Bursting membrane and safety valve system comprising a bursting membrane

Abstract

The invention relates to a membrane for a breather valve for a device for storing energy in electrochemical form, comprising: - at least one 1st zone (2) made of felt or a woven material which allows air to pass through the membrane in both directions, at least when the pressure is lower than a 1st threshold (P1); - at least one 2nd zone (4), different from the 1st zone (2), which is intended to burst at a pressure (P2) higher than the 1st threshold.

Description

[0001] DESCRIPTION

[0002] Title: BURST MEMBRANE AND SAFETY VALVE SYSTEM CONTAINING A BURST MEMBRANE

[0003] TECHNICAL FIELD AND PREVIOUS ART

[0004] The invention relates to the field of energy storage means, in particular of the type used in vehicles, for example of the type for moving materials and / or people, these storage means implementing electrochemical type solutions.

[0005] The invention relates in particular to an application connected to batteries, especially lithium-ion batteries, which consist of a sealed casing containing a set of individual cells and, most often, electronic and power components for their interconnection and control. Battery technologies, now indispensable, are experiencing increasing energy density and evolving architectures. In the event of a major exothermic phenomenon occurring within the battery, such as thermal runaway or even a fire, the battery will release a large amount of energy and gas, necessitating the opening or rupture of a dedicated system, such as a venting valve.

[0006] Each cell in the battery will potentially experience a temperature increase during a thermal runaway of one or more cells. This will lead to the complete spread of fire within the pack or, more generally, the casing.

[0007] Once a fire is established within the battery compartment, it can spread to the surrounding area and then to any system equipped with the battery, such as a vehicle. It is possible, through ventilation systems, to limit the spread of heat and therefore the intensity of a battery fire.

[0008] Today, irreversible systems are available, but they are not very efficient at low pressures; these systems typically open at around 200 mbar. One advantage of this type of system is its larger flow area, which is generally greater than that of other, so-called reversible, systems. This larger flow area allows for higher flow rates.

[0009] But a situation can also occur in which the pressure resulting, for example, from internal overheating of the battery, does not require an irreversible opening.

[0010] No system is known that offers the advantage of a high flow rate in the event of a major exothermic event occurring in a battery, while also allowing evacuation with a reversible system in the event of a less serious event.

[0011] One objective of the invention is to have a membrane, which can for example be used in a valve, for example a breathing valve for a device for storing energy in electrochemical form, this membrane combining various functions, including an evacuation function but also a breathing function, which makes it possible to balance the pressure between the environment and the inside of a volume, for example containing a battery.

[0012] Another objective of the invention is to offer a solution, for example a valve, of a hybrid type.

[0013] Another objective of the invention is to provide a solution, for example a valve, with a certain opening precision. This opening precision allows for a clearer definition, particularly through simulation, of the thermal runaway transfer dynamics. It also enables the use of multiple valves that open at the same pressure level, which is impossible with solutions comprising only a single burst valve within the battery in the event of an incident not requiring irreversible opening.

[0014] Another objective of the invention is to provide a solution, for example a valve, with different functions, including opening and / or bursting. Yet another need is for a valve that combines various functions, such as a discharge and / or bursting function and / or a venting function. While different valves are currently used to perform these different functions, this requires different assemblies, resulting in a complex system. It would be preferable to have a single assembly.

[0015] Yet another need is for a new valve structure that can combine various functions in different areas of the valve.

[0016] DESCRIPTION OF THE INVENTION

[0017] The invention relates first to a membrane, for example or particularly for a breathing valve for an electrochemical energy storage device, this membrane comprising:

[0018] - at least one l ère zone allowing respiration, in both directions across the membrane, at least for a pressure (or a pressure difference between the two sides of the membrane) less than one er threshold (Pi);

[0019] - at least one 2 ème zone, different from the l ère zone, designed to burst at a pressure (or a pressure difference between the 2 sides of the membrane) above 1 er threshold (Pi).

