Power conversion device

Abstract

The embodiment of the utility model provides power conversion equipment, and relates to the technical field of energy. The power conversion equipment comprises an equipment shell, a radiator, a power module and an insulating sheet, and the radiator is at least partially located outside the equipment shell or located in the equipment shell; the power module is used for converting direct current from a photovoltaic module or an energy storage battery into alternating current, the power module comprises a packaging shell, a first metal plate and a plurality of bare chips, the packaging shell is used for fixing the first metal plate and containing the bare chips, and the surface of one side of the first metal plate is located in the packaging shell and connected with the bare chips; the surface of the other side of the first metal plate is located outside the packaging shell and faces the radiator. The insulating sheet is fixed between the first metal plate and the radiator. According to the technical scheme, the heat in the power module is favorably diffused, the heat dissipation capability of the power module is improved, and the power conversion equipment can operate normally.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy, in particular to a power conversion device. BACKGROUND

[0002] The power conversion device is the core device of a photovoltaic system, and the power module inside the power conversion device is used to convert direct current from a photovoltaic module or an energy storage battery into alternating current. In the prior art, the die and the pin of the power module are both welded to the copper layer of a direct bonding copper (DBC) substrate, but the copper layer of the DBC is relatively thin, which is not conducive to the lateral diffusion of heat from the die, and the heat on the DBC is concentrated, thereby limiting the heat dissipation capacity of the power module and affecting the normal operation of the power conversion device. CONTENT OF THE UTILITY MODEL

[0003] The present application provides a power conversion device, which is conducive to the diffusion of heat in the power module, improves the heat dissipation capacity of the power module, and enables the power conversion device to operate normally.

[0004] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0005] The present application provides a power conversion device, which includes a device shell, a heat sink, a power module, and an insulating sheet. The heat sink is at least partially located outside the device shell, or the heat sink is located inside the device shell. The power module is used to convert direct current from a photovoltaic module or an energy storage battery into alternating current. The power module includes a packaging shell, a first metal plate, and a plurality of dies. The packaging shell is used to fix the first metal plate and accommodate the plurality of dies. The surface on one side of the first metal plate is located inside the packaging shell and connected to the plurality of dies. The surface on the other side of the first metal plate is located outside the packaging shell and faces the heat sink. The insulating sheet is fixed between the first metal plate and the heat sink.

[0006] Direct current from a photovoltaic module or an energy storage battery can be converted into alternating current by a power module of a power conversion device. The heat of the power module mainly comes from the die. Since the die is fixed on the first metal plate, the heat of the die can be transferred to the heat sink through the first metal plate, and the heat sink can dissipate heat for the die. The insulating sheet between the first metal plate and the heat sink can prevent the first metal plate from contacting the heat sink, reducing the risk of the heat sink being electrified and causing harm to users. Since the first metal plate can protrude from the inside of the package shell to the outside of the package shell, the first metal plate is thicker. Compared with the metal layer (copper layer) on the DBC in the prior art, the thicker first metal plate has stronger heat diffusion capacity. Not only can the heat of the die be transferred to the heat sink through the first metal plate, but also the heat of the die can be diffused laterally on the first metal plate (heat is transferred in a direction perpendicular to the thickness of the first metal plate). The heat of the die can be transferred to the position of the first metal plate where the die is not fixed, which is conducive to the diffusion of heat on the first metal plate, reduces the risk of heat concentrating at the position of the die, and is conducive to the heat dissipation of the power module, so that the power conversion device can operate normally.

[0007] In addition, in the case of failure of the power module, if an explosion occurs around the power module, the power conversion device may not be powered off in time, and a direct connection may occur between the heat sink and the power module. Since the heat sink is generally in an exposed state and users can directly contact it, the electrified heat sink is a great danger to users. In the present application, the first metal plate is thicker and has higher strength, and can withstand greater impact force in the case of failure and explosion of the die, reducing the risk of breakage of the insulating sheet and the safety hazard caused by the electrified heat sink.

[0008] In an optional embodiment, the power module further comprises a first pin, a part of the first pin is located in the package shell and fixed to the first metal plate, and the other part of the first pin protrudes out of the package shell.

[0009] The first pin is fixedly connected with the first metal plate. Through the first pin, current (for example, from a circuit board) outside the package shell can be conducted to the first metal plate, and similarly, current on the first metal plate can also be conducted to the outside of the package shell (for example, to the circuit board). Since the first pin is fixedly connected with the first metal plate, the amount of connecting lines (for example, bonding lines) in the package shell is reduced, and the steps of producing the power module are also reduced, which is conducive to the production and manufacture of the power module.

[0010] In an optional embodiment, the edge surface of the first metal plate connects the surfaces on both sides of the first metal plate, and the first pin is fixed to the edge surface of the first metal plate.

[0011] The first pin is fixed on the edge surface of the first metal plate, so that the first pin does not occupy the position of the surface of the first metal plate, the surface of the first metal plate has a larger area for mounting the die, and the first metal plate can mount more dies.

[0012] In an alternative embodiment, a part of the insulating sheet is located between the part of the first pin extending out of the package shell and the heat sink.

