Heat-melting cap

Abstract

The present invention relates to a device (2) for extinguishing a fire inside an electric storage device (1) of a vehicle, the device (2) comprising at least one cap (10) and a cylinder (12) containing at least one gas for extinguishing the fire, the cylinder (12) having a closure seal (20) and defining a space (14) for containing the gas, the cap (10) comprising at least one perforation device (22) and a base (24) provided with a perforated wall (26), the perforation device (22) being capable of destroying the closure seal (20) of the cylinder (12) while maintaining the airtightness of the cylinder.

Description

Summary of the Invention

[0001] The present invention relates to a fire extinguishing device, and more particularly to a device for extinguishing a fire in a vehicle power storage device.

[0002] Electrical storage devices, otherwise known as batteries, are commonly used in hybrid and / or electric vehicles. Such electrical storage devices can, for example, power an electric motor carried on board the motor vehicle. However, batteries can be susceptible to ignition, for example, if the vehicle is destroyed or a vehicle fire occurs as a result of a road traffic accident. Thus, for example, in a vehicle fire, there is an extremely large heat release in the vicinity of the battery, which can potentially trigger a thermal runaway phenomenon in the electrochemical cells present in the battery.

[0003] Thus, the use of a device for extinguishing a fire spreading inside an electrical storage device is known, comprising at least one bottle filled with at least one gas capable of stopping the spread of the fire. In particular, document EP 2 556 857 A1 discloses a bottle of gas whose sealing membrane is pierced by means of a needle, which is activated under the effect of melting a heat-sensitive member that arrests the needle.

[0004] One drawback of such fire extinguishing devices is that they are expensive to implement and require regular maintenance, among other things. It is therefore an object of the present invention to simplify the use of fire extinguishing devices by making their operation, i.e., the release of gas capable of stopping the spread of fire, entirely mechanical and reducing the number of parts required for this operation.

[0005] The present invention therefore relates to a fire extinguishing device for extinguishing a fire in a vehicle's electrical storage device, comprising at least one cap and at least one bottle containing at least one extinguishing gas, the bottle having a sealing membrane and defining a space for containing the gas, and the cap comprising at least one perforation device, characterized in that the perforation device is at least partially made from a heat-melting material and the cap can be fixed to the bottle in such a way that the perforation device tears open the sealing membrane of the bottle and the cap hermetically seals the space in the bottle.

[0006] The device for extinguishing a fire in an electric storage device, or in other words, a battery, can be used in electric and / or hybrid motor vehicles, but also in stationary electric storage installations. Such batteries can, in particular, power an electric motor housed in the vehicle and thereby enable the vehicle to move. In this case, the fire extinguishing device has the purpose of suppressing the spread of a fire in the electric storage device. To this end, the fire extinguishing device comprises at least a bottle of gas and a cap capable of hermetically sealing the space in the bottle, which simultaneously allows the gas to escape under the influence of at least one environmental parameter, in this case the temperature of the air inside the electric storage device.

[0007] It will be appreciated that the perforation device of the cap is then able, on the one hand, to rupture the sealing membrane and release the gas contained in the space of the bottle, and, on the other hand, to prevent this gas from escaping out of the bottle, i.e. towards the environment outside said space. Such airtight sealing of the space of the bottle is then at least partly effected by the perforation device.

[0008] According to one aspect of the invention, a perforation device includes at least one body and a tip, both of which contain a hot melt material.

[0009] It will be appreciated that the point functions to rupture the sealing membrane of the gas bottle and is configured to extend at least partially into the space of the bottle when the sealing membrane is ruptured. It will be further appreciated that when the point extends into the space of the bottle, it cooperates with the body to contribute to sealing the space of the bottle.

[0010] In this case, the term "thermofusible material" means that the material is heat-sensitive, i.e., capable of changing state under the influence of heat, in particular from a solid state to a liquid state, i.e., capable of melting under the influence of heat at least above a threshold temperature, e.g., 80°C.

[0011] According to non-limiting examples of the present invention, the body and tip may be fabricated from polyethylene, polypropylene, polyamide, polybutylene terephthalate, and / or polyacrylonitrile butadiene styrene.

[0012] According to one feature of the invention, the cap comprises a base provided with a perforated wall capable of allowing gas to pass therethrough, the base containing at least one heat-resistant material, the perforated wall being arranged around the body of the perforation device, and the base comprising at least one fastening means for fastening the cap to the bottle.

