Energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing and control method thereof

Abstract

The invention discloses an energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing. The energy storage cabinet fire extinguishing system comprises a control device, a fire extinguishing device and a nitrogen circulating device. The control device comprises a liquid nitrogen controller and detectors, the detectors comprise in-pack detectors and in-cabinet detectors, the multiple in-pack detectors are arranged in the multiple battery packs respectively, the in-cabinet detectors are arranged in the energy storage cabinet, and the detectors are used for detecting the temperature, the CO concentration, the smoke concentration and the combustible gas concentration; the detectors are connected with the liquid nitrogen controller; the fire extinguishing device comprises a liquid nitrogen storage and conversion tank and a spraying device, the liquid nitrogen storage and conversion tank is connected with the spraying device, the spraying device comprises in-pack liquid nitrogen nozzles and in-cabinet liquid nitrogen nozzles, the in-pack liquid nitrogen nozzles are arranged in the battery packs respectively, and the in-cabinet liquid nitrogen nozzles are arranged in the energy storage cabinet; the in-pack detectors are connected with and control the in-pack liquid nitrogen nozzles in the corresponding battery packs, and the in-cabinet detectors are connected with and control the in-cabinet liquid nitrogen nozzles; the liquid nitrogen controller controls the spraying device to work according to parameter information collected by the detector.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage cabinets, in particular to an energy storage cabinet fire extinguishing system based on liquid nitrogen and a control method. BACKGROUND

[0002] With the rapid development of the new energy industry, lithium battery energy storage systems are widely used in new energy stations due to their high power conversion efficiency and low loss, and are used as supporting systems for peak shaving, wind power and photovoltaic power generation fluctuation suppression. However, lithium battery energy storage is prone to thermal runaway in a short period of time when subjected to strong external forces such as impact and puncture, or when battery short circuit, overcharge and other conditions occur, which may cause fire or even explosion safety hazards.

[0003] Lithium battery fires have the characteristics of high burning temperature, fast spreading speed and easy rekindling. Traditional extinguishing agents are often difficult to effectively extinguish and are prone to rekindling. In particular, energy storage systems are usually concentrated in a closed space. Once a single battery experiences thermal runaway, it may trigger a chain reaction, causing the entire energy storage system to malfunction and causing significant economic losses.

[0004] Currently, the main fire extinguishing technologies for lithium battery energy storage systems include: · Foam fire extinguishing system: oxygen is isolated by foam coverage, but there are problems such as poor foam stability, easy destruction by high temperature, and difficult post-cleaning; · Chemical extinguishing agent such as perfluorohexanone: although it has certain extinguishing effect, it is high in cost and may be environmentally unfriendly; · Water spray system: water evaporation can absorb heat and reduce temperature, but the water consumption is large and may cause battery short circuit and secondary disaster; · Ordinary gas fire extinguishing system (such as CO2, IG541): mainly extinguishes by asphyxiation, but has limited cooling effect on lithium battery high-temperature thermal runaway.

[0005] The above-mentioned traditional fire extinguishing devices are inefficient in dealing with lithium battery fires and are difficult to effectively suppress rekindling. Therefore, it is necessary to provide an energy storage cabinet fire extinguishing system based on liquid nitrogen and a control method, which is non-toxic and harmless, can quickly absorb a large amount of heat, and can quickly reduce the oxygen concentration to achieve dual fire extinguishing. SUMMARY

[0006] The present application provides a novel energy storage cabinet fire extinguishing system based on liquid nitrogen and a control method to solve the problems and deficiencies of the prior art.

