Immersion liquid cooling device of net-forming type energy storage converter and use method

Abstract

The invention discloses an immersion liquid cooling device of a net-forming type energy storage converter and a use method, and belongs to the technical field of high-voltage cascade energy storage, the device comprises a power module cooling unit, a first heat exchanger, a second heat exchanger and a liquid storage tank; cooling liquid is arranged in the power module cooling unit, the power module is soaked in the cooling liquid, and direct heat exchange of the power module is carried out. The power module cooling unit is connected with the first heat exchanger, the first heat exchanger is connected with one end of the liquid storage tank, the other end of the liquid storage tank is connected with the second heat exchanger, and cooling liquid flows into the second heat exchanger from the liquid storage tank for indirect heat exchange of electronic elements in the converter; and the second heat exchanger is connected with the power module cooling unit to form an immersion liquid cooling device. Through indirect heat exchange and direct heat exchange, the heat dissipation problem that heat consumption is increased due to short-time multi-time overload of the net-forming type energy storage converter is solved, and the problems that an existing converter is low in heat dissipation efficiency, complex in system, low in reliability and the like in cooling are solved.

Description

Technical Field

[0001] This patent belongs to the field of high-voltage cascade energy storage technology, and specifically, relates to an immersion liquid cooling device and use method for a grid-type energy storage inverter. Background Art

[0002] With the in-depth construction of the new power system, the proportion of renewable energy in the power system is increasing. By the end of 2023, the installed capacity of wind power and solar power will account for one-third of the national power installed capacity, and the proportion of power generation will also reach 15%. With the continuous increase in the proportion of wind power and photovoltaic power generation, the operation mode of the power system is undergoing profound changes. Especially in Tibet, Xinjiang, Gansu, Ningxia and other regions with a high proportion of renewable energy and relatively weak power grid foundation, as well as the sending end of large renewable energy bases built in deserts, Gobi and deserts, there are many challenges, such as too low short-circuit ratio of multiple stations, broadband oscillation, insufficient inertia level, and poor voltage and power angle stability.

[0003] In this context, grid-based energy storage technology came into being and became the focus of the industry. Grid-based energy storage, as the name implies, refers to energy storage systems that can build and maintain output voltage and frequency, operate with voltage source characteristics, and actively support the grid when the grid fails. Grid-based energy storage must have a certain short-term overload capacity. When a transient fault occurs in the power grid, grid-based energy storage can actively support the grid by providing short-term overload capacity to ensure the stable operation of the power system. At present, the industry generally requires energy storage systems to provide 10 seconds of support capacity when overloaded by 3 times. Although discussions on the duration of short-term overloads are still ongoing, providing short-term overload capacity has become the main difference between grid-based energy storage and conventional grid-based energy storage, and it is also an important factor affecting equipment prices.

[0004] The common heat dissipation methods of energy storage converters are currently forced air cooling and cold plate liquid cooling. However, both heat dissipation methods have complex structures, large space occupation, and limited heat flux density. In order to adapt to the subsequent continuous capacity increase of energy storage systems and solve the higher heat flux density that will exist in the future, the immersion liquid cooling device is very necessary for the research and development of energy storage converters. Prior art document 1 (CN115715075A) discloses an immersion cooling box, including a sealed box body for installing a heating device inside, the sealed box body is provided with a liquid inlet and a liquid outlet, the liquid inlet is used to input the insulating coolant into the sealed box body, and the liquid outlet is used to discharge the insulating coolant out of the sealed box body; the sealed box body is also provided with an input conductor and an output conductor electrically connected to the heating device respectively; the gaps between the input conductor and the output conductor and the sealed box body are sealed respectively. However, this prior art can only solve the heat dissipation of the power module. The heat dissipation of other electronic components in the equipment cabinet needs to be solved by other heat dissipation systems, and another set of heat exchange equipment and power equipment needs to be added. The system is complex and occupies a large space. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the present invention provides an immersion liquid cooling device applied to a grid-type energy storage inverter. Through indirect liquid cooling heat exchange and direct liquid cooling heat exchange, the heat dissipation problem of increased heat consumption caused by short-term multiple overload of the grid-type energy storage inverter is solved, and the problems of low heat dissipation efficiency, complex system, low reliability, etc. in the existing inverter cooling scheme are improved.

