Fire extinguishing method, fire extinguishing system and lithium battery capacity dividing device

Abstract

The present application provides a fire extinguishing method, a fire extinguishing system and a lithium battery capacity component device, which relate to the field of lithium battery production technology. According to the fire extinguishing method provided by the present application, when liquid nitrogen contacts a liquid fire extinguishing agent having a boiling point lower than that of liquid nitrogen, the temperature of the liquid fire extinguishing agent drops sharply to below the freezing point of the liquid fire extinguishing agent. The molecular motion in the liquid fire extinguishing agent slows down and begins to form a solid state, that is, solidification occurs. The liquid fire extinguishing agent forms a solid layer covering the surface of the energy storage structure. This solid layer can not only isolate the energy storage structure from the outside world from heat exchange, but also prevent oxygen from contacting the combustion material in the energy storage structure. By isolating oxygen, the solid layer helps to cut off the conditions for maintaining the fire, thereby achieving the purpose of extinguishing the fire. In addition, the energy storage structure continues to release heat, the solid layer continues to absorb heat, the temperature rises and a phase change occurs. After the fire extinguishing agent stops spraying, the surface temperature of the energy storage structure is still maintained in the low temperature range for a long time.

Description

Technical Field

[0001] The present application relates to the technical field of lithium battery production, and in particular to a fire extinguishing method, a fire extinguishing system and a lithium battery capacity dividing device. Background Art

[0002] As a key link in the production of lithium-ion batteries, fires in the chemical composition workshop have unique characteristics and difficulties. The combustion process of lithium-ion batteries in a highly charged state is complex, and they may skip the self-induction stage and directly enter the thermal runaway stage, reaching an explosion state in a short period of time. In severe cases, a chain reaction may occur in the battery stack. Once a lithium-ion battery catches fire, the fire spreads quickly, the combustion intensity is high, and the temperature is high, making it extremely difficult for personnel to extinguish the fire. Conventional fire extinguishing agents are often difficult to effectively extinguish such fires, especially when the battery is in a highly charged state, the lithium carbide generated at the negative electrode may react with a variety of fire extinguishing agents, resulting in reignition or secondary disasters.

[0003] Existing fire extinguishing methods have obvious shortcomings when facing fires in chemical storage workshops. First, traditional fire extinguishing agents may not be able to effectively extinguish lithium-ion battery fires because the chemical reactions inside the battery may continue after the fire is extinguished, causing re-ignition. Second, the choice of fire extinguishing agents is limited. For example, some dry powder fire extinguishing agents may not provide sufficient cooling effect. In addition, the reaction time of existing fire extinguishing systems may not be sufficient to cope with the rapid development of lithium-ion battery fires. Summary of the invention

[0004] In view of this, the present application provides a fire extinguishing system, the purpose of which is to solve the above technical problems to a certain extent.

[0005] A first aspect of an embodiment of the present application provides a fire extinguishing method, the fire extinguishing method comprising:

[0006] Providing a liquid fire extinguishing agent jet to a surface of the energy storage structure to form a liquid fire extinguishing agent film on the surface of the energy storage structure;

[0007] After the liquid fire extinguishing agent film is formed, stopping providing the liquid fire extinguishing agent jet and providing a liquid nitrogen jet on the surface of the energy storage structure, so that the liquid fire extinguishing agent film solidifies into a solid layer on the surface of the energy storage structure;

[0008] After the liquid fire extinguishing agent film solidifies into the solid layer on the surface of the energy storage structure, continuously providing the liquid fire extinguishing agent jet and the liquid nitrogen jet to the surface of the energy storage structure;

[0009] Wherein, the boiling point of the liquid fire extinguishing agent is higher than the boiling point of the liquid nitrogen.

[0010] On the basis of the above technical solution, optionally, providing a liquid nitrogen jet to the surface of the energy storage structure includes:

[0011] The distance between the starting position of the liquid nitrogen jet and the surface of the energy storage structure is configured to be 10-30 cm, and the liquid nitrogen jet is provided to the surface of the energy storage structure based on the starting position.

[0012] Based on any of the above technical solutions, optionally, providing a liquid fire extinguishing agent jet to the surface of the energy storage structure includes:

[0013] The liquid fire extinguishing agent jet is configured such that the angle between the starting position of the liquid fire extinguishing agent jet and the gravity direction is 0-45 degrees.

[0014] Based on any of the above technical solutions, optionally, providing a liquid nitrogen jet to the surface of the energy storage structure includes:

[0015] The liquid nitrogen jet is configured to have an angle of 0-45 degrees between the starting position of the liquid nitrogen jet and the direction of gravity, and the liquid fire extinguishing agent jet is provided to the surface of the energy storage structure based on the angle between the starting position of the liquid nitrogen jet and the direction of gravity.

[0016] Based on any of the above technical solutions, optionally, the fire extinguishing method further includes:

[0017] The flow ratio of the liquid fire extinguishing agent jet to the liquid nitrogen jet is configured to be 1:3-1:5.

[0018] Based on any of the above technical solutions, optionally, the fire extinguishing method further includes:

[0019] Before providing a liquid fire extinguishing agent jet to the surface of the energy storage structure, the humidity of the environment where the energy storage structure is located is controlled to 20-60% RH.

[0020] A second aspect of the present application provides a fire extinguishing system, the fire extinguishing system is used to perform the fire extinguishing method as described above, the fire extinguishing system comprising:

[0021] A liquid nitrogen spraying mechanism, the liquid nitrogen spraying mechanism comprising a plurality of liquid nitrogen spraying heads for spraying liquid nitrogen;

[0022] A fire extinguishing agent spraying mechanism, the fire extinguishing agent spraying mechanism comprising a plurality of fire extinguishing agent spraying heads for spraying the fire extinguishing agent, the plurality of fire extinguishing agent spraying heads being arranged in one-to-one correspondence with the plurality of liquid nitrogen spraying heads;

[0023] Wherein, the fire extinguishing agent nozzle is arranged above the corresponding liquid nitrogen nozzle, and the fire extinguishing agent nozzle and the corresponding liquid nitrogen nozzle are configured to make the fire extinguishing agent solidify on the surface of the energy storage structure.

