MOUNTING OF TRACTION BATTERIES UNDER VEHICLE COMPATIBLE WITH SIDE IMPACT POST

Abstract

FIXING OF TRACTION BATTERIES UNDER VEHICLE COMPATIBLE WITH SIDE IMPACT POST The invention relates to a motor vehicle structure (4), comprising a floor (6) with two longitudinal edges; two longitudinal profiles (10) extending under the floor (6); two lateral profiles (8) extending along the two longitudinal edges of the floor (6); a box (12) containing electrical energy storage batteries arranged under the floor (6); in which the box (12) is fixed to the two longitudinal profiles (10) by fixing means (22) configured to yield in the event of a side impact of the post type (18). (Figure to be published with the abstract: Figure 4)

Description

Title of the invention: FIXING OF TRACTION BATTERIES UNDER VEHICLE COMPATIBLE WITH SIDE POST IMPACT Technical field

[0001] The invention relates to the field of motor vehicles, more particularly to the field of the structure or body of motor vehicles. Prior art

[0002] The development of electrically powered motor vehicles is experiencing significant growth. For this purpose, it is necessary to place electrical energy storage batteries intended for traction, more commonly called traction batteries, on the structure or body of the vehicle. It is common to place these traction batteries in a central position under the floor of the vehicle structure. However, in the event of an intrusive side impact, such as in the event of a side impact of the pole type, the batteries can be severely damaged.

[0003] In the Euro NCAP pole-type side impact test, a vehicle is propelled sideways at 32 km / h against a rigid, narrow pole. The vehicle is positioned perpendicular to the direction of movement, or as has been the case since 2015, at an angle to the perpendicular. When the vehicle is equipped with a central airbag to prevent front seat occupants from colliding, two average male side impact dummies are placed in the front seats. When there is no central airbag, a single dummy is placed in the driver's seat. This is a very severe test of a vehicle's ability to protect the driver's head. Because the load on the vehicle is localized to such an extent that deformation can be very significant, the pole can penetrate deep into the passenger compartment.

[0004] The published patent document FR 3 069 224A1 addresses this problem and provides the solution of reinforcing the floor crossmembers, more particularly at the outer ends of the crossmembers in question, between the traction batteries and the side rails or rocker panels. This solution allows the structure to have greater resistance to deformation in the event of a side impact of the post type. However, it has the disadvantages of making the vehicle heavier, increasing its production cost and reducing the capacity to absorb the side impact. Statement of the invention

[0005] The invention aims to overcome at least one of the drawbacks of the aforementioned state of the art. More specifically, the invention aims to make a motor vehicle structure equipped with traction batteries compatible with the pole-type side impact test, and to do so in a simple, inexpensive and / or not weighing down the vehicle.

[0006] The invention relates to a motor vehicle structure, comprising a floor with two longitudinal edges; two longitudinal profiles extending under the floor; two lateral profiles extending along the two longitudinal edges of the floor; a box containing electrical energy storage batteries arranged under the floor; remarkable in that the box is fixed to the two longitudinal profiles by fixing means configured to yield in the event of a lateral impact of the post type.

[0007] The fixing means are configured to yield before deformation of the box or at least before deformation of the box likely to damage the electrical energy storage batteries.

[0008] According to an advantageous embodiment of the invention, the fixing means comprise fixing screws.

[0009] According to an advantageous embodiment of the invention, the fixing screws each have a weakening zone capable of breaking in a preferential manner during a lateral impact of the post type.

[0010] According to an advantageous embodiment of the invention, the weakening zone of each fixing screw is a groove adjacent to a head of said fixing screw.

[0011] According to an advantageous embodiment of the invention, the fixing means further comprise transversely opening fixing holes in which the fixing screws engage, respectively, each of said transversely opening fixing holes being capable of allowing sliding followed by disengagement of the corresponding fixing screw during a lateral impact of the post type.

[0012] According to an advantageous embodiment of the invention, the fixing holes opening transversely are formed on the two longitudinal profiles, the opening being directed transversely towards the outside of the motor vehicle.

