Method and apparatus for extinguishing a fire on an object

Abstract

The invention relates to a method for extinguishing a fire on an object, wherein the method comprises the following steps: - providing a container containing a solid granulate of loose solid particles, - generating a fluidized bed within the container filled with the solid granulate by introducing a gaseous fluid into the solid granulate such that the burning object at least partially sinks into the fluidized bed, - wherein the object is introduced into the container before or after the generation of the fluidized bed, and - ceasing the introduction of the gaseous fluid into the container when the burning object has at least partially sunk into the fluidized bed in order to cease generating the fluidized bed and to embed the sunken object at least partially in the solid granulate.

Description

The invention relates to a method for extinguishing a fire on an object. The invention also relates to a device for this purpose.Extinguishing a fire is more or less difficult depending on the material burning. In particular when a plurality of different chemical elements and compounds are present, special measures are required for extinguishing a fire in such a material mixture in order to reliably and completely extinguish a fire and in the process to avoid personal and object damage to the greatest possible extent.Recently, the number of lithium ion batteries (particularly rechargeable batteries) is steadily increasing because there are more and more mobile devices that people use their daily life. Owing to their high energy density and the largely absent memory effect, such lithium-ion batteries are used in a large number of products, such as, for example, mobile telephones (smartphone, handy phone), earphones, laptops, tools, electric scooters, electric bicycles and meanwhile also in large numbers in electric cars.Such lithium-ion batteries, however, have the disadvantage that their chemical compositions partially react extremely vigorously with many substances and, in addition, tend to overheat, so that such batteries can also quickly get in fire. Therefore, such lithium-ion batteries are generally also to be classified as hazardous material.At a temperature above 69° C., the solid electrolyte interface (interface between the anode and electrolyte) begins to decompose, followed by exothermic reactions between anode and electrolyte and anode material and binder. This is followed by the separator melt, the electrolyte decomposition and reactions between cathode material and electrolyte. More and more heat is released in all these reactions. A chain reaction can occur if the cell is not actively cooled. Here, thermal runaway (england is also used. Thermal Runaway).During thermal cycling in a lithium ion battery, the electrolyte and separator can contribute significantly to heat release in the presence of oxygen through their ignition and combustion properties. This effect also acts on the adjacent cells in a battery which consists of a plurality of cells. Therefore, a whole battery consisting of a plurality of individual cells (lithium-ion battery cell) may be destroyed.Triggers for such thermal runaway are typically divided into four categories. The first category is an internal short circuit. An internal short circuit arises as a result of the failure of the separator, as a result of which a short circuit between the electrodes and therefore a thermal runaway occurs. This may occur due to a misuse condition or as a result of a manufacturing error. The second category is improper use (overcharge, deep discharge). Overcharging or deep discharging to voltages beyond the manufacturer's specified voltage limits can result in lithium plating or dendritic formation at the anode. Over time, this may penetrate the separator, resulting in a short circuit between the electrodes and thermal runaway. The third category is a thermal overload in which a cell temperature from 70° C. can directly lead to a thermal runaway. The mechanical damage (entry of objects, clamping or bending of the cell) as a fourth category can ultimately lead to a short circuit between the electrodes and thus to a thermal runaway.If, as a result of one of the above-mentioned cases, the cell passes thermally and thus the cell or the battery burns, this cannot be completely thickened by excluding oxygen, since the cathodes decompose at high temperatures and in the process emit oxygen. However, the fires in which the cathode is not yet decomposed may be first embrittled, whereby the thermal runaway may be delayed.A further risk arises due to the gases which form on decomposition of the electrolyte. This produces lower hydrocarbons, carbon monoxide, hydrogen fluoride and hydrogen, which can form an explosive mixture with oxygen.In order to completely extinguish the fire of a cell or battery, the flames must first be ignited, the explosive environment prevented and the cell or battery must be cooled. Cooling is especially important in batteries having many individual cells, since thermal runaway in adjacent cells can thus be prevented.In order to extinguish such fires, there are various extinguishing agents such as (water, dry powder, CO 2 and foam). The use of water as extinguishing agent is recommended since the cooling of the cells has a