Immersed type energy storage battery fire extinguishing system

Abstract

The invention provides an immersed energy storage battery fire extinguishing system which comprises a battery pack, a liquid storage tank, a high-pressure storage tank and a controller, the liquid storage tank is connected with a liquid inlet and a liquid outlet of the battery pack through pipelines, cooling liquid is stored in the liquid storage tank, and the battery pack is further connected with the high-pressure storage tank through a pipeline; a proportional valve is mounted on a pipeline for connecting the liquid storage tank with a liquid inlet of the battery pack, a temperature sensor is arranged in the battery pack, and a gas booster pump is mounted on a pipeline for connecting the high-pressure storage tank with the battery pack; the battery pack, the proportional valve, the temperature sensor and the gas booster pump are all electrically connected with the controller. The fire extinguishing system for the immersed energy storage battery can effectively prevent chemical reaction in the battery, quickly and efficiently prevent thermal runaway from continuing and spreading, and improves the use safety of the energy storage battery.

Description

Technical Field

[0001] This invention relates to the technical field of lithium battery thermal management, and more specifically to a submerged energy storage battery fire protection system. Background Technology

[0002] Lithium-ion batteries possess advantages such as high energy density, low self-discharge rate, long cycle life, and environmental friendliness, making them widely used in electric vehicles and energy storage power stations. However, under conditions of abuse such as overcharging, over-discharging, internal short circuits, mechanical damage, and high temperatures, lithium-ion batteries are prone to triggering violent exothermic chemical reactions. Furthermore, to improve energy density, individual cells are often connected in series and parallel to form battery modules, battery packs, and battery clusters. Once a single cell experiences thermal runaway, its temperature rises sharply and it ejects a large amount of flammable gas. The enormous heat and ejected gases released by a single cell's thermal runaway can easily ignite or heat adjacent cells, triggering cascade thermal runaway and causing the entire battery module, cabinet, or even the entire container system to completely lose control within a short period. Therefore, effective thermal management and suppression of thermal runaway are crucial for the safe use of lithium-ion batteries.

[0003] Current fire suppression methods for lithium-ion energy storage batteries primarily rely on the principle of asphyxiation, reducing the oxygen concentration inside the battery pack when overheating is detected. However, this method is largely ineffective against deep-seated chemical reactions within the battery and cannot effectively prevent the continued progression and spread of thermal runaway. The probability of reignition from the inside remains high even after surface fire suppression. Furthermore, existing fire suppression methods only respond after a fire has occurred and cannot prevent thermal runaway in the first place.

[0004] In summary, there is a need in this field for a fire protection system that can effectively prevent and suppress thermal runaway in lithium-ion batteries. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an immersion energy storage battery fire protection system that uses immersion fire protection technology, cools the battery with coolant, and quickly and efficiently suppresses thermal runaway when it occurs, thereby effectively preventing and suppressing the thermal runaway problem of the battery.

[0006] To achieve the above objectives, the present invention provides an immersion-type energy storage battery fire protection system, comprising a battery pack, a liquid storage tank, a high-pressure storage tank, and a controller. The liquid storage tank is connected to the inlet and outlet of the battery pack via pipelines, and stores coolant in the liquid storage tank. The battery pack is also connected to the high-pressure storage tank via pipelines. A proportional valve is installed on the pipeline connecting the liquid storage tank and the inlet of the battery pack. The battery pack contains a temperature sensor. A gas booster pump is installed on the pipeline connecting the high-pressure storage tank and the battery pack. The battery pack, the proportional valve, the temperature sensor, and the gas booster pump are all electrically connected to the controller.

[0007] Preferably, the coolant stored in the reservoir circulates through the battery pack.

[0008] Preferably, when the temperature sensor detects that the temperature of the battery cells inside the battery pack is higher than a set value and reaches a certain duration, the controller controls the battery pack to stop charging and discharging, and the controller adjusts the opening of the proportional valve to regulate the flow rate of coolant into the battery pack, so as to completely submerge the battery cells inside the battery pack.

