Control method of energy storage equipment liquid cooling unit and liquid cooling unit system

Abstract

The invention discloses a control method of an energy storage equipment liquid cooling unit and a liquid cooling unit system. The energy storage equipment liquid cooling unit comprises a compressor, a condenser, an evaporator, an electronic expansion valve and a plurality of draught fans associated with the condenser. The control method comprises the steps that the environment temperature, the high-pressure side pressure and the high-pressure side saturation temperature during operation of the liquid cooling unit are obtained; when the high-pressure side pressure is larger than a preset starting pressure threshold value, at least one draught fan is started; when the pressure of the high-pressure side is smaller than a preset stop pressure threshold value, all the fans are stopped; and when at least one fan runs, according to the current high-pressure side saturation temperature, the number of the running fans is increased or decreased, at least one fan is kept running, and the upper limit of the number of the running fans is limited according to the current environment temperature. The invention provides the energy storage liquid cooling unit control method and system which are more accurate and can adapt to a wide environment temperature range, and the reliability, the stability and the operation economy of heat management of an energy storage system can be improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration technology, and in particular to a control method and system for a liquid-cooled unit in an energy storage device. Background Technology

[0002] With the rapid development of electrochemical energy storage technology, liquid-cooled units have become the mainstream thermal management solution for large-scale battery energy storage systems due to their high heat dissipation efficiency and good temperature uniformity. Liquid-cooled units continuously remove the heat generated by the battery through a refrigeration cycle, ensuring that the battery operates within a safe and efficient temperature range. The heat dissipation efficiency of the condenser directly affects the overall energy efficiency and reliability of the unit, and is typically achieved through forced air cooling using multiple fans.

[0003] In existing control strategies for energy storage liquid-cooled units, the start-up, shutdown, and speed regulation of the fans are mostly based on simple temperature or pressure thresholds. A common method is to detect the temperature at the condenser outlet or compressor exhaust port. When the temperature exceeds a certain set threshold, the fan is started or its speed is increased; when the temperature falls below another threshold, the speed is reduced or the fan is shut down. However, the above-mentioned existing control methods have shortcomings. On the one hand, the control is lagging and imprecise. The temperature at the compressor exhaust port is affected by various transient factors, such as sudden changes in compressor operating status and environmental wind speed disturbances, resulting in large signal fluctuations. Directly using this as the control basis can easily lead to frequent fan start-ups and shutdowns or speed oscillations, affecting not only system stability but also reducing energy efficiency. At the same time, although the pressure signal is relatively stable, relying solely on pressure control fails to directly correlate with the thermodynamic state, which better reflects the essence of heat transfer phase change, resulting in limited control accuracy. On the other hand, energy storage power stations operate in a wide range of ambient temperatures. In low-temperature environments, if the fan continues to operate at full speed according to the logic designed for high-temperature conditions, it will not only lead to excessively low condensing pressure, affecting the normal operation of components such as electronic expansion valves and causing system instability, but also waste the fan's power and reduce the overall energy efficiency ratio of the system.

[0004] Therefore, it is necessary to propose a technical solution to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, this invention proposes a more accurate control method and system for energy storage liquid-cooled units that can adapt to a wide range of ambient temperatures, which can improve the reliability, stability and economic efficiency of thermal management of energy storage systems.

[0006] This invention is achieved through the following technical solution: a control method for a liquid-cooled unit of an energy storage device, wherein the liquid-cooled unit of the energy storage device includes a compressor, a condenser, an evaporator, an electronic expansion valve, and multiple fans associated with the condenser, and the control method includes: The ambient temperature, high-pressure side pressure, and high-pressure side saturation temperature of the liquid chiller unit during operation are obtained. When the high-pressure side pressure is greater than the preset start-up pressure threshold, at least one fan is started; when the high-pressure side pressure is less than the preset stop-down pressure threshold, all fans are stopped. When at least one fan is running, the number of operating fans may be increased or decreased based on the current high-pressure side saturation temperature, with a minimum of one fan in operation. Additionally, the upper limit of the number of operating fans may be limited based on the current ambient temperature.

