VENTILATION DEVICE WITH METALLIC PERMEABLE MEDIA FOR BATTERY HOUSING(S), AND ASSEMBLY METHOD

Abstract

The battery case ventilation device (1) includes a mounting body (2) forming or associated with an opening rim of the case, a channel (C2) in the body, optionally a permeable membrane (5) sealing the channel, and a cover (3). The channel guides a gaseous exhaust from inside the case. A metallic filter medium (8; 108), typically a flexible fibrous layer or textile, provides fire protection by being positioned below the body (2) opposite the cover. The medium (8) includes a flexible fabric or layer (ML) of metallic yarns or fibers to filter the gases and separate solid particles. By sealing the channel (C2) from below, the medium (8) forms a thermally resistant barrier, allowing only a purified fluid flow, free of solid particles, to pass through the channel, particularly when the gaseous exhaust temperature exceeds 500°C. (See abstract figure: Figure 1)

Description

Title of the invention: VENTILATION DEVICE WITH METALLIC PERMEABLE MEDIA FOR BATTERY HOUSING(S), AND ASSEMBLY METHOD Technical field

[0001] This disclosure relates to the field of battery systems, particularly ventilation equipment enabling pressure compensation for batteries. More specifically, the invention relates to a device, mounted on the casing of a battery / power supply, which enables pressure compensation by providing protection in the form of a metallic filter medium, and a method for assembling such a device. Technological background

[0002] A pressure compensation device is known from US patent 11245156. This device includes a perforated base, a cover, and a porous membrane positioned beneath the base to allow the passage of gases trapped within a battery module, such as a battery module in a vehicle. In the event of instability (excessive internal pressure), the membrane under the cover rises to such a point that a point on the base of the compensation device pierces the membrane, allowing the gas to escape at a significantly higher flow rate. Numerous openings are provided in the cover for the significant exhaust of air. A protective screen, in the form of a rigid grid, is positioned beneath the membrane and secured by anchoring screws.

[0003] Such a device, using a clip-on fitting, does not allow the cover to be ejected in the event of a rupture / puncture of the membrane. In this case, the plastic cover and the plastic base heat up very quickly. It has been observed that temperatures can reach high values, well exceeding 500°C, for example, around 900 or 1000°C. At this heat level, even plastics approved for battery case ventilation devices melt rapidly, which can cause detachment or disintegration of the parts that will block all or part of the openings formed by the rigid grille (very rapid and significant blockage of this underlying grille). In practice, with incandescent particles, fine molten metal particles, and / or combustible materials escaping from the case through the grille, flames can ignite and the fire is likely to spread within the vehicle.

[0004] There is therefore a need for ventilation devices of simple design, preventing the spread of fire in the event of thermal runaway, and usable effectively for the pressure compensation of batteries. Summary

[0005] This disclosure improves the situation.

[0006] To this end, a ventilation device for a battery case is proposed, in particular for a case comprising one or more batteries, the device comprising: - a body, for example forming a connector; - a channel, provided in the body to guide a gaseous flow escaping from the casing through the opening (typically along a longitudinal axis of the channel); - a filling part, attached to the body, preferably made in the form of a hood which is perforated so as to be able to cover the canal on a side opposite to the opening;and - a metallic fire-resistant filter medium carried by or covering the body in an arrangement underlying the body opposite the sealing part, the metallic filter medium including a (typically flexible) fabric or layer of gas-permeable metallic wires or fibers and sealing the channel from below, thereby the metallic filter medium forming a barrier (with a solid particle barrier effect) to allow only a purified fluid flow without solid particles to pass into the channel, particularly in the event of the escape, from the housing, of a gaseous flow with a very high temperature, for example exceeding 500°C (with the medium possibly having a structure comprising steel or essentially made of steel, for example steel resistant to temperatures of at least 600°C).

[0007] Thanks to these provisions, effective fire protection can be advantageously achieved by obtaining a barrier effect against incandescent particles which, in the event of a failure to cover the channel, could be propelled directly from inside the housing to the outside. Moreover, unlike grid structures (with openings of around 1 or 2 mm in width, stopping only 25 to 35% of particles), we ensure that all solid particles are stopped.

[0008] The metallic filter medium may exhibit high permeability to the gas flow (relative gas permeability), for example by including a layer of very fine metallic fibers or filaments, for example, submillimeter in diameter (or a characteristic parameter equivalent to the diameter). The metallic medium(s) may have fibers with a diameter close to one millimeter, particularly to withstand high temperatures (up to 1 mm in diameter).

[0009] The metallic filter medium constitutes a layer (homogeneous or possibly composed of sub-layers) that is flexible or capable of having a corrugated profile. More generally, the metallic filter medium is composed, at least 95% by mass, of metal wires and / or fibers, the metal preferably being steel. Interstices between the wires or fibers may form pores of submillimeter size, for example, exceeding 100 microns, or possibly exceeding 1 mm in certain cases. The mesh or layer, which forms pores within the flexible metallic filter medium, has one or more folded or curved sections to cover the opening of the housing, the flexible mesh or layer preferably having a corrugated profile. Supporting parts / elements, particularly on the side opposite the body, may be provided to maintain the corrugated profile.

[0010] According to one embodiment, the body has a central axis forming the longitudinal axis of the channel and is axially interposed between a structural frame and the obturation portion. The structural frame may define a support, separate from the body, for holding the metallic filter medium pinched or sandwiched between the structural frame and the body. In some embodiments, the structural frame includes a grid whose openings have, for example, a smallest dimension of at least 2 or 3 mm, for example, with openings reaching or exceeding 10 mm (or even 30 mm, at least for the largest dimension). The grid overlaps the metallic filter medium (for axial overlap).

[0011] The body is typically provided with a side wall and connects to the opening of the housing. Axial passages may be common / aligned in the assembly formed by the body, the filter element with the metallic filter media, and the grid section, which may extend under the metallic filter media (housing side). When a gas-permeable membrane is provided in the device, it may be supported (directly or indirectly) by the body, thus sealing the channel; the membrane may constitute a filtration element capable of retaining dust.