[0013] The base of the cap then contributes to holding the piercing device in place on the bottle, so that the piercing device hermetically seals the bottle. Heat-resistant material means that the base can withstand high temperatures, in particular higher than the melting point temperature of the hot-melt material from which the piercing device is made. In other words, the base has a melting point temperature higher than, for example, 250°C. According to one embodiment of the invention, the entire base is made of heat-resistant material.

[0014] According to some non-limiting examples of the present invention, the heat resistant material may be a polyetheretherketone, polyimide, and / or epoxy based synthetic material.

[0015] By perforated wall is meant that the wall comprises at least one opening formed in its thickness, thereby communicating the interior space of the base with the environment outside the base. It will be understood that when at least a portion of the perforation device melts, the perforated wall thereby allows gas to pass from the space in the bottle into the environment outside the bottle. According to one example of the invention, the wall may comprise a plurality of openings extending around the periphery of the base.

[0016] According to an exemplary embodiment of the invention, the fixing means extend around the periphery of the point of the drilling device.

[0017] According to one feature of the invention, the base comprises at least one fixing wall arranged around the point of the perforation device, and the fixing means belonging to the cap is a thread formed on the fixing wall, which can cooperate with a complementary thread formed on the bottle.

[0018] The perforated wall is extended by a fixing wall provided with fixing means, which in this case are for example internal or external threads. According to one example, the fixing wall has an inner surface facing the point of the drilling device, and the internal thread is formed on said inner surface of the fixing wall.

[0019] The bottle comprises an opening intended to be covered by a sealing membrane before the cap is fitted to the bottle, the opening being made in particular at the end of the neck of the bottle, where it will be understood that a complementary thread is formed on the outer periphery of the neck of the bottle so that it can cooperate with a thread on the fixing wall of the base of the cap.

[0020] It will then be understood that in this exemplary embodiment of the invention, the cap is screwed onto the bottle so that the point tears open the sealing membrane, and the cap is held on the bottle by means of a screw thread and a complementary screw thread to cooperate with the piercing device to ensure an airtight seal of the body space.

[0021] According to an alternative embodiment of the invention, the securing means for securing the cap to the bottle is a press fit of the base onto the bottle.

[0022] According to one example of the invention, the inner surface of the retaining wall may include an additional thickness extending around the periphery of the piercing device point, which additional thickness contributes to retaining the cap on the bottle, or in other words, to reducing the circumference defined by the retaining wall, thereby contributing to a press fit of the cap onto the bottle.

[0023] In accordance with one aspect of the present invention, a sealing gasket is disposed around the periphery of the tip of the piercing device.

[0024] It will be appreciated that the sealing gasket improves the airtightness of the seal of the bottle cavity by the cap, particularly when the cap is press-fit onto the bottle.

[0025] According to one feature of the invention, the drilling device contains at least 5% mineral material.

[0026] The mineral material that at least partially constitutes the perforating device allows for an increase in the hardness of the perforating device, thereby enhancing the ability of the perforating device to rupture the sealing membrane without adversely affecting the thermal melting properties of the perforating device.

[0027] According to one aspect of the invention, the gas bottle contains at least part of carbon dioxide, which has excellent properties, among other things, that allow it to extinguish a fire that spreads inside the storage device by expelling at least part of the oxygen present in the device.

[0028] According to one feature of the invention, the perforation device has a melting point temperature above at least 80°C. At 80°C or above, the perforation device passes from a solid state to a liquid state, thereby allowing gas to escape from the space in the bottle to the environment outside the bottle, in particular by means of the perforated wall of the base. According to one example, the melting point temperature of the perforation device is above 80°C. Advantageously, the melting point temperature of the perforation device is below 120°C.

[0029] The invention also relates to an electrical storage device for a motor vehicle, comprising at least one peripheral wall and at least one fire extinguishing device according to the above characteristics.

[0030] The power storage device, otherwise known as a battery pack, is used in particular in so-called hybrid or all-electric vehicles to power at least one electric motor, and the peripheral wall then serves to define a space in which the power storage cells that make up the power storage device are housed.

[0031] According to one feature of the electrical storage device, the fire extinguishing device is housed within the peripheral wall. More specifically, at least one cavity is formed within the thickness of the peripheral wall of the electrical storage device, and the fire extinguishing device is housed within the cavity.