[0009] Preferably, when the temperature sensor detects that the temperature of the battery cells inside the battery pack is greater than or equal to 65°C and lasts for 10 seconds, the controller controls the battery pack to stop charging and discharging, and the controller adjusts the opening of the proportional valve to regulate the flow rate of coolant into the battery pack, so as to completely submerge the battery cells inside the battery pack.

[0010] Preferably, when the temperature sensor detects that the highest temperature of the battery cell in the battery pack is greater than or equal to the boiling point of the coolant, the coolant near the battery cell will undergo a phase change to form coolant vapor; at the same time, the controller further adjusts the opening of the proportional valve to quickly replenish the evaporated coolant and maintain the state of complete submersion of the battery cell; simultaneously, the controller controls the gas booster pump to start, drawing the coolant vapor inside the battery pack and the combustible mixture generated by the thermal runaway reaction of the battery cell into the high-pressure storage tank.

[0011] Preferably, the top of the high-pressure storage tank is connected to the waste gas treatment device via a pipeline, and an exhaust valve is installed on the pipeline connecting the high-pressure storage tank and the waste gas treatment device. The exhaust valve is electrically connected to the controller. When the pressure inside the high-pressure storage tank reaches a set value, the controller controls the exhaust valve to open, discharging the combustible mixture to the waste gas treatment device.

[0012] Preferably, the battery pack and the liquid storage tank are installed inside the battery cabinet, the high-pressure storage tank is installed outside the battery cabinet, and the high-pressure storage tank is an explosion-proof device.

[0013] Preferably, the battery pack includes a housing, inside which a plurality of battery cells are installed, and inside the housing, a spray liquid distributor is also installed. The spray liquid distributor is installed inside the housing and is located on top of the plurality of battery cells. The liquid inlet of the battery pack is connected to the spray liquid distributor. The spray liquid distributor includes a liquid inlet pipe and a plurality of liquid distribution pipes, all of which are connected to the liquid inlet pipe and are parallel to each other. Each liquid distribution pipe has a plurality of evenly distributed spray holes facing the top of the battery cells.

[0014] Preferably, the spray head is installed in the spray hole with an interference fit, and the coolant is sprayed downward through the spray head; the spray head is made of polyolefin material with a shrinkage temperature of 70°C. When the cell temperature rises and causes the spray head temperature to reach its shrinkage temperature, the spray head shrinks and detaches from the spray hole and falls downward.

[0015] Preferably, a spray head is installed in the spray hole, and the spray head is made of a flame-retardant material that can decompose or undergo phase change with a material conversion temperature between 70-120°C.

[0016] Compared with existing technologies, the advantages of the submerged energy storage battery fire suppression system disclosed in this invention are as follows: the submerged energy storage battery fire suppression system can effectively prevent chemical reactions inside the battery, quickly and efficiently prevent the continuation and spread of thermal runaway, ensure that there is no reignition after fire extinguishing, and improve the safety of energy storage battery use; the submerged energy storage battery fire suppression system can provide early warning and intervention in the early stage of thermal runaway, effectively blocking the runaway process through proactive prevention and control, which helps to reduce losses; the submerged energy storage battery fire suppression system can realize fire suppression function while controlling temperature, integrating the functions of two systems, improving controllability, and reducing the cost of use. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] like Figure 1 The diagram shown is a schematic diagram of a submersible energy storage battery fire protection system according to this application.

[0019] like Figure 2 The diagram shown is a structural schematic of the battery pack of an immersion energy storage battery fire protection system according to this application.

[0020] like Figure 3 The diagram shown is a schematic representation of the sprinkler unit in the battery pack of an immersion energy storage battery fire protection system according to this application.

[0021] like Figure 4 As shown Figure 3 Cross-sectional view along the AA direction.

