Chassis for a motor vehicle battery pack incorporating cooling circuit pipes and battery pack comprising such a chassis

Abstract

The invention relates to a chassis for a motor vehicle battery pack comprising a rectangular frame comprising two side members (111) consisting of extruded metal profiles each having at least one internal cavity (CPSE2) forming a circulation pipe for the liquid cooling circuit of the battery pack, each said side member further having at least one transverse bore (APSE) produced after the extrusion process from one of its side walls and opening into said pipe, each said bore being in fluid communication with a corresponding connection member (170) fixedly attached to a said side member and provided with a sleeve (172) projecting from this side member, each said connection member also comprising a plate (171) having a bore in fluid communication with said sleeve, said plate being fixedly and tightly attached, by its face opposite said sleeve,against a side wall of a said spar on the periphery of a said bore. Figure to be published with the abstract: Fig. 7,

Description

Title of the invention: Chassis for a motor vehicle battery pack incorporating cooling circuit pipes and battery pack comprising such a chassis Technical field

[0001] The present invention relates to electrically powered motor vehicles equipped with a propulsion battery pack. It relates in particular to a chassis for such a motor vehicle battery pack. Prior art

[0002] Electrically powered motor vehicles are becoming increasingly popular due to their reduced environmental impact, often lower operating costs, and continued advances in battery technology, improving the range and performance of electric vehicles.

[0003] Public awareness campaigns on the environmental and economic benefits of this technology, as well as traffic restrictions implemented in many urban areas, are also encouraging owners of motor vehicles with internal combustion engines to convert them to electric vehicles by integrating an electric powertrain and a battery to replace the thermal engine and fuel tank.

[0004] Such a conversion, commonly referred to as an “automotive retrofit”, allows owners of older vehicles to continue to use them in regulated low-emission zones (LEZs) while benefiting from the advantages of electric propulsion, such as reduced emissions, lower fuel costs, and often simpler maintenance.

[0005] The propulsion battery of an electrically powered motor vehicle conventionally comprises several battery modules, each comprising a plurality of electrochemical cells capable of generating current by chemical reaction (these cells may, for example, be of the Li-ion type, of the Ni-Mh type, or even Ni-Cd).

[0006] These battery modules are mounted on a chassis to form a battery pack, more commonly referred to by the English expression "battery pack", and commonly installed fixedly under the underbody of the vehicle so as not to impact the habitability of this vehicle while ensuring sufficient autonomy. Such an installation is also often mandatory for vehicles converted to electric propulsion known as "retrofitted", for which structural modifications must be limited both for reasons of cost and approval.

[0007] Having to be able to withstand very significant mechanical forces simulating frontal, rear or lateral collisions (in particular compliance with longitudinal and transverse deflection criteria) in order to avoid any risk of short circuit or electrolyte leakage, the chassis of these battery packs may comprise an external frame made from several hollow profiled elements made by an extrusion process in a metal alloy (for example based on aluminium) and assembled to each other by welding at their ends.

[0008] Commonly used in electric vehicles, lithium-ion battery modules can overheat when subjected to fast charging conditions or high ambient temperatures.

[0009] To control the temperature of these battery modules, most battery packs installed in motor vehicles incorporate a cooling system in which a heat transfer fluid, generally water or a mixture of water and glycol, circulates through a cooling circuit. This liquid absorbs, via exchanger devices, for example of the “cold plate” type, arranged in contact with these battery modules, part of the heat generated by these modules and transports it to another exchanger device in the vehicle allowing it to be cooled by transferring part of its heat to another cooling circuit, such as that of the vehicle’s air conditioning system, to be dissipated into the ambient air.

[0010] Such a cooling circuit is conventionally made up of an assembly of several hot-formed semi-rigid pipes, arranged on the periphery of the chassis, and extending along the underbody of the vehicle.

[0011] The installation of these pipes often proves problematic since they generally have to follow a tortuous route allowing them to bypass certain constituent elements of the vehicle installed on this underbody.

[0012] Furthermore, these pipes must be fixed to this body underbody at several points by anchoring clips, which also contributes to complicating the operations of installing the battery pack.

[0013] In order to overcome these problems, it is known from document DE 10 2020 101 018 A1 that the two extruded metal profiles constituting the side members of the outer frame of the chassis each have at least one internal cavity forming a circulation pipe for the cooling circuit of the battery pack and the internal surface of which is covered with a thermally insulating layer.

