Power module, power terminal and power converter

Abstract

The invention provides a power module, a power terminal and a power converter, and the power module comprises a first housing, a substrate, a chip, and a power terminal. The substrate is mounted on a bottom plate of the first shell, the chip is electrically connected with the substrate, and the power terminal is electrically connected with the substrate; the power terminal comprises a second shell, a phase change material and a first cover plate; wherein the second shell comprises a bottom plate and side plates on the periphery, and a first space is defined by the bottom plate and the side plates; the phase change material is arranged in the first space; and the first cover plate covers the second shell and is used for packaging the phase change material in the first space. According to the power module, the power terminal and the power converter provided by the embodiment of the invention, the condition that the temperature of the power terminal is sharply increased can be effectively relieved, and more efficient thermal management is realized, so that the service life of the power module and the like is prolonged, and the maintenance cost and the failure rate are favorably reduced.

Description

Technical Field

[0001] Embodiments of the present application relate to the field of electric power technology, and more specifically, to a power module, a power terminal, and a power converter. Background Art

[0002] With the rapid development of electric vehicles and new energy power generation, the performance of power electronic equipment has received more and more attention. As the core component of the equipment, the performance of the power module directly determines the performance of the entire equipment. At present, research shows that overheating is the core challenge of the reliability of power devices and even power electronic equipment.

[0003] In particular, the development of new energy has dramatically increased the demand for overload operation of power electronic equipment. For example, when electric vehicles climb a slope or accelerate on a flat road, the motor power electronic driver needs to provide greater output power in a short period of time to support vehicle shifting / speeding up / power increase; or when the power system fails and the load fluctuates, the power electronic equipment in the new power system needs to provide additional power to the system to support the dynamic changes of the power grid. The overload power provided above is even 2-3 times or even more than the rated power of the power electronic equipment, which can easily cause the current flowing through the power module and the power terminal to increase sharply in a short period of time.

[0004] As the current through the power terminal increases due to equipment overload, the power module greatly affects the temperature of the power terminal. The temperature control capability of the power terminal directly affects the life of the busbar capacitor directly connected to the power terminal, as well as the life of other components (such as resistors) and equipment connected to the power terminal. Therefore, how to more effectively alleviate the increase in power terminal temperature and achieve more efficient thermal management has become a problem that needs to be solved urgently. Summary of the invention

[0005] The embodiments of the present application provide a power module, a power terminal and a power converter, which can effectively alleviate the situation of a sharp increase in temperature at the power terminal and achieve more efficient thermal management, thereby increasing the life of the power module, the bus capacitor connected to the power terminal, and other components (such as resistors) and equipment connected to the power terminal, helping to reduce maintenance costs and failure rates.

[0006] In a first aspect, a power module is provided, comprising: a first shell, a substrate, a chip and a power terminal; the substrate is mounted on the inner bottom wall of the first shell, the chip is placed on the surface of the substrate and is electrically connected to the substrate, the power terminal is placed outside the first shell, and one end of the power terminal extends into the first shell and is electrically connected to the substrate; the power terminal comprises a second shell, a phase change material and a first cover plate; wherein the second shell comprises a bottom plate and surrounding side plates, the bottom plate and the side plates enclose a first space, and the second shell has conductivity; the phase change material is arranged in the first space; the first cover plate is covered on the second shell, and is used to encapsulate the phase change material in the first space.

[0007] The power terminal provided in the embodiment of the present application can effectively alleviate the situation of rapid temperature increase and achieve more efficient thermal management, thereby increasing the service life and stability of the power module and the components or equipment connected to the power terminal, and helping to reduce maintenance costs and failure rates.

[0008] In combination with the first aspect, in an implementation of the first aspect, the second shell also includes a partition structure, which is used to divide the first space into multiple cavities, and the phase change material includes multiple phase change material units, and the multiple phase change material units are correspondingly arranged in the multiple cavities.

[0009] In combination with the first aspect, in an implementation manner of the first aspect, the first space is in a multi-groove shape or a honeycomb shape.

