Electric or hybrid vehicle underbody

Abstract

The underbody (1) for an electric or hybrid motor vehicle comprises: - a hollow side drip edge (2), - a battery conditioning unit (3), and - a load distribution structure (4) including at least one arched element (5) whose legs (6) are oriented towards said conditioning unit and whose arch (7) is oriented away from said conditioning unit; said load distribution structure being located within said side drip edge (2). Figure for the abbreviation: Fig 1

Description

Title of the invention: Underbody for an electric or hybrid motor vehicle. Technical field

[0001] The present invention relates, in general, to electric or hybrid vehicles and, in particular, to the resistance to lateral impacts of the housing for an electric battery housed in the underbody of an electric or hybrid motor vehicle.

[0002] More specifically, the invention relates to an electric or hybrid motor vehicle underbody comprising an elongated force distribution element comprising at least one arched element whose feet are turned towards said conditioning unit, as well as to a motor vehicle incorporating such an underbody. Previous techniques

[0003] In current electric motor vehicles, electrical energy is stored in battery cells housed in a conditioning unit itself located under the floor of the vehicle.

[0004] This packaging unit provides storage for the electrochemical cells that make up the electric battery, generally by grouping them in intermediate packaging called modules. This unit also contributes to protecting the cells against frontal and lateral impacts.

[0005] In a side impact, the electric battery must remain attached to the body and the modules that make up the battery must remain intact to avoid any risk of fire. Such a side impact is the subject of tests and numerical modeling generally referred to as a "pole impact".

[0006] In a known manner, the electric battery conditioning case includes transverse beams, called crossbeams, ensuring its rigidity and resisting the stresses it undergoes.

[0007] The vehicle's mud flaps are further reinforced to form a longitudinal beam which will rest on the cross members during the impact, thus distributing the forces over them and absorbing the energy of the impact by its deformation.

[0008] To increase the amount of energy stored in the conditioning unit, the size of the modules is increased and the spacing between the crossbars is increased. However, the greater the spacing between the crossbars, the less effective the protection will be for the cells located between two successive crossbars.

[0009] To compensate for this reduced protection, one solution is to further reinforce the flashing to increase the stiffness of the beam it forms. However, this leads to an increase in mass.

[0010] Another solution is to add cross members to the floor of the body. However, this is not possible everywhere, particularly under the feet of the vehicle's occupants. Furthermore, this also leads to an increase in mass.

[0011] Furthermore, French patent application 3,078,048 discloses an electric motor vehicle whose structure comprises, on each of its lateral sides, a longitudinal member arranged parallel to an underfloor frame. The vehicle further comprises a battery protection device including arched load-distributing elements arranged between the longitudinal member and the underfloor frame. The protection device in question is designed to distribute the forces received locally following a pole-type impact. Description of the invention

[0012] The invention aims to provide a base for an electric or hybrid motor vehicle having performance for the protection of the electric battery in the event of a "pole impact" at least as good as with the above solutions, while being lighter and having more space to house the battery.

[0013] The invention proposes for this purpose a base for an electric or hybrid motor vehicle comprising: - a hollow side flap, - a housing for an electric battery, and - a load distribution structure comprising at least one arched element whose feet are turned towards said housing and the arch on the opposite side of said housing; characterized in that said load distribution structure is located in said side flap.

[0014] The invention is based on the observation that there is sufficient space inside a hollow flap to house the arched element(s) of a load distribution structure.

[0015] Since the load distribution structure is located in the drip edge, the assembly formed by the drip edge and the load distribution structure is more compact than when the load distribution structure is located elsewhere. The underbody thus offers more space for arranging the battery conditioning unit, making it possible to increase the size of the modules and therefore the amount of energy stored on board.

[0016] Furthermore, due to its inherent stiffness, the load distribution structure increases the stiffness of the flap and therefore its capacity to act as a beam for distributing forces along the conditioning unit. In other words, the load distribution structure forms a reinforcement for the flap. The assembly formed by the flap and the structure the distribution of efforts thus ensures at least as well, or even better, the function of distributing efforts than when they perform it separately.

