VENTILATION DEVICE WITH PROTECTIVE SCREEN FOR BATTERY BOX(ES), AND ASSEMBLY METHOD

Abstract

The ventilation device (1) for a battery case includes a mounting body (2) forming or associated with an opening edge of the case, a channel (C2) in the body, a gas-permeable membrane (5) carried by this body while closing the channel, and a cover secured to a peripheral support of the body. The channel, surrounded by this support, guides a gas escape coming from the inside of the case. The cover (3) may have, opposite the channel, a piercing member (6) for perforating or bursting the membrane in the event of overpressure in the channel. Orifices (O3), provided for example in the cover, allow an accelerated emergency escape of gas coming from the channel when the membrane is perforated or burst. A screen (8) with a metal layer, secured to a plastic part (9) of the cover, forms a heat shield zone (ZP8) offset from the or more orifices (O3). Abstract figure: Figure 1

Description

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

[0001] The present disclosure relates to the field of battery systems, in particular ventilation equipment allowing pressure compensation for a battery. The invention relates more particularly to a device, mounted on the housing of a battery / power supply, which includes at least one permeable pressure compensation membrane and a perforated plastic cover protected by a metal screen and a method of assembling such a device. Technological background

[0002] Document US 2013 / 032219 A1 discloses a pressure compensation device, which includes a porous membrane to allow the gases enclosed in an electrochemical module to pass through. The membrane protects the interior of the module by preventing the penetration of dust or water. In the event of instability (internal pressure too high), the membrane rises to such a level that the cover of the compensation device pierces the membrane, which allows the gas to escape with a more significant flow rate. For this, the cover which covers the membrane has numerous openings for the escape of air at a significant flow rate, for example by defining an overall passage section of the same order of magnitude as, and possibly even greater than, the passage section of the circulation channel closed by the membrane.

[0003] Such devices are designed from plastic materials, for example plastic materials that are very unlikely or not likely to produce flames or smoke when they melt. Some assemblies provide for ejection of the cover. In this case, the following problems are encountered: - if the ejection does not occur or is limited due to an obstruction on the side of the cover (for example, a part deformed by an impact prevents the cover from moving apart), the gas accumulates; there is a plug effect, since the cover does not have a massive exhaust opening, and the risk of explosion becomes significant. - conversely, if the ejection occurs correctly, the probability of diffusion of incandescent particles and associated flames becomes high, with a high risk of rapid propagation of fire (contact with the vehicle chassis).

[0004] Other assemblies, for example using a clip-on fitting, do not allow ejection of the cover. In this case, it has been found 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 ventilation devices in battery cases melt quickly, which can cause detachments or disintegration of the parts which will block all or part of the degassing channel (very rapid and significant blockage when a grid is provided under the cover). The gas accumulates; there is a plug effect, and the risk of explosion becomes significant.

[0005] There is therefore a need for devices of simple design, durable and usable efficiently for the pressure compensation of batteries. Abstract

[0006] The present disclosure improves the situation.

[0007] For this purpose, a ventilation device is proposed for a battery housing, in particular for a housing comprising one or more batteries, the device comprising: - a body, for example forming a connector; - a channel, delimited by a conduit element and / or a part of the body, to guide a gas flow escaping from the housing an opening (housing opening where the body is connected); - a gas-permeable membrane, carried (directly or indirectly) by the body, closing the channel, the membrane being able to constitute a filtration part capable of retaining dust and / or water; - a cover, comprising a perforated plastic cover part secured to a peripheral connection support belonging to the body, covering the membrane; - a metal layer screen which is separate from the membrane and included in or secured to the cover, forming, in a protective zone provided in the screen, a heat shield interposed between the channel and a closure portion (of the cover / belonging to the cover) which is opposite the channel (this is for example a closure portion which belongs to the cover part), - passageways which allow bypassing the protective zone which corresponds to an overlapping zone between the screen and the obturation portion.

[0008] The planned passageways can be arranged: - in the cover, in the hood part and offset from the protective area, so that the cover is perforated; - and / or laterally between the cover and the body. The passageways can allow, when the membrane is perforated or burst, an escape of gas from the channel which is an exhaust without passing to the through the sealing portion, to pass through the cover and / or to bypass the sealing portion of the cover (the flow being diverted by the protective zone).

[0009] Thanks to these arrangements, effective thermal protection can be advantageously obtained for a region of the cover which is highly subjected to heat and which has a barrier effect against incandescent particles which are liable - in the event of a fault in this region covering the channel - to be propelled directly from the inside of the housing to the outside. The membrane, typically provided in a pressure compensation vent, may be flexible and partly fragile so as to no longer block the channel in a perforated or burst state. This state of the membrane may be obtained in the event of overpressure in the channel beyond an overpressure threshold, for example due to swelling which causes contact of the membrane against at least one suitable piercing tip or member.

[0010] The body may be based on a rigid material, possibly plastic, which is devoid of a radial or closing portion, with the possible exception of thin partitions. More generally, the body is provided with a side wall surrounding the gas circulation zone and is configured to connect, removably or permanently, to the housing at / on the opening of the housing. The body may optionally be designed as an annular projection of a housing component, or form an attached connection element.

[0011] The screen may be in the form of a layer, for example fitting the internal face of the cover, possibly completing a peripheral zone where several of the passageways are provided. A peripheral grid zone may be provided in the plastic cover part, while the screen may at least cover a solid central zone (without opening) of this cover part. Generally, it is understood that the screen may be offset (selectively offset) relative to one or more of the holes forming the passageways of the cover.

[0012] Typically, emergency exhaust is permitted with a distribution of the gas flow in the different passageways. The plastic cover part may include several passage orifices (possibly parallel to each other, in particular if they are in the form of slots) not covered by the screen. The screen may itself be slotted or perforated, so that at least partly the orifices or passageways are surrounded by the screen.

[0013] The gas can escape without pressure loss linked to the cover, for example with a part of the hood having an overall passage section (sum of the sections of the passageways) at least equal to the passage section of the channel, this overall passage section being accessible / not blocked by the screen. It is understood that very hot gases and possible flames will not be able to directly damage the plastic material of the part of the hood thus protected and reinforced.

[0014] The channel may be subdivided into different conduits delimited at the same opening of the housing, possibly with two or more membranes to distribute the fixing edges of these membranes. A structure with two parallel channels each covered by a membrane (one sealing membrane per channel) may be used, under the same cover. In this case, the device may provide a screen or a portion forming a screen, on the cover, opposite each channel.

[0015] The cover may have an internal face on which the screen is glued, possibly with a bonding zone surrounded by several of the passageways. A piercing member, carried by the cover and projecting from this internal face, may be surrounded at its base by the screen, the latter optionally being able to have one or more predefined openings, each delimited for example by an annular border.

[0016] In embodiments, the screen is flat, possibly planar, at least in a central area overlapping with a central closure portion, without a passageway, of the closure portion (within the cover part) made of plastic material. The screen may be substantially flat and of a thickness less than or equal to a thickness of the cover.

