CN110024172B

CN110024172B - Relay unit

Info

Publication number: CN110024172B
Application number: CN201780073763.0A
Authority: CN
Inventors: 池尻徳贵; 江岛巧; 川口清史; 小田麻衣子; 铃木健文; 小原芳和
Original assignee: Sumitomo Wiring Systems Ltd; Toyota Motor Corp
Current assignee: Sumitomo Wiring Systems Ltd; Toyota Motor Corp
Priority date: 2016-12-05
Filing date: 2017-12-05
Publication date: 2022-01-11
Anticipated expiration: 2037-12-05
Also published as: CN110024172A; WO2018105610A1

Abstract

The relay unit includes: a first bus bar; a relay electrically connected to the first bus bar; and an equipment cover covering the first bus bar and the relay. The equipment cover is box-shaped with a closed upper end, and comprises an upper part with an opening formed at the lower end and a lower part combined with the upper part in a mode of closing the opening of the upper part. The lower member is formed of a resin having a higher heat conductivity than the upper member. The first bus bar is connected to the lower member so as to be capable of heat transfer via a first inner heat conductive sheet disposed between the first bus bar and the lower member.

Description

Relay unit

Technical Field

The present invention relates to a relay unit housed in a battery case.

Background

Vehicles such as electric vehicles and hybrid vehicles are equipped with electric motors for driving the vehicles. Further, a generator may be mounted depending on the vehicle. Such an electric motor or a rotating electric machine as a generator is connected to a battery via an inverter. At this time, a relay is connected between the inverter, which is a load of the battery, and the relay is controlled by the control device, thereby switching the electrical connection state between the battery and the inverter.

Patent document 1 describes a configuration in which a relay is housed inside an electrical installation case including other electrical installation elements in a vehicle. One end of a bus bar is electrically connected to a contact of the relay, and the other end of the bus bar is electrically connected to an output terminal of the battery block outside the electrical installation case. The intermediate portion of the bus bar is connected to a chassis constituting the vehicle via an insulating heat sink on the outside of the electrical equipment case. Patent document 1 also describes that the bus bar may be connected to a case that houses the battery system, not only to the chassis. Thus, the heat generated by the relay can be dissipated by conducting heat to the chassis or other housing.

Prior art documents

Patent document

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

Disclosure of Invention

Problems to be solved by the invention

However, the position at which the bus bar extending from the electrical installation case is connected to the chassis or the case housing the battery system is far apart from the contact point inside the relay, which is likely to generate heat. This increases the distance between the contact and the heat dissipation portion of the relay, and may make it difficult to dissipate heat from the relay. Therefore, there is a possibility that the cooling efficiency of the relay is lowered.

The purpose of the present invention is to improve the cooling efficiency of a relay in a relay unit housed in a battery case.

Means for solving the problems

The relay unit of the present invention is housed in a battery case, and includes: a first bus bar; a relay electrically connected to the first bus bar; and a device cover that covers the first bus bar and the relay, the device cover having a box shape with a closed upper end, the device cover including an upper member having an opening formed at a lower end thereof and a lower member coupled to the upper member so as to close the opening of the upper member, the lower member being formed of a resin having a higher heat conductivity than the upper member, the first bus bar being connected to the lower member so as to be thermally transferable via a first inner thermally conductive sheet disposed between the first bus bar and the lower member.

According to the relay unit of the present invention, the first bus bar located inside the equipment cover is connected to the lower member of the equipment cover in a heat-transferable manner. Thus, when the lower member is connected to the battery case so as to be capable of heat transfer, the distance from the contact of the relay to the battery case, which is a heat dissipation portion, can be easily reduced in the heat dissipation path of the relay. Also, the heat capacity of the battery case increases. This makes it easy to dissipate heat generated by the relay to a portion having a large heat capacity in a short distance, and therefore, the cooling efficiency of the relay can be improved. Further, the first bus bar and the lower member are connected via the first inner thermally conductive sheet. Thus, even when the lower member is formed of a material that is easily broken, the lower member can be prevented from being broken by the collision of vibration with the first bus bar. Further, the lower member is formed of a resin having a higher heat conductivity than the upper member. This eliminates the need to improve the heat transfer property of the upper member, and thus can reduce the cost of the equipment cover and improve the heat dissipation when the heat transfer path including the lower member is used.

In the relay unit according to the present invention, it is preferable that the relay unit includes an outer thermally conductive sheet disposed below the lower member, and the first bus bar is connected to the outer thermally conductive sheet through the first inner thermally conductive sheet and the lower member so as to be thermally transferable.

According to the above-described preferred configuration, even when the lower member is formed of a material that is easily broken when the lower member is connected to the battery case via the outer heat conductive sheet on the lower side of the lower member of the device cover, the lower member can be prevented from being broken by the collision of vibration with the battery case.

In the relay unit according to the present invention, it is preferable that the relay unit includes a second bus bar covered with the device cover, the relay is electrically connected to the first bus bar and the second bus bar between the first bus bar and the second bus bar, a first concave portion and a second concave portion partitioned by an insulating wall are formed on an upper surface of the lower member, the first inner heat conductive sheet is disposed in the first concave portion, the first bus bar is disposed in the first concave portion so as to overlap with the first inner heat conductive sheet on an upper side thereof, the second inner heat conductive sheet is disposed in the second concave portion so as to overlap with the second bus bar in the second concave portion on an upper side thereof, and the first bus bar is connected to the outer heat conductive sheet through the first inner heat conductive sheet and the lower member so as to be capable of heat transfer, and the second bus bar is connected to the outer heat conductive sheet so as to be capable of heat transfer via the second inner heat conductive sheet and the lower member.

According to the above preferred configuration, the first inner thermally conductive sheet contacting the first bus bar on the lower side and the second inner thermally conductive sheet contacting the second bus bar on the lower side are disposed separately from the first recess and the second recess partitioned by the insulating wall. Thus, even when moisture enters the device cover or water is condensed from water vapor in the device cover and accumulates in the lower end portion of the device cover, a short circuit between the first bus bar and the second bus bar can be prevented outside the relay.

In the relay unit according to the present invention, it is preferable that the outer thermally conductive sheet is bonded to a lower surface of the lower member, and a sheet protection wall protruding downward is formed in a portion of the lower surface of the lower member, the portion facing at least a part of an outer peripheral surface of the outer thermally conductive sheet.