particularly high significance.For example, DE 20 2020 102 574 U1 discloses a extinguishing lance for extinguishing burning electrical devices in order to introduce the extinguishing agent at the correct location even in large batteries in which the cells are arranged in a housing.After the battery has been deleted, however, repeated lighting can occur again and again. This may be due to lack of cooling after the fire test or to renewed internal short circuits in the battery due to damage by the fire or the fire test. The stored energy remaining in the cells can also lead to thermal runaway again and again due to the short circuits.DE 10 2016 211 854 B3 discloses a container for recovering a damaged electric current. The container has a container bottom and a plurality of side walls defining a receiving area for the vehicle. If the vehicle is located in the receiving region, a coolant or extinguishing agent can be filled into the receiving region in order to extinguish the burning vehicle. A disadvantage here is that the travel property of the container transporter with container and the vehicle and the coolant or extinguishing agent is significantly impaired. In order to avoid this, the extinguishing agent could only be filled to a low height or be completely drained off during the journey. This allows flame to be again generated during transport, since neither oxygen sealing nor cooling is provided.It is therefore the object of the present invention to specify an improved method and an improved device for extinguishing a fire on an object, in particular on an electrical object, which in particular easily and reliably permanently extinguishes a fire on a lithium-ion battery.The object is achieved according to the invention by the method according to claim 1 and the apparatus according to claim 8. Advantageous embodiments of the invention are then found in the corresponding dependent claims.According to claim 1, a method for extinguishing a fire on an object is proposed, the method comprising the following steps:providing a container containing solid granules of loose solid particles,creating a fluidized bed within the container filled with the solid granules by introducing a gaseous fluid into the solid granules such that the object which has burned at least partially sinks into the fluidized bed,wherein the object is introduced into the container before or after the creation of the fluidized bed, andterminating the introduction of the gaseous fluid into the container when the fired article has at least partially collapsed into the fluidized bed to terminate the creating of the fluidized bed and at least partially embed the collapsed article in the solid granules.According to the invention, it is proposed that in a container in which solid granules of loose solid particles are contained, a fluidized bed (also called fluidized bed) is produced by the introduction or blowing of a gaseous fluid, in which the object which has been burned at least partially, preferably completely, dips. After the object has at least partially entered this fluidized bed, the introduction of the gaseous fluid is ended, whereby the fluidized bed of the solid granulate coincides with its solid particles and embeds the object which has been burned in the solid granulate. In this case, the necessary oxygen is removed from the fire, whereby the risk of reflammation is reduced.A fluidized bed is a physical phenomenon that occurs when a solid particulate matter (usually in a container) finds the proper conditions so that it behaves as a liquid. The resulting fluidized bed medium has broadly characteristics and characteristics of a normal liquid, e.g., the ability to freely flow under gravity. Also, depending on prevailing conditions, it is sometimes observed that light objects float on this fluidized bed while heavy objects enter.By creating a fluidized bed in a container, a possibility is created of quickly burying a burning object under the solid granules. The fluid throughput and the arrangement of the gas outlets should be selected such that objects sink as quickly as possible. As soon as the object has fallen into the fluidized bed, the fluid supply is shut off and the solid granules are again solid.The object can be introduced into the fluidized bed in a burning manner, for example with the aid of a crane (in the case of large objects, such as cars) or with the aid of tongs. However, the object can also be in the non-burning state on the surface formed by the solid solid granules, wherein the fluidized bed is only produced when the object begins to burn. As a result, a type of emergency system can be set up in order to be able to optimally quench easily flammable or rapidly combustible objects.The object can be an electronic device that contains in particular a battery, for example a lithium ion battery.According to one embodiment, it is provided that the solid granules are sand. However, other materials which are used for extinguishing fire are also conceivable.According to one embodiment, it is provided that the gaseous fluid is air or an inert gas or a gaseous fluid which contains at least 50% CO 2, preferably at least 70% CO 2, particularly preferably at least 90% CO 2.The gaseous fluid can be selected in particular such that it contains no oxygen or only a very small proportion of