A heat dissipation system applied to underwater energy storage, an underwater energy storage device and a heat dissipation method

Abstract

The application relates to a heat dissipation technology field of an underwater energy storage system, in particular to a heat dissipation system applied to underwater energy storage, an underwater energy storage device and a heat dissipation method, which comprise a heat exchanger and a circulating pipeline adapted to an underwater environment. The heat exchanger comprises a coil pipe capable of exchanging heat with an external water body; the circulating pipeline comprises three independent and cooperative pipelines: in the battery liquid cooling circulating pipeline, PACK liquid cooling plate cooling liquid absorbs battery heat, is cooled by a liquid evaporation heat exchange unit and returns; in the refrigerant circulating pipeline, low-pressure gaseous refrigerant is compressed into high-pressure gaseous refrigerant, is liquefied by a liquid condensation heat exchange unit, is depressurized, low-pressure liquid is heated and gasified by the liquid evaporation heat exchange unit and returns; in the external water body heat exchange circulating pipeline, fluid absorbs heat from the liquid condensation heat exchange unit, flows to the coil pipe, releases heat to the external water body and returns. The application realizes heat transfer of low-temperature battery cooling liquid to high-temperature water body, breaks through the season and water depth limitation and guarantees all-weather operation of the system.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation technology for underwater energy storage systems, and in particular to a heat dissipation system, underwater energy storage device, and heat dissipation method for underwater energy storage. Background Technology

[0002] As a key technology supporting the development of marine energy such as offshore wind power storage, underwater energy storage has lagged behind in development due to the high pressure of the underwater environment, the complexity of the water body, and the special heat dissipation requirements. The core bottleneck is that existing heat dissipation technologies are difficult to adapt to underwater working conditions.

[0003] The open-loop freshwater cooling and fan-based air conditioning solutions commonly used in onshore energy storage are completely unsuitable for underwater energy storage devices due to the lack of air convection in the underwater environment, the need to withstand the high pressure of the deep sea, and the inability to exchange air between the internal environment and the outside. For underwater scenarios, existing cooling technologies mainly fall into three typical categories, all of which have significant drawbacks:

[0004] Firstly, it adopts a circulation mode of "external wall radiator of energy storage chamber + single liquid cooling pipeline": such as Figure 1 As shown, the circulating pump 21 inside the protective casing 2 of the energy storage device drives the coolant to flow. First, the coolant flows through the PACK cold plate 22, absorbing heat generated by components such as the battery. Then, the coolant carrying heat enters the coil 11 of the heat exchanger 1, which is placed in a water environment, through the energy storage outlet 23. The coil 11 exchanges heat with the external water body (such as seawater or river water), dissipating heat into the water to achieve cooling. The cooled coolant then flows back to the PACK cold plate 22 through the energy storage inlet 24, thus completing the heat dissipation cycle. Simultaneously, the expansion tank 25 is used to balance the pipeline pressure, and the temperature sensor 26 and pressure sensor 27 monitor the temperature and pressure within the pipeline in real time, ensuring a stable and controllable circulating heat dissipation process. However, this solution is highly dependent on water temperature. Seawater / river water has significant temperature differences throughout the year, and surface water temperature often exceeds 30°C in summer. As the core of the energy storage system, the battery has stringent requirements for the temperature of the coolant flowing through the cold plate (usually needs to be maintained at 20~25°C). When the water temperature is higher than this threshold, the heat dissipation efficiency drops sharply or even fails, resulting in a shortened battery life and performance degradation due to heat accumulation, and extremely poor seasonal adaptability.

[0005] Secondly, an open-loop seawater cooling scheme is adopted, which directly uses seawater as a cooling medium to exchange heat with the energy storage device. However, this scheme needs to overcome the high-pressure environment of the deep sea to ensure the pipeline is sealed. In addition, seawater is highly corrosive and can easily corrode the delicate battery components and circulation pipelines inside the energy storage device. This not only shortens the service life of the equipment, but may also cause safety hazards such as leaks, making it difficult to meet the long-term stable operation requirements of underwater energy storage.

[0006] Thirdly, the cooling pipeline is arranged close to the energy storage cabin body shell, and heat dissipation is realized by indirect contact between the cabin body shell and the water body. However, the cabin body shell is usually thick to ensure the pressure bearing capacity, and the contact area between the pipeline and the water body is limited, the heat exchange path is long, the efficiency is very low, and the high heat generated during battery operation cannot be dissipated, which easily leads to heat accumulation in the cabin and causes battery overheating failure.

[0007] In addition, impurities (such as silt, microorganisms, etc.) commonly existing in underwater water bodies are easy to adhere to the exposed heat dissipation pipe wall surface, form a heat insulation layer to hinder heat exchange, further weaken the effect of the existing heat dissipation scheme, and cause the underwater energy storage device to be in high temperature working condition for a long time, which seriously restricts the large-scale application of the underwater energy storage system and the process of ocean energy development. SUMMARY

[0008] Therefore, the technical problem to be solved by the present application is to overcome the problems of the existing heat dissipation scheme for underwater energy storage, such as large heat dissipation efficiency being restricted by water temperature, being easy to be corroded, low heat exchange efficiency, lack of precise monitoring and control, and unstable battery heat dissipation.