[0020] According to various achievements:

[0021] - the membrane is flat;

[0022] - and / or the 2 zones are juxtaposed;

[0023] - and / or one of the two zones surrounds the other zone;

[0024] - and / or each of the zones has an outer boundary:

[0025] * circular or elongated or oval in shape, for example one area being ring-shaped, and surrounding the other area, which is central, disc-shaped;

[0026] * or square or rectangular or polygonal in shape, for example, again, an area surrounding the other area, which is central;

[0027] - and / or the l ère zone and the 2 ème zones are fixed to each other, for example by welding;

[0028] - and / or the l ère zone and the 2 ème areas are fixed or assembled on or with the same support, for example a film or an adhesive layer;

[0029] - and / or the 2 ème zone forms a thin layer or a multilayer and / or is made of a plastic or metallic material, for example a polypropylene or polyethylene type material, or e-PTFE; alternatively, the 2 èmeThe area may be made of natural or synthetic fiber(s), or hemp, or coconut; - and / or the l ère area is made of a porous material, for example e-PTFE or perforated silicone or fibrous material.

[0030] Alternatively, the l ère The area can be made of felt or a woven material.

[0031] The material constituting all or part of the membrane may include at least part of a hydrophobic and / or waterproof and / or oleophobic property and / or be provided with a hydrophobic and / or oleophobic coating and / or the membrane may include at least one waterproof part.

[0032] According to an example of implementation, the l ère an area of ​​a membrane according to the invention has a flow rate between 0.2 and 3.5 l / min / cm 2 for example when the pressure difference between the inside and outside of the storage volume is 20 mbar.

[0033] The invention also relates to a valve for an electrochemical energy storage device, this device comprising a casing, this valve itself comprising:

[0034] - a valve body;

[0035] - at least one l ère membrane, which may be, according to a membrane, the invention as described above and in the remainder of this application, capable at least of bursting for a pressure difference between its 2 sides exceeding a threshold (Pi) and means forming at least one 1 er support of the said l ère membrane;

[0036] - means maintaining the valve in a closed state for a pressure difference between the 2 sides of the diaphragm less than (P2), Pi > P2 and allowing the valve to open when this pressure difference is between (Pi) and (P2).

[0037] The 1 er support door said l ère membrane.

[0038] The valve opens by opening the support, which carries the diaphragm, relative to the body. The support therefore moves away from the body.

[0039] The valve is closed by holding the support relative to, or against, the valve body. After the valve has opened, it is closed by closing the support relative to the body (the support, which carries the diaphragm, thus moves closer to the body) and returning the support to its position against the body. The valve body is designed to be fixed to the casing of the electrochemical energy storage device. Fastening means, such as screws or rivets, are provided for this purpose, allowing the body to be secured to the casing. The support can move relative to the valve body, for example, by translation along an axis, preferably substantially perpendicular to the wall in which the valve is installed.

[0040] The lère membrane can be held against the support using retaining means, for example a grid and / or a ring.

[0041] Preferably the l ère The membrane is waterproof.

[0042] According to one achievement, the l ère The membrane is a membrane according to the invention, further allowing at least one respiration by circulation of fluid through this membrane. In a valve according to the invention, the support means can be arranged at one end of a piston, which passes through the valve body.

[0043] The means of maintaining the valve in a closed state keep it closed for a pressure difference less than (P2) and allow the valve to open when this pressure difference is between (P1) and (P2); for example, these means include at least one spring, such as a straight or spiral spring, each bearing against a fixed part of the valve body and a movable part, attached to the support, which includes, for example, a stop. The properties of this spring and its degree of compression between the supports will determine the opening pressure of the valve.

[0044] The invention also relates to an energy storage enclosure in electrochemical form, for example of battery type, comprising an envelope containing one or more energy storage elements, this envelope being equipped with at least one valve according to the invention.