According to the above preferred configuration, when the relay unit including the device cover and the outer heat conductive sheet is transported, it is possible to prevent the outer heat conductive sheet from being peeled off from the lower member by an external object or a person coming into contact with the outer heat conductive sheet.

In the relay unit according to the present invention, it is preferable that the outer thermally conductive sheet has a rectangular shape when viewed from one side in the thickness direction, the sheet protection wall has a rectangular cross-sectional shape so as to surround the outer thermally conductive sheet, and the height of the sheet protection wall is larger than the thickness of the outer thermally conductive sheet.

According to the preferred configuration described above, peeling of the outer heat conductive sheet from the cover lower member can be further suppressed.

In the relay unit according to the present invention, it is preferable that the sheet protection wall has a cutout formed in an outer peripheral surface thereof including a lower end of the outer thermally conductive sheet so as to be partially exposed in a circumferential direction.

According to the above preferred configuration, when the surface film is attached to the lower surface of the outer heat conductive sheet during conveyance of the relay unit including the device cover and the outer heat conductive sheet, the surface film can be easily detached from the outer heat conductive sheet through the slit at the end of conveyance.

Effects of the invention

According to the relay unit of the present invention, the cooling efficiency of the relay can be improved.

Drawings

Fig. 1 is a circuit diagram showing a vehicle-mounted battery relay connection structure according to an embodiment.

Fig. 2 is a cross-sectional view showing a battery module and an equipment cover disposed in a battery case in the embodiment.

Fig. 3 is a cross-sectional view showing a state in which a first bus bar in an equipment cover is connected to a case lower member constituting a battery case in the embodiment.

Fig. 4 is a cross-sectional view showing a state in which a first bus bar in an equipment cover is connected to a case lower member constituting a battery case in another example of the embodiment.

Fig. 5 is a cross-sectional view showing a state in which a first bus bar in an equipment cover is connected to a case lower member constituting a battery case in another example of the embodiment.

Fig. 6 is a cross-sectional view showing the relay unit including the device cover and the relay taken out from fig. 5.

Fig. 7 is a cross-sectional view showing a state in which a second bus bar in the device cover is connected to a case lower member constituting the battery case in another example of the embodiment.

Fig. 8 is a cross-sectional view showing a state where an outer heat conductive sheet is peeled off from an apparatus cover in a relay unit constituting a battery relay connection structure according to another example of the embodiment.

Fig. 9 is a cross-sectional view showing a relay unit constituting a battery relay connection structure according to another example of the embodiment.

Fig. 10 is a view seen in the direction of arrow a of fig. 9.

Fig. 11 is a cross-sectional view showing a state in which the first bus bar and the second bus bar in the device cover are connected to a case lower member constituting the battery case in another example of the embodiment.

Fig. 12 is an enlarged view of a portion B of fig. 11.

Fig. 13 is a view, partially omitted and viewed from below, of a relay unit constituting a battery relay connection structure according to another example of the embodiment, with a cover lower member of an equipment cover removed.

Fig. 14 is a perspective view showing a part of the first bus bar and the second bus bar arranged on the lower member of the device cover in the relay unit constituting the battery relay connection structure according to another example of the embodiment.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The shape, material, and number described below are illustrative examples, and may be appropriately changed according to the specification of a vehicle including the in-vehicle battery relay connection structure. In the following, the same elements are denoted by the same reference numerals throughout the drawings. In the description herein, the reference numerals described above are used as necessary.

In the following, a case will be described where the load of the battery is an inverter connected to the motor, but the embodiment is not limited to such a configuration, and the load may be another electric element.

Fig. 1 is a circuit diagram showing a vehicle-mounted battery relay connection structure 10 according to an embodiment. Hereinafter, the in-vehicle battery relay connection structure 10 will be described as a battery relay connection structure 10. The battery relay connection structure 10 is mounted on a vehicle. The vehicle is an electric vehicle or a hybrid vehicle including a motor (not shown) as a rotating electrical machine as a drive source of the vehicle. When the vehicle is a hybrid vehicle, the vehicle includes an engine as a drive source in addition to a motor. A battery module 12 as a battery is connected to the motor via an inverter 50. The battery modules 12 constitute the battery relay connection structure 10. A positive relay 14 and a negative relay 15 are connected between the battery module 12 and the inverter 50.

Specifically, the battery relay connection structure 10 includes the battery module 12, the

first bus bars

20a, 20b, the

second bus bars

22a, 22b, the positive relay 14, the negative relay 15, the device cover 30, and the battery case 40. The battery module 12 is configured by electrically connecting a plurality of battery cells in series. The battery module 12 may include a structure in which a part of the battery cells are connected in parallel. The battery module 12 is housed in the battery case 40.

Fig. 2 is a cross-sectional view showing the battery module 12 and the device cover 30 disposed in the battery case 40 in the embodiment. The battery case 40 is configured by joining the case lower member 41 and the case upper member 45. The case lower member 41 includes a bottom plate 42 and an outer peripheral wall 43 standing from the outer peripheral edge of the bottom plate 42. The case upper member 45 includes a top plate 46 and an outer peripheral wall 47 connected to the outer periphery of the top plate 46 and projecting downward. In a state where the case upper member 45 is fitted to the upper side of the case lower member 41 from the outside, the case upper member 45 is coupled to the case lower member 41 by fastening means (not shown) such as bolts. The case upper member 45 and the case lower member 41 are both made of metal such as iron or aluminum. The case lower member 41 is formed of a die cast of an aluminum alloy, for example. This can improve the heat dissipation of the case lower member 41.

The battery module 12,

first bus bars

20a and 20b,

second bus bars

22a and 22b, a positive relay 14, a negative relay 15, and an equipment cover 30, which are shown in fig. 1 and 3 and described later, are housed inside the battery case 40. The device cover 30 covers the

first bus bars

20a and 20b, the

second bus bars

22a and 22b, the positive relay 14, and the negative relay 15, that is, from the outside.

