Modular phase change cooling system, energy storage equipment and thermal management method

Abstract

The invention discloses a modular phase change cooling system, energy storage equipment and a thermal management method, and relates to the technical field of electrochemical energy storage thermal management. The steam outlets of all the battery pack modules are connected to the inlet of the condensing device in parallel through the gas-phase parallel loop; and the liquid-phase series passive overflow loop is used for sequentially connecting the liquid inlets and the liquid outlets of the battery pack modules in series. According to the modularized phase change cooling system, the liquid phase series overflow design is adopted, liquid levels in all the independent modules can be automatically and synchronously kept consistent without any sensor, controller or actuator, the structure is simple, and the reliability is high. The design of gas-phase parallel connection and liquid-phase series connection enables the steam outlet pressure of each battery pack module to be balanced, a consistent efficient phase change heat dissipation environment is provided for all battery cells, meanwhile, the requirement for a large active control component is eliminated, the volume energy density of the whole battery cluster is remarkably improved, and the occupied area of equipment is reduced.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage thermal management technology, and in particular to a modular phase change cooling system, energy storage device and thermal management method. Background Technology

[0002] With the large-scale application of electrochemical energy storage, represented by lithium-ion batteries, in power systems, the performance, reliability, and maintainability of their thermal management systems have become key challenges. Batteries generate heat during operation. Uneven or inefficient heat dissipation will lead to increased battery temperature and excessive temperature differences, thereby accelerating aging, shortening lifespan, and even causing safety accidents such as thermal runaway.

[0003] Currently, the mainstream air-cooling solution has a simple structure but poor temperature uniformity and limited heat dissipation capacity; liquid-cooling solution has strong heat dissipation capacity, but has inherent defects such as complex piping, high risk of leakage, uneven distribution of coolant and difficult maintenance (often requiring the entire system to be drained).

[0004] Phase change cooling technology utilizes the latent heat of vaporization of the working fluid to absorb heat, which theoretically can achieve extremely high heat dissipation efficiency and excellent temperature uniformity. However, it faces severe challenges when applied to energy storage systems composed of multiple modules: 1. The system is usually strongly coupled, making it difficult to isolate faults, requiring a complete shutdown for maintenance, resulting in low availability; 2. The distribution and control of gas and liquid two-phase flow between multiple modules is extremely complex, often relying on expensive active control systems (such as pumps, valves, sensor arrays, etc.), which are costly and reduce reliability.

[0005] Therefore, existing technologies still have shortcomings and deficiencies, and there is an urgent need in this field for an innovative thermal management architecture to simultaneously meet the energy storage system’s requirements for high heat dissipation performance, high operational reliability and high ease of maintenance. Summary of the Invention

[0006] The purpose of this invention is to provide a modular phase change cooling system, energy storage device and thermal management method, which solves the technical problems of many defects in existing air cooling schemes, liquid cooling schemes and phase change cooling technologies when applied to energy storage systems.

[0007] To achieve the above objectives, the present invention provides a modular phase change cooling system, comprising:

[0008] A plurality of independent battery pack modules, each battery pack module comprising: a sealed housing; a plurality of battery cells disposed within the sealed housing and an insulating liquid phase change working fluid immersed in at least the lower part of the battery cells; a vapor outlet provided in the sealed housing; and a liquid inlet and a liquid outlet provided in the sealed housing;

[0009] A gas-phase parallel circuit connects the vapor outlets of all the battery pack modules in parallel to the inlet of the condenser, so that the vapor outlets of each battery pack module are in a parallel connected state.

[0010] A liquid-phase series passive overflow circuit connects the liquid inlet and liquid outlet of each of the battery pack modules in series and connects them to the outlet of the condensation device.

[0011] The positions of the liquid inlet and outlet are configured such that when the liquid level inside one of the battery pack modules reaches a predetermined height, the liquid can flow out from the liquid outlet of the battery pack module and enter the liquid inlet of the next battery pack module, thereby achieving passive overflow balance of the liquid levels in all the battery pack modules.

[0012] In some technical solutions, the liquid inlet and the liquid outlet are located at the same height.

[0013] In some technical solutions, each battery pack module has a gas collection chamber at the top inner part of its sealed housing, which is connected to the steam outlet. The bottom of the gas collection chamber is provided with a partition, which has a through hole for steam to pass through.

[0014] In some technical solutions, the steam outlet is located at the top center of the sealed housing.

[0015] In some technical solutions, several of the battery pack modules are arranged along the height direction.