[0007] The present application solves the above technical problems by the following technical solutions: The application provides an energy storage cabinet fire extinguishing system based on liquid nitrogen, wherein a plurality of battery packs are arranged in the energy storage cabinet, and the energy storage cabinet fire extinguishing system comprises a control device, a fire extinguishing device and a nitrogen circulation device arranged in the energy storage cabinet. The control device comprises a liquid nitrogen controller and a detector, wherein the detector comprises a plurality of in-pack detectors and an in-cabinet detector, the in-pack detectors are arranged in the battery packs respectively, the in-cabinet detector is arranged in the energy storage cabinet, and the detector is used for detecting the temperature, CO concentration, smoke concentration and flammable gas concentration of the space; the detector is connected with the liquid nitrogen controller to upload the parameter information of the temperature, CO concentration, smoke concentration and flammable gas concentration collected by the detector. The fire extinguishing device comprises a liquid nitrogen storage and conversion tank and a spraying device, the liquid nitrogen storage and conversion tank is connected with the spraying device through an output pipeline, the spraying device comprises a plurality of in-pack liquid nitrogen nozzles and an in-cabinet liquid nitrogen nozzle, the in-pack liquid nitrogen nozzles are arranged in the battery packs respectively, and the in-cabinet liquid nitrogen nozzle is arranged in the energy storage cabinet. The in-pack detectors are connected with and control the in-pack liquid nitrogen nozzles in the corresponding battery packs, and the in-cabinet detector is connected with and controls the in-cabinet liquid nitrogen nozzle in the energy storage cabinet. The liquid nitrogen storage and conversion tank comprises a liquid nitrogen storage tank and a nitrogen storage tank, the liquid nitrogen storage tank and the nitrogen storage tank are connected, the liquid nitrogen stored in the liquid nitrogen storage tank and the nitrogen stored in the nitrogen storage tank can be converted with each other, and the liquid nitrogen storage tank and the nitrogen storage tank are connected with the output pipeline. The nitrogen circulation device comprises nitrogen circulation joints arranged in the battery packs, and the nitrogen circulation joints are connected with the nitrogen storage tank through a circulation pipeline, so that the nitrogen storage tank, the output pipeline, the in-pack liquid nitrogen nozzles, the battery packs, the nitrogen circulation joints and the circulation pipeline form a nitrogen circulation loop. The liquid nitrogen controller controls the spraying device to work according to the parameter information collected by the detector.

[0008] Preferably, the in-pack liquid nitrogen nozzles are arranged on one side of the battery pack, the nitrogen circulation joints are arranged on the other side of the battery pack, and the in-pack detectors are installed on the front panel of the battery pack.

[0009] Preferably, the in-cabinet detector is arranged at the top of the energy storage cabinet, and the in-cabinet liquid nitrogen nozzle is arranged at the upper part of the energy storage cabinet and above the battery pack.

[0010] Preferably, the liquid nitrogen controller is connected with and controls the audible and visual alarm.

[0011] Preferably, the liquid nitrogen controller is connected to the detector through a CAN bus or a RS485 bus, and the liquid nitrogen controller is connected to a fire control center.

[0012] Based on the same concept, the application also provides a control method of the liquid nitrogen fire extinguishing based energy storage cabinet fire extinguishing system, comprising the following steps: The liquid nitrogen controller acquires the parameter information of temperature, CO concentration, smoke concentration and flammable gas concentration collected by the detector; When the values of all parameters collected by all detectors are lower than the first warning value, the energy storage cabinet is in a normal working state, and the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray nitrogen into the battery pack at a first frequency to assist heat dissipation. When the value of any parameter collected by any detector is higher than the first warning value and lower than the second warning value, the liquid nitrogen controller starts an audible and light alarm and sends a first-level warning signal; if the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray nitrogen into the battery pack at a second frequency; if the detector is an in-cabinet detector, the in-cabinet detector controls the in-cabinet liquid nitrogen nozzle to spray nitrogen into the cabinet at the second frequency. When the value of any parameter collected by any detector is higher than the second warning value and lower than the third warning value, the liquid nitrogen controller starts an audible and light alarm and sends a second-level warning signal; if the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray nitrogen into the battery pack at a third frequency; if the detector is an in-cabinet detector, the in-cabinet detector controls the in-cabinet liquid nitrogen nozzle to spray nitrogen into the cabinet at the third frequency. When the value of any parameter collected by any detector is higher than the third warning value, the liquid nitrogen controller starts an audible and light alarm and sends a third-level warning signal; if the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray liquid nitrogen into the battery pack at a fourth frequency; if the detector is an in-cabinet detector, the in-cabinet detector controls the in-cabinet liquid nitrogen nozzle to continuously spray liquid nitrogen into the cabinet; until the values of all parameters collected by the detector are lower than the third warning value.

[0013] Preferably, when the values of all parameters collected by the detector are lower than the third warning value after the liquid nitrogen controller sends a third-level warning signal and the spraying device sprays liquid nitrogen, the method further comprises the following steps: if the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray liquid nitrogen into the battery pack at a fifth frequency within a set time; if the detector is an in-cabinet detector, the in-cabinet detector controls the in-cabinet liquid nitrogen nozzle to spray liquid nitrogen into the cabinet at the fifth frequency within a set time.

