Floor for battery module

Abstract

The invention relates to a floor (10) for a battery module comprising several cells (4), the floor (10) comprising a wall (12) and receiving spaces (14) distributed on the wall (12) and intended to receive cells (4), characterized in that in each receiving space (14), the wall (12) has a localized weakening zone (20) forming a flap (15), configured to yield when the pressure (P) exerted on the wall (12) exceeds a threshold (S). The invention also relates to an assembly (1). The invention also relates to a method for implementing the floor (10). Figure 8

Description

Title of the invention: Floor for battery module Technical field

[0001] The present invention relates to a floor for a battery module comprising several cells. The invention also relates to an assembly comprising a battery module, a floor, and glue.

[0002] The field of the invention is that of floors for battery modules, in all sectors of activity, in particular in the automotive sector. Prior art

[0003] An electric battery module may be designed to equip a vehicle, industrial, agricultural, domestic equipment, or any other application.

[0004] In the event of a battery cell malfunction, such as a short circuit, the cell will produce gas and build up pressure. It is imperative to release the pressure to avoid an accident. Statement of the invention

[0005] The aim of the present invention is to provide a vehicle floor which overcomes the above problem.

[0006] For this purpose, the invention relates to a floor for a battery module comprising several cells, the floor comprising a wall and receiving spaces which are distributed over the wall and intended to receive cells, characterized in that in each receiving space, the wall comprises a localized weakening zone forming a cover, configured to yield when the pressure exerted on the wall exceeds a threshold.

[0007] Thus, the invention makes it possible to improve the safety of the battery module. In the event of a malfunction and pressure build-up in a battery cell, the pressure in the cell can be released.

[0008] According to other advantageous characteristics of the floor according to the invention, taken in isolation or in combination:

[0009] - The localized weakening zone comprises a recess formed on one face lower part of the wall.

[0010] - The localized weakening zone has an incipient rupture.

[0011] - In each receiving space, the wall has a cavity sized for retain a predetermined amount of glue.

[0012] - The cavity extends in the wall in an external radial direction up to the initiation of rupture.

[0013] - The wall is substantially flat and has a thickness of between 2 millimeters between the receiving spaces, and 0.5 millimeters in the areas of localized weakening.

[0014] The invention also relates to an assembly comprising: - a battery module comprising several cells; - a floor as described above; and - glue placed between the floor and the cells positioned in the reception areas.

[0015] According to an advantageous embodiment, the cell comprises a lower face provided with a rupture initiation point, which is arranged opposite the localized weakening zone formed on the wall in the receiving space.

[0016] Preferably, in each receiving space, the wall comprises a cavity sized to retain a predetermined quantity of glue. For certain neighboring receiving spaces, at least the following three parameters: - the geometry of the cavities, - the spacing between two neighboring cells, and - the quantity of glue deposited in the cavities, are configured so that the glue rises between two neighboring cells.

[0017] The invention also relates to a method for implementing a floor as described above. The method is characterized in that it comprises the following steps: a) manufacture the floor; b) place glue in the reception areas; c) arrange the cells in the receiving spaces, with the glue interposed between the wall and the cells. (d) once the battery module is in service, in each receiving space provided with a cell:

[0018] - when the pressure exerted on the wall is lower than the threshold, the cover remains in place ; and

[0019] - when the pressure exerted on the wall exceeds the threshold, the seal gives way so that the pressure decreases. Description of the figures

[0020] The invention will be better understood on reading the description which follows, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0021] [Fig. 1] is a perspective view of the floor according to the invention.

[0022] [Fig.2] is a view similar to [Fig.l], on a larger scale, showing a corner of the floor.

[0023] [Fig.3] is a view similar to [Fig.2], with a section passing through two spaces of reception.

[0024] [Fig.4] is another perspective view with a transverse section, showing a assembly according to the invention, comprising the floor and three cells arranged on the floor, the section plane containing the vertical axes of the cells.

[0025] [Fig.5] is a transverse section showing an operculum.

[0026] [Fig.6] is a view similar to [Fig.3], showing the cell and the closed operculum.

[0027] [Fig.7] is a view similar to [Fig.6], showing the cell and the open operculum.

[0028] [Fig.8] is a transverse section showing the cell and the open operculum, as in [Fig.7].