[0013] If the insulating sheet is not arranged between the first pin and the heat sink, in order to ensure the safety regulations, the insulation distance between the first pin and the heat sink can only rely on the height of the power module itself, which limits the development of the power module towards the direction of small size. In the present application, since a part of the insulating sheet is located between the first pin and the heat sink, the first pin and the heat sink are isolated by the insulating sheet, and the insulation distance is realized. The insulation distance does not need to be ensured by increasing the thickness of the package shell or increasing the distance between the pin and the heat sink, which reduces the possibility of increasing the volume of the power module due to safety regulations.

[0014] In an alternative embodiment, the power module further comprises a second metal plate and a first connecting line; the second metal plate is fixed to the package shell, and the second metal plate has a gap between the first metal plate; the surface of one side of the second metal plate is located in the package shell, and the surface of the other side of the second metal plate is located outside the package shell and connected to the insulating sheet; each die comprises a switch tube, the first pole of the switch tube is connected to the first metal plate, the second pole of the switch tube is away from the first metal plate, and the first connecting line connects the second pole of the switch tube and the second metal plate.

[0015] The gap between the second metal plate and the first metal plate insulates the second metal plate from the first metal plate, and in the case that the second metal plate and the first metal plate connect different poles of the switch tube (one connects the first pole and the other connects the second pole), the possibility of mutual conduction of the first pole and the second pole of the switch tube is reduced. In addition, the second metal plate is connected to the heat sink, so that the second metal plate can transfer the heat in the package shell to the heat sink, which is beneficial to the heat dissipation of the power module.

[0016] In an alternative embodiment, the power module further comprises a second pin, a part of the second pin is located in the package shell and fixed to the second metal plate, and the other part of the second pin extends out of the package shell.

[0017] The second pin is fixedly connected with the second metal plate, and the current outside the packaging shell can be conducted to the second metal plate through the second pin. Similarly, the current on the second metal plate can also be conducted to the outside of the packaging shell through the second pin. Since the second pin is fixedly connected with the second metal plate, the amount of connection lines inside the packaging shell is reduced, and the steps of producing the power module are also reduced, which is beneficial to the production and manufacturing of the power module. In addition, in the case that the current flowing through the second pole is large, the second metal plate serves as a plate-shaped structure, and more pins can be connected thereon to match the current demand.

[0018] In an optional embodiment, the edge surface of the second metal plate is connected with the surfaces on both sides of the second metal plate, and the second pin is fixed to the edge surface of the second metal plate.

[0019] Fixing the second pin on the edge surface of the second metal plate is beneficial to the integral molding of the second pin and the second metal plate, and the step of welding the second pin on the second metal plate is saved, which is convenient for the production and manufacturing of the power module.

[0020] In an optional embodiment, the surface of the second metal plate outside the packaging shell is flush with the surface of the first metal plate outside the packaging shell.

[0021] Through the above design, the surface of the first metal plate outside the packaging shell is flush with the surface of the second metal plate outside the packaging shell, which is beneficial to the connection of the first metal plate and the second metal plate with the heat sink together, and reduces the possibility that any one of the first metal plate and the second metal plate is insufficiently connected with the heat sink.

[0022] In an optional embodiment, the power module further comprises a third pin and a second connection line; the third pin is fixed to the packaging shell, a part of the third pin is located inside the packaging shell and has a gap with the first metal plate, and another part of the third pin extends to the outside of the packaging shell; the control electrode of the switch tube faces away from the first metal plate, and the second connection line is located inside the packaging shell and connects the third pin and the control electrode of the switch tube.

[0023] The gap between the third pin and the first metal plate insulates the third pin from the first metal plate. The third pin is connected with the control electrode of the switch tube as an independent pin, and since the current flowing through the control electrode is usually small, the independent third pin can meet the current demand, and there is no need to set an independent metal plate to be connected with the control electrode (the independent metal plate can be connected with multiple pins, and has a larger current capacity), thereby reducing the cost and the size of the power module.

[0024] In an optional embodiment, the third pin is located on the side of the first metal plate facing away from the first pin.

[0025] The first pin and the third pin are arranged on different sides of the first metal plate, and the first pin is far away from the second pin, so that the conduction between the first pin and the second pin is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A schematic diagram of an overall structure of a light storage system is provided for the embodiment of the present application.

[0027] Figure 2 A schematic diagram of a structure of a power conversion device is provided for the embodiment of the present application.

[0028] Figure 3 A schematic diagram of a structure of a heat sink is provided for the embodiment of the present application.

[0029] Figure 4 A schematic diagram of a structure of another heat sink is provided for the embodiment of the present application.

[0030] Figure 5 A schematic diagram of a structure of still another heat sink is provided for the embodiment of the present application.

[0031] Figure 6 A topology diagram of a power conversion device is provided for the embodiment of the present application.

[0032] Figure 7 A schematic diagram of a structure of a power module is provided for the embodiment of the present application.

[0033] Figure 8 A schematic diagram of a structure of a first metal plate is provided for the embodiment of the present application.

[0034] Figure 9 A schematic diagram of a structure of a die is provided for the embodiment of the present application.

[0035] Figure 10 A schematic diagram of a structure of an insulating sheet is provided for the embodiment of the present application.

[0036] Figure 11 A schematic diagram of a structure of a first pin is provided for the embodiment of the present application.

[0037] Figure 12 A schematic diagram of a structure of a first electrode is provided for the embodiment of the present application.

