Power conversion device

Abstract

The utility model provides a power conversion device which comprises a shell, a circuit board, at least one relay, a first heat conduction plate and a first heat conduction pad, the first heat conduction plate, the first heat conduction pad, the circuit board and the at least one relay are all arranged in the shell, and the at least one relay and the first heat conduction pad are arranged on the same side of the circuit board. One end of the first heat-conducting plate is connected with the shell, and the other end is connected with one side, deviating from the circuit board, of the first heat-conducting pad. Heat generated by the relay is transmitted to the circuit board, the circuit board transmits the heat to the first heat conducting plate through the first heat conducting pad, and then the first heat conducting plate transmits the heat to the shell to be dissipated. According to the power conversion device, the shell serves as a radiator, the first heat conduction pad and the first heat conduction plate serve as heat dissipation paths of the relay, heat is conducted to the shell and then dissipated, the structure is simple, and the heat dissipation effect is good.

Description

Technical Field

[0001] This application relates to the technical field of heat dissipation devices, and particularly to a power conversion device. Background Art

[0002] As a key component in a power conversion device, a relay mainly functions for input / output protection, power-off recovery, and isolation control. As the number of relays increases, the amount of heat generated by them also increases. The relatively high heat is not conducive to the stable operation of the power conversion device. Therefore, it is necessary to dissipate heat from the relay. Conventionally, a heat sink is usually used to dissipate heat from a relay. The heat sink and the relay are respectively mounted on a circuit board through pins. The relay transfers heat to the circuit board through the pins, and the circuit board then transfers the heat to the heat sink. The heat sink can be in contact with the device housing through a thermal pad to dissipate the heat from the device housing. When there are a large number of relays on a single board, multiple heat sinks need to be added for heat dissipation, which not only occupies a large amount of space but also increases the manufacturing cost, and cannot effectively reduce the temperature of the entire device. Summary of the Utility Model

[0003] This application provides a power conversion device with a simple structure and good heat dissipation effect.

[0004] The power conversion device provided by this application includes a housing, a circuit board, at least one relay, a first heat conducting plate, and a first thermal pad. The first heat conducting plate, the first thermal pad, the circuit board, and at least one relay are all arranged inside the housing. At least one relay and the first thermal pad are arranged on the same side of the circuit board. One end of the first heat conducting plate is connected to the housing, and the other end of the first heat conducting plate is connected to the side of the first thermal pad facing away from the circuit board. The heat generated by the relay is transferred to the circuit board, and the circuit board then conducts the heat to the first heat conducting plate through the first thermal pad. The first heat conducting plate finally conducts the heat to the housing and dissipates it. The power conversion device of this application uses the housing as a radiator, and the first thermal pad and the first heat conducting plate as heat dissipation paths to conduct the heat of the relay to the housing and dissipate it, with a simple structure and good heat dissipation effect.

[0005] In one embodiment, at least one relay includes a plurality of relays, and the plurality of relays include a first relay and a second relay. The first relay and the second relay are respectively located on both sides of the first heat conducting plate along a first direction. The above-mentioned first direction is perpendicular to the thickness direction of the circuit board. The first heat conducting plate can isolate the first relay and the second relay, reducing the situation of thermal coupling between the two relays.

[0006] In one embodiment, one end of the first heat conducting plate is connected to the first inner surface of the housing. The power conversion device further includes a second heat conducting pad disposed between the first inner surface and at least one relay. The second heat conducting pad is configured to conduct the heat of the relay to the housing. The second heat conducting pad adds a heat dissipation path on the basis of the first heat conducting pad and the first heat conducting plate, improving the heat dissipation efficiency of the power conversion device.

[0007] In one embodiment, the second heat conducting pad covers the projection of at least one relay on the first inner surface, such that the contact area between the relay and the second heat conducting pad is relatively large, and the heat conducting effect is good, thereby improving the heat dissipation efficiency.

