A direct-cooling thermal management system, energy storage container and control method

Abstract

The application provides a direct cooling heat management system, an energy storage container and a control method. The direct cooling heat management system is used for heat exchange of 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 connected to form a refrigerant circuit. In the heating mode, the 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, 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, and the refrigerant flowing into the fourth heat exchanger can be kept at a preset temperature. The direct cooling heat management system provided by the application can realize accurate control and adjustment of the superheat degree of the refrigerant flowing into the fourth heat exchanger during heating of the battery by using the first heat exchanger to exchange heat with the refrigerant flowing out of the compressor, and can improve the temperature uniformity of the battery during heating. At the same time, the battery can not be defrosted during heating, and the heating effect is improved.

Description

Technical Field

[0001] This application discloses information in the field of energy storage system technology, specifically relating to a direct cooling thermal management system, an energy storage container, and a control method. Background Technology

[0002] A rack-mounted energy storage system is an energy storage system designed and installed in a rack-like form. It integrates the energy storage system, inverter, and other necessary components and control equipment to achieve the functions of storing and converting electrical energy. With the increasing demand for energy storage, temperature control of the energy storage system is crucial to ensuring its normal operation.

[0003] In the process of realizing this invention, the inventors discovered 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 the heat transfer medium. Heat exchange with the energy storage battery is completed 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 without treating the exhaust superheat. This results in poor consistency and temperature uniformity of the refrigerant flow entering the multiple direct cooling plates, thereby affecting the heating effect of the direct cooling plates on the battery. Summary of the Invention

[0004] In view of this, this application provides a direct cooling thermal management system, an energy storage container, and a control method, which can treat the refrigerant flowing out of the compressor during the heating process of the energy storage battery, thereby improving the temperature uniformity of the battery cells during heating. Simultaneously, it can achieve a defrosting function without cooling the battery cells during heating, effectively solving the problem of the inability to defrost at low temperatures.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] In one aspect, a direct cooling thermal management system is provided for heat exchange of multiple 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 the first branch. The fourth heat exchanger and the inlet side of the compressor are connected through the second branch. The outlet side of the compressor is connected to the third branch.

[0008] The third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchange section is disposed in the first branch, and the second heat exchange section is disposed in 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. The first heat exchange section and the inlet side of the compressor are connected through the fourth branch.

[0009] The first heat exchanger includes a third heat exchange section and a fourth heat exchange section that exchanges heat with the third heat exchange section. The third heat exchange section is disposed in the third branch, and the fourth heat exchange section is disposed in the fourth branch.

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

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

[0012] One feasible implementation also includes:

[0013] The first temperature detection unit is located on the outlet side of the third heat exchange section on the third branch;

[0014] The first pressure detection unit is located on the outlet side of the compressor;

[0015] The controller controls the first electronic expansion valve in heating mode based on the values ​​collected by the first temperature detection unit and the first pressure detection unit.

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

[0017] One feasible implementation also includes:

[0018] The second temperature detection unit is located on the inlet side of the compressor;

[0019] The second pressure detection unit is located on the inlet side of the compressor;

[0020] The controller controls the first electronic expansion valve in defrost mode based on the values ​​collected by the second temperature detection unit and the second pressure detection unit.

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

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

[0023] The first branch circuit connects the second heat exchanger and the fourth heat exchanger. The refrigerant circuit includes a first check valve and a second electronic expansion valve disposed on the first branch circuit. The first check valve only allows refrigerant to flow from the second heat exchanger to the fourth heat exchanger. The first heat exchange section is located in the first branch circuit.

[0024] The second branch is arranged in parallel with the first branch and connects the second heat exchanger and the first heat exchange section. The refrigerant circuit includes a third electronic expansion valve arranged on the second branch. The fourth branch is connected to the second branch, and the connection position of the fourth branch and the second branch is located on 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 section. The refrigerant circuit includes a second one-way valve arranged on the third branch, and the second one-way valve only allows refrigerant to flow from the fourth heat exchanger to the second heat exchanger.

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

[0027] The fourth branch connects the multi-way valve and the fourth heat exchanger;

[0028] The fifth branch is connected in series with the fourth branch and connects the multi-way valve and the compressor inlet. The second heat exchange section is located in the fifth branch.

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

[0030] Secondly, an energy storage container is provided, including the direct cooling and heating management system described in any of the above claims.