[0009] To solve the above technical problems, the present application provides a heat dissipation system applied to underwater energy storage, an underwater energy storage device and a heat dissipation method. The heat dissipation system comprises a heat exchanger adapted to the underwater environment and a circulating pipeline. The heat exchanger comprises at least a coil pipe for heat exchange with an external water body, and the coil pipe comprises a coil pipe water outlet end and a coil pipe water inlet end.

[0010] The circulating pipeline comprises a refrigerant circulating pipeline, a battery liquid cooling circulating pipeline and an external water body heat exchange circulating pipeline which work independently and cooperatively.

[0011] The refrigerant circulating pipeline is provided with a compressor, a liquid condensation heat exchange unit, an expansion valve and a liquid evaporation heat exchange unit which are connected in series, forming a heat dissipation circuit which realizes heat transfer by gasification heat absorption and liquefaction heat release of the refrigerant.

[0012] The battery liquid cooling circulating pipeline comprises a PACK liquid cooling plate for heat coupling with an energy storage battery PACK, a first pressure compensation element and a first fluid driving element. The PACK liquid cooling plate, the first pressure compensation element, the first fluid driving element and the liquid evaporation heat exchange unit are selectively connected in series by pipelines, forming a heat dissipation circuit for circulating battery cooling liquid, and realizing absorption of battery heat by heat exchange between the cooling liquid and the liquid evaporation heat exchange unit.

[0013] The external water body heat exchange circulation pipeline comprises a second pressure compensation element and a second fluid driving element, the coil pipe water outlet end, the second pressure compensation element, the second fluid driving element, the liquid condensation heat exchange unit and the coil pipe water inlet end are selectively connected in sequence by a pipeline to form a heat dissipation loop for heat exchange between heat exchange fluid and an external water body to release heat.

[0014] In an embodiment of the present application, the circulation pipeline further comprises a plurality of temperature sensors and a plurality of pressure sensors, which are arranged in the refrigerant circulation pipeline, the battery liquid cooling circulation pipeline and the external water body heat exchange circulation pipeline.

[0015] In an embodiment of the present application, the system further comprises a control module connected with the plurality of temperature sensors and the plurality of pressure sensors.

[0016] In an embodiment of the present application, the control module is connected with the compressor.

[0017] In an embodiment of the present application, the control module is connected with the first pressure compensation element and the second pressure compensation element.

[0018] In an embodiment of the present application, the control module is connected with the first fluid driving element and the second fluid driving element.

[0019] In an embodiment of the present application, the liquid condensation heat exchange unit and the liquid evaporation heat exchange unit are both stacked by a plurality of metal plates with corrugated structure, and there is a specified interval between adjacent metal plates to form a heat exchange channel.

[0020] In an embodiment of the present application, a fluid filter is further connected in series in the external water body heat exchange circulation pipeline, which is arranged between the second fluid driving element and the liquid condensation heat exchange unit to filter impurities in the heat exchange fluid.

[0021] Based on the same inventive principle, the present application further provides an underwater energy storage device comprising the heat dissipation system and a protective shell, wherein the heat exchanger is arranged in water and the circulation pipeline is arranged in the protective shell.

[0022] In an embodiment of the present application, the protective shell is provided with an energy storage water outlet end and an energy storage water inlet end, the liquid condensation heat exchange unit is connected with the coil pipe water inlet end through the energy storage water outlet end, and the second pressure compensation element is connected with the coil pipe water outlet end through the energy storage water inlet end.

[0023] In addition, the present application further provides a heat dissipation method applied to the heat dissipation system, which comprises:

[0024] constructing a first heat exchange loop, and circulating a first heat exchange medium in the loop under the action of a first driving force, the first heat exchange medium first flows through a region in direct thermal contact with the battery to absorb heat generated during operation of the battery, and then carries the heat to a first heat exchange region;

[0025] constructing a second heat exchange loop, and circulating a second heat exchange medium in the loop under the action of a second driving force, the second heat exchange medium first flows to a second heat exchange region to absorb heat, and then carries the heat to a heat dissipation region in direct thermal contact with seawater to release the heat through natural heat exchange with the seawater, and then returns to the second heat exchange region;

[0026] constructing a phase change heat exchange loop, and circulating a phase change medium in the loop along the following circulation path:

[0027] the phase change medium is first subjected to pressurization treatment to change into a high-temperature and high-pressure state, then flows to the second heat exchange region to exchange heat with the second heat exchange medium in the second heat exchange loop, changes into a high-pressure liquid state after releasing heat, and then is subjected to depressurization treatment to change into a low-temperature and low-pressure state, then flows to the first heat exchange region to exchange heat with the first heat exchange medium in the first heat exchange loop, changes into a low-pressure gaseous state after absorbing the heat carried by the first heat exchange medium, and then returns to the initial pressurization treatment link to complete the phase change cycle;

[0028] through the heat absorption and heat release processes of the phase change medium in the phase change heat exchange loop, the temperature of the first heat exchange medium is lowered and the temperature of the second heat exchange medium is raised, and then the heat generated by the battery is sequentially transferred to seawater through the first heat exchange medium, the phase change medium and the second heat exchange medium, and the heat dissipation of the underwater energy storage system is completed.

