A direct cooling system for a coolant heater and power conversion device

Abstract

This application discloses a direct cooling system for a refrigerant heater and power conversion device, belonging to the field of air conditioning technology. The refrigerant heater includes a first plate, a second plate, and a heating element. The first and second plates are fitted together. The first plate has a receiving cavity, and the heating element is disposed within the receiving cavity. The first plate also has a through hole and a second through hole. The second plate has a refrigerant cavity, which communicates with the first and second through holes. By installing the heating element within the receiving cavity of the first plate, the first and second plates are fitted together to form a thermally conductive contact, transferring the heat generated by the heating element to the second plate for indirect heating of the refrigerant within the refrigerant cavity. When the refrigerant flows through the first and second through holes, it can be directly heated by the first plate, reducing contact between the refrigerant and the low-temperature external environment during its flow into or out of the refrigerant cavity, resulting in better heating performance. Simultaneously, its overall structure is more compact and occupies less space.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a direct cooling system for a refrigerant heater and power conversion device. Background Technology

[0002] With the booming development of the home appliance industry, people have increasingly higher requirements for the performance of direct cooling systems in power conversion devices, especially their performance in extreme environments. The application of refrigerant heaters in the direct cooling systems of power conversion devices can solve defrosting problems and low heat exchange efficiency. However, conventional refrigerant heaters have poor heating performance. Utility Model Content

[0003] This application provides a refrigerant heater to solve the technical problem of poor heating effect of refrigerant heaters; this application also provides a direct cooling system for a power conversion device.

[0004] Technical solution: The refrigerant heater disclosed in this application includes a first plate, a second plate, and a heating element;

[0005] The first plate and the second plate are attached to each other, and the first plate is provided with a receiving cavity, and the heating element is disposed in the receiving cavity;

[0006] The first plate is also provided with a through hole and a second hole, and the second plate has a refrigerant cavity, which is connected to the first hole and the second hole respectively.

[0007] In some embodiments, there are multiple first plates and multiple second plates, and the multiple first plates and multiple second plates are stacked and arranged alternately. One end of the refrigerant cavity of an adjacent second plate is connected to the first hole in sequence; the other end of the refrigerant cavity of an adjacent second plate is connected to the second hole in sequence.

[0008] In some embodiments, the opening of the refrigerant cavity is located on the side of the second plate facing the first plate, and the first plate covers the opening;

[0009] The second plate and the first plate together enclose the refrigerant cavity.

[0010] In some embodiments, the first plate and the second plate are arranged along a first direction, the first plate has an assembly opening on one side of the second direction, the assembly opening is in communication with the receiving cavity, and the first direction is perpendicular to the second direction;

[0011] The heating element passes through the assembly opening along the second direction and is housed within the receiving cavity.

[0012] In some embodiments, a thermally conductive layer is further included, which is coated on the outer surface of the heating element and in contact with the first plate.

[0013] In some embodiments, a third hole is formed on the first plate, and the refrigerant heater further includes a temperature sensor disposed in the third hole.

[0014] In some embodiments, the refrigerant cavity is provided with a plurality of guide plates, which are arranged at intervals and divide the refrigerant cavity into a plurality of flow channel units, which are interconnected.

[0015] In some embodiments, the refrigerant cavity includes a first region, a second region, and a third region, the second region being located between the first region and the third region, and the second plate having an inlet and an outlet communicating with the refrigerant cavity, the inlet being disposed in the first region and the outlet being disposed in the third region;

[0016] Multiple guide plates are at least partially disposed in the first region, with one end disposed at the liquid inlet and the other end extending toward the side where the liquid outlet is located. Multiple guide plates are at least partially disposed in the third region, with one end disposed at the liquid outlet and the other end extending toward the side where the liquid inlet is located. Multiple guide plates are at least partially disposed in the second region and arranged in a fishbone shape.

[0017] In some embodiments, a third plate is further included, the third plate being disposed on one side of the refrigerant heater in a first direction, the third plate being provided with a first port and a second port, the first port and the second port being respectively connected to the refrigerant cavity, and the first port and the second port being located diagonally opposite to each other on the third plate;

[0018] Alternatively, it may also include a third plate and a fourth plate, wherein the third plate is disposed on one side of the refrigerant heater in the first direction, and the fourth plate is disposed on the other side of the refrigerant heater in the first direction, wherein the third plate has a first opening and the fourth plate has a second opening.

