CN115551730A - Lateral reinforcement for a motor vehicle floor equipped with a traction battery - Google Patents

Abstract

The invention relates to a motor vehicle (101) of the electric traction type, comprising: a base plate; a tray (105) for an electric traction electric energy accumulator battery (107), said tray being integrated in said floor; two underbody longitudinal beams (109) on either side of the floor; and at least one lateral reinforcement (111) arranged between the tray (105) and one of the two underbody longitudinal beams (109); the at least one lateral stiffener (111) comprises: a flat structure (113) having an inner edge (113B) adjacent to the tray (105) at the level of the bottom (105B) of the tray (105) and an outer edge (113C) adjacent to a corresponding lower longitudinal beam (109) of the vehicle body; and at least one impact-absorbing element (121) which is fixed to the upper surface of the flat structure (113).

Description

Lateral reinforcement for a motor vehicle floor equipped with a traction battery

Technical Field

The present invention claims priority from french application N ° 2004639 filed on 12.5.2020, the contents of which (text, drawings and claims) are incorporated herein by reference.

The present invention relates to the field of motor vehicles, and more particularly to structural members for motor vehicles of the electric traction type.

Background

The motor vehicle comprises at least one floor panel and two underbody longitudinal beams, which are positioned on either side of the floor panel. In the case of electric traction vehicles, it is common to integrate an electrical energy storage battery pack below the floor of the vehicle and between the underbody longitudinal beams. A lateral reinforcement is also positioned between each beam and the battery pack so as to laterally protect the battery pack from impact.

Rather, utility vehicles have a greater material loading capacity at the rear of the vehicle, and these vehicles are thus designed to be heavier. At present, mainly for ecological reasons, individuals or businesses are increasingly turning to utility vehicles of the electric traction type (either 100% electric or hybrid). The presence of the battery pack causes an increase in the mass of the vehicle.

In addition, strict standards are set up to determine the damage caused by a collision to a newly manufactured vehicle (more specifically, to the occupants of said vehicle). In the event of a side-to-side rod collision, a stronger energy is accumulated on a smaller area, which results in a larger deformation in the structural members of the vehicle. The additional mass of an electric traction utility vehicle can cause greater damage, especially when a collision occurs at the battery pack location. Indeed, the intrusion of the rod into the vehicle may cause impacts between the modules constituting the battery pack, causing leaks and even fires. In this case, the above-mentioned lateral reinforcement is not sufficient to ensure effective protection of the battery pack, wherein the underbody needs to be reinforced to such a level as to avoid damage.

Fig. 1 shows a bottom view of a utility vehicle of the electric traction type, such as found in the prior art, after a side-to-side rod collision.

The utility vehicle 1 comprises a floor panel 3 and at least one tray 5 for an electric energy storage battery pack 7 of the electric traction vehicle 1. The tray 5 of the battery pack 7 is integrated at the bottom plate 3. Furthermore, the vehicle 1 comprises two underbody longitudinal beams 9, which are positioned on either side of the floor panel 3. Finally, one or more lateral stiffeners 11 are positioned between each of the beams 9 and the tray 5 of the battery pack 7.

In the event of a side-to-side pole collision C at the location of the central battery pack 7 of the utility vehicle 1, the impacted underbody longitudinal beam 9 collapses into the vehicle 1, which manifests itself in a collapse of the tray 5 and in a damage of one or more modules (said modules not being shown on the drawing) constituting the battery pack 7. This damage causes a loss of function of the vehicle 1, even when the damage caused is large, causing a fire. In particular, the module located in the vicinity of the collision C is more strongly impacted.

Published patent document FR3063458A1 discloses a side impactor for an electric energy accumulator battery adapted to a hybrid or electric vehicle. The side impactor is positioned between one of the underbody longitudinal beams and the battery pack so as to improve the resistance of the beam against side-rail impacts. The impactor is also formed from a single block of material that forms a rigid foam. However, these impactors have a limited kinetic energy absorption capacity and are therefore not suitable for electric traction-type utility vehicles, which are heavier and cause greater damage during a collision due to their greater kinetic energy.

