Direct cooling system and refrigerant dryness control method, device and storage medium thereof

Abstract

This invention discloses a direct cooling system and its refrigerant dryness control method, device, and storage medium. The direct cooling system includes a regenerator, a main valve, a regenerative heat control valve, and an indoor unit module. The number of cold plate branches in the indoor unit module corresponds to the number of battery cell modules. Each cold plate branch includes a branch cold plate and a branch control valve. The method includes: obtaining the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and obtaining the refrigerant specific enthalpy at the evaporation side outlet of each cold plate branch; further, obtaining the actual refrigerant dryness of each cold plate branch; and, when the current operating condition is refrigeration, the refrigerant at the regenerator inlet side is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled separately to adjust the refrigerant flow rate of each cold plate branch. This simplifies the refrigerant dryness control parameters, achieves refrigerant dryness control of the direct cooling system, and thus achieves temperature uniformity control of the battery cell modules.

Description

Technical Field

[0001] This invention relates to the field of direct cooling system control technology, and in particular to a method for controlling the refrigerant dryness of a direct cooling system, a computer-readable storage medium, a device for controlling the refrigerant dryness of a direct cooling system, and a direct cooling system. Background Technology

[0002] With the development of energy storage and battery fields, the heat flux density of battery cells is gradually increasing. Air cooling can no longer meet the heat dissipation requirements of current energy storage batteries. At present, the mainstream heat dissipation method for batteries is non-contact liquid cooling. However, this method requires a large amount of circulating water to ensure battery temperature uniformity, consuming a lot of pumping power. To address this, related technologies have replaced liquid cooling with direct refrigerant cooling to improve the system's energy utilization efficiency. However, the problem with this technology is that the refrigerant dryness in direct refrigerant cooling often requires a large number of known parameters for derivation, making the control process complex and hindering product commercialization. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to propose a method for controlling the refrigerant dryness of a direct-cooling system, which simplifies the refrigerant dryness control parameters, enables control of the refrigerant dryness of the direct-cooling system, and thereby achieves temperature uniformity control of the battery cell assembly.

[0004] A second objective of this invention is to provide a computer-readable storage medium.

[0005] The third objective of this invention is to provide a refrigerant dryness control device for a direct cooling system.

[0006] The fourth objective of this invention is to provide a direct cooling system.

[0007] To achieve the above objectives, a first aspect of the present invention proposes a method for controlling the refrigerant dryness of a direct cooling system. The direct cooling system includes a regenerator, a main valve and a regenerative heat control valve corresponding to the regenerator, and an indoor unit module. The number of cold plate branches in the indoor unit module corresponds to the number of battery cell modules. Each cold plate branch includes a branch cold plate and a branch control valve. The method includes: acquiring the current operating condition of the direct cooling system; acquiring the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure and the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and... Obtain the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch; based on the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure, the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch, obtain the actual refrigerant dryness of each cold plate branch; when the current operating condition is refrigeration condition, the refrigerant at the inlet of the regenerator is subcooled, and based on the actual refrigerant dryness of each cold plate branch, control the branch control valve of each cold plate branch to adjust the refrigerant flow rate of each cold plate branch.

[0008] According to the refrigerant dryness control method for a direct cooling system proposed in this embodiment, the current operating condition of the direct cooling system is obtained. Then, the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at the saturated evaporation pressure are obtained, and the refrigerant specific enthalpy at the evaporator outlet of each cold plate branch is also obtained. Then, based on the gaseous specific enthalpy, liquid specific enthalpy, and evaporator outlet of each cold plate branch, the actual refrigerant dryness of each cold plate branch is obtained. Furthermore, when the current operating condition is refrigeration, the refrigerant at the inlet of the regenerator is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled to adjust the refrigerant flow rate of each cold plate branch. This simplifies the refrigerant dryness control parameters, enabling refrigerant dryness control of the direct cooling system, thereby achieving temperature uniformity control of the battery cell assembly.

[0009] In addition, the refrigerant dryness control method for the direct cooling system according to the above embodiments of the present invention may also have the following additional technical features:

[0010] According to one embodiment of the present invention, obtaining the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch includes: obtaining the refrigerant specific enthalpy at the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy at the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system; obtaining the total cooling capacity of the indoor unit module based on the refrigerant specific enthalpy at the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy at the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system; obtaining the heat exchange capacity ratio of each cold plate branch; obtaining the branch cold plate heat exchange capacity corresponding to each cold plate branch based on the total cooling capacity and the heat exchange capacity ratio of each cold plate branch; and obtaining the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch based on the branch cold plate heat exchange capacity corresponding to each cold plate branch.

[0011] According to an embodiment of the present invention, the actual refrigerant dryness of the cold plate branch is obtained by the following formula: x = (h i-out -h eva-l ) / (h eva-v -h eva-l ), where x is the actual refrigerant dryness of the i-th cold plate branch, h i-out h is the specific enthalpy of the refrigerant at the evaporator outlet of the i-th cold plate branch. eva-v h is the specific enthalpy of the refrigerant in gaseous state at saturated evaporation pressure. eva-l It is the specific enthalpy of the refrigerant in liquid state at saturated evaporation pressure.