[0006] The present invention adopts the following technical solution.

[0007] The first aspect of the present invention discloses an immersion liquid cooling device for a grid-type energy storage converter, comprising: a power module cooling unit, a first heat exchanger, a second heat exchanger and a liquid storage tank;

[0008] The power module cooling unit contains a coolant inside, and the power module of the grid-type energy storage converter is immersed in the coolant of the power module cooling unit to perform direct contact heat exchange on the power module;

[0009] One end of the power module cooling unit is connected to the first heat exchanger, and the first heat exchanger is connected to one end of the liquid storage tank. When the device is not started, the coolant is static in the entire device;

[0010] The other end of the liquid storage tank is connected to one end of the second heat exchanger. When the device is started, the coolant flows from the liquid storage tank into the second heat exchanger to perform indirect contact heat exchange with the electronic components in the converter.

[0011] The other end of the second heat exchanger is connected to the power module cooling unit to form an immersion liquid cooling device for the grid-type energy storage converter.

[0012] Preferably, the device comprises a liquid connecting pipeline, and the liquid outlet of the power module cooling unit is connected to the liquid inlet of the first heat exchanger through the liquid connecting pipeline.

[0013] Preferably, the device comprises a liquid pump, which is arranged between the liquid storage tank and the second heat exchanger. The coolant flows from the liquid storage tank into the second heat exchanger through the pressurization of the liquid pump.

[0014] Preferably, the device comprises a quick-connect connector, and the second heat exchanger is connected to the power module cooling unit via the quick-connect connector.

[0015] Preferably, the first heat exchanger is arranged outside the equipment cabinet of the energy storage inverter and is connected to the external environment. An external circulation fan is provided on one side of the first heat exchanger, and heat is exchanged between the low-temperature air outside the cabinet and the first heat exchanger through the external circulation fan.

[0016] Preferably, the second heat exchanger is arranged in an equipment cabinet, and an in-cabinet circulation fan is arranged on one side of the equipment cabinet, so that the hot air in the cabinet exchanges heat with the second heat exchanger through the in-cabinet circulation fan.

[0017] Preferably, the coolant is electronic fluorinated liquid.

[0018] The second aspect of the present invention discloses an immersion liquid cooling method for a grid-type energy storage converter, based on the immersion liquid cooling device for the grid-type energy storage converter, comprising the following steps:

[0019] The energy storage converter is started, the electronic components are heated, and the immersion liquid cooling device is started;

[0020] The liquid pump in the immersion liquid cooling device is started, and the coolant in the liquid storage tank flows in the immersion liquid cooling device along the liquid connecting pipeline to perform indirect contact heat exchange and direct contact heat exchange;

[0021] After the heat exchange is completed, the coolant flows back to the liquid pump, completing a flow heat exchange cycle.

[0022] Preferably, the indirect heat exchange is as follows: the coolant flows along the connecting pipeline to the second heat exchanger, and indirect heat exchange is performed with the hot air in the cabinet at the second heat exchanger, so that the coolant temperature increases and the air temperature in the cabinet decreases.

[0023] Preferably, the direct heat exchange is: the coolant flowing out of the second heat exchanger flows into the power module cooling unit, the heat of the power module is directly exchanged with the coolant, the heat is transferred to the coolant, the coolant temperature increases, and the power module temperature decreases.

[0024] Compared with the prior art, the beneficial effects of the present invention include at least:

[0025] The present invention makes full use of the sensible heat exchange characteristics of the coolant to perform indirect and direct heat exchange with units with different heat dissipation requirements of the energy storage converter, thereby enhancing the heat dissipation effect;

[0026] The energy storage converter includes power modules, transformers, filters, supporting capacitors, fuses, reactors, transformers, AC and DC switches and other electronic components. The present invention solves the heat dissipation requirements of all the above components through a set of cooling devices, has a simple structure, occupies a small space, and has high safety and reliability.

