Electric motor vehicle comprising a load-bearing underbody incorporating the battery

Abstract

The invention relates to an electric motor vehicle comprising: a traction motor drive unit (32); and a traction battery (20) arranged beneath the floor of the passenger compartment of the vehicle and comprising modules (22) forming rigid assemblies, the vehicle also comprising a load-bearing underbody that forms a flat subassembly including the battery modules (22) and comprises a transversely-arranged elongate interface structure (24) which provides a front connection between the underbody and the vehicle body and a connection to the motor drive unit (32) and which is secured to the front faces (60) of the battery modules (22), and a rear crossmember (100) secured to the modules (22) and providing a rear connection between the underbody and the vehicle body.

Description

[0001] DESCRIPTION

[0002] TITLE: ELECTRIC MOTOR VEHICLE WITH A LOAD-BEARING UNDERFRAMING INTEGRATING THE BATTERY

[0003] The present invention claims priority from French application No. FR2501218 filed on 06 / 02 / 2025, the content of which (text, drawings and claims) is incorporated herein by reference

[0004] 0001. The present invention relates to an electric motor vehicle comprising a load-bearing underbody integrating the battery, constituting with the powertrain a motorization unit, as well as a method for assembling such a vehicle.

[0005] 0002. A known type of electric vehicle, presented in particular by document CN-U-220904674, includes a battery forming a flat rectangular case which is fitted and fixed under the floor of the passenger compartment between two longitudinal members forming a subframe of the vehicle body, which extends into a front cradle receiving the powertrain.

[0006] 0003. Another known type of electric vehicle, presented in particular by document US-A1-20220289067, has two traction battery modules arranged flat between the two side members of a vehicle chassis forming a subframe separate from the vehicle body.

[0007] 0004. For these two types of vehicles, the traction battery forms a separate unit fixed under the body, which is separate from the other motorization equipment including the electric powertrain, and housings containing the electronic systems which in particular control the powertrain, manage the battery and recharge from an electricity distribution network.

[0008] 0005. This results in a juxtaposition of systems, each requiring rigid and watertight enclosures, system mountings, electrical connection cables with end connectors, and heat exchange fluid pipes between them. The enclosures required for each system and the intermediate clearances between these elements result in a significant volume, which is taken up, in particular, at the expense of the space available for the electrochemical cells that provide the vehicle's autonomy. 0006. Furthermore, the number of components used adds mass to the vehicle and increases manufacturing costs and assembly labor time, which must be factored into the vehicle's cost price.Furthermore, the various systems fixed in the vehicle independently of the battery do not allow for the creation of a complete motorization assembly prepared to receive the vehicle body in order to facilitate its assembly.

[0009] 0007. The present invention is specifically designed to avoid these problems of the prior art.

[0010] 0008. It proposes for this purpose an electric motor vehicle comprising a traction electromotor unit, and a traction battery disposed under the floor of the vehicle's passenger compartment, comprising modules forming rigid assemblies, this vehicle being remarkable in that it comprises a load-bearing underbody forming a flat sub-assembly comprising the battery modules, comprising an elongated interface structure disposed transversely, ensuring a front connection of the underbody with the vehicle body and a connection with the electromotor unit, which is fixed on the front faces of the battery modules, and comprising a rear crossmember fixed to the modules ensuring a rear connection of the underbody with the vehicle body.

[0011] 0009. One advantage of this vehicle is that by using battery modules forming resistant housings, completed at the front by the transverse interface structure, and by the rear crossmember, a load-bearing platform is created that can withstand mechanical stresses, in particular to form the links with the electromotor group and to support housings of electronic systems.

[0012] 0010. In this way, the number of additional components needed to fix all these elements to the vehicle body is limited, which increases the volume available for the implantation of the battery's electrochemical cells, reduces the total mass and decreases the manufacturing and assembly costs of the vehicle.

[0013] 0011. The vehicle according to the invention may further comprise one or more of the following features, which may be combined with each other. 0012. Advantageously, the battery modules each comprise a stack of electrochemical cells in flat pockets which is held tightly in a frame.