[0007] As a further improved technical solution, the number of fans is six or more, wherein the upper limit of the number of operating fans is limited according to the current ambient temperature, including: When Tenv-cur < Tenv1, the number of operating fans is 1; When Tenv1≤Tenv-cur<Tenv2, the maximum number of operating wind turbines is 2; When Tenv2≤Tenv-cur<Tenv3, the maximum number of operating wind turbines is 3; When Tenv3≤Tenv-cur<Tenv4, the maximum number of operating wind turbines is 4; When Tenv4≤Tenv-cur, the maximum number of operating wind turbines is 6; Where Tenv-cur is the current ambient temperature, and Tenv1 to Tenv4 are the preset first to fourth ambient temperature thresholds.

[0008] As a further improved technical solution, the preset first ambient temperature threshold Tenv1 has a value range of -15℃ to -5℃, the preset second ambient temperature threshold Tenv2 has a value range of 0℃ to 10℃, the preset third ambient temperature threshold Tenv3 has a value range of 10℃ to 20℃, and the preset fourth ambient temperature threshold Tenv4 has a value range of 15℃ to 25℃.

[0009] As a further improved technical solution, the number of operating fans can be increased or decreased based on the current high-pressure side saturation temperature, including: When T1≤Ts<T2, gradually reduce the number of operating fans; When T2≤Ts<T3, the number of currently operating fans remains unchanged; When T3≤Ts<T4, increase the number of operating fans one by one; Where Ts is the current high-pressure side saturation temperature, and T1 to T4 are the preset first to fourth temperature thresholds.

[0010] As a further improved technical solution, the value range of the preset first temperature threshold T1 is 20°C to 30°C, the value range of the preset second temperature threshold T2 is 30°C to 40°C, the value range of the preset third temperature threshold T3 is 35°C to 45°C, and the value range of the preset fourth temperature threshold T4 is 40°C to 50°C.

[0011] As a further improved technical solution, according to the magnitude of the current high-pressure side saturation temperature, increase or decrease the number of operating fans, including: When Ts < T1, keep the number of operating fans at 1; When T3 ≤ Ts < T4, the upper limit of the number of operating fans is less than the maximum number of fans.

[0012] As a further improved technical solution, the energy storage device liquid cooling unit includes six fans arranged in two rows and three columns, where: When one fan is operating, one of the two fans in the second column is operating; When two fans are operating, one fan is taken from each of the first column and the third column for operation; When three fans are operating, one fan is taken from each of the first, second, and third columns for operation; When four fans are operating, two in the second column and one taken from each of the first and third columns are operating; When five fans are operating, one taken from the second column and two from each of the first and third columns are operating.

[0013] As a further improved technical solution, among the six fans, one of the two fans in the second column is controlled to start and stop by the first switch, and the other and one fan taken from each of the first and third columns are controlled to start and stop synchronously by the second switch, and the other one fan in each of the first and third columns is controlled to start and stop synchronously by the third switch.

[0014] As a further improved technical solution, the control method further includes controlling the initial opening degree of the electronic expansion valve according to the current ambient temperature, specifically including: If Tenv-cur ≤ 0°C, the initial opening degree is set to the first opening value; If 0°C < Tenv-cur ≤ 35°C, the initial opening degree is set to the second opening value; If 35°C < Tenv-cur ≤ 45°C, the initial opening degree is set to the third opening value; If Tenv-cur > 45°C, the initial opening degree is set to the fourth opening value; Among them, Tenv-cur is the current ambient temperature, the first opening value > the second opening value = the fourth opening value > the third opening value.

[0015] This invention is also achieved through the following technical solution: a liquid-cooled unit system, comprising: The refrigerant circulation loop includes a compressor, condenser, electronic expansion valve, evaporator, and temperature and pressure sensors; Multiple fans are used to dissipate heat from the condenser; The controller is electrically connected to the pressure sensor, temperature sensor, electronic expansion valve, and the plurality of fans; The controller is configured to execute the control method described above.

[0016] The control method for liquid-cooled units in energy storage equipment provided by this invention effectively overcomes the shortcomings of existing technologies by using the high-pressure side saturation temperature as the core basis for adjusting the number of fans and introducing an upper limit constraint mechanism for the number of fans based on ambient temperature. This method utilizes the stable and direct thermodynamic parameter of saturation temperature, determined by system pressure, to characterize the condensing load, significantly improving the real-time performance and accuracy of control. It avoids frequent fan start-stops or oscillations caused by fluctuations in actual temperature signals, thereby improving the stability and reliability of system operation. Simultaneously, by intelligently limiting the maximum heat dissipation capacity based on ambient temperature, it ensures efficient and stable operation of the unit under a wide range of low-temperature environmental conditions, preventing excessively low condensing pressure and energy waste. Ultimately, it achieves energy efficiency optimization and reliable assurance of the energy storage liquid-cooled unit under all operating conditions. Attached Figure Description

[0017] Figure 1 This is a system connection diagram of an embodiment of the liquid cooling unit system of the present invention.