[0013] According to an advantageous embodiment of the invention, the fixing holes opening transversely are formed on the box, the opening being directed transversely towards the interior of the motor vehicle.

[0014] According to an advantageous embodiment of the invention, the box comprises two side walls and fixing lugs arranged along said two side walls, the fixing holes opening transversely formed on the box being on said fixing lugs.

[0015] According to an advantageous embodiment of the invention, at least one of the transversely opening fixing holes has an opening with an effective width less than the corresponding diameter of the corresponding fixing screw, so that the disengagement of said fixing screw causes a deformation of said transversely opening fixing hole.

[0016] According to an advantageous embodiment of the invention, the fixing means comprise at least one spacer forming at least one of the fixing holes opening transversely.

[0017] Advantageously, each of the at least one spacer is fixed to the box, the outlet being directed transversely towards the interior of the motor vehicle, or to one of the longitudinal profiles, the outlet being directed transversely towards the exterior of the motor vehicle.

[0018] The measures of the invention are advantageous in that they allow the motor vehicle structure to preserve the integrity of the electrical energy storage batteries during a side impact with a post, and this in a simple and inexpensive manner. These measures are also advantageous in that they do not increase the weight of the vehicle. They also have a diversity of implementation, which makes it possible to cope with different mounting constraints depending on the vehicle model. Indeed, depending on the configuration of the longitudinal profiles and the box, the fixing means capable of yielding in the event of a side impact of the post type can be selected optimally from a manufacturing cost point of view as well as from an efficiency point of view. Brief description of the drawings

[0019] [fig. 1] is a perspective view of the underside of a motor vehicle;

[0020] [fig.2] is a cross-sectional view of the motor vehicle structure of the [fig.l], before impact;

[0021] [fig.3] is a cross-sectional view of the motor vehicle structure of the [fig.l], during impact, without the measures of the invention;

[0022] [fig.4] is a cross-sectional view of the motor vehicle structure of the [fig.l], during impact, with the measurements of the invention;

[0023] [fig.5] is a perspective view of a fixing lug, allowing fixing of the traction battery box according to a first embodiment of the invention;

[0024] [fig.6] is a perspective view of a longitudinal profile under the floor of the motor vehicle structure, allowing attachment of the traction battery box according to a second embodiment of the invention;

[0025] [fig.7] is a cross-sectional view of the motor vehicle structure, illustrating a fixing of the traction battery box according to a third embodiment of the invention;

[0026] [fig.8] is a cross-sectional view of the motor vehicle structure, illustrating a fixing of the traction battery box according to a fourth embodiment of the invention;

[0027] [fig.9] illustrates two examples of spacer for fixing the [fig.8] according to the fourth embodiment of the invention; Detailed description

[0028] [fig.l] illustrates in perspective a motor vehicle 2, more particularly its structure 4 comprising a floor 6, two longitudinal profiles 10 extending under the floor, commonly called stretchers, and two lateral profiles 8 extending along the two longitudinal edges of the floor 6, more commonly called lateral side members or rocker panels. This is a conventional structure, in itself well known to those skilled in the art.

[0029] The motor vehicle structure 4 illustrated in [fig. 1] has the particularity of comprising a box 12 containing electrical energy storage batteries, arranged under the floor 6. The box 12 comprises in particular two side walls 12.1 and fixing lugs 12.2 distributed along the two side walls, ensuring fixing between the side walls 12.1 in question and the two longitudinal profiles 10 extending under the floor 6, commonly called stretchers.

