A thermal runaway control method of an immersed energy storage system and the energy storage system

Abstract

The application provides a thermal runaway control method of an immersed energy storage system and the energy storage system, and the energy storage system comprises an immersed tank assembly, a pressure relief assembly and a shell; a pressure relief plate is arranged at an upper corner of a tank body of the immersed tank assembly; a partition plate is arranged in the tank body, so that a chamber in the tank body is divided into an immersion chamber and an overflow chamber, and immersion liquid in the overflow chamber is intermittently discharged; the tank body is connected with a liquid input pipeline, a liquid emptying pipeline, an overflow pipeline, a liquid output pipeline, a fourth valve body and a waste liquid pipe; when thermal runaway occurs in a battery unit, the liquid input pipeline, the liquid emptying pipeline, the overflow pipeline, the liquid output pipeline, the fourth valve body and the waste liquid pipe are used for preventing immersion liquid mixed with electrolyte from entering a circulating system; and a pressure relief channel is used for discharging and relieving gas discharged during thermal runaway. Through intermittent liquid discharge of the overflow chamber, the application can delay the immersion liquid from flowing into the circulating system to a certain extent, so that the leaked electrolyte is prevented from being mixed into the immersion liquid circulation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy storage, in particular to a thermal runaway control method of an immersed energy storage system and the energy storage system. BACKGROUND

[0002] In the field of energy storage, it is crucial to maintain the battery within an appropriate temperature range. Overheating of the battery can affect its performance and lifespan, and even cause safety accidents. In existing technologies, techniques such as air cooling natural regulation and air conditioning regulation are commonly used to control the temperature of the battery. However, air cooling natural regulation is inefficient, and air conditioning regulation consumes a lot of energy. Moreover, it cannot achieve precise temperature control of the battery, and individual battery temperature peaks may be too high, which is not conducive to stable operation of the battery.

[0003] Liquid cooling technology, as a new cooling method in the field of energy storage, is developing rapidly. It has high temperature control efficiency and can achieve precise control of battery temperature. In particular, immersed energy storage technology immerses battery modules in immersion liquid, which can uniformly regulate the surface temperature of the battery and has very high temperature regulation efficiency.

[0004] Chinese patent CN202322534545.8 discloses a fire extinguishing system for an energy storage system and the energy storage system. The fire extinguishing system includes a medicament tank, a liquid inlet pipeline, and a liquid outlet pipeline. The liquid inlet pipeline includes a liquid inlet main pipe and multiple liquid inlet branch pipes. The liquid inlet main pipe is connected to the medicament tank and the multiple liquid inlet branch pipes, respectively. The liquid inlet branch pipes are provided with liquid inlet valves. The liquid outlet pipeline includes multiple liquid outlet branch pipes. The fire extinguishing medium is delivered to the battery pack through the liquid inlet branch pipes, mixed with the electrolyte, and cooled. The mixture of the fire extinguishing medium and the electrolyte is discharged from the energy storage tank through the liquid outlet branch pipes. The fire extinguishing medium is a fire water-based coolant, which has obvious cooling effect and can carry heat away from the battery pack. Since the liquid inlet and liquid outlet are performed simultaneously, the gas in the battery pack will not increase sharply to cause the safety valve to open, thereby avoiding the combustible gas generated by thermal runaway from leaking out of the safety valve and causing a fire outside the battery pack. In addition, the patent can also prevent the waste liquid in the battery pack from flowing out of the safety valve and polluting other battery packs. The patent can to some extent avoid the leakage of combustible gas from the battery pack and the resulting fire. However, some batteries on the market can rapidly and violently react when they experience thermal runaway. The above patent cannot completely eliminate the above risks. When the battery pack leaks, the patent cannot effectively reduce the damage caused by the leakage. In particular, in an immersed energy storage system, when the battery experiences thermal runaway and leaks electrolyte, the leaked electrolyte will quickly pollute the entire system along with the flow of the immersion liquid, causing significant damage. SUMMARY

[0005] The problem solved by the present application is that in the prior art, when the battery leaks electrolyte due to thermal runaway in the submerged energy storage system, the leaked electrolyte will quickly contaminate the entire system along with the flow of the immersion liquid, causing significant damage.

[0006] To solve the above problems, the present application discloses an energy storage system, which is a submerged energy storage system, comprising:

[0007] The immersion tank assembly comprises a tank body and a battery unit, the battery unit is arranged in the tank body, a circulating flow immersion liquid is arranged in the tank body, and the battery unit is completely immersed in the immersion liquid;

[0008] The pressure relief assembly is arranged on the upper side of the tank body and is in sealed connection with the tank body, a pressure relief channel is formed between the pressure relief assembly and the top of the tank body, and at least one end of the pressure relief channel is connected with the shell of the energy storage system;

[0009] The shell is provided with a ventilation part at a position corresponding to the pressure relief assembly;

[0010] The pressure relief plate is rotatably connected with the top cover or the side wall of the tank body, and the pressure relief plate can be opened to discharge the gas in the tank body and can be closed to seal the tank body; a partition plate is arranged in the tank body, the partition plate is used to separate the internal cavity of the tank body into an immersion cavity and an overflow cavity, the top end of the partition plate is spaced apart from the inner wall of the tank top plate, so that the immersion cavity and the overflow cavity are communicated above the partition plate, the immersion cavity is connected with a liquid input pipeline for inputting the immersion liquid into the immersion cavity, the immersion cavity is also connected with a liquid output pipeline for discharging the immersion liquid in the immersion cavity, the overflow cavity is connected with an overflow pipeline, a fifth valve body is arranged on the overflow pipeline, the fifth valve body is used to intermittently discharge the immersion liquid in the overflow cavity, the overflow pipeline is connected with the liquid output pipeline for the circulating flow of the immersion liquid, and the liquid output pipeline is also connected with a waste liquid pipe connected with a waste liquid tank, a fourth valve body is arranged on the waste liquid pipe, and the fourth valve body is used to control the on-off of the waste liquid pipe;

[0011] When the battery unit experiences thermal runaway, the liquid input pipeline, the liquid emptying pipeline, the overflow pipeline, the liquid output pipeline, the fourth valve body and the waste liquid pipe are used to prevent the immersion liquid mixed with electrolyte from entering the circulating system, and the pressure relief channel and the pressure relief plate are used to cooperate to discharge the gas discharged during thermal runaway.

[0012] Further, the included angle between the pressure relief plate and the side wall of the tank body is α, and the value of α is 20°-40°.

[0013] Further, a toxic gas prevention structure is arranged at a position close to the shell of the pressure relief channel, and the toxic gas prevention structure is used to absorb toxic gas released when the battery cell is in thermal runaway.

[0014] Further, an inclined waterproof plate is arranged on the bottom plate of the pressure relief channel inside the shell, the waterproof plate is arranged between the shell and the toxic gas prevention structure, and the waterproof plate is arranged gradually away from the shell from bottom to top, a water drainage part is arranged at a connecting position of the shell and the bottom of the pressure relief channel, and the water drainage part is used to drain water blocked by the waterproof plate.

[0015] Further, the waterproof plate comprises a water guide slope and a waterproof main plate, the water guide slope is arranged between the shell and the waterproof main plate, and the water guide slope is arranged gradually raised from one end close to the shell to one end connected with the waterproof main plate, and the waterproof main plate is arranged inclined gradually away from the shell from bottom to top.

[0016] Further, the upper end of the waterproof main plate is spaced apart from the inner wall surface of the upper side of the pressure relief channel.

[0017] Further, a one-way movable plate is arranged on the waterproof main plate, the one-way movable plate is rotationally connected with the waterproof main plate, and the one-way movable plate can be rotated to open in the direction of the shell under a certain air pressure, so as to connect the spaces on both sides of the waterproof main plate.

[0018] The application further discloses a thermal runaway control method of an energy storage system, which is used for the energy storage system and comprises the following steps:

[0019] Step ST1: detecting a temperature rise rate v1 of a battery cell in the energy storage system and an air pressure value P1 on the upper side of an immersion cavity;

[0020] Step ST2: comparing the temperature rise rate v1 of the battery cell with a preset temperature rise rate v2, comparing the air pressure value P1 on the upper side of the immersion cavity with a preset pressure threshold value P2, when at least one of the comparison results satisfies v1≥v2 and P1≥P2, it is judged that the current battery cell is in thermal runaway, an alarm signal is sent, and step ST3 is executed, and when the comparison results satisfy v1<v2 and P1<P2, it is judged that the current battery cell is in normal operation, and step ST1 is returned to be executed;

[0021] Step ST3: cutting off the power supply of the current battery cell, closing the liquid input pipeline, the overflow pipeline and the liquid output pipeline of the immersion tank assembly corresponding to the current battery cell, and discharging high-pressure gas in the immersion tank assembly corresponding to the current battery cell through the pressure relief plate;

[0022] Step ST4: continuously detecting the temperature change of the battery cell in thermal runaway and the air pressure value in the immersion tank assembly where the battery cell is located;

[0023] Step ST5: When the temperature of the battery unit that has thermal runaway falls below the first preset temperature threshold Q1, and the value of the air pressure in the immersion tank assembly in which it is located is less than the preset pressure threshold P2, step ST6 is performed:

[0024] Step ST6: Turn on the overflow pipeline, liquid evacuation pipeline and waste liquid pipeline to drain the immersion liquid inside the immersion tank assembly in which the battery unit that has thermal runaway is located to the waste liquid tank.

[0025] Further, the preset temperature rise rate v2 is between 1.8℃ / s and 2.2℃ / s; and the preset pressure threshold P2 is between 118KPa and 122KPa.

[0026] Further, in step S5, the first preset temperature threshold Q1 is between 50℃ and 60℃.

