Direct cooling and heating management system, energy storage container and control method

Abstract

The invention provides a direct cooling and heating management system, an energy storage container and a control method, and the direct cooling and heating management system is used for carrying out heat exchange on a plurality of batteries in an energy storage system and comprises a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger which are sequentially communicated to form a refrigerant loop. And in the heating mode, a refrigerant flowing out of the first heat exchange part of the third heat exchanger flows to the fourth heat exchange part of the first heat exchanger through the fourth branch, and the refrigerant flowing through the third heat exchange part of the first heat exchanger exchanges heat with the refrigerant flowing through the first heat exchange part, so that the refrigerant flowing into the fourth heat exchanger can be kept at the preset temperature. According to the direct cooling and heating management system, in the battery heating process, the first heat exchanger is used for conducting heat exchange on the refrigerant flowing out of the compressor, precise control and adjustment of the superheat degree of the refrigerant flowing to the fourth heat exchanger during heating are achieved, and the uniform temperature degree of a battery cell during heating is improved. And meanwhile, the battery cell can be defrosted without cooling during heating, and the heating effect is improved.

Description

Technical Field

[0001] The present application discloses the technical field of energy storage systems, and in particular, relates to a direct cooling thermal management system, an energy storage container, and a control method. Background Art

[0002] The cabinet-type energy storage system is an energy storage system designed and installed in the form of a cabinet. It integrates the energy storage system, inverter and other necessary components and control equipment to achieve the storage and conversion functions of electrical energy. With the increasing demand for energy storage, temperature control of the energy storage system is the key to ensure the normal operation of the system.

[0003] In the process of realizing the present invention, the inventors found that there are at least the following technical problems in the prior art: In the prior art, the temperature control of energy storage batteries generally adopts direct cooling, using refrigerant as a heat transfer medium, and completing the heat exchange of the energy storage battery through the flow and phase change of the refrigerant. However, in the process of heating the energy storage battery, the refrigerant flowing out of the compressor directly heats the energy storage battery, and the exhaust gas superheat is not processed, resulting in poor consistency and poor temperature uniformity of the refrigerant diversion entering multiple direct cooling cold plates, thereby affecting the heating effect of the direct cooling cold plates on the battery. Summary of the invention

[0004] In view of this, the present application provides a direct cooling heat management system, energy storage container and control method, which can process the refrigerant flowing out of the compressor during the heating process of the energy storage battery, and improve the temperature uniformity of the battery cells during the heating process. At the same time, it can realize the defrosting function of the battery cells without cooling down during the heating process, so as to effectively solve the problem that the battery cells cannot be defrosted at low temperatures.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, a direct cooling heat management system is provided for exchanging heat for a plurality of batteries in an energy storage system, comprising: a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger connected in sequence to form a refrigerant circuit;

[0007] The refrigerant circuit includes multiple branches, the second heat exchanger and the fourth heat exchanger are connected through a first branch, the fourth heat exchanger and the inlet side of the compressor are connected through a second branch, and the outlet side of the compressor is connected to a third branch;

[0008] The third heat exchanger includes a first heat exchange part and a second heat exchange part that exchanges heat with the first heat exchange part, the first heat exchange part is arranged on the first branch, and the second heat exchange part is arranged on the second branch, so that the refrigerant flowing out of the second heat exchanger exchanges heat with the refrigerant flowing out of the fourth heat exchanger, and the first heat exchange part is connected to the inlet side of the compressor through the fourth branch;

[0009] The first heat exchanger includes a third heat exchange part and a fourth heat exchange part for exchanging heat with the third heat exchange part, the third heat exchange part is arranged on the third branch, and the fourth heat exchange part is arranged on the fourth branch;

[0010] Among them, in the heating mode, the refrigerant flowing out of the first heat exchange part flows to the fourth heat exchange part through the fourth branch, and the refrigerant flowing through the third heat exchange part exchanges heat with the refrigerant after throttling through the first heat exchange part, so that the refrigerant flowing into the fourth heat exchanger can be maintained at a preset exhaust superheat.

[0011] In a feasible implementation, a first electronic expansion valve is provided on the fourth branch, and the first electronic expansion valve can control the opening degree of the fourth branch.

[0012] In a feasible implementation, the present invention further includes:

[0013] A first temperature detection unit is located at the outlet side of the third heat exchange part on the third branch;

[0014] A first pressure detection unit, located at the outlet side of the compressor;

[0015] A controller is used to control the first electronic expansion valve according to the collected values ​​of the first temperature detection unit and the first pressure detection unit in a heating mode.

[0016] In a feasible implementation, the direct cooling thermal management system has a defrost mode. In the defrost mode, the refrigerant flowing out of the compressor flows to the second heat exchanger through the third heat exchange part, and the refrigerant flowing out of the second heat exchanger flows to the compressor through the first heat exchange part, the fourth heat exchange part and the second heat exchange part.

[0017] In a feasible implementation, the present invention further includes:

[0018] A second temperature detection unit is located at the inlet side of the compressor;

[0019] A second pressure detection unit is located at the inlet side of the compressor;

[0020] A controller is provided for controlling the first electronic expansion valve according to the collected values ​​of the second temperature detection unit and the second pressure detection unit in a defrosting mode.

[0021] In a feasible implementation, a heater is provided on the air inlet side of the second heat exchanger.

[0022] In a feasible implementation, the first branch includes:

[0023] a first branch road, connected to the second heat exchanger and the fourth heat exchanger, the refrigerant circuit includes a first one-way valve and a second electronic expansion valve arranged on the first branch road, and the first one-way valve only allows the refrigerant to flow from the second heat exchanger to the fourth heat exchanger, and the first heat exchange part is located in the first branch road;

[0024] a second branch road, arranged in parallel with the first branch road, and communicating with the second heat exchanger and the first heat exchange part, the refrigerant circuit comprising a third electronic expansion valve arranged on the second branch road, the fourth branch road being connected to the second branch road, and the connection position of the fourth branch road and the second branch road being located at the inlet side of the third electronic expansion valve;

[0025] The third branch is arranged in parallel with the first branch and connects the fourth heat exchanger and the first heat exchange part. The refrigerant circuit includes a second one-way valve arranged on the third branch, and the second one-way valve only allows the refrigerant to flow from the fourth heat exchanger to the second heat exchanger.

