Electrical connection box for rechargeable batteries, accumulator batteries, and motor vehicles

Abstract

The invention relates to an electrical connection box for a storage battery (2), comprising: - a platform (4) adapted to accommodate electrical components (5, 6, 7) and in which at least one circulation conduit (18) for a heat transfer fluid is provided, - a busbar (8, 9, 10, 11) ensuring 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 contact zone with the platform and a second portion (21) of which has a second contact zone with the busbar and / or with at least one of the electrical components. The invention also relates to a storage battery equipped with such a box and a motor vehicle equipped with such a battery. Figure for the abstract: Fig. 2

Description

Title of the invention: Electrical connection box for rechargeable batteries, rechargeable batteries and motor vehicles 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 battery of accumulators, a battery of accumulators equipped with such a box and a motor vehicle equipped with such a battery of accumulators. State of the art

[0003] Electric or hybrid vehicles are equipped with a battery pack comprising a casing which houses several electrochemical cells connected together and providing a high voltage at 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 safety electrical components (relay, fuse) in order to cut off the current when necessary. These components are positioned along a busbar through which the input or output current from the battery flows.

[0005] In certain situations, the battery supplies or receives a high electrical power. This is the case, for example, during so-called fast charging of the vehicle's battery, or when the vehicle must exert significant traction. In these situations, the flow of a high-intensity current generates a sharp increase in the battery's temperature, particularly at the battery terminals and bus bars.

[0006] Certain areas of the enclosure are susceptible to particularly high temperatures; these areas are commonly referred to as "hot spots." Components located at these hot spots are at increased risk of damage. To protect these components, systems exist for cooling the entire enclosure. However, given the large size of the enclosure, these solutions are not very effective and result in significant bulk and an excessive increase in the enclosure's weight. Presentation of the invention

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

[0008] According to one aspect, an electrical connection box for a rechargeable battery is proposed, comprising: - a platform adapted to accommodate electrical components and in which at least one heat transfer fluid circulation pipe is provided, - a busbar 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 busbar 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 busbar or on the components, which advantageously enables efficient cooling of the housing. Furthermore, the use of a heat pipe eliminates the need for a heat transfer fluid circulation circuit at the level of the electrical components or the busbar. The weight and size of the housing cooling elements are therefore advantageously reduced.

[0010] Other advantageous and non-limiting features of the electrical connection box according to the invention, taken individually or in all technically possible combinations, are as follows: - 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 heat transfer fluid circulation circuit which includes at least one pump. - a gallery adjacent to the circulation pipe is provided in the platform and the heat pipe is fixed to the platform by means of a screw configured to fit into a tapped hole provided in the platform and opening into the gallery. - a support plate is fixed to 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 having 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 presents 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 proposes a battery of accumulators for motor vehicles, comprising electrochemical cells and at least one electrical connection box according to the invention.

[0012] The invention also proposes a motor vehicle comprising a battery of accumulators according to the invention.

[0013] Of course, the various features, variants, and embodiments of the invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Detailed description of the invention

[0014] The following description with regard to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

[0015] On the attached drawings:

[0016] [Fig-1] is a schematic view of a motor vehicle according to the invention, equipped of a battery pack 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 the [Fig.2];

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

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

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

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

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

[0024] An electrical connection box according to an embodiment of the invention, as shown in [Fig. 1] and designated as a whole by the reference numeral 1, is used for connecting a battery 2 to the electrical network 3 of an electric or hybrid motor vehicle V. It thus equips the battery of accumulators 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 accumulator battery 2.

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

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

[0027] The electrical components 5, 6, 7 and the busbar 8, 9, 10, 11 are here attached to a mounting face F of the platform 4, here the upper face, by means of a support plate 15. Here, the support plate 15 is attached to the mounting face F of the platform 4 by means of studs 16 welded to the platform 4 and configured to fit into corresponding holes in the support plate 15 and to receive bolts that secure the support plate. The electrical components 4, 5, 6 and the busbar 8, 9, 10, 11 are here attached 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 busbar 8, 9, 10, 11 is configured to carry a high-intensity current, for example, a current greater than or equal to 500 Amperes. In this example, the busbar 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 terminal 12 for connection to the battery (portion 8) or between an electrical component and terminal 13 for connection to the electrical network of the motor vehicle V (portion 11).

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

[0030] The electromechanical relay 5 is configured to, during normal vehicle operation, reversibly break the connection between the storage battery 2 and the electrical network 3, for example after the parking of vehicle V. 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 designation) and is configured to cut off the electrical connection in the event of an accident of the motor vehicle V. It is controlled for example by a sensor of the motor vehicle, for example an impact sensor.

[0032] Fuse 7 is configured to break the electrical connection when it is traversed by an excessively high current, which would be caused for example by a short circuit.

[0033] During the use of the motor vehicle V, for example during a rapid charge of the accumulator battery 2 or when the traction of the vehicle is provided by an electric motor powered by the accumulator battery, the temperature of the omnibus 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 busbar 8, 9, 10, 11 to be dissipated, thus neutralizing the corresponding hot spots. To this end, the housing 1 includes at least one heat pipe 14 configured to dissipate at least a portion of the heat from the busbar 8, 9, 10, 11 to the platform 4. In order to prevent heat from accumulating in the platform 4, at least one circulation pipe 18 for a heat transfer fluid is provided there.