[0014] Each spar further has at least one transverse bore made after the extrusion process from one of its side walls and passing through a lateral interior cavity of this spar before opening into this central interior cavity forming a circulation pipe.

[0015] In each bore is further fixedly inserted (by force, by gluing and / or screwing) a connecting member provided with a sleeve projecting from the corresponding spar and allowing a pipe to be fluidically connected to it.

[0016] Unfortunately, due to the low thickness of material passed through by each connecting member, the quality of the fixing proves insufficient to guarantee perfect sealing over time. Statement of the invention

[0017] The present invention therefore aims to improve the situation.

[0018] To this end, it proposes a chassis for a motor vehicle battery pack comprising a rectangular frame formed of two longitudinal side members and two transverse cross members fixed to each other at their ends, said side members being constituted by extruded metal profiles each having at least one internal cavity forming a circulation pipe for the liquid cooling circuit of the battery pack.

[0019] Each said spar further has at least one transverse bore made after the extrusion process from one of its side walls and opening into said circulation pipe, each said bore being in fluid communication with a corresponding connection member fixedly attached to a said spar and provided with a sleeve projecting from this spar so as to allow a pipe to be fluidically connected thereto.

[0020] According to the invention, each said connecting member also comprises a plate having a bore in fluid communication with said sleeve, said plate being fixedly and tightly attached, by its face opposite said sleeve, against a side wall of a said spar on the periphery of a said bore.

[0021] The use of connection members equipped with such a plate makes it possible to obtain better quality of fixing and sealing of these connection members to the spar and to very significantly limit the risks of leakage of the heat transfer liquid circulating in these circulation pipes.

[0022] According to a first preferred embodiment of the invention, said plate of each said connecting member is fixedly attached by screwing onto a said side wall of a said spar, by means of screws passing through orifices provided in said plate and screwing into corresponding tapped holes provided in said side wall of a said spar.

[0023] According to an advantageous construction associated with this first embodiment and making it possible to limit the mass of the chassis, said screws advantageously open inside two other internal cavities provided in each said side member respectively above and below said circulation pipe.

[0024] In order to ensure perfect sealing between each connecting member and the corresponding spar according to this first embodiment, said plate of each said connecting member advantageously has, on its face opposite said sleeve and on the periphery of said drilling, an annular groove partially housing a sealing joint coming into compression against said side wall of a said spar.

[0025] According to a second preferred embodiment of the invention, said plate of each said connecting member is fixedly attached by welding to a said side wall of a said side member, by means of a weld bead.

[0026] In order to ensure perfect sealing between each connecting member and the corresponding spar according to this second embodiment, said weld bead advantageously extends continuously around the entire peripheral periphery of said drilling.

[0027] In order to better preserve the original mechanical resistance characteristics of the welded materials, said weld bead is preferably produced by a friction stir welding process.

[0028] Generally speaking and in order to limit production costs, said sleeve of each said connecting member advantageously comes from a single block with said plate of this connecting member.

[0029] Alternatively and so as to allow the use of different types of sleeves depending on the characteristics of the connecting tips which are connected thereto, said sleeve and said plate of each said connecting member can be constituted by two separate parts, said sleeve being fixedly and tightly attached by screwing onto said bore of said plate which is tapped.

[0030] In this case and in order to have a satisfactory screwing depth, the central zone of said plate in which said tapped hole is formed advantageously has a thickness greater than that of its peripheral zone.

[0031] According to an advantageous conformation, a fluid connection end piece is fixedly and tightly attached to a first end of said circulation pipe of each said spar, while a plug is fixedly and tightly attached to the second end of said circulation pipe of each said spar.

[0032] In order to limit heat losses, the inner surface of each said circulation pipe may be covered with a thermally insulating layer.

[0033] According to an advantageous construction ensuring excellent shock absorption, said side members and said cross members are made up of metal profiles of the same section, each comprising: - an upper sealing portion extending vertically and in which said circulation pipe is arranged, this upper sealing portion having an upper face designed to receive the perimeter in a sealed manner peripheral of an upper cover of said battery pack; and - a connection portion extending below said upper sealing portion, projecting laterally on either side of the latter, respectively from an external lateral overhang and an internal lateral overhang on which are respectively intended to be fixed attachment supports to the underbody of said vehicle and battery modules.

[0034] In order to protect the battery pack in the event, for example, of the vehicle being lifted with a rolling jack resting on the chassis frame or even when the vehicle is crossing or descending pavements, each said profile may also advantageously comprise a lower ground clearance portion extending vertically below said connection portion.