[0014] Preferably, the first, second and third early warning values increase in turn, the first, second and third frequencies increase in turn, and the fourth frequency is greater than the fifth frequency.

[0015] Preferably, the liquid nitrogen storage conversion tank stores liquid nitrogen, and when the nitrogen gas storage tank sprays nitrogen gas through the spraying device and the pressure in the nitrogen gas storage tank is lower than a set value, the stored liquid nitrogen is delivered to the nitrogen gas storage tank to be converted into nitrogen gas; the nitrogen gas storage tank sprays liquid nitrogen through the spraying device, and when the pressure in the liquid nitrogen storage tank is lower than a set value, the stored nitrogen gas is delivered to the liquid nitrogen storage tank to be converted into liquid nitrogen.

[0016] The positive progress effect of the present application is that: The energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing and the control method provided by the present application have the following advantages: multi-stage early warning and precise fire extinguishing, a multi-sensor fusion detector is used to collect multiple data to realize early warning of fire, and a partition control spraying device is used to realize precise cooling and inertization of suspicious battery packs to avoid resource waste caused by "full flooding" fire extinguishing; liquid nitrogen is sprayed to extinguish fire, liquid nitrogen is used to quickly absorb heat of the battery due to its extremely low temperature, nitrogen gas is formed after gasification to form an inert environment, oxygen is isolated, and dual fire extinguishing effects of cooling and asphyxiation are realized; the functions of monitoring, early warning, intervention, alarm, explosion suppression and fire extinguishing are integrated, automatic operation is realized, and the reliability of the system is greatly improved; environmental protection and economy, liquid nitrogen is obtained from air, the source is wide, there is no residue after fire extinguishing, and the environment is friendly.

[0017] Further, liquid nitrogen is continuously sprayed for a set time after fire extinguishing to automatically maintain a low-temperature environment to prevent rekindling, ensure that the thermal runaway lithium battery does not rekindle, and solve the problem of easy rekindling of lithium battery fire.

[0018] Further, a liquid nitrogen storage conversion tank is used, nitrogen gas and liquid nitrogen can be converted into each other, the nitrogen gas storage tank can be used for cooling of the battery cluster during normal operation, and is converted into liquid nitrogen for fire extinguishing during fire extinguishing, thereby improving system efficiency and resource utilization rate. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a structural schematic diagram of an energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing according to an embodiment of the present application; Figure 2 FIG. 2 is an electrical schematic diagram of the energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing according to the embodiment of the present application; Figure 3 FIG. 3 is a control method flowchart of the energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing according to the embodiment of the present application.

[0020] In the drawings: 100-energy storage cabinet; 110-battery pack; 1 - Liquid nitrogen controller; 2 - Detector; 21 - In-pack detector; 22 - In-cabinet detector; 3 - Liquid nitrogen storage conversion tank; 31 - Output pipeline; 32 - Circulation pipeline; 4 - Injection device; 41 - In-pack liquid nitrogen nozzle; 42 - In-cabinet liquid nitrogen nozzle; 5 - Nitrogen circulation joint; 6 - Acousto-optic alarm. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0022] Please refer to Figure 1 and Figure 2 The present embodiment provides a kind of energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing, multiple battery packs 110 are provided in energy storage cabinet 100, including being provided in control device, fire extinguishing device and nitrogen circulation device in energy storage cabinet 100.

[0023] Control device includes liquid nitrogen controller 1 and detector 2, detector 2 includes multiple in-pack detectors 21 and one in-cabinet detector 22, multiple in-pack detectors 21 are respectively arranged in multiple battery packs 110, in-cabinet detector 22 is arranged in energy storage cabinet 100, and detector 2 is used to detect the temperature, CO concentration, smoke concentration and flammable gas concentration of the space;Detector 2 is connected with liquid nitrogen controller 1 to upload the temperature, CO concentration, smoke concentration and flammable gas concentration parameter information collected.

