Storage battery module, storage battery module assembly comprising such a module and associated motor vehicle

Abstract

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

Description

ACCUMULATOR BATTERY MODULE, BATTERY MODULE ASSEMBLY OF ACCUMULATORS COMPRISING SUCH A MODULE AND ASSOCIATED MOTOR VEHICLE TECHNICAL FIELD OF THE INVENTION

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

[0002] The invention relates more particularly to an accumulator battery module.

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

[0004] It also concerns a motor vehicle equipped with such a unit. STATE OF THE ART

[0005] Electrically powered motor vehicles, including hybrid thermal and electric vehicles, are generally equipped with an electric motor supplied with current by a plurality of storage battery modules.

[0006] Conventionally, each storage battery module is formed from a housing that houses a plurality of storage battery cells.

[0007] Such an accumulator battery module is known, for example, from document EP3637495.

[0008] In this document, the housing has a rear part topped by a cover so as to define a housing for the accumulator cells. The rear part has a U-shaped part, made of a single piece, with a bottom wall and two side walls. Two side cover plates complete the side walls of the rear part so as to obtain a closed structure.

[0009] The cover engages with the rear part by snapping into place. The entire housing (including the cover) then forms a rigid structure to accommodate the accumulator battery cells.

[0010] A thermally conductive layer is arranged at the bottom wall of the rear part (typically the base of the U of the U-shaped part) so as to allow the cooling of the accumulator battery cells.

[0011] However, such a configuration of the rear part does not allow a sufficient cooling of the battery cells and therefore does not allow their temperature to be effectively regulated. PRESENTATION OF THE INVENTION

[0012] In order to overcome the aforementioned drawbacks, the present invention proposes to improve the structure of the accumulator battery module in order to benefit from efficient cooling of the accumulator battery cells included in this module.

[0013] More particularly, the invention provides an accumulator battery module comprising: - a rear part provided with a bottom wall, intended to be placed in contact with a cooling circuit, and with a border running along the bottom wall, the bottom wall having a thickness of less than 3 millimeters, and - a front part comprising a front wall bordered by a side wall, said side wall extending towards the edge of the rear part, the front part delimiting with the rear part a housing for receiving a plurality of accumulator cells, the front part and the rear part being assembled by grooving said edge of the rear part and the side wall of the front part.

[0014] Thus, according to the present invention, the thickness of the bottom wall of the rear part makes it possible to optimize the thermal exchanges between the accumulator battery cells and the cooling circuit.

[0015] In addition, the assembly by grooving of the front part and the rear part makes it possible to form a sufficiently rigid accumulator battery module housing to contain the accumulator battery cells while allowing deformation of this housing so as to contain the expansion of the cells resulting from the thermal forces generated by the cells themselves during their charging and discharging.

[0016] Thus, these two characteristics combined ensure good thermal cooling of the cells, even during the most demanding charging and discharging phases.

[0017] Other advantageous and non-limiting characteristics of the accumulator battery module according to the invention, taken individually or in all technically possible combinations, are the following: - the border has a height of less than 10 millimeters; - the joist includes an assembly of the edge of the rear part and the side wall of the front part by laser welding; - the joist includes an assembly of the edge of the rear part and the side wall of the front part by laser welding, brazing or mechanical fixing; - the thickness of the bottom wall is between 0.3 and 2 millimeters; - the border forms an angle of around 90 degrees with the back wall; - the rear part is formed from an alloy including aluminum; - the front part has greater rigidity than the rear part; - the plurality of accumulator cells is fixed to the bottom wall of the rear part by gluing; - said border is interrupted at the corners; and - the side wall of the front part has, at its corners, elements for fixing to a support for receiving a motor vehicle, said fixing elements being positioned opposite the interrupted corners of the edge of the rear part.

[0018] The invention also relates to a storage battery module assembly comprising: - a support for receiving a storage battery module, said support for receiving being provided with a cooling circuit, and - a storage battery module as previously introduced, the bottom wall of the rear part of said storage battery module being positioned in contact with said cooling circuit.

[0019] Thermal paste is provided between the cooling circuit and the bottom wall of the rear part of the storage battery module.

[0020] The receiving support comprises means for fixing said accumulator battery module, said fixing means being intended to cooperate with the fixing elements of the side wall of the front part of said accumulator battery module.

[0021] The invention finally relates to a motor vehicle equipped with such an accumulator battery module assembly.

[0022] Of course, the various features, variants and embodiments of the invention can be combined with each other according to various combinations as long as they are not incompatible or mutually exclusive. DETAILED DESCRIPTION OF THE INVENTION

[0023] 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.