[0017] Furthermore, the space between the wall of the flashing and the intrados of the arched element allows the latter to flex and thus absorb the impact energy before transmitting it to the flashing wall. In other words, the permissible deflection for the load distribution structure, and therefore the absorbed impact energy, is increased.

[0018] The better distribution and absorption of forces explained above also makes it possible to limit the number of cross members in the conditioning box which is thus in turn lighter and offers more space to arrange the modules of the electric battery.

[0019] According to another feature, said force distribution structure comprises a rigid profiled body having at least one region shaped to give said at least one arched element.

[0020] According to yet another feature, said load distribution structure has the form of a serpentine having alternating first curved segments and second curved segments, said second curved segments having a smaller radius of curvature than said first curved segments, said second curved segments each forming said foot of said arched element, said first curved segments each forming said vault of said arched element.

[0021] In one embodiment, said force distribution structure is honeycomb-shaped, each honeycomb having a generally rectangular cross-section.

[0022] Advantageously, said force distribution structure has two opposing longitudinal faces turned respectively towards said conditioning housing and opposite said conditioning housing, said force distribution structure having at least one longitudinal groove formed in at least one of said longitudinal faces.

[0023] According to yet another characteristic, said load distribution structure comprises a plurality of cross sections placed end to end and / or longitudinal sections placed side by side.

[0024] It can be foreseen that the said force distribution structure is in one piece.

[0025] It can also be provided that, said conditioning box includes crossbars oriented transversely to said side flap, at least one of said feet of said arched element being located in the extension of said crossbar.

[0026] This arrangement allows for even better distribution and absorption of stresses as explained above, thus further limiting the number of cross members in the conditioning unit, which is therefore even lighter and offers even more space for arranging the electric battery modules.

[0027] Advantageously, a plurality of spacers are arranged each in the extension of a said respective cross member, between said flap and said conditioning unit.

[0028] The invention also relates to an electric or hybrid motor vehicle comprising a chassis as defined above. Brief description of the drawings

[0029] Other purposes, advantages and features will become apparent from the following description, given for illustrative purposes only and made with reference to the accompanying drawings on which:

[0030] [Fig-1] is a cross-sectional view along a horizontal plane, taken vertically, of a vehicle underbody according to the invention in a first embodiment, comprising a drip edge and a load distribution structure with arched elements received in the drip edge.

[0031] [Fig.2] is the cross-sectional view along line II-II on [Fig.1], the drip edge being only partially represented.

[0032] [Fig.3] is a view similar to [Fig.2], but in perspective and following another embodiment of the base.

[0033] [Fig.4], [Fig.5], [Fig.6], [Fig.7] and [Fig.8] are views similar to [Fig.1] each following another respective embodiment of the base.

[0034] In the following description, the terms "longitudinal", "transverse", "vertical", "horizontal", "front", "rear", "left", "right", "lower", "upper", "under", "on", "above" and "below" are understood to refer to the usual orthogonal coordinate system for motor vehicles, shown in Figures 1 to 8 and comprising:

[0035] - a longitudinal axis X, horizontal and directed from the front to the rear of the vehicle;

[0036] - a horizontal transverse axis Y, perpendicular to the X axis and directed from the left to the right side of the vehicle moving forward;

[0037] - a Z axis, orthogonal to the X and Y axes and vertical, directed from bottom to top. DETAILED DESCRIPTION

[0038] Figures 1 and 2 illustrate a base 1 for an electric or hybrid motor vehicle (not shown).

[0039] The two parts of the underbody 1 which are respectively located on either side of a longitudinal vertical median plane XZ of the vehicle are arranged symmetrically, so that the description of one of these parts is valid mutatis mutandis for the other.

[0040] The base 1 comprises a first hollow side flap 2 and a second hollow side flap (not visible on [Fig.1]) each extending along the longitudinal direction X of the vehicle.

[0041] These side skirts are structural elements of the vehicle, also commonly called "side members". The side skirts extend in particular under the vehicle doors and are part of the vehicle body.