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

[0032] In heating mode:

[0033] The system controls the connection of the first and fourth ports of the multi-way valve, the connection of the second and third ports, the opening of the first and third electronic expansion valves, the closing of the second electronic expansion valve, and the starting of the compressor. This causes the refrigerant discharged from the compressor to flow sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the fourth port of the multi-way valve, the fourth heat exchanger, the first heat exchange section of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange section of the first heat exchanger, and the refrigerant flowing out from the first heat exchange section of the third heat exchanger to flow sequentially through the third electronic expansion valve, the second heat exchanger, the second port of the multi-way valve, and the third port of the multi-way valve before merging. The merged refrigerant then flows through the second heat exchange section of the third heat exchanger and returns to the compressor.

[0034] In defrost mode:

[0035] The system controls the first and second ports of the multi-way valve to connect, controls the first electronic expansion valve to open, controls the second and third electronic expansion valves to close, and controls the compressor to start, so that the refrigerant discharged by the compressor flows sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the second port of the multi-way valve, the second heat exchanger, the first heat exchange section of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange section of the first heat exchanger, and the second heat exchange section of the third heat exchanger and flows back to the compressor.

[0036] In cooling mode:

[0037] The system controls the connection of the first and second ports of the multi-way valve, the connection of the third and fourth ports, the opening of the second electronic expansion valve, the closing of the first and third electronic expansion valves, and the starting of the compressor, so that the refrigerant discharged from the compressor flows sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the second port of the multi-way valve, the second heat exchanger, the first heat exchange section of the third heat exchanger, the second electronic expansion valve, the fourth heat exchanger, the fourth port of the multi-way valve, the third port of the multi-way valve, and the second heat exchange section of the third heat exchanger, and then flows back to the compressor.

[0038] The direct cooling and heating management system provided in this application has at least the following beneficial effects:

[0039] During battery heating, the first heat exchanger exchanges heat with the refrigerant flowing from the compressor, enabling precise control and adjustment of the refrigerant superheat flowing to the fourth heat exchanger, thus improving the uniformity of cell temperature during heating. Simultaneously, during heating, by controlling the refrigerant flow direction, the refrigerant from the compressor flows through the first heat exchanger to the second heat exchanger, but not through the fourth heat exchanger. While the refrigerant from the compressor defrosts the second heat exchanger, it does not absorb heat from the cell through the fourth heat exchanger, thereby achieving a defrosting function without cooling the cell during heating, solving the problem of the cell being unable to defrost at low temperatures. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 This 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 direction in heating mode.

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

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

[0045] Reference 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 line; 602. Second branch line; 603. Third branch line; 7. Second branch line; 701. Fourth branch line; 702. Fifth branch line; 8. Third branch line; 9. Fourth branch line; 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 check valve; 17. Second electronic expansion valve; 18. Third electronic expansion valve; 19. Second check valve; 20. Multi-way valve; 21. Gas-liquid separator; 22. Filter. Detailed Implementation

[0046] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] Reference Figures 1-4 This application provides a direct cooling thermal management system for heat exchange of multiple batteries in an energy storage system. The system includes a compressor 1, a first heat exchanger 2, a second heat exchanger 3, a third heat exchanger 4, and a fourth heat exchanger 5 connected in sequence to form a refrigerant circuit. The compressor outlet provides high-temperature and high-pressure gaseous refrigerant. 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 batteries in different modes, thereby realizing the temperature transfer between the refrigerant in the fourth heat exchanger 5 and the batteries.

[0048] The refrigerant circuit includes multiple branches, which connect the various components. Specifically, the second heat exchanger 3 and the fourth heat exchanger 5 are connected by the first branch 6, the fourth heat exchanger 5 is connected to the inlet side of the compressor 1 by the second branch 7, and a third branch 8 is connected to the outlet side of the compressor 1. This allows the high-temperature, high-pressure gaseous refrigerant discharged from the compressor outlet to circulate in heating mode, defrosting mode, or cooling mode through the third branch 8, the first branch 6, and the second branch 7.

