Gravity-assisted immersion water fire extinguishing system for battery swap cabinet and control method

Abstract

The application discloses a gravity-assisted submerged water fire extinguishing system for battery replacement cabinet and a control method, and belongs to the technical field of fire safety of battery replacement cabinet, which comprises a battery replacement cabinet, a water storage tank, a battery compartment, a fire-fighting pipeline and an internal module, the water storage tank is installed on the top of the battery replacement cabinet and is higher than the battery compartment, a water outlet at the bottom is sequentially connected with a liquid level sensor one, a flow sensor and a water pump through the fire-fighting pipeline, the battery compartment is provided with a fire-fighting nozzle, a temperature sensor and a liquid level sensor two, and the top is provided with a water overflow outlet and / or a steam outlet, the internal module comprises a fire-fighting control panel and a central control panel, the fire-fighting control panel is electrically connected with each sensor and water pump and communicates with the central control panel, and the system control method comprises the steps of system initialization, nozzle self-explosion, signal detection, fire determination, pressure boosting water injection and water level control. The application adopts a water supply mode combining gravity self-flow and water pump pressure boosting, realizes rapid submerged fire extinguishing when the battery is out of control, reduces the false alarm rate and improves the fire-fighting reliability of the battery replacement cabinet.

Description

Technical Field

[0001] This invention relates to the field of fire safety technology for battery swapping cabinets, specifically to a gravity-assisted immersion water fire protection system and control method for battery swapping cabinets. Background Technology

[0002] As battery swapping cabinets become increasingly common in cities, the industry has placed higher demands on their fire safety to meet the deployment requirements of areas with high fire safety standards, such as residential areas and basements. Currently, common fire-fighting methods for battery swapping cabinets include aerosol sprays, dry powder extinguishers, carbon dioxide extinguishers, and water sprinkler systems. However, the unique characteristic of lithium battery thermal runaway is that its positive electrode material can decompose and release oxygen at high temperatures, thus the thermal runaway process does not require external oxygen.

[0003] Traditional fire extinguishing methods (such as dry powder, carbon dioxide, and aerosol) mainly extinguish open flames by isolating oxygen or inhibiting gaseous free radicals. They cannot effectively block the exothermic chemical reactions inside lithium batteries, and can only suppress the flames temporarily, making reignition highly likely. Practice has shown that only by completely immersing the lithium battery in water, using water's high specific heat capacity to rapidly cool it down, and simultaneously isolating it from oxygen, can the fire be completely extinguished and the thermal runaway reaction stopped.

[0004] Therefore, submersible water fire suppression is widely recognized as the most effective fire extinguishing solution for power swapping cabinets. However, existing submersible water fire suppression designs have the following fatal flaws: High cost hinders large-scale deployment: Existing solutions typically rely on complex electric valves, high-pressure water pumps, precision flow control systems, and customized water circulation devices, resulting in fire protection costs of 300-500 yuan per compartment, accounting for more than 30% of the total cost of the battery swapping cabinet. For battery swapping cabinet operators requiring large-scale deployment, such costs are unbearable, severely hindering the promotion of immersion fire protection technology within the industry.

[0005] High dependence on reliable backup power: Existing submersible water fire suppression systems rely entirely on electrically driven pumps and valves. If external power is interrupted (e.g., due to a fire causing a power grid trip or mains power failure), and if a backup power source fails or is not configured, the system will be completely paralyzed and unable to fill with water for firefighting. In actual deployment environments, mains power failures or damaged wiring are not uncommon, posing a serious safety hazard. Even more serious is that if the external power supply is interrupted and the backup battery in the cabinet also fails to supply power due to aging, undervoltage, or its own failure (i.e., the backup power supply is completely ineffective), the existing system will be completely paralyzed and lose all fire-fighting capabilities. This extreme situation may occur in the deployment environment of the battery swapping cabinet when it is unattended.

