Lithium battery fire prevention device and method

Abstract

The application discloses a lithium battery fire prevention and control device and method, and relates to the technical field of lithium battery safety protection and fire fighting. The lithium battery fire prevention and control device comprises a main nozzle, a plurality of auxiliary nozzles, a double-medium supply system and a control module. The main nozzle is used for spraying fire extinguishing medium to a target prevention and control area, and the auxiliary nozzles are used for spraying cooling medium. The auxiliary nozzles corresponding to the target prevention and control area are arranged at predetermined positions and have predetermined spraying directions, so that the auxiliary jet flow and the induced airflow form a local regulation flow field in the target prevention and control area and the periphery thereof. The main jet flow formed by the main nozzle is directed towards the target prevention and control area, and the propagation path of the main jet flow is at least partially located in the action range of the local regulation flow field. Thus, the flow environment formed by the auxiliary nozzles can be used to regulate the transportation of the fire extinguishing medium, and the gas flow and heat propagation generated by thermal runaway can be intervened, so that directional fire extinguishing, regional cooling and cooperative prevention and control of lithium battery fire can be realized.

Description

Technical Field

[0001] This invention relates to the field of lithium battery safety protection and fire protection technology, and in particular to a lithium battery fire prevention and control device and method. Background Technology

[0002] With the rapid development of new energy vehicles, rail transit, electrochemical energy storage, and various electric equipment, lithium-ion batteries have been widely used. Lithium-ion batteries are characterized by high energy density and good cycle performance, but they may experience thermal runaway under abnormal operating conditions such as overcharging, internal short circuits, external heating, or mechanical damage. Thermal runaway is typically accompanied by rapid temperature increases, release of flammable gases, pressure relief and ejection, and open flames. Furthermore, in relatively confined spaces such as battery packs, battery cabinets, and energy storage containers, the high-temperature airflow and flames generated by thermal runaway can further complicate the fire's development. Therefore, appropriate fire prevention and control devices are needed to promptly address abnormal battery areas.

[0003] Existing lithium battery fire prevention devices typically use sprinklers to spray fire extinguishing agents into abnormal areas to extinguish fires or cool them down. Depending on the fire extinguishing agent and prevention requirements, one or more sprinklers can be installed, and fire extinguishing agents, cooling agents, or combinations of different types of fire extinguishing agents can be used. When multiple sprinklers are working together, the jets generated by each sprinkler will propagate within a confined space and are affected by the high-temperature airflow generated by thermal runaway, the depressurization airflow, and the surrounding spatial boundaries. Therefore, the actual propagation state of the fire extinguishing agent in the space has strong flow coupling characteristics.

[0004] Existing jet fire control devices typically arrange nozzles primarily based on the spray coverage area and the supply of fire-fighting media, without adequately considering the interactions between different jets and between the jets and the surrounding gas flow. Consequently, it is difficult to actively control the propagation and diffusion of the fire-fighting media toward the target control area, which can easily cause some of the fire-fighting media to deviate from the area that needs to be treated, thus affecting the effective role of the fire-fighting media within the target control area.

[0005] Therefore, there are still shortcomings and deficiencies in the existing technology, and there is an urgent need in this field for a new lithium battery fire prevention and control technology. Summary of the Invention

[0006] The purpose of this invention is to provide a lithium battery fire prevention and control device and method to improve the transport status of fire extinguishing media in the target prevention and control area and enhance the effectiveness of the fire extinguishing media in the target prevention and control area.

[0007] To achieve the above objectives, the present invention provides a lithium battery fire prevention device, comprising: The main nozzle is used to spray fire extinguishing medium toward the target control area of ​​the lithium battery; Multiple auxiliary nozzles are arranged within the control space where the lithium battery is located, for spraying cooling medium into the space where the target control area is located; A dual-media supply system, connected to the main nozzle and the auxiliary nozzle, is used to provide at least a fire extinguishing medium to the main nozzle and a cooling medium to the auxiliary nozzle; The control module is used to acquire state information characterizing the thermal runaway state and location of the lithium battery, and to control the main nozzle, at least some of the auxiliary nozzles corresponding to the target control area, and the dual-medium supply system according to the state information. The arrangement position and spray direction of the auxiliary nozzles corresponding to the target control area are configured to form a local controlled flow field in the target control area and / or around the target control area, with the auxiliary jet stream formed by the auxiliary nozzles and the airflow induced by the auxiliary jet stream forming the auxiliary jet stream. The main nozzle can be adjusted so that the main jet stream formed by the main nozzle is directed toward the target control area, and the propagation path of the main jet stream is at least partially within the range of the local controlled flow field.

[0008] In some technical solutions, a plurality of auxiliary nozzles are arranged circumferentially around the main nozzle, and at least some of the auxiliary nozzles have a tangential component in their spray axis relative to the radial direction toward the target control area, so that the auxiliary jet stream formed by the plurality of auxiliary nozzles forms at least one of an inwardly converging flow and a circumferentially rotating flow in the target control area; the main jet stream formed by the main nozzle is at least partially located within the area of ​​action defined by the inwardly converging flow and / or the circumferentially rotating flow.

[0009] In some technical solutions, there are 3 to 8 auxiliary nozzles, and the angle between the spray axis of each auxiliary nozzle and the bearing plane of the battery module is 15° to 60°.

[0010] In some technical solutions, the main nozzle is connected to an attitude adjustment mechanism, which is used to adjust the azimuth and pitch angles of the main nozzle so that the main nozzle changes the spray direction according to the thermal runaway position.