oxygen (below one percent). As a result, the fire can be first embroidered in the widest sense under the solid granulate.According to one embodiment, it is provided that after the production of the fluidized bed has ended by ending the introduction of the gaseous fluid, a liquid extinguishing agent is introduced into the solid granules embedding the sunk object.By introducing extinguishing agent, for example water, the solid granules, in particular the lowermost layer, can now additionally be watered. This additionally achieves cooling, which is advantageous in particular when lithium-ion batteries are burned and at the same time promotes rapid nitriding of the flames.According to one embodiment, it is provided that at least after the production of the fluidized bed is ended by ending the introduction of the gaseous fluid, the container and / or the solid granules embedding the sunk object are cooled by a coolant and / or a cooling device.In particular when using an article in which a lithium ion battery has ignited, it is advantageous that the container and / or the solid granulate is actively cooled, so as to interrupt the above-described chain reaction in the event of the firing of such battery cells. The cooling by means of the cooling device is effected in particular in such a way that heat is actively extracted from the container interior, in which the solid granules and the object which has been burned are located.According to one embodiment, it is provided that the non-burning object is provided on the solid granules in the container, wherein a fire is detected on the object by means of a detection device and the generation and termination of the fluidized bed is triggered after the detection of the fire.In this case, the method is only carried out when the outbreak of a fire has actually been detected on the object. The object lies on the surface of the solid solid granules in the non-burning state. If a fire is now detected, the gaseous fluid is blown in, whereby the fluidized bed is formed and the object sinks into the fluidized bed. The injection of the gaseous fluid is then ended, as a result of which the fluidized bed collapses and the solid pellets solidify again. The object thus burned is thus automatically embedded in the solid granulate and the fire extinguished. When detecting the fire, the extinguishing method according to the invention is thus carried out in that the fluidized bed is first produced by introducing the gaseous fluid and the introduction of the gaseous fluid is ended after the object which has reached the fire has sinking in.In this case, it can be advantageous if, when a fire is detected, a charging process is ended which charges a lithium-ion battery of the object.The object is also achieved with the device according to claim 8 for extinguishing a fire on an object, comprisinga container filled with solid granules of loose solid particles,a fluid introduction device which is configured for introducing a gaseous fluid into the solid granules for producing a fluidized bed within the container filled with the solid granules, anda control device configured to generate a switch-on signal for the fluid introduction device in order to start the generation of the fluidized bed when the object which has been burned is introduced into the container, and to generate a switch-off signal for the fluid introduction device in order to end the generation of the fluidized bed when the object which has been burned has at least partially entered the fluidized bed in order to embed the object which has been burned at least partially in the solid granules.The device is configured to execute the method described above.According to one embodiment, it is provided that the container has an air-permeable base which is provided at the base of the container and interacts with the fluid introduction device in such a way that the gaseous fluid is introduced through the air-permeable base into the solid granules for producing the fluidized bed.Such an air-permeable base can be realized, for example, with the aid of an air-permeable membrane.According to one embodiment, it is provided that the apparatus has a detection apparatus which is configured to detect a fire on the object located in the container, wherein the control device is configured to generate the switch-on signal as a function of the detection of the fire.In this case, it can be provided that the control device is furthermore configured to interrupt a charging process of the object located in the container as a function of the detection of the fire.For example, the device can be a charging device for charging accumulators, with which small, mobile objects such as smartphones, laptops and the like can be charged or with which large objects such as electric vehicles can be charged. The object to be charged, which contains a battery (accumulator) which can contain one or more cells, is deposited on the surface of the solidified solid granules. The object is then connected to a charging device of the charging device, so that the battery can be charged with electrical energy.If the breaking out of a fire to the object is now detected with the aid of the detection device, the fire is detected by the control device and an activation signal is then generated, as a result of which the gaseous fluid is blown