A dual-circulation loop energy storage chiller and thermal management control method

Abstract

The present invention belongs to the technical field of thermal management of battery energy storage systems, and specifically relates to a dual-circulation loop energy storage chiller and a thermal management control method, wherein the dual-circulation loop energy storage chiller is suitable for cooling liquid-cooled battery packs and liquid-cooled energy storage converters PCS, including a battery-side compressor refrigeration circuit and a PCS-side water-to-air heat exchange cooling circuit, and the two circuits can act independently or in parallel to achieve cooling. Its thermal management control method includes: obtaining the operating status of the energy storage system; obtaining the battery cell temperature and water supply temperature; judging whether the PCS-side circuit and the battery-side circuit are put into use according to the operating status of the energy storage system, as well as the battery cell temperature and water supply temperature. The present invention can overcome the problems of high energy consumption of energy storage liquid refrigerators and the inability to completely decouple the battery-side circulating cooling system and the PCS-side circulating cooling system.

Description

Technical Field

[0001] The present invention specifically relates to a double-circulation loop energy storage chiller and a thermal management control method, and belongs to the technical field of thermal management of battery energy storage systems. Background Art

[0002] As energy storage products gradually develop towards large cells, high rates, low noise, and high energy efficiency, liquid-cooled PCS is gradually replacing air-cooled PCS solutions in the field of energy storage products due to its high power, no capacity reduction, low noise, high environmental adaptability, and stable operation. The energy storage liquid-cooled integrated cabinet integrates battery packs, liquid-cooled PCS, high-voltage boxes, thermal management systems, fire protection, etc. It has the outstanding advantages of AC / DC integrated design and distributed layout, and is widely used in industrial and commercial energy storage and energy storage power station projects. At present, a large number of energy storage manufacturers use liquid-cooled PCS in conjunction with liquid-cooled energy storage battery pack solutions, using a single chiller to cool the battery pack and PCS together. Liquid-cooled PCS and liquid-cooled battery packs usually adopt series or parallel solutions, sharing the low-temperature cooling source of the chiller.

[0003] With the application and experimental research of energy storage liquid cooling system engineering, the above thermal management solutions have gradually exposed some problems. The heat generating element in the liquid cooling PCS, the insulated gate bipolar transistor IGBT (hereinafter referred to as IGBT), has the characteristics of small specific heat, no heat storage, and large instantaneous heat generation. There are large differences in physical parameters and working characteristics between IGBT and battery cells, and there are also large differences in the required cooling capacity and cooling temperature.

[0004] Since the optimal operating temperature of the battery cell is between 25 and 35°C, the cooling temperature required for liquid-cooled battery packs is generally controlled at 18°C; while liquid-cooled PCS needs to consider the IGBT junction temperature during the charging and discharging process, and generally the liquid supply temperature is controlled below 60°C to meet the cooling needs. The cooling temperatures required by the two are very different, and sharing the same low-temperature cold source provided by the chiller will lead to a waste of cooling capacity and affect the overall energy efficiency of the system.

[0005] Due to the instantaneous heating characteristics of PCS, the liquid-cooled PCS needs to be cooled down in time during the charging and discharging process. However, due to the high specific heat of the battery cell, if the battery cell temperature is appropriate during the charging and discharging process, the cooling function can be disabled. When the liquid cooling cabinet is in a static state and the battery cell temperature exceeds the limit, the chiller still needs to be started to meet the cooling or heating requirements; under static conditions, the liquid-cooled PCS does not need to perform any action due to no power reasons. There is also a large difference in the cooling time period required for the two. If the same cold source is shared, the chiller operation time will inevitably increase and the system operation energy efficiency will be reduced.

[0006] Although the conventional single-loop chiller can provide cold sources for the liquid-cooled PCS and liquid-cooled battery pack respectively through series or parallel loops, the two cannot be completely decoupled, which will inevitably lead to prolonged chiller operation time and waste of chiller cooling capacity, seriously affecting the overall operating efficiency of the machine and contrary to the development direction of high energy efficiency.

[0007] Based on the above pain points, the present invention innovatively provides a dual-circuit energy storage chiller to achieve complete decoupling of the battery side refrigeration circuit and the PCS side refrigeration circuit. According to the cooling requirements of the battery pack and PCS, the two circuits can act independently, reducing the chiller's operating time, avoiding waste of cooling capacity, and completely solving the problem of high energy consumption of energy storage liquid refrigerators. Summary of the invention

[0008] The purpose of the present invention is to provide a dual-circulation loop energy storage chiller and a thermal management control method to overcome the problems of high energy consumption of energy storage liquid refrigerators and the inability to completely decouple the battery side circulation cooling system and the PCS side circulation cooling system.

[0009] In order to achieve the above object, the first technical solution of the present invention is: a dual-circuit energy storage chiller, the innovation of which is that it includes a battery side compressor refrigeration circuit and a PCS side water-air heat exchange circuit that can operate independently or in parallel,

[0010] The battery side compressor refrigeration circuit is connected to the liquid-cooled battery pack cold plate to form a circulation circuit for always providing constant temperature cooling water for the liquid-cooled battery pack.

[0011] The battery side compressor refrigeration circuit includes a battery side cold cycle system and a refrigeration cycle system. The battery side cold cycle system and the refrigeration cycle system realize refrigeration through heat exchange of an evaporator.

[0012] The water-air heat exchange circuit on the PCS side is connected to the PCS cold plate to form a circulation circuit, and the forced convection heat exchange principle is always used to realize water-air heat exchange, which is used to cool the liquid-cooled energy storage converter PCS.

[0013] The battery side cold cycle system and the PCS side water-air heat exchange circuit are provided with branch circuits, and an electric two-way valve and an electric three-way valve are provided on the branch circuits. The two sides can be operated independently or in parallel by relying on different actions of the electric two-way valve and the electric three-way valve. When the electric two-way valve and the electric three-way valve are in a closed state, the circuits on both sides can be operated independently; when the electric two-way valve and the electric three-way valve are in an open state, the circuits on both sides can be operated in parallel.

[0014] The battery side compressor refrigeration circuit and the PCS side water-to-air heat exchange circuit share the same set of heat exchange fans to perform heat exchange on the heat exchanger core, and the battery side compressor refrigeration circuit and the PCS side water-to-air heat exchange circuit share a set of pressure stabilization system to achieve circuit buffering and pressure stabilization.

[0015] In the above-mentioned first technical scheme, the battery side cooling circulation system includes a battery side water pump and a heater, the inlet of the battery side water pump is connected to the liquid-cooled battery pack cold plate outlet pipeline, and a first temperature sensor and a first pressure sensor for monitoring the return liquid temperature and pressure of the cooling water in the pipe are provided near the inlet of the pipeline, the outlet of the battery side water pump flows into the second valve port through the first valve port of the electric three-way valve and is connected to the inlet end of the heater, the outlet end of the heater is connected to the first inlet end of the evaporator, the third valve port of the electric three-way valve is connected to the water-to-air heat exchange circuit on the PCS side, the first outlet pipeline of the evaporator is connected to the inlet pipeline of the liquid-cooled battery pack cold plate, and a second temperature sensor and a second pressure sensor for monitoring the supply liquid temperature and pressure of the cooling water in the pipe are provided on the pipeline.