[0012] The body may be made of a rigid material, possibly plastic, which is devoid of radial or closing portions, except perhaps for thin partitions. More generally, the body has a side wall surrounding the gas flow area and is configured to connect, removably or permanently, to the housing at / on the housing opening. The body may optionally be designed as an annular projection of a housing component, or form an added connecting element.

[0013] The metallic filter medium may have one or more of the following characteristics: - the medium has pores of the medium whose size, for example a characteristic size, is less than or equal to 0.5 or 1 mm, preferably with pores of average diameter of submillimeter. - the filter medium comprises or consists of a metallic structure forming pores distributed in three dimensions. - the fabric or flexible layer comprises at least one layer of a non-woven, fibrous metallic material. - the filter medium comprises or is a non-woven material (for example based on a metallic material which is preferably homogeneous). - the filter medium comprises or is a felt, for example a sintered metallic fiber felt. - the filter medium comprises or consists of a metallic structure having a porosity greater than 70%, for example greater than 80 or 85%. - Metal fiber felt, for example stainless steel, may have a thickness greater than or equal to 0.6 mm, possibly at least equal to 3 or 4 mm. - A thermally insulating, gas-permeable material may be superimposed on the fabric or flexible layer of the metallic filter media, for example by being located between this fabric or layer and a face of the body where the channel inlet (gas exhaust channel) is located.

[0014] The filter medium can also be made of woven stainless steel, for example, with a thickness greater than or equal to 0.6 mm, possibly exceeding 2 or 3 mm. The filter medium can be attached to a grid belonging to a part that forms a frame surrounding four sides. Typically, more than 85 or 90% of one face of the filter medium is available (particularly for the impact of solid particles and for improving the permeability of the filter structure formed upstream of the channel inlet), whether or not a grid is present in a position underlying the metallic filter medium.

[0015] The channel can be subdivided into different ducts delimited at the level of the same opening in the housing, possibly with two or more membranes to distribute the edges for attaching these membranes. A structure with two parallel channels, each covered by a membrane (one sealing membrane per channel), can be used, under the same cover / hood. In all these cases, the device can provide a filtration element including the filter media, opposite / covering the inside of each duct of the channel.

[0016] According to one particular feature, the device may include a gas-permeable membrane, supported by the body and sealing the channel opposite the metallic filter medium. This membrane constitutes a filtration element. The membrane, if present, may be attached to the connection support formed by the body, typically from above, corresponding to a side opposite the metallic filter medium. The membrane can be kept separate from the metallic filter medium and / or the protective plate or grid by partitions provided in the channel. The membrane is flexible and has a fragile part so that it no longer obstructs the canal in a perforated or burst state of the membrane obtained in case of overpressure in the canal beyond an overpressure threshold.

[0017] A plastic part can form the hood (and thus the sealing portion). The body can be partially inserted into an internal volume of the hood delimited by the skirt, or alternatively surround a skirt of the hood. In some embodiments, the sealing part is part of a hood capable of being ejected or moved further away from the channel to free up a passage allowing the massive escape of a gas flow in the event of thermal runaway.

[0018] The body allows elastic interlocking of the hood, so that the body can axially retain the hood, for example by means of ridges or lugs formed on an external face of the body (annular body), by means of at least one internal ridge (for example when the body does not carry a membrane) and / or by means of tabs forming gripping edges or grooves for the engagement of ridges belonging to / carried by the skirt of the hood, in a configuration of protection of each membrane.

[0019] In embodiments of the device, the hood is molded in one piece of plastic material, preferably without elastically deformable / flexible part in the sealing part.

[0020] In embodiments, the metallic filter medium, which can define a lower face of the ventilation device, can be held upstream of the duct to form the impact zone for fuel particles and, more generally, for the largest solid particles (which may be incandescent) ejected from inside the housing and capable of igniting parts of a vehicle (even with a hood / lid still in place, if they were to rapidly degrade this hood and penetrate it, subsequently generating flames). The metallic filter medium forms a stable element that significantly disrupts / delays, or even stops, the dramatic chain of events leading to thermal runaway and subsequent fire propagation, as observed in cases where the hood is ejected or melts without any remaining fire protection.

[0021] The body can form a connection support for the hood and can integrate a rigid metal protective perforated plate, or metal grid plate (for example in stainless steel), this grid having openings of a size typically exceeding 5 or 6 mm (for example in width or diameter).

[0022] Typically, the connection support corresponds to a first pre-assembled part, including the body, the optional membrane, the metallic filter media and optionally the perforated plate or (metallic) grid underlying the body, while the cover corresponds to a second pre-assembled part. The second part mounts on the first part and remains attached to this first part, the fixation being permanent or resulting from a snap-fit ​​resistant to pressure variations in the channel, under the membrane.

[0023] The membrane can burst due to pressure buildup in the channel, which is not the case for the housing and the connection support (with the body) mounted on the housing, given that the gas flow can escape massively (at very high flow rates, for example) from the housing via the channel. The cover can remain in place, providing a large overall passage area, the passageways being able to include axial passage orifices offset from the channel and overlapping (opposite) an annular peripheral fixation zone or region. An annular peripheral fixing region can optionally be formed in the connection support by extending around a central axis of the body. This fixing region extends around the channel and is, for example, radially interposed between an annular seal providing a seal against the housing and a channel boundary wall that can be formed internally within the body.

[0024] In embodiment options, the body has a base wall or mounting flange and includes an annular channel boundary wall, which is a wall extending longitudinally from an underside of the base or mounting flange to an upper edge where a membrane can be placed (and typically fixed). The body and / or a rigid metallic protective plate may constitute a connecting part that carries an annular sealing element, preferably housed in an internal groove in the base wall or flange. The internal groove may open axially opposite the sealing portion (the sealing portion provided in the cover), in order to achieve an annular seal with the housing.