[0049] The third heat exchanger 4 includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchange section is located in the first branch 6 and serves as a heat release section, while the second heat exchange section is located in the second branch 7 and serves as a heat absorption section, 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 section exchanges heat with the refrigerant in the second heat exchange section, increasing the subcooling of the liquid refrigerant flowing out of the first heat exchange section and significantly reducing the dryness of the refrigerant flowing to the fourth heat exchanger 5 after throttling. In cooling mode, if the refrigerant that has not been throttled by the third heat exchanger 4 flows directly to the fourth heat exchanger 5, the refrigerant will have a high dryness. This makes it difficult to control the uniform distribution of the refrigerant to the cold plates in the subsequent pipelines, resulting in uneven flow distribution at the terminal PACK. This makes it impossible for each of the fourth heat exchangers 5 to achieve consistent flow distribution and uniform temperature. However, the refrigerant that has been throttled by the third heat exchanger 4 has a significantly reduced dryness of the two-phase state due to the increased subcooling. This greatly reduces the difficulty of flow distribution and can achieve a considerable degree of uniform distribution, ensuring consistent flow distribution in each of the fourth heat exchangers 5. Furthermore, the second heat exchange section exchanges heat with the first heat exchange section, which can completely ensure that the refrigerant entering the second heat exchange section is a two-phase wet vapor with a dryness of less than 1. It also ensures that the entire heat exchange process in the cold plate is a near-constant two-phase state, achieving the temperature uniformity requirement between cells within a single PACK. In addition, the first heat exchange section distributes the flow to multiple fourth heat exchangers 5, which can simultaneously meet the temperature uniformity requirements of cells within the PACK and the average cell temperature uniformity requirements between PACKs, as shown by the fourth heat exchanger 5, thus realizing the need for direct heat exchange of the battery using the refrigerant.

[0050] Furthermore, the first heat exchange section and the inlet side of the compressor 1 are connected via a fourth branch 9, so that the refrigerant flowing out of the first heat exchange section can return to the compressor 1 via the fourth branch 9. The first heat exchanger 2 includes a third heat exchange section and a fourth heat exchange section that exchanges heat with the third heat exchange section. The third heat exchange section is located in the third branch 8, and the fourth heat exchange section is located in the fourth branch 9. In this way, in the heating mode, the refrigerant flowing out of the first heat exchange section flows to the fourth heat exchange section through the fourth branch 9. The refrigerant flowing through the third heat exchange section exchanges heat with the refrigerant that has been throttled through the first heat exchange section, so that the refrigerant flowing into the fourth heat exchanger 5 can be maintained at a preset exhaust superheat. With the above setup, in heating mode, the high-temperature and high-pressure gaseous refrigerant discharged from the compressor 1 is heated by the first heat exchanger 2 and then flows to the fourth heat exchanger 5. The first heat exchanger 2 is used to heat the refrigerant flowing out of the compressor 1, so as to achieve precise control and adjustment of the superheat of the refrigerant flowing to the fourth heat exchanger 5 during heating, thereby improving the uniformity of the battery cell temperature during heating.

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

[0052] In heating mode, the second heat exchange section of the third heat exchanger 4 exchanges heat with the first heat exchange section, which can ensure that the refrigerant entering the second heat exchange section is a two-phase wet vapor with a dryness fraction of less than 1. The evaporation process in the second heat exchanger 3 is only a near-constant two-phase state, which can effectively reduce the difference between the evaporation temperature and the ambient temperature. This eliminates the excessively low evaporation temperature caused by the superheat in the evaporator that absorbs heat from the environment, increases the system flow rate during heating to effectively increase the heating capacity, and improves the heating capacity.

[0053] The above-mentioned heat exchange between the refrigerant discharged from the first heat exchange section of the third heat exchanger 4 and the refrigerant discharged from the outlet of the compressor 1 prevents 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 the preset superheat and the uniform temperature inside the battery cell is guaranteed during heating.

[0054] In cooling mode, refer to Figure 4When the fourth branch 9 is disconnected, the refrigerant, after being compressed by the compressor 1, becomes a high-temperature, high-pressure gaseous refrigerant and flows from the compressor outlet to the third heat exchange section of the first heat exchanger 2. After passing through the third heat exchange section, the refrigerant flows to the second heat exchanger 3 to release heat, forming a medium-temperature, high-pressure liquid refrigerant that flows to the first heat exchange section of the third heat exchanger 4. After releasing heat from the first heat exchange section, 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, low-pressure liquid refrigerant and enters the fourth heat exchanger 5. The low-temperature, low-pressure wet vapor refrigerant with a dryness fraction of less than 1 formed by the refrigerant in the fourth heat exchanger 5 directly exchanging heat with the battery flows through the second branch 7 to the compressor inlet. During this process, the refrigerant in the second branch 7 passes through the second heat exchange section and exchanges heat with the liquid refrigerant in the first heat exchange section, causing the gaseous refrigerant entering the second heat exchange section to absorb heat and then form a low-temperature, low-pressure gaseous refrigerant that enters the compressor inlet. After being compressed by the compressor 1, it becomes a high-temperature, high-pressure gaseous refrigerant and is discharged from the compressor outlet, thus completing one refrigeration cycle.