[0045] The invention also relates to a vehicle, comprising a passenger compartment and / or a storage area, an engine, and at least one energy storage chamber according to the invention. The invention also relates to a method of operating a valve of an energy storage chamber in electrochemical form according to the invention, a method in which: a) - the valve is held in a closed state for a pressure difference less than (P2); b) - the valve is in an open state for a pressure difference between (Pi) and (P2), Pi > P2; c) - the diaphragm bursts for a pressure difference greater than (P2).

[0046] For example, the membrane has at least a breathing part and there is fluid exchange between the inside and outside of the enclosure through the membrane at least during step a).

[0047] BRIEF DESCRIPTION OF THE DRAWINGS

[0048] [Fig. IA] - [Fig. IB] - [Fig. IC] - [Fig. 1D] represents various aspects of examples of realization of a membrane according to the invention;

[0049] [Fig. 2A] - [Fig. 2B] - [Fig. 2C] - [Fig. 2D] - [Fig. 2E] represent various aspects of an example of an embodiment of a breathing and bursting valve which may include a membrane according to the invention;

[0050] [Fig. 3A] - [Fig. 3B] - [Fig. 3C] represent various aspects of another example of an embodiment of a valve equipped with a membrane according to the invention, comprising a breathing zone and a bursting zone;

[0051] [Fig. 4A] - [Fig. 4B] - [Fig. 4C] represent various aspects of another example of the embodiment of a valve equipped with a bursting membrane according to the invention;

[0052] Figure 5 represents an enclosure of an energy storage device comprising a valve according to the invention and a discharge valve.

[0053] Figures [Fig. 6A] - [Fig. 6B] - [Fig. 6C] - [Fig. 6D] represent various vehicles or machines, automobile, airplane, boat, locomotive, equipped with an energy storage device comprising a valve according to the invention as well as a discharge valve.

[0054] DETAILED DESCRIPTION OF SPECIFIC METHODS OF IMPLEMENTATION

[0055] Figure IA shows a first example of an embodiment of a flat membrane 1 according to the invention. It comprises:

[0056] - a l ère zone 2, allowing respiration in both directions across the membrane, perpendicular or substantially perpendicular to the plane defined by it, for a pressure difference between the two sides of the membrane less than one er threshold (Pi);

[0057] - a 2 ème Zone 4, known as the bursting zone, is designed to burst when there is a pressure difference between the two sides of the membrane above the 1 erpressure threshold Pi, the two zones being juxtaposed and fixed to each other.

[0058] In Figure IA, the membrane has a first central zone 2, disc-shaped, surrounded by the 2 ème zone 4, ring-shaped. Alternatively (not shown), the distribution of the two zones can be the reverse of that in figure IA, with the membrane having a first (respiratory) ring-shaped zone, which surrounds the 2 ème bursting zone, which is central, disc-shaped.

[0059] Alternatively (Figure IB), these zones can be elongated or oval-shaped, with one of them (here, zone 2a, allowing respiration) positioned in the center and surrounded by the other zone (here, zone 4a, bursting zone). Again, the distribution of the two zones can be reversed.

[0060] Alternatively (figure IC), each of the two zones can be square, rectangular, or more generally polygonal:

[0061] - one of the two zones 2b (respiration) being surrounded by the other 4b (burst): this is the case of figure IC, the 2 zones can be reversed;

[0062] - one of the two zones 2c (respiration) being juxtaposed with the other 4c (burst), here again the 2 zones can be reversed; this is the case of figure 1D.

[0063] Other shapes and / or distributions of these zones can be achieved.