[0042] The base 1 further comprises a housing 3 for an electric battery (not shown), which housing 3 is positioned between the first and second side flaps 2. In other words, the first and second side flaps 2 are positioned on either side of the housing 3.

[0043] The conditioning unit 3 is here arranged under an upper floor (not shown) of the subframe 1, here formed by the vehicle body floor.

[0044] The electric battery stored in the packaging case 3 can be packaged in the form of modules each incorporating a plurality of electrochemical cells, the packaging case 3 forming a protective enclosure or housing for the battery.

[0045] The base 1 further comprises a load distribution structure 4 with arched elements located in the lateral drip edge 2.

[0046] The force distribution structure 4 generally comprises at least one arch element 5, the structure 4 here comprising four arch elements 5 ([Fig.1]).

[0047] Each arched element 5 comprises two feet 6 and an arch 7 extending from one to the other of the feet 6.

[0048] The load distribution structure 4 is arranged so that the feet 6 are turned towards the conditioning box 3 and the arch 7 is turned away from the conditioning box 3. In other words, the concavity defined by the arched elements 5 is mainly directed towards the conditioning box 3, in order to distribute loads mainly directed towards the conditioning box 3.

[0049] We will now describe in more detail the drip edge 2, with reference to figures 1 to 3, [Fig.3] illustrating another embodiment of the invention.

[0050] The flap 2 is here tubular and has an internal face 14 which delimits its internal space 16 or "hollow" and an external face 15 opposite to the internal face 14.

[0051] The drip edge 2 here has a cross-section (i.e. along the XY plane) generally rectangular ([Fig.3]) and has an upper wall 8 and a lower wall 9 opposite each other, as well as an external side wall 10 ([Fig.1]) and an internal side wall 11 opposite each other and extending each from the upper wall 8 to the lower wall 9.

[0052] The upper wall 8 and the lower wall 9 are so named because they are respectively located one above the other in the vehicle.

[0053] The inner side wall 11 and the outer side wall 10 are so named because they are respectively located, along the transverse axis Y, further towards the interior of the vehicle, in particular towards the housing 3, and further towards the exterior of the vehicle.

[0054] The inner side wall 11 and the outer side wall 10 each generally extend along a vertical plane (defined by the X and Z axes) of the vehicle.

[0055] The upper wall 8 and the lower wall 9 each generally extend along a horizontal plane (defined by the X and Y axes) of the vehicle.

[0056] The flap 2 here has a closed cross-section, that is to say without interruption.

[0057] The flap 2 is here formed in two parts, namely an outer part 12 and a internal part 13, each with a cross-section (i.e. along the XY plane) generally in omega shape, whose respective distal ends 17 (figures 2 and 3) meet approximately in the middle of the upper wall 8 and in the middle of the lower wall 9. These distal ends 17 are here fixed to each other by welding.

[0058] The external part 12 and the internal part 13 are so named for the same reasons as the internal side wall 11 and the external side wall 10.

[0059] The external part 12 is also commonly referred to as the "body side reinforcement". The internal part 13 is also commonly referred to as the "flap closure element" by those skilled in the art.

[0060] We will now describe in more detail the packaging box 3 with reference to figures 1 to 3.

[0061] The conditioning unit 3 has in horizontal section a generally rectangular shape and thus comprises a first side 43 and a second side (not shown) opposite the first side 43, as well as a front side 44 and a rear side 45 opposite the front side 44.

[0062] The conditioning housing 3 further comprises a plurality of internal transverse beams, or crossbeams, 22 oriented transversely to the side flap 2, here more precisely along the transverse axis Y of the vehicle.

[0063] The cross members 22 each extend from the lateral side 43 to the opposite lateral side of the housing 3 and delimit between them compartments 23 ([Fig.1]) for the battery modules (not illustrated).

[0064] The packaging case 3 further includes a first lateral rim 46 and a second lateral rim (not shown), projecting respectively from the first lateral side 43 and the second lateral side (not shown).

[0065] The first lateral rim 46 is thus arranged opposite the lateral flap 2 and the second lateral rim (not shown) is arranged opposite the other lateral flap.