[0026] In a feasible implementation, the second branch includes:

[0027] a fourth branch line, communicating with the multi-way valve and the fourth heat exchanger;

[0028] The fifth branch is arranged in series with the fourth branch and communicates with the multi-way valve and the compressor inlet. The second heat exchange part is located on the fifth branch.

[0029] In a feasible implementation, the multi-way valve includes a first interface connected to the first heat exchanger, a second interface connected to the second heat exchanger, a third interface connected to the compressor inlet, and a fourth interface connected to the fourth heat exchanger.

[0030] In a second aspect, an energy storage container is provided, comprising the direct cooling thermal management system described in any one of the above items.

[0031] In a third aspect, a control method for a thermal management system is provided, which is suitable for any of the thermal management systems described above, comprising the following steps:

[0032] In heating mode:

[0033] Control the first interface and the fourth interface of the multi-way valve to be connected, control the second interface and the third interface to be connected, control the first electronic expansion valve and the third electronic expansion valve to be opened, control the second electronic expansion valve to be closed, and control the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the fourth interface of the multi-way valve, the fourth heat exchanger, the first heat exchange part of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange part of the first heat exchanger in sequence, and merges with the refrigerant flowing out of the first heat exchange part of the third heat exchanger after passing through the third electronic expansion valve, the second heat exchanger, the second interface of the multi-way valve, and the third interface of the multi-way valve in sequence, and the merged refrigerant flows through the second heat exchange part of the third heat exchanger and flows back to the compressor;

[0034] In defrost mode:

[0035] Controlling the first interface and the second interface of the multi-way valve to be connected, controlling the first electronic expansion valve to be opened, controlling the second electronic expansion valve and the third electronic expansion valve to be closed, and controlling the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the second interface of the multi-way valve, the second heat exchanger, the first heat exchange part of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange part of the first heat exchanger, the second heat exchange part of the third heat exchanger in sequence and flows back to the compressor;

[0036] In cooling mode:

[0037] Control the first interface and the second interface of the multi-way valve to be connected, control the third interface and the fourth interface to be connected, control the second electronic expansion valve to open, control the first electronic expansion valve and the third electronic expansion valve to close, and control the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the second interface of the multi-way valve, the second heat exchanger, the first heat exchange part of the third heat exchanger, the second electronic expansion valve, the fourth heat exchanger, the fourth interface of the multi-way valve, the third interface of the multi-way valve, the second heat exchange part of the third heat exchanger and flows back to the compressor.

[0038] The direct cooling thermal management system provided by the present application has at least the following beneficial effects:

[0039] During the battery heating process, the first heat exchanger is used to heat the refrigerant flowing out of the compressor, so as to achieve precise control and adjustment of the superheat of the refrigerant flowing to the fourth heat exchanger during heating, and improve the temperature uniformity of the battery cells during heating. At the same time, in the middle of heating, by controlling the flow direction of the refrigerant, the refrigerant flowing out of the compressor can flow to the second heat exchanger through the first heat exchanger, and the refrigerant does not flow through the fourth heat exchanger. While the refrigerant flowing out of the compressor defrosts the second heat exchanger, the refrigerant does not absorb heat from the battery cells through the fourth heat exchanger, thereby achieving the defrosting function of the battery cells without cooling down during heating, solving the problem of the battery cells being unable to defrost at low temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0041] Figure 1 It is a schematic diagram of the connection structure of the thermal management system;

[0042] Figure 2 This is a schematic diagram of the refrigerant flow in heating mode;

[0043] Figure 3 This is a schematic diagram of the refrigerant flow in defrost mode;

[0044] Figure 4 This is a schematic diagram of the refrigerant flow in heating mode.

[0045] Figure numerals: 1. compressor; 2. first heat exchanger; 3. second heat exchanger; 4. third heat exchanger; 5. fourth heat exchanger; 6. first branch; 601. first branch; 602. second branch; 603. third branch; 7. second branch; 701. fourth branch; 702. fifth branch; 8. third branch; 9. fourth branch; 10. first electronic expansion valve; 11. first temperature detection unit; 12. first pressure detection unit; 13. second temperature detection unit; 14. second pressure detection unit; 15. heater; 16. first one-way valve; 17. second electronic expansion valve; 18. third electronic expansion valve; 19. second one-way valve; 20. multi-way valve; 21. gas-liquid separator; 22. filter. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] Reference Figure 1-Figure 4 The embodiment of the present application provides a direct cooling thermal management system for exchanging heat for multiple batteries in an energy storage system, including: a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, and a fourth heat exchanger 5 which are sequentially connected to form a refrigerant circuit, and a high-temperature and high-pressure gaseous refrigerant is provided at the compressor outlet, and by controlling the flow direction of the high-temperature and high-pressure gaseous refrigerant in the refrigerant circuit, the refrigerant in the fourth heat exchanger 5 is used to directly exchange heat with the battery in different modes, thereby achieving temperature transfer between the refrigerant in the fourth heat exchanger 5 and the battery.

[0048] The refrigerant circuit includes multiple branches, and the multiple branches are used to connect the various components. Among them, the second heat exchanger 3 and the fourth heat exchanger 5 are connected through the first branch 6, the fourth heat exchanger 5 and the inlet side of the compressor 1 are connected through the second branch 7, and the third branch 8 is connected to the outlet side of the compressor 1, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor outlet can cooperate through the third branch 8, the first branch 6 and the second branch 7 to realize the refrigerant heating mode cycle, defrosting mode cycle or cooling mode cycle.