Published patent document DE102013008428B4 describes a tray for an electric energy accumulator battery of a motor vehicle of the electric traction type and two longitudinal beams on either side of the tray. A shock absorber is positioned continuously at each of the sides of the tray and between the tray and an adjacent longitudinal beam. Each absorber has an energy absorption capacity characteristic variable according to the degree of compression deformation, with the aim of improving the resistance against impacts with lateral rods. These absorbers are however more complex to construct and may therefore be costly.

Disclosure of Invention

The object of the present invention is to overcome at least one of the drawbacks of the prior art described above. More specifically, the object of the invention is to reduce the risk of deterioration of the battery pack of an electric traction vehicle during a side rod collision.

The present invention aims to provide a motor vehicle of the electric traction type, comprising: a base plate; a tray for an electric traction electric energy storage battery pack, the tray being integrated in the floor; two lower body longitudinal beams located on either side of the floor; and at least one lateral reinforcement arranged between the tray and one of the two underbody longitudinal beams; characterized in that said at least one lateral reinforcement comprises: a flat structure having an inner edge adjacent to the tray at the level of the bottom of the tray and an outer edge adjacent to a corresponding lower body longitudinal beam; and at least one impact-absorbing element fixed on the upper surface of the flat structure.

According to an advantageous embodiment of the invention, the flat structural element comprises ribs and/or stiffening chambers extending transversely with respect to the vehicle.

According to an advantageous embodiment of the invention, the flat structure comprises a first plate having a transverse undulation with respect to the transverse direction of the vehicle and a second plate superposed and fixed on the first plate so as to form a transverse reinforcement chamber.

According to an advantageous embodiment of the invention, the at least one lateral reinforcement further comprises a fixing pin extending from the inner edge of the flat structural element transversely with respect to the vehicle and engaging the tray.

According to an advantageous embodiment of the invention, each of said pins is engaged in one of said reinforcement cavities.

According to an advantageous embodiment of the invention, each of said pins is engaged in a reinforcement chamber of the bottom of said tray.

According to an advantageous embodiment of the invention, the at least one crash absorption element comprises a deformable box adjacent to the corresponding underbody longitudinal beam.

According to an advantageous embodiment of the invention, the deformable box comprises a stamping in the shape of a U having a web and two base plates, one of which rests against the flat structural element and the web rests against the corresponding lower longitudinal beam of the vehicle body, and at least one transverse bulkhead, transverse to the vehicle, which couples the two base plates.

According to an advantageous embodiment of the invention, said at least one impact-absorbing element further comprises a block made of porous material, said block being adjacent to said deformable box.

According to an advantageous embodiment of the invention, the at least one impact absorbing element further comprises an elbow (squerre) at the inner edge of the flat structure, the elbow having a first flap fixed against the flat structure and a second flap fixed against the lateral wall of the tray.

Preferably, said lateral stiffeners have a length comprised between 300mm and 400 mm. Advantageously, the material used for the different constituent elements of the reinforcement is a foam made of a polymeric material (for example polyurethane) having a density of at least 100g/L, preferably at least 120g/L, more preferably at most 150g/L, and a metallic material (for example steel) having a thickness of between 0.5mm and 3.5mm, both for the flat structure and for the deformable box.

The measures of the invention are advantageous in that they enable the risk of deterioration of the battery pack of an electric traction motor vehicle (more specifically, an electric traction utility vehicle) following a side-bar collision to be reduced. This improvement is carried out by adding at least one lateral reinforcement between each of said underbody longitudinal beams and the tray of said electric energy battery cell stack. The addition of the reinforcing member can limit the intrusion of the rod into the tray of the battery pack, and therefore can avoid the deterioration of the modules constituting the battery pack even in the event of a severe collision. The presence of the impact-absorbing element enables an improved force damping at the tray position of the battery pack. Furthermore, the lateral reinforcement is able to balance the forces from the start of the impact by improving the transmission of the forces towards the bottom of the tray of the battery pack, in particular due to the presence of the fixing pins. The lateral reinforcement can also improve the energy absorption and cushion the impact of a collision against the tray of the battery pack by avoiding contact between different modules constituting the battery pack. The presence of the elbow consisting of a metal angle groove enables to improve the overall rigidity of the reinforcement. Finally, the installation and the manufacture of the stiffener according to the invention are carried out by techniques known to those skilled in the art, using materials also known and mastered by those skilled in the art. Finally, the addition of such a reinforcement does not significantly increase the overall mass of the vehicle.

