Energy Storage Underbody for a Motor Car Body-in-White

Abstract

An energy storage underbody for a motor car body-in-white has a vehicle floor laterally delimited by side sills and reinforced by side members and/or cross members. An energy storage device is disposed on the underside of the vehicle floor. In order to obtain an energy storage device of particularly simple construction and a particularly economical, stiffened underbody, the energy storage underbody has at least one housing of the energy storage device, the housing being non-load bearing in terms of the body-in-white, and has at least one additional side member or cross member disposed on the topside of the vehicle floor to reinforce the underbody.

Claims

1.-10. (canceled)

11. An energy storage underbody for a motor car body-in-white, comprising: a vehicle floor delimited laterally by respective side rocker panels and stiffened by crossmembers; an energy storage device arranged on an underside of the vehicle floor, wherein the energy absorption device is provided within a respective side rocker panel, and the energy absorption device extends at least over a length region of an associated side rocker panel and at a level of the crossmembers.

12. The energy storage underbody according to claim 11, further comprising: at least one housing of the energy storage device that is non-load-bearing with respect to the body-in-white; and an at least one additional longitudinal member or crossmember arranged on an upper side of the vehicle floor for stiffening the underbody.

13. The energy storage underbody according to claim 12, wherein the at least one housing of the energy storage device is arranged at a distance from the side rocker panels or from a front or rear crossmember of the underbody.

14. The energy storage underbody according to claim 12, wherein the at least one housing has arranged on an underside thereof a carrier element via which the at least one housing is held on the underside of the vehicle floor, the carrier element being arranged at a distance from the side rocker panels or from a front or rear crossmember of the underbody.

15. The energy storage underbody according to claim 11, wherein a clearance is provided between the energy storage device and the respective side rocker panel.

16. The energy storage underbody according to claim 11, further comprising: a supporting element provided between the energy storage device and the respective side rocker panel, at the level of which supporting element a further energy absorption device arranged below the first energy absorption device extends at least over a length region of the associated side rocker panel.

17. The energy storage underbody according to claim 16, wherein the respective energy absorption device is formed by a plurality of profile parts which follow one another in the vehicle transverse direction.

18. The energy storage underbody according to claim 17, wherein the plurality of profile parts are formed by a plurality of parts constructed separately from one another.

19. The energy storage underbody according to claim 17, wherein the plurality of profile parts are formed by a one-piece structural element having the respective profile parts.

20. The energy storage underbody according to claim 12, wherein to stiffen the underbody, the at least one crossmember arranged on the upper side of the vehicle floor is provided, in addition to in any case present seat crossmembers, and extends continuously between the side rocker panels.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a schematic bottom view of a motor car body having an energy storage underbody in which a vehicle floor is delimited laterally by respective side rocker panels and stiffened by longitudinal members and/or crossmembers, and in which an energy storage device is arranged on the underside of the vehicle floor that comprises a plurality of housings which extend in the vehicle longitudinal direction and are designed to be non-load-bearing with respect to the body-in-white.

[0020] FIG. 2 shows a perspective sectional view through the energy storage underbody according to FIG. 1 along a section plane which extends in the vehicle vertical direction or in the vehicle transverse direction, wherein an energy absorption device is provided within the respective side rocker panel, which device extends at least over a length region of the associated side rocker panel and at the level of the crossmembers.

[0021] FIG. 3 shows a sectional view, in the form of a detail, of the energy storage underbody according to FIGS. 1 and 2 along a section plane extending in the vehicle transverse direction or vehicle vertical direction, wherein the energy absorption device which is arranged within the respective side rocker panel and extends at least over a length region of the associated side rocker panel and at the level of the crossmembers can be seen.

[0022] FIG. 4 shows a perspective view, in the form of a detail, of the vehicle floor of the underbody of the motor car body-in-white, with there being able to be seen, apart from the seat crossmembers, additional crossmembers for stiffening the underbody.

[0023] FIG. 5 shows a schematic sectional view through an alternatively constructed energy absorption device within the respective side rocker panel of the energy storage underbody.

[0024] FIG. 6 shows a sectional view, in the form of a detail, of the energy storage underbody in an alternative embodiment to that according to FIGS. 1 to 3 along a section plane extending in the vehicle transverse direction or vehicle vertical direction.

