ELECTRIFIED VEHICLE BATTERY PACK EQUIPPED WITH AN ANTI-FLAME FIXING DEVICE

Abstract

The battery pack (PB) is designed to be mounted under the body floor (CA) of an electrified vehicle and incorporates an anti-buckling fastening device (DAF). This device includes at least one omega-shaped reinforcement (OR) attached to a structural part of the pack and arranged so as to be able to be fixed to a mechanical interface (PM) of the vehicle's body floor, thus ensuring anti-buckling fastening. According to the invention, the structural part comprises a support structure (SP) arranged between two adjacent structural cross members (TSB1, TSB2) of the battery pack and fixed to them. The support structure includes a mechanical fastening support (PF1, PF2) for the omega-shaped reinforcement, and the mechanical fastening support is located on the support structure at a predetermined position between the two adjacent structural cross members. Figure 2

Description

Title of the invention: BATTERY PACK FOR ELECTRIFIED VEHICLES EQUIPPED WITH AN ANTI-FLAMING FIXING DEVICE

[0001] The present invention relates generally to the mechanical fastening of a traction battery pack under the floor of an electrified vehicle. More particularly, the invention relates to a traction battery pack for an electrified vehicle equipped with an anti-buckling fastening device designed to be assembled with a mechanical interface under the floor of the electrified vehicle.

[0002] In the prior art, the inventing entity is known to have a battery pack equipped with an anti-buckling fastening device of the prior art, the architecture of which is schematically represented in [Fig.1].

[0003] Generally, in the drawings of this patent application, an orthogonal XYZ coordinate system of the vehicle is used for the spatial orientation of the various components shown, with X, Y and Z being respectively the longitudinal, transverse and vertical axes of the vehicle.

[0004] In [Fig. 1], the aforementioned known architecture of the anti-buckling fastening device is shown in a simplified cross-sectional view in an XZ plane of the vehicle. The device comprises several sheet steel components forming the mechanical interface between the vehicle body CA and the traction battery pack BAT. These sheet steel components include, in particular, a shoring plate PM and, for each fastening point, an omega-shaped reinforcement RO, a bridge PO, and several fastening screws like those VI and V2 shown in [Fig. 1], as well as other parts not shown.

[0005] The PM mounting plate supports the mechanical attachment on the body side of the vehicle. This PM plate is positioned between two structural cross members of the body base, TS1 and TS2, and is fixed securely to them.

[0006] The RO omega reinforcement is a mechanical interface component between the CA casing and the BAT battery pack. In the BAT battery pack, the RO omega reinforcement is rigidly attached to a structural cross member TSB of the BAT battery pack via the aforementioned PO bridge. In this known architecture, the structural cross member TSB of the BAT battery pack to which the RO omega reinforcement is attached is aligned between the two aforementioned structural support cross members, TS1 and TS2, of the CA casing.

[0007] The structural crossmember TSB, as well as other similar crossmembers, are contained under a cover CP of the battery pack BAT and form the mechanical chassis of the battery pack BAT. This mechanical chassis supports the mechanical mounting of the cells electrochemical CE and electrical interconnection bars BB, known as "bus bars", of the battery pack BAT, as well as other components not shown.

[0008] Such an anti-buckling fastening device, thanks in particular to the RO omega reinforcement, performs several functions. During a vehicle homologation pole impact, the device prevents Z-shaped buckling of the vehicle's structural seat crossmembers. The device thus prevents the pole from intruding into the passenger compartment, an intrusion that could result in the seat tipping, with the driver being thrown towards the pole and an increase in the driver's chest deflections. The device allows for a degree of shear freedom in the XY plane to avoid strong coupling between the body (CA) and the battery pack (BAT), and prevents the generation of strong decelerations at the level of the electrochemical cells (CE) that could cause damage to the battery pack (BAT). Furthermore, the device is also beneficial in terms of controlling vibration behavior.

