Thermal management system of energy storage unit and control method of thermal management system

Abstract

The invention belongs to the technical field of energy storage equipment, and discloses an energy storage unit heat management system and a control method thereof.The energy storage unit heat management system comprises a main loop, a refrigerant loop and an auxiliary loop; the refrigerant loop comprises a compressor, a condenser and a cooling fan assembly. The auxiliary loop comprises a heat dissipation water tank which is located on the side, away from the heat dissipation fan assembly, of the condenser. Wherein the heat dissipation fan assembly comprises a first fan unit and a second fan unit, and the first fan unit corresponds to the heat dissipation water tank in position. The heat dissipation fan assembly is mainly composed of the first fan unit and used in cooperation with the second fan unit, power distribution of the heat dissipation fan assembly is optimized, and the energy efficiency ratio is increased on the premise that the system is kept stable.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage equipment, and in particular to a thermal management system of an energy storage unit and a control method thereof. Background Art

[0002] The existing thermal management system of energy storage units mainly uses a composite circuit consisting of a heat sink circuit and a compressor refrigeration circuit to cool the energy storage unit. When the ambient temperature drops to medium or low temperatures, the compressor in the compressor refrigeration circuit and the fan in the heat sink circuit will start at the same time for joint refrigeration, while reducing the compressor speed and maintaining the refrigeration efficiency. The fan in the existing heat sink circuit basically runs at full power after startup to avoid problems such as system instability caused by fan speed reduction. However, the fan runs at a high speed, has high noise and high power, and the system energy consumption remains high, making it difficult to reduce the overall energy efficiency of the system. Summary of the invention

[0003] The purpose of the present invention is to provide a thermal management system for an energy storage unit, optimize the power distribution of the heat dissipation fan assembly, and improve the energy efficiency ratio while maintaining system stability.

[0004] To achieve this object, the present invention adopts the following technical solutions: a thermal management system of an energy storage unit, comprising a main circuit, a refrigerant circuit and an auxiliary circuit, the main circuit comprising a heat exchanger; the refrigerant circuit comprising a compressor, a condenser and a heat dissipation fan assembly, the compressor and the condenser are connected end to end through the heat exchanger, and the heat dissipation fan assembly is laid on one side of the condenser; the auxiliary circuit is connected in parallel with the main circuit, the auxiliary circuit comprises a heat dissipation water tank, and the heat dissipation water tank is located on the side of the condenser away from the heat dissipation fan assembly; wherein the heat dissipation fan assembly comprises a first fan group and a second fan group, the first fan group corresponds to the position of the heat dissipation water tank, the first fan group and the second fan group cooperate to cool the refrigerant in the condenser; and / or, cool the coolant in the heat dissipation water tank.

[0005] Preferably, the second fan unit includes a first auxiliary fan unit located above the first fan unit; and / or a second auxiliary fan unit located below the first fan unit.

[0006] Preferably, the first fan group includes a plurality of variable frequency fans, and the plurality of variable frequency fans are arranged at intervals in the horizontal direction.

[0007] Another object of the present invention is to provide a control method for a thermal management system of an energy storage unit, intelligently control the operation of a heat dissipation fan assembly, optimize the power distribution of the heat dissipation fan assembly, and improve the energy efficiency ratio while maintaining system stability.

[0008] To achieve this object, the present invention adopts the following technical solutions: a control method for a thermal management system of an energy storage unit, comprising the following steps: presetting a first temperature, a second temperature and a system pressure, wherein the second temperature is less than the first temperature; obtaining the ambient temperature, and comparing the ambient temperature with the first temperature and the second temperature; if the ambient temperature is less than the first temperature and greater than the second temperature, controlling the thermal management system of the energy storage unit to enter a combined cooling mode; in the combined cooling mode, adjusting the rotation speeds of the first fan unit and the second fan unit so that the high pressure of the compressor is greater than or equal to the system pressure.

[0009] Preferably, the adjusting the rotational speeds of the first fan group and the second fan group specifically comprises the following steps: gradually reducing the rotational speed of the second fan group to a minimum rotational speed; obtaining the high-pressure pressure, and comparing the high-pressure pressure with the system pressure; if the high-pressure pressure is lower than the system pressure, shutting down the second fan group, and gradually reducing the rotational speed of the first fan group until the high-pressure pressure of the compressor is greater than or equal to the system pressure.

[0010] Preferably, after gradually reducing the rotational speed of the first fan group, the following steps are also included: controlling the rotational speed of the first fan group to a minimum rotational speed; obtaining the high-pressure pressure again, and comparing the high-pressure pressure obtained for the second time with the system pressure; if the high-pressure pressure obtained for the second time is less than the system pressure, controlling the thermal management system of the energy storage unit to switch from the combined refrigeration mode to the natural refrigeration mode; in the natural refrigeration mode, turning off the compressor and the first fan group.