[0018] The attached diagram is labeled as follows: 1. Compressor; 2. Condenser; 3. Fan; 4. Electronic expansion valve; 5. Evaporator; 6. Water pump. Detailed Implementation

[0019] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Please see Figure 1This diagram illustrates the structure of a liquid-cooled unit system according to an embodiment of the present invention. The system mainly includes a refrigerant circulation loop, a coolant circulation loop, and a control system. The refrigerant circulation loop, in sequence according to the refrigerant flow direction, includes a compressor 1, a condenser 2, an electronic expansion valve 4, and an evaporator 5, which are connected by pipelines to form a closed loop. The compressor 1 compresses the gaseous refrigerant, increasing its pressure and temperature. The high-temperature, high-pressure gaseous refrigerant enters the condenser 2, where it condenses into a high-pressure liquid through heat exchange with external air. The heat released in this process is carried away by forced ventilation from one or more fans 3 located on the condenser 2 side. After the high-pressure liquid refrigerant is throttled and depressurized by the electronic expansion valve 4, it becomes a low-temperature, low-pressure gas-liquid two-phase fluid, which then enters the evaporator 5 to absorb heat and evaporate, thereby cooling the coolant flowing through the evaporator 5. Finally, the low-temperature, low-pressure gaseous refrigerant returns to the compressor 1, completing one cycle. The coolant circulation loop is cooled by the evaporator 5, which includes a water pump 6 and an energy storage device (not shown in the diagram) to be cooled, such as a battery pack. The evaporator 5 can specifically be a plate heat exchanger. Driven by water pump 6, the coolant flows through evaporator 5, is cooled by the refrigerant, and is then transported to the energy storage device to absorb the heat it generates. The heated coolant then circulates back through evaporator 5 for further cooling, thus providing precise temperature management for the energy storage device. The control system includes an ambient temperature sensor for detecting ambient temperature, a pressure sensor for detecting the high-pressure side pressure, a temperature sensor for detecting the high-pressure side temperature, and a controller. The controller is electrically connected to compressor 1, electronic expansion valve 4, fan 3, water pump 6, and each sensor, receiving sensor signals and outputting control commands according to preset control logic to coordinate the operation of the entire system.

[0022] Based on the above system, the present invention provides a control method for a liquid-cooled unit of an energy storage device. The control method includes: acquiring the ambient temperature, high-pressure side pressure, and high-pressure side saturation temperature during the operation of the liquid-cooled unit; starting at least one fan 3 when the high-pressure side pressure is greater than a preset start-up pressure threshold; stopping all fans 3 when the high-pressure side pressure is less than a preset stop-down pressure threshold; increasing or decreasing the number of operating fans 3 according to the current high-pressure side saturation temperature, while maintaining at least one fan 3 in operation; and limiting the upper limit of the number of operating fans 3 according to the current ambient temperature.

[0023] The core of this invention lies in the intelligent collaborative control method for the condenser fan 3 executed by the controller. This method abandons the traditional approach of directly using fluctuating actual exhaust temperature or a single pressure threshold for control. Instead, it uses the high-pressure side saturation temperature as the core basis for adjusting the number of fans and introduces an upper limit constraint mechanism for the number of fans based on ambient temperature, effectively overcoming the shortcomings of existing technologies. This method utilizes the stable and direct thermodynamic parameter of saturation temperature, determined by system pressure, to characterize the condensing load, significantly improving the real-time performance and accuracy of control. It avoids frequent fan start-stops or oscillations caused by fluctuations in actual temperature signals, thereby improving the stability and reliability of system operation. Simultaneously, by intelligently limiting the maximum heat dissipation capacity based on ambient temperature, it ensures the unit's efficient and stable operation under a wide range of low-temperature environmental conditions, preventing excessively low condensing pressure and energy waste, ultimately achieving energy efficiency optimization and reliable assurance for the energy storage liquid cooling unit under all operating conditions.

