Underbody protection system to protect a vehicle battery pack

Abstract

An underbody protection system designed to protect an electric vehicle battery pack (2) from potential impacts by objects from below the vehicle, the protection system comprising a first rail (41) and a second rail (42), the two rails being open towards each other, thus forming a guide along the longitudinal direction (X), characterized in that the protection system comprises a plurality of protective panels (5) arranged one after the other along the longitudinal direction (X), two adjacent panels being connected to each other by connecting means (7), each protective panel having a thickness (E5) along the vertical direction, a length (L5) generally corresponding to the width of the battery pack, and a width (W5) of between 15 cm and 60 cm, preferably between 20 cm and 50 cm. Figure 2

Description

Title of the invention: Underbody protection system for protecting a vehicle battery pack

[0001] The present invention relates to motor vehicles equipped with an electric drivetrain comprising a main battery pack located under the floor of the vehicle.

[0002] In such motor vehicles, it is necessary to provide a certain degree of protection to the battery pack against mechanical stresses which may come from under the vehicle, particularly when the vehicle is moving.

[0003] For example, the underside of the vehicle may receive projections of small pebbles or even small stones, which in this case have a high speed and therefore a significant kinetic energy.

[0004] Mechanical protection of the underside of the battery pack may also prove relevant in situations of life at zero or near zero speed, e.g. maneuvering on a parking bollard or object which gets stuck under the parked vehicle.

[0005] It is known from document EP4216351 that an integral protective plate is fitted under the vehicle's battery pack to meet the aforementioned requirements. If an impact occurs on the integral protective plate and it needs to be replaced, the necessary replacement part is of considerable size, making it difficult to store and handle.

[0006] Furthermore, the mandatory technical inspection of vehicles equipped with such a battery pack under the vehicle's structural floor will include a criterion for the proper functioning of the battery protection system. It would be useful to inform the user of any impact occurring under the vehicle, particularly to prepare the vehicle for the technical inspection and / or to ensure that it can continue to be used safely.

[0007] It is in this context that the inventors sought to propose a new solution for implementing the lower protection function of the battery pack. Additionally, it is desired that the proposed solution be able to provide information on the occurrence of damage, for example, as a result of impact with pebbles or stones.

[0008] To this end, an underbody protection system is proposed here, intended to protect an electric vehicle battery pack against possible impacts from objects from below the vehicle, the protection system and the vehicle being located in an orthogonal spatial frame comprising a vertical direction, a longitudinal direction and a transverse direction, the protection system comprising a first lateral rail and a second lateral rail, the two rails being spaced apart and open towards each other, the two rails thus forming a slide along the longitudinal direction or along the transverse direction, characterized in that the protection system comprises a plurality of protective panels, received in the slide, and arranged one after the other along the slide, two adjacent panels being connected to each other by connecting means.

[0009] It is noted that two opposite edges of each protective panel are received in the slide.

[0010] Thanks to the provisions set out above, by replacing the single plate with several panels, the protective panels have a form factor favorable to logistical operations including storage.

[0011] Moreover, advantageously, it is possible to replace only one damaged protective panel and keep the others, which reduces material consumption and the cost of repair.

[0012] Advantageously, the size of each protective panel is smaller than the size of the previous single plate that the panels replaced, making it easier to store and handle.

[0013] It should be noted that the impacting objects may be foreign bodies that arrive from underneath the vehicle.

[0014] According to one embodiment, a clearance space is provided between the protective panels and the underside of the battery pack. The clearance space has a free height E2 of a few millimeters, typically around ten millimeters.

[0015] According to an alternative embodiment, the protective panels 5 can be in contact with the underside of the battery pack, without a free gap.

[0016] Thus, a dent or a small dent in one or more protective panel(s), for example caused by a stone impact, does not have any adverse effect on the battery pack.

[0017] However, the extent of the panel deformation can be significant, and under the increasingly stringent criteria of regulatory technical inspections, it may be necessary to repair or even replace the damaged panel(s). We will see later that the invention optionally provides for the presence of impact sensor(s) in the protective panels to provide impact information, thus avoiding the need to place the vehicle on a lift to inspect its underside.

[0018] When the slide extends along the longitudinal direction X, the protective panels are arranged one after the other along the longitudinal direction.

[0019] According to one embodiment, each protective panel has a thickness along the vertical direction, a length generally corresponding to the width of the pack battery, and a width between 15 cm and 60 cm, preferably between 20 cm and 50 cm

[0020] In practice, each protective panel has two small dimensions and one large dimension (the length). This form factor is favorable to efficient storage in terms of space occupied.

