VEHICLE TRACTION BATTERY SYSTEM WITH ENTRY INTO THE FIRE EXTINGUISHING FLUID TANK

Abstract

A traction battery system for an electric or hybrid motor vehicle, comprising a battery (2) disposed in a closed casing (4) having an external inlet (6) for supplying fire extinguishing fluid, characterized in that it includes a means for detecting (12) a fluid level threshold in the battery casing (4), and an automatic device for opening this casing (4) to the outside as a function of the detection of this threshold. Figure 1.

Description

Title of the invention: VEHICLE TRACTION BATTERY SYSTEM WITH FIRE EXTINGUISHING FLUID INTAKE IN THE TANK

[0001] The present invention relates to an electric or hybrid motor vehicle traction battery system comprising a fire extinguishing fluid inlet in a battery compartment, as well as an electric or hybrid vehicle equipped with such a battery system.

[0002] Vehicle traction batteries, most of which are equipped with lithium-ion cells to achieve high energy density, generally include a cooling system to maintain them within an optimum temperature range, ensuring good performance and safety. However, in the event of cell failure, a failure of the cooling system or the battery control device, or an external accident, cell damage can occur, causing a sharp rise in their temperature and the emission of hot gases that are toxic and flammable. In such cases, a significant supply of cooling and extinguishing fluid, generally water, is required to combat overheating and fire, in order to cool the cells and prevent accidents.

[0003] To this end, a known type of electric or hybrid vehicle, described in particular by document FR-A1-3002910, comprises a rear load-bearing structure located under the trunk, including longitudinal members and cross members forming hollow sections enclosing a battery that powers an electric traction motor for this vehicle. An easily accessible opening at the rear of the vehicle provides access to the hollow sections of the structure, which form a conduit leading to the battery compartment. This compartment can receive the extinguishing fluid delivered by firefighters to fill the battery compartment.

[0004] However, after the battery compartment, which is sealed to ensure its protection, has been filled, it is no longer possible to add any additional cooling fluid. A defined volume of fluid remains in the compartment, and without the addition of new fluid, this defined volume can, depending on the amount of heat released by the failing cells, cause problems of uncontrolled temperature rise, with risks of continued degradation and accidents.

[0005] The present invention is intended in particular to avoid these problems of the prior art.

[0006] To this end, it proposes a traction battery system for an electric or hybrid motor vehicle, comprising a battery disposed in a closed casing having an external inlet for supplying fire extinguishing fluid, this the system being remarkable in that it includes a means of detecting a fluid level threshold in the battery box, and an automatic device for opening this box to the outside according to the detection of this threshold.

[0007] An advantage of this battery system is that in the event of a cell failure causing the battery to overheat, if the casing is filled with a cooling fluid and a high level of this fluid is detected in the casing exceeding the threshold, the automatic device opens the casing to the outside to allow the hot fluid to flow out.

[0008] This allows the casing to continue to be supplied with a cold external fluid which maintains cooling of the battery.

[0009] The battery system according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0010] Advantageously, the automatic opening device of the box, when activated, connects this box with an external volume to transfer this fluid to it.

[0011] In this case, advantageously the box opening device includes a hollow rod which slides in a wall of this box after detection of the fluid level threshold, in order to enter the external volume.

[0012] Moreover, advantageously the hollowed rod has a front tip coming out of the box which, when it slides, enters the outer volume by passing through a shutter closing this volume.

[0013] Advantageously, the hollowed rod has a front hole which after sliding entered the outer volume to pour the fluid into it.

[0014] Advantageously, the battery system includes a worm gear driven by a motor which makes the hollow rod slide.

[0015] Advantageously, the detection means includes a level sensor disposed in the upper part of the box.

[0016] Advantageously, the box includes a battery volume comprising the battery and the fluid inlet, and a filling volume separated by a movable partition which moves to enlarge this battery volume when the automatic opening device of the box is actuation, allowing fluid to be poured over this partition into the filling volume.

[0017] The invention also relates to an electric or hybrid motor vehicle equipped with a traction battery for this vehicle, remarkable in that this battery contained in a casing is part of a battery system comprising any one of the preceding characteristics.

[0018] Advantageously, the vehicle includes a side member of the vehicle body forming an external volume receiving the fluid after the automatic opening device of the box has been activated.

[0019] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0020] [Fig. 1] is a diagram showing in vertical section a battery system according to the invention arranged in a vehicle, comprising an initial filling of the casing with a low level of extinguishing fluid which is below the level threshold; and

[0021] [Fig.2] is a diagram showing this battery system with a significant level of extinguishing fluid having exceeded this level threshold.

[0022] Throughout the document the upper or top direction is relative to the vertical axis of a vehicle that is placed on a horizontal ground.

[0023] Fig. 1 presents a traction battery 2 of an electric or hybrid motor vehicle, contained in a closed box 4 equipped in the upper part with a supply conduit 6 for extinguishing fluid forming an inlet accessible from outside the vehicle, to allow the firefighters to fill this box in case of excessive heating or fire inside.

[0024] The casing 4 has on the side of the battery 2 an internal partition 8 separating a first volume surrounding this battery 16, comprising in the upper part the supply conduit 6 to fill this first volume, from a second filling volume 10 beyond this partition.

[0025] The internal partition 8 has in its upper part a maximum threshold sensor for the fluid level 12 in the battery volume 16. The partition 8 has above it an upper passage 14 allowing the fluid filling the battery volume 16, after exceeding the level of the sensor 12, to flow towards the filling volume 10.

[0026] A worm screw 20 arranged horizontally along a main axis, in the filling volume 10, has at one end called by convention front end, a rotating bearing 22 for fixing to the casing 4, its rear end being engaged in a nut 24 fixed to the partition 8 which is movable horizontally along the axis of this screw.