[0017] A plastic part can form the hood part (and thus the closure portion) of the cover and, more generally, a membrane protection function can be provided by the cover which is for example a skirted cover, fitted onto a peripheral part (typically annular) of the body. The body can: - partially fit into an interior volume of the cover delimited by the skirt, - delimit a gas circulation zone, downstream of the channel (and possibly downstream of at least one other channel in certain options), corresponding to an outlet zone of the channel(s) (this circulation zone extends between the screen carried by the cover and the membrane(s) associated with the channels). - axially retain the cover, for example by reliefs or lugs formed on an external face of the body (annular body), and / or by tabs forming gripping edges or grooves for the engagement of reliefs belonging to / carried by the skirt of the cover, in a configuration for protecting each membrane.

[0018] In embodiments of the device, the cover portion may have one or more of the following features: - the cover part is molded from a single piece of plastic material, preferably without an elastically deformable / flexible part in the closure part; - opposite the channel, a piercing member is carried by the cover, preferably by the plastic cover part, to perforate or burst the membrane in the event of overpressure in the channel (beyond an overpressure threshold). - the passageways comprise, in the cover, passageways distributed both around the screen and around the piercing member, at least part of these passageways being able to optionally be formed in a skirt of the cover part. - the screen has openings in a peripheral part overlapping with a skirt of the hood part. - all or part of the screen consists of a rigid metal structure with a central metal part and at least one folded side or an internal metal skirt, covered laterally by a skirt of the hood part. - the screen, at least in a protective zone overlapping the sealing portion, is impermeable to liquids and / or provided with pores of submillimetric size. - the screen is flexible / foldable (the material or structure constituting the screen being flexible / foldable). - the hood portion has narrow, preferably elongated, openings having a first width and forming part of a first group of peripheral openings. - the screen has narrow, preferably elongated openings, having a first width (possibly identical to that provided for the narrow openings of the hood part) and forming part of a first set of screen openings. - an inner skirt or sides of the screen is / are provided with narrow openings which overlap (from the inside) all or part of the narrow openings of the hood part. - the hood portion has one or more wide, circular, oval or rounded-edged openings, preferably having a diameter at least five times greater than the first width of any of the narrow openings of the hood portion, and optionally forming part of a second group of peripheral openings. - the opening(s) of the second group of peripheral openings (of the hood part) are arranged in corners of the closure portion or between the closure portion (which is typically a central portion of the hood part) and the narrow openings of this hood part, - the screen has wide, circular, oval or rounded-edged openings, preferably having a diameter at least five times greater than the first width of any of the narrow openings, and forming part of a second set of peripheral openings. - the openings of the hood part and / or the narrow openings of the screen are provided on a skirt and are elongated in a direction parallel to a longitudinal axis of the piercing member, which may be a direction perpendicular to the (radial) obturation portion.

[0019] In embodiments, the screen with the metal layer that can define the lower face can be maintained in the gas exhaust zone opposite an outlet of the channel (typically formed by the annular edge of the body / end plate) to form the impact zone of the fuel particles and more generally of the largest solid particles (particles that can be incandescent) ejected from the interior of the housing and likely to cause parts of a vehicle to burn if they were to rapidly degrade the cover and pass through it to then generate flames. The screen forms a stable and reinforcing part of the cover which makes it possible to greatly disrupt / delay, or even stop the dramatic sequence of thermal runaway followed by the fire spreading, which is observed in cases with ejection or melting of the cover without any further protection.

[0020] According to a feature, the cover is a pre-assembled part which integrates the screen before fixing this (pre-assembled) part on the connection support. Thus, the cover can be a pre-assembled part with for example an inner sub-cover or an inner layer allowing the metal layer to protect the closure portion / hood part. In a pre-assembled state, the cover (pre-assembled part beforehand) is fixed on the connection support. The connection support may incorporate a rigid perforated metal protective plate or metal grid (e.g. stainless steel). The membrane may be secured to the connection support, typically from above, corresponding to a side opposite the protective plate or grid. The membrane may be kept spaced from the protective plate or grid by partitions provided in the channel.

[0021] Typically, the connection support corresponds to a first pre-assembled part, including the body, the membrane and possibly the perforated plate or (metal) grid underlying the body, while the cover corresponds to a second pre-assembled part. The second part is mounted on the first part and remains attached to this first part, the fixing being permanent or resulting from a snap-fastening resistant to pressure variations in the channel, under the membrane.

[0022] The membrane may burst due to the pressure build-up in the channel, which is not the case for the housing and the connection support (with the body) mounted on the housing, knowing that the gas flow may escape massively (at very high flow rate for example) from the housing via the channel. The cover may remain in place while providing a large overall passage section, the passageways being able to include axial passage orifices offset from the channel and overlapping (facing) an annular peripheral fixing zone or region. An annular peripheral fixing region may optionally be formed in the connection support 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 sealing against the housing and a channel-delimiting wall which may be formed internally in the body.

[0023] In embodiment options, the body has a base wall or mounting flange and includes an annular channel-delimiting wall, which is a wall extending longitudinally, from a lower face of the base or mounting flange, to an upper edge where the membrane can be placed (and typically fixed). The body and / or a rigid metal protective plate may constitute a connection part which carries an annular sealing element, preferably housed in an internal groove of the base wall or flange. The internal groove may open axially opposite a sealing portion of the cover (sealing portion provided in the hood part), in order to achieve an annular seal with the housing.

[0024] 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. The upper face has a region of annular surface, substantially planar, on which the membrane is fixed or against which an edge of this membrane is pinched. The annular side wall of the body, serving to form the circumference of the channel, may extend longitudinally around a central axis between the flange which allows anchoring on 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 which projects from an outer annular shoulder of the flange. The flange is constituted for example by a rigid plastic part constituting the body, being able to be interposed axially between a metal protective plate or grid, arranged along the lower surface of the flange, and the membrane which is placed on the annular edge.

[0025] In embodiments allowing the screen to be secured to the cover / form part of the cover, one or more of the following features are provided: - the piercing member is configured to pass through the screen or be arranged between two adjacent portions of the screen and / or this piercing member extends in a direction axial 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 screen. - the piercing organ may be part of a group of piercing organs carried by the hood part. - one or more piercing organs may be included in the plastic part constituting the hood section. - the cover part allows attachment to a periphery of the body, for example by having attachment means on a skirt of the cover part, also allowing the screen to be supported to suspend it and keep it spaced from the membrane when the latter is at rest (for example in a flat configuration and typically attached to the body by a membrane edge). - the membrane and an inner face, facing the channel, of the screen are arranged parallel to each other, with a spacing. - the spacing between the membrane and the inner face of the screen corresponds to a sub-zone of an interior volume of the cover, for example delimited by a skirt of the hood part. 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 cover for management of the usual ventilation mode, while having safety in an emergency mode with massive gas escape, ensuring that the membrane is pierced and avoiding melting of plastic parts of which the cover is made, which prevents or delays the creation of flames.

[0026] The axial dimension of the piercing member may be provided to define a projecting axial extension from the metal layer, such that this extension is greater than a maximum thickness of the metal layer. Such a projecting axial extension may be significantly greater than an average thickness of the metal layer, for example when this thickness is substantially constant. For example, it exceeds double or triple the maximum thickness (or possibly the average thickness) of the metal layer. In other words, the piercing member may protrude from the rest of the cover in the area forming the spacing between the inner face (protective against the impact of incandescent / combustible particles from the channel) of the screen and the outer face of the membrane opposite the channel.

