An immersion energy storage battery pack and a temperature control method thereof

Abstract

The application discloses an immersed energy storage battery pack and a temperature control method thereof. The battery pack comprises: a battery module composed of one or more battery modules (1); a battery pack box (2) for accommodating the battery module; a liquid outlet (3) and a liquid inlet (8) for the outflow and inflow of immersion liquid respectively; a liquid level adjusting mechanism (4) for adjusting the outflow amount of the immersion liquid; a spraying mechanism (9) for spraying the immersion liquid; a management control module (7) electrically connected with the battery module (1), the liquid level adjusting mechanism (4) and the spraying mechanism (9) for receiving the temperature and state information of the battery module (1). The application realizes the safety protection effect of greatly improving the thermal runaway and thermal runaway spread of the battery pack by using less immersion liquid and an efficient internal structure of the battery pack, and is not only energy-saving and environment-friendly, but also beneficial to the application of the battery pack in the related fields such as electric vehicles.

Description

Technical Field

[0001] This invention relates to the field of battery pack technology, and in particular to an immersion energy storage battery pack and its temperature control method. Background Technology

[0002] Against the backdrop of the accelerated global energy structure transformation towards cleaner and lower-carbon energy, the electrochemical energy storage industry has become a core technology supporting the construction of new power systems. In 2024, global shipments of energy storage cells reached 314.7 GWh, a year-on-year increase of 60%; China's cumulative installed capacity of new energy storage exceeded 58.52 million kilowatts, with a market size of 266.1 billion yuan. However, frequent safety accidents in energy storage systems (such as thermal runaway and fires) and battery performance degradation have become key bottlenecks restricting the sustainable development of the industry. In this context, the shortcomings of traditional energy storage systems in terms of insulation failure, thermal runaway protection, and high-efficiency explosion-proof capabilities are becoming increasingly apparent.

[0003] With the development of electrochemical energy storage technology, immersion liquid cooling technology has been increasingly applied to energy storage systems such as battery packs in recent years due to its superior performance in terms of cooling efficiency, efficiency improvement, and safety. Existing immersion energy storage battery packs achieve heat exchange by completely submerging the battery modules in an immersion liquid. This places high demands on the sealing of the battery pack. Furthermore, the immersion liquid itself is costly, and using a large amount of immersion liquid during complete immersion increases the overall cost of manufacturing the battery pack, as well as its total weight. This can negatively impact the driving range and performance of weight-sensitive applications, such as electric vehicles. Summary of the Invention

[0004] The purpose of this invention is to provide an immersion energy storage battery pack and its temperature control method, which aims to significantly improve the safety protection effect of thermal runaway and thermal runaway propagation of the battery pack with less immersion fluid and a more efficient internal structure, improve the application efficiency of immersion fluid, reduce the amount of immersion fluid used, and reduce costs.

[0005] To address the aforementioned problems, a first aspect of the present invention provides an immersion energy storage battery pack, comprising: a battery module, consisting of one or more battery modules 1; a battery pack housing 2 for housing the battery modules; an outlet 3 and an inlet 8, both disposed on the battery pack housing 2, for the outflow and inflow of immersion liquid, respectively; a liquid level regulating mechanism 4, disposed inside the battery pack housing 2 and near the outlet 3, having multiple liquid level regulating holes 43, 44, and 45 communicating with the outlet 3, and controlling the immersion liquid in the battery pack housing 2 to maintain it within a predetermined range by automatically regulating the outflow of immersion liquid; a spraying mechanism 9, disposed inside the battery pack housing 2 and above the battery modules, for spraying immersion liquid; and a management control module 7, electrically connected to the battery modules 1, the liquid level regulating mechanism 4, and the spraying mechanism 9, for monitoring the temperature and status information of the battery modules 1, and controlling the liquid level regulating mechanism 4 and the spraying mechanism 9 according to a preset temperature control strategy.

[0006] The battery pack of this invention features a unique structural design and efficient management and control. It can exchange heat and equalize the temperature of the battery modules with a small amount of immersion liquid, and achieve self-balancing of the immersion liquid level in the battery pack box through a liquid level adjustment mechanism. At the same time, the management and control module performs linkage control of the sealing module and the spraying mechanism. When the battery modules malfunction, the battery pack can quickly switch from normal working state to fire protection mode, thereby significantly improving the safety protection effect against thermal runaway and thermal runaway propagation of the battery pack.

[0007] Furthermore, the liquid level regulating mechanism 4 includes a sealing module 37, which is disposed above the liquid outlet 3 and seals the liquid outlet 3 according to the instructions of the management and control module 7; and the liquid level regulating holes 43, 44, and 45 are formed on the liquid level regulating module 33, which forms a hollow enclosure structure with the side of the battery pack housing 2 to separate the liquid outlet 3 from the immersion liquid inside the battery pack housing 2.

[0008] Furthermore, the sealing module 37 includes a slider 31 and a slider push rod 32. The slider 31 and the slider push rod 32 are connected. The slider 31 is connected to the slider push rod 32, and the slider push rod 32 can drive the slider 31 to seal the liquid outlet 3.

[0009] Furthermore, the spraying mechanism 9 includes: a spraying main pipe 25 having multiple through holes; and one or more variable diameter spraying pipes 26 installed at the through holes on the spraying main pipe 25 and communicating with the spraying main pipe 25 for spraying the immersion liquid.

[0010] Furthermore, the variable diameter spray pipe 26 is provided with a plurality of holes 30 for spraying the immersion liquid.

[0011] Furthermore, the variable diameter spray pipe 26 is detachable, allowing for the replacement of variable diameter spray pipes 26 with different diameters and hole sizes to adjust the spray volume in each area.

[0012] When applying the battery pack provided by this invention, the spray volume of each area can be adjusted by replacing the variable diameter spray pipes at different positions, thereby achieving a uniform spraying effect.

[0013] Further, the spraying mechanism 9 includes: a series spraying structure 91 and / or a parallel spraying structure 92; the series spraying structure 91 includes a spray inlet connector 22, an inlet adapter 23, an adapter 24, the main spraying pipe 25, and the variable diameter spraying pipe 26 connected in sequence and installed sequentially; the parallel spraying structure 92 includes a spray inlet connector 22, an inlet adapter 23, and two or more of the series spraying structures 91 connected in sequence.

[0014] Furthermore, the spray inlet connector 22 is connected to the inlet port 8 to receive the immersion liquid flowing in. One end of the inlet adapter 23 is connected to the spray inlet connector 22, and the other end is connected to the adapter 24. The other end of the adapter 24 is connected to the spray main pipe 25.

[0015] Furthermore, the battery module 1 further includes: a plurality of battery cells 20, which are laterally stacked along a direction perpendicular to the largest surface of the battery cells 20, wherein the largest surface of the battery cells 20 is the surface with the largest area; and a fluid microchannel 15, which is formed in a direction perpendicular to the laterally stacked direction of the plurality of battery cells 20.

[0016] Furthermore, the spray surface of the spray mechanism 9 is positioned above the fluid microchannel 15, so that the immersion liquid passes through the fluid microchannel 15 and the corresponding surface of the battery cell 20 under the action of spray pressure and its own gravity.

[0017] Furthermore, the battery module 1 also includes a flame-retardant, low thermal conductivity material 19 disposed on at least one side of the battery cell 20 along the stacking direction of the plurality of battery cells (20) to delay or block heat transfer between adjacent battery cells 20.

[0018] Furthermore, the battery module 1 also includes a thermosetting material 18, disposed in the gap reserved between the adjacent cells 20, for supporting the battery module 1 and suppressing heat spread when the battery module 1 is stacked; wherein, the fluid microchannel 15 is formed in the area enclosed by the flame-retardant low thermal conductivity material 19 and the thermosetting material 18.

[0019] The unique fluid microchannels in this invention enable rapid flow of the immersion liquid within the battery module, thereby promoting temperature uniformity within the battery module. Simultaneously, by utilizing the properties of flame-retardant, low thermal conductivity materials and thermosetting materials, mutual interference caused by heat generation between battery cells is prevented. Furthermore, the battery module's ability to prevent the spread of thermal runaway is enhanced, thus improving the overall safety of the battery module.

