Battery testing apparatus supercooling control device

Abstract

The application discloses a supercooling degree control device of a battery testing equipment. The supercooling degree control device of the battery testing equipment comprises a compressor, a condensing system, a liquid storage tank, a plate heat exchanger, a throttle valve, a temperature sensor, a pressure sensor and a control system; the temperature sensor and the pressure sensor are arranged before an inlet of the throttle valve respectively and are used for detecting temperature and pressure values of refrigerant before the throttle valve in real time and feeding back to the control system; the control system is connected with the condensing system, a water side of the plate heat exchanger, the temperature sensor and the pressure sensor; the control system is used for calculating an actual supercooling degree according to the received real-time temperature and pressure values of the refrigerant before the throttle valve, comparing the actual supercooling degree with a set value, and performing PID adjustment on the condensing system and the water side of the plate heat exchanger according to a deviation, so that the supercooling degree before the throttle valve is constant at the set value. The application can accurately and quickly control the supercooling degree before the throttle valve, so as to meet the performance requirement of the battery testing equipment on the refrigerating system.

Description

Technical Field

[0001] This invention relates to the field of refrigerant phase change refrigeration technology for battery testing equipment, and particularly to a supercooling control device for battery testing equipment. Background Technology

[0002] During battery performance testing, especially under high-power charge and discharge conditions, precise temperature control of the battery pack is required. Refrigerant phase change refrigeration technology is widely used in battery testing equipment due to its high cooling efficiency and wide temperature control range. In traditional battery testing equipment refrigeration systems, condensers and condenser fans are typically used to control the subcooling before the expansion valve. However, this control method has the following technical problems: First, when the subcooling before the valve is controlled by the condenser fan, the response time of the subcooling control is long due to the low heat transfer coefficient on the air side, and the control accuracy is difficult to meet the stringent requirements of battery testing for temperature stability.

[0003] Secondly, the traditional solution adds a liquid receiver tank before the throttle valve. However, since the refrigerant in the liquid receiver tank is not completely filled, the subcooled refrigerant formed after passing through the condenser will experience subcooling loss in the liquid receiver tank, resulting in the inability to form the required subcooling index and affecting the overall performance of the refrigeration system. Summary of the Invention

[0004] This invention provides a supercooling control device for battery testing equipment to solve the problem that the control accuracy of existing devices is difficult to meet the temperature stability requirements of battery testing, and the supercooling before the throttle valve cannot reach the required value.

[0005] According to one aspect of the present invention, a supercooling control device for a battery testing equipment is provided, applied to the refrigerant phase change refrigeration system of the battery testing equipment. The supercooling control device for the battery testing equipment includes: Compressor, condensing system, liquid receiver, plate heat exchanger, expansion valve, temperature sensor, pressure sensor and control system; The compressor inlet is connected to the outlet of the device under test, the compressor outlet is connected to the inlet of the condensation system, and the condensation system outlet is connected to the inlet of the liquid storage tank. The outlet of the liquid storage tank is connected to the refrigerant side inlet of the plate heat exchanger, the refrigerant side outlet of the plate heat exchanger is connected to the inlet of the throttling valve, the water side of the plate heat exchanger is connected to the circulating water system, and the outlet of the throttling valve is connected to the inlet of the device under test. The temperature sensor and the pressure sensor are respectively installed before the inlet of the throttle valve, and are used to detect the temperature and pressure values ​​of the refrigerant before the throttle valve in real time and feed them back to the control system. The control system is connected to the condensing system, the water side of the plate heat exchanger, the temperature sensor, and the pressure sensor. The control system is used to calculate the actual subcooling based on the real-time temperature and pressure values ​​of the refrigerant before the throttle valve, compare the actual subcooling with the set value, and perform PID adjustment on the water side of the condensing system and the plate heat exchanger according to the deviation, so that the subcooling before the throttle valve is kept constant at the set value.

