Submerged energy storage battery thermal management system and fire control method

Abstract

The application discloses an immersed energy storage battery thermal management system and a fire control method. The immersed energy storage battery thermal management system comprises a battery cabinet, an immersed circulating system and a battery management system. The battery cabinet comprises at least one battery box, and the battery box contains a plurality of battery cells immersed in cooling liquid. The immersed circulating system is connected with the battery box respectively. The battery management system is used for determining whether irreversible thermal runaway occurs in the battery cell and controlling the immersed circulating system to intermittently pump the cooling liquid into the battery box where the battery cell occurs irreversible thermal runaway when the irreversible thermal runaway occurs in the battery cell. In the time interval between each two times of pumping the cooling liquid, the battery cell where the thermal runaway occurs is always covered by the cooling liquid. The application can overcome the problems and defects of high fire extinguishing cost, poor response timeliness, low reliability and complex structure in the existing energy storage battery fire control system.

Description

Technical Field

[0001] This invention relates to a thermal management system and fire control method for an immersion energy storage battery, belonging to the field of energy storage battery technology. Background Technology

[0002] Currently, the core of energy storage systems is the battery system, which typically contains hundreds of cells. When a single cell experiences thermal runaway, the violent reaction can ignite surrounding cells, causing a fire. The fire suppression systems currently used in the energy storage battery industry are typically gaseous fire suppression systems and fine water mist fire suppression systems. Gaseous fire suppression systems can be further divided into systems using heptafluoropropane and perfluorohexanone, among others. Furthermore, the industry has gradually developed fire suppression systems at the battery module level. The cells themselves are still cooled using traditional cold-plate liquid cooling or air cooling. In the event of thermal runaway in a cell, additional fire suppression branches and coolant tanks are used to inject coolant into the battery module to achieve flooding fire suppression.

[0003] First, regarding gaseous fire suppression systems, heptafluoropropane systems can only be used as whole-cabin total flooding systems and cannot directly target battery cells. Their extinguishing efficiency is low, and they lack cooling effects, making reignition easy. Perfluorohexanone systems can achieve battery module-level fire suppression, but require specific nozzles due to the need for good atomization, resulting in a more complex structure. Second, while fine water mist systems offer good cooling performance, their high overall pressure poses a certain risk. Furthermore, they are still whole-cabin total flooding systems; while extinguishing localized fires, they can cause other battery cells to become ineffective, leading to significant overall losses.

[0004] Finally, the flooding fire protection system achieved by injecting liquid into the module has the following disadvantages:

[0005] The water-based coolant injected during thermal runaway is conductive and can easily cause short circuits in other battery cells, thus intensifying the fire.

[0006] Controlling coolant injection via a solenoid valve presents challenges in terms of response time. Furthermore, if the solenoid valve fails, coolant may drip onto other battery cells, potentially causing a short circuit, resulting in low reliability.

[0007] Adding fire-fighting pipes and a liquid storage tank to the existing battery system would complicate the overall structure and increase the footprint. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide an immersion energy storage battery thermal management system, which can overcome the problems and defects of existing energy storage battery fire protection systems, such as high fire extinguishing cost, poor response time, low reliability and complex structure.

[0009] To solve the above-mentioned technical problems, the technical solution of the present invention is: an immersion energy storage battery thermal management system, comprising:

[0010] The battery cabinet includes at least one battery box containing a plurality of battery cells immersed in coolant.

[0011] An immersion circulation system, wherein the immersion circulation system is connected to the battery box;

[0012] A battery management system is used to determine whether a cell has experienced irreversible thermal runaway and, when a cell experiences irreversible thermal runaway, to control an immersion circulation system to intermittently pump coolant into the battery box containing that cell. During the time interval between two coolant pumping operations, the cell experiencing thermal runaway is always covered by coolant.

[0013] Furthermore, the immersion circulation system includes:

[0014] A solenoid valve connected to the coolant inlet of the battery compartment;

[0015] The coolant piping system includes a return line, a supply line, a pump, and a tank. The supply line is connected to each solenoid valve, and each coolant outlet of the battery box is connected to the return line.

[0016] The battery management system controls the pumping of coolant into the corresponding battery compartment by controlling the corresponding solenoid valves.