[0032] According to one example, the cavity opens into one edge of the peripheral wall.

[0033] According to one feature of the storage device, the peripheral wall comprises at least one notch, the cap comprises a base provided with a perforated wall capable of allowing gas to pass therethrough, and the perforated wall of the base of the cap of the fire extinguisher is positioned facing the notch.

[0034] It will be understood that the notch is formed in the cavity that accommodates the fire extinguishing device, and the notch is formed facing the perforated wall of the cap. In other words, the notch connects the cavity space with the internal space of the storage device in which the electric cell is located. Such a feature is effective in enabling enhanced diffusion of gas from the gas bottle into the internal space of the storage device.

[0035] The present invention further relates to a method for assembling a fire extinguishing device according to the above characteristics, comprising at least one step of placing a cap against the sealed sealing membrane of a bottle, and then, in at least one subsequent step, the cap is fixed to the bottle by a fixing means such that a piercing device tears open the sealing membrane, the cap then hermetically sealing the space of the bottle.

[0036] It will therefore be appreciated that the combination of the structure of the perforation device and the restraint of the cap by the cap's fixing means ensures an airtight seal of the gas bottle. It will further be appreciated that the melting of the perforation device containing the hot melt material ensures the passage of gas from the space in the bottle to the space outside the base, in this case the interior space of the storage device, thereby enabling the extinguishing of a fire.

[0037] Further features, details and advantages of the invention will appear more clearly from a reading of the description given below, taken as a guide in conjunction with the drawings, in which: [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a diagram showing the overall configuration of a power storage device equipped with a fire extinguishing device according to the present invention; [Figure 2] 2 is a schematic diagram of the fire extinguishing device of FIG. 1, including at least one cap and a gas bottle. [Figure 3] 2 is a diagram showing the overall configuration of the cap of the fire extinguisher of FIG. 1. FIG. [Figure 4] 2 is a schematic longitudinal section of the cap of the fire extinguishing device of FIG. 1, comprising at least one fastening means for fastening to the bottom, according to a first exemplary embodiment; [Figure 5] 2 is a schematic longitudinal section of the cap of the fire extinguishing device of FIG. 1, comprising at least one fastening means for fastening to a bottle according to a second exemplary embodiment; [Figure 6] 2 is a schematic diagram of at least a portion of fitting the cap of the fire extinguisher of FIG. 1 onto the bottle of the fire extinguisher. [Figure 7] 2 is a schematic view of the fire extinguishing device of FIG. 1, with the perforating device in a molten state. DETAILED DESCRIPTION OF THE INVENTION

[0039] It should first be noted that the drawings explain the invention in detail with respect to its implementation, and that these drawings, where applicable, can, of course, serve to better define the invention. It should also be noted that these drawings illustrate only exemplary embodiments of the invention. Finally, the same reference numerals refer to the same elements throughout all the drawings.

[0040] 1 shows an electrical storage device 1, for example in a motor vehicle, which stores a fire extinguishing device 2 according to the invention. The electrical storage device 1, otherwise known as a battery pack, can be used in particular in hybrid or electric motor vehicles, for which the electrical storage device supplies power to at least one electric motor (not shown), which enables the vehicle to move.

[0041] The electrical storage device 1 comprises at least one peripheral wall 4 defining a space 6 of the electrical storage device, which may house, for example, a battery (not shown). As can be seen in Figure 1, the peripheral wall 4 of the electrical storage device 1 comprises at least one cavity 8 formed within the thickness of the peripheral wall, and a fire extinguishing device 2 according to the present invention is housed within the cavity 8.

[0042] The fire extinguishing device 2 has a function of, among other things, releasing at least one fire extinguishing gas to at least prevent the spread of a fire within the electricity storage device 1. More specifically, the gas may be, for example, at least carbon dioxide, which can fill the space 6 of the electricity storage device 1 and thereby reduce the amount of oxygen available for the fire, thereby suppressing the spread of the fire.