[0016] In some technical solutions, the gas-phase parallel loop includes a common steam main and multiple steam connection branches, each of the steam connection branches connecting a steam outlet of one of the battery pack modules to the common steam main, and the common steam main connecting to the inlet of the condenser.

[0017] In some technical solutions, the liquid-phase series passive overflow circuit includes a main reflux pipe and multiple external series connection pipes. The main reflux pipe connects the outlet of the condenser to the liquid inlet of the uppermost battery pack module. The external series connection pipes are used to connect the liquid outlet of the previous battery pack module to the liquid inlet of the next battery pack module.

[0018] In some technical solutions, a first valve is provided at the steam outlet, and a second valve is provided at the liquid inlet and the liquid outlet.

[0019] The present invention also provides an energy storage device, including the modular phase change cooling system provided by any of the above technical solutions.

[0020] The present invention also provides a thermal management method, applied to the modular phase change cooling system provided by any of the above technical solutions, comprising:

[0021] Insulating liquid phase change working fluid is injected into the liquid-phase series passive overflow circuit until the liquid level in all battery pack modules reaches the preset height.

[0022] The cells in each battery pack module generate heat, causing the insulating liquid phase change working fluid to vaporize. The vapor is collected in the gas phase parallel circuit and condensed into liquid by the condensation device. The condensate returns to the liquid phase series passive overflow circuit, so that the liquid level in all battery pack modules is in passive overflow balance.

[0023] Compared with the aforementioned background technology, the modular phase change cooling system provided by the present invention has at least the following beneficial effects:

[0024] The liquid phase series overflow design can automatically and synchronously maintain an absolutely consistent liquid level in all independent modules without the need for any sensors, controllers or actuators. It has a simple structure and high reliability.

[0025] The design of parallel gas phase and series liquid phase ensures that the vapor outlet pressure of each battery pack module is balanced, avoiding the problems of pressure drop accumulation and uneven heat dissipation caused by series connection. It provides a consistent and efficient phase change heat dissipation environment for all cells, while eliminating the need for large active control components. This significantly improves the volumetric energy density of the entire battery pack and helps to reduce the equipment footprint.

[0026] Each battery pack module is an independent sealed unit with an independent modular design, eliminating the need for traditional complex external liquid cooling networks and distributors. This significantly reduces manufacturing costs while improving reliability, and enables hot-swappable replacement without shutting down the system, greatly improving system availability and operational economy.

[0027] The energy storage device provided by this invention includes the aforementioned modular phase change cooling system and has the same beneficial effects. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the modular phase change cooling system provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of a single battery pack module provided in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of the partition provided in an embodiment of the present invention.

[0032] Figures 1 to 3Chinese figure labels: 1. Battery cell; 2. Sealed outer shell; 3. Insulating liquid phase change working fluid; 4. Gas collection chamber; 5. Baffle plate; 6. Steam outlet; 7. Steam connection branch pipe; 8. Common steam main pipe; 9. Condensation device; 10. Main return pipe; 11. Liquid inlet; 12. Liquid outlet; 13. External series connection pipe; 14. Cabinet; 15. Preset liquid level line; 16. Through hole. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Please refer to this as well. Figures 1 to 3 This invention provides a modular phase change cooling system, which includes:

[0036] A plurality of independent battery pack modules, each battery pack module including: a sealed housing 2; a plurality of battery cells 1 disposed within the sealed housing 2 and an insulating liquid phase change working medium 3 immersed in at least the lower part of the battery cells 1; a vapor outlet 6 opened in the sealed housing 2; and a liquid inlet 11 and a liquid outlet 12 opened in the sealed housing 2.

[0037] The gas-phase parallel circuit connects the vapor outlets 6 of all battery pack modules in parallel to the inlet of the condenser 9, so that the vapor outlets 6 of each battery pack module are in a parallel connected state.

[0038] The liquid-phase series passive overflow circuit connects the liquid inlet 11 and liquid outlet 12 of each battery pack module in series and connects them to the outlet of the condenser 9.

[0039] The positions of the inlet 11 and outlet 12 are configured such that when the liquid level inside one of the battery pack modules reaches a predetermined height, the liquid can flow out from the outlet 12 of the battery pack module and enter the inlet 11 of the next battery pack module, thereby achieving passive overflow balance of the liquid level in all battery pack modules.

