WO2018054453A1

WO2018054453A1 - An electrical junction box

Info

Publication number: WO2018054453A1
Application number: PCT/EP2016/072306
Authority: WO
Inventors: Ivar Alm
Original assignee: Volvo Truck Corporation
Priority date: 2016-09-20
Filing date: 2016-09-20
Publication date: 2018-03-29

Abstract

The invention relates to an electrical junction box (1) configured for connecting a plurality of connector elements (5a, 5b, 5c) forming part of a voltage bus in a vehicle, said junction box (1) comprising an electrically insulating enclosure (2) and at least one electrically conducting busbar component (11, 12), said enclosure (2) being provided with openings (4a, 4b, 4c) corresponding to said connector elements (5a, 5b, 5c) and adapted for insertion of said connector elements (5a, 5b, 5c) at least partly into said enclosure (2). Furthermore, the connector elements (5a, 5b, 5c) are configured for serving as a single support for said busbar component (11, 12). The invention also relates to a method for manufacturing an electrical junction box (1).

Description

An electrical junction box

TECHNICAL FIELD

The invention relates to an electrical junction box configured for connecting a plurality of connector elements forming part of a voltage bus in a vehicle, said junction box comprising an electrically insulating enclosure and at least one electrically conducting busbar component, said enclosure being provided with openings corresponding to said connector elements and adapted for insertion of said connector elements at least partly into said enclosure. The invention also relates to a method for manufacturing an electrical junction box for connecting a plurality of connector elements forming part of a voltage bus in a vehicle, said method comprising the following steps: providing an electrically insulating enclosure; mounting at least one electrically conducting busbar component in said enclosure; and providing openings in said enclosure and allowing insertion of said connector elements at least partly into said enclosure.

The invention can be applied in connection with electric equipment for heavy-duty vehicles, such as trucks, buses and construction equipment such as wheel loaders, and also other vehicles such as cars, working machines such as articulated haulers and excavators, and marine vessels. Consequently, the invention is not restricted to any particular type of vehicle.

BACKGROUND

In the field of vehicles, for example heavy trucks and other commercial transport vehicles, it is of high importance to provide adequate solutions for supply of electric power between various types of electrical equipment. In particular, electrical equipment related to rechargeable battery packs, power sources such as electric traction motors, external battery charging systems and similar devices must be electrically connected in a reliable and secure manner.

The above-mentioned type of equipment is relevant with regard to vehicles such as for example hybrid vehicles, plug-in hybrid vehicles and full electric vehicles. Also, conventional vehicles provided with combustion engines are also equipped with electrical equipment which must be installed and connected in a correct manner.

In order to provide the above-mentioned electrical functions, it is previously known to use an electrical junction box in order to connect different types of electrical equipment. The electrical conductors, switches and couplings which are used in such a junction box may be arranged for supplying a voltage of the magnitude of 600 V or more, and conducting a current of the magnitude 100 ampere or more. However, a junction box is normally not limited to any particular voltage or current range, but can be used in various electrical environments requiring different levels of voltage and current.

In a junction box, it is common to connect various conductors via so-called busbar components, i.e. electrically conducting elements which are mounted inside the junction box. Furthermore, electrical wires with connector elements are normally guided into the junction box so that they may be fastened to a busbar. A cover is also used for closing the box.

According to known technology, there may be a number of electric components such as cables, connector elements, busbars, fastening elements and other components within the enclosure of the junction box. For this reason, such a known junction box may be space-demanding and may also be associated with a high cost and high degree of complexity, which is a disadvantage.

Furthermore, the large number of components in known junction boxes may cause high resistive losses, which in turn may generate unwanted generation of heat.

The patent document US 9197048 discloses a high-voltage electrical junction box which comprises an insulating box body, an insulating board which is arranged inside the box body and also a busbar which is disposed on one surface of the board. The junction box is arranged for high-voltage electrical equipment in a high-voltage vehicle in order to connect a power supply such as a battery to a drive source.

A problem with the solution according to US 9197048 is that it is relatively space- demanding and that it comprises relatively many components, which makes it complex and costly. Due to the high number of components, it will also have a relatively high weight.

SUMMARY

An object of the invention is consequently to provide an electrical junction box by means of which the above-mentioned drawbacks can be overcome, i.e. for providing a junction box which is compact and light and which decreases the demands for space and the weight of the entire vehicle. Also, it is an object to provide junction box having few components. This means that it may be easy to manufacture and may allow a simplified assembly process in connection with manufacturing of a vehicle. This will also reduce the cost of the junction box and the entire vehicle.

