CAR BODY WITH A HOUSING FOR AN ELECTRIC TRACTION BATTERY

Description

[0001] The present invention claims priority from French application No. 2204955 filed on 24.05.2022.

[0002] The present invention relates to a motor vehicle body comprising a battery box for powering an electric traction machine of the vehicle, as well as an electric motor vehicle equipped with such a body.

[0003] A type of motor vehicle featuring a battery box for powering an electric traction machine, as described in document DE-A1-102011017459, has a passenger compartment floor with a lower cover attached to its perimeter underneath, forming a closed box between the floor and this cover to house the battery. A seal between the perimeter of the cover and the floor provides a watertight seal for the box protecting the battery. However, this type of box, formed in the middle of the floor in a relatively flat area, offers little rigidity. Furthermore, the full width of the vehicle, available between the two side rails framing the vehicle's body floor, is not utilized.

[0004] Another known type of electric vehicle, notably described in document US-A1-20190074494, features a housing with a cooled base plate that supports the battery cells. This plate is flanked on each side by an extruded aluminum alloy profile, each attached to a side rail of the floor. This profile provides high mechanical strength to protect the battery from lateral impacts to the vehicle. A cover is fitted over the top of the two profiles to seal the housing, which is then mounted under the vehicle.

[0005] In this case, on the sides of the box, a peripheral frame is placed between the stringers and the battery elements, which reduces the width of the available internal volume, and on the top of the box, a cover plate is placed below the floor plate, with a minimum gap that can be about 10mm to avoid any risk of interference, which also reduces the internal volume in height.

[0006] US document 2019 / 009662 A1 describes an electric motor vehicle body according to the preamble of claim 1.

[0007] In general, the bodies of electric motor vehicles must, like those of other vehicles, be watertight, and also have a particular seal against fumes that may be released by the battery during damage causing thermal runaway in order to avoid potentially serious incidents with passengers.

[0008] Current standards require the battery casing to be dustproof and watertight with an IP67 protection rating according to the International Electrotechnical Commission (IEC) standard, in order to prevent any water from entering its casing which could cause a short circuit of the electrical elements, and any leakage to the outside of internal products of these batteries.

[0009] Creating an independent box fixed under the vehicle body allows the sealing functions of this box to be separated from the sealing of the body, which have different characteristics, but poses problems of limiting the available interior volume, and of the greater number of components which increases the mass of the vehicle as well as the costs.

[0010] The present invention aims in particular to avoid these problems of the prior art. To this end, it proposes an electric motor vehicle body comprising a floor plate, side members, a battery box disposed under the floor plate, and under this box a battery box cover, the floor plate being fixed on each side to one of the side members, these side members having a substantially horizontal lower face, this vehicle body being remarkable in that the edges of the floor plate overlap under the lower faces of the side members, the floor plate and the edges of this plate have a vehicle body seal that is watertight and fume-proof, and in that the sides of the cover have a flat face that overlaps under the edges of the floor plate with a battery box seal that is dustproof and watertight.

[0011] One advantage of this vehicle body is that by positioning the floor panel edges under the lower face of the side members, and the sides of the cover below these edges, the floor panel edges terminate outside the vehicle, rather than inside the body. This allows for the standard, simple, and economical sealing required for vehicle bodies between the floor panel edges and the side members.

[0012] The battery compartment is formed directly within the vehicle's body structure, with the side members providing the necessary lateral reinforcement to protect the battery cells. This eliminates the need for a peripheral frame, which would take up width, and a top cover for the battery compartment, which would take up height. This maximizes the volume available for the battery cells, thus extending the electric vehicle's range. It also reduces the number of structural components, thereby decreasing the vehicle's weight and lowering costs.

[0013] The electric vehicle body according to the invention may further comprise one or more of the following features, which may be combined. Advantageously, the floor panel comprises a downward-sloping portion disposed in front of each edge of the floor panel, which is attached to a substantially vertical portion on the inner side of the side member.