[0049] The third heat exchanger 4 includes a first heat exchange part and a second heat exchange part that exchanges heat with the first heat exchange part. The first heat exchange part is arranged in the first branch 6 and is used as a heat release part. The second heat exchange part is arranged in the second branch 7 and is used as a heat absorption part, so that the refrigerant flowing out of the second heat exchanger 3 exchanges heat with the refrigerant flowing out of the fourth heat exchanger 5. The refrigerant entering the first heat exchange part exchanges heat with the refrigerant in the second heat exchange part, so that the subcooling degree of the liquid refrigerant flowing out of the first heat exchange part is increased, and the dryness of the refrigerant flowing to the fourth heat exchanger 5 after throttling is greatly reduced. In the cooling mode, if the refrigerant that has not been heat exchanged in the third heat exchanger 4 flows directly to the fourth heat exchanger 5 after throttling, the dryness of the refrigerant is relatively large, and it is difficult to control the uniform distribution when distributing the refrigerant to the cold plate in the subsequent pipeline. There is a problem of uneven distribution flow of the terminal PACK, which makes it impossible for the fourth heat exchangers 5 to achieve consistent flow distribution and uniform temperature requirements. The refrigerant that has been heat exchanged in the third heat exchanger 4 has a greatly reduced two-phase dryness after throttling due to the increase in supercooling, which greatly reduces the difficulty of flow distribution, can achieve a considerable degree of uniform distribution, and ensure the consistency of flow distribution of the fourth heat exchangers 5. In addition, the heat exchange between the second heat exchange part and the first heat exchange part can fully ensure that the refrigerant entering the second heat exchange part is a two-phase wet vapor with a dryness always less than 1, and also ensure that the entire heat exchange process in the cold plate is a two-phase state with a nearly constant temperature, thereby achieving the uniform temperature requirement between battery cells in a single PACK. In addition, the first heat exchange part distributes the flow uniformly to the multi-channel fourth heat exchanger 5, which can simultaneously meet the uniform temperature requirement of the battery cells in the PACK shown by the fourth heat exchanger 5 and the uniform temperature requirement of the average battery cell temperature between PACKs, thereby achieving the demand for direct heat exchange of the battery using the refrigerant.

[0050] Furthermore, the first heat exchange part and the inlet side of the compressor 1 are connected through the fourth branch 9, so that the refrigerant flowing out of the first heat exchange part can flow back to the compressor 1 through the fourth branch 9. The first heat exchanger 2 includes a third heat exchange part and a fourth heat exchange part that exchanges heat with the third heat exchange part, the third heat exchange part is arranged in the third branch 8, and the fourth heat exchange part is arranged in the fourth branch 9. In this way, in the heating mode, the refrigerant flowing out of the first heat exchange part flows to the fourth heat exchange part through the fourth branch 9, and the refrigerant flowing through the third heat exchange part exchanges heat with the refrigerant after throttling through the first heat exchange part, so that the refrigerant flowing into the fourth heat exchanger 5 can be maintained at a preset exhaust superheat. With the above arrangement, in the heating mode, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 passes through the first heat exchanger 2 for heat exchange and then flows to the fourth heat exchanger 5. The first heat exchanger 2 is used to exchange heat with the refrigerant flowing out of the compressor 1, so that the superheat of the refrigerant flowing to the fourth heat exchanger 5 can be accurately controlled and regulated during heating, thereby improving the temperature uniformity of the battery cells during heating.

[0051] Specifically, refer to Figure 2In the heating mode, after the refrigerant is compressed by the compressor 1, it becomes a high-temperature and high-pressure gaseous refrigerant and flows from the compressor outlet to the first heat exchanger 2. After the high-temperature and high-pressure gaseous refrigerant exchanges heat in the first heat exchanger 2, it flows to the fourth heat exchanger 5. The refrigerant in the fourth heat exchanger 5 directly exchanges heat with the battery to form a high-temperature and high-pressure liquid refrigerant. The formed high-temperature and high-pressure liquid refrigerant then flows to the first heat exchange part of the third heat exchanger 4, releases heat in the first heat exchange part, and flows out and is diverted. Part of the refrigerant, after being processed by the throttling device, flows through the second heat exchanger 3 to form a low-temperature and low-pressure two-phase wet vapor refrigerant that flows to the compressor inlet. In the process of flowing to the compressor inlet, the low-temperature and low-pressure refrigerant passes through the second heat exchange part of the third heat exchanger 4. The refrigerant in the second branch 7 exchanges heat with the liquid refrigerant in the first heat exchange part, so that the gaseous refrigerant entering the second heat exchange part absorbs heat, and then forms a low-temperature and low-pressure gaseous refrigerant that enters the compressor inlet. The remaining part of the refrigerant that flows out and is diverted after releasing heat in the first heat exchange part flows to the fourth heat exchange part of the first heat exchanger 2 through the fourth branch 9, absorbs heat after exchanging heat with the high-temperature and high-pressure gaseous refrigerant flowing out of the compressor 1 in the fourth heat exchange part, and then flows to the second heat exchange part of the third heat exchanger 4 to exchange heat with the liquid refrigerant in the first heat exchange part, so that the gaseous refrigerant entering the second heat exchange part absorbs heat, and then forms a low-temperature and low-pressure gaseous refrigerant that enters the compressor inlet, and after being compressed by the compressor 1, it becomes a high-temperature and high-pressure gaseous refrigerant that is discharged from the compressor outlet, thereby completing a heating cycle. In a specific embodiment, the refrigerant flowing out of the second heat exchanger 3 and the refrigerant flowing out of the fourth heat exchange part of the first heat exchanger 2 merge and enter the second heat exchange part of the third heat exchanger 4.