[0066] Only the first lateral rim 46 is described below, it being understood that this description applies mutatis mutandis to the second lateral rim (not shown) which is symmetrical to it.

[0067] The first lateral edge 46 forms with the first lateral side 43 a right-angled element 49 which has a cross-section (along the plane defined by the Y and Z axes) in L, which element 49 thus comprises a first portion substantially vertical formed by the first lateral side 43 of the conditioning unit 3, and a second substantially horizontal portion 47 extending from the first portion 43, here substantially perpendicularly.

[0068] In the illustrated example, the second portion 47 extends from a lower end of the first portion 43.

[0069] The second portion 47 extends towards the lateral flap 2, and has a terminal portion 50 supporting the latter from below, essentially at the place of the feet 6 and less, or even not, at the place of the arches 7 whose distance to the casing 3 is variable along the X axis.

[0070] The first lateral flange 46 is fixed to the first drip edge 2 by means of its end portion 50, which is here fixed to the lower wall 9 of the drip edge 2. Alternatively, or in addition, the end portion 50 is fixed to the load distribution structure 4 of the lateral drip edge 2 by means of fasteners (not shown) passing through the lower wall 9. This arrangement and this fastening sandwich the inner part 13 of the drip edge 2 between the load distribution structure 4 and the first lateral flange 46. The fastening is typically achieved by a series of screws (not shown) distributed along the drip edge 2, each screw cooperating with a corresponding nut crimped or welded to the drip edge 2.

[0071] The subframe 1 further comprises a plurality of structural struts 48 ([Fig. 1]) positioned between the conditioning unit 3 and the drip edge 2 (as well as between the conditioning unit 3 and the other side drip edge). The structural struts 48 are distributed along the longitudinal direction X of the vehicle.

[0072] It should be noted that, to improve clarity, the spacers are not shown in the cross-sectional view of [Fig.2].

[0073] The structural spacers 48 are here each formed by a flared rigid body whose section widens from the housing 3 towards the flap 2. The structural spacers 48 are here each made from a piece of sheet metal, shaped by stamping and / or bending.

[0074] The structural spacers 48 are here fixed to the inner part 13 of the flap 2, here by welding. Alternatively, the structural spacers 48 are fixed to the packaging housing 3 and / or to the side flap 2.

[0075] The structural spacers 48 help to eliminate play between the conditioning housing 3 and the flap 2 to achieve structural continuity which will concentrate energy absorption and deformation mainly in the flap 2 during a lateral impact, while preserving the integrity of the conditioning housing 3.

[0076] The structural spacers 48 are here further arranged here, each in line with a respective cross member 22 of the conditioning unit 3. Such The arrangement of the spacers 48 contributes advantageously to the distribution of forces towards the crossbeams 22.

[0077] We will now describe in more detail a first embodiment of the force distribution structure 4 in support of figures 1 and 2.

[0078] The structure 4 extends longitudinally between a rear end 20 and a front end 21 opposite the rear end 20.

[0079] Structure 4 extends here over a major part of the length of the flap 2. Note that here ([Fig.1]) structure 4 extends continuously over the entire length of the housing 3.

[0080] The structure 4 has, extending each from the rear end 20 to the front end 21: an upper longitudinal face 24, a lower longitudinal face 25, an internal longitudinal face 26 and an external longitudinal face 27 respectively turned towards the top of the vehicle, the bottom of the vehicle, towards the housing 3 and away from the housing 3.

[0081] As can be seen in [Fig.1], the load distribution structure is arranged in the drip edge 2 so that the feet 6 of the arched elements 5 are in contact with the internal side wall 11 of the drip edge 2. At the point of contact between the feet 6 and the wall 11, the internal longitudinal face 26 of the structure 4 has straight portions 29 which thus promote the transmission of loads.

[0082] It will be noted that here the vaults 7 of the arched elements 5 are located at a distance from the external side wall 10 of the valance 2 ([Fig.l]).

[0083] It will also be noted that the feet 6 are located, for three of them here, in the extension of a respective internal cross member 22 of the housing 3. In addition here, some other feet 6 are located in the extension of the front side 44 and the rear side 45 of the housing 3, which here form so-called external cross members similar to the internal cross members 22.