[0030] [Fig. 2] is a cross-sectional view of one of the two lateral sides of the motor vehicle structure 4 of [Fig. 1], before impact. It is understood that the motor vehicle structure is generally symmetrical, with the exception of course of a few elements which are not the subject of the present invention and are not shown, so that the left and right sides are generally identical by symmetry. One can observe the floor 6, generally flat although comprising stiffening ribs or bosses, the lateral profile 8 fixed to the longitudinal edge of the floor 6, below said floor, and the longitudinal profile 10 directly under the floor 6 and at a distance, transversely or laterally, from the lateral profile 8. The box 12 containing the electrical energy accumulator modules, not shown, is arranged under the floor 6, with the side wall 12.1 located in line with the longitudinal profile 10.The fixing lug 12.2 visible in [fig.2] extends vertically along an outer face of the side wall 12.1 to the longitudinal profile 10. More specifically, the fixing lug 12.2 comprises a lateral face, generally vertical, arranged against the side wall 12.1 of the box 12 and an upper face, generally horizontal, fixed against a lower face of the longitudinal profile 10. A connecting piece 14 can ensure the fixing between the floor 6 and the lateral profile 8, the connecting piece 14 forming a lateral extension of the floor 6, with a vertical portion allowing fixing to the lateral profile 8 at a height lower than that of the floor 6. A reinforcement 16 can be provided between the lateral profile 8 and the longitudinal profile 10, this reinforcement being intended to work essentially in tension or compression in a direction generally transverse to the vehicle.Post 18 of the Euro NCAP post type side impact test mentioned above is shown adjacent to side profile 8. In the test in question, the . motor vehicle with its structure 4 is moved in a transverse direction towards the post 18 in question which is fixed. This movement corresponds to a relative movement of the post 18 with respect to the structure in the direction indicated by the arrow.

[0031] [Fig. 3] corresponds to [Fig. 2], however no longer before the impact but during the impact. It can be observed that the driving of the post 18 into the motor vehicle structure 4 tends to deform the floor 6 in compression in the plane of said floor, as illustrated by the straight arrow. This movement is accompanied by a movement of the side wall 12.1 of the box, causing a collision with the batteries or electrical energy storage modules 20, likely to damage them. The inventors of this invention have found that the driving of the post 18 into the motor vehicle structure 4 also tends to pivot the floor, as illustrated by the curved arrow. They then discovered that a release of the fixing between the box 12 and the longitudinal profile would allow the floor 6 to deform without interfering with the electrical energy storage batteries 20.

[0032] [fig.4] corresponds to [fig.3] with the difference that the means 22 for fixing the box 12 to the longitudinal profile 10 are configured to give way in the event of a lateral impact of the post type. It can in fact be observed in [fig.4] that once these means of fixing 22 have given way, the floor 6 as well as the elements connecting the floor 6 to the lateral profile 8 can deform without interfering with the box 12, more particularly with the electrical energy storage batteries 20.

[0033] The means 22 for fixing the box 12 to the longitudinal profiles 10, capable of yielding in the event of a lateral impact of the post type, can be implemented in several and various ways.

[0034] Figures 5 to 9 illustrate four embodiments of such fixing means, it being understood, however, that these different embodiments can be combined with each other or with other non-detailed embodiments.

[0035] [fig.5] illustrates a first embodiment of the fixing means 22, these comprising at least one fixing screw 22.1 cooperating with the longitudinal profile 10 ([fig.4]) and with a hole 22.2 formed in the fixing lug 12.2. The fixing hole 22.2 is particular in that it opens transversely, that is to say allows disengagement of the fixing screw 22.1 after sliding thereof relative to the fixing hole 22.2. More specifically, the sliding of the fixing screw 22.1 along the fixing hole 22.2 disengages the head (not shown) and the barrel of the screw from the fixing lug 12.2 and separates the latter from the longitudinal profile 10 ([fig.4]).

[0036] In this case, the fixing lug 12.2 is a stamped sheet with a horizontal portion 12.2.1 intended to be placed against the longitudinal profile 10 ([fig.4]), and a vertical portion 12.2.2 intended to be placed against the side wall 12.1 of the box 12 ([fig.4]). In this case, the fixing hole 22.2 is formed through the horizontal portion 12.2.1, the fixing hole 22.2 opening through the vertical portion 12.2.2, at an area adjacent to the fold of the sheet between the horizontal 12.2.1 and vertical 12.2.2 portions. It is however understood that the fixing hole 22.2 could open onto the horizontal portion 12.2.1 provided that the latter has a sufficient extent.