[0014] 0013. In this case, advantageously the interface structure comprises two housings facing the rear of the vehicle, each receiving the front face of a module which is fitted and fixed inside.

[0015] 0014. Advantageously, the front face of each module has electrical connectors and coolant connectors, which fit onto corresponding connectors of the interface structure during subassembly.

[0016] 0015. Advantageously, the interface structure has fixings under the vehicle body protruding from its ends, and forward connections with the powertrain.

[0017] 0016. Advantageously, the interface structure includes electronic battery management systems.

[0018] 0017. Advantageously, the vehicle includes electronic system housings comprising battery and electro-motor management functions, which are fixed on top of the interface structure.

[0019] 0018. In this case, in particular the vehicle may include a first electronic systems housing placed directly on the transverse interface structure, and a second electronic systems housing placed on top of the first housing and extending forward over the powertrain.

[0020] 0019. In particular, the rear faces of the electronic system housings can directly form the front wall of the passenger compartment.

[0021] 0020. The invention also relates to a method of assembling a motor vehicle comprising any one of the preceding characteristics, remarkable in that it includes a step of preparing a motorization assembly comprising the supporting underbody, the electro-motor unit, electronic system housings fixed on the interface structure, and ground connection devices fixed on this underbody, and then a step of fixing this assembly under the body of the vehicle.

[0022] 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: 0022. [Fig. 1] is a diagram of an electric vehicle according to

[0023] the invention comprising a battery formed of two modules;

[0024] 0023. [Fig. 2] shows the base of the body of this vehicle;

[0025] 0024. [Fig. 3] shows the assembled motorization unit of this vehicle including the integrated battery;

[0026] 0025. [Fig. 4] is a rear view of the interface structure;

[0027] 0026. [Fig. 5] is a view of a complete battery module;

[0028] 0027. [Fig. 6] is a detailed view of the electrical connections in a module;

[0029] 0028. [Fig. 7] is a top view diagram of the electrical connections of the two modules with the transverse interface structure;

[0030] 0029. [Fig. 8] shows the rigid clamping frame of a battery module; 0030. [Fig. 9] shows a cooler placed on the cell stack; 0031. [Fig. 10] is a rear view of the module showing the venting gas outlet;

[0031] 0032. [Fig. 11] is a view of the battery showing the rear crossmember for attachment to the vehicle body; and

[0032] 0033. [Fig. 12] shows the assembly of the body on the motor assembly.

[0033] 0034. Throughout the document the upper or top direction is relative to a vehicle placed on a horizontal ground, the transverse direction is perpendicular to the longitudinal axis of the vehicle, the front direction AV is relative to its direction of travel.

[0034] 0035. Figures 1 and 2 show an electric vehicle having a body underbody comprising two side rails 4 connected by two seat support cross members 6 fixed above, which are arranged between the front axle 8 and the rear axle 10.

[0035] 0036. On each side of the vehicle, a body pillar 12 fixed to the front end of the longitudinal member 4 receives a profile 16 turned towards the front which is arranged along the engine compartment to support the powertrain 32. A top cross member 14 connects the top of the body pillars 12 to stiffen them.

[0036] 0037. Figure 3 shows the complete motorization assembly including a flat battery 20 fixed under the passenger compartment, formed by two rigid rectangular modules 22 arranged parallel along the longitudinal direction, comprising a front face which is fixed on a low transverse interface structure 24.

[0037] 0038. A lower cross member 26 fixed under the interface structure 24 by reinforcing this structure, has on each side a projecting end 42 for fixing under the body pillar 12, and a projecting front edge 44 which receives two rear elastic links 36 of the powertrain 32 equipped with wheel shafts 34 driving the wheels of the front axle 8. A front bumper cross member 40 arranged in front of the engine compartment receives two front elastic links 38 of the powertrain 32.

[0038] 0039. A lower electronic housing 28 fixed above the interface structure 24, substantially covering its surface, receives above it an upper electronic housing 30 protruding forward above the powertrain 32.