[0019] This application also discloses a direct cooling system for a power conversion device, characterized in that it includes: an air-cooled heat exchanger, a compressor, a four-way valve, an inner heat exchanger, and an electronic expansion valve, wherein the air-cooled heat exchanger, the compressor, the four-way valve, the inner heat exchanger, and the electronic expansion valve are connected in series to form a direct cooling flow path.

[0020] The direct cooling system of the power conversion device also includes a refrigerant heater as described in the above embodiment. The refrigerant heater is connected in series in the direct cooling flow path and is located between the air-cooled heat exchanger and the suction port of the compressor.

[0021] Beneficial Effects: The refrigerant heater in this embodiment includes a first plate, a second plate, and a heating element. The first and second plates are fitted together. The first plate has a receiving cavity, and the heating element is disposed within the receiving cavity. The first plate also has a through hole and a second hole. The second plate has a refrigerant cavity, which communicates with the first and second holes respectively. By installing the heating element within the receiving cavity of the first plate, the first and second plates are fitted together to form a thermally conductive contact, thereby transferring the heat generated by the heating element to the second plate for indirect heating of the refrigerant within the refrigerant cavity. When the refrigerant flows through the first and second holes, it can be directly heated by the first plate, reducing contact between the refrigerant and the external low-temperature environment when flowing into or out of the refrigerant cavity, resulting in better heating performance. Simultaneously, its overall structural layout is more compact and occupies less space.

[0022] The direct cooling system of the power conversion device in this application includes the refrigerant heater as described in the above embodiments. Therefore, it can have all the technical features and effects of the above-described refrigerant heater, which will not be repeated here. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a three-dimensional structural diagram of the refrigerant heater according to an embodiment of this application;

[0025] Figure 2 This is an explosion diagram of the refrigerant heater according to an embodiment of this application. Only the second and third plates on the explosion side are shown in the diagram. At the same time, a set of heating elements and temperature sensors are hidden in the diagram.

[0026] Figure 3 This is a right-side schematic diagram of the refrigerant heater according to an embodiment of this application;

[0027] Figure 4 This is a schematic diagram of the structure of the first plate in the refrigerant heater according to an embodiment of this application. The figure also discloses the heating element and the temperature sensor.

[0028] Figure 5 This is a schematic diagram of the main structure of the second plate in the refrigerant heater according to an embodiment of this application;

[0029] Figure 6 This is a schematic diagram of the direct cooling system of the power conversion device according to an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 10. First plate; 20. Second plate; 30. Heating element; 100. Receptacle; 101. First hole; 102. Second hole; 200. Refrigerant cavity; 201. Opening; X, First direction; Y, Second direction; 103. Assembly port; 40. Thermal conductive layer; 104. Third hole; 50. Temperature sensor; 60. Guide plate; 600. Flow channel unit; 210. First region; 220. Second region; 230. Third region; 202. Liquid inlet; 203. Liquid outlet; 90. Third plate; 901. First opening; 902. Second opening; 91. Fourth plate;

[0032] 1. Refrigerant heater; 2. Compressor; 3. Air-cooled heat exchanger; 4. Inner heat exchanger; 5. Electronic expansion valve; 6. Four-way valve; 7. Direct cooling flow path. Detailed Implementation

[0033] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0034] In the description of this application, it should be understood that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. In the description of this application, "multiple" means two or more, and "at least one" can refer to one, two, or more, unless otherwise explicitly specified. The terms "first," "second," and "third," etc., are only for the convenience of description and are used to name parts or embodiments by number, and do not imply any order of importance between the parts or embodiments.

[0035] As a preamble to the embodiments of this application, a refrigerant heater is used in the direct cooling system of a power conversion device to solve the defrosting problem and the problem of low heat exchange efficiency. However, conventional refrigerant heaters have poor heating performance. At an ambient temperature of -30°C, they cannot increase the suction temperature and suction pressure of the compressor, making it impossible for the compressor to operate normally.

[0036] In view of this, embodiments of this application provide a refrigerant heater, which aims to solve at least one of the above-mentioned technical problems.