[0024] On the attached drawings:

[0025] [Fig. 1] represents a schematic view of a motor vehicle equipped with a set of accumulator battery modules according to the invention; and

[0026] [Fig. 2] is an exploded view of the storage battery module assembly of Figure 1.

[0027] In Figure 1, there is shown a motor vehicle 1 equipped with a set 10 of accumulator battery modules according to the invention.

[0028] This motor vehicle 1 is an electric or hybrid motor vehicle equipped with an electric motor. At least one set 10 of storage battery modules is designed to supply electric current to the electric motor of the motor vehicle 1.

[0029] As shown in Figures 1 and 2, the storage battery module assembly 10 comprises a storage battery module receiving support 20 (also called "receiving support 20" in the following) and at least one storage battery module 30 (also called "module 30" in the following).

[0030] The receiving support 20 is for example here secured to the motor vehicle 1, while the accumulator battery module 30 is attached to the receiving support 20.

[0031] Figure 2 shows a schematic exploded perspective view of the elements included in the storage battery module 30. This module 30 includes a rear portion 32, a front portion 34 and a plurality of storage battery cells 35 (for reasons of clarity, only one storage battery cell 35 is shown in Figure 2).

[0032] In this description, the terms "front" and "rear" are used in relation to the positioning of the element on the receiving support (on which The rear of this element designates the side facing the receiving support on which the element is reported, while the front designates the side facing away from this receiving support.

[0033] The rear part 32 is intended to be placed in contact with a cooling circuit 27 present in the receiving support 20.

[0034] The rear portion 32 is made from a single piece. It is for example formed from an alloy comprising aluminum. Alternatively, it may be formed solely from aluminum.

[0035] As shown in Figure 2, the rear portion 32 comprises a bottom wall 32A and a border 32B running along the bottom wall 32A. The border 32B rises forward from the bottom wall 32A. This border 32B forms an angle of the order of 90 degrees with the bottom wall 32A. This 90-degree arrangement makes it possible to limit the size of the rear portion 32 (in particular when it is arranged in the receiving support 20).

[0036] The edge 32B has a height less than or equal to 10 millimeters (mm). Preferably, this height is between 3 and 10 mm. This ensures that there is enough material to assemble the rear portion 32 and the front portion 34 (the assembly of the rear portion 32 and the front portion 34 is described below).

[0037] The edge 32B generally has a rectangular profile. Here, as can be seen in FIG. 2, the edge 32B is interrupted at its corners. This truncated shape at the corners is advantageous for allowing the accumulator battery module 30 to be fixed to the receiving support 20.

[0038] Advantageously according to the invention, the bottom wall 32A has a thickness of less than 3 mm. This thickness of the bottom wall 32A then makes it possible to optimize the heat exchanges between the storage battery cells 35 (also called “cells 35” in this description) and the cooling circuit 27. Furthermore, such a thickness makes it possible to reduce the total mass of the storage battery module 30.

[0039] Preferably, the thickness of the bottom wall 32A is between 0.3 and 2 mm. More preferably, it is between 0.7 and 2 mm.

[0040] As shown in FIG. 2, the front portion 34 of the storage battery module 30 comprises a front wall 34A bordered by a side wall 34B, extending from the front wall 34A. The side wall 34B of the front portion 34 extends towards 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, towards the rear of the storage battery module 30. For illustration purposes, as seen in FIG. 2, the rear portion 32 and the front portion 34 form an inverted shoe box, with the rear portion 32 forming the lid of this box and the front portion 34 the container of this box.

[0041] The front part 34 is for example formed from aluminum. It has a greater rigidity than the rear part 32.

[0042] To compare the rigidity between the two parts (front and rear), a rigidity test can be implemented. During this test, the rear part 32 is for example fixed to a test support at a first point and a mechanical stress is applied to this rear part 32 at a second point spaced from the first. 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 point of application of the stress. It is then considered that the front part 34 has a rigidity greater than that of the rear part 32 if, after the application of the mentioned stress, a greater deformation is observed at the rear part than at the front part 34.

[0043] As shown in Figure 2, the side wall 34B of the front part has, at its corners, fixing elements 34C to the receiving support 20 of the motor vehicle 1.

[0044] These fixing elements 34C are presented here in the form of columns pierced with a longitudinal opening designed to cooperate with complementary fixing means 22A present on the receiving support 20.

[0045] In order for these fixing elements 34C to be able to cooperate with the means 22C of the receiving support 20, the fixing elements 34C are positioned opposite the interrupted corners of the bottom wall 32B of the rear part 32. In this way, when the module 30 is attached to the receiving support, the cooperation between the fixing elements 34C of the front part 34 and the fixing means 22C of the receiving support 20 is not hindered by the rear part 32 of the module 30.