[0009] The anti-buckling fastening device architecture detailed above, with crossbeam alignment as described above, presents certain drawbacks. In this architecture, the structural base crossbeams TS1 and TS2 dictate the position of the RO omega reinforcement, which imposes a constraint on the position of the BAT battery pack structural crossbeam TSB. This constraint on the location of the RO omega reinforcement relative to the TSB, TS1, and TS2 crossbeams can prove detrimental if the BAT battery pack technology changes, requiring a modification of the X-shaped position of its structural crossbeams, typically to achieve better electrical autonomy by increasing the space dedicated to electrochemical cells or through more efficient thermal cooling.Furthermore, the continued use of the same platform for different vehicle models in the manufacturer's range requires a predetermined underbody position for the mechanical interface securing the battery pack (BAT), which leads to an alignment problem between this underbody mechanical interface and the structural crossmember of the battery pack if the latter's X-shaped position is changed.

[0010] In the prior art, US20240067002A1 discloses an anti-buckling method applicable to an electrified vehicle equipped with an underbody-mounted battery pack. This technology uses cables and shear plates to reduce the impact of buckling on the battery pack. Furthermore, US20200350533A1 discloses the presence of mechanically reinforcing ribs in the cover of a housing forming the outer casing of a traction battery pack for an electrified vehicle. DE102011077676A1 discloses the use of foam to fill cavities in an electric battery, between a wall of the battery housing and a set of electrodes.

[0011] The present invention aims to provide a solution to the aforementioned drawbacks of the anti-buckling fastening device of the prior art, as described above with reference to [Fig.1], in a battery pack of an electrified vehicle mounted under the floor of the vehicle body.

[0012] According to a first aspect, the invention relates to a battery pack for an electrified vehicle incorporating an anti-buckling fastening device for the battery pack under a vehicle body floor. The anti-buckling fastening device comprises at least one so-called "omega" type reinforcement fixed to a structural part of the battery pack and arranged so as to be able to be fixed to a mechanical interface of the body floor, thus ensuring anti-buckling fastening. In accordance with the invention, the structural part comprises a support structure arranged between two structural cross members adjacent to the battery pack and fixed to them. The support structure includes a mechanical fastening support for the so-called "omega" type reinforcement, and the mechanical fastening support is located on the support structure at a predetermined position between the two adjacent structural cross members.

[0013] According to a particular feature, the support structure is of the so-called "sandwich" type and is formed by a layering of several elements including a portion of an upper cover of a battery pack tray forming an upper skin of the support structure and a lower casing forming an lower skin of the support structure.

[0014] According to another particular feature, the support structure includes spacers arranged to maintain a required gap between the cover portion and the housing and, at the level of the spacers, a fixing by screws to bridges integral with the adjacent structural cross members, and the mechanical fixing support includes other bridges arranged between the cover portion and the housing which are intended for a mechanical fixing by screws of the reinforcement of the so-called "omega" type.

[0015] According to yet another particular characteristic, the housing is a part obtained by molding and the bridges intended for the mechanical fixing of the reinforcement of the so-called "omega" type are integrated from the material in the housing.

[0016] According to yet another particular characteristic, the housing is formed in a plastic material, and / or a resin, loaded with fibers.

[0017] According to yet another particular feature, the housing includes a network of ribs.

[0018] According to yet another particular feature, the other bridges intended for the mechanical fixing of the so-called "omega" type reinforcement include metal inserts providing threaded bores for screw fixing.

[0019] According to yet another particular feature, the support structure includes a filling material filling cavities present between the cover and the housing.

[0020] According to yet another particular feature, the support structure is housed in a space in the battery pack allocated to electrical interconnection bars thereof.

[0021] The invention also relates to an electrified vehicle comprising a battery pack mounted under a vehicle body floor, in which the battery pack is a battery pack with an anti-buckling fastening device as briefly described above.

[0022] Other advantages and features of the present invention will become more apparent upon reading the detailed description below of several particular embodiments of the invention, with reference to the accompanying drawings, in which:

[0023] Fig. 1 is a diagram showing in a simplified form an architecture according to the prior art of a battery pack equipped with an anti-buckling fastening device.

