A refrigeration system and method for liquid flow battery system

Abstract

A refrigeration system and method for a liquid flow battery system, wherein a temperature sensor for detecting the temperature of the electrolyte is provided on the electrolyte storage tank of the liquid flow battery system, and the refrigeration system comprises: a controller, a cooling device, and an electric pump; the controller is electrically connected to the temperature sensor, the cooling device, and the electric pump respectively, and the liquid flow battery system, the cooling device, and the electric pump are connected in sequence through pipelines, and the pipelines are filled with nitrogen; the controller continuously obtains the electrolyte temperature detected by the temperature sensor, and when it is higher than a preset temperature threshold, sends a start instruction to the cooling device and the electric pump; after starting, the cooling device cools the nitrogen output from the liquid flow battery system to obtain liquid nitrogen; after starting, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification. The embodiment of the present application can cool the electrolyte in the electrolyte storage tank, thereby improving the energy supply efficiency of the liquid flow battery system.

Description

Technical Field

[0001] The present invention relates to liquid flow battery technology, and more particularly to a refrigeration system and method for liquid flow battery system. Background Art

[0002] Liquid flow battery systems have the functions of electrical energy storage and efficient conversion, long service life, environmental protection, and safety. They are easy to match with solar and wind power generation, greatly reducing equipment costs and providing technical guarantees for the use of renewable energy.

[0003] However, the flow battery system generates a large amount of heat during operation, which affects the energy supply efficiency of the flow battery system. Summary of the invention

[0004] The present application provides a refrigeration system and method applied to a liquid flow battery system, which can cool the electrolyte, thereby improving the energy supply efficiency of the liquid flow battery system.

[0005] On the one hand, the present application provides a refrigeration system applied to a liquid flow battery system, comprising: a temperature sensor for detecting the temperature of the electrolyte is provided on the electrolyte storage tank of the liquid flow battery system, and the refrigeration system comprises: a controller, a cooling device, and an electric pump;

[0006] The controller is electrically connected to the temperature sensor, the cooling device, and the electric pump, respectively; the flow battery system and the cooling device, the cooling device and the electric pump, and the electric pump and the flow battery system are all connected via pipelines, and the pipelines are filled with nitrogen;

[0007] The controller is used to continuously obtain the electrolyte temperature detected by the temperature sensor, and send a start instruction to the cooling device and the electric pump when the electrolyte temperature is higher than a preset temperature threshold;

[0008] The cooling device is used to cool the nitrogen output from the liquid flow battery system to obtain liquid nitrogen after startup;

[0009] The electric pump is used to extract liquid nitrogen from the cooling device and output it to the electrolyte storage tank of the liquid flow battery system after startup, so that the liquid nitrogen can cool the electrolyte in the electrolyte storage tank by gasification.

[0010] On the other hand, the present application provides a refrigeration method, applied to the refrigeration system as described above, comprising:

[0011] The controller continuously obtains the electrolyte temperature detected by the temperature sensor, and sends a start instruction to the cooling device and the electric pump when the electrolyte temperature is higher than a preset temperature threshold;

[0012] The cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen after startup;

[0013] After being started, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification.

[0014] Compared with the related art, the embodiment of the present application continuously obtains the electrolyte temperature detected by the temperature sensor, and when the electrolyte temperature is higher than the preset temperature threshold, sends a start instruction to the cooling device and the electric variable flow pump, the cooling device cools the nitrogen output from the flow battery system to obtain liquid nitrogen, and the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification. The embodiment of the present application can cool the electrolyte in the electrolyte storage tank, thereby improving the energy supply efficiency of the flow battery system.

[0015] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings.

[0016] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0018] Figure 1 This is a schematic diagram of the structure of a refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0019] Figure 2 This is a schematic diagram of the structure of another refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0020] Figure 3 This is a structural schematic diagram of another refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0021] Figure 4 This is a structural schematic diagram of another refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0022] Figure 5 This is a structural schematic diagram of another refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0023] Figure 6 This is a structural schematic diagram of another refrigeration system applied to a liquid flow battery system according to an embodiment of the present application;

[0024] Figure 7 This is a schematic diagram of the structure of an electrolyte storage tank in a flow battery system that cooperates with a refrigeration system in an embodiment of the present application;

[0025] Figure 8 This is a schematic diagram of the structure of an electrolyte storage tank in another liquid flow battery system that cooperates with a refrigeration system in an embodiment of the present application;