As shown in fig. 2, the battery module 12 is fixed to the bottom plate portion 42 of the case lower member 41 of the battery case 40. At this time, the plate-like heat insulator 48 and the heat transfer member 49 are stacked in this order on the upper side of the bottom plate portion 42, and the battery module 12 is disposed on the upper side of the heat transfer member 49. The heat transfer member 49 is configured by sealing a heat absorbing gel, which is a heat absorbing agent as a refrigerant, in a housing made of an aluminum sheet. The heat transfer member 49 absorbs heat transferred from the battery module 12 to a part of the heat absorbing gel through the housing, and diffuses and dissipates the heat to the entire heat absorbing gel. This can improve the heat insulating effect between the battery module 12 and the case lower member 41 by the heat insulating material 48. The heat transfer member 49 disposed between the battery module 12 and the case lower member 41 may be omitted.

In a state where the battery case 40 is fixed to a vehicle body (not shown), a bottom portion of the case lower member 41 of the battery case 40 is exposed to the outside of the vehicle. Thus, when the vehicle is traveling, the case lower member 41 can be cooled by the traveling wind flowing in the direction of arrow α in fig. 2. Since the traveling wind is usually 60 ℃ or less, the temperature of the battery case 40, which may be higher than 60 ℃, can be lowered by the traveling wind. The battery case 40 is not limited to the configuration in which the case lower member 41 is exposed to the outside of the vehicle, and may be configured to cool the battery case 40 by supplying cooling air to the periphery of the battery case 40 through a duct by driving a blower motor or the like, for example.

The device cover 30 is fixed to the upper side of the case lower member 41 of the battery case 40. The device cover 30 is a structure called a junction BOX, and is formed of resin. The detailed structure of the device cover 30 will be described later with reference to fig. 3. Returning to fig. 1,

first bus bars

20a and 20b,

second bus bars

22a and 22b, positive relay 14, and negative relay 15 are disposed inside device cover 30. Each of the

relays

14 and 15 is configured by housing a relay main body inside a relay case 16 made of an insulating material such as resin. The relay body includes 2 fixed contacts P1 and P2, a movable piece R that can be brought into contact with and separated from the fixed contacts P1 and P2, and an excitation coil (not shown) that switches the connection state between the movable piece R and the fixed contacts P1 and P2. The 2 relay terminals T1 and T2 electrically connected to the fixed contacts P1 and P2 of the relay main body are exposed to the outside of the relay case 16 of the

relays

14 and 15.

In the positive and

negative relays

14 and 15, heat is easily generated near the internal fixed contacts P1 and P2. The internal contacts P1 and P2 are connected to relay terminals T1 and T2, and bus bars described later are connected to the relay terminals T1 and T2. Therefore, in the embodiment, as described later, heat is easily radiated to the portions of the bus bars close to the relay terminals T1 and T2, thereby improving the cooling performance of the

relays

14 and 15.

Specifically, in the positive relay 14 and the negative relay 15, one ends of the

first bus bars

20a and 20b are connected to the relay terminals T1 on the battery module 12 side, respectively. The other ends of the

first bus bars

20a and 20b are connected to battery side connector terminals T3 and T4 attached to the equipment cover 30. The battery side connector terminal T3 connected to the positive relay 14 and the positive output terminal Tp of the battery module 12 are connected by a wire L1 via the charging plug SP.

The battery side connector terminal T4 connected to the negative relay 15 and the negative output terminal Tn of the battery module 12 are connected by a wire L2. Thereby, the positive output terminal Tp of the battery module 12 is electrically connected to the first bus bar 20a, and the negative output terminal Tn of the battery module 12 is electrically connected to the first bus bar 20 b. The charging plug SP can be manually opened and closed by inserting and removing the grip portion into and from the housing.

In the positive relay 14 and the negative relay 15, one ends of the

second bus bars

22a and 22b are connected to the relay terminals T2 on the inverter 50 side, respectively. The other ends of the

second bus bars

22a and 22b are connected to inverter-side connector terminals T5 and T6 attached to the equipment cover 30. A part of the device cover 30 is integrally attached to the case lower member 41 (fig. 1) of the battery case 40, and the 2 inverter-side connector terminals T5 and T6 are exposed to the outside of the case lower member 41 through the integrated part. The 2 inverter-side connector terminals T5 and T6 are connected to a positive input terminal T7 and a negative input terminal T8 of the inverter 50, which are disposed separately from the battery case 40, by 2 wires L3 and L4. Thereby, the positive input terminal T7 of the inverter 50 is electrically connected to the second bus bar 22a, and the negative input terminal T8 of the inverter 50 is electrically connected to the second bus bar 22 b.

The

relays

14 and 15 switch the energization and the stoppage of the exciting coil of the relay main body, thereby switching the electrical connection state between the battery module 12 and the inverter 50. The switching of the

relays

14 and 15 is controlled by a control device (not shown).

Next, a heat dissipation structure of the

relays

14 and 15 using the

bus bars

20a, 20b, 22a, and 22b will be described with reference to fig. 3. Fig. 3 is a cross-sectional view showing a state in which the first bus bar 20a in the device cover 30 is connected to the case lower member 41 constituting the battery case 40 in the embodiment. In fig. 3, only the first bus bar 20a connected to the positive relay 14 among the 4

bus bars

20a, 20b, 22a, 22b shown in fig. 1 is shown. Hereinafter, the positive relay 14 may be referred to as a relay 14.

The device cover 30 has a substantially box-like shape with a closed upper end, and an opening formed at a lower end. An outward flange 31 is formed at the periphery of the opening at the lower end of the equipment cover 30. In the battery case 40, the flange 31 of the device cover 30 is superimposed on the bottom plate portion 42 of the case lower member 41. In this state, the screw portion of the bolt 32 fixed to the case lower member 41 penetrates the flange 31 upward, and the nut 33 is coupled to the screw portion protruding from the upper surface of the flange 31. Thereby, the device cover 30 is fixed to the case lower member 41. A protruding portion 35 protruding inward is formed on the lower side surface of the top plate portion 34 located at the upper end of the device cover 30, and a bus bar holding claw 35a is formed at the lower end portion thereof. For example, the bus bar holding claw 35a is bent vertically at its lower end and engages and holds the first bus bar 20a on its upper side.