[0024] On the basis of the above technical solution, optionally, the liquid nitrogen injection mechanism includes a plurality of liquid nitrogen nozzles arranged in one-to-one correspondence with the plurality of liquid nitrogen nozzles, and the liquid nitrogen nozzles are arranged on the corresponding liquid nitrogen nozzles; the fire extinguishing agent injection mechanism includes a plurality of fire extinguishing agent nozzles arranged in one-to-one correspondence with the plurality of fire extinguishing agent nozzles, and the fire extinguishing agent nozzles are arranged on the corresponding fire extinguishing agent nozzles;

[0025] Wherein, each of the liquid nitrogen nozzles has an adjacent fire extinguishing agent nozzle, and the fire extinguishing system further comprises a heat insulating portion, wherein the heat insulating portion is arranged between each of the liquid nitrogen nozzles and the adjacent fire extinguishing agent nozzle.

[0026] On the basis of any of the above technical solutions, optionally, the liquid nitrogen injection mechanism includes a plurality of first valves corresponding to the plurality of liquid nitrogen nozzles, and each of the liquid nitrogen nozzles is provided with a corresponding first valve; the fire extinguishing agent injection mechanism includes a plurality of second valves corresponding to the plurality of fire extinguishing agent nozzles, and each of the fire extinguishing agent nozzles is provided with a corresponding second valve;

[0027] The first valve is used to control the on-off of the liquid nitrogen nozzle where the first valve is located, and the second valve is used to control the on-off of the fire extinguishing agent nozzle where the second valve is located.

[0028] Based on any of the above technical solutions, optionally, the liquid nitrogen injection mechanism includes a liquid nitrogen main pipe connected to the multiple liquid nitrogen nozzles, wherein the liquid nitrogen injection mechanism includes a third valve, the third valve is arranged at the connection between the liquid nitrogen nozzle and the liquid nitrogen main pipe, and the third valve is used to control the opening and closing of the connection.

[0029] On the basis of any of the above technical solutions, optionally, the liquid nitrogen nozzle and the fire extinguishing agent nozzle are both single-hole direct injection nozzles, or the liquid nitrogen nozzle and the fire extinguishing agent nozzle are both multi-hole direct injection nozzles;

[0030] The liquid nitrogen nozzle and the fire extinguishing agent nozzle are both 10-30 cm away from the energy storage structure;

[0031] The angles between the liquid nitrogen nozzle and the fire extinguishing agent nozzle and the gravity direction are 0-45 degrees.

[0032] A third aspect of the present application provides a lithium battery capacity splitting device, wherein the lithium battery capacity splitting device comprises the fire extinguishing system as described above.

[0033] Based on any of the above technical solutions, optionally, the lithium battery capacity conversion device includes multiple storage locations, the energy storage structure includes lithium batteries, the lithium batteries are arranged in the storage locations, and each of the storage locations is at least corresponding to a group of corresponding liquid nitrogen nozzles and fire extinguishing agent nozzles.

[0034] According to the fire extinguishing method provided in the present application, when liquid nitrogen comes into contact with a liquid fire extinguishing agent having a boiling point lower than that of liquid nitrogen, due to the extremely low temperature of the liquid nitrogen (about -195.8°C), the liquid nitrogen will quickly absorb the heat of the liquid fire extinguishing agent, causing the temperature of the liquid fire extinguishing agent to drop sharply below the freezing point of the liquid fire extinguishing agent. In this case, the molecular motion in the liquid fire extinguishing agent slows down and begins to form a solid state, that is, solidification occurs. In this way, the liquid fire extinguishing agent forms a solid layer covering the surface of the energy storage structure. This solid layer can not only isolate the energy storage structure from the outside world, but also prevent oxygen from contacting the combustion material in the energy storage structure. By isolating oxygen, the solid layer helps to cut off the conditions for maintaining the fire, thereby achieving the purpose of extinguishing the fire. In addition, the energy storage structure continues to release heat, the solid layer continues to absorb heat, the temperature rises and a phase change occurs. After the fire extinguishing agent stops spraying, the surface temperature of the energy storage structure is still maintained in the low temperature range for a long time.

[0035] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A comparison chart of the low temperature maintenance time of the fire extinguishing method provided in an embodiment of the present application and other fire extinguishing methods is shown.

[0038] Figure 2 A comparison chart of the temperature recovery peak value and the average cooling rate of the fire extinguishing method provided according to an embodiment of the present application and other fire extinguishing methods is shown.

[0039] Figure 3 A schematic diagram showing a flow chart of a fire extinguishing method provided according to an embodiment of the present application.

[0040] Figure 4 A schematic diagram of a three-dimensional diagram of a lithium battery capacity conversion device provided according to an embodiment of the present application is shown.

[0041] Figure 5 A schematic diagram showing a plan view of a lithium battery capacity conversion device provided according to an embodiment of the present application is shown.

[0042] Figure 6 A schematic diagram showing another plan view of a lithium battery capacity conversion device provided according to an embodiment of the present application is shown.

[0043] Figure 7 A schematic diagram showing a cross-sectional view of a storage location of a lithium battery capacity conversion device provided in an embodiment of the present application is shown.

[0044] Figure 8 A schematic diagram of the internal structure of a liquid nitrogen storage room of a lithium battery fractionation device provided in accordance with an embodiment of the present application is shown.

[0045] Fig. 9 A schematic diagram of a liquid nitrogen injection pipeline network of a hidden portion of a storage structure of a lithium battery capacity conversion device provided in an embodiment of the present application is shown.

[0046] Fig.10 for Fig. 9 Schematic diagram of an enlarged view of the middle part of the structure.

[0047] Fig.11 A schematic diagram of a water jetting pipe network for hiding a partial storage structure of a lithium battery capacity conversion device provided in an embodiment of the present application is shown.

[0048] Fig.12 for Fig.11 Schematic diagram of an enlarged view of the middle part of the structure.