[0012] According to one embodiment of the present invention, controlling the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch includes: if the actual refrigerant dryness of the current cold plate branch is greater than the target preset refrigerant dryness, then increasing the valve opening of the branch control valve corresponding to the current cold plate branch; if the actual refrigerant dryness of the current cold plate branch is less than the target preset refrigerant dryness, then decreasing the valve opening of the branch control valve corresponding to the current cold plate branch.

[0013] According to one embodiment of the present invention, before controlling the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch, the method further includes: obtaining the return superheat, exhaust superheat and subcooling of the refrigerant; and controlling the main valve and the regenerative heat control valve according to the return superheat, exhaust superheat and subcooling of the refrigerant.

[0014] According to one embodiment of the present invention, the method further includes: when the current operating condition is a heating condition, acquiring the heat exchange capacity of the regenerator; and controlling the heat exchange capacity control valve based on the heat exchange capacity of the regenerator.

[0015] According to one embodiment of the present invention, the method further includes: obtaining the average cell temperature of the cell assembly; and performing frequency modulation control on the compressor based on the average cell temperature of the cell assembly.

[0016] To achieve the above objectives, a computer-readable storage medium is provided in the second aspect of the present invention, which stores a refrigerant dryness control program for a direct cooling system. When the refrigerant dryness control program for the direct cooling system is executed by a processor, it implements the refrigerant dryness control method for the direct cooling system described in the embodiments of the present invention.

[0017] According to the computer-readable storage medium proposed in the embodiments of the present invention, by executing the refrigerant dryness control program of the direct cooling system stored thereon, the refrigerant dryness control parameters can be simplified, and the refrigerant dryness control of the direct cooling system can be realized, thereby realizing the temperature uniformity control of the battery cell assembly.

[0018] To achieve the above objectives, a third aspect of the present invention provides a refrigerant dryness control device for a direct cooling system. The direct cooling system includes a regenerator, a main valve and a regenerative heat control valve corresponding to the regenerator, and an indoor unit module. The number of cold plate branches in the indoor unit module corresponds to the number of battery cell modules. Each cold plate branch includes a branch cold plate and a branch control valve. The method includes: a first acquisition module for acquiring the current operating condition of the direct cooling system; and a second acquisition module for acquiring the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure and the liquid specific enthalpy of the refrigerant at saturated evaporation pressure. The system includes a first module for obtaining the refrigerant specific enthalpy at the evaporator outlet of each cold plate branch; a second module for obtaining the actual refrigerant dryness of each cold plate branch based on the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure, the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and the refrigerant specific enthalpy at the evaporator outlet of each cold plate branch; and a third module for obtaining the actual refrigerant dryness of each cold plate branch when the current operating condition is refrigeration condition and the refrigerant at the inlet of the regenerator is subcooled, thereby adjusting the refrigerant flow rate of each cold plate branch based on the actual refrigerant dryness of each cold plate branch.

[0019] The refrigerant dryness control device for a direct cooling system according to an embodiment of the present invention acquires the current operating condition of the direct cooling system through a first acquisition module. Then, a second acquisition module acquires the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at the saturated evaporation pressure, and acquires the refrigerant specific enthalpy at the evaporator outlet of each cold plate branch. Next, a third acquisition module acquires the actual refrigerant dryness of each cold plate branch based on the gaseous specific enthalpy, liquid specific enthalpy, and evaporator outlet specific enthalpy of the refrigerant at the saturated evaporation pressure. Furthermore, when the current operating condition is refrigeration, the refrigerant at the inlet of the regenerator is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the control module controls the branch control valve of each cold plate branch to adjust the refrigerant flow rate of each cold plate branch. This simplifies the refrigerant dryness control parameters, enabling refrigerant dryness control of the direct cooling system, thereby achieving temperature uniformity control of the battery cell assembly.

[0020] To achieve the above objectives, the direct cooling system proposed in the fourth aspect of the present invention includes the refrigerant dryness control device of the direct cooling system described in the above embodiments of the present invention.

[0021] According to the direct cooling system of the present invention, by adopting the aforementioned refrigerant dryness control device for the direct cooling system, the refrigerant dryness control parameters can be simplified, and the refrigerant dryness control of the direct cooling system can be realized, thereby realizing the temperature uniformity control of the battery cell assembly.

[0022] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a direct cooling system according to an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of an internal unit module according to an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the structure of an in-unit module according to another embodiment of the present invention;

[0026] Figure 4 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0027] Figure 5 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0028] Figure 6 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0029] Figure 7 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0030] Figure 8 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0031] Figure 9 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention;

[0032] Figure 10 This is a block diagram of a refrigerant dryness control device for a direct cooling system according to an embodiment of the present invention;

[0033] Figure 11 This is a block diagram of a direct cooling system according to an embodiment of the present invention.