The relay case 16 is fixed to the lower side surface of the top plate portion 34 of the device cover 30. The relay terminal T1 of the relay main body projects toward one lateral side (the left side in fig. 3) of the relay case 16. One end of the first bus bar 20a is connected to the relay terminal T1 on the outside of one lateral side of the relay case 16. The intermediate portion of the first bus bar 20a is led out to the other lateral side (right side in fig. 3) of the relay case 16 through the lower side of the relay case 16 in the lateral direction (left-right direction in fig. 3). The other end portion of the first bus bar 20a is held by a bus bar holding claw 35a formed in the equipment cover 30, and the other end portion of the first bus bar 20a is connected to a battery side connector terminal T3 exposed to the outside of the equipment cover 30 (fig. 1). One end of a wire L1 (fig. 1) electrically connected to the battery module 12 outside the device cover 30 is connected to the battery-side connector terminal T3.

The intermediate portion of the first bus bar 20a is sandwiched between the lower surface of the relay case 16 and the upper surface of the case lower member 41 of the battery case 40 via 2 insulating heat

conductive sheets

36 and 37 on the upper and lower sides. The lower heat conductive sheet 37 corresponds to the inner heat conductive sheet. Thereby, the intermediate portion of the first bus bar 20a is connected to the relay case 16 via the upper heat conductive sheet 36 so as to be able to transfer heat. The intermediate portion of the first bus bar 20a is connected to the case lower member 41 via the lower thermally conductive sheet 37 so as to be thermally transferable. The upper thermally conductive sheet 36 between the intermediate portion of the first bus bar 20a and the relay case 16 may be omitted, and the intermediate portion of the first bus bar 20a may directly contact the lower surface of the relay case 16. This also allows heat to be transferred from the relay case 16 to the intermediate portion of the first bus bar 20 a. In the present specification, "connected so as to be capable of heat transfer" includes a case where 2 members are connected via 1 or more members having heat conductivity and a case where 2 members are directly contacted to each other to be heat-transferred.

In the battery relay connection structure 10 described above, the heat generated at the contact inside the relay 14 is formed as a heat radiation path that is sequentially transmitted as indicated by the broken-line arrow in fig. 3, as the contact inside the relay → the relay terminal T1 → the first bus bar 20a → the lower heat conductive sheet 37 → the case lower member 41. The heat transferred to the case lower member 41 is transferred (dissipated) to the outside air. In this way, the first bus bar 20a located inside the equipment cover 30 is connected to the battery case 40 so as to be able to transfer heat, and therefore, in the heat radiation path of the relay 14, the distance from the contact of the relay 14 to the case lower member 41 as the heat radiation portion is easily reduced. The case lower member 41 is larger than the device cover 30, and has a large heat capacity. This makes it easy to dissipate heat generated by the relay 14 to a portion having a large heat capacity at a short distance, and therefore, the cooling efficiency of the relay 14 can be improved.

On the other hand, in the case of the structure described in patent document 1, the intermediate portion of the bus bar connected to the relay is connected to a chassis constituting the vehicle or a case housing the battery system, outside the electrical installation case corresponding to the equipment cover. In the case of this structure, the distance of the heat radiation path from the relay to the portion having a large heat capacity is likely to increase. This makes it difficult to improve the cooling efficiency of the relay.

Further, according to the embodiment, since heat is transferred from the relay case 16 to the first bus bar 20a via the upper heat conductive sheet 36 or directly, the cooling efficiency of the relay 14 can be further improved.

Further, the device cover 30 is fastened to the case lower member 41 by fastening means including bolts and nuts, whereby the thermally

conductive sheets

36 and 37 can be compressed between the relay case 16 and the case lower member 41 via the first bus bar 20 a. Accordingly, the thermally

conductive sheets

36 and 37 can be brought into contact with each other with high adhesion between the relay case 16, the first bus bar 20a, and the case lower member 41, and therefore, the heat transfer performance can be further improved.

In fig. 3, the heat dissipation structure including only the first bus bar 20a connected to the positive electrode relay 14 among the 4

bus bars

20a, 20b, 22a, and 22b shown in fig. 1 is described, but the heat dissipation structure is configured similarly for the

other bus bars

20b, 22a, and 22 b. At this time, one end of the second bus bar 22a (fig. 1) may be connected to a relay terminal of the positive relay 14 that protrudes to the other side (right side in fig. 3) in the lateral direction. In this case, the intermediate portion of the second bus bar 22a may pass through the lower side of the relay case 16, and the other end side portion of the second bus bar 22a may be led out to the opposite side (the left side in fig. 3) to the other end side portion of the first bus bar 20 a. Thereby, all the bus bars connected to the positive relay 14 and the negative relay 15 are connected to the case lower member 41 of the battery case 40 so as to be able to transfer heat. Only one of the first bus bar and the second bus bar may be connected to the case lower member 41 so as to be capable of heat transfer.

Fig. 4 is a cross-sectional view showing a state in which the first bus bar 20a in the device cover 30 is connected to the case lower member 41 constituting the battery case 40 in another example of the embodiment. In another example of the configuration shown in fig. 4, the facility cover 30 includes a cover lower member 38 disposed so as to close the opening at the lower end, based on the configurations shown in fig. 1 to 3. The cover lower member 38 is formed in a plate shape by a resin having high heat conductivity. The intermediate portions of the

first bus bars

20a, 20b are sandwiched between the relay case 16 and the cover lower member 38 via 2 heat

conductive sheets

36, 37 on both the upper and lower sides. Further, the second heat conductive sheet 39 made of an insulating material such as resin is sandwiched between the lower surface of the cover lower member 38 and the case lower member 41 of the battery case 40. The second heat conductive sheet 39 corresponds to an outer heat conductive sheet. Thus, the heat generated at the contact inside the relay 14 is transmitted in sequence as indicated by the broken-line arrow in fig. 4, as the contact inside the relay → the relay terminal T1 → the first bus bar 20a → the lower heat conductive sheet 37 → the cover lower member 38 → the second heat conductive sheet 39 → the case lower member 41. The heat transferred to the case lower member 41 is transferred (radiated) to the outside air.

According to the above configuration, since the cover lower member 38 made of resin and the second thermally conductive sheet 39 made of insulating material are disposed between the case lower member 41 and the first bus bar 20a, the insulation between the first bus bar 20a and the case lower member 41 can be further improved. In the case of the structure of fig. 4, the thermally conductive sheet 36 on the upper side of the first bus bar 20a can be omitted as in the structures of fig. 1 to 3. In fig. 4, only the heat dissipation structure including the first bus bar 20a connected to the positive electrode relay 14 among the 4

bus bars

20a, 20b, 22a, and 22b shown in fig. 1 is described, but the heat dissipation structure is similarly configured for the

other bus bars

20b, 22a, and 22 b. Further, only one of the first bus bar and the second bus bar may be connected to the case lower member 41 so as to be capable of heat transfer. The other structures and functions are the same as those of fig. 1 to 3.