[0027] Compared with the prior art, the thermal runaway control method of the immersion energy storage system and the energy storage system have the following advantages:

[0028] By arranging the partition plate in the immersion tank, the space in the immersion tank is divided into an upper immersion cavity and an overflow cavity that are connected in communication, and by intermittently draining the overflow cavity, the immersion liquid can be delayed from flowing into the circulating system to some extent, so that the leaked electrolyte can be effectively prevented from mixing into the immersion liquid circulating system, thereby preventing the immersion liquid in other immersion tank assemblies from being contaminated, and significantly reducing the loss caused by battery thermal runaway. In addition, by arranging the pressure relief assembly, the gas generated during thermal runaway can be quickly discharged, further reducing the risk caused by battery thermal runaway. The thermal runaway control method provided by the present application can effectively prevent the influence of electrolyte on the immersion liquid, and significantly reduce the loss caused by thermal runaway to the immersion energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 FIG. 1 is a perspective view of an immersion tank assembly according to an embodiment of the present application;

[0030] Figure 2 FIG. 2 is a perspective view of the immersion tank assembly from another angle according to an embodiment of the present application;

[0031] Figure 3 FIG. 3 is a sectional view of the immersion tank assembly according to an embodiment of the present application;

[0032] Figure 4 FIG. 4 is a sectional view of the immersion tank assembly from another angle according to an embodiment of the present application;

[0033] Figure 5 FIG. 5 is a partial sectional view of the immersion tank assembly, the pressure relief channel and the housing of the energy storage system according to an embodiment of the present application;

[0034] Figure 6 A perspective view of the temperature regulating device according to an embodiment of the present application;

[0035] Figure 7 A perspective view of the temperature regulating device according to an embodiment of the present application from another angle;

[0036] Figure 8 A front view of the temperature regulating device according to an embodiment of the present application;

[0037] Figure 9 A perspective view of the temperature regulating device according to an embodiment of the present application; Figure 8 A cross-sectional view of the temperature regulating device according to an embodiment of the present application along A-A when the first magnetic body is attached to the outer peripheral wall of the heat exchange structure;

[0038] Figure 10 A cross-sectional view of the temperature regulating device according to an embodiment of the present application along B-B when the first magnetic body is attached to the outer peripheral wall of the heat exchange structure; Figure 8 A cross-sectional view of the temperature regulating device according to an embodiment of the present application along B-B when the second magnetic body is attached to the outer peripheral wall of the heat exchange structure;

[0039] Figure 11 A cross-sectional view of the temperature regulating device according to an embodiment of the present application along B-B when the second magnetic body is attached to the outer peripheral wall of the heat exchange structure; Figure 8 A cross-sectional view of the temperature regulating device according to an embodiment of the present application along B-B when the second magnetic body is attached to the outer peripheral wall of the heat exchange structure;

[0040] Figure 12 A perspective view of the connection between the immersion tank assembly and the temperature regulating device according to an embodiment of the present application;

[0041] Figure 13 A perspective view of the immersion tank assembly according to an embodiment of the present application with a second tank body arranged outside;

[0042] Figure 14 A cross-sectional view of the immersion tank assembly according to an embodiment of the present application with a second tank body arranged outside;

[0043] Figure 15 A perspective view of the second tank body and the liquid receiving disc according to an embodiment of the present application.

[0044] Explanation of reference signs:

[0045] 100, immersion tank assembly; 110, tank body; 111, liquid inlet hole; 120, battery unit; 130, partition; 140, immersion cavity; 150, overflow cavity; 160, liquid input part; 161, liquid input pipeline; 1611, first valve body; 162, liquid emptying pipeline; 1621, second valve body; 163, overflow pipeline; 1631, fifth valve body; 164, liquid inlet cavity; 165, liquid inlet slope; 166, liquid output pipeline; 1661, third valve body; 170, turbulence vane; 180, drying part; 190, pressure relief plate; 200, pressure relief assembly; 210, pressure relief channel; 220, waterproof plate; 230, anti-poison structure; 221, water guide slope; 222, waterproof main plate; 223, one-way movable plate; 300, shell; 310, ventilation part; 320, drainage part; 400, temperature adjusting device; 410, temperature adjusting box; 420, external magnet; 430, internal magnet; 440, heat exchange structure; 441, liquid inlet; 442, liquid outlet; 443, heat exchange cavity; 450, fin; 460, first magnetically susceptible body; 470, second magnetically susceptible body; 480, slide rail; 500, waste liquid tank; 510, waste liquid pipe; 520, fourth valve body; 600, pump body; 700, second tank body; 710, liquid receiving disc; 711, recessed groove; 712, step part; 713, liquid discharge pipe. DETAILED DESCRIPTION

[0046] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0047] A heat runaway control method of an immersion energy storage system and the energy storage system are specifically described below.

[0048] The present embodiment provides an immersion energy storage system, and the energy storage system is an immersion energy storage system, as shown in Figures 1-15 The immersion energy storage system comprises:

[0049] The immersion tank assembly 100 comprises a tank body 110 and a battery unit 120, the battery unit 120 is arranged in the tank body 110, circulating flow immersion liquid is arranged in the tank body 110, and the battery unit 120 is completely immersed in the immersion liquid;

[0050] A pressure relief assembly 200 is arranged on the upper side of the box body 110 and is sealingly connected with the box body 110, forming a pressure relief channel 210 between the pressure relief assembly 200 and the top of the box body 110, at least one end of the pressure relief channel 210 being connected with the shell 300 of the energy storage system;

[0051] A shell 300 is provided with a ventilation portion 310 corresponding to the position of the pressure relief assembly 200;

[0052] A pressure relief plate 190 is arranged at the upper corner of the side of the box body 110 away from the partition plate 130, and is rotatably connected with the top cover or side wall of the box body 110, and can be opened to discharge the gas in the box body 110 and can be closed to seal the box body 110; a partition plate 130 is arranged in the box body 110, and is used to divide the internal cavity of the box body 110 into an immersion cavity 140 and an overflow cavity 150, the top end of the partition plate 130 being spaced apart from the inner wall of the top plate of the box body 110, so that the immersion cavity 140 and the overflow cavity 150 are in communication at the upper portion of the partition plate 130, the immersion cavity 140 is connected with a liquid input pipeline 161 for inputting immersion liquid into the immersion cavity 140, the immersion cavity 140 is also connected with a liquid emptying pipeline 162 for discharging the immersion liquid in the immersion cavity 140, the overflow cavity 150 is connected with an overflow pipeline 163, a fifth valve body 1631 is arranged on the overflow pipeline 163, and the fifth valve body 1631 is used to intermittently discharge the immersion liquid in the overflow cavity 150, the overflow pipeline 163 is connected with a liquid output pipeline 166 for the circulating flow of the immersion liquid, and the liquid output pipeline 166 is also connected with a waste liquid pipe 510 connected with a waste liquid tank 500, a fourth valve body 520 is arranged on the waste liquid pipe 510, and the fourth valve body 520 is used to control the on-off of the waste liquid pipe 510;

[0053] When the battery cell 120 occurs thermal runaway, the liquid input pipeline 161, the liquid emptying pipeline 162, the overflow pipeline 163, the liquid output pipeline 166, the fourth valve body 520 and the waste liquid pipe 510 are used to prevent the immersion liquid mixed with the electrolyte from entering the circulating system, and the pressure relief channel 210 and the pressure relief plate 190 are used to cooperate to discharge the gas discharged during thermal runaway.

[0054] It should be understood that the energy storage system using immersion cooling can reduce the probability of thermal runaway of the battery cell 120 and the risk it brings to a certain extent, and basically will not catch fire, but when the battery cell 120 is in thermal runaway, it will produce a large amount of gas in addition to electrolyte leakage, causing the internal gas pressure of the tank 110 to rise rapidly, which poses a considerable safety hazard. Through the above setting, when the battery cell 120 in the immersion tank assembly 100 is in thermal runaway, the pressure relief plate 190 can be opened, the gas generated by thermal runaway is transported into the pressure relief channel 210, and then discharged through the ventilation part 310, thereby effectively reducing the gas pressure in the immersion tank assembly 100, and further reducing the risk brought by the thermal runaway battery cell 120. It should be understood that one pressure relief assembly 200 can be connected with more than one immersion tank assembly 100, thereby realizing the control of more than one immersion tank assembly 100 in thermal runaway. In addition, the lower end of the pressure relief plate 190 is connected to a plane with a height higher than the height of the top end of the partition plate 130, which is used to prevent immersion liquid from leaking from the connection position of the pressure relief plate 190, and the fifth valve body 1631 is used to control the opening and closing of the overflow pipeline 163. It should be understood that under normal operating conditions, the overflow pipeline 163 does not need to be provided with a valve body, but when the battery cell 120 is in thermal runaway, electrolyte leakage is prone to occur, at which time the overflow pipeline 163 is prone to transport the immersion liquid mixed with the electrolyte of the battery cell 120 to the immersion liquid circulation system, and the setting of the fifth valve body 1631 facilitates the intermittent drainage of the overflow cavity 150. When the immersion liquid overflowing into the overflow cavity 150 reaches a certain liquid level, the fifth valve body 1631 is opened, and the immersion liquid in the overflow cavity 150 is discharged, wherein the certain liquid level is a preset liquid level, which is not limited herein. It should be understood that the battery cell 120 in the embodiment is a battery monomer or a battery module. It should be noted that the immersion liquid used in the present application is the immersion liquid commonly used in the current immersion energy storage system, such as fluorinated liquid, which will not be repeated and limited herein.