[0011] Preferably, before gradually reducing the rotational speed of the second fan unit to the minimum rotational speed, the following steps are also included: presetting the refrigeration temperature; obtaining the water outlet temperature of the refrigerant in the main circuit, and comparing the water outlet temperature with the refrigeration temperature; if the water outlet temperature is greater than the refrigeration temperature, controlling the first fan unit to operate at a preset rotational speed, and gradually increasing the rotational speed of the second fan unit until the water outlet temperature is less than or equal to the refrigeration temperature.

[0012] Preferably, after comparing the ambient temperature with the first temperature and the second temperature, the following steps are also included: if the ambient temperature is less than or equal to the second temperature, controlling the energy storage unit thermal management system to enter the FC cooling mode; in the FC cooling mode, turning off the compressor, and controlling the speeds of the second fan unit and the first fan unit to decrease sequentially.

[0013] Preferably, the controlling the rotational speeds of the second fan group and the first fan group to be reduced sequentially specifically comprises the following steps: gradually reducing the rotational speed of the second fan group to a minimum rotational speed, and controlling the second fan group to operate at the minimum rotational speed; gradually reducing the rotational speed of the first fan group to a minimum rotational speed, and controlling the first fan group to operate at the minimum rotational speed.

[0014] Preferably, after comparing the ambient temperature with the first temperature and the second temperature, the following steps are also included: if the ambient temperature is greater than or equal to the first temperature, controlling the energy storage unit thermal management system to enter the AC cooling mode; in the AC cooling mode, controlling the first fan group and the second fan group to run at the same speed.

[0015] The beneficial effects of the present invention are as follows: a heat dissipation fan assembly is provided, the heat dissipation fan assembly is composed of a first fan group and a second fan group, the first fan group in the heat dissipation fan assembly corresponds to the position of the heat dissipation water tank, when the heat dissipation fan assembly is running, the first fan group can take away most of the heat at the heat dissipation water tank, and the second fan group can take away the remaining heat, the heat dissipation fan assembly is mainly composed of the first fan group, and is used in conjunction with the second fan group to replace the original high-power fan, optimize the power distribution of the heat dissipation fan assembly, and improve the energy efficiency ratio while maintaining system stability.

[0016] The present invention also provides a control method for a fan group thermal management system, which can reduce the rotation speeds of the first fan group and the second fan group in turn according to the ambient temperature, reduce the power of the heat dissipation fan component while maintaining system stability, and improve the overall energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a system schematic diagram of the energy storage unit thermal management system of the present invention;

[0018] Figure 2 is a schematic structural diagram of a heat dissipation fan assembly of the present invention;

[0019] Figure 3 is a flow chart of a control method of a thermal management system of an energy storage unit according to the present invention;

[0020] Figure 4 yes Figure 1 A flow chart of adjusting the rotation speed of the first fan unit and the second fan unit;

[0021] Figure 5 yes Figure 4 Flow chart after gradually reducing the speed of the first fan unit;

[0022] Figure 6 yes Figure 4 A flow chart before gradually reducing the speed of the second fan unit to the minimum speed;

[0023] Figure 7 yes Figure 4 A flow chart after comparing the ambient temperature with the first temperature and the second temperature;

[0024] Figure 8 yes Figure 7 A flow chart of controlling the rotation speeds of the second fan group and the first fan group to decrease in sequence;

[0025] Fig. 9 yes Figure 4 Flow chart after comparing the ambient temperature with the first temperature and the second temperature.

[0026] In the figure:

[0027] 100, main circuit; 110, energy storage unit; 111, first temperature sensor; 112, first pressure sensor; 113, second temperature sensor; 114, second pressure sensor; 120, water storage tank; 121, water pump; 122, sight glass; 123, liquid filling valve; 130, heat exchanger; 140, heater; 150, booster pump unit;

[0028] 200, refrigerant circuit; 210, compressor; 211, third temperature sensor; 212, fourth temperature sensor; 220, condenser; 230, gas-liquid separator; 240, heat dissipation fan assembly; 241, first fan unit; 242, second fan unit;

[0029] 300, auxiliary circuit; 310, cooling water tank; 311, electric-controlled three-way valve; 320, fifth temperature sensor. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0031] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0033] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0034] Reference Figure 1 and Figure 2 As shown, a thermal management system for an energy storage unit provided according to an embodiment of the present application includes a main circuit 100, a refrigerant circuit 200 and an auxiliary circuit 300. In addition, the thermal management system for the energy storage unit also includes an ambient temperature sensor capable of detecting ambient temperature.

