Phase change immersed cooling energy storage system

Abstract

The invention discloses a phase change immersed cooling energy storage system which comprises an energy storage set and a cooling system. The energy storage group comprises a plurality of battery packs; the cooling system comprises a low-temperature cooling loop, a high-temperature cooling loop and condensing equipment, the low-temperature cooling loop adopts a circulating pump, and the high-temperature cooling loop adopts a compressor and a thermostatic expansion valve; and the condensing equipment cools the phase change cooling medium treated by the low-temperature cooling loop or the high-temperature cooling loop, and conveys condensed liquid back to the energy storage group. The battery cell is completely immersed by the cooling liquid, so that the temperatures of all parts of the battery cell tend to be consistent, and the influence on the battery cell performance due to overlarge temperature difference is avoided; the battery cell is rapidly cooled in a mode of heat absorption and gasification of the phase change cooling liquid, and the heat dissipation efficiency is higher than that of a traditional heat dissipation mode; two sets of cooling loops are adopted, the low-temperature cooling loop for pump-driven circulation is adopted at the low operating environment temperature, and the high-temperature cooling loop for compressor refrigeration is started at the high operating environment temperature, so that the overall service life of the system is prolonged, and the overall energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy batteries, and in particular to a phase-change immersion cooling energy storage system. Background Art

[0002] With the rapid development of the new energy industry, energy storage systems have been widely used in the fields of electricity, transportation, data centers, etc. However, during the operation of energy storage systems, safety accidents such as fire and explosion often occur, and the common cause of safety accidents is mainly battery thermal runaway.

[0003] Battery thermal runaway refers to the phenomenon that during the operation of the battery, the internal heat accumulation cannot be dissipated in time, causing the battery temperature to continue to rise, which in turn causes the internal chemical reaction of the battery to run out of control. Batteries have extremely strict requirements on operating temperature. When facing different application scenarios, their adaptability, safety, and stability have always been a concern for the outside world. In order to solve the problem of battery thermal runaway, the immersion liquid-cooled battery pack is an advanced battery thermal management technology that is widely used in fields that require efficient heat dissipation, such as electric vehicles and data centers.

[0004] The immersion liquid-cooled battery pack completely or partially immerses the battery module in a non-conductive coolant, and uses the coolant's efficient thermal conductivity to achieve efficient heat dissipation of the battery pack. Compared with traditional air cooling and indirect liquid cooling, this technology has advantages such as simple structure and rapid cooling, but it still has the following problems: the heat dissipation capacity is limited in high temperature environments, making it difficult to meet the efficient heat dissipation requirements of the battery pack, and the heat dissipation efficiency is still low; in order to improve the heat dissipation efficiency, the existing immersion liquid cooling system often needs to be equipped with high-power equipment, resulting in high overall power consumption. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a phase change immersion cooling energy storage system.

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended to be a general review, nor is it intended to identify key / important components or to delineate the scope of protection of these embodiments. Its only purpose is to present some concepts in a simple form as a preface to the detailed description that follows.

[0007] The present invention adopts the following technical solution:

[0008] The present invention provides a phase-change immersion cooling energy storage system, comprising: an energy storage group, a low-temperature cooling circuit, a high-temperature cooling circuit and a condensing device;

[0009] The low-temperature cooling circuit includes: a circulation pump for conveying the phase-changing cooling medium output by the energy storage group to the condensing device when the operating environment temperature is low;

[0010] The high-temperature cooling circuit includes: a compressor and a thermal expansion valve; the compressor is used to compress the phase-change cooling medium output by the energy storage group into high-temperature and high-pressure gas when the operating environment temperature is high; the thermal expansion valve is arranged on the output side of the compressor, and is used to reduce the high-temperature and high-pressure gas output by the compressor into high-temperature and low-pressure gas and transport it to the condensing equipment;

[0011] The condensing device is arranged at the output side of the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to exchange heat and cool the phase-change cooling medium processed by the low-temperature cooling circuit or the high-temperature cooling circuit with the outside air, and to transport the formed condensed liquid back to the energy storage group.