[0029] In an embodiment of the present application, the heat dissipation method further comprises the step of adjusting the output power of the pressurization treatment device according to the temperature change of the second heat exchange medium in the second heat exchange loop to control the circulation rate of the phase change medium in the phase change heat exchange loop, as follows:

[0030] a first data sampling period K is set, first temperature data of the second heat exchange medium flowing out of the second heat exchange region in the current sampling period k is obtained and second temperature data of the second heat exchange medium flowing back to the second heat exchange region after flowing through the seawater heat dissipation region ;

[0031] the first temperature data and the second temperature data are subjected to outlier rejection processing to obtain pre-processed first temperature data and second temperature data ;

[0032] According to the and the , the actual temperature difference of the second heat exchange medium in the seawater heat dissipation area is calculated : ;

[0033] According to the set target temperature of the second heat exchange medium after heat exchange and the preset target temperature difference of the second heat exchange medium in the seawater heat dissipation area , the deviation value of the actual return temperature of the second heat exchange medium from the preset target temperature is calculated and the deviation value of the actual temperature difference of the second heat exchange medium between the outlet and the return port of the second heat exchange area from the preset target temperature difference :

[0034] , ;

[0035] According to the and the , the comprehensive deviation value is obtained : , and is a weight parameter;

[0036] According to the comprehensive deviation value obtained by calculating in multiple continuous sampling periods, a power adjustment model is constructed, and its expression is:

[0037] ,

[0038] Among them, represents the theoretical power adjustment amount of the current sampling period k, is the comprehensive error value calculated in the current sampling period k, is the comprehensive error value calculated in the last sampling period of k, is the comprehensive error value calculated in the last two sampling periods of k; is a proportional coefficient, is an integral coefficient, is a differential coefficient;

[0039] According to the power adjustment model, the output power of the pressurizing treatment equipment is adjusted to control the circulation rate of the phase change medium in the phase change heat exchange circuit.

[0040] In an embodiment of the present application, the heat dissipation method further comprises the step of adjusting the pressure compensation strategy according to the obtained pressure data of each heat exchange circuit, as follows:

[0041] Set the second data sampling period N, obtain the pressure data of the first heat exchange circuit, the second heat exchange circuit and the phase change heat exchange circuit in the current sampling period n , filter the collected pressure data and remove outliers to obtain effective pressure data of each heat exchange circuit ;

[0042] Based on the preset safety pressure range of each heat exchange circuit , calculate the effective pressure data of each heat exchange circuit Pressure deviation relative to the corresponding safety pressure range :

[0043] When , ;

[0044] When , ;

[0045] When , ;

[0046] According to the effective pressure data of the current sampling period n And the effective pressure data of the last sampling period , calculate the pressure change rate per unit time : , Sampling interval;

[0047] According to the pressure deviation And the pressure change rate , the risk level of each heat exchange circuit is divided, and for different heat exchange circuit pressure abnormal types and corresponding risk levels, the appropriate pressure compensation action is performed.

[0048] In an embodiment of the present application, according to the pressure deviation And the pressure change rate , the method for dividing the risk level of each heat exchange circuit includes:

[0049] Set the first threshold th1 and the second threshold th2 of the pressure deviation , and the first threshold th3 and the second threshold th4 of the pressure change rate , wherein th1<th2, th3<th4;

[0050] When And , the corresponding heat exchange circuit is of low risk level;

[0051] When Or When the temperature of the battery cooling liquid is higher than the temperature of the seawater or river water, the corresponding heat exchange circuit is a high-risk level.

[0052] When the temperature of the battery cooling liquid is higher than the temperature of the seawater or river water, the corresponding heat exchange circuit is a high-risk level. When the temperature of the battery cooling liquid is higher than the temperature of the seawater or river water, the corresponding heat exchange circuit is a high-risk level. When the temperature of the battery cooling liquid is higher than the temperature of the seawater or river water, the corresponding heat exchange circuit is a high-risk level.

[0053] The above technical solutions of the present application have the following beneficial effects compared with the existing heat dissipation technology which only relies on a single liquid cooling pipeline and can only work when the temperature of seawater / river water is lower than the required cooling liquid temperature of the battery (20-25℃):

[0054] The underwater energy storage heat dissipation system proposed by the present application uses the physical principles of refrigerant gasification heat absorption and liquefaction heat release, and through the cooperative operation of three liquid cooling pipelines (refrigerant pipeline, battery liquid cooling plate pipeline, and external heat dissipation device pipeline), the whole process uses liquid heat exchange and does not have any air cooling components. Not only does it successfully realize the transfer of heat from low-temperature medium (battery cooling liquid) to high-temperature medium (seawater / river water with a temperature higher than 20-25℃), but it also breaks through the limitations of season and water depth on underwater energy storage heat dissipation, ensuring that the underwater energy storage system can work stably in any season and any water depth conditions. In addition, by adding elements to cope with thermal expansion and contraction and real-time monitoring system status in the relevant pipelines, the stability and reliability of system operation are further ensured. BRIEF DESCRIPTION OF DRAWINGS

[0055] In order to make the content of the present application more easily understood, the present application will be further described in detail below according to specific embodiments of the present application and in conjunction with the accompanying drawings.