[0035] The invention also relates, in a second aspect, to a battery pack intended to be fixedly installed against the underbody of a motor vehicle, said battery pack comprising such a chassis, several battery modules mounted on said chassis and a cooling subassembly comprising a liquid cooling circuit in which a heat transfer fluid circulates as well as several exchanger devices each provided with inlet nozzles and outlet nozzles. Each said inlet nozzle, respectively outlet nozzle, is furthermore fluidically connected to said sleeve of a said respective connection member fixed to a first, respectively second, said side member by means of a corresponding connecting pipe.

[0036] Finally, the invention aims, in a third aspect, at a motor vehicle comprising such a battery pack. Brief description of the drawings

[0037] The description of the invention will now be continued by the detailed description of several exemplary embodiments, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l] represents an exploded perspective view of a battery pack for a motor vehicle comprising a chassis according to the invention; - [Fig.2] is a top view in assembled configuration of the battery pack of [Fig.l], in which certain elements including the top cover have been omitted in order to facilitate reading; - [Fig.3] represents a view of the section of the profiled elements constituting the frame of the chassis of figures 1 and 2; - [[Fig.4]] is a sectional view of the front end portion of the chassis of Figures 1 and 2, taken along the vertical longitudinal plane EE of [Fig.2]; - [Fig.5] represents a sectional view of the rear end portion of the chassis of figures 1 and 2, taken along the vertical longitudinal plane EE of [Fig.2]; - [Fig.6] is a sectional view of the central portion of the chassis of figures 1 and 2, taken along the vertical longitudinal plane EE of [Fig.2]; - [Fig.7] represents a sectional view of the left lateral portion of the chassis of figures 1 and 2, taken along the vertical transverse plane FF of [Fig.2]; - [[Fig.8]] is a perspective view of the connection zone between an outlet nozzle of an exchanger device and the internal circulation pipe of a side member of the chassis of figures 1 and 2; - [Fig.9] represents a perspective view of one of the connecting members screwed to the frame side members of the chassis of figures 1 and 2; - [[Fig. 10]] is a perspective view of a screwed connection member according to an alternative embodiment; - [Fig. 11] and [Fig. 12] represent views similar to those of figures 7 and 8 but showing a chassis according to the invention whose connecting members are welded to the side members of the frame; - [Fig. 13] is a perspective view of one of the connecting members welded to the frame side members of the chassis of Figures 11 and 12; and - [Fig. 14] is a perspective view of a welded connection member according to an alternative embodiment. Description of the embodiments

[0038] Figures 1 and 2 represent a battery pack 1 intended to be installed under the underbody of a motor vehicle (not shown), in particular in the context of the installation of an electrification kit for this vehicle.

[0039] We define with respect to this battery pack 1 an orthogonal reference frame XYZ comprising three axes perpendicular two by two, namely: - an X axis, defining a longitudinal, horizontal direction, parallel to the ground and coincident with the general direction of movement of the vehicle - a Y axis, defining a transverse, horizontal direction, also parallel to the ground and which with the X axis defines a horizontal XY plane, and - a Z axis, defining a vertical direction, perpendicular to the ground as well as to the horizontal XY plane.

[0040] In the remainder of the description and with reference to the reference defined above, the terms “longitudinal” or “longitudinally” will refer to a direction parallel to the X axis, the terms “transverse” or “transversely” will refer to a direction parallel to the Y axis, and the terms “vertical” or “vertically” will refer to a direction parallel to the Z axis.

[0041] On the other hand and by convention, the terms “lower”, “upper”, “front” and “rear” will be understood in relation to the general orientation of the battery pack 1 in its configuration mounted on a vehicle. The terms "lower" and "lower" will indicate a closer proximity to the ground in the vertical direction than the terms "upper" or "high." The term "front" will indicate a positioning oriented towards the front of a vehicle in the horizontal direction and the term "rear" will indicate a positioning oriented towards the rear of a vehicle in the same horizontal direction.

[0042] The terms “external” and “internal” will be used to define the relative position of an element with reference to the median vertical longitudinal plane of the battery pack 1. The element closest to this plane will thus be described as internal as opposed to the other element further from this same plane which will be described as external.