[0011] In some technical solutions, the control space is divided into multiple control zones, and multiple auxiliary nozzles are distributed in different control zones. The auxiliary nozzles corresponding to each control zone can be independently controlled in terms of spraying state and / or spraying flow rate. The main nozzle is mounted on a moving mechanism, which is used to drive the main nozzle to move along a preset moving path to different control zones. The main nozzle is also connected to a steering mechanism for adjusting its spray direction. The control module is configured to determine the target control zone where thermal runaway has occurred based on the status information, activate the auxiliary nozzle corresponding to the target control zone, and control the moving mechanism and the steering mechanism to move the main nozzle to the spray position corresponding to the target control zone and toward the target control area.

[0012] In some technical solutions, the control module is also configured to acquire the temperature status of at least one adjacent control zone adjacent to the target control zone; When the adjacent control zones meet the preset heat propagation linkage conditions, the control module activates the secondary nozzles corresponding to the adjacent control zones, so that the secondary nozzles corresponding to the target control zone and the secondary nozzles corresponding to the adjacent control zones work together to expand the range of the local control flow field and suppress the propagation of heat to the adjacent control zones.

[0013] In some technical solutions, the dual-media supply system includes a fire extinguishing medium storage unit, a cooling medium storage unit, a medium delivery pipeline, and a valve control assembly installed on the medium delivery pipeline; The fire extinguishing medium storage unit is selectively connected to the main nozzle via a fire extinguishing medium supply branch; the cooling medium storage unit is connected to the auxiliary nozzle via a cooling medium supply branch and is selectively connected to the main nozzle; the control module controls the valve control assembly to enable the main nozzle to switch between spraying the fire extinguishing medium and spraying the cooling medium.

[0014] In some technical solutions, the status information includes at least two of the following: battery temperature, temperature rise rate, combustible gas concentration, pressure relief state, and flame state; the control module is configured to determine whether the lithium battery is in the early stage of thermal runaway, the pressure relief stage, the open flame stage, or the reignition suppression stage based on the status information, and to change the injection medium of the main nozzle, as well as the injection state and / or injection flow rate of the main nozzle and / or the auxiliary nozzle, according to the determined stage.

[0015] The present invention also provides a method for preventing lithium battery fires, comprising: Determine the target control area based on the lithium battery status information; The auxiliary nozzles corresponding to the target control area are controlled to spray cooling medium to form a localized flow field in the target control area; When the fire extinguishing triggering conditions are met, the main nozzle is controlled to spray the fire extinguishing medium toward the target control area, and the auxiliary nozzle is maintained to spray the cooling medium for at least a portion of the time during which the main nozzle sprays the fire extinguishing medium, so that the main jet of the fire extinguishing medium passes through the local controlled flow field at least in part, and the local controlled flow field is used to guide and / or constrain the transport of the fire extinguishing medium toward the target control area.

[0016] In some technical solutions, the auxiliary nozzle is activated to spray the cooling medium before the fire extinguishing triggering condition is met; When the fire extinguishing triggering condition is met, the auxiliary nozzle continues to spray the cooling medium and the main nozzle is activated to spray the fire extinguishing medium. When the fire extinguishing triggering condition disappears and the target control area still meets the continuous cooling condition, the main nozzle stops spraying the fire extinguishing medium and switches to spraying the cooling medium to work in conjunction with the auxiliary nozzle to cool the target control area.

[0017] Compared with the above-mentioned background technology, the lithium battery fire prevention device provided by the present invention has at least the following beneficial effects: By setting up a main nozzle for directional spraying of fire extinguishing medium and multiple auxiliary nozzles for spraying cooling medium, the fire extinguishing and cooling effects are undertaken by spraying units with different functions. This is beneficial for concentrating the fire extinguishing medium on the target control area based on the location of the lithium battery thermal runaway zone, while using the auxiliary nozzles to cool the target area and its surrounding space.

[0018] By adjusting the placement and direction of the secondary nozzles, the auxiliary jets generated by the secondary nozzles and the airflow induced by the auxiliary jets form a locally regulated flow field in and around the target control area. Compared with simply increasing the spray coverage, this locally regulated flow field can actively change the gas movement state around the target area, which is beneficial for intervening in the high-temperature airflow, thermal plume, and combustible gas migration process generated during lithium battery thermal runaway.

[0019] The main jet stream generated by the main nozzle is directed toward the target control area, and the propagation path of the main jet stream is at least partially within the range of the local controlled flow field. This allows the flow environment formed by the secondary nozzle to act on the extinguishing medium sprayed by the main nozzle, which helps to guide or limit the diffusion of the extinguishing medium in space, reduce the ineffective diffusion of the extinguishing medium to non-target areas, and improve the effectiveness of the extinguishing medium within the target control area. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a lithium battery fire prevention and control device using a surround-type auxiliary nozzle and an adjustable main nozzle in one embodiment of the present invention. Figure 2 This is a schematic diagram of a lithium battery fire prevention device that employs partitioned auxiliary sprinklers and a movable main sprinkler in another embodiment of the present invention.

[0022] Figures 1 to 2 The attached diagram is labeled as follows: 1. Main nozzle; 2. Secondary nozzle; 3. Dual media supply system; 4. Control module; 5. Battery module. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] In this specification, the term "target control area" refers to the spatial area requiring fire suppression and / or cooling protection, determined based on the operating state, abnormal state, or thermal runaway location of the lithium battery. This area can correspond to a single battery cell, a single battery module 5, or the local space containing multiple adjacent battery cells or battery modules 5. The term "local controlled flow field" refers to the flow region formed by the auxiliary jet stream created by the cooling medium sprayed from the secondary nozzle 2, and the entrainment, pushing, and disturbance of the surrounding gas by the auxiliary jet stream, which can alter the gas movement state within the target control area. Depending on the arrangement and spray direction of the secondary nozzle 2, the local controlled flow field can manifest as a converging flow, a rotating flow, a transverse disturbance flow, or a combination of these flow forms. The term "main jet stream" refers to the medium jet formed by the extinguishing medium sprayed from the main nozzle 1. By ensuring that at least a portion of the main jet stream's propagation path is within the effective range of the local controlled flow field, the diffusion direction and range of the main jet stream can be controlled using the auxiliary jet stream formed by the secondary nozzle 2 and its induced airflow.