[0024] Specifically, the first step is to acquire the key parameters required for control. The controller collects the current ambient temperature (Tenv-cur), high-pressure side pressure, and high-pressure side saturation temperature (Ts) in real time during the operation of the liquid chiller. It is important to note that the high-pressure side saturation temperature (Ts) is not a physical temperature directly measured by a temperature sensor, but a calculated key parameter reflecting the system's thermodynamic state. In practice, the controller acquires the real-time high-pressure side pressure through a pressure sensor. Then, based on the type of refrigerant used in the system (e.g., R410A, R134a), it consults a pressure-saturation temperature property lookup table pre-stored in the controller's memory or uses a built-in calculation formula to obtain the unique saturation temperature value (Ts) corresponding to the current pressure. This parameter directly characterizes the condensation state of the refrigerant in the condenser, eliminating interference from superheat fluctuations that may be present in the actual exhaust temperature. Therefore, it is more stable and accurate than directly measured values, laying a reliable data foundation for subsequent precise control.

[0025] Secondly, basic start-stop control of the fan group is implemented based on high-pressure side pressure. When the high-pressure side pressure is greater than a preset start-up pressure threshold, at least one fan is started; when the high-pressure side pressure is less than a preset stop-down pressure threshold, all fans are stopped. Specifically, the controller compares the real-time high-pressure side pressure with preset start-up and stop-down pressure thresholds. When the high-pressure side pressure is greater than the start-up pressure threshold, it indicates that the system condensation load has increased, requiring the cooling fans to be started. At this time, the controller issues a command to start at least one fan 3, for example, by default, one fan is started to begin basic cooling. When the high-pressure side pressure is less than the stop-down pressure threshold, it indicates that the system condensation load is very low, and all fans 3 can be stopped to save energy. This pressure start-stop logic constitutes the basic threshold for the operation of fans 3, ensuring that fans 3 only operate when necessary, avoiding ineffective operation under low load. In one embodiment, the start-up pressure threshold is, for example, 2500 kPa, and the stop-down pressure threshold is, for example, 1100 kPa.

[0026] With at least one wind turbine 3 already in operation, the controller begins executing dynamic adjustment and constraint control logic. This stage comprises two parallel and interconnected logics: first, dynamically increasing or decreasing the number of operating wind turbines 3 based on the high-pressure side saturation temperature Ts; and second, imposing a rigid upper limit constraint on the maximum number of wind turbines 3 allowed to be put into operation based on the current ambient temperature Tenv-cur. These two logics work together to ensure the accuracy of adjustment and the safety and economy of operation.

[0027] Regarding the dynamic adjustment of the number of operating fans 3 based on the high-pressure side saturation temperature Ts, the controller compares the real-time calculated high-pressure side saturation temperature Ts with multiple preset temperature thresholds to determine whether to increase, decrease, or maintain the number of currently operating fans 3. As a preferred refined control strategy, four temperature thresholds T1, T2, T3, and T4 can be set, where T1 < T2 < T3 < T4, and the following rules apply: When Ts is lower than T1, it indicates that the condensing load is extremely low, and the controller keeps the number of operating fans 3 at the minimum of 1 to maintain only the most basic heat dissipation; when Ts is in the range [T1, T2), it indicates that the condensing load is decreasing, and the controller gradually reduces the number of operating fans 3, but ensures that at least 1 is kept running; when Ts is in the range [T2, T3), it indicates that the condensing load is basically matched with the current heat dissipation capacity, and the controller keeps the number of operating fans 3 unchanged to maintain system stability; when Ts is in the range [T3, T4), it indicates that the condensing load is increasing, and the controller gradually increases the number of operating fans 3 to enhance heat dissipation capacity; when Ts reaches or exceeds T4, it indicates that the condensing load is very high, and the controller controls the number of operating fans to reach the upper limit allowed by the current ambient temperature, which is not necessarily all fans 3, but is also subject to the ambient temperature constraint mentioned below. The aforementioned thresholds can be optimized based on different refrigerants and system designs. For example, the value of T1 can be between 20℃ and 30℃, such as 25℃; the value of T2 can be between 30℃ and 40℃, such as 35℃; the value of T3 can be between 35℃ and 45℃, such as 40℃; and the value of T4 can be between 40℃ and 50℃, such as 46℃. This gradual adjustment method based on the saturation temperature range allows for a smooth response to changes in system load, effectively avoiding frequent and drastic fluctuations in the number of fans caused by signal fluctuations or threshold crossings, greatly improving the stability and control accuracy of system operation. For specific types of refrigerants, the high-pressure side pressure is 1550 kPa at a saturation temperature of 25℃, 2030 kPa at 35℃, 2317 kPa at 40℃, and 2690 kPa at 46℃.