[0043] With reference to figures 1 and 2, the battery pack 1 comprises: - a chassis 100 according to the invention defining an internal volume Vi and which will be described in more detail later; - several battery modules 200 fixedly mounted on this chassis 100; - a cooling subassembly comprising a liquid cooling circuit in which a heat transfer liquid circulates, generally water or a mixture of water and glycol, as well as several exchanger devices 300 each fixedly attached to the lower face of a corresponding battery module 200; - a 400 power electronics box; - a 500 support bridge carrying this 400 power electronic box; - several electronic control systems 600 of the battery modules 200; - several rigid electrical connection braids 700 ensuring the high voltage electrical connection between the battery modules 200 and the power electronics box 400; - an upper cover 800 covering the battery modules 200, the power electronics box 400 as well as the electronic control systems 600; - at least one 900 electrical connection socket; and - two rectangular lower half-floors 1000 extending below the battery modules 200.

[0044] Housed in the internal volume Vi of the chassis 100, the battery modules 200, in this case two in number, each comprise a plurality of electrochemical cells capable of generating current by chemical reaction.

[0045] Each exchanger device 300, in this case of the cold plate type, comprises a metal plate 310 arranged in thermal contact with the lower face of a corresponding battery module 200 and covering a coil 320 in which a cooling liquid circulates intended to absorb and dissipate the heat generated by this battery module 200.

[0046] Each coil 320 is provided with an inlet nozzle 321 and an outlet nozzle 322 projecting vertically above the corresponding plate 310 near one of its transverse edges.

[0047] The power electronics box 400 integrates electronic components, such as inverters, to convert the electrical energy stored in the battery modules 200 into a form usable by the electric powertrain of the vehicle.

[0048] As illustrated by [Fig. 1], the support bridge 500 comprises two lateral legs 510 fixed by bolting to the internal lateral parts of the chassis 100 as well as an apron 520 overhanging the battery modules 200 and on which the power box 400 is fixed so as to keep it away from these battery modules 200.

[0049] Commonly referred to by the English acronym BMS for “Battery Management System”, the electronic control systems 600 ensure the balancing of the charges of all the cells of the same battery pack 200 in order to prevent undervoltages or overvoltages.

[0050] Intended to ensure the electrical connection between the battery pack and the electric powertrain of the vehicle, the electrical connection socket(s) 900 are fixedly attached against an external longitudinal end wall of the chassis 100.

[0051] Finally, the two half-floors 1000 made from cut sheet metal are fixedly attached in a sealed manner against the chassis 100, each below a corresponding battery module 200 so as to protect it.

[0052] The chassis according to the invention 100 will now be described in detail with reference to FIGS. 1 to 3.

[0053] The chassis 100 comprises a rectangular metal frame 110 formed of two longitudinal side members 111 and two transverse cross members 112 fixed to each other by welding at their ends.

[0054] As can be seen in particular in Figures 1 and 2, the side members 111 and the cross members 112 forming this frame 110 are made up of metal profiles having an identical P profile in section (see [Fig.3]) and obtained by a mechanical extrusion process from the same die.

[0055] With reference to this [Fig. 3], each profile 111, 112 comprises an upper sealing portion PSE oriented vertically and having an upper face FPSE against which the peripheral periphery of the cover 800 is fixedly attached (typically by screwing or by welding) and in a sealed manner (this sealing being able to be obtained by means of a peripheral seal or a joint bead not shown and interposed between this upper face FpSE and this cover 800).

[0056] The upper sealing portion PSE comprises an outer casing of rectangular section Epse forming its outer profile, as well as three in- cavities CPSEi, CPSE2, CPSE3 arranged one above the other.

[0057] Advantageously having a circular section, the internal cavity CPSE2 is arranged in the central zone of this upper sealing portion PSE between the two other upper cavities CPSEi and lower CPSE3 arranged respectively above and below the latter.

[0058] The internal cavity CPSE2 of each side member 111 further forms a circulation pipe for the cooling circuit of the cooling subassembly arranged to ensure the circulation of a heat transfer liquid along the chassis 100.

[0059] As illustrated by [Fig.6], the upper sealing portion PSE of each spar 111 has several transverse bores APSE (in this case, two arranged in its central portion) produced after the extrusion process from its internal side wall and opening into its circulation pipe CPSE2-

[0060] These transverse bores APSE are intended, as will be seen in more detail later, to allow the fluidic connection of the inlet nozzles 321 and outlet nozzles 322 of the exchanger devices 300 to these circulation pipes CPSE2-

[0061] Again with reference to [Fig. 3], each profile 111, 112 also comprises a connection portion PC oriented horizontally and extending below the upper sealing portion PSE, projecting laterally on either side of the latter, respectively with an external lateral overhang DEPC and an internal lateral overhang DIPC, preferably symmetrically identical with respect to the median vertical plane of the upper sealing portion PSE.

