COOLING PANEL FOR A BATTERY TRAY WITH INTEGRATED CONNECTION STRIPS

Abstract

The invention relates to a cooling slab (5) for a battery tray comprising: - a first plate (14.1) of planar shape, - a second plate (14.2) having at least one zone of corrugated shape intended to define at least in part cooling channels, and - at least one connection strip (13) mechanically linked to the first plate (14.1) by means of an electrically insulating intermediate element (16) arranged between the first plate (14.1) and the connection strip (13). Figure 5

Description

Title of the invention: COOLING PANEL FOR A BATTERY TRAY WITH INTEGRATED CONNECTION STRIPS

[0001] The present invention relates to a cooling slab for a battery tray with integrated connection strips. The invention finds a particularly advantageous application with battery trays used with electric or hybrid type motor vehicles.

[0002] In a manner known per se, as illustrated in [Fig.l], a battery tray 1 comprises a lower tray 2 formed by a tray bottom 3, a frame 4 and a cooling slab 5.

[0003] The lower tray 2 delimits a space in which are arranged electrical power modules 7 associated with one or more module controllers 8 as well as connection and relay boxes 9. A computer box 10 supervises the module controllers 8 and is capable of communicating with one or more computers of the motor vehicle. A cover 11 is intended to close the assembly.

[0004] Each electric power module 7 comprises hundreds or even thousands of electrochemical cells containing substances capable of transforming chemical energy into electrical energy to supply current to the motor vehicle. The high-performance rechargeable electric power modules 7 are generally of the lithium-ion, lithium-ion polymer or lithium-metal polymer type. The grouping of the electrochemical cells into electric power modules 7 makes it possible to better protect them and facilitate their replacement in the event of a breakdown.

[0005] In order to avoid thermal runaway and to ensure operation of the cells at a suitable temperature, the electrical power modules 7 are cooled by the cooling slab 5 consisting of a set of metal plates between which a cooling fluid circulates. The cooling fluid evacuates the heat from the components mounted on the cooling slab 5 to the outside of the system. The cooling slab 5 can be arranged below or above the electrical power modules 7.

[0006] In order to electrically connect the electrical power modules 7 to each other, it is known to use connection strips 13 called "Busbars" according to English terminology. A connection strip 13 consists of a copper or aluminum conductor which conducts electricity between electrical components of the battery. [Fig. 2] shows a connection strip 13 establishing an electrical connection between a B+ terminal of a power module and a B- terminal of a module adjacent power.

[0007] The addition of the connection strips 13 requires additional assembly operations which are risky because the electrical power modules 7 are active and under high voltage. In order to carry out these assembly operations manually, the operator wears protective equipment including insulating gloves which complicate the handling of the small connection strips 13. For accessibility during assembly and disassembly, the connection strips 13 are mounted from above and screwed from above or snapped into housings provided for this purpose. The fact of having to mount them from above requires adding covers to the electrical power modules 7 to hide the connections and guarantee electrical protection for the operator with respect to the stripped areas of the connection strips 13.

[0008] The invention aims to effectively remedy the aforementioned drawbacks by proposing a cooling slab for a battery tray comprising: - a first flat-shaped plate, and - a second plate having at least one wavy-shaped area intended to define at least in part cooling channels, - said cooling slab further comprises at least one connection strip mechanically linked to the first plate by means of an electrically insulating intermediate element arranged between the first plate and the connection strip.

[0009] The invention thus makes it possible, by integrating the connection strips into the cooling slab, to avoid handling the connection strips in the terminal factory, which limits the risk of assembly errors and short circuits. The invention also makes it possible to eliminate screwing or snap-on interfaces for the connection strips and therefore to simplify the terminals of the electrical power modules.

[0010] The invention also allows the cooling of the connection strips, which allows the reduction of their section.

[0011] The non-functional areas of the connection strips can also be isolated directly in the manufacturing process of a cooling slab and / or using a process for applying a gap filler layer in the terminal factory, which provides a weight saving and a reduction in manufacturing cost.

