An energy storage thermal management system based on an air-float centrifugal compressor

Abstract

The application discloses an energy storage thermal management system based on an air-floating centrifugal compressor, which comprises a refrigeration module, an intermediate heat exchanger and a cooling module. The refrigeration module is used for refrigerant circulation and comprises an air-floating centrifugal compressor for compressing refrigerant, a condenser for cooling compressed refrigerant and a throttling device for throttling and expanding the refrigerant after cooling. The intermediate heat exchanger comprises two inlets and two outlets, which are communicated with pipelines of the refrigeration module and the cooling module respectively, so that the refrigerant and the coolant realize heat exchange. The cooling module is used for coolant circulation to cool the energy storage device and comprises a water pump for providing power for the coolant circulation. By adopting the air-floating centrifugal compressor as the core component of the refrigeration module, the weight and volume of the thermal management system can be effectively reduced, and the reliability of the compressor and the system can be improved.

Description

Technical Field

[0001] This invention relates to the field of thermal management technology, and in particular to an energy storage thermal management system based on an air-float centrifugal compressor. Background Technology

[0002] Thermal management refers to the management and control of the temperature of the overall system, discrete components, or their environment, with the aim of maintaining the normal operation of each component or improving its performance or lifespan. Currently, thermal management is commonly required in fields such as electrochemical energy storage, and it has a significant impact on the performance, lifespan, and safety of energy storage systems. Because liquid-cooled thermal management systems have strong heat exchange capabilities, allowing cell temperature differences to be within 3°C, liquid cooling can significantly extend the lifespan of energy storage systems compared to air-cooled systems. Therefore, liquid-cooled systems are currently widely used in the energy storage field.

[0003] The cooling capacity required for energy storage liquid cooling systems is typically 100kW or less. Refrigeration cycles with such small cooling capacities often employ traditional scroll or rotary compressors, which have the following drawbacks:

[0004] The compressor assembly has a large volume, and some energy storage systems require two compressor refrigeration systems for cooling, which takes up a lot of space.

[0005] The internal parts of the compressor will rub against each other during operation. Therefore, the cleanliness requirements for other parts of the system are high, and the reliability of the system operation is poor.

[0006] To improve reliability, these compressors typically require compressor oil for lubrication and sealing. This increases the cost of compressor oil, and the oil may also mix with the refrigerant after entering the system, affecting the refrigerant's heat exchange and directly causing the system's cooling capacity to drop by more than 5%. Summary of the Invention

[0007] To address some or all of the problems in the prior art, this invention provides an energy storage thermal management system based on an air-float centrifugal compressor, comprising:

[0008] Refrigeration module, used for refrigerant circulation, includes:

[0009] An air-float centrifugal compressor is used to compress refrigerant to form refrigerant in its first state.

[0010] A condenser, its inlet connected to the exhaust port of the air-float centrifugal compressor, is used to cool the refrigerant in the first state to form a refrigerant in a second state, the second state having a lower temperature but the same pressure than the first state; and

[0011] A throttling device, connected to the outlet of the condenser, throttles the refrigerant in the second state, causing it to expand to the third state, where the pressure in the third state is lower than that in the second state, but the temperature is the same.

[0012] Intermediate heat exchanger, including:

[0013] A refrigerant pipeline includes a first inlet and a first outlet, the first inlet being connected to the outlet of the throttling device, and the first outlet being connected to the inlet of the air-float centrifugal compressor; and

[0014] A coolant piping system, disposed around the refrigerant piping system to allow heat exchange between coolants, and connected to the piping of the cooling module, includes a second inlet and a second outlet; and

[0015] A cooling module for coolant circulation to cool the energy storage device includes a water pump that powers the coolant circulation.

[0016] Furthermore, the energy storage thermal management system also includes at least one temperature sensor and at least one pressure sensor.

[0017] Furthermore, the temperature sensor is located at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air-float centrifugal compressor.

[0018] Furthermore, the pressure sensor is located at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air-float centrifugal compressor.

[0019] Furthermore, the energy storage thermal management system also includes a fan, which is located at the condenser, for introducing ambient temperature air into the condenser to achieve heat exchange.

[0020] Furthermore, the air-float centrifugal compressor includes:

[0021] An electric motor, comprising:

[0022] The shell has a first chamber and a second chamber at its two ends;

[0023] A rotor, on which an air-bearing radial bearing is mounted, and a thrust disk is mounted at the end of the rotor, with air-bearing thrust bearings mounted on one or both sides of the thrust disk; and

[0024] stator;

[0025] An impeller is arranged at the end of the rotor and located within the first chamber and / or the second chamber;

[0026] An air inlet, which is connected to the air inlet of the first chamber;

[0027] An exhaust port, which is connected to the exhaust port of the second chamber;

[0028] The connecting pipe has its two ends connected to the air outlet of the first chamber and the air inlet of the second chamber, respectively.