[0037] Please see Figure 1 and Figure 2As shown, a refrigerant heater 1 disclosed in this application includes a first plate 10, a second plate 20, and a heating element 30; the first plate 10 and the second plate 20 are fitted together, the first plate 10 is provided with a receiving cavity 100, and the heating element 30 is disposed in the receiving cavity 100; the first plate 10 is also provided with a through first hole 101 and a second hole 102 (e.g., ...). Figure 4 The second plate 20 has a refrigerant cavity 200, which is connected to the first hole 101 and the second hole 102. It should be understood that the first plate 10 and the second plate 20 are made of a metal material with good thermal conductivity, such as aluminum, stainless steel, or alloys. The first hole 101 and the second hole 102 can serve as the outlet and inlet of the refrigerant cavity 200, respectively.

[0038] It is important to understand that by installing the heating element 30 within the accommodating cavity 100 of the first plate 10, the first plate 10 and the second plate 20 are brought into thermal contact, allowing the heat generated by the heating element 30 to be transferred to the second plate 20 for indirect heating of the refrigerant in the refrigerant cavity 200. When the refrigerant flows through the first hole 101 and the second hole 102, it can be directly heated by the first plate 10, reducing contact between the refrigerant and the low-temperature external environment as it flows into or out of the refrigerant cavity 200, resulting in better heating performance. Simultaneously, its overall structural layout is more compact and occupies less space.

[0039] The first plate 10 and the second plate 20 are bonded together, and their thermally conductive contact surfaces can be flexibly designed. For example, by bonding the large surfaces of the first plate 10 and the second plate 20 together, the thermally conductive area is larger, the heating is more uniform, and the heating efficiency is higher. In some embodiments, the first plate 10 and the second plate 20 are brazed or laser-welded to form a double-layer structure, thereby forming a three-layer heat transfer structure consisting of a heat source, a thermally conductive layer 40, and a cooling medium. This enables close-range heating of the cooling medium and improves heating efficiency. At the same time, the structural layout is more compact, and the modular design facilitates maintenance.

[0040] Please see Figure 1 and Figure 2As shown, in some embodiments, there are multiple first plates 10 and multiple second plates 20, which are stacked and alternately arranged. One end of the refrigerant cavity 200 of adjacent second plates 20 is connected sequentially through a first hole 101; the other end of the refrigerant cavity 200 of adjacent second plates 20 is connected sequentially through a second hole 102. It should be understood that by using multiple layers of first plates 10 and multiple layers of second plates 20 to be stacked alternately, a three-dimensional heat exchange network is formed, increasing the capacity of the refrigerant participating in heat exchange. At the same time, the second plates 20 stacked on both sides of the first plate 10 can participate in heat exchange with the first plate 10, improving heat utilization efficiency. Furthermore, the overall structure is more compact. Adjacent refrigerant cavities 200 are connected through the first hole 101 and the second hole 102, allowing the refrigerant in different refrigerant cavities 200 to flow through the first hole 101 and the second hole 102, achieving temperature uniformity of the refrigerant in each refrigerant cavity 200.

[0041] In some embodiments, multiple refrigerant chambers 200 form parallel flow paths. It is important to understand that the parallel flow paths mean that the refrigerant can enter each refrigerant chamber 200 through the first hole 101, with flow distributed to each layer, and then flow out from the second holes 102 of each refrigerant chamber 200. This adapts to applications with higher heat exchange demands and improves overall heat exchange efficiency. Simultaneously, the parallel arrangement of multiple refrigerant chambers 200 achieves uniform flow distribution, reduces flow deviation between different layers, and can adapt to high-flow-rate scenarios. Furthermore, it features flexible adjustment of each layer and facilitates maintenance and replacement.

[0042] In some embodiments, multiple refrigerant chambers 200 form a series flow path, meaning that the refrigerant flows through different refrigerant chambers 200 in sequence through the first hole 101 or the second hole 102, achieving layer-by-layer heating and enhanced heating to achieve a wider temperature rise and meet the heating requirements of low-temperature environments. Simultaneously, it enables uniform temperature output of the refrigerant, avoiding excessively large temperature differences in the output refrigerant.