[0017] The battery management system uses a pump to control the amount of coolant pumped into the corresponding battery compartment.

[0018] Furthermore, the coolant pipeline is also equipped with an external heat exchange device for exchanging heat with the coolant.

[0019] Furthermore, in order to monitor the operating status of the immersion circulation system, a liquid supply pressure sensor is installed on the liquid supply pipeline;

[0020] And / or a return pressure sensor is provided on the return pipeline.

[0021] Furthermore, in order to prevent contaminants generated during thermal runaway of the battery cell from flowing back into the battery box under normal conditions, otherwise the contaminants would make the cooling environment of the battery cell 10 harsh and affect the heat exchange effect, a one-way valve is connected between the coolant outlet of the battery box and the return pipeline.

[0022] Furthermore, an explosion-proof valve is provided at the upper end of the battery box;

[0023] An alarm sensor is installed above the battery cabinet, and the alarm sensor is connected to the battery management system; the alarm sensor is adapted to trigger an alarm to send an alarm signal and transmit the alarm signal to the battery management system.

[0024] The alarm sensor is a smoke detector and / or a combustible gas detector; wherein...

[0025] The smoke alarm is adapted to be triggered by gas ejected from the battery box when the gas pressure inside the battery box accumulates to a certain value, so as to issue an alarm signal.

[0026] The combustible gas detector is adapted to trigger an alarm and issue an alarm signal when the concentration of combustible gas in the battery cabinet reaches a certain value.

[0027] Furthermore, the battery management system is also used to monitor the surface temperature of the battery cells in real time and calculate the rate of change of the surface temperature of the battery cells over time, and determine the working status of the battery box based on the real-time monitoring of the surface temperature of the battery cells, the rate of change of the surface temperature of the battery cells over time, and alarm signals.

[0028] Furthermore, the battery management system issues alarm information based on the cell determination status.

[0029] Furthermore, coolant is intermittently pumped into the battery box containing the cell, and the time interval between each two pumping of coolant is obtained by formula (1);

[0030] in,

[0031] Where L is the rated flow rate of the pump, W is the length of the space above the battery cell, H is the width of the space above the battery cell, and c is the safety factor, which is taken as 1.1 to 1.3.

[0032] The present invention also provides a fire control method, wherein the battery cabinet includes at least one battery box, and the battery box contains a plurality of battery cells immersed in coolant, and the method includes the following steps:

[0033] When an irreversible thermal runaway occurs in a battery cell, coolant is intermittently pumped into the battery box containing that cell. During the time interval between two coolant pumping operations, the cell experiencing thermal runaway is always covered by coolant.

[0034] Furthermore, the criteria for determining irreversible thermal runaway in a battery cell are as follows:

[0035] Battery cabinet smoke alarm or combustible gas alarm, the surface temperature of the battery cell is greater than 60℃, and the temperature change rate of the battery cell surface over time is greater than 1℃ / s.

[0036] Furthermore, the battery cabinet includes multiple battery boxes;

[0037] When an irreversible thermal runaway occurs in a battery cell, locate the cell where the thermal runaway occurred, determine the battery box containing the cell, and stop pumping coolant into other battery boxes.

[0038] Furthermore, the method is implemented based on the aforementioned immersion energy storage battery thermal management system;

[0039] The battery box is equipped with an explosion-proof valve at the top.

[0040] An alarm sensor is installed above the battery cabinet, and the alarm sensor is connected to the battery management system; the alarm sensor is adapted to trigger an alarm to send an alarm signal and transmit the alarm signal to the battery management system.

[0041] The alarm sensor is a smoke detector and / or a combustible gas detector; wherein...

[0042] The smoke alarm is adapted to be triggered by gas ejected from the battery box when the gas pressure inside the battery box accumulates to a certain value, so as to issue an alarm signal.

[0043] The combustible gas detector is adapted to trigger an alarm and issue an alarm signal when the concentration of combustible gas in the battery cabinet reaches a certain value.

[0044] The battery management system is also used to monitor the surface temperature of the battery cells in real time and calculate the rate of change of the surface temperature of the battery cells over time, and determine the working status of the battery box based on the real-time monitoring of the surface temperature of the battery cells, the rate of change of the surface temperature of the battery cells over time, and alarm signals.