DETAILED DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a perspective bottom view showing a motor car body-in-white of a passenger motor car. Here, an energy storage underbody is formed by a body-in-white underbody 1, which will be explained in more detail below, and an energy storage device 2, which is illustrated here in exploded view beneath the underbody 1. The energy storage device 2 allows electrical energy to be able to supplied to a drive of the motor car, which is, for example, driven with a fully electrical drive or by means of a hybrid drive.

[0026] The underbody 1 is substantially formed by a, here mostly planar, vehicle floor 3, which is formed in particular from one or more shaped sheet-metal components. This vehicle floor 3 is delimited laterally by respective side rocker panels 4, 5 which extend substantially horizontally in the vehicle transverse direction between respective front and rear wheelhouses 6, 7 of each vehicle side. In the front region, the underbody 1 is delimited toward the front by a front crossmember 8 which—with respect to the vehicle longitudinal direction—extends at the level of a firewall 9 which partitions the vehicle cell off from the front-end structure of the motor car. Here, the crossmember 8 extends horizontally and in the vehicle transverse direction between respective front ends of the side rocker panels 4, 5 or lower ends of corresponding front door pillars 10. In a rear region, the underbody has a rear crossmember 11 which extends horizontally and in the vehicle transverse direction approximately—with respect to the vehicle longitudinal direction—at the level of the respective rear ends of the side rocker panels 4, 5. The vehicle floor 3, together with the side rocker panels 4, 5 and the crossmembers 8, 11, forms a downwardly open trough in which the energy storage device 2 is arranged below the vehicle floor 3 in a manner which will be descried in more detail below.

[0027] Here, the arrangement of the energy storage device 2 below the vehicle floor 3 will be explained below on the basis of FIGS. 2 and 3, which show the energy storage underbody in a perspective view or a sectional view from the front in each case along a section plane running in the vehicle transverse direction or in the vehicle vertical direction. It can be seen here that the energy storage device 2 comprises a plurality of, in the present case six, individual housings 12 which, in each case consisting of a cross-sectionally substantially U-shaped upper part 13 and a likewise substantially cross-sectionally U-shaped lower part 14, are connected to one another along a respective flanged connection 15. Here, the flanged connection 15 is formed by respective flanges of the upper part 13 and of the lower part 14 and extends in circumferentially enclosing closed fashion around the respective overall housing 12. As a result, battery cells or battery module 16 that are arranged within the respective housing 12 are received tightly within the respectively assigned housing 12.

[0028] Here, the plurality of housings 12 extend parallel to one another approximately horizontally and in the vehicle longitudinal direction. To the side of each of the housings 12, or between the individual housings 12, a respective holding profile 17 extends horizontally and in the vehicle longitudinal direction and has here, as viewed substantially in cross section, a hat profile and is fixed by means of respective flanges 18 to the underside of the vehicle floor 3, for example by way of a welded connection or some other kind of joining connection. The holding profiles 17 are here particularly also visible in FIG. 1 on the underside of the vehicle floor 3. They serve primarily to hold the energy storage device 2, which is formed by the plurality of housings 12. Accordingly, the holding profiles 17 are also arranged outside of the energy storage device 2.

[0029] Particularly in FIG. 1 there can be seen a carrier element 19 in the form of a carrier plate which, for example, can take the form of a shaped sheet-metal part, a plastics component or a cast metal component. In the present case, the carrier plate (carrier element 19) is designed to be substantially planar and has on its upper side respective clamping rails 20 which, in the respective central region between the individual housings 12, are configured to be double-T-shaped and, to the outside of the outermost housing 12, are configured in the manner of a box profile as viewed in cross section. These clamping rails 20 are, for example, fastened to the upper side or inner side of the carrier element 19 by way of a welded connection, some other joining connection or the like, and are aligned with the respectively corresponding holding profile 17, which for its part is fastened to the underside of the vehicle floor 3. Accordingly, the respective clamping rails 20 also extend at least substantially horizontally and in the vehicle longitudinal direction when the carrier element 19 is mounted on the underbody 1.