[0008] In one embodiment, the power conversion device further includes a second heat conducting plate disposed between the second heat conducting pad and the first inner surface and in contact with the first heat conducting plate. The second heat conducting plate can make the second heat conducting pad have a relatively thin thickness, so that the thermal resistance of the second heat conducting pad is relatively low and the heat conductivity is good.

[0009] In one embodiment, the housing includes a first side wall that is recessed into the housing to form a pit structure. The pit structure faces at least one relay, and the projection of the pit structure on the circuit board overlaps with the projection of at least one relay on the circuit board. The above-mentioned pit structure can make the second heat conducting pad have a relatively thin thickness, so that the thermal resistance of the second heat conducting pad is relatively low and the heat conductivity is good.

[0010] In one embodiment, the power conversion device further includes a third heat conducting pad disposed on the side of the circuit board facing away from the first heat conducting plate and in contact with the housing. The relay includes a body and pins. One end of the pin is connected to the body, and the other end is connected to and penetrates through the circuit board and is in contact with the third heat conducting pad. The third heat conducting pad forms a third heat dissipation path of the power conversion device. The relay conducts a part of the heat to the third heat conducting pad through the pins and then conducts it to the housing for heat dissipation. The combined heat dissipation of multiple heat dissipation paths makes the heat dissipation efficiency of the power conversion device relatively high.

[0011] In one embodiment, the power conversion device further includes a third heat conducting plate disposed on the side of the third heat conducting pad facing away from the circuit board and connected to the housing. The third heat conducting plate can make the third heat conducting pad have a relatively thin thickness, so that the thermal resistance of the third heat conducting pad is relatively low and the heat conductivity is good.

[0012] In one embodiment, the circuit board is provided with a plurality of first through holes, and the projection of the first heat conducting pad on the circuit board covers the plurality of first through holes. The first through holes, as the heat dissipation channels of the circuit board, can effectively reduce the junction temperature of the circuit board, and at the same time can also improve the temperature uniformity in the thickness direction of the circuit board, enabling the device to operate more stably.

[0013] In one embodiment, a first metal foil layer is provided between the circuit board and the first heat-conducting pad. The first metal foil layer has good thermal conductivity and can effectively transfer heat to the first heat-conducting pad, which is beneficial to improving the heat dissipation efficiency and making the device operate stably. The first metal foil layer has a plurality of second through-holes, and the positions of the plurality of second through-holes correspond to those of the plurality of first through-holes one by one. The first through-holes and the second through-holes communicate to form a heat dissipation channel, which can dissipate the heat inside the circuit board.

[0014] In one embodiment, a second metal foil layer is provided on the side of the circuit board facing away from the first heat-conducting pad. The second metal foil layer has good thermal conductivity, which is beneficial to the heat dissipation of the circuit board. The second metal foil layer has a plurality of third through-holes, and the positions of the plurality of third through-holes correspond to those of the plurality of first through-holes one by one. The first through-holes and the third through-holes communicate to form a heat dissipation channel, which can dissipate the heat inside the circuit board.

[0015] In one embodiment, a third metal foil layer is provided on the inner wall of the first through-hole. The third metal foil layer has good thermal conductivity, which is beneficial to improving the heat dissipation efficiency.

[0016] In one embodiment, the power conversion device further includes a bus bar, which is installed on the side of the circuit board facing the third heat-conducting pad. The bus bar is connected to the pin and the third heat-conducting pad. The bus bar can assist the third heat-conducting pad in heat conduction and improve the heat dissipation efficiency.

[0017] In one embodiment, the power conversion device further includes a plurality of fins, which are arranged on the outer wall of the housing close to the first heat-conducting plate. The arrangement of the fins increases the surface area of the housing in disguise, which is beneficial to improving the heat dissipation efficiency of the power conversion device.