[0020] Furthermore, the battery pack also includes: a liquid storage tank 10, which receives and stores the immersion liquid flowing out from the liquid outlet 3; a pump 11, connected to the liquid storage tank 10, for conveying the immersion liquid; a heat exchange device 12, which receives the immersion liquid conveyed from the pump 11 and regulates the temperature of the immersion liquid, and is electrically connected to the management and control module 7, the heat exchange device 12 including three working modes: cooling, preheating, and energy-saving temperature equalization; and a filter 13, which adsorbs and filters impurities in the immersion liquid, one end of which is connected to the heat exchange device 12, and the other end of which is connected to the liquid inlet 8.

[0021] Furthermore, multiple submerged energy storage battery packs are connected in series and / or in parallel to form a battery cluster. The battery cluster includes a battery management system that manages the management control module 7, or the battery cluster includes a battery management system but does not include the management control module 7.

[0022] According to another aspect of the present invention, the present invention also provides a temperature control method for an immersion energy storage battery pack, the method comprising the following steps: Step S1, turning on the battery pack, the battery pack entering a normal operating mode, the slider 31 being in the initial slider position 34, and the immersion liquid circulating in the battery pack for continuous heat exchange of the battery modules; Step S2, after the battery pack is turned on, the management control module 7 monitors the temperature of the battery cells 20 and / or the temperature of the immersion liquid in real time; Step S3, when the management control module 7 detects an abnormal increase in the temperature of the battery cells 20 and / or an abnormal increase in the temperature of the immersion liquid exceeding the maximum value of the preset normal temperature, the management control module 7 controls the pump 11 to increase its power to increase the flow rate of the immersion liquid, thereby accelerating the heat exchange and temperature equalization of the battery modules by the immersion liquid; Step S4, ... When the management and control module 7 detects that the temperature of the battery cell 20 and / or the temperature of the immersion liquid are greater than or equal to the phase change point temperature of the immersion liquid, the battery pack enters the fire protection mode. The management and control module 7 controls the slider 31 to slide down to the slider blocking position 35 to completely block the outlet 3. At the same time, the pump 11 is controlled to increase its power again to increase the flow rate of the immersion liquid until the immersion liquid completely submerges the battery module. During this process, some of the immersion liquid absorbs heat and vaporizes, and is discharged through the pressure relief valve on the top cover. In step S5, when the management and control module 7 detects that the temperature of the battery cell 20 and / or the temperature of the immersion liquid decreases to the minimum value of the preset normal temperature, the battery pack ends the fire protection mode. The management and control module 7 controls the slider 31 to return to the slider initial position 34. The excess immersion liquid flows back from the outlet 3 to the storage tank 10 through the liquid level adjustment module 33.

[0023] Further, step S1 includes: step S11, when the battery pack is turned on, the management control module 7 detects the internal environment of the battery pack housing 2 and the initial temperature of the battery cells 20 in the battery module; step S12, based on the internal environment of the battery pack housing 2 and the initial temperature of the battery cells 20 in the battery module, the operating mode of the heat exchange device 12 under different preset temperature ranges is determined, the management control module 7 shares battery pack data in real time and provides it to the heat exchange device, the heat exchange device 12 responds to the command of the management control module when it starts, automatically enters the corresponding operating mode, and reports its operating mode to the management control module; step S13, the pump 11 and the heat exchange device 12 are started, the immersion liquid flows from the storage tank 10 through the pump 11 through the battery pack housing 2 and the filter 13, and then enters the spraying mechanism 9 through the inlet 8, the spraying mechanism 9 sprays the battery module The immersion liquid is sprayed, and under the spray pressure and its own gravity, the immersion liquid quickly passes through the fluid microchannel 15 and the surface of the battery cell 20 to achieve heat exchange for the battery module. After heat exchange, the immersion liquid collects at the bottom of the battery pack housing 2, and after being regulated and controlled by the liquid level adjustment mechanism 4, it flows back to the liquid storage tank 10 through the liquid outlet 3. When the battery pack is working, the immersion liquid repeatedly circulates through this process to achieve continuous heat exchange or temperature equalization for the battery module. In step S14, after the battery pack is working, the management control module 7 monitors the internal environment of the battery pack housing 2 and the temperature of the battery cell 20 in the battery module in real time. In step S15, the operating mode of the heat exchange device 12 under different preset temperature ranges is determined according to the internal environment of the battery pack housing 2 and the temperature of the battery cell 20 in the battery module. The management control module 7 controls the heat exchange device 12 to switch between different operating modes.

[0024] Furthermore, step S4 also includes: when a portion of the battery cell 20 enters thermal runaway or thermal runaway propagates due to internal or external factors, the temperature of the battery cell 20 rises abnormally and is accompanied by an abnormal increase in internal pressure, the battery cell explosion-proof valve ruptures or the battery outer packaging is broken, the harmful gases, combustibles and other harmful substances generated by the thermal runaway or thermal runaway propagation of the portion of the battery cell 20 are first diluted by the immersion liquid, and at the same time the immersion liquid absorbs heat through phase change, converting the heat energy released by the battery thermal runaway into the heat of vaporization, and after vaporization, the immersion liquid is discharged through the pressure relief valve on the top cover, and at the same time the immersion liquid enters the interior of the portion of the battery cell 20 to dilute the electrolyte and block the electrochemical reaction.

[0025] The above-described technical solution of the present invention has the following beneficial technical effects:

[0026] 1. Compared with existing technologies, this technology significantly improves the safety protection against thermal runaway and its propagation by using less immersion fluid and a more efficient internal battery pack structure. It also improves the efficiency of immersion fluid application. The reduction in immersion fluid usage not only lowers costs and saves energy and is environmentally friendly, but also facilitates the application of battery packs in electric vehicles and related fields.

[0027] 2. The liquid level regulating mechanism inside the battery box achieves self-balancing of the immersion liquid level by adjusting the outflow at different liquid levels. Based on the self-balancing design of the liquid level regulating mechanism, it eliminates the need for conventional flow detection and control units with self-loss properties (e.g., flow meters, level gauges, and solenoid valves), thus avoiding the risk of liquid level control failure due to the insensitivity of electrical components after long-term use.

[0028] 3. The spraying mechanism adjusts the spray volume in each area by changing the variable diameter spray pipes at different positions to achieve a uniform spraying effect and avoid other problems caused by uneven heat exchange of the battery module due to uneven spraying.

[0029] 4. Continuous spraying is achieved under the coordinated control of the management and control module and the heat exchange device. When the battery thermal runaway is caused by various internal and external factors, the battery pack automatically starts the fire protection mode. The seamless switching from the normal working mode (immersion liquid convection heat exchange mode) to the fire protection mode (fire explosion-proof mode) realizes the speed and spontaneity of battery pack safety protection.

[0030] 5. The battery pack utilizes the unique fluid microchannel design and the battery module spray surface design that works in conjunction with the fluid microchannel to achieve high thermal conductivity with minimal distance in the vertical direction of battery module stacking; simultaneously, it employs flame-retardant, low thermal conductivity materials to achieve high thermal resistance in the direction of dense cell stacking. High thermal conductivity improves the thermal management efficiency of the battery module and promotes temperature uniformity within the battery module; high thermal resistance prevents mutual interference caused by heat generation between cells and enhances the battery module's ability to prevent the spread of thermal runaway, thereby improving the overall safety of the battery module. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an immersed energy storage battery pack according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of a liquid level regulating mechanism according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of a series spray structure in a specific embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of a parallel spray structure in a specific embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram of different spraying directions of multiple holes on a variable diameter spray pipe in a specific embodiment of the present invention;

[0036] Figure 6 This is a top view of a battery module according to an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of a battery cluster composed of two or more battery packs connected in parallel, according to a specific embodiment of the present invention.