[0029] [Fig.9] is an enlarged view of detail IX in [Fig.4].

[0030] [Fig. 10] is an enlarged view of detail X in [Fig.4]. Detailed description of the invention

[0031] Figures 1 to 8 describe an assembly (1) according to the invention, comprising a battery module (2), a floor (10) designed to support the battery module (2), and glue (6) arranged between the floor (10) and the battery module (2).

[0032] The battery module (2) comprises several cells (4), generally several tens of cells (4).

[0033] The floor (10) comprises a wall (12) and two edges (13) arranged perpendicular to the wall (12). The floor (10) may be made of polymer material, for example polypropylene, loaded or not, or any other material suitable for the intended application.

[0034] The floor (10) comprises receiving spaces (14) distributed over the wall (12) and intended to receive the cells (4). In each receiving space (14), the wall (12) comprises a localized weakening zone (20) forming a cover (15), configured to yield when the pressure (P) exerted on the wall (12) exceeds a threshold (S).

[0035] The cover (15) functions as a mechanical fuse. The pressure (P) threshold (S) is defined as a function of the geometric characteristics of the localized weakening zone (20). In particular, the cover (15) is configured to yield under the pressure (P) of the degassing of a cell (4) stuck to the wall (12) in the space (14), above the cover (15).

[0036] The wall (12) is substantially flat. The wall (12) has a maximum thickness (el2) between the receiving spaces (14) and a minimum thickness in the localized weakening zones (20). As an order of magnitude, the wall (12) may have a thickness (el2) of approximately 2 millimeters between the receiving spaces (14) and approximately 0.5 millimeters in areas of localized weakening (20), depending on the grade of material chosen.

[0037] The localized weakening zone (20) comprises a cylindrical hollow (25) and an annular recess (26), formed on a lower face of the wall (12). The recess (26) is located at the external edge of the hollow (25) and is deeper than the hollow (25). The recess (16) has a rounded bottom on the outside and a truncated cone on the inside. The localized weakening zone (20) also comprises a rupture initiation point (27), which extends according to a cylindrical profile, from the recess (26) on the lower face to the upper face of the wall (12). The rupture initiation point (27) facilitates the detachment of the cover (15) from the rest of the wall (12), when the pressure (P) exceeds the threshold (S).

[0038] In each receiving space (14), the wall (12) comprises a cavity (16) sized to retain a predetermined quantity of glue (6). The cavity (16) extends in the wall (12) in an external radial direction up to the rupture initiation point (27). The cavity (16) has a rounded bottom on the outside and a frustoconical bottom on the inside, on the side of the initiation point (27).

[0039] Each space (14) has a central axis of symmetry (A14). The cover (15), the cavity (16), the zone (20) and its elements (25, 26, 27) are symmetrical with respect to the axis (A14).

[0040] Each cell (4) comprises a cylindrical wall (41), an upper face (42) and a lower face (43), which rests on the floor (10). The lower face (43) comprises a fixed part (44) positioned on the cavity (16) and the glue (6). The lower face (43) also comprises a movable part (45) positioned on the cover (15). A rupture initiation point (46) is formed between the fixed part (44) and the movable part (45). The initiation point (46) is arranged opposite the localized weakening zone (20), more precisely opposite the initiation point (27).

[0041] The method for implementing the floor (10) comprises several successive steps. In a step a), the floor (10) is manufactured, according to one or more suitable techniques. In a step b), the glue (6) is placed in the cavities (16) of the receiving spaces (14), for example by depositing a continuous serpentine bead of glue (6). In a step c), the cells (4) are placed in the receiving spaces (14), with the glue (6) interposed between the wall (12) and the cells (4). The lower faces (43) of the cells (4) crush the bead of glue (6), so that the excess glue (6) is forced into the receiving cavities (16). Thus, a rigid connection is created between the floor (10) and the cell (4). In practice, the method can be modified without departing from the scope of the invention, as defined by the claims.

[0042] Once the battery module (2) is in service, in each receiving space (14) provided with a cell (4): - when the pressure (P) exerted on the wall (12) is lower than the threshold (S), the cover (15) remains in place, as in figures 4, 5, 6, 9 and 10; and - when the pressure (P) exerted on the wall (12) exceeds the threshold (S), the cover (15) gives way so that the pressure decreases, as in figures 7 and 8. The cover (15) generally gives way on one side, and not over its entire circumference.