[0049] Fig.13 This is a linkage logic diagram taking a row of storage locations of a lithium battery capacity conversion device provided in an embodiment of the present application as an example.

[0050] Reference numerals:

[0051] 1-storage location; 2-external observation window; 3-heat dissipation port; 4-needle bed; 5-temperature probe; 6-lithium-ion battery; 7-CO detector; 8-smoke detector; 9-fire host; 10-solenoid valve; 11-water injection network; 111-water main pipeline; 112-water injection pipeline; 113-water nozzle; 12-liquid nitrogen injection network; 121-liquid nitrogen main pipeline; 122-liquid nitrogen injection pipeline; 123-liquid nitrogen nozzle; 13-liquid nitrogen storage room; 131-Dewar flask; 132-pressure gauge; 133-liquid level gauge; 134-inlet and outlet valves; 135-boosting valve; 136-safety valve; 137-low-temperature solenoid valve. DETAILED DESCRIPTION

[0052] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0053] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0054] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0056] According to a first aspect of an embodiment of the present application, a fire extinguishing method is provided. Figures 1 to 3 Describe in detail the steps of the fire extinguishing method.

[0057] According to the fire extinguishing method provided in the embodiment of the present application, the fire extinguishing method includes: providing a liquid fire extinguishing agent jet to the surface of the energy storage structure to form a liquid fire extinguishing agent film on the surface of the energy storage structure. After the liquid fire extinguishing agent film is formed, stop providing the liquid fire extinguishing agent jet and provide a liquid nitrogen jet to the surface of the energy storage structure, so that the liquid fire extinguishing agent film solidifies into a solid layer on the surface of the energy storage structure. After the liquid fire extinguishing agent film solidifies into a solid layer on the surface of the energy storage structure, continue to provide a liquid fire extinguishing agent jet and a liquid nitrogen jet to the surface of the energy storage structure. In an embodiment, the boiling point of the liquid fire extinguishing agent is higher than the boiling point of liquid nitrogen.

[0058] Thus, according to the fire extinguishing method provided in the embodiment of the present application, when liquid nitrogen contacts a liquid fire extinguishing agent having a boiling point lower than that of liquid nitrogen, due to the extremely low temperature of the liquid nitrogen (about -195.8°C), the liquid nitrogen will quickly absorb the heat of the liquid fire extinguishing agent, causing the temperature of the liquid fire extinguishing agent to drop sharply below the freezing point of the liquid fire extinguishing agent. In this case, the molecular motion in the liquid fire extinguishing agent slows down and begins to form a solid state, that is, solidification occurs. In this way, the liquid fire extinguishing agent forms a solid layer covering the surface of the energy storage structure. This solid layer can not only isolate the energy storage structure from the outside world, but also prevent oxygen from contacting the combustion material in the energy storage structure. By isolating oxygen, the solid layer helps to cut off the conditions for maintaining the fire, thereby achieving the purpose of extinguishing the fire. In addition, the energy storage structure continues to release heat, the solid layer continues to absorb heat, the temperature rises and a phase change occurs. After the fire extinguishing agent stops spraying, the surface temperature of the energy storage structure is still maintained in the low temperature range for a long time.

[0059] Next, according to the fire extinguishing method provided in the embodiment of the present application, after the liquid fire extinguishing agent crystal layer is formed, the internal reaction (such as internal chain reaction) of the energy storage structure continues to release heat, and the temperature of the solid layer covering the surface of the energy storage structure rises and undergoes a phase change, and the whole process continues to absorb heat. After the fire extinguishing agent stops spraying, the surface temperature of the energy storage structure is maintained in the low temperature range for a long time, significantly reducing the peak value of the surface temperature rise of the energy storage structure to prevent re-ignition.

[0060] In addition, liquid nitrogen will also gasify when cooling liquid fire extinguishing agents. After liquid nitrogen gasifies into nitrogen, a nitrogen-rich environment will be formed in the local space. As an inert gas, nitrogen will not support combustion. When the proportion of nitrogen in the air increases, it will dilute the oxygen concentration in the air, reduce the intensity of the combustion reaction, and further inhibit the spread of the fire. At the same time, nitrogen can also displace combustible gases and reduce the risk of explosion.

[0061] Based on the above advantages of the fire extinguishing method provided according to the embodiment of the present application, the steps of the above fire extinguishing method will be described in detail below.

[0062] In the embodiment, the "energy storage structure" mentioned in the above description should be understood as a structure that can store and provide energy to the outside. Here, the stored energy can be, for example, chemical energy, and the energy provided to the outside can be, for example, electrical energy. Therefore, as an example, the energy storage structure can be, for example, a battery structure. Here, the battery structure includes but is not limited to a single cell and a battery pack. In addition, the battery structure can also include a pole group structure formed by winding or stacking a positive electrode sheet, a negative electrode sheet, and a separator.

[0063] In the embodiment, the surface of the energy storage structure should be understood to include the outer surface of the energy storage structure, and the surface of the energy storage structure can contact the liquid fire extinguishing agent provided by the liquid fire extinguishing agent jet, thereby exchanging heat with the liquid fire extinguishing agent. As an example, taking the energy storage structure as a single battery as an example, the surface of the energy storage structure can be, for example, the outer surface of the shell of the single battery.

[0064] In the embodiment, according to the fire extinguishing method provided in the embodiment of the present application, the provided liquid fire extinguishing agent and liquid nitrogen are both jets, and the jet here should be understood to include the following meanings: spraying a fluid in a beam. In other words, according to the fire extinguishing method provided in the embodiment of the present application, what is sprayed onto the surface of the energy storage structure is a beam of fluid, not an atomized fluid.