[0055] Specifically, a first valve body 1611 is arranged on the liquid input pipeline 161, and is used to control the opening and closing of the liquid input pipeline 161; a second valve body 1621 is arranged on the liquid emptying pipeline 162, and is used to control the opening and closing of the liquid emptying pipeline 162; a third valve body 1661 is arranged on the liquid output pipeline 166, and is used to control the opening and closing of the liquid output pipeline 166; and the connection point of the waste liquid pipeline 510 and the liquid output pipeline 166 is located on the upstream side of the third valve body 1661. Through the above arrangement, in normal operation, the first valve body 1611 and the third valve body 1661 are opened, the second valve body 1621, the fourth valve body 520 are closed, and the fifth valve body 1631 is intermittently opened or closed, so that the intermittent circulation of the immersion liquid can be realized; when maintenance is needed, the first valve body 1611 is closed, the fourth valve body 520 remains closed, and the second valve body 1621, the third valve body 1661 and the fifth valve body 1631 are opened, so that the immersion liquid can be emptied. When it is detected that the battery unit 120 has thermal runaway, the immersion liquid containing the electrolyte will not be mixed into the immersion liquid of other normally operating immersion tank assemblies 100 at the first time, but will be retained in the overflow chamber 150. At this time, through the cooperation control of the first valve body 1611, the second valve body 1621, the third valve body 1661, the fourth valve body 520 and the fifth valve body 1631, such as closing all the above valve bodies, the immersion liquid in the immersion tank assembly 100 that has leaked electrolyte can be completely imprisoned. Under suitable conditions, the first valve body 1611 and the third valve body 1661 remain closed, and the second valve body 1621, the fourth valve body 520 and the fifth valve body 1631 are all opened, so that the immersion liquid mixed with the electrolyte can be completely discharged, so as to replace the new battery unit 120 or the immersion liquid, thereby effectively reducing the safety hazard and the loss of the immersion liquid caused by the thermal runaway.

[0056] As one of the preferred embodiments, the included angle between the pressure relief plate 190 and the side wall of the tank body 110 is α, and the value of α is 20°-40°, and preferably, α is 30°. Through the above arrangement, when the pressure relief plate 190 is rotationally connected with the side wall of the tank body 110, it can be opened through a smaller force, and the flow of gas in the pressure relief channel 210 will not be affected.

[0057] In the embodiment, a barometer (not shown in the figure) is arranged above the immersion chamber 140, and is used to detect the pressure of the air on the upper side of the immersion chamber 140. Preferably, the barometer is linked with the pressure relief plate 190 for linkage control, and is used to open the pressure relief plate 190 to release pressure when the pressure rises to a certain degree. In addition, the barometer can also not be arranged, and the pressure relief plate 190 can also be pushed away by the gas when it bears a certain air pressure, so as to achieve the purpose of pressure relief.

[0058] As one of the preferred embodiments, the anti-toxic structure 230 is arranged near the shell 300, which is used to absorb the toxic gas released when the battery unit 120 is in thermal runaway. It should be understood that a large amount of toxic gas will be released when the battery unit 120 is in thermal runaway, and directly discharging it will cause serious damage to the environment. By arranging the anti-toxic structure 230, some of the toxic gas can be removed, reducing the damage. It should be noted that the anti-toxic structure 230 can adopt a porous structure, in which activated carbon, chemisorbent such as activated carbon impregnated with copper sulfate, and other substances are arranged, so as to reduce the content of toxic gas when the gas passes through. As one of the preferred embodiments, the anti-toxic structure 230 has two or more, and the air holes on the two or more anti-toxic structures 230 gradually increase from the side close to the shell 300 to the side close to the immersion tank assembly 100. This arrangement can achieve step-by-step removal of toxic gas, thereby significantly improving the removal effect and reducing the pollution of the gas emitted by thermal runaway to the environment.

[0059] In another optional embodiment, an inclined waterproof plate 220 is arranged on the bottom plate of the pressure relief channel 210 inside the shell 300, the waterproof plate 220 is arranged between the shell 300 and the anti-toxic structure 230, and the waterproof plate 220 is arranged away from the shell 300 from bottom to top, and a drainage part 320 is arranged at the connection position of the shell 300 and the bottom of the pressure relief channel 210, which is used to drain the water blocked by the waterproof plate 220. It should be understood that in rainy and snowy weather, rain and snow water is easy to enter the pressure relief channel 210 through the ventilation part 310, affecting the normal operation of the immersion tank assembly 100. The arrangement of the waterproof plate 220 can effectively block the water entering the pressure relief channel 210, ensuring the normal operation of the energy storage system.

[0060] Specifically, the waterproof plate 220 includes a water guide slope 221 and a waterproof main plate 222, the water guide slope 221 is arranged between the shell 300 and the waterproof main plate 222, and the water guide slope 221 is arranged gradually higher from one end close to the shell 300 to the end connected with the waterproof main plate 222, and the waterproof main plate 222 is arranged inclined away from the shell 300 from bottom to top. This arrangement facilitates the rapid drainage of water entering the pressure relief channel 210, avoiding the accumulation of water in the pressure relief channel 210, affecting the normal operation of the immersion tank assembly 100.

[0061] Preferably, the upper end of the waterproof main plate 222 has a certain spacing with the inner wall surface of the upper side of the pressure relief channel 210. This arrangement facilitates the airflow to flow from the upper side of the waterproof main plate 222.

[0062] In one preferred embodiment, a one-way movable plate 223 is arranged on the waterproof main plate 222, which is rotationally connected with the waterproof main plate 222 and can be rotated to open in the direction of the shell 300 under a certain air pressure to connect the spaces on both sides of the waterproof main plate 222. It should be understood that when the battery cell 120 occurs thermal runaway, a large amount of gas is generated to rapidly increase the air pressure, and after the gas is discharged into the pressure relief channel 210, if the gas flows out from the upper end of the waterproof main plate 222, the flow rate is limited, which can cause the air pressure in the pressure relief channel 210 to rapidly rise, and there is a certain risk. Through the arrangement of the one-way movable plate 223, the gas inside the waterproof main plate 222 can be directly discharged when the pressure is large, which significantly increases the air outlet speed and avoids the increase of the pressure.

[0063] As one optional embodiment, the angle between the waterproof main plate 222 and the bottom plate of the pressure relief channel 210 is denoted as β, and the value of β is in the range of 50°-70°. Preferably, the value of β is 60°. Specifically, the upper end of the one-way movable plate 223 is rotationally connected with the waterproof main plate 222, and a stepped surface is arranged on the waterproof main plate 222 near the lower end of the one-way movable plate 223, which abuts against the one-way movable plate 223 to prevent it from rotating in the direction of the submerged tank assembly 100. Through the above arrangement, the one-way movable plate 223 can be pushed by a relatively small air pressure, so that it can effectively relieve the pressure and reduce the risk caused by the thermal runaway of the battery cell 120.

[0064] On this basis, the embodiment also provides a thermal runaway control method of a submerged energy storage system, which includes the following steps:

[0065] The thermal runaway control method includes the following steps:

[0066] Step ST1: detecting the temperature rise rate v1 of the battery cell in the energy storage system and the air pressure value P1 on the upper side of the submerged cavity;

[0067] Step ST2: comparing the temperature rise rate v1 of the battery cell with a preset temperature rise rate v2 and comparing the air pressure value P1 on the upper side of the submerged cavity with a preset pressure threshold P2, when at least one of the comparison results satisfies v1≥v2 and P1≥P2, it is judged that the current battery cell occurs thermal runaway, an alarm signal is issued, and step ST3 is executed; when the comparison results satisfy v1<v2 and P1<P2, it is judged that the current battery cell operates normally, and step ST1 is returned to be executed;

[0068] Step ST3: cut off the power supply of the current battery cell, close the liquid input pipeline, overflow pipeline and liquid output pipeline of the current battery cell corresponding to the immersion tank assembly, and discharge the high-pressure gas in the current battery cell corresponding to the immersion tank assembly through the pressure relief plate. Specifically, the operation mode of closing the pipeline is to close the first valve body 1611, the fifth valve body 1631 and the third valve body 1661. The second valve body 1621 and the fourth valve body 520 are normally closed valves, which remain closed. The exhaust through the pressure relief plate 190 can be achieved by opening the pressure relief plate 190 or opening the pressure relief plate 190 and the one-way movable plate 223. The opening of the pressure relief plate 190 or the pressure relief plate 190 and the one-way movable plate 223 can be automatically lifted by the internal pressure or controlled by the corresponding control module. The specific structure can refer to the prior art, which is not limited here.

[0069] Step ST4: continuously detect the temperature change of the battery cell that has occurred thermal runaway and the pressure value in the immersion tank assembly where it is located;

[0070] Step ST5: when the temperature of the battery cell that has occurred thermal runaway falls below the first preset temperature threshold Q1, and the pressure value in the immersion tank assembly where it is located is less than the preset pressure threshold P2, execute step ST6:

[0071] Step ST6: turn on the overflow pipeline, liquid emptying pipeline and waste liquid pipeline to discharge the immersion liquid in the immersion tank assembly where the thermal runaway battery cell is located to the waste liquid tank. The specific operation method is to open the second valve body 1621, the fourth valve body 520 and the fifth valve body 1631, and the first valve body 1611 and the third valve body 1661 remain closed. Since the pressure relief plate 190 is also in the open state at this time, the immersion liquid in the immersion tank assembly 100 can be quickly discharged to the waste liquid tank 500.

[0072] It should be understood that when the battery unit 120 is in thermal runaway, its temperature will rise rapidly, and a large amount of gas will be generated, so that the pressure in the immersion cavity 140 will rise sharply, and any one of the above two points can be used to determine whether the battery unit 120 is in thermal runaway. When the battery unit 120 is in thermal runaway, the electrolyte therein is easy to leak into the immersion liquid, causing pollution of the immersion liquid, and if the immersion liquid still participates in the circulation at this time, the immersion liquid in the entire energy storage system will be contaminated, which will seriously affect the normal operation of the energy storage system. In this application, through the setting of the fifth valve body 1631, intermittent discharge of the overflow immersion liquid is realized, and when the liquid level in the overflow cavity 150 reaches the first preset height H1, the fifth valve body 1631 is started to discharge liquid. The first preset height H1 is a height lower than the lower end surface of the dry part 180 by a certain distance, and optionally, the difference between the height of the lower end surface of the dry part 180 and the first preset height H1 is 10-20 mm. This setting can store a certain amount of immersion liquid in the overflow cavity 150, so that the immersion liquid does not flow into the circulation system at the first time, thereby preventing the immersion liquid mixed with the electrolyte from flowing into the circulation system when the electrolyte leaks due to thermal runaway, and ensuring the purity of the immersion liquid in the energy storage system. In addition, when the temperature of the battery unit 120 in thermal runaway decreases to a certain extent, and the air pressure in the box body 110 also decreases to a certain extent, it indicates that the thermal runaway of the battery unit 120 has been effectively alleviated, and at this time, the immersion liquid in the immersion tank assembly 100 can be completely discharged to facilitate the subsequent processing of the operator receiving the alarm.