[0062] This connection portion PC is intended, on the one hand, to absorb the majority of the energy generated in the event of a collision in a longitudinal or transverse direction, and on the other hand to allow the battery modules 200 to be fixed to the frame 110 as well as the cross members 112 of this frame 110 directly to structural elements of the underbody of the vehicle.

[0063] The connection portion PC comprises an outer casing EPC forming its outer profile and having in section a beveled rectangle shape whose two lower lateral vertices are constituted by two inclined planes PPC forming with the horizontal an angle of inclination 0 advantageously between 15° and 30°. The presence of such inclined planes PPC makes it possible in particular to redirect, in the event of a collision in a longitudinal or transverse direction, a part of the longitudinal or transverse bending forces undergone by the profiles 111, 112 forming the frame 110 towards the lower part of this frame 110.

[0064] This PC connection portion also advantageously comprises at least one flat reinforcing rib extending between two opposite walls of the EPC outer envelope so as to delimit several cavities inside this EPC outer envelope.

[0065] The presence of such reinforcing ribs makes it possible to improve the mechanical resistance of this PC connection portion in the event of a collision in a longitudinal or transverse direction, so as to limit its bending curvature (these reinforcing ribs then absorbing part of the impact energy).

[0066] Such a structure thus makes it possible to limit the mass of the PC connection portion while allowing it to have excellent mechanical resistance.

[0067] In this case and as illustrated by [Fig. 3], the connection portion PC comprises a horizontal reinforcing flat rib NHPC extending at its median horizontal plane between the two vertical lateral panels of the outer envelope EPC, as well as two other vertical reinforcing flat ribs, respectively internal NVIPC and external NVEPC, extending vertically between the upper and lower panels (advantageously at the intersections between the lower panel and the two inclined panels PPC) and laterally on either side of the upper sealing portion PSE, so as to delimit six cavities inside this outer envelope EPC.

[0068] As can be seen in particular in Figures 1 and 2, the external overhangs DEPC of the side members 111 are provided with bores crossed by hollow attachment studs 120 welded around the perimeter of these bores and intended to ensure the fixing by bolting on the frame 110 of attachment supports not shown and making it possible to rigidly fix the battery pack 1 against the underbody of the vehicle.

[0069] Still with reference to these figures 1 and 2, the external overhangs DEPC of the crosspieces 112 are also provided with bores crossed by hollow attachment studs 120 welded around the perimeter of these bores and intended to ensure the fixing by bolting of these crosspieces 112 directly onto structural elements of the underbody of the vehicle.

[0070] As can be seen in particular in Figures 1 and 2, the internal overhangs DIPC of the crosspieces 112 are provided with bores on which nuts are crimped to ensure the fixing by bolting to the chassis 100 of a first longitudinal end of the battery modules 200 using screws.

[0071] Again with reference to [Fig.3], each profile 111, 112 finally comprises a lower ground clearance portion PGS extending vertically below the connection portion PC.

[0072] This lower portion of ground clearance PGS comprises an outer casing of rectangular section EPGS forming its outer profile and defining an inner cavity. In this case, it is devoid of a reinforcing rib.

[0073] The presence of such a lower portion of ground clearance PGS makes it possible to protect the battery pack 1 (in particular the battery modules 200 and certain other sensitive elements such as the coils of the exchanger devices 300 and the electrical power supply harnesses) in the event, for example, of the vehicle being lifted with a jack. roller leaning on the frame 110 of the chassis 100 or even when the vehicle crosses or descends sidewalks.

[0074] As illustrated by Figures 1 and 2, the ends 111A, 112A of the side members 111 and the cross members 112 are machined to fit together by complementary shape so as to allow them to be welded.

[0075] More precisely, the internal lateral wall of the upper sealing portion PSE of each machined end 11 IA of a spar 111 is assembled along a vertical longitudinal welding plane with the edge of the upper sealing portion PSE of the corresponding machined end 112A of a cross member 112.

[0076] Such a configuration makes it possible to achieve the sealed closure of the ends of these upper PSE sealing portions of the crosspieces 112 to which the electrical connection socket(s) 900 of the battery pack 1 are connected (such fluidic isolation of the upper PSE sealing portions of the crosspieces 112 from those of the side members 111 making it possible to avoid any risk of short circuit).