[0040] Each battery pack module is an independent sealed unit, encapsulating multiple battery cells 1 and a certain amount of insulating liquid phase change working fluid 3 within a sealed housing 2. The multiple battery cells 1 can be arranged at equal intervals within the sealed housing 2. A vapor outlet 6 is provided on the upper side wall of the sealed housing 2, and a liquid inlet 11 and a liquid outlet 12 are provided on the front or lower side of the sealed housing 2. All vapor outlets 6 are connected in parallel through a gas-phase parallel circuit, ultimately connecting to the inlet of a condensing device 9 (such as an air-cooled or water-cooled condenser). All battery pack modules are connected in series through their liquid inlets 11 and outlets 12 via a liquid-phase series passive overflow circuit, and connected to the outlet of the condensing device 9.

[0041] When the insulating liquid phase change working fluid 3 is filled, the liquid flows from the condenser 9 into the first battery pack module through the liquid phase series passive overflow circuit. When the liquid level in this module rises to the height of its outlet 12, because the inlet 11 and outlet 12 are connected, the continuing to flow in liquid cannot raise the liquid level in this module, and it will overflow from the outlet 12 into the inlet 11 of the next battery pack module. This process is chained until the liquid level in all battery pack modules reaches the equilibrium position determined by the height of their respective outlets 12.

[0042] The modular phase change cooling system provided by this invention adopts a liquid-phase series overflow design, which can automatically and synchronously maintain an absolutely consistent liquid level in all independent modules without any sensors, controllers, or actuators. It features a simple structure and high reliability. The parallel gas-phase and series liquid-phase design ensures balanced pressure at the vapor outlet 6 of each battery pack module, avoiding the pressure drop accumulation and uneven heat dissipation problems caused by series connection. This provides a consistent and efficient phase change cooling environment for all cells 1, while eliminating the need for large active control components, significantly improving the volumetric energy density of the entire battery cluster, and reducing the equipment footprint. Each battery pack module is an independent sealed unit with an independent modular design, eliminating the need for traditional complex external liquid cooling pipe networks and distributors. This significantly reduces manufacturing costs while improving reliability, and enables hot-swappable replacement without system shutdown, greatly improving system availability and operational economy.

[0043] In addition, the modular phase change cooling system also includes a cabinet 14, on which all battery pack modules, gas phase parallel circuits and liquid phase series passive overflow circuits are fixedly installed.

[0044] In some embodiments, the inlet 11 and the outlet 12 are located at the same height.

[0045] Please refer to this as well. Figures 1 to 2As a reliable way to achieve the aforementioned passive overflow balance, the inlet 11 and outlet 12 are located at the same height, which is the preset liquid level line 15. The inlet 11 and outlet 12 are usually located at the lower part of the sealed housing 2, but higher than the bottom of the battery cell 1, and their center lines or upper edges are aligned on the same horizontal line.

[0046] By setting the inlet 11 and outlet 12 at the same height, when the liquid level in the battery pack module touches the preset liquid level line 15, the hydrostatic pressure of the fluid at the inlet 11 and outlet 12 is equal. The liquid will choose the path of least resistance and flow out from the outlet 12, thereby reliably triggering overflow and ensuring the stability and repeatability of the liquid level balance.

[0047] In some embodiments, the top inner part of the sealed housing 2 of each battery pack module is provided with a gas collecting chamber 4, which is connected to a steam outlet 6. The bottom of the gas collecting chamber 4 is provided with a partition 5, which is provided with a through hole 16 for steam to pass through.

[0048] Please refer to this as well. Figures 1 to 3 Inside each battery pack module, a gas collecting chamber 4 is provided at the top inner part of its sealed outer shell 2. The gas collecting chamber 4 is a cavity located above the battery cell 1 and is connected to the vapor outlet 6. The bottom of the gas collecting chamber 4 is formed by a partition 5, which separates the gas collecting chamber 4 from the battery cell 1 and the liquid phase space below. The partition 5 has multiple through holes 16, which can be a uniformly distributed array of circular holes, a grid, or other porous structures.

[0049] The heat generated by cell 1 causes the working fluid to boil and produce steam. The steam rises and passes through the through-hole 16 on the separator 5 into the gas collecting chamber 4, where it is collected. After the steam pressure becomes uniform within the gas collecting chamber 4, it is discharged from the steam outlet 6. The gas collecting chamber 4 plays a role in equalizing pressure, effectively suppressing minor fluctuations in steam pressure from different locations of cell 1, ensuring a uniform steam environment inside the battery pack module, thereby improving temperature uniformity. Moreover, while allowing steam to pass smoothly, the separator 5 and its through-hole 16 effectively prevent large droplets that may be generated during boiling from splashing directly into the pipe at the steam outlet 6, thus playing a preliminary role in gas-liquid separation and improving the system's operational stability.