[0021] When the slide extends along the longitudinal direction X, the length of each panel generally corresponds to the width of the battery pack, as the panels can slide along the longitudinal direction. However, it is possible for the slide to extend along the transverse direction Y, in which case the sliding direction of the panels in the slide would be perpendicular to the longitudinal direction of the vehicle.

[0022] According to one embodiment, the panel length is between 100 cm and 200 cm. According to a typical embodiment, the panel length will preferably be between 120 cm and 180 cm.

[0023] This is suitable for properly covering a battery pack that extends almost across the entire width of the vehicle. Moreover, it is also sufficient even if the width of the battery pack is substantially less than the width of the vehicle.

[0024] According to one embodiment, the joining means can be formed by tongue-and-groove edges. In other words, any form of tongue-and-groove joint that can form a joining means between the edges of two adjacent panels can be used within the scope of the present invention.

[0025] An assembly is thus formed by coupling generally complementary shapes.

[0026] According to one embodiment, the connecting means are formed by a female section on one of the longitudinal edges of the protective panel and by a male section on the other of the longitudinal edges of the protective panel. The male section is inserted into the female section.

[0027] Advantageously, such a solution is simple to implement and intuitive for garage maintenance operators who may need to disassemble and then reassemble the protection system. The respective male and female shapes are easily recognizable and form an intuitive assembly system.

[0028] According to an alternative solution, mutual fastening elements for the panels may be provided, for example, pine dowels, or even a strip with an H-shaped cross-section. In other words, complementary shapes on the long edges of the panels (tongue and groove or equivalent) are a preferred but not exclusive solution within the meaning of the present invention. Similarly, a tiling system between adjacent panels is not excluded.

[0029] According to one embodiment, at least one protective panel contains a sensor capable of detecting an impact of an intensity greater than a predetermined threshold.

[0030] Advantageously, information is made available to a user, whether the driver, maintenance personnel, owner, or fleet manager. This allows for planning an inspection for repair or for presentation to a mandatory technical inspection.

[0031] It should be noted that the shock sensor can be a capacitive sensor, a piezo-resistive sensor, or any other type of sensor capable of detecting either an acceleration or a deformation in the direction of the thickness of the panel.

[0032] According to one embodiment, each protective panel equipped with a sensor includes at least one means of electrical connection, with at least 2 ways.

[0033] According to a first possibility, at least one specific connector is provided on each panel directly linking two adjacent panels to form a general daisy-chain circuit.

[0034] According to a second possibility, the electrical connection means use the side rails, with a conductive element at the bottom of the groove that is contacted by a pad rubbing against the edge of the panel. The panels are then electrically powered in parallel. In this configuration, even if a protective panel suffers a serious break affecting, in particular, its electrical circuit, the neighboring panels continue to be electrically powered.

[0035] According to one embodiment, the shock sensor includes a circuit capable of transmitting messages by electromagnetic waves to a receiving unit; a local network system such as Wifi™ or Bluetooth™ can be used to support wireless communication.

[0036] According to another alternative solution, a third wired electrical path can be provided through which signals representing the information that the shock sensors make available are transmitted.

[0037] According to one embodiment, at least one of the two rails includes a movable lower support (e.g., a portion of the lower lip) to allow a downward passage in order to insert or remove a protective panel.

[0038] By opening the movable lower support, at least one panel can be removed from below, and then each of the other panels can be slid into this position to be removed in turn, one by one. This solution avoids having to leave a wide free passage at one longitudinal end, front or rear, of the protection system.

[0039] According to a first possibility, the movable lower support is pivotally mounted by means of a hinge.

[0040] According to a second possibility, the movable lower support is simply removable and re-mountable.

[0041] In practice, on the side of the lower movable support removed, one side of the protective panel is lowered and then the panel is released from the other rail so that it can be completely removed from the bottom.

[0042] It is noted that it is not excluded that each of the two rails includes a movable lower support, in which case the slide can be opened on both sides in Y and the panel can be extracted by rotating it only around the transverse direction Y.

[0043] According to one embodiment, the protective panels are made of composite material with a steel sheet and a polymer layer (e.g. polypropylene or polyethylene).

[0044] Preferably, the steel sheet is placed underneath and directed downwards, facing the road and potential impacts, while the polymer layer is directed in the opposite direction towards the battery pack. The polymer layer contributes to the desired structural rigidity aimed at limiting deflection and preventing vibrations and noise.