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

[0036] Here, as illustrated in more detail in [Fig. 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 refer here to the same type of entities, except that the pipes 18 are configured to be connected to a circulation circuit for a heat transfer fluid (for example, a glycol-based fluid). Such a circulation circuit (not shown and not the subject of the present invention) generally comprises a pump to force the circulation of the heat transfer fluid through the pipes 18, and a heat exchanger to cool this fluid.

[0037] Here, the pipes 18 have circular cross-sections. Fittings R for connecting to the heat transfer fluid circulation circuit are then screwed into the ends of the conduits 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 conduit 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 has five identical heat pipes 14, each in contact with both a portion of the busbar 8, 9, 10, 11 and the platform 4. Here, two heat pipes are in contact with a portion 10 of the busbar that 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 busbar. In practice, the number of heat pipes used per portion of the busbar depends on the amount of heat to be dissipated.

[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 straight portion 20 configured to establish a contact zone with the platform 4 and a second straight portion 21 orthogonal to the first straight portion 20 and configured to establish a second contact zone with the bus bar 8, 9, 10, 11. The first straight portion 21 and the second straight portion 22 are connected by an intermediate curved portion 22.

[0040] The heat pipe 14 has flat surfaces at the contact areas. More precisely, the heat pipe 14 is here a flat heat pipe, with an overall 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 straight portion 21 of the heat pipe 14, which establishes the second contact zone with the busbar 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 ([Fig.5]) ensuring the fixing of the heat pipe against the platform and a vertical fixing flange 24 ([Fig.6]) ensuring the fixing of the heat pipe 14 against the bus bar.

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

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

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

[0046] The vertical fixing flange 24 illustrated in [Fig.6] also has through holes 31, here four tapped holes, provided horizontally through the lateral arms, orthogonally to the main base 25.

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

[0048] On the other hand, the end faces of the arms of the vertical fixing flange 24 each have a notch forming a recess 30. This recess is configured to receive in a tight fit (without play or with little play) the omnibus 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 [Fig.7], the heat pipe 14 is placed against the receiving face F of the platform 4 so that its first straight portion 20 establishes the first contact zone with the platform 4 and so that its second straight 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 straight 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 arms 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 straight portion 20 of the heat pipe 14.

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

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

[0055] The vertical flange 24 is positioned so that the second straight 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 positioned in the recess 30 in a fitted 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 busbar 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 straight portion 21 of the heat pipe 14 is kept in contact with the first face of the portion 8 of the busbar, so that the closing flange 35 is kept in contact with the second face of the portion 8 of the busbar and in contact with the vertical flange 24.

[0057] Here, the contacts between the second straight portion 21 of the heat pipe 14 and the main base 25 of the vertical fixing flange 24, between the second straight portion 21 and the portion 8 of the bus bar, and between the portion 8 and the closing flange 35 are made through 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. Since the heat exchanges inside the heat pipe 14 are lower at the level of the second portion 21 (hotter 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 dissipation of the heat generated by the internal winding of the relay (which, for example, 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 to 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 clamping.

[0060] In order to ensure good heat dissipation from hot spots, the materials of the platform 4 and the flanges 23, 24, 34 have high thermal conductivity, for example greater than 100 Wm'.K1. For example these elements are made of aluminium or aluminium alloy.

[0061] The embodiments described above in connection with figures 1 to 9 are by no means limiting.

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

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

[0064] Several heat transfer fluid circulation lines and several galleries formed by extruding the platform have been described previously. The housing according to the invention is not limited to this configuration, and the lines and / or galleries can be formed by any other means, for example by drilling or molding the platform. Furthermore, the housing according to the invention can include any number of heat transfer fluid circulation lines, for example a single line, and any number of galleries or no galleries at all. In the latter case, the tapped holes provided on the receiving face of the platform, which allow the mounting flanges to be screwed in, either pass completely through the platform or are blind holes.

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

Claims

Demands

1. Electrical connection box for accumulator battery (2), comprising: - a platform (4) adapted to accommodate electrical components (5, 6, 7) and in which is provided at least one circulation pipe (18) of a heat transfer fluid, - a bus bar (8, 9, 10, 11) ensuring 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 area has a surface area at least equal to the surface area of ​​the second contact area.

3. 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, wherein the circulation line (18) is configured to be connected to a circulation circuit of a heat transfer fluid which includes at least one pump.

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

7. 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, wherein the support plate (15) is made of acrylonitrile butadiene styrene.

9. Housing according to any one of claims 6 to 8, wherein 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 clamp the electrical component (5) against the platform (4).

10. Housing according to any one of claims 1 to 9, wherein the second portion (21) of the heat pipe (14) has the second contact area 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. Motor vehicle (V) accumulator battery, comprising electrochemical cells and at least one electrical connection box (1) according to any one of claims 1 to 10.

12. Motor vehicle comprising a battery of accumulators (2) according to claim 11.

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