[0016] In the above-mentioned first technical solution, the refrigeration cycle system includes a compressor, a throttling device, a drying filter and a condenser. The second outlet of the evaporator is connected to the inlet of the condenser through the compressor. The outlet of the condenser is connected to the second inlet pipeline of the evaporator, and the drying filter and the throttling device are connected in series on the pipeline.

[0017] In the above-mentioned first technical scheme, the PCS side water-to-air heat exchange circuit includes a PCS side water pump and a water-to-air heat exchanger core. The water inlet of the PCS side water pump is connected to the outlet pipeline of the PCS cold plate, and a third temperature sensor for monitoring the return liquid temperature of the cooling water in the pipe is provided on the pipeline. The water outlet of the PCS side water pump is connected to the inlet pipeline of the PCS cold plate through the water-to-air heat exchanger core, and a fourth temperature sensor and a third pressure sensor for monitoring the supply liquid temperature and pressure of the cooling water in the pipe are provided on the pipeline. An ambient temperature sensor is also provided at the air inlet position of the water-to-air heat exchanger core to monitor the inlet air temperature.

[0018] In the first technical solution mentioned above, the pressure stabilizing system includes an expansion tank, and the pressure stabilizing port of the expansion tank is simultaneously connected to the battery side cooling circulation circuit and the PCS side water-air heat exchange circuit to ensure that both sides have the same system back pressure.

[0019] In the above-mentioned first technical solution, a liquid filling and discharge port is provided in the pipeline of the battery side cooling circulation system.

[0020] In order to achieve the above purpose, the second technical solution of the present invention is: a thermal management control method of the dual-circuit energy storage chiller according to the above-mentioned dual-circuit energy storage chiller, the innovation of which is: comprising a dual-circuit energy storage chiller, and serving as the core thermal management control system in the energy storage liquid cooling integrated cabinet, for real-time control of the battery cell temperature under any working condition and the IGBT temperature in the PCS, the dual-circuit energy storage chiller is issued action instructions and working modes in real time by the battery energy management system BMS, and at the same time, the battery energy management system BMS pre-sets the battery cell temperature of the liquid-cooled battery pack to start cooling as T BAT_COOL , the cell temperature T of the liquid-cooled battery pack when starting heating BAT_HEAT , and the upper limit temperature of the liquid supply of the liquid-cooled PCS T pcs_max , the specific thermal management steps are as follows:

[0021] Step S1: When the energy storage liquid cooling integrated cabinet is in the charging and discharging stage,

[0022] Step S11: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The water-air heat exchange circuit on the PCS side is in operation mode, and the compressor refrigeration circuit on the battery side is in standby mode.

[0023] Step S12: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , the water-air heat exchange circuit on the PCS side is in operation mode, and the compressor refrigeration circuit on the battery side is in cooling mode.

[0024] Step S13: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , the water-air heat exchange circuit on the PCS side is in operation mode, and the compressor refrigeration circuit on the battery side is in heating mode.

[0025] Step S2: When the energy storage liquid cooling integrated cabinet is in the static stage,

[0026] Step S21: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , the water-air heat exchange circuit on the PCS side is in standby mode, and the compressor refrigeration circuit on the battery side is in cooling mode.

[0027] Step S22: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , the water-air heat exchange circuit on the PCS side is in standby mode, and the compressor refrigeration circuit on the battery side is in heating mode.

[0028] Step S23: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The water-to-air heat exchange circuit on the PCS side is in standby mode, and the compressor refrigeration circuit on the battery side is in standby mode.

[0029] In the above second technical solution, when the battery side compressor refrigeration circuit is in standby mode, all components of the battery side compressor refrigeration circuit are not in operation;

[0030] When the battery side compressor refrigeration circuit is in the refrigeration mode, the battery side water pump in the circuit is running, the compressor and the heat exchange fan automatically adjust the operating frequency according to the target temperature, and the throttling device automatically adjusts the valve opening to match the required heat load according to the refrigerant pressure.

[0031] When the battery side compressor refrigeration circuit is in heating mode, the battery side water pump is running, and the heater in the battery side cold cycle system determines whether to execute the heating command based on the real-time battery side liquid supply temperature collected by the second temperature sensor on the battery side and the heater start-stop setting value.

[0032] When the battery side compressor refrigeration circuit is in the self-circulation mode, only the battery side water pump operates, and the other components do not operate.

[0033] In the above second technical solution, when the water-air heat exchange circuit on the PCS side is in standby mode, and the water pump on the PCS side is in standby mode,

[0034] When the PCS side water-to-air heat exchange circuit is in the operation mode, and the PCS side water pump it has is running, and based on the PCS side liquid supply temperature collected in real time by the fourth temperature sensor, the PCS side liquid supply temperature is matched with the target water temperature through the frequency conversion adjustment of the heat exchange fan.

[0035] In the above second technical solution, when the dual-circulation loop energy storage chiller is in an ambient temperature condition of -5~45°C, the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit operate independently. At this time, the electric two-way valve and the electric three-way valve between the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit are both kept closed;

[0036] When the dual-circulation loop energy storage chiller is in a low ambient temperature condition below -5°C and a high ambient temperature condition above 45°C, the battery side compressor refrigeration circuit and the PCS side water-to-air heat exchange circuit operate in parallel. At this time, the electric two-way valve and the electric three-way valve are both kept open.

[0037] In the second technical solution, in step S1, if the ambient temperature is greater than 45°C and the actual liquid supply temperature T pcs More than T pcs_maxThe water-air heat exchange circuit on the PCS side maintains the running mode. At this time, the high-temperature mixed water mode is triggered, that is, the battery side compressor refrigeration circuit switches to the refrigeration mode, and the low-temperature coolant of the liquid-cooled battery pack flows into the water-air heat exchange circuit on the PCS side and mixes with the high-temperature fluid of the liquid-cooled PCS. The liquid supply temperature of the water-air heat exchange circuit on the PCS side is reduced by mixing the low-temperature cold source, so that it always provides the liquid-cooled PCS with a cold source whose liquid temperature meets the set requirements.

[0038] If the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit is in cooling mode, and the low-temperature mixed water mode is triggered. That is, the electric two-way valve between the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit is in a fully open state, and the electric three-way valve is half-opened, so that the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit.

[0039] In the above-mentioned second technical solution, in step S2, if the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit is in the refrigeration mode, and the low-temperature mixed water mode is triggered at this time, that is, the PCS side water-air heat exchange circuit is switched to the operation mode, and the electric two-way valve arranged between the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit is in a fully open state, and the electric three-way valve is opened half-open, so that the battery side compressor refrigeration circuit and the PCS side water-air heat exchange circuit are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit.

[0040] The positive effect of the present invention is that after adopting the dual-circulation loop energy storage chiller and the thermal management control method of the present invention, the dual-circulation loop energy storage chiller includes a battery side compressor refrigeration circuit and a PCS side water-air heat exchange circuit that can operate independently or in parallel.

[0041] The battery side compressor refrigeration circuit is connected to the liquid-cooled battery pack cold plate to form a circulation circuit for always providing constant temperature cooling water for the liquid-cooled battery pack.

[0042] The battery side compressor refrigeration circuit includes a battery side cold cycle system and a refrigeration cycle system. The battery side cold cycle system and the refrigeration cycle system realize refrigeration through heat exchange of an evaporator.