[0056] Figure 1 is a structural schematic diagram of the existing underwater energy storage heat dissipation system;

[0057] Figure 2 is a structural schematic diagram of the underwater energy storage heat dissipation system provided in the embodiment of the present application;

[0058] Figure 3 is a specific structural schematic diagram of the underwater energy storage heat dissipation system provided in the embodiment of the present application;

[0059] Figure 4 is a connection schematic diagram of the circulation pipeline and the control module provided in the embodiment of the present application;

[0060] Description of the drawings: 1, heat exchanger; 11, coil; 2, protective shell; 21, circulating pump; 22, PACK cold plate; 23, energy storage water outlet; 24, energy storage water inlet; 25, expansion tank; 26, temperature sensor; 27, pressure sensor; 10, circulating pipeline; 101, refrigerant circulating pipeline; 1011, compressor; 1012, liquid condensation heat exchange unit; 1013, expansion valve; 1014, liquid evaporation heat exchange unit; 102, battery liquid cooling circulating pipeline; 1021, PACK liquid cooling plate; 1022, first pressure compensation element; 1023, first fluid driving element; 103, external water body heat exchange circulating pipeline; 1031, second pressure compensation element; 1032, second fluid driving element; 1033, fluid filter; 20, control module. DETAILED DESCRIPTION

[0061] The present application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the present application and implement it. The examples are not intended to limit the present application.

[0062] Reference Figure 2 and Figure 3 As shown in the drawings, the present application provides a heat dissipation system applied to underwater energy storage, which comprises a heat exchanger 1 adapted to underwater environment and a circulating pipeline 10; wherein the heat exchanger 1 at least comprises a coil 11 for heat exchange with external water body, which can be tens of meters or even hundreds of meters long. The coil 11 comprises a coil water outlet 111 and a coil water inlet 112;

[0063] The circulating pipeline 10 comprises a refrigerant circulating pipeline 101, a battery liquid cooling circulating pipeline 102 and an external water body heat exchange circulating pipeline 103 which work independently and cooperatively;

[0064] The refrigerant circulating pipeline 101 is configured with a compressor 1011, a liquid condensation heat exchange unit 1012, an expansion valve 1013 and a liquid evaporation heat exchange unit 1014 which are connected in series, forming a heat dissipation circuit which relies on the gasification heat absorption and liquefaction heat release of refrigerant to realize heat transfer;

[0065] The battery liquid cooling circulating pipeline 102 comprises a PACK liquid cooling plate 1021 for heat coupling with energy storage battery PACK, a first pressure compensation element 1022 and a first fluid driving element 1023, the PACK liquid cooling plate 1021, the first pressure compensation element 1022, the first fluid driving element 1023 and the liquid evaporation heat exchange unit 1014 are selectively connected in series through the pipeline, forming a heat dissipation circuit for circulating battery cooling liquid, and the heat absorption of battery is realized through the heat exchange between cooling liquid and the liquid evaporation heat exchange unit 1014;

[0066] The external water body heat exchange circulation pipeline 103 comprises a second pressure compensation element 1031 and a second fluid driving element 1032, and the coil water outlet end 111, the second pressure compensation element 1031, the second fluid driving element 1032, the liquid condensation heat exchange unit 1012 and the coil water inlet end 112 are selectively connected in sequence by pipelines to form a heat dissipation loop for heat exchange between the heat exchange fluid and the external water body to release heat.

[0067] Further, the refrigerant circulation pipeline 101 realizes the transfer of heat from the low-temperature medium (battery cooling liquid) to the high-temperature medium (external water body heat exchange fluid) by using the heat absorption of gasification and the heat release of liquefaction of the refrigerant.

[0068] Optionally, the compressor 1011 is selected from a high-pressure resistant type suitable for underwater use, which is used to compress the low-pressure gaseous refrigerant into high-temperature and high-pressure gas to provide power for the phase change cycle. The liquid condensation heat exchange unit 1012 and the liquid evaporation heat exchange unit 1014 are both stacked by multiple metal plates with corrugated structure made of materials such as aluminum alloy and titanium alloy. There is a specified interval (2-5 mm) between adjacent metal plates to form thin rectangular heat exchange channels, and the two media flow alternately in the channels to improve the heat exchange efficiency.

[0069] Optionally, the refrigerant in the refrigerant circulation pipeline 101 includes environmentally friendly refrigerants such as R32, R410A or R134a, which takes into account the heat exchange efficiency and environmental friendliness. R410A is suitable for conditions with large temperature difference, and R134a is suitable for scenes with high requirements for low-temperature stability.

[0070] Optionally, the battery liquid cooling circulation pipeline 102 directly absorbs the heat of the energy storage battery PACK through the cooling liquid and transfers the heat to the refrigerant circulation pipeline. Optionally, the first pressure compensation element 1022 is an expansion tank with a volume designed according to 10%-15% of the total volume of the pipeline, which is used to balance the pressure fluctuation of the pipeline caused by thermal expansion and contraction to avoid pipeline rupture. The first fluid driving element 1023 is selected from a corrosion-resistant circulating pump with a lift of 5-10 m and a flow rate adjusted according to the battery cooling demand (usually 10-20 L / min) to provide power for the cooling liquid circulation. The cooling liquid is selected from ethylene glycol aqueous solution with insulation and high and low temperature resistance, and the concentration is between 30%-50% to avoid the risk of electric leakage and adapt to the temperature range of -10℃ to 60℃ underwater.

[0071] Further, the external water body heat exchange circulation pipeline 103 transfers the heat released by the refrigerant to the external water body, completing the final discharge of heat. It also includes a fluid filter 1033 arranged between the second fluid driving element 1032 and the liquid condensation heat exchange unit 1012, with a filter core aperture of 5-10 μm, for filtering impurities in the heat exchange fluid to avoid clogging the heat exchange channel.