[0026] like Figure 1 and Figure 2 As shown, this embodiment provides a lithium battery fire prevention and control device, including a main nozzle 1, multiple auxiliary nozzles 2, a dual-medium supply system 3, and a control module 4.

[0027] The main nozzle 1 is used to spray fire extinguishing medium toward the target control area of ​​the lithium battery. The main nozzle 1 can be set above or to the side of the battery module 5. The spray direction of the main nozzle 1 can be adjusted according to the location of the target control area, so that the main jet stream is directed toward the abnormal or thermally runaway battery cell, battery module 5, or corresponding local space.

[0028] Multiple auxiliary nozzles 2 are arranged within the control space where the battery module 5 is located, and are used to spray cooling medium into the space where the target control area is located. Each auxiliary nozzle 2 is not only used to increase the coverage area of ​​the cooling medium, but also, through the coordination of its arrangement and spray direction, to make the auxiliary jets formed by at least some of the auxiliary nozzles 2 superimpose in the target control area and its surroundings, and to form a localized controlled flow field through the entrainment effect of the auxiliary jets on the surrounding air.

[0029] The dual-media supply system 3 has at least the functions of supplying extinguishing media and cooling media, wherein the extinguishing media can be delivered to the main nozzle 1 and the cooling media can be delivered to the auxiliary nozzle 2. Depending on different operating conditions, the dual-media supply system 3 can also deliver cooling media to the main nozzle 1.

[0030] The control module 4 establishes a control connection with the main sprinkler head 1, the auxiliary sprinkler head 2, and the dual-medium supply system 3. The control module 4 can acquire status information characterizing the battery's thermal runaway state and location. This status information can be acquired by sensors installed in this device, or through a communication interface from the battery management system, fire monitoring system, or other external monitoring equipment.

[0031] Once the control module 4 determines the target control area based on the status information, it controls the auxiliary nozzle 2 corresponding to the target control area to spray. The auxiliary jet formed by the auxiliary nozzle 2 disturbs the high-temperature gas and combustible gas near the target control area, changing the propagation direction of the thermal plume generated by thermal runaway and promoting the dilution or migration of local combustible gas; on the other hand, it creates a local flow environment that regulates the main jet.

[0032] The main nozzle 1 is adjusted to face the target control area, ensuring that at least a portion of the main jet's propagation path enters the effective range of the localized controlled flow field. While the main nozzle 1 is spraying the extinguishing medium, the auxiliary nozzle 2 can maintain the spraying of the cooling medium, ensuring the continuous existence of the localized controlled flow field. Thus, the auxiliary jet and its induced airflow can limit the excessive diffusion of the main jet away from the target control area and / or promote the transport of the main jet towards the target control area, thereby enhancing the effectiveness of the extinguishing medium within the target control area.

[0033] In some embodiments, such as Figure 1 As shown, this embodiment provides a surround nozzle arrangement structure suitable for compact spaces such as battery packs.

[0034] Multiple auxiliary nozzles 2 are arranged circumferentially around the main nozzle 1. The main nozzle 1 is located in the center or near the center of the area enclosed by the multiple auxiliary nozzles 2, and each auxiliary nozzle 2 is set towards the target control area where the battery module 5 is located.

[0035] At least some of the auxiliary nozzles 2 have a tangential component in their spray axis relative to the radial direction from the location of the auxiliary nozzle 2 toward the target control area. That is, the spray direction of the corresponding auxiliary nozzle 2 is not directly pointing to the target control area in the radial direction, but has a velocity component extending circumferentially along the target control area while moving toward the target control area.

[0036] When multiple auxiliary nozzles 2 spray cooling medium simultaneously, their auxiliary jets can form a flow that converges towards the target control area above or around the target control area, a flow that rotates circumferentially along the target control area, or a combination of both.

[0037] When the converging flow is formed, the auxiliary jets from different directions act from the periphery of the target control area inward, which can constrain the main jet formed by the main nozzle 1 to concentrate towards the target area, reducing the ineffective diffusion of the extinguishing medium into the outer space.

[0038] When a rotating flow is formed, the locally controlled flow field can create a gas flow with a circumferential velocity component around the propagation region of the main jet. This flow can, on the one hand, disturb the rising thermal plume formed by the thermal runaway of the battery, and on the other hand, change the flow boundary conditions around the main jet, thereby increasing the contact time of the extinguishing medium near the target control area.

[0039] This embodiment is particularly suitable for battery packs with small internal space dimensions and short distances between the main nozzle 1 and each battery cell. In this application scenario, by arranging the auxiliary nozzles 2 in a surrounding manner, a relatively stable localized flow field can be formed in a small space using a limited number of nozzles.

[0040] In some embodiments, there are 3 to 8 auxiliary nozzles 2, which are distributed at intervals around the main nozzle 1. The specific number of auxiliary nozzles 2 can be determined according to the size of the battery module 5, the volume of the control space, and the coverage requirements of the target control area.

[0041] Taking a structure with four auxiliary nozzles 2 as an example, the four auxiliary nozzles 2 can be evenly arranged around the main nozzle 1 and spray towards the target control area respectively. For structures with six or eight auxiliary nozzles 2, the continuity of the local controlled flow field around the target control area can be improved by increasing the spatial distribution direction of the auxiliary jets.

[0042] Each auxiliary nozzle 2 is positioned at an angle of 15° to 60° toward the target control area. In this embodiment, the aforementioned angle is the angle formed between the spray axis of the auxiliary nozzle 2 and the plane containing the upper surface of the battery module 5. In practical applications, a corresponding reference plane can also be established based on the installation direction of the device.