[0022] like Figure 5 As shown Figure 4 Enlarged schematic diagram of part B. Detailed Implementation

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

[0024] like Figure 1 As shown, this application discloses a submersible energy storage battery fire protection system, which includes a battery pack 1, a liquid storage tank 2, a high-pressure storage tank 3, and a controller. The liquid storage tank 2 is connected to the inlet and outlet of the battery pack 1 via pipelines, and stores coolant in the liquid storage tank 2. The battery pack 1 is also connected to the high-pressure storage tank 3 via pipelines. A proportional valve 12 is installed on the pipeline connecting the liquid storage tank 2 and the inlet of the battery pack 1. The battery pack 1 has a temperature sensor inside, and a gas booster pump 31 is installed on the pipeline connecting the high-pressure storage tank 3 and the battery pack 1. The battery pack 1, the proportional valve 12, the temperature sensor, and the gas booster pump 31 are all electrically connected to the controller.

[0025] The coolant stored in the reservoir 2 circulates through the battery pack 1 under normal operating conditions, dissipating heat from inside the battery pack 1 through convection and maintaining the battery pack 1 at a suitable temperature.

[0026] When the temperature sensor detects that the temperature of the cells inside the battery pack exceeds the set value for a certain period of time, the controller stops charging and discharging battery pack 1. The controller adjusts the opening of proportional valve 12 to regulate the flow rate of coolant into battery pack 1, completely submerging the cells inside battery pack 1. By increasing the heat transfer coefficient and heat transfer area, the heat from the cells is quickly removed. At this time, the cell temperature is controlled within a safe range. The SEI film of the cells has not decomposed, and the negative electrode of the cells has not started to react with the electrolyte, thus actively suppressing the occurrence of thermal runaway. When the temperature sensor detects that the temperature of the cells inside the battery pack is greater than or equal to 65°C for 10 seconds, the controller stops charging and discharging battery pack 1. The controller adjusts the opening of proportional valve 12 to regulate the flow rate of coolant into battery pack 1, completely submerging the cells inside battery pack 1.

[0027] When the temperature sensor detects that the highest temperature of the battery cell inside the battery pack 1 is greater than or equal to the boiling point of the coolant, a large amount of heat is generated by the self-reaction inside the battery cell, and a flammable gas mixture containing CO and H2 is also produced. At this time, the coolant near the thermally runaway battery cell will undergo a phase change to quickly remove the heat from the battery cell, thereby improving the suppression effect of thermal runaway through efficient heat dissipation and stopping the chain exothermic reaction inside the battery cell. At the same time, the controller further adjusts the opening of the proportional valve 12 to quickly replenish the evaporated coolant, ensuring that the battery cell is in a submerged state, and physically isolating the oxygen outside the battery cell through the coolant. Simultaneously, the controller activates the gas booster pump 31 to draw the evaporated coolant vapor inside the battery pack 1 and the flammable gas mixture generated by the thermal runaway reaction of the battery cell into the high-pressure storage tank 3, to prevent the vapor pressure inside the battery pack 1 from rising and causing the boiling point to rise. At the same time, it can quickly discharge the flammable gas mixture that is not dissolved in the coolant to the outside of the battery pack 1, effectively suppressing the spread of heat.

[0028] The submerged energy storage battery fire suppression system can proactively and effectively prevent thermal runaway during the early intervention window, effectively blocking the thermal runaway process. By absorbing and dissipating a large amount of heat through coolant, it rapidly lowers the temperature of the runaway cell below its reaction critical point, halting the internal chain of exothermic reactions. The system effectively prevents internal chemical reactions, quickly and efficiently stopping the continuation and spread of thermal runaway, ensuring no reignition after fire suppression, and improving the safety of energy storage battery use. By proactively preventing and effectively blocking the runaway process, it helps reduce losses. Furthermore, the submerged energy storage battery fire suppression system can simultaneously control temperature and perform fire suppression, integrating the functions of both systems, improving controllability, and reducing operating costs.