[0065] The atomization fire extinguishing strategy commonly used in related technologies is to spray the fire extinguishing material into the space where the burning object is located in the form of an atomizing nozzle, such as the fire extinguishing strategy of using a smoke alarm and a water mist nozzle commonly used in the field of building fire protection. This fire extinguishing strategy aims to break up the fluid in the pipeline into fine water droplets through atomization. When these fine water droplets are sprayed from the nozzle, they often have a high acceleration component in the horizontal direction (expecting to expand the lateral diffusion of the water mist), while the acceleration component in the gravity direction is small. Most of the fine water droplets are close to a natural falling state. Therefore, using this nozzle structure, a large-scale columnar water mist from top to bottom in the space can be obtained.

[0066] Therefore, in the relevant technology, the key idea of ​​the atomization fire extinguishing strategy is to expand the surface area of ​​the fire extinguishing material to achieve sufficient heat exchange with the burning material.

[0067] Based on this atomization fire extinguishing strategy, another type of atomization fire extinguishing strategy has been derived in related technologies. It is also based on the formation of water mist and the addition of liquid nitrogen atomization spray, that is, forming liquid nitrogen mist superimposed on water mist (due to this atomization effect, liquid nitrogen droplets will actually vaporize quickly), increasing the cooling capacity of the water mist, and the tiny water droplets in the water mist will even form many tiny ice crystals in the superposition with the liquid nitrogen mist. These ice crystals will eventually re-liquefy and vaporize in the process of falling toward the burning object or after falling on the burning object, thereby playing a role in extinguishing the fire.

[0068] However, the fire extinguishing method provided according to the embodiment of the present application does not utilize the characteristics of the liquid fire extinguishing agent's form change in the air (that is, the fire extinguishing method provided according to the embodiment of the present application does not utilize the atomized liquid fire extinguishing agent to provide a high heat exchange area), but utilizes the solidified solid layer formed by the liquid fire extinguishing agent after contacting the surface of the energy storage structure to isolate the energy storage structure from the heat exchange with the outside world and to isolate the surface of the energy storage structure from oxygen.

[0069] The fire extinguishing method provided in the embodiment of the present application provides liquid fire extinguishing agent and liquid nitrogen by jet, which is also intended to ensure that the liquid fire extinguishing agent and liquid nitrogen reach the surface of the energy storage structure in the fastest way. The jets of the liquid fire extinguishing agent and liquid nitrogen are concentrated toward the surface of the energy storage structure.

[0070] Therefore, according to the fire extinguishing method provided in the embodiment of the present application, a jet method different from atomization is adopted to provide liquid fire extinguishing agent and liquid nitrogen, so as to avoid the liquid fire extinguishing agent from solidifying before reaching the energy storage structure as much as possible (when water is used as the liquid fire extinguishing agent, ice crystals are formed). At the same time, it can also avoid the rapid vaporization of liquid nitrogen due to the increase in heat exchange area with air as much as possible, that is, the loss of cooling capacity of liquid nitrogen can be minimized as much as possible.

[0071] As an example, for liquid fire extinguishing agent and liquid nitrogen, the jet can be a single stream, which can be achieved by a single-hole direct-injection nozzle. In other examples, the jet can also be multiple streams, which can be achieved by a multi-hole direct-injection nozzle.

[0072] According to the fire extinguishing method provided in the embodiment of the present application, the liquid fire extinguishing agent can be, for example, water. Therefore, in the above example, the solid layer of the liquid fire extinguishing agent can actually be an ice layer. In other words, the water as a liquid fire extinguishing agent freezes on the surface of the energy storage structure to form an ice layer to isolate the heat exchange between the surface of the energy storage structure and the external environment, and to isolate the surface of the energy storage structure from oxygen.

[0073] In an embodiment, according to the fire extinguishing method provided in an embodiment of the present application, a liquid fire extinguishing agent jet is first provided to the surface of the energy storage structure to form a liquid fire extinguishing agent film on the surface of the energy storage structure, and then a liquid nitrogen jet is provided to the surface of the energy storage structure to cool the liquid fire extinguishing agent film into a solid layer.

[0074] That is to say, in the embodiment, before continuously providing the liquid fire extinguishing agent jet and the liquid nitrogen jet to the surface of the energy storage structure, a small amount of liquid fire extinguishing agent is first provided to the surface of the energy storage structure by using the liquid fire extinguishing agent jet to form a liquid fire extinguishing agent film, and the liquid fire extinguishing agent film is used to form the initial solid layer. This initial solid layer can effectively ensure that the liquid fire extinguishing agent continues to solidify on the surface of the energy storage structure during the subsequent continuous provision, because, due to the existence of the initial solid layer, the liquid fire extinguishing agent film attached to the outside of the initial solid layer is more likely to condense based on the initial solid layer, thereby forming a new solid layer, and the outside of the new solid layer will be covered with a new liquid fire extinguishing agent film to cycle this process.

[0075] For the energy storage structure covered by the solid layer, taking a single cell as an example, if the single cell thermal runaway catches fire, the formation of the solid layer isolates the single cell from the external environment, and exchanges heat with the single cell with a higher temperature, and melts into liquid in the continuous heat exchange process. Thus, a cycle of "internal solid layer melts and absorbs heat, and the external solid layer continues to form" is formed. While exchanging heat with the energy storage structure, the energy storage structure is always or almost always isolated from the external environment.

[0076] According to the fire extinguishing method provided in an embodiment of the present application, providing a liquid nitrogen jet to the surface of the energy storage structure includes: configuring the distance between the starting position of the liquid nitrogen jet and the surface of the energy storage structure to be 10-30 cm, and providing the liquid nitrogen jet to the surface of the energy storage structure based on the starting position.

[0077] In an embodiment, the starting position of the liquid nitrogen jet can be, for example, the outlet position of the nozzle for forming the liquid nitrogen jet from a structural point of view. Since the jet is used to provide liquid nitrogen, the above distance can be understood as the injection distance of the liquid nitrogen jet. In this injection distance, if the distance is too far, for example, greater than 30 cm, since the boiling point of liquid nitrogen at normal pressure is -196°C, the liquid nitrogen will be vaporized in large quantities before reaching the surface of the energy storage structure, and a large amount of cold will be lost, reducing the refrigeration effect. In the injection distance, the distance cannot be too close, for example, less than 10 cm. A distance that is too close will cause the liquid nitrogen to rebound and sputter on the surface of the energy storage structure, causing the loss of liquid nitrogen. A distance that is too close may also cause low-temperature damage to the nozzle.