[0030] During the mounting operation, the carrier element 19 with the clamping rails 20 is equipped with the individual housings 12 and then fastened to the underside of the vehicle floor 3. Here, the housings 12 have their respective flanged connections 15 clamped between respective holding profile 17 and the respective clamping rail 20 by virtue of the carrier plate being fastened to the underside of the vehicle floor 3. This is primarily effected by corresponding bolted connections or other mechanical connection means being set between the carrier element 19 or the respective clamping rail 20 and the associated holding profile 17, with the result that the respective flanged connection 15 of the corresponding housing 12 is clamped between the respective holding profile 17 and the associated clamping rail 20. The carrier plate here serves not only for mounting and holding the respective housings 12, but also for protecting them. Particularly in the case of traveling over a bollard, the respective housings 12 are thus optimally protected from damage.

[0031] It can particularly also be seen from FIGS. 2 and 3 that both the respective housings 12 and the carrier plate (carrier element 19) terminate at a lateral distance from the respectively corresponding side rocker panel 4, 5. In other words, a clearance 25, which extends upwardly toward the underside of the vehicle floor 3, is provided between the energy storage device 2 and the respective side rocker panel 4, 5. There is therefore substantially no connection between the energy storage device 2 and the respective side rocker panel 4, 5 below the vehicle floor 3.

[0032] Moreover, it can be seen in particular from FIGS. 2 and 3 that the respective housing 12 with the respective upper parts 13 and lower parts 14 is designed to be substantially without a load-bearing structure. This means in particular that no bearers or bearer-like depressions are provided that would contribute in particular to stiffening the body in the vehicle transverse direction. It is also the case that, by contrast with the prior art to date, there is no frame provided which runs in an encircling manner around the energy storage device and via which the latter could be attached, for example, to the side rocker panels 4, 5. Toward the front or toward the rear in the vehicle longitudinal direction there can also be provided respective distances between the respective housings 12 and the corresponding crossmembers 8 and 11. This also applies to the carrier plate, which may, where appropriate, likewise terminate at a distance from said crossmembers 8, 11.

[0033] Since the energy storage device 2, and in particular its housing 12, does indeed have a sealing function for the battery module 16 arranged within it, but in particular no stiffening and load-bearing properties for the motor car body-in-white, there occurs additional stiffening of the underbody, as can be seen from FIG. 4 in a perspective and detail plan view. It can be seen in particular here that, in addition to respective seat crossmembers 21, 22, there are provided in the present case two further crossmembers 23, 24 which have up until now not been required on energy storage underbodies created in the conventional way according to the above-described prior art. Since namely, according to the invention, the respective housings 12 do not have a load-bearing and stiffening function for the motor car body-in-white or the underbody 1, this is accomplished by the crossmembers 23, 24 which extend on the upper side of the vehicle floor 3 or are fixed to the upper side thereof. The crossmembers 23, 24 extend here over the full width of the underbody between the two side rocker panels 4, 5, on which they are supported and also fastened. This results in two optimal load paths between the respective side rocker panels 4, 5 without—as in the prior art to date—a diversionary path having to be chosen by way of corresponding load transfer points in the form of bolts or the like at which the load was transferred from the underbody or the motor car body-in-white, in particular from the side rocker panels 4, 5, to the energy storage device 2 and its housing 12.

[0034] It is evident here that load paths are thus created which have been created in a simple manner by means of the respective crossmembers 23, 24 and can be welded in a simple manner and accordingly are attached not only in pointwise fashion. Moreover, a further main advantage of this design is that the described functional separation between the tightness of the respective housings 12 and the mechanical stiffening of the underbody 1 or of the motor car body-in-white is achieved. This makes it possible in particular for the respective housing 12 and the energy storage device 2 overall to be produced considerably more cost-effectively and, moreover, for an improved gripping function of the motor car body-in-white and of its underbody 1 to be achieved.

[0035] A further advantage is afforded by the fact that, between the side rocker panels 4, 5 and the energy storage device 2, in particular its housing 12, there is provided a gap or clearance 25 which is possible only by virtue of the fact that the respective housing 12 or the energy storage device 2 overall does not have to contribute to the stiffening of the underbody 1 and accordingly does not have to be necessarily fastened to the respective side rocker panel 4, 5. This particularly has the advantage that, in the event of a side impact of one of the side rocker panels 4, 5, there is a considerable distance to the energy storage device 2 or the respective housing 12, with the result that damage to the energy storage device 2 arises far later in the course of the accident scenario in the event of a side impact.

