Electrical connection box for a storage battery, storage battery and motor vehicle

Abstract

The invention relates to an electrical connection box for a storage battery (2), comprising: - a platform (4) suitable for receiving electrical components (5, 6, 7), in which platform at least one circulation line (18) for a heat-transfer fluid is provided; - a busbar (8, 9, 10, 11) providing an electrical connection between at least two electrical components; and - at least one heat pipe (14), a first portion (20) of which has a first area of contact with the platform and a second portion (21) of which has a second area of contact with the busbar and / or with at least one of the electrical components. The invention also relates to a storage battery provided with such a box and to a motor vehicle provided with such a battery.

Description

DESCRIPTION TITLE OF THE INVENTION: ELECTRICAL CONNECTION BOX FOR STORAGE BATTERY, STORAGE BATTERY AND MOTOR VEHICLE TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates generally to the cooling of electrical devices.

[0002] It relates more particularly to an electrical connection box for a storage battery, a storage battery equipped with such a box and a motor vehicle equipped with such a storage battery. STATE OF THE ART

[0003] Electric or hybrid vehicles are equipped with a storage battery comprising a casing that houses several electrochemical cells connected together and providing a high voltage to the battery terminals, typically a voltage of several hundred volts.

[0004] It is then necessary to equip the battery with an electrical connection box containing electrical safety components (relays, fuses) in order to cut off the current if necessary. These components are positioned along a bus bar ("busbar", according to the Anglo-Saxon term) in which the input or output current of the battery circulates.

[0005] In certain situations, the battery provides or receives high electrical power. This is the case, for example, during so-called rapid charging of the vehicle battery, or when the vehicle must provide significant tractive effort. In these situations, the flow of high current generates a sharp increase in battery temperature, particularly at the battery terminals and bus bars.

[0006] Certain areas of the enclosure are likely to experience particularly high temperature increases; these areas are traditionally referred to as "hot spots". The enclosure components located at the hot spots are at increased risk of damage. In order to protect these components, there are systems for cooling the enclosure as a whole. Given the large volume of the enclosure, these solutions are not very effective and generate significant bulk and a excessive increase in the weight of the case. PRESENTATION OF THE INVENTION

[0007] In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes to locally cool the housing at the hot spots.

[0008] According to one aspect, there is provided an electrical connection box for a storage battery, comprising: - a platform suitable for accommodating electrical components and in which at least one heat transfer fluid circulation pipe is provided, - a bus bar providing an electrical connection between at least two electrical components, and - at least one heat pipe, a first portion of which has a first contact zone with the platform and a second portion of which has a second contact zone with the bus bar and / or with at least one of the electrical components.

[0009] The heat pipe(s) allow the areas to be cooled to be targeted on the bus bar or on the components, which advantageously allows for efficient cooling of the housing. In addition, the use of a heat pipe eliminates the need for a heat transfer fluid circulation circuit at the electrical components or the bus bar. The weight and size of the housing cooling elements are therefore advantageously limited.

[0010] Other advantageous and non-limiting characteristics of the electrical connection box according to the invention, taken individually or in all technically possible combinations, are the following: - the first contact zone has a surface area at least equal to the surface area of ​​the second contact zone, and preferably at least three times greater than the surface area of ​​the second contact zone. - the first portion is covered with an electrically insulating coating and / or the second portion is covered with an electrically insulating coating. - the circulation line is configured to be connected to a circuit for circulating a heat transfer fluid which comprises at least one pump. - a gallery adjoining the circulation pipe is provided in the platform and the heat pipe is fixed to the platform by means of a screw configured for fit into a tapped hole made in the platform and opening into the gallery. - a support plate is fixed on the platform and is configured to receive the electrical components. - the support plate is fixed to the platform by means of a stud welded to the platform and configured to fit into a corresponding hole in the support plate. - the support plate is made of acrylonitrile butadiene styrene. - a first face of the electrical component is in contact with the platform, the housing comprising a distal plate which is in contact with a second face of the electrical module, which is fixed to the support plate and which is configured to hold the electrical component against the platform by clamping. - the second portion of the heat pipe has the second contact zone with the bus bar, the contact between the heat pipe and the bus bar being ensured by two flanges fixed to each other and between which the second portion and the bus bar are held against each other.

[0011] The invention also provides a storage battery for a motor vehicle, comprising electrochemical cells and at least one electrical connection box according to the invention.