[0072] Optionally, in the external water body heat exchange circulation pipeline 103, the second pressure compensation element 1031 and the first pressure compensation element 1022 are selected as expansion tanks with parameters matched with the first pressure compensation element 1022. The second fluid driving element 1032 is selected as a large-flow corrosion-resistant circulating pump with a head of 8-15 m (adapted to the resistance of the coil 11) and a flow rate 20%-30% higher than that of the first fluid driving element 1023, to ensure that the heat exchange fluid fully carries away heat. The heat exchange fluid type can be selected as deionized water or antifreeze fluid compatible with the external water body. When the external water body is seawater, an inhibitor such as benzotriazole needs to be added to the fluid.

[0073] Further, to ensure stable operation of the system, the circulation pipeline 10 further includes a plurality of temperature sensors 26 and a plurality of pressure sensors 27 arranged in the refrigerant circulation pipeline 101, the battery liquid cooling circulation pipeline 102, and the external water body heat exchange circulation pipeline 103. Specifically, as shown in Figure 3 The plurality of temperature sensors 26 are arranged at the outlet of the PACK liquid cooling plate 1021, the inlet and outlet of the liquid evaporation heat exchange unit 1014, the inlet and outlet of the liquid condensation heat exchange unit 1012, and the inlet and outlet of the coil 11, respectively. The plurality of pressure sensors 27 are arranged at the inlet and outlet of the compressor 1011, the inlet and outlet of the first fluid driving element 1023, the inlet and outlet of the second fluid driving element 1032, and before and after the expansion valve 1013, respectively.

[0074] As shown in Figure 4 The system further includes a control module 20, which is a PLC programmable logic controller or an embedded chip such as the STM32H7 series, with functions of data acquisition, logic judgment, and execution control. The control module 20 is connected with the plurality of temperature sensors 26 and the plurality of pressure sensors 27. The control module 20 is connected with the compressor 1011, the first pressure compensation element 1022, the second pressure compensation element 1031, the first fluid driving element 1023, and the second fluid driving element 1032.

[0075] Based on the same inventive principle as the heat dissipation system, the application further provides an underwater energy storage device, comprising the heat dissipation system and a protective shell 2, the coil 11 of the heat exchanger 1 is placed in water outside the protective shell 2, and the circulating pipeline 10 is arranged in the protective shell 2.

[0076] Optionally, the protective shell 2 adopts a pressure-resistant metal shell, the design pressure is determined according to the underwater working depth (for example, 0.4 MPa design pressure corresponding to 30 m water depth), the energy storage water outlet end 23 and the energy storage water inlet end 24 are arranged on the shell, the liquid condensation heat exchange unit 1012 is connected to the coil water inlet end through the energy storage water outlet end 23, and the second pressure compensation element 1031 is connected to the coil water outlet end through the energy storage water inlet end 24.

[0077] In addition, the application further provides a heat dissipation method applied to the heat dissipation system, comprising:

[0078] A first heat exchange loop corresponding to the battery liquid cooling circulating pipeline 102 is constructed, a first fluid driving element 1023 is started, and a first driving force is provided. Under the action of the first driving force, the first heat exchange medium (i.e. battery cooling liquid) circulates and flows in the loop, and the circulation path is "PACK liquid cooling plate 1021→ first pressure compensation element 1022→ first fluid driving element 1023→ liquid evaporation heat exchange unit 1014→ PACK liquid cooling plate 1021": the battery cooling liquid first flows through the PACK liquid cooling plate 1021 which is in direct thermal contact with the battery, absorbs the heat generated in the working process of the battery, and the temperature rises to 25-30℃; then carries the heat to the first heat exchange area (i.e. liquid evaporation heat exchange unit 1014) for heat exchange with the phase change medium;

[0079] A second heat exchange loop corresponding to the external water body heat exchange circulating pipeline 103 is constructed, a second fluid driving element 1032 is started, and a second driving force is provided. Under the action of the second driving force, the second heat exchange medium (i.e. (external water body heat exchange fluid) circulates and flows in the loop, and the circulation path is: liquid condensation heat exchange unit 1012→ energy storage water outlet end 23→ coil 11→ energy storage water inlet end 24→ second pressure compensation element 1031→ second fluid driving element 1032→ fluid filter 1033→ liquid condensation heat exchange unit 1012: the second heat exchange medium first flows to the second heat exchange area (i.e. liquid condensation heat exchange unit 1012) to absorb the heat released by the phase change medium, and the temperature rises to 40-50℃, then carries the heat to the heat dissipation area (i.e. coil 11) which is in direct thermal contact with seawater, releases the heat to the external water body through natural heat exchange, and the temperature drops to 30-35℃; the second heat exchange medium after temperature drop returns to the liquid condensation heat exchange unit 1012 to complete the circulation;

[0080] A phase change heat exchange circuit corresponding to the refrigerant circulation pipeline 101 is constructed, and the control module 20 starts the compressor 1011 to make the phase change medium (i.e. refrigerant) flow in the circuit according to the following circulation path: compressor 1011→liquid condensation heat exchange unit 1012→expansion valve 1013→liquid evaporation heat exchange unit 1014→compressor 1011.