into the interior of the container and thus into the solid granulate. This creates a fluidized bed into which the ignited object dips. After a certain time has elapsed or by detecting the sufficient sinking into the fluidized bed, the control device now generates the switch-off signal, as a result of which the injection of the gaseous fluid is interrupted and the fluidized bed collapses. The object which has been burned is thus embedded in the solid granules which now solidify.Such a charging device accordingly additionally has a charging device in order to be able to charge the object within the extinguishing device.According to one embodiment, it is provided that the extinguishing agent filling device has an extinguishing agent filling device which is configured to fill an extinguishing agent into the container, wherein the control device is further configured to start filling the extinguishing agent into the container after the switch-off signal for the fluid introduction device has been generated.According to one embodiment, it is provided that the apparatus comprises a cooling device which is configured for cooling the container and / or the solid granules.The invention is explained in more detail by way of example with reference to the appended figures. The following are shown: FIG. 1 is a schematic illustration of the quenching process on a burning object, FIG. 2 shows a schematic illustration of the extinguishing process on an electric car.FIG. 1 shows a schematically greatly simplified illustration of the erasing process by means of the erasing apparatus 10 in the 3 essential method steps a) to c).First, a container 11 with solid granules 12 is provided, the container having an air-permeable bottom 13. As a result, the interior of the container 11 is divided into a working space 14 and a blower space 15. The blower chamber 15 is located below the air-permeable base 13 and is operatively connected to a blower 16, which can blow a gaseous fluid into the blower chamber 15. The solid granules 12 are contained in the working space 14.If, as shown in the first method step a), a gaseous fluid is then blown by the blower 16 into the blower space 15 below the air-permeable base 13, the gaseous fluid is blown by the air-permeable base 13 into the working space 14 of the container 11. This forms a fluidized bed 17 (also referred to as a fluidized bed) which has physical properties of a liquid.The air-permeable base 13 can be, for example, an air-permeable membrane or a perforated plate. The openings should be smaller than the average diameter of the solid particles of the solid granules 12.The blower 16 can be designed in such a way that it draws in the ambient air and introduces it into the blower chamber 15. However, it is also conceivable for special gases, such as CO 2 or an inert gas, to be blown in or pressed in.The combustible object 20 now, as shown in the second method step b), sinks into the formed fluidized bed 17 and in the process sinks down to the air-permeable base 13.After the object 20 has sunk into the container onto the base 13, the blower 16 is switched off, as shown in the third method step c), whereby now no further gas is injected into the blower space 15. The previously formed fluidized bed 17 now collapses and thereby embeds the object 20 into the solidifying solid granules 12.The term "solidifying" solid granules is understood in the sense of the present invention to mean that the solid granules assume the state it had before the fluidized bed was produced. Solidification here means a more solid consistency than the fluidized bed.The control of the blower 16 is effected with the aid of a control device 18 which generates corresponding switch-on and switch-off signals. A sensor 19 can be provided which detects the outbreak of a fire. If the onset of a fire is detected by the sensor 19, a corresponding switch-on signal is generated by the control device 18 and the blower 16 is switched on, whereby the fluidized bed 17 is generated and the object 20 which has been burned dips in. As a result, an ignited object can be automatically extinguished.FIG. 2 shows a case of application for extinguishing and transporting an electric vehicle. The electric vehicle 30 which has been burned is introduced into the generated fluidized bed 17 of the container 11 by means of a crane 31. The electric vehicle 30 then sinks into the container on the ground, wherein the fluidized bed 17 then collapses by switching off the blower and embeds the electric vehicle in the solid granules (method step c)).For support, at least the lower layer in the area of the blower chamber 15 and above the air-permeable base 13 is then flooded with a extinguishing agent 32 in order to thus bring about active cooling. As a result, not only the vehicle 30 is cooled, but also the solid granulate, which has a particularly positive effect on fire fighting of the electric vehicle 30.The solidified solid granules now make transport possible without sloshing charge.List of reference characters10 Apparatus 11 Container 12 Solid granules 13 Air-permeable base 14 Working space 15 Blower space 16 Blower 17 Fluidized bed 18 Control device 19 Sensor 20 Combustible object 30 Electric vehicle 31 Crane 32 Extinguishing agentReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 20 2020 102 574 U1

