MOTOR VEHICLE COMPRISING A BATTERY TRAY INCLUDING SIDE CROSS BEAMS WELDED TO INTER-MODULE CROSS BEAMS, AND METHOD FOR MANUFACTURED SUCH A VEHICLE

Abstract

The invention relates to a motor vehicle comprising a battery tray for receiving battery modules of a traction battery, the battery tray comprising: - a floor (P) defining the bottom of the battery tray at its lower part with respect to the vertical axis (Z); - inter-module cross members (TM) arranged above the floor (P), extending laterally along the lateral axis (Y) between battery module positions; - lateral cross members (TL) extending in a front-to-rear direction along the front-to-rear axis (X), arranged at the lateral ends of the inter-module cross members (TM) with respect to the lateral axis (Y), the inter-module cross members (TM) being fixed to the lateral cross members (TL). The invention also relates to a method for manufacturing such a vehicle. Figure 4

Description

Title of the invention: MOTOR VEHICLE COMPRISING A BATTERY TRAY INCLUDING SIDE CROSS BARS WELDED TO INTER-MODULE CROSS BEAMS, AND METHOD FOR MANUFACTURING SUCH A VEHICLE

[0001] The invention relates to the field of passive safety in motor vehicles, more particularly to the protection of the occupants and battery of an electric vehicle in the event of a side impact against an obstacle such as a pole. The invention further relates to the protection of the perimeter of the rolling base structure of motor vehicles.

[0002] Battery electrical modules must be protected against impact because damaging the high-voltage components can generate serious fires. This patent application relates more specifically to lateral impact (also known as "pole impact") because it is particularly severe in terms of intrusion into the battery platform, and therefore lateral impact on the battery.

[0003] For this reason, an electric car underbody is reinforced by two types of load paths illustrated in Figures 1 and 2: - laterally oriented TA base cross members, directly assembled on the floor P (already existing on known thermal vehicles); - Laterally oriented TM inter-module crossbeams, arranged between the modules, the assembly of which depends on the architecture.

[0004] Unfortunately, the load paths mentioned above prove insufficient to resist lateral impacts. Good impact resistance requires the additional involvement of the battery tray base as a major additional load path.

[0005] An objective of the present invention is to offer an improvement in the impact resistance of the battery tray base to limit the risk of fire in the event of a lateral impact on the traction battery.

[0006] To achieve this objective, the invention proposes a motor vehicle in a spatial frame of reference comprising a front-to-rear axis along a direction of movement of the motor vehicle, a lateral axis perpendicular to the front-to-rear axis, and a vertical axis perpendicular to the front-to-rear axis and to the lateral axis, the motor vehicle comprising a battery tray receiving battery modules of a traction battery, the battery tray comprising: - a floor delimiting the bottom of the battery tray in the lower part with reference to the vertical axis; - inter-module crossbeams arranged above the floor, extending laterally along the lateral axis between battery module positions; - lateral cross members extending in a front-to-back direction along the front-to-back axis, arranged at the lateral ends of the inter-module cross members with reference to the lateral axis, the inter-module cross members being attached to the lateral cross members.

[0007] Advantageously, the invention proposes joining all the transverse inter-module cross members of the tank base with lateral cross members to prevent the tank from folding downwards upon impact. Indeed, the lateral cross member absorbs energy in the event of a lateral impact and limits downward deformation of the tank base.

[0008] Furthermore, the invention also indirectly reduces the forces sent into the battery module mounting tabs.

[0009] Preferably, the inter-module cross members are welded to the lateral cross members.

[0010] This allows for a rigid connection of the inter-module cross members to the lateral cross members.

[0011] Preferably, the battery tray includes a front weld point and a rear weld point with reference to the front-rear axis, between each intermodule cross member and each lateral cross member.

[0012] This allows for front and rear mechanical reinforcement by these weld points.

[0013] Preferably, the battery tray further includes bottom cross members extending along the floor in a lateral direction along the lateral axis.

[0014] This allows for mechanical reinforcement of the floor.

[0015] Preferably, the battery tray comprises a tray frame which includes the side cross members attached to the inter-module cross members.