[0012] Furthermore, the phase change immersion cooling energy storage system also includes: a liquid storage tank for storing condensed liquid; the liquid storage tank is arranged between the condensing device and the energy storage group, the condensing device transports the formed condensed liquid to the liquid storage tank, and the liquid storage tank transports the condensed liquid back to the energy storage group.

[0013] Furthermore, the energy storage group includes: a plurality of battery packs; the battery pack includes: a battery pack case and battery cells located inside the battery pack case, a coolant is arranged in the battery pack case, and the battery cells are immersed in the coolant.

[0014] Furthermore, a certain space is reserved at the inner top of the battery pack case to form an internal cavity of the battery pack for accommodating the phase-change cooling medium.

[0015] Furthermore, the energy storage group also includes: a medium output pipeline and a medium return pipeline; the internal cavity of the battery pack is connected to the medium output pipeline through an output branch pipeline, and the phase change cooling medium is transported to the low-temperature cooling circuit or the high-temperature cooling circuit through the medium output pipeline; the battery pack case is connected to the medium return pipeline through an input branch pipeline, and the medium return pipeline is connected to the liquid storage tank.

[0016] Furthermore, the phase change immersion cooling energy storage system also includes: a solenoid valve; the solenoid valve is arranged at the connection position between the medium output pipeline and the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to distribute the phase change cooling medium output by the energy storage group to the low-temperature cooling circuit or the high-temperature cooling circuit.

[0017] Furthermore, the phase change immersion cooling energy storage system also includes: a temperature sensor and a control module, the temperature sensor is connected to the information input end of the control module, and the solenoid valve, the circulation pump and the compressor are connected to the control output end of the control module.

[0018] Furthermore, the low-temperature cooling circuit further includes: a first check valve; and the high-temperature cooling circuit further includes: a second check valve.

[0019] Furthermore, the condensing equipment includes: a cooling pipeline, a condenser and a condenser fan, the condenser is arranged on the cooling pipeline; the cooling pipeline is a copper tube or a stainless steel tube; the condenser is a tube-fin or plate-fin radiator; the condenser is made of copper or aluminum.

[0020] Furthermore, the coolant is an insulating liquid.

[0021] The beneficial effects brought by the present invention are:

[0022] 1. The battery cell is completely immersed in coolant. The good thermal conductivity of the coolant makes the temperature of the battery cell tend to be consistent, which avoids excessive temperature difference between the battery cells and affects the performance of the battery cell;

[0023] 2. The battery cells are quickly cooled by absorbing heat and vaporizing the phase change coolant that immerses the battery cells, which has higher heat dissipation efficiency than the traditional cold plate heat dissipation method;

[0024] 3. Two cooling circuits are used. A low-temperature cooling circuit with pump-driven circulation is used at lower operating ambient temperatures, and a high-temperature cooling circuit with compressor refrigeration is used at higher operating ambient temperatures. This makes the two cooling circuits more balanced, which not only improves the overall service life of the cooling system and adapts to different environmental conditions, but also reduces the overall energy consumption of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a schematic diagram of the system operation of the phase change immersion cooling energy storage system of the present invention;

[0027] Figure 2 It is a schematic diagram of the structure of a battery pack in the phase change immersion cooling energy storage system of the present invention;

[0028] Figure 3 It is a control principle diagram of the phase change immersion cooling energy storage system of the present invention. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be clear that the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] like Figure 1-3 As shown, in some illustrative embodiments, a phase change immersion cooling energy storage system is provided, including: an energy storage group, a cooling system, a solenoid valve 4 , a temperature sensor 31 and a control module 32 .

[0031] The cooling system adopts a two-stage cooling circuit, namely a low-temperature cooling circuit and a high-temperature cooling circuit, and the low-temperature cooling circuit and the high-temperature cooling circuit share a condensing device and a liquid storage tank 9.