[0055] During the above process, the fourth branch 9 is disconnected, causing the first heat exchange section of the third heat exchanger 4 to disconnect from the fourth heat exchange section of the first heat exchanger 2. The third heat exchange section of the first heat exchanger 2 is only used as a refrigerant flow path and does not have a refrigerant heat exchange function, making it convenient to switch between cooling mode and heating mode and improving the system working efficiency.

[0056] It should be noted that the fourth heat exchanger 5 is the direct-cooling plate that directly contacts 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, the multiple fourth heat exchangers 5 are connected in parallel, and the multiple fourth heat exchangers 5 are connected to the first branch 6 through a first shut-off valve, and the multiple fourth heat exchangers 5 are connected to the compressor inlet through a second shut-off 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 double-tube structure, or 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 double-tube structure, the third heat exchange section is a first tube structure, and refrigerant flowing from the compressor 1 flows through the first tube structure. The fourth heat exchange section is a second tube structure disposed within the first tube structure, and refrigerant flowing from the fourth branch 9 flows through the second tube structure. The refrigerant flowing at different locations achieves heat transfer through heat exchange on the outer surface of the second tube structure. Of course, when the first heat exchanger 2 is a double-tube structure, the fourth heat exchange section can also be a first tube structure, with refrigerant flowing from the fourth branch 9 flowing through the first tube structure, and the third heat exchange section is a second tube structure disposed within the first tube structure, with refrigerant flowing from the compressor 1 flowing through the second tube structure.

[0058] In one feasible implementation, refer to Figure 1 A first electronic expansion valve 10 is installed on the fourth branch 9. The refrigerant flowing from the first heat exchange section of the third heat exchanger 4 to the fourth heat exchange section of the first heat exchanger 2 passes through the first electronic expansion valve 10 and arrives at the fourth heat exchange section. The first electronic expansion valve 10 can control the opening of the fourth branch 9, enabling it to throttle and control the flow of the refrigerant to the fourth heat exchange section. That is, in heating mode, part of the refrigerant flowing out of the first heat exchange section enters the fourth branch 9 and is converted into a low-pressure, low-temperature two-phase refrigerant under the control of the first electronic expansion valve 10 and sent into the fourth heat exchange section. The first electronic expansion valve 10 indirectly controls the mass flow rate of the refrigerant entering the fourth heat exchange section by controlling the opening, so that the refrigerant flowing from the third heat exchange section to the fourth heat exchanger 5 in heating mode can be maintained at a preset exhaust superheat. In defrost mode, the fourth heat exchange section and the second heat exchange section become the evaporator in defrost mode, so that defrosting does not require absorbing heat from the battery cell, and effective and rapid defrosting can still be achieved when the battery cell temperature is extremely low. It features uniform cell temperature during heating mode, prevents cell temperature drop during defrosting mode, and ensures normal and rapid defrosting even at extremely low cell temperatures.

[0059] In one feasible implementation, refer to Figure 1 The system also includes a first temperature detection unit 11, a first pressure detection unit 12, and a controller. The first temperature detection unit 11 is located at the outlet side of the third heat exchange section on the third branch 8, and 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, used to detect the real-time temperature of the refrigerant flowing out of the third heat exchange section. The first pressure detection unit 12 is preferably a high-pressure sensor, used to detect the pressure of the refrigerant flowing out of the compressor outlet, and converts the acquired refrigerant pressure into a refrigerant saturation temperature. By calculating the difference between the real-time refrigerant temperature and the refrigerant saturation temperature, the refrigerant superheat is determined. In heating mode, the controller controls the first electronic expansion valve 10 based on the values ​​collected by the first temperature detection unit 11 and the first pressure detection unit 12. In this way, in 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 sensor, thereby changing the refrigerant flow from the fourth branch 9 to the fourth heat exchange section, and thus changing the heat exchange capacity of the first heat exchanger 2, ensuring that the refrigerant flowing out of the third heat exchange section is maintained within the preset superheat range.