[0035] Specifically, the main circuit 100 includes an energy storage unit 110, a water storage tank 120, a heat exchanger 130, a heater 140 and a booster pump unit 150. The heat exchanger 130 is provided with a first heat exchange channel and a second heat exchange channel capable of heat exchange. The water outlet of the energy storage unit 110 and the water outlet of the water storage tank 120 are connected to the water inlet of the booster pump unit 150 through a tee. A water pump 121 is provided at the water outlet of the water storage tank 120. The water outlet of the booster pump unit 150 is connected to the water inlet of the heater 140 and one end of the first heat exchange channel through a tee. An openable and closable electric-controlled three-way valve 311 is provided at the water inlet of the heater 140. The water outlet of the heater 140 and the other end of the first heat exchange channel are connected to the water inlet of the water storage tank 120 and the water inlet of the energy storage unit 110 through two parallel tees. Among them, the pipeline at the water inlet end of the energy storage unit 110 is provided with a first temperature sensor 111 and a first pressure sensor 112, the pipeline at the water outlet end of the energy storage unit 110 is provided with a second temperature sensor 113 and a second pressure sensor 114, and the pipeline at the water inlet end of the booster pump group 150 is provided with a liquid filling valve 123 connected to an external coolant source.

[0036] When the main circuit 100 is working, the electrically controlled three-way valve 311 is closed, and the coolant in the main circuit 100 flows out from the energy storage unit 110, mixes with the coolant extracted by the water pump 121 and enters the booster pump group 150. The booster pump group 150 passes the coolant into the first heat exchange channel. The coolant enters the energy storage unit 110 after heat exchange and cooling in the first heat exchange channel, and then performs heat exchange with the energy storage unit 110 to realize refrigeration of the energy storage unit 110.

[0037] The refrigerant circuit 200 includes a compressor 210, a condenser 220 and a heat dissipation fan assembly 240. The compressor 210 and the condenser 220 are connected end to end through the heat exchanger 130. Specifically, the outlet of the compressor 210 is connected to the inlet of the condenser 220. The outlet of the condenser 220 is connected to one end of the second heat exchange channel through the gas-liquid separator 230. The other end of the second heat exchange channel is connected to the inlet of the compressor 210. The heat dissipation fan assembly 240 is laid on one side of the condenser 220. Among them, the pipeline at the inlet of the compressor 210 is provided with an integrated third temperature sensor 211 and a third pressure sensor, and the pipeline at the outlet of the compressor 210 is provided with an integrated fourth temperature sensor 212 and a fourth pressure sensor.

[0038] When the refrigerant circuit 200 is working, the compressor 210 sucks the refrigerant in the second heat exchange channel, heats and pressurizes the refrigerant, and then passes it into the condenser 220. The high-temperature and high-pressure refrigerant releases heat and reduces pressure in the condenser 220. The low-temperature and low-pressure refrigerant in the condenser 220 flows into the second heat exchange channel and exchanges heat with the coolant in the first heat exchange channel, thereby greatly reducing the temperature of the coolant and improving the cooling efficiency of the coolant. Optionally, the first heat exchange channel and the second heat exchange channel are in opposite directions to increase the heat exchange efficiency between the refrigerant and the cooling heat.

[0039] The water inlet of the auxiliary circuit 300 is connected to the electric three-way valve 311, and the water outlet of the auxiliary circuit 300 is connected to the water outlet of the heater 140 through the three-way valve. At this time, the auxiliary circuit 300 is connected in parallel with the main circuit 100. The auxiliary circuit 300 includes a heat dissipation water tank 310 and a fifth temperature sensor 320 inserted into the heat dissipation water tank 310. The heat dissipation water tank 310 is connected in parallel with the heater 140. The heat dissipation water tank 310 is a plate-shaped container with a plurality of heat dissipation fin structures on the surface. The heat dissipation water tank 310 is located on the side of the condenser 220 away from the heat dissipation fan assembly 240. When the heat dissipation fan assembly 240 is in operation, the condenser 220 and the heat dissipation water tank 310 can be cooled at the same time.

[0040] When the auxiliary circuit 300 is working, the electrically controlled three-way valve 311 connects the boosting pump group 150 and the heat dissipation water tank 310 and isolates the boosting pump group 150 and the heater 140. The boosting pump group 150 passes part of the coolant into the heat dissipation water tank 310. After the coolant exchanges heat with the air in the heat dissipation water tank 310, it is mixed with the coolant flowing out of the first heat exchange channel and enters the energy storage unit 110, thereby realizing refrigeration of the energy storage unit 110.

[0041] When the weather is cold, the ambient temperature around the system is very low, and the energy storage unit 110 is difficult to operate normally, the electrically controlled three-way valve 311 isolates the booster pump group 150 and the heat dissipation water tank 310 and connects the booster pump group 150 and the heater 140. The booster pump group 150 passes part of the coolant into the heater 140. After the coolant is heated by the heater 140, it mixes with the coolant flowing out of the first heat exchange channel and enters the energy storage unit 110, heating the energy storage unit 110, achieving heating of the energy storage unit 110, and ensuring the normal operation of the energy storage unit 110. Among them, the heater 140 can be set as a plurality of parallel PTC electric heating wires to simplify the structure of the heater 140, which will not be repeated here.