[0010] The embodiment of the present application arranges multiple phase change materials in multiple grooves inside the second shell, which is conducive to increasing the contact area between the phase change material and the second shell, and the distance from the inside to the outside of the phase change material is shortened, thereby shortening the time required for complete melting, making the phase change material more complete when the phase change occurs, absorbing more latent heat, so that the temperature control of the power terminal can be achieved for a longer time. On the other hand, after the phase change material melts into the liquid phase after the phase change occurs, the thermal conductivity will further decrease. The separation structure can also help the phase change material to conduct heat, effectively improving its thermal conductivity, so that the phase change occurs more completely.

[0011] In combination with the first aspect, in an implementation manner of the first aspect, the partition structure is connected to the bottom plate or the side plate.

[0012] Optionally, the partition structure and the bottom plate or the side plate may be welded or integrally formed.

[0013] When the partition structure of the embodiment of the present application is connected to the bottom plate or the side plate of the second shell, heat can be effectively transferred through the contact between the phase change material, the partition structure and the second shell, thereby improving the temperature control effect of the power terminal.

[0014] In combination with the first aspect, in an implementation manner of the first aspect, the first connection portion includes a plurality of contacts, and the plurality of contacts are fixedly connected inside the power module.

[0015] Optionally, the first connection portion may not include a plurality of contacts, that is, the first connection portion may be fixedly connected inside the power module in an integral manner.

[0016] In combination with the first aspect, in an implementation manner of the first aspect, the second connection portion includes a circular hole structure, and the circular hole structure is electrically connected to an external circuit.

[0017] In the embodiment of the present application, the first connection part and the second connection part form a tight connection with the inside and the outside respectively, thereby improving the reliability of the power terminal in the device.

[0018] In combination with the first aspect, in an implementation of the first aspect, the first cover plate includes a first mounting hole, the second shell further includes a second mounting hole, and the first mounting hole and the second mounting hole are arranged correspondingly; the power terminal also includes a first fixing member, which is arranged between the first mounting hole and the second mounting hole, and is used to tightly connect the first cover plate and the second shell.

[0019] The embodiment of the present application can encapsulate the phase change material inside the second shell through the mounting hole and the first fixing member to prevent the phase change material from turning into liquid and flowing freely after the phase change occurs, or the liquid phase change material from flowing out, resulting in failure of the phase change temperature control.

[0020] In combination with the first aspect, in an implementation manner of the first aspect, the phase change material is a low temperature metal phase change material.

[0021] When the phase change material of the embodiment of the present application is a low-temperature metal phase change material, it can have better heat transfer and electrical conductivity properties compared to traditional phase change materials, which helps to improve heat transfer efficiency and reduce the on-resistance of the power terminal.

[0022] In combination with the first aspect, in an implementation of the first aspect, the substrate includes a first layer board, an intermediate layer and a second layer board, and the first layer board, the intermediate layer and the second layer board are stacked and connected in sequence; wherein the first layer board is used to electrically connect with the chip and the first connecting part, the intermediate layer is used for insulation and support, and the second layer board is connected to the first shell.

[0023] The substrate provided in the embodiment of the present application is used to establish a smooth thermal channel at the bottom of the chip, eliminate the heat junctions generated during the operation of the power module, play a role in electrical insulation and heat conduction, and can also transmit current.

[0024] In combination with the first aspect, in an implementation manner of the first aspect, the first connection portion includes a plurality of contacts, and the plurality of contacts are welded to the first layer board.

[0025] In combination with the first aspect, in an implementation manner of the first aspect, the power module further includes a bonding wire, the chip is welded to the first layer board, and the chip is electrically connected to the first layer board through the bonding wire.

[0026] Optionally, the power module includes a plurality of chips arranged in rows on a surface of a substrate.

[0027] In combination with the first aspect, in an implementation manner of the first aspect, the power module further includes a second cover plate, and the second cover plate is covered on the first shell.

[0028] In combination with the first aspect, in an implementation manner of the first aspect, the power module includes a plurality of the power terminals, and the plurality of the power terminals are respectively used as an input end and an output end of the power module.