[0084] Such an arrangement of the feet 6 of the arched elements 5 in relation to the internal crossbeams 22 and / or the front 44 and rear 45 sides of the housing 3 contributes advantageously to the distribution of forces towards the internal crossbeams 22 and / or the front 44 and rear 45 sides.

[0085] Generally, when a post is impacted in line with a cross member 22, the compression of the corresponding region of the flange 2 and the reaction of the cross member 22 of the housing 3 are sufficient to stop the post before it crushes the battery cells. When the post is impacted between two cross members, the arched element 5 located between (the virtual extensions of) these two cross members contributes to transferring the forces onto these two cross members, increasing the overall reaction force of the housing 3 structure, possibly further reinforced by the optional presence of the spacers 48. In addition, the space between the inner side wall 11 of the flange 2 and the intrados of the arched element 5 allows the latter to flex and thus absorb the impact energy before transmitting it to the internal lateral wall 11 of the flap 2. In other words, the allowed deflection for the structure 4 and therefore the absorbed impact energy are increased.

[0086] The force distribution structure 4 is here in one piece, here of constant and continuous section.

[0087] The force distribution structure 4 here comprises a rigid profiled body 18 having a plurality of shaped regions 19 to give each an arched element 5.

[0088] The profiled body 18 is here made from a sheet or metal foil, for example in steel or aluminium, shaped by multiple bendings and / or hydroforming.

[0089] The profiled body 18 here has a generally rectangular section (figures 2 and 3), the longitudinal faces 24, 25, 26 and 27 being here generally flat.

[0090] The structure 4 has a longitudinal groove 28 ([Fig.2]) formed in the external longitudinal face 27, extending here over the entire length of the structure 4. This longitudinal groove 28 is formed here by a fold of the metal sheet or metal plate towards the inside of the profile 18.

[0091] The structure 4 is further alveolated, here presenting two alveoli 30, each alveoli 30 having here in section a generally rectangular shape.

[0092] The structure 4 here has the form of a serpentine ([Fig. 1]) having alternating first curved segments 31 and second curved segments 32, the second curved segments 32 having a smaller radius of curvature than that of the first curved segments 31. The second curved segments 32 each form the foot 6 of an arched element 5. The first curved segments 31 each form the vault 7 of an arched element 5.

[0093] Generally, the radius of curvature of the first curved segments 31 is between 100mm and 2000mm, and the radius of curvature of the second curved segments 32 is between 10mm and 1000mm.

[0094] We will now describe variants of the force distribution structure 4 in support of figures 3 to 8. It will be noted that in figures 4 to 8 the force distribution structure is represented very schematically; in addition, for convenience, only the internal part 13 of the flap is shown.

[0095] The force distribution structure 104 shown in [Fig.3] is similar to structure 4, except in particular that it comprises a plurality of longitudinal sections 33, 34, 35 and 36 placed side by side, each here being in a single piece.

[0096] Longitudinal section means that the boundaries which separate these sections 33, 34, 35 and 36 are generally oriented along the longitudinal axis X.

[0097] Longitudinal sections 33 and 34, as well as 35 and 36, are here superimposed in pairs, that is to say placed side by side along the vertical axis Z. Longitudinal sections 34 and 36, as well as 33 and 35, are juxtaposed laterally, that is to say placed side by side along the transverse axis Y.

[0098] Structure 104 further presents here 6 alveoli 30.

[0099] Structure 104 further presents here 4 longitudinal grooves 28, two of which two others formed in its internal longitudinal face 26 and two others formed in its external longitudinal face 27, and each forming part of a respective longitudinal section 33, 34, 35 and 36.

[0100] The force distribution structure 204 shown in [Fig.4] is similar to structure 4, except in particular that it comprises a plurality of cross sections 37 placed end to end, here all identical.

[0101] Cross section means that the boundaries which separate these sections 37 are generally oriented along a vertical plane defined by the Y and Z axes.

[0102] The structure 204 further presents here only first curved segments 31 which form both the vault 7 and the feet 6 of the arched elements 5, each cross section 37 forming here entirely a curved segment 31.

