Protective device for a vehicle trunk battery pack.

Abstract

The invention relates to a battery pack protection device (1) designed to be mounted in the trunk structure of a motor vehicle, the device (1) being designed to extend between a rear trunk panel of the vehicle and a rear support crossmember of the vehicle, the device (1) comprising energy-absorbing means (11) shaped to absorb, by deforming, when the device (1) is mounted in the vehicle's trunk, a portion of the energy of a rear impact transmitted to the rear panel, the device (1) having a floor surface (10) shaped to form at least a portion of a trunk floor of the vehicle between the rear panel and the support crossmember. The invention also relates to a trunk structure comprising such a device (1) and a vehicle equipped with such a trunk structure. (Figure 3)

Description

Title of the invention: Device for protecting a battery pack in the trunk of a motor vehicle.

[0001] The technical field relates to devices for protecting battery blocks of motor vehicles, trunk structures equipped with such protective devices and motor vehicles having such a structure.

[0002] Electric vehicles are experiencing growing interest from customers, while their ranges are constantly being improved by car manufacturers. To achieve this, the industrial players involved have invested heavily in the development of new technologies to offer ever more efficient batteries, i.e. batteries offering increased charging speeds, constantly increasing capacities and high energy densities.

[0003] Alongside the improvement of technologies, car manufacturers are also focusing on increasing the volume dedicated to batteries in their electric vehicles. However, current batteries suffer from disadvantages inherent to the technologies used, particularly their instability in the event of an impact: a battery cell damaged following an impact can in fact run away and cause a fire.

[0004] Also, due to fire risks, certain areas of a vehicle are considered exclusion zones where battery installation is prohibited because of the high probability of deformation in the event of an impact. Thus, the area near the rear panel is considered an exclusion zone because of the deformation phenomenon that causes the rear panel to penetrate the vehicle's trunk in the event of a rear-end collision. This penetration of the rear panel causes deformation of the trunk floor and surrounding components. A battery located in this area would therefore be at risk of being violently impacted by the rear panel and being dangerously damaged. A rear-end collision is defined as a simulated impact on the vehicle using a dolly that strikes the vehicle from the rear under standardized speed and direction conditions, which are part of the type-approval requirements.

[0005] Car manufacturers are seeking to reduce exclusion zones. Thus, there is a need for a solution to allow the use of the space located near the rear panel of a vehicle.

[0006] The present invention aims to overcome the problems described above.

[0007] To this end, the present invention relates to a block protection device batteries designed to be mounted in a trunk structure of a motor vehicle, the device being designed to extend between a rear trunk panel of the vehicle and a rear support crossmember of the vehicle, the device comprising energy absorption means shaped to absorb by deforming, when the device is mounted in the trunk of the vehicle, part of the energy of a rear impact transmitted to the rear panel, the device having a floor surface shaped to form at least part of a floor of the trunk of the vehicle between the rear panel and the support crossmember.

[0008] The invention also relates to a motor vehicle trunk structure, comprising a support crossmember and a rear panel, the structure further comprising a protection device according to the invention arranged between the support crossmember and the panel, the device forming at least part of the trunk floor between the support crossmember and the panel.

[0009] The invention finally relates to a motor vehicle comprising a trunk structure according to the invention.

[0010] Thus, a battery pack protection device according to the invention makes it possible to equip a motor vehicle according to the invention, which therefore has a trunk structure according to the invention. The device is capable of absorbing all or part of the energy released during a rear-end collision on the vehicle that deforms the rear panel. As the rear panel moves backward in the vehicle's trunk, it impacts the protection device according to the invention. Consequently, the absorption means of the device, by deforming in a programmed manner, absorb all or part of the energy released by the rear-end collision, so that the forward movement of the rear panel in the trunk is limited. With the device according to the invention, the trunk structure according to the invention is therefore capable of withstanding a greater rear-end collision than a conventional vehicle trunk that does not have a protection device according to the invention.With equal impact energy released, the projection of the rear panel into the trunk is therefore less with a trunk structure according to the invention. Thus, a battery pack can be placed at a shorter distance from the rear panel compared to a conventional vehicle trunk. The protection device according to the invention therefore makes it possible to reduce exclusion zones.

[0011] According to one embodiment of the invention, the device comprises a plate extending between a first and a second face, the plate being designed to extend at least between the rear panel and the support crosspiece, the first face of the plate presenting the floor surface, the second face being provided with energy absorption means.