[0027] The immersion liquid cooling and air cooling heat dissipation adopted by the present invention both utilize the sensible heat exchange characteristics of the coolant. The immersion liquid cooling is direct contact heat exchange, and the forced air cooling is indirect contact cooling. In comparison, the direct contact heat dissipation performance is better and the heat exchange can be realized faster. In the power industry, there is a situation where the power increases instantaneously and the heat consumption increases suddenly. Therefore, the immersion liquid cooling is adopted for the heat dissipation of the power module in the present invention, which has a good instantaneous cooling effect and can cope with the situation where the heat consumption increases suddenly.

[0028] The present invention adopts air cooling to dissipate heat for other electronic components except power modules, and utilizes the sensible heat characteristics of coolant in different temperature ranges. The low-temperature coolant indirectly cools the air in the cabinet through a heat exchanger and a fan, thereby solving the heat dissipation requirements of other heat-generating components in the equipment cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a structural diagram of the immersion liquid cooling device of the present invention;

[0030] Figure 2 is a flow chart of a method for using the immersion liquid cooling device of the present invention;

[0031] In the figure: 1-power module cooling unit; 2-first heat exchanger; 3-second heat exchanger; 4-liquid connecting pipeline; 5-liquid storage tank; 6-liquid pump; 7-quick plug connector; 8-circulation fan outside the cabinet; 9-circulation fan inside the cabinet. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in this application are only embodiments of a part of the present invention, rather than all embodiments. Based on the spirit of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0033] Embodiment 1 of the present invention provides an immersion liquid cooling device for a grid-type energy storage inverter, comprising: a power module cooling unit 1, a first heat exchanger 2, a second heat exchanger 3, a liquid connecting pipeline 4, a liquid storage tank 5, a liquid pump 6, a quick-connect connector 7, an external circulation fan 8 and an internal circulation fan 9.

[0034] The power module cooling unit 1 contains a coolant inside, and the power module of the grid-type energy storage converter is immersed in the coolant of the power module cooling unit 1, and the power module cooling unit 1 is connected to the first heat exchanger 2;

[0035] The cooling liquid can be selected as electronic fluorinated liquid.

[0036] The liquid outlet of the power module cooling unit 1 is connected to the liquid inlet of the first heat exchanger 2 via a liquid connecting pipeline 4 .

[0037] The liquid outlet of the first heat exchanger 2 is connected to the liquid storage tank 5. When the cooling device is not started, the coolant is static in the entire device.

[0038] A liquid pump 6 is provided between the liquid storage tank 5 and the second heat exchanger 3. When the cooling device is started, the coolant is pressurized by the liquid pump 6, and flows from the liquid storage tank 5 into the second heat exchanger 3.

[0039] The second heat exchanger 3 is connected to the power module cooling unit 1 via a quick-connect connector 7 to form an immersion liquid cooling device.

[0040] The quick-connect connector 7 ensures that there is no liquid leakage in the pipeline of the power module refrigeration unit 1 during connection and removal.

[0041] The first heat exchanger 2 and the second heat exchanger 3 are both provided with fans. The first heat exchanger 2 is arranged outside the equipment cabinet and communicates with the external environment. The external circulation fan 8 causes the low-temperature air outside the cabinet to exchange heat with the first heat exchanger 2. The temperature of the high-temperature coolant in the heat exchanger decreases. After the low-temperature air outside the cabinet flows through the heat exchanger, the temperature increases and is dispersed into the external environment.

[0042] The second heat exchanger 3 is arranged in the equipment cabinet, and the circulating fan 9 in the cabinet promotes heat exchange between the hot air in the cabinet and the second heat exchanger. The temperature of the coolant in the second heat exchanger 3 increases, and the temperature of the air in the cabinet decreases after passing through the heat exchanger, thereby dissipating heat and cooling other electronic components in the cabinet.

[0043] During use, the heating element is immersed in the medium-temperature coolant of the power module cooling unit 1. The medium-temperature coolant directly contacts the heating element for heat exchange in the power module cooling unit 1. The medium-temperature coolant absorbs heat and heats up to become high-temperature coolant. The high-temperature coolant flows to the first heat exchanger 2 through the liquid connecting pipeline, and indirectly exchanges heat with the low-temperature air outside the cabinet at the first heat exchanger 2. The low-temperature air outside the cabinet absorbs heat and heats up to become high-temperature air, and the high-temperature coolant releases heat and cools down to become low-temperature coolant.