[0077] As illustrated by Figures 1 and 2, the chassis 100 also preferably comprises at least one metal reinforcing element 140 extending longitudinally or transversely inside the frame 110 between the two side members 111 or between the two ribs 112 of this frame to which its two ends are fixed by welding, so as to subdivide the internal volume Vi of the chassis 100 into several zones each housing at least one battery module 200.

[0078] This or these metal reinforcements 140 are advantageously constituted by metal profiles having in section the same profile P (cf. [Fig.3]) as that of the side members 111 and the cross members 112 of the frame 110, so as to reduce the cost of development and manufacture of the chassis 100 (use of a single extrusion die for the manufacture of all the profiles 111, 112 and 140 of this chassis 100).

[0079] In this case and as can be seen in Figures 1 and 2, the chassis 100 comprises a single reinforcement 140 extending transversely between the two central zones of the side members 111 of the frame, and subdividing the internal volume Vi of the chassis 100 into two zones each housing a battery module 200.

[0080] The internal DIPC and external DEPC overhangs of this transverse reinforcement 140 are provided with bores on which nuts 130 are crimped to ensure the fixing by bolting on the chassis 100 of the second longitudinal end of the battery modules 200.

[0081] It will also be noted with reference to Figures 1 and 8 that these internal DIPC and external DEPC overhangs of the transverse reinforcement 140 are provided with oblong passage notches 141 crossed by the inlet nozzles 321 and outlet nozzles 322 of the coils 320 of the exchanger devices 300.

[0082] It will also be noted that the four sides of the peripheral edge of the upper face of each rectangular half-floor 1000 are respectively fixedly and tightly attached by welding against the lower face of the internal overhang of a corresponding crosspiece 112, against the lower faces of the internal overhangs DI PC of the corresponding halves of the side members 111 and against the lower face of the internal overhang DIPC or external overhang DEPC of the transverse reinforcement 140, so as to fluidly isolate the battery modules 200 from water splashes.

[0083] As illustrated by figures 1 and 2, the ends 140A of the transverse reinforcement 140 are machined to fit together by complementary shape on the central zones of the two side members 111 of the frame 110, so as to allow them to be welded.

[0084] As can be seen in particular in [Fig. 4], a fluid connection end piece 150 is fixedly and tightly attached by screwing onto the threaded front end of the internal circulation pipe CPSE2 of each side member 111, these connection end pieces 150 being intended to be fluidly and tightly connected to coolant inlet and outlet pipes (not shown) connected to another exchanger device of the vehicle (not shown).

[0085] As illustrated in particular by [Fig.6], a plug 160 is fixedly attached in a sealed manner by screwing onto the threaded rear end of the internal circulation pipe CPSe2 of each side member 111.

[0086] The inlet nozzles 321 and outlet nozzles 322 of the different exchanger devices 300 are respectively fluidically connected to the internal circulation pipe C PSe2 of one and the other of the side members 111 by means of flexible connecting pipes 330 clearly visible in FIGS. 7 and 8.

[0087] The fluid connection between each connecting pipe 330 and the internal circulation pipe CPSE2 of a spar 111 is ensured by means of a fluid connection member 170 fixedly attached to the upper sealing portion PSE of this spar 111 at the level of a bore APSE with which it is in fluid communication.

[0088] Shown alone in [Fig.9], each fluid connection member 170 comprises a plate 171 (in this case, rectangular in shape) having in its central part a circular bore 171A, as well as a sleeve 172 projecting from one of the faces of this plate 171 from the periphery of this bore 171A with which it is in fluid communication.

[0089] As illustrated by figures 7 and 8, the plate 171 is fixedly and tightly attached, by its face opposite the sleeve 172, against the internal lateral wall of a spar 111 on the periphery of an APSE- bore.

[0090] Made from a single block with the plate 171, the sleeve 172 allows, such as illustrated by figures 7 and 8, to fluidly connect a corresponding flexible pipe 330 by means of a fluidic connection end piece 331 provided at one end of this pipe 330 and fitting onto this sleeve 172.

[0091] In order to ensure sealing between the bore 171A of each connecting member 170 and the corresponding bore APSE, the plate 171 has, on its face opposite the sleeve 172 and at the periphery of this bore 171A, an annular groove 171B partially housing a sealing O-ring 173 coming into compression against the internal lateral wall of the upper sealing portion PSE of a spar 111 on the periphery of this bore APSE (see [Fig.7]).