[0043] In some embodiments, such as Figure 1 As shown, the main nozzle 1 is connected to an attitude adjustment mechanism. The attitude adjustment mechanism may include an azimuth adjustment mechanism for changing the horizontal orientation of the main nozzle 1 and a pitch adjustment mechanism for changing the vertical tilt angle of the main nozzle 1.

[0044] The orientation adjustment mechanism can be a rotating support, a motor-driven rotating structure, or other structures that enable the main nozzle 1 to rotate around a predetermined axis; the pitch adjustment mechanism can be a rotating shaft, a swing bracket, or other angle adjustment mechanism.

[0045] After determining the location of thermal runaway, the control module 4 generates corresponding attitude control commands based on the spatial position of the target control area relative to the main nozzle 1, and controls the attitude adjustment mechanism to adjust the azimuth and pitch angles of the main nozzle 1 so that the spray axis of the main nozzle 1 points to the target control area.

[0046] The direction adjustment of the main nozzle 1 can be completed before spraying the extinguishing medium, or it can be dynamically adjusted according to the position changes of the target control area during the spraying process.

[0047] For thermal runaway occurring at different locations within the same battery pack, since the secondary nozzle 2 has already established a localized flow field around the target control area, the main nozzle 1 only needs to adjust the spray direction according to the location of the thermal runaway to allow the main jet stream formed to enter the effective range of the localized flow field, thereby achieving directional fire suppression.

[0048] By setting an attitude adjustment mechanism, the effective coverage range of the main nozzle 1 can be expanded without increasing the number of main nozzles 1, and the spatial matching degree between the main jet flow and the target control area and the local control flow field can be improved.

[0049] In some embodiments, such as Figure 2 As shown, this embodiment provides a zoned fire prevention and control structure suitable for battery cabinets, energy storage containers, or other larger fire prevention and control spaces.

[0050] In this embodiment, the control space where the battery module 5 is located is divided into multiple control zones according to the spatial arrangement of the battery module 5. Each control zone is equipped with one or more auxiliary nozzles 2, and the auxiliary nozzles 2 corresponding to different control zones can independently control the spraying state and / or spraying flow rate.

[0051] Each control zone's corresponding auxiliary nozzle 2 is connected to the dual-medium supply system 3 via an independent valve-controlled branch. When no abnormality occurs in one of the control zones, the corresponding auxiliary nozzle 2 can remain closed; when the control module 4 determines that the battery in a certain control zone is abnormal or thermally runaway, it will only prioritize activating the auxiliary nozzle 2 corresponding to that control zone to establish a localized controlled flow field within the target control area.

[0052] The main nozzle 1 is mounted on a moving mechanism. The moving mechanism includes a preset moving path arranged along the arrangement direction of the battery modules 5 and a drive structure for driving the main nozzle 1 to move along the moving path. The preset moving path can be formed by a guide rail, a slide rail, or other guiding structure.

[0053] The main nozzle 1 is also connected to a steering mechanism. When the control module 4 determines the target prevention and control zone where thermal runaway has occurred, it controls the moving mechanism to move the main nozzle 1 to the position corresponding to the target prevention and control zone, and adjusts the spray direction of the main nozzle 1 through the steering mechanism so that the main nozzle 1 is facing the specific target prevention and control area.

[0054] Compared to deploying a large number of main sprinklers throughout a large space, this embodiment uses a combination of mobile main sprinklers 1 and zoned fixed auxiliary sprinklers 2. This allows one or fewer main sprinklers 1 to cover multiple control zones, while only activating auxiliary sprinklers 2 near abnormal areas, thereby achieving precise local control.

[0055] In some embodiments, in addition to acquiring the status information of the target prevention and control zone, the control module 4 also acquires the temperature status of at least one prevention and control zone adjacent to the target prevention and control zone.

[0056] The aforementioned temperature status may include the real-time temperature of batteries within adjacent control zones, temperature change trends, or other temperature parameters that reflect the degree of heating in adjacent areas. Control module 4 determines whether there is a risk of heat generated in the target control zone spreading further to adjacent control zones based on preset heat propagation linkage conditions. When adjacent control zones have not yet met the heat propagation linkage conditions, only the auxiliary nozzle 2 corresponding to the target control zone remains operational to limit the cooling medium consumption range. When adjacent control zones meet the heat propagation linkage conditions, control module 4 activates the auxiliary nozzle 2 corresponding to the adjacent control zone, causing the adjacent control zone to generate new auxiliary jets. At this time, the auxiliary jets corresponding to the target control zone and the auxiliary jets corresponding to the adjacent control zones work together to extend the localized control flow field that originally mainly covered the target control zone to adjacent areas. The extended flow field can form a cooling and gas flow intervention zone between the target control zone and adjacent control zones, thereby reducing the risk of further heating of adjacent batteries caused by thermal plumes, high-temperature gases, and thermal radiation.

[0057] Based on the actual spatial structure, one, two, or more adjacent prevention and control zones can be linked in sequence, thereby dynamically expanding the local prevention and control range as the risk of thermal runaway spreads, without having to activate all auxiliary nozzles 2 in the early stages of an anomaly.

[0058] In some embodiments, the dual-media supply system 3 includes a fire extinguishing media storage unit, a cooling media storage unit, a media delivery pipeline, and a valve control assembly.

[0059] The extinguishing medium storage unit stores extinguishing media suitable for rapid flame suppression and is selectively connected to the main nozzle 1 via an extinguishing medium supply branch. The cooling medium storage unit stores cooling media with a continuous cooling effect and is connected to multiple auxiliary nozzles 2 via a cooling medium supply branch. The cooling medium supply branch is also selectively connected to the main nozzle 1.