[0006] Optionally, the condensation system includes: a condenser fan and a condenser; The inlet of the condenser is connected to the outlet of the compressor, and the outlet of the condenser is connected to the inlet of the liquid storage tank. The liquid storage tank is used to store the liquid refrigerant after passing through the condenser and to separate the gaseous refrigerant to ensure that the refrigerant entering the plate heat exchanger is liquid. The air inlet of the condenser is connected to the surrounding space, the air outlet of the condenser is connected to the inlet of the condenser fan, and the outlet of the condenser fan is connected to the surrounding space. The control system is used to control the heat exchange capacity of the condenser by adjusting the speed of the condenser fan according to the real-time pressure value of the refrigerant before the valve, thereby adjusting the refrigerant pressure before the throttle valve.

[0007] Optionally, the plate heat exchanger is a water-cooled plate heat exchanger, the water-side inlet of the water-cooled plate heat exchanger is connected to the outlet of the circulating water system, and the water-side outlet of the water-cooled plate heat exchanger is connected to the inlet of the circulating water system, forming a water circulation loop; The control system is used to control the heat exchange of the plate heat exchanger by adjusting the water temperature and flow rate of the circulating water system based on the real-time temperature value of the refrigerant before the valve.

[0008] Optionally, the control system includes a PID controller, which is used to adjust the rotational speed of the condenser fan and the water temperature and flow rate on the water side of the plate heat exchanger based on the deviation between the actual subcooling and the set value.

[0009] Optionally, the supercooling control device for the battery testing equipment also includes: an inlet pressure sensor and an inlet temperature sensor; The inlet pressure sensor and the inlet temperature sensor are respectively installed at the inlet of the device under test. The inlet pressure sensor and the inlet temperature sensor are used to measure the temperature and pressure of the refrigerant at the inlet of the device under test and feed them back to the control system.

[0010] Optionally, the supercooling control device for the battery testing equipment also includes: an outlet temperature sensor and an outlet pressure sensor; The outlet temperature sensor and the outlet pressure sensor are respectively installed at the outlet of the device under test. The outlet temperature sensor and the outlet pressure sensor are used to measure the temperature and pressure of the refrigerant at the outlet of the device under test and feed them back to the control system.

[0011] Optionally, a temperature regulating valve and a flow regulating valve are provided at the water-side inlet of the plate heat exchanger, the temperature regulating valve and the flow regulating valve being used to precisely control the water temperature and flow rate on the water side.

[0012] Optionally, the circulating water system includes a circulating water pump, a water tank, and a temperature control system, wherein the circulating water system is used to provide circulating water for heat exchange to the plate heat exchanger.

[0013] Optionally, the compressor is a variable frequency compressor, which is used to adjust the cooling capacity according to system requirements to adapt to different test conditions; The condenser fan is a variable frequency condenser fan, which is used to adjust the air volume according to system requirements.

[0014] Optionally, the liquid storage tank is a vertically installed cylindrical liquid storage tank, and a liquid level sensor is installed inside the liquid storage tank. The liquid level sensor is used to monitor the liquid level height in the liquid storage tank and control the liquid refrigerant filling degree in the liquid storage tank to meet the requirements.