[0042] The heat dissipation fan assembly 240 includes a first fan unit 241 and a second fan unit 242, and the first fan unit 241 and the second fan unit 242 are basically spread over the surface of the condenser 220. The first fan unit 241 corresponds to the position of the heat dissipation water tank 310 to ensure the cooling capacity of the first fan unit 241 to the heat dissipation water tank 310. Exemplarily, when the heat dissipation water tank 310 is located in the middle of the condenser 220, the first fan unit 241 is also installed in the middle of the condenser 220. When the heat dissipation water tank 310 is located in the upper part of the condenser 220, the installation position of the first fan unit 241 is relatively upward. When the heat dissipation water tank 310 is located in the lower part of the condenser 220, the installation position of the first fan unit 241 is relatively downward. This is specially explained here to avoid misunderstanding.

[0043] The first fan unit 241 and the second fan unit 242 cooperate to refrigerate one of the refrigerant in the condenser 220 or the coolant in the heat dissipation water tank 310, or to refrigerate both the refrigerant in the condenser 220 and the coolant in the heat dissipation water tank 310. Specifically, when the compressor 210 is running and the three-way valve closes the water inlet end of the heat dissipation water tank 310, the first fan unit 241 and the second fan unit 242 refrigerate the refrigerant in the condenser 220. When the compressor 210 is running and the three-way valve opens the water inlet end of the heat dissipation water tank 310, the first fan unit 241 and the second fan unit 242 refrigerate both the refrigerant in the condenser 220 and the coolant in the heat dissipation water tank 310. When the compressor 210 is turned off and the three-way valve opens the water inlet end of the cooling water tank 310, the first fan group 241 and the second fan group 242 cool the coolant in the cooling water tank 310. Since the ambient temperature gradually decreases during the operation of the system, at this time, the coolant has a sufficient heat exchange temperature difference between the cooling water tank 310 and the heat exchanger 130 for heat exchange, and the coolant temperature gradually decreases. The first fan group 241 and the second fan group 242 can gradually reduce the rotation speed according to the change of the ambient temperature, thereby reducing power consumption.

[0044] It can be understood that by setting up the heat dissipation fan assembly 240, the heat dissipation fan assembly 240 is composed of a first fan group 241 and a second fan group 242. The first fan group 241 in the heat dissipation fan assembly 240 corresponds to the position of the heat dissipation water tank 310. When the heat dissipation fan assembly 240 is running, the first fan group 241 can take away most of the heat from the heat dissipation water tank 310, and the second fan group 242 can take away the remaining heat. The heat dissipation fan assembly 240 is mainly composed of the first fan group 241, and is used in conjunction with the second fan group 242 to replace the original high-power fan, optimize the power distribution of the heat dissipation fan assembly 240, and the first fan group 241 and the second fan group 242 can gradually reduce the rotation speed at low temperature, thereby improving the overall energy efficiency ratio of the system while maintaining system stability (that is, the coolant remains at a sufficiently low temperature for heat exchange with the energy storage system). In addition, the heat dissipation water tank 310 is located on the side of the condenser 220 away from the heat dissipation fan assembly 240, that is, the heat dissipation fan assembly 240 and the condenser 220 are arranged in sequence along the air outlet direction of the heat dissipation fan assembly 240, which can avoid the heat generated by the condenser 220 from exchanging heat with the heat dissipation water tank 310, affecting the heat exchange efficiency of the heat dissipation water tank 310, and effectively improving the structural rationality of the system.

[0045] It should be noted that the ambient temperature sensor, the first temperature sensor 111, the second temperature sensor 113, the third temperature sensor 211, the fourth temperature sensor 212, the fifth temperature sensor 320, the first pressure sensor 112, the second pressure sensor 114, the third pressure sensor, the fourth pressure sensor, the compressor 210, the water pump 121, the booster pump group 150, the electric control three-way valve 311 and the heat dissipation fan assembly 240 in the energy storage unit thermal management system are all electrically connected or communicatively connected to the same control system. The user can set different cooling modes and the conditions required to trigger the corresponding cooling modes through the control system.

[0046] Reference Figure 2 As shown, it can be understood that when the first fan group 241 is located at a lower position, the second fan group 242 includes a first auxiliary fan group located on the upper side of the first fan group 241. When the first fan group 241 is located at an upper position, the second fan group 242 includes a second auxiliary fan group located at the lower side of the first fan group 241. When the first fan group 241 is located in the middle of the condenser 220, the second fan group 242 includes a first auxiliary fan group and a second auxiliary fan group located at the upper and lower sides of the first fan group 241.

