Safety valve system enabling injection of liquid

Abstract

The invention relates to a safety valve (100) for extinguishing thermal runaway or fire in a device for storing energy in electrochemical form, this device comprising a casing (30), the valve itself comprising: - a valve body (1), provided with a valve shutter (5) and a valve-shutter support (4), the valve shutter being able to come into the closed position, bearing against a first face of the support; - the support (4) comprising at least one orifice (41, 42) for allowing a flow of a material to circulate when the valve shutter (5) is in the open position, and means (12, 12') for: * keeping the valve shutter in the open position for a pressure, exerted from the first face of the support, below a 2nd threshold which is lower than a 1st threshold; * bringing the valve shutter into the closed position for a pressure, exerted from the first face of the support, above the 2nd threshold but below the 1st threshold; * allowing the valve to open for a pressure, exerted from the second face of the support, above the 1st threshold; - means (20) for connecting a duct for injecting a material into the valve, from the second face of the support towards its first face, - and a membrane (35) attached to, or against, the support (4).

Description

[0001] DESCRIPTION

[0002] Title: SAFETY VALVE SYSTEM ALLOWING LIQUID INJECTION

[0003] TECHNICAL FIELD AND PRIOR 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 related to batteries, in particular lithium-ion batteries, which consist of a sealed envelope comprising a set of unit cells and most of the time electronic and power components for their interconnection and control. Today, essential battery technologies are seeing their energy density increase and their architecture evolve.

[0006] In the event of a major exothermic phenomenon occurring in the battery, for example thermal runaway or even a fire, the battery will release a large quantity of energy and gas, which requires the opening or rupture of a dedicated system such as a degassing valve.

[0007] Each cell in the battery will potentially see its temperature increase when one or more cells experience thermal runaway. This will lead to a complete spread of the fire inside the pack or, more generally, the casing.

[0008] Once installed in the battery volume, the fire risks spreading to the battery environment and then to the entire vehicle equipped with the battery. It is possible, thanks to evacuation systems, to limit the thermal spread and therefore the intensity of the battery fire.

[0009] However, these evacuation systems may not be sufficient to limit the spread of the fire and confine it to the battery and the vehicle. If emergency services must intervene to try to stop the thermal runaway or fire, it appears useful to have access to the battery so that it can be cooled and the fire extinguished.

[0010] Unfortunately, most battery packs today are completely sealed and cannot be easily cooled. This means that, after a fire starts, there are many cases of fires catching again.

[0011] To enable effective extinction, which corresponds to flooding, preferably complete, of the battery with an extinguishing fluid, two solutions appear:

[0012] - either placing the battery in a container filled with water from the vehicle;

[0013] - either the perforation of the battery casing, irreversibly, which allows the wall of the battery pack to pass through.

[0014] These two measures are not easy to implement and require a specific architecture.

[0015] A problem is therefore to allow simple and rapid access directly to the battery volume in order to drown it. Preferably, we also want to allow a non-return valve to prevent smoke from being released through this same access.

[0016] STATEMENT OF THE INVENTION

[0017] The invention firstly concerns a valve, or safety valve, this valve comprising:

[0018] - a valve body, provided with a valve and a valve support, the valve being able to come into the closed position, resting opposite a first face of the support;

[0019] - the support comprising at least one orifice to allow a flow of liquid to circulate when the valve is in the open position (i.e. it is not in the support position facing the support);

[0020] - means for maintaining the valve in the closed position opposite the first face of the support and for allowing the valve to open for a pressure, exerted from the second face of the support, greater than a l ère threshold value;

[0021] - means for connecting a channel for injecting a material, for example a fluid, for example water, into the casing. A valve according to the invention is particularly well suited for extinguishing a thermal runaway or a fire in an energy storage device, for example in electrochemical form, for example a lithium-ion battery, this device comprising a casing, said valve being arranged in an orifice of this casing.