[0045] This composite solution represents a good compromise of mechanical performance, lightness, durability, fatigue resistance and moderate material cost.

[0046] According to one embodiment, the first and second side rails are fixed to one or more structural elements of the vehicle. The side rails can thus be removed without affecting the battery pack.

[0047] According to one embodiment, a first fixed stop is provided at a first longitudinal end of the slide to stop the longitudinal translation of a first protective panel, and a second stop, fixed or removable, is provided at the other longitudinal end of the slide, which allows the longitudinal translation of a last protective panel to be stopped when all the necessary panels are in place.

[0048] Wherefore, the plurality of protective panels are immobilized according to their translational movement in the longitudinal direction, by framing the longitudinal ends.

[0049] According to one embodiment, each protective panel is individually fixed to the side rails. The fixing can be achieved by means of self-drilling screws.

[0050] The present invention also relates to an assembly comprising a battery pack including a housing and a protection system as described above, in which the first lateral rail and the second lateral rail are fixed to the housing of the battery pack.

[0051] The present invention also relates to a motor vehicle, comprising a battery pack and a protection system as described above.

[0052] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig. 1] schematically represents in profile view an electric vehicle with a protection system according to the present invention; - [Fig.2] schematically represents the electric vehicle of [Fig.1] from below; - [Fig.3] schematically represents a cross-sectional view of the lower part of the electric vehicle of [Fig.1], illustrating the battery pack and the protection system which is placed underneath; - [Fig.4] schematically represents a longitudinal cross-sectional view of the battery pack and the protection system placed underneath; - [Fig.5] shows in perspective view an example of a protective panel; - [Fig. 6] illustrates a cross-section of an example of a connecting means that links two adjacent protective panels; - [Fig.7] illustrates in cross-section a protective panel equipped with a shock sensor and an electrical connection means; - [Fig.8] illustrates a stack of protective panels that can be found in the logistics circuit, particularly in storage; - [Fig.9] is analogous to [Fig.4] and shows a longitudinal cross-sectional view of a variant of the protection system placed under the battery pack; - [Fig. 10] schematically illustrates an example of means of connection electrically linking one panel to the next panel, with on the left (10A) the part containing the female electrical sockets and on the right (10B) the part containing the male electrical pins; - [Fig. 11] schematically illustrates another example of means of connection electrically linking one panel to the next panel, with on the left (1 IA) the part containing the electrical sockets and on the right (1 IB) the part containing the electrical pins; - [Fig. 12] schematically illustrates another example of connection methods where the protective panels are powered by a conductive element placed at the bottom of the rail groove; - [Fig. 13] schematically illustrates a variant of the protection system in which the guardrail is oriented in the transverse direction of the vehicle (instead of in the longitudinal direction as in the example shown in figures 2 to 4).

[0053] In the various figures, the same reference numerals designate identical or similar elements. For the sake of clarity, some elements are not necessarily shown to scale.

[0054] Fig. 1 shows an electric or hybrid vehicle (VH), equipped with an electric drivetrain including a main battery pack 2 located under the structural floor of the vehicle.

[0055] We speak of a main battery pack because it is not excluded that the vehicle includes another auxiliary battery located in another part of the vehicle.

[0056] It is noted that the invention covers all types of motor vehicles, the vehicles in question being able to be private vehicles, utility vehicles, vans, recreational vehicles.

[0057] The battery is housed in a battery casing which forms the structure of the battery pack. The lower wall 25 of the battery pack also acts as a cooling plate.

[0058] The invention proposes a protection system placed under the battery, the protection system being generally identified by the reference 1.

[0059] It is noted that there remains a classic ground clearance marked G, that is to say expressed in other words the presence of the protection system does not encroach on the ground clearance G of the vehicle.

[0060] In the figures, the vehicle and its battery are located with respect to an orthogonal frame of reference as follows: the vertical direction is noted Z, the horizontal direction called longitudinal is noted X, the horizontal direction called transverse is noted Y.

[0061] Figures show a battery pack 2 which occupies a significant part under the body of the vehicle in the quadrilateral between the four wheels 3. In practice, we are talking about an area of ​​at least 2 m2 or even at least 3 m2, without these values ​​being limiting.

[0062] In order to cover from below and protect such a battery pack surface, the protection system proposed here advantageously comprises a plurality of protective panels.

[0063] In the example shown in the figures, the main rectangular surface of the protection has a length L2 and a width L5. The main rectangular surface is covered by five protective panels 5. Of course, there could be more than five protective panels or fewer than five protective panels.