The object is achieved by an electrical junction box configured for connecting a plurality of connector elements forming part of a voltage bus in a vehicle, said junction box comprising an electrically insulating enclosure and at least one electrically conducting busbar component, said enclosure being provided with openings corresponding to said connector elements and adapted for insertion of said connector elements at least partly into said enclosure. The connector elements are configured for serving as a single support for said busbar component.

By the provision of an electrical junction box as specified above, certain advantages are obtained. Firstly, there is provided a junction box which requires very little space and which has a low weight, which is an advantage in the field of vehicles. Furthermore, the junction box can be very easily manufactured with a relatively low number of components which reduces cost. An additional advantage is that the junction box can be designed in a manner so that the electrical resistance between different connections is kept very low, which leads to low electrical losses and a low amount of generated heat.

The invention is for example useful in the field of electrical vehicles or hybrid electric vehicles, in which a rechargeable battery pack is used as a power source for an electric traction motor and in which the junction box is configured for a relevant traction voltage in the vehicle in question. According to an embodiment, each connector element comprises an end section which is configured for electrically connecting the connector element to said busbar component. This contributes to a simple manufacturing process. According to an embodiment, the connector element comprises at least a coupling extending out of said enclosure and being arranged to be connected to an electrically conductive element forming part of said voltage bus. In this manner, external conductive wires can be connected in an effective manner. Furthermore, according to an embodiment, each end section has a threaded section cooperating with a locking nut, for attaching said connector element to said busbar component. This contributes also to the simple manufacturing process while creating a secure fixing arrangement for the busbar component. The above-mentioned object is also achieved by a method for assembly of an electrical junction box for connecting a plurality of connector elements forming part of a voltage bus in a vehicle. The method comprises the following steps: providing an electrically insulating enclosure; mounting at least one electrically conducting busbar component in said enclosure; and providing openings in said enclosure and allowing insertion of said connector elements at least partly into said enclosure. The method further comprises configuring said connector elements so as to serve as a single support for said busbar component.

Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, below follows a more detailed description of embodiments of the invention cited as examples.

Fig. 1 is an exploded view of an embodiment of the invention, as regarded from a rear view; Fig. 2 is a perspective view as seen from a rear view, of an enclosure forming part of a junction box according to an embodiment of the invention;

Fig. 3 is a perspective view according to a front view of a partly assembled

junction box; and

Fig. 4 is a perspective view from the same direction as Fig. 3 but showing the junction box in a fully assembled condition. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Different aspects of the present disclosure will be described more fully hereinafter with reference to the enclosed drawings. The method and system disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein.

The invention will now be described with reference to an embodiment and the enclosed drawings. With initial reference to Fig. 1 , there is shown an exploded view of an electrical junction box 1 according to an embodiment of the invention. The junction box 1 comprises a main part in the form of an enclosure 2 which is shaped generally as a rectangular container with a rear wall 3 having a first opening 4a, a second opening 4b and a third opening 4c. The purpose of these three openings 4a, 4b, 4c is to receive a first connector element 5a, a second connector element 5b and a third connector element 5c, respectively, and to allow fastening of these connector elements 5a, 5b, 5c on said rear wall 3.

Each one of the three connector elements 5a, 5b, 5c is designed with a first coupling 6a and a second coupling 6b, as indicated in Fig. 1 for the first connector element 5a. Similar couplings are consequently provided for the second connector element 5b and the third connector element 5c.

Also, as shown in Fig. 1 , the first coupling 6a is connected to a first electrical conductor 7a such as a conductive wire, whereas the second coupling 6b is connected to a second electrical conductor 7b such as a further conductive wire. Each one of the first and second electrical conductors 7a, 7b is configured so as to be connected to an electrical component such as a battery pack, an electric drive motor, a conductor for a charging arrangement (for charging a battery pack), a power inverter or a similar device which suitably are used in a vehicle (not shown in the drawings). More precisely, the junction box 1 designed to be used when a certain traction voltage is applied in order to operate the vehicle and relevant electrical components. Such electrical components are previously known as such and are not shown in the drawings.

Furthermore, similar arrangements of electrical conductors are also provided in

connection with the second connector element 5b and the third connector element 5c.

Each one of the connector elements 5a, 5b, 5c is configured so as to be mounted in a corresponding opening 4a, 4b, 4c of the enclosure 2. Also, each connector element 5a, 5b, 5c has two conductive end sections 8 which are arranged to extend into the interior of the enclosure 2 (of which only four end sections 8 are visible in Fig. 1 ). The end sections 8 of the first connector element 5a are electrically connected to the first conductive wire 7a and the second conductive wire 7b, respectively, and similar arrangements are provided for the second connector element 5b and the third connector element 5c.