[0012] The invention also provides a motor vehicle comprising a storage battery according to the invention.

[0013] Of course, the various features, variants and embodiments of the invention may be combined with each other in various combinations to the extent that they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0014] The description which follows with reference to the appended drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

[0015] On the attached drawings:

[0016] [Fig. 1] is a schematic view of a motor vehicle according to the invention, provided with an accumulator battery equipped with an electrical connection box;

[0017] [Fig. 2] is a detailed schematic view of the electrical connection box of Fig. 1;

[0018] [Fig. 3] schematically represents a platform of the connection box of Figure 2;

[0019] [Fig. 4] schematically represents a heat pipe of the electrical connection box of Figure 2;

[0020] [Fig. 5] schematically represents a horizontal fixing flange of the heat pipe of Figure 4;

[0021] [Fig. 6] schematically represents a vertical fixing flange of the heat pipe of Figure 4;

[0022] [Fig. 7] schematically illustrates the fixing of the heat pipe of Figure 4 on the platform of Figure 3 by the horizontal flange of Figure 5;

[0023] [Fig. 8] schematically illustrates the fixing of the heat pipe of Figure 4 on the platform of Figure 3 by the vertical flange of Figure 6;

[0024] An electrical connection box according to one embodiment of the invention, as shown in Figure 1 and designated as a whole by the reference numeral 1, is used for connecting a storage battery 2 to the electrical network 3 of an electric or hybrid motor vehicle V. It thus equips the storage battery 2 and is connected to one of its two electrical terminals. For example, two identical electrical connection boxes are respectively connected to the two electrical terminals of the storage battery 2.

[0025] As illustrated in Figure 2, the electrical connection box 1 comprises - a platform 4 which accommodates electronic components 5, 6, 7, - a bus bar 8, 9, 10, 11 configured to provide an electrical connection between the electrical components 5, 6, 7, a connection terminal 12 to the storage battery 2 and a connection terminal 13 to the electrical network 3 of the motor vehicle V.

[0026] The platform 4 generally has a parallelepiped shape, with two main upper and lower faces. This platform 4 is here a wall of a housing of the accumulator battery 2 of the vehicle V and can be installed horizontally on the vehicle, so that its upper face itself extends horizontally. In the remainder of this presentation, it is in this particular orientation that the electrical connection box 1 will be described.

[0027] The electrical components 5, 6, 7 and the bus bar 8, 9, 10, 11 are here fixed to a receiving face F of the platform 4, here the upper face, by means of a support plate 15. Here, the support plate 15 is fixed to the receiving face F of the platform 4 by means of studs 16 welded on the platform 4 and configured to be inserted into corresponding holes of the support plate 15 and to receive bolts locking the support plate. The electrical components 4, 5, 6 and the bus bar 8, 9, 10, 11 are here fixed to the support plate 15 by fixing screws 17. The support plate 15 is for example made of a polymer material, preferably acrylonitrile butadiene styrene (ABS).

[0028] The bus bar 8, 9, 10, 11 is configured to be crossed by a high intensity current, for example a current greater than or equal to 500 Amperes. In this example, the bus bar 8, 9, 10, 11 comprises a plurality of distinct portions, here four distinct portions, each portion providing an electrical connection between two electrical components (here, portions 9 and 10), between an electrical component and the terminal 12 for connection to the storage battery (portion 8) or between an electrical component and the terminal 13 for connection to the electrical network of the motor vehicle V (portion 11).

[0029] The electrical components 5, 6, 7 are here configured to cut the electrical connection between the storage battery 2 and the electrical network 3 of the motor vehicle (here between terminal 12 and terminal 13). For example, the components comprise an electromechanical relay 5, a switch 6 and a fuse 7.

[0030] The electromechanical relay 5 is configured to, during normal use of the vehicle, reversibly cut the connection between the storage battery 2 and the electrical network 3, for example after the vehicle V has been parked. It is, for example, controlled by a driver of the motor vehicle.

[0031] The switch 6 is here a pyrotechnic safety switch (“pyroswitch”, according to the Anglo-Saxon term) and is configured to cut the electrical connection in the event of an accident of the motor vehicle V. It is for example controlled by a sensor of the motor vehicle, for example an impact sensor.

[0032] Fuse 7 is configured to cut the electrical connection when it is crossed by a current of too high intensity, which would be caused for example by a short circuit.

