Battery module, battery module assembly comprising such module and associated motor vehicle

Abstract

The invention relates to a battery module comprising:-a rear portion (32) provided with a bottom wall (32A) intended to be placed in contact with a cooling circuit (27), the bottom wall having a thickness of less than 3 mm, and an edge (32B) extending along the bottom wall; and-a front portion (34) comprising a front wall (34A) bounded by side walls (34B) extending in the direction of the boundaries of the rear portion, the front portion and the rear portion delimiting a housing for receiving a plurality of storage cells (35), the front portion and the rear portion being assembled by overlapping the boundaries of the rear portion with the side walls of the front portion. The invention also relates to a battery module assembly (10) comprising such a module and to an associated motor vehicle.

Description

Technical Field

[0001] The present invention relates generally to the field of batteries.

[0002] More particularly, the present invention relates to a battery module.

[0003] The invention also relates to a battery module assembly comprising such a module.

[0004] The invention further relates to a motor vehicle equipped with such an assembly. Background Art

[0005] Electric vehicles (including hybrid vehicles) are generally equipped with an electric motor supplied with electric current from a plurality of battery modules.

[0006] Each battery module is typically formed by a housing which accommodates a plurality of battery cells.

[0007] Such a battery module is known, for example, from EP 3 637 495.

[0008] In this document, the housing has a rear part, on which a cover is provided, in this way defining a housing for receiving the stored cells. The rear part comprises a U-shaped part made in one piece, which has a bottom wall and two side walls. Two side cover plates complete the side walls of the rear part, in this way obtaining a closed structure.

[0009] The cover cooperates with the rear part by snapping onto the rear part. The entire housing (with the cover) then forms a rigid structure for receiving the battery cells.

[0010] A heat-conducting layer is provided at the location of the bottom wall of the rear part (typically the base of the U-shape of the U-shaped component), in this way enabling cooling of the battery cells.

[0011] However, this configuration of the rear section does not allow for sufficient cooling of the battery cells and therefore cannot effectively regulate the temperature of the battery cells. Summary of the invention

[0012] In order to remedy the above-mentioned disadvantages, the present invention proposes to improve the structure of the battery module in order to benefit from effective cooling of the battery cells contained in the module.

[0013] More specifically, according to the present invention, a battery module is provided, the battery module comprising:

[0014] a rear portion comprising a bottom wall intended to be placed in contact with the cooling circuit and an edge extending along the bottom wall, the thickness of the bottom wall being less than 3 mm, and

[0015] a front part comprising a front wall delimited by side walls extending in the direction of the edge of the rear part, the front part and the rear part delimiting a housing for receiving a plurality of storage cells,

[0016] The front and rear sections are assembled by overlapping the edges of the rear section with the side walls of the front section.

[0017] According to the invention, the thickness of the bottom wall of the rear part thus makes it possible to optimize the heat exchange between the battery cells and the cooling circuit.

[0018] Furthermore, assembling the front and rear portions by overlapping makes it possible to form a battery module housing that is rigid enough to house the battery cells while enabling the housing to deform in such a way as to accommodate the expansion of the cells caused by the heat generated by the cells themselves during charging and discharging.

[0019] The combination of these two features therefore enables efficient cooling of the battery cells even during the most constrained charging and discharging phases.

[0020] The following are further advantageous and non-limiting features of the battery module according to the invention, which may be considered individually or in all technically possible combinations:

[0021] - the height of the edge is less than 10 mm;

[0022] - Overlapping consists in assembling the edges of the rear part and the side walls of the front part by laser welding;

[0023] - Overlapping consists in assembling the edges of the rear section and the side walls of the front section by laser welding, brazing or mechanical fixing;

[0024] - the thickness of the bottom wall is between 0.3 mm and 2 mm;

[0025] - The edge is at an angle of approximately 90 degrees to the bottom wall;

[0026] - the rear portion is formed of an alloy including aluminum;

[0027] - the front part is stiffer than the rear part;

[0028] - A plurality of storage cells are glued to the bottom wall of the rear portion;

[0029] - the edge is interrupted at a corner; and

[0030] The side walls of the front part have, at their corners, elements for fixing them to receiving supports of the motor vehicle, said fixing elements being positioned facing the interrupted corners of the edges of the rear part.