[0026] Fig. 9 This is a schematic diagram of the structure of an electrolyte storage tank in a flow battery system in cooperation with a refrigeration system in another embodiment of the present application;

[0027] Fig.10 This is a schematic diagram of the structure of an electrolyte storage tank in a flow battery system in cooperation with a refrigeration system in another embodiment of the present application;

[0028] Fig.11 This is a schematic diagram of the structure of an electrolyte storage tank in a flow battery system in cooperation with a refrigeration system in another embodiment of the present application;

[0029] Fig.12 A schematic flow chart of a refrigeration method corresponding to a refrigeration system applied to a liquid flow battery system according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0031] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0032] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0033] In recent years, the social economy has developed rapidly, and the power system has been constantly updated and improved. With the discovery and utilization of many new energy sources, how to store energy more efficiently has become a hot topic of concern in the power industry, which directly affects the development of the power system. Liquid flow batteries are widely used in the energy storage industry due to their good stability and safety, and have become the mainstream technical solution in the field of energy storage. Liquid flow batteries are based on the redox reaction generated by the flow of electrolyte, which enables vanadium ions to continuously convert their valence states, thereby achieving the purpose of charging and discharging. Since the flow of electrolyte is the core concept of the operation of liquid flow batteries, the design of the pipelines on which the electrolyte flow relies is crucial.

[0034] At present, liquid flow batteries generate a large amount of heat during operation. If the heat cannot be discharged from the system in time, the charging and discharging efficiency of the system will be reduced, the electrolyte will crystallize, and the liquid flow battery system will be damaged. Most of the cooling methods currently used are based on pure water and ethylene glycol solutions to discharge the heat from the liquid flow battery system. However, since the solution of the liquid flow battery is corrosive to a certain extent, it will cause certain corrosion to the heat exchanger to a large extent, causing leakage, thereby contaminating the electrolyte, resulting in reduced battery efficiency or even failure to work normally.

[0035] To this end, the present application embodiment provides a refrigeration system applied to a liquid flow battery system, such as Figure 1 As shown, a temperature sensor (not shown) for detecting the temperature of the electrolyte is provided on the electrolyte storage tank of the flow battery system, and the refrigeration system includes: a controller 11, a cooling device 12, and an electric pump 13;

[0036] The controller 11 is electrically connected to the temperature sensor, the cooling device 12, and the electric pump 13 respectively; the flow battery system and the cooling device 12, the cooling device 12 and the electric pump 13, and the electric pump 13 and the flow battery system are all connected through pipelines, and the pipelines are filled with nitrogen;

[0037] The controller 11 is used to continuously obtain the electrolyte temperature detected by the temperature sensor, and send a start instruction to the cooling device 12 and the electric pump 13 when the electrolyte temperature is higher than a preset temperature threshold;

[0038] The cooling device 12 is used to cool the nitrogen output from the liquid flow battery system to obtain liquid nitrogen after startup;

[0039] The electric pump 13 is used to extract liquid nitrogen from the cooling device 12 after startup and output it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification.

[0040] When liquid nitrogen passes through the liquid flow battery system and is vaporized into nitrogen, it enters the cooling device 12. The cooling device 12 cools the nitrogen to obtain liquid nitrogen. The electric pump then extracts liquid nitrogen from the cooling device 12 and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank through vaporization. The above process is continuously repeated until the electrolyte temperature detected by the temperature sensor reaches a preset standard, and a stop command is sent to the cooling device 12 and the electric pump 13.

[0041] The electric pump may be an electrically controlled variable flow air pump. The preset temperature threshold may be 35°C.

[0042] The refrigeration system applied to the liquid flow battery system provided in the embodiment of the present application continuously obtains the electrolyte temperature detected by the temperature sensor, and when the electrolyte temperature is higher than the preset temperature threshold, sends a start instruction to the cooling device and the electrically controlled variable flow pump, the cooling device cools the nitrogen output from the liquid flow battery system to obtain liquid nitrogen, and the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification. The embodiment of the present application can cool the electrolyte in the electrolyte storage tank, thereby improving the energy supply efficiency of the liquid flow battery system.