[0012] The connection strips integrated into the cooling slab can also serve as an indexing reference for positioning the electrical power modules on the cooling slab.

[0013] In the case of using a dielectric fluid, the connection strips can also serve as a dielectric fluid supply conduit to cool the power electrical modules.

[0014] According to one embodiment of the invention, the connection strip is arranged inside a through opening defining a receiving housing for the connection strip made in the first plate.

[0015] According to one embodiment of the invention, the intermediate element extends between a periphery of the connection strip and an internal face delimiting the through opening.

[0016] According to one embodiment of the invention, the second plate comprises at least one perforated zone arranged opposite the connection strip to electrically insulate the connection strip from the second plate.

[0017] According to one embodiment of the invention, said cooling slab comprises at least one support element arranged against a face of the second plate facing a side opposite to the first plate.

[0018] According to one embodiment of the invention, a face of the connection strip facing away from the electrical power modules is covered by a layer of electrically insulating material chosen from: adhesive, an overmolded plastic layer, or an attached cover.

[0019] According to one embodiment of the invention, a cavity in which a dielectric fluid circulates extends between the second plate and a portion of the first plate carrying the connection strip so as to electrically insulate the second plate with respect to the connection strip.

[0020] According to one embodiment of the invention, a space-filling layer covers areas of the first plate intended to come into contact with electrical power modules and a face of the at least one connection strip intended to be turned towards the electrical power modules with the exception of connection areas with the electrical power modules.

[0021] According to one embodiment of the invention, the space-filling layer is chosen from a thermal paste, a layer of adhesively deposited insulation, a cover snapped onto the first plate or an overmolding layer.

[0022] The invention also relates to an assembly comprising at least one electrical power module and a cooling slab as previously defined, said electrical power module comprising at least one electrical track intended to establish an electrical connection with an end portion of the connection strip.

[0023] According to one embodiment of the invention, the end portion of the connection strip is bent relative to the rest of the connection strip to obtain a spring effect and a pressing force against the electrical track.

[0024] According to one embodiment of the invention, the end portion of the connection strip comprises a connection pad intended to cooperate with a conductive housing of corresponding shape carried by the electrical power module.

[0025] According to one embodiment of the invention, the end portion of the connection strip and the connection pad comprise a through opening allowing a dielectric fluid to pass from the cooling slab to the electrical power module.

[0026] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only for illustrative purposes but in no way limit the invention.

[0027] [Fig-1] [Fig. 1], already described, is an exploded perspective view of a standard battery tray with which the invention can be implemented.

[0028] [Fig.2] [Fig.2] is a detailed perspective view of connection strips according to the state of the art used to establish electrical connections between electrical power modules of the battery tray of [Fig.l].

[0029] [Fig.3] [Fig.3] is an exploded perspective view of a cooling slab provided with a flat-shaped upper plate and a lower plate having at least one wavy-shaped area intended to be assembled with each other.

[0030] [Fig.4] [Fig.4] is an exploded perspective view of a top plate and its connection strips according to the invention.

[0031] [Fig.5] [Fig.4] is a detailed perspective view illustrating an integration of connection strips in an upper plate of a cooling slab according to the invention.

[0032] [Fig.6] [Fig.6] is a perspective view of a lower plate according to the invention equipped with openwork areas made opposite the connection bars.

[0033] [Fig.7] [Fig.7] is a sectional view of an embodiment in which a support element is arranged against a lower face of connection strips to provide electrical insulation of the connection strips from the environment under the cooling slab.

[0034] [Fig.8] [Fig.8] is a sectional view of an embodiment in which an adhesive tape is adhered against an underside of connection strips to provide electrical insulation of the connection strips from the environment beneath the cooling slab.

[0035] [Fig.9] [Fig.9] is a sectional view of an embodiment in which a overmolding is carried out on the lower face of the connection strips to ensure electrical insulation of the connection strips from the environment under the cooling slab.

[0036] [Fig. 10] [Fig. 10] is a sectional view of an embodiment in which a circulation cavity of a dielectric cooling fluid is arranged on the side from a lower face of connection strips.