[0038] Figure label:

[0039] 1: Battery module; 2: Battery pack housing; 3: Liquid outlet; 4: Liquid level adjustment mechanism; 5: Main positive connector of the battery pack; 6: Main negative connector of the battery pack; 7: Management and control module; 8: Liquid inlet; 9: Spraying mechanism; 10: Liquid storage tank; 11: Pump; 12: Heat exchange device; 13: Filter; 14: Cell terminal; 15: Fluid microchannel; 16: Battery module limiting end plate; 17: Elastic foam; 18: Thermosetting material; 19: Flame-retardant low thermal conductivity material; 20: Battery cell; 22: Spray inlet connector; 23: Inlet adapter; 24: Adapter; 25: Main spray pipe; 26: Variable diameter spray pipe; 27: Inlet adapter (parallel spray structure); 28: Main spray pipe (parallel spray structure); 29: Immersion liquid flow direction; 30: Multiple holes on the variable diameter spray pipe; 31: Slider; 32: Slider push rod; 33: Liquid level adjustment module; 34: Initial position of slider; 35: Slider blocking position; 37: Blocking module; 39: Secondary inlet pipe; 40: Primary inlet pipe; 41: Secondary outlet pipe; 42: Primary outlet pipe; 43: Initial liquid level adjustment hole; 44: Liquid level adjustment hole; 45: Upper limit liquid level adjustment hole; 91: Series spray structure; 92: Parallel spray structure. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0041] The following is combined Figures 1 to 7 The immersion energy storage battery pack provided by the present invention will be described.

[0042] Figure 1 This is a schematic diagram of an immersed energy storage battery pack according to an embodiment of the present invention.

[0043] like Figure 1As shown, the battery pack of this embodiment includes: a battery module composed of multiple battery modules 1, a battery pack housing 2 for placing the battery modules, an outlet 3 and an inlet 8 for the immersion liquid, a liquid level regulating mechanism 4 for adjusting the outflow of the immersion liquid, a main positive connector 5 for the battery pack, a main negative connector 6 for the battery pack, a spraying mechanism 9 above the battery modules, a management and control module 7, a liquid storage tank 10, a pump 11 for conveying the immersion liquid, a heat exchange device 12 for adjusting the temperature of the immersion liquid, a filter 13 for adsorbing and filtering the immersion liquid, and various auxiliary connecting parts. Figure 1 In the process, the submerged energy storage battery pack is placed horizontally, and the battery modules 1 are stacked vertically inside the battery pack housing 2.

[0044] See Figure 1 and combined Figure 4 and Figure 5 As shown, in some embodiments, when the battery pack is in use, the immersion liquid enters the spray mechanism 9 from the inlet 8, such as... Figure 1As shown, the spraying mechanism 9 is a parallel spraying structure 92. The parallel spraying structure 92 is composed of a spray inlet connector 22, an inlet adapter 23 with one end sealed, two inlet adapters (parallel spraying structures) 27, two adapters 24, two spray mains (parallel spraying structures) 28, and multiple variable diameter spray pipes 26, which are sequentially connected. The variable diameter spray pipes 26 are installed at the through holes on the spray mains (parallel spraying structures) 28 and communicate with them. The variable diameter spray pipes 26 have multiple holes 30 for spraying immersion liquid onto the battery module. Under the spraying pressure and its own gravity, the immersion liquid quickly passes through the fluid microchannels 15 in the battery module and the surface of the cells 20 to the bottom of the battery pack housing 2. The fluid microchannels 15 are formed in the vertical direction of the lateral stacking direction of the multiple cells 20, specifically by pre-setting between adjacent cells 20. The thermosetting material 18 in the gaps and the flame-retardant, low thermal conductivity material 19 on the side of the cell 20 are used to enclose the gaps between adjacent cells 20. When the cells 20 are stacked in multiple layers, the fluid microchannels 15 extend longitudinally along the stacking direction of the cells 20 and expand laterally between adjacent cell 20 layers, thus forming a crisscrossing fluid channel. When the immersion liquid passes through the holes 30 on the variable diameter spray pipe 26 to the outer surface of the battery module 1, the immersion liquid flows through the surface of the cell 20 from the path formed on the side of the cell 20 for heat exchange. In specific implementation, multiple holes 30 are opened on one side of the variable diameter spray pipe. When the immersion liquid is sprayed, the holes are sprayed in different directions. Through fluid simulation, the flow resistance and required flow rate of the holes of the variable diameter spray pipe in each area are calculated. At the same time, the variable diameter spray pipe 26 can be replaced in real time to adjust the spray volume of each area, thereby achieving a uniform spraying effect. After heat exchange, the immersion liquid collects at the bottom of the battery pack housing 2. After being regulated and controlled by the liquid level adjustment mechanism 4, it flows out of the battery pack housing 2 through the liquid outlet 3 and returns to the liquid storage tank 10. After being pumped by the pump 11, the immersion liquid is transported to the heat exchange device 12. After completing the heat exchange treatment, the immersion liquid flows to the filter 13. The filter 13 adsorbs and filters the impurities in the immersion liquid. After completion, the immersion liquid enters the spraying mechanism 9 again from the liquid inlet 8. During the normal operation of the battery pack, the immersion liquid repeatedly circulates through this process to achieve continuous heat exchange for the battery module. Meanwhile, the management and control module 7 is electrically connected to the battery module 1, the liquid level adjustment mechanism 4, the spray mechanism 9, and the heat exchange device 12, so that the management and control module 7 can monitor the temperature and status information of the battery module 1 in real time, and control the sealing module 37 to seal the liquid outlet 3 according to the set temperature control strategy. At the same time, the management and control module 7 controls the start and stop of the spray mechanism 9, the spray frequency and spray volume, and the working mode of the heat exchange device 12 in real time, thereby achieving coordinated heat exchange and real-time temperature management of the battery pack.

[0045] In some embodiments, the heat exchange device 12 operates in three modes: cooling, preheating, and energy-saving temperature equalization. When the heat exchange device 12 is in cooling mode, the immersion liquid is cooled, and the cooled immersion liquid exchanges heat with the battery module 1, which is the cooling mode. When the heat exchange device 12 is in preheating mode, the immersion liquid is preheated, and the heated immersion liquid exchanges heat with the battery module 1, which is the preheating mode. When the battery temperature is moderate and does not meet the requirement for the heat exchange device 12 to start preheating or cooling, only the pump 11 is turned on. At this time, the temperature equalization of the battery cells 20 in the battery pack is achieved by utilizing contact heat exchange and the specific heat capacity of the immersion liquid. In this mode, neither cooling nor preheating is activated, the system consumes less power, and it is the energy-saving temperature equalization mode. The three functional modes of cooling, preheating, and temperature equalization are intelligent and reversible switching under normal heat exchange conditions.

[0046] Figure 2 This is a schematic diagram of a liquid level regulating mechanism in an embodiment of the present invention.

[0047] like Figure 2 As shown, the liquid level regulating mechanism 4 includes a liquid level regulating module 33 and a sealing module 37. The liquid level regulating module 33 forms a hollow enclosure structure with the side of the battery pack housing 2, separating the outlet 3 from the immersion liquid inside the battery pack housing 2. The liquid level regulating module 33 has an initial liquid level regulating hole 43, multiple liquid level regulating holes 44, and an upper limit liquid level regulating hole 45. These liquid level regulating holes are all connected to the outlet 3. The liquid level regulating module 33 automatically regulates the outflow of the immersion liquid through these liquid level regulating holes to control the immersion liquid inside the battery pack housing 2 to remain within a predetermined range. The sealing module 37 is located above the outlet 3 and includes a slider 31 and a slider push rod 32. The slider 31 and slider push rod 32 are connected, with the slider 31 connected to the slider push rod 32. The slider push rod 32 can drive the slider 31 to seal the outlet 3. (See also...) Figure 2 In some embodiments, the liquid level regulating mechanism 4 of the present invention includes a blocking module 37 and a liquid level regulating module 33. The blocking module 37 is disposed above the liquid outlet 3 and can block the liquid outlet 3 according to the instructions of the management and control module 7. The liquid level regulating module 33 forms a hollow enclosure structure with the side of the battery pack housing 2 to separate the liquid outlet 3 from the immersion liquid in the battery pack housing 2. The liquid level regulating module 33 has multiple liquid level regulating holes 43, 44, and 45, which are connected to the liquid outlet 3. The liquid level regulating mechanism 4 controls the immersion liquid in the battery pack housing 2 to be kept within a predetermined range by automatically adjusting the outflow of the immersion liquid. The blocking module 37 consists of a slider 31 and a slider push rod 32. The blocking instruction of the management and control module 7 is actually executed by the slider push rod 32, which moves downward and drives the slider 31 to move downward, thereby blocking the liquid outlet 3. The slider 31 can be a cuboid, cylinder, sphere, or wedge-shaped structure. The structure of the slider 31 depends on the structure of the liquid outlet 3 and the motion trajectory designed for the sealing module 37.