[0043] In an exemplary embodiment, Figure 2 As shown, the cooling device 12 includes: a compressor 121, a radiator 122, an expansion valve 123, and a static pressure box 124;

[0044] The cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen after startup, comprising:

[0045] The compressor 121 is used to compress the nitrogen from the liquid flow battery system to obtain compressed nitrogen;

[0046] The radiator 122 is used to cool the nitrogen gas inputted into the radiator 122 to obtain liquid nitrogen;

[0047] The expansion valve 123 is used to decompress the liquid nitrogen input to the expansion valve 123, obtain the decompressed liquid nitrogen and output it to the static pressure tank 124;

[0048] After being started, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, comprising:

[0049] After being started, the electric pump 13 extracts liquid nitrogen from the static pressure tank 124 and outputs it to the electrolyte storage tank of the liquid flow battery system.

[0050] In an exemplary embodiment, Figure 3 As shown, the refrigeration system further includes: an oil-gas separator 14 and a filter 15;

[0051] The oil-gas separator 14 is used to perform oil-gas separation on the compressed nitrogen from the compressor, obtain the oil-gas separated nitrogen and output it to the radiator 122;

[0052] The filter 15 is used to remove moisture from the liquid nitrogen from the radiator 122 , obtain the liquid nitrogen after the moisture removal process, and output it to the expansion valve 123 .

[0053] The function of the oil-gas separator is to effectively separate the nitrogen used as the refrigerant and the oil in the compressor to prevent the oil in the refrigerant from contaminating the medium in the flow battery and causing a decrease in the charging and discharging efficiency.

[0054] The function of the filter is to remove moisture from the refrigerant to prevent moisture from entering and reducing refrigeration efficiency.

[0055] In an exemplary embodiment, Figure 4As shown, the refrigeration system further includes: a low-pressure switch 14 and a nitrogen storage tank 15; the low-pressure switch 14 is arranged on the pipeline from the expansion valve 123 to the compressor (the figure takes the low-pressure switch 14 as an example of being arranged on the pipeline between the expansion valve 123 and the static pressure tank 124); the nitrogen storage tank is connected to the pipeline between the flow battery system and the compressor 121 through a first valve, and the first valve is electrically connected to the controller (not shown in the figure);

[0056] The low-pressure switch 14 is used to generate an alarm when the pressure in the pipeline is lower than a first pressure threshold;

[0057] The controller 11 is further configured to send an opening instruction to the first valve when the low-pressure switch alarms, so that the nitrogen in the nitrogen storage tank is filled into the pipeline.

[0058] It should be noted that the pipeline from the expansion valve 123 to the compressor 121 is a pipeline formed according to the flow direction of liquid nitrogen or nitrogen gas.

[0059] In an exemplary embodiment, Figure 5 As shown, the refrigeration system further includes: a high-pressure switch 16, which is arranged on the pipeline from the compressor 121 to the expansion valve 123 (the figure takes the low-pressure switch 16 as an example of being arranged on the pipeline from the compressor 121 to the oil-gas separator 14);

[0060] The high pressure switch 16 is used to give an alarm when the pressure in the pipeline is greater than a second pressure threshold;

[0061] The controller 11 is further configured to send a closing instruction to the first valve when the high pressure switch alarms, so as to stop the nitrogen in the nitrogen storage tank from being charged into the pipeline.

[0062] It should be noted that the pipeline from the compressor 121 to the expansion valve 123 is a pipeline formed according to the flow direction of liquid nitrogen or nitrogen gas.

[0063] In an exemplary embodiment, Figure 6 As shown, the refrigeration system further includes: a heater 17, the heater 17 is arranged on the pipeline between the liquid flow system and the electric pump 13, and the heater 17 is electrically connected to the controller 11 (not shown in the figure);

[0064] Figure 7 It is a structural diagram of the electrolyte storage tank corresponding to the refrigeration system. Figure 7 The electrolyte storage tank in the embodiment is located in the liquid flow battery system in the above embodiment in actual application, such as Figure 7As shown, the pipeline between the flow battery system and the heater 17 includes: a first pipeline; a second valve is provided on the first pipeline, the second valve is electrically connected to the controller, and one end of the first pipeline connected to the battery system extends into the electrolyte storage tank;

[0065] After being started, the electric pump extracts liquid nitrogen from the static pressure tank of the cooling device and inputs it into the electrolyte storage tank of the liquid flow battery system, including:

[0066] After being started, the electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system through the pipeline between the electric pump and the heater and the first pipeline in sequence.

[0067] In practical applications, the end of the first pipeline connected to the battery system may extend below the electrolyte level of the electrolyte storage tank, or may not extend below the electrolyte level of the electrolyte storage tank ( Figure 7 An example is shown in which one end of the first pipeline connected to the battery system extends below the electrolyte level in the electrolyte storage tank).