[0015] The technical solution of this invention provides a subcooling control device for battery testing equipment capable of achieving precise and rapid control of subcooling before the throttling valve. By decoupling the pressure control and temperature control of subcooling, which are independently controlled by the condensing system and the water side of the plate heat exchanger respectively, the control system is simplified and the control accuracy is improved. The condensing system is responsible for regulating the pressure before the valve, and the plate heat exchanger is responsible for regulating the temperature before the valve. The two work together to achieve precise control of subcooling. By separating the pressure control and temperature control of subcooling, which are independently controlled by the condensing system and the water side of the plate heat exchanger respectively, precise and rapid adjustment of the subcooling before the throttling valve is achieved, ensuring that the subcooling before the valve remains constant within the set value deviation range. In summary, this invention solves the problem that the control accuracy of existing devices is insufficient to meet the temperature stability requirements of battery testing, and that the subcooling before the throttling valve cannot reach the required value. It achieves a reasonable structure, high control accuracy, fast response speed, and the ability to meet the stringent performance requirements of battery testing equipment for the refrigeration system.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a battery testing equipment supercooling control device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of another battery testing equipment supercooling control device provided in an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Figure 1 This is a schematic diagram of a supercooling control device for a battery testing equipment according to an embodiment of the present invention. (Refer to...) Figure 1 The present invention provides a supercooling control device for a battery testing equipment, applied to the refrigerant phase change refrigeration system of the battery testing equipment. The supercooling control device for the battery testing equipment includes: 1. Compressor; 2. Condensation system; 3. Liquid receiver; 4. Plate heat exchanger; 5. Throttling valve; 6. Temperature sensor; 7. Pressure sensor; 8. Control system. The inlet of compressor 1 is connected to the outlet of the device under test, the outlet of compressor 1 is connected to the inlet of condensing system 2, and the outlet of condensing system 2 is connected to the inlet of liquid storage tank 3. The outlet of the liquid storage tank 3 is connected to the refrigerant side inlet of the plate heat exchanger 4, the refrigerant side outlet of the plate heat exchanger 4 is connected to the inlet of the throttle valve 5, the water side of the plate heat exchanger 4 is connected to the circulating water system, and the outlet of the throttle valve 5 is connected to the inlet of the device under test. Temperature sensor 6 and pressure sensor 7 are respectively installed before the inlet of throttle valve 5, and are used to detect the temperature and pressure values ​​of the refrigerant before throttle valve in real time and feed them back to control system 8. The control system 8 is connected to the water side of the condensing system 2, the plate heat exchanger 4, the temperature sensor 6, and the pressure sensor 7. The control system 8 is used to calculate the actual subcooling based on the real-time temperature and pressure values ​​of the refrigerant before the throttle valve 5, compare the actual subcooling with the set value, and perform PID regulation on the water side of the condensing system 2 and the plate heat exchanger 4 according to the deviation, so that the subcooling before the throttle valve 5 is kept constant at the set value.

[0022] Specifically, compressor 1 provides the circulating power for the refrigeration system, compressing the low-temperature, low-pressure refrigerant gas into a high-temperature, high-pressure gas. Condensation system 2 maintains the refrigerant pressure within the refrigeration system at a constant level through heat exchange with air. Liquid receiver 3 stores the liquid refrigerant after passing through condensation system 2, regulating the refrigerant circulation flow and reducing the amount of gaseous refrigerant entering throttling valve 5. Plate heat exchanger 4 regulates the refrigerant temperature after passing through liquid receiver 3 by controlling the water temperature and flow rate on the water side, thus controlling the subcooling of the refrigerant before throttling valve 5. Throttling valve 5 regulates the refrigerant circulation flow, thus controlling the superheat of the refrigerant at the outlet of the tested equipment. Temperature sensor 6 measures the refrigerant temperature before throttling valve 5 and feeds it back to control system 8, which adjusts relevant actuators based on the feedback value. Pressure sensor 7 measures the refrigerant pressure before throttling valve 5 and feeds it back to control system 8, which adjusts relevant actuators based on the feedback value. Control system 8 is electrically connected to temperature sensor 6 and pressure sensor 7. Control system 8 receives real-time data from each sensor and performs calculations and processing based on the control algorithm. When temperature and pressure are controlled by different devices, the control is simpler and more precise; when the temperature before the throttle valve 5 is controlled by the plate heat exchanger 4, the temperature stability is better, and because the heat transfer coefficient of water is relatively high compared to air, the response time is faster when combined with the water-side preheating function.

[0023] The working principle of the subcooling control device in battery testing equipment: The high-temperature, high-pressure gaseous refrigerant discharged from compressor 1 undergoes a phase change from gaseous to liquid after passing through condensation system 2. The liquid refrigerant enters storage tank 3. In storage tank 3, due to gravity, the gaseous refrigerant is at the top and the liquid is at the bottom. The lower liquid refrigerant enters plate heat exchanger 4 through a pipe, where it exchanges heat with the water-side circulating water inside plate heat exchanger 4. By controlling the water-side temperature and flow rate, the refrigerant temperature at the outlet of plate heat exchanger 4 is precisely controlled. The pressure before the valve is controlled by condensation system 2. Pressure sensor 7 before throttle valve 5 monitors the real-time pressure value, and temperature sensor 6 before throttle valve 5 monitors the real-time temperature value and feeds it back to control system 8. Control system 8 can calculate and output the subcooling value before the valve in real time based on the pressure and temperature values. By comparing it with the set value, PID adjustment is performed on the condensation system and circulating water system of relevant components according to the deviation to ensure that the subcooling before the valve is always constant within the deviation range of the set value.