[0078] In an embodiment, the spray distance of the liquid fire extinguishing agent jet may also adopt the above distance range. Similar to liquid nitrogen, the liquid fire extinguishing agent may still be partially lost or atomized in the air at a spray distance greater than 30 cm, and cannot effectively gather and freeze on the surface of the energy storage structure. When the spray distance is less than 10 cm, the splash of the liquid fire extinguishing agent causes the amount of liquid fire extinguishing agent effectively attached to the surface of the energy storage structure to decrease, and the close-range impact of the liquid fire extinguishing agent will also hinder the formation of a solid layer.

[0079] As an example, in an embodiment, the spray distance may be, for example, 10 cm, 11 cm, 12 cm, 13 cm, 14 cm, 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm or 30 cm.

[0080] According to the fire extinguishing method provided in an embodiment of the present application, providing a jet of liquid fire extinguishing agent to the surface of the energy storage structure includes: configuring the liquid fire extinguishing agent jet to have an angle of 0-45 degrees between the starting position of the liquid fire extinguishing agent jet and the direction of gravity, and providing the liquid fire extinguishing agent jet to the surface of the energy storage structure based on the angle between the starting position of the liquid fire extinguishing agent jet and the direction of gravity.

[0081] In the embodiment, when the starting position, that is, the angle between the nozzle outlet and the gravity direction is 0 degrees, the angle of the liquid fire extinguishing agent jet is the gravity direction. In this case, the surface of the energy storage structure, such as the upper surface, can be arranged to be perpendicular to the liquid fire extinguishing agent jet, so that the liquid fire extinguishing agent jet can be evenly distributed on the surface of the energy storage structure. For example, when icing a flat object such as a metal plate, vertical spraying can make the liquid adhere to the surface better, avoiding the liquid flowing due to tilted spraying, which affects the icing effect.

[0082] However, for energy storage structures, especially battery structures, such as single cells, due to thermal runaway, internal gas production breaks through the valve, and the early ejection of combustible mixed gas and positive electrode material particles with a relatively high pressure (≥1.5MPa) can easily clog the nozzle of the liquid fire extinguishing agent. Therefore, the nozzle can be tilted relative to the direction of gravity (the maximum tilt angle is 45 degrees, and a larger tilt angle will cause the liquid fire extinguishing agent to flow quickly from the surface of the energy storage structure), which can ensure that the liquid fire extinguishing agent is evenly distributed on the surface of the energy storage structure and reduce the risk of nozzle clogging.

[0083] In an embodiment, the above angles are substantial spray angles of the liquid fire extinguishing agent, which may specifically be 0 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees or 45 degrees.

[0084] According to the fire extinguishing method provided in the embodiment of the present application, the liquid nitrogen jet can also be configured to have an angle of 0-45 degrees between the starting position of the liquid nitrogen jet and the gravity direction, and the liquid fire extinguishing agent jet is provided to the surface of the energy storage structure based on the angle between the starting position of the liquid nitrogen jet and the gravity direction. The angle range here is the actual liquid nitrogen injection angle, and its beneficial effects are the same as above, which will not be repeated here.

[0085] The fire extinguishing method provided according to the embodiment of the present application also includes: configuring the flow rate ratio of the liquid fire extinguishing agent jet to the liquid nitrogen jet to be 1:3-1:5. That is to say, in terms of the injection flow rate, the flow rate of liquid nitrogen is relatively larger than that of liquid fire extinguishing agent to ensure that there is enough cold to quickly freeze the liquid fire extinguishing agent, especially water as a liquid fire extinguishing agent, and to reduce the ambient temperature. In addition, appropriately increasing the injection speed and pressure helps the rapid distribution and cooling of the liquid on the surface of the energy storage structure.

[0086] In an embodiment, as an example, the flow ratio of the liquid fire extinguishing agent to the liquid nitrogen may be, for example, 1:3, 1:3.1, 1:3.3, 1:3.7, 1:4, 1:4.5 or 1:5.

[0087] According to the fire extinguishing method provided in the embodiment of the present application, the fire extinguishing method further includes: before providing the liquid fire extinguishing agent jet to the surface of the energy storage structure, controlling the humidity of the environment where the energy storage structure is located to 20-60%RH. In the embodiment, the humidity of the environment where the energy storage structure is located at 20-60%RH is conducive to promoting the subsequent liquid fire extinguishing agent film to solidify into a solid layer. In the embodiment, especially when the ambient humidity exceeds the upper limit of the range, excessive air humidity may cause a portion of the liquid fire extinguishing agent dispersed in the air by the liquid fire extinguishing agent jet to directly condense into solid particles, thereby causing the loss of the liquid fire extinguishing agent.

[0088] In order to further verify the technical effect of this technical solution, experiments were conducted on liquid nitrogen and liquid fire extinguishing agent (taking water as an example). The experiment used a 106Ah ternary lithium battery with a SOC of 100%, and conducted the following four working conditions, each of which was repeated twice.

[0089] Table 1 Experimental conditions

[0090]

[0091] The experimental results are shown in the attached figure. The ice layer formed by the simultaneous injection of liquid nitrogen and water is taken as the time of injection of the fire extinguishing agent as 0 point. Figure 1 It shows that the fire extinguishing method of the embodiment of the present application, after the liquid nitrogen and water are sprayed simultaneously for 20s, has a stronger low-temperature maintenance ability (the time the battery cell surface is below 150°C is extended by 4-5 times) compared with the single spray of water or liquid nitrogen. In addition, the fire extinguishing method of the embodiment of the present application, the peak value of the battery cell surface temperature recovery is significantly reduced to only 181°C, indicating that the thermal runaway of the battery is effectively controlled. It can be seen that the fire extinguishing method of the embodiment of the present application, in which the combined action of liquid nitrogen and water can have a good inhibitory effect on the re-ignition of lithium batteries.