[0050] With this configuration, each independent battery pack module forms a closed phase change unit. The working fluid boils on the surface of the cell 1 and condenses on the wall of the top gas collecting cavity 4, which is very similar to the principle of a heat pipe. Combined with the pressure equalization effect of the internal gas collecting cavity 4, excellent temperature uniformity is achieved inside each battery pack module.

[0051] In some embodiments, the steam outlet 6 is located at the top center of the sealed housing 2.

[0052] Please refer to this as well. Figures 1 to 2Steam outlet 6 is located at the center of the top plate of the gas collecting chamber 4. By placing steam outlet 6 at the top center, steam from all parts of the gas collecting chamber 4 can be collected and discharged along the shortest and most balanced path, minimizing local resistance to steam flow and helping to maintain the consistency of steam pressure between modules in the entire module and even in parallel circuits.

[0053] In some embodiments, a plurality of battery pack modules are arranged along the height direction.

[0054] Please refer to this as well. Figures 1 to 2 Several battery pack modules are arranged along the height direction (vertical direction), resulting in a compact layout and saving floor space.

[0055] In some embodiments, the gas-phase parallel loop includes a common steam main 8 and a plurality of steam connection branches 7, each steam connection branch 7 connecting a battery pack module’s steam outlet 6 to the common steam main 8, the common steam main 8 being connected to the inlet of the condenser 9.

[0056] Please refer to this as well. Figures 1 to 2 The parallel vapor phase loop includes a common steam header 8 and multiple steam connection branches 7. The steam outlet 6 of each battery pack module is connected to the common steam header 8 via a steam connection branch 7, which in turn connects to the inlet of the condenser 9. This parallel connection ensures that all battery pack modules operate under the same steam back pressure, providing uniform external conditions for phase change boiling within each module and guaranteeing temperature consistency among the modules.

[0057] In some embodiments, the liquid-phase series passive overflow circuit includes a main return pipe 10 and a plurality of external series connection pipes 13. The main return pipe 10 connects the outlet of the condenser 9 to the liquid inlet 11 of the uppermost battery pack module. The external series connection pipes 13 are used to connect the liquid outlet 12 of the previous battery pack module to the liquid inlet 11 of the next battery pack module.

[0058] Please refer to this as well. Figures 1 to 2 The liquid-phase series passive overflow circuit includes a main return pipe 10 and multiple external series connection pipes 13. The main return pipe 10 extends from the outlet of the condenser 9 and connects to the liquid inlet 11 of the first battery pack module located at the top. Then, the liquid outlet 12 of the first battery pack module is connected to the liquid inlet 11 of the second battery pack module through an external series connection pipe 13, and so on in series. The liquid outlet 12 of the last battery pack module can be used as an observation port.

[0059] This configuration ensures that the overflow direction from top to bottom follows gravity, making the filling and balancing process smoother and faster.

[0060] In some embodiments, a first valve is provided at the steam outlet 6, and a second valve is provided at the liquid inlet 11 and the liquid outlet 12.

[0061] To enable independent maintenance of the battery pack module, a first valve is installed at the steam outlet 6, and second valves are installed at the liquid inlet 11 and the liquid outlet 12. The first valve can be installed on the steam connection branch pipe 7, near the steam outlet 6. The second valves are installed at the connection pipes of the liquid inlet 11 and the liquid outlet 12, respectively, or a quick-connect coupling integrating both valves can be used.

[0062] During normal operation, all valves are open. When a battery pack module needs replacement or maintenance, its first valve is closed to disconnect the gas phase circuit; the two second valves at its inlet 11 and outlet 12 are closed to disconnect the liquid phase circuit. At this time, the battery pack module is completely isolated from the system, the internal working fluid is sealed, and the rest of the system can continue to operate. Maintenance personnel can safely disconnect the pipeline connections and remove the battery pack module, enabling hot-swappable replacement without shutting down the system, greatly improving system availability and maintenance economy.

[0063] In addition to the modular phase change cooling system disclosed in the above embodiments, the present invention also provides an energy storage device including the above-described modular phase change cooling system.

[0064] In addition to the modular phase change cooling systems disclosed in the above embodiments, the present invention also provides a thermal management method applied to the modular phase change cooling system provided in any of the above embodiments, comprising:

[0065] Insulating liquid phase change working fluid 3 is injected into the liquid phase series passive overflow circuit until the liquid level in all battery pack modules reaches the preset height.