[0037] The direction in which the fixing hole 22.2 opens is represented by the arrow starting from the fixing screw 22.1 in [fig.5]. This direction is directed towards the inside of the vehicle so as to allow sliding followed by disengagement of the fixing screw 22.1 during transverse compression of the motor vehicle structure, more particularly of the floor and the side profile during a side impact of the post type, as illustrated in [fig.4].

[0038] It can be observed that the fixing lug 12.2 shown in [fig.5] has two fixing holes opening transversely 22.2, it being understood that their number can be one, two, three or even more.

[0039] [Fig. 6] illustrates a second embodiment of the fixing means 22, these comprising at least one fixing screw 22.1 cooperating with the box 12, for example one of the fixing lugs 12.2 of said box 12, and with a transversely opening fixing hole 22.3 formed in the longitudinal profile 10. It is therefore in some way an inversion of the first embodiment illustrated in [Fig. 5]. The direction in which the fixing hole 22.3 is opening is represented by the arrow in [Fig. 6]. This direction is directed towards the outside of the vehicle so as to allow sliding followed by disengagement of the fixing screw 22.1 during transverse compression of the motor vehicle structure, more particularly of the floor and the lateral profile during a lateral impact of the post type, as illustrated in [Fig. 4]. It is therefore opposite to the direction in which the fixing hole 22.2 of the first embodiment in [fig.5] opens out.

[0040] [fig.7] illustrates a third embodiment of the fixing means 22, these comprising at least one fixing screw 22.1 cooperating with the box 12, for example one of the fixing lugs 12.2 of said box 12, and with the longitudinal profile 10. The fixing screw 22.1 is particular in that it has a weakening zone 22.1.4 capable of breaking in a preferential manner during a lateral impact of the post type. This weakening zone 22.1.4 is in this case formed by a circular groove or groove adjacent to the head 22.1.1 of the fixing screw 22.1. The fixing screw 22.1 may conventionally and successively comprise, along the main direction of said screw, a screw head 22.1.1, a barrel 22.1.2 and a thread 22.1.3. The weakening zone 22.1.4 is advantageously formed at the level of the barrel 22.1.2, at a position directly adjacent to the screw head 22.1.1.

[0041] With reference to [fig.4], during the lateral impact of the post type, the deformation in compression and possibly in pivoting of the floor 6 generates at the level of the fixing screw(s) 22.1 of the fixing means 22 between the box 12 and the longitudinal profile 10 shear forces added to possible tensile and / or bending forces. These forces will then generate maximum stresses at the level of the weakening zone 22.1.4 which will exceed the breaking stress of the material of the fixing screw 22.1 and cause it to break.

[0042] It is understood that the weakening of the fixing screw 22.1 may take other forms than the circular groove illustrated in [fig.7].

[0043] Figures 8 and 9 illustrate a fourth embodiment of the fixing means 22, these comprising a spacer 22.4 or 122.4 fixed to the box 12, for example to one of the fixing lugs 12.2 of said box 12, or to the longitudinal profile 10, and at least one fixing screw 22.1 engaging with the spacer 22.4 or 122.4 and the other of the box 12 and the longitudinal profile 10.

[0044] With reference to [fig.9], the spacer 22.4 may comprise a transversely opening fixing hole 22.2 or 22.3, similarly to the first and second embodiments illustrated in figures 5 and 6. The operating principle is then similar to that of these embodiments, namely that the sliding capacity of the fixing screw 22.1 until disengagement, during the lateral impact of the post type, will be predominantly dependent on the initial tightening achieved by the fixing screw 22.1, namely the friction forces at the level of the fixing. The opening of the fixing hole 22.2 is advantageously directed transversely towards the interior of the motor vehicle when the spacer 22.4 is fixed to the box. The opening of the fixing hole 22.3 is advantageously directed transversely towards the outside of the motor vehicle when the spacer 22.4 is fixed to one of the longitudinal profiles 10.