[0064] The l èreZones 2, 2a, 2b, and 2c of the examples described above allow for respiration; they are, for example, made of a porous material, with air porosity defined by the airflow rate in L / min / kPa. The flow rate of a porous membrane is defined at a certain pressure level, as it is the pressure difference between one side and the other of the membrane that creates a mass exchange over a specific surface area. Thus, membranes commonly used, for example, in battery applications, can have a flow rate of 0.2 to 3.5 L / min / cm². 2For example, when the pressure difference between the inside and outside of the storage volume is 20 mbar. The material in question could be, for example, e-PTFE (Gore-Tex), perforated silicone, or a fibrous material, such as felt. e-PTFE is composed of 100% perfluorocarbon material. This material has the advantage of combining breathability with hydrophobic and oleophobic properties, making it a good material for a breather solution that also provides protection against liquids and solid particles. Felts or other woven materials, for example, those made from animal, plant, or synthetic materials, can also be used. In this case, while these materials can be filtering, they may be less effective in terms of water and dust resistance.A simple felt or fabric can be coated with a hydrophobic and / or oleophobic finish, which, however, may degrade its air permeability. The level of protection it provides against dust and water is defined, for example, by the IP67 standard or certification. The protection rating will depend on the intended use of the room in which the membrane is incorporated, for example, exposure to the external environment: for IP67, immersion for 30 minutes under 1 meter of water is considered; IP68 can also be considered, depending on the application, with immersion for 200 hours under 2 meters of water.Breathing membranes, breathing and bursting membranes, and bursting membranes can be resistant to projection and in this case they can simply be made of felt; but, in the case of long immersion, the pore size can be smaller and the level of surface tension of the material to resist these stresses will be greater.

[0065] The 2 ème zone 4, 4a, 4b, 4c designed to burst for a pressure difference above 1 erThe threshold Pi, for example, is a completely sealed membrane. It can be, for example, a thin film or a multilayer membrane. It is made, for example, of a polypropylene or polyethylene type material, or a plastic material, or of an e-PTFE type material (for example, with a different thickness and / or air permeability characteristics than those mentioned above, for example, to be more airtight). Alternatively, it can be made of a natural material, for example, natural or synthetic fiber(s), hemp, coconut fiber, etc.

[0066] In general, in this application, the burst pressure level can be defined either by the material's resistance to tensile stress (dependent on Young's modulus expressed in MPa), or as the strength of the membrane weld to a component (e.g., a support or piston, also made of plastic), or as a temperature resistance level. Therefore, the burst pressure level can be adjusted using one or more of these parameters.

[0067] The two zones or the two parts of the membrane can be joined:

[0068] - for example by means of a film 3 provided for this purpose (figure IC, but this film is applicable to the other examples); this film deposited on the membrane has adhesion properties; it is for example a PE (Polyethylene) film used to allow thermal adhesion; - or by means of an adhesive 3' intended to be deposited on a support such as the support 24 shown below (figure IC, but this adhesive is applicable to the other examples);

[0069] - or by a weld 5 (Figure 1D) via a heating process of the membrane or plastic; this is, for example, a heat-sealing process commonly used for materials such as aluminized polypropylene or polyethylene films, like those used for sealing films for vacuum food packaging; alternatively, they can be welded using an ultrasonic process. This weld 5 is applicable to the other examples (Figures 1A-1C).

[0070] In cases where water tightness is less critical (for example, with only resistance to water splashes and not to immersion under one or more meters of water for 30 minutes to several hours), the two parts 2 (respectively 2a, 2b, 2c) and 4 (respectively 4a, 4b, 4c) of the membrane can be held mechanically, for example, by locking (in the devices shown below, between the piston and a clipped cover) without welding. A membrane according to the invention, as described above, can be used in a breathing valve for an electrochemical energy storage device.

[0071] Figures 2A - 2E represent aspects of an example embodiment of a valve 20 that can incorporate a membrane according to the invention, for example as described above.

[0072] It comprises a fixed body 10, intended to be fixed in a dedicated opening in the casing 30 of an electrochemical energy storage device, for example, a battery pack. In Figure 2A, this body 10 is shown in place in the dedicated opening of the casing 30. It is fixed, for example, by means 11, 1a, which may be attached, welded, or crimped; these are, for example, screws or rivets. These means 11, 1a are preferably sealed or equipped with means (one or more seals) that ensure their sealing. The body 10 is provided or traversed by one or more orifices 10i, IO2 IO3,... (see figure 2E), through which a material, for example a fluid, will be able to flow during respiration, in a direction going from the outside of the valve, towards the inside of the valve, or vice versa, depending on the pressure difference on either side of the valve.It can also be provided with a central orifice lOo through which a piston (or rod or bar) 8 of a support 24 (described below) will be able to move.