[0018] In one embodiment, the housing includes a first housing and a second housing, and the first housing and the second housing are detachably connected. The circuit board, at least one relay, the first heat-conducting plate and the first heat-conducting pad are arranged in the second housing. When installing and maintaining the power conversion device, the first housing can be opened to assemble or maintain the components inside the housing, which is convenient for operation. Description of the Drawings

[0019] Figure 1 Schematic structural diagram of the power conversion device in an embodiment of the present application;

[0020] Figure 2 Schematic structural diagram of the power conversion device in another embodiment of the present application;

[0021] Figure 3 Schematic structural diagram of the first relay group, the second relay group, the circuit board and the first heat-conducting plate in an embodiment of the present application;

[0022] Figure 4Schematic structural diagram of a power conversion device in another embodiment of the present application;

[0023] Figure 5 Schematic structural diagram of a power conversion device in another embodiment of the present application;

[0024] Figure 6 Schematic structural diagram of a power conversion device in another embodiment of the present application;

[0025] Figure 7 Schematic structural diagram of a power conversion device in another embodiment of the present application;

[0026] Figure 8 Schematic structural diagram of a power conversion device in another embodiment of the present application;

[0027] Figure 9 Schematic structural diagram of a power conversion device in another embodiment of the present application.

[0028] Reference numerals:

[0029] 1 - housing; 2 - first heat conducting plate; 3 - first heat conducting pad; 4 - circuit board; 5 - relay; 51 - first relay; 52 - second relay; 501 - first relay group; 502 - second relay group; 510 - body; 511 - pin; 6 - second heat conducting pad; 11 - first inner surface; 7 - second heat conducting plate; 12 - pit structure; 8 - third heat conducting pad; 9 - third heat conducting plate; 13 - second inner surface; 41 - first through hole; 42 - first metal foil layer; 421 - second through hole; 43 - second metal foil layer; 431 - third through hole; 44 - third metal foil layer; 14 - first housing; 15 - second housing; 10 - fin. Detailed implementation manners

[0030] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in various forms and should not be construed as being limited to the embodiments described herein. The same reference numerals in the figures denote the same or similar structures, and thus their repeated description will be omitted. The words expressing positions and directions described in the embodiments of the present application are illustrative with reference to the accompanying drawings, but can be changed as needed, and all changes are included in the protection scope of the present application. The accompanying drawings of the embodiments of the present application are only used to illustrate the relative positional relationship, and they do not represent the actual proportions.

[0031] It should be noted that specific details are set forth in the following description to facilitate the understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0032] To facilitate the understanding of the power conversion device provided by the embodiments of the present application, the following first introduces its application scenarios.

[0033] The power conversion device may include a photovoltaic inverter, a photovoltaic optimizer, an uninterruptible power supply, etc. A relay is a key component on the circuit board of the power conversion device. With the vigorous development of the new energy industry, the output power of the power conversion device is gradually increasing, the number of relays is gradually increasing, and the heat generation is also increasing. The coil and contacts of the relay are encapsulated in the thermoplastic housing of the relay, and the heat generation is mainly concentrated in the coil and contacts. The heat dissipation of the relay is usually achieved by inserting a heat sink beside the relay, and the heat sink is arranged one-to-one with the relay. After each relay transfers the heat to the circuit board through the pins, it is then transferred to the corresponding heat sink for heat dissipation. When the number of relays is large and the density is high, the density of the heat sinks also increases, which will occupy a large space and increase the heat dissipation cost at the same time. In addition, the heat sinks usually adopt two structures, namely L-shaped and I-shaped. Among them, when using an L-shaped heat sink, a heat conductive pad is pasted on the heat sink and the heat conductive pad is connected to the device housing to transfer the heat to the housing for dissipation. For a power conversion device with a high relay density, a large number of heat sinks and heat conductive pads need to be installed, which is inconvenient for assembly. When using an I-shaped heat sink, the long teeth of the I-shaped heat sink make the heat dissipation area of the heat sink larger, and the I-shaped heat sink will radiate the obtained heat to the surrounding environment. The high-density heat sinks will cause heat accumulation, resulting in an increase in the temperature in the device. If a fan is added beside the I-shaped heat sink, although it can accelerate the air flow speed in the device and dissipate the accumulated heat, adding the fan will increase the additional heat dissipation cost and generate noise, affecting the performance of the device.