[0032] The energy storage group includes: a medium output pipeline 21, a medium return pipeline 22 and a plurality of battery packs 1.

[0033] The battery pack 1 is responsible for storing and releasing electrical energy. It is a fully sealed structure and is designed to withstand a certain amount of internal or external pressure without leakage to ensure the safety and reliability of the system. The medium output pipeline 21 is a pipeline connecting the energy storage group and the cooling system, which is used to transfer the phase change cooling medium output by the battery pack 1 to the cooling system for heat dissipation. The medium return pipeline 22 transports the cooled medium back to the energy storage group to help maintain the operating temperature of the battery pack 1 within an ideal range, thereby improving the efficiency and life of the battery.

[0034] The battery pack 1 includes a battery pack case 14 and battery cells 13 .

[0035] The coolant 12 is arranged in the battery pack box 14. The coolant 12 is a liquid with a relatively low boiling point, so that it can be transformed into a gaseous state at a relatively low temperature, thereby taking away the heat generated by the battery cell 13, and is suitable for rapid cooling of high-density heat sources. At the same time, the coolant 12 is an insulating liquid, which has a high resistivity and will not cause a short circuit or other electrical failure even if the coolant contacts the battery assembly. In addition, the insulating liquid often has good thermal stability and chemical stability, and can maintain its physical and chemical properties unchanged over a wide temperature range.

[0036] The battery cell 13 is located inside the battery pack body 14 and is immersed in the coolant 12, ensuring that the heat generated by the battery cell 13 can be quickly absorbed by the coolant 12. The good thermal conductivity of the coolant 12 makes the temperature of each part of the battery cell 13 tend to be consistent, which avoids excessive temperature difference between the battery cells 13, thereby affecting the battery performance and avoiding local overheating.

[0037] Working principle: When the battery cell 13 generates a lot of heat, the coolant 12 in the battery pack box 14 will begin to boil due to the temperature rise and transform into a gaseous or gas-liquid mixed coolant, that is, a phase change cooling medium. This phase change process can absorb a lot of heat, thereby effectively reducing the temperature of the battery cell 13. Afterwards, the phase change cooling medium will be condensed back to liquid through the cooling system and re-injected into the battery pack box 14, forming a cycle. This cycle process can not only effectively improve the heat dissipation efficiency, but also keep the temperature of the battery cell 13 within a relatively stable range, thereby ensuring the battery life and system stability.

[0038] A certain space is reserved at the inner top of the battery pack case 14 to form an internal cavity 15 of the battery pack for accommodating the phase-change cooling medium, that is, a cavity is reserved at the top when the energy storage battery pack is pre-filled with coolant. The main function of the internal cavity 15 of the battery pack is to provide necessary space when the coolant 12 undergoes a phase change after being heated. The reserved cavity can be used as a pressure buffer. When the coolant 12 is heated and becomes a gas or a gas-liquid mixed state, it will occupy this part of the space, thereby reducing the pressure change caused by volume expansion.

[0039] The internal cavity 15 of the battery pack is connected to the medium output pipeline 21 through the output branch pipeline 23, so that the phase-change cooling medium in each internal cavity 15 of the battery pack converges to the medium output pipeline 21 through the output branch pipeline 23. The battery pack box 14 is connected to the medium return pipeline 22 through the input branch pipeline 24. The phase-change cooling medium is condensed back to liquid through the cooling system, and the liquid coolant is distributed to each battery pack box 14 through the medium return pipeline 22 and is recycled again.

[0040] The condensing equipment is used to condense the high-temperature cooling medium, usually the coolant in the form of steam, back to liquid for recycling, and specifically includes: cooling pipeline 25, condenser 5 and condenser fan 10, and condenser 5 is arranged on cooling pipeline 25. The cooling pipeline 25 is a key part connecting various components in the energy storage system, and is used to guide the cooling medium to circulate in the system. It is usually made of copper pipes or stainless steel pipes. Copper and stainless steel have good corrosion resistance and can maintain the integrity of the pipeline for a long time. It is suitable for a variety of cooling media.