[0043] Please see Figure 2 As shown, in some embodiments, the opening 201 of the refrigerant cavity 200 is located on the side of the second plate 20 facing the first plate 10, and the first plate 10 covers the opening 201; the second plate 20 and the first plate 10 enclose the refrigerant cavity 200. It should be understood that by covering the opening 201 of the refrigerant cavity 200 of the second plate 20 with the first plate 10, there is no obstruction between the refrigerant cavity 200 of the second plate 20 and the first plate 10. The outer surface of the first plate 10 can come into close contact with the refrigerant inside the refrigerant cavity 200, resulting in lower thermal resistance, higher heat conduction efficiency, and improved heat utilization. Simultaneously, the size of the refrigerant heater 1 is further reduced, minimizing space occupation.

[0044] Please see Figure 2 As shown, in some embodiments, the first plate 10 and the second plate 20 are arranged along the first direction X. The first plate 10 has an assembly opening 103 on one side of the second direction Y, which communicates with the receiving cavity 100. The first direction X is perpendicular to the second direction Y. The heating element 30 passes through the assembly opening 103 along the second direction Y and is housed in the receiving cavity 100. It should be understood that by using the through-hole method to house the heating element 30 after passing through the assembly opening 103, it is easy to install and easier to maintain and repair. In case of damage to the heating element 30, it can be quickly replaced.

[0045] It should be understood that the heating element 30 includes a heating element and leads. The heating element is disposed within the accommodating cavity 100, and the leads are connected to the heating element and extend at least partially to the outside of the first plate 10. The heating element includes a PTC (Positive Temperature Coefficient) ceramic plate and electrode plates disposed on opposite sides of the PTC ceramic plate. Specifically, the PTC heating element is formed by arranging the PTC ceramic plate, electrode plates, and curing adhesive through a process of arranging the plates, applying adhesive, and high-temperature curing. The electrode plates are connected to an external circuit via leads. The heating element has low thermal resistance, high heat exchange efficiency, high safety performance, and long lifespan. Furthermore, it is easy to disassemble and replace.

[0046] Please see Figure 1 As shown, in some embodiments, a thermally conductive layer 40 is further included. The thermally conductive layer 40 is coated on the outer surface of the heating element 30 and contacts the first plate 10. It should be understood that by wrapping the heating element 30 with the thermally conductive layer 40, the heat conduction efficiency between the heating element 30 and the first plate 10 can be further improved, the thermal resistance can be reduced, and the heat transfer loss can be decreased. The thermally conductive layer 40 can be a high-temperature resistant thermally conductive silicone grease.

[0047] Please see Figure 2 As shown, in some embodiments, a third hole 104 is formed on the first plate 10, and the refrigerant heater 1 also includes a temperature sensor 50, which is disposed within the third hole 104. It should be understood that by forming the third hole 104 on the first plate 10, extending the third hole 104 into the first plate 10 near the receiving cavity 100, the temperature of the first plate 10 is detected by the temperature sensor 50 to prevent the first plate 10 from overheating and improve safety.

[0048] Please see Figure 5As shown, in some embodiments, a plurality of guide vanes 60 are provided inside the refrigerant cavity 200. The guide vanes 60 are arranged at intervals and divide the refrigerant cavity 200 into a plurality of flow channel units 600, which are interconnected. It should be understood that by providing a plurality of guide vanes 60 inside the refrigerant cavity 200, the refrigerant flowing into the refrigerant cavity 200 is diverted through the flow channel units 600, thereby further improving the heat exchange efficiency of the refrigerant, enhancing the flow uniformity, and preventing the refrigerant from flowing off course or overheating locally within the refrigerant cavity 200.

[0049] Please see Figure 5 As shown, in some embodiments, the refrigerant cavity 200 includes a first region 210, a second region 220, and a third region 230. The second region 220 is located between the first region 210 and the third region 230. The second plate 20 has an inlet 202 and an outlet 203 communicating with the refrigerant cavity 200. The inlet 202 is located in the first region 210, and the outlet 203 is located in the third region 230. A plurality of guide plates 60 are at least partially located in the first region 210, with one end located at the inlet 202 and the other end extending toward the side where the outlet 203 is located. A plurality of guide plates 60 are at least partially located in the third region 230, with one end located at the outlet 203 and the other end extending toward the side where the inlet 202 is located. A plurality of guide plates 60 are at least partially located in the second region 220 and are arranged in a herringbone pattern. By constructing a tortuous flow channel within the refrigerant cavity 200 using the guide plate 60, the heat exchange path is increased, the heat exchange time is extended, the temperature uniformity is improved, and the pressure inside the flow channel is reduced.