[0034] For the above reasons, the present application provides a power conversion device with a simple structure and good heat dissipation effect.

[0035] Figure 1 is a schematic structural diagram of the power conversion device in an embodiment of the present application, as Figure 1As shown, in one embodiment, the above power conversion device includes a housing 1, a circuit board 4, at least one relay 5, a first heat conducting plate 2, and a first heat conducting pad 3. The circuit board 4, at least one relay 5, the first heat conducting plate 2, and the first heat conducting pad 3 are all disposed within the housing 1. One end of the first heat conducting plate 2 is connected to the housing 1, and the other end is connected to the first heat conducting pad 3. The circuit board 4 carries at least one relay 5, and the relay 5 generates heat during operation, and the heat is transferred to the circuit board 4. The circuit board 4 conducts the heat to the first heat conducting plate 2 through the first heat conducting pad 3, and then the first heat conducting plate 2 conducts the heat to the housing 1 and dissipates it. The power conversion device of the present application uses the housing 1 as a radiator, and uses the first heat conducting pad 3 and the first heat conducting plate 2 as heat dissipation paths to conduct the heat of at least one relay 5 to the housing 1 and dissipate it. The structure is simple and the heat dissipation effect is good.

[0036] Figure 2 This is a schematic structural diagram of the power conversion device in another embodiment of the present application. As Figure 2 shown, in one embodiment, the above at least one relay 5 may include a plurality of relays 5. For example, taking the plurality of relays 5 including a first relay 51 and a second relay 52 as an example. The first relay 51 and the second relay 52 are respectively located on both sides of the first heat conducting plate 2 along the first direction N. The above first direction N is perpendicular to the thickness direction of the circuit board 4. Since the first relay 51 and the second relay 52 respectively generate heat, there is thermal coupling between them. The first heat conducting plate 2 is disposed between the first relay 51 and the second relay 52, and can isolate the two relays 5, reducing the situation of thermal coupling. When a plurality of relays 5 are provided, the plurality of relays 5 share one heat dissipation path to export heat, occupying less space and saving costs.

[0037] Figure 3 This is a schematic structural diagram of the first relay group, the second relay group, the circuit board, and the first heat conducting plate in one embodiment of the present application. As Figure 3 shown, in one embodiment, the above plurality of relays 5 may be grouped, for example, divided into a first relay group 501 and a second relay group 502. The first relay group 501 and the second relay group 502 are respectively located on both sides of the first heat conducting plate 2 along the first direction N. Among them, the first relay group 501 includes a plurality of first relays 51, and the second relay group 502 includes a plurality of second relays 52. The plurality of first relays 51 are arranged and installed along the second direction M, and the plurality of second relays 52 are also arranged and installed along the second direction M. The second direction M is parallel to the first heat conducting plate 2 and the second direction M is perpendicular to the first direction N. The first heat conducting plate 2 is located between the first relay group 501 and the second relay group 502, isolating the first relay group 501 and the second relay group 502, and reducing the thermal coupling between the two relay groups.

[0038] Figure 4 The structural schematic diagram of the power conversion device in another embodiment of the present application. As Figure 4 shown, in one embodiment, the above-mentioned relay 5 includes a body 510 and pins 511. One end of the pin 511 is connected to the body 510, and the other end is connected to and penetrates through the circuit board 4. The body 510 of the relay 5 includes a plastic shell and a coil and contacts (not shown in the figure) disposed within the plastic shell. The heat of the relay 5 is mainly generated by the coil and contacts. A part of the heat generated by the coil is transferred to the pin 511, and the other part of the heat is transferred to the plastic shell. The contacts are connected to the pin 511, and the relay 5 transfers heat to the circuit board 4 through the pin 511. One end of the above-mentioned first heat conducting plate 2 is connected to the first inner surface 11 of the housing 1. The power conversion device further includes a second heat conducting pad 6, and the second heat conducting pad 6 is disposed between the first inner surface 11 and at least one relay 5 for conducting the heat of the plastic shell of the body 510 to the housing 1.