[0027] An electric motor 26 drives the worm screw 20 through a reduction gear, which, by engaging with the nut of the partition 24, allows the partition mounted on axial slides to move forward. A front stop 38 fixed to the bottom of the filling volume 10 limits the maximum axial displacement of the partition 8 when it is driven by the worm screw 20.

[0028] A hollow rod 30 arranged parallel to the threaded rod 20 has its rear end fixed to the partition 8, its front end having a point 32 which protrudes from the box 4, just after the passage of a dynamic seal allowing this rod to slide out of this box.

[0029] The hollowed rod 30 has a rear lateral drilling 34 located near the partition 8, and a front lateral drilling 36 located behind its front tip 32, remaining in the filling volume 10 in the rest position shown in [Fig.1].

[0030] The vehicle includes, beside the battery box 2, forward of the front tip 32 of the hollow rod 30, and at a short distance from this tip, a chassis member 40 of the vehicle, forming a closed hollow body with a significant volume. The chassis member 40 has on its side a breakable plug 42 closing a passage, positioned opposite the tip of the hollow rod 32, with a safety distance that prevents contact between these two elements in all operating conditions of the vehicle.

[0031] Following a fire in battery 2, an operator began filling the container 4 through the upper supply conduit 6 which opens directly into the first battery volume 16. The extinguishing fluid has a low level NB which is not detected by the level threshold sensor 12.

[0032] Figure 2 shows the supply conduit 6 which continues to supply the housing of battery 4 with the extinguishing fluid, this fluid reaching the high level NH exceeding the level threshold sensor 12, corresponding to above the partition 8. In this case the level threshold sensor 12 sent a signal to an electric motor control device 26, which by its reducer drives the worm screw 20 in rotation by moving the partition 8 forward.

[0033] As the hollow rod 30 moves forward along with the partition 8, its front tip 32 crosses the safety distance to reach the obturator 42 presenting the breakable material, and pierces it. The worm gear 20 continues its rotation to achieve sufficient displacement of the partition 8, bringing the front lateral bore of the rod 36 inside the spar 40, and finally coming to rest on the front stop 38.

[0034] The shutter 42 allows the spar 40 to be kept closed in normal use to prevent in particular the introduction of moisture inside.

[0035] A passage of fluid is automatically obtained at the high level NH of the battery volume 16, which pours over the partition 8 towards the filling volume 10, then enters the hollowed rod 30 through its rear lateral bore 34, then exits through its front lateral bore 36 in order to flow into the longitudinal member 40.

[0036] In this way, by an automatic process, while the operator continues to fill the battery box 4 through the supply conduit 6, a flow of cold extinguishing fluid is obtained which passes through the battery box 4, making it possible to maintain a low temperature of this battery 2, and then to recover this fluid in an external volume which is near this box.

[0037] In general the invention applies to all types of traction battery boxes for motor vehicles presenting fire risks, having a possibility of supplying this box with an extinguishing fluid.

[0038] The automatic opening device of the battery box outwards, using in this example a rod 30 comprising a rear bore 34 and a front bore 36 to remove the fluid from the box 4, driven by a motor 26, may alternatively include any other system, such as for example a controlled valve.

[0039] The longitudinal member 40, forming an external fluid recovery volume, allows the use of available space in the vehicle body located next to the battery box 4, which represents an economical solution. Alternatively, any other type of reservoir can be used, in particular a specific reservoir designed to receive this fluid. Recovering the fluid in a closed volume then allows it to be treated. According to the invention, an automatic opening device for the box, which allows the fluid to flow outwards, can be provided more simply.

Claims

Demands

1. Electric or hybrid motor vehicle traction battery system, comprising a battery (2) disposed in a closed box (4) having an external inlet (6) for supplying fire extinguishing fluid, characterized in that it includes a means for detecting (12) a fluid level threshold in the battery box (4), an automatic device for opening this box (4) outwards as a function of the detection of this threshold, and the box opening device (4) includes a hollow rod (30) which slides in a wall of this box (4), after detection of the fluid level threshold.

2. Battery system according to claim 1, characterized in that the automatic opening device of the box (4) when activated puts this box (4) in communication with an external volume (40) to transfer this fluid to it.

3. Battery system according to claim 1, characterized in that the hollowed rod (30) has a front tip (32) exiting the casing (4) which, when it slides, enters the outer volume (40) by passing through a shutter (42) closing this volume (40).

4. Battery system according to claim 3, characterized in that the hollowed rod (30) has a front lateral bore (36) which after sliding entered the outer volume (40) to pour the fluid into it.

5. Battery system according to any one of claims 1 to 4, characterized in that it comprises a worm screw (20) driven by a motor (26) which performs the sliding of the hollow rod (30).

6. Battery system according to any one of the preceding claims, characterized in that the detection means (12) comprises a level sensor disposed in the upper part of the casing (4).

7. Battery system according to any one of the preceding claims, characterized in that the casing (4) comprises a battery volume (16) including the battery (2) and the external inlet (6), and a filling volume (10) separated by a movable partition (8) which moves to enlarge this battery volume (16) when the automatic opening device of the casing (4) is actuation, allowing fluid to be poured over this partition (8) into the filling volume (10).

8. Electric or hybrid motor vehicle equipped with a traction battery (2) of this vehicle, characterized in that this battery (2) contained in a casing (4) is part of a battery system according to any one of the preceding claims.

9. Motor vehicle according to claim 8, characterized in that it comprises a side member of the vehicle body forming an external volume (40) receiving the fluid after the actuation of the automatic opening device of the box (4).

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