[0031] The present invention also relates to a battery module assembly, the battery module assembly comprising:

[0032] a support for receiving the battery module, said receiving support being provided with a cooling circuit, and

[0033] - A battery module as described above, wherein a bottom wall of a rear portion of the battery module is positioned in contact with the cooling circuit.

[0034] A thermally conductive paste is placed between the cooling circuit and the bottom wall of the rear part of the battery module.

[0035] The receiving support comprises fixing means of the battery module intended to cooperate with fixing elements of the side walls of the front part of the battery module.

[0036] Finally, the invention relates to a motor vehicle equipped with such a battery module arrangement.

[0037] Of course, the various features, variants and embodiments of the present invention can be associated with each other in different combinations, as long as they are not incompatible or mutually exclusive. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The following description, provided by way of non-limiting examples with reference to the accompanying drawings, will clearly explain what the invention consists of and how it can be put into practice.

[0039] In the attached picture:

[0040] [ Figure 1 ] shows a schematic diagram of a motor vehicle equipped with a battery module assembly according to the present invention; and

[0041] [ Figure 2 ]yes Figure 1 Exploded view of the battery module assembly in . DETAILED DESCRIPTION

[0042] exist Figure 1 , a motor vehicle 1 has been shown which is provided with a battery module assembly 10 according to the invention.

[0043] The motor vehicle 1 is an electric or hybrid vehicle equipped with an electric motor. At least one battery module assembly 10 is designed to supply electric current to the electric motor of the motor vehicle 1 .

[0044] like Figure 1 and Figure 2 As shown, the battery module assembly 10 includes a support 20 for receiving a battery module (hereinafter also referred to as a “receiving support 20 ”), and at least one battery module 30 (hereinafter also referred to as a “module 30 ”).

[0045] Here, the receiving support 20 is locked to the motor vehicle 1 , for example, and the battery module 30 is mounted on the receiving support 20 .

[0046] Figure 2 1 shows a schematic exploded perspective view of the components of a battery module 30. The module 30 includes a rear portion 32, a front portion 34, and a plurality of battery cells 35 (for clarity, the front portion 34 is shown in FIG. Figure 2 Only one battery cell 35 is shown in FIG.

[0047] In this specification, the terms "front" and "rear" are used relative to the position of an element on a receiving support on which the element in question is mounted. The rear of the element is the side facing the receiving support on which the element is mounted, while the front is the side facing away from the receiving support.

[0048] The rear portion 32 is intended to come into contact with the cooling circuit 27 in the receiving support 20 .

[0049] The rear part 32 is made in one piece. The rear part is made of an alloy including aluminum, for example. Alternatively, the rear part can be made entirely of aluminum.

[0050] like Figure 2 As shown, the rear portion 32 includes a bottom wall 32A and an edge 32B extending along the bottom wall 32A. The edge 32B extends upward and forward from the bottom wall 32A. The edge 32B is at an angle of approximately 90 degrees to the bottom wall 32A. This 90-degree arrangement makes it possible to limit the overall size of the rear portion 32 (particularly when it is placed in the receiving support 20).

[0051] The height of edge 32B is less than or equal to 10 millimeters (mm). The height is preferably between 3 mm and 10 mm. This allows sufficient material to be used for assembling rear portion 32 and front portion 34 (assembly of rear portion 32 and front portion 34 will be described below).

[0052] Edge 32B has a rectangular overall profile. Here, as in Figure 2 As can be seen in FIG. 3 , the edge 32B is interrupted at the position of its corner. This shape of being truncated at the corner is conducive to enabling the battery module 30 to be fixed to the receiving support 20.

[0053] According to the invention, the bottom wall 32A advantageously has a thickness of less than 3 mm. This thickness of the bottom wall 32A then makes it possible to optimize the heat exchange between the battery cells 35 (also referred to in this description as "cells 35") and the cooling circuit 27. Furthermore, such a thickness makes it possible to reduce the overall weight of the battery module 30.