[0029] The evaporated coolant vapor is pressurized and enters the high-pressure storage tank 3. The high-pressure storage tank 3 dissipates heat through its outer wall, and the coolant vapor cools down and turns back into a liquid phase. The combustible gas mixture floats on the top of the high-pressure storage tank 3. Preferably, the bottom of the high-pressure storage tank 3 is connected to a coolant recovery device through a pipeline, which can recover the liquid phase of the coolant and help reduce the overall production cost.

[0030] The top of the high-pressure storage tank 3 is connected to the waste gas treatment device via a pipeline. An exhaust valve 32 is installed on the pipeline connecting the high-pressure storage tank 3 and the waste gas treatment device, and the exhaust valve 32 is electrically connected to the controller. When the pressure inside the high-pressure storage tank 3 reaches a set value, the controller controls the exhaust valve 32 to open, discharging the combustible mixture to the waste gas treatment device, preventing the internal pressure of the high-pressure storage tank 3 from becoming too high, and effectively treating the combustible mixture.

[0031] Preferably, the battery pack 1 and the liquid storage tank 2 are installed inside the battery cabinet, and the high-pressure storage tank 3 is installed outside the battery cabinet. The high-pressure storage tank 3 is an explosion-proof device to improve safety.

[0032] The preferred coolant is a fluorinated liquid with a boiling point of 90-120℃. When the maximum cell temperature is lower than the boiling point of the fluorinated liquid, the fluorinated liquid does not undergo a phase change and carries away the heat generated by the cell through convection. When the maximum cell temperature is greater than or equal to the boiling point of the fluorinated liquid, the fluorinated liquid undergoes a phase change and rapidly carries away the heat from the cell.

[0033] See Figure 2 The battery pack 1 includes a housing 10, inside which several battery cells 100 are installed. A coolant sprayer 11 is also installed inside the housing 10, positioned on top of the battery cells 100. The coolant inlet of the battery pack 1 is connected to the coolant sprayer 11. Coolant is sprayed onto the battery cells 100 through the coolant sprayer 11, achieving uniform cooling of the cells 100 and enabling rapid and uniform heat dissipation.

[0034] See Figure 3 and Figure 4 The spray distribution device 11 includes an inlet pipe 111 and several distribution pipes 112. All distribution pipes 112 are connected to the inlet pipe 111 and are parallel to each other. Each distribution pipe 112 has several evenly distributed spray holes 113, which face the top of the battery cell 100. The inlet pipe 111 and the distribution pipes 112 are made of flame-retardant plastic, such as PC or PE. Preferably, the diameter of the spray holes 113 is 10mm to meet the requirement of high-flow-rate spraying of coolant.

[0035] See Figure 5 The spray head 114 is installed in the spray hole 114 with an interference fit. The spray hole diameter of the spray head 114 is smaller than that of the spray hole 113. Coolant is sprayed downward through the spray head 114. The spray head 114 is made of polyolefin material with a shrinkage temperature of about 70°C. When the cell temperature rises and the spray head 114 reaches its shrinkage temperature, the spray head 114 shrinks and detaches from the spray hole 113, falling downward. Coolant is then sprayed downward through the spray hole 113, increasing the spray flow rate and improving the immersion speed of the cell. In addition, for abnormally overheated cells, only the upper part of the spray head 114 is heated. After the corresponding spray head 114 falls, it can enhance convection heat transfer around the abnormal cell, achieving point-to-point management for greater precision and efficiency.

[0036] As a variant, the spray head 114 can also be made of a flame-retardant material that can decompose or undergo phase change with a material conversion temperature between 70-120℃. When the temperature rises, it decomposes or undergoes a phase change, thereby increasing the spray flow rate at the corresponding location.