[0043] The fire extinguisher 2, which can be seen in Fig. 2 in an unassembled configuration, comprises at least one cap 10 and at least one bottle 12 containing at least extinguishing gas. More specifically, the bottle 12 of the fire extinguisher 2 defines a space 14 into which the gas enters. The gas bottle 12 extends mainly in a longitudinal direction L and comprises at least one opening 16 at one longitudinal end 18 of the gas bottle. It will be understood that the opening 16 is intended, on the one hand, to allow gas to enter the space 14 of the bottle 12 and, on the other hand, to allow the gas to exit under certain environmental conditions, which will be described in more detail below, in particular when the fire extinguisher 2 is housed in an electrical storage device.

[0044] 2, the space 14 of the gas bottle 12 is closed using a sealing membrane 20 that covers the opening 16 of the gas bottle 12. It will therefore be understood that the sealing membrane 20 functions to prevent gas from escaping from the space 14 of the bottle 12. According to one non-limiting example of the present invention, the sealing membrane 20 is an easily rupturable sheet such as aluminum or alternatively a thin film of plastic-coated paper.

[0045] The cap 10 of the fire extinguisher 2 comprises at least one piercing device 22 and a base 24 provided with a perforated wall 26. The piercing device 22 thereby serves, on the one hand, to rupture the sealing member 20 of said bottle 12, and, on the other hand, to cooperate with the base 24 of the cap 10 to at least partially seal the bottle 12 in an airtight manner once the sealing membrane 20 has been ruptured. In this case, airtight sealing means that the cap 10 prevents gas in the bottle 12 from escaping from the bottle space 14 towards the space of the storage device. Such cooperation between the cap 10 and the bottle 12 will be explained later in more detail, in particular in relation to FIG. 6.

[0046] The cap 10 will now be described in more detail with reference to Figures 3-5.

[0047] The perforation device 22 of the cap 10 includes at least one body 28 and at least one tip 30 extending from the body 28 of the cap 10. More specifically, the tip 30 extends from the body 28 of the cap 10 in the longitudinal direction L of the gas bottle 12. Therefore, it will be understood that the perforation device 22 has an elongated shape in the longitudinal direction L of the bottle 12. According to an example of the present invention, the body 28 of the perforation device 22 has a cylindrical shape that can set a central axis of rotation C parallel to the longitudinal direction L of the bottle. As a result, the tip 30 has a conical shape with one end forming a beveled surface of the cone located on the central axis C of the body 28, at the end opposite the body.

[0048] According to the invention, both the body 28 and the tip 30 of the perforation device 22 contain a thermofusible material. Advantageously, the body 28 and the tip 30 of the perforation device 22 are made entirely from a thermofusible material. By thermofusible material, it is meant that the body 28 and the tip 30 of the perforation device 22 are capable of transitioning from a solid state to a liquid state under the effect of a certain temperature. That is, the body 28 and the tip 30 soften when the temperature reaches at least a threshold temperature, and then melt when the temperature reaches at least the melting point temperature. The melting point temperature above which the body 28 and the tip 30 melt is in this case at least 80°C. Therefore, when the temperature present in the storage device space reaches at least the melting point temperature of the body 28 and the tip 30, these elements change state as described above.

[0049] According to non-limiting examples of the present invention, body 28 and tip 30 may be fabricated from polyethylene, polypropylene, polyamide, polybutylene terephthalate, and / or polyacrylonitrile butadiene styrene.

[0050] According to one embodiment of the present invention, the body 28 and the tip 30 may contain at least 5% mineral material. In this case, the mineral material that at least partially constitutes the body 28 and the tip 30 has the effect of strengthening the structure of these elements, in particular, hardening them. Such a composition containing at least 5% mineral material further exhibits the advantage of maintaining the heat-melting properties of the body 28 and the tip 30 of the perforation device 22. The rigidity provided by the incorporation of the mineral material ensures that the sealing membrane 20 is pierced by the tip 30 when the cap 10 is assembled with the bottle 12.

[0051] The base 24 of the cap 10 comprises at least a perforated wall 26 and at least one fixed wall 32. More specifically, the perforated wall 26 of the base 24 is located around the body 28 of the piercing device 22, while the fixed wall 32 is disposed around the tip 30 of the piercing device 22. It will be understood that the perforated wall 26 of the base 24 then extends around the body 28 of the piercing device 22 at a first non-zero distance D1 from the body 28, primarily in the longitudinal direction L of the bottle, the first distance D1 being taken in a radial direction of the body relative to the central axis C of the body 28, as can be seen in FIG.