[0039] 0040. The aligned rear faces of the lower housing 28 and the upper housing 30, positioned in front of the vehicle's passenger compartment, form a firewall above the battery 20, separating the passenger compartment from the engine compartment. These rear faces of the housings 28 and 30 can also serve as supports for the pedal assembly located in front of the driver.

[0040] 0041. A flat rear chassis 46 fixed under the vehicle body behind the battery 20, forms a rectangular frame receiving inside a rear powertrain 48 having wheel shafts 34 driving the wheels of the rear axle 10, which is fixed to this frame by two front elastic links 38 and two rear elastic links 36.

[0041] 0042. Advantageously the interface structure 24 contains the electronic battery management system “BMS”, called “Battery management system” in English, and the electronic motor power unit “PDU”, called “Power drive unit” in English.

[0042] 0043. The lower electronic housing 28 contains a reversible battery charger "IDCM", called "Integrated Dual Charging Mode" in English. The upper electronic housing 30 contains the powertrain thermal control system and the passenger compartment heating, ventilation, and air conditioning (HVAC) system. In this way, all the electronic functions are grouped within the powertrain assembly. 0044. Figures 4 and 5 show the front face 60 of a battery module 22 comprising a contour 62 slightly recessed from the contour of this module, which fits into one of the two rectangular recesses 50 on the rear face of the interface structure 24 so as to form the outer surfaces of the structure and the modules, which extend from one another.The interface structure 24 forms an intermediate resistant cross member fixed to the vehicle body, between towards the rear the lower flat part consisting of the battery 20, towards the front the powertrain 32, and above the electronic boxes 28, 30.

[0043] 0045. Each rectangular housing 50 has on each side a rectangular male electrical connector 52 and a circular male fluid connector 54, which fit respectively into a female electrical connector 64 and a female fluid connector 66 formed on the front face of module 60. In this way, when each module 22 is fitted onto the interface structure 24, which includes locking devices not shown, a rigid mechanical connection between these elements, a power electrical connection of the positive and negative poles, and a connection for the circulation of cooling fluid in this module are obtained.

[0044] 0046. The electrical connectors 52 transmit the electrical power from the battery 20, and make all the other necessary electrical connections to this battery.

[0045] 0047. Figures 6 and 7 show each module 22 comprising a set of stacked and tightly packed flat-pocket electrochemical cells 70, called "solid-state batteries," each consisting alternately of a cell and a slightly flexible intermediate plate that allows for slight swelling of the cell during charging. On each side of the stack, an electrical connection 72 links the positive terminal of one cell 70 to the negative terminal of the next cell, so as to arrange all the cells of a single module 22 in series.

[0046] 0048. In the interface structure 24 the common power supply 76 of the two modules 22 splits for each pole into two branches each supplying the male electrical connection 52 of a module, connecting it for one pole to the female electrical connection 64 arriving directly on that same pole of the first forward cell 80, and for the other pole after a longitudinal conductor 78 of that pole of the last rear cell 82.

[0047] 0049. Figure 8 shows the entire stack of cells 70 of a module 22 clamped on each side along the plates by two round tension rods 86, which pass through both a rear face 84 and the front face 60 having significant thicknesses to obtain rigidity in order to distribute the pressure over the entire surface of the plates.

[0048] 0050. Figure 9 shows a cooling duct 90 forming a plate covering all the cells 70 on top, having the two front female connectors 66 connected to the male connectors 54 of the interface structure 24 in order to obtain circulation in this plate connected to the powertrain circuit 32 which controls the temperature of all the cells.

[0049] 0051. Figure 10 shows the rear face 84 of each module 22, comprising in the middle a conduit 92 closed by a pressure limiting valve, called a "pressure release valve" in English, or

[0050] “PRV”, ensuring sealing, and allowing the evacuation of hot gases emitted by the cells during functional or dysfunctional degassing, called “venting gases” in English, towards the rear of the vehicle to avoid accidents.

[0051] 0052. A metal cover 94 made of folded sheet metal covers the whole of the module 22 by connecting the front face 60 and the rear face 84, which provides both protection for the cells 70 and adds rigidity to the module allowing it to form a load-bearing structure.