[0028] Regarding the rigid upper limit constraint based on the ambient temperature Tenv-cur, this is a key design for the present invention to adapt to a wide operating environment and ensure stable operation under low-temperature conditions. The controller delimits the upper limit of the number of fans 3 allowed to be put into operation according to the real-time ambient temperature Tenv-cur. In this embodiment, four ambient temperature thresholds Tenv1, Tenv2, Tenv3, and Tenv4 can be set, where Tenv1 < Tenv2 < Tenv3 < Tenv4, and the number of fans 3 is six or more. Among them, restricting the upper limit of the number of operating fans 3 according to the current ambient temperature Tenv-cur includes: when Tenv-cur < Tenv1, regardless of how high the high-pressure side saturation temperature is, the upper limit of the number of operating fans 3 is compulsorily set to 1; when Tenv1 ≤ Tenv-cur < Tenv2, the upper limit of the number of operating fans is 2; when Tenv2 ≤ Tenv-cur < Tenv3, the upper limit of the number of operating fans is 3; when Tenv3 ≤ Tenv-cur < Tenv4, the upper limit of the number of operating fans is 4; when Tenv-cur ≥ Tenv4, the upper limit of the number of operating fans is allowed to reach the maximum number of fans in the system, such as 6. These ambient temperature thresholds can be set according to typical climate conditions and unit characteristics. For example, the value range of Tenv1 can be -15°C to -5°C, such as -10°C; the value range of Tenv2 can be 0°C to 10°C, such as 5°C; the value range of Tenv3 can be 10°C to 20°C, such as 15°C; the value range of Tenv4 can be 15°C to 25°C, such as 20°C. The core function of this constraint mechanism is that in a low-temperature environment, it actively restricts the maximum heat dissipation capacity of the fans to prevent the condensation pressure from being too low due to excessive heat dissipation. Too low condensation pressure will reduce the pressure difference before and after the electronic expansion valve 4, affecting its normal regulation function. In severe cases, it may lead to problems such as poor refrigerant circulation in the system and insufficient liquid supply to the evaporator 5, affecting the refrigeration effect and system reliability. At the same time, restricting the number of fans also directly reduces the unnecessary fan power consumption in a low-temperature environment, improving the overall energy efficiency ratio of the system.

[0029] The dynamic adjustment of the number of operating fans 3 and the upper limit constraint on the number of operating fans 3 are calculated synchronously in real time. The final decision logic of the controller is as follows: First, calculate the required number of fans based on the current Ts; then, determine the maximum allowed number of fans based on the current Tenv-cur; finally, compare the required number of fans with the maximum allowed number of fans, and take the smaller value as the target number of fans for the final command output. For example, assuming that the current Ts is very high, and the adjustment logic requires 5 fans, but the current Tenv-cur is in the range [Tenv2, Tenv3), with an allowed upper limit of 3 fans, then the controller will ultimately only operate 3 fans. This ensures that, under any ambient temperature, the system's heat dissipation capacity is controlled within a reasonable range that meets basic condensation requirements without causing low-pressure problems due to excessive heat dissipation.