[0060] Specifically, the exhaust temperature sensor and the high-pressure sensor are connected to the controller. The controller receives refrigerant temperature and pressure information and controls the opening of the first electronic expansion valve 10 based on the temperature and pressure information. This achieves automatic control of the opening of the first electronic expansion valve 10, shortens the response time of the first electronic expansion valve 10, and precisely controls the refrigerant flow rate so that the superheat of the refrigerant entering the fourth heat exchanger 5 is within the preset superheat level, thereby improving the uniform temperature of the battery cells during heating.

[0061] In one optional implementation, the direct cooling thermal management system has a defrosting mode. In defrosting mode, the refrigerant flowing out of compressor 1 flows to the second heat exchanger 3 through the third heat exchange section, and the refrigerant flowing out of the second heat exchanger 3 flows to compressor 1 through the first heat exchange section, the fourth heat exchange section, and the second heat exchange section. In this way, the high-temperature and high-pressure gaseous refrigerant discharged from compressor 1 flows directly to the second heat exchanger 3 after heat exchange, without flowing through the fourth heat exchanger 5. This ensures that the second heat exchanger 3 is defrosted while not absorbing heat from the battery cell, thus achieving defrosting without cooling the battery cell.

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

[0063] The aforementioned defrosting mode is applied to the battery heating process. During battery heating, due to the low ambient temperature, the second heat exchanger 3 experiences frost formation. Therefore, by utilizing the first heat exchanger 2 and the third heat exchanger 4 in conjunction, defrosting the second heat exchanger 3 can be achieved, quickly restoring its heat exchange efficiency and thus improving the overall system performance. Furthermore, during the defrosting operation of the second heat exchanger 3, the existing first heat exchanger 2 and third heat exchanger 4 eliminate the need for an additional defrosting device, optimizing the system structure and reducing operating costs. Preferably, a detection structure or device is provided at the location of the second heat exchanger 3 to determine whether defrosting is required. If defrosting is determined, the flow direction of the high-temperature, high-pressure gaseous refrigerant in the refrigerant circuit is controlled, preventing the high-temperature, high-pressure gaseous refrigerant flowing from the compressor 1 from entering the fourth heat exchanger 5. Instead, it flows through the second heat exchanger 3 and back to the compressor 1, maintaining the battery temperature and achieving defrosting without cooling the battery.

[0064] In one feasible implementation, refer to Figure 1 The system also includes a second temperature detection unit 13, a second pressure detection unit 14, and a controller, both located on the inlet side of the compressor 1. The second temperature detection unit 13 is preferably a return temperature sensor, 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 sensor, used to detect the pressure of the refrigerant about to enter the compressor 1. In defrost mode, the controller controls the first electronic expansion valve 10 based on the values ​​collected by the second temperature detection unit 13 and the second pressure detection unit 14. Thus, in defrost mode, based on the refrigerant temperature obtained by the return temperature sensor and the refrigerant pressure obtained by the low-pressure sensor, the opening of the first electronic expansion valve 10 is adaptively adjusted, changing the refrigerant flow rate from the fourth branch 9 to the fourth heat exchange section, thereby changing the heat exchange capacity of the first heat exchanger 2 and ensuring normal operation of the defrost function.

[0065] The aforementioned controller is communicatively connected to the return temperature sensor and the low-pressure sensor. Preferably, a single controller is used for both heating and defrosting modes. In different modes, the controller can receive temperature and pressure information from different components and control the opening degree of the first electronic expansion valve 10 based on this information. Alternatively, two controllers can be configured, for example, a first controller and a second controller. The first controller is communicatively connected to the exhaust temperature sensor and the high-pressure sensor, while the second controller is communicatively connected to the return temperature sensor and the low-pressure sensor. This ensures that the opening degree of the first electronic expansion valve 10 is controlled by different components in both heating and defrosting modes, meeting different usage requirements.

[0066] In one feasible implementation, refer to Figure 1A heater 15 is installed on the air inlet side of the second heat exchanger 3. The heater 15 is used to heat the air entering the second heat exchanger 3. In this way, in the heating mode, if the ambient temperature is too low, causing the refrigerant temperature to be too low, resulting in insufficient heating capacity, low heating efficiency, system malfunction, or even loss of heating capacity, the heater 15 can heat the air entering the second heat exchanger 3, increase the evaporation temperature, enable the system to operate normally, and increase the heating capacity.