[0027] The screen may be attached to the cover portion to optimize the compactness of the device cover. The screen may have notches to avoid covering the openings of the cover portion from the inside. In options, the screen comprises an adhesive layer directly bonded to the cover portion. The adhesive layer may be inserted at least between the sealing portion formed in this part of the cover and the metal layer.

[0028] In options for producing the constituent structure of the screen, whether the structure is multi-layered or not, the screen can: - be separated (without contact at least in the area where it overlaps the canal) and spaced from the body. - be carried by the hood part forming an inner face of the cover. - have two opposite parallel faces, one of which is formed by the metal layer, and the other forms a contact layer for contact with a plastic material constituting a rigid structural part of the cover (hood portion). - be made integral with the cover by fixing and / or gluing means. More broadly, the fixing means for holding the screen in position may be heat-resistant, for example by including metal which is part of a structure fixed to the housing and / or by being fixing means arranged beyond the screen or arranged opposite the channel and thus behind the metal layer. An adhesive or glue material may form the contact layer.

[0029] According to a feature, the screen comprises a substantially planar portion parallel to a plane of the opening. The planar portion may be delimited by edges having a perimeter. The planar portion is longer than a diameter or largest dimension of an outlet formed by the channel, and / or the perimeter of the planar portion is greater than the inner circumference / perimeter of the channel (defining the outlet section of the channel, which is typically the outlet section where the membrane extends at rest). The screen may be traversed by a rod of the piercing member in the substantially planar portion. Alternatively or in addition, the screen may include a projection or point, oriented towards the membrane to form a piercing means, where appropriate forming the piercing member.

[0030] In certain embodiments, the screen is arranged with: - a screen thickness that is the same or less (thinner screen) than a thickness of the cover portion that forms the outer surface of the lid. - the metallic layer of the screen produced in the form of a part of film or sheet which constitutes a surface of the screen which is opposite the channel. - the part of film or sheet (which constitutes the metallic layer) forming one side of the screen which defines a surface directly opposite the membrane. - the flexible metal layer, this layer being able to fit the shape of the internal face of the plastic cover to be protected. - in the metallic layer, aluminum, steel (typically stainless), an alloy including one and / or the other of these elements. - a metal layer including or consisting of a metal mesh or metal lattice structure (for example a woven fabric). - wires or bundles of metal fibers integrated into the metal layer. - at least one layer of a thermally insulating fibrous material, for example interposed between a metal layer and the cover part. - ceramic fibers

[0031] A thermal insulation layer, for example made of ceramic or ceramic composite (where appropriate ceramic matrix composite), may optionally be interposed between the metal layer (typically with reinforced structure) and a layer forming the adhesive surface. It may also be glued and, before fixing to the hood part, bonded to a removable support for contact with the adhesive layer. This support, typically flexible, is removed when fixing to the cover.

[0032] In embodiments, the screen has a three-dimensional structure (predefined structure) and may have openings arranged laterally and axially, to distribute the passage section for the gas flow. The protective zone formed by the screen is an area without opening except for orifice(s) for the passage of a piercing member which joins the closure portion by crossing the screen. The screen may delimit a hollow space between flanks which are laterally offset relative to the protective zone (knowing that these flanks are not opposite and do not axially cover the channel).

[0033] In embodiments of the device, one or more of the following features are provided: - the screen has one or more folded or curved portions to cover (each) a portion of margin of the hood portion which is provided in a skirt of the cover or which is adjacent to the closure portion. - a metal element is provided running along the base face of the body, being arranged between the housing and the body, for example extending along a plane which intersects a seal carried in a groove in the body (groove with lower axial outlet for example). - the membrane extends between the screen and a metal element (protective element distinct from the body), for example perforated, which covers the opening of the case. - the body can be provided with partitions arranged in the channel. - the partitions allow a flat configuration of the membrane to be maintained in the event of depression in the channel. - the partitions have a first height and are axially more elongated / higher than the axial extension of the connection support for the cover. - the partitions, each sized with the same first height, are surrounded by the annular connection support, which is formed on an external shoulder of the body formed at a second height less than the first height (the first height and the second height each being measured from a base face of the body.

[0034] The device allows both pressure compensation of a battery case and emergency ventilation, typically by protecting the gas-porous membrane for its compensation operation. A pre-assembled design, without mobility of the locked cover, allows the device to be able to effectively close the opening of the case and maintain the integrity of the membranes, in an environment subject to vibrations. This is the case in particular when the battery case is mounted in a motorized vehicle, for example an automobile or other rolling machine. In embodiment options, the membrane (at least one membrane) is designed to ensure sealing against oil, water and dust. It can be made of hydrophobic material and / or form a water barrier.

[0035] It is permissible to achieve pressure management with a device provided with a cover that remains closed regardless of the operating mode. The assembly of the support part, with the membrane (complementary part of the cover), may involve a peripheral fixing region in the body, for securing to the housing and for fixing the cover, which does not interfere with the annular fixing zone of the membrane, which is located for example on a projection or an edge zone offset internally relative to the fixing region. In options, the membrane(s) may be deposited at an inner shoulder of the body or a transverse face (facing the cover).

[0036] According to one aspect, a method of assembling a ventilation device is provided which minimizes the risks of obstructing the area through which a gas flow must escape in an emergency, by melting plastic material constituting the sealing portion in the cover held in place over the corresponding opening of the battery housing(s).

[0037] To this end, a method is proposed for assembling a ventilation device for a battery case, using a screen capable of being mounted under a closing portion of a cover before connecting the cover to a body equipping the battery case by delimiting a channel forming an outlet through an opening in the case, the method comprising the steps essentially consisting of: - arranging a membrane transversely to an annular support or side wall of the body, the membrane being gas permeable to allow selective filtration of a gas stream flowing through the channel to leave the battery housing; - provide the cover in a pre-assembled state, with the screen included in or integral with the cover, the screen comprising a metal layer and forming a heat shield covering the sealing portion of the cover from below; - rigidly fix the cover on the body, so that the screen covers the channel and the membrane (membrane which is flexible and partly fragile so as to no longer block the channel in a perforated or burst state of the membrane obtained in the event of overpressure in the channel beyond an overpressure threshold); wherein passageways are provided in the cover or at the periphery of the closure portion, preferably in a plastic cover part which includes the closure portion.

[0038] The passageways may allow emergency escape of gas through the cover and / or by bypassing the closure portion. Typically, these passageways may be distributed in the hood portion and offset relative to the screen or a protective zone formed by the screen, to make the cover perforated.

[0039] In embodiments of the assembly method, one or more of the following arrangements may be adopted: - the screen is supplied in the form of a flexible sheet which is permanently fixed to an internal face of the hood part. - the screen includes a portion or thermal protection zone opposite an outlet of the channel, with at least one of a shape correspondence and a correspondence in perimeter / border dimensions, between the outline / border of the outlet and the outline of the thermal protection zone. - the holes in the cover are all offset laterally / radially outwards relative to the thermal protection zone which is part of a central zone of the gas-impermeable / gas-barrier cover (the cover part may also be solid, without opening, at the level of the overlap with this thermal protection zone).

[0040] According to certain options, the sheet or similar part (preferably gas-impermeable) constituting the protective zone arranged opposite the channel, is fixed by gluing or welding on an internal face of the cover part. With this arrangement, the screen is stiffened and attached to the closure portion. Additionally or independently of this type of fixing, the screen may be devoid of openings or slots, at least part of the passageways being able to be selectively offset in a peripheral region of the cover relative to the screen. Possibly, notches may make it possible to delimit edge sections without the screen being openwork. In other options, possibly with the screen also provided as a flexible sheet, the screen is provided with openings or slots, at least a portion of the passageways passing through the screen. Typically, the passageways may include holes in the cover portion that are aligned or overlap with the openings or slots in the screen.