[0047] The position of the second fan unit 242 is reasonably arranged according to the position of the first fan unit 241 to ensure that the first fan unit 241 and the second fan unit 242 can cover the surface of the condenser 220, thereby ensuring the cooling performance of the heat dissipation fan assembly 240 on the condenser 220.

[0048] Furthermore, the first fan group 241 includes a plurality of variable frequency fans, and the plurality of variable frequency fans are arranged at intervals in the horizontal direction.

[0049] The first fan unit 241 is configured as a plurality of horizontally arranged variable frequency fans, so that the first fan unit 241 can be conveniently controlled to adjust the speed while ensuring that the first fan unit 241 has sufficient air volume for cooling. It should be noted that due to installation space limitations and in order to avoid a substantial increase in power during the operation of the first fan unit 241, the number of first fan units 241 is usually no more than three, that is, two or three first fan units 241 can be arranged according to the air volume requirements, which will not be described in detail here. The composition of the second fan unit 242 can refer to the above description of the first fan unit 241, which will not be described in detail here.

[0050] Reference Figure 1 As shown, it can be understood that the water tank 120 is also provided with a liquid level display, which is used to display the content of the coolant in the water tank 120, so as to facilitate the user to replenish the coolant in time through the liquid filling valve 123, and further improve the stability of the system operation. Optionally, the liquid level display can be a transparent liquid sight tube 122 provided on the side wall of the water tank 120, or a probe extending into the interior of the water tank 120, etc., which will not be described in detail here.

[0051] Reference Figure 3 As shown, a control method for a thermal management system of an energy storage unit provided in an embodiment of the present application includes:

[0052] S100, presetting a first temperature, a second temperature and a system pressure, wherein the second temperature is lower than the first temperature;

[0053] S200, obtaining the ambient temperature, and comparing the ambient temperature with the first temperature and the second temperature;

[0054] S300, if the ambient temperature is less than the first temperature and greater than the second temperature, the energy storage unit thermal management system is controlled to enter a combined cooling mode, a combined cooling mode and a cooling mode in which the cooling fan assembly 240, the main circuit 100, the refrigerant circuit 200 and the auxiliary circuit 300 are operated simultaneously;

[0055] S400, in the combined cooling mode, adjusting the rotation speeds of the first fan unit 241 and the second fan unit 242 so that the high pressure of the compressor 210 is greater than or equal to the system pressure.

[0056] It is understandable that in the initial state, the user can set the first temperature and the second temperature, which are the ambient temperatures of the coolant at the heat dissipation water tank 310 and the heat exchanger 130 with a certain heat exchange temperature difference, and the temperature that can be naturally cooled. Exemplarily, the first temperature can be set to 16°C, 15°C, 14°C, etc., and the second temperature can be set to -4°C, -5°C, -6°C, etc., which will not be repeated here. When the ambient temperature is between the first temperature and the second temperature, the coolant can be heat exchanged with the low-temperature air at the heat dissipation water tank 310 and the heat exchanger 130, without the compressor 210 and the heat dissipation fan assembly 240 running at full power. At this time, the compressor 210 slows down, the heat dissipation fan assembly 240 appropriately adjusts the speed, and controls the high pressure of the compressor 210 to be greater than or equal to the system pressure, so that the compressor 210, under the premise of maintaining high pressure stability and stable refrigeration effect, uses the automatically speed-regulated heat dissipation fan assembly 240 and external cold air to assist in refrigerating the coolant in the heat dissipation water tank 310, optimizes the overall power distribution of the system, and improves the overall energy efficiency ratio of the system.

[0057] It should be added that the system pressure of the compressor 210 is the average pressure when the compressor 210 is operating stably. The system pressure is an inherent parameter determined by the structure of the compressor 210. The user can set the corresponding system pressure according to the actual output of the compressor 210, which will not be elaborated here.

[0058] It should also be added that the detection and judgment of the ambient temperature is real-time, that is, the system continuously performs temperature detection during operation. When the ambient temperature is not between the first temperature and the second temperature, the system will exit the combined cooling mode and switch to other modes to ensure the flexibility of system control.

[0059] Reference Figure 4 As shown, step S400 includes:

[0060] S410, gradually reducing the rotation speed of the second fan unit 242 to a minimum rotation speed;

[0061] S420, obtaining the high pressure, and comparing the high pressure with the system pressure;

[0062] S430, if the high pressure is lower than the system pressure, the second fan unit 242 is turned off, and the rotation speed of the first fan unit 241 is gradually reduced until the high pressure of the compressor 210 is greater than or equal to the system pressure.