[0067] In one feasible implementation, refer 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 check valve 16 and a second electronic expansion valve 17 disposed on the first branch 601. The first check valve 16 only allows refrigerant to flow from the second heat exchanger 3 to the fourth heat exchanger 5. The first heat exchange section 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 check valve 16.

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

[0069] The first branch 6 also includes a third branch 603, which is connected in parallel with the first branch 601 and connects the fourth heat exchanger 5 and the first heat exchange section. The refrigerant circuit includes a second check valve 19 installed on the third branch 603, which only allows 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 this connection end is located between the first check valve 16 and the third heat exchanger 4.

[0070] In one feasible implementation, refer to Figure 1The second branch 7 includes a fourth branch 701 and a fifth branch 702. The fourth branch 701 connects the multi-way valve 20 and the fourth heat exchanger 5. The fifth branch 702 is connected in series with the fourth branch 701 and connects the multi-way valve 20 and the compressor inlet. The second heat exchange section is located on the fifth branch 702, and the connection point between the fourth branch 9 and the fifth branch 702 is located on the inlet side of the second heat exchange section of the third heat exchanger 4. Thus, in heating mode, the refrigerant in the fourth branch 9 flows through the fourth heat exchange section of the first heat exchanger 2 and can merge with the refrigerant flowing from the second heat exchanger 3 to the compressor inlet. They then enter the second heat exchange section of the first heat exchanger 2 to absorb heat and flow to the compressor inlet.

[0071] According to the above configuration, in both heating and cooling modes, the refrigerant in the first and second heat exchange sections exchanges heat in opposite directions. This maximizes the temperature difference between the refrigerants, improves heat exchange efficiency, and avoids insufficient heat exchange caused by excessively low or high temperature crossover points. Furthermore, for the same amount of heat transfer, a smaller heat transfer area is required, and the local temperature difference of the refrigerant at any point on the heat transfer surface is relatively uniform. In both heating and defrosting modes, the refrigerant in the third and fourth heat exchange sections also exchanges heat in opposite directions, which similarly improves heat exchange efficiency.

[0072] Furthermore, based on the above embodiment, a filter 22 is provided between the third heat exchanger 4 and the fourth heat exchanger 5. The filter 22 is provided on the first branch 601 and 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 one feasible implementation, the multi-port 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] A multi-way valve 20 is used to control the different flow directions of the refrigerant in the refrigerant circuit during heating, defrosting, and cooling modes. Specifically, in heating mode, the first and fourth ports are connected, and the second and third ports are connected. This allows the high-temperature, high-pressure gaseous refrigerant discharged from the compressor outlet to pass through the first and fourth ports before reaching the fourth heat exchanger 5. Similarly, the low-temperature, low-pressure, wet vapor refrigerant with a dryness fraction less than 1 discharged from the second heat exchanger 3 passes through the second and third ports, absorbs heat in the third heat exchanger 4, and becomes superheated gas before reaching the compressor inlet, completing one heating cycle. In cooling mode, the first and second ports are connected, and the third and fourth ports are connected. This allows the high-temperature, high-pressure gaseous refrigerant discharged from the compressor outlet to pass through the first and second ports before reaching the second heat exchanger 3. Similarly, the low-temperature, low-pressure, wet vapor refrigerant with a dryness fraction less than 1 discharged from the fourth heat exchanger 5 passes through the third and fourth ports, absorbs heat in the third heat exchanger 4, and becomes superheated gas before reaching the compressor inlet, completing one cooling cycle. In defrost mode, the first and second interfaces are connected, and the third and fourth interfaces are connected, so that the high-temperature and high-pressure gaseous refrigerant discharged from the compressor outlet must pass through the first and second interfaces before reaching the second heat exchanger 3. A multi-way valve 20 is used to change the refrigerant flow direction, and the structure is simple and easy to operate.