[0038] Figure 13 A schematic diagram of a structure of a second metal plate is provided for the embodiment of the present application.

[0039] Figure 14 A schematic diagram of a structure of another insulating sheet is provided for the embodiment of the present application.

[0040] REFERENCE SIGNS:

[0041] 100 - light storage system; 10 - photovoltaic module; 20 - power conversion device; 201 - photovoltaic inverter; 202 - energy storage converter; 203 - DC-DC conversion circuit; 204 - DC-AC conversion circuit; 30 - box substation; 40 - booster station; 50 - power grid; 60 - energy storage battery; 1 - device shell; 11 - through hole; 2 - circuit board; 3 - power module; 31 - packaging shell; 311 - first side; 312 - second side; 32 - first metal plate; 33 - die; 331 - switch tube; 3311 - first pole; 3312 - second pole; 3313 - control pole; 34 - first pin; 35 - second metal plate; 36 - first connecting line; 37 - second pin; 38 - third pin; 39 - second connecting line; 310 - third connecting line; 4 - heat sink; 41 - heat conduction plate; 42 - fin; 43 - heat dissipation channel; 5 - heat shield; 51 - air inlet; 6 - insulating sheet. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all embodiments.

[0043] In the drawings of the embodiments of the present application, the entity structures of components, assemblies, etc. are represented by guide lines; structures composed of multiple components are represented by guide lines with brackets or solid arrows; hollow structures such as openings, holes, spaces, cavities, etc. are represented by guide lines with hollow arrows.

[0044] Figure 1 An exemplary structure of a light storage system 100 (solar photovoltaic energy storage power generation system) is shown, which includes a photovoltaic system and an energy storage system. Referring to Figure 1 In the photovoltaic system, the photovoltaic module 10 directly converts solar energy into electrical energy using the photovoltaic effect, wherein the photovoltaic module 10 usually includes multiple cell pieces in series or parallel to achieve a certain output power. The photovoltaic inverter 201 is used to convert the direct current from the photovoltaic module 10 into alternating current, which is sent to the box substation 30 corresponding to the photovoltaic inverter 201 after passing through the switch box, and the box substation 30 corresponding to the photovoltaic inverter 201 can convert the low-voltage alternating current output by the photovoltaic inverter 201 into medium-voltage alternating current, then deliver the alternating current to the booster station 40 and transmit it to the power grid 50 or other loads.

[0045] Referring to Figure 1In the energy storage system, the energy storage battery 60 can store unstable electric energy, and convert the direct current into alternating current through the energy storage converter 202 (Power Conversion System, PCS), and then transmit the stable electric energy to the power grid 50 or other loads after passing through the box-type substation 30 corresponding to the energy storage battery 60. In addition, through the energy storage converter 202, the alternating current of the power grid 50 can also be converted into direct current to charge the energy storage battery 60, and then store the electric energy in the energy storage battery 60.

[0046] The embodiment of the present application provides a power conversion device 20, Figure 2 The embodiment of the present application provides a power conversion device 20, Figure 1 The embodiment of the present application provides a power conversion device 20,

[0047] In another embodiment, the power conversion device 20 can be an energy storage converter 202 (see Figure 1 In this embodiment, the power conversion device 20 (energy storage converter 202) is used in the energy storage system, and the power conversion device 20 (energy storage converter 202) is used to convert the direct current from the energy storage battery 60 into alternating current and output to the power grid 50 or other loads. In addition, the power conversion device 20 (energy storage converter 202) can also convert the alternating current of the power grid 50 into direct current to charge the energy storage battery 60.

[0048] Figure 3 The embodiment of the present application provides a power conversion device 20, Figure 2 The embodiment of the present application provides a power conversion device 20, Figure 2 And Figure 3 The power conversion device 20 includes a device shell 1, a circuit board 2 and a power module 3. The device shell 1 can be any suitable housing or device box, and the present application does not limit it. The device shell 1 has a space for placing devices and devices inside, the circuit board 2 can be a printed circuit board (PCB), the circuit board 2 is fixed in the internal space of the device shell 1, and the power module 3 is located in the device shell 1 and fixed on the circuit board 2. That is, the circuit board 2 and the power module 3 are located in the device shell 1. The power module 3 is used to convert the direct current from the photovoltaic module 10 or the energy storage battery 60 into alternating current.

[0049] In order to dissipate heat from the power module 3, the power conversion device 20 further comprises a heat sink 4, wherein, Figure 3 A structure of the heat sink 4 is shown in FIG. 2, and Figure 3 In the embodiment shown, the heat sink 4 is an air-cooled heat sink, and the heat sink 4 comprises a heat-conducting plate 41 and a plurality of fins 42, the heat-conducting plate 41 is located inside the device shell 1 and is used to connect with the power module 3, the plurality of fins 42 are fixed on a surface of the heat-conducting plate 41 which is away from the power module 3, and there is a gap between two adjacent fins 42. The device shell 1 is provided with a through opening 11, and the plurality of fins 42 extend out of the device shell 1 through the through opening 11.

[0050] In other embodiments, the heat-conducting plate 41 and the plurality of fins 42 of the heat sink 4 are both located outside the device shell 1, and in such embodiments, the power module 3 extends into the through opening 11 of the device shell 1 to connect with the heat-conducting plate 41.