[0029] Furthermore, the air-float centrifugal compressor also includes an interstage air supply port, which is disposed on the connecting pipe.

[0030] Furthermore, the intermediate heat exchanger includes a plate heat exchanger.

[0031] Furthermore, the first inlet and the second outlet are disposed on the first side of the intermediate heat exchanger, and the second inlet and the first outlet are disposed on the second side of the intermediate heat exchanger opposite to the first side.

[0032] Furthermore, the energy storage thermal management system also includes a degassing and liquid replenishment module, comprising:

[0033] An expansion pot with a pressure relief valve on its lid;

[0034] The gas storage pipe is connected to the second inlet of the intermediate heat exchanger via a tee; and

[0035] The water supply pipe is connected to the inlet of the water pump via a tee.

[0036] This invention provides an energy storage thermal management system based on an air-floating centrifugal compressor. The air-floating centrifugal compressor is used as the core component of the refrigeration module. Compared to compressors in traditional energy storage thermal management systems, it eliminates the need for an oil return system, resulting in high compressor and system reliability. During operation, the bearings do not contact the motor shaft, leading to minimal bearing wear and a long lifespan. Furthermore, the air-floating centrifugal compressor boasts high power density while maintaining a small size and weight. The internal circulation dynamic pressure air-floating bearing eliminates the need for additional air supply lines, resulting in a simple and reliable structure. The intermediate air supply port facilitates interstage cooling, reducing compressor power consumption. The use of a closed impeller and sealing teeth on the inner wall of the compressor housing effectively reduces leakage and backflow losses, improving compressor aerodynamic efficiency. This energy storage thermal management system exhibits good cooling capacity and COP in the cooling of containerized electrochemical energy storage batteries. Attached Figure Description

[0037] To further illustrate the above and other advantages and features of the various embodiments of the present invention, a more specific description of the various embodiments of the present invention will be presented with reference to the accompanying drawings. It is to be understood that these drawings depict only typical embodiments of the invention and are therefore not intended to limit its scope. In the drawings, identical or corresponding parts will be indicated by identical or similar reference numerals for clarity.

[0038] Figure 1This diagram illustrates a structural schematic of an energy storage thermal management system based on an air-float centrifugal compressor, according to an embodiment of the present invention; and

[0039] Figures 2a-2e The diagram shows a structural schematic of an air-float centrifugal compressor in different embodiments of the present invention. Detailed Implementation

[0040] In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details. Furthermore, it should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale.

[0041] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0042] To address the shortcomings of existing energy storage thermal management products, this invention replaces traditional scroll or rotary compressors with a high-speed air-floating centrifugal compressor. The high-speed air-floating centrifugal compressor serves as the power source for the refrigerant circuit, forming an energy storage thermal management system. Due to the smaller size of the centrifugal compressor, for the same cooling capacity, the volume of a centrifugal compressor based on a high-speed permanent magnet synchronous motor is reduced by approximately 50%, and the weight by approximately 90%, compared to a scroll compressor. This allows for the placement of more energy storage batteries within a container of the same size. The high-speed air-floating centrifugal compressor uses air-floating bearings, eliminating the need for oil lubrication. During operation, the shaft does not contact the bearing; instead, the motor rotor is suspended by an air film, thus eliminating wear and increasing the system's lifespan by more than double, thereby improving the reliability of the compressor and the system. Furthermore, the air-floating bearings eliminate the need for compressor oil, increasing the system's cooling capacity and eliminating the need for oil return lines, reducing structural and compressor oil costs.

[0043] The present invention will be further described below with reference to the accompanying drawings of the embodiments.

[0044] Figure 1 This diagram illustrates a structural schematic of an energy storage thermal management system based on an air-float centrifugal compressor, according to an embodiment of the present invention. Figure 1As shown, an energy storage thermal management system based on an air-float centrifugal compressor includes a refrigeration module 001, an intermediate heat exchanger 002, and a cooling module 003. The refrigeration module 001 is used for refrigerant circulation to cool the coolant, and the cooling module 003 is used for coolant circulation to cool the energy storage device. The refrigeration module 001 and the cooling module 003 are coupled through the intermediate heat exchanger 002.