[0052] In the heating mode, the second heat exchange part of the third heat exchanger 4 exchanges heat with the first heat exchange part, which can fully ensure that the refrigerant entering the second heat exchange part is a two-phase wet vapor with a dryness always less than 1. The evaporation process in the second heat exchanger 3 has only two phases that are nearly constant temperature, which can effectively reduce the difference between the evaporation temperature and the ambient temperature, thereby eliminating the low evaporation temperature caused by the existence of superheat in the evaporator that absorbs heat from the environment, and increasing the system flow during heating to effectively increase the heating amount and improve the heating capacity.

[0053] The above-mentioned heat exchange between the refrigerant discharged from the first heat exchange part of the third heat exchanger 4 and the refrigerant discharged from the outlet of the compressor 1 can prevent the high-temperature and high-pressure gaseous refrigerant discharged from the outlet of the compressor 1 from directly entering the fourth heat exchanger 5 in a low-temperature environment, so that the superheat of the refrigerant is maintained at a preset superheat, thereby ensuring uniform temperature inside the battery cell during heating.

[0054] In cooling mode, refer to Figure 4, the fourth branch 9 is open, and the refrigerant is compressed by the compressor 1 and becomes a high-temperature and high-pressure gaseous refrigerant, which flows from the compressor outlet to the third heat exchange part of the first heat exchanger 2. After flowing through the third heat exchange part, the refrigerant flows to the second heat exchanger 3 to release heat, and the formed medium-temperature and high-pressure liquid refrigerant flows to the first heat exchange part of the third heat exchanger 4. After releasing heat in the first heat exchange part, the refrigerant flows directly to the fourth heat exchanger 5 through the first branch 6. After being processed by the throttling device, the refrigerant becomes a low-temperature and low-pressure liquid refrigerant and enters the fourth heat exchanger 5. The refrigerant in the fourth heat exchanger 5 directly exchanges heat with the battery to form a low-temperature, low-pressure wet vapor refrigerant with a dryness less than 1. During the process, the refrigerant in the second branch 7 passes through the second heat exchange part and exchanges heat with the liquid refrigerant in the first heat exchange part, so that the gaseous refrigerant entering the second heat exchange part absorbs heat, and then forms a low-temperature and low-pressure gaseous refrigerant that enters the compressor inlet. After being compressed by the compressor 1, it becomes a high-temperature and high-pressure gaseous refrigerant and is discharged from the compressor outlet, thereby completing a refrigeration cycle.

[0055] In the above process, the fourth branch 9 is controlled to be disconnected so that the first heat exchange part of the third heat exchanger 4 is disconnected from the fourth heat exchange part of the first heat exchanger 2. The third heat exchange part of the first heat exchanger 2 is only used as a flow path for the refrigerant and does not have the refrigerant heat exchange function, which makes it convenient to switch between the cooling mode and the heating mode and improves the system working efficiency.

[0056] It should be noted that the fourth heat exchanger 5 is a direct cooling cold plate that is in direct contact with the energy storage battery for heat exchange. At least one fourth heat exchanger 5 is provided, and each fourth heat exchanger 5 corresponds to an energy storage battery with heat exchange requirements. When multiple fourth heat exchangers 5 are provided, multiple fourth heat exchangers 5 are arranged in parallel, and the multiple fourth heat exchangers 5 are connected to the first branch 6 through a first stop valve, and the multiple fourth heat exchangers 5 are connected to the compressor inlet through a second stop valve.

[0057] In some embodiments, the first heat exchanger 2 and the third heat exchanger 4 are one of a shell and tube structure, a sleeve structure, and a plate structure. The structural form of the first heat exchanger 2 and the third heat exchanger 4 is selected according to actual needs. For example, the first heat exchanger 2 is a sleeve structure, the third heat exchange part is a first tube structure, the first tube structure is circulated with a refrigerant flowing in from the compressor 1, the fourth heat exchange part is a second tube structure arranged in the first tube structure, the second tube structure is circulated with a refrigerant flowing in from the fourth branch 9, and the refrigerants circulating in different positions are heat-transferred by the outer surface of the second tube structure. Of course, when the first heat exchanger 2 is a sleeve structure, the fourth heat exchange part can also be a first tube structure, the first tube structure is circulated with a refrigerant flowing in from the fourth branch 9, the third heat exchange part is a second tube structure arranged in the first tube structure, and the second tube structure is circulated with a refrigerant flowing in from the compressor 1.

[0058] In one possible implementation, referring to Figure 1 , the fourth branch 9 is provided with a first electronic expansion valve 10. The refrigerant flowing from the first heat exchange part of the third heat exchanger 4 to the fourth heat exchange part of the first heat exchanger 2 passes through the first electronic expansion valve 10 and arrives in the fourth heat exchange part. The first electronic expansion valve 10 can control the opening of the fourth branch 9, so that the first electronic expansion valve 10 can throttle and control the flow of the refrigerant flowing to the fourth heat exchange part. That is, in the heating mode, part of the refrigerant flowing out of the first heat exchange part enters the fourth branch 9, and is converted into a low-pressure and low-temperature two-phase refrigerant under the control of the first electronic expansion valve 10 and sent to the fourth heat exchange part. The first electronic expansion valve 10 indirectly controls the mass flow of the refrigerant entering the fourth heat exchange part by controlling the opening, so that the refrigerant flowing from the third heat exchange part to the fourth heat exchanger 5 in the heating mode can be maintained at the preset exhaust superheat, and in the defrosting mode, the fourth heat exchange part and the second heat exchange part become evaporators in the defrosting mode, so that there is no need to absorb heat from the battery cell during defrosting, and effective and rapid defrosting can still be achieved when the battery cell temperature is extremely low. The battery cells are evenly heated in heating mode, the battery cells do not cool down in defrosting mode, and the battery cells can still be defrosted normally and quickly when they are at extremely low temperatures.