[0016] This makes it possible to offer such a ready-to-use structure without the need to implement welding steps.

[0017] Preferably, the battery tray further comprises base crossbeams delimiting the upper part of the battery tray with reference to the vertical axis, and extending above the inter-module crossbeams

[0018] This allows the top of the battery tray to be mechanically reinforced.

[0019] The invention further relates to a method for manufacturing a motor vehicle according to the invention, characterized in that it comprises the following steps: - a step of installing the inter-module crossbeams and the lateral crossbeams in which the inter-module crossbeams are placed above the floor, so that they extend laterally along the lateral axis between the battery module positions; and the lateral crossbeams are arranged so that they extend in a front-to-back direction along the front-to-back axis, at the lateral ends of the intermodule crossbeams with reference to the lateral axis; and - a joining step in which the inter-module crossbeams are joined to the lateral crossbeams.

[0020] Preferably, in the joining step, the inter-module cross members are welded to the lateral cross members.

[0021] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures, in which: - [Fig.l] schematically illustrates a view from below of the top of a battery tray of a vehicle according to the prior art, showing the inter-module cross members; - [[Fig.2]] schematically illustrates a top view of the floor of a battery tray of a vehicle according to the prior art, showing the support crossbeams; - [[Fig.3]] schematically illustrates a side section view along III-III of figures 1 and 2, showing the arrangements of the inter-module crossbeams, the lateral crossbeams and the base crossbeams; - [[Fig.4]] schematically illustrates a view in space of a battery tray of a vehicle according to the invention; - [[Fig.5]] schematically illustrates views in space of the impact of a side shock on a vehicle battery tray according to the prior art at the top, and according to the invention in the middle and at the bottom.

[0022] The invention relates to an electric motor vehicle comprising a mechanically reinforced battery tray. The vehicle and the battery tray are described with reference to a coordinate system in space comprising a front-to-back axis X along a direction of movement of the motor vehicle, a lateral axis Y perpendicular to the front-to-back axis X, and a vertical axis Z perpendicular to the front-to-back axis X and to the lateral axis Y.

[0023] The battery tray receives battery modules M from a traction battery, in use. These modules M can be fixed to it by means of fixing tabs (not shown).

[0024] The battery tray includes in its lower part a floor P delimiting the bottom of the battery tray with reference to the vertical axis Z.

[0025] The battery tray further includes inter-module crossbeams TM, and bottom crossbeams TF (illustrated in [Fig.4]), as well as base crossbeams TA.

[0026] The inter-module crossbeams TM are arranged above the floor P. They extend laterally along the lateral axis Y between battery module positions M.

[0027] The TA base cross members delimit the top of the battery tray in the upper part with reference to the vertical axis Z. They extend above the inter-module cross members TM.

[0028] The bottom cross members TF extend along the floor P in a lateral direction along the lateral axis Y.

[0029] The inter-module cross members TM, bottom members TF, and base members TA referred to above are illustrated in their arrangement in [Fig.3]. The reference ZL in this figure designates a longitudinal beam area where longitudinal beams (not shown) are arranged on either side of the battery tray.

[0030] According to the invention, the battery tray further comprises lateral cross members TL that mechanically reinforce the battery tray. Reference numeral ZT in [Fig. 3] illustrates the area where the lateral cross members TL are located.

[0031] The lateral cross members TL extend in a front-to-back direction along the front-to-back axis X. They are arranged at the lateral ends of the intermodule cross members TM with reference to the lateral axis Y.

[0032] Furthermore, according to the invention, the inter-module cross members TM are secured, in particular welded, to the lateral cross members TL. For this purpose, two weld points PA, PP are provided between the lateral cross member TL and the inter-module cross member TM. These are, in each case, a front weld point PA and a rear weld point PP with reference to the front-rear axis X, illustrated in [Fig.4].

[0033] These two added lateral TL cross members stiffen the "cell-to-body" type tank base. This is intended to replicate a tank base lining.

[0034] It is possible to use a single piece comprising the transverse TM and lateral TL inter-module cross members to form a skeleton-type tank bottom liner. This can be referred to as a tank frame comprising the lateral TL cross members attached to the TM inter-module cross members.