[0039] In the above-mentioned some embodiments, on the one hand, the relay 5 transfers heat to the circuit board 4 through the pin 511, and then the circuit board 4 transfers the heat to the housing 1 through the first heat conducting plate 2 and the first heat conducting pad 3 and dissipates it. The first heat conducting plate 2 and the first heat conducting pad 3 form the first heat dissipation path of the power conversion device. On the other hand, the body 510 of the relay 5 is in contact with the second heat conducting pad 6, and the body of the relay 5 transfers the heat to the housing 1 through the second heat conducting pad 6 and dissipates it. The second heat conducting pad 6 forms the second heat dissipation path of the power conversion device. The above two heat dissipation paths are combined and arranged, and the heat dissipation effect is better. It should be noted that the above two heat dissipation paths can also be separately arranged according to the heat dissipation requirements.

[0040] In order to improve the heat conduction effect, the above-mentioned second heat conducting pad 6 can cover the projection of at least one relay 5 on the first inner surface 11, so that the contact area between the body 510 of the relay 5 and the second heat conducting pad 6 is relatively large, the heat conduction effect is good, and thus the heat dissipation efficiency is improved.

[0041] In addition to the relay 5 and the circuit board 4 in the power conversion device, other components are also provided. Since the sizes of the components are different, in order to accommodate all the components, the height of the housing 1 of the power conversion device needs to be high enough, which will make the distance between the first inner surface 11 and the body 510 of the relay 5 relatively far. To ensure that the second heat conducting pad 6 can be in contact with the body 510 of the relay 5, the thickness of the second heat conducting pad 6 needs to be increased, but increasing the thickness of the second heat conducting pad 6 will increase the thermal resistance and cause poor heat conduction. The height direction of the above-mentioned power conversion device is the same as the thickness direction of the circuit board 4.

[0042] Figure 5 The structural schematic diagram of the power conversion device in another embodiment of the present application. As Figure 5As shown in the figure, to solve the above problems, in one embodiment, the power conversion device may further include a second heat conducting plate 7. The second heat conducting plate 7 is disposed between the second heat conducting pad 6 and the first inner surface 11, and is in contact connection with the first heat conducting plate 2. The second heat conducting pad 6 conducts the heat generated by the body 510 of the relay 5 to the first heat conducting plate 2 and the second heat conducting plate 7, and then conducts the heat to the housing 1 through the first heat conducting plate 2 and the second heat conducting plate 7 and dissipates it. The second heat conducting plate 7 can still have a relatively thin thickness under the condition that the second heat conducting pad 6 is in contact with the body 510 of the relay 5, so that the second heat conducting pad 6 has a lower thermal resistance and better thermal conductivity.