[0024] Fire extinguishing device includes liquid nitrogen storage conversion tank 3 and injection device 4, liquid nitrogen storage conversion tank 3 is connected with injection device 4 by output pipeline 31, injection device 4 includes multiple in-pack liquid nitrogen nozzles 41 and one in-cabinet liquid nitrogen nozzle 42, in-pack liquid nitrogen nozzles 41 are respectively arranged in battery pack 110, and in-cabinet liquid nitrogen nozzle 42 is arranged in energy storage cabinet 100.

[0025] In-pack detector 21 is connected with and controls in-pack liquid nitrogen nozzle 41 in corresponding battery pack 110, and in-cabinet detector 22 is connected with and controls in-cabinet liquid nitrogen nozzle 42 in energy storage cabinet 100.

[0026] Liquid nitrogen storage conversion tank 3 includes liquid nitrogen storage tank (not shown) and nitrogen storage tank (not shown), liquid nitrogen storage tank and nitrogen storage tank are connected, and liquid nitrogen stored in liquid nitrogen storage tank and nitrogen stored in nitrogen storage tank can be converted with each other;Liquid nitrogen storage tank and nitrogen storage tank are connected with output pipeline 31.

[0027] The nitrogen circulation device comprises a nitrogen circulation joint 5 arranged in the plurality of battery packs 110, the nitrogen circulation joint 5 is connected with a nitrogen storage tank through a circulation pipeline 32, and the nitrogen storage tank, an output pipeline 31, the in-pack liquid nitrogen nozzle 41, the battery pack 110, the nitrogen circulation joint 5 and the circulation pipeline 32 form a nitrogen circulation loop; the circulation utilization of nitrogen is realized, and the dual functions of heat dissipation during normal operation of the battery pack 110 and creation of an inert environment during a fire are realized.

[0028] The liquid nitrogen controller 1 controls the spraying device 4 to work according to the parameter information collected by the detector 2.

[0029] Specifically, the outlet end of the liquid nitrogen storage tank (not shown) and the outlet end of the nitrogen storage tank (not shown) can be provided with control valves, and the delivery of liquid nitrogen or nitrogen is controlled by controlling the opening and closing of the control valves.

[0030] Specifically, the liquid nitrogen storage tank is connected with an external nitrogen making device; the liquid nitrogen storage tank adopts a self-pressurization design, and liquid nitrogen can be rapidly delivered without external power.

[0031] In some embodiments, the in-pack liquid nitrogen nozzle 41 is arranged at one side in the battery pack 110, the nitrogen circulation joint 5 is arranged at the other side in the battery pack 110, and the in-pack detector 21 is installed on the front panel of the battery pack 110.

[0032] In some embodiments, the in-cabinet detector 22 is arranged at the top in the energy storage cabinet 100, and the in-cabinet liquid nitrogen nozzle 42 is arranged at the upper part in the energy storage cabinet 100 and above the battery pack 110.

[0033] In some embodiments, the sound-light alarm 6 is further included, and the liquid nitrogen controller 1 is connected with and controls the sound-light alarm 6.

[0034] In some embodiments, the liquid nitrogen controller 1 is connected with and communicates with the detector 2 through a CAN bus or an RS485 bus, and the liquid nitrogen controller 1 is connected with and communicates with the fire control center.

[0035] Specifically, the liquid nitrogen controller 1 is connected with and communicates with the fire control center, realizes real-time uploading and remote control of data, and realizes remote monitoring and emergency linkage.