[0041] The membrane may be fixed by a welding step carried out hot, 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 may thus be melted during the welding step. The membrane may be fixed in an annular welding zone and deformable in the sealing portion (permeable to gas) surrounded by this welding zone.

[0042] According to a particular feature, the cover has a skirt or a tubular portion capable of internally housing (therefore surrounding) a projection or insertion portion which belongs to the body. The body may for example have a hollow, annular projection or one with an annular side wall. A mounting / connection support may be formed by the body, which is for example made in one piece and optionally provided to axially cover a protective metal grid. A fixing of the body to the housing is enabled by fastening members (bolts, screws or other parts adapted to enable a rigid connection), for example by arranging all or part of the fastening members in a region surrounded by a gasket in contact with the housing. When holes are provided in the cover part, at least one / more of the fastening members are arranged directly above a corresponding hole in the cover part. Optionally, the device forms a pre-assembled ventilation unit that does not yet cover the opening of the battery housing. This results in a device forming a pre-assembled functional component, which can be mounted by screwing, quarter-turning, or other simple assembly operation on the region of the housing forming the opening (wide opening compared to the narrow openings closed by the flaps) of the housing. A simple fixing of this type can make it possible to obtain sealing thanks to a gasket added to the base / base of the device, while the cover or similar protective part remains in its non-sealed closing configuration, fully fitted onto the body constituting the connection support.The device can therefore be transported, packaged and delivered in a robust manner, with a cover whose hood part is without opening at least in a radial portion covering the channel, and makes it possible to limit the number of step(s) of installation of the device on the battery housing. The cover can be notched or provided with axial openings for the installation of the attachment members for connection to the housing while the cover is already secured to the body. Brief description of the drawings

[0043] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which: [Fig.l] is an exploded perspective view of a ventilation unit suitable for mounting directly on a wall of a battery box, in order to close an opening in this wall. [Fig.2A] illustrates, in perspective, half of a ventilation device having a similar assembly to that of the unit of [Fig.l] using a membrane for closing a degassing channel, directly above a metal screen carried by a cover. [Fig.2B] shows a detail of a metal shield such as that provided in [Fig.2A], which may be in the form of a multi-layer structure with a fixing layer for adhering to an inner face of a plastic cover portion of the lid. [Fig.3] is a partial top view of a metal layer screen, similar or identical to that provided in the ventilation unit of [Fig.l]. [Fig.4] is a perspective view of a ventilation device which may possibly be identical to that of [Fig.2A]. [Fig.5] shows an example of mounting the ventilation unit on an external face of a wall of the battery box. [Fig. 6A] shows, in a perspective view from above, an example of a connection support which can allow, on the one hand, fixing to the battery box, and fixing of a cover to cover the membrane carried by the connection support. [Fig.ôB] shows, in a perspective view from below, the connection support of [Fig.ôA] (without the attachment screws), with a protective grid placed at the end opposite that carrying the membrane. [Fig.ôC] shows, from a bottom view and after bursting / piercing the membrane, the ventilation unit (without the screws or attachment devices) with its cover which still covers the connection support so that a protection zone formed by the screen is located opposite the channel. [Fig.7] is a bottom view, in perspective, of a part of a cover made of plastic material without metal (or mineral material) with numerous orifices allowing the evacuation of gas at the periphery of a protection zone (typically central) of the screen. Description of the embodiments

[0044] Several examples of non-limiting embodiments are set out below in detail. In the various figures, identical references indicate identical or similar elements.

[0045] With reference to Figures 1, 2A, 4, 5 and 6C, there is shown a ventilation / pressure compensation unit which can be delivered as a pre-assembled unit, ready to close an opening O of a battery case by being mounted typically on the side of an external face of a shell or plate of the case P. In the following, this unit (possibly pre-assembled) is called ventilation device 1. In preferred options, the device 1 has a support part including or consisting of a body 2 allowing connection to the housing, being provided with fixing means PF2, for example formed as an annular flange or as insertion / retaining tabs for holding in position on the battery housing. The fixing means PF2 may be provided in a base of the body 2, which covers the housing P or which is optionally insertable (in part) inside the battery housing. The element or body 2 may consist essentially of a rigid connector, made of plastic material, optionally provided with a seal J mounted or added to this connector. The body 2 may have a flattened configuration, with a thickness (corresponding to a height) which is for example at least four or five times less than an external width or diameter.The body may be provided in one piece of plastic material, unreinforced or reinforced (for example by glass fibers, carbon fibers or the like) or similar molded material.

[0046] The body 2, of hollow structure and open at two opposite axial ends, is completed by a flexible and porous / gas-permeable membrane 5, which allows 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 can swell outwards in the event of slight suppression and can even be pierced if the overpressure presents a risk, by exceeding an overpressure threshold. In embodiments, such as for example in the case of [Fig.2A], 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 by any suitable fixing method allowing the cover 3 to be rigidly fixed.

[0047] [Fig. 5] shows a cover assembly 3 for which a single membrane 5 and a single screen 8 (formed for example from a block) are opposite each other for a flow deflection effect, peripheral with respect to the closure portion 30, which is compatible with: - ventilation in normal mode, in both directions DI (incoming) and outgoing (D2) following the direction of the central axis X, with the screen 8 underlying the obturation portion 30, - and emergency ventilation in direction D2, after release of the discharge end of the body 2 due to the degradation / burst of the membrane 5, which not only benefits from the deflection effect but proves to be robust in allowing the targeted impact of the combustible particles on a non-perforated protection zone ZP8 (in the overlap zone between the screen 8 and this portion 30).

[0048] The cover 3 has a closure portion 30, which can be visible from the outside, formed in a polymer part resulting from a molding (based on a thermoplastic material) or suitable plastic material. To prevent the risk of plastic loss in a very hot environment, particularly in the event of thermal runaway, the cover 3 is internally covered with a metal layer ML provided in a screen 8 which is arranged between one of the openings of the body 2 and the closure portion 30.

[0049] As clearly visible in particular in Figures 1 and 4, the body 2 may have a side wall 20, a lower end forming an open base, so that the body 2 delimits a channel C2 which opens out through an upper end of the body 2 which is an evacuation end closed by a membrane 5. Here the terms "lower" and "upper" do not prejudge the final mounted arrangement of the ventilation device but facilitate the explanation made with reference to certain of the figures. The channel C2 extends longitudinally between the base end and the evacuation end, typically around a central axis X of the body 2 which is an axis which can pass through / pass through the opening O in the mounted state of the ventilation device 1, as illustrated for example in [Fig.5]. The side wall 20 may be an external side wall of the body 2 which optionally includes a conduit or conduit element 200, as visible in [Fig.2A].

[0050] An annular edge 20' of the annular wall 20 may include a lower groove G2 ([Fig.l]) making it possible to house the seal J or sealing element, for example in the form of a ring, radially spaced from the conduit element 200 surrounding the path or channel C2 for the circulation of gas. More generally, the side wall 20 may carry a seal J by moving it away from the conduit element 200. The seal J may thus be spaced / moved away from an area of ​​evacuation of very hot gases in situations of overheating or thermal runaway.