[0048] In other embodiments, the outlet 3 is a non-circular tubular structure, and the slider blocking position 35 is designed to be located at the front end of the outlet 3. For the lateral or longitudinal movement trajectory of the blocking module 37, the slider 31 adopts a fitting structure similar in shape to the outlet 3 to facilitate implementation.

[0049] See Figure 2 In a specific embodiment, the outlet 3 is a circular tubular structure, the slider blocking position 35 is designed to be located at the front end of the outlet 3, and the motion trajectory of the blocking module 37 is designed to be from top to bottom with respect to the longitudinal direction of the outlet 3. Both the slider 31 and the slider push rod 32 adopt a cuboid structure for ease of implementation.

[0050] In another specific implementation, the outlet 3 is a circular tubular structure, and the slider blocking position 35 is designed to be located at the front end of the outlet 3. The lateral movement trajectory of the blocking module 37 is designed to be from left to right or from front to back, based on the lateral direction of the outlet 3. It is more convenient to implement the slider 31 by adopting a spherical or cylindrical structure.

[0051] See Figure 2 In some embodiments, the slider push rod 32 and the slider 31 are integrally connected or separately connected. The slider 31 is connected to the slider push rod 32, and the slider push rod 32 is above the slider 31. The slider 31 is located above the liquid outlet 3. The management and control module 7 can control the slider push rod 32 to move up and down, so that the slider 31 can block the liquid outlet 3 under the action of the slider push rod 32. The liquid level adjustment module 33 and the side of the battery pack housing 2 form a hollow enclosure structure to separate the liquid outlet 3 from the immersion liquid in the battery pack housing 2. An initial liquid level adjustment hole 43, two liquid level adjustment holes 44, and an upper limit liquid level adjustment hole 45 are opened on the liquid level adjustment module 33. The diameters of these liquid level adjustment holes are arranged from large to small and from top to bottom, and all of them are connected to the liquid outlet 3. The liquid level adjustment module 33 automatically adjusts the outflow of immersion liquid through these liquid level adjustment holes to control the immersion liquid in the battery pack housing 2 to remain within a predetermined range, so as to achieve the effect of liquid level self-balancing.

[0052] Liquid level self-balancing refers to the ability of a container or system to automatically maintain a consistent liquid level or a predetermined liquid level through its inherent structure or simple mechanical principles, without external power (such as a water pump) or complex control systems (such as sensors or PLCs).

[0053] The working principle of the liquid level regulating mechanism used in this invention is as follows: Self-balancing liquid level control based on outflow is achieved through the design of liquid level regulating holes at the tank outlet. The design of the liquid level regulating holes mainly focuses on the calculation of the cross-sectional area of ​​the hole and the flow rate at that section. The number of liquid level regulating holes is ≥3, and the cross-sectional design of the liquid level regulating holes depends on the design position of the "balance liquid level line." The "balance liquid level line" refers to the equilibrium point where the inflow of liquid into the tank is approximately equal to the outflow when the submerged liquid level is at this height. When the liquid level in the tank is below this equilibrium point, the inflow of the spray system is greater than the outflow of the submerged liquid, and the liquid level in the tank rises. When the liquid level in the tank is above this equilibrium point, the outflow of the submerged liquid is greater than the inflow of the spray system. For outlets below the "balance liquid level line," the cumulative outflow of liquid at different heights is less than the inflow of the spray system. For outlets above the "balance liquid level line," the cumulative outflow is greater than that at the tank inlet. The self-balancing design of the tank's liquid level is achieved by controlling the liquid output through a liquid level adjustment orifice. This eliminates the need for conventional flow detection and control units such as flow meters, level gauges, and solenoid valves, which increase the self-consumption of the battery pack and avoid the risk of liquid level control failure due to electrical component failure over long-term use. The liquid level adjustment used in this invention maintains a basically constant liquid inflow to the tank spray system under the same operating mode, ensuring the basic thermal management requirements of the battery under a given operating module.

[0054] The design principle of the liquid outlet of this invention is as follows: First, thermal simulation is used to determine the basic amount of spray immersion liquid required by the battery pack under a set operating mode. Based on the basic amount of spray immersion liquid, the position of the "equilibrium liquid level line" of each battery pack in the system is determined, and then the number and cross-section of the liquid level adjustment holes are determined. By determining the "equilibrium liquid level line", the basic amount of immersion liquid is cyclically maintained in the submerged energy storage system.

[0055] In some embodiments, the shape of the liquid level regulating orifice is not limited, and it can be a common cylindrical, cuboid, regular cube, or irregular cube shape. For example, the liquid level regulating orifice provided in the accompanying drawings is cylindrical (the cross-section of the liquid level regulating orifice is circular), but it can also be cuboid (the cross-section of the liquid level regulating orifice is rectangular), regular cube (the cross-section of the liquid level regulating orifice is polygonal), or irregular cube (the cross-section of the liquid level regulating orifice is irregular), etc. The specific orifice diameter and orifice spacing of the liquid level regulating orifice are designed and arranged according to the actual drainage requirements.

[0056] See Figure 2In some embodiments, the liquid level adjustment module 33 controls the outflow of the immersion liquid through liquid level adjustment holes corresponding to different liquid level heights, thereby achieving self-balancing of the immersion liquid level inside the battery pack housing 2. The self-balancing liquid level control design based on outflow is the result of comprehensive calculation of the structural functions of the liquid level adjustment module 33, the outlet 3, the slider 31 that blocks the outlet, and the spray inflow and gravity outflow inside the battery pack housing 2. Among them, the spray inflow inside the battery pack housing 2 is determined by the heat generation and basic fire protection requirements under the battery pack operating conditions, and the spray outflow inside the battery pack housing 2 must meet the following requirement: maximum outflow ≥ maximum inflow. The liquid level adjustment module 33 controls the outflow at different liquid levels to achieve a self-balancing "fluctuation maintenance" state of the liquid level. The working process of the liquid level adjustment mechanism 4 is as follows: The battery pack is turned on, entering normal operating mode. The slider 31 is in its initial position 34. When spraying begins, the immersion liquid inside the battery pack housing 2 flows out, gradually accumulating at the bottom of the battery pack housing 2. As the spraying volume increases, the liquid level inside the battery pack housing 2 gradually rises. As the liquid level rises, it touches the upper limit liquid level adjustment hole 45 with the largest diameter on the liquid level adjustment module 33, causing the outflow rate to continuously increase. As the liquid level drops, it touches the corresponding liquid level adjustment hole 44. During this process, the outflow... When the amount of liquid entering the battery pack housing 2 is greater than the amount of liquid sprayed into the housing, the liquid level inside the battery pack housing 2 continues to drop. The diameter of the outlet holes on the liquid level adjustment module 33 gradually decreases, and the outflow gradually decreases until the liquid level reaches the initial liquid level adjustment hole 43. When the outflow from the initial liquid level adjustment hole 43 is less than the amount of liquid sprayed into the battery pack housing 2, the liquid level rises again. This repeated adjustment forms a liquid level self-balancing design based on outflow control, thereby maintaining the amount of liquid sprayed into the housing under the same working mode at a basically constant level, ensuring the basic thermal management requirements of the battery under the given working module.