[0025] The body, for example provided with separating partitions, may optionally be made in one piece. The body has an upper / distal face of the seal, which may be a contact seal with the housing. In embodiments, the upper face has a substantially flat annular surface region to which a membrane is fixed or against which an edge of this membrane is pinched. The annular lateral wall of the body, serving to form the circumference of the channel, may extend longitudinally around a central axis between the flange that allows anchoring to the housing, typically having a substantially flat lower surface perpendicular to the central axis, and an annular edge axially distal to the opening of the housing. The annular edge may be formed in an axial projection that protrudes from an external annular shoulder of the flange.The flange consists, for example, of a rigid plastic piece forming part of the body, which can be placed axially between a metallic plate or grid arranged along it. The lower surface of the flange, and any membrane that is placed on the annular edge. It is understood that the metallic filter medium can be attached to the plate or grid that supports this medium and / or includes a portion that surrounds the periphery of this medium.

[0026] In embodiments allowing the metallic filter medium to be arranged parallel to a membrane, one or more of the following features are provided: - the ventilation device includes, opposite the canal, a piercing element, carried by one of the obturator part and the body, to perforate or burst the membrane in case of overpressure in the canal beyond an overpressure threshold. - the piercing member extends along an axial direction defined by a rod of the piercing member, such that a longitudinal axis of the rod passes inside a perimeter delimited by an external edge of the metallic medium. - the piercing element may be part of a group of piercing elements carried by the part of the hood. - one or more piercing elements may be included in the plastic part constituting the hood. - the piercing organ can be carried by a radial portion of the body positioned opposite the canal. - Screws or anchoring devices, made of metallic material, ensure the retention of the metallic filter media and possibly of the protective plate attached (or secured) to the filter media, by pressing the metallic media against the housing, for example in an area surrounded by the seal of the ventilation device. With these provisions, it is possible to achieve a compact arrangement, at the level of a housing opening, with a membrane protected from dirt by a hood for management of the usual ventilation mode, while having a safety in an emergency mode with massive gaseous exhaust, by ensuring that the membrane is pierced and that the plastic parts of which the hood is made are not melted, which prevents or delays the creation of flames.

[0027] The device, equipped with at least one membrane, allows both pressure equalization of a battery case and emergency ventilation, typically by protecting the gas-porous membrane during its equalization function. A pre-assembled design, without movement of the locked cover, allows the device to effectively seal the opening of the case (and maintain the integrity of each membrane) in an environment subject to vibrations. This is particularly relevant when the battery case is mounted in a motor vehicle, for example, a car or other rolling machine. In some embodiments, the membrane (at least one membrane) is designed to ensure oil, water, and dust tightness. It may be made of hydrophobic material and / or form a water barrier.

[0028] According to one aspect, a method for assembling a ventilation device is proposed which has a fire barrier effect while minimizing the risks of creating a blockage in the area through which a gas flow must escape urgently (risk of falling molten plastic material constituting the sealing portion for example).

[0029] To this end, a method is proposed for assembling a ventilation device for a battery case, using a metallic filter medium suitable for mounting under a body intended to equip the battery case, the body defining a channel forming an outlet through an opening in said case, the method comprising the steps essentially consisting of: - provide the metallic filter media; as well as a support frame or side-walled element designed to surround the metallic filter media; - secure the metallic filter media to the body, by fixing the filter media in an arrangement underlying the body opposite an outlet of the channel allowing the evacuation of gas from the housing; in which the bonding of the filtering medium allows a flow of gas entering the channel to be filtered by a flexible cloth or layer of gas-permeable metallic wires or fibers which constitutes or is part of the metallic filtering medium, by which means the flexible cloth or layer constitutes, in said device, a fire-resistant protection between the housing and the body channel with a barrier effect to solid particles so as to allow only a purified fluid flow without solid particles to pass into the channel.

[0030] The metallic filter medium may be integrated as close as possible to the opening of the housing, for example, with one face of this medium defining an external face of the device, suitable for positioning opposite the inside of the housing. Where applicable, this face of the medium overlaps with a support grid belonging to the support frame.

[0031] In this method, a membrane can be fixed to the body, this membrane being permeable to gases to allow selective filtration of a gas flow circulating in the channel to leave the battery housing. The process uses, for example, the body, made from a single piece of plastic, to: - to form a first support surface for fixing the membrane; and - to form a second support face to connect, directly or indirectly, the metallic filter media to the rest of the ventilation system. It is understood that the first support face and the second support face can be opposite each other in the ventilation device.

[0032] A hood with a sealing portion may be provided in the device, opposite the metallic filter media. For emergency ventilation, passageways are provided in the hood and / or are present to bypass the sealing portion. Typically, these passageways may be distributed throughout the hood.

[0033] In embodiments of the assembly process, one or more of the following arrangements may be adopted: - the metallic filter media is supplied in the form of a sheet, cloth or flexible layer, the underside / facing the housing (housing opening) of which is made of stainless steel or similar metal. - the metallic filter medium includes a portion or zone of thermal protection opposite a channel inlet, being wider than the inlet or with at least one of a matching shape and a matching in perimeter / border dimensions, between the contour / border of the outlet and the contour of the thermal protection zone.

[0034] The membrane can be fixed by a hot welding step, for example by using vibratory energy, optionally so as to melt one or more annular reliefs formed on the body. An annular portion with such reliefs can thus be melted during the welding step. If necessary, the welding can be carried out ultrasonically, for example with a raised bead on the plastic part and a flat sonotrode, or on a flat plastic surface and a raised bead on the sonotrode. The membrane can be fixed in an annular weld zone and deformable in the sealing portion (permeable to gas) surrounded by this weld zone.