[0075] The refrigerant circuit includes a gas-liquid separator 21. Before the refrigerant enters the compressor inlet, the gas-liquid separator 21 separates the gaseous and liquid refrigerant, storing the separated liquid refrigerant. This ensures that the compressor 1 inlet only draws in gaseous refrigerant, preventing liquid refrigerant from entering the compressor 1 and causing liquid slugging. Simultaneously, a low-pressure sensor and a return gas temperature sensor are positioned between the compressor inlet and the gas-liquid separator 21. These sensors detect the pressure and temperature of the refrigerant entering the compressor 1, respectively, and provide real-time feedback to the first electronic expansion valve 10 during 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 maintained within the optimal range.

[0076] Secondly, an energy storage container is provided, which belongs to the field of energy storage and has multiple energy storage batteries. The aforementioned direct cooling and heat management system is used to perform direct cooling and heat exchange on the energy storage batteries to ensure normal operation of the energy storage batteries.

[0077] Thirdly, a control method for a thermal management system is provided, suitable for controlling the aforementioned thermal management system, comprising the following steps:

[0078] In heating mode:

[0079] The system controls the connection of the first and fourth ports of the multi-way valve 20, the connection of the second and third ports, the opening of the first electronic expansion valve 10 and the third electronic expansion valve 18, the closing of the second electronic expansion valve 17, and the start of the compressor 1. This causes the refrigerant discharged from the compressor 1 to flow sequentially through the third heat exchange section of the first heat exchanger 2, the first port of the multi-way valve 20, the fourth port of the multi-way valve 20, the fourth heat exchanger 5, the first heat exchange section of the third heat exchanger 4, the first electronic expansion valve 10, and the fourth heat exchange section of the first heat exchanger 2. The refrigerant discharged from the first heat exchange section of the third heat exchanger 4 then flows sequentially through the third electronic expansion valve 18, the second heat exchanger 3, the second port of the multi-way valve 20, and the third port of the multi-way valve 20 before merging with the refrigerant. The merged refrigerant then flows through the second heat exchange section of the third heat exchanger 4 and returns to the compressor 1.

[0080] In defrost mode:

[0081] The system controls the connection of the first and second ports of the multi-way valve 20, controls the opening of the first electronic expansion valve 10, controls the closing of the second electronic expansion valve 17 and the third electronic expansion valve 18, and controls the start of the compressor 1, so that the refrigerant discharged from the compressor 1 flows sequentially through the third heat exchange section of the first heat exchanger 2, the first port of the multi-way valve 20, the second port of the multi-way valve 20, the second heat exchanger 3, the first heat exchange section of the third heat exchanger 4, the first electronic expansion valve 10, the fourth heat exchange section of the first heat exchanger 2, the second heat exchange section of the third heat exchanger 4, and then flows back to the compressor 1.

[0082] In cooling mode:

[0083] The system controls the connection of the first and second ports of the multi-way valve 20, the connection of the third and fourth ports, the opening of the second electronic expansion valve 17, the closing of the first electronic expansion valve 10 and the third electronic expansion valve 18, and the start of the compressor 1, so that the refrigerant discharged from the compressor 1 flows sequentially through the third heat exchange section of the first heat exchanger 2, the first port of the multi-way valve 20, the second port of the multi-way valve 20, the second heat exchanger 3, the first heat exchange section of the third heat exchanger 4, the second electronic expansion valve 17, the fourth heat exchanger 5, the fourth port of the multi-way valve 20, the third port of the multi-way valve 20, and the second heat exchange section of the third heat exchanger 4 and flows back to the compressor 1.

[0084] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0085] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily 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 this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A direct cooling and heating management system, characterized in that, Used for heat exchange of 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 connected in sequence to form a refrigerant circuit; The refrigerant circuit includes multiple branches. The second heat exchanger and the fourth heat exchanger are connected through the first branch. The fourth heat exchanger and the inlet side of the compressor are connected through the second branch. The outlet side of the compressor is connected to the third branch. The third heat exchanger includes a first heat exchange section and a second heat exchange section that exchanges heat with the first heat exchange section. The first heat exchange section is disposed in the first branch, and the second heat exchange section is disposed in 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. The first heat exchange section and the inlet side of the compressor are connected through the fourth branch. The first heat exchanger includes a third heat exchange section and a fourth heat exchange section that exchanges heat with the third heat exchange section. The third heat exchange section is disposed in the third branch, and the fourth heat exchange section is disposed in the fourth branch. In the heating mode, the refrigerant flowing out of the first heat exchange section flows to the fourth heat exchange section through the fourth branch. The refrigerant flowing through the third heat exchange section exchanges heat with the refrigerant flowing through the first heat exchange section and throttled by the first electronic expansion valve, so that the refrigerant flowing into the fourth heat exchanger can be maintained at a preset exhaust superheat.