[0041] The condenser 5 is a tube-fin radiator or a plate-fin radiator. The tube-fin radiator is composed of a series of tubes with fins. When the phase-change cooling medium passes through these tubes, the heat is transferred to the surrounding air through the fins, thereby condensing into a liquid state. The plate-fin radiator is composed of multiple layers of flat plates and fins. The phase-change cooling medium flows between the flat plates, and the heat is dissipated through the fins, which can also achieve the condensation effect. The condenser 5 is made of copper or aluminum. Copper has very good thermal conductivity and can quickly transfer heat from steam to the fins of the condenser. Although the thermal conductivity of aluminum is slightly inferior to that of copper, it is light in weight and low in cost, and is suitable for large-scale production.

[0042] The condenser fan 10 is used in conjunction with the condenser 5. Its main function is to promote the air flow around the condenser 5 and enhance the cooling effect. The airflow generated by the condenser fan 10 can help accelerate the heat loss and condense the phase-change cooling medium back to liquid faster. Working principle: When the phase-change cooling medium reaches the condenser 5 through the cooling pipeline 25, the internal structure of the condenser 5 transfers heat to the surrounding environment. At this time, the condenser fan 10 works to promote air flow and enhance the heat dissipation effect of the condenser 5. The phase-change cooling medium gradually cools and condenses into a liquid state, and then returns to other parts of the energy storage system through the cooling pipeline 25 and the medium return pipeline 22 for continued circulation.

[0043] The liquid storage tank 9 is used to store the condensed liquid output by the condenser 5. The medium return pipeline 22 is connected to the liquid storage tank 9, and the liquid storage tank 9 is arranged between the condenser 5 and the energy storage group. The condensing device transports the formed condensed liquid to the liquid storage tank 9, and the liquid storage tank 9 transports the condensed liquid back to the energy storage group. After the condenser 5 condenses the phase-change cooling medium into a liquid cooling medium, the liquid storage tank 9 can temporarily store the condensed liquid to ensure that the cooling medium in the system will not overflow or be lost. In addition, the liquid storage tank 9 plays a buffering role. It can provide a buffer zone between the supply and demand of the cooling medium. When the energy storage group needs more cooling medium, the liquid storage tank 9 can provide additional liquid; when the amount of steam generated by the energy storage group is large, the liquid storage tank 9 can temporarily store excess condensed liquid until it is returned to the energy storage group when needed.

[0044] The low-temperature cooling circuit is a pump-driven circuit, specifically including: a circulating pump 2 and a first check valve 7. The circulating pump 2 is used to transport the phase-change cooling medium output by the battery pack 1 to the condensing equipment for cooling treatment when the operating environment temperature is low. When the operating environment temperature is low, the battery cells 13 in the battery pack 1 are completely immersed in the coolant 12. During the charging and discharging process, the battery cells 13 generate heat, causing the coolant 12 that immerses the battery cells 13 to quickly absorb heat and vaporize, filling the internal cavity 15 of the battery pack. The gaseous or gas-liquid mixed coolant 12 after absorbing heat flows through the condenser 5 driven by the circulating pump 2, and after heat exchange and cooling with the outside air driven by the condenser fan 10, it condenses into liquid, enters the liquid storage tank 9, and is transported into the battery pack 1 through the medium return line 22.

[0045] The high-temperature cooling circuit is a compressor drive circuit, specifically including: a compressor 3, a thermal expansion valve 6 and a second check valve 8. The compressor 3 is used to compress the phase-change cooling medium output by the energy storage group into a high-temperature and high-pressure gas when the operating environment temperature is high. Here, high temperature means a higher temperature than the gas in the internal cavity 15 of the battery pack. The thermal expansion valve 6 is arranged on the output side of the compressor 3, and is used to reduce the high-temperature and high-pressure gas output by the compressor 3 into a high-temperature and low-pressure gas and transport it to the condensing equipment.