[0052] In this case, perforated wall 26 means that the wall has at least one opening 34 therethrough. More specifically, as shown in this example of the invention, perforated wall 26 has a plurality of openings 34 extending around the periphery of body 28 of perforation device 22.

[0053] The fixed wall 32 of the base 24 extends around the tip 30 of the perforation device 22, primarily in the longitudinal direction L of the bottle. More specifically, the fixed wall 32 extends, at least in part, a second non-zero distance D2 from the tip 30, the second distance D2 being taken in a radial direction of the body 28 relative to the central axis C of the body 28. It will be appreciated that, due to the conical shape of the tip 30, the second distance D2 separating the tip 30 from the fixed wall 32 increases with increasing distance from the body 28 of the perforation device 22 in the longitudinal direction L of the bottle. Furthermore, the second distance D2 is certainly less than the first distance D1 separating the body 28 of the perforation device 22 from the perforated wall 26.

[0054] A first end 36 of the cap 10 and a second end 38 of the cap 10 are defined, which are opposite each other in the longitudinal direction L of the gas bottle, whereby the first end 36 corresponds to the end located at the level of the perforated wall 26 of the base 24, and the second end 38 corresponds to the end located at the level of the fixed wall 32 of the base 24.

[0055] An end disk 40 of the base 24 is disposed at the first end 36 of the cap 10. The end disk 40 is then configured to close the first end 36 of the cap 10, such that the plurality of openings 34 constitute the only means of fluid communication between the interior space of the cap defined by the perforated wall 26 and the environment external to the cap 10. The end disk 40 has an outer peripheral edge 41 with an end disk radius R1 at least equal to the wall radius R2 defined by the perforated wall 26, the outer end disk radius R1 and the wall radius R2 being defined relative to the central axis C of the body 28 of the perforation device 22. It will thus be understood that the end disk 40 is disposed at the first end 36 of the cap 10 so as to cover one end of the perforated wall 26.

[0056] It will further be appreciated that when the temperature within the electrical storage device space reaches at least the melting point temperature, the perforation device 22 melts and allows gas to flow towards the openings 34 .

[0057] The base 24 of the cap 10 further comprises at least one connecting disc 44 disposed between the perforated wall 26 and the fixed wall 32 of the base 24. In other words, the connecting disc 44 extends radially from the outer periphery of the perforation device 22 along the central axis C of the body to connect the perforated wall 26 to the fixed wall 32. The connecting disc 44 further comprises a circular hole 46 having an inner peripheral edge 48 extending around the body 28 of the perforation device 22. The inner peripheral edge 48 is fitted particularly closely around the body 28 such that the inner peripheral edge 48 and the body 28 are in contact with each other, i.e., at a first distance D3 of zero measured in the radial direction of the body 28 relative to the central axis C of the body. According to the illustrated example of the invention, the connecting disc 44 has a connecting disc radius R3 at least equal to the wall radius R2 defined above, measured between the central axis C and an outer edge 50 of the connecting disc 44.

[0058] It will therefore be understood from the above that the particular arrangement of the connecting discs 44 around the body 28 of the perforating device 22 makes it possible to prevent the flow of gas between the space defined by the fixed wall 32 and the space defined by the perforated wall 26.

[0059] According to the present invention, the base 24 of the cap 10 contains at least one heat-resistant material. In this case, heat-resistant material means that the base 24 can withstand high temperatures certainly higher than the melting point temperature of the perforation device 22 described above. More specifically, the heat-resistant material according to the present invention can withstand temperatures at least higher than 250°C, a temperature that should never be reached because the perforation device would melt before reaching that temperature, thereby extinguishing the fire. According to non-limiting examples of the present invention, the heat-resistant material may be a polyetheretherketone, polyimide, and / or epoxy-based plastic material.

[0060] According to one feature of the invention, the heat-resistant material of the base 24 of the cap 10 may contain a mineral material, which at least partially constitutes the base 24, making it possible to improve the mechanical properties of this base and its ability to withstand high temperatures.

[0061] Furthermore, according to the present invention, the base 24 comprises at least one fastening means 52 for fastening the cap 10 to the gas bottle 12. That is to say, according to a first example of the present invention, as seen in Fig. 4, the fastening means 52 belonging to the cap 10 is a thread 54, in this example an internal thread, formed on the fastening wall 32 of the base 24. More specifically, the inner surface 56 of the fastening wall 32 is defined as the face of the fastening wall 32 facing towards the point 30 of the perforation device 22. In that case, the inner surface 56 comprises at least a thread 54 capable of cooperating with a complementary thread 58 formed on the opening 16 of the bottle 12, as seen in Fig. 2. In that case, the complementary thread 58 is made on the outer periphery of the neck 59 of the bottle 12.