[0073] As one of the optional embodiments, the preset temperature rise rate v2 is between 1.8℃ / s and 2.2℃ / s, and preferably 2℃ / s; and the preset pressure threshold P2 is between 118KPa and 122KPa, and preferably 120KPa. Through the above preset conditions, it can be determined whether the battery unit 120 is in thermal runaway, so as to timely take appropriate measures to reduce the risk.

[0074] In one embodiment, the alarm signal includes one or a combination of sound, vision, vibration, and remote monitoring platform notification. Through the alarm signal, the operator can be timely notified to dispose the battery unit 120 in thermal runaway, thereby avoiding risk escalation.

[0075] In step S5, the first preset temperature threshold Q1 is 50-60℃, preferably 55℃. It should be understood that when thermal runaway occurs, there is a large amount of relatively low-temperature immersion liquid in the immersion cavity 140, although it is disconnected from the immersion liquid circulating in the energy storage system, but it can still prevent the battery cell 120 from catching fire and exchange heat with the battery cell 120 in thermal runaway, thereby causing its temperature to drop rapidly, and when its temperature drops below the first preset temperature threshold Q1, it indicates that the thermal runaway process has stabilized, avoiding further risks, at this time the immersion liquid in the immersion tank assembly 100 can be discharged to facilitate subsequent processing by the operator.

[0076] On this basis, the embodiment also provides an immersion energy storage device, comprising:

[0077] The immersion tank assembly 100 as described above;

[0078] A temperature adjusting device 400 connected with the immersion tank assembly 100, for adjusting the temperature of the immersion liquid circulating therein.

[0079] In the prior art, during the operation of the submerged energy storage system, the liquid level is often unstable, and in some cases, the battery unit 120 cannot be fully temperature-controlled and regulated, which can cause temperature imbalance, excessive temperature difference, and other safety problems such as thermal runaway after long-term operation, affecting the safe and stable operation of the battery unit 120. In actual operation, the liquid level is usually adjusted by controlling the flow rate of the inlet and outlet pipes to keep it within a safe operating range. However, the researchers of the present application found that the liquid level cannot be kept stable in this case. After research, it was found that as the heat exchange between the battery unit 120 and the immersion liquid progresses, the viscosity of the immersion liquid changes accordingly, resulting in different viscosities of the immersion liquid at the inlet and outlet positions of the immersion tank assembly 100. Under normal circumstances, as the temperature rises, the viscosity of the immersion liquid will decrease to some extent, resulting in a slight difference between the outlet flow rate and the inlet flow rate. As the energy storage system operates for a long time, these differences accumulate to form differences in the liquid level, affecting the operational safety of the battery unit 120. In this embodiment, the immersion chamber 140 and the overflow chamber 150 are formed in the tank body 110 by the arrangement of the partition 130. The immersion liquid in the immersion chamber 140 needs to pass over the partition 130 to enter the overflow chamber 150 and be discharged, so that the liquid level in the immersion chamber 140 is stably maintained at the same height as the partition 130, thereby achieving the stability of the liquid level in the tank body 110 with a simple structure, allowing the battery unit 120 to be in a stable temperature regulation environment and enabling it to operate safely and stably. In addition, as the temperature rises during the heat exchange process, the density of the immersion liquid also gradually decreases, and it is usually located near the upper layer of the immersion liquid. Therefore, the immersion liquid overflowing through the partition 130 is usually the relatively higher temperature part of the immersion chamber 140, which helps to retain the lower temperature immersion liquid in the immersion chamber 140, improving its temperature regulation capability.

[0080] As one of the optional embodiments, as Figure 1 、 Figure 2As shown, a liquid input portion 160 is arranged at the bottom of the box body 110, the liquid input portion 160 comprises a liquid inlet cavity 164, the liquid inlet cavity 164 is arranged corresponding to the immersion cavity 140, a plurality of liquid inlet holes 111 are arranged between the liquid inlet cavity 164 and the immersion cavity 140, one end of a liquid input pipeline 161 is connected with the liquid inlet cavity 164, and the other end is connected with a liquid outlet 442 of a temperature adjusting device 400, the liquid input pipeline 161 is arranged at a side away from the partition plate 130, and is used for injecting the immersion liquid into the liquid inlet cavity 164. It should be understood that more than one battery unit 120 is arranged in the immersion cavity 140, and the immersion liquid is directly injected into the immersion cavity 140, which is easy to interfere with the battery unit 120 and affect the flow state of the immersion liquid in the immersion cavity 140, the arrangement of the liquid input portion 160 can avoid directly injecting the immersion liquid into the immersion cavity 140, help to adjust the flow state of the immersion liquid, ensure the heat exchange efficiency, and the arrangement of the liquid input pipeline 161 at the side away from the partition plate 130 helps to improve the flow path of the immersion liquid in the box body 110 and improve the heat exchange efficiency.

[0081] As one of the preferred embodiments, more than two battery units 120 are arranged in the box body 110, a certain gap is kept between adjacent battery units 120, between the battery unit 120 and the wall surface of the box body 110, and between the battery unit 120 and the partition plate 130, and a plurality of liquid inlet holes 111 are arranged in the gap. Figure 3 As shown, four battery units 120 are arranged in the immersion cavity 140, a certain gap is kept between the leftmost battery unit 120 and the left wall, a certain gap is kept between the rightmost battery unit 120 and the partition plate 130, and a certain gap is kept between adjacent battery units 120, and the liquid inlet holes 111 are arranged in five columns in the five gaps.

[0082] As another preferred embodiment, as shown in the figure, Figure 4 As shown, the bottom surface of the liquid inlet cavity 164 gradually rises from the side close to the liquid input pipeline 161 to the side close to the partition plate 130, forming a liquid inlet slope 165. It should be understood that if the bottom surface of the liquid inlet cavity 164 is a plane, the liquid pressure on the side close to the partition plate 130 gradually decreases with the flow of the immersion liquid into the box body 110, which cannot stably supply liquid to the box body 110, and the immersion liquid in the box body 110 may also flow backward. Through the above arrangement, the liquid pressure of the immersion liquid in the liquid inlet cavity 164 from the side close to the liquid input pipeline 161 to the side close to the partition plate 130 is kept stable, so that the liquid supply is kept stable.

[0083] As one of the optional embodiments, the lower end of the partition plate 130 can be arranged on the bottom plate of the tank 110, or can extend downward into the liquid inlet 160. In this case, the bottom plate of the tank 110 is removed from the overflow chamber 150, and the bottom plate of the liquid inlet 160 serves as the bottom plate of the overflow chamber 150. This arrangement keeps the outer dimensions of the lower side of the immersion tank assembly 100 consistent, forms a regular shape, facilitates installation and transportation, and appropriately increases the capacity of the overflow chamber 150.

[0084] As another preferred embodiment, as shown in Figure 4 the inner wall of the immersion chamber 140 and the side of the partition plate 130 close to the liquid inlet 164 are provided with a plurality of turbulence plates 170 extending toward the battery unit 120. During operation, a temperature boundary layer is formed at the position where the surface of the battery unit 120 contacts the immersion liquid. This temperature boundary layer forms a temperature gradient in a very thin area close to the surface of the battery unit 120, which greatly negatively affects the convective heat transfer during the flow of the immersion liquid and seriously affects the heat exchange effect between the immersion liquid and the battery unit 120. The turbulence plates 170 are used to change the flow state of the immersion liquid in the immersion chamber 140, so that a certain turbulence is formed during the flow, which can destroy the temperature boundary layer on the surface of the battery unit 120, thereby significantly improving the heat exchange efficiency and the temperature control effect. Preferably, turbulence vertical plates can also be arranged between adjacent battery units 120, and turbulence plates 170 extending toward the two battery units 120 are arranged on the turbulence vertical plates to further improve the turbulence state of the immersion liquid. It should be noted that the inner wall of the immersion chamber 140 can be the front wall, rear wall, left wall, and right wall (the wall surface of the partition plate 130 facing the battery unit 120) as shown in Figure 3 、 Figure 4 , which will not be described again.

[0085] As one of the embodiments, as shown in Figure 4 the lengths of the plurality of turbulence plates 170 extending toward the battery unit 120 are inconsistent. This arrangement can further improve the degree of disorder of the turbulence of the immersion liquid, thereby inhibiting the formation of the temperature boundary layer and improving the heat exchange efficiency.

[0086] Optionally, as shown in Figure 4As shown, the spoiler 170 includes long spoilers and short spoilers, the length of the long spoilers extending to the direction of the battery unit 120 (hereinafter referred to as the extension length) is greater than the length of the short spoilers extending to the direction of the battery unit 120, and the long spoilers and the short spoilers on the same wall surface are arranged at intervals. Through the above arrangement, the adjacent two spoilers 170 have different effects on the spoiler of the immersion liquid, so as to form a spoiler pattern, facilitate the destruction of the temperature boundary layer, and improve the heat exchange efficiency. It should be noted that the end of the spoiler 170 away from the wall surface can be semicircular, triangular, or beveled, and the shape of the end of the adjacent spoiler 170 away from the wall surface can be the same or different.