[0046] The front part 34 and the rear part 32 are assembled so as to delimit a housing for receiving a plurality of accumulator battery cells 35 (only one of which is visible in FIG. 2). In other words, when assembled, the front portion 34 and the rear portion 32 form a housing of the storage battery module 30 housing the plurality of storage battery cells 35.

[0047] Advantageously according to the invention, the front part 34 and the front part 32 are assembled by grooving the edge 32B of the rear part 32 and the side wall 34B of the front part 34.

[0048] In this description, the term "joining" means a method of assembling two metal walls placed end to end (in the extension of one another) so as to obtain a final surface that is generally smooth and without any thickness difference between the two assembled walls. Here, the two metal walls are, on the one hand, the edge 32B of the rear part 32 and, on the other hand, the side wall 34B of the front part 34. In other words, here, each portion of the edge 32B of the rear part 32 is assembled by joisting to the corresponding part (i.e. located opposite the portion of the edge 32B) of the side wall 34B of the front part 34 (figure 2).

[0049] This method of joist assembly makes it possible to form a battery module housing that is rigid enough to contain the battery cells while allowing for expansion resulting from the thermal stresses generated by the cells themselves during charging and discharging.

[0050] Furthermore, this method allows the assembly of a rear part and a front part with different thicknesses and made of different materials while guaranteeing the rigidity and expansion properties essential to a storage battery module.

[0051] The grooving is here favored by the properties of the edge 32B as described previously. Indeed, a height less than 10 mm and an orientation of the edge 32B at 90 degrees relative to the bottom wall 32A make it possible to improve the efficiency of the grooving.

[0052] Preferably here, the assembly by grooving of the edge 32B of the rear part 32 and the side wall 34B of the front part 34 is carried out by welding. This welding is for example laser welding.

[0053] Alternatively, the grooving can correspond to an assembly by brazing or even by mechanical fixing, making it possible to obtain a smooth final surface, without thickness offset between the edge of the rear part and the side wall of the front part.

[0054] The plurality of storage battery cells 35 is positioned in the housing formed by the assembly of the rear part 32 and the front part 34. The storage battery cells 35 are for example positioned next to each other. There are for example sixteen of them here.

[0055] In practice, each cell 35 of the accumulator battery is for example fixed by gluing, by an adhesive element 38 shown in FIG. 2, on the bottom wall 32A of the rear part 32 of the module 30.

[0056] The cells 35 are for example here cells with a flexible envelope, that is to say cells 35 whose envelopes can deform during their insertion into the housing formed by the front part 34 and the rear part 32 and during their charging and discharging. Advantageously, the front part 34 of the accumulator battery module 30 makes it possible to contain the deformation of the cells thanks to its properties described previously.

[0057] More particularly, the soft-shell cells 35 comprise a soft outer shell which contains inside an electrolyte of organic solution or of a solution based on carbonate and lithium salts.

[0058] For example, this is a lithium-ion electrolyte, wrapped in a casing 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.

[0059] These flexible-envelope cells 35, well known to those skilled in the art, will not be described in more detail here.

[0060] In order to enable the electric current to be supplied to the electric motor of the motor vehicle 1, the accumulator battery module 30 (formed by the front part 34, the rear part 32 and housing the cells 35) is positioned in the receiving support 20.

[0061] As shown in Figure 2, the receiving support 20 here has a generally parallelepiped shape. It comprises a base 22 of rectangular shape, from the edges of which rise three side walls 23, 24, 25 which delimit between them a receiving housing 21 of the accumulator battery module 30. Here, the two side walls 23, 25 are located opposite one another while opposite the side wall 24, the receiving support 20 also has a side wall portion extending opposite this side wall 24 (but which is not shown in Figure 2 for the sake of clarity).

[0062] The receiving support 22 comprises, at its bottom 22, a cooling circuit 27. The cooling effect is for example obtained from the circulation of water in the cooling circuit 27.

[0063] The cooling circuit 27 is designed to cool, by conduction, the storage battery cells 35. For this, the bottom wall 32 of the rear part 32 of the storage battery module 30 is positioned in contact with the bottom 22 of the receiving support 20.

[0064] In order to improve the conduction phenomenon (and therefore the cooling), a thermal 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 storage battery module 30. In other words, this thermal paste 26 is positioned between the cooling circuit 27 and the bottom wall 32 of the rear part 32 of the storage battery module 30 so as to improve the efficiency of the thermal conduction between the cooling circuit 27 and the cells 35 (fixed on the bottom wall 32 of the rear part 32 of the storage battery module 30).