[0033] When using the motor vehicle V, for example when rapidly charging the storage battery 2 or when the vehicle is driven by an electric motor powered by the storage battery, the temperature of the bus bar 8, 9, 10, 11 can increase significantly and generate hot spots, in particular at the fixing screws 17.

[0034] The configuration of the housing 1 according to the invention advantageously allows the heat generated at the bus bar 8, 9, 10, 11 to be evacuated and therefore the corresponding hot spots to be neutralized. To this end, the housing 1 comprises at least one heat pipe 14 configured to evacuate at least part of the heat from the bus bar 8, 9, 10, 11 to the platform 4. So that the heat does not accumulate in the platform 4, at least one circulation pipe 18 for a heat transfer fluid is provided therein.

[0035] For the purposes of the invention, a "heat pipe" is understood to be a tubular sealed enclosure containing a fluid in a liquid-vapor equilibrium state, a first end of which is configured to be placed against a heat source and a second end of which is configured to be placed on a cold element or a heat sink. The fluid is configured to vaporize by absorbing thermal energy emitted by the heat source, circulate in the heat pipe to the second end and condense there to return to the liquid state.

[0036] Here, as illustrated in more detail in Figure 3, the platform 4 has a profiled structure, for example obtained by extrusion. It therefore comprises a plurality of pipes 18 and galleries 19 extending longitudinally from one end of the platform to the other. The terms pipe and gallery here designate the same type of entities, except that the pipes 18 are configured to be connected to a circuit for circulating a heat transfer fluid (for example, a glycol fluid). Such a circulation circuit (not shown and which is not itself the subject of the present invention) generally comprises a pump for forcing the circulation of the heat transfer fluid through the pipes 18, and a heat exchanger for cooling this fluid.

[0037] Here, the pipes 18 have circular sections. Connection fittings R for connection to the heat transfer fluid circulation circuit are then screwed into the ends of the pipes 18. The galleries 19, here of generally rectangular sections, also extend into the platform 4 so that each gallery 19 adjoins at least one circulation pipe 18. Tapped holes 32 opening into the galleries 19 are provided in the reception face F of the platform 4.

[0038] In this example, the housing 1 comprises five identical heat pipes 14, each being in contact with both a portion of the bus bar 8, 9, 10, 11 and with the platform 4. Here two heat pipes are in contact with a portion 10 of the bus bar which provides the electrical connection between the electromechanical relay 5 and the fuse 7, and a separate heat pipe is in contact with each of the other portions 8, 9, 11 of the bus bar. In practice, the number of heat pipes used per section of bus bar depends on the amount of heat to be removed.

[0039] Figure 4 illustrates a heat pipe 14 isolated from the rest of the housing 1. The heat pipe 14 here has a general L shape. It thus comprises a first rectilinear portion 20 configured to establish a contact zone with the platform 4 and a second rectilinear portion 21 orthogonal to the first rectilinear portion 20 and configured to establish a second contact zone with the bus bar 8, 9, 10, 11. The first rectilinear portion 21 and the second rectilinear portion 22 are connected by a curved intermediate portion 22.

[0040] The heat pipe 14 has flat surfaces at the contact zones. More specifically, the heat pipe 14 is here a flat heat pipe, with a generally rectangular cross-section, and of the capillary type, that is to say that its internal wall is lined with a capillary network, here a sintered type capillary network.

[0041] The second rectilinear portion 21 of the heat pipe 14, which establishes the second contact zone with the bus bar 8, 9, 10, 11, is covered with an electrically insulating coating, here a polyimide film, in particular Kapton®.

[0042] The fixing of the heat pipe 14 is here ensured by a system of fixing flanges 23, 24 comprising a horizontal fixing flange 23 (figure 5) ensuring the fixing of the heat pipe against the platform and a vertical fixing flange 24 (figure 6) ensuring the fixing of the heat pipe 14 against the bus bar.

[0043] The fixing flanges 23, 24 extend lengthwise along the axis of the rectilinear portion 20, 21 of the heat pipe which they block. They both have a U-shaped cross-section, defined by a main base 25 from which two lateral branches 26 extend orthogonally, so as to define a housing 27. The two fixing flanges 23, 24 having similar profiles, the same references will be used to designate the bases main branches 25 and the lateral branches 26 of the two flanges 23, 24.

[0044] The internal faces of the fixing flanges are covered, at the level of the lateral branches 26, with two protective strips 28, here two polymer strips (for example, TABS) which are glued against the lateral branches 26 and which extend over the entire length of these lateral branches 26.