[0060] The valve control component is installed on the corresponding medium delivery pipeline and establishes a control connection with the control module 4. By changing the conduction state of the valve control component, delivery paths can be established between the fire extinguishing medium storage unit and the main nozzle 1, between the cooling medium storage unit and the auxiliary nozzle 2, and between the cooling medium storage unit and the main nozzle 1, respectively.

[0061] In the fire-extinguishing state, control module 4 controls the activation of the fire extinguishing medium supply branch, causing the main nozzle 1 to spray fire extinguishing medium, while simultaneously controlling the cooling medium supply branch to supply cooling medium to the auxiliary nozzle 2. When the open flame has been suppressed but the target control area still needs continuous cooling, control module 4 closes or cuts off the fire extinguishing medium supply path corresponding to the main nozzle 1, and connects the cooling medium storage unit to the main nozzle 1. At this time, the main nozzle 1 switches from fire extinguishing medium spraying state to cooling medium spraying state, and can work together with the auxiliary nozzle 2 to cool the target control area.

[0062] To reduce the mutual influence between different media, each media supply branch can use an independent pipeline, and check valves, shut-off valves, or switching valves can be installed as needed. The specific pipeline configurations described above do not constitute a limitation on the present invention, as long as selective switching between the extinguishing medium and the cooling medium of the main nozzle 1 can be achieved.

[0063] In this invention, the extinguishing medium and cooling medium can be selected according to the lithium battery type, the form of the controlled space, and the fire protection requirements.

[0064] In one specific embodiment, the extinguishing medium can be perfluorohexanone or heptafluoropropane. Preferably, the main nozzle 1 can use perfluorohexanone as the extinguishing medium to rapidly suppress open flames in the target control area.

[0065] The cooling medium can be fine water mist. After being sprayed out by the auxiliary nozzle 2, the fine water mist acts directly on the battery and its surrounding space and carries away heat. On the other hand, it forms an auxiliary jet with a certain momentum during the spraying process and forms a locally regulated flow field by entraining the surrounding gas.

[0066] During the open flame stage, the main nozzle 1 can spray perfluorohexanone or heptafluoropropane, while the auxiliary nozzle 2 sprays fine water mist simultaneously. During the reignition suppression stage, the main nozzle 1 can switch from extinguishing medium to fine water mist and work together with the auxiliary nozzle 2 for cooling.

[0067] The fire extinguishing and cooling media mentioned above are only specific examples. If the corresponding fire extinguishing and cooling functions can be achieved, other fire-fighting media suitable for lithium battery fire prevention and control can also be selected according to application requirements.

[0068] In some embodiments, the status information acquired by the control module 4 includes at least two of the following: battery temperature, temperature rise rate, combustible gas concentration, pressure relief status, and flame status.

[0069] Based on the above status information, the control module 4 can divide the abnormal development process of the lithium battery into the early stage of thermal runaway, the depressurization stage, the open flame stage, and the reignition suppression stage, and change the injection medium of the main nozzle 1, as well as the injection state and / or injection flow rate of the main nozzle 1 and / or the auxiliary nozzle 2 according to the determined stage.

[0070] In the early stages of thermal runaway, the battery has already experienced an abnormal temperature rise, but no significant pressure relief or open flame has yet formed. Control module 4 can prioritize activating the auxiliary nozzle 2 corresponding to the target control area, causing the auxiliary nozzle 2 to spray cooling medium at a relatively low spray intensity to reduce the temperature of the target control area and establish a localized flow field in advance.

[0071] During the depressurization phase, the risk of the battery releasing high-temperature gases and combustible gases increases. Control module 4 can increase the injection flow rate of the auxiliary nozzle 2 or increase the number of auxiliary nozzles 2 in operation to enhance the intervention effect of the localized flow field on the migration of combustible gases and the propagation of the thermal plume. Simultaneously, the main nozzle 1 can be adjusted to a ready-to-spray state facing the target control area.

[0072] During the open flame stage, control module 4 controls the main nozzle 1 to spray the extinguishing medium and maintains the auxiliary nozzle 2 to spray the cooling medium. At this time, the main jet enters the range of the local controlled flow field. The auxiliary jet and its induced airflow act on the thermal plume and combustible gas on the one hand, and regulate the transport of the extinguishing medium in the target control area on the other hand.

[0073] During the reignition suppression phase, the open flame has been extinguished, but the target control area remains at a high temperature. Control module 4 stops the main nozzle 1 from spraying the extinguishing medium and, based on the medium switching status of the dual-medium supply system 3, switches the main nozzle 1 to spray the cooling medium. The main nozzle 1 and the auxiliary nozzle 2 work together to continuously cool the abnormal battery and its surrounding area.

[0074] Through the above-mentioned status identification and control, the working status of the main sprinkler head 1, the auxiliary sprinkler head 2, and the dual-media supply system 3 can be changed according to the stage of fire development, thereby avoiding the use of the same spraying method in all stages.

[0075] In one specific implementation, for Figure 1 The relatively compact control space, including the battery pack shown, can be controlled by the main sprinkler head 1 and the auxiliary sprinkler head 2 according to the following parameters. It should be noted that the following parameters are used to illustrate one feasible control method and are not the only limitation on the control parameters of this invention; in actual application, adjustments can be made according to the battery capacity, the size of the battery module 5, the intensity of thermal runaway heat release, the volume of the control space, and the physical properties of the fire-fighting medium used.

[0076] In the early stage of thermal runaway, when the temperature of any single battery cell in battery module 5 exceeds 65°C and the temperature rise rate exceeds 1°C / s, and the pressure relief valve has not yet opened, it can be determined that the target control area has entered the early stage of thermal runaway. Control module 4 prioritizes activating the auxiliary nozzles 2 corresponding to the target control area to spray cooling medium, thereby pre-establishing a localized controlled flow field in the target control area. Under a specific parameter setting, the spray flow rate of each auxiliary nozzle 2 can be 0.5–1.0 L / min, and continuous spraying is maintained until the temperature rise rate of the corresponding battery decreases to below 0.5°C / s or the next fire development stage begins. During this stage, the main nozzle 1 can remain in standby mode and pre-adjust its spray posture towards the target control area.