[0051] In the case where the heat sink 4 is an air-cooled heat sink, heat of the power module 3 can be transferred to the heat-conducting plate 41, and then transferred to the fins 42 through the heat-conducting plate 41, and heat on the fins 42 is exchanged with air to dissipate heat for the power module 3. In addition, in some embodiments, referring to Figure 2 and Figure 3 The power conversion device 20 can further comprise a heat dissipation cover 5, the heat dissipation cover 5 is located outside the device shell 1 and is fixed on the device shell 1, and the heat dissipation cover 5 can cover the plurality of fins 42 of the heat sink 4, and in order to facilitate heat dissipation, the heat dissipation cover 5 is further provided with a plurality of air inlets 51, for example, a plurality of air inlets and a plurality of air outlets.

[0052] In other embodiments, a part of the heat sink 4 is integrally formed with a part of the device shell 1, for example, Figure 4 Another structure of the heat sink 4 is shown in FIG. 3, and referring to Figure 4 The heat-conducting plate 41 of the heat sink 4 is integrally arranged with the device shell 1, that is, the heat-conducting plate 41 and the device shell 1 jointly constitute a structure surrounding the power module 3, and the plurality of fins 42 are located outside the device shell 1 and are fixed on the heat-conducting plate 41.

[0053] In other embodiments, the heat sink 4 can also be a liquid-cooled heat sink, Figure 5 Another structure of the heat sink 4 is shown in FIG. 4, and referring to Figure 5In the embodiment, the heat sink 4 is located in the device shell 1 and fixed on the power module 3, that is, the heat sink 4 does not protrude out of the device shell 1. The heat sink 4 is formed with a heat dissipation flow channel 43, which can allow a cooling liquid (for example, a water-based cooling medium) to flow. In the case that the heat sink 4 is a liquid cooling heat sink, the heat of the power module 3 can be transferred to the heat sink 4, and the cooling liquid can take away the heat of the power module 3 during the flow through the heat dissipation flow channel 43, thereby achieving liquid cooling of the power module 3.

[0054] The power module 3 can be provided with one or multiple, and each power module 3 is fixed on the circuit board 2 and electrically connected to the circuit board 2. In the case that the power module 3 is provided with multiple, one heat sink 4 can be connected to multiple power modules 3 at the same time and simultaneously dissipate heat for the multiple power modules 3. Alternatively, in the case that the power module 3 is provided with multiple, the heat sink 4 can also be provided with multiple, and each heat sink 4 dissipates heat for a corresponding heat sink 4. The number of power modules 3 and the number of heat sinks 4 are not specifically limited in the present application.

[0055] The power module 3 can be any device capable of converting one of alternating current and direct current into the other, Figure 6 An exemplary topological diagram of a power conversion device 20 is shown, referring to Figure 6 The power conversion device 20 includes multiple direct current-direct current conversion circuits 203 (DC-DC circuits) and a direct current-alternating current conversion circuit 204 (DC-AC circuit). The multiple direct current-direct current conversion circuits 203 are all boost circuits, and the direct current-alternating current conversion circuit 204 is a three-phase inverter circuit. The power module 3 is encapsulated with multiple switching tubes 331, for example, Figure 6 The multiple switching tubes 331 in the dashed box a in the middle can be encapsulated in one power module 3, which is not specifically limited in the present application.

[0056] Figure 7 An exemplary structure of a power module 3 is shown, referring to Figure 7 The power module 3 includes an encapsulation shell 31 and a first metal plate 32, and the encapsulation shell 31 is used to fix the first metal plate 32, for example, the encapsulation shell 31 is fixedly connected with the first metal plate 32 after solidification. The first metal plate 32 protrudes from the encapsulation shell 31 to the outside of the encapsulation shell 31, Figure 8 An exemplary structure of a first metal plate 32 is shown, referring to Figure 7 and Figure 8, the surface (M1) of one side of the first metal plate 32 is located inside the package shell 31, and the surface (M2) of the other side of the first metal plate 32 is located outside the package shell 31. It can be understood that the thickness of the first metal plate 32 is thicker than the metal layer (copper clad layer) on the copper clad ceramic substrate (DBC). The first metal plate 32 can be a copper plate or other plate-shaped structure capable of conducting heat, and the present application does not make specific limitations thereto.

[0057] Referring to Figure 8 , the surface (M2) of one side of the first metal plate 32 is located outside the package shell 31, wherein the surface (M2) of the first metal plate 32 can be flush with the surface of the package shell 31 facing the heat sink 4, or the surface (M2) of the first metal plate 32 can protrude from the surface of the package shell 31 facing the heat sink 4.

[0058] In addition, the power module 3 further comprises a plurality of dies 33 (two or more), Figure 9 An exemplary structure of a die 33 is shown, and the plurality of dies 33 are fixed to the surface (M1) of the first metal plate 32 inside the shell. Each die 33 comprises at least one switching tube 331, which can be an insulated gate bipolar transistor (IGBT) or a metal-oxide semiconductor field effect transistor (MOSFET). Each switching tube 331 comprises a control electrode, a first electrode and a second electrode, for example, in the case of an insulated gate bipolar transistor (IGBT), the first electrode of the switching tube 331 is the collector (C electrode), the second electrode of the switching tube 331 is the emitter (E electrode), and the control electrode of the switching tube 331 is the base (B electrode); for another example, in the case of a metal-oxide semiconductor field effect transistor (MOSFET), the first electrode of the switching tube 331 is the drain (D electrode), the second electrode of the switching tube 331 is the source (S electrode), and the control electrode of the switching tube 331 is the gate (G electrode).