[0073] The internal volume of the casing and valve is designated by the reference Vi, the external volume by the reference V e .

[0074] A seal 29 can provide a seal between the periphery of the body 10 and the casing 30. In this example, this body has rotational symmetry about an axis AA'. However, other shapes can be achieved, particularly depending on the shape of the different zones of a membrane, as already explained above for certain membranes according to the invention. The body 10 can include an outer circular lip 22 on which a support 24 for a flat membrane 100 can be positioned. This membrane 100 is a membrane according to the invention: it can be detached or destroyed (by explosion or bursting) by a certain pressure difference between the two sides of the membrane, for example, a pressure difference Pi - P e between the interior volume and the exterior volume greater than or equal to Pi.

[0075] The support 24 may be grid-shaped or have ribs arranged in a star pattern around the center (Figure 2C); it may be fitted with a circular reinforcement 24 r between the center and the periphery (figure 2D). It can be between:

[0076] - a l ère mainly flat face 24j (this face is turned towards the inside of the enclosure when the valve is mounted on it);

[0077] - a 2 ème mainly flat face 24 e (this face is turned towards the outside of the enclosure when the valve is mounted on the latter), against, or opposite, which the membrane 100 can be applied.

[0078] The support 24 is itself equipped with or traversed by one or more orifices 24i-24s...(see figures 2C and 2D) through which a material, for example a fluid such as air, can flow during respiration, after having passed through the membrane, in a direction from outside the valve, or the 2 e side 24 e from support 24, towards the inside of the valve, or towards the l ère face 24j of the support 24 or in the opposite direction, before passing through the membrane. It may also be equipped with a piston (or rod or bar) 8, to one end of which it is fixed. The fluid also flows through the membrane 100 carried by the support 24.

[0079] The body 10 may include or be extended by a central cylindrical part 6, which extends towards the inside of the casing and in which the piston 8 will be able to slide.

[0080] At least one compression spring 12 holds the support 24 in a normally closed position against the body 10, thus allowing, through the membrane 100 it carries, circulation of atmosphere, liquid, fluid, or material between the inner volume Vi and the outer volume V e of the envelope, in one direction or another, perpendicular or substantially perpendicular to the plane defined by the flat membrane 100.

[0081] The precision of the spring determines the opening precision. Ideally, a precise or very precise spring is used, allowing the valve to open at low pressure, for example, to within a few millibars of pressure and with a very good tolerance of less than 7%. It is also possible to easily vary the pressure level by choosing a spring with a higher or lower stiffness.

[0082] Stiffness and opening force are therefore two parameters influencing the opening of the valve.

[0083] A lateral seal 15 can be arranged between the periphery of the support 24 and the body 10 to reinforce the seal when the support 24 is in contact with the body 10.

[0084] A part 14, acting as a stop, limits the spring's travel: the closer this stop is positioned along the piston 8 to the support 24 (and the diaphragm 100), the more the spring is compressed and the greater the pressure of the material (for example, a fluid such as air) that must be applied to open the valve 20. In the representation in Figure 2A, this part 14 is fixed to the piston 8, on the side of the external volume V e of the envelope. In other words, the spring can push back the support 24 (and the membrane it carries) until it is blocked by the body 10.

[0085] The stop 14 is therefore in the internal volume Vi.

[0086] In a preferred embodiment, the body 10 and the support 24 have rotational symmetry about the axis AA'. However, as explained above, other shapes are possible. The piston 8 moves in translation along this axis AA', in this example under the action of the spring 12 and / or a pressure or pressure difference between the inside and outside of the valve or the casing 30. If the support and / or the body has a shape other than circular, it can nevertheless move in translation along an axis AA', preferably substantially perpendicular to the wall 30 in which the valve can be installed.