[0014] Advantageously, the edges of the floor sheet metal are welded under the lower faces of the longitudinal member.

[0015] Advantageously, the lower faces of the side members have a downward fold on the exterior side of the vehicle, with the vehicle body sealant applied between the edge of the floor panel and the recess formed by this downward fold. Advantageously, the flat face of the lid sides is framed around the lid's perimeter by downward stiffening folds.

[0016] Advantageously, the flat face of the lid sides is fixed to the stringers by a series of screws passing successively through this flat face, the edge of the floor sheet and the lower face of the stringer.

[0017] Advantageously, the floor plate has stiffening cross members welded directly underneath it.

[0018] In this case, advantageously the stiffening crossbeams include spacers fixed underneath, receiving the support of the cover.

[0019] Advantageously, the lid has reinforcing crossbars on its upper face aligned with the spacers.

[0020] The invention also relates to an electric motor vehicle equipped with a traction battery, remarkable in that it comprises a vehicle body including any of the preceding characteristics, having battery elements fixed on the lid.

[0021] The invention will be better understood and other features and advantages will become more apparent upon reading the following description, given by way of example, with reference to the accompanying drawings in which: [ Fig. 1 ] is a bottom view of a vehicle body according to the invention with its lower battery box cover; [ Fig. 2 ] is a cross-sectional view of one side of the battery box at the level of a reinforcing crossmember; and [ Fig. 3 ] is a perspective view of this side of the battery box.

[0022] Throughout the document the upper or top side relates to a motor vehicle placed on a flat horizontal ground, the inner or outer sides are, according to the transverse direction of the vehicle, respectively turned towards the central axis or outwards.

[0023] THE figures 1, 2 And 3present the base of a motor vehicle body comprising on each side an inner longitudinal member 2, extended forward by a front longitudinal member 4 and rearward by a rear longitudinal member 6. The longitudinal members 2 are connected forward by a front cross member 8 and rearward by a rear cross member 10, forming between these four elements a battery box covered by a substantially flat floor plate 12.

[0024] Each inner longitudinal member plate 2 has a substantially horizontal upper part, a substantially vertical part facing inwards towards the vehicle 32, and then a substantially horizontal lower face 34. The edges of the longitudinal member plate 2 facing outwards have an upward fold 52 in the upper part and a downward fold 54 in the lower part, these folds receiving by welding an outer longitudinal member plate not shown to close this longitudinal member.

[0025] The welding areas between the sheets are indicated by the dotted markings 58.

[0026] The floor plate 12 receives upper cross members 56 providing rigidity and allowing the attachment of equipment such as seats.

[0027] The floor plate 12 receives four lower cross members 14 welded directly beneath it, distributed along the length of the battery box, in order to reinforce it by defining spaces to receive battery components. Each lower cross member 14 has vertical struts 16 extending below the underside of the cross member, their bases forming a lower plane.

[0028] The contour of the floor plate 12 has a descending part 30 which is attached to the substantially vertical part 32 of the stringer plate 2, then ends with a horizontal edge 36 supported under the horizontal lower face of the stringer plate 34, spot welds connecting these two parts to ensure a strongly rigid connection between the floor and the stringers.

[0029] The entire floor panel provides a complete seal against the body. A bead of sealant 38 is then applied to both the edge of the floor panel 12 and the underside of the side member panel 34 in the recess formed by the downward fold 54. With the floor panel and its entire perimeter forming a seal against water and fumes, there can be no smoke rising from the battery located under the vehicle body in the event of an incident, and escaping from its compartment.

[0030] A cover comprising a main sheet 20 has below each lower cross member 14 a transverse rib 22 projecting upwards, framed above by a cover reinforcement cross member 26, and below by a flat sheet 24. The lower flat sheet 24 has holes for the passage of a tool 28 allowing screws to be screwed through the cover sheet 20 and the cover reinforcement cross member 26, which are engaged under the spacers 16 to fix this cover below.