[0059] In Figure 9 In the embodiment shown, two dies 33 are fixed on the first metal plate 32, and in other embodiments, three or four dies 33 are fixed on the first metal plate 32, and the present application does not make specific limitations thereto, as long as the number of dies 33 on the first metal plate 32 is more than one. Figure 8 and Figure 9 After the package shell 31 is packaged, the plurality of dies 33 are packaged inside the package shell 31.

[0060] After the power module 3 is installed on the circuit board 2, the surface (M2) of the first metal plate 32 outside the package 31 faces the heat sink 4. Since the first metal plate 32 is charged, if it comes into direct contact with the heat sink 4, it may cause a direct connection between the heat sink 4 and the power module 3. Since the heat sink 4 is generally exposed, users can directly contact it. Therefore, the charged heat sink 4 is a huge danger to users and may cause them harm.

[0061] Therefore, in this application, the power conversion device 20 also includes an insulating sheet 6. Figure 10 An exemplary structure of an insulating sheet 6 is shown, with reference to Figure 10 An insulating sheet 6 is fixed between the first metal plate 32 and the heat sink 4. For example, the insulating sheet 6 is a ceramic sheet, sintered (or fixed by bonding) onto the heat sink 4; or, for example, a plastic sheet or other insulating sheet structure, bonded or bolted to the heat sink 4. The first metal plate 32 connects to the insulating sheet 6, for example, by bonding the insulating sheet 6 to the first metal plate 32 with thermally conductive adhesive; or, for example, by contacting or pressing against the insulating sheet 6. The insulating sheet 6 located between the first metal plate 32 and the heat sink 4 prevents the first metal plate 32 from contacting the heat sink 4, reducing the risk of the heat sink 4 becoming electrified and causing harm to the user.

[0062] Among them, reference Figure 10 The heat generated by the power module 3 mainly comes from the die 33. Since the die 33 is fixed to the first metal plate 32, the heat from the die 33 can be transferred to the heat sink 4 through the first metal plate 32 and the insulating sheet 6, and then dissipated by the heat sink 4. Therefore, the thicker first metal plate 32 has a stronger heat dissipation capability than the metal layer (copper cladding) on ​​the DBC. It can not only transfer the heat from the die 33 to the heat sink 4 through the first metal plate 32, but also allow the heat from the die 33 to diffuse laterally on the first metal plate 32 (heat is transferred in a direction perpendicular to the thickness of the first metal plate 32). This allows the heat from the die 33 to be transferred to the positions on the first metal plate 32 where the die 33 is not fixed, which is beneficial for the diffusion of heat on the first metal plate 32, reduces the risk of heat concentration at the location of the die 33, and is conducive to the efficient heat dissipation of the power module 3.

[0063] Furthermore, in the event of a failure of the power module 3, if an explosion occurs centered on the power module 3 and the power conversion device 20 is not powered off in time, the heat sink 4 and the power module 3 may become directly connected. In this application, the first metal plate 32 is thicker and has higher strength, and can withstand greater impact force in the event of a failure and explosion of the power module 3, reducing the risk of the insulating sheet 6 breaking. This allows the insulating sheet 6 to continue to provide insulation after the power module 3 explodes, reducing the safety hazards caused by the energized heat sink 4 or the device housing 1.

[0064] In some embodiments, to facilitate connection between the power module 3 and the circuit board 2, the power module 3 further includes a first pin 34. Figure 11 An exemplary structure of the first pin 34 is shown. Figure 12 An exemplary internal structure of a power module 3 is shown, with reference to... Figure 11 and Figure 12 A portion of the first pin 34 is located inside the package housing 31 and fixed to the first metal plate 32, while another portion of the first pin 34 extends outside the package housing 31, serving as an auxiliary reference. Figure 10 The portion of the first pin 34 extending outside the package housing 31 is connected to the circuit board 2 (e.g., plugged into the circuit board 2). Since the first pin 34 is fixed to the first metal plate 32 (e.g., soldered or integrally connected), current outside the package housing 31 (e.g., current from the circuit board 2) can be conducted to the first metal plate 32 through the first pin 34. Similarly, current on the first metal plate 32 can also be conducted to the outside of the package housing 31 (e.g., to the circuit board 2) through the first pin 34. In this embodiment, because the first pin 34 is directly fixedly connected to the first metal plate 32, the amount of connecting wires (e.g., bonding wires) used inside the package housing 31 is reduced, and the steps in producing the power module 3 are also reduced, which is beneficial for the manufacturing of the power module 3.

[0065] In some other embodiments, the first pin 34 may also have a gap with the first metal plate 32, and the first pin 34 is electrically connected to the first metal plate 32 through a connecting wire.