[0024] Fig. 2 is a schematic cross-sectional view showing the architecture of a battery pack according to the invention equipped with an anti-buckling fastening device.

[0025] Fig. 3 is another schematic cross-sectional view showing the architecture of Fig. 2 of a battery pack according to the invention.

[0026] Fig. 4 is a partial external perspective view of a battery pack according to the invention and its anti-buckling fastening device.

[0027] Fig. 5 is a cross-sectional view of the battery pack of Fig. 4 at the level of an omega reinforcement of its anti-buckling fixing device.

[0028] Fig. 6 is another cross-sectional view of the battery pack of Fig. 4 at the level of a fixing of a support structure of its anti-buckling fixing device on a structural cross member of the battery pack.

[0029] Fig. 7 is a partial perspective view of a rib network integrated into a lower housing of the anti-buckling fastening device of a battery pack according to the invention.

[0030] With reference to [Fig.2] and [Fig.3], the general architecture of a PB battery pack equipped with a DAF anti-buckling fastening device according to the invention is described below, shown by simplified cross-sectional views in the XZ and YZ planes of the vehicle.

[0031] As in the anti-buckling fastening device of the prior art described above with reference to [Fig.1], the DAF device of the invention includes in particular an omega reinforcement, here identified as OR, intended to be fixed to a PM shoring plate arranged under the body of the vehicle.

[0032] The PM shoring plate, similar to that described in relation to [Fig. 1], supports the mechanical anti-buckling fixing on the body side of the vehicle and is fixed to two structural cross members TS1 and TS2 of the body underbody.

[0033] Unlike the prior art, in the present invention, the omega-shaped reinforcement OR is not mechanically fixed directly to a structural cross member of the battery pack PB, which would constrain the X-shaped position of the reinforcement OR, but is fixed to a support structure SP arranged between two adjacent structural cross members, TSB1 and TSB2, of the battery pack PB. This feature of the invention provides a degree of freedom in the X-shape of the structural cross members TSB1 and TSB2 of the battery pack PB, and thus addresses the aforementioned drawbacks of the prior art.

[0034] In the PB battery pack, the support structure SP is of the so-called "sandwich" type and is formed by layering several elements. Thus, the support structure SP utilizes an upper cover PC of the PB battery pack tray, which forms the upper skin of the structure SP, a lower casing CI, which forms the lower skin of the structure SP, and an optional filling material MR, such as foam, which fills cavities between the cover PC and the casing CI. In the invention, integrating this support structure SP into the PB battery pack does not require an increase in the pack's Z-axis volume. Indeed, the invention provides for using a portion of the volume dedicated to the PB battery pack's electrical interconnection bars to house the support structure SP.

[0035] The lower housing CI is typically a molded part, made of plastic or resin, reinforced with fibers to enhance its mechanical properties and robustness. Depending on the embodiment, this housing CI may cover a significant portion of the underside of the upper cover PC, or even its entire surface, or it may only cover the upper cover locally, at the fastening interface, to form the support structure SP. Extending the housing CI beyond the area of ​​the support structure SP can be advantageous to fill a void in the battery pack PB with the filling material, thus reducing the amount of cooling fluid if the PB pack is cooled by immersion. As more clearly seen in [Fig. 3], the lower housing CI includes brackets PF1, PF2, typically molded from the material, for mechanically fastening the lugs of the omega reinforcement OR with screws. As seen in [Fig.2], EN1, EN2 spacers, with a smooth bore for screw passage, are also provided to maintain a required gap between the PC cover and the IC housing.

[0036] The support structure SP is fixed by screws to the two adjacent structural cross members TSB1 and TSB2 of the battery pack PB. The electrochemical cells CE occupy a delimited space between the cross members TSB1 and TSB2. Bridges OP1 and OP2, secured Mechanically attached to the structural cross members TSB1 and TSB2, these cross members are designed to raise them. Tapped holes are provided in the brackets OP1 and OP2 for screw attachment of the support structure SP. Screws V3 and V4, visible in [Fig. 2], contribute to this attachment of the support structure SP to the cross members TSB1 and TSB2. The cover PC, the housing CI, and the spacers EN1 and EN2, through which screws V3 and V4 pass, are secured to the cross members TSB1 and TSB2 by firmly tightening screws V3 and V4 in the tapped holes of the brackets OP1 and OP2.