[0103] The force distribution structure 304 shown in [Fig.5] is similar to the structure 204, except in particular that it comprises both a plurality of cross sections 38 placed end to end and a plurality of longitudinal sections 39 placed side by side.

[0104] The load distribution structure 404 shown in [Fig. 6] is similar to the structure 304, except in particular that it lacks cross-sections and that its internal longitudinal face 26 lacks straight portions such as 29 but is continuously curved. In general, the structure 404 is continuously curved, here along its entire length.

[0105] The longitudinal sections 33, 34, 35, 36, 39 and / or transverse sections 37, 38 of the above embodiments are fixed together, for example by welding, screwing or any other process.

[0106] The force distribution structure 504 shown in [Fig.7] is similar to the structure 204, except in particular that the radius of curvature of its first curved segments 31 is larger.

[0107] The force distribution structure 604 shown in [Fig.8] is similar to the structure 504, except in particular that the structure 604 is interrupted, presenting here two pieces 40 and 41 not directly connected to each other, and that it also includes straight segments 42.

[0108] In other variants not shown:

[0109] - the substructure lacks structural braces, so there is a play between the drip edge and the battery conditioning unit;

[0110] - the vault of the arched elements, in particular its apex, is not at a distance but is in contact with the external side wall of the flap;

[0111] - the cells of the load distribution structure have a cross-sectional shape different from rectangular, for example circular, oval or triangular; and / or

[0112] - the arched elements of the force distribution structure are not all identical but exhibiting varied lengths, widths, curvatures, shapes, and interruptions.

[0113] More generally, the invention is not limited to the examples described and represented.

Claims

Demands

1. Underbody (1) for an electric or hybrid motor vehicle comprising: - a hollow side flap (2), - a battery conditioning unit (3), and - a load distribution structure (4; 104; 204; 304; 404; 504; 604) comprising at least one arched element (5) whose feet (6) are turned towards said battery conditioning unit (3) and the arch (7) opposite said battery conditioning unit (3); characterized in that said load distribution structure (4; 104; 204; 304; 404; 504; 604) is located in said side flap (2).

2. Base according to claim 1, wherein said load distribution structure (4; 104; 204; 304; 404; 504; 604) comprises a rigid profiled body (18) having at least one shaped region (19) to give said at least one arched element (5).

3. Base according to claim 1 or 2, wherein said load distribution structure (4; 104; 404) has the form of a serpentine having alternating first curved segments (31) and second curved segments (32), said second curved segments (32) having a smaller radius of curvature than said first curved segments (31), said second curved segments (32) each forming said foot (6) of said arched element (5), said first curved segments (31) each forming said arch (7) of said arched element (5).

4. Base according to any one of claims 1 to 3, wherein said load distribution structure (4; 104) is honeycombed, each honeycomb (30) having in section a generally rectangular shape.

5. Base according to any one of claims 1 to 4, wherein said load distribution structure (4; 104) has two opposite longitudinal faces (26, 27) turned respectively towards said conditioning box (3) and away from said conditioning box (3), said load distribution structure having at least one longitudinal groove (28) formed in at least one of said longitudinal faces (26, 27).

6. Base according to any one of claims 1 to 5, wherein said load distribution structure (204; 304; 404; 604) comprises a plurality of cross sections (37; 38) placed end to end and / or longitudinal sections (33, 34, 35, 36; 39) placed side by side.

7. Base according to any one of claims 1 to 5, wherein said load distribution structure is in one piece (4; 104; 404).

8. Base according to any one of claims 1 to 7, wherein said packaging box (3) comprises cross members (22, 44, 45) oriented transversely to said side flap (2), at least one of said feet (6) of said arched element (5) being located in the extension of said cross member (22, 44, 45).

9. Base according to claim 8, wherein a plurality of spacers (48) are each arranged in the extension of a respective cross member (22, 44, 45), between said drip edge (2) and said packaging box (3).

10. Electric or hybrid motor vehicle comprising a chassis (1) according to any one of claims 1 to 9.

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