[0066] With the first pin 34 fixed to the first metal plate 32, the first pin 34 can be fixed at any suitable location on the first metal plate 32. In one embodiment, refer to... Figure 11 The first metal plate 32 has an edge surface (M3), and a first pin 34 is fixed to the edge surface (M3) of the first metal plate 32. For example, the first pin 34 is soldered to the edge surface of the first metal plate 32, or the first pin 34 is integrally connected to the first metal plate 32, so that the first pin 34 extends from the edge surface of the first metal plate 32. The edge surface (M3) of the first metal plate 32 is the surface formed by the outer peripheral edge of the first metal plate 32. One side of the edge surface (M3) of the first metal plate 32 is connected to the surface (M1) of the first metal plate 32, and the other side is connected to the surface (M2) of the first metal plate 32. By fixing the first pin 34 to the edge surface (M3) of the first metal plate 32, the first pin 34 does not occupy the position of the surface (M1) of the first metal plate 32, thus providing a larger area on the surface (M1) of the first metal plate 32 for mounting the die 33, allowing the first metal plate 32 to mount more dies 33.

[0067] In addition, if the first pin 34 is fixed on the edge surface (M3) of the first metal plate 32, it is also beneficial to the integral molding of the first pin 34 and the first metal plate 32, which saves the step of welding the first pin 34 on the first metal plate 32, and facilitates the production and manufacturing of the power module 3.

[0068] In the case where the power module 3 includes the first pin 34, if no insulating sheet 6 is arranged between the first pin 34 and the heat sink 4, the insulation distance between the first pin 34 and the heat sink 4 can only rely on the height of the power module 3 itself, that is, the thickness of the packaging shell 31 needs to be increased, which limits the development of the power module 3 towards miniaturization in volume. Therefore, in the present application, referring back to Figure 10 , a part of the insulating sheet 6 (for example, the part within the dashed box K1) is located between the part of the first pin 34 that extends out of the packaging shell 31 and the heat sink 4. Since a part of the insulating sheet 6 is located between the first pin 34 and the heat sink 4, the first pin 34 and the heat sink 4 are isolated by the insulating sheet 6, which realizes the mutual insulation of the first pin 34 and the heat sink 4, so that it is not necessary to increase the thickness of the packaging shell 31 or increase the distance between the first pin 34 and the heat sink 4 to ensure the insulation distance, thereby reducing the possibility of increasing the volume of the power module 3 due to the problem of safety regulations.

[0069] Continuing to refer to Figure 12 , the die 33 is fixed on the first metal plate 32, which can make the first pole of the switch tube 331 included in the die 33 connected to the first metal plate 32. Figure 12 An exemplary structure of a first pole 3311 is shown, referring to Figure 12 , the first pole 3311 of the switch tube 331 contacts or is connected to the first metal plate 32, the second pole 3312 of the switch tube 331 faces away from the first metal plate 32, and the second pole 3312 of the switch tube 331 can be connected to other metal plates.

[0070] For example, the power module 3 further includes a second metal plate 35 and a first connecting line 36, Figure 13 An exemplary structure of a second metal plate 35 is shown, referring to Figure 13 , the second metal plate 35 is fixed to the packaging shell 31, for example, the packaging shell 31 is fixedly connected to the first metal plate 32 in the process of solidification. And the second metal plate 35 has a gap with the first metal plate 32, for example, the gap between the second metal plate 35 and the first metal plate 32 is filled with the material of the packaging shell 31, so that the second metal plate 35 and the first metal plate 32 are mutually insulated. The first connecting line 36 connects the second metal plate 35 and the second pole 3312 of at least one switch tube 331.

[0071] For example, in Figure 13In the illustrated embodiment, one of the dies 33 includes a plurality of switching tubes 331 (for example, two switching tubes 331), for auxiliary reference Figure 12 In the die 33, the two switching tubes 331 share a first pole 3311, and the first pole 3311 is connected to the first metal plate 32. For auxiliary reference Figure 13 The second poles 3312 of the two switching tubes 331 each face away from the first metal plate 32, the second poles 3312 of the plurality of switching tubes 331 are connected in series with each other (for example, connected by the third connecting line 310), and the first connecting line 36 connects the second metal plate 35 and the second pole 3312 of one of the switching tubes 331. The second metal plate 35 and the first metal plate 32 are connected to different poles of the switching tube 331 (one is connected to the first pole 3311, and the other is connected to the second pole 3312), which reduces the possibility of the first pole 3311 and the second pole 3312 of the switching tube 331 being conductive to each other.

[0072] In addition, in order to further improve the heat dissipation capability of the power module 3, one side of the surface (M4) of the second metal plate 35 is located inside the packaging shell 31, for auxiliary reference Figure 7 The other side of the surface (M5) of the second metal plate 35 is located outside the packaging shell 31. Among them, for auxiliary reference Figure 7 and Figure 10 After the power module 3 is installed on the circuit board 2, the surface (M5) of the second metal plate 35 located outside the packaging shell 31 is used to connect the insulating sheet 6, wherein the surface (M5) of the second metal plate 35 can be flush with the surface of the packaging shell 31 facing the heat sink 4, or the surface (M5) of the second metal plate 35 can protrude from the surface of the packaging shell 31 facing the heat sink 4. By connecting the second metal plate 35 with the heat sink 4, the second metal plate 35 can transfer the heat inside the packaging shell 31 to the heat sink 4, which is conducive to the heat dissipation of the power module 3.