[0035] The invention further relates to a manufacturing process comprising steps for setting up and securing the elements discussed above.

[0036] In particular, the manufacturing process includes a step of installing the inter-module crossbeams TM and the lateral crossbeams TL. In this step, the inter-module crossbeams TM are positioned above the floor P, so that they extend laterally along the lateral axis Y between the battery module positions M. In addition, the lateral crossbeams TL are positioned so that they extend in a front-to-back direction along the front-to-back axis X, at the lateral ends of the inter-module crossbeams TM with respect to the lateral axis Y.

[0037] The manufacturing process further includes a step of joining the aforementioned cross members. In this step, the inter-module cross members TM are joined to the lateral cross members TL, preferably by the PA, PP weld points discussed above.

[0038] Figure 5 illustrates the effect of a lateral impact of a PL post against the battery tray. The figure above shows TF bottom cross members that are deformed by the lateral impact in the prior art.

[0039] The middle figure shows the same impact within the framework of the invention. In this case, the TF bottom cross members are not deformed by the lateral impact in the invention.

[0040] The figure below shows the interior of the battery tray after the lateral impact in the case of the invention. As can be seen in this figure, the TM inter-module cross members are also not deformed.

[0041] The invention allows for increased safety by protecting the battery in the event of a pole impact; as well as an optimization of the design in terms of mass / performance ratio in that the added parts rebalance the passages of force to make a better compromise between the mass of the parts and their mechanical resistance.

Claims

Demands

1. Motor vehicle in a frame of reference in space comprising a front-to-back axis (X) along a direction of movement of the motor vehicle, a lateral axis (Y) perpendicular to the front-to-back axis (X), and a vertical axis (Z) perpendicular to the front-to-back axis (X) and to the lateral axis (Y), the motor vehicle comprising a battery tray receiving battery modules (M) of a traction battery, the battery tray comprising: - a floor (P) delimiting the bottom of the battery tray in the lower part with reference to the vertical axis (Z); - inter-module cross members (TM) arranged above the floor (P), extending laterally along the lateral axis (Y) between positions of battery modules (M);- lateral cross members (TL) extending in a front-to-back direction along the front-to-back axis (X), arranged at the lateral ends of the inter-module cross members (TM) with reference to the lateral axis (Y), the inter-module cross members (TM) being fixed to the lateral cross members (TL).

2. Motor vehicle according to claim 1, characterized in that the inter-module cross members (TM) are welded to the lateral cross members (TL).

3. Motor vehicle according to claim 2, characterized in that the battery tray comprises a front weld point (PA) and a rear weld point (PP) with reference to the front-rear axis (X), between each inter-module cross member (TM) and each lateral cross member (TL).

4. Motor vehicle according to any one of claims 1 to 3, characterized in that the battery tray further comprises bottom cross members (TF) extending along the floor (P) in a lateral direction along the lateral axis (Y).

5. Motor vehicle according to any one of claims 1 to 4, characterized in that the battery tray comprises a tray frame which includes the side cross members (TL) attached to the inter-module cross members (TM).

6. A motor vehicle according to any one of claims 1 to 5, characterized in that the battery tray further comprises seat cross members (TA) delimiting the top of the battery tray by upper part in reference to the vertical axis (Z), and extending above the inter-module crossbeams (TM).

7. A method for manufacturing a motor vehicle according to any one of claims 1 to 6, characterized in that it comprises the following steps: - a step of setting up the inter-module cross members (TM) and the side cross members (TL) in which the inter-module cross members (TM) are placed above the floor (P), so that they extend laterally along the lateral axis (Y) between the battery module positions (M); and the side cross members (TL) are placed so that they extend in a front-to-back direction along the front-to-back axis (X), at the lateral ends of the inter-module cross members (TM) with reference to the lateral axis (Y); and - a step of joining in which the inter-module cross members (TM) are joined to the side cross members (TL).

8. Manufacturing method according to claim 7, characterized in that in the joining step, the inter-module cross members (TM) are welded to the lateral cross members (TL).

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