[0035] According to one particular feature, the hood has a skirt or tubular portion adapted to internally house (thus surrounding) a projection or insertion portion belonging to the body. The body may, for example, have a hollow, annular, or annular-sided projection. A mounting / connection support may be formed by the body, which is, for example, made in one piece and optionally designed to axially cover a protective metal grille. The body is secured to the housing by fasteners (bolts, screws, or other suitable components for a rigid connection), for example, by positioning all or some of the fasteners in an area enclosed by a gasket on the housing. Where holes are provided in the cover, at least one or more of the fasteners are positioned directly above a corresponding hole in the cover. The fasteners are metallic and retain a protective plate or frame, which typically surrounds the filter media. Optionally, the device forms a pre-assembled ventilation unit that does not yet cover the battery case opening. This results in a device that forms a pre-assembled functional component, which can be mounted by screwing, quarter-turning, or other simple assembly methods onto the area of ​​the case that forms the opening (a wide opening compared to the narrow openings sealed by flaps). Such a simple mounting method can achieve a seal using a gasket applied to the base of the device, while the cover or similar protective part remains in its non-sealing configuration, fully fitted onto the body that serves as a connection support. The device can therefore be transported, packaged, and delivered robustly, with a cover, and minimizes the number of steps required to install the device on the battery case.The hood / cover can be notched or provided with axial openings for the installation of fastening elements for connection to the housing while the hood is already attached to the body. Brief description of the drawings

[0036] Other features, details and advantages will become apparent from reading the detailed description below, and from analyzing the attached drawings, in which: [Fig.1] is an exploded perspective view of a ventilation unit suitable for mounting directly on a wall of a battery case, in order to close an opening in that wall. [Fig.2] illustrates, by perspective, half of a ventilation device having an assembly similar to that of the unit in [Fig.1] using a membrane and a metallic filter medium closing, on either side, a degassing channel. [Fig.3] is a bottom view of a ventilation device, showing the position, underlying the gas exhaust channel and surrounded by a seal, of the metallic filter medium which provides a fire barrier effect. [Fig.4] is a longitudinal section view of a ventilation device, following an option with a body screwed onto the casing by screws engaging with a structural element with a filtering part including a metallic medium. Figure 5 shows an example of mounting the ventilation unit on an external face of a battery case wall. Figure 6 shows, by a cross-sectional view, a detail of a variant using a corrugated metallic medium mounted between two support parts. Description of the implementation methods

[0037] Several non-limiting examples of embodiments are set out in detail below. In the various figures, identical reference numerals indicate identical or similar elements.

[0038] With reference to Figures 1, 2, 4, and 5, a ventilation / pressure compensation unit is shown that can be supplied as a pre-assembled unit, ready to seal an opening O in a battery case by typically mounting on the side of an external face of a shell or plate of the case P. In what follows, this unit (possibly pre-assembled) is referred to as the ventilation device 1. In preferred options, the device 1 has a mounting portion (forming a hood / cover support) including or consisting of a body 2 for connection to the case, and is provided with fastening means PF2, for example, formed as an annular flange or as insertion / retaining tabs for holding it in position on the battery case. The fastening means PF2 may be provided in a base of the body 2, which covers the case P or is optionally insertable (partially) inside the battery case.The element or body 2 may essentially consist of a rigid connector made of plastic material, optionally provided with a J-joint mounted or attached to this connector. The body 2 may optionally have a flattened configuration, with a thickness (corresponding to a height) that is, for example, at least four or five times less than an external width or diameter. The body 2 may be made of a single piece of plastic material, unreinforced or reinforced (for example, with glass fibers, carbon fibers, or similar) or a similar molded material.

[0039] The body 2, which is hollow and open at two opposing axial ends, may have a flexible, porous / gas-permeable membrane 5, which provides a pressure compensation effect. The membrane 5 extends transversely with respect to a longitudinal axis, typically a central axis X of the body 2. The membrane 5 can inflate outwards in the event of slight pressure relief and can even be punctured if the overpressure poses a risk by exceeding a certain overpressure threshold. In embodiments, such as in [Fig. 2], for example, the membrane 5 is not exposed / visible from the outside, thanks to a cover 3 of the device 1 which is mounted on the body by clips or any suitable fastening method that allows the cover 3 to be rigidly fixed.

[0040] Figures 2 and 4 show a hood assembly 3 in which a single flat, fire-resistant filter element, including the metallic filter media 8 (formed, for example, as a single block), is arranged opposite the interior of the channel C2 for a complete separation effect of solid particles, even under heat conditions with a gas flow exceeding 500 or 600°C, which is compatible with: - Normal ventilation in both directions DI (incoming) and outgoing (D2) along the central axis X, with the media 8 underlying the body 2, - and emergency ventilation in the D2 direction, after release of the exhaust end of the body 2 due to the degradation / bursting of the membrane 5, which proves effective without degradation of the fire barrier effect (impact of particles) combustibles on a protection zone corresponding to an inner face F8 turned / oriented opposite to channel C2, therefore without impact on body 2 which is made of plastic).

[0041] The cover 3 has a sealing portion 9, which may be visible from the outside, formed from a polymer part resulting from a molding (based on a thermoplastic material) or a suitable plastic material. The sealing portion 9, which is not perforated, may be smaller than the passage cross-section formed by the channel C2.

[0042] As can be clearly seen in particular in Figures 1, 2 and 4, the body 2 may have a side wall 20, a lower end forming an open base, such that the body 2 delimits a channel C2 which opens through an upper end of the body 2, which is an outlet end, which can be closed by a membrane 5. Here the terms "lower" and "upper" do not prejudge the final assembled arrangement of the ventilation device but facilitate the explanation made with reference to some of the figures. The channel C2 extends longitudinally between the base end and the outlet end, typically around a central axis X of the body 2 which is an axis that can pass through the opening O in the assembled state of the ventilation device 1, as illustrated for example in [Fig. 5]. The side wall 20 can be an external side wall of the body 2 which optionally includes a conduit or conduit element 200, as seen in [Fig.2].

[0043] A lower groove G2 ([Fig. 1]) provided in the body 2 allows the seal J or sealing element, for example in the form of a ring, to be housed radially away from the conduit element delimiting the path or channel C2 for gas circulation. More generally, the side wall 20 can carry a seal J by positioning it away from the conduit / channel element C2. The seal J can thus be spaced / away from a very hot gas discharge zone in situations of overheating or thermal runaway.