[0043] If the distance between the body 510 of the relay 5 and the first surface is relatively far, increasing the thickness of the second heat conducting plate 7 will cause poor heat conduction of the second heat conducting plate 7. Figure 6 The following is a schematic structural diagram of the power conversion device in another embodiment of the present application. As Figure 6 shown, in another embodiment, the housing 1 includes a first side wall. The first side wall is recessed into the housing 1 to form a pit structure 12. The pit structure 12 faces at least one relay 5, and the projection of the pit structure 12 on the circuit board 4 overlaps with the projection of at least one relay 5 on the circuit board 4. The first inner surface 11 in this embodiment is the inner surface of the side of the pit structure 12 facing the inside of the housing 1. The second heat conducting pad 6 is disposed between the first inner surface 11 and the body 510 of the relay 5. The heat of the relay 5 is transferred to the pit structure 12 through the second heat conducting pad 6, and thus dissipates from the housing 1. The function of the pit structure 12 is the same as that of the second heat conducting plate 7 in the above embodiment, that is, it can still have a relatively thin thickness under the condition that the second heat conducting pad 6 is in contact with the body 510 of the relay 5, so that the second heat conducting pad 6 has a lower thermal resistance and better thermal conductivity. When preparing the housing 1, the pit structure 12 and the housing 1 can be integrally die-cast. The thickness of the plate body of the pit structure 12 is the same as the thickness of the housing 1, and the heat conduction effect is better.

[0044] Figure 7 The following is a schematic structural diagram of the power conversion device in another embodiment of the present application. As Figure 7 shown, in one embodiment, the power conversion device may further include a third heat conducting pad 8. The third heat conducting pad 8 is disposed on the side of the circuit board 4 facing away from the first heat conducting plate 2, and the third heat conducting pad 8 is in contact with the housing 1. The pin 511 of the relay 5 penetrates through the circuit board 4 and is in contact with the third heat conducting pad 8. The third heat conducting pad 8 forms the third heat dissipation path of the power conversion device. The relay 5 conducts a part of the heat to the housing 1 through the third heat conducting pad 8 through the pin 511 and dissipates it, and another part of the heat is led to the circuit board 4. The circuit board 4 then conducts the heat to the housing 1 through the first heat conducting pad 3 and the first heat conducting plate 2 and dissipates it.

[0045] Figure 8 FIG. 118 is a schematic structural diagram of a power conversion device according to another embodiment of the present application. As Figure 8 shown, in one embodiment, the power conversion device may further include a third heat conducting plate 9, which is disposed on the side of the third heat conducting pad 8 away from the circuit board 4 and is connected to the housing 1. The surface of the housing 1 in contact with the third heat conducting pad 8 is the second inner surface 13, that is, the third heat conducting plate 9 is located between the third heat conducting pad 8 and the second inner surface 13. The third heat conducting plate 9 has the same function as the second heat conducting plate 7. The relay 5 conducts heat to the third heat conducting plate 9 through the third heat conducting pad 8 via the pin 511, and the third heat conducting plate 9 then conducts the heat to the housing 1 for dissipation. The third heat conducting plate 9 enables the third heat conducting pad 8 to have a relatively thin thickness, so that the thermal resistance of the third heat conducting pad 8 is relatively low.

[0046] Figure 9 FIG. 120 is a schematic structural diagram of a power conversion device according to another embodiment of the present application. As Figure 9 shown, in one embodiment, to prevent the internal temperature of the circuit board 4 from rising rapidly, resulting in overheating of the circuit board 4 and unstable operation, the circuit board 4 may be provided with a plurality of first through holes 41, and the projection of the first heat conducting pad 3 on the circuit board 4 covers the plurality of first through holes 41. The first through holes 41 serve as thermal vias of the circuit board 4 and can effectively reduce the junction temperature of the circuit board 4. The junction temperature refers to the operating temperature inside the circuit board 4, which is usually higher than the temperature on the surface of the circuit board 4. The first through holes 41 can serve as heat dissipation channels to reduce the internal temperature of the circuit board 4, and the first through holes 41 can also improve the temperature uniformity in the thickness direction of the circuit board 4, enabling the power conversion device to operate more stably.