[0063] It should be noted that the rotation speeds of the first fan group 241 and the second fan group 242 can be represented by the duty cycle of the fan. For example, the minimum rotation speed of the second fan group 242 is 16%, that is, the variable frequency fan in the second fan group 242 runs at a minimum duty cycle of 16%. The maximum rotation speed of the second fan group 242 is 30%, that is, the variable frequency fan in the second fan group 242 runs at a maximum duty cycle of 30%.

[0064] It is understandable that when the system just enters the joint refrigeration mode, the rotation speeds of the first fan unit 241 and the second fan unit 242 are relatively high, the heat exchange efficiency of the refrigerant in the condenser 220 is relatively high, and the high pressure of the compressor 210 is relatively low. At this time, the rotation speed of the second fan unit 242, which has a relatively small impact on the heat dissipation water tank 310, can be reduced first. During the deceleration process of the second fan unit 242, if the high pressure of the compressor 210 is stably greater than or equal to the system pressure, the second fan unit 242 and the first fan unit 241 both continue to operate at the current rotation speed. If the rotation speed of the second fan unit 242 is reduced to the minimum, the high pressure of the compressor 210 is still stable or less than the system pressure, and the high pressure of the compressor 210 is unstable, at this time, continue to reduce the rotation speed of the second fan unit 242 until the high pressure of the compressor 210 is stably greater than or equal to the system pressure. First slowing down and shutting down the second fan unit 242 and then slowing down the first fan unit 241 can minimize the impact of the first and second fan units 241 and 242 on the cooling water tank 310 during the deceleration process, further optimize power distribution, and effectively improve the stability of system operation.

[0065] Reference Figure 5 As shown, after step S430, the following steps are included:

[0066] S431, controlling the rotation speed of the first fan unit 241 to a minimum rotation speed;

[0067] S432, obtaining the high pressure pressure again, and comparing the high pressure pressure obtained for the second time with the system pressure;

[0068] S433, if the high pressure obtained for the second time is less than the system pressure, the energy storage unit thermal management system is controlled to switch from the combined cooling mode to the natural cooling mode, the natural cooling mode and the main circuit 100 and the auxiliary circuit 300 are running at the same time, and the refrigerant circuit 200 and the heat dissipation fan assembly 240 are both turned off.

[0069] S434, in the natural cooling mode, turning off the compressor 210 and the first fan unit 241.

[0070] It is understandable that when the rotation speed of the second fan unit 242 is decelerated to the minimum speed, the high pressure of the compressor 210 is still relatively low, indicating that the ambient temperature is very low at this time, and the coolant can basically meet the system cooling requirements by exchanging heat with the cold air in the heat dissipation water tank 310 and the heat exchanger 130. At this time, the first fan unit 241 (the second fan unit 242 has been turned off before) and the compressor 210 can be turned off to avoid idling of the heat dissipation fan assembly 240 and the compressor 210, and use the heat dissipation water tank 310 and the heat exchanger 130 for natural cooling to reduce energy loss.

[0071] Reference Figure 6 As shown, before step S410, the following steps are included:

[0072] S411, preset cooling temperature;

[0073] S412, obtaining the outlet water temperature of the refrigerant in the main circuit 100, and comparing the outlet water temperature with the refrigeration temperature;

[0074] S413, if the outlet water temperature is greater than the cooling temperature, control the first fan unit 241 to operate at a preset speed, and gradually increase the speed of the second fan unit 242 until the outlet water temperature is less than or equal to the cooling temperature.

[0075] It is understandable that the refrigeration temperature, i.e., the coolant, can stabilize the temperature of the refrigeration energy storage system. Exemplarily, the refrigeration temperature can be set to 20°C, 19°C, 18°C, etc. The outlet water temperature is the temperature of the coolant when it enters the energy storage system, i.e., the actual temperature of the coolant detected by the first temperature sensor 111. When the system just enters the joint refrigeration mode, the speeds of the compressor 210 and the heat dissipation fan assembly will both decrease, which may cause the outlet water temperature of the refrigerant in the main circuit 100 to rise. At this time, the speed of the first fan unit 241, which has a greater impact on the heat dissipation water tank 310, is first increased, and then the speed of the second fan unit 242 is increased, thereby improving the heat exchange efficiency of the refrigerant in the condenser 220 and the coolant in the heat dissipation water tank 310, reducing the outlet water temperature of the refrigerant in the main circuit 100, and ensuring that the outlet water temperature is stable and less than or equal to the refrigeration temperature, thereby ensuring that the system can also stably refrigerate when the mode is switched, and further improving the stability of the system operation.