[0045] like Figure 1 As shown, the core component of the refrigeration module 001 is an air-float centrifugal compressor 011. The air inlet of the air-float centrifugal compressor 011 is connected to an intermediate heat exchanger 002. The high-temperature, low-pressure refrigerant, after heat exchange with the coolant in the intermediate heat exchanger, enters the air-float centrifugal compressor 011 for compression, forming a refrigerant in its first state. In one embodiment of the present invention, the air-float centrifugal compressor 011 includes a motor, an impeller, an air inlet, an exhaust outlet, and a connecting pipe. The motor includes a rotor system, a stator, and a housing.

[0046] Figures 2a-2e The diagram illustrates the structure of a centrifugal compressor with air flotation in different embodiments of the present invention. As shown, the rotor system of the motor includes radial air flotation bearings 111. When the motor shaft rotates, the radial air flotation bearings draw in gas, forming an air film that supports the high-speed rotation of the rotor. Simultaneously, the thrust bearing (if present) also forms an air film, resulting in no contact between the thrust shaft and the bearings, minimal bearing wear, and significant reduction or even elimination of mechanical losses and noise. As shown, the impeller 200 is located at the end of the rotor 101 and is used to compress low-temperature, low-pressure refrigerant gas from the evaporator to form high-temperature, high-pressure refrigerant gas that is discharged into the condenser. Here, the terms "radial" and "axial" refer to the radial and axial directions of the rotor or its rotation axis. In embodiments of the present invention, the rotor system 101 includes two radial bearings with a certain spacing between them, and they can be symmetrically distributed on the rotor. In one embodiment of the present invention, the radial bearings are foil-type dynamic pressure air flotation bearings. When gas is introduced into the bearing location, an air film can be formed, thereby achieving the air flotation effect.

[0047] To withstand the axial thrust generated during compressor operation, in one embodiment of the present invention, the rotor system further includes a thrust disk 112 and a thrust bearing 113. The thrust disk 112 and thrust bearing 113 are optional. The thrust disk 112 can be located at either end of the rotor, or one thrust disk 112 can be located at each end of the rotor. When only one thrust disk is provided, a thrust bearing 113 can be located on each side of the thrust disk 112, with the working surfaces of both thrust bearings 113 facing the thrust disk 112. Therefore, they can withstand axial thrust in different directions; specifically, the two thrust bearings 113 can withstand axial thrust in opposite directions. When two thrust disks are provided, a thrust bearing 113 can be respectively provided on opposite sides or on opposite sides of the two thrust disks 112. The working surfaces of the two thrust bearings 113 face the thrust disks 112, so they can withstand axial thrust in different directions. Specifically, the axial thrust directions that the two thrust bearings 113 can withstand are opposite. In one embodiment of the present invention, the thrust bearing is a foil-type hydrodynamic air bearing. When gas is introduced into the bearing position, an air film can be formed, thereby achieving an air flotation effect.

[0048] Furthermore, in different embodiments of the present invention, single-stage, double-stage, or multi-stage impellers can be provided according to actual needs. Specifically, when only a single-stage impeller is provided, the impeller 200 can be located at any end of the rotor, and the side with the impeller can be designated as the high-pressure side, while the side without the impeller is designated as the low-pressure side. When two-stage impellers are provided, the two impellers can be located at both ends of the rotor, or both can be located at any end of the rotor. When they are located at both ends of the rotor, the side with the preceding impeller can be designated as the low-pressure side, while the side with the following impeller can be designated as the high-pressure side. When both are located at one end of the rotor, the side with the impeller can be designated as the high-pressure side, while the side without the impeller is designated as the low-pressure side. Similarly, when multiple impellers are provided, the multiple impellers can be equally or unequally distributed at both ends of the rotor, or all can be distributed at any one end of the rotor. When they are distributed at both ends of the rotor, the side with the preceding impeller can be designated as the low-pressure side, and the side with the following impeller as the high-pressure side. When all impellers are distributed at one end of the rotor, the side with the impellers can be designated as the high-pressure side, and the side without impellers as the low-pressure side. Based on this, as shown in the figure, when the rotor rotates, a portion of the high-pressure gas compressed by the impellers in the main air path will enter the radial bearing on the high-pressure side under pressure, then pass through the air gap between the motor stator and rotor into the radial bearing on the low-pressure side, and return to the main air path. When a thrust disc and thrust bearing are provided, the high-pressure gas will also form a gas film through the thrust bearing, bearing axial thrust. To effectively reduce the axial thrust on the thrust bearing, in one embodiment of the present invention, the impeller on the low-pressure side and the impeller on the high-pressure side are arranged back-to-back, thereby causing the axial thrust directions of the impellers on the high-pressure side and the low-pressure side to be opposite and thus cancel each other out. In one embodiment of the present invention, the impeller is a closed impeller. In one embodiment of the present invention, the impeller is fixed to the rotor by a locking nut.