[0052] 0053. Figure 11 shows a rear cross member 100 connecting the two modules 22, comprising a lower flat part coming under the two modules, the ends of which are fixed under the body, a rear folded rim rising 102 to form a rear wedge for the modules, and an intermediate hollow profile 104 wedged between the two modules to keep them tight in width, which is fixed from above under the body of the vehicle.

[0053] 0054. The vehicle assembly process involves the production of a complete powertrain assembly, shown in Figure 3, which is held on a platform (not shown) allowing it to move to the various workstations of an assembly line, comprising the following steps. 0055. The two modules 22 are connected together by attaching the interface structure 24 at the front and the rear connecting plate 100 at the rear, thus forming a rigid, load-bearing structured underbody. The front bumper crossmember 40, the rear chassis 46, the suspension components (including the wheel hubs and suspensions, not shown), and the two powertrains 32, 48, secured by their elastic connections 36, 38, are then attached around this underbody. The various electronic control units 28, 30 are then added to the interface structure 24.

[0054] 0056. We obtain a motorization assembly which groups together around a structured load-bearing base all the components necessary for the electric motorization, including the battery 20, the electric powertrains 32, 48, and all the electronic boxes as well as all the necessary wiring between them, which avoids adding external cables with their connectors.

[0055] 0057. Figure 12 describes the lowering of the vehicle body shown only by its base, onto the motor assembly to perform the assemblies between them.

[0056] 0058. Preparing a separate motor assembly from the body allows, after assembly, for testing and trials to be carried out on this assembly, which includes all the electrical components necessary for traction, in working order. This facilitates validation and any necessary adjustments. This motor assembly also allows for complete removal from the body in the event of any work on the motor, providing access to all integrated components.

Claims

DEMANDS 1. Electric motor vehicle comprising a traction electromotor unit (32), and a traction battery (20) disposed under the floor of the vehicle passenger compartment, comprising modules (22) forming rigid assemblies, characterized in that it comprises a load-bearing underframe forming a flat sub-assembly comprising the battery modules (22), comprising an elongated interface structure (24) disposed transversely, ensuring a front connection of the underframe with the vehicle body and a connection with the electromotor unit (32), which is fixed to the front faces (60) of the battery modules (22), and comprising a rear crossmember (100) fixed to the modules (22) ensuring a rear connection of the underframe with the vehicle body.

2. Motor vehicle according to claim 1, characterized in that the battery modules (22) each comprise a stack of electrochemical cells in flat pockets (70) which is held tightly in a frame.

3. Motor vehicle according to claim 1 or 2, characterized in that the interface structure (24) comprises two housings (50) facing the rear of the vehicle, each receiving the front face (60) of a module (22) which is fitted and fixed into it.

4. Motor vehicle according to any one of the preceding claims, characterized in that the front face (60) of each module (22) has electrical connectors (64) and coolant connectors (66), which fit onto corresponding connectors (52, 54) of the interface structure (24) during assembly of the subassembly.

5. Motor vehicle according to any one of the preceding claims, characterized in that the interface structure (24) has fixings under the vehicle body protruding from its ends (42), and forwards links (36) with the powertrain (32).

6. Motor vehicle according to any one of the preceding claims, characterized in that the interface structure (24) includes within it electronic battery management systems (20).

7. Motor vehicle according to any one of the preceding claims, characterized in that it includes electronic system housings (28, 30) comprising battery (20) and electro-motor unit (32) management functions, which are fixed on top of the interface structure (24).

8. Motor vehicle according to claim 7, characterized in that it comprises a first electronic systems housing (28) placed directly on the transverse interface structure (24), and a second electronic systems housing (30) placed above the first housing (28) and extending forward above the powertrain (32).

9. Motor vehicle according to claim 7 or 8, characterized in that the rear faces of the electronic system housings (28, 30) directly form the front wall of the passenger compartment.

10. Method of assembling a motor vehicle according to any one of the preceding claims, characterized in that it comprises a step of preparing a motorization assembly including the supporting underbody, the electric motor unit (32), electronic system housings (28, 30) fixed on the interface structure (24), and ground connection devices fixed on this underbody, and then a step of fixing this assembly under the body of the vehicle.

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