[0045] When the battery management system does not receive an alarm signal and the surface temperature of the cell and the rate of change of the cell surface temperature over time are not abnormal, the submerged energy storage battery thermal management system remains in normal operation: at this time, all solenoid valves are open and the pump operates according to the rated operating conditions.

[0046] When the battery management system receives an alarm signal and there are no abnormalities in the surface temperature of the battery cell and the rate of change of the surface temperature of the battery cell over time, the battery management system will issue an alarm signal to remind relevant personnel to go to the site to check the situation. The solenoid valve will remain fully open and the pump will continue to operate under rated conditions.

[0047] When the battery management system does not receive an alarm signal but detects an abnormal surface temperature of the battery cell or an abnormal rate of change of the surface temperature of the battery cell over time, it determines that the battery cell is in the early stage of thermal runaway. The battery management system 12 issues an alarm signal, while the solenoid valve remains fully open and the pump frequency is adjusted to increase the flow rate and accelerate the heat exchange and cooling of the battery cell inside the battery box. When the battery management system detects that the surface temperature of the battery cell and the rate of change of the surface temperature over time have returned to normal, the alarm signal is canceled and the pump frequency is adjusted to the rated operating condition.

[0048] By adopting the above technical solution, the present invention has the following beneficial effects:

[0049] 1) Compared with the use of submerged cooling as a means of fire fighting after thermal runaway of battery cells, the submerged energy storage battery thermal management system described in this invention uses fluorinated liquid with strong insulation and heat exchange performance as coolant, which can simultaneously serve the purposes of cooling and fire fighting. When thermal runaway of battery cells occurs, the latent heat of vaporization of fluorinated liquid when boiling can quickly remove a large amount of heat. It is an active and real-time fire fighting system. Therefore, the fire extinguishing response is timely and there is no need to add additional pipelines as fire fighting pipelines. The structure is simple.

[0050] 2) In the event of thermal runaway, the fire control method of the present invention only needs to jog the pump in the submerged energy storage battery thermal management system to ensure that the thermal runaway cell is always covered with coolant by using the coolant stored in the system itself. No additional storage tank is required. Furthermore, the linkage action after thermal runaway will not cause short circuit risk to other cells. Therefore, the fire extinguishing cost can be effectively reduced and the reliability of the system can be improved.

[0051] 3) By combining the smoke alarm signal or combustible gas alarm signal received by the battery management system with the cell surface temperature and temperature change rate, it can determine whether the cell is thermally runaway and take further action. At the same time, by monitoring the pressure of the liquid entering and leaving the battery box in real time, it provides multiple criteria for judging system abnormalities, improves the overall reliability of the system, and avoids unnecessary losses caused by accidental operation. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of the immersion energy storage battery thermal management system of the present invention;

[0053] Figure 2 This is a schematic diagram of the internal structural dimensions of the battery box. Detailed Implementation

[0054] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0055] like Figures 1-2As shown, a thermal management system for an immersion energy storage battery includes:

[0056] Battery cabinet 11, which includes multiple battery boxes 9, each containing multiple battery cells 10 immersed in coolant 6;

[0057] The submersible circulation system is connected to the battery box 9.

[0058] The battery management system 12 is used to determine whether the cell 10 has experienced irreversible thermal runaway and, when a cell 10 experiences irreversible thermal runaway, to control the immersion circulation system to intermittently pump coolant 6 into the battery box 9 where the cell 10 is located. During the time interval between two pumping of coolant 6, the cell 10 experiencing thermal runaway is always covered by coolant 6.

[0059] In this embodiment, there are multiple battery boxes 9, but there can also be only one battery box 9.

[0060] In this embodiment, as Figure 1 As shown, the submersible circulation system can have the following structure: including:

[0061] Solenoid valves V1 to VN are connected to the coolant inlet of the corresponding battery box 9;

[0062] The coolant piping includes a return line 8, a supply line 7, a pump 1, and a tank 5. The supply line 7 is connected to each solenoid valve, and each coolant outlet of the battery box 9 is connected to the return line 8.

[0063] The battery management system 12 controls the corresponding solenoid valves to control the pumping of coolant 6 into the corresponding battery box 9;

[0064] The battery management system 12 controls the amount of coolant pumped into the corresponding battery compartment 9 via pump 1.