[0006] To address the aforementioned issues, there is an urgent need in this field for a low-cost, low-power, safety-redundant, and externally independent immersion water fire suppression solution. Summary of the Invention

[0007] To achieve the above objectives, the present invention provides the following technical solution: A gravity-assisted submersible water fire suppression system for a battery swapping cabinet includes: a battery swapping cabinet, a water storage tank, a battery compartment, fire-fighting piping, and an internal module. The water storage tank is installed on top of the battery swapping cabinet, above the battery compartment, and is used to store fire-fighting water. An outlet is installed at the bottom of the water storage tank, and the outlet is connected sequentially to a level sensor, a flow sensor, and a water pump via the fire-fighting piping. The flow sensor detects water flow signals within the fire-fighting piping and sends a trigger signal to the internal module when water flow is detected. Multiple battery compartments are included, and each battery compartment contains a fire sprinkler head, a temperature sensor, and a level sensor, and has an overflow outlet and / or... The steam outlet and overflow outlet are located above the maximum water level required for battery immersion, used to drain excess water in case of overfilling; the steam outlet is used to discharge water vapor generated by battery thermal runaway; a sprinkler head protection plate is installed around the fire sprinkler head to prevent accidental contact and protect the sprinkler head from mechanical damage or blockage by foreign objects, and the fire sprinkler head is connected to the water outlet. The fire sprinkler head is a heat-sensitive self-exploding sprinkler head, and its self-explosion temperature is set to the critical temperature of battery thermal runaway in the battery compartment. When the temperature in the battery compartment reaches this critical temperature, the fire sprinkler head automatically explodes and opens, and water in the water storage tank is injected into the battery compartment through the fire pipe under the action of gravity.

[0008] Furthermore, the internal module includes a fire control board and a central control board, wherein the fire control board is electrically connected to the temperature sensor, liquid level sensor one, liquid level sensor two, flow sensor, and water pump, and the fire control board is communicatively connected to the central control board.

[0009] Furthermore, a depth sensor is also provided at the bottom of the water storage tank to detect the remaining water level in the tank; the fire control panel monitors the remaining water level in the water storage tank based on the signal from the depth sensor, and issues an alarm when the water level is insufficient.

[0010] Furthermore, the power supply for the fire control panel consists of two paths: one path is powered by external AC power via a power conversion module, and the other path is powered by any normal battery in the battery swapping cabinet via DC power. DC step-down reverse power supply forms a backup power supply; when the external AC power is cut off, it automatically switches to the backup power supply. The pre-set program of the fire control board is as follows: after receiving the trigger signal from the flow sensor, it determines whether a fire has occurred by combining the signal from the temperature sensor. If a fire is confirmed, the water pump is started to increase the pressure, and the signal from the second liquid level sensor is received. When the liquid level reaches the preset height to submerge the battery, the water pump is controlled to stop or work intermittently.

[0011] Furthermore, the fire control board communicates with the central control board via a CAN bus; the fire control board is also configured to: when a fire is detected, send a fire alarm signal to the central control board, which then uploads it to the backend server and activates the alarm; and simultaneously actively cut off the external AC power supply and switch to the backup power supply mode.

[0012] Furthermore, the fire-fighting pipeline includes a main pipeline and several branch pipelines. The main pipeline is connected to the outlet of the water storage tank, and the branch pipelines are respectively connected to each battery compartment. The main pipeline and the branch pipelines are connected to form a water pipeline.

[0013] Furthermore, the second liquid level sensor is connected to the battery compartment via a flexible hose, forming a water pressure measuring pipeline.

[0014] Preferably, the water pipe and the pressure measuring pipe are arranged vertically, and can be adjusted as needed during actual production.