[0037] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A submersible energy storage battery fire protection system, characterized in that, The system includes a battery pack, a coolant reservoir, a high-pressure storage tank, and a controller. The coolant reservoir is connected to the inlet and outlet of the battery pack via pipelines, and stores coolant. The battery pack is also connected to the high-pressure storage tank via pipelines. A proportional valve is installed on the pipeline connecting the coolant reservoir and the inlet of the battery pack. The battery pack contains a temperature sensor. A gas booster pump is installed on the pipeline connecting the high-pressure storage tank and the battery pack. The battery pack, the proportional valve, the temperature sensor, and the gas booster pump are all electrically connected to the controller.

2. The submersible energy storage battery fire protection system as described in claim 1, characterized in that, The coolant stored in the reservoir circulates through the battery pack.

3. The submersible energy storage battery fire protection system as described in claim 1, characterized in that, When the temperature sensor detects that the temperature of the cells inside the battery pack is higher than the set value and reaches a certain duration, the controller controls the battery pack to stop charging and discharging. The controller adjusts the opening of the proportional valve to regulate the flow rate of coolant into the battery pack, so as to completely submerge the cells inside the battery pack.

4. The submersible energy storage battery fire protection system as described in claim 3, characterized in that, When the temperature sensor detects that the temperature of the cells inside the battery pack is greater than or equal to 65°C for 10 seconds, the controller controls the battery pack to stop charging and discharging. The controller adjusts the opening of the proportional valve to regulate the flow rate of coolant into the battery pack, so as to completely submerge the cells inside the battery pack.

5. The submersible energy storage battery fire protection system as described in claim 1, characterized in that, When the temperature sensor detects that the highest temperature of the battery cell in the battery pack is greater than or equal to the boiling point of the coolant, the coolant near the battery cell will undergo a phase change to form coolant vapor. At the same time, the controller further adjusts the opening of the proportional valve to quickly replenish the evaporated coolant and maintain the battery cell in a completely submerged state. Simultaneously, the controller controls the gas booster pump to start, drawing the coolant vapor inside the battery pack and the combustible mixture generated by the thermal runaway reaction of the battery cell into the high-pressure storage tank.

6. The immersion energy storage battery fire protection system as described in claim 1, characterized in that, The top of the high-pressure storage tank is connected to the waste gas treatment device via a pipeline. An exhaust valve is installed on the pipeline connecting the high-pressure storage tank and the waste gas treatment device. The exhaust valve is electrically connected to the controller. When the pressure inside the high-pressure storage tank reaches a set value, the controller controls the exhaust valve to open, discharging the combustible mixture to the waste gas treatment device.

7. The submersible energy storage battery fire protection system as described in claim 1, characterized in that, The battery pack and the liquid storage tank are installed inside the battery cabinet, and the high-pressure storage tank is installed outside the battery cabinet. The high-pressure storage tank is an explosion-proof device.

8. The immersion energy storage battery fire protection system as described in claim 1, characterized in that, The battery pack includes a housing, inside which several battery cells are installed. A spray distributor is also installed inside the housing, positioned on top of the battery cells. The battery pack's liquid inlet is connected to the spray distributor. The spray distributor includes an inlet pipe and several distribution pipes, all connected to the inlet pipe and parallel to each other. Each distribution pipe has several evenly distributed spray holes facing the top of the battery cells.

9. The submersible energy storage battery fire protection system as described in claim 8, characterized in that, The spray head is installed in the spray hole with an interference fit, and the coolant is sprayed downward through the spray head; the spray head is made of polyolefin material with a shrinkage temperature of 70°C. When the temperature of the battery cell rises and causes the temperature of the spray head to reach its shrinkage temperature, the spray head shrinks and detaches from the spray hole and falls downward.

10. The immersion energy storage battery fire protection system as described in claim 8, characterized in that, Spray heads are installed in the spray holes, and the spray heads are made of flame-retardant materials that can decompose or undergo phase change with a material conversion temperature between 70-120℃.

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