Fig. 5 is a cross-sectional view showing a state in which the first bus bar 20a in the device cover 60 is connected to the case lower member 41a constituting the battery case 40a in another example of the embodiment. Fig. 6 is a cross-sectional view of the relay unit 13 including the device cover 60 and the positive relay 14 taken out from fig. 5. Fig. 7 is a sectional view showing a state where second bus bar 22a in device cover 60 is connected to case lower member 41 a.

In the structure of this example, the battery case 40a constituting the battery relay connection structure is formed by overlapping and joining the case upper member 45 on the upper surface of the flat case lower member 41 a. Specifically, the case lower member 41a is formed of metal such as iron or aluminum, as in the above-described examples. The case lower member 41a has a substantially rectangular shape when viewed from above, and an outer peripheral wall 51 is formed over the entire periphery of the outer peripheral edge of the upper surface. A recess 52 is formed in the upper surface of the case lower member 41a inside the outer peripheral wall 51. In addition, projections 53 having a rectangular cross section are formed to project from a plurality of positions on the bottom surface of the recess 52. Each projection 53 is formed so as to face the lower side of the device cover 60 of each of the positive relay 14 and the negative relay 15 (fig. 1). The entire outer peripheral surface of each projection 53 is surrounded by the recess 52. As described later, each protrusion 53 is pressed against the cover lower member 61 constituting the device cover 60 via the outer heat conductive sheet 65. The case upper member 45 is overlapped on the upper surface of the outer peripheral wall 51 of the case lower member 41a and is coupled thereto by fastening means (not shown) such as bolts. Thus, the battery case 40a blocks the internal space from the outside to form a waterproof structure.

A positive and negative relay unit 13 is fixed to the inside of the battery case 40 a. The configuration of the negative relay unit is the same as that of the positive relay unit 13, and therefore the positive relay unit 13 will be described below. As shown in fig. 6 and 7, the relay unit 13 includes an equipment cover 60, and a positive electrode relay 14, a first bus bar 20a, a second bus bar 22a, a first inner thermally conductive sheet 66, a second inner thermally conductive sheet 67, and an outer thermally conductive sheet 65, which are disposed inside the equipment cover 60.

The equipment cover 60 is configured by coupling a cover upper member 62 and a cover lower member 61. The cover upper member 62 has a substantially box-like shape with an upper end closed by a top plate 63, and an opening at a lower end. The cover lower member 61 is substantially flat plate-shaped, and is coupled to the cover upper member 62 by fastening means (not shown) such as bolts so as to close the opening at the lower end of the cover upper member 62.

The cover upper member 62 is made of an insulating resin. On the other hand, the cover lower member 61 is made of a resin having a higher heat conductivity than the cover upper member 62. For example, the cover lower member 61 is preferably made of a resin having a thermal conductivity 5 times or more that of the resin forming the cover upper member 62. For example, the thermal conductivity of the resin forming the cover upper member 62 is set to about 0.2W/mK, and the thermal conductivity of the resin forming the cover lower member 61 is set to 1.0 to 3.5W/mK. This eliminates the need to improve the heat transfer property of the cover upper member 62, and therefore, the heat dissipation property when the heat transfer path including the cover lower member 61 is used can be improved while suppressing the cost of the equipment cover 60. For example, the cover lower member 61 may be made of a material having improved thermal conductivity by filling a nylon resin with a filler. Further, as a material forming the cover upper member 62, polybutylene terephthalate resin (PBT) can be used. The cover upper member 62 is coupled to the case lower member 41a of the battery case 40a by a fastening member (not shown) such as a bolt penetrating a flange portion (not shown) formed on the outer periphery of the lower end.

Similarly to the configurations of the respective examples shown in fig. 3 and 4, one end of the first bus bar 20a is connected to the relay terminal T1 outside one longitudinal side surface (left side surface in fig. 5 and 6) of the relay case 16. The longitudinal intermediate portion of the first bus bar 20a passes through the lower side of the relay case 16 in the longitudinal direction of the relay case (the left-right direction in fig. 5 and 6) and is led out to the other longitudinal side of the relay case (the right side in fig. 5 and 6). The other end portion of the first bus bar 20a is coupled to the top plate portion 63 of the cover upper member 62 together with one end portion of an intermediate bus bar (not shown) on the other longitudinal side of the relay case 16. The other end of the intermediate bus bar is connected to a battery side connector terminal T3 (fig. 1) exposed to the outside of the device cover 60.

On the other hand, as shown in fig. 7, one end of the second bus bar 22a is connected to the relay terminal T2 outside one side surface (left side surface in fig. 7) in the longitudinal direction of the relay case 16. The intermediate portion of the second bus bar 22a in the longitudinal direction enters the lower side of the relay case 16, extends in the width direction (front-back direction of the paper surface of fig. 7) orthogonal to the longitudinal direction on the lower side of the relay case, and is led out to one side in the width direction of the relay case (back side of the paper surface of fig. 7). The other end portion of the second bus bar 22a is connected to an inverter-side connector terminal T5 (fig. 1) exposed to the outside of the device cover 60 on one side in the width direction of the relay housing 16. Thus, the positive electrode relay 14 is electrically connected between the first bus bar 20a and the second bus bar 22a to the first bus bar 20a and the second bus bar 22a, respectively.

Returning to fig. 5 and 6, the first inner thermally conductive sheet 66 is an insulating resin sheet having high thermal conductivity, and is sandwiched between the lower end surface of the first bus bar 20a and the cover lower member 61. The first inner thermally conductive sheet 66 is preferably formed of a non-silicone resin material. Accordingly, the first inner heat conductive sheet 66 does not generate siloxane gas even when the temperature rises during use, and therefore, contact defects of the relay due to siloxane gas can be prevented.

As shown in fig. 7, the second inner heat conductive sheet 67 is an insulating resin sheet having high heat conductivity, and is sandwiched between the lower end surface of the second bus bar 22a and the cover lower member 61. The second inner heat conductive sheet 67 is also preferably formed of a non-silicone resin material, similarly to the first inner heat conductive sheet 66. The first inner heat conductive sheet 66 and the second inner heat conductive sheet 66 have lower surface hardness than the cover lower member 61. The first inner heat conductive sheet 66 and the second inner heat conductive sheet 67 can be formed using, for example, acrylic resin having low hardness. The first inner heat conductive sheet 66 and the second inner heat conductive sheet 67 are disposed apart from each other.