[0065] In this embodiment, pump 1 can be a magnetic pump, and tank 6 can be a pressure stabilizing tank.

[0066] Specifically, coolant 6 enters the battery cabinet 11 through the supply pipe 7, completely submerging the battery cell 10 and carrying away the heat generated by the battery cell 10 during operation. It then enters the pump 1 through the return pipe 8, and the pump 1 delivers the coolant 6 to the external heat exchange equipment 2 for heat dissipation. The coolant then returns to the battery cabinet 11 through the supply pipe 7, thus forming an immersion circulation system.

[0067] The coolant 6 used in the submerged circulation system can be a fluorinated liquid.

[0068] like Figure 1As shown, the coolant pipeline is also equipped with an external heat exchange device 2 for exchanging heat with the coolant.

[0069] like Figure 1 As shown, a liquid supply pressure sensor 3 is installed on the liquid supply line 7, and a liquid return pressure sensor 4 is installed on the liquid return line 8, in order to monitor the operating status of the submersible circulation system.

[0070] In this embodiment, as Figure 1 As shown, each battery box 9 is equipped with explosion-proof valves K1 to KN at the top, solenoid valves V1 to VN at the coolant inlet, and one-way valves Z1 to ZN at the coolant outlet. Taking battery box #1 9 as an example: an explosion-proof valve K1 is installed at the top, a solenoid valve V1 is installed at the coolant inlet, and a one-way valve Z1 is installed at the coolant outlet, and so on. The explosion-proof valves also prevent the outer shell of the battery box 9 from rupturing due to excessive internal pressure. The one-way valves prevent contaminants generated during thermal runaway of the battery cells from flowing back into the battery box under normal conditions; otherwise, the contaminants would degrade the cooling environment of the battery cells 10, affecting the heat exchange effect.

[0071] In this embodiment, the battery box 9 is a sealed structure.

[0072] An alarm sensor is installed above the battery cabinet 11, and the alarm sensor is connected to the battery management system 12; the alarm sensor is adapted to trigger an alarm to send an alarm signal and transmit the alarm signal to the battery management system 12;

[0073] In this embodiment, the alarm sensor may include a smoke detector T1 and a combustible gas detector T2; wherein,

[0074] The smoke detector is designed to be triggered by gas ejected from the battery box 9 when the gas pressure inside the battery box 9 accumulates to a certain value, thereby emitting an alarm signal.

[0075] The combustible gas detector is designed to trigger an alarm and send an alarm signal when the concentration of combustible gas in the battery cabinet 11 reaches a certain value.

[0076] The battery management system 12 is also used to monitor the surface temperature of the battery cell 10 in real time and calculate the rate of change of the surface temperature of the battery cell 10 over time. Based on the real-time monitoring of the surface temperature of the battery cell 10, the rate of change of the surface temperature of the battery cell 10 over time, and the smoke trigger signal and combustible gas trigger signal, the battery box working status is determined.

[0077] The battery management system 12 can also issue alarm information based on the cell determination status.

[0078] The battery management system 12 integrates a cell temperature acquisition unit. The battery management system 12 records the numerical values ​​based on the position coordinates of the cell 10 in the battery box 9. For example, if the temperature T(1,j,t) = 20℃, it means that the surface temperature of the j-th cell in the 1# battery box at time t is 20℃.

[0079] The fire control method of the present invention involves the following process:

[0080] S1: The battery management system 12 monitors the surface temperature of the battery cell 10 in real time and calculates the rate of change of the surface temperature of the battery cell 10 over time. The smoke sensor T1 monitors whether there is smoke in the battery cabinet 11 in real time. When the smoke reaches a certain concentration, a smoke alarm signal is issued. The combustible gas detector T2 monitors the combustible gas concentration in the battery cabinet 11 in real time. When the combustible gas reaches a certain concentration, a combustible gas alarm signal is issued and transmitted to the battery management system 12.

[0081] S2: If the battery management system 12 does not receive smoke alarm signals or combustible gas alarm signals and the cell temperature and temperature change rate are normal (i.e., the cell surface temperature is between 15℃ and 35℃, and the cell surface temperature changes less than 1℃ / s over time), the system will maintain normal operation. At this time, all solenoid valves V1 to VN in the system will be open, and pump 1 will operate under rated conditions.