[0073] In some embodiments, when the power module 3 includes the second pin 37, for auxiliary reference Figure 7 The surface (M5) of the second metal plate 35 located outside the packaging shell 31 is flush with the surface (M2) of the first metal plate 32 located outside the packaging shell 31. In this way, it is conducive to the connection of the first metal plate 32 and the second metal plate 35 with the heat sink 4, and reduces the possibility that one of the first metal plate 32 and the second metal plate 35 is insufficiently connected with the heat sink 4. It should be noted that "flush" here does not mean absolute flush, but in the direction from the circuit board 2 to the heat sink 4 (the thickness direction of the packaging shell 31), the spacing between the surface (M2) of the first metal plate 32 located outside the packaging shell 31 and the surface (M5) of the second metal plate 35 located outside the packaging shell 31 is less than or equal to 3 cm.

[0074] In addition, the second metal plate 35 is in a plate shape, and more pins can be connected thereto when the current flowing through the second pole 3312 is large, so as to match the current flowing demand.

[0075] In some embodiments, referring to Figure 13 , the power module 3 further comprises second pins 37, a part of the second pins 37 is located in the package shell 31 and fixed to the second metal plate 35, and the other part of the second pins 37 extends out of the package shell 31. The second pins 37 are fixedly connected with the second metal plate 35, and the current outside the package shell 31 can be conducted to the second metal plate 35 through the second pins 37, and the current on the second metal plate 35 can also be conducted to the outside of the package shell 31 through the second pins 37. In this embodiment, since the second pins 37 are fixedly connected with the second metal plate 35, the amount of connection lines in the package shell 31 is reduced, and the steps of producing the power module 3 are also reduced, which is beneficial to the production of the power module 3.

[0076] In other embodiments, the second pins 37 can have a gap with the second metal plate 35, and the second pins 37 are electrically connected with the second metal plate 35 through connection lines.

[0077] In Figure 13 the illustrated embodiment, the first pins 34 and the second pins 37 extend out of the package shell 31 from the same side of the package shell 31, for example, the package shell 31 has opposite first and second sides 311 and 312, and the first pins 34 and the second pins 37 extend out of the package shell 31 from the first side 311 of the package shell 31. In other embodiments, the first pins 34 and the second pins 37 extend out of the package shell 31 from different sides of the package shell 31, for example, the first pins 34 extend out of the package shell 31 from the first side 311 of the package shell 31, and the second pins 37 extend out of the package shell 31 from the second side 312 of the package shell 31.

[0078] In the case where the second pins 37 are fixed to the first metal plate 32, the second pins 37 can be fixed to any suitable position of the first metal plate 32. For example, referring back to Figure 11 , the second pins 37 are fixed to the edge surface (M6) of the second metal plate 35, wherein the second pins 37 can be welded with the edge surface (M6) of the second metal plate 35, or the second pins 37 can be integrally connected with the second metal plate 35, so that the second pins 37 are led out from the edge surface of the second metal plate 35.

[0079] It should be noted that the edge surface (M6) of the second metal plate 35 connects the surfaces on both sides of the second metal plate 35, that is, one side of the edge surface (M6) of the second metal plate 35 is connected to the surface (M4) of the second metal plate 35, and the other side of the edge surface (M6) of the second metal plate 35 is connected to the surface (M5) of the first metal plate 32. In this way, the second pin 37 is fixed to the edge surface of the second metal plate 35, which facilitates the one-piece forming of the second pin 37 and the second metal plate 35, eliminates the step of welding the second pin 37 to the second metal plate 35, and facilitates the production and manufacturing of the power module 3.

[0080] In addition, with reference to Figure 12 , the switch tube 331 also has a control electrode 3313, the control electrode 3313 of the switch tube 331 faces away from the first metal plate 32, and the control electrode 3313 of the switch tube 331 can be connected to other pins. In an embodiment, with reference to Figure 12 and Figure 13 , the power module 3 further includes a third pin 38 and a second connecting line 39, a part of the third pin 38 is located in the package shell 31 and has a gap with the first metal plate 32, so that the third pin 38 is insulated from the first metal plate 32, and the other part of the third pin 38 extends out of the package shell 31, wherein the third pin 38 is fixed to the package shell 31. The second connecting line 39 is located in the package shell 31 and connects the third pin 38 and the control electrode 3313 of at least one switch tube 331, for example, in the embodiment shown in Figure 13 , the two switch tubes 331 of the die 33 share a control electrode 3313, which is connected to the third pin 38 through the second connecting line 39. In this embodiment, the third pin 38 is used as an independent pin to connect the control electrode 3313 of the die 33. Since the current flowing through the control electrode 3313 is usually small, the current flowing through the independent third pin 38 can meet the current requirement, and there is no need to provide a separate metal plate to connect the control electrode 3313 of the die 33 (the separate metal plate can be connected to multiple pins and has a larger current capacity), thereby reducing the cost and size of the power module 3.