[0043] The water-air heat exchange circuit on the PCS side is connected to the PCS cold plate to form a circulation circuit, and the forced convection heat exchange principle is always used to realize water-air heat exchange, which is used to cool the liquid-cooled energy storage converter PCS.

[0044] For the chiller thermal management control method, the operating mode of the water-to-air heat exchange circuit on the PCS side and the compressor refrigeration circuit on the battery side is determined according to the current state of the energy storage liquid cooling integrated cabinet and the actual temperature of the battery cell;

[0045] The design advantages of the present invention are:

[0046] 1) System configuration innovation: The present invention provides a new chiller technology route. The dual-circuit chiller is equipped with a battery-side compressor refrigeration circuit and a PCS-side water-to-air heat exchange circuit to meet the cooling needs of the battery side and the PCS side, respectively, to achieve thermal management decoupling of the battery side and the PCS side. The PCS-side water-to-air heat exchange circuit adopts forced natural convection heat exchange, which saves more than 70% energy compared to the fluorine cooling solution. The battery-side compressor refrigeration circuit can choose a fluorine cooling configuration solution with smaller cooling demand and lower energy consumption, to achieve high efficiency and energy saving.

[0047] 2) Innovation of energy-saving control scheme: The present invention provides an energy-saving control scheme for a dual-circuit energy storage chiller. The chiller can receive and execute action instructions and related fixed values ​​issued by the BMS in real time to achieve efficient energy-saving control. The energy-saving control scheme provided by the present invention should reduce the overall action time of the battery side water circuit by about 20% and the overall action time of the PCS side water circuit by about 20% for typical charge and discharge operating conditions (0.5C full charge and discharge + static cooling).

[0048] In summary, the present invention relies on the dual-circuit chiller system configuration innovation and energy-saving control scheme to achieve complete decoupling of the battery side refrigeration circuit and the PCS side refrigeration circuit. According to the cooling requirements of the battery pack and PCS, the two circuits can act independently, reducing the chiller action time, avoiding the waste of cooling capacity, and greatly reducing the comprehensive energy consumption of the energy storage liquid refrigerator system. Combined with the actual charging and discharging operating conditions, the comprehensive energy consumption is reduced by 40%. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a structural schematic diagram of a specific implementation mode of the chiller of the present invention;

[0050] Figure 2 This is the principle diagram of independent action on both sides under normal temperature conditions;

[0051] Figure 3 This is a schematic diagram of high temperature water mixing of the chiller of the present invention;

[0052] Figure 4 This is a schematic diagram of low-temperature water mixing of the chiller of the present invention;

[0053] Figure 5 It is a schematic diagram of the chiller management control process of the present invention;

[0054] Figure 6 It is a logic flow chart of low-temperature mixed water judgment action of the battery side liquid cooling circuit of the present invention;

[0055] Figure 7 It is a logic flow chart of the high temperature mixed water judgment action of the liquid cooling circuit on the PCS side of the present invention;

[0056] Figure 8 This is another double-circuit water mixing method provided by the present invention. DETAILED DESCRIPTION

[0057] The present invention is further described below with reference to the accompanying drawings and given embodiments, but is not limited thereto.

[0058] Example 1

[0059] like Figure 1 , 2 As shown, a dual-circuit energy storage chiller includes a battery-side compressor refrigeration circuit 10 and a PCS-side water-air heat exchange circuit 20 that can operate independently or in parallel.

[0060] The battery side compressor refrigeration circuit 10 is connected to the liquid-cooled battery pack cold plate 70 to form a circulation circuit for always providing constant temperature cooling water for the liquid-cooled battery pack.

[0061] The battery side compressor refrigeration circuit 10 includes a battery side cooling circulation system 100 and a refrigeration circulation system 110. The battery side cooling circulation system 100 and the refrigeration circulation system 110 perform heat exchange with each other through an evaporator 120 to achieve refrigeration.

[0062] The PCS side water-air heat exchange loop 20 is connected with the PCS cold plate 80 to form a circulation loop, and always uses the forced convection heat exchange principle to realize water-air heat exchange, which is used to cool the liquid-cooled energy storage converter PCS.

[0063] The battery side cold cycle system 100 and the PCS side water-air heat exchange circuit 20 are provided with a branch circuit, and an electric two-way valve 40 and an electric three-way valve 50 are provided on the branch circuit, and the two sides can be operated independently or in parallel by relying on the different actions of the electric two-way valve 40 and the electric three-way valve 50. When the electric two-way valve 40 and the electric three-way valve 50 are in a closed state, the circuits on both sides can be operated independently; when the electric two-way valve 40 and the electric three-way valve 50 are in an open state, the circuits on both sides can be operated in parallel.

[0064] The battery side compressor refrigeration circuit 10 and the PCS side water-to-air heat exchange circuit 20 share the same set of heat exchange fans 60 for water-to-air heat exchanger core heat exchange, and the battery side compressor refrigeration circuit 10 and the PCS side water-to-air heat exchange circuit 20 share a set of pressure stabilization system 30 to achieve circuit buffering and pressure stabilization.

[0065] The operation of the electric two-way valve 40 in Example 1 is as follows:

[0066] The valve ports of the electric two-way valve 40 are connected to the D waterway and the E waterway respectively to control the flow of the D and E waterways. When the electric two-way valve 40 is in a closed state, no coolant flows in the D and E waterways. When the electric two-way valve 40 is in an open state, the D and E waterways resume flow.

[0067] The operation of the electric three-way valve 50 is as follows: the valve ports of the electric three-way valve are respectively connected to water channel A, water channel B, and water channel C to control the flow of water channels A, B, and C. The electric three-way valve 50 has an opening adjustment function of 0~180°. When the electric three-way valve 50 is in a fully closed state with an opening of 0°, the coolant can only flow from water channel A to water channel B. When the electric three-way valve 50 is in a fully open state with an opening of 180°, the coolant can only flow from water channel A to water channel C. When the electric three-way valve is at any opening between 0~180°, part of the coolant flows from water channel A to water channel B, and part of the coolant flows from water channel A to water channel C.

[0068] When the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 are operated independently, that is, the electric two-way valve 40 is in a closed state, and the electric three-way valve 50 is in a fully closed state, the coolant can only flow from the A water path to the B water path, and the D water path is completely isolated from the E water path. The battery side cold cycle system 100 and the PCS side water-air heat exchange circuit 20;

[0069] When the battery side compressor refrigeration circuit 10 and the PCS side water-to-air heat exchange circuit 20 are operated in parallel, that is, the electric two-way valve 40 is in an open state, and the electric three-way valve 50 is at an opening between 0 and 180 degrees, part of the coolant in the battery side cold circulation system 100 flows from water path A to water path B, part of the coolant flows from water path A to water path C and enters the PCS side water-to-air heat exchange circuit 20, and part of the coolant flows into the PCS side water path heat exchange circuit 20 and then flows to water path E via water path D, and returns to the battery side cold circulation system 100 to complete the circulation.