[0034] Figure label:

[0035] The direct cooling system 1000 includes: compressor 1, four-way valve 2, finned heat exchanger 3, fan 4, regenerator 5, main valve 6, regenerator control valve 7, indoor unit module 8, gas-liquid separator 9, branch cold plate 801, branch control valve 802, refrigerant dryness control device 100 for the direct cooling system, first acquisition module 10, second acquisition module 20, third acquisition module 30, control module 40, temperature sensor T3, temperature sensor TL, temperature sensor Th, temperature sensors T2A1, T2A2, T2A3, T2A4, T2A5, T2A6, ..., T2An, temperature sensors T2B1, T2B2, T2B3, T2B4, T2B5, T2B6, ..., T2Bn, and each branch cold plate m1, m2, m3, m4, m5, m6, ..., mn. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] The following description, with reference to the accompanying drawings, describes a refrigerant dryness control method, a computer-readable storage medium, a refrigerant dryness control device, and a direct cooling system according to embodiments of the present invention.

[0038] First, the refrigerant circulation path of the direct cooling system in this embodiment of the invention will be described accordingly, such as... Figure 1 and Figure 2 As shown, the direct cooling system 1000 includes a compressor 1, a four-way valve 2, a finned heat exchanger 3, a fan 4, a regenerator 5, a main valve 6 and a regenerator control valve 7 corresponding to the regenerator 5, an indoor unit module 8, and a gas-liquid separator 9, wherein, as Figure 3 As shown, the number of cold plate branches in the indoor unit module 8 corresponds to the number of battery cell blocks. Each cold plate branch includes a branch cold plate 801 and a branch control valve 802.

[0039] Optionally, in some embodiments of the present invention, such as Figure 1 As shown, the main valve 6 can be installed at the outlet of the high-pressure end of the regenerator 5, and, as... Figure 2 As shown, the main valve 6 can also be installed at the inlet of the liquid pipe.

[0040] Specifically, such as Figure 1 and Figure 3As shown, taking the direct cooling system 1000 as an example for cell cooling, port a of the four-way valve 2 is connected to port b, and port c is connected to port d. The refrigerant is compressed by the compressor 1 and enters port a of the four-way valve 2. After exiting port b, it enters the finned heat exchanger 3. The finned heat exchanger 3 is connected to the fan 4. After exiting the finned heat exchanger 3, the refrigerant is split. One side bypasses the heat recovery control valve 7, and the other side enters the high-pressure chamber of the heat recovery valve 5. After passing through the main valve 6, the refrigerant on the side of the heat recovery control valve 7 is combined and enters the indoor unit module 8 through the liquid pipe. After entering the indoor unit module 8, the refrigerant is split. The split refrigerant enters the branch cold plate 801 through the corresponding branch control valve 802 to cool the cell. Then, the refrigerant is combined at the outlet of the indoor unit module 8 and enters the low-pressure chamber of the heat recovery valve 5 through the gas pipe. Then, it enters port d of the four-way valve and is discharged from port c to the gas-liquid separator 9. Then, it enters the compressor 1 through the gas-liquid separator 9 to form a refrigerant cycle.

[0041] Figure 4 This is a schematic flowchart of a refrigerant dryness control method for a direct cooling system according to an embodiment of the present invention.

[0042] Specifically, in some embodiments of the present invention, such as Figure 4 As shown, the refrigerant dryness control method for a direct cooling system includes:

[0043] S101, obtain the current operating condition of the direct cooling system.

[0044] It is understood that, in this embodiment of the present invention, the direct cooling system includes two operating modes during actual control: a cooling mode and a heating mode.

[0045] S102, obtain the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure and the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and obtain the specific enthalpy of the refrigerant at the evaporation side outlet of each cold plate branch.

[0046] It is understood that in this embodiment of the present invention, the saturated evaporation temperature of the refrigerant is obtained by setting a temperature sensor, and then the saturated evaporation temperature is converted into the corresponding saturated evaporation pressure. Then, the gaseous specific enthalpy of the refrigerant and the liquid specific enthalpy of the refrigerant at the saturated evaporation pressure are calculated based on the saturated evaporation pressure.

[0047] And, in this embodiment of the invention, as Figure 3As shown, the inlet and outlet temperatures of each branch cold plate (m1, m2, m3, m4, m5, m6, ..., mn) are obtained by using temperature sensors (T2A1, T2A2, T2A3, T2A4, T2A5, T2A6, ..., T2An) installed at the inlet of the branch cold plate 801 and temperature sensors (T2B1, T2B2, T2B3, T2B4, T2B5, T2B6, ..., T2Bn) installed at the outlet of the branch cold plate 801. Then, based on the inlet and outlet temperatures of each branch cold plate, the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch is calculated.

[0048] Specifically, in some embodiments of the present invention, such as Figure 5 As shown, the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch is obtained, including:

[0049] S201, obtain the refrigerant specific enthalpy on the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy on the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system.