[0077] During the pressure relief phase, thermal runaway can be determined to have entered the pressure relief phase when at least one of the following conditions is detected: the battery pressure relief valve is open, the combustible gas concentration exceeds 2000 ppm, and the battery surface temperature exceeds 100°C. Control module 4 increases the cooling medium injection intensity of the auxiliary nozzles 2. Under a specific parameter setting, the injection flow rate of each auxiliary nozzle 2 can be increased to 2.0–3.5 L / min, and continuous injection is performed; the main nozzle 1 remains in a ready-to-spray state, and the injection direction is adjusted according to the determined thermal runaway location.

[0078] During the open flame stage, when the flame sensor detects a flame signal, or when infrared thermal imaging detects a sudden rise in local temperature exceeding 400°C, the fire extinguishing trigger condition can be determined to be met. At this time, the control module 4 starts the main nozzle 1 while maintaining the spraying of cooling medium by the auxiliary nozzle 2, causing the main nozzle 1 to spray the fire extinguishing medium toward the target control area.

[0079] Under specific parameter settings, the extinguishing medium spray flow rate of the main nozzle 1 can be 5–8 L / min, and the cooling medium spray flow rate of the auxiliary nozzle 2 can be 3.0–4.5 L / min. The spray pressure of the main nozzle 1 when spraying the extinguishing medium can be 2.5 MPa, and the spraying of the extinguishing medium can be stopped after the open flame is detected to have disappeared. The auxiliary nozzle 2 continues to spray the cooling medium to maintain the local controlled flow field and the cooling effect on the target control area.

[0080] During the open flame stage described above, the main jet stream formed by the main nozzle 1 is at least partially controlled by the localized flow field formed by the auxiliary nozzle 2. By maintaining the main nozzle 1 and the auxiliary nozzle 2 operating synchronously for at least a portion of the time, the auxiliary jet stream and its induced airflow can continuously act on the main jet stream, thereby regulating the transport of the extinguishing medium to the target control area.

[0081] During the reignition suppression phase, if the open flame signal disappears and remains so for more than 5 seconds, and the battery surface temperature within the target control area is still above 80°C, it can be determined that the fire extinguishing trigger condition has disappeared, but the target control area still meets the continuous cooling condition. The control module 4 stops the main nozzle 1 from spraying the fire extinguishing medium and switches the main nozzle 1 to spray the cooling medium through the dual-medium supply system 3.

[0082] Under specific parameter settings, the flow rate of the cooling medium sprayed by the main nozzle 1 can be 2.0–3.0 L / min, and the flow rate of the cooling medium sprayed by each auxiliary nozzle 2 can be 1.5–2.5 L / min. The main nozzle 1 and auxiliary nozzle 2 can use an intermittent spraying method for continuous cooling, for example, an intermittent spraying method with a period of 20 s and a duty cycle of 0.25, to reduce the consumption of fire-fighting media.

[0083] When the temperature of battery module 5 in the target control area drops below 60°C, it can be determined that the cooling termination condition is met, and control module 4 controls the main nozzle 1 and auxiliary nozzle 2 to stop spraying cooling medium.

[0084] Therefore, in the above specific implementation, a control process can be formed in sequence: the auxiliary nozzle 2 pre-establishes a local control flow field, the main nozzle 1 and the auxiliary nozzle 2 work together to extinguish the fire, and the main nozzle 1 and the auxiliary nozzle 2 cool together after the fire is extinguished.

[0085] In another specific implementation, for Figure 2 The battery cabinets, energy storage containers, and other large-scale prevention and control spaces shown can be configured with spray parameters for each prevention and control zone.

[0086] When a battery in a certain control zone experiences abnormal temperature rise or pressure drop, only the auxiliary nozzle 2 corresponding to that target control zone can be activated. In one specific setup, each control zone can be equipped with 2 to 4 auxiliary nozzles 2, and the cooling medium injection flow rate of each auxiliary nozzle 2 can be 1 to 2 L / min, maintaining continuous injection to form a localized controlled flow field within the target control zone.

[0087] When the target control zone meets the fire extinguishing triggering conditions, the control module 4 controls the moving mechanism to move the main sprinkler head 1 to the position corresponding to the target control zone, and adjusts the spray direction of the main sprinkler head 1 through the steering mechanism. While the auxiliary sprinkler head 2 continuously sprays cooling medium, the main sprinkler head 1 is activated to spray fire extinguishing medium.

[0088] Under specific parameter settings, the extinguishing medium spray flow rate of the main nozzle 1 can be 10–15 L / min, and the cooling medium spray flow rate of each auxiliary nozzle 2 can be 5–8 L / min. The spray pressure of the main nozzle 1 can be adjusted according to the distance between the main nozzle 1 and the target control area to ensure that the extinguishing medium can reach the target control area.

[0089] When the open flame is extinguished but the target control zone still needs to continue cooling, the main nozzle 1 can be switched to spray cooling medium. Under a specific parameter setting, the cooling medium spray flow rate of the main nozzle 1 can be 5-8 L / min, and the cooling medium spray flow rate of each auxiliary nozzle 2 can be 3-5 L / min, and an intermittent spray mode with a cycle of 10 s and a duty cycle of 0.25 can be adopted.

[0090] When the temperature of battery module 5 in the target control zone drops below 60°C, it can be determined that the cooling termination condition is met, and the spraying of cooling medium from the corresponding main nozzle 1 and auxiliary nozzle 2 will stop.