[0092] According to the second aspect of the embodiment of the present application, a fire extinguishing system is provided, and the fire extinguishing system is used to perform the above fire extinguishing method, and the fire extinguishing system includes a liquid nitrogen injection mechanism and a fire extinguishing agent injection mechanism. In the embodiment, the liquid nitrogen injection mechanism includes a plurality of liquid nitrogen nozzles for spraying liquid nitrogen, and the fire extinguishing agent injection mechanism includes a plurality of fire extinguishing agent nozzles for spraying fire extinguishing agent, and the aforementioned plurality of fire extinguishing agent nozzles are arranged one-to-one with the aforementioned plurality of liquid nitrogen nozzles. Among them, the fire extinguishing agent nozzle is arranged above the corresponding liquid nitrogen nozzle to avoid the liquid nitrogen nozzle from intersecting with the jet of liquid fire extinguishing agent and gasifying when spraying liquid nitrogen. The fire extinguishing agent nozzle and the corresponding liquid nitrogen nozzle are configured to make the fire extinguishing agent solidify on the surface of the energy storage structure, and the solidification method here is the process mentioned in the above fire extinguishing method, and its beneficial effects are also the same as above, which will not be repeated here.

[0093] According to the fire extinguishing system provided in the embodiment of the present application, the liquid nitrogen injection mechanism may include a plurality of liquid nitrogen nozzles arranged in one-to-one correspondence with the aforementioned plurality of liquid nitrogen nozzles, and the liquid nitrogen nozzles are arranged on the corresponding liquid nitrogen nozzles, and the fire extinguishing agent injection mechanism includes a plurality of fire extinguishing agent nozzles arranged in one-to-one correspondence with the aforementioned plurality of fire extinguishing agent nozzles, and the fire extinguishing agent nozzles are arranged on the corresponding fire extinguishing agent nozzles. In the embodiment, each liquid nitrogen nozzle has an adjacently arranged fire extinguishing agent nozzle, and the fire extinguishing system further includes an insulation portion, and an insulation portion is arranged between each liquid nitrogen nozzle and the adjacently arranged fire extinguishing agent nozzle, such as an insulation layer formed by an insulation material, and the insulation layer may also be further coated on the outside of the liquid nitrogen nozzle. In addition, in the embodiment, the liquid nitrogen nozzle is a low-temperature nozzle.

[0094] According to the fire extinguishing system provided in the embodiment of the present application, the liquid nitrogen injection mechanism may include a plurality of first valves corresponding one-to-one to the plurality of liquid nitrogen nozzles, and each liquid nitrogen nozzle may be provided with a corresponding first valve (the first valve here, the subsequent second valve and the third valve are all solenoid valves, which will be mentioned in the subsequent specific description), and the fire extinguishing agent injection mechanism may include a plurality of second valves corresponding one-to-one to the plurality of fire extinguishing agent nozzles, and each fire extinguishing agent nozzle may be provided with a corresponding second valve, the first valve is used to control the on-off of the liquid nitrogen nozzle where the first valve is located, and the second valve can be used to control the on-off of the fire extinguishing agent nozzle where the second valve is located.

[0095] According to the fire extinguishing system provided in the embodiment of the present application, the liquid nitrogen injection mechanism includes a liquid nitrogen main pipe connected to the aforementioned multiple liquid nitrogen nozzles, wherein the liquid nitrogen injection mechanism may include a third valve, the third valve may be arranged at the connection point between the liquid nitrogen nozzle and the liquid nitrogen main pipe, and the third valve may be used to control the on-off of the connection point.

[0096] In addition, according to the fire extinguishing system provided in the embodiment of the present application, as mentioned in the above description, the liquid nitrogen nozzle and the fire extinguishing agent nozzle can both be single-hole direct spray nozzles, or the liquid nitrogen nozzle and the fire extinguishing agent nozzle can both be multi-hole direct spray nozzles. The liquid nitrogen nozzle and the fire extinguishing agent nozzle can be 10-30cm away from the energy storage structure, that is, the injection distance as above. The angle between the liquid nitrogen nozzle and the fire extinguishing agent nozzle and the gravity direction is 0-45 degrees, that is, the injection angle as above.

[0097] According to a third aspect of an embodiment of the present application, a lithium battery capacity splitting device is provided. The lithium battery capacity splitting device includes the above fire extinguishing system and the above beneficial effects, which will not be repeated here.

[0098] According to the lithium battery capacity conversion device provided in the embodiment of the present application, see Figures 4 to 13 The lithium battery componentization device includes multiple storage locations, the energy storage structure includes lithium batteries, and the lithium batteries are arranged in the storage locations. Each storage location is at least corresponding to a group of liquid nitrogen nozzles and fire extinguishing agent nozzles.

[0099] The lithium battery componentization device will be further described below, wherein a description of the specific structure of the fire extinguishing system will be further interspersed.

[0100] A lithium battery chemical separation device, for example, a chemical separation workshop, wherein the main body of the chemical separation workshop includes a chemical separation cabinet and a stack of lithium-ion batteries 6 distributed in a storage location 1 of the separation cabinet; the chemical separation cabinet includes a cabinet door, an external observation window 2, a heat dissipation port 3 and a needle bed 4. In an embodiment, the cabinet door is used to open the storage location. The external observation window 2 is used to observe the internal situation of the storage location, check the battery status, etc. The heat dissipation port 3 is used to dissipate the heat generated by the battery during the charging and discharging process to maintain a stable temperature in the storage location. The needle bed 4 is an electrical connection device used for battery testing and charging and discharging, and has a built-in temperature probe 5.

[0101] The fire extinguishing system may also include a fire host 9, a fire sensing module and a fire extinguishing system. The fire host is equipped with a control system to receive and process signals from fire detectors and to work in conjunction with liquid nitrogen, liquid fire extinguishing agent injection pipe networks, fire doors, smoke exhaust systems, etc. When signs of fire are detected, the storage location process is immediately suspended, the fire protection system of the corresponding storage location is activated, and an alarm is issued to notify relevant personnel.