[0068] In an exemplary embodiment, Figure 8 As shown, the electrolyte storage tank is provided with a hydrogen sensor for detecting the hydrogen concentration in the electrolyte, and the hydrogen sensor is electrically connected to the controller;

[0069] The pipeline between the flow battery system and the heater further includes: a second pipeline, on which a third valve is provided, the third valve is electrically connected to the controller, and one end of the second pipeline connected to the battery system extends into the electrolyte storage tank and is located below the liquid level of the electrolyte;

[0070] The controller 11 is further used to obtain the hydrogen concentration detected by the hydrogen sensor, and when the hydrogen concentration is greater than a preset concentration threshold, send a closing instruction to the second valve, send an opening instruction to the third valve, and send a start instruction to the heater 17;

[0071] The electric pump 13 is also used to extract liquid nitrogen from the static pressure tank in the cooling device and output it to the heater 17;

[0072] The heater 17 is used to heat the liquid nitrogen input to itself after startup to generate nitrogen gas and output it to the electrolyte in the electrolyte storage tank of the liquid flow battery system through the second pipeline to discharge the hydrogen in the electrolyte.

[0073] When nitrogen is filled into the electrolyte, it will displace the hydrogen in the electrolyte and thus precipitate the hydrogen from the electrolyte.

[0074] Hydrogen is adsorbed on the reaction interface, resulting in a decrease in the available reaction interface area, which leads to a decrease in the battery coulomb and energy efficiency. In addition, after the hydrogen circulates with the electrolyte and reaches the storage tank, part of the gas will be precipitated from the electrolysis. The refrigeration system for the liquid flow battery system provided in the embodiment of the present application fills the electrolyte in the electrode liquid storage tank with nitrogen through the second pipeline, so that the hydrogen in the electrolyte can be quickly precipitated.

[0075] In specific applications, Fig. 9 As shown, an exhaust pipeline is arranged above the electrolyte storage tank, and a breathing valve is arranged on the exhaust pipeline;

[0076] When the hydrogen gas gathered above the liquid surface of the electrolyte storage tank reaches a corresponding pressure to open the breathing valve, the hydrogen gas gathered above the liquid surface of the electrolyte storage tank is discharged.

[0077] In an exemplary embodiment, Fig.10 As shown, one end of the second pipeline connected to the battery system extends below the liquid level of the electrolyte in the electrolyte storage tank and is close to the bottom of the electrolyte storage tank, and the one end of the second pipeline connected to the battery system includes: an output portion arranged parallel to the bottom of the electrolyte storage tank and including multiple output branches.

[0078] When the end of the second pipeline connected to the battery system is arranged near the bottom of the electrolyte storage tank and is arranged as an output part including multiple output branches, nitrogen can be evenly mixed into the electrolyte, thereby better precipitating hydrogen from the electrolyte.

[0079] When nitrogen is charged into the electrolyte in the electrolyte storage tank through the second pipeline, the water pump of the flow battery system is in a stopped state.

[0080] According to Stokes' law, the rising velocity v of a bubble in a liquid can be expressed as:

[0081] v=(2 / 9)*(r^2)*g*(ρ2-ρ1) / η;

[0082] Among them, r represents the radius of the bubble, g represents the gravitational acceleration, ρ2 represents the density of the bubble, ρ1 represents the density of the liquid, and η represents the viscosity of the liquid.

[0083] When the height of the working liquid level is known to be H, the rising speed of the bubbles is v, t=H / v, and the time for nitrogen to be released in the electrolyte storage tank can be calculated. When the hydrogen sensor cannot sense the gas in the tank, the filling of nitrogen into the electrolyte storage tank can be stopped after time t1 (t1>t), and at this time all the hydrogen in the electrolyte is precipitated.

[0084] When nitrogen is filled into the electrolyte storage tank through the second pipeline, the nitrogen originally used to cool the electrolyte in the pipeline will be reduced, and the refrigeration efficiency will decrease. Therefore, the controller can send an opening command to the first valve, and the first valve opens to fill nitrogen into the pipeline. When the high-pressure switch alarms, the controller sends a closing command to the first valve, and the first valve closes to stop filling nitrogen into the pipeline.