[0024] The control system 8 adjusts the fan opening in the condensing system 2 according to the real-time pressure value to control the refrigerant pressure before the throttle valve 5. The water side of the plate heat exchanger 4 is used to connect to the circulating cooling water. The control system 8 adjusts the water temperature or flow rate of the circulating cooling water according to the real-time temperature value to control the refrigerant temperature before the throttle valve 5. By controlling the refrigerant pressure and refrigerant temperature in parallel, the subcooling before the throttle valve 5 is kept constant at the set value. When the battery refrigerant phase change refrigeration mode test is performed, the subcooling control device of the battery test equipment adjusts the fan opening in the condensing system 2 according to the subcooling requirement value before the valve of the tested equipment to ensure that the pressure before the valve of the tested equipment meets the control index requirements. At the same time, the water temperature on the water side of the plate heat exchanger 4 is controlled to ensure that the temperature before the valve of the tested equipment meets the control index requirements. When both the temperature and pressure meet the control index, the subcooling before the valve meets the required value.

[0025] The technical solution of this invention provides a subcooling control device for battery testing equipment capable of achieving precise and rapid control of subcooling before the throttling valve. By decoupling the pressure control and temperature control of subcooling, which are independently controlled by the condensing system and the water side of the plate heat exchanger respectively, the control system is simplified and the control accuracy is improved. The condensing system is responsible for regulating the pressure before the valve, and the plate heat exchanger is responsible for regulating the temperature before the valve. The two work together to achieve precise control of subcooling. By separating the pressure control and temperature control of subcooling, which are independently controlled by the condensing system and the water side of the plate heat exchanger respectively, precise and rapid adjustment of the subcooling before the throttling valve is achieved, ensuring that the subcooling before the valve remains constant within the set value deviation range. In summary, this invention solves the problem that the control accuracy of existing devices is insufficient to meet the temperature stability requirements of battery testing, and that the subcooling before the throttling valve cannot reach the required value. It achieves a reasonable structure, high control accuracy, fast response speed, and the ability to meet the stringent performance requirements of battery testing equipment for the refrigeration system.

[0026] Figure 2 This is a schematic diagram of the supercooling control device for a battery testing apparatus according to an embodiment of the present invention. (Refer to...) Figure 2 Optionally, the condensing system 2 includes: a condensing fan 21 and a condenser 22; The inlet of condenser 22 is connected to the outlet of compressor 1, and the outlet of condenser 22 is connected to the inlet of liquid storage tank 3. Liquid storage tank 3 is used to store the liquid refrigerant after passing through condenser 22 and to separate the gaseous refrigerant to ensure that the refrigerant entering plate heat exchanger 4 is liquid. The air-side inlet of the condenser 22 is connected to the surrounding space, the air-side outlet of the condenser 22 is connected to the inlet of the condenser fan 21, and the outlet of the condenser fan 21 is connected to the surrounding space. The control system 8 is used to control the heat exchange capacity of the condenser 22 by adjusting the speed of the condenser fan 21 according to the real-time pressure value of the refrigerant before the valve, thereby adjusting the refrigerant pressure before the throttle valve 5.

[0027] Specifically, the liquid storage tank 3 stores the liquid refrigerant after passing through the condenser 22 and uses gravity to separate any possible traces of gaseous refrigerant, ensuring that the refrigerant entering the plate heat exchanger 4 is pure liquid. The high-temperature, high-pressure gaseous refrigerant enters the condenser 22, exchanges heat with the air, and condenses into a liquid state. The condenser fan 21 enhances the heat exchange effect on the air side through forced convection, improving condensation efficiency. The condenser fan 21 uses variable frequency control; the control system can adjust its speed as needed, thereby precisely controlling the heat exchange capacity of the condenser 22 and regulating the pressure before the valve.

[0028] By installing a liquid receiver tank after the condenser, it is ensured that the refrigerant entering the plate heat exchanger is in a pure liquid state, thus avoiding the influence of gaseous refrigerant on the heat exchange effect. At the same time, the location of the liquid receiver tank (after the condenser and before the plate heat exchanger) ensures that subcooling is effectively established in the plate heat exchanger, without any loss of subcooling.