[0064] The length L2 of the battery pack is typically between 120 cm and 200 cm, without these values ​​being limiting.

[0065] The protective panels are arranged one after the other along the longitudinal direction X. In addition, two adjacent panels are connected to each other by connecting means which will be discussed later.

[0066] In the illustrated example, the signs are labeled P1, P2, P3, P4 and P5. It should be noted that for the present description, the first sign PI may be on the front side of the vehicle or may be on the rear side of the vehicle.

[0067] Each protective panel 5 has a thickness E5. The thickness E5 is typically between 1 mm and 20 mm depending on the material solution used. If the panel is made of sheet metal, its thickness can range from 1 mm to 2 mm. If the panel is made of a synthetic polymer (for example, polypropylene or polyethylene), its thickness can range from 5 mm to 12 mm.

[0068] According to a particularly relevant example, panel 5 is made of composite material with a steel sheet and a polymer layer, this composite

[0069] The steel sheet is placed underneath and oriented downwards, facing the road, while the polymer layer is oriented in the opposite direction towards the battery pack. The polymer layer contributes to the desired structural rigidity aimed at limiting deflection and preventing vibrations and noise.

[0070] The aforementioned thickness values ​​are not limiting.

[0071] The thickness E5 is in the range of 5 mm to 10 mm. The protective panel can The panel may have a constant thickness or, alternatively, may include reinforcing ribs that protrude from a protective panel. In its normal position under the vehicle, the thickness E5 extends along the vertical Z direction of the vehicle.

[0072] The protective panel has a length L5 generally corresponding to the width W2 of the battery pack, which extends along the transverse direction Y when the protective panel is in its normal position under the vehicle.

[0073] The protective panel 5 has a width W5 which extends along the longitudinal direction X when the protective panel is in its normal position under the vehicle.

[0074] Cleverly, the width W5 is between 20 cm and 50 cm, which allows for a form factor that facilitates compact storage of several panels stacked on top of each other, as shown in [Fig. 8]. It should be noted that a panel can also be stored upright with a footprint E5 x W5 well below its length L5 or the length of a protective plate that would be a single, integral piece under the entire battery pack, as in known practice.

[0075] As schematically illustrated in [Fig.8], the set of protective panels 50 used to form a protection system can be stacked on top of each other while occupying a limited storage volume.

[0076] The length L5 is between 100 cm and 200 cm, preferably between 120 cm and 180 cm, consistent with W2.

[0077] The protective panel 5 comprises two large faces 52, 56, two longitudinal edges 53, 54, and two small edges 51.

[0078] The gap E2 left free between the top of the protective panels 5 and the bottom of the battery pack can be between 5 mm and 15 mm.

[0079] According to an alternative embodiment, the gap E2 can be zero, i.e. the protective panels 5 are then in contact with the underside of the battery pack.

[0080] As seen in [Fig.2] and 3, the protective panels are held in place by means of two lateral rails, a left lateral rail and a right lateral rail.

[0081] The left side rail forms a first rail 41 and a right side rail forms a second rail 42. The two rails are spaced apart from each other generally by a distance W2 which is generally close to the length L5 of the protective panels.

[0082] The two rails are open towards each other. Each rail is formed as an extruded profile that extends parallel to X. The rails can be manufactured by extruding aluminum material.

[0083] The profile section has a U-shaped groove with a bottom and an opening directed along Y. The two rails thus form a slide 4 in the longitudinal direction. The slide receives the protective panels 5, which can slide along the longitudinal axis X. The slide receives two opposite edges of the protective panels 5. More precisely, each of the two small slices 51 of a panel is received respectively in the first rail 41 and in the second rail 42.

[0084] The distance separating the two bottoms of the groove is slightly greater than L5 and corresponds to the length L5 plus a small functional clearance (a few mm).

[0085] A lower support or lip 44 and an upper support or lip 45 are provided which together frame the end edges 51 of the length of the protective panels 5. The lower lip 44 and the upper lip 45 can frame the panel edges, respectively from below and above, with minimal clearance that facilitates the sliding of the panels. Local surface features, for example, raised bumps, can be provided to eliminate this clearance and prevent any rattling that could potentially cause noise.

[0086] The two rails can be attached to a component of the vehicle body as illustrated in [Fig.3]. The rails can then be removed without affecting the battery pack.