[0022] The invention therefore relates in particular to a safety valve for extinguishing a thermal runaway or a fire in an electrochemical energy storage device, this device comprising a casing, this valve itself comprising:

[0023] - a valve body, provided with a valve and a valve support, the valve being able to come into the closed position, resting opposite a first face of the support;

[0024] - the support comprising at least one orifice to allow a flow of material to circulate when the valve is in the open position;

[0025] - means for maintaining the valve in the closed position opposite the first face of the support and for allowing the valve to open for a pressure, exerted from the second face of the support, greater than 1 er threshold ;

[0026] - means for connecting a channel for injecting a material into the valve, from the second face of the support to its first face.

[0027] The valve-forming means allow:

[0028] * to allow, in the open position, the circulation of a material or fluid from the outside of the valve to the inside of it, when a pressure of this material or fluid is greater than the l ère threshold value;

[0029] * and possibly to close, in a second position, called the closed position, any circulation of material or fluid between the inside and the outside of the valve when the pressure of the material or fluid is lower than said l ère threshold pressure. Whatever the implementation concerned:

[0030] - the pressure of 1 er threshold may be at least equal to 1 bar, for example between 1 bar and 5 bars;

[0031] - and / or the valve-forming means may be arranged at one end of a piston, which passes through the support; - and / or the means for forcing the valve-forming means into the closed position comprise at least one spring, for example one or more straight or spiral springs, each bearing against a fixed part of the valve body and a movable part, linked to the valve; for example, the movable part linked to the valve comprises a stop.

[0032] According to one embodiment, a valve according to the invention further comprises means for: -keeping the flap in the open position for a pressure, exerted from the first face of the support, less than a 2 ème threshold which is less than 1 er threshold;

[0033] - to bring the valve into the closed position for a pressure, exerted from the first face of the support, greater than 2 ème threshold but less than 1 er threshold.

[0034] The various thresholds can be set a priori, the person skilled in the art knowing well what pressures are involved during thermal runaway or a fire in an electrochemical energy storage enclosure.

[0035] Such a valve may further comprise a membrane fixed to, or against, the support; for example, this membrane has a burst pressure of less than 1 er threshold.

[0036] The invention also relates to an enclosure or a device for storing energy in electrochemical form, for example a battery, for example a lithium-ion battery, comprising an envelope containing one or more energy storage elements, for example one or more battery packs, this envelope being provided with a valve according to the invention.

[0037] Such an enclosure may further comprise an evacuation valve which allows the internal atmosphere to escape to the external atmosphere of the enclosure, in particular when the valve according to the invention is in its closed position, for example when a thermodynamic parameter is greater than a limit value, for example when the pressure and / or the temperature internal to the enclosure is greater than a limit pressure and / or temperature, the valve according to the invention then being able to be or being in the closed position.

[0038] The invention also relates to a vehicle, comprising a passenger compartment and / or a storage area, an engine, and at least one energy storage enclosure according to the invention. Such a vehicle is, for example, a car or a truck or an airplane or a construction machine, for example an excavator or a digger, the engine being able to be a thermal engine or an electric motor or a hybrid engine.

[0039] Such a vehicle can be for example:

[0040] - of the type for transporting people and / or goods;

[0041] - and / or autonomous type;

[0042] - and / or type of motor vehicle and / or construction vehicles, for example excavator or digger type, or aircraft type or space type, or of the type used in the maritime field, for example boat or ship or boat or submarine, or of the type used in the railway field, for example locomotive or wagon, more generally of the type used as an air, land or sea locomotion machine.

[0043] The invention also relates to a method of operating or controlling and / or activating a valve or an energy storage enclosure according to the invention.

[0044] In particular, the invention also relates to a method for controlling a safety valve for extinguishing a thermal runaway or a fire in an electrochemical energy storage device according to the invention, a method in which water or, more generally, a fluid or a material, for example a foam, is injected from the 2 e side of the support towards the inside of the enclosure, by means, at a pressure greater than 1 er threshold, thus moving the valve from a closed position to an open position.

[0045] The injection of fluid or a material, for example foam, makes it possible to isolate the parts from each other and / or to cool the system very effectively.