[0050] It is understood that, in this embodiment of the present invention, the temperature at the low-pressure outlet of the regenerator is obtained by a temperature sensor located at the low-pressure outlet of the regenerator, the temperature at the high-pressure inlet of the regenerator is obtained by a temperature sensor located at the high-pressure inlet of the regenerator, and the temperature at the high-pressure outlet of the regenerator is obtained by a temperature sensor located at the high-pressure outlet of the regenerator. Furthermore, the refrigerant specific enthalpy h at the low-pressure inlet of the regenerator is obtained based on the temperatures at the low-pressure outlet, the high-pressure inlet, and the high-pressure outlet. lo The refrigerant specific enthalpy h at the high-pressure inlet side of the regenerator is obtained based on the temperature at the high-pressure outlet side of the regenerator. ho .

[0051] Furthermore, in this embodiment of the invention, the total refrigerant flow rate of the direct cooling system is calculated by detecting the intake saturation temperature and exhaust saturation temperature of the refrigerant.

[0052] S202: Based on the refrigerant specific enthalpy on the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy on the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system, the total cooling capacity of the indoor unit module is obtained.

[0053] It is understood that, in this embodiment of the present invention, the total cooling capacity of the indoor unit module can be obtained by the following formula:

[0054] Q c =X×(h) lo -h ho );

[0055] Among them, Q c X represents the total cooling capacity of the indoor unit module, and H represents the total refrigerant flow rate of the direct cooling system. loh is the refrigerant specific enthalpy on the low-pressure inlet side of the regenerator. ho This refers to the specific enthalpy of the refrigerant on the high-pressure inlet side.

[0056] S203, obtain the heat exchange capacity ratio of each cold plate branch, and obtain the branch cold plate heat exchange capacity corresponding to each cold plate branch based on the total cooling capacity and the heat exchange capacity ratio of each cold plate branch.

[0057] It should be understood that since the heat exchange capacity ratio of each cold plate branch is related to the refrigerant flow rate through each cold plate branch, in this embodiment of the present invention, the flow rate ratio of each cold plate branch is first estimated by an expansion valve model, and then the total refrigerant flow rate of the direct cooling system is estimated by a compressor coefficient model. Then, the actual flow rate of each cold plate branch is calculated by combining the flow rate ratio of each cold plate branch and the total refrigerant flow rate of the direct cooling system. Finally, the heat exchange capacity of the cold plate corresponding to each cold plate branch is obtained based on the actual flow rate of each cold plate branch.

[0058] Optionally, in some embodiments of the present invention, the expansion valve model is defined as follows:

[0059]

[0060] Where m is the mass flow rate of the refrigerant, P in P is the pressure before the refrigerant expansion valve. out ρ is the pressure after the refrigerant expansion valve. in ν is the density of the refrigerant before the expansion valve. out This refers to the specific volume after the refrigerant expansion valve.

[0061] The compressor ten-coefficient model is defined as follows:

[0062] X = C0 + C1·S + C2·D + C3·S 2 +C4S·D+C5D 2 +C6S 3 +C7S 2 ·D+C8S·D 2 +C9D 3 ;

[0063] Where C0 to C9 represent ten constant coefficients, and the fitting formula is obtained by least squares programming. D is the exhaust saturation temperature and S is the intake saturation temperature. Thus, by substituting different ten coefficients, the corresponding cooling capacity, power, flow rate and compressor current can be obtained.

[0064] Therefore, by combining the expansion valve model, the refrigerant flow rates of the n cold plate branches can be calculated sequentially as m1, m2, ..., mn. Simultaneously, by combining the compressor coefficient model, the total refrigerant flow rate X of the direct cooling system can be calculated. Thus, the actual flow rate expression for the i-th cold plate branch is as follows:

[0065] M i =X×mi / (m1+m2+……+mn).

[0066] Furthermore, the relationship between the branch flow rate Mi and the K value on the evaporator side of each cold plate branch is obtained through testing and fitting. Since the heat exchange area A of each cold plate is the same, a KAΔT capacity allocation model can be constructed by combining the temperature difference ΔT between the cold plate and the battery cell to obtain the heat exchange capacity ratio of each cold plate branch. Then, combined with the total cooling capacity of the indoor unit module, the heat exchange capacity of each cold plate branch is obtained.

[0067] qi=Ki*A*△T i ;

[0068] Q i =Q c ×qi / (q1+q2+……+qn);

[0069] Where qi is the proportion of heat exchange capacity for each cold plate branch, and Q is... i The heat exchange capacity of the cold plate corresponding to each cold plate branch.

[0070] S204. Based on the heat exchange of the cold plate corresponding to each cold plate branch, obtain the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch.

[0071] It is understood that, in this embodiment of the present invention, the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch can be obtained by the following formula:

[0072] h i-out =(h ho ×M i +Q i ) / M i .