[0049] The housing has a first chamber and a second chamber at its two ends, with the impeller disposed within the first chamber and / or the second chamber. The inlet of the first chamber is connected to the inlet of the compressor; that is, the inlet is the inlet of the first chamber. A connecting pipe connects the first and second chambers. Gas flows out of the outlet of the first chamber, enters the connecting pipe, and then enters the second chamber through the inlet. The outlet of the second chamber is connected to the exhaust port of the compressor; that is, the exhaust port is the outlet of the second chamber. In an embodiment of the invention, a first end cover and a second end cover are respectively provided at the outlets of the first and second chambers. Gaps exist between the first and second end covers and the rotor and impeller, allowing gas to pass through these gaps from the main air path into the air bearing or from the air bearing back into the main air path. Furthermore, pressure shells are respectively provided on the outer sides of both ends of the motor, and a sealing ring is provided between the pressure shell and the impeller. The sealing ring can significantly reduce the backflow effect from the impeller outlet to the inlet, which can further improve the compressor efficiency. In order to reduce the compression power consumption of the impeller, in one embodiment of the present invention, an interstage air injection hole is also provided on the connecting pipe to connect the exhaust gas from the economizer and cool the gas, thereby achieving the purpose of reducing the compression power consumption of the impeller and improving the efficiency of the system.

[0050] like Figure 1 As shown, the refrigeration module 001 further includes a condenser 012 and a throttling device 013. The inlet of the condenser 012 is connected to the exhaust port of the air-float centrifugal compressor 011, used to cool the refrigerant in the first state to obtain a refrigerant in the second state. The temperature of the refrigerant in the second state is lower than that of the refrigerant in the first state, but the pressure remains essentially unchanged. In one embodiment of the invention, to improve refrigeration efficiency, a fan 014 is also provided at the fins of the condenser 012. The fan 014 introduces ambient temperature air into the fins of the condenser 012, allowing the heat of the high-temperature refrigerant inside the condenser 012 to exchange with the air, thereby achieving condensation. The throttling device 013 is connected to the outlet of the condenser 012 to throttle the refrigerant in the second state. The throttled refrigerant rapidly expands to form a third state. The pressure of the refrigerant in the third state is lower than that of the refrigerant in the second state, but the temperature remains essentially unchanged. The refrigerant in the third state enters an intermediate heat exchanger to exchange heat with the coolant. In embodiments of the present invention, the throttling device refers to a device or component used to reduce gas pressure to achieve evaporation, such as an expansion valve, capillary tube, or throttling tube.

[0051] In order to calculate the system's cooling demand and thus control the operating status of various devices or modules, as well as to protect the system operation, in one embodiment of the present invention, a temperature sensor T and a pressure sensor P are also provided in the cooling module 001. As shown in the figure, the temperature sensor T and the pressure sensor P may be located, for example, at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air-float centrifugal compressor.

[0052] The intermediate heat exchanger includes two inlets and two outlets, thus forming refrigerant pipelines and coolant pipelines. The inlet and outlet of the refrigerant pipeline are designated as the first inlet and first outlet, respectively. The first inlet is connected to the throttling device 013, and the first outlet is connected to the air inlet of the air-float centrifugal compressor 011. The inlet and outlet of the coolant pipeline are designated as the second inlet and second outlet, respectively connected to the inlet and outlet of the pipeline in the cooling module. The coolant pipeline is arranged around the refrigerant pipeline to allow heat exchange between the coolant and refrigerant. In one embodiment of the invention, a plate heat exchanger is used as the intermediate heat exchanger.

[0053] As shown in the figure, in one embodiment of the present invention, the core component of the cooling module 003 is a water pump 031, which provides power for the circulation of coolant. The water pump 031 is connected to the second inlet of the intermediate heat exchanger via a water pipe, delivering coolant into the intermediate heat exchanger. After transferring heat to the refrigerant, the coolant travels through a pipeline to an energy storage device. The heat generated by the energy storage device, such as the cell of an energy storage battery, is transferred to the coolant, and the heated coolant returns to the water pump, thus circulating. In one embodiment of the present invention, to improve heat exchange efficiency, the coolant flow direction and the refrigerant flow direction are exactly opposite in the intermediate heat exchanger. For example, the first inlet and second outlet of the intermediate heat exchanger can be located on the first side of the intermediate heat exchanger, and the second inlet and first outlet can be located on the second side of the intermediate heat exchanger opposite to the first side. In one embodiment of the present invention, the cooling module also includes a degassing and replenishment module, which includes an expansion tank, a gas storage pipe, and a water replenishment pipe. The gas storage pipe is connected to the second inlet of the intermediate heat exchanger via a tee, and the water supply pipe is connected to the inlet of the water pump via a tee. The expansion tank includes a tank body and a lid, and a pressure relief valve is provided on the lid. When the pressure reaches the set value, the pressure valve opens and the system releases pressure.