[0036] Please refer to Figure 3 The application further provides a control method of the energy storage cabinet fire extinguishing system based on liquid nitrogen. S1: The liquid nitrogen controller 1 acquires the parameter information of temperature, CO concentration, smoke concentration and combustible gas concentration collected by the detector 2. S2: When the values of all parameters collected by all detectors 2 are lower than the first warning value, the energy storage cabinet 100 is in a normal working state, and the in-pack detector 21 controls the in-pack liquid nitrogen nozzle 41 in the corresponding battery pack 110 to spray nitrogen into the battery pack 110 at a first frequency to assist heat dissipation; S3: When the value of any parameter collected by any detector 2 is higher than the first warning value and lower than the second warning value, the liquid nitrogen controller 1 starts the audible and visual alarm 6 and sends a first-level warning signal; if the detector 2 is the in-pack detector 21, the in-pack detector 21 controls the in-pack liquid nitrogen nozzle 41 in the corresponding battery pack 110 to spray nitrogen into the battery pack 110 at a second frequency; if the detector 2 is the in-cabinet detector 22, the in-cabinet detector 22 controls the in-cabinet liquid nitrogen nozzle 42 to spray nitrogen into the cabinet at the second frequency; an inert environment is created to delay the development of thermal runaway of the battery pack 110; S4: When the value of any parameter collected by any detector 2 is higher than the second warning value and lower than the third warning value, the liquid nitrogen controller 1 starts the audible and visual alarm 6 and sends a second-level warning signal; if the detector 2 is the in-pack detector 21, the in-pack detector 21 controls the in-pack liquid nitrogen nozzle 41 in the corresponding battery pack 110 to spray nitrogen into the battery pack 110 at a third frequency; if the detector 2 is the in-cabinet detector 22, the in-cabinet detector 22 controls the in-cabinet liquid nitrogen nozzle 22 to spray nitrogen into the cabinet at the third frequency; the environment is further inerted. S5: When the value of any parameter collected by any detector 2 is higher than the third warning value, the liquid nitrogen controller 1 starts the audible and visual alarm 6 and sends a third-level warning signal; if the detector 2 is the in-pack detector 21, the in-pack detector 21 controls the in-pack liquid nitrogen nozzle 41 in the corresponding battery pack 110 to spray liquid nitrogen into the battery pack 110 at a fourth frequency; if the detector 2 is the in-cabinet detector 22, the in-cabinet detector 22 controls the in-cabinet liquid nitrogen nozzle 42 to continuously spray liquid nitrogen into the cabinet; fire extinguishing is performed until the values of all parameters collected by the detector 2 are lower than the third warning value.

[0037] In some embodiments, after the liquid nitrogen controller 1 sends a third-level warning signal and the spraying device 4 sprays liquid nitrogen, when the values of all parameters collected by the detector 2 are lower than the third warning value, the following steps are further included: if the detector 2 is the in-pack detector 21, the in-pack detector 21 controls the in-pack liquid nitrogen nozzle 41 in the corresponding battery pack 110 to spray liquid nitrogen into the battery pack 110 at a fifth frequency for a set time; if the detector 2 is the in-cabinet detector 22, the in-cabinet detector 22 controls the in-cabinet liquid nitrogen nozzle 42 to spray liquid nitrogen into the cabinet at the fifth frequency for a set time. After extinguishing the fire, liquid nitrogen is sprayed to prevent rekindling.

[0038] In some embodiments, the first warning value, the second warning value, and the third warning value increase in turn, the first frequency, the second frequency, and the third frequency increase in turn, and the fourth frequency is greater than the fifth frequency.

[0039] In particular, the first, second and third pre-alarm values do not refer to a specific value, but to a set of values corresponding to the parameters of temperature, CO concentration, smoke concentration and flammable gas concentration.

[0040] In particular, the first, second and third frequencies are sequentially increased, so that the nitrogen in the space environment further inertizes the environment.

[0041] In some embodiments, the liquid nitrogen storage tank of the liquid nitrogen storage conversion tank 3 delivers the stored liquid nitrogen to the nitrogen storage tank to be converted into nitrogen gas when the nitrogen gas storage tank sprays nitrogen gas through the spraying device 4 and the pressure in the nitrogen gas storage tank is lower than the set value; the nitrogen gas storage tank delivers the stored nitrogen gas to the liquid nitrogen storage tank to be converted into liquid nitrogen when the liquid nitrogen storage tank sprays liquid nitrogen through the spraying device 4 and the pressure in the liquid nitrogen storage tank is lower than the set value.

[0042] The energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing and the control method provided by the application realize monitoring and early warning: the environment parameters in the battery cabinet 100 are monitored in real time through the multi-detector 2, and when any parameter exceeds the threshold value, the system enters the early warning state; initial intervention: nitrogen gas is injected into the cabinet to reduce the oxygen concentration and delay the development of battery thermal runaway during the early warning stage; fire confirmation and extinguishing: when the fire is confirmed, the liquid nitrogen fire extinguishing device is immediately started, and the spraying device 4 sprays the fire source accurately to realize rapid cooling and fire extinguishing; preventing rekindling: after the fire is extinguished, the spraying device 4 maintains a small flow of liquid nitrogen supply to maintain a low-temperature inert environment and prevent the battery from rekindling; automatic reset: after the fire is completely extinguished, it is automatically switched to the normal monitoring state.