[0073] S103. Based on the specific enthalpy of the refrigerant in the gaseous state at saturated evaporation pressure, the specific enthalpy of the refrigerant in the liquid state at saturated evaporation pressure, and the specific enthalpy of the refrigerant at the evaporation side outlet of each cold plate branch, obtain the actual refrigerant dryness of each cold plate branch.

[0074] Furthermore, in some embodiments of the present invention, the actual refrigerant dryness of the cold plate branch is obtained by the following formula:

[0075] x=(h i-out -h eva-l ) / (h eva-v -h eva-l ),

[0076] Where x is the actual refrigerant dryness of the i-th cold plate branch, and h i-out h is the specific enthalpy of the refrigerant at the evaporator outlet of the i-th cold plate branch. eva-vh is the specific enthalpy of the refrigerant in gaseous state at saturated evaporation pressure. eva-l It is the specific enthalpy of the refrigerant in liquid state at saturated evaporation pressure.

[0077] S104 When the current operating condition is refrigeration, the refrigerant at the inlet of the regenerator is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled separately to adjust the refrigerant flow of each cold plate branch.

[0078] It should be understood that, compared to costly dryness control schemes that add pressure sensors and flow meters to direct cooling systems, this embodiment of the invention uses multiple temperature sensors (for example, as shown in the figure, temperature sensor T3 determines whether the refrigerant is subcooled after passing through the finned heat exchanger 3; temperature sensor TL calculates the specific enthalpy of the refrigerant after releasing heat from the high-pressure end of the regenerator 5; and temperature sensor Th determines the specific enthalpy of the refrigerant after absorbing heat from the low-pressure end of the regenerator 5, and whether the refrigerant is superheated). These sensors, combined with the aforementioned formulas, calculate the refrigerant flow rate and dryness for each cold plate branch. Then, when the direct cooling system is in cooling mode, the branch control valves of each cold plate branch are controlled based on the refrigerant flow rate and dryness, thereby adjusting the actual refrigerant dryness of each cold plate branch. Thus, by simplifying the refrigerant dryness control parameters, refrigerant dryness control of the direct cooling system is achieved, thereby enabling temperature uniformity control of the battery cell assembly.

[0079] Optionally, in some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, temperature sensor T3 can be installed at the outlet of finned heat exchanger 3, temperature sensor Th can be installed between port c of four-way valve 2 and gas-liquid separator 9, and temperature sensor TL can be installed as follows: Figure 1 The outlet of the main valve 6 shown can also be located between the liquid pipe and the outlet of the main valve 6, as shown in the figure. Figure 2 The inlet of the main valve 6 shown.

[0080] Furthermore, in some embodiments of the present invention, such as Figure 6 As shown, based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled separately, including:

[0081] S301, if the actual refrigerant dryness of the current cold plate branch is greater than the target preset refrigerant dryness, then increase the valve opening of the branch control valve corresponding to the current cold plate branch.

[0082] It is understood that in this embodiment of the present invention, the branch control valve of each cold plate branch can control the refrigerant dryness at the evaporation outlet of the corresponding cold plate branch. Therefore, when the actual refrigerant dryness of the current cold plate branch is greater than the target preset refrigerant dryness, the refrigerant flow rate of the current cold plate branch can be increased and the actual refrigerant dryness of the current cold plate branch can be reduced by increasing the valve opening of the branch control valve corresponding to the current cold plate branch.

[0083] S302, if the actual refrigerant dryness of the current cold plate branch is less than the target preset refrigerant dryness, then reduce the valve opening of the branch control valve corresponding to the current cold plate branch.

[0084] It is understood that, in this embodiment of the present invention, when the actual refrigerant dryness of the current cold plate branch is less than the target preset refrigerant dryness, the refrigerant flow rate of the current cold plate branch can be reduced and the actual refrigerant dryness of the current cold plate branch can be increased by reducing the valve opening of the branch control valve corresponding to the current cold plate branch.

[0085] Furthermore, in some embodiments of the present invention, such as Figure 7 As shown, before controlling the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch, the method further includes:

[0086] S401 obtains the return superheat, exhaust superheat, and subcooling of the refrigerant.

[0087] It is understood that in this embodiment of the present invention, the return gas superheat is the difference between the return gas temperature and the saturated gas temperature at the evaporation pressure, the exhaust superheat is the difference between the exhaust temperature and the saturated gas temperature at the condensation pressure, and the subcooling is the difference between the saturated gas temperature at the condensation pressure and the refrigerant temperature at the condenser outlet.

[0088] S402 controls the main valve and the refrigerant regenerative control valve based on the refrigerant's return superheat, exhaust superheat, and subcooling.

[0089] It is understood that in this embodiment of the present invention, the refrigerant entering the high-pressure chamber of the regenerator can be subcooled by controlling the main valve, and at the same time, the regenerative heat control valve can be controlled to ensure that the direct cooling system has a certain degree of return gas superheat, thereby ensuring system reliability.