Drawings

Other features and advantages of the present invention will become more apparent upon reading the detailed description of the invention and the accompanying drawings in which:

FIG. 1 is a bottom view of a prior art electric traction utility vehicle after a side-to-side pole collision;

FIG. 2 is an exploded view of a lateral reinforcement according to the present invention;

FIG. 3 is an exploded view of the flat structural member and deformable box of the lateral reinforcement member of FIG. 2;

FIG. 4 is a bottom view of the lateral reinforcement of FIGS. 2 and 3 assembled on a vehicle;

FIG. 5 is a perspective view of an alternative embodiment of the lateral reinforcement embodiment shown in FIGS. 2-4;

FIG. 6 is a schematic view of an alternative embodiment of the lateral reinforcement of FIG. 5;

fig. 7 is a bottom view of a motor vehicle having a reinforcement according to the present invention after a side-to-side rod impact.

Detailed Description

The examples described below are given by way of illustration, but other applications or embodiments not described in the present invention are contemplated. Arrow x indicates the normal moving (forward traveling) direction of the vehicle. The arrow y indicates the width of the vehicle from left to right. The arrow z indicates the height of the vehicle from the bottom to the top.

Fig. 1 has been described in the "prior art" section.

Fig. 2-7 repeat the numbering of fig. 1 for the same or similar elements, but with 100 added to the numbering. Reference is additionally made to the description of these prior art related elements.

Fig. 2 and 3 show exploded views of a part of a lateral reinforcement (fig. 2) or a reinforcement according to the invention (fig. 3).

The lateral reinforcement 111 according to the invention comprises a flat structure 113 made up of at least a first plate 115 and a second plate 117. The first plate 115 comprises a transverse relief 115A transverse (and therefore oriented in the y-direction) with respect to the vehicle (which is not shown in fig. 2 and 3). Ribs may also be implemented on the sheet 115 (the alternative embodiment of the invention is not shown on the figures). The second panel 117 is planar and may include a rolled pattern (gaufrege). In fig. 2, it can be observed that the second plate 117 is superimposed and fixed on the first plate 115, thus forming a reinforcement chamber 119 with respect to the transverse direction of the vehicle. Generally, the flat structure 113 may include ribs and/or transverse stiffening cavities 119. The flat structure 113 is preferably made of a metallic material, more preferably steel. Advantageously, each of the plates (115, 117) has a thickness comprised between 1mm and 2 mm. The plates (115, 117) are preferably stamped or, in the case of the first plate 115 only, bent.

Said lateral reinforcement 111 also comprises at least one impact-absorbing element 121 fixed to the upper face 113A of the flat structure 113 and therefore more specifically to the second blade 117 of the flat structure 113.

The impact-absorbing element 121 comprises a deformable box 123, which is itself formed by a stamping 125 in the shape of a U. The stamping 125 includes a web 125A and two substrates, an upper substrate 125B and a lower substrate 125C, the lower substrate 125C being in contact with the flat structure 113. Advantageously, the lower base plate 125C has a central groove so that the base plate 125C forms two lateral tongues (125c.1, 125c.2). The deformable box 123 also comprises at least one transverse partition 127 transverse to the vehicle.

Advantageously, the deformable box 123 comprises two transverse partitions 127 which couple simultaneously the upper base 125B, the lower base 125C and the web 125A of the stamping 125. Advantageously, each of the transverse partitions 127 is fixed at one of the tongues (125c.1, 125c.2) of the lower base plate 125C of the stamping 125. Advantageously, each transverse partition 127 comprises a fixing portion 127A for fixing with the punch 125. Preferably, said deformable box 123 is positioned partially outside said flat structure 113, so that at most 40% of said deformable box 123 is positioned beyond said flat structure 113. Advantageously, said deformable box 123 is preferably made of a metallic material, more preferably steel. Advantageously, the thickness of said stamping 125 is between 0.5mm and 1.5mm, said fixing being preferably carried out by welding or by means of fixing elements (not shown on these figures).