[0059] In one possible implementation, referring to Figure 1 , further comprising a first temperature detection unit 11, a first pressure detection unit 12 and a controller, wherein the first temperature detection unit 11 is located at the outlet side of the third heat exchange part on the third branch 8, the first pressure detection unit 12 is located at the outlet side of the compressor 1, the first temperature detection unit 11 is preferably an exhaust temperature sensor, the exhaust temperature sensor is used to detect the real-time temperature of the refrigerant flowing out of the third heat exchange part, the first pressure detection unit 12 is preferably a high-pressure pressure sensor, the high-pressure pressure sensor is used to detect the refrigerant pressure flowing out of the compressor outlet, and convert the obtained refrigerant pressure into the refrigerant saturation temperature, and judge the refrigerant superheat by calculating the difference between the refrigerant real-time temperature and the refrigerant saturation temperature. In the heating mode, the controller controls the first electronic expansion valve 10 according to the collected values ​​of the first temperature detection unit 11 and the first pressure detection unit 12. In this way, in the heating mode, the opening of the first electronic expansion valve 10 is adaptively adjusted according to the refrigerant temperature obtained by the exhaust temperature sensor and the refrigerant pressure obtained by the high-pressure pressure sensor, thereby changing the refrigerant flow rate of the fourth branch 9 to the fourth heat exchange part, and then changing the heat exchange capacity of the first heat exchanger 2, ensuring that the refrigerant flowing out of the third heat exchange part is maintained within the preset superheat range.

[0060] Specifically, the exhaust temperature sensor and the high-pressure pressure sensor are communicatively connected with the controller, which receives the refrigerant temperature information and pressure information, and controls the opening of the first electronic expansion valve 10 according to the temperature information and pressure information, thereby realizing automatic control of the opening of the first electronic expansion valve 10, shortening the response time of the first electronic expansion valve 10, and precisely controlling the refrigerant flow rate so that the superheat of the refrigerant entering the fourth heat exchanger 5 is within the preset superheat, thereby improving the temperature uniformity of the battery cells during heating.

[0061] In an optional embodiment, the direct cooling heat management system has a defrost mode. In the defrost mode, the refrigerant flowing out of the compressor 1 flows to the second heat exchanger 3 through the third heat exchange part, and the refrigerant flowing out of the second heat exchanger 3 flows to the compressor 1 through the first heat exchange part, the fourth heat exchange part and the second heat exchange part. In this way, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 flows directly to the second heat exchanger 3 after heat exchange, and the refrigerant does not flow through the fourth heat exchanger 5. While ensuring the defrosting of the second heat exchanger 3, it does not absorb heat from the battery cell, so that the battery cell is defrosted without cooling down.

[0062] Specifically, refer to Figure 3 In the defrost mode, after the refrigerant is compressed by the compressor 1, it becomes a high-temperature and high-pressure gaseous refrigerant and flows from the compressor outlet to the first heat exchanger 2. After the high-temperature and high-pressure gaseous refrigerant exchanges heat in the first heat exchanger 2, it flows to the second heat exchanger 3, and after defrosting the second heat exchanger 3, it flows to the first heat exchange part of the third heat exchanger 4. After releasing heat in the first heat exchange part, it flows to the fourth heat exchange part of the first heat exchanger 2 through the fourth pipeline, and absorbs heat after exchanging heat with the high-temperature and high-pressure gaseous refrigerant flowing out of the compressor 1 in the fourth heat exchange part, and then flows to the second heat exchange part of the third heat exchanger 4 to exchange heat with the liquid refrigerant in the first heat exchange part, so that the gaseous refrigerant entering the second heat exchange part absorbs heat, and then forms a low-temperature and low-pressure gaseous refrigerant that enters the compressor inlet. After being compressed by the compressor 1, it becomes a high-temperature and high-pressure gaseous refrigerant and is discharged from the compressor outlet, thereby completing a defrost cycle.

[0063] The above-mentioned defrosting mode is applied to the process of heating the battery. During the process of heating the battery, due to the low ambient temperature, the second heat exchanger 3 has a frosting problem. Therefore, the first heat exchanger 2 and the third heat exchanger 4 are used to cooperate to realize the defrosting of the second heat exchanger 3, which can quickly restore the heat exchange efficiency of the second heat exchanger 3, thereby improving the performance of the entire system. In addition, when the second heat exchanger 3 is defrosted, the system does not need to set up an additional defrosting device by using the existing first heat exchanger 2 and the third heat exchanger 4, thereby optimizing the system structure and reducing the use cost. Preferably, a detection structure or detection device for judging whether the second heat exchanger 3 needs to be defrosted is set at the position of the second heat exchanger 3. If it is judged that the second heat exchanger 3 needs to be defrosted, by controlling the flow direction of the high-temperature and high-pressure gaseous refrigerant in the refrigerant circuit, the high-temperature and high-pressure gaseous refrigerant flowing out of the compressor 1 cannot enter the fourth heat exchanger 5, but flows through the second heat exchanger 3 and then flows back to the compressor 1, maintaining the battery temperature, and realizing the battery defrosting operation without cooling.

[0064] In one possible implementation, referring to Figure 1 , further comprising a second temperature detection unit 13, a second pressure detection unit 14 and a controller, both of which are located on the inlet side of the compressor 1. The second temperature detection unit 13 is preferably a return temperature temperature sensing sensor, which is used to detect the temperature of the refrigerant about to enter the compressor 1. The second pressure detection unit 14 is preferably a low-pressure pressure sensor, which is used to detect the pressure of the refrigerant about to enter the compressor 1. The controller controls the first electronic expansion valve 10 according to the collected values ​​of the second temperature detection unit 13 and the second pressure detection unit 14 in the defrost mode. In this way, in the defrost mode, according to the refrigerant temperature obtained by the return temperature temperature sensing sensor and the refrigerant pressure obtained by the low-pressure pressure sensor, the opening of the first electronic expansion valve 10 is adaptively adjusted to change the refrigerant flow rate of the fourth branch 9 to the fourth heat exchange part, thereby changing the heat exchange capacity of the first heat exchanger 2, so that the defrost function can operate normally.