[0062] According to a second example of the fastening means 52, visible in Figure 5, the fastening of the cap 10 to the gas bottle 12 is a force fit of at least the fastening wall 32 onto the neck 59 of the bottle. In the remainder of the description, only the features that differ between the second and first embodiments, and in particular the fastening means 52, are to be considered to be described in detail. For elements common to both, reference is made to the above description.

[0063] An additional thickness 60 extends circumferentially from the inner surface 56 of the retainer wall 32. More specifically, the additional thickness 60 extends from the inner surface 56 at the second end 38 of the cap 10 around the periphery of the cusp 30 of the piercing device 22. As a result, the additional thickness 60 functions to reduce the inner diameter T1 of the retainer wall 32, thereby enabling the retainer wall 32 to be press-fit onto the neck 59 of the bottle 12, the neck 59 having a neck diameter T2, as viewed in FIG. 2, that is substantially larger than the inner diameter T1 of the retainer wall 32.

[0064] 5, a sealing gasket 62 can be disposed in the space defined by the fixed wall between the additional thickness 60 of the fixed wall and the connecting disc 44. More specifically, the sealing gasket 62 extends around the periphery of the point 30 of the piercing device 22. It will be understood that the sealing gasket 62 therefore contributes to ensuring airtightness between the space of the bottle and the space defined by the base 24 when the cap 10 is secured to the bottle.

[0065] Next, a method for assembling the fire extinguishing device 2 will be explained in more detail with reference to FIGS.

[0066] In an initial state in which the cap 10 and gas bottle 12 described above are separated from each other as seen in Figure 6, the sealing membrane 20 of the bottle 12 forms a fluid-tight seal that seals the space 14 of the bottle 12 that contains the gas. In that case, the method includes at least one step of aligning the cap 10 with the opening 16 of the bottle 12 that carries the sealing membrane 20. More specifically, the second end 38 of the cap 10 is aligned with the opening 16 of the gas bottle 12, thereby positioning the tip 30 of the perforation device 22 against the sealing membrane 20 of the bottle 12.

[0067] Thereafter, in a further step, the cap 10 is secured to the opening 16 of the bottle 12 by means of the securing means 52 formed on the fixing wall 32 of the base 24. That is, where the securing means 52 correspond to the threads 54 formed on the inner surface 56 of the fixing wall 32, the cap 10 is screwed onto the neck 59 of the bottle 12 using the complementary threads 58 formed on the neck 59. More specifically, the cap 10 is screwed onto the neck 59 at least until the point 30 of the piercing device 22 ruptures the sealing membrane 20 disposed across the opening 16 of the bottle 12.

[0068] The unique structure of cap 10, particularly the seal between the space defined by fixed wall 32 and the space defined by perforated wall 26, ensures that gas bottle 12 remains sealed. In other words, even though sealing membrane 20 of bottle 12 is ruptured, allowing gas to pass through opening 16 of said bottle 12, the structure of cap 10 and its retention in place on neck 59 ensures that said bottle 12 remains hermetically sealed.

[0069] According to an alternative configuration of the extinguishing device, provision can be made for the cap to be fixed to the bottle in such a way that the piercing device completely seals the opening of the bottle, i.e. the point of the piercing device extends into the space of the bottle until it hits the edge of the bottle that defines the opening, thereby strengthening the airtight seal of the gas bottle.

[0070] When the fire extinguishing device 2 is placed in the cavity 8 of the electrical storage device 1 as seen in Figure 1, an increase in temperature within the space 6 of the electrical storage device 1 to at least the melting point temperature results in melting of the piercing device 22. In that way, the change in state of the piercing device 22 from a solid state to at least a liquid state results in changing the sealing properties of the cap 10.

[0071] 7 results in the melting of the perforation device, particularly at the connecting disk 44 and the circular holes 46 therein, allowing gas to flow. Specifically, the melting of the perforation device creates a gap between at least the inner periphery 48 and the perforation device 22, and the gap between these elements widens as the perforation device further melts. In other words, the inner periphery 48 of the circular holes 46 and the perforation device 22 are no longer in contact with each other.