[0070] like Figure 1As shown, in order to further optimize the structure, the battery side cooling circulation system 100 includes a battery side water pump 101 and a heater 102, the inlet of the battery side water pump 101 is connected to the outlet pipeline of the liquid-cooled battery pack cold plate, and a first temperature sensor 103 and a first pressure sensor 104 for monitoring the return liquid temperature and pressure of the cooling water in the pipe are provided near the inlet of the pipeline, the outlet of the battery side water pump 101 flows into the second valve port through the first valve port of the electric three-way valve 50 and is connected to the inlet end of the heater 102, the outlet end of the heater 102 is connected to the first inlet end of the evaporator 120, the third valve port of the electric three-way valve 50 is connected to the PCS side water-air heat exchange circuit 20, the first outlet pipeline of the evaporator 120 is connected to the inlet pipeline of the liquid-cooled battery pack cold plate, and a second temperature sensor 105 and a second pressure sensor 106 for monitoring the supply liquid temperature and pressure of the cooling water in the pipe are provided on the pipeline.

[0071] like Figure 1 As shown, in order to realize the refrigeration cycle, the refrigeration cycle system 110 includes a compressor 111, a throttling device 112, a drying filter 113 and a condenser 114. The second outlet of the evaporator 120 is connected to the inlet of the condenser 114 through the compressor 111, and the outlet of the condenser 114 is connected to the second inlet pipeline of the evaporator 120, and the drying filter 113 and the throttling device 112 are connected in series on the pipeline.

[0072] In the present embodiment, the refrigerant used in the battery side cold circulation system 100 is also coolant. The battery side water pump 101 provides circulation power for the battery side cold circulation system. The battery side cold circulation system 100 is provided with a PTC electric heater. When the temperature of the battery cell is low, the heater can be started to heat up the battery cell to always maintain a suitable temperature of the battery cell. The compressor 111 provides power for the refrigeration circulation system, and the evaporator 120 can bring the cold energy of the refrigeration circulation system 110 into the battery side cold circulation system 100.

[0073] The refrigerant used in the refrigeration cycle system in this embodiment is Freon.

[0074] like Figure 1As shown, in order to realize complete decoupling on the PCS side, the PCS side water-to-air heat exchange circuit 20 includes a PCS side water pump 201 and a water-to-air heat exchanger core 202. The water inlet of the PCS side water pump 201 is connected to the outlet pipeline of the PCS cold plate, and a third temperature sensor 203 for monitoring the return liquid temperature of the cooling water in the pipe is provided on the pipeline. The water outlet of the PCS side water pump 201 is connected to the inlet pipeline of the PCS cold plate through the water-to-air heat exchanger core 202, and a fourth temperature sensor 204 and a third pressure sensor 205 for monitoring the supply liquid temperature and pressure of the cooling water in the pipe are provided on the pipeline. An ambient temperature sensor 206 is also provided at the air inlet position of the water-to-air heat exchanger core 202 to monitor the inlet air temperature.

[0075] In this embodiment, the refrigerant used in the water-to-air heat exchange loop 20 on the PCS side is coolant. The water pump 201 on the PCS side provides circulation power for the water-to-air heat exchange loop on the PCS side. The coolant passes through the PCS side and is pressurized by the water pump and flows into the water-to-air heat exchanger core 202. The heat exchange fan 60 realizes the forced air cooling convection heat exchange function, and the coolant temperature is reduced. The coolant flowing out of the water-to-air heat exchanger core flows into the PCS cold plate to realize the cooling function of the IGBT.

[0076] like Figure 1 As shown, the pressure stabilizing system 30 includes an expansion tank 300, and the pressure stabilizing port of the expansion tank 300 is connected to the battery side cooling circulation loop 100 and the PCS side water-air heat exchange loop 20 at the same time, so as to ensure that both sides have the same system back pressure, and a throttling orifice plate 301 is also provided on the pressure stabilizing port pipeline of the expansion tank 300 to prevent water from flowing through the two sides. Specifically, the pressure stabilizing port of the expansion tank 300 is connected to the inlet of the battery side water pump 101 and the PCS side water pump 201 at the same time, so as to ensure the same system back pressure of the battery side cooling circulation loop 100 and the PCS side water-air heat exchange loop 20. Due to the difference in performance between the battery side water pump 101 and the PCS side water pump 201, the independence of the two circuits is ensured.

[0077] To further illustrate Example 1, relying on the unique properties of the dual-circuit chiller, an efficient and energy-saving control scheme for energy storage liquid refrigerators is formulated. If the battery cell temperature is appropriate during the charging and discharging stage, the water-air heat exchange circuit 20 on the PCS side cools the PCS in the operating mode, and the battery side compressor refrigeration circuit 10 does not need to act; if the battery cell temperature is overheated during the charging and discharging stage, the water-air heat exchange circuit 20 on the PCS side cools the PCS in the operating mode, and the battery side compressor refrigeration circuit 10 adopts the refrigeration mode to provide a constant temperature cold source for cooling the battery pack; if the battery cell temperature is overheated during the static stage, only the battery side compressor refrigeration circuit 10 acts, and the refrigeration mode is executed to cool the battery cell; if the battery cell temperature is appropriate during the static stage, both circuits remain in standby mode; if the battery cell temperature is too low during the static stage, the water-air heat exchange circuit 20 on the PCS side maintains the standby mode, and the battery side compressor refrigeration circuit 10 executes the heating mode, starting the water circuit water pump and heater to heat the battery cell.

[0078] Furthermore, the dual-circulation loop energy storage chiller is provided with dual water temperature control targets, namely the PCS side target water temperature and the battery side target water temperature. The battery side compressor refrigeration loop 10 has a higher priority than the PCS side water-to-air heat exchange loop 20 for refrigeration target water temperature, which can ensure that the battery side compressor refrigeration loop 10 always provides a cold source with suitable temperature. If the battery side compressor refrigeration loop 10 is in refrigeration mode, regardless of whether the PCS side water-to-air heat exchange loop 20 is in operation, the heat exchange fan, compressor, etc. perform PID adjustment according to the battery side target water temperature to ensure high temperature control accuracy. If the battery side compressor refrigeration loop 10 is in standby mode, the PCS side target water temperature in the PCS side water-to-air heat exchange loop 20 is used as the control target to realize variable frequency speed control of the heat exchange fan to ensure the target water temperature control accuracy.

[0079] Furthermore, considering the low specific heat characteristics of IGBT in the energy storage inverter, in order to prevent the PCS module from overheating and tripping, the liquid supply temperature on the PCS side must always be lower than a certain limit level. In response to extreme high temperature weather conditions, due to the reduced temperature difference between water and air heat exchange and the limited heat exchange area, the water-to-air heat exchanger core 202 and the heat exchange fan 60 cannot provide a cold source with a suitable liquid temperature. In order to improve the temperature resistance of the chiller, the electric three-way valve 50 and the electric two-way valve 40 are used to achieve automatic water mixing and closing on both sides.

[0080] Example 2

[0081] like Figures 3 to 7As shown, a dual-circulation loop energy storage chiller thermal management control method includes a dual-circulation loop energy storage chiller, and serves as a core thermal management control system in an energy storage liquid cooling integrated cabinet, which is used to control the battery cell temperature and the IGBT temperature in the PCS in real time under any working conditions. The dual-circulation loop energy storage chiller is issued action instructions and working modes in real time by the battery energy management system BMS. At the same time, the battery energy management system BMS pre-sets the battery cell temperature of the liquid-cooled battery pack to start cooling as T BAT_COOL , the cell temperature T of the liquid-cooled battery pack when starting heating BAT_HEAT , and the upper limit temperature of the liquid supply of the liquid-cooled PCS T pcs_max , the specific thermal management steps are as follows:

[0082] Step S1: When the energy storage liquid cooling integrated cabinet is in the charging and discharging stage,

[0083] Step S11: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The PCS side water-air heat exchange circuit 20 is in operation mode, and the battery side compressor refrigeration circuit 10 is in standby mode.