[0029] Exemplarily, the power module includes three power terminals, which respectively serve as the positive and negative input terminals and output terminals of the power module. The first power terminal and the second power terminal are used for DC input, and the third power terminal is used for AC output.

[0030] In a second aspect, a power terminal is provided, comprising: a second shell, the second shell comprising a bottom plate and surrounding side plates, the bottom plate and the side plates enclosing a first space, the second shell having conductive capability; a phase change material disposed in the first space; and a first cover plate, disposed on the second shell, for encapsulating the phase change material in the first space.

[0031] The power terminal provided in the embodiment of the present application can effectively alleviate the situation of rapid temperature increase and achieve more efficient thermal management, thereby increasing the service life and stability of the power module and bus capacitor, and helping to reduce maintenance costs and failure rates.

[0032] In combination with the second aspect, in an implementation of the second aspect, the second shell also includes a partition structure, which is used to divide the first space into multiple cavities, and the phase change material includes multiple phase change material units, and the multiple phase change material units are correspondingly arranged in the multiple cavities.

[0033] In combination with the second aspect, in an implementation manner of the second aspect, the first space is in a multi-groove shape or a honeycomb shape.

[0034] The embodiment of the present application arranges multiple phase change materials in multiple grooves inside the second shell, which is conducive to increasing the contact area between the phase change material and the second shell, and the distance from the inside to the outside of the phase change material is shortened, thereby shortening the time required for complete melting, making the phase change material more complete when the phase change occurs, absorbing more latent heat, so that the temperature control of the power terminal can be achieved for a longer time. On the other hand, after the phase change material melts into the liquid phase after the phase change occurs, the thermal conductivity will further decrease. The separation structure can also help the phase change material to conduct heat, effectively improving its thermal conductivity, so that the phase change occurs more completely.

[0035] In combination with the second aspect, in an implementation manner of the second aspect, the partition structure is connected to the bottom plate or the side plate.

[0036] Optionally, the partition structure and the bottom plate or the side plate may be welded or integrally formed.

[0037] When the partition structure of the embodiment of the present application is connected to the bottom plate or the side plate of the second shell, heat can be effectively transferred through the mutual contact between the phase change material, the partition structure and the second shell, thereby improving the temperature control effect of the power terminal.

[0038] In combination with the second aspect, in an implementation manner of the second aspect, the first connection portion includes a plurality of contacts, and the plurality of contacts are fixedly connected inside the power module.

[0039] Optionally, the first connection portion may not include a plurality of contacts, that is, the first connection portion may be fixedly connected inside the power module in an integral manner.

[0040] In combination with the second aspect, in an implementation manner of the second aspect, the second connection portion includes a circular hole structure, and the circular hole structure is electrically connected to an external circuit.

[0041] In the embodiment of the present application, the first connection part and the second connection part form a tight connection with the inside and the outside respectively, thereby improving the reliability of the power terminal in the device.

[0042] In combination with the second aspect, in an implementation of the second aspect, the first cover plate includes a first mounting hole, the second shell further includes a second mounting hole, and the first mounting hole and the second mounting hole are arranged correspondingly; the power terminal also includes a first fixing member, which is arranged between the first mounting hole and the second mounting hole, and is used to tightly connect the first cover plate and the second shell.

[0043] The embodiment of the present application can encapsulate the phase change material inside the second shell through the mounting hole and the first fixing member to prevent the phase change material from turning into liquid and flowing freely after the phase change occurs, or the liquid phase change material from flowing out, resulting in failure of the phase change temperature control.

[0044] In combination with the second aspect, in an implementation manner of the second aspect, the phase change material is a low temperature metal phase change material.

[0045] When the phase change material of the embodiment of the present application is a low-temperature metal phase change material, it can have better heat transfer and electrical conductivity properties compared to traditional phase change materials, which helps to improve heat transfer efficiency and reduce the on-resistance of the power terminal.