[0090] Furthermore, in some embodiments of the present invention, such as Figure 8 As shown, the refrigerant dryness control method for direct cooling systems also includes:

[0091] S501, when the current operating condition is heating, obtains the heat exchange of the regenerator.

[0092] It is understood that in this embodiment of the present invention, when the ambient temperature is low, in order to prevent the battery temperature from being too low and affecting the battery's charging and discharging capacity and lifespan, the battery cell is heated by a heat pump, and the heat exchange of the regenerator is monitored at the same time.

[0093] S502 controls the heat recovery control valve based on the heat exchange capacity of the heat recovery unit.

[0094] It is understood that in this embodiment of the present invention, the heat recovery control valve can be controlled so that the regenerator has a certain amount of heat exchange, thereby consuming the refrigerant superheat specific enthalpy on the compressor outlet side and ensuring that the refrigerant at the cold plate inlet is in a saturated gaseous state. In addition, in the heating mode, the uniformity of refrigerant heat exchange also needs to be considered, and the refrigerant state at the cold plate outlet needs to be controlled to a saturated liquid state. At the same time, considering the temperature error, the control target of refrigerant subcooling should be between 0.5-1℃.

[0095] Furthermore, in some embodiments of the present invention, such as Figure 9 As shown, the refrigerant dryness control method for direct cooling systems also includes:

[0096] S601, obtain the average cell temperature of the cell assembly.

[0097] It is understood that, in this embodiment of the present invention, the temperature of each cell block can be monitored by a temperature sensor to obtain the average cell temperature of the cell block.

[0098] S602 performs frequency regulation control on the compressor based on the average cell temperature of the cell assembly.

[0099] It is understood that in this embodiment of the present invention, under cooling and heating conditions, the average cell temperature of the cell module is controlled by adjusting the frequency of the compressor. For example, when the average cell temperature is greater than the preset upper temperature limit, the compressor frequency is increased, and when the average cell temperature is less than the preset lower temperature limit, the compressor frequency is decreased, thereby ensuring the reliability and stability of each cell module.

[0100] In summary, the refrigerant dryness control method for a direct cooling system proposed in this embodiment of the invention obtains the current operating condition of the direct cooling system, and then obtains the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at the saturated evaporation pressure, as well as the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch. Then, based on the gaseous specific enthalpy, liquid specific enthalpy, and evaporator side outlet of each cold plate branch, the actual refrigerant dryness of each cold plate branch is obtained. Furthermore, when the current operating condition is refrigeration, the refrigerant at the inlet of the regenerator is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled separately to adjust the refrigerant flow rate of each cold plate branch. This simplifies the refrigerant dryness control parameters, achieves refrigerant dryness control of the direct cooling system, and thus achieves temperature uniformity control of the battery cell assembly.

[0101] Based on the refrigerant dryness control method for the direct cooling system in the foregoing embodiments of the present invention, the present invention proposes a computer-readable storage medium storing a refrigerant dryness control program for the direct cooling system. When the refrigerant dryness control program for the direct cooling system is executed by a processor, it implements the refrigerant dryness control method for the direct cooling system described in the foregoing embodiments of the present invention.

[0102] It should be understood that the specific implementation of the computer-readable storage medium in the embodiments of the present invention can be found in the specific implementation of the refrigerant dryness control method of the direct cooling system described in the foregoing embodiments of the present invention. To reduce redundancy, it will not be described again here.

[0103] In summary, the computer-readable storage medium proposed in the embodiments of the present invention can simplify the refrigerant dryness control parameters and realize the refrigerant dryness control of the direct cooling system by executing the refrigerant dryness control program of the direct cooling system stored thereon, thereby realizing the temperature uniformity control of the battery cell assembly.

[0104] Figure 10 This is a block diagram of a refrigerant dryness control device for a direct cooling system according to an embodiment of the present invention.

[0105] Specifically, in some embodiments of the present invention, such as Figure 10 As shown, the refrigerant dryness control device 100 of the direct cooling system includes: a first acquisition module 10, a second acquisition module 20, a third acquisition module 30, and a control module 40.

[0106] The system comprises the following modules: a first acquisition module 10 for acquiring the current operating condition of the direct cooling system; a second acquisition module 20 for acquiring the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and the specific enthalpy of the refrigerant at the evaporator outlet of each cold plate branch; a third acquisition module 30 for acquiring the actual refrigerant dryness of each cold plate branch based on the gaseous specific enthalpy, liquid specific enthalpy, and specific enthalpy of the refrigerant at the saturated evaporation pressure, and the specific enthalpy of the refrigerant at the evaporator outlet of each cold plate branch; and a control module 40 for controlling the branch control valve of each cold plate branch to adjust the refrigerant flow rate of each cold plate branch when the current operating condition is refrigeration and the refrigerant at the inlet of the regenerator is subcooled, based on the actual refrigerant dryness of each cold plate branch.