[0046] When the operating environment temperature is high, the battery cells 13 in the battery pack 1 are completely immersed in the coolant 12. During the charging and discharging process, the battery cells 13 generate heat, causing the coolant 12 that immerses the battery cells 13 to quickly absorb heat and vaporize, filling the internal cavity 15 of the battery pack. The gaseous or gas-liquid mixed coolant 12 after absorbing heat flows through the high-temperature cooling circuit under the control of the solenoid valve 4, and forms a high-temperature and high-pressure gas under the drive of the compressor 3. It flows through the thermal expansion valve 6 to form a high-temperature and low-pressure gas, flows through the condenser 5, and is driven by the condenser fan 10 to exchange heat with the outside air and cool it, and then condenses into liquid, enters the liquid storage tank 9, and is transported into the battery pack 1 through the medium return pipeline 22.

[0047] The condensing device is arranged at the output side of the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to exchange heat and cool the phase-change cooling medium processed by the low-temperature cooling circuit or the high-temperature cooling circuit with the outside air, and to transport the formed condensed liquid back to the energy storage group. In this process, the phase-change cooling medium is transported to the low-temperature cooling circuit or the high-temperature cooling circuit through the medium output pipeline 21; the solenoid valve 4 is arranged at the connection position between the medium output pipeline 21 and the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to distribute the phase-change cooling medium output by the energy storage group to the low-temperature cooling circuit or the high-temperature cooling circuit. The two cooling circuits of the cooling system control the flow direction through the solenoid valve 4, and can control whether the phase-change cooling medium output from the energy storage group flows to the low-temperature cooling circuit or the high-temperature cooling circuit according to the needs of the system, so as to realize automatic switching.

[0048] The temperature sensor 31 is connected to the information input end of the control module 32, and the solenoid valve 4, the circulating pump 2 and the compressor 3 are connected to the control output end of the control module 32. The temperature sensor 31 is used to monitor the temperature of the cooling medium, the battery pack and the environment in real time, and transmit the collected data to the control module 32 for analysis and processing. The control module 32 collects and processes the data from the temperature sensor 31, sends corresponding control signals to the solenoid valve 4, the circulating pump 2 and the compressor 3 according to the current temperature conditions and the set temperature threshold, and adjusts the working state of the system according to the preset algorithm or logic rules to ensure that the system operates in the best state.

[0049] When the system detects that the temperature changes and reaches the set threshold, it can automatically switch the flow direction of the cooling medium by controlling the solenoid valve 4, select a more suitable cooling path, and accurately control the flow direction of the cooling medium to ensure that the system meets the cooling requirements while achieving the best energy efficiency ratio. Intelligently controlling the flow direction of the cooling medium helps optimize the thermal management of the entire system, ensuring that the battery pack operates within the most suitable temperature range, thereby improving the performance and life of the battery.

[0050] In the phase change immersion cooling energy storage system of the present application, the coolant 12 completely immerses the battery cell 13, thereby ensuring the consistency of the temperature of each part of the battery cell 13 and achieving uniform temperature distribution. The heat generated by the battery cell 13 can be effectively evenly distributed, thereby minimizing the temperature difference between each battery cell 13, thereby avoiding the degradation of battery cell performance due to local overheating.

[0051] The phase change immersion cooling energy storage system of the present application realizes efficient heat dissipation, that is, the phase change coolant will vaporize after absorbing the heat generated by the battery cell and take away a large amount of heat to achieve rapid cooling. Compared with the traditional cold plate heat dissipation method, the present application has obvious advantages in heat dissipation efficiency.

[0052] This application adopts a dual cooling circuit design: one is a pump-driven circulation system used when the ambient temperature is low, and the other is a compressor refrigeration system enabled when the ambient temperature is high. This enables the system to select the most suitable cooling method under different environmental conditions, thereby reducing the working time of the compressor and extending the life of the equipment. At the same time, by reducing the working time of the compressor, the durability of the entire cooling system can be improved, which helps to reduce maintenance costs and ensure the long-term stable operation of the system.