[0046] In such a method, the valve may be previously held in the closed position under the action of hot gases inside the envelope, these hot gases being able, for example, to result from thermal runaway of a fire inside the envelope.

[0047] In a method or device according to the invention, the fluid is intended to extinguish a fire or to reduce, in particular to control, thermal runaway; it is for example a fire-retardant fluid or an extinguishing fluid, for example water or a dielectric fluid, for example mineral oil, or a foam or CO2, the latter having a sudden expansion at the outlet and allowing cooling at the same time as it ensures a sudden replacement of oxygen.

[0048] BRIEF DESCRIPTION OF THE DRAWINGS

[0049] [Fig. 1] represents an exemplary embodiment of a breathing valve according to the invention in the closed position;

[0050] [Fig. 2] shows a connection tip connected to a valve according to the invention;

[0051] [Fig. 3] and [Fig. 5] show a valve according to the invention, seen from the outside.

[0052] [Fig. 4] represents a sectional view of a valve according to the invention and its fluid injection nozzle.

[0053] [Fig. 6] represents an exemplary embodiment of a variant of a valve according to the invention in the normally open position;

[0054] [Fig. 7] represents an enclosure of an energy storage device comprising a valve according to the invention as well as an evacuation valve.

[0055] [Fig. 8A] - [Fig. 8D] 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 an evacuation valve.

[0056] DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0057] Figures 1 to 3 represent aspects of an exemplary embodiment of a valve 100 according to the invention.

[0058] It comprises a fixed body 1, shown here placed in a dedicated orifice of the casing 30 of an energy storage device in electrochemical form, for example a battery pack. This body 1 is fixed for example using means 11, which can be attached, welded or crimped; these are for example screws or rivets. These means 11 are preferably sealed or provided with means (one or more seal(s)) which make it possible to ensure their sealing.

[0059] The interior volume of this envelope is designated by the reference Vi, its interior volume by the reference V e A seal 29 can ensure a seal between the body 1 and the casing 30.

[0060] In this example, this body has a symmetry of revolution around an axis AA'. But other shapes can be produced, but compatible with an injection of a material, for example a fluid, for example still water, by the valve, preferably adapted to the connection of a fire hose. The body 1 has an orifice 2 in which a support 4 of valve 5 is positioned. This support is between:

[0061] - a l ère mainly flat face i (this face is turned towards the inside of the enclosure when the valve is mounted on the latter), against, or opposite, which the valve 5 can be applied;

[0062] - a 2 ème mainly flat face 4 e (this face faces the outside of the enclosure when the valve is mounted on the latter).

[0063] The support 4 is provided with or crossed by one or more orifices 4i, 4?... (see also figure 3) through which the material, for example a fluid, for example still water, will be able to flow, in a direction going from the outside of the valve, or the 2 e side 4 e from support 4, towards the inside of the valve, or towards the ère face 4i of the support 4 (the direction of injection of the material, for example a fluid, for example still water, is represented by an arrow 27). It can also be provided with a central orifice 4o through which a piston (or rod or bar) 8, at one end of which the valve 5 is fixed, will be able to move.

[0064] The support 4 may comprise or be extended by a central cylindrical part 6, which extends towards the outside of the casing and inside which the piston 8 will be able to slide. In the form shown, the valve is of circular shape, adapted to that of the valve shown. However, if the latter has another shape, then the valve has a corresponding shape.

[0065] At least one spring 12 holds the valve 5 in the normally closed position against the support 4, thus blocking any circulation of atmosphere or liquid or fluid or material between the interior volume Vi and the exterior volume V e of the envelope, in one direction or another.

[0066] A single spring is shown in figure 1, but there can also be 2 springs which both press against the support 4. 2 springs allow a longer stroke of the piston 8. They allow the system to be compacted, the coil diameters to be reduced and the stroke to be maximized (in particular in the case of contiguous coils, less quickly).