[0085] In an exemplary embodiment, Fig.11 As shown, a hydrogen detector for detecting the content of hydrogen condensed above the electrolyte storage tank is provided on the top of the electrolyte storage tank, and the hydrogen detector is electrically connected to the controller 11;

[0086] The pipeline between the flow battery system and the heater 17 also includes: a third pipeline, on which a fourth valve is provided, the fourth valve is electrically connected to the controller, and one end of the third pipeline connected to the battery system extends into the electrolyte storage tank and is located on the liquid surface of the electrolyte;

[0087] The controller 11 is further used to obtain the hydrogen content detected by the hydrogen detector, and when the hydrogen content is greater than a preset content threshold, send a closing instruction to the second valve and the third valve, send an opening instruction to the fourth valve, and send a start instruction to the heater;

[0088] The heater 17 is also used to heat the liquid nitrogen input into itself after startup to generate nitrogen gas and output it to the top of the electrolyte storage tank of the liquid flow battery system through the third pipeline, so that the hydrogen gas above the electrolyte storage tank can be discharged.

[0089] The space above the electrolyte storage tank is fixed, and the density of hydrogen is lower than that of nitrogen. Therefore, as more and more nitrogen is input into the electrolyte storage tank, the hydrogen will be squeezed out and discharged from the exhaust pipe.

[0090] In practical applications, the first valve, the second valve, the third valve and the fourth valve may specifically be solenoid valves.

[0091] The refrigeration system applied to the liquid flow battery system provided in the embodiment of the present application fills nitrogen into the top of the electrode liquid storage tank through the third pipeline, so that the hydrogen accumulated above the electrolyte storage tank is quickly discharged from the electrolyte storage tank, and the hydrogen in the electrolyte can be quickly precipitated, thereby avoiding the problem of safety accidents easily caused by the hydrogen concentration reaching a near value.

[0092] When the hydrogen detector detects that the hydrogen content in the tank reaches the preset threshold, purging is required. At this time, the controller sends a start command to the electric pump, an open command to the fourth valve, and a close command to the second valve and the third valve to purge the hydrogen accumulated above the electrolyte storage tank. When the hydrogen detector does not alarm, after purging for another 5 minutes, the controller sends a stop command to the electric pump.

[0093] When the electrolyte temperature detected by the temperature sensor is higher than the preset temperature threshold again, the controller sends a closing command to the fourth valve and an opening command to the second valve. At this time, since nitrogen was previously input into the electrolyte storage tank for hydrogen precipitation and the precipitated hydrogen was quickly discharged from the electrolyte storage tank, nitrogen will be more or less discharged from the electrolyte storage tank, so the nitrogen content in the pipeline is reduced, thereby reducing the cooling efficiency of the electrolyte. Therefore, the controller sends an opening command to the first valve to fill the nitrogen storage tank with nitrogen into the pipeline.

[0094] The present application embodiment provides a refrigeration method, which is applied to the refrigeration system described in any of the above embodiments. Fig.12 As shown, the method includes:

[0095] Step 201, the controller continuously obtains the electrolyte temperature detected by the temperature sensor, and sends a start instruction to the cooling device and the electric pump when the electrolyte temperature is higher than a preset temperature threshold;

[0096] Step 202: After being started, the cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen;

[0097] Step 203: After being started, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification.

[0098] In an exemplary embodiment, the cooling device includes: a compressor, a radiator, an expansion valve, and a static pressure tank.

[0099] In an exemplary embodiment, the cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen after startup, comprising:

[0100] First, the compressor compresses the nitrogen from the liquid flow battery system to obtain compressed nitrogen;

[0101] Secondly, the radiator cools down the nitrogen gas input into itself to obtain liquid nitrogen;

[0102] Finally, the expansion valve decompresses the liquid nitrogen input into the expansion valve, obtains the decompressed liquid nitrogen and outputs it to the static pressure tank.

[0103] In an exemplary embodiment, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system after being started, including:

[0104] After being started, the electric pump extracts liquid nitrogen from the static pressure tank and outputs it to the electrolyte storage tank of the liquid flow battery system.

[0105] In an exemplary embodiment, the refrigeration system further includes: an oil-gas separator and a filter.

[0106] In an exemplary embodiment, the method further comprises:

[0107] First, the oil-gas separator performs oil-gas separation on the compressed nitrogen from the compressor to obtain the oil-gas separated nitrogen and output it to the radiator;

[0108] Secondly, the filter performs a moisture removal process on the liquid nitrogen from the radiator to obtain the moisture-removed liquid nitrogen and output it to the expansion valve.