[0045] The horizontal fixing flange 23 illustrated in Figure 5 has through holes 29, here six smooth holes, arranged vertically through the lateral branches, orthogonal to the main base 25.

[0046] The vertical fixing flange 24 illustrated in Figure 6 also has through holes 31, here four tapped holes, arranged horizontally through the lateral branches, orthogonal to the main base 25.

[0047] The end faces of the branches of the horizontal fixing flange 23 are here flat to be applied to the receiving face of the platform 4.

[0048] On the other hand, the end faces of the branches of the vertical fixing flange 24 each have a notch forming a recess 30. This recess is configured to receive in an adjusted manner (without play or with a small play) the bus bar 8, 9, 10, 11, as will be seen below.

[0049] In the vertical flange 24, the main base 25 has a notch on the side of its lower end, so as to allow the passage of the curved intermediate portion of the heat pipe 14, as will be seen below.

[0050] Figures 7 and 8 are exploded views which illustrate the fixing of the heat pipe by the fixing flanges 23, 24 at the level of the receiving face F of the platform 4.

[0051] As illustrated in Figure 7, the heat pipe 14 is placed against the receiving face F of the platform 4 so that its first rectilinear portion 20 establishes the first contact zone with the platform 4 and so that its second rectilinear portion 21 extends orthogonally to the receiving surface F.

[0052] The horizontal flange 23 is placed against the receiving surface F so that the first rectilinear portion 20 of the heat pipe 14 is located in the housing 27 and so that each through hole 29 made in the lateral portions 26 is opposite a corresponding tapped hole 32 opening into one of the galleries 19. Fixing screws 33 are inserted through the through holes 29 and screwed into the tapped holes 32, so that the lateral branches 26 of the horizontal flange 23 are kept in contact with the platform 4 and so that the main base 25 is kept in contact with the first rectilinear portion 20 of heat pipe 14.

[0053] Here, the contacts between the lateral branches 26 and the receiving face F, between the first rectilinear portion 20 of the heat pipe 14 and the main base 25 of the horizontal fixing flange 23 and between the first rectilinear portion 20 and the receiving face F are made by means of a thermal interface material 34 (typically thermal paste).

[0054] As illustrated in Figure 8, the heat pipe 14 is arranged so that its second straight portion 21 is in contact with the bus bar (for example here the portion 8 of the bus bar).

[0055] The vertical flange 24 is placed so that the second rectilinear portion 21 of the heat pipe 14 is located in the housing 27, in contact with the main base 25, and so that the portion 8 of the bus bar is placed in the recess 30 in an adjusted manner and in such a way that a first of its faces establishes a contact surface with the lateral branches 26.

[0056] A closing flange 35, here a rectangular plate having through holes 36, is placed in contact with a second face of the bus bar 8 opposite the first face so that each through hole 36 is placed opposite a tapped hole 31 of the vertical flange 24. Fixing screws 37 are inserted through the through holes 36 and screwed into the tapped holes 31 so that the second rectilinear portion 21 of the heat pipe 14 is held in contact with the first face of the portion 8 of the bus bar, so that the closing flange 35 is held in contact with the second face of the portion 8 of the bus bar and in contact with the vertical flange 24.

[0057] Here, the contacts between the second rectilinear portion 21 of the heat pipe 14 and the main base 25 of the vertical fixing flange 24, between the second rectilinear portion 21 and the portion 8 of the bus bar, and between the portion 8 and the closing flange 35 are made by means of the thermal interface material 34.

[0058] In this example, the dimensions of the heat pipe 14 are chosen so that the contact area between the first portion 20 and the receiving face F has a surface area three times greater than the surface area of ​​the contact area between the second portion 21 and the bus bar 8. The heat exchanges inside the heat pipe 14 being lower at the level of the second portion 21 (the hottest portion), such a ratio between the surfaces advantageously makes it possible to lower the heat flux density.

[0059] In order to further improve the thermal management of the housing 1, in particular the evacuation of the heat generated by the internal winding of the relay (which, for information purposes, may require a dissipation of 5 Watts), a first face of the electromechanical relay 5 is placed in contact with the receiving face F, here via the thermal interface material 34. A distal plate 38 is placed in contact with a second face of the thermal interface relay 5 opposite the first face, and is screwed to the support plate 15 so as to hold the thermal interface relay 5 against the receiving face F by tightening.