[0087] Specifically, the extension length of the long spoiler is denoted as h1, the extension length of the short spoiler is denoted as h2, and the distance between the wall surface where the spoiler 170 is located and the battery unit 120 is denoted as H, then 2h1

[0088] As one of the optional embodiments, the overflow pipeline 163 is connected with the liquid inlet 441 of the temperature adjusting device 400. Through the above arrangement, the immersion liquid overflowing through the partition plate 130 flows into the temperature adjusting device 400 for temperature adjustment, and the adjusted immersion liquid is transported into the liquid input part 160 through the liquid outlet 442, the liquid input pipeline 161, and then supplied into the tank 110, to complete the circulation of the immersion liquid in normal operation.

[0089] In another optional embodiment, the liquid drain pipe 162 is disposed on the liquid inlet 160, and is located on the side away from the partition 130. The liquid drain pipe 162 is used to drain the immersion liquid in the liquid inlet 160 and the housing 110 when necessary. In the event of thermal runaway due to electrolyte leakage in the battery cell 120, or when maintenance or repair of the battery cell 120 or the housing 110 is required, the immersion liquid in the liquid inlet 160 and the housing 110 must be drained first. Since the overflow chamber 150 is not connected to the bottom of the immersion chamber 140, the immersion liquid in the housing 110 and the liquid inlet 160 cannot be drained. The liquid drain pipe 162, located on the side away from the partition 130, and with the aid of the inlet slope 165, can quickly drain the immersion liquid in the housing 110 and the liquid inlet 160, facilitating the replacement and maintenance of components in the immersion tank assembly 100.

[0090] Preferably, a removable drying section 180 is provided within the overflow cavity 150, and there is a certain distance between the end of the drying section 180 and the separator 130. The distance between the drying section 180 and the separator 130 is greater than half the width of the overflow cavity 150, where the width of the overflow cavity 150 refers to the distance between the wall surface of the separator 130 away from the battery cell 120 and... Figure 4 The distance between the inner right side of the middle housing 110 is avoided. With the above arrangement, since the overflowing immersion liquid flows along the wall of the separator 130 away from the battery cell 120, it will not contact the drying section 180, nor will it affect the performance of the immersion liquid. The drying section 180 includes a desiccant, such as silica gel. The drying section 180 can be a porous container; specific details can be found in existing technology and are not limited here. Through the above arrangement, the overflowing immersion liquid has a large surface area, facilitating the absorption of moisture by the drying section 180, thereby ensuring the insulation effect of the immersion liquid and extending its service life. It should be noted that the drying section 180 is sealed to the housing 110, facilitating the replacement of the desiccant. Specific sealing assembly structures can be found in existing technology and are not limited here.

[0091] Specifically, such as Figure 12 As shown, one end of the liquid output pipeline 166 is connected to the liquid drain pipeline 162 and the overflow pipeline 163, respectively, and the other end is connected to the temperature regulating device 400. With this configuration, when maintenance or repair is required, the immersion liquid in the immersion tank assembly 100 can be completely drained, and the drained immersion liquid can be stored in other storage containers or used for temperature regulation of other immersion tank assemblies 100. It should be understood that when the immersion liquid in the immersion tank assembly 100 undergoing maintenance or repair is stored in other containers, a corresponding storage container and a valve controlling its on / off state are also connected to the liquid output pipeline 166, which will not be elaborated further here.

[0092] Optionally, a pump body 600 is arranged on at least one of the liquid input pipeline 161 and the liquid output pipeline 166, and is used to drive circulation of the immersion liquid. A pump body 600 (not shown in the figure) is arranged on the waste liquid pipeline 510, and is used to discharge the immersion liquid in the immersion tank assembly 100. By arranging the pump body 600, the circulation or discharge speed of the immersion liquid can be accelerated.

[0093] In the embodiment, the temperature adjusting device 400 can be a conventional water cooling unit or other heat exchange device, or can be a structure provided as follows:

[0094] As shown in Figures 6-11 The temperature adjusting device 400 includes a heat exchange structure 440, a temperature adjusting tank 410, an external magnet 420, an internal magnet 430, a first magnetic receiving body 460, and a second magnetic receiving body 470. The heat exchange structure 440 is used to contain the immersion liquid for circulation, and to perform heat exchange and temperature adjustment of the immersion liquid inside the heat exchange structure 440. The heat exchange structure 440 is arranged in a cylindrical shape. The temperature adjusting tank 410 is arranged on the outer periphery of the heat exchange structure 440, and surrounds the heat exchange structure 440 at the center position. The external magnet 420 is arranged on the outer side of the upper and lower ends of the temperature adjusting tank 410, and is arranged close to the outer periphery of the temperature adjusting tank 410. The internal magnet 430 is arranged on the outer side of the upper and lower ends of the temperature adjusting tank 410, and is arranged close to the outer periphery of the heat exchange structure 440. The first magnetic receiving body 460 and the second magnetic receiving body 470 are arranged inside the temperature adjusting tank 410. The first magnetic receiving body 460 and the second magnetic receiving body 470 can alternately move between the two positions of abutting the outer peripheral wall of the heat exchange structure 440 and abutting the inner side wall of the temperature adjusting tank 410. The external magnet 420 or the internal magnet 430 can apply a magnetic field to the first magnetic receiving body 460 and the second magnetic receiving body 470 in an intermittent manner.

[0095] The first magnetic body 460 and the second magnetic body 470 can alternately move between the position of abutting the outer circumferential wall of the heat exchange structure 440 and the position of abutting the inner lateral wall of the temperature adjusting box 410. When the first magnetic body 460 moves to the position of abutting the outer circumferential wall of the heat exchange structure 440, the second magnetic body 470 is located at the position of abutting the inner lateral wall of the temperature adjusting box 410. When the second magnetic body 470 moves to the position of abutting the outer circumferential wall of the heat exchange structure 440, the first magnetic body 460 is located at the position of abutting the inner lateral wall of the temperature adjusting box 410. In the embodiment, the external magnetic body 420 and the internal magnetic body 430 are electromagnets, which can generate a magnetic field in the state of being powered on and eliminate the magnetic field in the state of being powered off. The first magnetic body 460 and the second magnetic body 470 are magnetic heat materials, which are magnetized and heated when subjected to the magnetic field and are heated when demagnetized. The temperature adjustment of the immersion liquid can be realized by using the above characteristics. For example, when the immersion liquid needs to be cooled, the internal magnetic body 430 does not work, and the external magnetic body 420 intermittently applies a magnetic field to the first magnetic body 460 and the second magnetic body 470. Specifically, as shown in FIG. 4, the external magnetic body 420 applies a magnetic field to the first magnetic body 460 and the second magnetic body 470 in the state of being powered on, and the first magnetic body 460 and the second magnetic body 470 are magnetized and heated. When the external magnetic body 420 is powered off, the first magnetic body 460 and the second magnetic body 470 are demagnetized and heated. The temperature adjustment of the immersion liquid can be realized by using the above characteristics. For example, when the immersion liquid needs to be cooled, the internal magnetic body 430 does not work, and the external magnetic body 420 intermittently applies a magnetic field to the first magnetic body 460 and the second magnetic body 470. Specifically, as shown in FIG. 4, the external magnetic body 420 applies a magnetic field to the first magnetic body 460 and the second magnetic body 470 in the state of being powered on, and the first magnetic body 460 and the second magnetic body 470 are magnetized and heated. When the external magnetic body 420 is powered off, the first magnetic body 460 and the second magnetic body 470 are demagnetized and heated. Figure 10 、 Figure 11As shown, when the first magnetic body 460 moves to the position abutting the inner side wall of the temperature control box 410, at this time the second magnetic body 470 is located at the position abutting the outer peripheral wall of the heat exchange structure 440, the external magnetic body 420 applies a magnetic field to the first magnetic body 460, the first magnetic body 460 is magnetically heated to release heat to the inner side wall of the temperature control box 410, and the heat is dissipated through the inner side wall. After the magnetic field is applied, the second magnetic body 470 moves to the inner side wall of the temperature control box 410, and the first magnetic body 460 moves to the heat exchange structure 440 (the movement between the two is based on the principle of not interfering with each other). When the second magnetic body 470 is located at the position abutting the inner side wall of the temperature control box 410, the external magnetic body 420 applies a magnetic field to the second magnetic body 470, the second magnetic body 470 is magnetically heated to release heat to the inner side wall of the temperature control box 410, and the heat is dissipated through the inner side wall. At this time, the first magnetic body 460 is located at the position abutting the outer peripheral wall of the heat exchange structure 440, and the first magnetic body 460 becomes cold due to the disappearance of the magnetic field, absorbs heat from the immersed liquid through the heat exchange structure 440, thereby realizing a primary refrigeration cycle. When heating is required, the external magnetic body 420 does not work, and the internal magnetic body 430 intermittently applies a magnetic field to the first magnetic body 460 and the second magnetic body 470. The specific operation mode and the movement mode of the related components can be reasonably inferred through the refrigeration cycle, thereby completing the heating cycle of the immersed liquid. Details are not described herein. Through the above arrangement, rapid refrigeration or heating of the immersed liquid can be realized, the heat exchange efficiency is high, it is more energy-saving, safe, environmentally friendly, and easy to miniaturize. Preferably, a heat sink corresponding to the first magnetic body 460 and the second magnetic body 470 is arranged on the inner side wall of the temperature control box 410 (not shown in the figure), and the heat sink is connected to a heat dissipation structure outside the temperature control box 410. The heat dissipation structure can be a conventional air cooling, water cooling or air cooling structure, which is not limited herein. This arrangement can significantly improve the heat dissipation effect, thereby realizing smooth heat dissipation. Alternatively, the magnetic heat material can be La(FeSi)13 type magnetic heat material, or other known magnetic heat material, which is not limited herein.