[0057] When the battery pack enters the fire protection mode, the management control module 7 controls the slider push rod 32 to move downward. The slider 31 slides downward under the action of the slider push rod 32 until it reaches the slider blocking position 35, which completely blocks the liquid outlet 3. At the same time, the management control module 7 controls the pump 11 to increase its power to increase the flow rate of the immersion liquid until the immersion liquid completely submerges the battery module. When the battery pack ends the fire protection mode, the management control module controls the slider push rod 32 to move upward. The slider 31 slides upward under the action of the slider push rod 32 until it returns to the slider initial position 34. During the upward sliding of the slider 31, the immersion liquid in the battery pack housing 2 passes through the liquid level adjustment holes 43, 44, and 45 of the liquid level adjustment module 33 in sequence and flows back from the liquid outlet 3 to the storage tank 10.

[0058] Figure 3 This is a schematic diagram of a series spray structure in a specific embodiment of the present invention.

[0059] like Figure 3As shown, the series-connected spray structure 91 is constructed by sequentially installing a spray inlet connector 22, a spray inlet adapter 23, an adapter 24, a spray main pipe 25, and multiple variable-diameter spray pipes 26, as well as other auxiliary materials. One end of the spray inlet adapter 23 is connected to the spray inlet connector 22, one end of the adapter 24 is connected to the other end of the spray inlet adapter 23, one end of the spray main pipe 25 is connected to the other end of the adapter 24, and the other end is blocked. Multiple variable-diameter spray pipes 26 are installed at the through holes opened on the spray main pipe 25 and are connected to the spray main pipe 25.

[0060] See Figure 3 In one specific embodiment, the spray mechanism 9 of the battery pack adopts a series spray structure 91. The spray inlet connector 22 is installed at the inlet 8 to receive the inflowing immersion liquid. One end of the inlet adapter 23 is connected to the spray inlet connector 22, and the other end is connected to the adapter 24. The other end of the adapter 24 is connected to the spray main pipe 25. Multiple through holes are opened on the spray main pipe 25, and the other end is sealed. The variable diameter spray pipe 26 is installed at the through holes opened on the spray main pipe 25. The multiple holes opened are connected to the spray main pipe 25 for spraying the immersion liquid. At the same time, the variable diameter spray pipe 26 can be replaced in real time to adjust the spray volume of each area to achieve a uniform spraying effect.

[0061] Figure 4 This is a schematic diagram of a parallel spray structure in a specific embodiment of the present invention.

[0062] like Figure 4 As shown, the parallel spray structure 92 includes a spray inlet connector 22, an inlet adapter 23 with one end sealed, and two series spray structures 91 connected in sequence. Specifically, the parallel spray structure 92 is constructed by sequentially installing two inlet adapters (parallel spray structures) 27, two adapters 24, two main spray pipes (parallel spray structures) 28, multiple variable diameter spray pipes 26, and other auxiliary materials. The variable diameter spray pipes 26 are installed at the through holes opened on the main spray pipes (parallel spray structures) 28 and connected to them.

[0063] Figure 5 This is a schematic diagram of different spraying directions of multiple holes on a variable diameter spray pipe in a specific embodiment of the present invention.

[0064] like Figure 5 As shown, the variable diameter spray pipe 26 has multiple holes 30, which can spray the immersion liquid from multiple different directions at the same time.

[0065] Figure 6 This is a top view of a battery module according to an embodiment of the present invention.

[0066] like Figure 6As shown, the cells 20 are stacked horizontally along a direction perpendicular to the largest surface of the cell 20. The largest surface of the cell 20 is the surface with the largest area. Multiple cells 20 are arranged horizontally in sequence, with gaps reserved between adjacent cells 20. Flame-retardant and low thermal conductivity material 19 is disposed on the side surface of the cell 20 along the stacking direction of the cell 20 to delay or block heat transfer between adjacent cells 20. Multiple block-shaped thermosetting materials 18 are disposed in sequence in the gaps reserved between adjacent cells 20. When the battery module 1 is stacked, the block-shaped thermosetting materials 18 play a supporting role and inhibit heat spread. The fluid microchannel 15 is formed by the area enclosed by the flame-retardant and low thermal conductivity material 19 and the thermosetting materials 18. When multiple layers of cells 20 are stacked, the fluid microchannel 15 extends longitudinally along the stacking direction of the cell 20 and expands laterally between adjacent layers of cells 20, thereby forming a crisscrossing fluid channel.

[0067] See Figure 6In some embodiments, the battery module 1 is constructed by assembling and repeatedly stacking multiple energy storage cells 20, flame-retardant and low thermal conductivity material 19 and thermosetting material 18 attached to the sides of the cells 20, and fluid microchannels 15 formed between them. The cells 20 are used for the storage and conversion of electrical and chemical energy. The cells 20 are connected in series and parallel to form the main body of the battery module 1. An explosion-proof valve is provided on the cells 20 to release the gas generated inside the cells 20 when an abnormality occurs. The structure of fluid microchannels 15 is formed between one or more cells 20 in the battery module 1. The fluid microchannels 15 are formed by thermosetting material 18 in the stacking direction of the cells 20 and flame-retardant and low thermal conductivity material 19 attached to the sides of the cells 20 in the gaps reserved between adjacent cells 20. When the cells 20 are stacked in multiple layers, the fluid microchannels 15 extend longitudinally along the stacking direction of the cells 20 and expand laterally between adjacent layers of cells 20, thereby forming crisscrossing fluid channels. The spray surface of the spray mechanism 9 is located above the structure of the fluid microchannel 15. The immersion liquid is sprayed onto the spray surface of the battery module 1. The liquid forms a free fall motion and uses the spray pressure and its own gravity to quickly pass through the fluid microchannel 15 and the corresponding surface of the battery cell 20, forming a direct contact and efficient heat exchange with the battery cell 20 during charging and discharging. Specifically, after the immersion liquid is sprayed from the spray mechanism 9, it flows along the top-to-bottom fluid microchannel 15. During this process, the immersion liquid flows over the side of the horizontally placed battery cell 20, exchanging heat with the battery cell 20. Since the battery cell 20 is horizontally placed, the immersion liquid can quickly flow over the surface of the battery cell 20. Compared with the vertically placed battery cell, the flow path of the immersion liquid is significantly shortened and is the shortest path. Therefore, this embodiment utilizes the structure of the fluid microchannel 15 to achieve the shortest heat exchange path for the battery module 1. Through the specific structure of the fluid microchannel 15 and the spray surface design of the battery module that cooperates with it, the battery module 1 achieves a high thermal conductivity effect with the shortest distance in the vertical direction of the battery module 1 stack. The spray surface design of the battery module is determined by the specific position of the spray structure 9 installed above the battery module. At the same time, high thermal resistance is achieved in the direction of dense stacking of the battery cells 20 using flame-retardant low thermal conductivity material 19, and the thermal conductivity of the flame-retardant low thermal conductivity material 19 is ≤0.3W / (mk). High thermal conductivity improves the thermal management efficiency of the submerged battery module and promotes module temperature uniformity. When a cell malfunctions, high thermal resistance prevents mutual interference of heat generation between cells 20, while enhancing the battery module 1's ability to prevent the spread of thermal runaway and improving the safety of the battery module. When the battery pack enters the fire protection mode, the abnormal temperature rise of some cells 20 causes the internal pressure of cells 20 to rise, resulting in the cell explosion-proof valve breaking. At this time, the immersion liquid enters the cell 20 to dilute the electrolyte and block the electrochemical reaction. At the same time, some of the immersion liquid absorbs heat and vaporizes. The gas that accumulates in the battery pack housing 2 is discharged through the pressure relief valve on the battery pack cover.

[0068] Figure 7 This is a schematic diagram of a battery cluster composed of two or more battery packs connected in parallel, according to a specific embodiment of the present invention.