[0081] In other embodiments, the power module 3 further includes a third metal plate, a third pin 38, and a second connecting line 39, the third metal plate is fixed to the package shell 31, one side surface of the third metal plate is located in the package shell 31, and the other side surface of the third metal plate is located outside the package shell 31, the second connecting line 39 connects the control electrode 3313 of the switch tube 331 and the third metal plate, a part of the third pin 38 is located in the package shell 31 and is fixed to the third metal plate, and the other part of the third pin 38 extends out of the package shell 31,

[0082] In the case where the power module 3 includes the first pin 34 and the third pin 38, with reference to Figure 13For example, the first pin 34 extends out of the package shell 31 from a first side 311 of the package shell 31, and the third pin 38 extends out of the package shell 31 from a second side 312 of the package shell 31. In this way, the first pin 34 and the third pin 38 are arranged on different sides of the first metal plate 32, so that the first pin 34 is far away from the second pin 37, and the possibility of conduction between the first pin 34 and the second pin 37 is reduced. In other embodiments, the first pin 34 and the second pin 37 both extend out of the package shell 31 from the same side of the package shell 31. For example, the first pin 34 and the second pin 37 both extend out of the package shell 31 from the first side 311 of the package shell 31. For another example, the first pin 34 and the second pin 37 both extend out of the package shell 31 from the second side 312 of the package shell 31.

[0083] In some embodiments, referring back to Figure 10 , a part of the insulating sheet 6 (for example, the part within the dashed box K2) is located between the part of the third pin 38 extending out of the package shell 31 and the heat sink 4, and the third pin 38 and the heat sink 4 are isolated by the insulating sheet 6, so that the third pin 38 and the heat sink 4 are mutually insulated. In this way, it is not necessary to increase the thickness of the package shell 31 or increase the distance between the third pin 38 and the heat sink 4 to ensure the insulation distance, and the volume of the power module 3 is reduced.

[0084] In Figure 10 the illustrated embodiment, each power module 3 is arranged in correspondence with one insulating sheet 6. In other embodiments, multiple power modules 3 are arranged, and the multiple power modules 3 are connected with the same insulating sheet 6. For example, Figure 14 another structure of the insulating sheet 6 is illustrated, referring back to Figure 14 , the insulating sheet 6 is fixed to the heat sink 4, and the first metal plates 32 of the multiple power modules 3 are connected with the same insulating sheet 6. In this way, multiple insulating sheets 6 do not need to be separately installed and manufactured, which is beneficial to the production of the power conversion device 20, and the large-area insulating sheet 6 is also beneficial to the separation of the pins (for example, the first pin 34, the second pin 37, or the third pin 38) and the heat sink 4, so that the pins and the heat sink 4 are mutually insulated.

[0085] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which shall be encompassed in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A power conversion device, characterized by, The application relates to a power module, comprising: a device shell; a heat sink, which is at least partially located outside the device shell, or is located inside the device shell; a power module, which is used for converting direct current from a photovoltaic assembly or an energy storage battery into alternating current, and comprises a packaging shell, a first metal plate and a plurality of dies, the packaging shell is used for fixing the first metal plate and accommodating the plurality of dies, a surface on one side of the first metal plate is located inside the packaging shell and is connected with the plurality of dies, and a surface on the other side of the first metal plate is located outside the packaging shell and faces the heat sink; an insulating sheet, which is fixed between the first metal plate and the heat sink.

2. The power conversion device of claim 1, wherein, The power module further comprises a first pin, a part of the first pin is located inside the packaging shell and is fixed to the first metal plate, and the other part of the first pin extends out of the packaging shell.

3. The power conversion device of claim 2, wherein, An edge surface of the first metal plate connects the surfaces on the two sides of the first metal plate, and the first pin is fixed to the edge surface of the first metal plate.

4. A power conversion device according to claim 2 or 3, characterised in that, A part of the insulating sheet is located between the part of the first pin extending out of the packaging shell and the heat sink.

5. The power conversion device according to any one of claims 1 to 4, characterized by, The power module further comprises a second metal plate and a first connecting line; the second metal plate is fixed to the packaging shell, there is a gap between the second metal plate and the first metal plate, a surface on one side of the second metal plate is located inside the packaging shell, and a surface on the other side of the second metal plate is located outside the packaging shell and is connected with the insulating sheet; each of the dies comprises a switch tube, a first pole of the switch tube is connected with the first metal plate, a second pole of the switch tube faces away from the first metal plate, and the first connecting line connects the second metal plate and the second pole of the switch tube.

6. The power conversion device of claim 5, wherein, The power module further comprises a second pin, a part of the second pin is located inside the packaging shell and is fixed to the second metal plate, and the other part of the second pin extends out of the packaging shell.

7. The power conversion device of claim 6, wherein, An edge surface of the second metal plate connects the surfaces on the two sides of the second metal plate, and the second pin is fixed to the edge surface of the second metal plate.

8. A power conversion device according to claim 6 or 7, characterised in that, The surface of the second metal plate located outside the packaging shell is flush with the surface of the first metal plate located outside the packaging shell.

9. A power conversion device according to any one of claims 5-8, characterized in that, The power module further comprises a third pin and a second connecting line; the third pin is fixed to the packaging shell, a part of the third pin is located inside the packaging shell and has a gap with the first metal plate, and the other part of the third pin extends out of the packaging shell; a control pole of the switch tube faces away from the first metal plate, and the second connecting line is located inside the packaging shell and connects the third pin and the control pole of the switch tube.

10. The power conversion device of claim 9, wherein, The third pin is located on the side of the first metal plate facing away from the first pin.

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