[0029] Optionally, the plate heat exchanger is a water-cooled plate heat exchanger, with the water-side inlet of the water-cooled plate heat exchanger connected to the outlet of the circulating water system, and the water-side outlet of the water-cooled plate heat exchanger connected to the inlet of the circulating water system, forming a water circulation loop. The control system is used to control the heat exchange capacity of the plate heat exchanger by adjusting the water temperature and flow rate of the circulating water system based on the real-time temperature value of the refrigerant before the valve.

[0030] Specifically, plate heat exchangers are used to precisely regulate the refrigerant temperature before the expansion valve through heat exchange between the water side and the refrigerant side. Using water-cooled plate heat exchangers to control the valve temperature results in faster temperature control response and better stability because water's heat transfer coefficient is much higher than air. Combined with the preheating function of the circulating water system, the response time during system startup and regulation can be further shortened.

[0031] Optionally, the control system includes a PID controller, which is used to adjust the speed of the condenser fan and the water temperature and flow rate on the water side of the plate heat exchanger according to the deviation between the actual subcooling and the set value.

[0032] Specifically, a PID controller is used to adjust the supercooling deviation in real time, which can quickly respond to system disturbances and stabilize the supercooling within the set value range, thus meeting the high performance requirements of battery testing equipment for the cooling system.

[0033] Optionally, a temperature regulating valve and a flow regulating valve are provided at the water-side inlet of the plate heat exchanger. The temperature regulating valve and the flow regulating valve are used to precisely control the water temperature and water flow on the water side.

[0034] Specifically, a temperature regulating valve and a flow regulating valve are installed at the water-side inlet of the plate heat exchanger, respectively, to finely control the water temperature and flow rate entering the plate heat exchanger, thereby further improving the accuracy of temperature control.

[0035] Continue to refer to Figure 2 The working principle of control system 8 is as follows: First, the control system 8 calculates the saturation temperature at a given pressure based on the temperature value detected by the temperature sensor 6 and the pressure value detected by the pressure sensor 7. Then, it calculates the actual subcooling.

[0036] The control system 8 compares the calculated actual subcooling with the set target subcooling to obtain the deviation value. The PID controller inside the control system adjusts the water side of the condensing system 2 and the plate heat exchanger 4 according to the deviation.

[0037] Specifically, the control of subcooling is decoupled into two independent but coordinated aspects: pressure control and temperature control. The pressure control mechanism works as follows: The control system adjusts the speed of the condenser fan 21 based on the deviation between the real-time pressure value of the pressure sensor 7 before the valve and the target pressure value (which can be set according to the system operating conditions or calculated from the subcooling target value). When the pressure is too high, the speed of the condenser fan 21 is increased to enhance the heat exchange capacity of the condenser 22, causing more refrigerant to condense and thus reducing the system pressure; when the pressure is too low, the speed of the condenser fan 21 is decreased to weaken the heat exchange capacity, causing the pressure to rise again. In this way, the pressure before the valve is stabilized near the target value.

[0038] The temperature control mechanism works as follows: the control system adjusts the water temperature and flow rate on the water side of the plate heat exchanger 4 based on the deviation between the real-time temperature value of the inlet temperature sensor 6 and the target temperature value. Specifically, the water temperature is set by adjusting the temperature control system of the circulating water system, and the water temperature and flow rate entering the plate heat exchanger 4 are controlled by adjusting the opening of the temperature regulating valve and the flow regulating valve. When the inlet temperature is too high, the circulating water temperature is reduced or the water flow rate is increased to enhance the cooling capacity of the plate heat exchanger 4; when the inlet temperature is too low, the circulating water temperature is increased or the water flow rate is decreased to weaken the cooling capacity. In this way, the inlet temperature is precisely controlled at the target value.

[0039] Pressure and temperature control are performed simultaneously, ensuring that the refrigerant state point before the valve is always at the position corresponding to the target subcooling. When the pressure or temperature is disturbed, the control system 8 can respond quickly and restore the system to stability through PID regulation, ensuring that the subcooling before the throttle valve 5 remains constant within the set value deviation range.