[0069] like Figure 7 As shown, the battery cluster is composed of multiple submerged energy storage battery packs connected in parallel. It also includes a liquid storage tank 10, a pump 11 for conveying the submerged liquid, a heat exchanger 12 for regulating the temperature of the submerged liquid, a filter 13 for adsorbing and filtering the submerged liquid, and various auxiliary connecting components. See also... Figure 7 In some embodiments, two or more submerged energy storage battery packs are connected in series and / or in parallel to form a battery cluster, which includes a battery management system that manages the management control module 7, or the battery cluster includes a battery management system but does not include the management control module 7.

[0070] When the battery cluster is activated, it enters normal operating mode. Two or more sets of sliders 31 are in their initial positions 34. Immersion fluid circulates within the battery packs to continuously heat the battery modules. The battery management system monitors the cell temperature 20 in real time. When the system detects an abnormal temperature rise exceeding the preset maximum normal temperature, it controls the pump 11 to increase its power, thereby increasing the immersion fluid flow rate and accelerating heat exchange between the immersion fluid and the battery modules. When the system detects that the cell temperature 20 is greater than or equal to the immersion fluid's phase change point temperature, the battery cluster enters a fire suppression mode. The battery management system or management control module 7 controls the slider push rod 32 in each battery pack to move downwards. The slider 31 slides downwards under the influence of the slider push rod 32 until it reaches the slider sealing position 35 and completely seals the outlet. 3. Simultaneously, the pump 11 is controlled to increase its power again to further increase the flow rate of the immersion liquid until the immersion liquid completely submerges the battery modules in each battery pack. During this process, some of the immersion liquid absorbs heat and vaporizes, and is discharged through the pressure relief valve on the top cover. When the battery management system or management control module 7 detects that the temperature of the cell 20 has dropped to the minimum value of the preset normal temperature, the battery cluster ends the fire protection mode. The battery management system or management control module 7 controls the slider push rod 32 in each battery pack to move upward. The slider 31 slides upward under the drive of the slider push rod 32 until the slider 31 returns to the initial position 34. When the slider 31 slides upward, the immersion liquid can flow out normally from the outlet 3. At this time, the immersion liquid in each battery pack box 2 passes through the liquid level adjustment holes 43, 44, and 45 of their respective liquid level adjustment modules 33 in sequence, and then flows back to the storage tank 10 through the outlet 3.

[0071] The present invention also provides a temperature control method for an immersed energy storage battery pack, which is used in an immersed energy storage battery pack. The temperature control method includes the following steps:

[0072] Step S1: The battery pack is turned on, and it enters normal operating mode. Slider 31 is in its initial position 34, and the immersion liquid circulates within the battery pack to continuously heat the battery modules. Further, Step S1 includes: Step S11: When the battery pack is turned on, the management control module 7 detects the internal environment of the battery pack housing 2 and the initial temperature of the battery cells 20 in the battery modules; Step S12: Based on the internal environment of the battery pack housing 2 and the initial temperature of the battery cells 20 in the battery modules, the management control module 7 determines the operating mode of the heat exchange device 12 within different preset temperature ranges. The management control module 7 shares battery pack data in real time with the heat exchange device. When the heat exchange device 12 starts, it responds to the instructions of the management control module 7 and automatically enters the corresponding operating mode. The system operates in a specific mode and reports its operating mode to the management and control module 7. In step S13, the pump 11 and heat exchange device 12 are started. The immersion liquid flows from the storage tank 10 through the pump 11, passing through the battery pack housing 2 and the filter 13, and then enters the spraying mechanism 9 through the inlet 8. The spraying mechanism 9 sprays the immersion liquid onto the battery module. Under the spraying pressure and its own gravity, the immersion liquid quickly passes through the fluid microchannel 15 and the surface of the cell 20 to achieve heat exchange for the battery module. After heat exchange, the immersion liquid collects at the bottom of the battery pack housing 2. After being regulated and controlled by the liquid level adjustment mechanism 4, it flows back into the storage tank 10 through the outlet 3. When the battery pack is working, the immersion liquid repeatedly circulates through this process to achieve continuous heat exchange or temperature equalization for the battery module. Step S14: After the battery pack is working, the management and control module 7 monitors the internal environment of the battery pack housing 2 and the temperature of the battery cells 20 in the battery module in real time. Step S15: Based on the internal environment of the battery pack housing 2 and the temperature of the battery cells 20 in the battery module, the management and control module 7 determines the working mode of the heat exchange device 12 under different preset temperature ranges, and controls the heat exchange device 12 to switch between different working modes.

[0073] Step S2: After the battery pack is turned on, the management and control module 7 monitors the temperature of the battery cell 20 and / or the temperature of the immersion liquid in real time.

[0074] Step S3: When the management control module 7 detects that the temperature of the battery cell 20 rises abnormally and / or the temperature of the immersion liquid rises abnormally and exceeds the maximum value of the preset normal temperature, the management control module 7 controls the pump 11 to increase its power to increase the flow rate of the immersion liquid, thereby accelerating the heat exchange and temperature equalization of the battery module by the immersion liquid.

[0075] Step S4: When the management control module 7 detects that the temperature of the battery cell 20 and / or the temperature of the immersion liquid are ≥ the phase change point temperature of the immersion liquid, the battery pack enters the fire protection mode. The management control module 7 controls the slider 31 to slide down to the slider sealing position 35 to completely seal the outlet 3. At the same time, it controls the pump 11 to increase its power again to increase the flow rate of the immersion liquid until the immersion liquid completely submerges the battery module. During this process, some of the immersion liquid absorbs heat and vaporizes, and is discharged through the pressure relief valve on the top cover. Further, step S4 also includes: some of the battery cells 20 When thermal runaway or thermal runaway propagation occurs due to internal or external factors, the temperature of cell 20 rises abnormally and is accompanied by an abnormal increase in internal pressure. The cell's explosion-proof valve ruptures or the battery's outer packaging is broken. Harmful gases, combustibles, and other harmful substances generated by thermal runaway or thermal runaway propagation in some cells 20 are first diluted by the immersion liquid. At the same time, the immersion liquid absorbs heat through phase change, converting the heat energy released by the battery's thermal runaway into heat of vaporization. After vaporization, the immersion liquid is discharged through the pressure relief valve on the top cover. Simultaneously, the immersion liquid enters the interior of some cells 20 to dilute the electrolyte and block the electrochemical reaction.

[0076] Step S5: When the management control module 7 detects that the temperature of the cell 20 and / or the temperature of the immersion liquid have dropped to the minimum value of the preset normal temperature, the battery pack ends the fire protection working mode. The management control module controls the slider 31 of the 7 to return to the initial position 34 of the slider. The excess immersion liquid flows back from the outlet 3 to the storage tank 10 through the liquid level adjustment module 33.