[0092] In order to allow its fixing by screwing to a spar 111, the plate 171 of each connecting member 170 has several orifices 171 C (in this case, four orifices arranged at the four corners of this plate) crossed by screws V which are screwed into corresponding tapped holes PT visible in [Fig. 6] and arranged in the internal lateral wall of the upper sealing portion PSE of a spar 111 at the level of the upper cavities CPSEi and lower CPSE3 (these screws V thus opening into the interior of these cavities CPSEi and CPSE3 as can be seen in [Fig. 7]).

[0093] [Fig. 10] illustrates an alternative embodiment of a screwed connection member 170' in which the sleeve 172' and the plate 171' are made up of two separate parts, the sleeve 172' being fixedly and tightly attached by screwing onto the bore 171'A of the plate 171' which is tapped.

[0094] In order to provide a sufficient screwing depth to ensure optimal fixing quality between the sleeve 172' and the plate 171', the central zone of this plate in which the tapped hole 171'A is formed advantageously has a thickness greater than that of its peripheral zone.

[0095] Such a configuration of the connection member 170' thus allows the use of different types of sleeves depending on the characteristics of the connection end pieces 331 provided at the ends of the flexible pipes 330.

[0096] Figures 11 and 12 illustrate another embodiment of the chassis according to the invention provided with connection members 180 welded to the side members 111.

[0097] Shown alone in [Fig. 13], each fluid connection member 180 comprises a plate 181 (in this case, of circular shape) having in its central part a circular bore 181A, as well as a sleeve 182, made of a single block with the plate 181, projecting from one of the faces of this plate from the periphery of this bore 181A and onto which is fitted, as illustrated in FIGS. 11 and 12, a connection end piece 331 formed at one end of a corresponding flexible pipe 330.

[0098] The plate 182 of each connecting member 180 is fixedly attached by welding against the internal lateral wall of the upper sealing portion PSE of a spar 111 on the periphery of a corresponding bore APSE.

[0099] Advantageously, this welding attachment is ensured by a weld bead produced by a friction stir welding process (commonly referred to by the English acronym FSW for "Friction Stir Welding") making it possible to assemble elements of significant thickness (up to 80 millimeters) while ensuring better preservation of the original mechanical resistance characteristics of the welded materials.

[0100] This weld bead furthermore preferably extends continuously over the entire peripheral periphery of the drilling 181A in order to also ensure sealing between this drilling and the corresponding bore APSE., which makes it possible to do without an annular groove such as 17 IB and a sealing joint such as 173.

[0101] Furthermore, and in order to avoid any risk of crushing the internal lateral wall of the upper sealing portion PSE of the spar 111 during the production of the weld bead and due to the considerable pressure force exerted by the welding pin against this wall, this upper sealing portion PSE may advantageously comprise, at the level of each of the upper cavities CPSEi and lower CPSE3, at least one horizontal flat reinforcing rib NHPSE extending between the two lateral walls of its outer envelope Epse so as to divide this cavity into several superimposed sub-cavities (see [Fig. 11]).

[0102] [Fig. 14] illustrates an alternative embodiment of a welded connection member 180' in which the sleeve 182' and the plate 181' are made up of two separate parts, the sleeve 182' being fixedly and tightly attached by screwing onto the bore 181'A of the plate 181' which is tapped.

[0103] In order to provide a sufficient screwing depth to ensure optimal fixing quality between the sleeve 182' and the plate 181', the central zone of this plate in which the tapped hole 181'A is formed advantageously has a thickness greater than its peripheral zone.

[0104] According to other variant embodiments of the invention not shown, the interior surface of each interior circulation pipe CPSE2 can be covered with a thermally insulating layer in order to limit heat losses.

[0105] Many other variants are also possible and it will be recalled in this respect that the invention is not limited to the embodiments described and shown, but also encompasses all the variants of execution within the reach of those skilled in the art.

Claims

Claims

1. Chassis (100) for a motor vehicle battery pack (1) comprising a rectangular frame (110) formed of two longitudinal side members (111) and two transverse cross members (112) fixed to each other at their ends, said side members (111) being constituted by extruded metal profiles each having at least one internal cavity (CPSE2) forming a circulation pipe for the liquid cooling circuit of the battery pack (1), each said side member (111) further having at least one transverse bore (APSE) produced after the extrusion process from one of its side walls and opening into said circulation pipe (CPSE2), each said bore (APSE) being in fluid communication with a corresponding connection member (170; 170'; 180; 180') fixedly attached to a said side member (111) and provided of a sleeve (172; 172'; 182;182') projecting from this spar (111) so as to allow a pipe (330) to be fluidly connected to it; characterized in that each said connecting member (170; 170'; 180; 180') also comprises a plate (171; 171'; 181; 181') having a bore (171A; 171'A; 181A; 181'A) in fluid communication with said sleeve (172; 172'; 182; 182'), said plate (171; 171'; 181; 181') being fixedly and tightly attached, by its face opposite said sleeve (172; 172'; 182; 182'), against a side wall of a said spar (111) on the periphery of a said bore (APSE).;