[0054] The thickness of the bottom wall 32A is preferably between 0.3 mm and 2 mm. The thickness is more preferably between 0.7 mm and 2 mm.

[0055] like Figure 2 As shown, the front portion 34 of the battery module 30 includes a front wall 34A, which is bounded by a side wall 34B extending from the front wall 34A. The side wall 34B of the front portion 34 extends in the direction of the edge 32B of the rear portion 32. In other words, the side wall 34B of the front portion 34 extends from the front wall of the battery module 30 toward the rear. By way of illustration, as shown in Figure 2 As can be seen in FIG. 1 , the rear portion 32 and the front portion 34 form an inverted shoe box, wherein the rear portion 32 forms a lid of the box and the front portion 34 forms a receiving portion of the box.

[0056] The front part 34 is made of aluminum, for example. The rigidity of the front part is greater than that of the rear part 32.

[0057] A stiffness test can be performed to compare the stiffness of the two parts (front part and rear part). During this test, the rear part 32 is fixed to a test support, for example, at a first point, and a mechanical stress is applied to the rear part 32 at a second point at a certain distance from the first point. The same mechanical stress is applied to the front part 34 fixed to the same test support, with the same distance between the fixing point and the stress application point. Then, if, after applying the above stress, a greater deformation is observed at the location of the rear part than at the location of the front part 34, the stiffness of the front part 34 is considered to be greater than the stiffness of the rear part 32.

[0058] like Figure 2 As shown, the side wall 34B of the front part has, at its corners, elements 34C for fixing it to the receiving support 20 of the motor vehicle 1 .

[0059] Here, these fixing elements 34C take the form of posts pierced by a longitudinal opening designed to cooperate with complementary fixing means 22A on the receiving support 20 .

[0060] In order to enable the fixing element 34C to cooperate with the means 22C of the receiving support 20, the fixing element 34C is positioned facing the interrupted corner of the bottom wall 32B of the rear portion 32. In this way, when the module 30 is mounted on the receiving support, the cooperation between the fixing element 34C of the front portion 34 and the fixing means 22C of the receiving support 20 is not hindered by the rear portion 32 of the module 30.

[0061] The front portion 34 and the rear portion 32 are assembled in such a way as to define a space for receiving a plurality of battery cells 35 ( Figure 2In other words, when they are assembled, the front part 34 and the rear part 32 form a housing of the battery module 30 that accommodates multiple battery cells 35.

[0062] According to the invention, the front portion 34 and the front portion 32 are advantageously assembled by overlapping the edges 32B of the rear portion 32 and the side walls 34B of the front portion 34 .

[0063] In this specification, "overlapping" refers to a method of assembling two metal walls placed end to end (aligned with each other) in such a way that a final surface that is generally smooth and has no thickness difference between the two assembled walls is obtained. Here, the two metal walls are, on the one hand, the edge 32B of the rear portion 32 and, on the other hand, the side wall 34B of the front portion 34. In other words, here, each portion of the edge 32B of the rear portion 32 is assembled to a corresponding portion of the side wall 34B of the front portion 34 (a portion positioned facing the edge 32B) by overlapping ( Figure 2 ).

[0064] This method of assembly by overlapping makes it possible to form a battery module housing that is rigid enough to accommodate the battery cells while allowing for expansion due to the heat generated by the cells themselves when they are charged or discharged.

[0065] Furthermore, this method allows the assembly of rear and front portions having different thicknesses and made of different materials while ensuring rigidity and expansion characteristics necessary for the battery module.

[0066] Here, the characteristics of the edge 32B as described above facilitate the overlap. In fact, a height of less than 10 mm and an orientation of the edge 32B at 90 degrees to the bottom wall 32A make it possible to improve the effectiveness of the overlap.

[0067] Here, the assembling by overlapping the edge 32B of the rear portion 32 with the side wall 34B of the front portion 34 is preferably achieved by welding (eg, laser welding).

[0068] Alternatively, the overlap may correspond to an assembly by brazing or even mechanical fixing, making it possible to obtain a smooth final surface without thickness differences between the edge of the rear portion and the side walls of the front portion.