[0043] In summary, the energy storage cabinet fire extinguishing system based on liquid nitrogen fire extinguishing and the control method provided by the application realize multi-stage early warning and accurate fire extinguishing, use the multi-sensor fusion detector 2 to collect multiple data to realize early warning of fire, and use the partition-controlled spraying device 4 to realize accurate cooling and inertization of the suspected battery pack 110 to inhibit combustion and avoid resource waste caused by "full flooding" fire extinguishing; the liquid nitrogen spraying method is used for fire extinguishing, liquid nitrogen is used to quickly absorb the heat of the battery due to its extremely low temperature, and nitrogen gas is formed after gasification to inert the environment and isolate oxygen, realizing the dual effects of cooling and asphyxiation; the functions of "monitoring, early warning, intervention, alarm, explosion suppression and fire extinguishing" are integrated into one, realizing fully automated operation and greatly improving the reliability of the system; environmentally friendly and economical, liquid nitrogen is obtained from air, the source is extensive, there is no residue after fire extinguishing, and it is friendly to the environment.

[0044] Further, liquid nitrogen is continuously sprayed for a set time after fire extinguishing to automatically maintain a low-temperature environment to prevent rekindling, ensuring that the thermal runaway lithium battery does not rekindle, and solving the problem of easy rekindling of lithium battery fire.

[0045] Further, the conversion tank 3 is stored with liquid nitrogen, nitrogen and liquid nitrogen can be converted with each other, nitrogen storage tank can be used for normal operation of the battery cluster cooling, and when the fire is extinguished, it is converted into liquid nitrogen fire extinguishing, which improves the system efficiency and resource utilization.

[0046] Although the specific embodiments of the present application are described above, those skilled in the art should understand that these are only illustrative, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, and these changes and modifications all fall within the protection scope of the present application.

Claims

1. A fire suppression system for an energy storage cabinet based on liquid nitrogen extinguishing, wherein the energy storage cabinet contains multiple battery packs, characterized in that, This includes control devices, fire extinguishing devices, and nitrogen circulation devices installed in the energy storage cabinet; The control device includes a liquid nitrogen controller and detectors. The detectors include multiple in-pack detectors and one in-cabinet detector. The multiple in-pack detectors are respectively installed in multiple battery packs, and the in-cabinet detector is installed in the energy storage cabinet. The detectors are used to detect the temperature, CO concentration, smoke concentration, and combustible gas concentration of the space in which they are located. All detectors are connected to the liquid nitrogen controller to upload the collected parameter information of temperature, CO concentration, smoke concentration, and combustible gas concentration. The fire extinguishing device includes a liquid nitrogen storage and conversion tank and a spraying device. The liquid nitrogen storage and conversion tank is connected to the spraying device through an output pipeline. The spraying device includes multiple in-pack liquid nitrogen nozzles and one in-cabinet liquid nitrogen nozzle. The in-pack liquid nitrogen nozzles are respectively installed in the battery pack, and the in-cabinet liquid nitrogen nozzle is installed in the energy storage cabinet. The detector inside the pack is connected to and controls the liquid nitrogen nozzle inside the corresponding battery pack, and the detector inside the cabinet is connected to and controls the liquid nitrogen nozzle inside the energy storage cabinet. The liquid nitrogen storage and conversion tank includes a liquid nitrogen storage tank and a nitrogen gas storage tank, which are connected together. The liquid nitrogen stored in the liquid nitrogen storage tank and the nitrogen gas stored in the nitrogen gas storage tank can be converted into each other. Both the liquid nitrogen storage tank and the nitrogen gas storage tank are connected to the output pipeline. The nitrogen circulation device includes nitrogen circulation connectors disposed in multiple battery packs. The nitrogen circulation connectors are connected to the nitrogen storage tanks through circulation pipelines. The nitrogen storage tanks, the output pipelines, the liquid nitrogen nozzles inside the packs, the battery packs, the nitrogen circulation connectors, and the circulation pipelines constitute a nitrogen circulation loop. The liquid nitrogen controller controls the operation of the injection device based on the parameter information collected by the detector.

2. The energy storage cabinet fire suppression system based on liquid nitrogen extinguishing as described in claim 1, characterized in that, The liquid nitrogen nozzle inside the pack is located on one side of the battery pack, the nitrogen circulation connector is located on the other side of the battery pack, and the detector inside the pack is installed on the front panel of the battery pack.