[0107] Furthermore, in some embodiments of the present invention, the second acquisition module 20 is further configured to: acquire the refrigerant specific enthalpy at the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy at the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system; acquire the total cooling capacity of the indoor unit module based on the refrigerant specific enthalpy at the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy at the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system; acquire the heat exchange capacity ratio of each cold plate branch; acquire the branch cold plate heat exchange capacity corresponding to each cold plate branch based on the total cooling capacity and the heat exchange capacity ratio of each cold plate branch; and acquire the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch based on the branch cold plate heat exchange capacity corresponding to each cold plate branch.

[0108] Furthermore, in some embodiments of the present invention, the third acquisition module 30 is also used to obtain the actual refrigerant dryness of the cold plate branch using the following formula: x = (h i-out -h eva-l ) / (h eva-v -h eva-l ), where x is the actual refrigerant dryness of the i-th cold plate branch, h i-out h is the specific enthalpy of the refrigerant at the evaporator outlet of the i-th cold plate branch. eca-v h is the specific enthalpy of the refrigerant in gaseous state at saturated evaporation pressure. eva-l It is the specific enthalpy of the refrigerant in liquid state at saturated evaporation pressure.

[0109] Furthermore, in some embodiments of the present invention, the control module 40 is also configured to: if the actual refrigerant dryness of the current cold plate branch is greater than the target preset refrigerant dryness, increase the valve opening of the branch control valve corresponding to the current cold plate branch; if the actual refrigerant dryness of the current cold plate branch is less than the target preset refrigerant dryness, decrease the valve opening of the branch control valve corresponding to the current cold plate branch.

[0110] Furthermore, in some embodiments of the present invention, the control module 40 is also used to acquire the return superheat, exhaust superheat and subcooling of the refrigerant; and to control the main valve and the regenerative heat control valve according to the return superheat, exhaust superheat and subcooling of the refrigerant.

[0111] Furthermore, in some embodiments of the present invention, the control module 40 is also used to acquire the heat exchange of the regenerator when the current operating condition is a heating condition; and to control the heat exchange control valve based on the heat exchange of the regenerator.

[0112] Furthermore, in some embodiments of the present invention, the control module 40 is also used to acquire the cell temperature of each cell block; and to perform frequency regulation control on the compressor based on the cell temperature of each cell block.

[0113] It should be understood that the specific implementation of the refrigerant dryness control device of the direct cooling system in the embodiments of the present invention corresponds one-to-one with the specific implementation of the refrigerant dryness control method of the direct cooling system in the foregoing embodiments of the present invention. To reduce redundancy, it will not be described again here.

[0114] In summary, the refrigerant dryness control device for the direct cooling system proposed in this embodiment of the invention acquires the current operating condition of the direct cooling system through a first acquisition module, and then acquires the gaseous specific enthalpy and liquid specific enthalpy of the refrigerant at the saturated evaporation pressure through a second acquisition module, and acquires the refrigerant specific enthalpy at the evaporation side outlet of each cold plate branch; the third acquisition module is used to acquire the actual refrigerant dryness of each cold plate branch based on the gaseous specific enthalpy, the liquid specific enthalpy, and the refrigerant specific enthalpy at the evaporation side outlet of each cold plate branch, and, when the current operating condition is refrigeration condition, the refrigerant at the inlet of the regenerator is subcooled by the control module, and controls the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch to adjust the refrigerant flow rate of each cold plate branch. Therefore, the refrigerant dryness control parameters are simplified, enabling refrigerant dryness control of the direct cooling system, thereby achieving temperature uniformity control of the battery cell assembly.

[0115] Figure 11 This is a block diagram of a direct cooling system according to an embodiment of the present invention.

[0116] Specifically, in some embodiments of the present invention, such as Figure 11 As shown, the direct cooling system 1000 includes the refrigerant dryness control device 100 of the direct cooling system described in the above embodiment of the present invention.

[0117] It should be understood that the specific implementation of the direct cooling system in the embodiments of the present invention can refer to the specific implementation of the refrigerant dryness control method of the direct cooling system in the foregoing embodiments of the present invention. To reduce redundancy, it will not be repeated here.

[0118] In summary, the direct cooling system according to the embodiments of the present invention, by employing the aforementioned refrigerant dryness control device for the direct cooling system, can simplify the refrigerant dryness control parameters, realize the refrigerant dryness control of the direct cooling system, and thereby achieve temperature uniformity control of the battery cell assembly.