[0012] According to one possibility, the plate is shaped to come to bear on the support crosspiece.

[0013] According to one embodiment, the device is made of composite material of fiber-reinforced plastic.

[0014] According to one possibility of the invention, the absorption means comprise a plurality of longitudinal reinforcements projecting from the second face of the plate, each longitudinal reinforcement extending along a longitudinal axis of the vehicle, when the device is mounted in the trunk of the vehicle.

[0015] Advantageously, the absorption means comprise a plurality of absorbent foam blocks each arranged between two successive longitudinal reinforcements.

[0016] According to one embodiment, the structure further comprises a battery pack arranged under the trunk floor and fixed to the support cross member, the support cross member being arranged between the battery pack and the protection device.

[0017] The invention will be better understood on reading the detailed description which follows, given solely by way of non-limiting example and made with reference to the appended drawings in which:

[0018] [Fig-1] [Fig.1] represents a partial perspective and bottom view of a chest structure according to the invention comprising a first embodiment of a protection device according to the invention;

[0019] [Fig.2] [Fig.2] represents a partial perspective and top view of the trunk structure according to the invention equipped with a battery pack;

[0020] [Fig.3] [Fig.3] represents a perspective view, from below, of a second embodiment of a protection device according to the invention.

[0021] In these figures, the same references are used to designate the same elements.

[0022] A device 1 according to the invention, illustrated in Figures 1 to 3, is designed to be mounted in a trunk structure 2 according to the invention, partially illustrated in Figures 1 and 2. The protection device 1 is designed to protect, in the event of a rear impact, a battery pack 3 also mounted in the trunk structure 2. The battery pack 3 comprises one or more batteries arranged in a rigid enclosure 4, visible in [Fig.2].

[0023] The trunk structure 2 comprises a support crossmember 5 and a rear panel 6 on which a trunk opening, not shown, is fixed. The support crossmember 5 extends across the structure 2 and allows the battery pack 3 to be fixed to the crossmember 5. The crossmember 5 is arranged at a distance from the rear panel 6, between the battery pack 3 and the rear panel 6.

[0024] The protection device 1 according to the invention is arranged between the support crosspiece 5 and the panel 6.

[0025] The trunk structure 2 conventionally comprises a sheet metal 7 forming part of a trunk floor 8 of the structure 2, visible in [Fig. 2]. The battery pack 3 is arranged under the sheet metal 7, as illustrated in [Fig. 2]. The sheet metal 7 partly matches the shape of enclosure 4 and thus forms an elevation 9 of floor 8.

[0026] As illustrated in Figures 1 and 2, the device 1 is designed to extend between the rear trunk panel 6 and the rear support cross member 5. In this case, the protection device 1 is placed in the volume delimited between the raised portion 9 and the rear panel 6. The device 1 has a floor surface 10 shaped to form at least part of the floor 8 of the trunk of the vehicle, between the rear panel 6 and the support cross member 5. The floor 8 is therefore formed from the floor surface 10 and the raised portion 9. The floor surface 10 constitutes an extension of the raised portion 9 so that the floor 8 is generally flat.

[0027] The device 1 further comprises energy absorption means 11 shaped to absorb by deforming, when the device 1 is mounted in the trunk structure 2 of the vehicle, part of the energy of a rear impact transmitted to the rear panel 6.

[0028] The protective device 1 is, for example, made of a composite material of the BMC or SMC type. BMC materials are materials comprising an unsaturated, thermosetting polyester base, with an added anti-shrinkage agent, mineral reinforcing agents and fibers. SMC materials are formed from a relatively homogeneous mixture of resin and reinforcing fibers, cut or not, with or without filler, in the form of a sheet with a thickness generally between 1 and 25 mm. Alternatively, the device 1 is made at least partly of polypropylene. The protective device 1 is, for example, obtained by injection or molding.

[0029] As illustrated in the figures, the device 1 comprises a plate 12 extending between a first 13 and a second 14 faces. The plate 12 is shaped to extend at least between the rear panel 6 and the support crosspiece 5. The first face 13 of the plate 12 has the floor surface 10, the second face 14 being provided with the energy absorption means 11.