[0102] The fire sensing module may include temperature sensors, smoke sensors and CO (carbon monoxide) detectors 7, which are installed at each storage location of the chemical storage cabinet. The temperature sensor is a temperature probe on a needle bed, the CO detector is placed at the upper left of the storage location, and two smoke detectors 8 are arranged at the left front and right rear of the storage location. Each group of detection modules is connected to the fire host signal. When the detection module at any battery stack reaches the fire threshold, it sends a signal to the fire host and opens the valve according to the linkage logic to start the fire extinguishing system.

[0103] As mentioned in the above description, the fire extinguishing system adopts a liquid nitrogen-based multiphase fire extinguishing agent combined injection method, specifically including the above-mentioned liquid fire extinguishing agent injection mechanism and liquid nitrogen injection mechanism. Each system extends into each storage location of the chemical component storage cabinet through pipes and valves, toward its corresponding battery stack.

[0104] For the liquid fire extinguishing agent injection mechanism, taking water spray as an example, it is composed of a water injection pipeline in the storage location, a water injection pipeline network 11 and a solenoid valve 10. Water injection pipelines are provided on both sides of the storage location, and the water injection pipelines are parallel to the liquid nitrogen injection pipelines and are placed above the liquid nitrogen injection pipelines. A water nozzle 113 is provided on the water injection pipeline for spraying water. The water injection pipeline network 11 is composed of a water main pipeline 111 and a water injection pipeline 112. The water main pipeline is connected to the building fire sprinkler main pipeline, and is connected to the water injection pipeline in the component compartment to transport water from the building fire sprinkler system to the water injection pipelines corresponding to each storage location. The solenoid valve is arranged on the water main pipeline and the water injection pipeline, and the opening and closing of the valve can be remotely controlled by the fire host through electromagnetic signals, so that water can be quickly sprayed when a fire occurs.

[0105] As for the liquid nitrogen injection mechanism, the liquid nitrogen injection mechanism is composed of a liquid nitrogen storage room 13, a liquid nitrogen injection pipeline in the storage position 1, a liquid nitrogen injection pipe network 12 and a solenoid valve 10. The liquid nitrogen storage room 13 is composed of a Dewar flask 131, a pressure gauge 132, a liquid level gauge 133, a low-temperature solenoid valve 137, an inlet and outlet liquid valve 134, a booster valve 135 and a safety valve 136, and liquid nitrogen is transported to each storage position through a pipe network.

[0106] In the embodiment, the Dewar flask stores cryogenic liquid nitrogen, the pressure gauge indicates the pressure of the inner cylinder of the flask, the liquid level gauge indicates the height of the liquid level in the container more intuitively, the installation position should be convenient for the operator to observe and repair, and the cryogenic solenoid valve responds quickly to release liquid nitrogen in time for fire extinguishing. When the Dewar flask is filled with liquid, the inlet and outlet valve uses this valve to discharge the gas in the gas phase space in the flask to reduce the pressure in the flask so that the liquid can be filled quickly and smoothly. Another function is that when the pressure in the Dewar flask exceeds the maximum working pressure during storage or other situations, this valve can be used to manually discharge the gas in the flask to reduce the pressure in the flask. Booster valve, after this valve is opened, the gas in the nitrogen bottle will enter the Dewar flask, so that the gas bottle will establish a certain driving pressure (internal pressure) to drive the cryogenic liquid in the bottle to make it flow. Safety valve: when the pressure of the container is greater than the maximum working pressure, it automatically releases the pressure, and its starting pressure is slightly greater than the maximum working pressure.

[0107] In the embodiment, liquid nitrogen injection pipelines are provided on both sides of the storage location, and the liquid nitrogen injection pipelines are parallel to the water injection pipelines and are placed below the water injection pipelines. A liquid nitrogen nozzle 123 is provided on the liquid nitrogen injection pipeline for spraying liquid nitrogen. The liquid nitrogen injection pipeline network 12 is composed of a liquid nitrogen main pipeline 121 and a liquid nitrogen injection pipeline 122. The liquid nitrogen main pipeline connects the liquid nitrogen storage room and the liquid nitrogen injection pipeline, and transports liquid nitrogen from the liquid nitrogen storage room to the liquid nitrogen injection pipelines corresponding to each storage location. The solenoid valve is arranged on the liquid nitrogen main pipeline and the liquid nitrogen injection pipeline, and the opening and closing of the valve can be remotely controlled on the fire host through electromagnetic signals, so that liquid nitrogen can be quickly sprayed when a fire occurs.

[0108] When any of the carbon monoxide concentration, smoke conditions and temperature conditions detected at any storage location reaches the fire threshold, a signal is sent to the fire host, which notifies the monitoring personnel to check whether a fire has occurred. If a fire is confirmed, the fire extinguishing system is manually activated to accurately locate the fire point and spray fire extinguishing agent to extinguish the fire.

[0109] When any storage location detects that two or more dangerous indicators such as carbon monoxide concentration, smoke conditions, and temperature conditions reach the fire threshold, it sends a signal to the fire host and opens the corresponding valve. The fire host notifies the monitoring personnel that a fire has occurred. At the same time, the fire host starts the fire extinguishing system and accurately sprays the corresponding fire extinguishing medium through the valve to the battery storage location corresponding to the fire, accurately locating the fire point and spraying the fire extinguishing agent to extinguish the fire.

[0110] The above are only preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. All equivalent structural changes made by using the contents of the present application specification and drawings under the innovative concept of the present application, or directly / indirectly applied in other related technical fields are included in the protection scope of the present application.