[0015] On the other hand, the present invention also provides a gravity-assisted immersion water fire-fighting control method for a battery swapping cabinet based on the above system, comprising the following steps: S1: System initialization, the fire control board self-checks the status of each sensor, and enters the standby state after confirming that there are no errors. S2: When the temperature inside any battery compartment reaches the self-explosion temperature of the fire sprinkler head, the fire sprinkler head in that battery compartment will automatically burst and open, and the water in the water tank will flow into the battery compartment through the fire pipe under the action of gravity. S3: The flow sensor sends the water flow signal to the fire control panel after detecting the water flow signal; S4: The fire control board reads the temperature sensor signal of the battery compartment. If the temperature reaches the fire detection threshold or the temperature sensor fails and there is no signal, it is determined to be a fire and proceeds to step S5; otherwise, it is determined to be a false alarm and the process ends. S5: The fire control panel starts the water pump to increase pressure and accelerate the injection of water into the battery compartment; S6: Liquid level sensor 2 detects the water level in the battery compartment in real time. When the water level reaches the preset height to submerge the battery, the fire control panel controls the water pump to stop working. S7: During the fire extinguishing process, when the water level drops below the preset height due to evaporation or vaporization, the fire control panel will restart the water pump to replenish water until the water is submerged again; S8: When the water level in the water storage tank is lower than the preset value, the fire control panel will issue a water shortage alarm.

[0016] Furthermore, in step S5, the fire control board also performs the following operations: sends a fire alarm signal to the central control board, which then uploads it to the backend server and pushes the fire alarm information to relevant personnel; at the same time, it actively cuts off the external AC power supply and switches to the backup power mode where the normal battery in the battery swapping cabinet provides reverse power.

[0017] Further explanation is needed regarding redundancy protection under extreme conditions: When external AC power is interrupted and the backup battery in the battery swapping cabinet also fails to provide power (i.e., the fire control panel and water pump are completely de-energized), the system automatically enters a "pure gravity passive fire suppression mode." In this mode, the burst fire sprinklers remain open, and the water in the storage tank continuously flows into the burning battery compartment through the fire suppression pipes, relying solely on gravitational potential energy. Due to the lack of a water pump for pressurization, the water flow rate is relatively small, and the time required to completely submerge the battery is longer compared to when pressurization is in place (depending on the installation height of the storage tank and the pipe resistance). However, as long as the storage tank capacity and installation height are properly designed, gravity flow can eventually fill the battery compartment to the overflow height, achieving complete submersion and extinguishing or effective cooling of the burning battery. Technicians can determine the minimum installation height and minimum volume of the storage tank required for pure gravity fire suppression through simple calculations or experiments. This mode ensures that even under the most unfavorable conditions of complete power outage, the system can still provide a basic and effective fire response, greatly improving the safety and reliability of the battery swapping cabinet.

[0018] Furthermore, in step S7, if the level sensor 2 fails during the fire extinguishing process, the fire control panel controls the water pump to continue working until all the water in the water storage tank is injected into the battery compartment, and the excess water is discharged from the overflow outlet.

[0019] In another embodiment of the present invention, The present invention also provides a battery swapping cabinet, which is equipped with the gravity-assisted immersion water fire protection system described in any of the above claims.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention uses a combination of gravity-assisted water supply and water pump pressurization. Initial gravity water supply is achieved by installing the water tank at a high position, and rapid water injection is achieved by combining it with water pump pressurization. This can quickly immerse the thermal runaway battery, achieve continuous cooling, and effectively prevent reignition. 2. It adopts a dual triggering logic of thermal self-exploding nozzles, flow sensors, and temperature sensors, which can accurately identify fires, reduce false alarm rates, and achieve precise fire suppression for individual battery compartments, avoiding water waste; 3. A dual power supply system is set up, which combines external AC power with reverse power supply from the normal batteries in the battery swapping cabinet. When the external power fails, it can automatically switch to the backup power supply to ensure the continuous operation of the fire protection system. 4. Closed-loop control of water level and volume is achieved through liquid level sensors and depth sensors. Combined with overflow outlet and steam outlet, it can ensure that the battery is completely submerged and discharge excess water and steam, thereby improving the safety and reliability of fire extinguishing. 5. Linked with the central control board of the battery swapping cabinet, it enables the uploading and push of fire alarm signals, facilitating real-time monitoring and emergency response in the background, and improving the overall fire safety level of the battery swapping cabinet.