The impact absorbing element 121 further comprises a block 129 made of porous material, which is adjacent to the deformable box 123. The block 129 is preferably made of polyurethane foam, having a density of at least 100g/L, preferably at least 120g/L, and even more preferably having a maximum density of 150g/L, in order to obtain an absorbing and cushioning effect. The block is advantageously positioned on the upper surface 113A of the flat structural member 113. The block extends over the entire width of said structural member 113 and over a length of between 40% and 70% of the length of the structural member 113. This block 129 made of porous material advantageously comprises a first portion 129A having a height similar to that of said deformable box 123 and a second portion 129B, located opposite said deformable box 123 and inside said first portion 129A, said second portion 129B having a height and a length smaller than those of said first portion 129A.

The impact absorbing element 121 further comprises an elbow 131 which is positioned on the inner edge 113B of the flat structure 113. The elbow 131 comprises a first wing 131A fixed to the flat structure 113 and more specifically to the second plate 117 of the flat structure 113. Furthermore, said elbow 131 comprises a second wing 131B perpendicular to the first wing 131A, said elbow 131 being positioned on the side of the second portion 129B of the block 129 made of porous material.

The impact absorbing element 121 further comprises an additional elbow 133 having a first wing 133A fixed with the flat structure 113 and positioned below a block 129 made of cellular material and a second wing 133B extending between the block 129 and the adjacent deformable box 123. The two elbows (131, 133) are intended to reinforce the reinforcement 111 to enable good transmission of forces after a collision. The elbows (131, 133) are preferably made of a metallic material, such as steel. The elbow 131 is advantageously embodied with a thickness of between 2.5mm and 3.5mm, and the additional elbow 133 is embodied with a thickness of between 1mm and 2 mm.

Fig. 4 shows a perspective view of a lateral reinforcement according to the invention fitted in the vehicle.

On which a vehicle 101 is partially shown. A tray 105 (shown in dashed lines) of the electrical energy storage cell stack 107 and more specifically lateral walls 105A and a bottom 105B of said tray 105 are visible on this figure. One of the longitudinal beams 109 (here, the left longitudinal beam 109) is also partially shown in dashed lines in order to be able to observe the assembly of the lateral reinforcement 111 on the vehicle 101.

The inner edge 113B of the flat structure 113 of the lateral reinforcement 111 is arranged adjacent to the tray 105 of the battery pack 107, and more specifically at the level of the bottom 105B of the tray 105. The bottom 105B also has a strengthening chamber 105b.1. The flat structural member 113 also includes an outer edge 113C adjacent to the corresponding underbody longitudinal beam 109.

Advantageously, the deformable box 123 is adjacent to the left longitudinal beam 109 and preferably the web 125A of the stamping 125 of the deformable box 123 is preferably positioned against the beam 109. The underbody longitudinal beam 109 includes a section having a horizontal U-shaped cross section having a vertical wall 109A and two walls of an upper wall 109B and a lower wall 109C. More preferably, said deformable box 123 is partially inserted in the section of the longitudinal beam 109 with lying U-shaped cross section over at least 20% of the length of the longitudinal beam. Thus, the web 125A of the stamping 125 is positioned against the vertical wall 109A of the longitudinal beam 109, and the outer edge 113C of the flat structural member 113 is proximate to the lower wall 109C of the beam 109. Furthermore, the second wing 131B of the elbow 131 is fixed against the lateral wall 105A of the tray 105.

Fig. 5 and 6 show an alternative embodiment of a lateral reinforcement embodiment according to the invention.

According to this alternative embodiment, the lateral reinforcement 111 comprises a fixing pin 135 extending from the inner edge 113B of the flat structure 113 transversely with respect to the vehicle (not visible in fig. 5 and 6), the pin 135 engaging with the tray 105 of the battery pack (not visible in fig. 5 and 6). Preferably, each pin 135 engages in one of the stiffening chambers 119 of the flat structure 113 and in one of the stiffening chambers 105b.1 of the bottom 105B of the tray 105. The pins 135 may have different shapes, such as a cylindrical shape or a parallelepiped shape. Advantageously, the pin 135 is welded to the flat structure 113 by means of a weld 135A.

Fig. 7 shows a bottom view of a motor vehicle with a lateral reinforcement according to the invention after a lateral rod impact. Fig. 7 is described with reference to fig. 2 to 6.