[0076] It should be added that the preset speed of the first fan unit 241, i.e., the actual speed of the first fan unit 241 when the cooling effect of the refrigerant circuit 200 and the auxiliary circuit 300 is the same or close to that of the refrigerant circuit 200 alone at high power. In other words, when the compressor 210 is running alone at a high speed and the auxiliary circuit 300 is closed, the outlet water temperature of the refrigerant in the main circuit 100 is set to a. When the compressor 210 is running and the auxiliary circuit 300 is turned on, the first fan unit 241 simultaneously dissipates heat to the refrigerant in the condenser 220 and the coolant in the heat dissipation water tank 310, so that the outlet water temperature of the refrigerant in the main circuit 100 is equal to or close to a (with a deviation range of ±0.5°C), the speed of the first fan unit 241 is the preset speed. The preset speed is the maximum speed of the first fan unit 241 in the joint cooling mode, and the maximum speed of the second fan unit 242 is less than the preset speed. For example, the preset speed of the first fan unit 241 can be set to 50%, and the preset speed of the second fan unit 242 can be set to 30%. When the system is not in the combined cooling mode, the speed of the first fan unit 241 can be greater than the preset speed.

[0077] Reference Figure 7 As shown, after step S200, the following steps are included:

[0078] S210, if the ambient temperature is less than or equal to the second temperature, control the energy storage unit thermal management system to enter the FC cooling mode, the FC cooling mode is a cooling mode in which the heat dissipation fan assembly 240, the main circuit 100 and the auxiliary circuit 300 are running at the same time, and the refrigerant circuit 200 is closed;

[0079] S220, in the FC cooling mode, the compressor 210 is turned off, and the rotation speeds of the second fan unit 242 and the first fan unit 241 are controlled to decrease in sequence.

[0080] It is understandable that the ambient temperature is less than or equal to the second temperature, that is, the system is in a low temperature environment, at which time, the coolant has a sufficient temperature difference for heat exchange at the heat dissipation water tank 310 and the heat exchanger 130. By turning off the compressor 210 and controlling the speeds of the second fan unit 242 and the first fan unit 241 to decrease in sequence, the system loss is reduced, the low temperature environment is reasonably used for refrigeration, and the overall energy efficiency ratio of the system is further improved.

[0081] Reference Figure 8 As shown, step S220 includes:

[0082] S221, gradually reducing the rotation speed of the second fan unit 242 to the minimum rotation speed, and controlling the second fan unit 242 to operate at the minimum rotation speed;

[0083] S222, gradually reducing the rotation speed of the first fan unit 241 to a minimum rotation speed, and controlling the first fan unit 241 to operate at the minimum rotation speed.

[0084] It can be understood that after the rotation speeds of the second fan group 242 and the first fan group 241 are reduced to the minimum rotation speed in turn, the minimum rotation speed is maintained to ensure that the cold air has a certain flow rate in the heat dissipation water tank 310, thereby improving the heat exchange efficiency of the coolant in the heat dissipation water tank 310, and enhancing the cooling effect of the system under the premise of improving the energy efficiency ratio.

[0085] Reference Fig. 9 As shown, after step S200, the following steps are also included:

[0086] S230, if the ambient temperature is greater than or equal to the first temperature, control the energy storage unit thermal management system to enter the AC cooling mode, the AC cooling mode is a cooling mode in which the heat dissipation fan assembly 240, the main circuit 100 and the refrigerant circuit 200 are running at the same time, and the auxiliary circuit 300 is closed;

[0087] S240, in the AC cooling mode, controlling the first fan unit 241 and the second fan unit 242 to run at the same speed.

[0088] It is understandable that the ambient temperature is greater than or equal to the first temperature, indicating that the system is in a medium-high temperature environment, and the system is mainly cooled by the compressor 210 and the condenser 220 in the refrigerant circuit 200. At this time, the first fan unit 241 and the second fan unit 242 run synchronously at a high speed. Exemplarily, the speed of the first fan unit 241 is set to 70%. While facilitating system control, the heat dissipation efficiency of the heat dissipation fan assembly 240 is improved, so that the system can quickly cool down and enter the joint refrigeration mode to ensure the refrigeration effect of the system.

[0089] It should be added that after the system enters the natural cooling mode for a period of time, as the energy storage system continues to release heat, the coolant and ambient temperature will gradually rise. When the outlet water temperature is greater than the cooling temperature, the system switches back to the combined cooling mode, that is, the first fan unit 241 is started first, and gradually increases from the minimum speed to the maximum speed, and then the second fan unit 242 is started, and the second fan unit 242 also gradually increases from the minimum speed to the maximum speed, and then the compressor 210 is started until the outlet water temperature is less than or equal to the cooling temperature again, and the system re-determines the ambient temperature and starts a new control cycle.