[0091] Furthermore, when the battery temperature in a control zone adjacent to the target control zone exceeds 65°C, this state can be used as a heat propagation linkage condition. The control module 4 activates the auxiliary nozzle 2 corresponding to the adjacent control zone, so that the auxiliary jets corresponding to the target control zone and the adjacent control zone work together to expand the range of local flow field regulation. In addition to the lithium battery fire prevention and control devices disclosed in the above embodiments, this embodiment provides a lithium battery fire prevention and control method.

[0092] First, obtain the status information of the lithium battery, and then determine the target prevention and control area where fire prevention and control needs to be implemented based on the status information.

[0093] The target control area can be determined directly based on the spatial location of the abnormal battery, or it can be determined comprehensively based on multiple detection parameters.

[0094] After determining the target control area, the auxiliary nozzle 2 corresponding to that target control area is controlled to spray cooling medium. The auxiliary jet formed by the auxiliary nozzle 2 and the gas flow entrained by the auxiliary jet form a localized controlled flow field in the target control area.

[0095] The localized controlled flow field can be established before or when the main nozzle 1 is started, and act on the gas flow within the target control area.

[0096] When the lithium battery status meets the preset fire extinguishing trigger conditions, the main nozzle 1 is controlled to spray the fire extinguishing medium toward the target control area.

[0097] During at least a portion of the time that the main nozzle 1 sprays the extinguishing medium, at least a portion of the corresponding auxiliary nozzles 2 continue to spray the cooling medium, so that the localized controlled flow field persists during the spraying process of the main nozzle 1.

[0098] The main jet stream formed by the main nozzle 1 is at least partially controlled by the local flow field. Under the influence of the auxiliary jet stream and its induced airflow, the spatial diffusion state of the main jet stream is changed, causing the extinguishing medium to be transported more towards the target control area and / or reducing the diffusion of the extinguishing medium away from the target control area.

[0099] By using the above method, without relying solely on increasing the spray flow rate of the main nozzle 1, the flow environment formed by the auxiliary nozzle 2 can be used to improve the transport status of the extinguishing medium in the target area.

[0100] The following section provides further explanation of the activation sequence of the main nozzle 1 and the auxiliary nozzle 2, as well as the cooling control method after fire extinguishing.

[0101] When the lithium battery has not yet met the fire extinguishing triggering conditions, but has already shown an abnormal state that requires preventive cooling or flow field regulation, the auxiliary nozzle 2 corresponding to the target control area is activated first to spray the cooling medium.

[0102] The secondary nozzle 2 operates in advance, enabling the establishment of a localized controlled flow field in the target control area before the formation of open flames, and pre-cooling of abnormal areas.

[0103] When the target control area meets the fire extinguishing triggering conditions, the auxiliary nozzle 2 continues to spray cooling medium, while the main nozzle 1 is activated to spray fire extinguishing medium.

[0104] Therefore, when the main nozzle 1 starts spraying, the main jet it forms directly enters the established or being established local controlled flow field, thereby avoiding the main jet from freely diffusing in a completely uncontrolled gas environment.

[0105] While the main nozzle 1 is spraying the extinguishing medium, the auxiliary nozzle 2 continues to operate to maintain the localized controlled flow field.

[0106] Once the fire extinguishing trigger condition disappears, it indicates that the open flame has been suppressed or that it is no longer necessary to continue spraying the extinguishing agent. At this point, it is necessary to further determine whether the target control area still meets the continuous cooling conditions.

[0107] When the target control area is still in a state that requires continued cooling, stop the main nozzle 1 from spraying fire extinguishing medium, and switch the main nozzle 1 to the cooling medium supply state through the dual medium supply system 3.

[0108] The main nozzle 1 and the auxiliary nozzle 2 spray cooling medium together to cool down the battery that has experienced thermal runaway and its surrounding batteries.

[0109] During the cooling process, the temperature status of the target control area can be continuously acquired. When the target control area meets the preset cooling termination conditions, the spraying of cooling medium from the main nozzle 1 and the auxiliary nozzle 2 is stopped.

[0110] This forms a continuous control process of pre-regulation of the auxiliary nozzle, coordinated fire suppression by the main and auxiliary nozzles, and coordinated cooling by the main and auxiliary nozzles. While rapidly suppressing open flames, it further controls the risk of reignition caused by continuous heat release inside the battery.

[0111] In this embodiment, the fire extinguishing trigger condition, the continuous cooling condition, and the cooling termination condition can be set based on the state information of the lithium battery.

[0112] In one specific implementation, when a flame signal is detected by a flame sensor, or when a sudden rise in local temperature in the target control area is detected by infrared thermal imaging and exceeds 400°C, it can be determined that the fire extinguishing triggering conditions are met.

[0113] When the flame signal disappears and remains so for more than 5 seconds, while the surface temperature of the battery within the target control area is still above 80°C, it can be determined that the fire extinguishing trigger condition has disappeared and the target control area still meets the continuous cooling condition. At this time, the main nozzle 1 stops spraying the fire extinguishing medium and switches to spraying the cooling medium, working together with the auxiliary nozzle 2 for continuous cooling.

[0114] When the temperature of battery module 5 in the target control area drops below 60°C, it can be determined that the cooling termination condition is met, and the corresponding cooling medium injection will stop.

[0115] It should be noted that the above-described fire extinguishing triggering conditions, continuous cooling conditions, and cooling termination conditions are one specific implementation method. In other implementation methods, the corresponding judgment parameters and thresholds can be adaptively set according to the battery type, battery capacity, allowable operating temperature, control space structure, and detection equipment type.