[0021] 6. This invention possesses passive emergency firefighting capabilities, achieving ultimate safety redundancy: even if the external AC power supply is interrupted and the backup battery completely fails (i.e., the entire system is powered down), this invention can still function normally. When the heat-sensitive self-destructing sprinkler head is activated at fire temperatures, the water tank, due to the gravitational potential energy generated by its elevated installation, can continuously fill the battery compartment with water until the battery is submerged. Although there is no water pump to pressurize the system, and the water filling time will be correspondingly extended, gravity flow can still provide sufficient fire-extinguishing water to completely extinguish the fire or effectively inhibit the spread of thermal runaway. This characteristic enables the system to maintain basic and reliable firefighting capabilities even under extreme conditions of complete power failure, breaking through the absolute dependence of existing technologies on electricity. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the battery swapping cabinet of the present invention; Figure 2 This is a schematic diagram of the internal layout of the water storage tank of the present invention; Figure 3 This is a schematic diagram of the battery compartment structure of the present invention (I); Figure 4 This is a schematic diagram (II) of the battery compartment structure of the present invention; Figure 5 This is a schematic cross-sectional view of the internal structure of the battery compartment of the present invention; Figure 6 This is a flowchart illustrating the connection relationships between the various hardware modules of this invention; Figure 7 This is a control flowchart of the water fire protection system of the present invention; The diagram shows the following components: 1. Battery swapping cabinet; 2. Water storage tank; 2.1. Level sensor 1; 2.2. Flow sensor; 2.3. Water pump; 2.4. Outlet; 2.5. Depth sensor; 3. Compartment door; 4. Battery compartment; 4.1. Fire sprinkler head; 4.1.1. Sprinkler head protection plate; 4.2. Temperature sensor; 4.3. Level sensor 2; 4.4. Hoses; 4.5. Overflow outlet; 5. Battery; 6. Fire protection piping; 6.1. Main piping; 6.2. Branch piping; 8. Internal module; 8.1. Fire control board; 8.2. Central control board; 9. Water piping; 10. Water pressure measuring piping; 11. Backend server. 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, not all, of the embodiments of the present invention. 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] It should be understood that the terms “system,” “device,” “unit,” and / or “module” used herein are one way to distinguish different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0025] To better understand the overall technical solution of the submersible water fire-fighting system according to the embodiments of the present invention, the following detailed description of each embodiment of the submersible water fire-fighting system provided by the present invention is provided in conjunction with the accompanying drawings.

[0026] Example 1, as Figure 1-6As shown, a gravity-assisted submersible water fire suppression system for a battery swapping cabinet according to this embodiment includes: a battery swapping cabinet 1, a water storage tank 2, a battery compartment 4, a fire-fighting pipeline 6, and an internal module 8. The water storage tank 2 is installed on top of the battery swapping cabinet 1, above the battery compartment, and is used to store fire-fighting water. An outlet 2.4 is installed at the bottom of the water storage tank 2, and the outlet 2.4 is connected in sequence to a level sensor 2.1, a flow sensor 2.2, and a water pump 2.3 via the fire-fighting pipeline 6. The flow sensor 2.2 is used to detect the water flow signal in the fire-fighting pipeline 6, and sends a trigger signal to the internal module 8 when water flow is detected. There are multiple battery compartments 4, and each battery compartment 4 is equipped with a fire sprinkler head 4.1 and a temperature sensor. 4.2 and level sensor 4.3 are provided with an overflow port 4.5 and / or a steam outlet on the top. The overflow port 4.5 is located above the highest water level required to submerge the battery 5, and is used to discharge excess water when there is excessive water injection. The steam outlet is used to discharge water vapor generated by battery thermal runaway. The fire sprinkler head 4.1 is surrounded by a sprinkler head protection plate 4.1.1, and the fire sprinkler head 4.1 is connected to the water outlet 2.4. The fire sprinkler head 4.1 is a heat-sensitive self-exploding sprinkler head, and its self-explosion temperature is set to the critical temperature of battery thermal runaway in the battery compartment. When the temperature in the battery compartment 4 reaches the critical temperature, the fire sprinkler head 4.1 automatically explodes and opens, and the water in the water storage tank 2 is injected into the battery compartment 4 through the fire pipe under the action of gravity.