[0044] For example, in practical applications, assuming that the maximum external ambient temperature is 35°C, the high-temperature coolant in the first heat exchanger 2 is cooled to 40°C. As long as the low-temperature coolant in the second heat exchanger 3 ensures that the hot air in the cabinet is cooled to 55°C, the demand can be met.

[0045] The low-temperature coolant flows to the liquid storage tank 5 through the liquid connecting pipeline. Under the action of the liquid pump 6, the low-temperature coolant flows to the second heat exchanger 3, where it exchanges heat indirectly with the high-temperature air in the cabinet. The hot air in the cabinet releases heat, and the low-temperature coolant absorbs heat and heats up to medium-temperature coolant.

[0046] Air cooling in the cabinet: under the action of the circulating fan 9 in the cabinet, the low-temperature air in the cabinet is responsible for the heat dissipation and cooling of other components in the cabinet;

[0047] The medium-temperature coolant flows into the power module cooling unit 1 through the quick-connect connector 7 along the connecting pipeline, and directly contacts and cools the power module immersed therein. The coolant absorbs heat and the temperature rises, and then flows into the heat exchanger 1 again, thus completing a complete heat absorption and heat release cycle.

[0048] This embodiment mainly relies on the sensible heat of the coolant to cool down all the electronic components in the cabinet. The types of heat exchange in the cabinet mainly include direct contact heat exchange, indirect contact heat exchange and forced air cooling. Indirect contact heat exchange occurs at the first heat exchanger 2 and the second heat exchanger 3, direct contact heat exchange occurs at the power module cooling unit 1, and the low-temperature air in the cabinet cools other heating components by forced air cooling.

[0049] Embodiment 2 of the present invention provides an immersion cooling method for a grid-type energy storage converter, comprising the following steps:

[0050] Step 1: The energy storage converter is started, the electronic components are heated, and the cooling device is started;

[0051] Step 2, the liquid pump 6 is started, and the coolant in the cooling device begins to flow along the liquid connecting pipeline;

[0052] Step 3, the low-temperature coolant obtains power from the liquid pump 6, flows along the connecting pipeline to the second heat exchanger 3, and generates indirect heat exchange with the hot air in the cabinet at the second heat exchanger 3, and the temperature of the low-temperature coolant rises to medium-temperature coolant;

[0053] Step 4, the medium-temperature coolant flows into the power module cooling unit 1 through the flow pipeline and the quick-connect connector 7, and the heat of the power module is directly exchanged with the coolant, and the heat is transferred to the coolant, and the coolant is heated to the high-temperature coolant and flows out of the power module cooling unit 1;

[0054] Step 5: The high-temperature coolant flows to the first heat exchanger 2 through the connecting pipe 4. The first heat exchanger is located outside the energy storage converter cabinet. The high-temperature coolant in the first heat exchanger 2 exchanges heat with the environment here, transferring heat to the ambient air. After the high-temperature coolant flows through the first heat exchanger, the temperature is reduced to the ambient temperature or slightly higher than the ambient temperature, and flows to the liquid storage tank 5 through the connecting pipe;

[0055] Step 6, the low-temperature coolant flows to the liquid pump 6 to be pressurized again, and thus a complete flow heat exchange cycle is completed.

[0056] Compared with the prior art, the beneficial effects of the present invention include at least:

[0057] The present invention makes full use of the sensible heat exchange characteristics of the coolant to perform indirect and direct heat exchange with units with different heat dissipation requirements of the energy storage converter, thereby enhancing the heat dissipation effect;

[0058] The energy storage converter includes power modules, transformers, filters, supporting capacitors, fuses, reactors, transformers, AC and DC switches and other electronic components. The present invention solves the heat dissipation requirements of all the above components through a set of cooling devices, has a simple structure, occupies a small space, and has high safety and reliability.

[0059] The immersion liquid cooling and air cooling used in the present invention both utilize the sensible heat exchange characteristics of the coolant. The immersion liquid cooling is direct contact heat exchange, and the forced air cooling is indirect contact cooling. In comparison, the direct contact heat dissipation has better heat dissipation performance and can achieve heat exchange faster. In the power industry, there is a situation where the power increases instantaneously and the heat consumption increases suddenly. Therefore, the present invention adopts immersion liquid cooling for the heat dissipation of the power module, which has a good instant cooling effect and can cope with the situation of a sudden increase in heat consumption.