[0050] Please see Figure 2As shown, in some embodiments, a third plate 90 is also included. The third plate 90 is disposed on one side of the refrigerant heater 1 in the first direction X. The third plate 90 has a first opening 901 and a second opening 902, which are respectively connected to the refrigerant cavity 200. The first opening 901 and the second opening 902 are located diagonally opposite each other on the third plate 90. It should be understood that the first plate 10 and the second plate 20 are arranged alternately. The side of the refrigerant heater 1 in the first direction X can be either the first plate 10 or the second plate 20. In this case, by adding the third plate 90, the third plate 90 has higher structural strength and can provide external protection for the first plate 10 or the second plate 20 that is attached to it, preventing the first plate 10 or the second plate 20 from being deformed or damaged by external forces. In some embodiments, the third plate 90 is attached to the first plate 10, and the first port 901 communicates with the first hole 101, and the second port 902 communicates with the second hole 102. In some embodiments, the third plate 90 is attached to the second plate 20, the second port 902 communicates with the liquid inlet 202, and the first port 901 communicates with the liquid outlet 203.

[0051] In some embodiments, a third plate 90 and a fourth plate 91 (e.g.) are also included. Figure 3 The third plate 90 is disposed on one side of the refrigerant heater 1 in the first direction X, and the fourth plate 91 is disposed on the other side of the refrigerant heater 1 in the first direction X. The third plate 90 has a first port 901, and the fourth plate 91 has a second port 902 (not shown). It should be understood that by adding the third plate 90 and the fourth plate 91, the refrigerant heater 1 is protected on both sides in the first direction X, preventing the first plate 10 and the second plate 20 from being deformed or damaged by external forces. In some embodiments, the first port 901 and the second port 902 can be disposed on either the third plate 90 or the fourth plate 91. In some embodiments, the first port 901 can be disposed on the third plate 90, and the second port 902 can be disposed on the fourth plate 91, one for liquid inlet and the other for liquid outlet.

[0052] It should be understood that the third plate 90 is brazed or laser-welded to one of the first plate 10 and the second plate 20, and the fourth plate 91 is brazed or laser-welded to the other of the first plate 10 and the second plate 20. The third plate 90 and the fourth plate 91 can form a shell to provide all-round protection for the stacked first plate 10 and the second plate 20. At the same time, the shell can increase the thermal insulation performance and improve the heat utilization rate.

[0053] Please see Figure 6As shown in the illustration, this application also discloses a direct cooling system for a power conversion device, characterized by comprising: an air-cooled heat exchanger 3, a compressor 2, a four-way valve 6, an inner heat exchanger 4, and an electronic expansion valve 5. The air-cooled heat exchanger 3, compressor 2, four-way valve 6, inner heat exchanger 4, and electronic expansion valve 5 are connected in series to form a direct cooling flow path 7. The direct cooling system of the power conversion device also includes a refrigerant heater 1 as described in the above embodiment. The refrigerant heater 1 is connected in series on the direct cooling flow path 7 and is located between the air-cooled heat exchanger 3 and the suction port of the compressor 2. It should be understood that the refrigerant heater 1 is connected in series on the path between the air-cooled heat exchanger 3 and the suction port of the compressor 2 to heat the refrigerant exiting the suction port of the compressor 2, enabling the compressor 2 of the direct cooling system of the power conversion device to operate normally in an ambient temperature of -30°C.

[0054] The heating element 30 in this application is electrically heated and has three temperature settings. In the first heating mode, when the external ambient temperature is >-10℃ and the suction temperature is <-10℃, the refrigerant heater 1 is activated at the low setting. When the suction temperature is >-2℃, the refrigerant heater 1 is deactivated. In the second heating mode, when -20℃ < external ambient temperature ≤-10℃, the refrigerant heater 1 is activated at the medium setting, switching between the medium and low settings to ensure the suction temperature is ≥-15℃. In the third heating mode, when -30℃ < external ambient temperature ≤-20℃, the refrigerant heater 1 is activated at the high setting, switching between the high and medium settings to ensure the suction temperature is ≥-15℃. In the defrost mode, the refrigerant heater 1 is activated, improving the defrost speed and effect and reducing the impact damage caused by liquid entering the compressor cylinder 2.