[0090] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The thermal management system of the energy storage unit is characterized by: include: A main circuit (100) includes a heat exchanger (130); A refrigerant circuit (200) comprises a compressor (210), a condenser (220) and a heat dissipation fan assembly (240), wherein the compressor (210) and the condenser (220) are connected end to end via the heat exchanger (130), and the heat dissipation fan assembly (240) is laid on one side of the condenser (220); An auxiliary circuit (300) is connected in parallel with the main circuit (100), the auxiliary circuit (300) comprising a heat dissipation water tank (310), the heat dissipation water tank (310) being located on a side of the condenser (220) away from the heat dissipation fan assembly (240); The heat dissipation fan assembly (240) comprises a first fan group (241) and a second fan group (242); the first fan group (241) corresponds to the position of the heat dissipation water tank (310); the first fan group (241) and the second fan group (242) cooperate to dissipate the refrigerant in the condenser (220); And / or, the coolant in the heat dissipation water tank (310) is used for refrigeration.

2. The energy storage unit thermal management system according to claim 1, characterized in that: The second fan unit (242) includes a first auxiliary fan unit located on the upper side of the first fan unit (241); and / or a second auxiliary fan unit located on the lower side of the first fan unit (241).

3. The thermal management system of the energy storage unit according to claim 1, characterized in that: The first fan group (241) includes a plurality of variable frequency fans, and the plurality of variable frequency fans are arranged at intervals in the horizontal direction.

4. A control method for a thermal management system of an energy storage unit, applied to the thermal management system of an energy storage unit according to any one of claims 1 to 3, characterized in that: The following steps are involved: Preset a first temperature, a second temperature and a system pressure, wherein the second temperature is lower than the first temperature; Acquire the ambient temperature, and compare the ambient temperature with the first temperature and the second temperature; If the ambient temperature is lower than the first temperature and higher than the second temperature, controlling the thermal management system of the energy storage unit to enter a joint cooling mode; In the combined refrigeration mode, the rotation speeds of the first fan unit (241) and the second fan unit (242) are adjusted so that the high pressure of the compressor (210) is greater than or equal to the system pressure.

5. The control method of the thermal management system of the energy storage unit according to claim 4, characterized in that: The step of adjusting the rotation speeds of the first fan group (241) and the second fan group (242) specifically comprises the following steps: gradually reducing the rotation speed of the second fan unit (242) to a minimum rotation speed; Obtaining the high pressure, and comparing the high pressure with the system pressure; If the high pressure is lower than the system pressure, the second fan unit (242) is turned off, and the rotation speed of the first fan unit (241) is gradually reduced until the high pressure of the compressor (210) is greater than or equal to the system pressure.

6. The control method of the thermal management system of the energy storage unit according to claim 5, characterized in that: After gradually reducing the rotation speed of the first fan unit (241), the method further comprises the following steps: Controlling the rotation speed of the first fan unit (241) to a minimum rotation speed; obtaining the high pressure pressure again, and comparing the high pressure pressure obtained for the second time with the system pressure; If the high pressure obtained for the second time is less than the system pressure, controlling the thermal management system of the energy storage unit to switch from the combined cooling mode to the natural cooling mode; In the natural cooling mode, the compressor (210) and the first fan unit (241) are turned off.

7. The control method of the thermal management system of the energy storage unit according to claim 5, characterized in that: Before gradually reducing the rotation speed of the second fan unit (242) to the minimum rotation speed, The following steps are involved: Preset cooling temperature; Obtaining the outlet water temperature of the refrigerant in the main circuit (100), and comparing the outlet water temperature with the refrigeration temperature; If the outlet water temperature is greater than the refrigeration temperature, the first fan unit (241) is controlled to operate at a preset speed, and the speed of the second fan unit (242) is gradually increased until the outlet water temperature is less than or equal to the refrigeration temperature.

8. The control method of the thermal management system of the energy storage unit according to claim 4, characterized in that: After comparing the ambient temperature with the first temperature and the second temperature, the following steps are also included: If the ambient temperature is less than or equal to the second temperature, controlling the thermal management system of the energy storage unit to enter the FC cooling mode; In the FC cooling mode, the compressor (210) is turned off, and the rotation speeds of the second fan unit (242) and the first fan unit (241) are controlled to decrease sequentially.

9. The control method of the energy storage unit thermal management system according to claim 8, characterized in that: The controlling the rotation speeds of the second fan group (242) and the first fan group (241) to decrease sequentially specifically comprises the following steps: gradually reducing the rotation speed of the second fan unit (242) to a minimum rotation speed, and controlling the second fan unit (242) to operate at the minimum rotation speed; The rotation speed of the first fan unit (241) is gradually reduced to a minimum rotation speed, and the first fan unit (241) is controlled to operate at the minimum rotation speed.

10. The control method of the thermal management system of the energy storage unit according to claim 4, characterized in that: After comparing the ambient temperature with the first temperature and the second temperature, the following steps are also included: If the ambient temperature is greater than or equal to the first temperature, controlling the thermal management system of the energy storage unit to enter an AC cooling mode; In the AC cooling mode, the first fan group (241) and the second fan group (242) are controlled to run at the same speed.

Images