[0027] It should be noted that the internal structure of the battery swapping cabinet, including the specific structural design of compartment door 3, can be referenced from existing technologies and will not be elaborated here.

[0028] It should be further noted that the internal module 8 includes a fire control board 8.1 and a central control board 8.2. The fire control board 8.1 is electrically connected to the temperature sensor 4.2, the liquid level sensor 1 2.1, the liquid level sensor 2 4.3, the flow sensor 2.2, and the water pump 2.3, and the fire control board 8.1 is communicatively connected to the central control board 8.2.

[0029] It should be further noted that a depth sensor 2.5 is also installed at the bottom of the water storage tank 2 to detect the remaining water volume in the water storage tank 2; the fire control board 8.1 monitors the remaining water volume in the water storage tank 2 based on the signal from the depth sensor 2.5, and issues an alarm when the water volume is insufficient.

[0030] It should be further noted that the power supply for the fire control panel 8.1 consists of two paths: one path is powered by external AC power via a power conversion module, and the other path is powered by any normal battery in the battery swapping cabinet 1 via DC power. DC step-down reverse power supply forms a backup power supply; when the external AC power fails, it automatically switches to the backup power supply. The pre-set program of the fire control board 8.1 is as follows: after receiving the trigger signal from the flow sensor 2.2, it combines the signal from the temperature sensor 4.2 to determine whether a fire has occurred. If a fire is confirmed, it starts the water pump to increase the pressure and receives the signal from the liquid level sensor 4.3. When the liquid level reaches the preset height to submerge the battery, it controls the water pump to stop or work intermittently.

[0031] It should be further noted that the fire control board 8.1 communicates with the central control board 8.2 via a CAN bus; the fire control board 8.1 is also configured to: when a fire is detected, send a fire alarm signal to the central control board 8.2, which will then upload the signal to the backend server and activate the alarm; at the same time, actively cut off the external AC power supply and switch to the backup power supply mode.

[0032] It should be further explained that the fire-fighting pipeline 6 includes a main pipeline 6.1 and several branch pipelines 6.2. The main pipeline 6.1 is connected to the outlet 2.4 of the water storage tank 2, and the branch pipelines 6.2 are respectively connected to each battery compartment 4. The main pipeline 6.1 and the branch pipelines 6.2 are connected to form a water pipeline 9, and the main pipeline 6.1 and several branch pipelines 6.2 are connected by a T-joint to achieve independent water supply. Furthermore, the level sensor 4.3 is connected to the battery compartment 4 via a hose 4.4, forming a water pressure measuring pipe 10.

[0033] Preferably, the water pipe 9 and the pressure measuring pipe 10 are arranged vertically, and can be adjusted as needed during actual production.

[0034] Example 2, according to some embodiments of this application, such as Figure 7 As shown, a gravity-assisted immersion water fire-fighting control method for a battery swapping cabinet based on the above system is also provided, including the following steps: S1: System initialization, the fire control board 8.1 self-checks the status of each sensor, and enters the standby state after confirming that there are no errors; S2: When the temperature inside any battery compartment 4 reaches the self-explosion temperature of the fire sprinkler head 4.1, the fire sprinkler head 4.1 of the battery compartment 4 will automatically burst and open, and the water in the water storage tank 2 will flow into the battery compartment 4 through the fire pipe 6 under the action of gravity. S3: After the flow sensor 2.2 detects the water flow signal, it sends it to the fire control board 8.1; S4: The fire control board 8.1 reads the signal from the temperature sensor 4.2 of the battery compartment 4. If the temperature reaches the fire detection threshold or the temperature sensor 4.2 fails and has no signal, it is determined to be a fire and proceeds to step S5; otherwise, it is determined to be a false alarm and the process ends. S5: Fire control panel 8.1 starts water pump 2.3 pressurizes and accelerates water injection into battery compartment 4; Furthermore, as a redundancy guarantee under extreme operating conditions, when the external AC power supply is interrupted and the backup battery in the battery swapping cabinet 1 is also unable to supply power (i.e., the fire control panel and water pump are completely de-energized), the system automatically enters the "pure gravity passive fire protection mode". In this mode, the burst fire sprinkler head 4.1 remains open, and the water in the water tank relies solely on gravitational potential energy to continuously inject water into the burning battery compartment through the fire pipe 6. Since there is no water pump pressurization, the water injection flow rate is small, and the time required to completely submerge the battery will be longer than when there is pressurization (the specific time depends on the installation height of the water tank and the pipe resistance). However, as long as the capacity and installation height of the water tank 2 are designed reasonably, gravity flow can eventually fill the battery compartment to the overflow height, achieving complete immersion extinguishing or effective cooling of the burning battery. Technicians can determine the minimum installation height and minimum volume of the water tank required to meet pure gravity fire extinguishing through simple calculations or experiments. This mode ensures that even under the most unfavorable conditions of complete power failure, the system can still provide a basic and effective fire response, greatly improving the safety and reliability of the battery swapping cabinet.