[0054] In the aforementioned energy storage thermal management system, the refrigerant circulation includes: the refrigerant is compressed centrifugally by the air-float centrifugal compressor; the compressed high-temperature refrigerant then travels through pipelines to the condenser; a fan draws ambient-temperature air into the condenser fins; the condenser exchanges heat between the high-temperature refrigerant and the air; the condensed refrigerant travels through pipelines to the throttling device, which throttles the refrigerant; the throttled refrigerant rapidly expands and enters the intermediate heat exchanger; in the intermediate heat exchanger, the throttled refrigerant absorbs heat from the coolant, thus lowering the coolant to the desired temperature; the evaporated refrigerant continues through pipelines to the filter element, which filters out system impurities; the filtered refrigerant then returns to the compressor. The coolant circulation includes: the coolant is pumped into the intermediate heat exchanger by the water pump, transferring heat to the refrigerant; then, it travels through pipelines to the energy storage device; in the energy storage device, the generated heat is transferred back to the coolant; and the coolant returns to the water pump. This completes the thermal management of the energy storage system.

[0055] Although various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. An energy storage thermal management system based on an air-float centrifugal compressor, characterized in that, include: A refrigeration module, configured to provide a refrigerant cycle, includes: An air-float centrifugal compressor configured to compress a refrigerant to form a refrigerant in a first state includes a motor, an impeller, an inlet, an outlet, and a connecting pipe. The motor includes a housing and a rotor. A first chamber and a second chamber are respectively located at both ends of the housing. An air-float radial bearing is provided on the rotor. A thrust disk is provided at the end of the rotor. Air-float thrust bearings are provided on one or both sides of the thrust disk. The impeller is arranged at the end of the rotor and located within the first chamber and / or the second chamber. The inlet communicates with the inlet of the first chamber, and the outlet communicates with the outlet of the second chamber. Both ends of the connecting pipe are respectively connected to the outlet of the first chamber and the inlet of the second chamber. A condenser, its inlet connected to the exhaust port of the air-float centrifugal compressor, is configured to cool the refrigerant in the first state to form a refrigerant in a second state, the second state having a lower temperature than the first state and both having the same pressure; and A throttling device, connected to the outlet of the condenser, throttles the refrigerant in the second state, causing it to expand to the third state, where the pressure in the third state is lower than that in the second state and the two states are at the same temperature. Intermediate heat exchanger, including: A refrigerant pipeline, including a first inlet and a first outlet, wherein the first inlet is connected to the outlet of the throttling device, and the first outlet is connected to the inlet of the air-float centrifugal compressor; and A coolant piping system, arranged to allow heat exchange between the coolant and refrigerant within the coolant piping system, the coolant piping system being connected to the piping of a cooling module, including a second inlet and a second outlet; and A cooling module configured to provide coolant circulation for cooling the energy storage device, the cooling module including a water pump configured to power the coolant circulation.

2. The energy storage thermal management system as described in claim 1, characterized in that, It also includes at least one temperature sensor and at least one pressure sensor.

3. The energy storage thermal management system as described in claim 2, characterized in that, The temperature sensor is located at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air flotation centrifugal compressor.

4. The energy storage thermal management system as described in claim 2, characterized in that, The pressure sensor is located at the first outlet of the intermediate heat exchanger and / or the exhaust port of the air flotation centrifugal compressor.

5. The energy storage thermal management system as described in claim 1, characterized in that, It also includes a fan located at the condenser and configured to introduce ambient air into the condenser for heat exchange.

6. The energy storage thermal management system as described in claim 1, characterized in that, The air flotation centrifugal compressor also includes an interstage air supply port, which is located on the connecting pipe.

7. The energy storage thermal management system as described in claim 1, characterized in that, The intermediate heat exchanger includes a plate heat exchanger.

8. The energy storage thermal management system as described in claim 1, characterized in that, The first inlet and the second outlet are located on the first side of the intermediate heat exchanger, and the second inlet and the first outlet are located on the second side of the intermediate heat exchanger opposite to the first side.

9. The energy storage thermal management system as described in claim 1, characterized in that, It also includes a degassing and liquid replenishment module, which comprises: An expansion pot with a pressure relief valve on its lid; The gas storage pipe is connected to the second inlet of the intermediate heat exchanger via a tee; and The water supply pipe is connected to the inlet of the water pump via a tee.

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