[0055] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0056] The direct cooling system of the refrigerant heater and power conversion device provided in the embodiments of this application has been described in detail above, and specific examples have been used to illustrate the principle and implementation of this application. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A refrigerant heater, characterized in that, It includes a first plate (10), a second plate (20), and a heating element (30); The first plate (10) and the second plate (20) are attached to each other. The first plate (10) is provided with a receiving cavity (100), and the heating element (30) is disposed in the receiving cavity (100). The first plate (10) is also provided with a through first hole (101) and a second hole (102), and the second plate (20) has a refrigerant cavity (200), which is connected to the first hole (101) and the second hole (102) respectively.

2. The refrigerant heater according to claim 1, characterized in that, There are multiple first plates (10) and multiple second plates (20), and the multiple first plates (10) and multiple second plates (20) are stacked and arranged alternately. One end of the refrigerant cavity (200) of adjacent second plates (20) is connected in sequence through the first hole (101); the other end of the refrigerant cavity (200) of adjacent second plates (20) is connected in sequence through the second hole (102).

3. The refrigerant heater according to claim 1, characterized in that, The opening (201) of the refrigerant chamber (200) is located on the side of the second plate (20) facing the first plate (10), and the first plate (10) covers the opening (201); The second plate (20) and the first plate (10) enclose the refrigerant cavity (200).

4. The refrigerant heater according to claim 1, characterized in that, The first plate (10) and the second plate (20) are arranged along the first direction (X). The first plate (10) has an assembly port (103) on one side of the second direction (Y). The assembly port (103) is connected to the accommodating cavity (100). The first direction (X) is perpendicular to the second direction (Y). The heating element (30) passes through the assembly opening (103) along the second direction (Y) and is housed in the receiving cavity (100).

5. The refrigerant heater according to claim 4, characterized in that, It also includes a heat-conducting layer (40), which is coated on the outer surface of the heating element (30) and in contact with the first plate (10).

6. The refrigerant heater according to claim 1, characterized in that, A third hole (104) is provided on the first plate (10), and the refrigerant heater also includes a temperature sensor (50), which is disposed in the third hole (104).

7. The refrigerant heater according to claim 1, characterized in that, The refrigerant cavity (200) is provided with a plurality of guide plates (60), which are arranged at intervals and divide the refrigerant cavity (200) into a plurality of flow channel units (600), which are interconnected.

8. The refrigerant heater according to claim 7, characterized in that, The refrigerant cavity (200) includes a first region (210), a second region (220) and a third region (230). The second region (220) is located between the first region (210) and the third region (230). The second plate (20) has an inlet (202) and an outlet (203) communicating with the refrigerant cavity (200). The inlet (202) is located in the first region (210) and the outlet (203) is located in the third region (230). Multiple guide plates (60) are at least partially disposed in the first region (210), with one end disposed at the liquid inlet (202) and the other end extending toward the side where the liquid outlet (203) is located. Multiple guide plates (60) are at least partially disposed in the third region (230), with one end disposed at the liquid outlet (203) and the other end extending toward the side where the liquid inlet (202) is located. Multiple guide plates (60) are at least partially disposed in the second region (220) and are arranged in a fishbone shape.

9. The refrigerant heater according to any one of claims 1 to 8, characterized in that, It also includes a third plate (90), which is disposed on one side of the refrigerant heater in the first direction (X). The third plate (90) has a first port (901) and a second port (902), which are respectively connected to the refrigerant cavity (200). The first port (901) and the second port (902) are located diagonally opposite each other on the third plate (90). Alternatively, it may also include a third plate (90) and a fourth plate (91), wherein the third plate (90) is disposed on one side of the refrigerant heater in the first direction (X), and the fourth plate (91) is disposed on the other side of the refrigerant heater in the first direction (X). The third plate (90) is provided with a first opening (901), and the fourth plate (91) is provided with a second opening (902).

10. A direct cooling system for a power conversion device, characterized in that, include: The air-cooled heat exchanger (3), compressor (2), four-way valve (6), inner heat exchanger (4) and electronic expansion valve (5) are connected in series to form a direct cooling flow path (7). The direct cooling system of the power conversion device further includes a refrigerant heater (1) as described in any one of claims 1 to 9, wherein the refrigerant heater (1) is connected in series on the direct cooling flow path (7) and is located between the air-cooled heat exchanger (3) and the suction port of the compressor (2).

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