[0116] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0117] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A lithium battery fire prevention and control device, characterized in that, include: The main nozzle (1) is used to spray fire extinguishing medium toward the target control area of ​​the lithium battery; Multiple auxiliary nozzles (2) are arranged in the control space where the lithium battery is located, for spraying cooling medium into the space where the target control area is located; A dual-media supply system (3) is connected to the main nozzle (1) and the auxiliary nozzle (2), and is used at least to provide fire extinguishing medium to the main nozzle (1) and cooling medium to the auxiliary nozzle (2); The control module (4) is used to acquire state information characterizing the thermal runaway state and location of the lithium battery, and to control the main nozzle (1), at least some of the auxiliary nozzles (2) corresponding to the target control area, and the dual-medium supply system (3) according to the state information. The arrangement position and spray direction of the auxiliary nozzle (2) corresponding to the target control area are configured to form a local controlled flow field in the target control area and / or around the target control area by the auxiliary jet stream formed by the auxiliary jet stream and the airflow induced by the auxiliary jet stream; the main nozzle (1) can be adjusted so that the main jet stream formed by the main nozzle (1) is directed toward the target control area, and the propagation path of the main jet stream is at least partially located within the range of action of the local controlled flow field.

2. The lithium battery fire prevention device according to claim 1, characterized in that, Multiple auxiliary nozzles (2) are arranged circumferentially around the main nozzle (1), and at least a portion of the spray axis of the auxiliary nozzles (2) has a tangential component relative to the radial direction toward the target control area, so that the auxiliary jets formed by the multiple auxiliary nozzles (2) form at least one of an inwardly converging flow and a circumferentially rotating flow in the target control area; the main jet formed by the main nozzle (1) is at least partially located within the area of ​​action defined by the inwardly converging flow and / or the circumferentially rotating flow.

3. The lithium battery fire prevention device according to claim 2, characterized in that, The number of auxiliary nozzles (2) is set to 3 to 8, and the angle between the spray axis of each auxiliary nozzle (2) and the bearing plane where the battery module (5) is located is 15° to 60°.

4. The lithium battery fire prevention device according to claim 2, characterized in that, The main nozzle (1) is connected to an attitude adjustment mechanism, which is used to adjust the azimuth and pitch angle of the main nozzle (1) so that the main nozzle (1) changes the spray direction according to the thermal runaway position.

5. The lithium battery fire prevention device according to claim 1, characterized in that, The control space is divided into multiple control zones, and multiple auxiliary nozzles (2) are distributed in different control zones. The auxiliary nozzles (2) corresponding to each control zone can be independently controlled in terms of spray state and / or spray flow rate. The main nozzle (1) is mounted on a moving mechanism, which is used to drive the main nozzle (1) to move along a preset moving path to different control zones. The main nozzle (1) is also connected to a steering mechanism for adjusting its spray direction. The control module (4) is configured to determine the target control zone where thermal runaway occurs based on the status information, activate the auxiliary nozzle (2) corresponding to the target control zone, and control the moving mechanism and the steering mechanism to move the main nozzle (1) to the spray position corresponding to the target control zone and towards the target control area.

6. The lithium battery fire prevention device according to claim 5, characterized in that, The control module (4) is also configured to acquire the temperature status of at least one adjacent control zone adjacent to the target control zone; When the adjacent control zone meets the preset heat propagation linkage condition, the control module (4) activates the auxiliary nozzle (2) corresponding to the adjacent control zone, so that the auxiliary nozzle (2) corresponding to the target control zone and the auxiliary nozzle (2) corresponding to the adjacent control zone work together to expand the range of the local control flow field and suppress the spread of heat to the adjacent control zone.

7. The lithium battery fire prevention device according to any one of claims 1 to 6, characterized in that, The dual-medium supply system (3) includes a fire extinguishing medium storage unit, a cooling medium storage unit, a medium delivery pipeline, and a valve control assembly installed on the medium delivery pipeline; The fire extinguishing medium storage unit is selectively connected to the main nozzle (1) through the fire extinguishing medium supply branch; the cooling medium storage unit is connected to the auxiliary nozzle (2) through the cooling medium supply branch and is selectively connected to the main nozzle (1); the control module (4) controls the valve control component to enable the main nozzle (1) to switch between spraying the fire extinguishing medium and spraying the cooling medium.

8. The lithium battery fire prevention device according to claim 7, characterized in that, The status information includes at least two of the following: battery temperature, temperature rise rate, combustible gas concentration, depressurization state, and flame state; the control module (4) is configured to determine whether the lithium battery is in the early stage of thermal runaway, depressurization stage, open flame stage, or reignition suppression stage based on the status information, and to change the injection medium of the main nozzle (1) and the injection state and / or injection flow rate of the main nozzle (1) and / or the auxiliary nozzle (2) according to the determined stage.

9. A method for preventing lithium battery fires, characterized in that, include: Determine the target control area based on the lithium battery status information; Control the secondary nozzle (2) corresponding to the target prevention and control area to spray cooling medium to form a localized flow field in the target prevention and control area; When the fire extinguishing triggering conditions are met, the main nozzle (1) is controlled to spray the fire extinguishing medium toward the target control area, and the auxiliary nozzle (2) is maintained to spray the cooling medium for at least a part of the time period during which the main nozzle (1) sprays the fire extinguishing medium, so that the main jet of the fire extinguishing medium is at least partially passed through the local control flow field, and the local control flow field is used to guide and / or constrain the transport of the fire extinguishing medium to the target control area.

10. The lithium battery fire prevention method according to claim 9, characterized in that, Before the fire extinguishing triggering conditions are met, the auxiliary nozzle (2) is activated to spray the cooling medium. When the fire extinguishing triggering condition is met, the auxiliary nozzle (2) continues to spray the cooling medium and the main nozzle (1) is activated to spray the fire extinguishing medium. When the fire extinguishing triggering condition disappears and the target control area still meets the continuous cooling condition, the main nozzle (1) stops spraying the fire extinguishing medium and switches the main nozzle (1) to spray the cooling medium, working together with the auxiliary nozzle (2) to cool the target control area.

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