[0044] Channel C2 is offset and internally spaced relative to the RF mounting area for attaching the cover 3 and for airtight attachment to the housing P. When a membrane 5 is provided, it is part of a pre-assembled unit. This unit may consist of the perforated plate 4, the filter portion including / constituted by the metallic filter media 8, and the connection support SC and the membrane 5. An annular portion 5c of the membrane 5 may be airtightly attached to one end of the conduit element formed by the body 2. Of course, the membrane 5 may also be attached to an annular portion 5c on another surface of the body or by pinching it into the pre-assembled unit, in alternative embodiments. An intermediate support may also be added to provide a membrane support.

[0045] In Figures 1, 2 and 4, it can be seen that the body 2 may have an annular radial portion which includes or forms the bottom of the groove G2 oriented towards the housing P in allowing the annular J-seal to be received. The J-seal may (before axial compression achieved by anchoring / fixing) typically have a height greater than the depth of the G2 groove, or at least be sized to extend axially beyond this G2 groove. More generally, the J-seal may protrude downwards (here towards the housing), thus presenting a surface that extends beyond the G2 groove and is capable of bearing axially against the battery housing. The annular faces defining the G groove may each have protruding ribs or ridges to retain the annular J-seal. These ridges or ridges, spaced along the circumferential direction, project radially towards the inside of the G2 groove.

[0046] The body 2 may have a projection 25 or 2d, projecting axially from the annular radial portion that forms the RF attachment region. As shown in particular in [Fig. 2] and 4, this projection 25, 2d (tubular, rectangular, or cylindrical) may extend axially from the base of the body 2 so that the conduit element extends from the base to an edge formed by the projection 25, 2d. Thus, an inner face of the conduit element 200 can be formed with an axial extension greater than the axial extension of the base or the annular RF attachment region. More generally, the device 1 typically forms at least one channel C2, preferably delimited by a circumference of the conduit element 200 which may protrude on one evacuation side from the rest of the body 2. The channel C2 can serve both for an air supply and for an air evacuation, when the evacuation end of the body 2 is closed by a permeable membrane 5.. In some variants, for example using at least one non-return valve, it may be provided that the C2 channel is used solely for air evacuation.

[0047] The channel C2 of the body can take various forms, in some cases allowing for the formation of different discharge paths downstream of the opening O. In the illustrated cases, the channel C2 is delimited by the conduit element 200 and / or a portion of the body 2, in order to guide a gaseous flow FG escaping from the casing P through the opening O (the flow exiting through the opening passing entirely through the channel C2). In the non-limiting case of Figures 1 and 2, a channel C2 is shown subdivided into sub-channels SC2 due to the presence of separating spacers or partitions 22 that can divide the channel into a grid and allow for the distribution of the gaseous flow FG.The configuration with spacers or crossbeams / partitions, distributed at several levels or extended along the direction of the central axis X, can limit the propagation and extent of flames that could form with the sudden evacuation of combustible particles near the opening O of the casing (where oxygen is present in abundance), in case of overpressure with thermal runaway in the casing P. . Example of the production of a flexible material made of metallic fibers

[0048] The filter medium 8, 108 can advantageously combine thermal resistance and high porosity, for example, greater than 80 or 85%. The metallic wires or fibers are, for example, woven (with a very fine mesh), possibly having several superimposed layers of parallel metallic fibers. Alternatively, the wires or fibers are gathered into a nonwoven layer. In some variations, sintered fiber can be used. By way of non-limiting example, the filter medium 8, 108 contains or is made of very fine metallic filaments (1.5 to 80 µm) laid uniformly to form a three-dimensional nonwoven structure sintered at the contact points. The filter medium 8, 108 can be part of a pre-assembled filter component or element.

[0049] In certain options, a multilayer construction may be provided, with each layer composed of fibers of potentially different diameters to achieve optimal performance, for example, pressure drop, filtration efficiency, particle load-bearing capacity, and support strength. In this case, the multilayer material may have a graduated design, so that the solid particle retention capacity is much higher and, consequently, the service life is longer. More broadly, whatever structure is chosen to form the porosity or interstices in the layer of metallic fibers or filaments (a porosity greater than 70%, for example reaching or exceeding 80%, is preferred), the arrangement of these fibers or filaments is chosen to allow the passage of gas at high flow rates, while intercepting solid particles.

[0050] The medium 8, 108 can optionally be obtained from several layers of fibers / filaments deposited one on top of the other, or from a strip or web of metallic fibers that is folded. A mechanical treatment can be performed to adjust the density. For example, in one application, the strip or web is twisted and / or folded to obtain a gap / space of approximately 10% between adjacent layers. Stitching, the use of a needle loom, or any suitable device for the mechanical support of the flexible ML layer can be used.

[0051] Regardless of the manufacturing process adopted, the metallic fabric or layer ML can constitute a flexible part, formed into a homogeneous, gas-permeable piece which is: - retention between the body 2 and the housing P, typically using a perforated plate 4 forming a support frame 4, - or alternatively integrated into a heterogeneous component which includes a frame or peripheral fixing parts and the ML metallic fabric or layer constituting all or part of the metallic filter medium 8, 108. If necessary, the metallic filter medium 8, 108 can be 4 made in the form of a flexible cloth or layer of felt directly glued to a support, possibly extending further outwards, relative to the opening O, than this support. In practice, bonding can be carried out around the periphery of a gas passage region. Bonding can optionally be combined with axial retention using tabs or fasteners 4r. [Fig. 3] shows the case, by no means limiting, of fasteners 4r extending radially inwards from the edge of a frame or support plate 4, allowing the metallic filter media 8 to be held in place. The plate 4 also has external radial tabs for connection to the body 2 (for example, for fixing via screws V). In this case, the impact face F8 (for solid particles exiting the housing) of the metallic filter media is exposed / not covered from below, except for thin or short support portions (see tabs / fasteners 4r in the case of [Fig. 3]). Typically, more than 85 or 90% of the F8 face is available, whether or not a G4 grid is present in a position underlying the 8,108 media.

[0052] In the non-limiting case of [Fig. 1], the metallic filter media 8 is fixed and held in place by a form cooperation between the grid portion G4 of a perforated plate 4 and the perimeter of the media 8, for example delimited by two parallel long sides 8a, one end 8b possibly straight and the other end 8c possibly straight. A rectangular format of the media 8 may be provided.