[0035] S6: Liquid level sensor 24.3 detects the water level in the battery compartment in real time. When the water level reaches the preset height to submerge the battery, the fire control board 8.1 controls the water pump 2.3 to stop working. S7: During the fire extinguishing process, when the water level drops below the preset height due to evaporation or vaporization, the fire control panel 8.1 will restart the water pump to replenish water until the water is submerged again; S8: When the water level in water tank 2 is lower than the preset value, the fire control panel 8.1 will issue a water shortage alarm.

[0036] It should be further noted that in step S5, the fire control board 8.1 also performs the following operations: sends a fire alarm signal to the central control board 8.2, which is then uploaded to the backend server 11 and the fire alarm information is pushed to relevant personnel; at the same time, it actively cuts off the external AC power supply and switches to the backup power mode of reverse power supply from the normal battery in the battery swapping cabinet 1.

[0037] It should be further noted that in step S7, if the liquid level sensor 4.3 fails during the fire extinguishing process, the fire control board 8.1 controls the water pump 2.3 to continue working until all the water in the water storage tank 2 is injected into the battery compartment 4, and the excess water is discharged from the overflow outlet.

[0038] The present invention also provides a battery swapping cabinet, which is equipped with any of the above-mentioned gravity-assisted immersion water fire protection systems.

[0039] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A gravity-assisted immersion water fire suppression system for a battery swapping cabinet, characterized in that, include: The system includes a battery swapping cabinet, a water storage tank, battery compartments, fire-fighting piping, and internal modules. The water storage tank, installed on top of the battery swapping cabinet and above the battery compartments, stores fire-fighting water. An outlet is installed at the bottom of the water storage tank, and this outlet is connected sequentially to a level sensor, a flow sensor, and a water pump via a fire-fighting piping. The flow sensor detects water flow signals within the fire-fighting piping and sends a trigger signal to the internal modules when water flow is detected. Multiple battery compartments are included, each containing a fire sprinkler head, a temperature sensor, and a level sensor. An overflow outlet and / or [other outlet] are located at the top of each battery compartment. The steam outlet, with its overflow position higher than the maximum water level required for battery immersion, is used to discharge excess water in case of overfilling. The steam outlet also discharges water vapor generated by battery thermal runaway. A sprinkler head protection plate is installed around the sprinkler head, which is connected to the outlet. The sprinkler head is a heat-sensitive self-exploding type, with its self-explosion temperature set to the critical temperature of battery thermal runaway within the battery compartment. When the temperature inside the battery compartment reaches this critical temperature, the sprinkler head automatically explodes and opens, allowing water from the storage tank to be injected into the battery compartment through the fire-fighting pipe under gravity.

2. The gravity-assisted submersible water fire suppression system for the battery swapping cabinet according to claim 1, characterized in that, The internal module includes a fire control board and a central control board. The fire control board is electrically connected to the temperature sensor, liquid level sensor one, liquid level sensor two, flow sensor, and water pump, and the fire control board is communicatively connected to the central control board.