2. The direct cooling and heating management system according to claim 1, characterized in that, A first electronic expansion valve is provided on the fourth branch, which can control the opening degree of the fourth branch.

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

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

5. The direct cooling and heating management system according to claim 2, characterized in that, Also includes: The second temperature detection unit is located on the inlet side of the compressor; The second pressure detection unit is located on the inlet side of the compressor; The controller controls the first electronic expansion valve in defrost mode based on the values ​​collected by the second temperature detection unit and the second pressure detection unit.

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

7. The direct cooling and heating management system according to claim 1, characterized in that, The first branch includes: The first branch circuit connects the second heat exchanger and the fourth heat exchanger. The refrigerant circuit includes a first check valve and a second electronic expansion valve disposed on the first branch circuit. The first check valve only allows refrigerant to flow from the second heat exchanger to the fourth heat exchanger. The first heat exchange section is located in the first branch circuit. The second branch is arranged in parallel with the first branch and connects the second heat exchanger and the first heat exchange section. The refrigerant circuit includes a third electronic expansion valve arranged on the second branch. The fourth branch is connected to the second branch, and the connection position of the fourth branch and the second branch is located on 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 section. The refrigerant circuit includes a second one-way valve arranged on the third branch, and the second one-way valve only allows refrigerant to flow from the fourth heat exchanger to the second heat exchanger.

8. The direct cooling and heating management system according to claim 1, characterized in that, The second branch includes: The fourth branch connects the multi-way valve and the fourth heat exchanger; The fifth branch is connected in series with the fourth branch and connects the multi-way valve and the compressor inlet. The second heat exchange section is located in the fifth branch.

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

10. An energy storage container, characterized in that, Includes the direct cooling and heating management system as described in any one of claims 1-9.

11. A control method for a thermal management system, characterized in that, A direct-cooling thermal management system suitable for any one of claims 1-9, the direct-cooling thermal management system comprising a multi-way valve, a first electronic expansion valve, a second electronic expansion valve, and a third electronic expansion valve; the multi-way valve is connected to a fourth heat exchanger via a fourth branch, and 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; the first electronic expansion valve is disposed in the fourth branch, the second electronic expansion valve is disposed in the first branch between the second heat exchanger and the fourth heat exchanger, and the third electronic expansion valve is disposed in the second branch between the second heat exchanger and the fourth heat exchanger; the control method comprises the following steps: In heating mode: The system controls the connection of the first and fourth ports of the multi-way valve, the connection of the second and third ports, the opening of the first and third electronic expansion valves, the closing of the second electronic expansion valve, and the starting of the compressor. This causes the refrigerant discharged from the compressor to flow sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the fourth port of the multi-way valve, the fourth heat exchanger, the first heat exchange section of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange section of the first heat exchanger, and the refrigerant flowing out from the first heat exchange section of the third heat exchanger to flow sequentially through the third electronic expansion valve, the second heat exchanger, the second port of the multi-way valve, and the third port of the multi-way valve before merging. The merged refrigerant then flows through the second heat exchange section of the third heat exchanger and returns to the compressor. In defrost mode: The system controls the first and second ports of the multi-way valve to connect, controls the first electronic expansion valve to open, controls the second and third electronic expansion valves to close, and controls the compressor to start, so that the refrigerant discharged by the compressor flows sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the second port of the multi-way valve, the second heat exchanger, the first heat exchange section of the third heat exchanger, the first electronic expansion valve, the fourth heat exchange section of the first heat exchanger, and the second heat exchange section of the third heat exchanger and flows back to the compressor. In cooling mode: The system controls the connection of the first and second ports of the multi-way valve, the connection of the third and fourth ports, the opening of the second electronic expansion valve, the closing of the first and third electronic expansion valves, and the starting of the compressor, so that the refrigerant discharged from the compressor flows sequentially through the third heat exchange section of the first heat exchanger, the first port of the multi-way valve, the second port of the multi-way valve, the second heat exchanger, the first heat exchange section of the third heat exchanger, the second electronic expansion valve, the fourth heat exchanger, the fourth port of the multi-way valve, the third port of the multi-way valve, and the second heat exchange section of the third heat exchanger, and then flows back to the compressor.

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