[0109] In an exemplary embodiment, the refrigeration system as shown in the figure also includes: a low-pressure switch and a nitrogen storage tank; the low-pressure switch is arranged on the pipeline between the expansion valve and the compressor; the nitrogen storage tank is connected to the pipeline between the liquid flow battery system and the compressor through a first valve, and the first valve is electrically connected to the controller.

[0110] In an exemplary embodiment, the method further comprises:

[0111] First, the low-pressure switch generates an alarm when the pressure in the pipeline is lower than a first pressure threshold;

[0112] Secondly, the controller is also used to send an opening instruction to the first valve when the low-pressure switch alarms, so that the nitrogen in the nitrogen storage tank is filled into the pipeline.

[0113] In an exemplary embodiment, the refrigeration system further includes: a high-pressure switch, wherein the high-pressure switch is disposed on a pipeline from the compressor to the expansion valve.

[0114] In an exemplary embodiment, the method further comprises:

[0115] First, the high-pressure switch alarms when the pressure in the pipeline is greater than a second pressure threshold;

[0116] Secondly, when the high-pressure switch alarms, the controller sends a closing instruction to the first valve to stop the nitrogen in the nitrogen storage tank from being charged into the pipeline.

[0117] In an exemplary embodiment, the refrigeration system further includes: a heater, which is disposed on a pipeline between the liquid flow system and the electric pump, and the heater is electrically connected to the controller.

[0118] In an exemplary embodiment, the pipeline between the liquid flow battery system and the heater includes: a first pipeline; a second valve is provided on the first pipeline, the second valve is electrically connected to the controller, and one end of the first pipeline connected to the battery system extends into the electrolyte storage tank.

[0119] In an exemplary embodiment, after the electric pump is started, liquid nitrogen is extracted from the static pressure tank of the cooling device and input into the electrolyte storage tank of the liquid flow battery system, including:

[0120] After being started, the electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system through the pipeline between the electric pump and the heater and the first pipeline in sequence.

[0121] In an exemplary embodiment, a hydrogen sensor for detecting the hydrogen concentration in the electrolyte is disposed on the electrolyte storage tank, and the hydrogen sensor is electrically connected to the controller.

[0122] In an exemplary embodiment, the pipeline between the liquid flow battery system and the heater also includes: a second pipeline, on which a third valve is provided, the third valve is electrically connected to the controller, and one end of the second pipeline connected to the battery system extends into the electrolyte storage tank and is located below the liquid level of the electrolyte.

[0123] In an exemplary embodiment, the method further comprises:

[0124] First, the controller obtains the hydrogen concentration detected by the hydrogen sensor, and when the hydrogen concentration is greater than a preset concentration threshold, sends a closing instruction to the second valve, sends an opening instruction to the third valve, and sends a starting instruction to the heater;

[0125] Secondly, the electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs it to the heater;

[0126] Finally, the heater is used to heat the liquid nitrogen input into itself after startup to generate nitrogen gas and output it to the electrolyte in the electrolyte storage tank of the liquid flow battery system through the second pipeline to discharge the hydrogen in the electrolyte.

[0127] In an exemplary embodiment, an exhaust pipeline is provided above the electrolyte storage tank, and a breathing valve is provided on the exhaust pipeline.

[0128] In an exemplary embodiment, the method further comprises:

[0129] The exhaust pipeline discharges the hydrogen accumulated above the liquid surface of the electrolyte storage tank after the hydrogen accumulated above the liquid surface of the electrolyte storage tank reaches a corresponding pressure to open the breathing valve.

[0130] In an exemplary embodiment, one end of the second pipeline connected to the battery system extends below the liquid level of the electrolyte in the electrolyte storage tank and is close to the bottom of the electrolyte storage tank, and the end of the second pipeline connected to the battery system includes: an output portion arranged parallel to the bottom of the electrolyte storage tank and including multiple output branches.

[0131] In an exemplary embodiment, a hydrogen detector for detecting the content of hydrogen condensed above the electrolyte storage tank is disposed on the top of the electrolyte storage tank, and the hydrogen detector is electrically connected to the controller.

[0132] In an exemplary embodiment, the pipeline between the liquid flow battery system and the heater also includes: a third pipeline, on which a fourth valve is provided, the fourth valve is electrically connected to the controller, and one end of the third pipeline connected to the battery system extends into the electrolyte storage tank and is located on the liquid surface of the electrolyte.