[0065] The above-mentioned controller is connected in communication with the return temperature temperature sensor and the low-pressure pressure sensor. Preferably, the heating mode and the defrost mode share a controller, and in different modes, the controller can receive temperature information and pressure information sent by different components, and control the opening of the first electronic expansion valve 10 according to the temperature information and pressure information. Of course, two controllers can also be provided, for example, a first controller and a second controller, the first controller is connected in communication with the exhaust temperature sensor and the high-pressure pressure sensor, and the second controller is connected in communication with the return temperature sensor and the low-pressure pressure sensor, so as to ensure that in the heating mode and the defrost mode, the opening of the first electronic expansion valve 10 is controlled by different components to meet different usage requirements.

[0066] In one possible implementation, refer to Figure 1, a heater 15 is provided on the air inlet side of the second heat exchanger 3. The heater 15 is used to heat the air temperature entering the second heat exchanger 3. In this way, in the heating mode, when the external environment temperature is too low, causing the refrigerant temperature to be too low, which in turn leads to too little heating capacity, low heating efficiency, the system cannot operate normally or even loses the heating capacity, the heater 15 can be used to heat the air entering the second heat exchanger 3, increase the evaporation temperature, make the system operate normally, and increase the heating capacity.

[0067] In one possible implementation, referring to Figure 1 The first branch 6 includes a first branch 601, which connects the second heat exchanger 3 and the fourth heat exchanger 5. The refrigerant circuit includes a first one-way valve 16 and a second electronic expansion valve 17 arranged on the first branch 601, and the first one-way valve 16 only allows the refrigerant to flow from the second heat exchanger 3 to the fourth heat exchanger 5. The first heat exchange part is located in the first branch 601, that is, the third heat exchanger 4 is located between the second electronic expansion valve 17 and the first one-way valve 16.

[0068] The first branch 6 also includes a second branch 602, which is arranged in parallel with the first branch 601 and connects the second heat exchanger 3 and the first heat exchange part. The refrigerant circuit includes a third electronic expansion valve 18 arranged on the second branch 602. Both ends of the second branch 602 are connected to the first branch 601, one end of which is located between the second heat exchanger 3 and the first one-way valve 16, and the other end is located between the third heat exchanger 4 and the second electronic expansion valve 17. At the same time, the fourth branch 9 is connected to the second branch 602. Preferably, the connection position of the fourth branch 9 and the second branch 602 is located on the inlet side of the third electronic expansion valve 18. In this way, in the heating mode, the refrigerant flowing out of the first heat exchange part of the third heat exchanger 4 can be diverted into the fourth branch 9 before passing through the third electronic expansion valve 18, so that the first electronic expansion valve 10 on the fourth branch 9 can throttle and control the flow of the refrigerant in the fourth branch 9.

[0069] The first branch 6 also includes a third branch 603, which is arranged in parallel with the first branch 601 and connects the fourth heat exchanger 5 and the first heat exchange part. The refrigerant circuit includes a second one-way valve 19 arranged on the third branch 603, and the second one-way valve 19 only allows the refrigerant to flow from the fourth heat exchanger 5 to the second heat exchanger 3. One end of the third branch 603 is connected to the first branch 601, and the connection end is located between the first one-way valve 16 and the third heat exchanger 4.

[0070] In one possible implementation, referring to Figure 1, the second branch 7 includes a fourth branch 701 and a fifth branch 702, wherein the fourth branch 701 is used to connect the multi-way valve 20 and the fourth heat exchanger 5, the fifth branch 702 is arranged in series with the fourth branch 701, the fifth branch 702 is used to connect the multi-way valve 20 and the compressor inlet, the second heat exchange part is located at the fifth branch 702, and the connection point between the fourth branch 9 and the fifth branch 702 is located at the inlet side of the second heat exchange part of the third heat exchanger 4. In this way, in the heating mode, the refrigerant in the fourth branch 9 flows through the fourth heat exchange part of the first heat exchanger 2 and can merge with the refrigerant flowing to the compressor inlet of the second heat exchanger 3, and enter the second heat exchange part of the first heat exchanger 2 to absorb heat and then flow to the compressor inlet.

[0071] According to the above-mentioned setting, in the heating mode and the cooling mode, the refrigerant in the first heat exchange part and the refrigerant in the second heat exchange part are both reverse heat exchange, which can maximize the temperature difference of the refrigerant, improve the heat exchange efficiency, avoid insufficient heat exchange caused by too low or too high temperature cross point, and under the same heat transfer amount, the required heat transfer area is small, and the local heat transfer temperature difference of the refrigerant at any position of the heat transfer surface is relatively uniform. In the heating mode and the defrosting mode, the refrigerant in the third heat exchange part and the refrigerant in the fourth heat exchange part are also reverse heat exchange, which also has the effect of improving the heat exchange efficiency.

[0072] Furthermore, based on the above-mentioned embodiment, a filter 22 is arranged between the third heat exchanger 4 and the fourth heat exchanger 5. The filter 22 is arranged on the first branch road 601 and is preferably located between the second electronic expansion valve 17 and the third heat exchanger 4. The filter 22 is mainly used to remove impurities in the refrigerant to ensure the normal operation of the system.

[0073] In a feasible implementation, the multi-way valve 20 includes a first interface connected to the first heat exchanger 2 , a second interface connected to the second heat exchanger 3 , a third interface connected to the compressor inlet, and a fourth interface connected to the fourth heat exchanger 5 .