[0096] Further, the first magnetic body 460 and the second magnetic body 470 each include an equal number of sub-magnetic bodies, and the sub-magnetic bodies in the first magnetic body 460 and the second magnetic body 470 are arranged at intervals in the outer periphery of the heat exchange structure 440. When the first magnetic body 460 or the second magnetic body 470 abuts the outer peripheral wall of the heat exchange structure 440, the sub-magnetic bodies therein can abut the outer peripheral wall of the heat exchange structure 440. Through the above arrangement, the overall heat exchange of the outer peripheral wall of the heat exchange structure 440 can be realized, and the heat exchange efficiency can be significantly improved. Moreover, since the first magnetic body 460 and the second magnetic body 470 alternately abut the outer peripheral wall of the heat exchange structure 440, the interval time between movement and magnetic field application and demagnetization can be reduced, thereby improving the heat exchange efficiency.

[0097] In the present embodiment, as shown in Figure 10 ,Figure 11 As shown, inside the temperature control box 410 is provided with a sliding rail 480 and a driving structure (not shown in the figure) corresponding to each sub-magnet, the sub-magnet is in one-to-one sliding connection with the sliding rail 480, and is used to move along the sliding rail 480 under the driving of the driving structure. It should be noted that the driving structure can be a conventional structure such as a motor-driven screw structure, a belt structure, etc. in the prior art, which will not be limited here.

[0098] As one of the preferred embodiments, a plurality of fins 450 are provided on the outer peripheral wall of the temperature control box 410, which are used to improve the heat dissipation effect of the temperature control box 410.

[0099] Specifically, the heat exchange structure 440 includes a liquid inlet 441, a liquid outlet 442 and a heat exchange cavity 443, the liquid inlet 441 and the liquid outlet 442 are connected with the heat exchange cavity 443 respectively, the liquid inlet 441 is connected with the liquid output pipeline 166, and the liquid outlet 442 is connected with the liquid input pipeline 161. Through the above setting, the immersion liquid passing through the immersion tank assembly 100 enters the heat exchange cavity 443 through the liquid inlet 441, is temperature-regulated in the heat exchange cavity 443, and then flows into the immersion tank assembly 100 through the liquid outlet 442, realizing the circulation of the immersion liquid and significantly improving the temperature control effect of the battery unit 120. Preferably, a stirring device is further provided in the heat exchange cavity 443, which is used to stir the immersion liquid in the heat exchange cavity 443 to destroy the temperature boundary layer between the heat exchange cavity 443 and the immersion liquid, thereby improving the heat exchange effect. The stirring device can refer to the structure of the liquid stirring device in the existing technology, which will not be limited here.

[0100] On this basis, the embodiment further provides a temperature control method of the energy storage system, which includes the following steps:

[0101] Step S1: obtaining the temperature of the battery unit, judging the required temperature control method, if the temperature needs to be raised, executing step S2, if the temperature needs to be lowered, executing step S5;

[0102] Step S2: starting the temperature regulating device to heat the immersion liquid, when the temperature rises to the first target temperature T1, the liquid input pipeline is connected to supply liquid to the immersion tank assembly, and then step S3 is executed:

[0103] Step S3: monitoring the temperature of the battery unit, when the temperature reaches the second target temperature T2, the energy storage system starts to operate, the temperature regulating device stops heating, and the immersion liquid stops being delivered, and step S4 is executed;

[0104] Step S4: but when the temperature of the battery unit exceeds the third target temperature T3, step S5 is executed;

[0105] Step S5: start the temperature adjusting device to cool the immersion liquid, and turn on the liquid input pipeline to supply liquid to the immersion tank assembly. When the battery cell temperature is lower than the fourth target temperature T4, the energy storage system starts to operate and executes step S6.

[0106] Step S6: stabilize the operation of the temperature adjusting device to control the immersion liquid supply temperature within the first preset temperature range T5.

[0107] Step S2 includes:

[0108] Step S21: start the temperature adjusting device and move the first magnet to the position close to the outer peripheral wall of the heat exchange structure.

[0109] Step S22: energize the inner magnet to magnetize the first magnet. The magnetized first magnet releases heat and exchanges heat with the immersion liquid in the heat exchange structure to warm it up.

[0110] Step S23: after the first duration t1 of magnetizing the first magnet, the first magnet and the second magnet switch positions. The inner magnet magnetizes the second magnet. The magnetized second magnet releases heat and exchanges heat with the immersion liquid in the heat exchange structure to warm it up.

[0111] Step S24: after the first duration t1 of magnetizing the second magnet, the second magnet and the first magnet switch positions. The inner magnet magnetizes the first magnet. The magnetized first magnet releases heat and exchanges heat with the immersion liquid in the heat exchange structure to warm it up.

[0112] Step S25: repeat steps S23 and S24 until the immersion liquid is warmed up to the first target temperature T1, and execute step S26.

[0113] Step S26: turn on the liquid input pipeline to supply liquid to the immersion tank assembly.

[0114] It should be noted that when the magnetocaloric material is magnetized, the magnetic moment of the material is ordered along the external magnetic field, resulting in a decrease in magnetic entropy and heat release of the material; while when the magnetization is removed, the magnetic moment changes from order to disorder, the magnetic entropy increases, and the material absorbs heat, therefore, the magnetization heat absorption and demagnetization heat release process of the magnetocaloric material is carried out in stages, and the magnetic moment needs to be changed by demagnetization after a certain time of magnetization, therefore, the first time length t1 is a preset time data, which is affected by multiple factors such as the heat conduction rate of different materials, the size of the component, the area of the fitted surface, and the time of magnetic moment ordering, and is not limited here. Taking individual numbers as an example, t1 can be 3 minutes. The first target temperature T1 is a preset value, and the value range is 5-10°C, preferably 8°C. It should be understood that the energy storage system such as the energy storage container can be set in a relatively harsh environment, and therefore the setting environment may appear extremely cold weather, such as a temperature below-30°C or even-40°C. In this case, the battery unit 120 cannot operate normally and needs to be preheated using the immersion liquid before starting to operate, so that it reaches a temperature range that can be relatively normally operated, which can effectively ensure the safety and stability of the battery unit 120.

[0115] In step S3, the value range of T2 is 10-20°C. Preferably, it is 15°C. Within this temperature range, the battery unit 120 can operate normally, and during operation, the battery unit 120 will continue to heat, and the temperature of the immersion liquid will also gradually increase, so that the battery unit 120 can be maintained within the normal operating temperature range.

[0116] In step S4, the value range of T3 is 35-40°C. Preferably, it is 35°C. At this temperature, the battery unit 120 can still operate normally, but as the running time increases, the non-circulating immersion liquid cannot maintain the temperature stability of the battery unit 120, and at this time, the temperature regulating device 400 needs to be used to cool the immersion liquid in order to maintain the temperature stability of the battery unit 120.

[0117] Step S5 includes:

[0118] Step S51: Start the temperature regulating device, and move the first magnet to a position where it is fitted to the inner side wall of the temperature regulating box;

[0119] Step S52: The external magnet is energized and magnetized, the first magnet is magnetized, and the magnetized first magnet is heated and cooled through the side wall of the temperature regulating box;

[0120] Step S53: After the first magnet is magnetized for a first time length t1, the first magnet and the second magnet switch positions, the external magnet magnetizes the second magnet, and the magnetized second magnet is heated and cooled through the side wall of the temperature regulating box; at this time, the first magnet is fitted to the outer peripheral wall of the heat exchange structure, and absorbs heat from the immersion liquid inside the heat exchange structure to cool it down;

[0121] Step S54: After the second magnet is magnetized for the first time duration t1, the second magnet and the first magnet switch positions, the external magnet magnetizes the first magnet, and the magnetized first magnet releases heat, which is dissipated through the sidewall of the temperature adjusting device. At this time, the second magnet is attached to the outer circumferential wall of the heat exchange structure and absorbs heat from the immersion liquid inside the heat exchange structure to reduce the temperature.

[0122] Step S55: Connect the liquid input pipeline to supply liquid to the immersion tank assembly.

[0123] Step S56: When the battery cell temperature is lower than the fourth target temperature T4, the energy storage system starts to operate.

[0124] After the temperature of the immersion liquid is reduced by the temperature adjusting device 400, it can be directly supplied to the immersion tank assembly 100, thereby immediately reducing the operating temperature of the battery cell 120. In nature, under normal circumstances, the temperature will not exceed the normal operating temperature range of the battery cell 120. When an extreme situation occurs, which exceeds the normal operating range, first start the temperature adjusting device 400 to cool, and at the same time, the immersion liquid is transported to the immersion tank assembly 100. When the temperature of the battery cell 120 is reduced to an appropriate temperature, start to operate. This ensures the safety of the operation of the battery cell 120, and also ensures that it has the best operating performance and service life. The fourth target temperature T4 is a preset value, and its value range is 35℃-45℃, preferably 40℃. This setting can avoid the operation of the battery cell 120 at high temperature, so that it is in a better operating temperature range.

[0125] In step S6, the first preset temperature range T5 is in the range of 20℃-30℃. Preferably, it is 20℃-25℃. The above temperature range can be achieved by the stage operation of the temperature adjusting device 400, similar to the variable frequency operation of an air conditioner, which will not be described here. Through the above setting, the operating range of the battery cell can be controlled in the range of 22℃-35℃, so that it is in the best working temperature range, which ensures its use performance and service life.

[0126] In addition, the embodiment also provides a thermal runaway control device for executing the temperature control method as described above, which at least comprises:

[0127] A pressure detection unit for detecting the air pressure in each immersion tank assembly;

[0128] A temperature detection unit for detecting the temperature of each battery cell;

[0129] A judgment unit for judging whether the temperature rise rate and the air pressure meet the judgment condition of thermal runaway;

[0130] a control unit configured to control the execution of the corresponding thermal runaway control method.

[0131] In the current immersion energy storage system, in addition to the risk of thermal runaway of the battery unit 120, there is also the risk of immersion liquid leakage, which is easy to cause system failure, environmental pollution and health hazards, ecological problems, and fire safety, etc., which needs to be reduced through strict management and technical measures.