2. Chassis (100) according to claim 1, characterized in that said plate (171; 171') of each said connecting member (170; 170') is fixedly attached by screwing onto a said side wall of a said side member (111), by means of screws (V) passing through orifices (171C) provided in said plate (171; 171') and screwing into corresponding tapped holes (PT) provided in said side wall of a said side member (111).

3. Chassis (100) according to claim 2, characterized in that said screws (V) open inside two other internal cavities (CPSEi, C PSE3) formed in each said side member (111) respectively above and below said circulation pipe (CPSE2).

4. Chassis (100) according to one of claims 2 or 3, characterized in that said plate (171; 171') of each said connection member (170; 170') has, on its face opposite said sleeve (172; 172') and on the periphery of said drilling (171A; 171'A), an annular groove (171B) partially housing a sealing joint (173) coming into compression against said side wall of a said spar (111).

5. Chassis (100) according to claim 1, characterized in that said plate (181; 181') of each said connecting member (180; 180') is fixedly attached by welding to a said side wall of a said side member (111), by means of a weld bead.

6. Chassis (100) according to claim 5, characterized in that said weld bead extends continuously over the entire peripheral periphery of said drilling (181A; 181'A).

7. Chassis (100) according to one of claims 5 or 6, characterized in that said weld bead is produced by a friction stir welding process.

8. Chassis (100) according to one of claims 1 to 7, characterized in that said sleeve (172; 182) of each said connecting member (170; 180) is made of a single piece with said plate (171; 181) of this connecting member (170; 180).

9. Chassis (100) according to one of claims 1 to 7, characterized in that said sleeve (172'; 182') and said plate (171'; 181') of each said connecting member (170'; 180') are constituted by two separate parts, said sleeve (172'; 182') being fixedly and tightly attached by screwing onto said bore (171'A; 181'A) of said plate (171'; 181') which is tapped.

10. Chassis (100) according to claim 9, characterized in that the central zone of said plate (171'; 181') in which said tapped hole (171'A; 181'A) is formed has a thickness greater than that of its peripheral zone.

11. Chassis (100) according to one of claims 1 to 10, characterized in that a fluid connection end piece (150) is fixedly and tightly attached to a first end of said circulation pipe of each said side member (111), while a plug (160) is fixedly and tightly attached to the second end of said circulation pipe (CPSe2) of each said side member (111).

12. Chassis (100) according to one of claims 1 to 11, characterized in that the inner surface of each said circulation pipe (CPSe2) is covered with a thermally insulating layer.

13. Chassis (100) according to one of claims 1 to 12, characterized in that that said side members (111) and said cross members (112) are constituted by metal profiles of the same section (P) each comprising: - an upper sealing portion (PSE) extending vertically and in which said circulation pipe (CPSE2) is arranged, this upper sealing portion (PSE) having an upper face (F pse) intended to receive in a sealed manner the peripheral periphery of an upper cover (800) of said battery pack (1); and - a connection portion (PC) extending below said upper sealing portion (PSE) projecting laterally on either side of the latter, respectively from an external lateral overhang (DEPC) and an internal lateral overhang (DIPC) on which are respectively intended to be fixed attachment supports to the underbody of said vehicle and battery modules (200).

14. Chassis (100) according to claim 13, characterized in that each said profile also comprises a lower ground clearance portion (PGS) extending vertically below said connection portion (PC).

15. Battery pack (1) intended to be fixedly installed against the underbody of a motor vehicle, said battery pack (1) comprising a chassis (100), several battery modules (200) mounted on said chassis (100) and a cooling subassembly comprising a liquid cooling circuit in which a heat transfer fluid circulates as well as several exchanger devices (300) each provided with inlet nozzles (321) and outlet nozzles (322); characterized in that said chassis (100) is in accordance with one of claims 1 to 14, each said inlet nozzle (321), respectively outlet nozzle (322), being fluidically connected to said sleeve (172; 172'; 182; 182') of a respective said connecting member (170; 170'; 180; 180') fixed to a first, respectively second, said side member (111) by means of a corresponding connecting pipe (330).

16. A motor vehicle comprising a battery pack (1) according to claim 15.

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