[0133] In an exemplary embodiment, the method further comprises:

[0134] First, the controller obtains the hydrogen content detected by the hydrogen detector, and when the hydrogen content is greater than a preset content threshold, sends a closing instruction to the second valve and the third valve, sends an opening instruction to the fourth valve, and sends a start instruction to the heater;

[0135] Secondly, after being started, the heater heats the liquid nitrogen input into itself to generate nitrogen gas and outputs it to the top of the electrolyte storage tank of the liquid flow battery system through the third pipeline, so that the hydrogen gas above the electrolyte storage tank is discharged.

[0136] The refrigeration method provided in the embodiment of the present application continuously obtains the electrolyte temperature detected by the temperature sensor, and when the electrolyte temperature is higher than the preset temperature threshold, sends a start instruction to the cooling device and the electrically controlled variable flow pump, the cooling device cools the nitrogen output from the flow battery system to obtain liquid nitrogen, and the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification. The embodiment of the present application can cool the electrolyte in the electrolyte storage tank, thereby improving the energy supply efficiency of the flow battery system.

[0137] An embodiment of the present application further provides a storage medium, on which computer executable commands are stored, and the computer executable commands are used to execute the refrigeration method described in any one of the above embodiments.

[0138] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A refrigeration system for a liquid flow battery system, characterized in that: The electrolyte storage tank of the flow battery system is provided with a temperature sensor for detecting the electrolyte temperature, and the refrigeration system comprises: a controller, a cooling device, and an electric pump; The controller is electrically connected to the temperature sensor, the cooling device, and the electric pump, respectively; the flow battery system and the cooling device, the cooling device and the electric pump, and the electric pump and the flow battery system are all connected via pipelines, and the pipelines are filled with nitrogen; The controller is used to continuously obtain the electrolyte temperature detected by the temperature sensor, and send a start instruction to the cooling device and the electric pump when the electrolyte temperature is higher than a preset temperature threshold; The cooling device is used to cool the nitrogen output from the liquid flow battery system to obtain liquid nitrogen after startup; The electric pump is used to extract liquid nitrogen from the cooling device and output it to the electrolyte storage tank of the liquid flow battery system after startup, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification; The refrigeration system further comprises: a heater, the heater being arranged on a pipeline between the liquid flow system and the electric pump, the heater being electrically connected to the controller; The pipeline between the flow battery system and the heater includes: a first pipeline; a second valve is arranged on the first pipeline, the second valve is electrically connected to the controller, and one end of the first pipeline connected to the battery system extends into the electrolyte storage tank; After being started, the electric pump extracts liquid nitrogen from the static pressure tank of the cooling device and inputs it into the electrolyte storage tank of the liquid flow battery system, including: After being started, the electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs the liquid nitrogen to the electrolyte storage tank of the liquid flow battery system through the pipeline between the electric pump and the heater and the first pipeline in sequence; The electrolyte storage tank is provided with a hydrogen sensor for detecting the hydrogen concentration in the electrolyte, and the hydrogen sensor is electrically connected to the controller; The pipeline between the flow battery system and the heater further includes: a second pipeline, on which a third valve is provided, the third valve is electrically connected to the controller, and one end of the second pipeline connected to the battery system extends into the electrolyte storage tank and is located below the liquid level of the electrolyte; The controller is further used to obtain the hydrogen concentration detected by the hydrogen sensor, and when the hydrogen concentration is greater than a preset concentration threshold, send a closing instruction to the second valve, send an opening instruction to the third valve, and send a starting instruction to the heater; The electric pump is also used to extract liquid nitrogen from the static pressure tank in the cooling device and output it to the heater; The heater is used to heat the liquid nitrogen input into itself after startup to generate nitrogen gas and output it to the electrolyte in the electrolyte storage tank of the liquid flow battery system through the second pipeline to discharge the hydrogen in the electrolyte.

2. The refrigeration system according to claim 1, characterized in that: The cooling device includes: a compressor, a radiator, an expansion valve, and a static pressure box; The cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen after startup, comprising: The compressor is used to compress the nitrogen from the liquid flow battery system to obtain compressed nitrogen; The radiator is used to cool the nitrogen gas inputted into the radiator to obtain liquid nitrogen; The expansion valve is used to decompress the liquid nitrogen input into the expansion valve, obtain the decompressed liquid nitrogen and output it to the static pressure tank; After being started, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, comprising: After being started, the electric pump extracts liquid nitrogen from the static pressure tank and outputs it to the electrolyte storage tank of the liquid flow battery system.