[0087] The body 10 may include a lower lip lOi which rests on the casing 30 and in the center of which is the axis of movement of the piston 8.

[0088] Spring 12 can be straight or conical (as in Figure 2A). A conical spring can be more compact because its coils are not touching.

[0089] The membrane 100 is held against the support 24 by means of a grid 25 (Figure 2A), which may be provided with a circular reinforcement 25 r , or a ring 25a (figure 2B). A grid 25 allows for better uniform recovery of the force exerted by the air on the membrane and therefore limits the burst pressure (it creates a resistance which will limit the effect of tension on the membrane).

[0090] With such a device, a l èreThe breathing stage can take place through membrane 100. Breathing allows the pressure to equalize between the external environment and the interior of the battery pack. Pressure differences between the outside and inside result from changes in atmospheric pressure, generated, for example, by changes in temperature and / or altitude, etc. Preferably, and as explained above, membrane 100 is waterproof and dustproof to guarantee the integrity of the battery pack containing the electrochemical cells.

[0091] During a 2 èmeIn this step, the valve, or more precisely the support 24 relative to the body 10, opens in the event of internal gas release or a significant increase in pressure and / or temperature inside the battery pack. This opening occurs above a certain pressure level P2 in the volume Vi, which is a function of the surface area over which the force F of the fluid (air / gas) is exerted on the diaphragm 24 with surface area S (P2 = F / S) and the properties of the spring and its state of compression. The force Fr exerted by the spring is Fr = k Lr (k being the spring constant), where Lr is the compression length of the spring. As soon as F > Fr, the valve opens (the fluid force causing the opening is greater than the force exerted by the spring; the force exerted by the spring will increase as the opening occurs due to the compression effect of the spring). For example, such an opening occurs at 40 mbar.A volume of fluid can then escape through the opening or orifice created between body 10 and support 24. As soon as F < Fr, closure occurs: the force of the fluid becomes less than that exerted by the spring; the force exerted by the spring will decrease as closure occurs due to the spring's relaxation effect. No further volume of fluid can then escape because there is no longer an opening or orifice created between body 10 and support 24. A rupture of the membrane 100 can occur during a 3. e step. The aim is then to considerably increase the flow rate through part 10 to limit the increase in pressure and / or temperature in the battery pack, which, for example, can result from a thermal runaway of an electrochemical device contained in the casing 30. The full opening of the piston, obtained during the 2 estep, not being sufficient for this, the membrane 100 will be detached or destroyed at a pressure difference level Pi - P e greater than or equal to Pi (for example, from a minimum of 150 mbar and / or a temperature from 100°C). Between Pi and P2, the opening occurred according to the 2 e step described above; but, during this 3 e step, the opening of the piston towards the external volume V e increases sharply to compensate for the increase in internal pressure Pi and / or internal temperature. At the end of this 3 èmeIn this step, the support 24 tends to close towards the body 1, but it can reopen under the action of the fluid escaping from the casing 30. The example in Figures 2A-2E was given for a breathing and bursting membrane. Such a membrane allows these two functions to be combined: a breathing function, enabling pressure equalization, and a bursting function at a given pressure value, for example, above 150 mbar. During bursting, the bursting membrane can, for example, either detach from its support (for example, because the weld or other fastening method is designed for this purpose) or be destroyed by tearing (for example, at the center of the membrane). The stress exerted by an increase in the battery's volume pressure tends to reach its rupture point. The membrane is thin enough for this. The material of this membrane is, for example, an e-PTFE film or a silicone material.

[0092] Figure 3A illustrates a valve 20a according to the invention, equipped with a membrane having, on the one hand, a zone 2 for breathing and, on the other hand, a zone 4 for bursting, as explained above in relation to Figure IA (alternatively, this could be a membrane of the type explained above in relation to Figures IB-1D). The assembly comprising the body 10 and the support 24 is identical or similar to that already described above in relation to Figures 2A-2E.