[0132] In order to effectively respond to the risk of immersion liquid leakage in the immersion energy storage system, based on the above structure, the embodiment also provides an immersion energy storage system immersion liquid leakage detection method, which is used for the immersion tank assembly 100 as described above, comprising the following steps:

[0133] Step 1: During the operation of the energy storage system, the immersion tank assembly is operated in a rotation mode, that is, at least one immersion tank assembly in all immersion tank assemblies contained therein does not participate in operation during the operation of the energy storage system.

[0134] Step 2: Close the liquid input pipeline of the immersion tank assembly in the rotation state;

[0135] Step 3: After a first predetermined time, detect the liquid level of the immersion liquid in the immersion cavity, and record the actual liquid level of the immersion cavity at this time as a first liquid level L1;

[0136] Step 4: Compare the first liquid level L1 with the height D of the partition plate, when L1≥D, execute step 5; when L1

[0137] Step 5: Judge that there is no immersion liquid leakage in the current immersion cavity, open the liquid input pipeline corresponding to the immersion tank assembly, when the rotation ends, the immersion tank assembly normally participates in the operation of the energy storage system, and the immersion tank assembly is not detected for liquid leakage for a period of time.

[0138] Step 6: Judge that there is immersion liquid leakage in the current immersion cavity, maintain the rotation of the immersion tank assembly and the closed state of the liquid input pipeline, isolate the current immersion tank assembly from the energy storage system, and issue a liquid leakage alarm signal.

[0139] In the embodiment, the liquid level in all the immersion tank assemblies 100 is in a stable state by the arrangement of the partition plate 130, and thus the height of the partition plate 130 naturally becomes the corresponding target liquid level when leakage detection is needed. If the liquid level after stopping for a period of time is lower than the liquid level of the partition plate 130, it indicates that there is a leakage in the immersion cavity 140, and corresponding processing operation is needed. In this case, the initial liquid level in the immersion cavity 140 does not need to be detected, and all the immersion liquids in the immersion cavities 140 are at the same liquid level, which significantly reduces the number of liquid level signals detected in the energy storage system and the number of data processed, so that the leakage of the immersion tank assembly 100 can be simply and conveniently detected, so that the leakage can be processed more timely and accurately. It should be noted that when the fifth valve body 1631 is not arranged in the overflow pipeline or the fifth valve body 1631 is in the normally open state, the immersion liquid cannot be accumulated therein, and thus the leakage thereof has little effect on the immersion tank assembly 100, and the leakage thereof can not be monitored, which significantly reduces the workload of leakage detection. Through the above arrangement, the leakage can be detected without affecting the normal operation of the energy storage system, so that the operator can timely perform corresponding processing, and the risk of the energy storage system due to leakage is reduced. At the same time, the rotation also helps to balance the state of charge of the battery units 120 in the energy storage system, and reduces the risk of overcharging or overdischarging of the battery units 120. The first preset time is 20s-40s, and is preferably 30s.

[0140] Step 1 comprises:

[0141] Step 11: judging the current running state of the energy storage system, executing step 12 in the charging state; executing step 13 in the discharging state;

[0142] Step 12: comparing the SOC values of the battery units in each immersion tank assembly, and performing rotation according to the order from high to low of the SOC values.

[0143] Step 13: comparing the SOC values of the battery units in each immersion tank assembly, and performing rotation according to the order from low to high of the SOC values.

[0144] Through the above setting, when charging, the battery unit 120 in the immersion tank assembly 100 with the highest SOC value is first rested, so that other battery units 120 can quickly shorten the power gap with the battery unit 120 with the highest SOC value, thereby helping to achieve the balance of the battery unit 120 charge during charging, avoiding overcharging, and reducing the risk of thermal runaway; when discharging, the battery unit 120 in the immersion tank assembly 100 with the lowest SOC is first rested, thereby helping to achieve the power balance of the battery unit 120 during discharging, avoiding over-discharging, and ensuring the service life of the battery unit 120. It should be noted that the SOC value of the battery unit 120 in the immersion tank assembly 100 described in this embodiment is the mean or median value of the SOC of the battery unit 120 that can normally operate, and the SOC difference of the battery unit 120 in the same immersion tank assembly 100 can be controlled by other existing balancing means, which will not be limited here. The detection of the SOC value can refer to the existing technology in the energy storage system, which will not be repeated here. Through the above control method, the operation of the energy storage system and the detection of the liquid leakage can be performed synchronously, and the balance control of the state of charge of the battery unit 120 in the immersion tank assembly 100 can also be achieved.

[0145] Specifically, step 12 further comprises:

[0146] Step 121: comparing the SOC of the battery unit in the immersion tank assembly whose rest is over and no liquid leakage is detected with the current SOC of the battery unit in other immersion tank assemblies, and continuing to rest in order from high to low according to the SOC for charging.

[0147] Step 13 further comprises:

[0148] Step 131: comparing the SOC value of the battery unit in the immersion tank assembly whose rest is over and no liquid leakage is detected with the current SOC of the battery unit in other immersion tank assemblies, and continuing to rest in order from low to high according to the SOC for discharging.

[0149] Through the above setting, while detecting whether there is liquid leakage, the difference in the state of charge of the battery unit 120 between different immersion tank assemblies 100 can be significantly reduced, thereby reducing the risk of thermal runaway or damage to the service life of the battery unit 120 caused by overcharging or over-discharging.

[0150] As one of the optional embodiments, in step 1, the rest time of each immersion tank assembly is obtained according to formula (1):

[0151]

[0152] Wherein, Ti is the rest time of the current immersion tank assembly, Tb is the basic rest time, Tc is the rest time coefficient, ΔSOC is the difference between the SOC value of the battery cell in the current immersion tank assembly and the maximum or minimum SOC value in the energy storage system, specifically, when charging, ΔSOC is the difference between the SOC value of the battery cell in the current immersion tank assembly and the minimum SOC value in the energy storage system, when discharging, ΔSOC is the difference between the maximum SOC value in the energy storage system and the SOC value of the battery cell in the current immersion tank assembly, R is the charge / discharge rate, and Tb and Tc are preset values.

[0153] Through the above setting, the rest time of the immersion tank assembly 100 with different SOC values is different, and the rest time of the immersion tank assembly 100 with a larger SOC value is longer when charging, and the rest time of the immersion tank assembly 100 with a smaller SOC value is longer when discharging, thereby improving the problem of imbalance of the state of charge of the battery cell 120 in the immersion tank assembly 100 to some extent. It should be understood that the fundamental purpose of the embodiment is to detect whether there is liquid leakage in the energy storage system, and in this case, if the rest time is too long, it will not be possible to effectively detect all the immersion tank assemblies 100, and in this case, by pre-setting Tb and Tc, the rest time of each immersion tank assembly 100 can be effectively controlled, thereby ensuring the smooth progress of the liquid leakage detection. Wherein Tb and Tc can be equal or not equal, taking one of the discharge states as an example, Tb and Tc are preset to 60 seconds, ΔSOC is 0.2, and the discharge rate is 0.5C. According to the calculation, the rest time of the immersion tank assembly 100 is 90 seconds. Through the above setting, the rest time of the immersion tank assembly 100 is limited to between 60 seconds and 120 seconds, ensuring the smooth progress of the immersion liquid leakage detection, and at the same time, the state of charge of the battery cell 120 in the immersion tank assembly 100 is balanced to some extent. Specifically, the operator can pre-set Tb and Tc according to the type of battery cell 120, the number of immersion tank assemblies 100 and other related information, which is not limited herein. It should be understood that R represents the discharge rate in the discharge state and the charge rate in the charge state.

[0154] Optionally, for the immersion tank assembly determined to have no liquid leakage, Tb in formula (1) is recorded as 0. This setting can reduce the rest time of the immersion tank assembly 100 determined to have no liquid leakage, thereby speeding up the detection efficiency of the liquid leakage of the energy storage system.

[0155] Further, a second tank 700 is sealingly arranged outside the tank body 110, and the immersion tank assembly 100 is partially arranged in the second tank 700. A liquid receiving disc 710 is arranged at the inner bottom end of the second tank 700, which is used to collect the leaked liquid when the immersion liquid leaks and discharge it to the waste liquid tank 500.

[0156] In the embodiment, the second tank 700 is sealingly arranged with the tank 110, so that even if the immersion liquid leaks, it will directly flow into the waste liquid tank 500 and will not leak to the outside environment, thereby significantly improving the use safety of the energy storage system. It should be understood that, in order to facilitate the assembly of the aforementioned pressure relief assembly 200, the connection position of the top cover of the second tank 700 with the tank 110 is located on the lower side of the pressure relief assembly 200, in which case the pressure relief plate 190 will also be located on the upper side of the second tank 700. In addition, the arrangement of the partition plate 130 facilitates the stabilization of the liquid level, so that the reference liquid level during the detection of liquid leakage remains consistent, thereby making it easier to distinguish that the immersion tank assembly 100 has leaked.

[0157] As one of the optional embodiments, the connection position of the top cover of the second tank 700 with the tank 110 is higher than the top end of the partition plate 130. It should be understood that, due to the arrangement of the partition plate 130, the liquid level of the immersion liquid in the immersion chamber 140 will not exceed the top end of the partition plate 130 during normal operation, so that even if the immersion liquid leaks, the leakage point will not be higher than the top end of the partition plate 130. Therefore, through the above arrangement, the second tank 700 can completely cover all possible liquid leakage points, and the leaked immersion liquid is transferred to the waste liquid tank 500 through the liquid receiving disc 710, thereby completing the closed transfer of the leaked immersion liquid and significantly reducing the risk caused by the leakage of the immersion liquid.