[0053] More generally, it is understood that the metallic filter media 8, 108 can form a sealing wall not penetrated by fastening elements. A frame and / or fastening elements serve to prevent / prevent movement of the media 8, 108. In the example of [Fig. 1], the plate 4 is intended to be highly perforated in a central portion covered by the metallic filter media 8, while also having a margin portion that includes fastening elements. Here, the plate 4 has, for example, fastening tabs 4p or other mounting elements that can be aligned with the fastening means PF2 formed in the body 2.When screws V or similar anchoring elements are provided to pass through this plate 4 and an annular RF flange or fixing region of the body 2, split rings or metallic elements which constitute compression limiters 12 may optionally be used in mounting holes / conduits which may constitute the fixing means PF2, in order to form a contact interface with the plastic surfaces constituted for example by the housing (wall P) and the body 2.

[0054] The protective grid or plate 4 is, for example, formed from a single piece, with a flat / planar shape (therefore thinner than the body 2). The combination of this plate 4 and the metallic filter medium 8 makes it possible to create a fire barrier (limiting and even inhibiting flames by preventing the propagation of particles). combustibles and flames through the opening O). Tabs or fastening elements 4f (visible in [Fig. 1]) are, for example, formed in the peripheral edge of the protective plate 4, in order to hold it against the base end of the body 2, cooperating with additional fastening elements provided in the RF fastening area, for example in the form of clips projecting axially from an underside face of the body opposite the housing P in the mounted state. More broadly, it is understood that the protective plate 4 can be a part that is fixed to the body 2, directly covering the channel C2 on the side opposite the cover 3.

[0055] The peripheral edge of the protective plate 4 is surmounted by the RF fixing region provided in an annular flange of the body 2, which extends around the guide element 200. The edge of the grid portion G4 can follow the edge of the channel inlet C2, axially overlapping this edge (thus covering the entire perimeter of the channel inlet C2). The edge of the plate 4 can be a continuous edge, rectangular or ring-shaped, for example. The case with a protective grid or plate 4, for example made of metallic material, interposed between the housing P and the body 2 (provided to be made of plastic or similar molded material), is only one option to allow the metallic filter media 8 to be guided and held.

[0056] The assembled ventilation device 1 is fitted with its seal J, in order to close the opening O while ensuring that gas exchange is carried out with filtration by the metallic filter medium 8, 108 and then possibly by an appropriate number of membranes. In the non-limiting example of Figures 1-2 and 5, it is understood that the seal J can bear against an annular seating area provided on the housing, around the opening O, typically without penetrating internally into the housing. This seal J can be an annular seal, for example made of elastomeric material, coming into axial contact with the housing P, on an external face of the latter. Attaching the cover to the body

[0057] The attachment of the cover 3 to the body 2 (which includes the attachment means FMI, FMI') can be achieved by plastic deformation of the additional attachment means FM2, FM2', or FM provided in the cover 3, typically made from a single piece of plastic material. Axially projecting tabs FM2, FM can form at least part of the additional attachment means / elements. More generally, an elastic fit can be provided with the use of axial stops, possibly allowing for an anti-retraction effect of the cover.

[0058] In the non-limiting case of [Fig. 1], the additional fastening means FM2, FM2' or FM, by an elastic return effect to their initial shape, prevent the removal of the cover 3, so that the latter remains fixed to the body 2, regardless of the temperature rise in the channel C2. This means that, if the filter medium 8, 108 were not present, the cover 3 would not detach but would risk being broken. and melted near its sealing portion 9, with the risk of blocking escape routes, before the fixing area (further from channel C2) is itself degraded / broken if the thermal runaway persists. The configuration provided here, with multiple passages 03, 03' and the shield corresponding to the media, promotes massive gaseous escape without pressure drop, and with exhausts via the hood 3 (or around the hood 3) which facilitate cooling and minimize the risk of deformation / damage due to heat. This effectively prevents a state of overpressure from persisting with the associated overheating. In some options, the hood 3 can be ejected or offset from the body 2.

[0059] The cover 3 can be fixed relative to the body 2, in the absence of an axial spring or any part allowing a degree of freedom in translation or rotation. In the illustrated options, an anti-rotation effect is also provided by the action of the clip lugs FMI, FMI', typically engaged through windows or recesses in the cover 3. More generally, the cover 3, which forms the sealing part 9, can be directly engaged with raised features of the body 2, which in practice prevents accidental removal of the cover 3, for example, in the event of a jolt when the housing P is mounted in a motor vehicle. More broadly, it is understood that the formation of a fire barrier, by the metallic filtering medium 8, along an end of the body which is not in contact with the hood 3 and which is axially opposite to the hood 3, allows great flexibility in the design and assembly of such a hood / cover. Example of a drilling function integrated into the lid

[0060] With reference to Figures 1 and 2, the cover 3 is provided with one or more piercing elements 6, 6', oriented towards one or more areas of the membrane 5, each of which is located away from the annular fixation portion 5c. In the non-limiting case of [Fig. 1], the cover 3 includes, opposite the channel C2, at least one first central piercing element 6. In addition, the obturation portion 9 may incorporate one or at least two piercing elements 6' offset along the elongation direction of the cover 3, the latter generally having a rectangular or non-circular shape. Each piercing organ 6, 6' is rigid and provided with a point or end adapted to tear / pierce the membrane 5 opposite, which swells in protrusion above the evacuation end of the body 2.

[0061] Whether the piercing member 6, 6' is made in the form of a protruding relief of the part of the hood 9 or designed as any pointed or cutting structure carried by the cover 3, it is understood that this piercing member 6, 6' makes it possible to pierce or burst the membrane 5 in the event of overpressure in the channel C2, typically beyond an overpressure threshold for which thermal runaway is very probable or proven. One or more piercing organs may extend parallel to each other, each being included in the same plastic piece constituting a rigid component of the cover 3.