[0036] Since the energy storage device is formed from a plurality of individual housings 12 which, on account of their non-load-bearing function, do not have to be connected to one another, it is possible to dispense with an extremely complicated central attachment of the energy storage device 2 that has been required up until now. Rather, the individual housings 12 are optimally held in the underfloor region in particular by the combination of the carrier plate (carrier element 19) with the holding profiles 17 and the clamping rails 20.

[0037] As can be seen from the sectional views according to FIGS. 2 and 3, the respective side rocker panel 4, 5 has a respectively associated energy absorption device 26 arranged within it that extends at least over a length region in the vehicle longitudinal direction and horizontally within the associated side rocker panel 4, 5. Here, the energy absorption device 26—as viewed in the vehicle vertical direction—runs at least substantially at the level of the respective additional crossmembers 23, 24 or accordingly at the level of the seat crossmembers 21, 22 too, all of which are arranged above the vehicle floor. Here, in the present case, the energy absorption device 26 extends—with respect to the vehicle vertical direction—approximately over half the height of the corresponding seat crossmember 21 to 24 at the respective height thereof and downwardly beyond the vehicle floor 3 to a certain degree.

[0038] The energy absorption device 26 comprises in the present case a plurality of profile parts 27, 28, 29 which in the present case are formed by three chambers. The three profile parts 27, 28, 29 are accordingly to be understood as meaning the three chambers of the energy absorption device 26, which in the present case is a profile element which has been produced by roll-profiling a corresponding metal sheet. This means that the energy absorption device 26 is in the present case configured in one piece as a correspondingly roll-profiled shaped sheet-metal component as it is accordingly preferably formed in one piece. This one-piece nature allows a particularly simple structural element or rolled profile to be created.

[0039] It can additionally be seen from FIGS. 2 and 3 that this rolled profile, or the energy absorption device 26, is supported on the inner side of an inner rocker panel part 30 which for its part is connected to an outer rocker panel part 33 in the region of an upper flanged connection 31 and in the region of a lower, outer flanged connection 32. Where appropriate, the inner rocker panel part 30 can also be of multipart configuration.

[0040] In the present case, a cross-sectionally approximately M-shaped reinforcing part 34 is arranged within the cavity of the side rocker panel 4, 5 that is formed by the inner rocker panel part 30 and by the outer rocker panel part 33, wherein the rolled profile of the energy absorption device 26 is received within a chamber of this M-shaped reinforcing part 34. This means in the present case that the energy absorption device 26 does not extend outwardly in the vehicle transverse direction up to the outer rocker panel part 33, but rather is delimited on the outside by the reinforcing part 34. In other words, a clearance is provided between the reinforcing part 34 and the outer rocker panel part 33.

[0041] The rolled profile of the energy absorption device 26 can, for example, have a different material thickness over the extent thereof in order thereby to set the deformation behavior of the energy absorption device 26. The characteristics of the rolled profile, or of the energy absorption device 26, can also be set through suitable shaping or material selection.

[0042] If, for example in the event of a side impact or side collision, a corresponding obstacle, such as for example a pole, should now strike the underbody 1, the energy absorption device 26 ensures that impact energy is correspondingly absorbed, as has up until now occurred, for example, by means of a frame of a housing of the energy storage device. However, since in the present case the energy storage device 2 is designed to be non-load-bearing, or is arranged at a distance from the corresponding side rocker panels 4, 5 and accordingly forms the clearance 25, the energy absorption device 26 performs the function that has up until now been carried out by the frame of the housing of the energy storage device 2. The advantage resulting therefrom lies particularly in the fact that, in the event of a side impact, first of all the energy absorption device 26 is damaged and not for instance the energy storage device 2. In this regard, damage to the side rocker panel 4, 5 or to the energy absorption device 26 can be far better and more cost-effectively rectified than damage to the frame of the housing of the energy storage device, as was usually the case up until now. Moreover, as already described above, the energy storage device 2 can thus be designed to be non-load-bearing.