[0158] As one of the optional embodiments, the liquid receiving disc 710 includes a recessed groove 711 arranged at the center position, the bottom of the immersion tank assembly 100 is embedded in the recessed groove 711, a stepped portion 712 is formed on the outer periphery of the recessed groove 711, a step is formed between the stepped portion 712 and the outer periphery of the liquid receiving disc 710 for forming a liquid receiving space, and a liquid discharge pipe 713 penetrating the outer periphery of the liquid receiving disc 710 and the second tank 700 is further arranged on the liquid receiving disc 710, and the liquid discharge pipe 713 is connected with the waste liquid tank 500. Through the above arrangement, the immersion tank assembly 100 and the second tank 700 are matched to form a pre-assembled part, and due to the arrangement of the recessed groove 711, the immersion tank assembly 100 is also limited, thereby significantly improving the stability of the assembly.

[0159] Optionally, the liquid receiving disc 710 is made of an insulating material capable of isolating the immersion liquid. For example, foam, ceramic, polyurethane, etc. The above-mentioned materials are all insulating materials, and they can effectively prevent the penetration of the immersion liquid, so that the leaked immersion liquid can be collected and discharged. In addition, since the bottom of the immersion tank assembly 100 is embedded in the recessed groove 711, the bottom of the recessed groove 711 is a sealed structure and does not have a liquid leakage space, thereby effectively preventing the risk of liquid leakage at the bottom of the immersion tank assembly 100.

[0160] On this basis, step 6 further comprises the following steps:

[0161] Step 7: detecting the liquid leakage height in the second preset time, calculating the liquid leakage rate, and then executing step 7;

[0162] Step 8: comparing the liquid leakage rate with the liquid discharge rate of the liquid discharge pipe,

[0163] When the liquid leakage rate is greater than the liquid discharge rate, the liquid discharge pipeline connected with the immersion cavity is opened to assist the liquid discharge to the waste liquid tank;

[0164] When the liquid leakage rate is less than the liquid discharge rate, the rotation of the immersion tank assembly is maintained and the liquid input pipeline is kept closed.

[0165] It should be understood that when the liquid leakage rate is high, the liquid receiving tray 710 and the second tank 700 are likely to be filled quickly, which may cause further leakage. Therefore, the immersion liquid in the immersion cavity 140 is discharged at the fastest speed to reduce the risk of immersion liquid leakage to the greatest extent. When the liquid leakage rate is low, the liquid leakage cannot fill the liquid receiving tray 710, and the second tank 700 and the components outside the second tank 700 will not be damaged. Therefore, the current state can be maintained to wait for the subsequent processing of the operator. It should be understood that the calculation of the liquid leakage rate according to the liquid leakage height belongs to the conventional calculation in the prior art, and will not be described here. The second preset time is in the range of 10s-30s, and is preferably 20s.

[0166] It should be noted that the liquid leakage alarm signal includes one or a combination of several of sound, vision, vibration, and remote monitoring platform notification. Through the liquid leakage alarm signal, the operator can be notified in time to deal with the immersion tank assembly 100 that has leaked liquid, thereby avoiding risk escalation.

[0167] The embodiment also discloses an energy storage system, which comprises the above-mentioned immersion energy storage device or adopts one or several of the temperature control method, the heat loss control method, and the immersion liquid leakage detection method. The energy storage system can be an energy storage container, an energy storage cabinet, etc., and will not be limited here.

[0168] It should be noted that the temperature detection unit, pressure detection, liquid level detection, and other corresponding data detection in the embodiment all need to be provided with corresponding detection units in the corresponding positions or spaces. The required setting methods or means are all conventional technical means in the art, and will not be described here.

[0169] The energy storage system also comprises other conventional components such as BMS, and specific reference can be made to the prior art, which will not be described here.

[0170] Although the present application has been disclosed in its currently best mode, the present application is not limited to it. In the description of the specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. The exemplary description of the above terms in the specification does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the scope of protection of the present application should be subject to the scope defined by the claims.

Claims

1. An energy storage system, characterized by, The energy storage system is an immersed energy storage system, comprising: an immersed tank assembly (100) comprising a tank body (110) and a battery unit (120), the battery unit (120) being arranged in the tank body (110) and immersed in a circulating flow of an immersion liquid arranged in the tank body (110); a pressure relief assembly (200) arranged on the upper side of the tank body (110) and sealingly connected with the tank body (110), a pressure relief channel (210) being formed between the pressure relief assembly (200) and the top of the tank body (110), at least one end of the pressure relief channel (210) being connected with a shell (300) of the energy storage system; the shell (300) being provided with a ventilation part (310) at a position corresponding to the pressure relief assembly (200); wherein a pressure relief plate (190) is arranged at the upper corner of the tank body (110) away from the baffle (130), the pressure relief plate (190) being rotatably connected with the top cover or the side wall of the tank body (110), the pressure relief plate (190) being capable of opening to discharge the gas in the tank body (110) and also capable of closing to seal the tank body (110); a baffle (130) is arranged in the tank body (110), the baffle (130) being used to separate the internal cavity of the tank body (110) into an immersion cavity (140) and an overflow cavity (150), the top end of the baffle (130) being spaced apart from the inner wall of the top plate of the tank body (110) so that the immersion cavity (140) and the overflow cavity (150) are communicated at the upper part of the baffle (130), the immersion cavity (140) is connected with a liquid input pipeline (161) for inputting the immersion liquid into the immersion cavity (140), the immersion cavity (140) is further connected with a liquid emptying pipeline (162) for discharging the immersion liquid in the immersion cavity (140), the overflow cavity (150) is connected with an overflow pipeline (163), a fifth valve body (1631) is arranged on the overflow pipeline (163), the fifth valve body (1631) being used to intermittently discharge the immersion liquid in the overflow cavity (150), the overflow pipeline (163) is connected with a liquid output pipeline (166) for the circulating flow of the immersion liquid, the liquid output pipeline (166) is further connected with a waste liquid pipe (510), the waste liquid pipe (510) is connected with a waste liquid tank (500), a fourth valve body (520) is arranged on the waste liquid pipe (510), the fourth valve body (520) being used to control the on-off of the waste liquid pipe (510); when the battery unit (120) is in thermal runaway, the liquid input pipeline (161), the liquid emptying pipeline (162), the overflow pipeline (163), the liquid output pipeline (166), the fourth valve body (520) and the waste liquid pipe (510) are used to prevent the immersion liquid mixed with electrolyte from entering the circulating system, and the pressure relief channel (210) and the pressure relief plate (190) are used to cooperate to discharge the gas discharged in thermal runaway.

2. The energy storage system of claim 1, wherein, The included angle between the pressure relief plate (190) and the side wall of the box body (110) is α, and α is 20°-40°.

3. The energy storage system of claim 1, wherein, The anti-toxic structure (230) is arranged at the position close to the shell (300) of the pressure relief channel (210), and is used for absorbing toxic gas released when the battery unit (120) is in thermal runaway.

4. The energy storage system of claim 3, wherein, An inclined waterproof plate (220) is arranged on the bottom plate of the pressure relief channel (210) inside the shell (300), the waterproof plate (220) is arranged between the shell (300) and the anti-toxic structure (230), and the waterproof plate (220) is gradually arranged away from the shell (300) from bottom to top, a drainage part (320) is arranged at the connecting position of the shell (300) and the bottom of the pressure relief channel (210), and the drainage part (320) is used for draining water blocked by the waterproof plate (220).

5. The energy storage system of claim 4, wherein, The waterproof plate (220) comprises a water guide slope (221) and a waterproof main plate (222), the water guide slope (221) is arranged between the shell (300) and the waterproof main plate (222), and the water guide slope (221) is gradually arranged from one end close to the shell (300) to the end connected with the waterproof main plate (222), and the waterproof main plate (222) is gradually arranged away from the shell (300) from bottom to top.

6. The energy storage system of claim 5, wherein, The upper end of the waterproof main plate (222) is spaced apart from the inner wall surface of the upper side of the pressure relief channel (210).

7. The energy storage system of claim 5, wherein, A one-way movable plate (223) is arranged on the waterproof main plate (222), the one-way movable plate (223) is rotationally connected with the waterproof main plate (222) and can be rotated to open in the direction of the shell (300) under a certain air pressure, and the spaces on both sides of the waterproof main plate (222) are connected.

8. A thermal runaway control method for an immersed energy storage system, for the energy storage system of any one of claims 1-7, characterized in that, The thermal runaway control method comprises the following steps: Step ST1: detecting the temperature rise rate v1 of the battery unit in the energy storage system and the air pressure value P1 on the upper side of the immersion cavity; Step ST2: comparing the temperature rise rate v1 of the battery unit with a preset temperature rise rate v2, comparing the air pressure value P1 on the upper side of the immersion cavity with a preset pressure threshold P2, when at least one of the comparison results satisfies v1≥v2 and P1≥P2, it is judged that the current battery unit is in thermal runaway, an alarm signal is sent out, and step ST3 is executed; when the comparison results satisfy v1 Step ST3: cutting off the power supply of the current battery unit, closing the liquid input pipeline, overflow pipeline and liquid output pipeline of the immersion tank assembly corresponding to the current battery unit, and discharging the high-pressure gas in the immersion tank assembly corresponding to the current battery unit through the pressure relief plate; Step ST4: continuously detecting the temperature change of the battery unit in thermal runaway and the air pressure value in the immersion tank assembly where the battery unit is located; Step ST5: when the temperature of the battery unit in thermal runaway decreases to below a first preset temperature threshold Q1, and the air pressure value in the immersion tank assembly where the battery unit is located is less than the preset pressure threshold P2, step ST6 is executed: Step ST6: Turn on the overflow pipeline, liquid evacuation pipeline and waste liquid pipeline to drain the immersion liquid in the immersion tank assembly where the thermal runaway battery cell is located into the waste liquid tank.

9. The thermal runaway control method of claim 8, wherein, The preset temperature rise rate v2 is between 1.8℃ / s and 2.2℃ / s, and the preset pressure threshold P2 is between 118KPa and 122KPa.

10. The thermal runaway control method of claim 8, wherein, In step S5, the first preset temperature threshold Q1 is between 50℃ and 60℃.

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