[0037] As more clearly seen in [Fig. 3], the OR omega reinforcement is an added part, typically made of steel, with two mounting tabs. It is designed to be fixed by screws V5, V6, via its mounting tabs, to the PF1, PF2 brackets of the CI housing, clamping the PC cover through which the screws V5, V6 pass. Typically, the PF1, PF2 brackets each have a metal insert providing a threaded bore for the screws V5, V6. The OR omega reinforcement is mechanically fixed by a screw V7 to the PM mounting plate of the housing-side mounting interface.

[0038] A concrete embodiment PBC of a battery pack equipped with an anti-buckling fastening device DAF according to the invention is now described below.

[0039] As seen in [Fig. 4] showing a partial external view of the battery pack The PBC, DAF's anti-buckling fastening system, includes two omega-shaped reinforcements, ORD and ORG. These reinforcements provide anti-buckling support under the body, on the right and left sides of the seat, respectively. The four screw heads, marked VxD and VxG, which define a rectangle around the ORD and ORG omega reinforcements, are the heads of the screws that attach the respective support structures (SP) to the structural crossmembers of the PBC package, as described above.

[0040] With reference to [Fig. 5], the partial section AA shown here of the PBC battery pack and its underbody mounting is a section in a YZ plane at the level of the omega-shaped reinforcement ORD, as indicated in [Fig. 4]. The same reference marks used in [Fig. 2] and [Fig. 3] for certain components are used in this section AA.

[0041] In this [Fig. 5], on the side of the vehicle body, here labeled CAA, the PM mounting plate is visible. This plate supports the screw fastening of the omega-shaped reinforcement ORD to the CAA body, which is positioned opposite the omega-shaped reinforcement ORD. The space allocated for the electrical connection bars of the battery pack PBC, here labeled EBB, is used to house the SP support structure, as clearly shown in this [Fig. 5]. Metal inserts IT1 and IT2, embedded in the PF1 and PF2 brackets to provide threaded bores for the V5 and V6 fastening screws of the ORD reinforcement, are also visible in this [Fig. 5]. As also shown in [Fig. 5], O-ring seals JT1 and JT2 are provided to ensure the sealing of the PBC battery pack at the point where the ORD reinforcement tabs are attached to the PF1, PF2 bridges of the CI housing.

[0042] With reference to [Fig. 6], the partial section BB shown here of the PBC battery pack and its underbody mounting is a section in a YZ plane at the point where the SP support structure is attached to one of the structural cross members of the PBC pack, as shown in [Fig. 4]. The same reference numerals used in [Fig. 2], [Fig. 3], and [Fig. 5] are used in this section BB for certain components.

[0043] The CAA body of the vehicle, the PC cover and the CI housing of the SP support structure, as well as the EBB space dedicated to the electrical connection bars of the pack, are visible in [Fig.6].

[0044] The fixing screws, here labeled V3a and V3b, allow the mechanical fixing of the support structure SP onto the brackets, here labeled OP1a and OP1b, arranged above the structural cross member TSB1 of the PBC pack. The brackets OP1a and OP1b are typically steel parts attached to the cross member TSB1 and include threaded bores for the screws V3a and V3b. As also shown in [Fig. 6], O-ring seals JT3 and JT4 are provided to ensure the sealing of the PBC battery pack at the point where the support structure SP is fixed to the structural cross member TSB1 of the PBC pack.

[0045] In certain embodiments of the anti-buckling fastening device, the housing CI may include a network of ribs RN, as shown in [Fig. 7], to reinforce the mechanical strength of the support structure SP. Typically, the network of ribs RN will be arranged to form a rib mesh located around the openings in the housing CI intended for the passage of the fixing screws of the reinforcement ORD (ORG) and the fixing screws of the support structure SP to the structural cross members of the battery pack PBC. Such a network of ribs RN may be integrated on one or both faces of the housing CI, depending on the embodiment of the anti-buckling fastening device.