[0030] The plate 12 has a body 15 of generally parallelepiped shape, the first face 13 extending beyond the body 15 to form a rim 16, illustrated in FIGS. 1 and 3. In particular thanks to the rim 16, the plate 12 is shaped to come to bear on the support crosspiece 5.

[0031] As illustrated in Figures 2 and 3, the absorption means 11 comprise a plurality of longitudinal reinforcements 17 projecting from the second face 14. For example, as illustrated in the figures, each reinforcement 17 comprises a wall 18 which extends along a longitudinal axis of the vehicle, when the device 1 is mounted in the trunk structure 2.

[0032] Each reinforcement 17 is shaped to have a programmed deformation capable of absorbing part of the energy of a rear impact. Thus, in the embodiment illustrated in the figures, in the event of a rear impact, the device 1 undergoes compression along the longitudinal axis of the vehicle causing the programmed deformation of the reinforcements 17.

[0033] The walls 18 of the reinforcements 17 each have a V or U shape projecting from the second face 14 of the plate 12, the tip of the V or U being located at a distance from the plate 12.

[0034] By way of non-limiting example, each reinforcement 17 has a height measured from the second face 14 of the order of 60 mm, for a width of 35 mm. The body 15, for its part, has a thickness of the order of 30 mm. In the example illustrated in the figures, the device 1 comprises three reinforcements 17 spaced approximately 135 mm apart. Alternatively, the device 1 has a variable number of reinforcements 17, for example between 3 and 6 or more, the reinforcements 17 then being more or less close to each other.

[0035] In order to improve the energy absorption capacity of the device 1, the absorption means 11 comprise, in a second embodiment illustrated in [Fig. 3], a plurality of blocks 19 of absorbent foam each arranged between two successive longitudinal reinforcements 17.

[0036] Thus, the device 1 according to the invention makes it possible to occupy a generally unoccupied space between the raised portion 9 and the panel 6 and makes it possible to absorb all or part of the energy of a rear impact in order to limit the forward movement of the panel 6 into the trunk. The exclusion zone is thus reduced and the battery pack 3 can occupy a larger volume.

[0037] The invention is not limited to the embodiments of the protection devices or the trunk structure described above, only by way of example, but other embodiments can be designed by those skilled in the art without departing from the framework and scope of the present invention.

Claims

Claims

1. Device (1) for protecting a battery pack (3) designed to be mounted in a trunk structure (2) of a motor vehicle, the device (1) being designed to extend between a rear trunk panel (6) of the vehicle and a rear support crossmember (5) of the vehicle, the device (1) comprising energy absorption means (11) shaped to absorb by deforming, when the device (1) is mounted in the trunk of the vehicle, part of the energy of a rear impact transmitted to the rear panel (6), the device (1) having a floor surface (10) shaped to form at least part of a floor (8) of the trunk of the vehicle between the rear panel (6) and the support crossmember (5).

2. Device (1) according to claim 1, characterized in that it comprises a plate (12) extending between a first (13) and a second (14) face, the plate (12) being designed to extend at least between the rear panel (6) and the support crosspiece (5), the first face (13) of the plate (12) having the floor surface (10), the second face (14) being provided with the energy absorption means (11).

3. Device (1) according to claim 2, characterized in that the absorption means (11) comprise a plurality of longitudinal reinforcements (17) projecting from the second face (14) of the plate (12), each longitudinal reinforcement (17) extending along a longitudinal axis (A) of the vehicle, when the device (1) is mounted in the trunk of the vehicle.

4. Device (1) according to one of claims 1 to 3, characterized in that the device (1) is made of fiber-reinforced plastic composite material.

5. Device (1) according to one of claims 1 to 4, characterized in that the absorption means (11) comprise a plurality of blocks (19) of absorbent foam each arranged between two successive longitudinal reinforcements (17).

6. Structure (2) of a motor vehicle trunk, comprising a support cross member (5) and a rear panel (6), the structure (2) further comprising a protection device (1) according to one of claims 1 to 5 arranged between the support cross member (5) and the panel (6), the device (1) forming at least part of the trunk floor (8) between the support cross member (5) and the panel (6).

7. Trunk structure (2) according to claim 6, characterized in that it further comprises a battery pack (3) arranged under the trunk floor (8) and fixed to the support cross member (5), the support cross member (5) being arranged between the battery pack (3) and the protection device (1).

8. Motor vehicle comprising a trunk structure (2) according to claim 6 or 7.

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