[0081] The compressor 1011 compresses the low-pressure gaseous refrigerant into high-temperature and high-pressure gas, and the temperature rises to 50-60℃; the high-temperature and high-pressure gaseous refrigerant flows to the liquid condensation heat exchange unit 1012, exchanges heat with the second heat exchange medium in the second heat exchange circuit, and is converted into high-pressure liquid after releasing heat, and the temperature drops to 40-45℃; the high-pressure liquid refrigerant is processed by the expansion valve 1013 to convert into low-temperature and low-pressure state, and the temperature drops to 5-10℃, and then flows to the liquid evaporation heat exchange unit 1014, exchanges heat with the first heat exchange medium in the first heat exchange circuit, and is converted into low-pressure gas after absorbing the heat of the battery carried by the first heat exchange medium, and the temperature rises to 15-20℃; the low-pressure gaseous refrigerant returns to the compressor 1011 to repeat the above phase change process;

[0082] Through the heat absorption and release process of the phase change medium in the phase change heat exchange circuit, the temperature of the first heat exchange medium is lowered and the temperature of the second heat exchange medium is raised, respectively, and then the heat generated by the battery is transmitted to the seawater through the first heat exchange medium, the phase change medium and the second heat exchange medium in turn, and the heat dissipation of the underwater energy storage system is completed.

[0083] Further, to ensure stable heat dissipation efficiency, the heat dissipation method further comprises the step of adjusting the output power of the pressurization processing device according to the temperature change of the second heat exchange medium in the second heat exchange circuit to control the circulation rate of the phase change medium in the phase change heat exchange circuit, as follows:

[0084] A first data sampling period K (usually 10-30s, adjusted according to working condition fluctuation) is set to obtain the first temperature data of the second heat exchange medium flowing out of the second heat exchange area in the current sampling period k And the second temperature data of the second heat exchange medium flowing through the seawater heat dissipation area and returning to the second heat exchange area ;

[0085] The first temperature data And the second temperature data are subjected to outlier rejection processing by using 3σ criterion to obtain the pre-processed first temperature data And second temperature data ;

[0086] According to the first temperature data And the second temperature data , the actual temperature difference of the second heat exchange medium in the seawater heat dissipation area (i.e. in the coil 11) is calculated : ;

[0087] the target temperature of the second heat exchange medium after heat exchange according to the setting (typically 30-35℃) and the preset target temperature difference of the second heat exchange medium in the seawater heat dissipation area (typically 10-15℃), the deviation value of the actual return temperature of the second heat exchange medium from the preset target temperature is calculated and the deviation value of the actual temperature difference of the second heat exchange medium between the outlet and the return port of the second heat exchange area from the preset target temperature difference :

[0088] , ;

[0089] according to the and the , the comprehensive deviation value is obtained : , and is a weight parameter; α is taken as 0.6-0.8, and β is taken as 0.2-0.4, and the return temperature stability is preferentially ensured;

[0090] According to the comprehensive deviation value calculated in multiple continuous sampling periods, a power adjustment model is constructed, and the expression is:

[0091] ,

[0092] wherein, represents the theoretical power adjustment amount of the current sampling period k, is the comprehensive error value calculated in the current sampling period k, is the comprehensive error value calculated in the last sampling period of k, is the comprehensive error value calculated in the last two sampling periods of k; is a proportional coefficient, and the value is 2-5; is an integral coefficient, and the value is 0.1-0.5; is a differential coefficient, and the value is 0.5-1.5; according to the actual working condition adjustment;

[0093] The control module 20 adjusts the output power of the pressurizing treatment equipment according to the power adjustment model to control the circulation rate of the phase change medium in the phase change heat exchange circuit: if is positive, it means that the return temperature is too high or the temperature difference is insufficient, the output power of the compressor 1011 is increased, the circulation rate of the phase change medium is improved, and the heat dissipation is enhanced; if is negative, the output power of the compressor 1011 is reduced to avoid energy waste.

[0094] Optionally, to avoid the phenomenon of overpressure or underpressure in the pipeline, the heat dissipation method further comprises the step of adjusting the pressure compensation strategy according to the obtained pressure data of each heat exchange circuit, as follows:

[0095] The second data sampling period N (usually 5-15s, the pressure change response is faster than the temperature) is set, and the pressure data of the first heat exchange circuit, the second heat exchange circuit and the phase change heat exchange circuit in the current sampling period n is obtained The collected pressure data is filtered for noise and outliers by using a moving average filter (with a window size of 3-5) combined with the 3σ criterion, to obtain the effective pressure data of each heat exchange circuit ;

[0096] Based on the preset safety pressure range of each heat exchange circuit : for the first heat exchange circuit (i.e. the battery liquid cooling circulation pipeline 102), , ; for the second heat exchange circuit (i.e. the external water body heat exchange circulation pipeline 103), , ; for the phase change heat exchange circuit (i.e. the refrigerant circulation pipeline 101), , .

[0097] The pressure deviation of the effective pressure data of each heat exchange circuit relative to the corresponding safety pressure range is calculated :

[0098] When , it indicates that the corresponding circuit is in an overpressure state, ;

[0099] When , it indicates that the corresponding circuit is in an underpressure state, ;

[0100] When , it indicates that the corresponding circuit is within the safety range, ;

[0101] And according to the effective pressure data of the current sampling period n and the effective pressure data of the last sampling period of the same circuit , the pressure change rate per unit time is calculated : , The sampling interval is N;

[0102] The control module 20 divides the risk level of each heat exchange circuit according to the pressure deviation and the pressure change rate , as follows:

[0103] The first threshold th1 and the second threshold th2 of the pressure deviation The first threshold th3 and the second threshold th4 of the pressure change rate , wherein th1 < th2, th3 < th4; th1 = 0.1 MPa, th2 = 0.2 MPa, th3 = 0.02 MPa / s, th4 = 0.05 MPa / s;

[0104] When and , the corresponding heat exchange circuit is of low risk level;

[0105] When or , the corresponding heat exchange circuit is of medium risk level;

[0106] When or , the corresponding heat exchange circuit is of high risk level;

[0107] For different types of pressure abnormalities of the heat exchange circuit and corresponding risk levels, the adaptive pressure compensation action is performed, as follows:

[0108] For the compensation strategy of the first heat exchange circuit, when the first heat exchange circuit is in an under-pressure state, the power of the first fluid driving element 1023 is increased, and the increase is positively correlated with the corresponding circuit pressure deviation , such as = 0.1 MPa, the power is increased by 10%; when the first heat exchange circuit is in an over-pressure state, the first pressure compensation element 1022 is turned on, and the power of the first fluid driving element 1023 is reduced, both of which are positively correlated with the corresponding circuit pressure deviation .