[0045] Still with reference to [fig.9], the spacer 122.4 may comprise a transversely opening fixing hole 122.2 or 122.3 with a passage section smaller than that of the fixing screw. The sliding capacity of the fixing screw 22.1 until disengagement, during the lateral impact of the post type, will then be dependent not only on the initial tightening achieved by the fixing screw 22.1, namely the friction forces at the level of the fixing, but also by the deformation capacity of the spacer at the level of the reduced passage section. This configuration of the spacer 122.4 allows the fixing means between the box 12 and the longitudinal profile 10 to absorb more of the energy of the lateral impact of the post type before yielding and separating the box from said longitudinal profile. Similarly, the opening of the fixing hole 122.2 is advantageously directed transversely towards the interior of the motor vehicle when the spacer 122.4 is fixed. to the box 12. The opening of the fixing hole 122.3 is advantageously directed transversely towards the outside of the motor vehicle when the spacer 122.4 is fixed to one of the longitudinal profiles 10.

[0046] The spacers 22.4 and 122.4 advantageously have a thickness greater than that of the sheets constituting the longitudinal profile 10 and the box 12, for example greater than 4 mm and / or less than 10 mm. The material may be steel or aluminum. The latter is particularly advantageous for the spacer 122.4 whose transversely opening fixing hole 122.2 or 122.3 has a passage section smaller than that of the fixing screw 22.1, because it has a greater work hardening capacity.

[0047] It is understood that the four embodiments which have just been described can be combined with each other. For example, the first and second embodiments can be combined alternately, that is to say with fixing holes opening transversely onto the box for certain fixing screws and onto the longitudinal profile for other fixing screws. Also for example, the fixing screws with the capacity to break in a preferential manner during a lateral impact of the post type can be implemented with each of the first, second and fourth embodiments.

Claims

Claims

1. Motor vehicle structure (4), comprising: - a floor (6) with two longitudinal edges; - two longitudinal profiles (10) extending under the floor (6); - two lateral profiles (8) extending along the two longitudinal edges of the floor (6); - a box (12) containing electrical energy storage batteries arranged under the floor (6); characterized in that the box (12) is fixed to the two longitudinal profiles (10) by fixing means (22) configured to yield in the event of a lateral impact of the pole type.

2. Motor vehicle structure (4), according to claim 1, in which the fixing means (22) comprise fixing screws (22.1).

3. Motor vehicle structure (4), according to claim 2, in which the fixing screws (22.1) each have a weakening zone (22.1.4) capable of breaking in a preferential manner during a side impact of the post type.

4. A motor vehicle structure (4) according to claim 3, wherein the weakened area (22.1.4) of each of the fixing screws (22.1) is a groove adjacent to a head (22.1.1) of said fixing screw.

5. Motor vehicle structure (4), according to one of claims 2 to 4, in which the fixing means (22) further comprise transversely opening fixing holes (22.2, 22.3; 122.2, 122.3) in which the fixing screws (22.1) engage, respectively, each of said transversely opening fixing holes (22.2, 22.3; 122.2, 122.3) being capable of allowing sliding followed by disengagement of the corresponding fixing screw (22.1) during a side impact of the post type.

6. Motor vehicle structure (4) according to claim 5, wherein the transversely opening fixing holes (22.3) are formed on the two longitudinal profiles (10), the opening being directed transversely towards the outside of the motor vehicle.

7. Motor vehicle structure (4), according to one of claims 5 and 6, in which the transversely opening fixing holes (22.2) are formed on the box (12), the outlet being directed transversely towards the interior of the motor vehicle.

8. Motor vehicle structure (4), according to claim 7, in which the box (12) comprises two side walls (12.1) and fixing lugs (12.2) arranged along said two side walls, the fixing holes opening transversely (22.2) formed on the box being on said fixing lugs (12.2).

9. Motor vehicle structure (4), according to one of claims 5 to 8, in which at least one of the transversely opening fixing holes (22.1; 122.2; 122.3) has an opening with an effective width less than the corresponding diameter of the corresponding fixing screw, so that the disengagement of said fixing screw causes a deformation of said transversely opening fixing hole.

10. Motor vehicle structure (4), according to one of claims 5 to 9, in which the fixing means (22) comprise at least one spacer (22.4; 122.4) forming at least one of the fixing holes opening transversely (22.2, 22.3; 122.2, 122.3).

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