[0037] [Fig. 11] [Fig. 11] is a top view of a top plate on which an electrically insulating gap filler layer is deposited.

[0038] [Fig. 12] [Fig. 12] is a perspective view of electrical power modules provided with conductive tracks allowing the connection terminals of the power modules to be moved downwards towards the connection strips according to the invention.

[0039] [Fig. 13] [Fig. 13] is a sectional view illustrating a connection zone between an electrical track of an electrical power module and a connection strip according to the invention.

[0040] [Fig. 14] [Fig. 14] is a detailed perspective view illustrating the folded shape of an end portion of a connection strip intended to be connected to an electrical track of an electrical power module.

[0041] [Fig. 15] [Fig. 15] is a perspective view illustrating the connection of electrical power modules to connection strips provided with connection pads.

[0042] [Fig. 16] [Fig. 16] is a sectional view illustrating an embodiment in which a connection strip provided with a connection pad comprises an opening for the passage of a cooling fluid towards an electrical power module.

[0043] Identical, similar, or analogous elements retain the same reference from one figure to another.

[0044] In the remainder of the description, the relative terms of the type "upper", "lower", "top", "bottom" are understood by reference to their common meaning that a person looking at a battery pack in the position of use inside a motor vehicle would give them.

[0045] [Fig. 3] shows a cooling slab 5 for a battery tray comprising a first plate 14.1 of planar shape and a second plate 14.2 having at least one corrugated area 15 intended to define at least in part cooling channels. The second plate 14.2 is fixed to the first plate 14.1 from below. The first plate 14.1 is thus called the upper plate and the second plate 14.2 is called the lower plate. The corrugated areas 15 of the second plate 14.2 are configured to form a network of cooling channels homogeneous in flow rate and pressure of a coolant inside the cooling slab 5. The first plate 14.1 and the second plate 14.2 are preferably made of a metallic material, in particular aluminum. The plates 14.1, 14.2 each have a thickness of a few millimeters.

[0046] As can be seen in Figures 4 and 5, at least one connection strip 13 is mechanically connected to the first plate 14.1 by means of an electrically insulating intermediate element 16 arranged between the first plate 14.1 and the strip connection strip 13. The intermediate element 16 makes it possible to prevent a short-circuit in the electrical network of the battery tray 1. In this case, several connection strips 13 are integrated in the first plate 14.1. A connection strip 13 may have a rectilinear or curved shape.

[0047] Advantageously, a connection strip 13 is arranged inside a through opening 19 defining a receiving housing for the connection strip 13 made in the first plate 14.1. Coolant inlet and outlet end pieces 17 may also be integrated on the first plate 14.1. The connection strips 13 and the end pieces 17 may be arranged in corresponding through openings 19 during the same operation.

[0048] An intermediate element 16 extends between a periphery of a connection strip 13 (in other words a lateral edge of the connection strip 13) and an internal face delimiting the through opening 19. An intermediate element 16 can be made of a material such as, for example, plastic, ceramic, wood, rubber or any other insulating material having sufficient mechanical properties to hold the connection strip 13 in position in the housing 19 created on the first plate 14.1.

[0049] The intermediate element 16 can in particular be force-fitted into the housing of the first plate 14.1 or overmolded.

[0050] Indeed, in order to obtain a cooling slab 5 made of metal, in particular aluminum, the first and second plates 14.2 are assembled together by a process called brazing carried out at high temperature by passing through a furnace. According to this process, it is possible to provide an intermediate element 16 made of an electrically insulating material which acquires, during passage through the furnace, a good capacity for adhesion to the two walls present, namely the internal face delimiting the housing 19 and the periphery of the connection strip 13. The intermediate elements 16 can thus be constituted by swelling inserts overmolded on the upper plate.

[0051] Alternatively, it is possible to use the temperature of the brazing process to cast an insulating material and take advantage of the hot walls to obtain a robust overmolding of the intermediate element 16 around the receiving housing 19 of the connection strip 13.