[0051] The conduit element 200 is internally offset relative to the fixing region RF for the attachment of the cover 3 and for the sealed fixing to the housing P. The conduit element 200 may optionally be used for the fixing of the membrane 5, which is part of a pre-assembled assembly as shown for example in [Fig.6A]. This assembly may consist of the connection support SC and the membrane 5, with optionally a protective plate 4 integrated into this pre-assembled assembly. An annular portion 5c of the membrane 5 can be fixed in a sealed manner to one end of the pipe element 200. Of course, the fixing of the membrane 5, at the level of an annular portion 5c can also be carried out on another surface of the body or by pinching carried out in the preassembled assembly, in alternative embodiments.

[0052] In Figures 1, 2 and 4, it can be seen that the body 2 can have an annular radial portion which includes or forms the bottom of the groove G2 oriented towards the housing P, allowing to receive the annular J seal. The J seal may possibly have (before axial compression obtained by anchoring / fixing) a height typically greater than the depth of the groove G2 or at least is sized to protrude / overhang axially outside this groove G2. More generally, the J seal may project downwards (here towards the housing) thus presenting a surface which extends outside the groove G2 and capable of bearing axially against the battery housing. The annular faces delimiting the groove G may each have projecting ribs or reliefs for retaining the annular J seal. These reliefs or ribs, distributed in a spaced manner along the circumferential direction, project radially towards the inside of the groove G2.

[0053] The body 2 may have a projection 25 projecting axially from the annular radial portion which makes it possible to form the RF fixing region. As shown in particular in [Fig.4] and 6A, this projection 25 (tubular, rectangular or cylindrical) may axially extend the base of the body 2 so that the conduit element 200 extends from the base to an edge formed by the projection 25. Thus, an internal face of the conduit element 200 may be formed with an axial extension greater than the axial extension of the base where the annular RF fixing region extends. More generally, the device 1 typically forms at least one channel C2, preferably delimited by a circumference of the conduit element 200 which can protrude on an evacuation side relative to the rest of the body 2. The channel C2 can be used 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 certain variants, for example using at least one non-return valve, it may be provided that channel C2 is used only for air evacuation.

[0054] The channel C2 of the body can be in different forms with, in certain cases, the possibility of forming different evacuation paths downstream of the opening O. In the illustrated cases, the channel C2 is delimited by the conduit element 200 and / or a part of the body 2, in order to guide a gas flow FG escaping from the housing P through the opening O (the flow leaving through the opening passing entirely through the channel C2). In the non-limiting case of [Fig. 4], a channel C2 is shown subdivided into sub-channels SC2 due to the presence of separating spacers or partitions 22 which can crisscross the channel and make it possible to distribute the gas flow / flow FG.The configuration with spacers or crosspieces / partitions, distributed at several levels or elongated along the direction of the central axis X, can limit the propagation and the extent of flames which could form with the sudden evacuation of combustible particles near the opening O of the housing (where oxygen is present in abundance), in the event of overpressure with thermal runaway in the housing P. Integration, underlying the body, of an openwork protective plate

[0055] As visible in [Fig. 1], a protective grid or plate 4, for example made of metallic material, may be interposed between the housing P and the body 2 provided in plastic or similar molded material. The protective grid or plate is for example formed in a single piece, with a planar / flattened shape (therefore thinner than the body 2). The perforated protective plate 4 has a flame-limiting effect, by limiting the propagation of combustible particles and flames. An perforated zone or part of the grid G4, which may form an impact zone for combustible particles in the ventilation device 1, is placed in correspondence with the inlet of the channel C2, while a peripheral edge of the protective plate 4 is surmounted by the fixing region RF provided in an annular flange of the body 2, which extends around the conduit element 200.The border B4 of the grid part G4 can follow the edge of the entrance of the channel C2, axially covering this edge (therefore covering the entire perimeter of the entrance of the channel C2). The border B4 can be a continuous border, rectangular or directory-shaped for example.

[0056] Fastening tabs or members 4f (visible in [Fig.l] or 6C) are for example formed in the peripheral edge of the protective plate P4, in order to keep the latter attached against the base end of the body 2, by cooperating with complementary fastening members provided in the fastening region RF, for example in the form of clips CS projecting axially from a bottom 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 which is fixed to the body 2, by directly covering the channel C2 on the side opposite the membrane 5.

[0057] As described below, the protection provided by the protective plate 4 and / or by the partitioning of the channel C2 can be supplemented by a heat shield effect in a protection zone ZP8 not perforated for the passage of gas (or at least, in certain options, without having an opening larger than a submillimeter pore size). When the protective plate P4 is present and after bursting of the membrane 5, the protection zone ZP8 constitutes a second impact zone, different from the first impact zone in that it is not perforated by evacuation passages. These two impact zones are rigidly formed and / or reinforced to maintain a planar configuration, typically perpendicular to the central axis X. The protection zone ZP8 can be defined by the planar face F8 of the screen 8, 108 which is a face (inner face of the cover) oriented towards the membrane 5.

[0058] Fixing tabs 4p or other mounting parts, included in the protection plate 4, may be aligned with the fixing means PF2. When screws V or similar anchoring members are provided to pass through this plate 4 and an annular fixing flange or region RF of the body 2, it is optionally possible to use, in mounting holes / ducts which may constitute the fixing means PF2, split rings or metal members which constitute compression limiters 12, in order to form a contact interface with the plastic surfaces constituted for example by the housing P and the body 2.

[0059] The assembled ventilation device 1 comprises the cover 3 and is provided with its seal J, in order to close the opening O while ensuring that the gas exchanges are carried out with filtration by the membrane 5 or by a suitable number of membranes. In the non-limiting example of figures 1 and 5, it is understood that the seal J can rest on an annular seat zone 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 axially into contact with the housing P, on an external face of the latter. Fixing the cover to the body to maintain the protection area

[0060] The body 2, which may be made of rigid plastic material, includes a fixing region RF which makes it possible to attach and maintain the cover portion 9 of the lid 3 integral with the body. Clips or first fixing means FMI, MF1' are for example distributed / distributed on the periphery of the body 2, typically radially at a distance - with a radial spacing towards the outside - from the pipe element 200. Figures 1, 2 and 6A illustrate the non-limiting case of clips with a beveled face and an anti-removal effect of the lid 3. The fixing may be carried out by plastic deformation of the complementary fixing means FM2, FM2' or FM provided in the cover portion 9 which may be made of a single piece of plastic material. Axially projecting tabs FM2, FM may form at least part of the complementary fixing means / members.

[0061] The complementary fixing means FM2, FM2' or FM, by an elastic return effect in their initial shape, prevent the removal of the cover 3, so that the latter remains fixed to the body 2, whatever the temperature rise in the channel C2. This means that, if the screen 8, 108 were not present, the cover part 9 would not detach but would risk being broken and melted near its closing part 30 by closing off evacuation paths, before the fixing zone (further from the channel C2) is in turn degraded / broken if the thermal runaway continues. The configuration provided here, with multiple 03, 03' passageways and the shield corresponding to the protective zone ZP8, allows massive gaseous escape to be promoted without reducing the passage section for evacuation and minimizing the risk of deformation / alteration due to heat, which effectively prevents a state of overpressure from persisting with the associated overheating.