[0047] Please continue to refer to Figure 9 , to promote heat dissipation, in one embodiment, a first metal foil layer 42 may be provided between the circuit board 4 and the first heat conducting pad 3. The first metal foil layer 42 has a plurality of second through holes 421, and the positions of the plurality of second through holes 421 correspond to those of the plurality of first through holes 41 one by one. A second metal foil layer 43 is provided on the side of the circuit board 4 away from the first heat conducting pad 3. The second metal foil layer 43 has a plurality of third through holes 431, and the positions of the plurality of third through holes 431 correspond to those of the plurality of first through holes 41 one by one. A third metal foil layer 44 is also provided on the hole wall of the first through hole 41. The first metal foil layer 42, the second metal foil layer 43, and the third metal foil layer 44 may be copper foils. Copper foils have good thermal conductivity and can improve the heat dissipation efficiency of the circuit board 4. At the same time, the first through holes 41, the second through holes 421, and the third through holes 431 are interconnected to form a heat dissipation channel, which can effectively transfer the heat inside the circuit board 4 to the outside of the circuit board 4, enabling the circuit board 4 to operate stably.

[0048] In one embodiment, the power conversion device may further include a bus bar (not shown in the figure). The bus bar is mounted on the side of the circuit board 4 facing the third heat conducting pad 8. The bus bar is connected to the pin 511 and the third heat conducting pad 8, and is used to conduct the heat of the pin 511 to the third heat conducting pad 8, and then conduct it to the housing 1 to dissipate. The bus bar can assist the third heat conducting pad 8 in heat conduction, improving the heat dissipation efficiency.

[0049] Please continue to refer to Figure 9 , in one embodiment, the housing 1 includes a first housing 14 and a second housing 15. The first housing 14 and the second housing 15 are detachably connected. The first heat conducting plate 2, the first heat conducting pad 3, the circuit board 4 and at least one relay 5 are all arranged in the second housing 15. Among them, the circuit board 4 can be fixedly mounted on the second housing 15 through studs. When maintaining the power conversion device, the first housing 14 is opened to separate it from the second housing 15 for maintenance, which is convenient to operate.

[0050] The above-mentioned power conversion device further includes a plurality of fins 10. The plurality of fins 10 are arranged on the outer wall of the housing 1 close to the first heat conducting plate 2. The plurality of fins 10 are arranged at intervals in sequence. By arranging the plurality of fins 10, the surface area of the housing 1 is increased in a disguised form, which is beneficial to improving the heat dissipation efficiency of the power conversion device. Of course, the above-mentioned plurality of fins 10 can also be arranged on the outer wall of the entire housing 1, and the present application does not make specific restrictions.

[0051] Please continue to refer to Figure 9 , in one embodiment, the pit structure 12 is located in the second housing 15. Since the first heat conducting plate 2 is arranged on the first inner surface 11 of the pit structure 12, the heat at this position is relatively high. The above-mentioned fins 10 are arranged on the outer wall of the second housing 15, and the number of fins 10 located in the pit structure 12 can be greater than the number of fins 10 at other positions of the second housing 15, which is beneficial to improving the heat dissipation efficiency.

[0052] In a specific application scenario, the power conversion device includes six relays 5, and the size of each relay 5 is 2.2 cm * 1.6 cm * 2.1 cm. Every three relays 5 form a relay group and are arranged on the circuit board 4. The first heat conducting plate 2 is arranged between the two relay groups. In this application scenario, the power conversion device simultaneously includes the three heat dissipation paths in some of the above embodiments. When the power conversion device is in a low full-load working condition, for example, when the heat dissipation of each relay is 1.3 W, the maximum temperature gain of the plastic shell of the relay body 510 is 12.7 °C, the maximum temperature gain of the pin 511 is 15.8 °C, and the maximum temperature gain of the coil is 13.8 °C. The power conversion device uses the above three heat dissipation paths to dissipate heat from the relay 5, with a relatively high heat dissipation efficiency, effectively reducing the ambient temperature around the relay 5, reducing the baking of low-temperature specification components around the relay 5, and extending the service life of the power conversion device.

[0053] The terms used in the above embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and claims of the present application, the singular forms "a", "an", "the", "above", "said", "this" are intended to include, for example, the expression "one or more" as well, unless there is a clear contrary indication in the context.