[0053] In addition, since the system prioritizes the use of the pump-driven circulation system at lower ambient temperatures and activates compressor cooling at higher ambient temperatures, the overall power consumption of the energy storage system is reduced, which not only improves the energy efficiency of the system, but also meets the goal of energy conservation and emission reduction.

[0054] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A phase change immersion cooling energy storage system, characterized in that: include: Energy storage group, low temperature cooling circuit, high temperature cooling circuit and condensing equipment; The low-temperature cooling circuit includes: a circulation pump for conveying the phase-changing cooling medium output by the energy storage group to the condensing device when the operating environment temperature is low; The high-temperature cooling circuit includes: a compressor and a thermal expansion valve; the compressor is used to compress the phase-change cooling medium output by the energy storage group into high-temperature and high-pressure gas when the operating environment temperature is high; the thermal expansion valve is arranged on the output side of the compressor, and is used to reduce the high-temperature and high-pressure gas output by the compressor into high-temperature and low-pressure gas and transport it to the condensing equipment; The condensing device is arranged at the output side of the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to exchange heat and cool the phase-change cooling medium processed by the low-temperature cooling circuit or the high-temperature cooling circuit with the outside air, and to transport the formed condensed liquid back to the energy storage group.

2. A phase change immersion cooling energy storage system according to claim 1, characterized in that: Also includes: A liquid storage tank for storing condensed liquid; the liquid storage tank is arranged between the condensing device and the energy storage group, the condensing device transports the formed condensed liquid to the liquid storage tank, and the liquid storage tank transports the condensed liquid back to the energy storage group.

3. A phase change immersion cooling energy storage system according to claim 2, characterized in that: The energy storage group includes: a plurality of battery packs; the battery pack includes: a battery pack case and battery cells located inside the battery pack case, a coolant is arranged in the battery pack case, and the battery cells are immersed in the coolant.

4. A phase change immersion cooling energy storage system according to claim 3, characterized in that: A certain space is reserved at the inner top of the battery pack case to form an internal cavity of the battery pack for accommodating the phase-change cooling medium.

5. A phase change immersion cooling energy storage system according to claim 4, characterized in that: The energy storage group also includes: a medium output pipeline and a medium return pipeline; the internal cavity of the battery pack is connected to the medium output pipeline through an output branch pipeline, and the phase change cooling medium is transported to the low-temperature cooling circuit or the high-temperature cooling circuit through the medium output pipeline; the battery pack case is connected to the medium return pipeline through an input branch pipeline, and the medium return pipeline is connected to the liquid storage tank.

6. A phase change immersion cooling energy storage system according to claim 5, characterized in that: Also includes: Solenoid valve; The solenoid valve is arranged at the connection position between the medium output pipeline and the low-temperature cooling circuit and the high-temperature cooling circuit, and is used to distribute the phase-change cooling medium output by the energy storage group to the low-temperature cooling circuit or the high-temperature cooling circuit.

7. A phase change immersion cooling energy storage system according to claim 6, characterized in that: Also includes: A temperature sensor and a control module, wherein the temperature sensor is connected to an information input end of the control module, and the solenoid valve, the circulation pump and the compressor are connected to a control output end of the control module.

8. A phase change immersion cooling energy storage system according to claim 7, characterized in that: The low-temperature cooling circuit further includes: a first check valve; the high-temperature cooling circuit further includes: a second check valve.

9. A phase change immersion cooling energy storage system according to claim 8, characterized in that: The condensing equipment comprises: a cooling pipeline, a condenser and a condenser fan, wherein the condenser is arranged on the cooling pipeline; the cooling pipeline is a copper tube or a stainless steel tube; the condenser is a tube-fin type or plate-fin type radiator; the condenser is made of copper or aluminum.

10. A phase change immersion cooling energy storage system according to claim 9, characterized in that: The coolant is an insulating liquid.

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