[0043] FIG. 5 is a schematic sectional view illustrating an alternatively formed energy absorption device 26 within the respective side rocker panel 4, 5. This energy absorption device 26 is in the present case formed by three separate profile parts 35, 36, 37 in the form of respective, approximately cross-sectionally rectangular rolled steel profiles which are connected to one another via respective laser seams 38. Moreover, the assembly of the profile parts 35, 36, 37 is also fastened, via corresponding laser seams 38, to the inner rocker panel part 30 and outer rocker panel part 33. A particular feature that can be seen in the present case is that the respective rolled steel profiles have respective smaller wall thicknesses from inside to outside so as thereby to set the deformation behavior. It is of course also possible, for example, for other materials to be used.

[0044] Finally, FIG. 6 shows in a sectional view, in the form of a detail, the energy storage underbody in an alternative embodiment to that according to FIGS. 1 to 3 along a section plane running in the vehicle transverse direction or vehicle vertical direction. There can additionally be seen a pole 39 which is intended to illustrate a side impact or pole collision.

[0045] It can be seen from FIG. 6, by contrast with the embodiment according to FIGS. 1 to 3, that a supporting element 40, which extends downwardly starting from the vehicle floor 3, is provided in the clearance 25 between the energy storage device, more precisely between the respectively outermost holding profile 17 or the associated clamping rail 20, and the inner rocker panel part 30. Here, this supporting element 40 runs, in the vehicle longitudinal direction, approximately horizontally over a corresponding length region of the associated side rocker panel 4, 5. In the present case, the supporting element 40 is formed, for example, by an extruded profile having corresponding ribs. Of course, sheet-metal constructions or the like would also be conceivable here.

[0046] The supporting element 40 affords a further support possibility for a further energy absorption device 41, which runs at the level of the supporting element 40 in the vehicle longitudinal direction and approximately horizontally over a corresponding length region of the associated side rocker panel 4, 5 within the cavity thereof. In other words, the second energy absorption device 41, just like the first energy absorption device 26 arranged above it, runs within the cavity formed by the side rocker panel 4, 5.

[0047] By virtue of the two energy absorption devices 26, 41, there are thus formed two load paths, which are arranged one above the other in the vehicle vertical direction, in order to provide two load paths, or deformation planes, in the event of a collision with the pole 39 or some other obstacle. Here, respective force components can arise between the upper and lower load path or between the upper and lower energy absorption device 26, 41 as a result of suitable positioning, configuration and material selection.

[0048] Finally, it can be seen from FIG. 6 that in the present case each of the energy absorption devices 26, 41 is formed from a plurality of cross-sectionally hat profile-like profile parts 42, 43, 44 which can slide into one another in the event of a side impact.

LIST OF REFERENCE SIGNS

[0049] 1 Underbody [0050] 2 Energy storage device [0051] 3 Vehicle floor [0052] 4 Side rocker panel [0053] 5 Side rocker panel [0054] 6 Wheelhouse [0055] 7 Wheelhouse [0056] 8 Crossmember [0057] 9 Firewall [0058] 10 Door pillar [0059] 11 Crossmember [0060] 12 Housing [0061] 13 Upper part [0062] 14 Lower part [0063] 15 Flanged connection [0064] 16 Battery module [0065] 17 Holding profile [0066] 18 Flange [0067] 19 Carrier element [0068] 20 Clamping rail [0069] 21 Seat crossmember [0070] 22 Seat crossmember [0071] 23 Crossmember [0072] 24 Crossmember [0073] 25 Clearance [0074] 26 Energy absorption device [0075] 27 Profile part [0076] 28 Profile part [0077] 29 Profile part [0078] 30 Inner rocker panel part [0079] 31 Flanged connection [0080] 32 Flanged connection [0081] 33 Outer rocker panel part [0082] 34 Reinforcing part [0083] 35 Profile part [0084] 36 Profile part [0085] 37 Profile part [0086] 38 Laser seam [0087] 39 Pole [0088] 40 Supporting element [0089] 41 Energy absorption device [0090] 42 Profile part [0091] 43 Profile part [0092] 44 Profile part