[0082] S3: If the battery management system 12 receives a smoke alarm signal, but the cell surface temperature is between 15℃ and 35℃, and the rate of change of the cell surface temperature over time is less than 1℃ / s, it can be considered that the smoke sensor T1 has malfunctioned due to the battery cabinet being a non-sealed structure and smoke generated from the outside. At this time, the battery management system 12 sends an alarm signal to the background to remind relevant personnel to go to the site to check the situation. The solenoid valves V1 to VN in the system remain fully open, and pump 1 continues to operate under rated conditions.

[0083] S4: If the battery management system 12 does not receive smoke alarm signals or combustible gas alarm signals, but detects that the surface temperature of the battery cell is greater than 60°C or the rate of change of the battery cell surface temperature over time is greater than 1°C / s, and further detects that the values ​​of the supply pressure sensor 3 and return pressure sensor 4 show a significant upward trend, it is determined that the battery cell is in the early stage of thermal runaway. The battery management system 12 sends an alarm signal to the background, and at the same time adjusts the frequency of pump 1 to increase the system flow rate, accelerate the heat exchange and cooling of the battery cells inside the battery box, and prevent further thermal runaway of the battery cells. At this time, the solenoid valves V1 to VN in the system remain fully open. When the battery management system 12 detects that the surface temperature of the battery cell and the rate of change of the surface temperature over time have returned to normal, it cancels the alarm signal and adjusts the frequency of pump 1 to the rated operating condition.

[0084] S5: If the battery management system 12 receives a smoke alarm signal or a combustible gas alarm signal, and simultaneously monitors that the surface temperature of the battery cell is greater than 60°C and the rate of change of the battery cell surface temperature over time is greater than 1°C / s, and further detects a sharp increase in the values ​​of the supply pressure sensor 3 and the return pressure sensor 4, it is determined that an irreversible thermal runaway of the battery cell has occurred, and the following further steps are taken:

[0085] a) The battery management system 12 locates the specific location of the cell that has experienced thermal runaway and shuts down the DC power supply of the battery cabinet 11, while simultaneously sending an audible and visual alarm to the backend.

[0086] b) The battery management system 12 closes the solenoid valves of the battery boxes corresponding to other cells that have not thermally run away, and only opens the solenoid valves of the battery boxes corresponding to the cells that have thermally run away. For example, if it is determined that the j-th cell in battery box #1 has thermally run away, then V2 to VN must be closed, and only V1 must be kept open.

[0087] c) The battery management system 12 switches pump 1 in the immersion cooling system to jog mode, meaning the time interval between each pump 1 start-up is t1, and the duration of each start-up is t2. t1 can be obtained from multiple module thermal runaway tests, ensuring that the coolant 6 above the battery cell does not completely evaporate due to absorbing heat generated by the battery cell's thermal runaway within this time interval; t2 can be calculated using the following formula:

[0088]

[0089] The pump's rated flow rate is given. L is the length of the space above the battery cell, W is the width of the space above the battery cell, and H is the height of the space above the battery cell. See the detailed dimensions of battery box 9 in the diagram. Figure 2 As shown, c is the safety factor, which can be taken as 1.1 to 1.3, to prevent a small amount of coolant 6 from overflowing from the explosion-proof valve during jogging. This ensures that the area above the thermal runaway battery cell is always covered by coolant 6 during pump 1 jogging.

[0090] In step c) above, the reason why pump 1 switches to jogging mode when the battery cell experiences thermal runaway is as follows: When the battery cell experiences thermal runaway, the gas pressure generated by the large amount of smoke ejected from the corresponding battery box due to the opening of the thermal runaway battery cell's safety valve and the evaporation of coolant 6 accumulates to a certain value. At this point, the explosion-proof valve above the corresponding battery box will open, connecting the battery box to the outside. If pump 1 continues to operate continuously, a large amount of coolant 6 will be ejected from the opened explosion-proof valves K1 to KN within a short period, thus weakening the fire-fighting cooling effect. Therefore, the jogging mode can maximize the use of the coolant 6 stored in the pressure stabilizing tank 5 in the immersion cooling system to suppress the thermal runaway behavior of the battery cell 10, extending the time available for relevant personnel to handle the fire.