A side-stick collision C occurs at the battery pack 107 location of the vehicle 101. Said rods collapse the floor 103 and the corresponding underbody longitudinal beam 109, said beam 109 thus being in contact with the longitudinal reinforcement 111 according to the invention described above. During the impact C, the flat structural part 113 of the reinforcement 111 is first able to transmit a force towards the bottom 105B of the tray 105 of the battery pack 107. The presence of the retaining pin 135 can assist in the transmission of the force. Next, the impact absorbing element 121 collapses in order to absorb and cushion the impact. Thus, the deformable box 123 first absorbs the impact C by virtue of the deformation of the metal elements (and therefore of the stampings 125, the transverse partitions 127 and the flat structure 113). Then, next, the block 129 made of a porous material buffers the collision. Note that on this figure (not visible on this figure), the rods do not damage the tray 105 of the battery pack 107, in particular the module located in the central battery pack 107 of the vehicle 101 directly involved by the impact. The excitation energy caused by the collision on the module is thus reduced by 75% with respect to the energy generated on a vehicle as shown in fig. 1 which does not comprise a lateral reinforcement 111 according to the invention.

Normally, the different constituent elements of said lateral reinforcement 111 are fixed together by welding, by gluing or by means of fixing elements (not shown on these figures). Of course, said lateral reinforcements 111 may be present as a plurality of examples in the same vehicle 101 at different positions between each of the longitudinal beams 109 and the tray 105 of the battery pack 107.

Claims (10)

1. An electric traction motor vehicle (101) comprising:

-a bottom plate (103);

-a tray (105) for an electric energy accumulator battery (107) for electric traction, said tray being integrated in said floor (103);

-two underbody longitudinal beams (109) on either side of the floor (103); and

-at least one lateral reinforcement (111) arranged between the tray (105) and one of the two underbody longitudinal beams (109);

characterized in that said at least one lateral reinforcement (111) comprises:

-a flat structure (113) having an inner edge (113B) adjacent to the tray (105) at the level of the bottom (105B) of the tray (105) and an outer edge (113C) adjacent to a corresponding lower longitudinal beam (109) of the vehicle body; and

-at least one impact absorbing element (121) fixed on the upper surface (113A) of the flat structure (113).

2. -a motor vehicle (101) according to claim 1; characterized in that said flat structure (113) comprises ribs and/or stiffening chambers (119) extending transversely with respect to said motor vehicle (101).

3. -a motor vehicle (101) according to claim 2; characterized in that said flat structure (113) comprises a first sheet (115) having a transverse undulation (115A) with respect to the motor vehicle (101) and a second sheet (117) superposed and fixed on said first sheet (115) so as to form a transverse reinforcement chamber (119).

4. -a motor vehicle (101) according to any of claims 1 to 3; characterized in that said at least one lateral reinforcement (111) further comprises a fixing pin (135) extending from an inner edge (113B) of said flat structure (113) transversely with respect to said motor vehicle (101) and engaging with said tray (105).

5. -a motor vehicle (101) according to claim 2 or 3 and according to claim 4; characterized in that each of the securing pins (135) engages in one of the reinforcement cavities (119).

6. -a motor vehicle (101) according to claim 4 or 5; characterized in that each of the securing pins (135) engages in a reinforcement chamber (105b.1) of the bottom (105B) of the tray (105).

7. -a motor vehicle (101) according to any one of claims 1 to 6; characterized in that said at least one impact absorbing element (121) comprises a deformable box (123) adjacent to the corresponding underbody longitudinal beam (109).

8. -a motor vehicle (101) according to claim 7; characterized in that said deformable box (123) comprises a stamping (125) in the shape of a U having a web (125A) and two base plates (125B, 125C), one of which (125B, 125C) bears against said flat structural element (113) and the web (125A) bears against a corresponding lower longitudinal beam (109), and at least one transverse bulkhead (127) transverse with respect to said motor vehicle (101) which couples said two base plates (125B, 125C).

9. -a motor vehicle (101) according to claim 7 or 8; characterized in that said at least one impact absorbing element (121) further comprises a block (129) made of porous material, said block being adjacent to said deformable box (123).

10. -a motor vehicle (101) according to any one of claims 1 to 9; characterized in that said at least one impact absorbing element (121) further comprises an elbow (131) at the inner edge (113B) of said flat structure (113), said elbow having a first flap (131A) fixed against said flat structure (113) and a second flap (131B) fixed against a lateral wall (105A) of said tray (105).

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