[0069] A plurality of battery cells 35 are positioned in the housing formed by assembling the rear part 32 and the front part 34. The battery cells 35 are positioned, for example, next to each other. Here, for example, there are 16 battery cells.

[0070] In practice, each battery cell 35 is provided, for example, by Figure 2The gluing element 38 shown in FIG. 1 is glued to the bottom wall 32A of the rear part 32 of the module 30 .

[0071] Here, the cells 35 are, for example, cells with a flexible encapsulation, that is, the encapsulation of these cells 35 can be deformed during their insertion into the housing formed by the front part 34 and the rear part 32 and during charging or discharging of the cells. The front part 34 of the battery module 30 advantageously makes it possible to adapt to the deformation of the cells by virtue of its above-mentioned properties.

[0072] More specifically, the flexible encapsulated battery cell 35 includes a flexible outer encapsulation containing an electrolyte composed of an organic solution or a carbonate and lithium salt-based solution in its interior.

[0073] For example, it is an electrolyte of lithium-ion type, enclosed in an envelope consisting of a plastic film surrounded by a laminated aluminum film. The plastic film is intended to isolate the electrolyte contained in the cell 35 from the aluminum film.

[0074] These flexible encapsulated cells 35 which are well known to those skilled in the art will not be described in detail here.

[0075] In order to enable the electric motor of the motor vehicle 1 to be supplied with electric current, a battery module 30 , which is formed by a front part 34 and a rear part 32 and accommodates electric cells 35 , is positioned in the receiving support 20 .

[0076] like Figure 2 As shown in FIG. 1 , the receiving support 20 has here the overall shape of a parallelepiped. The receiving support comprises a bottom 22 of rectangular shape, from the edge of which protrude three side walls 23, 24, 25, which define between them a housing 21 for receiving the battery module 30. Here, the two side walls 23, 25 are positioned facing each other, while opposite the side wall 24, the receiving support 20 also comprises a side wall portion facing the side wall 24 (for the sake of clarity, Figure 2 not shown).

[0077] The receiving support 22 comprises a cooling circuit 27 at the level of its bottom 22. The cooling effect is obtained by the circulation of water in the cooling circuit 27, for example.

[0078] The cooling circuit 27 is designed to cool the battery cells 35 by conduction. To this end, the bottom wall 32 of the rear part 32 of the battery module 30 is positioned in contact with the bottom 22 of the receiving support 20 .

[0079] In order to improve the conduction phenomenon (and therefore improve cooling), a thermally conductive paste 26 is positioned between the bottom 22 of the receiving support 20 and the bottom wall 32 of the rear part 32 of the battery module 30. In other words, this thermally conductive paste 26 is positioned between the cooling circuit 27 and the bottom wall 32 of the rear part 32 of the battery module 30, in this way improving the effectiveness of the heat conduction between the cooling circuit 27 and the cells 35 (fixed to the bottom wall 32 of the rear part 32 of the battery module 30).

[0080] Such a thermally conductive paste 26 makes it possible to prevent the formation of air layers between the cooling circuit 27 and the battery cells 35 , which makes it possible to improve the conduction phenomena and thus the cooling.

[0081] Here, the receiving support 20 is formed, for example, in such a way as to seal against water drops or dust from penetrating into the battery module assembly 10. The sealing performance here is evaluated according to the IP67 level of the standard EN60529.

[0082] In order to enable the module 30 to be fixed to the receiving support 20, the bottom 22 of the receiving support 20 comprises fixing means 22A. These fixing means 22A are designed to cooperate with fixing elements 34C of the front part 34 of the side wall 34B of the module 30. There are as many fixing means 22A as fixing elements 34C on the side wall 34B of the front part 34 of the module 30.

[0083] Here, if Figure 2 As represented, the fixing means 22A are formed by lugs 22A projecting from the bottom 22 of the receiving support 20. These lugs 22A extend from the bottom 22 of the receiving support 20 forwards.

[0084] Here, each lug 22A cooperates by nesting with a corresponding longitudinal opening of a column 34C of a side wall 34B of the front portion 34 .