[0091] The above specific embodiments further illustrate the technical problems solved by the present invention, the technical solutions, and the beneficial effects. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An immersed thermal energy storage battery thermal management system, characterized by, The application relates to an immersion type thermal management system for energy storage batteries, comprising: a battery cabinet (11) comprising at least one battery box (9) containing a plurality of battery cells (10) immersed in cooling liquid (6); an immersion type circulation system connected to the battery box (9) respectively; a battery management system (12) for determining whether the battery cell (10) has an irreversible thermal runaway phenomenon and controlling the immersion type circulation system to intermittently pump the cooling liquid (6) into the battery box (9) where the battery cell (10) having the irreversible thermal runaway phenomenon is located, wherein the battery cell (10) having the thermal runaway phenomenon is always covered by the cooling liquid (6) in the time interval between two times of pumping the cooling liquid (6); the cooling liquid (6) is intermittently pumped into the battery box (9) where the battery cell (10) is located by the pump (1), and the time interval between two times of pumping the cooling liquid (6) is obtained by formula (1) , Equation (1); wherein, For the rated flow of the pump, L is the length of the space above the battery cell, W is the width of the space above the battery cell, H is the height of the space above the battery cell, and c is a safety factor, which is 1.1-1.

3.

2. The immersion type thermal management system for energy storage batteries according to claim 1, wherein the immersion type circulation system comprises: an electromagnetic valve connected to the cooling liquid inlet of the battery box (9); a cooling liquid pipeline provided with a return liquid pipeline (8), a liquid supply pipeline (7), a pump (1) and a tank (5), the liquid supply pipeline (7) is connected to the electromagnetic valve, and the cooling liquid outlet of the battery box (9) is connected to the return liquid pipeline (8); wherein the battery management system (12) controls the corresponding electromagnetic valve to control the pumping of the cooling liquid (6) into the corresponding battery box (9); the battery management system (12) controls the amount of the cooling liquid pumped into the corresponding battery box (9) by the pump (1).

3. The immersion type thermal management system for energy storage batteries according to claim 2, wherein the cooling liquid pipeline is further provided with an external heat exchange device (2) for heat exchange with the cooling liquid.

4. The immersion type thermal management system for energy storage batteries according to claim 2, wherein the liquid supply pipeline (7) is provided with a liquid supply pressure sensor (3); and / or the return liquid pipeline (8) is provided with a return liquid pressure sensor (4).

5. The immersion type thermal management system for energy storage batteries according to claim 2, wherein a one-way valve is connected between the cooling liquid outlet of the battery box (9) and the return liquid pipeline (8).

6. The immersion type thermal management system for energy storage batteries according to claim 1, wherein an explosion-proof valve is arranged at the upper end of the battery box (9); an alarm sensor is arranged above the battery cabinet (11) and connected to the battery management system (12); the alarm sensor is adapted to trigger an alarm to send an alarm signal and transmit the alarm signal to the battery management system (12); the alarm sensor is a smoke alarm and / or a combustible gas detector; wherein the smoke alarm is adapted to be triggered by the gas sprayed out of the battery box (9) to send an alarm signal when the gas pressure in the battery box (9) accumulates to a certain value. The combustible gas detector is adapted to trigger an alarm to emit an alarm signal when the concentration of combustible gas in the battery cabinet (11) reaches a certain value. 7.The immersion energy storage battery thermal management system of claim 6, wherein, The battery management system (12) is further configured to monitor the surface temperature of the battery cell (10) in real time, calculate the rate of change of the surface temperature of the battery cell (10) with respect to time, and determine the working state of the battery box based on the real-time monitored surface temperature of the battery cell (10), the rate of change of the surface temperature of the battery cell (10) with respect to time, and the alarm signal. 8.The immersion energy storage battery thermal management system of claim 1, wherein, The battery management system (12) sends an alarm message according to the determination of the battery cell.