[0109] For the compensation strategy of the second heat exchange circuit, when it is in an under-pressure state, the power of the second fluid driving element 1032 is increased, and the increase is 5-10% higher than that of the first heat exchange circuit under the same deviation due to the greater resistance of the coil 11; when it is in an over-pressure state, the second pressure compensation element 1031 is turned on, and the power of the second fluid driving element 1032 is reduced, both of which are positively correlated with the corresponding circuit pressure deviation ;

[0110] For the compensation strategy of the phase change heat exchange circuit, when the outlet of the compressor is over-pressured, the pressurizing side relief valve is turned on, and the power of the second fluid driving element 1032 is simultaneously increased to enhance the heat absorption of the second heat exchange medium; when the outlet of the expansion valve 1013 is under-pressured, the opening of the expansion valve is adjusted, and the adjustment is positively correlated with the corresponding circuit pressure deviation The determination plays a role in reducing the refrigerant flow.

[0111] After the pressure compensation action is performed, the effective pressure data of each heat exchange loop is continuously collected , and whether the pressure is in the corresponding safe pressure range is monitored; if the pressure is in the safe range, the current compensation state is maintained; if the pressure is not in the corresponding safe pressure range, the compensation action amplitude is adjusted according to the current pressure deviation calculated , the compensation action is repeatedly performed until the pressure of each heat exchange loop is stabilized in the safe operation range.

[0112] Obviously, the above embodiments are only examples for clearly illustrating, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A heat dissipation method for underwater energy storage, characterized in that, include: A first heat exchange circuit is constructed, and a first heat exchange medium is circulated within the circuit under the action of a first driving force. The first heat exchange medium first flows through the area that is in direct thermal contact with the battery, absorbs the heat generated during the operation of the battery, and then carries the heat to the first heat exchange area. A second heat exchange loop is constructed, and the second heat exchange medium circulates within the loop under the action of the second driving force. The second heat exchange medium first flows to the second heat exchange area to absorb heat, and then carries the heat through the heat dissipation area that is in direct thermal contact with seawater. The heat is released through natural heat exchange with seawater, and then flows back to the second heat exchange area. Construct a phase change heat transfer loop, and allow the phase change medium to flow within the loop according to the following circulation path: The phase change medium is first pressurized by a pressurization device to become a high-temperature and high-pressure state, and then flows to the second heat exchange zone to exchange heat with the second heat exchange medium in the second heat exchange circuit. After releasing heat, it becomes a high-pressure liquid. The high-pressure liquid phase change medium is depressurized by the pressurization device to become a low-temperature and low-pressure state, and then flows to the first heat exchange zone to exchange heat with the first heat exchange medium in the first heat exchange circuit. After absorbing the battery heat carried by the first heat exchange medium, it becomes a low-pressure gas. The low-pressure gas phase change medium flows back to the initial pressurization process to complete the phase change cycle. The output power of the pressurization processing device is adjusted according to the temperature change of the second heat exchange medium in the second heat exchange circuit, so as to control the circulation rate of the phase change medium in the phase change heat exchange circuit. Through the heat absorption and heat release processes of the phase change medium in the phase change heat transfer circuit, the cooling of the first heat exchange medium and the heating of the second heat exchange medium are achieved respectively, thereby transferring the heat generated by the battery to the seawater in sequence through the first heat exchange medium, the phase change medium and the second heat exchange medium, thus completing the heat dissipation of the underwater energy storage system. The method for adjusting the output power of the pressurized processing equipment according to the temperature change of the second heat exchange medium in the second heat exchange circuit to control the circulation rate of the phase change medium in the phase change heat exchange circuit is as follows: Set a first data sampling period K, and obtain the first temperature data of the second heat exchange medium flowing out of the second heat exchange region during the current sampling period k. The second temperature data after the second heat exchange medium flows through the seawater heat dissipation area and returns to the second heat exchange area. ; For the first temperature data and the second temperature data Outlier removal was performed to obtain the preprocessed first temperature data. Second temperature data ; According to the above and stated Calculate the actual temperature difference of the second heat exchange medium in the seawater heat dissipation zone. : ; Based on the target temperature after heat exchange with the second heat exchange medium. The preset target temperature difference between the second heat exchange medium and the seawater heat dissipation zone Calculate the deviation between the actual reflux temperature of the second heat exchange medium and the preset target temperature. The deviation between the actual temperature difference between the outlet and return port of the second heat exchange medium in the second heat exchange zone and the preset target temperature difference. : ， ； According to the above and stated The overall deviation value is obtained. : , and These are weight parameters; Based on the comprehensive deviation value calculated from multiple consecutive sampling periods, a power regulation model is constructed, the expression of which is: ， in, This represents the theoretical power adjustment amount for the current sampling period k. The comprehensive error value is calculated for the current sampling period k. The comprehensive error value is calculated for the previous sampling period of k. The combined error value is calculated for the two sampling periods above k. This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients; The output power of the pressurized processing equipment is adjusted according to the power regulation model to control the circulation rate of the phase change medium in the phase change heat transfer circuit.