3. The energy storage cabinet fire suppression system based on liquid nitrogen extinguishing as described in claim 1, characterized in that, The detector inside the cabinet is located at the top of the energy storage cabinet, and the liquid nitrogen nozzle inside the cabinet is located in the upper part of the energy storage cabinet and above the battery pack.

4. The energy storage cabinet fire protection system based on liquid nitrogen extinguishing as described in claim 1, characterized in that, It also includes an audible and visual alarm, which is connected to and controlled by the liquid nitrogen controller.

5. The energy storage cabinet fire protection system based on liquid nitrogen extinguishing as described in claim 1, characterized in that, The liquid nitrogen controller communicates with the detector via a CAN bus or RS485 bus, and the liquid nitrogen controller also communicates with the fire control center.

6. A control method for a fire suppression system for an energy storage cabinet based on liquid nitrogen extinguishing as described in any one of claims 1-5, characterized in that, Includes the following steps: The liquid nitrogen controller acquires parameter information such as temperature, CO concentration, smoke concentration, and combustible gas concentration collected by the detector; When the values ​​of all parameters collected by the detectors are lower than the first warning value, the energy storage cabinet is in normal working condition, and the detector inside the pack controls the liquid nitrogen nozzle inside the corresponding battery pack to spray nitrogen into the battery pack at a first frequency to assist in heat dissipation. When the value of any parameter collected by any detector is higher than the first warning value but lower than the second warning value, the liquid nitrogen controller will activate the audible and visual alarm and issue a first-level warning signal. If the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray nitrogen into the battery pack at the second frequency; if the detector is an in-cabinet detector, it controls the in-cabinet liquid nitrogen nozzle to spray nitrogen into the cabinet at the second frequency. When the value of any parameter collected by any detector is higher than the second warning value but lower than the third warning value, the liquid nitrogen controller will activate the audible and visual alarm and issue a second-level warning signal. If the detector is an in-pack detector, it controls the liquid nitrogen nozzle in the corresponding battery pack to spray nitrogen into the battery pack at the third frequency; if the detector is an in-cabinet detector, it controls the liquid nitrogen nozzle in the cabinet to spray nitrogen into the cabinet at the third frequency. When the value of any parameter collected by any detector is higher than the third warning value, the liquid nitrogen controller will activate the audible and visual alarm and issue a level three warning signal. If the detector is an in-pack detector, it controls the liquid nitrogen nozzle in the corresponding battery pack to spray liquid nitrogen into the battery pack at the fourth frequency; if the detector is an in-cabinet detector, it controls the liquid nitrogen nozzle in the cabinet to continuously spray liquid nitrogen into the cabinet until the values ​​of all parameters collected by the detector are lower than the third warning value.

7. The control method for the energy storage cabinet fire protection system based on liquid nitrogen extinguishing as described in claim 6, characterized in that, When the liquid nitrogen controller issues a level 3 warning signal and the spraying device sprays liquid nitrogen, if the values ​​of all parameters collected by the detector are lower than the third warning value, the following steps are also included: if the detector is an in-pack detector, the in-pack detector controls the in-pack liquid nitrogen nozzle in the corresponding battery pack to spray liquid nitrogen into the battery pack at the fifth frequency within a set time; if the detector is an in-cabinet detector, it controls the in-cabinet liquid nitrogen nozzle to spray liquid nitrogen into the cabinet at the fifth frequency within a set time.

8. The control method for the energy storage cabinet fire protection system based on liquid nitrogen extinguishing as described in claim 7, characterized in that, The first warning value, the second warning value, and the third warning value increase sequentially, the first frequency, the second frequency, and the third frequency increase sequentially, and the fourth frequency is greater than the fifth frequency.

9. The control method for the energy storage cabinet fire protection system based on liquid nitrogen extinguishing as described in claim 6, characterized in that, When the liquid nitrogen storage tank of the liquid nitrogen storage conversion tank is injected with nitrogen by the injection device, and the pressure inside the nitrogen storage tank is lower than the set value, the stored liquid nitrogen is transferred to the nitrogen storage tank and converted into nitrogen gas; when the liquid nitrogen storage tank is injected with liquid nitrogen by the injection device, and the pressure inside the liquid nitrogen storage tank is lower than the set value, the stored nitrogen gas is transferred to the liquid nitrogen storage tank and converted into liquid nitrogen.

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