[0065] This thermal paste 26 makes it possible to prevent the formation of an air gap between the cooling circuit 27 and the cells 35, which makes it possible to improve the conduction phenomenon and therefore the cooling.

[0066] The receiving support 20 is for example formed here so as to be impervious to water drops or dust which could enter the accumulator battery module assembly 10. The sealing is here evaluated according to the IP67 standard according to the EN60529 standard.

[0067] In order to allow 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 the 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 there are fixing elements 34C on the side wall 34B of the front part 34 of the module 30.

[0068] Here, as shown in Figure 2, 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, towards the front of the receiving support 20.

[0069] Each lug 22A cooperates here, by fitting, with an opening corresponding longitudinal of a column 34C of the side wall 34B of the front part 34.

[0070] The attachment of the storage battery module to the receiving support can be carried out in different ways. For example, according to a variant not shown, the border can be continuous over the entire periphery of the bottom wall (in other words, as a variant, the border can be continuous, including at its corners). In this case, the bottom wall of the rear part can have openings, for example located near the corners of the bottom wall of the rear part.

[0071] Thus, the module 30 can be fixed to the receiving support 20 by passing fixing elements (such as screws) through the columns of the side wall of the front part, then through the openings of the bottom wall of the rear part so as to cooperate with complementary fixing means present in the bottom of the receiving support.

[0072] Generally, it should be noted that the dimensions of the front and rear parts of the storage battery module, as well as those of the receiving support, are adapted according to the number of storage battery cells housed in the module. In the example described above, the dimensions are adjusted so that the storage battery module contains 16 cells.

[0073] The embodiment described above only concerns a receiving support associated with a storage battery module.

[0074] The present invention is of course applicable in the case where a plurality of accumulator battery modules are included in the motor vehicle. In such a case, a plurality of sets 10 of accumulator battery modules juxtaposed next to each other in the motor vehicle may be considered. A single receiving support may also be considered accommodating a plurality of accumulator battery modules (the accumulator battery modules being positioned, for example, next to each other on the bottom of the single receiving support).

[0075] Finally, thanks to the production of the accumulator battery module housing in two separate parts with different characteristics (in materials and thicknesses for example), it is possible to adapt this housing according to the thermal forces generated by the battery cells. of accumulators so as to contain these expansion effects due to the cells themselves.

[0076] Thanks to the invention, it is therefore possible to implement a compromise in the production of the housing so as to obtain a certain rigidity while guaranteeing efficient cooling of the cells. Given the thickness characteristics of the rear part of the housing of the accumulator battery module, the heat exchanges between the cooling circuit and the cells are optimized, thus allowing efficient cooling of the accumulator battery module.

[0077] Finally, this implementation makes it possible to reduce the weight of the accumulator battery module, and therefore, advantageously, to reduce its manufacturing cost.

Claims

CLAIMS

1. A storage battery module (30) comprising: - a rear part (32) provided with a bottom wall (32A), intended to be placed in contact with a cooling circuit (27), and with an edge (32B) running along the bottom wall (32A), the bottom wall (32A) having a thickness of less than 3 millimeters, and - a front part (34) comprising a front wall (34A) bordered by a side wall (34B), said side wall (34B) extending towards the edge (32B) of the rear part (32), the front part (34) delimiting with the rear part (32) a housing for receiving a plurality of accumulator cells (35), the front part (34) and the rear part (32) being assembled by grooving said edge (32B) of the rear part (32) and the side wall (34B) of the front part (34).

2. A battery module (30) according to claim 1, wherein the edge (32B) has a height of less than 10 millimeters.

3. A battery module (30) according to claim 1 or 2, wherein the grooving comprises joining the edge (32B) of the rear portion (32) and the side wall (34B) of the front portion (34) by laser welding.

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

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

6. A battery module (30) according to any one of claims 1 to 5, wherein said border (32B) is interrupted at corners.

7. A battery module (30) according to claim 6, wherein the side wall (34B) of the front portion (34) has, at its corners, fixing elements (34C) to a receiving support (20) of a motor vehicle (1), said fixing elements (34C) being positioned opposite the interrupted corners of the edge (32B) of the rear part (32).

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

9. An accumulator battery module assembly (10) according to claim 8 taken in dependence on claim 7, wherein the receiving support (20) comprises fixing means (22A) for said accumulator battery module (30), said fixing means (22A) being intended to cooperate with the fixing elements (34C) of the side wall (34B) of the front part (34) of said accumulator battery module (30).

10. Motor vehicle (1) comprising an accumulator battery module assembly (10) according to claim 8 or 9.

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