[0067] A lateral seal 15 may be arranged between the periphery of the support 4 and the valve 5 to reinforce the seal when the latter is resting against the support 4 or opposite the latter.

[0068] Furthermore, a volume 25 can be provided between the support 4 and the valve 5 when the latter is in the closed position, resting against the support 4 or opposite the latter. A part 14 forming a stop limits the travel of the spring: the closer this stop is positioned, along the piston 8, to the valve 5, the more the spring(s) is / are compressed and the greater the pressure of the material (for example fluid, for example water), which will have to be applied to open the valve will be. In the representation of figures 1 and 2, this part 14 is fixed to the body 1, on the side of the external volume V e of the envelope. In other words, the spring(s) can push the valve back until it is blocked by the support 4, in a position in which no material or fluid can circulate between the external volume V e and the interior volume Vi of the envelope.

[0069] Preferably, the valve 5 is therefore in direct contact with the interior volume Vi and the stop 14 with the exterior volume V e . Thus, the pressure difference exerted on the valve corresponds to the force exerted by the spring on the stop 14 and on the support 4. When the fluid pressure applied on the side of the stop 14 exceeds a l ère threshold value, the valve is moved to its open position.

[0070] According to a preferred embodiment, the valve 5 as well as the piston 8 have a symmetry of revolution around the axis AA'. But, as already explained above, other shapes can be produced. 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 a pressure difference between the inside and the outside of the valve or the casing 30. If the valve and / or the piston 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. The support 4 can be extended laterally by a skirt 24 which extends parallel to the piston 8 and which, with the support 4, delimits an interior volume or space 16 of the valve, at the center of which is the axis of movement of the piston 8.

[0071] On the side of the volume or the interior space 16 of the valve, a tip or a connection or interface means 20 can extend the skirt 24, in order to connect a water injection tube thereto, for example a fire hose. This tip 20 is shown more clearly in figures 2 and 4 (in which the valve 5 is in the closed position against the support 4).

[0072] The spring 12 can be straight or conical. A conical spring can be more compact, because its coils are not joined.

[0073] Figure 3 shows the valve 100 mounted on a casing 30; the stop 14 and the orifices 4i, 4?... of the support 4 are clearly visible. This figure 3 does not show the end piece 20. Figure 4 shows a sectional view of the valve 100 and the end piece 20, in a position in which the spring 12 forces the flap 5 into the closed position against the support 4. The direction of injection of a material or a fluid is shown by an arrow 27.

[0074] In a l ère operating phase, the pressure difference between the interior Vi and the exterior V e of the valve or casing does not exceed the l ère threshold value, for example between 1 and 5 bars, allowing the spring 12 to be compressed towards the support 4: the valve remains in abutment against the latter and no material or fluid can then circulate between the inside and the outside of the valve or the casing

[0075] In a 2 èmeoperating phase, an overpressure inside the valve or the casing occurs, due for example to thermal runaway (for example due to a rapid increase in temperature and / or an additional volume of combustion gas causing the overpressure). The valve remains closed, not allowing the escape of hot gases, for example from cell combustion. These may possibly escape through other orifices or valves in the enclosure, dedicated to overpressure (as explained later in connection with Figure 7). According to a 3 ème operating phase, during an intervention, for example by a firefighter, to render the battery inoperable or in the event of a battery fire, water or more generally a fireproof (or extinguishing) material or fluid is introduced at a pressure greater than the èrethreshold value that allows the valve 5 to be pushed back. For example, a fire hose is placed, connected to the nozzle 20 or to the battery valve so that when the flow in the hose is triggered, the valve can open under the effect of the pressure. The valve will then allow the material (or fluid, for example water) to fill the volume of the battery and flood the pack.

[0076] According to a 4 ème operating phase, after the injection of the material or fluid, the valve closes under the action of spring 12. Hot gases can therefore not escape from the casing or the battery. The valve can continue to operate and is not destroyed.