[0062] In the hood 3, passageways 03, 03' can be distributed in areas of the hood 3, around the piercing member 6, 6', to facilitate the exhaust of gas while maintaining the initial configuration (and typically the initial integrity) of the device 1. Body 2 can provide unidirectional guidance of the gas flow FG exiting through opening O, with partitions 22 optionally contributing to a linear guidance effect. Flow deflection can be achieved via cover 3, and passages 03' can open laterally to the outside through the periphery of cover 3. Option(s) with corrugated metal media

[0063] The metallic filter medium 108, as in the case of [Fig. 6] for example, can include a flexible corrugated layer ML while fitting along the opening O, under the body 2, to form a barrier effect against solid particles upstream of the channel C2 in the direction of gas discharge. The two opposite faces F8, F8' of the fabric or flexible layer ML can be parallel, following the same corrugated profile. A continuous corrugated wall P8, to avoid interruptions in the ML layer, is thus formed, enabling a fire-barrier effect. The design using flexible yarns or fibers can achieve such a corrugated profile. Support or reinforcement can be provided locally, for example with contacts C4 or bonds at the folds, to make this conformation stable, possibly rigid at least locally.The perimeter of the metallic filter media 108 can be defined at an edge, possibly rectangular, which is received or held in a rigid frame.

[0064] When a corrugated profile is provided for the metallic medium 108, the flexible layer ML can be connected to one or two support parts 4a, 4b, typically rigid, which are for example made integral with the body 2, by being able to be fixed to an external frame serving to define an edge B4 in an equivalent way to the case with a flat grid or perforated support plate 4. At least the support 4a located on the opposite side can be metallic, possibly similar to a perforated plate 4 (possibly fixed as in the case of [Fig.4]), but with parallel bars b, b' of two kinds arranged alternately to make the contacts C4 or connections from below the layer ML, at the level of the fold lines (the bars b being supported on the straight bottom areas LP1 in the face F8). The faces F8, F8', provided with lines LP1, LP1' or straight bottom zones in the corrugated profile, are, for example, supported in a predefined conformation (here with said corrugated profile) by the support part(s) 4a, 4b, each including A plurality of support elements are attached to the flexible layer ML along the lines LP1 and / or LP1', which correspond to straight bottom zones. The outward edges or lines LP2 may also be in contact with bars b' of a corresponding support section 4a, 4b.

[0065] In the support structure, spaced and parallel bars b, b', preferably rigid, may be provided, forming at least the support members in the support part 4a, 4b. These structural elements make it possible to maintain and structure the corrugated profile conformation of the fabric or layer ML. The bars b, b' may be selectively connected to the respective faces F8, F8', each by a lateral face of the bar, preferably along a fold line made in a constituent material of the layer or fabric. In other words, the support can be externalized with respect to the ML layer. For example, as seen in [Fig. 6], the faces F8, F8' are each associated with a bar structure forming a respective support part 4a, 4b, so that it is provided in each bar structure: - a first type of bars, in which each bar b is joined and linked to a line LP1, LP1' of the bottom of the corresponding outer face (F8 or F8'); and - a second type of bars, for which each bar b' is attached and linked to a line LP2 projecting from the corresponding outer face (F8 or F8').

[0066] With reference to [Fig. 6], the support members may consist of bars b, b' which preferably have the same length to define an identical length of attachment on the flexible layer ML to which they are attached. As in some cases without corrugations, the metal fibers or wires of the flexible layer ML may be distributed in three dimensions between the two faces F8 and F8', for example, forming a nonwoven fabric. Alternatively, a woven fabric or layer may be prepared with one or two support parts allowing the maintenance of a corrugated conformation, to obtain the corrugated wall P8. Assembly examples

[0067] The body 2 can directly support all the other elements of the device 1, namely the seal J, the protective plate 4 (or similar perforated / grid part G4) which can be elastically fitted or rigidly fixed under the body 2 against its base, the metallic filter media 8 and the cover 3 which has the sealing portion 9. The optional membrane 5 can be welded or attached with a sealing ring contact, the perforated protective part, typically in the form of a cover 3, surrounding the opening O of the wall of the battery case P.

[0068] The screws V or fastening elements allow the body 2 to be mounted in or around the opening O, against the housing P, by defining the channel C2, formed vertically above the opening O or more generally by following the longitudinal direction of the body 2 (along the central axis). In the assembled state, the hood 3 is kept spaced from the wall P by the base of the body 2. The metallic filter media 8, 108 may be supplied in a filter component or element which includes a metallic support frame enabling the formation of a typically non-permeable periphery around the metallic filter media 8, 108. The support frame may form a side wall surrounding the metallic filter media 8, 108, without any gap allowing gas to pass between this frame and an edge or outer periphery of the media 8, 108.

[0069] Whether mounted on such a frame, plate 4 or similar support element, or not, the metallic filter media 8, 108 is made integral with the body 2, by fixing this metallic filter media 8, 108 in an arrangement underlying the body 2 opposite the outlet of the channel allowing the evacuation of gas from the housing, and therefore opposite the hood 3.

[0070] As clearly visible in Figures 1 and 6A, a shoulder can be provided in the body 2, at the RF attachment area, to allow clips to be made both on the base (FMI' attachment means) and on the periphery of the base of the body 2 (with the FMI attachment means each protruding laterally on one side of the body 2). This allows the cover 3 to be fixed in an area radially offset outwards, relative to the metallic filter medium and possibly relative to a weld area of ​​the membrane 5.

[0071] The ventilation device 1 can form a compact, responsive arrangement within the housing P, minimizing pressure drop. This can advantageously prevent harmful damage and fire propagation, while ensuring that the device's plastic components are protected from incandescent particles and flames. Thus, a return to equilibrium with cooling can be achieved without external damage to the housing and before plastic can flow and block channel C2 or a grid G4 interposed between the housing and the channel.

[0072] In the embodiment illustrated in [Fig.4], it can be seen that the anchoring by the V screws, also metallic, makes it possible to ensure a flat arrangement of the filter component including the metallic filter media 8. In this type of case, it is also possible to make a flat component whose frame can form the plate 4, through which the V screws are fixed, while the metallic filter media 8 forms a high permeability fire barrier which is bonded (for example by sintering) to the frame of the plate 4.