[0093] In the illustrated example, the breathing function is provided by the central part 2 of the membrane, while the explosion function is provided by the peripheral part 4. But, as already explained above, it could be the other way around.

[0094] This device works in the same way as the previous one, with a 1 er pressure difference threshold Pi - P e equal to P2 for the opening during the 2 estep and a 2 e pressure difference threshold Pi - P e equal to Pi (Pi > P2) for the explosion, the rupture of the membrane during the 3 e step, the difference being that it is then the peripheral part 4 of the membrane that explodes or is torn.

[0095] The membrane can be held against the support 24 using a grid 25 (as illustrated in Figure 3B) or using a grid 25 and / or a ring 25a (as illustrated in Figure 3C).

[0096] Figure 5 represents an enclosure 30 energy storage device, for example in electrochemical form, for example also comprising a plurality of battery block 110. This enclosure 30 is provided with a valve 20 (or 10a, 20b, 20c) according to the invention.

[0097] A valve or energy storage device according to the invention can be advantageously used in the context of an exothermic incident occurring inside the envelope 30 which can be that of a battery used for example in the field of transport, for example in a vehicle such as a car or truck or airplane, powered by a thermal engine or an electric motor or a hybrid engine.

[0098] In this case, the vehicle may include a passenger compartment, for example, occupied by passengers and / or goods; the valve 20 according to the invention allows gases under pressure and / or overheating to be vented to an area not occupied by passengers and / or goods. Thus, no gas under pressure and / or overheating can escape towards the passenger compartment containing the passengers and / or goods.

[0099] The vehicles shown in Figures 6A-6D, each equipped with an energy storage device 30 according to the present invention, can be:

[0100] - of the type for transporting people and / or goods;

[0101] - and / or of an autonomous type;

[0102] - and / or of motor vehicle type 200 (Figure 6A) and / or construction vehicles, for example of excavator or digger type, or of aircraft type (for example: airplane 210, Figure 6B) or of space type, for example a space station or a satellite; or, alternatively, of the type used in the maritime field, for example a boat 220 (Figure 6C) or a ship or vessel or a submarine, or of the type used in the railway field, for example a locomotive 230 (Figure 6D) or a wagon, or more generally of the type used as an air, land or sea locomotion device.

[0103] Alternatively, not shown, a 2 or 3 wheeled vehicle can be equipped with an energy storage device 30 according to the present invention.

[0104] The invention relates in particular to an application to batteries, especially lithium-ion batteries, which consist of a sealed casing comprising a set of unit cells and most of the time electronic and power components for their interconnection and control.

Claims

DEMANDS 1. Membrane for a breathing valve (100) for an electrochemical energy storage device, comprising: - at least one l ère zone (2, 2a, 2b, 2c), made of felt or a woven material, allowing breathability in both directions through the membrane, at least for a pressure difference between the two sides of the membrane of less than one er threshold (Pi); - at least one 2 ème zone (4, 4a, 4b, 4c), different from the l ère zone (2, 2a, 2b, 2c), designed to burst due to a pressure difference between the two sides of the membrane above the 1 er threshold (Pi).

2. Membrane according to claim 1, the 2 zones being juxtaposed.

3. Membrane according to claim 1, one of the 2 zones surrounding the other zone.

4. Membrane according to any one of claims 1 to 3, the l ère zone and the 2 èmeareas being fixed to each other, for example by welding.

5. Membrane according to any one of claims 1 to 3, the l ère zone and the 2 ème areas being fixed or assembled on or with the same support (3), for example a film or an adhesive layer.

6. Membrane according to any one of claims 1 to 5, wherein the 2 ème zone (4, 4a, 4b, 4c) forms a thin layer or a multilayer and / or is made of a plastic or metallic material, for example a polypropylene or polyethylene type material, or e-PTFE.