[0085] The battery module can be fixed to the receiving support in various ways. For example, in a variant not shown, the edge can be continuous around the entire periphery of the bottom wall (in other words, the edge can alternatively be continuous, including at its corners). In this case, the bottom wall of the rear part can include openings, which are located, for example, near the corners of the bottom wall of the rear part.

[0086] Thus, the module 30 can be fixed to the receiving support 20 by passing fixing elements (such as bolts) through the columns of the side walls of the front part and then through the openings in the bottom wall of the rear part, in this way cooperating with complementary fixing means in the bottom of the receiving support.

[0087] Generally speaking, the dimensions of the front and rear parts of the battery module and of the receiving support are adapted according to the number of battery cells accommodated in the module. In the above example, the dimensions are adjusted so that the battery module contains 16 cells.

[0088] The above-described embodiments relate only to a receiving support associated with one battery module.

[0089] The present invention is of course applicable to the case where the motor vehicle contains a plurality of battery modules, in which case it is conceivable to place a plurality of battery module assemblies 10 side by side in the motor vehicle. It is also conceivable to place a single receiving support that receives a plurality of battery modules (e.g., the battery modules are positioned side by side on the bottom of a single receiving support).

[0090] Finally, since the housing of the battery module is produced as two separate parts with different properties (eg material and thickness), it is possible to adapt the housing to the thermal forces generated by the battery cells and in this way to accommodate the expansion effects caused by the cells themselves.

[0091] According to the invention, a compromise can thus be achieved in the production of the housing in such a way as to obtain a certain rigidity while ensuring effective cooling of the cells. Given the thickness characteristics of the rear part of the housing of the battery module, the heat exchange between the cooling circuit and the cells is optimized, thereby enabling effective cooling of the battery module.

[0092] Ultimately, this makes it possible to reduce the weight of the battery module and thus advantageously reduce its production costs.

Claims

1. A battery module (30), comprising: a rear portion (32) comprising a bottom wall (32A) intended to be placed in contact with the cooling circuit (27) and an edge (32B) extending along the bottom wall (32A), the bottom wall (32A) having a thickness less than 3 mm, and a front portion (34) comprising a front wall (34A) delimited by side walls (34B) extending in the direction of an edge (32B) of the rear portion (32), the front portion (34) and the rear portion (32) defining a housing for receiving a plurality of storage cells (35), The front portion (34) and the rear portion (32) are assembled by overlapping the edge (32B) of the rear portion (32) with the side wall (34B) of the front portion (34).

2. The battery module (30) according to claim 1, wherein: The height of the edge (32B) is less than 10 mm.

3. The battery module (30) according to claim 1 or 2, wherein: The overlap includes assembling the edge (32B) of the rear portion (32) and the side wall (34B) of the front portion (34) by laser welding.

4. The battery module (30) according to any one of claims 1 to 3, wherein: The thickness of the bottom wall (32A) is between 0.3 mm and 2 mm.

5. The battery module (30) according to any one of claims 1 to 4, wherein: The front portion (34) has a stiffness greater than that of the rear portion (32).

6. The battery module (30) according to any one of claims 1 to 5, wherein: The edge (32B) is interrupted at the corner.

7. The battery module (30) according to claim 6, wherein: The side walls (34B) of the front part (34) have, at their corners, elements (34C) for fixing them to a receiving support (20) of the motor vehicle (1), said fixing elements (34C) being positioned facing the interrupted corners of the edges (32B) of the rear part (32).

8. A battery module assembly (10), comprising: a support (20) for receiving a battery module (30), said receiving support (20) being provided with a cooling circuit (27), and - The battery module (30) according to any one of claims 1 to 7, wherein the bottom wall (32A) of the rear portion (32) of the battery module (30) is positioned in contact with the cooling circuit (27).

9. The battery module assembly (10) as claimed in claim 8 when dependent on claim 7, wherein: The receiving support (20) comprises fixing means (22A) of the battery module (30), the fixing means (22A) being intended to cooperate with fixing elements (34C) of the side walls (34B) of the front part (34) of the battery module (30).

10. A motor vehicle (1) comprising a battery module assembly (10) according to claim 8 or 9.

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