[0062] The hood part 9, which belongs to the cover 3, can be mounted on the body 2 (by being fixed at the periphery of the channel C2), by a skirt 33 or similar lateral part offset relative to the outlet of the channel C2 at the discharge end of the body 2. Thus, the additional fixing means FM2, FM2' may be part of the skirt 33 which also includes orifices constituting passageways 03'. As can be seen in particular in Figures 1-2, 4 and 7, the cover portion 9 may be provided with a plurality of openings 03, 03' making it possible to form openings in the cover 3 which are not, in the direction of the axis X, opposite the channel C2. For this, the cover portion 9 may be solid in a central zone, thus including a closure portion 30, typically not openwork, which combines with the screen 8, 108 to block an axial flow exiting the channel C2 so that no particle can exit in a straight line, parallel to the axis X, without avoiding an impact on the cover 3. This arrangement prevents the spread of fire, while ensuring that the cover portion 9 is protected from very hot gases and flames (reaching a situation of melting of the cover portion 8 requires much more time, for example at least 5 minutes).

[0063] However, as shown in Figures 1 and 2, a screen 8, 108 which forms the protection zone ZP8, by including a metal layer ML, protects the closure portion 30, for example by covering it completely to prevent the melting of plastic material present in the cover part 9. There is thus an overlap between a metal layer ML which can form the internal face of the cover 3 which is opposite the membrane 5 and the closure portion 30 which extends parallel to the membrane 5 in a closed configuration of the cover. The metal layer ML undergoes the impact of the combustible / hot particles in the event of runaway with the pierced membrane 5

[0064] The membrane 5 may optionally extend at the same level / at the same axial distance relative to the protective plate 4 and / or to the housing P, and possibly at the same axial distance from the protective zone ZP8 (distance for example at least greater than or equal to 5 or 7 mm from this zone, to allow possible swelling of the membrane 5).

[0065] The cover 3 may 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 options illustrated, 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 portion 9 of the cover 3. More generally, the cover 3 may be engaged on reliefs of the body 2, which in practice makes it possible to prevent accidental removal of the cover 3, for example in the event of a jolt when the housing P is on board a motor vehicle. Example of a drilling function integrated into the cover

[0066] With reference to figures 1 and 4, one or more piercing members 6, 6' are provided on the cover 3, oriented towards one or more zones of the membrane 5 which are each distant from the annular fixing portion 5c. In the non-limiting case of [Fig.l], the cover part 9 includes, opposite the channel C2, at least one first central piercing member 6. In addition, the cover part 9 can integrate at least two piercing members 6' offset along the direction of elongation of the cover 3, the latter being able to have a generally rectangular or non-circular format. Each piercing member 6, 6' is rigid and provided with a point or end adapted to tear / pierce the facing membrane 5, which swells in a protrusion above the discharge end of the body 2.

[0067] Whether the piercing member 6, 6' is produced in the form of a relief projecting from the cover part 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 perforate 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 members may extend parallel to each other, each being included in the same plastic part constituting a rigid component of the cover 3.

[0068] In the cover portion 9, the passageways 03, 03' may be distributed both around the screen 8, 108 and around the piercing member 6, 6'. In embodiments, the screen 8, 108 is adapted, with an insertion orifice 8a or predefined or pre-cut insertion orifices, to be fixed directly against the closure portion 30 while allowing each piercing member 6, 6' to pass through the screen 8, 108 by selective insertion into such an insertion orifice 8a. More generally, the piercing member 6, 6' can pass through the screen 8, 108 or be arranged between two adjacent portions of the screen 8, 108, so that the piercing member 6, 6' constitutes, within the cover 3, a point which is proximal to the membrane 5.

[0069] In preferred embodiments, the piercing member 6, 6' has an axial extension by having a narrow rod shape for example. It can extend in a defined axial direction, with for example a longitudinal axis of the rod of this piercing member 6, 6' which passes inside a perimeter delimited by an external edge of the screen 8, 108. In the non-limiting case of [Fig.l], each piercing member 6, 6' can be distant from a skirt 33 of the cover 3 and distant from any flaps R8 or curved parts / inner skirt belonging to the screen 8. Non-limiting achievements of screen production

[0070] The screen 8, 108 may be rigid, flexible or partially flexible. In the cases of Figures 1 and 3, the screen 8 is or includes a shell based on a metallic material. Margin zones ZM1, ZM2 are provided in an annular transition zone between the non-perforated protective zone ZP8 and lateral parts of the screen 8. The zone protective ZP8 is provided in the center of the screen 8 to be able to cover a surface identical to or greater than the outlet surface of the channel C2. The lateral part or parts of the screen 8, which include for example a skirt or flaps R8 to laterally cover the body 2, typically on the outside, have multiple slots or openings so that the cover 3 can have lateral gas evacuation channels, formed by superposition: - passageways 03' of the hood part 9 (openings / slots in the skirt 33), - and slots or openings 08' provided in the lateral periphery of the hood part 9.

[0071] With this arrangement, the screen 8 with metal layer ML can extend the main thermal protection effect, provided in the radial non-perforated protective zone ZP8, by a thermal protection effect at the margin by overlapping / covering the plastic bars or similar plastic members which form the periphery of the closure portion 30. With reference to [Fig. 3], two margin zones ZM1, perforated, can be arranged parallel in the radial portion of the part forming the screen 8. Two other margin zones ZM2, also perforated, are also provided perpendicular to the margin zones ZM1, in order to have axial openings in the cover 3 in a peripheral region offset radially outwards relative to the duct portion PC of constant section generated from the evacuation / outlet end of the channel C2 (this duct portion PC being formed in an interior volume V3 ([Fig. 7]) of / under the cover part 9). Such axial openings can make it possible not to block the passageways 03, 03' provided in the cover part 9, with typically a superposition of the orifices 08, 08' and these passageways 03, 03' in the fixed state of the screen 8 on the cover part 9.

[0072] More generally, the screen 8, which is for example thinner than the cover part 9, can form an openwork heat shield only around the protective zone Z8 which adjoins / covers the closure portion 30.

[0073] With reference to Figures 2A-2B and 4, the case of a screen 108 in the form of a flexible sheet directly bonded to the closure portion 30 is illustrated. In this case, the skirt 33 and / or the perforated zones at the periphery of the cover portion 9 may not be covered internally by a metallic material of the layer ML. The radial spacing towards the outside of this periphery of the cover portion 9, where a large cumulative section for the evacuation of gas is formed, may be sufficient to minimize the risk of fall / return of molten plastic into the channel C2. In practice, the temperature rise at the periphery of the cover portion 9 is less rapid than in the closure portion 30 located directly in the axial exit path of the gas flow FG.

[0074] [Fig.2B] partially illustrates a flexible sheet which makes up the part of the screen 108 intended to cover and be fixed in overlap with the closure portion 30. In addition to the metal layer ML, which may be a metal mesh, to form the covering face F8 on the inner side of the cover 3, a thermal insulation layer CL, for example based on a ceramic material, may optionally be provided between the metal layer ML and the cover portion 9. The screen may comprise an adhesive layer FL or equivalent attachment layer, directly bonded to the cover portion 9. The adhesive layer FL may be interposed at least between the sealing portion 30 and the metal layer ML.