[0052] Any other method for mechanically connecting the connection strips 13 to the first plate 14.1 by means of intermediate elements 16 can be implemented.

[0053] As can be seen in Figures 5 and 6, the second plate 14.2 comprises at least one openwork zone 21 arranged opposite a corresponding connection strip 13 to electrically insulate the connection strip 13 with respect to the second plate 14.2. Due to the air insulation, the environment under the cooling slab 5 is protected from any risk of electrical short circuit.

[0054] Furthermore, at least one support element 22 called a "holding pad" according to English terminology can be arranged against a face of the second plate 14.2 facing a side opposite to the first plate 14.1, as shown in [Fig.7]. In this case, several support elements 22 can be arranged between the second lower plate 14.2 and the bottom of the tray 3 or any other part of the structure of the battery tray.

[0055] These support elements 22 make it possible to stiffen and support the cooling slab 5 which tends to bend under the weight of the electrical power modules 7 positioned above the cooling slab 5. The support elements 22 can be made of a thermally insulating foam to avoid dissipating calories in unsuitable areas. Alternatively, the support element(s) 22 can be made of any other thermally and electrically insulating material suitable for the application. 1. Alternatively, the cooling slab 5 can be arranged above the electrical power modules 7.

[0056] Alternatively or in addition, one face of the connection strip 13 facing a side opposite the electrical power modules 7 is covered by a layer 25 of electrically insulating material.

[0057] In the embodiment of [Fig.8], an adhesive 26 covers the lower face of several connection strips 13 arranged next to each other.

[0058] In the embodiment of [Fig.9], an overmolded plastic layer 27 individually covers a lower face of a correspondingly shaped connection strip 13. The overmolded plastic layer 27 can be obtained during the overmolding operation of the intermediate element 16.

[0059] Alternatively, the layer 25 of electrically insulating material is an attached cover.

[0060] In the embodiment of [Fig. 10], a cavity 30 in which a dielectric fluid circulates extends between the second plate 14.2 and a portion of the first plate 14.1 carrying the connection strip 13 so as to electrically insulate the second plate 14.2 with respect to the connection strip 13.

[0061] As illustrated in [Fig. 11], a gap filler layer 31 covers areas of the first plate 14.1 intended to come into contact with electrical power modules 7. The layer 31 also covers a face of the connection strips 13 intended to be turned towards the electrical power modules 7 with the exception of the connection areas with the electrical power modules 7. In other words, only the non-functional area of the connection strips 13 is covered by the gap filler layer while the areas of the connection strips 13 necessary for connection with the 7 power electrical modules are not covered and left accessible.

[0062] Preferably, the gap-filling layer 31 is made of a thermal paste that can be made from silicone having good flexibility, good mechanical strength and good electrical insulation properties. The thermal paste can be loaded with heat-conducting particles (metallic and / or ceramic) in order to improve its thermal conductivity.

[0063] Alternatively, the layer 31 is a layer of adhesively deposited insulation or a cover snapped onto the first plate 14.1 before mounting over the electrical power modules 7 or an overmolding layer.

[0064] As can be seen in Figures 12 and 13, the electrical power modules 7 may comprise electrical tracks 33 intended to establish electrical connections with end portions 34 of the connection strips 13. The electrical tracks 33 are configured to move a corresponding connection terminal B+, B- towards a lower part of the electrical power module 7. In [Fig. 12], the arrows F1 represent the direction of the electric current

[0065] As illustrated in [Fig. 14], the end portion 34 of the connection strip 13 can be bent relative to the rest of the connection strip 13 to obtain a spring effect and a pressing force against the electrical track 33. The end portion 34 is bent vertically upwards. For this purpose, it is possible to provide a cutout 35 around the end portion 34 in order to allow the movement of the end portion 16 relative to the intermediate element 16.