[0030] To further optimize heat dissipation uniformity, reduce the impact of starting and stopping a single fan 3 on local heat exchange in the condenser 2, and simplify the control circuit, this invention also proposes preferred solutions for the specific arrangement and electrical connection of multiple fans 3. In one embodiment, the system is configured with six fans 3, arranged in two rows and three columns on the back of the condenser 2. More specifically, the first column, the second column, and the third column are defined, each column containing two fans 3 arranged vertically. The starting and stopping of these six fans 3 are not completely independently controlled, but are grouped and controlled by three switches K1, K2, and K3 to achieve six operating levels corresponding to 1 to 6 fans. The switches are, for example, AC contactors. The connection is as follows: the power supply line of one fan in the second column (e.g., the upper fan) is controlled by the first switch K1; the power supply lines of another fan in the second column (e.g., the lower fan) are connected in parallel with the power supply lines of one designated fan in each of the first and third columns (e.g., both are upper fans or both are lower fans), and are controlled to start and stop synchronously by the second switch K2; the remaining two fans in the first and third columns, i.e., the fans in the same column but different row as the K2 control group, have their power supply lines connected in parallel, and are controlled to start and stop synchronously by the third switch K3. By arranging the closing combinations of the three switches K1, K2, and K3, the aforementioned six operating levels can be precisely achieved. That is, closing only K1 will operate one fan in the second column; closing only K3 will operate two fans, one from the first and one from the third column; closing only K2 will operate three fans, one from the second column and one from the first and one from the third column; closing K1 and K2 and opening K3 will operate four fans; closing K2 and K3 and opening K1 will operate five fans simultaneously; and closing all three (K1, K2, and K3) will operate all six fans. This arrangement and control method ensures that, with any number of fans increasing from one to six, the operating fans are essentially symmetrically distributed on the condenser 2. This not only guarantees that the airflow can relatively evenly cover different areas of the condenser 2 with different numbers of fans, avoiding local overheating or overcooling, but also achieves six levels of fine control with only three control switches, simplifying the hardware circuit and reducing costs and failure rates.

[0031] In addition, to make the control of the entire system more collaborative and efficient, the control method of the embodiment of the present invention further includes optimizing the setting of the initial opening degree of the electronic expansion valve 4 based on the ambient temperature. When the unit starts up or the mode is switched to refrigeration operation, the electronic expansion valve 4 requires an initial opening degree. The controller sets this initial opening degree according to the current ambient temperature Tenv-cur: if Tenv-cur ≤ 0°C, the initial opening degree is set to a relatively large first opening degree value (for example, the maximum opening degree of 480 steps); if 0°C < Tenv-cur ≤ 35°C, the initial opening degree is set to a moderate second opening degree value (for example, 400 steps); if 35°C < Tenv-cur ≤ 45°C, the initial opening degree is set to a relatively small third opening degree value (for example, 300 steps); if Tenv-cur > 45°C, the initial opening degree is set again to a fourth opening degree value equal to the second opening degree value (for example, 400 steps). This setting logic takes into account the characteristics of the system pressure ratio and refrigerant flow rate at different ambient temperatures: at low temperatures, increasing the initial opening degree is beneficial for the system to quickly establish a pressure difference and circulation; a moderate opening degree is adopted in the normal temperature range; at relatively high ambient temperatures (35 - 45°C), appropriately reducing the initial opening degree helps to prevent the compressor from overloading in the initial stage of startup; at extremely high ambient temperatures, the moderate opening degree is restored to provide sufficient refrigerant flow rate. This provides a good starting point for the system to quickly and smoothly enter the stable operation state and complements the intelligent control of the fan.

[0032] In summary, the control method and system for the energy storage device liquid cooling unit provided by the embodiment of the present invention form a complete and intelligent thermal management solution by dynamically and precisely adjusting the number of fans using the stable parameter of the high-pressure side saturation temperature, innovatively introducing the adaptive limitation of the ambient temperature on the maximum operating number of fans, supplemented by an optimized fan layout and control circuit connection method, and the initial opening degree strategy of the electronic expansion valve. This method effectively overcomes the defects of the traditional control method such as lag, oscillation, and poor low-temperature adaptability, significantly improves the operation stability, reliability, and energy efficiency level of the energy storage liquid cooling unit under different environmental conditions, and has good practical value and promotion prospects.

[0033] The present invention is illustrated by several specific embodiments. Those skilled in the art should understand that various transformations and equivalent substitutions can be made to the present invention without departing from the scope of the present invention. In addition, various modifications can be made to the present invention for a specific situation or circumstance without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims of the present invention.

Claims

1. A control method for a liquid-cooled unit of an energy storage device, the liquid-cooled unit comprising a compressor, a condenser, an evaporator, an electronic expansion valve, and multiple fans associated with the condenser, characterized in that, The control method includes: The ambient temperature, high-pressure side pressure, and high-pressure side saturation temperature of the liquid chiller unit during operation are obtained. When the high-pressure side pressure is greater than the preset start-up pressure threshold, at least one fan is started; when the high-pressure side pressure is less than the preset stop-down pressure threshold, all fans are stopped. When at least one fan is running, the number of operating fans may be increased or decreased based on the current high-pressure side saturation temperature, with a minimum of one fan in operation. Additionally, the upper limit of the number of operating fans may be limited based on the current ambient temperature.