[0075] When a rigid piercing member 6, 6' is provided in the closure portion 30, the sheet constituting all or part of the screen 108 can be locally perforated, with an insertion orifice 8a. This arrangement is also applicable in an embodiment with a rigid screen 8, as visible in the case of [Fig.l]. In variants, a piercing can be obtained by a point or piercing member provided directly in the metal layer ML or at least in the screen 8 (which has such a metal layer ML). Example of the creation of passageways on the periphery of the protective zone

[0076] The body 2 can provide unidirectional guidance of the gas flow or stream FG exiting through the opening O, with, where appropriate, the partitions 22 which participate in a linear guidance effect, so that any incandescent / combustible particles are driven axially towards the impact shield formed by the screen 8, 108, in the protective zone ZP8 which is axially aligned with respect to the outlet of the channel C2, in the discharge end formed by the body 2. The deflection provided by the cover 8, 108 can be carried out at 360°, in particular in the radial directions. The presence, in the cover portion 9, of passageways 03' which open laterally towards the outside via the periphery of the cover, facilitates an escape following this deflection effect. In addition, an edge exhaust is also permitted when the hood portion 9 includes orifices 03 (clearly visible in [Fig.4] or in [Fig.5]) which open axially and in the same general direction as direction D2, with a position offset (eccentric position) however in relation to the perimeter of the protective zone ZP8 which is set at least equal to the perimeter of the outlet of channel C2 at the evacuation end.

[0077] Referring now to [Fig.7], the cover part 9 which can fit / fix onto the body, in order to cover the channel C2 in a non-sealed manner, can have different sizes for the passageways, with: - the large openings 03 adjacent to the protective zone ZP8 and to a face F3 for fixing the screen 8 or 108, - orifices or slots of intermediate section 31, 31', smaller than the section of the large openings 03, which may be provided in a margin zone of the radial portion of the cover part 9, around the non-perforated closure portion 30 (and possibly interposed between two of the large openings 03), in order to facilitate axial gas escape adjacent to the protective zone, and - orifices or slots 32 of reduced section, which is a section smaller than the intermediate section, distributed in the skirt 33 or similar side wall of the cover part 9 made of plastic material.

[0078] Projecting segments, constituting barrier walls W (curved in C for example), can project axially inwards from the inner face F3 of the cover part 9, bordering a part of the large openings O3 on a radially inner side, as visible in [Fig.7]. These barrier walls W intersect particle leakage paths coming from the channel C2 and can limit the risk of incandescent / combustible particles coming directly out of the ventilation device 1, which has a protective effect on the environment close to the device (anti-fire propagation effect). When the screen 8 is in the form of an interior secondary cover or includes a rigid part with large openings 08, these are typically superimposed with the large openings 03 (which forms axial, off-center conduits of the cover 3), it is understood that the barrier walls W can be formed only in one of the screen 8 and the cover part 9.

[0079] As illustrated in [Fig.3], openings or slots 81, 81' and 82 may be formed with a correspondence in shape (geometry) and size with the corresponding openings or slots of the cover part 9, here respective openings or slots 31, 31' and 82. In other words, the orifices or slots 82 (closer to the non-perforated protective zone ZP8) are of reduced section, therefore smaller than the orifices or slots 81 or 81'. These openings 81, 81', 82 may each be of smaller section than any of the large openings 08.

[0080] Whatever the distribution adopted in the cover part 9 for the orifices / slots, with a dimensioning adapted to obtain a cumulative passage section possibly identical or similar to the section of the outlet of the channel C2, it is understood that the cover 3 is made heat-resistant at least in the overlap region between the metal layer ML of the screen 8, 108 and the closure portion 30. Embodiments with a three-dimensional structure of the screen 8, with a peripheral screen region perforated to allow the gas to reach the passageways 03, 03', may be preferred when the channel C2 and / or the sub-channels SC2 have(s) a width at least equal to the height of the body 2 with higher oblique trajectory probabilities for solid particles carried by the flow.

[0081] The cover 3, pre-assembled with the screen 8, 108 typically glued or welded to be held in a protective position, parallel to and permanently fixed to the cover part 9, therefore incorporates a metal layer which may be located for example less than 15 or 20 mm from the channel C2. In a normal ventilation mode, this cover 3 effectively protects the membrane 5, all the passageways for the gas being for example offset radially on the periphery of the cover 3, that is to say at the level of its external skirt 33 and possibly in a position adjacent to the junction of this external skirt 33. Thus, as in the case of the outgoing gas flow FG, the gas flow entering the ventilation device 1 cannot be kept unidirectional to reach the channel C2 via the membrane 5. More broadly, in preferred examples, at least two changes of direction are necessary to pass from the C2 channel to the outside of the device and vice versa.

[0082] The cover portion 9 may be of simple design, for example by molding in a single piece of plastic material. The cover 3 is for example devoid of any support or relief for retaining any seal. Here, the cover portion 9 has a main closure portion 30 (radial portion here) which may correspond to a bottom portion, from which extends a tubular side wall, forming the external skirt 33 of the cover 3. Assembly example

[0083] The body 2 can directly support all the other elements of the device 1, namely the seal J, the protective plate 4 which can be elastically fitted under the body against its base, the membrane 5 being able to be welded or added with a sealed annular contact, the perforated protective part, typically in the form of a cover 3, surrounding the opening O of the wall of the battery housing P.

[0084] The screws V or attachment members allow the body 2 to be mounted in or around the opening O, against the housing P, delimiting the channel C2, formed directly above the opening O or more generally following the longitudinal direction of the body 2 (along the central axis). In the mounted state, the cover 3 is kept spaced from the wall P by the base of the body 2.

[0085] Before this mounting on the housing P (final mounting), an assembly of the device 1 may be carried out, which constitutes a pre-assembled ventilation unit. This assembly may include, and possibly begin with, the step of welding the membrane 5 which is optionally carried out hot, typically by using vibratory energy so as to melt a temporary relief provided on the conduit element 200. The overlapping zone with each margin zone / annular portion 5c membrane can be converted into a fusion zone, with the obtaining of a welded annular part.

[0086] Optionally, the use of a flat sonotrode may be preferred. This may be arranged and moved, circularly here, over the annular overlapping / covering region between the annular edge of the membrane 5 and the top of the driving element 200. The sonotrode melts at least this top / contact portion and “glues” the membrane 5, pressing it (with an axial contact force) onto the heated / softened material of the body 2.

[0087] As clearly visible in Figs. 1 and 6A, a shoulder may be provided in the body 2, at the level of the fixing region RF to allow clips to be made both on the base (fixing means FMI') and on the periphery of the base of the body 2 (with the fixing means FMI each projecting laterally on one side of the body 2). This makes it possible to fix the cover 3 in a zone radially offset towards the outside, relative to the welding zone of the membrane 5. More generally, each membrane 5 may be fixed on only one same axial face of the body 2, by closing a channel C2 provided in this body 2.

[0088] When a flexible sheet is provided to constitute the metal layer or one of the metal layers of the screen, it is previously fixed on the cover part 9 while having a thickness less than 4 or 6 mm and / or much less than an axial spacing distance between the outlet of the channel C2 and the radial portion provided in the plastic cover part 9.