7. Membrane according to any one of claims 1 to 5, wherein the 2 ème zone (4, 4a, 4b, 4c) is made of natural or synthetic fiber(s), or hemp, or coconut.

8. Membrane according to any one of claims 1 to 7, wherein the ère zone (2, 2a, 2b, 2c), is made of a porous material, for example e-PTFE or perforated silicone or fibrous material.

9. Membrane according to any one of claims 1 to 8, wherein the constituent material has at least partly hydrophobic and / or oleophobic properties and / or is provided with a hydrophobic and / or oleophobic coating and / or the membrane comprising at least one waterproof part.

10. Membrane according to any one of claims 1 to 9, wherein the ère zone (2, 2a, 2b, 2c), has a flow rate between 0.2 and 3.5 l / min / cm 2 .

11. Valve (20, 20a, 20b) for an electrochemical energy storage device, this device comprising a casing (30), this valve itself comprising: - a valve body (10); - a l ère membrane (2, 4, 100, 100a), according to any one of claims 1 to 10, capable of bursting at least for a pressure difference between the 2 sides of the membrane greater than a threshold (Pi) and means (24) forming at least a 1 er support of the said l ère membrane (2, 4, 100, 100a); - means (8, 12) maintaining the valve in a closed state for a pressure difference between the 2 sides of the diaphragm less than (P2) and allowing the valve to be opened, by opening or moving the first support (24) relative to the body (10), for a pressure between (Pi) and (P2), Pi > P2.

12. Valve according to claim 11, the l ère membrane (2, 4, 100, 100a) being held against the support (24) by means of holding means (25, 25a). 19 13. Valve according to claim 11 or 12, the l ère membrane (2, 4, 100, 100a) being waterproof.

14. Valve according to claim 11 or 13, the l ère membrane also allowing at least one respiration by circulation of fluid through it.

15. Valve according to any one of claims 11 to 14, the means (24) forming support being disposed at one end of a piston (8), which passes through the valve body.

16. Valve according to any one of claims 11 to 15, the means (8, 12) maintaining the valve in a closed state for a pressure difference less than (P2) and allowing opening of the valve for a pressure between (Pi) and (P2) comprising at least one spring (12), each bearing against a fixed part of the body (10) of the valve and a movable part, (14) connected to the support (24).

17. Valve according to the preceding claim, the moving part (24) linked to the support (24) comprising a stop (14).

18. Valve according to claim 16 or 17, the spring (12) being a straight or spiral spring.

19. Energy storage enclosure in electrochemical form, for example of battery type, comprising an envelope (30) containing one or more energy storage elements (110), this envelope being provided with at least one valve (20, 20a, 20b, 20c) according to any one of claims 11 to 18.

20. Vehicle, comprising a passenger compartment and / or a storage area, an engine, and at least one energy storage enclosure according to claim 19.

21. Vehicle according to claim 20, this vehicle being: 20 - of the type for transporting people and / or goods; - and / or of an autonomous type; - and / or type of motor vehicle and / or construction vehicle, for example of excavator or backhoe type, or of aircraft or space type, or of the type used in the maritime field, for example boat or ship or craft or submarine, or of the type used in the railway field, for example locomotive or wagon.

22. Vehicle according to claim 20 or 21, this vehicle being 2-wheeled or 3-wheeled.

23. A method for operating a valve (20, 20a, 20b, 20c) of an electrochemical energy storage vessel according to claim 19, wherein: a) - the valve is held in a closed state for a pressure difference between the inside of the vessel and the outside (Pi - P e ) of the lower enclosure at (P2); b) - the valve is in an open state for said pressure difference between (Pi) and (P2), Pi > P2; c) - the diaphragm bursts for said pressure difference greater than (Pi).

24. A method according to the preceding claim, wherein there is fluid exchange between the inside and outside of the enclosure through the l ère area of ​​the membrane at least during step a).

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