2. The heat dissipation method according to claim 1, characterized in that, The heat dissipation method further includes the step of adjusting the pressure compensation strategy based on the acquired pressure data of each heat exchange loop, as follows: Set a second data sampling period N, and acquire the pressure data of the first heat exchange loop, the second heat exchange loop, and the phase change heat exchange loop during the current sampling period n. The collected pressure data is subjected to noise filtering and outlier removal to obtain the effective pressure data for each heat exchange loop. ; Based on the preset safety pressure range of each heat exchange loop Calculate the effective pressure data for each heat exchange loop. Pressure deviation relative to the corresponding safe pressure range : when hour, ; when hour, ; when hour, ; And based on the effective pressure data of the current sampling period n and the effective pressure data of the previous sampling period Calculate the rate of change of pressure per unit time. : , The sampling interval; According to the pressure deviation and the pressure change rate Each heat exchange loop is classified into risk levels, and appropriate pressure compensation actions are performed for different types of pressure anomalies and corresponding risk levels of heat exchange loops.

3. The heat dissipation method according to claim 2, characterized in that, According to the pressure deviation and the pressure change rate Methods for classifying the risk levels of each heat exchange loop include: Set the pressure deviation The first threshold th1 and the second threshold th2, and the pressure change rate The first threshold th3 and the second threshold th4, where th1 <th2,th3<th4; when and At that time, the corresponding heat exchange circuit is classified as low-risk. when or At that time, the corresponding heat exchange circuit is classified as medium risk. when or At that time, the corresponding heat exchange circuit is classified as high-risk.

4. A heat dissipation system for implementing the method as described in any one of claims 1 to 3, characterized in that, include: A heat exchanger, circulation pipeline, and control module adapted to underwater environments; wherein the heat exchanger includes at least a coil for heat exchange with external water, the coil including a coil outlet and a coil inlet; The circulation pipeline includes multiple temperature sensors, as well as independent and cooperative refrigerant circulation pipeline, battery liquid cooling circulation pipeline, and external water heat exchange circulation pipeline; the control module is connected to multiple temperature sensors. The refrigerant circulation pipeline is equipped with a pressurization device, a liquid condensation heat exchange unit, an expansion valve, and a liquid evaporation heat exchange unit connected in series, forming a heat dissipation circuit that relies on the heat absorption of refrigerant vaporization and the heat release of refrigerant to achieve heat transfer; the pressurization device is connected to the control module; The battery liquid cooling circulation pipeline includes a PACK liquid cooling plate for thermal coupling with the energy storage battery PACK, a first pressure compensation element, and a first fluid drive element. The PACK liquid cooling plate, the first pressure compensation element, the first fluid drive element, and the liquid evaporation heat exchange unit are selectively connected in sequence through the pipeline to form a heat dissipation circuit for circulating battery coolant. The battery heat is absorbed through heat exchange between the coolant and the liquid evaporation heat exchange unit. The external water heat exchange circulation pipeline includes a second pressure compensation element and a second fluid drive element. The coil outlet, the second pressure compensation element, the second fluid drive element, the liquid condensation heat exchange unit, and the coil inlet are selectively connected in sequence through the pipeline to form a heat dissipation circuit for the heat exchange fluid to exchange heat with the external water body to release heat.

5. The heat dissipation system for underwater energy storage according to claim 4, characterized in that, The circulation pipeline also includes multiple pressure sensors, which are installed in the refrigerant circulation pipeline, the battery liquid cooling circulation pipeline, and the external water heat exchange circulation pipeline.

6. The heat dissipation system for underwater energy storage according to claim 5, characterized in that, The control module is connected to multiple pressure sensors.

7. The heat dissipation system for underwater energy storage according to claim 4, characterized in that, The control module is connected to the first pressure compensation element and the second pressure compensation element.

8. The heat dissipation system for underwater energy storage according to claim 4, characterized in that, The control module is connected to the first fluid drive element and the second fluid drive element.

9. The heat dissipation system for underwater energy storage according to claim 4, characterized in that, Both the liquid condensation heat exchange unit and the liquid evaporation heat exchange unit are composed of multiple corrugated metal plates stacked together, with a specified interval between adjacent metal plates to form a heat exchange channel.

10. The heat dissipation system for underwater energy storage according to claim 4, characterized in that, A fluid filter is also connected in series in the external water heat exchange circulation pipeline. The fluid filter is located between the second fluid drive element and the liquid condensation heat exchange unit and is used to filter impurities in the heat exchange fluid.

11. An underwater energy storage device, characterized in that, The device includes the heat dissipation system and protective housing as described in any one of claims 4 to 10, wherein the heat exchanger is placed in water and the circulation pipeline is disposed within the protective housing.

12. The underwater energy storage device according to claim 11, characterized in that, The protective housing is provided with an energy storage outlet and an energy storage inlet. The liquid condensation heat exchange unit is connected to the coil inlet through the outlet of the energy storage device. The second pressure compensation element is connected to the coil outlet through the energy storage inlet.

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