[0087] Alternatively, the two rails can be fixed to the battery housing. The whole assembly can then be disassembled as a unit

[0088] As shown in [Fig. 4], a fixed stop 61 is provided at one longitudinal end of the slide to stop the longitudinal translation of a first protective panel PI, and a fixed stop 61 is provided at the other longitudinal end of the slide. slide, a removable stop system 62 which allows to stop the longitudinal translation of a last protective panel P5.

[0089] In this configuration, the panels are introduced along the longitudinal direction X from the end where the removable stop is located.

[0090] As seen in [Fig.9], at the location of a longitudinal end of a rail, a part of the lower support of the rail, denoted 67, is movable either by rotation thanks to a hinge 66 or purely removable.

[0091] In the configuration of [Fig. 9], the two outermost stops 61, 63 in the longitudinal direction can be fixed stops, with access to the protective panel from below. Access to the protective panel 5 from below can be located on the front or rear side of the vehicle.

[0092] These stops can be a complete wall or discrete stop elements.

[0093] In this case, the protective panel which is located at this point can be lowered on the side where the rail is no longer complete, and the protective panel can be released from the rail on the other side.

[0094] Of course, means of connection 68 are provided to maintain the movable element in its normal position for use of the vehicle, for example of the type of screw, peg, pin or any other means of connection or retention.

[0095] One of the stops may include an elastic means for creating a residual stress in the direction of the slide (X here) to press the edges of the panels against each other and thus prevent any relative movement.

[0096] Means of connection

[0097] In the example illustrated in figures 4 and 5, the connecting means 7 are formed on one side by a convex shape with a vertex 55, and on the opposite side by a complementary concave shape with a groove bottom 57 in which the corner 55 of the opposite panel is housed.

[0098] Generally expressed, the panels 5 fit into each other by the long edges.

[0099] In the example illustrated in figures 5, 10 and 11, the connecting means 7 are formed on the one hand by a female section 71 on one of the longitudinal edges 5B of a protective panel and on the other hand on the longitudinal edge 5A opposite another protective panel by a male section 72.

[0100] Two ribs 73 of the female section frame a rib 74 of the male section; this interface allows for the transmission of forces, which contributes to the overall rigidity. Chamfers may be provided at the entry points to facilitate docking and coupling.

[0101] The free front end of the male rib via contact with the bottom of groove 75 interposed between the ribs 73 of the female section.

[0102] Generally speaking, the joining means can be formed by tongue-and-groove edges. In other words, any form of tongue-and-groove joint that can form a joining means between two adjacent panels 5 can be used within the scope of the present invention.

[0103] Sensor and connectivity

[0104] According to an advantageous option, at least one protective panel contains a shock sensor 8 capable of detecting a shock of an intensity greater than a predetermined threshold or capable of detecting a rate of deformation greater than a predetermined threshold.

[0105] According to another advantageous option, all the protective panels individually contain a shock sensor capable of detecting a shock of an intensity greater than a predetermined threshold.

[0106] It is envisaged that the shock sensors will be able to provide information that is made available to a user. This user may be the vehicle driver, garage maintenance personnel, the owner, or the fleet manager. This allows for the planning or scheduling of an inspection of the underside of the vehicle for repair or presentation for a mandatory technical inspection.

[0107] According to an advantageous provision, in the case where each of the panels individually contains a shock sensor it is possible to determine which panel has been damaged by a shock and therefore to propose the replacement of that particular panel while retaining the other panels.

[0108] Regarding the sensor technology, the shock sensor can be a capacitive sensor, a piezoresistive sensor, or any other type of sensor capable of detecting either an acceleration or a deformation in the direction of the thickness of the panel.

[0109] The shock sensor 8 is presented as a sensing ribbon. The ribbon can be located rather towards the lower face of the panel 56, or in the thickness at mid-height, or rather towards the upper face 52 of the panel, or the ribbon can be formed as the outer upper layer of the panel.

[0110] Each protective panel equipped with a sensor includes at least one means of electrical connection, with at least two ways 81,82,84.

[0111] According to a first possibility, a specific connector is provided on each panel directly linking two adjacent panels. In the example illustrated in Figures 10 and 11, each panel includes on one side two female sockets 33, 34 and on the other side, in corresponding transverse position, two male pins 35, 36. When two adjacent panels are joined by the mechanical means, the two electrical paths are also established by the coupling of the pins in the sockets (axes A3 on A5 and axis A4 on A6).

[0112] The system thus comprises a general daisy-chain circuit with the panels in series mode. A power supply unit is provided, configured to deliver a power supply to the panels at a voltage that can be 12 volts, or even regulated to 5 volts, without excluding other possibilities.