The outer heat conductive sheet 65 is a resin sheet having high heat conductivity, and is sandwiched between the cover lower member 61 and the upper surface of the projection 53 formed on the case lower member 41a of the battery case 40 a. The outer heat conductive sheet 65 has a rectangular shape when viewed from one side in the thickness direction. The outer heat conductive sheet 65 has substantially the same size as the outer shape of the upper surface of the projection 53 of the case lower member 41a, for example. The outer heat conductive sheet 65 has a lower surface hardness than the cover lower member 61. For example, the outer heat conductive sheet 65 may be formed of the same material as the inner heat

conductive sheets

66 and 67.

When the battery case 40a and the relay unit 13 are viewed from below, the outer heat conductive sheet 65 is disposed so as to overlap the first inner heat conductive sheet 66 and the second inner heat conductive sheet 67 at least partially through the cover lower member 61. The cover lower member 61 is not in direct contact with the case lower member 41a, and is connected to the case lower member 41a via the outer heat conductive sheet 65. At this time, the protrusion 53 of the case lower member 41a is pressed against the cover lower member 61 via the outer thermally conductive sheet 65. As shown in fig. 6, the outer heat conductive sheet 65 is bonded to the lower surface of the cover lower member 61, thereby forming the relay unit 13. Thus, the first bus bar 20a is connected to the outer heat conductive sheet 65 through the first inner heat conductive sheet 66 and the cover lower member 61 so as to be able to transfer heat. The second bus bar 22a is connected to the outer heat conductive sheet 65 through the second inner heat conductive sheet 67 and the cover lower member 61 so as to be capable of heat transfer.

Therefore, the first bus bar 20a is connected to the cover lower member 61 via the first inner heat conductive sheet 66 so as to be able to transfer heat, and can transfer heat from the cover lower member 61 to the outer heat conductive sheet 65 and the battery case 40a, which are the other lower members. Accordingly, the second bus bar 22a is connected to the cover lower member 61 via the second inner heat conductive sheet 67 so as to be capable of heat transfer, and heat can be transferred from the cover lower member 61 to the outer heat conductive sheet 65 and the battery case 40 a.

According to the above configuration, heat generated at the contact inside the positive electrode relay 14 is transmitted to the case lower member 41a as indicated by a broken line arrow in fig. 5. Specifically, heat is transferred in the order of the contact inside the relay → the relay terminal T1 → the first bus bar 20a → the first inner heat conductive sheet 66 → the cover lower member 61 → the outer heat conductive sheet 65 → the case lower member 41 a. As indicated by the broken-line arrows in fig. 7, heat is transferred in the order of the contact inside the relay → the relay terminal T2 → the second bus bar 22a → the second inner heat conductive sheet 67 → the cover lower member 61 → the outer heat conductive sheet 65 → the case lower member 41 a. Then, the heat transferred to the case lower member 41a is transferred (radiated) to the outside, whereby the heat of the relay can be released.

Further, according to the relay unit 13 described above, when the cover lower-side member 61 is connected to the battery case 40a so as to be able to transfer heat, the distance from the contact of the relay to the battery case 40a as the heat dissipation portion is easily reduced in the heat dissipation path of the relay. Also, the heat capacity of the battery case 40a increases. This makes it easy to dissipate heat generated by the relay to a portion having a large heat capacity in a short distance, and therefore, the cooling efficiency of the relay can be improved. The first bus bar 20a and the second bus bar 22a are connected to the cover lower member 61 through the first inner thermally conductive sheet 66 or the second inner thermally conductive sheet 67 so as to be able to transfer heat. Thus, even when the cover lower member 61 is made of a material that is easily broken, the cover lower member 61 can be prevented from being broken by the collision of vibration with the first bus bar 20a and the second bus bar 22 a. The first bus bar 20a and the second bus bar 22a are connected to the first inner heat conductive sheet or the second inner heat conductive sheet 67 via the cover lower member so as to be able to transfer heat to the outer heat conductive sheet 65. Thereby, the battery case 40a is connected to the lower side of the cover lower member 61 via the first inner heat conductive sheet or the second inner heat conductive sheet 67. In this case, even when the cover lower member 61 is formed of a material that is easily broken, the cover lower member 61 can be prevented from being broken by the collision of vibration with the battery case 40 a. In this example, other configurations and operations are the same as those of fig. 1 to 3 or fig. 4.

In the structures of fig. 5 to 7, 1 inner-side heat conduction sheet may be used in common in place of the first inner-side heat conduction sheet 66 and the second inner-side heat conduction sheet 67. The heat transferred to first bus bar 20a and second bus bar 22a is transferred to case lower member 41a through a heat dissipation path including the inner heat conductive sheet.

Fig. 8 is a cross-sectional view showing a state where the outer heat conductive sheet 65 is peeled off from the device cover 60 in the relay unit 13 constituting the battery relay connection structure according to another example of the embodiment. In fig. 8, the first bus bar, the second bus bar, the first inner thermally conductive sheet, and the second inner thermally conductive sheet are not shown. In the same manner as the structure of fig. 6, the outer heat conductive sheet 65 is bonded to the lower surface of the cover lower member 61. In such a configuration, when the relay unit 13 is transported to a place where it is assembled in the battery case, an external object or person may unexpectedly come into contact with the outer heat conductive sheet 65 and apply a force to the outer heat conductive sheet 65. This may cause the outer heat conductive sheet 65 to peel off from the cover lower member 61. Further, when the moving member moves in a state where the relay unit 13 is disposed on the moving member (not shown), the device cover 60 of the relay unit 13 vibrates, and the outer heat conductive sheet 65 may slide with respect to the cover lower member 61 and may be positionally displaced.

Further, when foreign matter such as dust adheres to the surface of the outer heat conductive sheet 65, the heat conduction performance of the outer heat conductive sheet 65 may be degraded. In order to prevent the decrease of the thermal conductivity, it is conceivable to attach a surface film to the lower surface of the outer thermal conductive sheet 65. The surface film is removed prior to assembling the relay unit 13 to the battery case 40a (fig. 5). Therefore, it is necessary to facilitate the removal operation of the surface film.