[0119] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0120] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0121] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0122] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0123] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0124] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0125] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0126] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling the refrigerant dryness of a direct cooling system, characterized in that, The direct cooling system includes a regenerator, a main valve and a regenerator control valve corresponding to the regenerator, and an indoor unit module. The number of cold plate branches in the indoor unit module corresponds to the number of battery cell modules. Each cold plate branch includes a branch cold plate and a branch control valve. The method includes: Obtain the current operating status of the direct cooling system; Obtain the specific enthalpy of the refrigerant in the gaseous state at saturated evaporation pressure and the specific enthalpy of the refrigerant in the liquid state at saturated evaporation pressure, and obtain the specific enthalpy of the refrigerant at the evaporation side outlet of each cold plate branch; The actual refrigerant dryness of each cold plate branch is obtained based on the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure, the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and the refrigerant specific enthalpy at the evaporation side outlet of each cold plate branch. When the current operating condition is refrigeration, the refrigerant at the inlet of the regenerator is subcooled. Based on the actual refrigerant dryness of each cold plate branch, the branch control valve of each cold plate branch is controlled to adjust the refrigerant flow of each cold plate branch.

2. The refrigerant dryness control method for a direct cooling system according to claim 1, characterized in that, The process of obtaining the refrigerant specific enthalpy at the evaporator-side outlet of each cold plate branch includes: Obtain the refrigerant specific enthalpy on the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy on the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system; The total cooling capacity of the indoor unit module is obtained based on the refrigerant specific enthalpy at the low-pressure inlet side of the regenerator, the refrigerant specific enthalpy at the high-pressure inlet side of the regenerator, and the total refrigerant flow rate of the direct cooling system. Obtain the heat exchange capacity ratio of each cold plate branch, and based on the total cooling capacity and the heat exchange capacity ratio of each cold plate branch, obtain the branch cold plate heat exchange capacity corresponding to each cold plate branch. Based on the heat exchange capacity of the cold plate corresponding to each cold plate branch, the refrigerant specific enthalpy at the evaporator side outlet of each cold plate branch is obtained.

3. The refrigerant dryness control method for a direct cooling system according to claim 1, characterized in that, The actual refrigerant dryness of the cold plate branch can be obtained using the following formula: x=(h i-out -h eva-l ) / (h eva-v -h eva-l ), Where x is the actual refrigerant dryness of the i-th cold plate branch, and h i-out h is the specific enthalpy of the refrigerant at the evaporator outlet of the i-th cold plate branch. eva-v h is the specific enthalpy of the refrigerant in gaseous state at saturated evaporation pressure. eva-l It is the specific enthalpy of the refrigerant in liquid state at saturated evaporation pressure.

4. The refrigerant dryness control method for a direct cooling system according to claim 1, characterized in that, The step of controlling the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch includes: If the actual refrigerant dryness of the current cold plate branch is greater than the target preset refrigerant dryness, then increase the valve opening of the branch control valve corresponding to the current cold plate branch; If the actual refrigerant dryness of the current cold plate branch is less than the target preset refrigerant dryness, then reduce the valve opening of the branch control valve corresponding to the current cold plate branch.

5. The refrigerant dryness control method for a direct cooling system according to claim 4, characterized in that, Before controlling the branch control valve of each branch according to the actual refrigerant dryness of each cold plate branch, the method further includes: Obtain the return superheat, exhaust superheat, and subcooling of the refrigerant; The main valve and the regenerative heat control valve are controlled based on the refrigerant's return superheat, exhaust superheat, and subcooling.

6. The refrigerant dryness control method for a direct cooling system according to claim 1, characterized in that, The method further includes: When the current operating condition is heating condition, the heat exchange capacity of the regenerator is obtained; The heat recovery control valve is controlled based on the heat exchange capacity of the heat recovery unit.

7. The method for controlling refrigerant dryness in a direct-cooling system according to any one of claims 1-6, characterized in that, The method further includes: Obtain the average cell temperature of the cell assembly; The compressor is frequency-controlled based on the average cell temperature of the cell assembly.

8. A computer-readable storage medium, characterized in that, It stores a refrigerant dryness control program for a direct cooling system, which, when executed by a processor, implements the refrigerant dryness control method for a direct cooling system as described in any one of claims 1-7.

9. A refrigerant dryness control device for a direct cooling system, characterized in that, The direct cooling system includes a regenerator, a main valve and a regenerator control valve corresponding to the regenerator, and an indoor unit module. The number of cold plate branches in the indoor unit module corresponds to the number of battery cell modules. Each cold plate branch includes a branch cold plate and a branch control valve. The device includes: The first acquisition module is used to acquire the current operating conditions of the direct cooling system; The second acquisition module is used to acquire the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure and the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and to acquire the specific enthalpy of the refrigerant at the evaporation side outlet of each cold plate branch. The third acquisition module is used to acquire the actual refrigerant dryness of each cold plate branch based on the gaseous specific enthalpy of the refrigerant at saturated evaporation pressure, the liquid specific enthalpy of the refrigerant at saturated evaporation pressure, and the refrigerant specific enthalpy at the evaporation side outlet of each cold plate branch. The control module is used to control the branch control valve of each cold plate branch according to the actual refrigerant dryness of each cold plate branch when the current operating condition is refrigeration condition, so as to adjust the refrigerant flow of each cold plate branch.

10. A direct cooling system, characterized in that, The direct cooling system includes the refrigerant dryness control device for the direct cooling system as described in claim 9.

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