[0046] The invention addresses the need for battery pack technology changes when such changes require modifying the X-position of the battery pack cross members. This need to modify the X-position of the cross members may arise from choosing a different architecture, adding components to the battery pack, or changing its dimensions or those of its electrochemical cells. Battery pack technology changes are generally driven by the need for greater electric range for the vehicle, which requires more space for the electrochemical cells and consequently necessitates reducing constraints on the positioning of the battery pack cross members. The invention provides an economical and robust technical solution that meets this need while respecting the initial space allocated to the battery pack, weight constraints, as well as constraints related to the vehicle platform and the continuation of the body.

[0047] The invention is not limited to the particular embodiments described herein by way of example. A person skilled in the art may, depending on the applications of the invention, make various modifications and variations falling within the scope of the invention's protection.

Claims

Demands

1. Electrified vehicle battery pack (PB) incorporating an anti-buckling fastening device (DAF) of said battery pack (PB) under a body floor (CA) of said vehicle, said anti-buckling fastening device (DAF) comprising at least one omega-type reinforcement (OR) fixed to a structural part of said battery pack (PB) and arranged so as to be able to be fixed to a mechanical interface (PM) of said body floor (CA), thus ensuring said anti-buckling fastening, characterized in that said structural part comprises a support structure (SP) arranged between two adjacent structural cross members (TSB1, TSB2) of said battery pack (PB) and fixed thereto (TSB1, TSB2), said support structure (SP) comprising a mechanical fastening support (PF1, PF2) of said omega-type reinforcement (OR), and said mechanical fastening support (PF1,PF2) being located on said support structure (SP) at a predetermined location between the two said adjacent structural crossbeams (TSB1, TSB2).

2. Battery pack according to claim 1, characterized in that said support structure (SP) is of the so-called "sandwich" type and is formed by a layering of several elements comprising a portion of an upper cover (PC) of a tray of said battery pack (PB) forming an upper skin of said support structure (SP) and a lower casing (CI) forming an lower skin of said support structure (SP).

3. Battery pack according to claim 2, characterized in that said support structure (SP) comprises spacers (EN1, EN2) arranged to maintain a required spacing between said portion of cover (PC) and said housing (CI) and, at the level of said spacers (EN1, EN2), a fixing by screws (V3, V4) to bridges (OP1, OP2) integral with said neighboring structural cross members (TSB1, TSB2), and in that said mechanical fixing support comprises other bridges (PF1, PF2) arranged between said portion of cover (PC) and said housing (CI) which are intended for mechanical fixing by screws of said reinforcement of the so-called "omega" type (OR).

4. Battery pack according to claim 3, characterized in that said casing (CI) is a part obtained by molding and said other brackets (PF1, PF2) intended for the mechanical fixing of said reinforcement of the type said in “omega” (OR) are integrated from material in said casing (CI).

5. Battery pack according to any one of claims 2 to 4, characterized in that said housing (CI) is formed in a plastic material, and / or a resin, loaded with fibers.

6. Battery pack according to claim 5, characterized in that said housing (CI) comprises a rib network (RN).

7. Battery pack according to any one of claims 4 to 6 and claim 3, characterized in that said other bridges (PF1, PF2) intended for the mechanical fixing of said reinforcement of the so-called "omega" type (OR) comprise metal inserts (IT1, IT2) providing threaded bores for fixing by screws.

8. Battery pack according to any one of claims 2 to 7, characterized in that said support structure (SP) comprises a filling material (MR) filling cavities present between said cover (PC) and said housing (CI).

9. Battery pack according to any one of claims 1 to 8, characterized in that said support structure (SP) is housed in a space (EBB) of the battery pack allocated to electrical interconnection bars thereof.

10. Electrified vehicle comprising a battery pack mounted under a body floor (CA) of said vehicle, characterized in that said battery pack is a battery pack with an anti-buckling fastening device (PB) according to any one of claims 1 to 9.

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