Next, another example of the embodiment described with reference to fig. 9 and 10 is an example of the invention for improving such an aspect. Fig. 9 is a cross-sectional view showing a relay unit 13a constituting another example of the embodiment. Fig. 10 is a view seen in the direction of arrow a of fig. 9. In fig. 9, the first bus bar, the second bus bar, the first inner heat conductive sheet, and the second inner heat conductive sheet are not shown, as in fig. 8.

In the configuration of this example, the outer heat conductive sheet 65 is bonded to the lower surface of the cover lower member 61a constituting the device cover 60 a. Further, a sheet protection wall 70 protruding downward is formed on the lower surface of the cover lower member 61a at a portion facing at least a part of the outer peripheral surface of the outer heat conductive sheet 65. The sheet protection wall 70 is formed in a cylindrical shape having a substantially rectangular cross section so as to surround the outer heat conductive sheet 65. The sheet protection wall 70 has a height larger than the thickness of the outer thermally conductive sheet 65.

Further, in a portion of the sheet protection wall 70 in the circumferential direction and facing a side surface of a portion of the outer peripheral surface of the outer heat conductive sheet 65, a notch 71 is formed over the entire length of the sheet protection wall 70 in the height direction. Thus, the notches 71 are formed so as to partially expose in the circumferential direction on the outer circumferential surface including the lower end of the outer heat conductive sheet 65.

Further, a surface film (not shown) for preventing adhesion of foreign matters to the lower surface of the outer heat conductive sheet 65 is bonded to the lower surface of the relay unit 13a during conveyance. The surface film is removed before the relay unit 13a is assembled to the battery case.

According to the above configuration, the sheet protection wall 70 protruding downward is formed on the lower surface of the cover lower member 61a at a portion facing at least a part of the outer peripheral surface of the outer heat conductive sheet 65. Accordingly, it is possible to prevent the outer heat conductive sheet 65 from being peeled off from the cover lower member 61a by an external object or person coming into contact with the outer heat conductive sheet during the transmission of the relay unit 13 a.

The sheet protection wall 70 is formed in a cylindrical shape having a substantially rectangular cross section so as to surround the outer thermally conductive sheet 65 on the lower surface of the cover lower member 61a, and the height of the sheet protection wall 70 is larger than the thickness of the outer thermally conductive sheet 65. This can further prevent the outer heat conductive sheet 65 from peeling off from the cover lower member 61 a.

Further, in the sheet protection wall 70, a cutout 71 is formed so as to partially expose in the circumferential direction on the outer peripheral surface including the lower end of the outer heat conductive sheet 65. Thus, when the surface film is stuck to the lower surface of the outer thermally conductive sheet 65 during the transfer of the relay unit 13a, the surface film is easily detached from the outer thermally conductive sheet 65 through the notch 71 at the end of the transfer. The surface film is removed by an operator. For example, the worker can easily detach the top film from the outer heat conductive sheet 65 by sticking an adhesive tape to the lower surface of the top film through the slit 71. The worker can insert a finger into the sheet protection wall 70 through the slit 71, and can easily remove the top film from the outer heat conductive sheet 65 by hooking the finger to the adhesion side of the top film. The other configurations and functions are the same as those of fig. 1 to 3, fig. 4, or fig. 5 to 7.

Fig. 11 is a cross-sectional view showing a state in which the first bus bar 20a and the second bus bar 22a in the device cover 60b are connected to the case lower member 41b constituting the battery case 40b, in another example of the embodiment. Fig. 12 is an enlarged view of a portion B of fig. 11. Fig. 13 is a view of the relay unit 13b constituting the battery relay connection structure, partially omitted, as viewed from below, with the cover lower member 61b (fig. 12) of the equipment cover removed. Fig. 14 is a perspective view showing a part of the first bus bar 20a and the second bus bar 22a disposed on the cover lower member 61b in the relay unit 13 b.

In the structure of this example, as shown in fig. 11 and 12, the battery case 40b is formed by coupling the case upper member 45a and the case lower member 41b with bolts 72. An equipment cover 60b forming the relay unit 13b is fixed to the case lower member 41 b. The equipment cover 60b is formed by joining a cover upper member 62a and a cover lower member 61 b. The positive relay 14 is fixed to the cover upper member 62a inside the device cover 60 b.

As shown in fig. 13, the lengthwise intermediate portions of the first bus bar 20a and the second bus bar 22a are arranged below the positive electrode relay 14 (on the front side of the paper surface in fig. 13) and along the width direction of the relay case 16 (the vertical direction in fig. 13). A projection 21 that projects toward one side in the width direction of the relay case 16 (the lower side in fig. 13) is formed at a portion disposed below the relay case 16 in the longitudinal direction intermediate portion of the first bus bar 20 a. Fig. 11 and 12 correspond to the section C-C in fig. 13. The projection 21 and a portion of the second bus bar 22a located below the relay case 16 in the middle in the longitudinal direction are arranged in line in the longitudinal direction of the relay case 16 (the left-right direction in fig. 11, 12, and 13). The first bus bar 20a and the second bus bar 22a are disposed apart from each other. As shown in fig. 13, the other end portion (right end portion in fig. 13) of the first bus bar 20a is screwed to the cover upper member 62a together with an intermediate bus bar (not shown) on the other side (upper side in fig. 13) in the width direction of the relay case 16. The other end portion (lower end portion in fig. 13) of the second bus bar 22a is screwed to the cover upper-side member 62a on one side (lower side in fig. 13) in the width direction of the relay case 16, and is connected to the inverter-side connector terminal T5 (fig. 1).

As shown in fig. 12 and 14, a first recess 74 and a second recess 75 partitioned by an insulating wall 73 are formed in the upper surface of the cover lower member 61b constituting the device cover 60 b. The insulating wall 73 is a double wall and is formed by 2

wall portions

73a and 73 b.

Wall portions

73a and 73b have an L-shape when viewed from above, corresponding to L-shaped gap 80 between first bus bar 20a and second bus bar 22a shown in fig. 13, and are arranged with a gap therebetween. Thus, the insulating wall 73 is formed with a recess 73c at the middle portion in the width direction over the entire length.