[0046] In a third aspect, a power converter is provided, comprising a filter and the power module described in the first aspect and any one of the implementations of the first aspect, wherein the input end of the filter is connected to the output end of the power module, and the output end of the filter outputs electrical energy to a load.

[0047] In a fourth aspect, a photovoltaic inverter is provided, comprising an MPPT circuit, a filter, a bus capacitor and a power module as described in the first aspect and any one of the implementations of the first aspect, wherein the filter is connected to the power module to form an inverter circuit, the output end of the MPPT circuit is connected to the input end of the bus capacitor, and the output end of the bus capacitor is connected to the input end of the inverter circuit.

[0048] In a fifth aspect, a method for manufacturing a power terminal is provided, comprising: obtaining a processed and formed second shell, placing a phase change material in the second shell under a vacuum or inert gas environment; continuing to place the phase change material in a vacuum or inert gas environment to cool and form; fixing a first cover plate on the second shell so that the phase change material is encapsulated in the second shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 It is a schematic diagram of a power module provided in an embodiment of the present application.

[0050] Figure 2 It is a schematic diagram of a power module provided in an embodiment of the present application.

[0051] Figure 3 It is a schematic diagram of a power terminal provided in an embodiment of the present application.

[0052] Figure 4 It is a schematic diagram of a power terminal provided in an embodiment of the present application.

[0053] Figure 5 It is a schematic diagram of a power terminal provided in an embodiment of the present application.

[0054] Figure 6 It is a schematic diagram of a power terminal provided in an embodiment of the present application.

[0055] Figure 7It is a schematic diagram of the electrical connection of a power module provided in an embodiment of the present application.

[0056] Figure 8 It is a schematic diagram of a method for manufacturing a power terminal provided in an embodiment of the present application.

[0057] Reference numerals:

[0058] 100 - power terminal; 101 - second shell; 102 - phase change material; 103 - first cover plate; 1011 - first connection part; 1012 - second connection part; 1013 - contact point; 1031 - first mounting hole; 1014 - second mounting hole; 200 - power module; 201 - first shell; 202 - substrate; 203 - chip. DETAILED DESCRIPTION

[0059] The following explains the terms that may appear in the embodiments of the present application.

[0060] Phase change material: A material that changes state and provides latent heat without changing temperature. The process of changing physical properties is called phase change, and the phase change material will absorb or release a large amount of latent heat. In particular, latent heat refers to the specific energy that a substance absorbs or releases during a phase change without changing temperature. Phase change materials (PCMs) usually have high density, low vapor pressure and good thermal conductivity, which can absorb a large amount of heat during the phase change process, thereby achieving the effect of endothermic regulation. For example, when the temperature of a waxy substance exceeds its melting point, it will change from solid to liquid, absorbing heat from the surrounding environment and forming latent heat until it is completely melted. Similarly, when the temperature decreases, the phase change material will change from liquid to solid, releasing latent heat to increase the temperature of the surrounding environment, achieving the effect of cooling regulation. Phase change materials are widely used in energy-saving thermal management and temperature stabilization in the fields of construction, electronics, chemicals, energy, etc. due to their high density, long-lasting and stable energy storage characteristics and low space requirements.

[0061] Maximum effective current value or current carrying capacity of the power module terminal: the maximum current carrying capacity of the power module under steady-state conditions under certain heat dissipation boundary conditions.

[0062] Thermal damage to power devices: Power devices working in an environment with large temperature changes are prone to thermal expansion and contraction, leading to changes in the structure and performance of power devices, thereby causing thermal damage.

[0063] Capacitor thermal damage: High temperature can cause the dielectric layer inside the capacitor to shift and decompose, the electrodes and leads to looseness, and increase the number of potential spots inside the capacitor, which can change the capacitance value and leakage current of the capacitor, and even cause the capacitor to short-circuit or spark. At the same time, thermal damage can also cause abnormal conditions such as overvoltage and overcurrent inside the capacitor, which accelerates the occurrence of thermal damage.