[0040] Continue to refer to Figure 2 Optionally, the battery testing equipment supercooling control device further includes: an inlet pressure sensor 91 and an inlet temperature sensor 92; Inlet pressure sensor 91 and inlet temperature sensor 92 are respectively installed at the inlet of the device under test. Inlet pressure sensor 91 and inlet temperature sensor 92 are used to measure the temperature and pressure of the refrigerant at the inlet of the device under test and feed it back to the control system 8.

[0041] Specifically, inlet pressure sensor 91 measures the refrigerant pressure at the inlet of the cold plate (the device under test), and inlet temperature sensor 92 measures the refrigerant temperature at the inlet of the cold plate (the device under test). All the detection signals from these sensors are sent to control system 8 for system monitoring, control, and optimization, thereby achieving comprehensive monitoring of the cooling effect of the device under test.

[0042] Continue to refer to Figure 2 Optionally, the battery testing equipment supercooling control device further includes: an outlet temperature sensor 93 and an outlet pressure sensor 94; The outlet temperature sensor 93 and the outlet pressure sensor 94 are respectively installed at the outlet of the device under test. The outlet temperature sensor 93 and the outlet pressure sensor 94 are used to measure the temperature and pressure of the refrigerant at the outlet of the device under test and feed it back to the control system 8.

[0043] Specifically, outlet temperature sensor 93 measures the refrigerant temperature at the outlet of the cold plate (the device under test) and feeds it back to the control system. The control system then adjusts the relevant actuators based on the feedback value. Outlet pressure sensor 94 measures the refrigerant pressure at the outlet of the cold plate (the device under test) and feeds it back to the control system. The control system then adjusts the relevant actuators based on the feedback value. All the detection signals from these sensors are sent to the control system for system monitoring, control, and optimization, to achieve comprehensive monitoring of the cooling effect of the device under test.

[0044] By installing temperature and pressure sensors at the inlet and outlet of the device under test, respectively, comprehensive monitoring of the cooling effect of the device under test can be achieved, providing data support for system optimization and fault diagnosis.

[0045] Optionally, the circulating water system includes a circulating water pump, a water tank, and a temperature control system, which provides circulating water for heat exchange in the plate heat exchanger.

[0046] Specifically, the circulating water system can provide plate heat exchangers with circulating water of stable temperature and controllable flow rate, ensuring the stability of subcooling control.

[0047] Continue to refer to Figure 2 Optionally, compressor 1 is a variable frequency compressor, which is used to adjust the cooling capacity according to system requirements to adapt to different test conditions; The condenser fan 21 is a variable frequency condenser fan, which is used to adjust the air volume according to the system requirements.

[0048] Specifically, compressor 1 uses a variable frequency compressor, which can adjust the cooling capacity according to system requirements to adapt to different test conditions and load changes. The variable frequency condenser fan can improve the response speed and accuracy of subcooling control.

[0049] Continue to refer to Figure 2 Optionally, the liquid storage tank 3 is a vertically installed cylindrical liquid storage tank. A liquid level sensor is installed inside the liquid storage tank 3 to monitor the liquid level height inside the liquid storage tank and control the liquid refrigerant filling degree of the liquid storage tank to meet the requirements.

[0050] Specifically, the liquid storage tank 3 adopts a vertically installed cylindrical structure and is equipped with a liquid level sensor inside to monitor the liquid level height in the liquid storage tank 3 in real time. The control system 8 can determine whether the refrigerant charge of the system is appropriate based on the liquid level information and make adjustments if necessary to ensure that there is always enough liquid refrigerant at the outlet of the liquid storage tank 3.