9. A fire control method characterized by, The method is applied to the battery cabinet (11), the battery cabinet (11) comprises at least one battery box (9), the battery box (9) contains a plurality of battery cells (10) immersed in the cooling liquid (6), the method is implemented based on the immersion energy storage battery thermal management system of any one of claims 1 to 8, and the steps of the method comprise: When an irreversible thermal runaway phenomenon occurs in a certain battery cell (10), the cooling liquid (6) is intermittently pumped into the battery box (9) where the battery cell (10) is located; wherein, during the time interval between each two times of pumping the cooling liquid (6), the cooling liquid (6) is always ensured to cover the battery cell (10) where the thermal runaway phenomenon occurs. 10.The fire control method of claim 9, wherein, The determination condition of the irreversible thermal runaway phenomenon of the battery cell (10) is that: The battery cabinet (11) smokes or alarms for combustible gas, the surface temperature of the battery cell (10) is greater than 60℃, and the rate of change of the surface temperature of the battery cell with respect to time is greater than 1℃ / s. 11.The fire control method of claim 9, wherein, The battery cabinet (11) comprises a plurality of battery boxes (9); When an irreversible thermal runaway phenomenon occurs in a certain battery cell (10), the position of the battery cell (10) where the thermal runaway phenomenon occurs is located, the battery box (9) where the battery cell (10) is located is determined, and the pumping of the cooling liquid (6) into other battery boxes (9) is stopped.

12. A fire control method characterized by, The method is applied to the battery cabinet (11), the battery cabinet (11) comprises at least one battery box (9), the battery box (9) contains a plurality of battery cells (10) immersed in the cooling liquid (6), and the steps of the method comprise: When an irreversible thermal runaway phenomenon occurs in a certain battery cell (10), the cooling liquid (6) is intermittently pumped into the battery box (9) where the battery cell (10) is located; wherein, during the time interval between each two times of pumping the cooling liquid (6), the cooling liquid (6) is always ensured to cover the battery cell (10) where the thermal runaway phenomenon occurs. The method is implemented based on the immersion energy storage battery thermal management system of any one of claims 2 to 5; An explosion-proof valve is arranged at the upper end of the battery box (9); The battery cabinet (11) is provided with an alarm sensor above the battery cabinet (11), and the alarm sensor is connected with the battery management system (12); the alarm sensor is adapted to trigger an alarm to send an alarm signal and transmit the alarm signal to the battery management system (12); The alarm sensor is a smoke alarm and / or a combustible gas detector; wherein, The smoke alarm is adapted to be triggered by the gas sprayed out of the battery box (9) when the gas pressure inside the battery box (9) accumulates to a certain value to send an alarm signal; The combustible gas detector is adapted to trigger an alarm when the concentration of combustible gas in the battery cabinet (11) reaches a certain value to send an alarm signal; The battery management system (12) is also used for monitoring the surface temperature of the battery cell (10) in real time and calculating the rate of change of the surface temperature of the battery cell (10) with time, determining the working state of the battery box according to the real-time monitoring of the surface temperature of the battery cell (10), the rate of change of the surface temperature of the battery cell (10) with time and the alarm signal; When the battery management system (12) does not receive the alarm signal and the surface temperature of the battery cell (10) and the rate of change of the surface temperature of the battery cell (10) with time are normal, the submerged energy storage battery thermal management system keeps normal operation: at this time, all electromagnetic valves are opened, and the pump (1) operates according to the rated working condition; When the battery management system (12) receives the alarm signal and the surface temperature of the battery cell (10) and the rate of change of the surface temperature of the battery cell (10) with time are normal, at this time, the battery management system (12) sends an alarm signal to remind the relevant personnel to go to the scene to check the situation, the electromagnetic valve still keeps the state of being fully opened, and the pump (1) still operates according to the rated working condition; When the battery management system (12) does not receive the alarm signal, but monitors that the surface temperature of the battery cell (10) is abnormal or the rate of change of the surface temperature of the battery cell (10) with time is abnormal, it is determined that the battery cell (10) is in the initial stage of thermal runaway, the battery management system (12) sends an alarm signal, at the same time, the electromagnetic valve still keeps the state of being fully opened, and the frequency of the pump (1) is adjusted to increase the flow and speed up the heat exchange and cooling of the battery cell (10) inside the battery box (9); when the battery management system (12) monitors that the surface temperature of the battery cell (10) and the rate of change of the surface temperature of the battery cell (10) with time are normal, the alarm signal is cancelled, and the frequency of the pump (1) is adjusted to the rated working condition.

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