[0113] It is noted that in [Fig. 10] the pins are located inside the female groove of the mechanical linkage means, which provides adequate protection for the pins, which are thus not protruding.

[0114] The solution illustrated in [Fig. 11] consists of using an electrical equipment strip 38 arranged on the edge of the base protection panel, and it is the electrical equipment strip 38 which has the sockets on one side and the pins on the opposite side.

[0115] According to a second possibility, the electrical connection means use the side rails, with a conductive element at the bottom of the groove that is contacted by a pad rubbing against the edge of the panel. The panels are then electrically powered in parallel. In practice, as illustrated in [Fig. 12], a first partially sheathed conductive element 31 is located at the bottom of the groove of the first rail 41 and a second partially sheathed conductive element 32 is located at the bottom of the groove in the second rail 42.

[0116] In this configuration, even if a protective panel suffers a serious break affecting in particular its electrical circuit, the neighboring panels continue to be electrically supplied.

[0117] The slide rails are electrically connected to the vehicle's ground. Therefore, contact with a rail can be used to supply negative power to the panels. The two dedicated electrical channels are then used respectively for positive power and the data signal channel (LIN type serial bus or other).

[0118] According to one embodiment, the shock sensor includes a circuit capable of transmitting messages by electromagnetic waves to a receiving unit (not visible in the figures); a local network system such as Wifi™ or Bluetooth™ can be used to support wireless communication between the shock sensors and the receiving unit.

[0119] The receiving unit can be combined with the power supply box delivering voltage to the panels.

[0120] Y-shaped variant

[0121] In this variant, the guardrail 4 is oriented in the transverse direction of the vehicle Y. The length of the protective panels L5 can be quite substantial if the battery is covered in a single span. This length can be close to 200 cm or even more.

[0122] It is not excluded to have two slides side-by-side, one in front and the other behind, each oriented along Y in order to cover a significant distance in X.

[0123] In this variant, the linking means and the shock-absorbing function may be identical or similar to what has been described previously.

[0124] According to a particular advantage, related to removal and reassembly, it may be possible, in order to remove the protective panels, to slide them out of the rail linearly horizontally on the side of the vehicle, after removing the movable stop; the rail is then simplified.

[0125] The use of a lower support for the movable rail remains possible, however.

Claims

Demands

1. Underbody protection system, intended to protect a battery pack (2) of an electric vehicle against possible impacts from objects from below the vehicle, the protection system and the vehicle being located in an orthogonal spatial frame comprising a vertical direction (Z), a longitudinal direction (X) and a transverse direction (Y), the protection system comprising a first rail (41) and a second rail (42), the two rails being spaced apart and open towards each other, the two rails thus forming a slide along the longitudinal direction (X) or along the transverse direction (Y), characterized in that the protection system comprises a plurality of protection panels (5), received in the slide, and arranged one after the other along the slide, two adjacent panels being connected to each other by connecting means (7).

2. A protection system according to claim 1, wherein each protective panel has a thickness (E5) along the vertical direction, a length (L5) generally corresponding to the width of the battery pack, and a width (W5) between 15 cm and 60 cm, preferably between 20 cm and 50 cm.

3. Protection system according to claim 2, wherein the length (L5) is between 100 cm and 200 cm, preferably between 120 cm and 180 cm.

4. A protection system according to any one of claims 1 to 3, wherein the connecting means (7) are formed by a female section on one of the longitudinal slices of the protection panel and by a male section on the other of the longitudinal slices of the protection panel.

5. A protection system according to any one of claims 1 to 4, wherein at least one protective panel contains a sensor (8) capable of detecting an impact of an intensity greater than a predetermined threshold.

6. A protection system according to claim 5, wherein each protective panel equipped with a sensor comprises at least one means of electrical connection, with at least 2 ways.

7. A protection system according to any one of claims 1 to 6, wherein at least one of the two rails comprises a support lower (44) movable to leave a passage downwards in order to insert or remove a protective panel.

8. A protection system according to any one of claims 1 to 7, wherein the protective panels (5) are made of composite material with a steel sheet and a polymer layer.

9. A protection system according to any one of claims 1 to 8, wherein a first stop (61) is provided at a first longitudinal end of the slide to stop the longitudinal translation of a first protective panel (PI), and a second stop (62) is provided at the other longitudinal end of the slide to stop the longitudinal translation of a last protective panel (P5).

10. Vehicle (VH) comprising a battery pack (2) and an underbody protection system (1) according to any one of claims 1 to 9.

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