the present disclosure.

(1) In the above embodiment, the example in which the heat conductive members (the first heat conductive sheet 44 and the second heat conductive sheet 46) are provided in the first and second current passing portions 60 and 66 connecting the main relay 14 and the precharge resistor 28 in the precharge circuit 30 has been described, but the present invention is not limited thereto. When a current-carrying portion for electrically connecting main relay 14 and precharge relay 26 is used, a heat-conductive member may be provided in the heat-conductive member contact portion.

(2) It is needless to say that a path from main relay 14 to battery 12 may be combined with a structure of a heat conduction path constituting main relay 14. This makes it possible to reduce the size of the heat transfer path of the main relay 14 and additionally use the heat transfer path between the main relay 14 and the battery 12 according to the configuration of the present disclosure using the precharge circuit 30.

(3) As the heat conductive member provided in the first and second current passing portions 60 and 66, any heat conductive member having a thermal conductivity higher than that of air can be used. For example, a heat sink may be used instead of the insulating first thermally conductive sheet 44, or a heat sink may be used in addition to the insulating first thermally conductive sheet 44.

(4) In the above embodiment, the first thermally conductive sheet 44 and the second thermally conductive sheet 46 are divided into two, but may be integrated. This improves the workability of manufacturing and bonding.

(5) In embodiment 1 described above, an example is shown in which the structure of the present disclosure is applied to the circuit structure 10 that interrupts electrical connection between the DC/AC inverter 20, in which the capacitor 18 is connected in parallel, and the battery 12. The circuit structure 10 of the present disclosure can be similarly applied to all circuit structures in which a load connected in parallel with another capacitor and the battery 12 are interrupted.

Description of the reference numerals

10

12.. a storage battery

Main relay

Vehicle side load (load)

A capacitor

DC/AC inverter (load)

A motor

A generator

A pre-charge relay

A pre-charge resistor

Precharge circuit

32

Bottom wall

A peripheral wall

A top surface

A first fixing part

A second fixing part

A first thermally conductive sheet (thermally conductive member)

A second thermally conductive sheet (thermally conductive member)

Lower surface of

A first power terminal

A second power terminal

Screw hole

56.. fixing the legs

58.

60. first electrified part

A first bus bar

Inserting through hole

66.. second electrifying part

68.. second busbar

Screw (1)

A thermally conductive member abutment

74

76.

78.. fixing part

80.

82.. Pre-charging resistor Assembly

A pre-charge relay assembly

86.. bus bar for input

88.. abutment surface

90..