3. The gravity-assisted immersion water fire suppression system for the battery swapping cabinet according to claim 2, characterized in that, The bottom of the water tank is also equipped with a depth sensor to detect the remaining water level in the tank; The fire control panel monitors the remaining water level in the water tank based on signals from the depth sensor, and issues an alarm when the water level is insufficient.

4. The gravity-assisted immersion water fire suppression system for the battery swapping cabinet according to claim 2, characterized in that, The fire control board is powered by two circuits: one is from external AC power via a power conversion module, and the other is from any normal battery in the battery swapping cabinet via a DC-DC step-down reverse power supply to form a backup power supply. When the external AC power fails, it automatically switches to the backup power supply. The fire control board is pre-programmed as follows: after receiving the trigger signal from the flow sensor, it determines whether a fire has occurred by combining the signal from the temperature sensor. If a fire is confirmed, it starts the water pump to increase pressure and receives the signal from the second liquid level sensor. When the liquid level reaches the preset height to submerge the battery, it controls the water pump to stop or operate intermittently.

5. The gravity-assisted submersible water fire suppression system for the battery swapping cabinet according to claim 2, characterized in that, The fire control board communicates with the central control board via a CAN bus. The fire control board is also configured to: when a fire is detected, send a fire alarm signal to the central control board, which will then upload the signal to the backend server and activate the alarm; and simultaneously, actively cut off the external AC power supply and switch to the backup power supply mode.

6. The gravity-assisted submersible water fire suppression system for the battery swapping cabinet according to claim 1, characterized in that, The fire-fighting pipeline includes a main pipeline and several branch pipelines. The main pipeline is connected to the outlet of the water storage tank, and the branch pipelines are respectively connected to each battery compartment. The main pipeline and the branch pipelines are connected to form a water pipeline.

7. The gravity-assisted submersible water fire suppression system for the battery swapping cabinet according to claim 1, characterized in that, The second liquid level sensor is connected to the battery compartment via a flexible hose, forming a water pressure measuring pipeline.

8. A gravity-assisted submersible water fire-fighting control method for a battery swapping cabinet based on the system described in any one of claims 1-7, characterized in that, Includes the following steps: S1: System initialization, the fire control board self-checks the status of each sensor, and enters the standby state after confirming that there are no errors. S2: When the temperature inside any battery compartment reaches the self-explosion temperature of the fire sprinkler head, the fire sprinkler head in that battery compartment will automatically burst and open, and the water in the water tank will flow into the battery compartment through the fire pipe under the action of gravity. S3: The flow sensor sends the water flow signal to the fire control panel after detecting the water flow signal; S4: The fire control board reads the temperature sensor signal of the battery compartment. If the temperature reaches the fire detection threshold or the temperature sensor fails and there is no signal, it is determined to be a fire and proceeds to step S5; otherwise, it is determined to be a false alarm and the process ends. S5: The fire control panel starts the water pump to increase pressure and accelerate the injection of water into the battery compartment; In step S5, the fire control board also performs the following operations: sends a fire alarm signal to the central control board, which uploads it to the backend server and pushes the fire alarm information to relevant personnel; at the same time, it actively cuts off the external AC power supply and switches to the backup power mode where the normal battery in the battery swapping cabinet provides reverse power. S6: Liquid level sensor 2 detects the water level in the battery compartment in real time. When the water level reaches the preset height to submerge the battery, the fire control panel controls the water pump to stop working. S7: During the fire extinguishing process, when the water level drops below the preset height due to evaporation or vaporization, the fire control panel will restart the water pump to replenish water until the water is submerged again; S8: When the water level in the water storage tank is lower than the preset value, the fire control panel will issue a water shortage alarm.

9. The gravity-assisted immersion water fire-fighting control method for a battery swapping cabinet according to claim 8, characterized in that, In step S7, if the level sensor 2 fails during the fire extinguishing process, the fire control panel controls the water pump to continue working until all the water in the water storage tank is injected into the battery compartment, and the excess water is discharged from the overflow outlet.

10. A battery swapping cabinet, characterized in that, The battery swapping cabinet is equipped with a gravity-assisted submersible water fire-fighting system as described in any one of claims 1-7.

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