[0077] As a variant, shown schematically in Figure 6, another valve 100' according to the invention comprises a filtering membrane 35, for example positioned against the support 4, the valve 5 being in the normally open position (unlike the embodiment previously explained), the valve then ensuring breathing between the interior and the exterior, and being closed if an overpressure, for example linked to combustion gases, occurs in the volume inside the casing 30. To this end, a 2 eme spring 12' is arranged between the valve 5 and the support 4 and makes it possible to keep the valve at a distance from the latter under normal operating conditions, that is to say when the pressure is approximately balanced between the interior Vi and exterior V volumes eof the casing 30 The springs 12, 12' allow the valve to be left open as long as the internal pressure in the battery pack is lower than the pressure of the external environment, for example 50 mbar lower than the external pressure, more generally lower than the external pressure by a value for example between 40 mbar and 500 mbar. The membrane has, for its part, a breaking limit of the order of a few hundred mbars, for example between 200 mbar and 500 mbar, and will be broken as soon as a material or a fluid is introduced from the outside, at a pressure for example greater than 1 bar. In a l ère operating phase, the pressure difference between the interior Vi and the exterior V e of the valve or the casing is balanced, the valve is open (position shown in figure 6), that is to say that an atmosphere can circulate through the membrane 35, for example from the outside V einwards Vi (the valve then functioning as a breathing valve).

[0078] In a 2 ème operating phase, an overpressure inside the valve or casing occurs, due for example to thermal runaway (e.g. due to a rapid temperature increase and / or an additional volume of combustion gas causing the overpressure). When this overpressure exceeds a 2 e threshold value, which is less than the l ère threshold value, the valve moves to the closed position (the spring 12' is compressed), preventing the escape of hot gases, for example from cell combustion. These may possibly escape through other orifices or valves in the enclosure, dedicated to overpressure.

[0079] According to a 3 èmeoperating phase, during an intervention, for example by a firefighter, to render the battery inoperable or in the event of a battery fire, water, or more generally a fluid or material, is introduced at a pressure greater than the ère threshold value. This l èrethreshold value is higher than the pressure present in the internal volume Vi, the pressure of the fluid or material introduced therefore causes the membrane to rupture (the rupture pressure of which is for example between 200 mbar and 500 mbar, for example still approximately equal to 400 mbar), it allows the valve 5 to be pushed back which results in the flooding of the battery. For example, a fire hose is put in place, connected to the conduit or to the battery valve so that when the flow of material or fluid is triggered in the hose, the valve can open under the effect of the pressure. The valve will then allow the material or fluid (for example water) to fill the volume of the battery and flood the pack. Under the effect of the flow of material or fluid, the membrane 35 will most often be destroyed. And, after the injection of the material or fluid, the valve does not close, because it is normally open.

[0080] Figure 7 represents an envelope 30 energy storage device, for example in electrochemical form, for example also comprising a plurality of battery blocks 110. This envelope 30 is provided with a valve 100 (or 100') according to the invention and can also be provided with a valve or a discharge or evacuation valve 17 in the event of overpressure and / or internal heating: the overpressure and / or overheated gases in the envelope escape through this valve 17, while the valve 100, 100' operates as explained above.

[0081] A valve or an energy storage device according to the invention can be used advantageously in the context of an exothermic incident occurring inside the casing which can be that of a battery used for example in the field of transport, for example again in an automobile or a truck or an airplane, powered by a thermal engine or an electric motor or a hybrid engine.

[0082] In this case, the atmosphere outside the valve 100 (or 100') may be a passenger compartment of the vehicle (as illustrated in FIG. 8A), for example occupied by passengers and / or goods, while the evacuation valve 17 allows overpressure and / or overheated gases to be evacuated into an area not occupied by the passengers and / or goods. Thus, no overpressure and / or overheated gases will be able to escape towards the passenger compartment in which the passengers and / or goods are located. The valve 100 (or 100') allows intervention to extinguish combustion internal to the envelope.