There are three connector elements 5a, 5b, 5c shown in Fig. 1 and each connector element has two conductive end sections 8, meaning that there are in total six end sections 8 in the junction box assembly 1 shown in Fig. 1 . However, only four of these end sections 8 are shown in Fig. 1 .

In order to mount the three connector elements 5a, 5b, 5c in the corresponding openings 4a, 4b, 4c of the rear wall 3, there is provided a plurality of screws 9. Furthermore, each connector element 5a, 5b, 5c is formed with a flange-like part through which four screws 9 are inserted and then fastened in a corresponding threaded hole 10 in the rear wall 3 of the enclosure 1 . Fig. 1 shows the manner in which the connector elements 5a, 5b, 5c can be securely mounted in the rear wall 3 of the enclosure 1 by means of these screws 9.

With reference to Fig. 2, there is shown a rear view of the enclosure 2 with the three connector elements 5a, 5b, 5c being screwed into their fastened condition. In this position, the connector elements 5a, 5b, 5c are securely mounted so that their end sections (not visible in Fig. 2) protrude into the interior of the enclosure 2. Furthermore, and now referring to Fig. 3, the enclosure 2 is shown in a view as opposed to the direction of Fig. 2, i.e. as seen towards the interior of the enclosure 2. In particular, Fig. 3 shows the way the three connector elements 5a, 5b, 5c are mounted in a manner so that each one of the end sections 8 extends into the interior of the enclosure 2. As 5 seen in Fig. 3, the end sections 8 are arranged in the form of two straight lines or rows.

Referring now to Fig. 4, there is shown a view similar to Fig. 3 but in which a first busbar component 1 1 and a second busbar component 12 are attached to each row as defined by the end sections 8. In order to accomplish this, each one of the busbar components 1 1 , 10 12 is provided with holes which correspond to the positions and dimensions of the end sections 8. After positioning the busbar components 1 1 , 12 so that the end sections 8 extend through the holes of the busbar components 1 1 , 12, a nut 13 is fastened onto each end section 8 in a manner so as to secure the busbar components 1 1 , 12 to all of the connector elements 5a, 5b, 5c.

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The manner in which the busbar components 1 1 , 12 are locked to the connector elements 5a, 5b, 5c is also shown in Fig. 1 , which shows an exploded view including the busbar components 1 1 , 12 and the nuts 13 in a position before mounting these components. As mentioned above, the threaded end of each end section 8 is locked by means of a

20 corresponding nut 13 so that the busbar components 1 1 , 12 are securely held in place. In particular, it should be noted that the busbar components 1 1 , 12 are fastened in the enclosure 2 using only the connector elements 5a, 5b, 5c as support, i.e. as fastening points.

25 Finally, the enclosure 2 of the junction box 1 is sealed by means of a cover 14, which is fastened along the edges of the enclosure 2 by means of a number of screws 15.

Regarding suitable materials to be used for the junction box 1 , it should be noted that according to an embodiment, the enclosure 2 and the cover 14 are manufactured from

30 aluminium, which is a material which provides efficient electromagnetic shielding of the junction box 1 and which also has a low weight and is easy to manufacture. Aluminium is also resistant to high temperatures. Alternatively, the enclosure 2 and the cover 14 can be manufactured from a suitable plastics material. In such case, the inside of the enclosure 2 and the cover 14 is then suitably covered with a conductive layer, such as a thin metallic

35 film, which is configured so as to provide electromagnetic shielding. The busbar components are suitably manufactured from a highly conductive material such as copper, although other metals and alloys also are possible. Furthermore, the number of connector elements - and the corresponding number of openings in the rear wall of the enclosure 2 - may vary so as to adapt the junction box 1 to a particular electrical environment in which it is to be used. Also, the configuration of the connector elements may be designed in various ways, i.e. with a number of end elements along two rows (as shown in Figs. 1 -4) or in three or more rows, or in a single row, or in any suitable configuration as long as it is adapted to the design and dimensions of the busbar components.

Furthermore, according to the embodiment of Figs. 1 -4, two couplings 6a, 6b (and two corresponding end sections 8) are provided on each connector element 5a, 5b, 5c.

However, according to further embodiments, the couplings may assume other

configurations depending on the specifications and requirements of the electrical environment in which the junction box 1 is used.