[0074] The multi-way valve 20 is used to realize different flow directions of the refrigerant in the refrigerant circuit in the heating mode, the defrosting mode, and the cooling mode. Specifically, in the heating mode, the first interface is connected to the fourth interface, and the second interface is connected to the third interface, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor outlet needs to pass through the first interface and the fourth interface before reaching the fourth heat exchanger 5, and the low-temperature and low-pressure wet steam refrigerant with a dryness less than 1 discharged from the second heat exchanger 3 passes through the second interface and the third interface, absorbs heat in the third heat exchanger 4 to become superheated gas, and then arrives at the compressor inlet, completing a heating cycle. In the cooling mode, the first interface is connected to the second interface, and the third interface is connected to the fourth interface, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor outlet needs to pass through the first interface and the second interface before reaching the second heat exchanger 3, and the low-temperature and low-pressure wet steam refrigerant with a dryness less than 1 discharged from the fourth heat exchanger 5 passes through the third interface and the fourth interface, absorbs heat in the third heat exchanger 4 to become superheated gas, and then arrives at the compressor inlet, completing a cooling cycle. In the defrost mode, the first interface is connected to the second interface, and the third interface is connected to the fourth interface, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor outlet needs to pass through the first interface and the second interface before reaching the second heat exchanger 3. A multi-way valve 20 is set to change the refrigerant flow direction, and the structure is simple and easy to operate.

[0075] Among them, the refrigerant circuit includes a gas-liquid separator 21. Before the refrigerant enters the compressor inlet, the gas-liquid separator 21 is used to separate the gaseous refrigerant and the liquid refrigerant in the refrigerant, and the separated liquid refrigerant is stored, so that the inlet of the compressor 1 only inhales the gaseous refrigerant, avoiding the liquid refrigerant entering the compressor 1 and causing liquid hammer. At the same time, the low-pressure pressure sensor and the return air temperature sensor are arranged between the compressor inlet and the gas-liquid separator 21. The low-pressure pressure sensor and the return air temperature sensor are respectively used to detect the pressure and temperature of the refrigerant entering the compressor 1, and feed back to the first electronic expansion valve 10 in real time in the defrost mode. By controlling the opening of the first electronic expansion valve 10, the pressure and temperature of the refrigerant entering the compressor 1 are kept in the optimal range.

[0076] In a second aspect, an energy storage container is provided. The energy storage container belongs to the field of energy storage and has a plurality of energy storage batteries. The above-mentioned direct cooling heat management system is used to perform direct cooling and heat exchange on the energy storage batteries to ensure the normal operation of the energy storage batteries.

[0077] In a third aspect, a control method for a thermal management system is provided, which is suitable for controlling the thermal management system, comprising the following steps:

[0078] In heating mode:

[0079] Control the first interface and the fourth interface of the multi-way valve 20 to be connected, control the second interface and the third interface to be connected, control the first electronic expansion valve 10 and the third electronic expansion valve 18 to be opened, control the second electronic expansion valve 17 to be closed, and control the compressor 1 to start, so that the refrigerant discharged from the compressor 1 flows through the third heat exchange part of the first heat exchanger 2, the first interface of the multi-way valve 20, the fourth interface of the multi-way valve 20, the fourth heat exchanger 5, the first heat exchange part of the third heat exchanger 4, the first electronic expansion valve 10, the fourth heat exchange part of the first heat exchanger 2 in sequence, and merges with the refrigerant flowing out of the first heat exchange part of the third heat exchanger 4 after passing through the third electronic expansion valve 18, the second heat exchanger 3, the second interface of the multi-way valve 20, and the third interface of the multi-way valve 20 in sequence, and the merged refrigerant flows through the second heat exchange part of the third heat exchanger 4 and flows back to the compressor 1.

[0080] In defrost mode:

[0081] The first interface and the second interface of the multi-way valve 20 are controlled to be connected, the first electronic expansion valve 10 is controlled to be opened, the second electronic expansion valve 17 and the third electronic expansion valve 18 are controlled to be closed, and the compressor 1 is controlled to start, so that the refrigerant discharged from the compressor 1 flows through the third heat exchange part of the first heat exchanger 2, the first interface of the multi-way valve 20, the second interface of the multi-way valve 20, the second heat exchanger 3, the first heat exchange part of the third heat exchanger 4, the first electronic expansion valve 10, the fourth heat exchange part of the first heat exchanger 2, the second heat exchange part of the third heat exchanger 4 and flows back to the compressor 1.

[0082] In cooling mode:

[0083] Control the first interface and the second interface of the multi-way valve 20 to be connected, control the third interface and the fourth interface to be connected, control the second electronic expansion valve 17 to be opened, control the first electronic expansion valve 10 and the third electronic expansion valve 18 to be closed, and control the compressor 1 to start, so that the refrigerant discharged from the compressor 1 flows through the third heat exchange part of the first heat exchanger 2, the first interface of the multi-way valve 20, the second interface of the multi-way valve 20, the second heat exchanger 3, the first heat exchange part of the third heat exchanger 4, the second electronic expansion valve 17, the fourth heat exchanger 5, the fourth interface of the multi-way valve 20, the third interface of the multi-way valve 20, the second heat exchange part of the third heat exchanger 4 and flows back to the compressor 1.