2. The control method according to claim 1, characterized in that, The number of fans is six or more, wherein the upper limit of the number of operating fans is limited by the current ambient temperature, including: When Tenv-cur < Tenv1, the number of operating fans is 1; When Tenv1≤Tenv-cur<Tenv2, the maximum number of operating wind turbines is 2; When Tenv2≤Tenv-cur<Tenv3, the maximum number of operating wind turbines is 3; When Tenv3≤Tenv-cur<Tenv4, the maximum number of operating wind turbines is 4; When Tenv4≤Tenv-cur, the maximum number of operating wind turbines is 6; Where Tenv-cur is the current ambient temperature, and Tenv1 to Tenv4 are the preset first to fourth ambient temperature thresholds.

3. The control method according to claim 2, characterized in that, The preset first ambient temperature threshold Tenv1 has a value range of -15℃ to -5℃, the preset second ambient temperature threshold Tenv2 has a value range of 0℃ to 10℃, the preset third ambient temperature threshold Tenv3 has a value range of 10℃ to 20℃, and the preset fourth ambient temperature threshold Tenv4 has a value range of 15℃ to 25℃.

4. The control method according to claim 1 or 2, characterized in that, Based on the current high-pressure side saturation temperature, the number of operating fans may be increased or decreased, including: When T1≤Ts<T2, gradually reduce the number of operating fans; When T2≤Ts<T3, the number of currently operating fans remains unchanged; When T3≤Ts<T4, increase the number of operating fans one by one; Where Ts is the current high-pressure side saturation temperature, and T1 to T4 are the preset first to fourth temperature thresholds.

5. The control method according to claim 4, characterized in that, The preset first temperature threshold T1 has a value range of 20℃~30℃, the preset second temperature threshold T2 has a value range of 30℃~40℃, the preset third temperature threshold T3 has a value range of 35℃~45℃, and the preset fourth temperature threshold T4 has a value range of 40℃~50℃.

6. The control method according to claim 4, characterized in that, Based on the current high-pressure side saturation temperature, the number of operating fans may be increased or decreased, including: When Ts < T1, the number of operating fans remains at 1; When T3≤Ts<T4, the upper limit of the number of operating fans is less than the maximum number of fans.

7. The control method according to claim 4, characterized in that, The energy storage equipment liquid cooling unit includes six fans arranged in two rows and three columns, wherein: When one fan is running, it is operated by one of the two fans in the second column; When two fans are running, one fan is selected from the first column and one from the third column to operate. When all three fans are running, one fan from each of the first, second, and third columns is selected to operate. When all four fans are running, two fans from the second column and one fan from each of the first and third columns will be in operation. When five fans are running, one taken from the second column and two fans from each of the first and third columns are running.

8. The control method according to claim 7, characterized in that, Among the six fans, one of the two fans in the second column is controlled to start and stop by the first switch, and the other one taken from each of the first and third columns and the other fan are controlled to start and stop synchronously by the second switch, and the other one of each of the first and third columns is controlled to start and stop synchronously by the third switch.

9. The control method according to claim 1, characterized in that, The control method further includes controlling the initial opening degree of the electronic expansion valve according to the current ambient temperature, specifically including: If Tenv-cur ≤ 0°C, the initial opening degree is set to the first opening value; If 0°C < Tenv-cur ≤ 35°C, the initial opening degree is set to the second opening value; If 35°C < Tenv-cur ≤ 45°C, the initial opening degree is set to the third opening value; If Tenv-cur > 45°C, the initial opening degree is set to the fourth opening value; Wherein, Tenv-cur is the current ambient temperature, the first opening value > the second opening value = the fourth opening value > the third opening value.

10. A liquid-cooled unit system, characterized in that, The liquid-cooled unit system includes: A refrigerant circulation circuit, including a compressor, a condenser, an electronic expansion valve, an evaporator, and temperature sensors and pressure sensors; Multiple fans for dissipating heat from the condenser; A controller electrically connected to the pressure sensor, the temperature sensor, the electronic expansion valve, and the multiple fans; Wherein, the controller is configured to execute the control method according to any one of claims 1 to 9.

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