[0043] As visible in Figures 2 and 9, for certain neighboring reception spaces (14), the glue (6) rises between two neighboring cells (4) and creates a rigid connection between these cells (4), which reinforces the rigidity of the assembly (1). This rise of glue (6) is obtained by optimizing several parameters, in particular the following parameters: - the geometry of the cavities (16),

[0044] - the spacing between two neighboring cells (4), and

[0045] - the quantity of glue (6) deposited in the cavities (16).

[0046] As visible in figures 2 and 10, for other neighboring reception spaces (14), the glue (6) does not create a rigid connection between two neighboring cells (4).

[0047] In practice, the floor (10) described above makes it possible to ensure several advantageous functions: - support the cells (4) of the battery module (2); - guarantee a localized fuse function with the covers (15); - ensure the retention of the glue (6); - optimize the positioning of the glue (6) in relation to the cover (15) and the cell (4).

[0048] The assembly (1), the battery module (2) and the floor (10) may be shaped differently from figures 1 to 10 without departing from the scope of the invention, which is defined by the claims.

[0049] Furthermore, the technical characteristics of the different embodiments and variants mentioned above can be, in whole or in part, combined with each other. Thus, the floor (10) can be adapted in terms of cost, functionality and performance.

Claims

Claims

1. Floor (10) for a battery module (2) comprising several cells (4), the floor (10) comprising a wall (12) and receiving spaces (14) which are distributed over the wall (12) and intended to receive cells (4), characterized in that in each receiving space (14), the wall (12) comprises a localized weakening zone (20) forming a cover (15), configured to yield when the pressure (P) exerted on the wall (12) exceeds a threshold (S).

2. Floor (10) according to claim 1, characterized in that the localized weakening zone (20) comprises a recess (26) formed on a lower face of the wall (12).

3. Floor (10) according to any one of the preceding claims 1 or 2, characterized in that the localized weakening zone (20) comprises an incipient rupture (27).

4. Floor (10) according to any one of the preceding claims 1 to 3, characterized in that in each receiving space (14), the wall (12) comprises a cavity (16) sized to retain a predetermined quantity of glue (6).

5. Floor (10) according to claims 3 and 4 taken in combination, characterized in that the cavity (16) extends in the wall (12) in an external radial direction up to the rupture initiation point (27).

6. Floor (10) according to any one of the preceding claims 1 to 5, characterized in that the wall (12) is substantially flat and has a thickness (el2) of between: - 2 millimeters between the receiving spaces (14), and - 0.5 millimeters in the areas of localized weakening (20).

7. Assembly (1) comprising: - a battery module (2) comprising several cells (4); - a floor (10) according to any one of the preceding claims 1 to 6; and - an adhesive (6) arranged between the floor (10) and the cells (4) positioned in the receiving spaces (14).

8. Assembly (1) according to the preceding claim 7, characterized in that the cell (4) comprises a lower face (43) provided with a rupture initiator (46), which is arranged opposite the zone localized weakening (20) formed on the wall (12) in the receiving space (14).

9. Assembly (1) according to any one of the preceding claims 7 or 8, characterized in that in each receiving space (14), the wall (12) comprises a cavity (16) sized to retain a predetermined quantity of glue (6), and in that for certain neighboring receiving spaces (14), at least the following three parameters: - the geometry of the cavities (16), - the spacing between two neighboring cells (4), and - the quantity of glue (6) deposited in the cavities (16), are configured so that the glue (6) rises between two neighboring cells (4).

10. Method for implementing a floor (10) according to one of the preceding claims 1 to 6, characterized in that it comprises the following steps: a) manufacturing the floor (10); b) placing the glue (6) in the receiving spaces (14); c) placing the cells (4) in the receiving spaces (14), with the glue (6) interposed between the wall (12) and the cells (4). d) once the battery module (2) is in service, in each receiving space (14) provided with a cell (4): - when the pressure (P) exerted on the wall (12) is lower than the threshold (S), the cover (15) remains in place; and - when the pressure (P) exerted on the wall (12) exceeds the threshold (S), the cover (15) gives way so that the pressure (P) decreases.

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