[0084] Step S12: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , then the PCS side water-air heat exchange circuit 20 is in operation mode, and the battery side compressor refrigeration circuit 10 is in cooling mode,

[0085] Step S13: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , then the PCS side water-air heat exchange circuit 20 is in the running mode, and the battery side compressor refrigeration circuit 10 is in the heating mode,

[0086] Step S2: When the energy storage liquid cooling integrated cabinet is in the static stage,

[0087] Step S21: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , the PCS side water-air heat exchange circuit 20 is in standby mode, and the battery side compressor refrigeration circuit 10 is in cooling mode.

[0088] Step S22: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , the PCS side water-air heat exchange circuit 20 is in standby mode, and the battery side compressor refrigeration circuit 10 is in heating mode.

[0089] Step S23: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The PCS side water-air heat exchange circuit 20 is in standby mode, and the battery side compressor refrigeration circuit 10 is in standby mode.

[0090] The battery side compressor refrigeration circuit 10 of the present invention has different working modes of standby, refrigeration, self-circulation and heating, and the PCS side water-air heat exchange circuit 20 has two different working modes of standby and operation. The specific modes of the circuits on both sides are:

[0091] When the battery side compressor refrigeration circuit 10 is in standby mode, all components of the battery side compressor refrigeration circuit 10 are not in operation;

[0092] When the battery side compressor refrigeration circuit 10 is in the cooling mode, the battery side water pump 101 in the circuit is running, the compressor 111 and the heat exchange fan 60 automatically adjust the operating frequency according to the target temperature, and the throttling device 112 automatically adjusts the valve opening to match the required heat load according to the refrigerant pressure.

[0093] Specifically, the refrigeration cycle system 110 and the battery side cold cycle system 100 are both kept in working state. The compressor 111 in the refrigeration cycle system 110 is turned on according to the target water temperature setting value to realize the phase change heat transfer on the fluorine side. The heat exchange fan 60 is PID-adjusted by the temperature collected by the ambient temperature sensor 206 and the expected condensing temperature. The expected condensing temperature is a set value that can be adjusted. The chiller determines whether to exit the refrigeration mode according to the supply and return liquid temperature. The battery side water pump 101 in the battery side cold cycle system 100 is actuated, and the coolant in the battery side cold cycle system 100 is provided with circulation power by the battery side water pump 101, and the cooling function is realized through the evaporator 120.

[0094] When the battery side compressor refrigeration circuit 10 is in the heating mode, the battery side water pump 101 is running, and the heater 102 in the battery side cold cycle system 100 determines whether to execute the heating command based on the real-time battery side liquid supply temperature collected by the second temperature sensor 105 on the battery side and the heater start-stop setting value.

[0095] When the battery side compressor refrigeration circuit 10 is in the self-circulation mode, only the battery side water pump 101 is in operation, and the other components are inactive. The refrigeration cycle system 110 maintains a standby state, and the battery side water pump 101 continuously provides a power source for the battery circuit coolant to realize the self-circulation function of the cooling water.

[0096] When the PCS side water-air heat exchange circuit 20 is in standby mode, and the PCS side water pump 201 it has is in standby mode,

[0097] When the PCS side water-air heat exchange circuit 20 is in the operation mode, and the PCS side water pump 201 it has is running, and based on the PCS side liquid supply temperature collected in real time by the fourth temperature sensor 204, the PCS side liquid supply temperature is matched with the target water temperature through the heat exchange fan 60 according to the frequency conversion regulation.

[0098] In summary, the BMS determines the operating status of the energy storage liquid cooling integrated cabinet in real time. According to the charging and discharging stage and the static stage, the BMS sends multiple working modes and execution settings to the dual-circulation loop chiller.

[0099] 1) When the liquid cooling cabinet is in the charging and discharging stage, if the battery cell temperature is appropriate, the water-air heat exchange circuit 20 on the PCS side is in the operating mode, and the compressor refrigeration circuit 10 on the battery side is in the standby mode;

[0100] 2) When the liquid cooling cabinet is in the charging and discharging stage, if the battery cell temperature is over-temperature, the water-air heat exchange loop 20 on the PCS side is in the operating mode, and the compressor refrigeration loop 10 on the battery side is in the cooling mode;

[0101] 3) When the liquid cooling cabinet is in the static stage, if the battery cell temperature is overheated, the water-air heat exchange circuit 20 on the PCS side is in the standby mode, and the battery side compressor refrigeration circuit 10 is in the cooling mode;

[0102] 4) When the liquid cooling cabinet is in the static stage, if the battery cell temperature is too low, the water-air heat exchange circuit 20 on the PCS side is in the standby mode, and the battery side compressor refrigeration circuit 10 is in the heating mode;

[0103] 5) When the liquid cooling cabinet is in the static stage, if the battery cell temperature is appropriate, the water-air heat exchange circuit 20 on the PCS side is in the standby mode, and the compressor refrigeration circuit 10 on the battery side is in the standby mode;

[0104] The above action logic can effectively reduce the action time of the loops on both sides of the dual-circulation chiller, and achieve complete decoupling of the battery side and the PCS side.

[0105] Take a certain capacity energy storage liquid cooling integrated cabinet as an example, equipped with a dual-circuit chiller, the energy storage liquid chiller operates at 0.5C charge and discharge, and according to the typical operating conditions of charge-rest-discharge-rest, the complete charge and discharge cycle time is about 5 hours. The chiller operating status under this typical charge and discharge operating condition is shown in the following table:

[0106] Charge and discharge operation status Battery side compressor refrigeration circuit operating status Operation status of water-to-air heat exchange circuit on PCS side Early stage of charging (battery cell temperature is appropriate) Standby mode Operation Mode Mid to late charging period (cell temperature exceeds limit) Cooling mode Operation Mode Standstill (battery cell temperature exceeds limit) Cooling mode Standby mode Early stage of discharge (battery core temperature is appropriate) Standby mode Operation Mode Mid to late stage of discharge (cell temperature exceeds limit) Cooling mode Operation Mode Standstill (battery cell temperature exceeds limit) Cooling mode Standby mode

[0107] ① The initial stage of charging when the battery cell temperature is appropriate: Since the battery cell temperature is appropriate and the battery specific heat is large, the temperature rise rate is slow, and the battery side compressor refrigeration circuit 10 does not operate; since the PCS side has a large power after charging and discharging, the PCS side water-air heat exchange circuit 20 executes the operation mode, the PCS side water pump 201 starts to perform cooling cycle, and the heat exchange fan 60 performs corresponding actions according to the target water temperature and the fan start-stop setting value to ensure that the liquid supply temperature on the PCS side meets the requirements. Since the battery cell has a large specific heat and the temperature rises slowly, the battery side compressor refrigeration circuit 10 does not operate for about 40 minutes during the entire initial charging period, that is, only the PCS side water-air heat exchange circuit operates in the first 40 minutes of charging, and only the PCS side water pump 201 and heat exchange fan 60 operate in the PCS side water-air heat exchange circuit 20, the maximum power consumption is less than 450W, and the overall power consumption is in the range of 150W~450W. Compared with conventional chillers, the power consumption is reduced by more than 70%.