[0060] The present invention adopts air cooling to dissipate heat for other electronic components except power modules, and utilizes the sensible heat characteristics of coolant in different temperature ranges. The low-temperature coolant indirectly cools the air in the cabinet through a heat exchanger and a fan, thereby solving the heat dissipation requirements of other heat-generating components in the equipment cabinet.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An immersion liquid cooling device for a grid-type energy storage converter, characterized in that: include: A power module cooling unit (1), a first heat exchanger (2), a second heat exchanger (3) and a liquid storage tank (5); The power module cooling unit (1) contains cooling liquid inside, and the power module of the grid-type energy storage converter is immersed in the cooling liquid of the power module cooling unit (1) to perform direct contact heat exchange on the power module; One end of the power module cooling unit (1) is connected to the first heat exchanger (2), and the first heat exchanger (2) is connected to one end of the liquid storage tank (5). When the device is not started, the coolant is static in the entire device. The other end of the liquid storage tank (5) is connected to one end of the second heat exchanger (3). When the device is started, the coolant flows from the liquid storage tank (5) into the second heat exchanger (3) to perform indirect contact heat exchange with the electronic components in the converter. The other end of the second heat exchanger (3) is connected to the power module cooling unit (1), forming an immersion liquid cooling device for the grid-type energy storage converter.

2. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1 is characterized in that: The device comprises a liquid connecting pipeline (4), and the liquid outlet of the power module cooling unit (1) is connected to the liquid inlet of the first heat exchanger (2) through the liquid connecting pipeline (4).

3. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1 is characterized in that: The device comprises a liquid pump (6), which is arranged between the liquid storage tank (5) and the second heat exchanger (3). Through the pressurization of the liquid pump (6), the coolant flows from the liquid storage tank (5) into the second heat exchanger (3).

4. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1 is characterized in that: The device comprises a quick-connect connector (7), and the second heat exchanger (3) is connected to the power module cooling unit (1) via the quick-connect connector (7).

5. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1 is characterized in that: The first heat exchanger (2) is arranged outside the equipment cabinet of the energy storage inverter and is in communication with the external environment. An external circulation fan (8) is arranged on one side of the first heat exchanger (2). The external circulation fan (8) is used to exchange heat between the low-temperature air outside the cabinet and the first heat exchanger (2).

6. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1, characterized in that: The second heat exchanger (3) is arranged in an equipment cabinet, and an in-cabinet circulation fan (9) is arranged on one side thereof, and the in-cabinet circulation fan (9) is used to exchange heat between the hot air in the cabinet and the second heat exchanger (3).

7. The immersion liquid cooling device of a grid-type energy storage converter according to claim 1 is characterized in that: The cooling liquid is an electronic fluorinated liquid.

8. An immersion liquid cooling method for a grid-type energy storage converter, based on an immersion liquid cooling device for a grid-type energy storage converter according to any one of claims 1 to 7, characterized in that: The following steps are involved: The energy storage converter is started, the electronic components are heated, and the immersion liquid cooling device is started; The liquid pump (6) in the immersion liquid cooling device is started, and the cooling liquid in the liquid storage tank (5) flows along the liquid connecting pipeline in the immersion liquid cooling device to perform indirect contact heat exchange and direct contact heat exchange; After the heat exchange is completed, the coolant flows back to the liquid pump (6), completing a flow heat exchange cycle.

9. The immersion liquid cooling method of a grid-type energy storage converter according to claim 8, characterized in that: The indirect heat exchange is as follows: the coolant flows along the connecting pipeline to the second heat exchanger (3), and indirect heat exchange is generated with the hot air in the cabinet at the second heat exchanger (3), so that the temperature of the coolant increases and the temperature of the air in the cabinet decreases.

10. The immersion liquid cooling method of a grid-type energy storage converter according to claim 8, characterized in that: The direct heat exchange is as follows: the coolant flowing out of the second heat exchanger (3) flows into the power module cooling unit (1), the heat of the power module is directly exchanged with the coolant, the heat is transferred to the coolant, the temperature of the coolant increases, and the temperature of the power module decreases.

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