[0083] The vehicles shown in Figures 8A - 8D, each equipped with an energy storage device 30 according to the present invention, can be:

[0084] - of the type for transporting people and / or goods;

[0085] - and / or autonomous type;

[0086] - and / or of the type of motor vehicle 200 (figure 8A) and / or construction vehicles, for example of the excavator or digger type, or of the aircraft type (for example: airplane 210, figure 8B) or of the 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 8C) or a ship or a boat or a submarine, or of the type used in the railway field, for example a locomotive 230 (figure 8D) or a wagon, or more generally of the type used as an air or land or sea locomotion machine. The invention relates in particular to an application to batteries, in particular lithium-ion batteries, which are made up of a sealed envelope comprising a set of unit cells and most of the time electronic and power components for their interconnection and control.

Claims

CLAIMS 1. Safety valve (100) for extinguishing a thermal runaway or a fire in an electrochemical energy storage device, this device comprising a casing (30), this valve itself comprising: - a valve body (1), provided with a valve (5) and a valve support (4), the valve being able to come into the closed position, bearing opposite a first face of the support; - the support (4) comprising at least one orifice (41, 4?) to allow a flow of a material to circulate when the valve (5) is in the open position of the means (12, 12') for: * keep the valve in the open position for a pressure, exerted from the first face of the support, less than 2 ème threshold which is less than 1 er threshold; * bring the valve into the closed position for a pressure, exerted from the first face of the support, greater than 2 èmethreshold but less than 1 er threshold ; * let the valve open for a pressure, exerted from the second face of the support, greater than 1 er threshold ; - means (20) for connecting a channel for injecting a material into the valve, from the second face of the support to its first face, - and a membrane (35) fixed to, or against, the support (4).

2. Valve according to claim 1, the pressure of 1 er threshold being at least equal to 1 bar, for example between 1 bar and 5 bars.

3. Valve according to one of claims 1 or 2, the valve-forming means (5) being arranged at one end of a piston (8), which passes through the support (4).

4. Valve according to one of claims 1 to 3, the means (12) for forcing the means (5) forming a valve in the closed position comprising at least one spring, each bearing against a fixed part (4) of the body of the valve and a movable part (14) linked to the valve (5).

5. Valve according to the preceding claim, the movable part (14) linked to the flap comprising a stop.

6. Valve according to claim 4 or 5, the spring(s) (12) being one or more straight or spiral spring(s).

7. Valve according to one of claims 1 to 6, the membrane (35) having a burst pressure lower than 1 er threshold.

8. Enclosure for storing energy in electrochemical form, for example of the battery type, comprising an envelope (30) containing one or more energy storage elements (110), this envelope being provided with at least one safety valve (100, 100') according to one of claims 1 to 7.

9. Storage enclosure according to claim 8, further comprising at least one evacuation valve (17) which allows an escape of the interior atmosphere to the exterior atmosphere of the envelope (30) when a thermodynamic parameter is greater than a limit value.

10. Vehicle, comprising a passenger compartment and / or a storage area, an engine, and at least one energy storage enclosure according to one of claims 8 to 9.

11. Vehicle according to claim 10, this vehicle being: - of the type for transporting people and / or goods; - and / or autonomous type; - and / or type of motor vehicle and / or construction vehicles, for example excavator or digger type, or aircraft type or space type, or of the type used in the maritime field, for example boat or ship or boat or submarine, or of the type used in the railway field, for example locomotive or wagon.

12. Method for controlling a safety valve (100, 100') for extinguishing a thermal runaway or a fire in an electrochemical energy storage enclosure according to claim 9 or 9, method in which a material, for example a fluid, is injected from the 2 e side of the support (4) towards the inside of the enclosure, by the means (20), at a pressure greater than 1 er threshold, thus moving the valve (5) from a closed position to an open position.

13. Method according to the preceding claim, in which the valve (5) is previously held in the closed position under the action of hot gases inside the casing (30).

14. Method according to claim 12 or 13, the material being capable or intended to extinguish a fire or to control thermal runaway.

15. A method according to claim 14, the material being an extinguishing fluid comprising water or a dielectric fluid, for example mineral oil or foam or inert gas, or foam or CO2.

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