[0108] ② In the middle and late stages of charging, when the battery cell temperature exceeds the limit, the battery side compressor refrigeration circuit 10 starts to operate, and the compressor 111 in the battery side refrigeration circuit is adjusted by frequency conversion control to always provide a constant temperature cold source of 18°C ​​to effectively cool the battery cell. At the same time, the frequency conversion adjustment compressor can accurately match the thermal load demand of the battery pack without causing waste of cooling capacity. The PCS side water-to-air heat exchange circuit 20 continues to maintain the original control mode. The process lasts for about 80 minutes.

[0109] ③ After charging, the energy storage liquid refrigerator is in the static cooling stage: Since there is no power on the PCS side, the water-air heat exchange circuit on the PCS side switches from the operating mode to the standby mode after charging. Since the overall temperature level of the battery cell is high after charging, the battery side compressor refrigeration circuit 10 continues to maintain the refrigeration mode and provides a constant temperature cold source of 18°C. After charging, the static cooling process lasts for about 30 minutes. Since the PCS side circuit does not work, only the battery side circuit works. The overall operating power consumption in this stage decreases by about 10%.

[0110] ④ The initial stage of discharge when the battery cell temperature is appropriate: The energy-saving control strategy, duration and energy-saving effect of the chiller at this stage can refer to ① The initial stage of charging when the battery cell temperature is appropriate.

[0111] ⑤ The stage where the battery cell temperature exceeds the limit in the middle and late stages of discharge: The energy-saving control strategy, duration and energy-saving effect of the chiller in this stage can refer to ② The stage where the battery cell temperature is appropriate in the middle and late stages of charging.

[0112] ⑥ The energy storage liquid refrigerator is left to cool down after discharge: The energy-saving control strategy, duration and energy-saving effect of the chiller in this stage can refer to ③ The energy storage liquid refrigerator is left to cool down after charging.

[0113] For a complete charge and discharge cycle, the overall operation time of the battery side compressor refrigeration circuit is about 220 minutes, and the operation time of the PCS side water-air heat exchange circuit is about 240 minutes. However, with the conventional chiller cooling solution, both loops need to maintain the operation state throughout the complete charge and discharge cycle, and the overall operation time reaches 300 minutes. Compared with the conventional chiller thermal management control solution, the dual-circuit chiller thermal management energy-saving and efficient control solution can effectively shorten the chiller operation time.

[0114] Example 3

[0115] The present invention is applicable to thermal management control action logic examples under different environmental conditions, and the specific implementation steps are as follows:

[0116] like Figure 3 , 4 , 6, and 7, the operation modes of the two-side loops are adjusted for different ambient temperatures. Specifically, when the dual-circuit energy storage chiller is in an ambient temperature of -5~45°C, the battery-side compressor refrigeration loop 10 and the PCS-side water-air heat exchange loop 20 operate independently. At this time, the electric two-way valve 40 and the electric three-way valve 50 provided between the battery-side compressor refrigeration loop 10 and the PCS-side water-air heat exchange loop 20 are both kept closed;

[0117] When the dual-circulation loop energy storage chiller is in a low ambient temperature condition below -5°C and a high ambient temperature condition above 45°C, the battery side compressor refrigeration circuit 10 and the PCS side water-to-air heat exchange circuit 20 operate in parallel. At this time, the electric two-way valve 40 and the electric three-way valve 50 are both kept open.

[0118] In step S1, if the ambient temperature is greater than 45°C and the actual liquid supply temperature T pcs More than T pcs_max The water-air heat exchange circuit 20 on the PCS side maintains the running mode. At this time, the high-temperature mixed water mode is triggered, that is, the battery-side compressor refrigeration circuit 10 switches to the refrigeration mode, and the low-temperature coolant of the liquid-cooled battery pack flows into the water-air heat exchange circuit 20 on the PCS side and mixes with the high-temperature fluid of the liquid-cooled PCS. The liquid supply temperature of the water-air heat exchange circuit 20 on the PCS side is reduced by mixing the low-temperature cold source, so that it always provides the liquid-cooled PCS with a cold source whose liquid temperature meets the set requirements.

[0119] If the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit 10 is in the cooling mode, and the low-temperature mixed water mode is triggered. That is, the electric two-way valve 40 between the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 is in a fully open state, and the electric three-way valve 50 is half-opened, so that the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit 20.

[0120] In step S2, if the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit 10 is in the cooling mode, and the low-temperature mixed water mode is triggered, that is, the PCS side water-air heat exchange circuit 20 is switched to the operation mode, and the electric two-way valve 40 arranged between the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 is in a fully open state, and the electric three-way valve 50 is opened half-open, so that the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit 20.

[0121] It should be noted that the ambient temperature ranges given in the present invention are all typical values, and the actual ambient temperature operating range may be different, that is, the ambient temperature range may be variable according to different system cooling capacity configurations.

[0122] In addition, the opening ranges of the electric valves given in the present invention are all typical values, and the actual openings of the electric valves may be different, that is, according to different liquid cooling cabinet capacity configurations, different charge and discharge ratios, and different electric valve structures, the actual opening range of the electric valves can be variable. For example, the small opening of the electric three-way valve under high-temperature mixed water can be any opening in the range of 0 to 180°, and the electric two-way valve can be fully opened at a certain opening of 0 to 180°; the half opening of the electric three-way valve under low-temperature mixed water can be any opening in the range of 0 to 180°, and the electric two-way valve can be fully opened at any opening in the range of 0 to 180°.

[0123] Of course, the water mixing unit composed of the electric three-way valve, the electric two-way valve and the corresponding branches described in Example 1 of the present invention is only one form, and there are many other structural forms.

[0124] For example, Figure 8 As shown, the branch FG where the electric two-way valve 40 is located and the pressure stabilizing system 30 constitute another structural form of a pressure stabilizing unit. The pressure stabilizing system 30 is composed of a single airbag expansion tank 300, which is connected to the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20 respectively. There is a liquid level difference between the battery side compressor refrigeration circuit 10 and the PCS side water-air heat exchange circuit 20, which facilitates the flow of water.

[0125] When the two circuits operate independently, the electric two-way valve 40 is in a closed state, and water cannot flow through the branch where the voltage stabilizing system is located, and the two circuits are completely isolated; when the two circuits operate in parallel, the electric two-way valve 40 is opened at any angle, and the cold water of the battery-side compressor refrigeration circuit 10 will flow from the FG branch into the PCS-side water-to-air heat exchange circuit 20, and after mixing, the hot water will return from the PCS-side water-to-air heat exchange circuit 20 to the battery-side compressor refrigeration circuit 10 by the voltage stabilizing system, completing the water mixing cycle.

[0126] It should be noted that the two cases shown in the present invention only demonstrate the specific operation form of the water mixing unit with two circuits running in parallel. There are still a variety of structural forms that can realize the above functions, and similar structures all fall within the scope of protection of this patent.

[0127] Of course, the pressure stabilizing system composed of the expansion tank and the branch circuit described in Example 1 of the present invention is only one form, and there are many structural forms of the pressure stabilizing system.