[0073] This disclosure is not limited to the embodiments described above, only by way of example, but encompasses all the variants that a person skilled in the art may consider within the framework of the protection sought.

[0074] For example, when a membrane 5 is provided, there are different ways of freeing the channel C2 to allow the circulation of a higher gas flow rate. The membrane 5 may thus, in variants, have a retractable structure or have at least one fragile region facilitating its rupture, for example without the use of a perforation point, provided that the level of deformation required for such rupture is reached only in the event of exceeding an overpressure threshold (on the channel side / inside the battery housing).

[0075] Furthermore, the ventilation unit or device 1 may include a membrane support 6, which may be formed separately from the body 2. This design can simplify the production of the device 1, since the membrane 5 is not welded directly onto the body 2, but onto another component of the membrane support (designed separately). The welding process on the membrane support can be less expensive and faster, without the complexity of the welding tool, for example. This may also allow for a more compact body 2.

[0076] Finally, the term battery case should be understood in a general sense, the case being able to contain one or more groups of accumulators capable of supplying energy in electrical form or energy usable in any form for conversion into electrical energy.

[0077] The wall of the housing P including the opening O can have any orientation. Although the non-limiting example of [Fig.5] corresponds to an orientation of this plate / wall in a generally horizontal plane to have a cover 3 or protective part axially surmounting (from above) the body 2 allowing the connection of the cover 3, so that the axis X is vertical here, other arrangements are permitted, in particular with a ventilation unit mounted laterally on the battery housing.

Claims

Demands

1. A ventilation device (1) for a battery case, in particular for a case comprising one or more batteries, the device (1) comprising: - a body (2) having a side wall and connecting to an opening (0) of the case; - a channel (C2), provided in the body (2) to guide a gas flow (FG) escaping from the case through the opening (0) along a longitudinal axis (X) of the channel (C2); - a sealing part (9), attached to the body (2), preferably in the form of a hood (3) which is perforated by covering the channel (C2) on a side opposite the opening (0); characterized in that the ventilation device (1) comprises a metallic filter medium (8; 108) for fire protection carried by or covering the body (2) in an arrangement underlying the body (2) opposite the sealing part (9), the metallic filter medium (8;108) including a flexible fabric or layer (ML) of gas-permeable metallic yarns or fibers that seals the channel (C2) from below, thereby causing the metallic filter medium (8; 108) to form a barrier to solid particles, allowing only a purified fluid flow without solid particles to pass into the channel (C2).

2. Device according to claim 1, wherein the metallic filter medium (8; 108) is composed of at least 95% by mass of metal wires and / or fibers, the metal preferably being steel.

3. Device according to claim 1 or 2, wherein the body (2) has a central axis forming the longitudinal axis of the channel (C2) and is axially interposed between a structural frame (4) and the obturation part (9), the structural frame (4) defining a support, distinct from the body (2), for holding the metallic filter media (8; 108) pinched or sandwiched between the structural frame (4) and the body (2).

4. Device according to claim 3, wherein the structural frame (4) includes a grid (G4; 4a, 4b) whose openings have a smallest dimension of at least 2 or 3 mm, the grid (G4; 4a, 4b) being in overlap with the metallic filter medium (8; 108).

5. A device according to any one of the preceding claims, further comprising a gas-permeable membrane (5) carried by the body (2) and blocking the channel (C2) opposite the filter medium metallic (8; 108), the membrane (5) constituting a part of filtration, the membrane (5) being flexible and having a fragile part so as not to obstruct the channel (C2) in a perforated or burst state of the membrane (5) obtained in case of overpressure in the channel (C2) beyond an overpressure threshold.

6. Device according to claim 5, comprising opposite the channel (C2) a piercing member (6, 6'), carried by one of the obturation part (9) and the body (2), for perforating or bursting the membrane (5) in case of overpressure in the channel (C2) beyond an overpressure threshold.

7. Device according to any one of the preceding claims, wherein the sealing part (9) is part of a hood (3) capable of being ejected or moved further away from the channel (C2) to free up a passage allowing the massive escape of a gas flow (FG) in the event of thermal runaway.

8. Device according to any one of the preceding claims, wherein the flexible fabric or layer (ML) comprises at least one layer of a non-woven, fibrous metallic material.

9. Device according to any one of the preceding claims, wherein the fabric or flexible layer (ML) has one or more folded or curved parts to cover the opening (0), the fabric or flexible layer (ML) preferably having a corrugated profile.

10. Method of assembling a battery case ventilation device (1), using a metallic filter medium (8; 108) suitable for mounting under a body (2) intended to equip the battery case, the body (2) defining a channel (C2) forming an outlet through an opening (0) of said case, the method comprising the following steps: - providing the metallic filter medium (8; 108) and a support frame (4; 104) or sidewall element intended to surround the metallic filter medium; - securing the metallic filter medium (8; 108) to the body (2), by fixing the metallic filter medium (8; 108) in an arrangement underlying the body (2) opposite an outlet of the channel (C2) allowing the evacuation of gas from the case; in which the bonding of the filter medium (8; 108) allows the filtering of a gas flow entering the channel (C2), by a flexible fabric or layer (ML) of permeable metallic threads or fibers to gas which constitutes or is part of the metallic filter medium (8; 108), by which means the fabric or flexible layer (ML) constitutes, in said device (1), a fire barrier between the housing and the channel (C2) of the body (2) with a barrier effect to solid particles so as to allow only a purified fluid flow without solid particles to pass into the channel (C2).

11. Assembly method according to claim 10, wherein a membrane (5) is fixed to the body (2), the membrane (5) being gas-permeable to allow selective filtration of a gas flow circulating in the channel (C2) to leave the battery housing, the method using the body (2), made of a single piece of plastic, to: - form a first support face for fixing the membrane (5); and - form a second support face for connecting, directly or indirectly, the metallic filter media (8; 108) to the rest of the ventilation device (1); wherein the first support face and the second support face are opposite each other.

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