[0072] In this case, it will be understood that the openings 34 formed in the perforated wall 26 have the function of allowing gas that has passed through the circular holes 46 in the connecting disc 44 to diffuse out of the cap 10.

[0073] According to an advantageous feature of the invention, which can be seen in Figure 1, the peripheral wall 4 of the storage device 1 comprises at least one notch 64 opening into the cavity 8 accommodating the fire extinguisher 2, said notch 64 being formed at least partially facing the perforated wall of the base of the fire extinguisher 2. This consequently facilitates the diffusion of gas from the space of the bottle towards the space 6 of the storage device 1.

[0074] It will be understood that the assembly method and structural and functional features of cap 10 just described with reference to Figures 6, 7 and 1 apply mutatis mutandis when the fastening means is a press fit of the cap onto the opening of the gas bottle, as described in Figure 5.

[0075] The fire extinguishing device as just described is advantageous in that it makes it possible, by means simple and inherent to its construction, to hermetically seal the space of the bottle containing the gas when the storage device is under normal operating conditions, i.e. when the temperature is below the melting point temperature of the perforation device, while at the same time making it possible to release gas into the space of said storage device when the temperature exceeds the melting point temperature of the perforation device.

[0076] However, the invention should not be limited to the means and forms exclusively described and exemplified, but also applies to any equivalent means or forms and to any combination of such means or forms.

Claims

1. 1. A fire extinguishing device (2) for extinguishing a fire in an electric storage device (1) of a vehicle, comprising at least one cap (10) and a bottle (12) for containing at least one extinguishing gas, the bottle (12) having a sealing membrane (20) and defining a space (14) for containing the gas, the cap (10) comprising at least one perforating device (22), characterized in that the perforating device (22) is at least partially made of a heat-melting material, and the cap (10) can be fixed to the bottle (12) such that the perforating device (22) tears open the sealing membrane (20) of the bottle (12) and the cap (10) hermetically seals the space (14) of the bottle (12).

2. 2. The fire extinguishing device (2) of claim 1, wherein the perforating device (22) comprises at least one body (22) and a point (30), both of which contain a heat-melting material.

3. 3. The fire extinguishing device (2) of claim 2, wherein the cap (10) comprises a base (24) provided with a perforated wall (26) capable of allowing the gas to pass therethrough, the base (24) containing at least one heat-resistant material, the perforated wall (26) being arranged around the body (28) of the perforating device (22), and the base (24) comprising at least one fastening means (52) for fastening the cap (10) to the bottle (12).

4. 4. The fire extinguishing device (2) according to claim 3, wherein the base (24) comprises at least one fixing wall (32) arranged around the point (30) of the piercing device (22), and the fixing means (52) belonging to the cap (10) is a screw thread (54) formed on the fixing wall (32) and capable of cooperating with a complementary screw thread (58) formed on the bottle (12).

5. 4. The fire extinguishing device (2) according to claim 3, wherein the fastening means (52) for fastening the cap (10) to the bottle (12) is a press fit of the base (24) onto the bottle (12).

6. 6. Fire extinguishing device (2) according to any one of claims 1 to 5, wherein the perforating device (22) contains at least 5% mineral material.

7. An electrical storage device (1) for a motor vehicle, comprising at least one peripheral wall (4) and at least one fire extinguishing device (2) according to any one of claims 1 to 6.

8. The electrical storage device (1) according to claim 7, wherein the fire extinguishing device (2) is housed within the peripheral wall (4).

9. 9. The storage device (1) according to claim 7 or 8, wherein the peripheral wall (4) comprises at least one notch (64), the cap (10) comprises a base (24) provided with a perforated wall (26) capable of allowing the gas to pass through, and the perforated wall (26) of the base (24) of the cap (10) of the fire extinguisher (2) is arranged facing the notch (64).

10. 7. A method for assembling a fire extinguishing device (2) according to any one of claims 1 to 6, comprising at least one step of positioning the cap (10) facing the sealed sealing membrane (20) of the bottle (12), and then, in at least one subsequent step, fixing the cap (10) to the bottle (12) by fixing means (52) so that the perforating device (22) tears open the sealing membrane (20), whereby the cap (10) hermetically seals the space (14) of the bottle (12).

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