[0077] In some embodiments, when the battery pack is turned on, it enters normal operating mode, with slider 31 in its initial position 34. Immersion fluid circulates within the battery pack, continuously exchanging heat with the battery modules. When the battery pack is turned on, the management control module 7 detects the internal environment of the battery pack housing 2 and the initial temperature of the battery cells 20 within the battery modules. Based on the specific value of the initial temperature, the management control module 7 controls the heat exchange device 12 to enter different operating modes upon startup. Specifically, the heat exchange device 12 includes three operating modes: cooling, preheating, and energy-saving temperature equalization. Each operating mode corresponds to a different preset temperature range. The management control module 7 compares the detected initial temperature with the preset temperature range and determines the operating mode of the heat exchange device 12 upon startup based on the temperature range within which the initial temperature falls. At this time, the management control module 7 shares battery pack data in real time with the heat exchange device. Upon startup, the heat exchange device 12 responds to the management control module's command, automatically entering the corresponding operating mode and simultaneously reporting its operating mode to the management control module 7. Next, the management and control module 7 starts the pump 11 and the heat exchange device 12. The immersion liquid flows from the storage tank 10 through the pump 11, sequentially through the battery pack housing 2 and the filter 13, and then enters the spraying mechanism 9 through the inlet 8. The spraying mechanism 9 sprays the immersion liquid onto the battery module. Under the spraying pressure and its own gravity, the immersion liquid quickly passes through the fluid microchannel 15 and the surface of the battery cell 20 and flows to the bottom of the battery pack housing 2. During the flow of the immersion liquid, heat exchange is achieved on the battery module. After heat exchange, the immersion liquid collects at the bottom of the battery pack housing 2. After being regulated and controlled by the liquid level adjustment mechanism 4, it flows back into the storage tank 10 through the outlet 3. When the battery pack is working, the immersion liquid repeatedly circulates through this process to achieve continuous heat exchange on the battery module. After the battery pack is working, the management and control module 7 monitors the internal environment of the battery pack housing 2, the temperature of the battery cell 20 and the busbar in the battery module in real time, and controls the heat exchange device 12 to switch between different working modes according to the monitored temperature.Simultaneously, the management control module 7 monitors the temperature of the battery cell 20 and the immersion liquid in real time. When the management control module 7 detects an abnormal rise in the temperature of the battery cell 20 exceeding the preset maximum normal temperature, it controls the pump 11 to increase its power to increase the flow rate of the immersion liquid, thereby accelerating the heat exchange process of the immersion liquid on the battery module. Next, when the management control module 7 detects that the temperature of the battery cell 20 is greater than or equal to the phase change point temperature of the immersion liquid, the battery pack enters the fire-fighting mode. The slider push rod 32 is controlled to move downwards, and the slider 31 slides downwards under the action of the slider push rod 32 until the slider 31 reaches the slider blocking position 35, which completely blocks the liquid outlet 3. At the same time, the pump 11 is controlled to increase the power again to increase the flow rate of the immersion liquid until the immersion liquid completely submerges the battery module. During this process, some cells 20 experience thermal runaway or thermal runaway propagation. The abnormal temperature rise of the cell 20 causes an abnormal increase in the internal pressure of the cell 20, which leads to the cell explosion-proof valve breaking or the battery packaging breaking. This allows the harmful gases and combustibles generated inside some abnormal cells 20 to be diluted by the immersion liquid and cooled down by absorbing heat. The immersion liquid enters the interior of some cells 20 to dilute the electrolyte and block the electrochemical reaction. At the same time, some of the immersion liquid absorbs heat and vaporizes. The gas that accumulates in the battery pack box 2 is discharged through the pressure relief valve on the top cover. Finally, when the management control module 7 detects that the temperature of the cell 20 or the temperature of the immersion liquid has dropped to the minimum value of the preset normal temperature, the battery pack ends the fire protection mode. The management control module 7 controls the slider push rod 32 to move upward. The slider 31 slides upward under the action of the slider push rod 32 until the slider 31 returns to the initial position 34. When the slider 31 slides upward, the immersion liquid can flow out normally from the outlet 3. At this time, the immersion liquid in the battery pack housing 2 passes through the liquid level adjustment holes 43, 44 and 45 of the liquid level adjustment module 33 in sequence, and then flows back to the storage tank 10 from the outlet 3.

[0078] The immersion liquid used in this invention has insulation properties that meet the requirement of dielectric strength ≥25KV. When the battery pack is working normally, the immersion liquid can directly contact the battery cell 20 and all conductive materials in the battery pack without affecting its insulation performance. In an environment of -40℃ to 120℃, the kinematic viscosity of the immersion liquid is ≤2cst, the specific heat is ≥0.9J / g.℃, and the freezing point is ≥-40℃. The immersion liquid contains, but is not limited to, perfluorocarbon compounds such as perfluorononene and perfluorohexene. The immersion fluid can directly exchange heat with the battery cells 20 and heating devices inside the battery pack. The immersion fluid is lightning-free, non-flammable, and absorbs heat during phase change with a phase change point between 40℃ and 120℃. It also possesses excellent oxidation and corrosion resistance, with an ozone depletion potential (ODP) of zero, making it environmentally friendly and pollution-free. This allows the immersion fluid to spontaneously trigger its phase change point (phase change point temperature range: 40℃~120℃, adjustable according to actual needs) from a heat exchange state when the battery experiences thermal runaway. It then vaporizes and absorbs heat, rapidly absorbing and vaporizing the heat generated by the battery's thermal runaway, and discharging it outside the enclosure through a pre-set pressure relief valve. Simultaneously, after the cell explosion-proof valve is opened or broken, the immersion fluid rapidly enters the cell 20, diluting the electrolyte and blocking the continued electrochemical reaction, completely releasing the energy stored in the cell 20. This phase change converts the internal chemical energy of the battery, achieving efficient explosion-proof and reignition-proof control of battery thermal runaway.

[0079] This invention aims to protect an immersion energy storage battery pack and its temperature control method. The liquid level adjustment mechanism within the battery pack achieves self-balancing of the immersion liquid level by adjusting the outflow at different liquid heights. The spray mechanism adjusts the spray volume in each area by replacing variable-diameter spray pipes at different positions to achieve uniform spraying. Simultaneously, continuous spraying is achieved under the coordinated control of the management and control module and the heat exchange device. When battery thermal runaway occurs, the battery pack can automatically activate a fire-fighting mode, switching seamlessly from normal operation mode to fire-fighting mode, achieving rapid and spontaneous battery pack safety protection. Furthermore, the invention's unique fluid microchannel and battery module spray surface design, which works in conjunction with the fluid microchannel, enable the battery module to achieve high thermal conductivity with the shortest distance in the vertical direction of battery module stacking, while utilizing flame-retardant, low thermal conductivity materials to achieve high thermal resistance in the direction of dense cell stacking. High thermal conductivity improves the thermal management efficiency of the battery module, promotes temperature uniformity, and high thermal resistance prevents mutual interference caused by heat generation between cells, while also enhancing the battery module's ability to prevent the spread of thermal runaway, thereby improving the overall safety of the battery module.

[0080] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects. For example, A and / or B indicates that there can be three relationships: A alone, A and B simultaneously, and B alone. Another example is A and / or B and / or C, which indicates that there can be eight relationships: A alone, B alone, C alone, A and B simultaneously, A and C simultaneously, B and C simultaneously, A, B, and C simultaneously, and A, B, and C simultaneously not existing. Furthermore, the character " / " in this article indicates that the preceding and following related objects have an "or" relationship.

[0081] In the embodiments of this application, "multiple" refers to two or more items, and "more than" refers to two or more items.

[0082] It should be noted that the sequence number of each step in this embodiment does not represent a limitation on the execution order of each step.

[0083] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A submersible energy storage battery pack, characterized in that, include: A battery module consists of one or more battery modules (1); Battery pack housing (2) for accommodating the battery module; The liquid outlet (3) and the liquid inlet (8) are both located on the battery pack housing (2) and are used for the outflow and inflow of the immersion liquid, respectively. The liquid level adjustment mechanism (4) is located inside the battery pack housing (2) and close to the liquid outlet (3). It has multiple liquid level adjustment holes (43, 44, 45) that communicate with the liquid outlet (3), and controls the liquid level in the battery pack housing (2) to be kept within a predetermined range by automatically adjusting the outflow of the immersion liquid. A spraying mechanism (9) is installed inside the battery pack housing (2) and located above the battery module for spraying the immersion liquid. The management and control module (7) is electrically connected to the battery module (1), the liquid level adjustment mechanism (4) and the spray mechanism (9), and is used to monitor the temperature and status information of the battery module (1), and control the liquid level adjustment mechanism (4) and the spray mechanism (9) according to the preset temperature control strategy. The liquid level regulating mechanism (4) includes: A blocking module (37) is disposed above the liquid outlet (3) and blocks the liquid outlet (3) according to the instructions of the management and control module (7); and Liquid level adjustment module (33), the liquid level adjustment holes (43, 44, 45) are opened on the liquid level adjustment module (33), the liquid level adjustment module (33) and the side of the battery pack box (2) form a hollow enclosure structure, which is used to separate the liquid outlet (3) and the immersion liquid in the battery pack box (2); The blocking module (37) further includes: The slider (31) and the slider push rod (32) are connected. The slider (31) is connected to the slider push rod (32). The slider push rod (32) can drive the slider (31) to block the liquid outlet (3).