[0066] The cells 1 in each battery pack module generate heat, causing the insulating liquid phase change working medium 3 to vaporize. The vapor is collected in the condensation device 9 through the gas phase parallel circuit and condensed into liquid. The condensate returns to the liquid phase series passive overflow circuit, so that the liquid level in all battery pack modules is in passive overflow balance.

[0067] Specifically, before the modular phase change cooling system is first put into operation, a precisely calculated amount of insulating liquid phase change working fluid 3 is introduced into the system through the main return pipe 10. The insulating liquid phase change working fluid 3 enters the first battery pack module. When the liquid level in this module rises to the preset liquid level line 15, the excess liquid overflows through the liquid outlet 12 to the next module, until the liquid level in all battery pack modules reaches the preset liquid level line 15, and the system enters liquid phase static equilibrium.

[0068] When the battery is working, the heat generated by the cells 1 in each battery pack module is absorbed and vaporized by the working fluid. The vapor is collected in the condensation device 9 through the gas phase parallel loop, where it condenses and releases heat. The condensate returns to the system through the main return pipe 10 and is continuously replenished to each battery pack module through the series passive overflow loop to maintain dynamic liquid level balance and circulation.

[0069] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0070] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A modular phase change cooling system, characterized in that, include: A plurality of independent battery pack modules, each battery pack module comprising: a sealed housing (2); a plurality of battery cells (1) disposed within the sealed housing (2) and an insulating liquid phase change working medium (3) immersed in at least the lower part of the battery cells (1); a vapor outlet (6) provided in the sealed housing (2); and a liquid inlet (11) and a liquid outlet (12) provided in the sealed housing (2); A gas-phase parallel circuit connects the vapor outlets (6) of all the battery pack modules in parallel to the inlet of the condenser (9) so that the vapor outlets (6) of each battery pack module are in a parallel connection state. The liquid-phase series passive overflow circuit connects the liquid inlet (11) and liquid outlet (12) of each of the battery pack modules in series and connects them to the outlet of the condenser (9). The positions of the liquid inlet (11) and liquid outlet (12) are configured such that when the liquid level inside one of the battery pack modules reaches a predetermined height, the liquid can flow out from the liquid outlet (12) of the battery pack module and enter the liquid inlet (11) of the next battery pack module, thereby achieving passive overflow balance of the liquid level in all the battery pack modules.

2. The modular phase change cooling system according to claim 1, characterized in that, The inlet (11) and the outlet (12) are located at the same height.

3. The modular phase change cooling system according to claim 1, characterized in that, Each of the battery pack modules has a gas collection chamber (4) at the top of its sealed housing (2), which is connected to the steam outlet (6). The bottom of the gas collection chamber (4) is provided with a partition (5), which has a through hole (16) for steam to pass through.

4. The modular phase change cooling system according to claim 3, characterized in that, The steam outlet (6) is located at the top center of the sealed housing (2).

5. The modular phase change cooling system according to any one of claims 1 to 4, characterized in that, Several of the battery pack modules are arranged along the height direction.

6. The modular phase change cooling system according to claim 5, characterized in that, The gas-phase parallel circuit includes a common steam main (8) and multiple steam connection branches (7), each of the steam connection branches (7) is connected to the steam outlet (6) of one of the battery pack modules and the common steam main (8), and the common steam main (8) is connected to the inlet of the condenser (9).

7. The modular phase change cooling system according to claim 5, characterized in that, The liquid-phase series passive overflow circuit includes a main return pipe (10) and multiple external series connection pipes (13). The main return pipe (10) connects the outlet of the condenser (9) to the liquid inlet (11) of the uppermost battery pack module. The external series connection pipes (13) are used to connect the liquid outlet (12) of the previous battery pack module to the liquid inlet (11) of the next battery pack module.

8. The modular phase change cooling system according to claim 1, characterized in that, A first valve is provided at the steam outlet (6), and a second valve is provided at the liquid inlet (11) and the liquid outlet (12).

9. An energy storage device, characterized in that, Includes the modular phase change cooling system according to any one of claims 1 to 8.

10. A thermal management method, characterized in that, The modular phase change cooling system according to any one of claims 1 to 8 comprises: Insulating liquid phase change working fluid (3) is injected into the liquid phase series passive overflow circuit until the liquid level in all battery pack modules reaches the preset height; The cells (1) in each battery pack module generate heat to vaporize the insulating liquid phase change working medium (3). The vapor is collected in the condensation device (9) through the gas phase parallel circuit and condensed into liquid. The condensate returns to the liquid phase series passive overflow circuit, so that the liquid level in all battery pack modules is in passive overflow balance.

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