[0128] For example, separate expansion tanks are provided for pressure stabilization in the battery-side compressor refrigeration circuit and the PCS-side water-to-air heat exchange circuit, so that the same back pressure or different back pressure can be achieved in the two circuits; for example, a high-level water tank structure can still be used to achieve the same pressure stabilization effect.

[0129] It should be noted that the case shown in the present invention only demonstrates the specific operation form of two-circuit voltage stabilization. There are still many structural forms that can realize the above functions, and similar structures all fall within the scope of protection of this patent.

[0130] Of course, the arrangement positions of the condenser and the water-to-air heat exchange core described in Example 1 of the present invention can be stacked or arranged up and down on the same plane. In the case of stacked arrangement, the condenser and the water-to-air heat exchange core can be arranged in front or behind to meet the needs. In the case of up and down arrangement, the condenser and the water-to-air heat exchange core can be arranged in the top or bottom to meet the needs. Similar structures all fall within the scope of protection of this patent.

[0131] The design advantages of the present invention are:

[0132] 1) System configuration innovation: The present invention provides a new chiller technology route. The dual-circuit chiller is equipped with a battery-side compressor refrigeration circuit and a PCS-side water-to-air heat exchange circuit to meet the cooling needs of the battery side and the PCS side, respectively, to achieve thermal management decoupling of the battery side and the PCS side. The PCS-side water-to-air heat exchange circuit adopts forced natural convection heat exchange, which saves more than 70% energy compared to the fluorine cooling solution. The battery-side compressor refrigeration circuit can choose a fluorine cooling configuration solution with smaller cooling demand and lower energy consumption, to achieve high efficiency and energy saving.

[0133] 2) Innovation of energy-saving control scheme: The present invention provides an energy-saving control scheme for a dual-circuit energy storage chiller. The chiller can receive and execute action instructions and related fixed values ​​issued by the BMS in real time to achieve efficient energy-saving control. The energy-saving control scheme provided by the present invention should reduce the overall action time of the battery side water circuit by about 20% and the overall action time of the PCS side water circuit by about 20% for typical charge and discharge operating conditions (0.5C full charge and discharge + static cooling).

[0134] In summary, the present invention relies on the dual-circuit chiller system configuration innovation and energy-saving control scheme to achieve complete decoupling of the battery side refrigeration circuit and the PCS side refrigeration circuit. According to the cooling requirements of the battery pack and PCS, the two circuits can act independently, reducing the chiller action time, avoiding the waste of cooling capacity, and greatly reducing the comprehensive energy consumption of the energy storage liquid refrigerator system. Combined with the actual charging and discharging operating conditions, the comprehensive energy consumption is reduced by 40%.

[0135] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A double-circuit energy storage chiller, characterized in that: It includes a battery side compressor refrigeration circuit (10) and a PCS side water-air heat exchange circuit (20) which can be operated independently or in parallel. The battery side compressor refrigeration circuit (10) is connected to the liquid-cooled battery pack cold plate to form a circulation circuit, which is used to always provide constant temperature cooling water for the liquid-cooled battery pack. The battery-side compressor refrigeration circuit (10) comprises a battery-side cooling circulation system (100) and a refrigeration circulation system (110), wherein the battery-side cooling circulation system (100) and the refrigeration circulation system (110) perform heat exchange with an evaporator (120) to achieve refrigeration. The PCS side water-air heat exchange circuit (20) is connected to the PCS cold plate to form a circulation circuit, and always uses the forced convection heat exchange principle to realize water-air heat exchange, which is used to cool the liquid-cooled energy storage converter PCS. The battery side compressor refrigeration circuit (10) and the PCS side water-to-air heat exchange circuit (20) share the same set of heat exchange fans (60) for water-to-air heat exchange core heat exchange. The battery side compressor refrigeration circuit (10) and the PCS side water-to-air heat exchange circuit (20) share a set of pressure stabilization systems (30) to achieve circuit buffering and pressure stabilization. The pressure stabilization system (30) includes an expansion tank (300). The pressure stabilization port of the expansion tank (300) is simultaneously connected to the battery side cold cycle circuit (100) and the PCS side water-to-air heat exchange circuit (20) to ensure that both sides have the same system back pressure. Two branch circuits with different structures are provided between the battery-side cold-load circulation system (100) and the PCS-side water-air heat exchange circuit (20), i.e., an electric two-way valve (40) and an electric three-way valve (50) are provided on the branch circuit, and the two sides can be operated independently or in parallel by virtue of different actions of the electric two-way valve (40) and the electric three-way valve (50). When the electric two-way valve (40) and the electric three-way valve (50) are in a closed state, the circuits on both sides can be operated independently; when the electric two-way valve (40) and the electric three-way valve (50) are in an open state, the circuits on both sides can be operated in parallel. Alternatively, an electric two-way valve is provided on the branch circuit, and the branch circuit FG where the electric two-way valve is located and the pressure stabilizing system (30) form another structural form of a pressure stabilizing unit, wherein the pressure stabilizing system (30) is composed of a single airbag expansion tank (300) connected to the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20), respectively, and there is a liquid level difference between the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20), which facilitates the flow of water. When the two circuits are operated independently, the electric two-way valve is in a closed state, and water cannot flow through the branch where the voltage stabilizing system is located, and the two circuits are completely isolated. When the two circuits are operated in parallel, the electric two-way valve is opened at any angle, and the cold water of the battery side compressor refrigeration circuit (10) flows from the FG branch into the PCS side water-to-air heat exchange circuit (20). After mixing, the hot water is returned from the PCS side water-to-air heat exchange circuit (20) to the battery side compressor refrigeration circuit (10) by the voltage stabilizing system, completing the water mixing cycle.

2. The double-circuit energy storage chiller according to claim 1, characterized in that: The battery side cooling circulation system (100) comprises a battery side water pump (101) and a heater (102); the inlet of the battery side water pump (101) is connected to the outlet pipeline of the liquid-cooled battery pack cold plate, and a first temperature sensor (103) and a first pressure sensor (104) for monitoring the return temperature and pressure of cooling water in the pipe are provided near the inlet of the pipeline; the outlet of the battery side water pump (101) flows into the second valve port through the first valve port of the electric three-way valve (50) and is connected to the inlet end of the heater (102); the outlet end of the heater (102) is connected to the first inlet end of the evaporator (120); the third valve port of the electric three-way valve (50) is connected to the PCS side water-air heat exchange circuit (20); the first outlet pipeline of the evaporator (120) is connected to the inlet pipeline of the liquid-cooled battery pack cold plate, and a second temperature sensor (105) and a second pressure sensor (106) for monitoring the supply temperature and pressure of cooling water in the pipe are provided on the pipeline.

3. The double-circulation loop energy storage chiller according to claim 1, characterized in that: The refrigeration cycle system (110) comprises a compressor (111), a throttling device (112), a filter dryer (113) and a condenser (114); the second outlet of the evaporator (120) is connected to the inlet of the condenser (114) through the compressor (111); the outlet of the condenser (114) is connected to the second inlet pipeline of the evaporator (120), and the filter dryer (113) and the throttling device (112) are connected in series on the pipeline.