As shown in fig. 12, the first inner thermally conductive sheet 66 is disposed at the lower end of the first recess 74. Further, a flat plate-like longitudinal intermediate portion located at the lower end of the first bus bar 20a is disposed in the first concave portion 74 so as to overlap on the upper side of the first inner thermally conductive sheet 66. Accordingly, the second inner heat conductive sheet 67 is disposed at the lower end of the second recess 75. Further, in the second concave portion 75, a flat plate-like longitudinal intermediate portion positioned at the lower end of the second bus bar 22a is disposed so as to overlap on the upper side of the second inner heat conductive sheet 67. As shown in fig. 13, the first inner heat conductive sheet 66 is L-shaped, and the second inner heat conductive sheet 67 is rectangular.

Further, on the lower side of the cover lower member 61b (fig. 12), 1 rectangular outer heat conductive sheet 65 is bonded by adhesion at a position overlapping each of the inner heat

conductive sheets

66 and 67 as shown in fig. 13 when viewed from one side in the vertical direction.

According to the above configuration, first inner heat conductive sheet 66 contacting first bus bar 20a on the lower side and second inner heat conductive sheet 67 contacting second bus bar 22a on the lower side are disposed separately from first recess 74 and second recess 75 partitioned by insulating wall 73. Thus, even when moisture enters the device cover 60b or water is condensed from water vapor in the device cover 60b and accumulates in the lower end portion of the device cover 60b, the short circuit of the first bus bar 20a and the second bus bar 22a outside the relay can be prevented. The other configurations and functions are the same as those of fig. 1 to 3, fig. 4, or fig. 5 to 7.

In the above examples, the case where the

first bus bars

20a and 20b are electrically connected to the output terminals of the battery module 12 and the

second bus bars

22a and 22b are electrically connected to the input terminals of the load has been described. On the other hand, the first bus bar may be electrically connected to an input terminal of the load and the second bus bar may be electrically connected to an output terminal of the battery. In the above-described examples, the case where at least one of the first bus bar and the second bus bar is connected to the case lower member 41 of the battery case 40 so as to be capable of heat transfer has been described. On the other hand, the one bus bar may be connected to the case upper member of the battery case so as to be capable of heat transfer. In this case, for example, the equipment cover has a structure in which a lower end is closed and an upper end has an opening, and the one bus bar is connected to the case upper member via a thermally conductive sheet in the equipment cover. In the configurations of fig. 5 to 14, the configuration in which the

relay units

13, 13a, and 13b include the outer heat conductive sheet 65 is described, but the relay units may be configured not to include the outer heat conductive sheet. For example, the outer heat conductive sheet may be provided on the relay unit side in the battery case.

Description of the reference numerals

10 vehicle-mounted battery relay connection structure (battery relay connection structure), 12 battery module, 13a, 13b relay unit, 14 positive relay, 15 negative relay, 16 relay case, 20a, 20b primary bus bar, 21 projection, 22a, 22b secondary bus bar, 30 equipment cover, 31 flange, 32 bolt, 33 nut, 34 ceiling, 35 projection, 35a bus bar holding claw, 36 heat conduction sheet, 37 heat conduction sheet, 38a cover lower side member, 39 second heat conduction sheet, 40a, 40b battery case, 41a, 41b case lower side member, 42 bottom plate, 43 outer peripheral wall portion, 45a case upper side member, 46 ceiling, 47 outer peripheral wall portion, 48 heat insulator, 49 heat conduction member, 50 inverter, 51 outer peripheral wall portion, 52 recess, 53, 60a, 60b equipment cover, 53, 61. 61a, 61b cover the lower member, 62a cover the upper member, 63 top plate, 65 outer heat conductive sheet, 66 first inner heat conductive sheet, 67 second inner heat conductive sheet, 70 protective wall, 71 notch, 72 bolt, 73 insulating wall, 73a, 73b wall, 73c recess, 74 first recess, 75 second recess, 80 gap.

Claims

1. A relay unit is accommodated in a battery case,

the relay unit includes:

a first bus bar;

a relay electrically connected to the first bus bar; and

an equipment cover covering the first bus bar and the relay,

the equipment cover is box-shaped with a closed upper end, and comprises an upper part with an opening formed at the lower end and a lower part combined with the upper part in a manner of closing the opening of the upper part,

the lower member is formed of a resin having a higher heat conductivity than the upper member,

the first bus bar is connected to the lower member so as to be capable of heat transfer via a first inner heat conductive sheet disposed between the first bus bar and the lower member,

the first inner thermally conductive sheet is an insulating resin sheet having a lower surface hardness than the lower member.

2. The relay unit according to claim 1,

the relay unit includes an outer heat conductive sheet disposed on a lower side of the lower member,

the first bus bar is connected to the outer heat conductive sheet through the first inner heat conductive sheet and the lower member so as to be capable of heat transfer.

3. The relay unit according to claim 2,

the relay unit is provided with a second bus bar covered by the device cover,

the relay is electrically connected between the first bus bar and the second bus bar, respectively,

a first concave portion and a second concave portion separated by an insulating wall are formed on the upper surface of the lower member,

the first inner thermally conductive sheet is disposed in the first recess, and the first bus bar is disposed in the first recess so as to overlap with the first inner thermally conductive sheet,

a second inner thermally conductive sheet is disposed in the second recess, and the second bus bar is disposed in the second recess so as to overlap the second inner thermally conductive sheet,

the first bus bar is connected to the outer heat conductive sheet so as to be capable of heat transfer via the first inner heat conductive sheet and the lower member, and the second bus bar is connected to the outer heat conductive sheet so as to be capable of heat transfer via the second inner heat conductive sheet and the lower member.

4. The relay unit according to claim 2,

the outer heat conductive sheet is bonded to the lower side surface of the lower side member,

a sheet protection wall protruding downward is formed on a lower surface of the lower member at a portion facing at least a part of an outer peripheral surface of the outer thermally conductive sheet.

5. The relay unit according to claim 4,

the outer heat conductive sheet has a rectangular shape as viewed from one side in the thickness direction,

the sheet protective wall is formed in a rectangular shape in cross section so as to surround the outer thermally conductive sheet,

the sheet protection wall has a height greater than a thickness of the outer thermally conductive sheet.

6. The relay unit according to claim 4,

in the sheet protection wall, a cutout is formed in an outer peripheral surface including a lower end of the outer heat conductive sheet so as to be partially exposed in a circumferential direction.