[0031] The cover reinforcement cross members 26 have vertical threaded rods 50 allowing the battery elements 56 to be fixed to this cover.

[0032] The cover 20 has on its sides a continuous flat horizontal face 40 following the entire contour, framed by downward folds 42 to provide rigidity. The flat side face 40 receives a peripheral sealing gasket 44, continuous around the contour, which is tightened under the horizontal floor edge 36 by a series of screws 46 passing through the cover, the floor plate 12, and the underside of the longitudinal plate 34.

[0033] The peripheral sealing gasket 44 has a reinforced seal designed for a battery box, ensuring a level of dust and water tightness of type IP67 in order to meet battery protection standards.

[0034] It should be noted that, in the absence of a separate upper cover for the battery box, the floor plate 12 performs this function, but its seal with the longeron 2 is located outside the box thanks to its horizontal edge of sheet metal 36, which extends beyond the cover 20 and out of the box. This provides a simple, standard box seal between the floor edge 36 and the underside of the longeron 34 welded together, which is not subject to the high sealing requirements of the box.

[0035] Installing or removing the battery involves mounting or dismounting the lower cover 20, the battery elements being directly attached to it, which allows quick and easy access to the entire battery.

[0036] We obtain a maximum available volume for the battery which goes up to the floor plate of the passenger compartment 12, and on the sides to the longitudinal members 2 thanks to the descending part of the floor edge 30 which is attached to the vertical part of the longitudinal member 32.

Claims

1. Vehicle body structure for an electric motor vehicle comprising a floor panel (12), side members (2), a battery casing arranged below the floor panel (12), and, below this casing, a casing cover (20), the floor panel (12) being fixed on each side to one of the side members (2), said side members (2) having a substantially horizontal lower face (34), characterized in that edges (36) of the floor panel (12) overlap beneath the lower faces of the side members (34), the floor panel (12) and its edges (36) providing a vehicle body sealing (38) that is watertight and smoke-tight, and in that sides of the cover (20) have a flat face (40) overlapping beneath the edges of the floor panel (36), with a battery casing sealing (44) that is dust-tight and watertight provided therebetween.

2. Vehicle body structure according to claim 1, characterized in that the floor panel (12) comprises, upstream of each floor panel edge (36), a downwardly extending portion (30) abutting against a substantially vertical portion (32) of an inner side of the side member (2).

3. Vehicle body structure according to claim 1 or 2, characterized in that the edges of the floor panel (36) are welded beneath the lower faces of the side members (34).

4. Vehicle body structure according to claim 3, characterized in that the lower faces of the side members (34) comprise, toward an outer side of the vehicle, a downward fold (54), the vehicle body sealing (38) being applied between an end of the floor panel edge (36) and a recess formed by said downward fold (54).

5. Vehicle body structure according to any one of the preceding claims, characterized in that the flat face of the cover sides (40) is bordered along a perimeter of said cover (20) by downwardly extending stiffening folds (42).

6. Vehicle body structure according to any one of the preceding claims, characterized in that the flat face of the cover sides (40) is fixed to the side members (2) by a series of screws (46) passing successively through said flat face, the floor panel edge (36), and the lower face of the side member (34).

7. Vehicle body structure according to any one of the preceding claims, characterized in that the floor panel (12) comprises stiffening cross members (14) directly welded beneath said floor panel.

8. Vehicle body structure according to claim 7, characterized in that the stiffening cross members (14) comprise spacers (16) fixed underneath, receiving a support of the cover (20).

9. Vehicle body structure according to claim 8, characterized in that the cover (20) comprises, on its upper face, reinforcing cross members (26) aligned with the spacers (16).

10. Electric motor vehicle equipped with a traction battery, characterized in that it comprises a vehicle body structure according to any one of the preceding claims, having battery elements (56) fixed on the cover (20).