4. The double-circulation loop energy storage chiller according to claim 1, characterized in that: The PCS-side water-to-air heat exchange circuit (20) comprises a PCS-side water pump (201) and a water-to-air heat exchanger core (202); the water inlet of the PCS-side water pump (201) is connected to the outlet pipeline of the PCS cold plate, and a third temperature sensor (203) for monitoring the return liquid temperature of cooling water in the pipe is provided on the pipeline; the water outlet of the PCS-side water pump (201) is connected to the inlet pipeline of the PCS cold plate through the water-to-air heat exchanger core (202), and a fourth temperature sensor (204) and a third pressure sensor (205) for monitoring the supply liquid temperature and pressure of cooling water in the pipe are provided on the pipeline; an ambient temperature sensor (206) is also provided at the air inlet position of the water-to-air heat exchanger core (202) for monitoring the air inlet temperature.

5. The double-circulation loop energy storage chiller according to claim 1, characterized in that: A liquid injection and discharge port (303) is provided in the pipeline of the battery-side cooling circulation system (100).

6. A thermal management control method for a dual-circulation energy storage chiller according to claim 1, characterized in that: It includes a dual-circulation energy storage chiller, and serves as the core thermal management control system in the energy storage liquid cooling integrated cabinet, which is used to control the battery cell temperature and the IGBT temperature in the PCS in real time under any working conditions. The dual-circulation energy storage chiller is issued action instructions and working modes in real time by the battery energy management system BMS. At the same time, the battery energy management system BMS pre-sets the battery cell temperature for starting cooling of the liquid-cooled battery pack to T BAT_COOL , the cell temperature T of the liquid-cooled battery pack when starting heating BAT_HEAT , Liquid-cooled battery pack has large temperature difference between cells and starts in self-circulation mode. BAT_DIF , and the upper limit temperature of the liquid supply of the liquid-cooled PCS T pcs_max , the specific thermal management steps are as follows: Step S1: When the energy storage liquid cooling integrated cabinet is in the charging and discharging stage, Step S11: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The water-air heat exchange circuit (20) on the PCS side is in the operation mode, and the compressor refrigeration circuit (10) on the battery side is in the standby mode. Step S12: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , the water-air heat exchange circuit (20) on the PCS side is in the operating mode, and the compressor refrigeration circuit (10) on the battery side is in the cooling mode. Step S13: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , the water-air heat exchange circuit (20) on the PCS side is in the operation mode, and the compressor refrigeration circuit (10) on the battery side is in the heating mode. Step S2: When the energy storage liquid cooling integrated cabinet is in the static stage, Step S21: If the battery cell temperature is over-temperature and its actual temperature is ≥T BAT_COOL , the water-air heat exchange circuit (20) on the PCS side is in the standby mode, and the compressor refrigeration circuit (10) on the battery side is in the refrigeration mode. Step S22: If the cell temperature is too low and its actual temperature is ≤T BAT_HEAT , the water-air heat exchange circuit (20) on the PCS side is in standby mode, and the compressor refrigeration circuit (10) on the battery side is in heating mode. Step S23: If the actual temperature of the battery cell is between T BAT_COOL and T BAT_HEAT The water-air heat exchange circuit (20) on the PCS side is in a standby mode, and the compressor refrigeration circuit (10) on the battery side is in a standby mode.

7. The thermal management control method for a dual-circulation energy storage chiller according to claim 6, characterized in that: When the battery side compressor refrigeration circuit (10) is in standby mode, all components of the battery side compressor refrigeration circuit (10) are not in operation; When the battery side compressor refrigeration circuit (10) is in the refrigeration mode, the battery side water pump (101) in the circuit operates, the compressor (111) and the heat exchange fan (60) automatically adjust the operating frequency according to the target temperature, and the throttling device (112) automatically adjusts the valve opening according to the refrigerant pressure to match the required heat load. When the battery side compressor refrigeration circuit (10) is in the heating mode, the battery side water pump (101) is running, and the heater (102) in the battery side cold cycle system (100) determines whether to execute the heating command based on the real-time battery side liquid supply temperature collected by the second temperature sensor (105) on the battery side and the heater start-stop setting value. When the battery-side compressor refrigeration circuit (10) is in a self-circulation mode, only the battery-side water pump (101) operates, and the other components do not operate.

8. The thermal management control method for a dual-circulation energy storage chiller according to claim 6, characterized in that: When the PCS-side water-air heat exchange circuit (20) is in standby mode, and the PCS-side water pump (201) is in standby mode, When the PCS side water-air heat exchange circuit (20) is in operation mode, and the PCS side water pump (201) it has is in operation, and based on the PCS side supply liquid temperature collected in real time by the fourth temperature sensor (204), the PCS side supply liquid temperature is matched to the target water temperature through the heat exchange fan (60) by frequency conversion regulation.

9. The thermal management control method for a dual-circulation energy storage chiller according to claim 6, characterized in that: When the dual-circuit energy storage chiller is in an ambient temperature of -5 to 45°C, the battery-side compressor refrigeration circuit (10) and the PCS-side water-air heat exchange circuit (20) operate independently, and at this time, the electric two-way valve (40) and the electric three-way valve (50) provided between the battery-side compressor refrigeration circuit (10) and the PCS-side water-air heat exchange circuit (20) are both kept in a closed state; When the dual-circulation loop energy storage chiller is in a low ambient temperature condition below -5°C or a high ambient temperature condition above 45°C, the battery side compressor refrigeration circuit (10) and the PCS side water-to-air heat exchange circuit (20) operate in parallel. At this time, the electric two-way valve (40) and the electric three-way valve (50) are both kept in an open state to perform a water mixing operation.

10. The thermal management control method for a dual-circulation energy storage chiller according to claim 6, characterized in that: In step S1, if the ambient temperature is greater than 45°C and the actual liquid supply temperature T pcs More than T pcs_max The PCS side water-air heat exchange circuit (20) maintains the running mode state. At this time, the high-temperature mixed water mode is triggered, that is, the battery side compressor refrigeration circuit (10) switches to the refrigeration mode, and the low-temperature coolant of the liquid-cooled battery pack flows into the PCS side water-air heat exchange circuit (20) and mixes with the high-temperature fluid of the liquid-cooled PCS. The liquid supply temperature of the PCS side water-air heat exchange circuit (20) is reduced by mixing the low-temperature cold source, so that it always provides the liquid-cooled PCS with a cold source whose liquid temperature meets the set requirements. If the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit (10) is in the refrigeration mode, and the low-temperature water mixing mode is triggered at this time, that is, the electric two-way valve (40) arranged between the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20) is in a fully open state, and the electric three-way valve (50) is opened halfway, so that the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20) are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit (20).

11. The thermal management control method for a dual-circulation energy storage chiller according to claim 6, characterized in that: In step S2, if the ambient temperature is less than -5°C, the battery side compressor refrigeration circuit (10) is in the refrigeration mode, and the low temperature water mixing mode is triggered at this time, that is, the PCS side water-air heat exchange circuit (20) is switched to the operation mode, and the electric two-way valve (40) provided between the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20) is in a fully open state, and the electric three-way valve (50) is opened halfway, so that the battery side compressor refrigeration circuit (10) and the PCS side water-air heat exchange circuit (20) are mixed, and the liquid-cooled PCS and the liquid-cooled battery pack share the natural cooling function of the PCS side water-air heat exchange circuit (20).

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