[0066] When installing the electrical power module 7, the connection between the electrical track 33 and a connection strip 13 is created by contact thanks to the clamping pressure force and the plating of the electrical power module 7 on the cooling slab 5. The folding of the end portion 34 makes it possible to guarantee the electrical contact between the connection strip 13 and the electrical power module 7 independently of the tolerance intervals of the different components of the assembly.

[0067] In the embodiment of [Fig. 15], the end portions 34 of the connection strips 13 each comprise a connection pad 37 intended to cooperate with a conductive housing 38 of corresponding shape carried by a corresponding electrical power module 7. Such an interconnection configuration allows the indexing and positioning of the electrical power modules 7 relative to the connection pads 37.

[0068] As illustrated in [Fig. 16], the end portion 34 of the connection strip 13 and the connection pad 37 may comprise a through opening 40 allowing a dielectric fluid to pass from the cooling slab 5 to the electrical power module 7. The dielectric liquid thus makes it possible to cool the various electrochemical cells 41 arranged inside the electrical power module 7.

Claims

Claims

1. Cooling slab (5) for a battery tray (1) comprising: - a first plate (14.1) of planar shape, and - a second plate (14.2) having at least one corrugated zone (15) intended to define at least in part cooling channels, characterized in that said cooling slab (5) further comprises at least one connection strip (13) mechanically linked to the first plate (14.1) by means of an electrically insulating intermediate element (16) arranged between the first plate (14.1) and the connection strip (13).

2. Cooling slab according to claim 1, characterized in that the connection strip (13) is arranged inside a through opening (19) defining a receiving housing for the connection strip (13) produced in the first plate (14.1).

3. Cooling slab according to claim 2, characterized in that the intermediate element (16) extends between a periphery of the connection strip (13) and an internal face delimiting the through opening (19).

4. Cooling slab according to any one of claims 1 to 3, characterized in that the second plate (14.2) comprises at least one perforated zone (21) arranged opposite the connection strip (13) to electrically insulate the connection strip (13) from the second plate (14.2).

5. Cooling slab according to any one of claims 1 to 4, characterized in that it comprises at least one support element (22) arranged against a face of the second plate (14.2) facing a side opposite to the first plate (14.1).

6. Cooling slab according to any one of claims 1 to 5, characterized in that a face of the connection strip (13) facing a side opposite to electrical power modules (7) is covered by a layer (25) of electrically insulating material chosen from: adhesive (26), an overmolded plastic layer (27), or an attached cover.

7. Cooling slab according to any one of claims 1 to 5, characterized in that a cavity (30) in which a dielectric fluid circulates extends between the second plate (14.2) and a portion of the first plate (14.1) carrying the connection strip (13) so as to electrically insulate the second plate (14.2) from the connection strip (13).

8. Cooling slab according to any one of claims 1 to 7, characterized in that a space-filling layer (31) covers areas of the first plate (14.1) intended to come into contact with electrical power modules (7) and a face of the at least one connection strip (13) intended to be turned towards the electrical power modules (7) with the exception of connection areas with the electrical power modules (7).

9. Cooling slab according to claim 8, characterized in that the space-filling layer (31) is chosen from a thermal paste, a layer of adhesively deposited insulation, a cover snapped onto the first plate (14.1) or an overmolding layer.

10. Assembly comprising at least one electrical power module (7) and a cooling slab (5) as defined according to any one of the preceding claims, characterized in that said electrical power module (7) comprises at least one electrical track (33) intended to establish an electrical connection with an end portion (34) of the connection strip (13).

11. Assembly according to claim 10, characterized in that the end portion (34) of the connection strip (13) is bent relative to the rest of the connection strip (13) to obtain a spring effect and a pressing force against the electrical track (33).

12. Assembly according to claim 10, characterized in that the end portion (34) of the connection strip (13) comprises a connection pad (37) intended to cooperate with a conductive housing (38) of corresponding shape carried by the electrical power module (7).

13. Assembly according to claim 12, characterized in that the end portion (34) of the connection strip (13) and the connection pad (37) comprise a through opening (40) allowing passage of a dielectric fluid from the cooling slab (5) to the electrical power module (7).

Images