[0089] The ventilation device 1 can form a compact arrangement, responsive to an emergency situation in the housing P, which can advantageously avoid harmful damage, prevent the spread of fire, while ensuring that the cover part 9 is protected from very hot gases and flames. Thus, the time required to melt the cover part 9 is much greater, so that a return to equilibrium with cooling can be achieved without external damage to the housing and this before cover plastic flows to block the channel C2.

[0090] The present disclosure is not limited to the embodiments described above, only by way of example, but it encompasses all the variants that a person skilled in the art may envisage within the framework of the protection sought.

[0091] For example, different ways of releasing the channel C2 may be provided 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 recourse to a perforation tip provided that the level of deformation required for such rupture is reached only if an overpressure threshold is exceeded (on the channel side / inside the battery box).

[0092] Furthermore, the expression battery case must be understood in a general sense, the case being able to contain one or more groups of accumulators capable of providing energy in electrical form or energy usable in any form for conversion into electrical energy.

[0093] 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 here vertical, other arrangements are permitted, in particular with a ventilation unit mounted laterally on the battery housing.

Claims

Claims

1. Ventilation device (1) for a battery housing, in particular for a housing comprising one or more batteries, the device (1) comprising: - a body (2) provided with a side wall and connecting to an opening (0) of the housing; - a channel (C2), delimited by a conduit element (200) and / or a part of said body (2), for guiding a gas flow (FG) escaping from the housing through the opening (0); - a gas-permeable membrane (5), carried by the body (2) closing the channel (C2), the membrane (5) constituting a filtration part capable of retaining dust and / or water, the membrane being flexible and partly fragile so as to no longer close the channel (C2) in a perforated or burst state of the membrane (5) obtained in the event of overpressure in the channel (C2) beyond an overpressure threshold;and - a cover (3), comprising a plastic cover part (9) secured to a peripheral connection support (SC) provided in the body (2), covering the membrane (5); characterized in that the ventilation device (1) comprises a screen (8; 108) with a metal layer (ML), the screen (8; 108) being separate from the membrane (5) and included in or secured to the cover (3) by forming, in a protective zone (ZP8) provided in the screen (8; 108), a heat shield interposed between the channel (C2) and a closure portion (30) of the cover (3) which is opposite the channel (C2), and in that passageways (03, 03') are provided: - in the cover (3), in the cover part (9) and offset relative to the protective zone (ZP8), so that the cover (3) is perforated; - and / or laterally between the cover (3) and the body (2);and allow, when the membrane (5) is perforated or burst, an escape of gas coming from the channel (C2) which is an emergency escape without passing through the closure portion (30), to pass through the cover (3) and / or bypass the closure portion (30) of the cover.;

2. Device according to claim 1, comprising opposite the channel (C2) a piercing member (6, 6') carried by the plastic cover part to perforate or burst the membrane (5) in the event of overpressure in the channel (C2) beyond an overpressure threshold, in which the passageways (03, 03') comprise, in the cover (3), passageways distributed both around the screen (8; 108) and around the piercing member (6, 6').

3. Device according to claim 1 or 2, in which the cover (3) is a pre-assembled part which integrates the screen (8; 108) before fixing this part on the connection support (SC).

4. Device according to claim 2 or 3, wherein the piercing member (6, 6') is configured to: - pass through the screen (8; 108) or be arranged between two adjacent portions of the screen (8; 108); and / or - extend in an axial direction defined by a rod of the piercing member (6, 6'), a longitudinal axis of the rod passing inside a perimeter delimited by an external edge of the screen (8; 108).

5. Device according to any one of claims 1 to 4, in which the screen (8; 108) comprises an adhesive layer (FL) directly bonded to the cover part (9), the adhesive layer (CA) being interposed at least between the sealing portion (30) and the metal layer (ML).

6. Device according to any one of claims 1 to 4, in which the screen (8; 108), separate and spaced from the body (2), is carried by the cover part forming an inner face (F8) of the cover (3) and has two opposite parallel faces of which: - one is constituted by the metal layer (ML); and - the other forms a contact layer for contact with a plastic material constituting a rigid structural part of the cover (3), the screen (8; 108) being made integral with the cover (3) by fixing and / or bonding means.

7. Device according to claim 2, alone or combined with any one of claims 3 to 6, in which the screen (8; 108) comprises a substantially planar portion parallel to a plane of the opening (O), and in which the screen (8; 108) is crossed by a rod of the piercing member (6, 6') in the substantially planar portion.

8. Device according to any one of the preceding claims, in which the metal layer (ML) of the screen (108) is made in the form of a part of film or sheet forming a face (F8) of the screen which defines a surface directly opposite the membrane (5).

9. Device according to any one of the preceding claims, in which the screen (8; 108) comprises at least one layer of a thermally insulating fibrous material.

10. A device according to any preceding claim, wherein the screen (8; 108) has one or more folded or curved portions each to cover a portion of margin of the cover which is part of or adjacent to the sealing portion (30).

11. Device according to any one of the preceding claims, in which the membrane (5) extends between an openwork metal element (10) which covers the opening of the housing and the screen, the body preferably being provided with partitions, arranged in the channel (C2) and making it possible to maintain a flat configuration of the membrane (5) in the event of a depression in the channel (C2).

12. Method for assembling a ventilation device (1) for a battery case, using a screen (8; 108) capable of being mounted under a closure portion (30) of a cover before a connection of the cover (3) to a body (2) equipping the battery case by delimiting a channel (C2) forming an outlet through an opening (O) of said case, the method comprising the following steps: - arranging a membrane (5) transversely relative to an annular support or side wall of the body (2), the membrane (5) being permeable to gases to allow selective filtration of a gas flow circulating in the channel (C2) to leave the battery case; - providing the cover (3) in a pre-assembled state, with the screen (8; 108) included in or integral with the cover (3), the screen (8;108) comprising a metal layer (ML) and forming a heat shield covering from below the closure portion (30) of the cover (3), the closure portion (30) belonging to a cover part (9) made of plastic material; - rigidly fixing the cover on the body (2), so that the screen (8; 108) covers the channel (C2) and the membrane (5), which is a flexible membrane with a fragile part so as to no longer close the channel; (C2) in a perforated or burst state of the membrane (5) obtained in the event of overpressure in the channel (C2) beyond an overpressure threshold; wherein passageways (03, 03') are provided in the cover (3) or at the periphery of the closure portion (30), preferably in the hood part (9), whereby, in the ventilation device (1), an emergency escape of gas through the cover and / or bypassing the closure portion is permitted by the passageways (03, 03') which are distributed around a protective zone (ZP8) constituted by the screen (8).

13. An assembly method according to claim 12, wherein the screen (108) is provided in the form of a flexible sheet which is permanently fixed to an inner face of the cover portion (9) which is arranged opposite the channel (C2), preferably by gluing or welding, whereby the screen is stiffened and attached to the closure portion (30), the screen (108) being devoid of openings or slots, at least a portion of the passageways (03, 03') being selectively offset in a region of the cover (3) peripheral to the screen (108).

14. An assembly method according to claim 12, wherein the screen (8; 108) is provided in the form of a flexible sheet which is permanently fixed to an inner face of the cover portion (9) which is arranged opposite the channel (C2), preferably by gluing or welding, whereby the screen is stiffened and attached to the closure portion, the screen (108) being provided with openings or slots, orifices in the cover portion (9) which are part of the passageways (03, 03') being in alignment or overlap with the openings or slots (08, 08') in the screen (108).

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