Claims

1. A fire extinguishing method, characterized in that: The fire extinguishing method comprises: Providing a liquid fire extinguishing agent jet to a surface of the energy storage structure to form a liquid fire extinguishing agent film on the surface of the energy storage structure; After the liquid fire extinguishing agent film is formed, stopping providing the liquid fire extinguishing agent jet and providing a liquid nitrogen jet on the surface of the energy storage structure, so that the liquid fire extinguishing agent film solidifies into a solid layer on the surface of the energy storage structure; After the liquid fire extinguishing agent film solidifies into the solid layer on the surface of the energy storage structure, continuously providing the liquid fire extinguishing agent jet and the liquid nitrogen jet to the surface of the energy storage structure; Wherein, the boiling point of the liquid fire extinguishing agent is higher than the boiling point of the liquid nitrogen.

2. The fire extinguishing method according to claim 1, characterized in that: Providing a liquid nitrogen jet to the surface of the energy storage structure comprises: The distance between the starting position of the liquid nitrogen jet and the surface of the energy storage structure is configured to be 10-30 cm, and the liquid nitrogen jet is provided to the surface of the energy storage structure based on the starting position.

3. The fire extinguishing method according to claim 1, characterized in that: Providing a liquid fire extinguishing agent jet to the surface of the energy storage structure comprises: The liquid fire extinguishing agent jet is configured to have an angle of 0-45 degrees between the starting position of the liquid fire extinguishing agent jet and the direction of gravity, and the liquid fire extinguishing agent jet is provided to the surface of the energy storage structure based on the angle between the starting position of the liquid fire extinguishing agent jet and the direction of gravity.

4. The fire extinguishing method according to claim 1, characterized in that: Providing a liquid nitrogen jet to the surface of the energy storage structure comprises: The liquid nitrogen jet is configured to have an angle of 0-45 degrees between the starting position of the liquid nitrogen jet and the direction of gravity, and the liquid fire extinguishing agent jet is provided to the surface of the energy storage structure based on the angle between the starting position of the liquid nitrogen jet and the direction of gravity.

5. The fire extinguishing method according to claim 1, characterized in that: The fire extinguishing method further comprises: The flow ratio of the liquid fire extinguishing agent jet to the liquid nitrogen jet is configured to be 1:3-1:

5.

6. The fire extinguishing method according to claim 1, characterized in that: The fire extinguishing method further comprises: Before providing a liquid fire extinguishing agent jet to the surface of the energy storage structure, the humidity of the environment where the energy storage structure is located is controlled to 20-60% RH.

7. A fire extinguishing system, characterized in that: The fire extinguishing system is used to perform the fire extinguishing method according to any one of claims 1 to 6, and the fire extinguishing system comprises: A liquid nitrogen spraying mechanism, the liquid nitrogen spraying mechanism comprising a plurality of liquid nitrogen spraying heads for spraying liquid nitrogen; A fire extinguishing agent spraying mechanism, the fire extinguishing agent spraying mechanism comprising a plurality of fire extinguishing agent spraying heads for spraying the fire extinguishing agent, the plurality of fire extinguishing agent spraying heads being arranged in one-to-one correspondence with the plurality of liquid nitrogen spraying heads; Wherein, the fire extinguishing agent nozzle is arranged above the corresponding liquid nitrogen nozzle, and the fire extinguishing agent nozzle and the corresponding liquid nitrogen nozzle are configured to make the fire extinguishing agent solidify on the surface of the energy storage structure.

8. The fire extinguishing system according to claim 7, characterized in that: The liquid nitrogen spray mechanism includes a plurality of liquid nitrogen spray pipes arranged in one-to-one correspondence with the plurality of liquid nitrogen spray heads, and the liquid nitrogen spray heads are arranged on the corresponding liquid nitrogen spray pipes; the fire extinguishing agent spray mechanism includes a plurality of fire extinguishing agent spray pipes arranged in one-to-one correspondence with the plurality of fire extinguishing agent spray heads, and the fire extinguishing agent spray heads are arranged on the corresponding fire extinguishing agent spray pipes, Wherein, each of the liquid nitrogen nozzles has an adjacent fire extinguishing agent nozzle, and the fire extinguishing system further comprises a heat insulating portion, wherein the heat insulating portion is arranged between each of the liquid nitrogen nozzles and the adjacent fire extinguishing agent nozzle.

9. The fire extinguishing system according to claim 8, characterized in that: The liquid nitrogen injection mechanism includes a plurality of first valves corresponding to the plurality of liquid nitrogen nozzles one by one, and each of the liquid nitrogen nozzles is provided with a corresponding first valve; the fire extinguishing agent injection mechanism includes a plurality of second valves corresponding to the plurality of fire extinguishing agent nozzles one by one, and each of the fire extinguishing agent nozzles is provided with a corresponding second valve, The first valve is used to control the on-off of the liquid nitrogen nozzle where the first valve is located, and the second valve is used to control the on-off of the fire extinguishing agent nozzle where the second valve is located.

10. The fire extinguishing system according to claim 8, characterized in that: The liquid nitrogen injection mechanism includes a liquid nitrogen main pipe connected to the multiple liquid nitrogen nozzles, wherein the liquid nitrogen injection mechanism includes a third valve, which is arranged at the connection between the liquid nitrogen nozzle and the liquid nitrogen main pipe, and the third valve is used to control the opening and closing of the connection.

11. The fire extinguishing system according to any one of claims 7 to 10, characterized in that: The liquid nitrogen nozzle and the fire extinguishing agent nozzle are both single-hole direct injection nozzles, or the liquid nitrogen nozzle and the fire extinguishing agent nozzle are both multi-hole direct injection nozzles; The liquid nitrogen nozzle and the fire extinguishing agent nozzle are both 10-30 cm away from the energy storage structure; The angles between the liquid nitrogen nozzle and the fire extinguishing agent nozzle and the gravity direction are 0-45 degrees.

12. A lithium battery capacity conversion device, characterized in that: The lithium battery capacity splitting device comprises a fire extinguishing system as claimed in any one of claims 7 to 11.

13. The lithium battery capacity conversion device according to claim 12, characterized in that: The lithium battery capacity conversion device comprises a plurality of storage locations, the energy storage structure comprises a lithium battery, the lithium battery is arranged in the storage location, and each of the storage locations is provided with at least one group of corresponding liquid nitrogen nozzles and fire extinguishing agent nozzles.

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