[0060] In order to ensure good heat dissipation from the hot spots, the materials of the platform 4 and the flanges 23, 24, 34 have a high thermal conductivity, for example greater than 100 W.rrr 1 .K' 1 For example, these elements are made of aluminum or aluminum alloy.

[0061] The embodiments described previously in connection with figures 1 to 9 are in no way limiting.

[0062] In particular, an electrical connection box has been described comprising five heat pipes. The invention is not limited by this number, and the box according to the invention may comprise any number of heat pipes, in particular a single heat pipe, and also any number of heat pipes per portion of bus bar, for example, one, two or three heat pipes.

[0063] In embodiments in which at least a portion of the bus bar is coupled to several heat pipes, these heat pipes can be fixed by the same set of clamps. For example, as seen in FIG. 1, two heat pipes 14 are held against the portion 10 of the bus bar by the same set 39 of clamps. Their straight portions are then placed in the same housing of the corresponding clamp and mutually separated by protective strips. Several heat pipes in contact with the same portion of the bus bar can also each be fixed by a separate set of clamps.

[0064] Several heat transfer fluid circulation pipes and several galleries produced by extrusion of the platform have been described previously. The housing according to the invention is not limited to this configuration, and the pipes and / or galleries may be produced by any other means, for example by drilling or by molding the platform. Furthermore, the housing according to the invention may comprise any number of heat transfer fluid circulation pipes, for example a single conduit, and any number of galleries or no galleries. In the latter case, the tapped holes provided at the level of the receiving face of the platform and allowing the fixing flanges to be screwed completely through the platform or are blind holes.

[0065] A housing comprising a support plate has been previously described. The invention is not limited to the presence of a support plate, and in certain embodiments, the components are directly attached to the platform.

Claims

CLAIMS

1. Electrical connection box for accumulator battery (2), comprising: - a platform (4) adapted to accommodate electrical components (5, 6, 7) and in which at least one circulation pipe (18) for a heat transfer fluid is provided, - a bus bar (8, 9, 10, 11) providing an electrical connection between at least two electrical components (9, 10), and - at least one heat pipe (14) of which a first portion (20) has a first contact zone with the platform (4) and of which a second portion (21) has a second contact zone with the bus bar (8, 9, 10, 11) and / or with at least one of the electrical components (5, 6, 7).

2. Housing according to claim 1, in which the first contact zone has a surface area at least equal to the surface area of the second contact zone.

3. A housing according to claim 1 or 2, wherein the second portion (21) is covered with an electrically insulating coating.

4. Housing according to any one of claims 1 to 3, in which the circulation pipe (18) is configured to be connected to a circuit for circulating a heat transfer fluid which comprises at least one pump.

5. Housing according to any one of claims 1 to 5, in which a gallery (19) adjoining the circulation pipe (18) is provided in the platform (4) and in which the heat pipe (14) is fixed to the platform (4) by means of a screw (33) configured to fit into a tapped hole (32) provided in the platform and opening into the gallery (19).

6. Housing according to any one of claims 1 to 5, wherein a support plate (15) is fixed on the platform (4) and is configured to receive the electrical components (5, 6, 7).

7. A housing according to claim 6, wherein the support plate (15) is fixed to the platform (4) by means of a stud (16) welded to the platform (4) and configured to fit into a corresponding hole in the support plate (15).

8. Housing according to claim 6 or 7, in which the support plate (15) is made of acrylonitrile butadiene styrene.

9. Housing according to any one of claims 6 to 8, in which a first face of the electrical component (5) is in contact with the platform (4), the housing (1) comprising a distal plate (38) which is in contact with a second face of the electrical component (5), which is fixed to the support plate (15) and which is configured to hold the electrical component (5) by clamping against the platform (4).

10. A housing according to any one of claims 1 to 9, wherein the second portion (21) of the heat pipe (14) has the second contact zone with the bus bar (8, 9, 10, 11), the contact between the heat pipe (14) and the bus bar (8, 9, 10, 11) being ensured by two flanges (24, 35) fixed to each other and between which the second portion (21) and the bus bar (8, 9, 10, 11) are held against each other.

11. Accumulator battery for a motor vehicle (V), comprising electrochemical cells and at least one electrical connection box (1) according to any one of claims 1 to 10.

12. Motor vehicle comprising an accumulator battery (2) according to claim 11.

Images