3. The refrigeration system according to claim 2, characterized in that: The refrigeration system further comprises: an oil-gas separator and a filter; The oil-gas separator is used to perform oil-gas separation on the compressed nitrogen from the compressor, obtain the oil-gas separated nitrogen and output it to the radiator; The filter is used to remove moisture from the liquid nitrogen from the radiator, obtain the liquid nitrogen after the moisture removal process and output it to the expansion valve.

4. The refrigeration system according to claim 3, characterized in that: The refrigeration system further includes: a low-pressure switch and a nitrogen storage tank; the low-pressure switch is arranged on the pipeline between the expansion valve and the compressor; the nitrogen storage tank is connected to the pipeline between the flow battery system and the compressor through a first valve, and the first valve is electrically connected to the controller; The low-pressure switch is used to give an alarm when the pressure in the pipeline is lower than a first pressure threshold; The controller is also used to send an opening instruction to the first valve when the low-pressure switch alarms, so that the nitrogen in the nitrogen storage tank is filled into the pipeline.

5. The refrigeration system according to claim 4, characterized in that: The refrigeration system further comprises: a high-pressure switch, which is arranged on a pipeline from the compressor to the expansion valve; The high-pressure switch is used to give an alarm when the pressure in the pipeline is greater than a second pressure threshold; The controller is also used to send a closing instruction to the first valve when the high-pressure switch alarms, so as to stop the nitrogen in the nitrogen storage tank from being charged into the pipeline.

6. The refrigeration system according to claim 1, characterized in that: One end of the second pipeline connected to the battery system extends below the liquid level of the electrolyte in the electrolyte storage tank and is close to the bottom of the electrolyte storage tank. The end of the second pipeline connected to the battery system includes: an output portion that is arranged parallel to the bottom of the electrolyte storage tank and includes multiple output branches.

7. The refrigeration system according to claim 6, characterized in that: A hydrogen detector for detecting the content of hydrogen condensed above the electrolyte storage tank is disposed on the top of the electrolyte storage tank, and the hydrogen detector is electrically connected to the controller; The pipeline between the flow battery system and the heater further includes: a third pipeline, on which a fourth valve is provided, the fourth valve is electrically connected to the controller, and one end of the third pipeline connected to the battery system extends into the electrolyte storage tank and is located on the liquid surface of the electrolyte; The controller is further used to obtain the hydrogen content detected by the hydrogen detector, and when the hydrogen content is greater than a preset content threshold, send a closing instruction to the second valve and the third valve, send an opening instruction to the fourth valve, and send a start instruction to the heater; The heater is also used to heat the liquid nitrogen input into itself after startup to generate nitrogen gas and output it to the top of the electrolyte storage tank of the liquid flow battery system through the third pipeline, so that the hydrogen gas above the electrolyte storage tank can be discharged.

8. A refrigeration method, characterized in that: Applied to the refrigeration system according to any one of claims 1 to 7, the method comprises: The controller continuously obtains the electrolyte temperature detected by the temperature sensor, and sends a start instruction to the cooling device and the electric pump when the electrolyte temperature is higher than a preset temperature threshold; After being started, the cooling device cools the nitrogen gas output from the liquid flow battery system to obtain liquid nitrogen; After being started, the electric pump extracts liquid nitrogen from the cooling device and outputs it to the electrolyte storage tank of the liquid flow battery system, so that the liquid nitrogen cools the electrolyte in the electrolyte storage tank by gasification; After being started, the electric pump extracts liquid nitrogen from the static pressure tank of the cooling device and inputs it into the electrolyte storage tank of the liquid flow battery system, including: After being started, the electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs the liquid nitrogen to the electrolyte storage tank of the liquid flow battery system through the pipeline between the electric pump and the heater and the first pipeline in sequence; The method further comprises: The controller obtains the hydrogen concentration detected by the hydrogen sensor, and when the hydrogen concentration is greater than a preset concentration threshold, sends a closing instruction to the second valve, sends an opening instruction to the third valve, and sends a starting instruction to the heater; The electric pump extracts liquid nitrogen from the static pressure tank in the cooling device and outputs it to the heater; After being started, the heater heats the liquid nitrogen input into itself to generate nitrogen gas, and outputs the nitrogen gas to the electrolyte in the electrolyte storage tank of the liquid flow battery system through the second pipeline, so as to discharge the hydrogen gas in the electrolyte.

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