In summary, the invention has an advantage since it allows a very simple assembly process for manufacturing an electrical junction box 1 . Firstly, the enclosure 2 is provided in the form of a generally rectangular container with the openings 4a, 4b, 4c in which the connector elements 5a, 5b, 5c are mounted. Subsequently, the busbar components 1 1 , 12 are mounted using only the connector elements 5a, 5b, 5c and their end elements 8 as support. This means that the busbar components 1 1 do not need any separate fastening components, which othwerwise would have added to the cost, weight, volume and complexity of the complete junction box 1 .

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

For example, the junction box 1 can be provided with additional electrical equipment such as for example a high voltage interlock loop (HVIL) circuit, which is a device commonly used in a junction box in order to protect against unintended access to electrical components. More precisely, a HVIL circuit is arranged to disconnect a power supply in case any potentially dangerous electrical condition should arise.

Furthermore, the openings mentioned above for fastening the connector elements could in principle also be arranged in the cover or side walls of the enclosure.

Also, other types of fastening elements for the connector elements 5a, 5b, 5c than the above-mentioned screws 9 (with associated threaded holes) can be used.

Claims

1 . An electrical junction box (1 ) configured for connecting a plurality of connector elements (5a, 5b, 5c) forming part of a voltage bus in a vehicle, said junction box (1 ) comprising an electrically insulating enclosure (2) and at least one electrically conducting busbar component (1 1 , 12), said enclosure (2) being provided with openings (4a, 4b, 4c) corresponding to said connector elements (5a, 5b, 5c) and adapted for insertion of said connector elements (5a, 5b, 5c) at least partly into said enclosure (2); characterized in that said connector elements (5a, 5b, 5c) are configured for serving as a single support for said busbar component (1 1 , 12).

2. An electrical junction box (1 ) according to claim 1 , wherein each connector element (5a, 5b, 5c) comprises an end section (8) which is configured for electrically connecting said connector element (5a, 5b, 5c) to said busbar component (1 1 , 12).

3. An electrical junction box (1 ) according to claim 1 or 2, wherein said connector element (5a, 5b, 5c) comprises at least a coupling (6a, 6b) extending out of said enclosure (2) and being arranged to be connected to an electrically conductive element (7a, 7b) forming part of said voltage bus.

4. An electrical junction box (1 ) according to claim 3, wherein said electrically conductive element (7a, 7b) is an electrical wire.

5. An electrical junction box (1 ) according to any one of claims 2-4, wherein each end section (8) has a threaded section cooperating with a locking nut (13), for attaching said connector element (5a, 5b, 5c) to said busbar component (1 1 , 12).

6. An electrical junction box (1 ) according to any one of the preceding claims, wherein said busbar component (1 1 , 12) is configured with a weight and with dimensions adapted so as to allow said connector elements (5a, 5b, 5c) to serve as said single support.

7. An electrical junction box (1 ) according to any of the preceding claims, wherein the electrical junction box (1 ) comprises a cover (14) arranged for fastening to said enclosure (2).

8. An electrical junction box (1 ) according to any of the preceding claims, wherein said junction box (1 ) is configured so as to be connected to a power supply associated with a drive source in said vehicle.

5 9. A vehicle of the hybrid or full electric type, comprising an electrical junction box (1 ) according to any one of claims 1 -8.

10. Method for assembly of an electrical junction box (1 ) for connecting a plurality of connector elements (5a, 5b, 5c) forming part of a voltage bus in a vehicle, said method 10 comprising the following steps:

- providing an electrically insulating enclosure (2);

- mounting at least one electrically conducting busbar component (1 1 , 12) in said enclosure (2); and

- providing openings (4a, 4b, 4c) in said enclosure (2) to allow insertion of said connector 15 elements (5a, 5b, 5c) at least partly into said enclosure (2);

characterized in that said method further comprises:

- configuring said connector elements (5a, 5b, 5c) so as to serve as a single support for said busbar component (1 1 , 12).

20 1 1 . Method according to claim 10, further comprising:

- electrically connecting an end section (8) of said connector element (5a, 5b, 5c) to said busbar component (1 1 , 12).

12. Method according to claim 1 1 , further comprising:

25 - attaching said connector element (5a, 5b, 5c) to said busbar component (1 1 , 12) by means of a locking nut (13) cooperating with a threaded section of said end section (8).

13. Method according to any one of claims 10-12, further comprising:

- connecting a coupling (6a, 6b) forming part of said connector element (5a, 5b, 5c) to an 30 electrically conductive element (7a, 7b) forming part of said voltage bus.

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