[0084] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0085] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A direct cooling thermal management system, characterized in that: Used to exchange heat for multiple batteries in an energy storage system, including: a compressor, a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger that are sequentially connected to form a refrigerant circuit; The refrigerant circuit includes multiple branches, the second heat exchanger and the fourth heat exchanger are connected through a first branch, the fourth heat exchanger and the inlet side of the compressor are connected through a second branch, and the outlet side of the compressor is connected to a third branch; The third heat exchanger includes a first heat exchange part and a second heat exchange part that exchanges heat with the first heat exchange part, the first heat exchange part is arranged on the first branch, and the second heat exchange part is arranged on the second branch, so that the refrigerant flowing out of the second heat exchanger exchanges heat with the refrigerant flowing out of the fourth heat exchanger, and the first heat exchange part is connected to the inlet side of the compressor through the fourth branch; The first heat exchanger includes a third heat exchange part and a fourth heat exchange part for exchanging heat with the third heat exchange part, the third heat exchange part is arranged on the third branch, and the fourth heat exchange part is arranged on the fourth branch; Among them, in the heating mode, the refrigerant flowing out of the first heat exchange part flows to the fourth heat exchange part through the fourth branch, and the refrigerant flowing through the third heat exchange part exchanges heat with the refrigerant after throttling through the first heat exchange part, so that the refrigerant flowing into the fourth heat exchanger can be maintained at a preset exhaust superheat.

2. The direct cooling thermal management system according to claim 1, characterized in that: The fourth branch is provided with a first electronic expansion valve, and the first electronic expansion valve can control the opening degree of the fourth branch.

3. The direct cooling thermal management system according to claim 2, characterized in that: Also includes: A first temperature detection unit is located at the outlet side of the third heat exchange part on the third branch; A first pressure detection unit, located at the outlet side of the compressor; A controller is used to control the first electronic expansion valve according to the collected values ​​of the first temperature detection unit and the first pressure detection unit in a heating mode.

4. The direct cooling thermal management system according to claim 1, characterized in that: The direct cooling thermal management system has a defrost mode. In the defrost mode, the refrigerant flowing out of the compressor flows to the second heat exchanger through the third heat exchange part, and the refrigerant flowing out of the second heat exchanger flows to the compressor through the first heat exchange part, the fourth heat exchange part and the second heat exchange part.

5. The direct cooling thermal management system according to claim 2, characterized in that: Also includes: A second temperature detection unit is located at the inlet side of the compressor; A second pressure detection unit is located at the inlet side of the compressor; A controller is provided for controlling the first electronic expansion valve according to the collected values ​​of the second temperature detection unit and the second pressure detection unit in a defrosting mode.

6. The direct cooling thermal management system according to any one of claims 1 to 5, characterized in that: A heater is provided on the air inlet side of the second heat exchanger.

7. The direct cooling thermal management system according to claim 1, characterized in that: The first branch comprises: a first branch road, connected to the second heat exchanger and the fourth heat exchanger, the refrigerant circuit includes a first one-way valve and a second electronic expansion valve arranged on the first branch road, and the first one-way valve only allows the refrigerant to flow from the second heat exchanger to the fourth heat exchanger, and the first heat exchange part is located in the first branch road; a second branch road, arranged in parallel with the first branch road, and communicating with the second heat exchanger and the first heat exchange part, the refrigerant circuit comprising a third electronic expansion valve arranged on the second branch road, the fourth branch road being connected to the second branch road, and the connection position of the fourth branch road and the second branch road being located at the inlet side of the third electronic expansion valve; The third branch is arranged in parallel with the first branch and connects the fourth heat exchanger and the first heat exchange part. The refrigerant circuit includes a second one-way valve arranged on the third branch, and the second one-way valve only allows the refrigerant to flow from the fourth heat exchanger to the second heat exchanger.

8. The direct cooling thermal management system according to claim 1, characterized in that: The second branch comprises: a fourth branch line, communicating with the multi-way valve and the fourth heat exchanger; The fifth branch is arranged in series with the fourth branch and communicates with the multi-way valve and the compressor inlet. The second heat exchange part is located on the fifth branch.

9. The direct cooling thermal management system according to claim 8, characterized in that: The multi-way valve includes a first interface connected to the first heat exchanger, a second interface connected to the second heat exchanger, a third interface connected to the compressor inlet, and a fourth interface connected to the fourth heat exchanger.

10. An energy storage container, characterized in that: A direct cooling thermal management system comprising any one of claims 1-9.

11. A control method for a thermal management system, characterized in that: A thermal management system suitable for any one of claims 1 to 9, comprising the following steps: In heating mode: Control the first interface and the fourth interface of the multi-way valve to be connected, control the second interface and the third interface to be connected, control the first electronic expansion valve and the third electronic expansion valve to be opened, control the second electronic expansion valve to be closed, and control the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the fourth interface of the multi-way valve, the fourth heat exchanger, the first heat exchange part of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange part of the first heat exchanger in sequence, and merges with the refrigerant flowing out of the first heat exchange part of the third heat exchanger after passing through the third electronic expansion valve, the second heat exchanger, the second interface of the multi-way valve, and the third interface of the multi-way valve in sequence, and the merged refrigerant flows through the second heat exchange part of the third heat exchanger and flows back to the compressor; In defrost mode: Controlling the first interface and the second interface of the multi-way valve to be connected, controlling the first electronic expansion valve to be opened, controlling the second electronic expansion valve and the third electronic expansion valve to be closed, and controlling the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the second interface of the multi-way valve, the second heat exchanger, the first heat exchange part of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange part of the first heat exchanger, the second heat exchange part of the third heat exchanger in sequence and flows back to the compressor; In cooling mode: Control the first interface and the second interface of the multi-way valve to be connected, control the third interface and the fourth interface to be connected, control the second electronic expansion valve to open, control the first electronic expansion valve and the third electronic expansion valve to close, and control the compressor to start, so that the refrigerant discharged from the compressor flows through the third heat exchange part of the first heat exchanger, the first interface of the multi-way valve, the second interface of the multi-way valve, the second heat exchanger, the first heat exchange part of the third heat exchanger, the second electronic expansion valve, the fourth heat exchanger, the fourth interface of the multi-way valve, the third interface of the multi-way valve, the second heat exchange part of the third heat exchanger and flows back to the compressor.

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