2. The submersible energy storage battery pack according to claim 1, wherein, The spraying mechanism (9) further includes: The main sprinkler pipe (25) has multiple through holes; One or more variable diameter spray pipes (26) are installed at through holes on the main spray pipe (25) and communicate with the main spray pipe (25) for spraying the immersion liquid.

3. The submersible energy storage battery pack according to claim 2, wherein, The variable diameter spray pipe (26) has multiple holes (30) for spraying the immersion liquid.

4. The submersible energy storage battery pack according to claim 3, wherein, The variable diameter spray pipe (26) is detachable, allowing for the replacement of variable diameter spray pipes (26) with different diameters and hole sizes to adjust the spray volume in each area.

5. The submersible energy storage battery pack according to claim 2, wherein, The spraying mechanism (9) includes: a series spraying structure (91) and / or a parallel spraying structure (92). The series-connected spray structure (91) includes a spray inlet connector (22), an inlet adapter (23), an adapter (24), the main spray pipe (25), and the variable diameter spray pipe (26) connected in sequence. The parallel spray structure (92) includes a spray inlet connector (22), an inlet transfer pipe (23), and multiple series spray structures (91) connected in sequence.

6. The submersible energy storage battery pack according to claim 5, characterized in that, The spray inlet connector (22) is connected to the inlet (8) to receive the immersion liquid flowing in. One end of the inlet adapter (23) is connected to the spray inlet connector (22), and the other end is connected to the adapter (24). The other end of the adapter (24) is connected to the spray main pipe (25).

7. The submersible energy storage battery pack according to claim 1, wherein, The battery module (1) further includes: Multiple battery cells (20) are stacked laterally along a direction perpendicular to the largest surface of the battery cell (20), with gaps reserved between adjacent battery cells (20) and placed in sequence; Fluid microchannels (15) are formed in the direction perpendicular to the lateral stacking direction of the plurality of cells (20).

8. The submersible energy storage battery pack according to claim 7, characterized in that, The spraying surface of the spraying mechanism (9) is positioned above the fluid microchannel (15), so that the immersion liquid passes through the fluid microchannel (15) and the corresponding surface of the battery cell (20) under the action of spraying pressure and its own gravity.

9. The submersible energy storage battery pack according to claim 7, characterized in that, The battery module (1) further includes: A flame-retardant, low thermal conductivity material (19) is disposed on at least one side surface of the plurality of cells (20) along the stacking direction of the cells (20) to delay or block heat transfer between adjacent cells (20).

10. The submersible energy storage battery pack according to claim 9, characterized in that, The battery module (1) further includes: Thermosetting material (18) is disposed in the gap reserved between the adjacent cells (20) to support the battery module (1) and suppress heat spread when the battery module (1) is stacked. The fluid microchannel (15) is formed within the area enclosed by the flame-retardant low thermal conductivity material (19) and the thermosetting material (18).

11. The submersible energy storage battery pack according to any one of claims 7 to 10, further comprising: The storage tank (10) receives and stores the immersion liquid flowing out from the outlet (3); A pump (11) is connected to the storage tank (10) for conveying the immersion liquid; The heat exchange device (12) receives the immersion liquid delivered from the pump (11) and regulates the temperature of the immersion liquid. It is electrically connected to the management and control module (7). The heat exchange device (12) includes three working modes: cooling, preheating, and energy-saving temperature equalization. The filter (13) is used to adsorb and filter impurities in the immersion liquid. One end is connected to the heat exchange device (12), and the other end is connected to the liquid inlet (8).

12. The submersible energy storage battery pack according to claim 11, wherein, Multiple submerged energy storage battery packs are connected in series and / or in parallel to form a battery cluster, which includes a battery management system that manages the management control module (7).

13. A temperature control method for an immersion energy storage battery pack, characterized in that, The submersible energy storage battery pack according to claim 11 or 12 includes the following steps: Step S1: Turn on the battery pack and the battery pack enters normal working mode. The slider (31) is in the initial position (34) of the slider. The immersion liquid circulates in the battery pack to continuously heat the battery module. In step S2, after the battery pack is turned on, the management and control module (7) monitors the temperature of the battery cell (20) and / or the temperature of the immersion liquid in real time; Step S3: When the management control module (7) detects that the temperature of the cell (20) rises abnormally and / or the temperature of the immersion liquid rises abnormally and exceeds the maximum value of the preset normal temperature, the management control module (7) controls the pump (11) to increase its power to increase the flow rate of the immersion liquid, thereby accelerating the heat exchange and temperature equalization of the immersion liquid on the battery module. Step S4: When the management control module (7) detects that the temperature of the cell (20) and / or the temperature of the immersion liquid is ≥ the phase change point temperature of the immersion liquid, the battery pack enters the fire protection working mode. The management control module (7) controls the slider (31) to slide down to the slider blocking position (35) to completely block the outlet (3). At the same time, it controls the pump (11) to increase the power again to increase the flow rate of the immersion liquid again until the immersion liquid completely submerges the battery module. During this process, part of the immersion liquid absorbs heat and vaporizes, and is discharged through the pressure relief valve on the top cover. Step S5: When the management control module (7) detects that the temperature of the battery cell (20) and / or the temperature of the immersion liquid has dropped to the minimum value of the preset normal temperature, the battery pack ends the fire protection working mode, the management control module (7) controls the slider (31) to return to the slider initial position (34), and the excess immersion liquid flows back from the outlet (3) to the storage tank (10) through the liquid level adjustment module (33).

14. The temperature control method for an immersed energy storage battery pack according to claim 13, wherein, Step S1 includes: Step S11: When the battery pack is turned on, the management control module (7) detects the internal environment of the battery pack housing (2) and the initial temperature of the battery cells (20) in the battery module; Step S12: Determine the working mode of the heat exchange device (12) under different preset temperature ranges based on the internal environment of the battery pack housing (2) and the initial temperature of the battery cells (20) in the battery module. The management and control module (7) shares the battery pack data in real time and provides it to the heat exchange device. When the heat exchange device (12) starts, it responds to the instructions of the management and control module, automatically enters the corresponding working mode, and reports its working mode to the management and control module. Step S13: Start the pump (11) and the heat exchange device (12). The immersion liquid flows from the storage tank (10) through the pump (11) through the battery pack housing (2) and the filter (13), and then enters the spray mechanism (9) through the inlet (8). The spray mechanism (9) sprays the immersion liquid onto the battery module. Under the spray pressure and its own gravity, the immersion liquid quickly passes through the fluid microchannel (15) and the surface of the cell (20) to achieve heat exchange on the battery module. After heat exchange, the immersion liquid collects at the bottom of the battery pack housing (2). After the liquid level adjustment mechanism (4) is adjusted and controlled, it flows back into the storage tank (10) through the outlet (3). When the battery pack is working, the immersion liquid repeatedly circulates through this process to achieve continuous heat exchange or temperature equalization of the battery module. Step S14: After the battery pack is in operation, the management and control module (7) monitors the internal environment of the battery pack housing (2) and the temperature of the battery cells (20) in the battery module in real time. Step S15: Determine the working mode of the heat exchange device (12) under different preset temperature ranges based on the internal environment of the battery pack housing (2) and the temperature of the battery cell (20) in the battery module. The management control module (7) controls the heat exchange device (12) to switch between different working modes.

15. The temperature control method for an immersed energy storage battery pack according to claim 13, wherein, Step S4 further includes: when a portion of the battery cell (20) enters thermal runaway or thermal runaway propagates due to internal or external factors, the temperature of the battery cell (20) rises abnormally and is accompanied by an abnormal increase in internal pressure, the battery cell explosion-proof valve ruptures or the battery outer packaging is broken, the harmful gases and combustibles generated by the thermal runaway or thermal runaway propagation of the portion of the battery cell (20) are first diluted by the immersion liquid, and at the same time, the immersion liquid absorbs heat through phase change, converting the heat energy released by the battery thermal runaway into the heat of vaporization. After vaporization, the immersion liquid is discharged through the pressure relief valve on the top cover, and at the same time, the immersion liquid enters the interior of the portion of the battery cell (20) to dilute the electrolyte and block the electrochemical reaction.

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