[0012] DE 10 2016 211 854 B3

[0014]

Claims

Method for extinguishing a fire on an object (20), the method comprising the following steps: - providing a container (11) which contains solid granules (12) of loose solid particles, - generating a fluidized bed (17) within the container (11) filled with the solid granules (12) by introducing a gaseous fluid into the solid granules (12) in such a way that the object (20) which has been burned at least partially sinks into the fluidized bed (17), - wherein the object (20) is introduced into the container (11) before or after the generation of the fluidized bed (17), and - ending the introduction of the gaseous fluid into the container (11) if the object (20) which has been burned has at least partially sunk into the fluidized bed (17), in order to end the production of the fluidized bed (17) and to embed the sunk object (20) at least partially in the solid granulate (12).Method according to claim 1, characterised in that the solid granulate (12) is sand.Method according to claim 1 or 2, characterized in that the gaseous fluid is air or an inert gas or a gaseous fluid which contains at least 50% CO 2, preferably at least 70% CO 2, particularly preferably at least 90% CO 2.Method according to one of the preceding claims, characterized in that, after the production of the fluidized bed (17) has ended, by ending the introduction of the gaseous fluid, a liquid extinguishing agent (32) is introduced into the solid granules (12) embedding the sunk object (20).Method according to one of the preceding claims, characterized in that, at least after the production of the fluidized bed (17) has ended by ending the introduction of the gaseous fluid, the container (11) and / or the solid granules (12) embedding the sunk object (20) are cooled by a coolant and / or a cooling device.Method according to one of the preceding claims, characterized in that the non-burning object (20) is provided on the solid granules (12) in the container (11), wherein a fire on the object (20) is detected by means of a detection device and the generation and termination of the fluidized bed (17) is triggered after the detection of the fire.Method according to one of the preceding claims, characterized in that the object (20) contains a rechargeable battery, in particular a lithium-ion battery.Apparatus (10) for extinguishing a fire on an object (20), comprising - a container (11) which is filled with solid granules (12) of loose solid particles, - a fluid introduction device which is configured for introducing a gaseous fluid into the solid granules (12) for producing a fluidized bed (17) within the container (11) filled with the solid granules (12), and - a control device (18) which is configured to generate a switch-on signal for the fluid introduction device in order to start the production of the fluidized bed (17) when the object (20) which has undergone a fire is or is introduced into the container (11), and to generate a switch-off signal for the fluid introduction device in order to end the production of the fluidized bed (17), if the object (20) which has been burned has at least partially sunk into the fluidized bed (17), in order to embed the object (20) which has been burned at least partially in the solid granulate (12).Device (10) according to claim 8, characterised in that the container (11) has an air-permeable base (13), which is provided at the base of the container (11) and interacts with the fluid introduction device in such a way that the gaseous fluid is introduced through the air-permeable base (13) into the solid granulate (12) for producing the fluidised bed (17).Device (10) according to claim 8 or 9, characterised in that the device (10) has a detection device which is configured to detect a fire on the object (20) located in the container (11), wherein the control device (18) is configured to generate the switch-on signal as a function of the detection of the fire.Apparatus (10) according to claim 10, characterised in that the control device (18) is further configured to interrupt a charging process of the object (20) located in the container (11) as a function of the detection of the fire.Device (10) according to one of Claims 8 to 11, characterized in that the device (10) has an extinguishing agent filling device which is configured to fill an extinguishing agent (32) into the container (11), wherein the control device (18) is furthermore configured to start filling the extinguishing agent (32) into the container (11) after the switch-off signal for the fluid introduction device has been generated.Device (10) according to one of Claims 8 to 12, characterized in that the device (10) comprises a cooling device which is configured to cool the container (11) and / or the solid granules (12).

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