[0054] Reference to "one embodiment" or "a specific embodiment" etc. described in this specification means that a specific feature, structure or characteristic described in connection with that embodiment is included in one or more embodiments of the present application. The terms "comprising", "including", "having" and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

Claims

1. A power conversion device, It is characterized in that The invention comprises a shell, a circuit board, at least one relay, a first heat-conducting plate and a first heat-conducting pad, wherein the first heat-conducting plate, the first heat-conducting pad, the circuit board and the at least one relay are all arranged in the shell, the at least one relay and the first heat-conducting pad are arranged on the same side of the circuit board, one end of the first heat-conducting plate is connected to the shell, and the other end of the first heat-conducting plate is connected to a side of the first heat-conducting pad away from the circuit board.

2. The power conversion device according to claim 1, It is characterized in that The at least one relay includes a plurality of relays, the plurality of relays include a first relay and a second relay, the first relay and the second relay are respectively located on both sides of the first heat conducting plate along a first direction, and the first direction is perpendicular to a thickness direction of the circuit board.

3. The power conversion device according to claim 1, It is characterized in that One end of the first heat conducting plate is connected to the first inner surface of the shell; The power conversion device further includes a second thermally conductive pad disposed between the first inner surface and the at least one relay.

4. The power conversion device according to claim 3, It is characterized in that The second thermally conductive pad covers a projection of the at least one relay on the first inner surface.

5. The power conversion device according to claim 3, It is characterized in that The power conversion device further includes a second heat conducting plate, which is disposed between the second heat conducting pad and the first inner surface and contacts the first heat conducting plate.

6. The power conversion device according to claim 3, It is characterized in that The housing includes a first side wall, which is recessed into the housing to form a pit structure. The pit structure faces the at least one relay, and a projection of the pit structure on the circuit board overlaps with a projection of the at least one relay on the circuit board.

7. The power conversion device according to any one of claims 1 to 6, It is characterized in that The power conversion device further includes a third heat-conducting pad, which is disposed on a side of the circuit board away from the first heat-conducting plate and in contact with the housing; The relay comprises a body and a pin, one end of the pin is connected to the body, and the other end of the pin is connected to and passes through the circuit board and contacts the third thermal pad.

8. The power conversion device according to claim 7, It is characterized in that The power conversion device further includes a third heat conducting plate, which is disposed on a side of the third heat conducting pad away from the circuit board and connected to the housing.

9. The power conversion device according to claim 1, It is characterized in that The circuit board is provided with a plurality of first through holes, and the projection of the first thermal conductive pad on the circuit board covers the plurality of first through holes.

10. The power conversion device according to claim 9, It is characterized in that A first metal foil layer is disposed between the circuit board and the first thermal pad. The first metal foil layer has a plurality of second through holes. The positions of the plurality of second through holes correspond one-to-one to the positions of the plurality of first through holes.

11. The power conversion device according to claim 9, characterized in that, a second metal foil layer is provided on a side of the circuit board facing away from the first heat conducting pad, the second metal foil layer has a plurality of third through holes, and positions of the plurality of third through holes correspond to positions of the plurality of first through holes one by one.

12. The power conversion device according to claim 9, characterized in that, a third metal foil layer is provided on a hole wall of the first through hole.

13. The power conversion device according to claim 7, characterized in that, the power conversion device further includes a bus bar, the bus bar is installed on a side of the circuit board facing the third heat conducting pad, and the bus bar is connected to the pin and the third heat conducting pad.

14. The power conversion device according to claim 1, characterized in that, the power conversion device further includes a plurality of fins, and the plurality of fins are arranged on an outer wall of the housing close to the first heat conducting plate.

15. The power conversion device according to claim 1, characterized in that, the housing includes a first housing and a second housing, the first housing and the second housing are detachably connected, and the circuit board, the at least one relay, the first heat conducting plate and the first heat conducting pad are arranged in the second housing.

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