[0051] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A supercooling control device for battery testing equipment, applied to the refrigerant phase change refrigeration system of battery testing equipment, characterized in that, include: Compressor, condensing system, liquid receiver, plate heat exchanger, expansion valve, temperature sensor, pressure sensor and control system; The compressor inlet is connected to the outlet of the device under test, the compressor outlet is connected to the inlet of the condensation system, and the condensation system outlet is connected to the inlet of the liquid storage tank. The outlet of the liquid storage tank is connected to the refrigerant side inlet of the plate heat exchanger, the refrigerant side outlet of the plate heat exchanger is connected to the inlet of the throttling valve, the water side of the plate heat exchanger is connected to the circulating water system, and the outlet of the throttling valve is connected to the inlet of the device under test. The temperature sensor and the pressure sensor are respectively installed before the inlet of the throttle valve, and are used to detect the temperature and pressure values ​​of the refrigerant before the throttle valve in real time and feed them back to the control system. The control system is connected to the condensing system, the water side of the plate heat exchanger, the temperature sensor, and the pressure sensor. The control system is used to calculate the actual subcooling based on the real-time temperature and pressure values ​​of the refrigerant before the throttle valve, compare the actual subcooling with the set value, and perform PID adjustment on the water side of the condensing system and the plate heat exchanger according to the deviation, so that the subcooling before the throttle valve is kept constant at the set value.

2. The apparatus according to claim 1, characterized in that, The condensation system includes: a condenser fan and a condenser; The inlet of the condenser is connected to the outlet of the compressor, and the outlet of the condenser is connected to the inlet of the liquid storage tank. The liquid storage tank is used to store the liquid refrigerant after passing through the condenser and to separate the gaseous refrigerant to ensure that the refrigerant entering the plate heat exchanger is liquid. The air inlet of the condenser is connected to the surrounding space, the air outlet of the condenser is connected to the inlet of the condenser fan, and the outlet of the condenser fan is connected to the surrounding space. The control system is used to control the heat exchange capacity of the condenser by adjusting the speed of the condenser fan according to the real-time pressure value of the refrigerant before the valve, thereby adjusting the refrigerant pressure before the throttle valve.

3. The apparatus according to claim 1, characterized in that, The plate heat exchanger is a water-cooled plate heat exchanger. The water-side inlet of the water-cooled plate heat exchanger is connected to the outlet of the circulating water system, and the water-side outlet of the water-cooled plate heat exchanger is connected to the inlet of the circulating water system, forming a water circulation loop. The control system is used to control the heat exchange of the plate heat exchanger by adjusting the water temperature and flow rate of the circulating water system based on the real-time temperature value of the refrigerant before the valve.

4. The apparatus according to claim 2, characterized in that, The control system includes a PID controller, which is used to adjust the rotational speed of the condenser fan and the water temperature and flow rate on the water side of the plate heat exchanger according to the deviation between the actual subcooling and the set value.

5. The apparatus according to claim 1, characterized in that, Also includes: Inlet pressure sensor and inlet temperature sensor; The inlet pressure sensor and the inlet temperature sensor are respectively installed at the inlet of the device under test. The inlet pressure sensor and the inlet temperature sensor are used to measure the temperature and pressure of the refrigerant at the inlet of the device under test and feed them back to the control system.

6. The apparatus according to claim 5, characterized in that, Also includes: Outlet temperature sensor and outlet pressure sensor; The outlet temperature sensor and the outlet pressure sensor are respectively installed at the outlet of the device under test. The outlet temperature sensor and the outlet pressure sensor are used to measure the temperature and pressure of the refrigerant at the outlet of the device under test and feed them back to the control system.

7. The apparatus according to claim 3, characterized in that, The plate heat exchanger is equipped with a temperature regulating valve and a flow regulating valve at the water-side inlet. The temperature regulating valve and the flow regulating valve are used to precisely control the water temperature and water flow on the water side.

8. The apparatus according to claim 3, characterized in that, The circulating water system includes a circulating water pump, a water tank, and a temperature control system. The circulating water system is used to provide circulating water for heat exchange in the plate heat exchanger.

9. The apparatus according to claim 2, characterized in that, The compressor is a variable frequency compressor, which is used to adjust the cooling capacity according to system requirements to adapt to different test conditions; The condenser fan is a variable frequency condenser fan, which is used to adjust the air volume according to system requirements.

10. The apparatus according to claim 1, characterized in that, The liquid storage tank is a vertically installed cylindrical liquid storage tank. A liquid level sensor is installed inside the liquid storage tank to monitor the liquid level height inside the liquid storage tank and control the liquid refrigerant filling degree of the liquid storage tank to meet the requirements.

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