[0064] Equipment overload will cause the current through the power terminal to increase, greatly affecting the temperature of the power terminal. The specific mechanism is as follows: When the power module is working, the current passes through the power module terminal, and the circuit impedance inside the power terminal will generate a large amount of Joule heat. In addition to the parameters of the power terminal itself, this phenomenon is also related to the contact resistance between the power terminal and the external circuit. The heat generated on the power terminal when the power module is working will cause the power terminal to heat up; in particular, under normal circumstances, the power module terminal will not be equipped with corresponding heat dissipation equipment, and then the heat of the power terminal is directly transferred to the bus capacitor directly connected to the power terminal, as well as other components (such as resistors) and equipment connected to the power terminal.

[0065] Therefore, the temperature control capability of the power terminal will directly affect the life of the busbar capacitor core directly connected to the power terminal and the life of other components (such as resistors) and equipment connected to the power terminal. In particular, if the capacitor connected to the power terminal works at a temperature exceeding the rated temperature, it will cause the following effects:

[0066] (1) The capacitance of the capacitor will decrease. The capacitance of the capacitor is one of the most important electrical parameters of the capacitor. When the capacitor works in a high temperature environment, the high temperature will accelerate the polarization chemical reaction in the dielectric material, and the molecules of the internal dielectric will undergo mechanical swings, increasing the loss of the dielectric material and causing the capacitance to decrease.

[0067] (2) The life of the capacitor will be shortened. The long-term operation of the capacitor in a high temperature environment will accelerate the aging and loss of the internal components, thus shortening the life of the capacitor. In addition, high temperature will accelerate the air oxidation rate of the material, causing the metal materials such as the inter-electrode and plate inside the capacitor to deteriorate, further causing the capacitor to fail faster.

[0068] (3) Capacitors can leak electricity. Under high temperature conditions, the internal components of capacitors deteriorate and the catalyst layer on the surface of the capacitors decomposes, which easily forms conductive particles, so internal leakage is inevitable. In addition, when the inter-electrode dielectric breaks or degrades, a conductive DC arc will appear, forming a circuit between the plates, causing leakage. In high-power applications, leakage problems will be a serious safety hazard.

[0069] Therefore, the embodiments of the present application provide a power module, a power terminal and a power converter, which can more effectively alleviate the temperature rise of the power terminal, achieve more efficient thermal management of the power module, and extend the life of the power module, the bus capacitor connected to the power terminal, and other components (such as resistors) and equipment.

[0070] The following uses a common photovoltaic inverter as an application scenario. Figure 3 and Figure 4 The technical solution in this application is described.

[0071] Photovoltaic inverters include maximum power point tracking (MPPT) circuits, filters, bus capacitors, and power modules. The MPPT circuit is used to fully utilize solar cells and make them operate at the maximum power point; the power module and the filter constitute an inverter circuit, which is used to convert DC power into AC power and control the output voltage and frequency; the bus capacitor is used to improve the stability and purity of the voltage. Among them, the output end of the MPPT circuit is connected to the input end of the bus capacitor, and the output end of the bus capacitor is connected to the input end of the inverter circuit; the power terminal in the power module is directly connected to the bus capacitor as the output end or input end.

[0072] The embodiment of the present application provides a power terminal 100, including: a second shell 101, a first cover plate 103 and a phase change material 102; the second shell 101 is a semi-enclosed structure with an open top, including a bottom plate and surrounding side plates, and the bottom plate and the surrounding side plates enclose a first space; the phase change material 102 is arranged inside the cavity of the second shell 101, and the first cover plate 103 is covered on the second shell 101, so that the phase change material 102 can be encapsulated in the second shell 101; wherein the second shell 101 also includes a first connecting portion 1011 and a second connecting portion 1012, the first connecting portion 1011 is used for electrical connection inside the power module 200, and the second connecting portion 1012 is used for electrical connection of an external circuit.

[0073] Specifically, when the entire power module is close to full load or overload operation, the current will generate a large amount of heat at the power terminal of the power module. This heat will cause the power terminal to heat up to 100°C or other temperatures in a short time; when the phase change material inside the power terminal reaches the phase change temperature point, the phase change material undergoes enthalpy change. At this time, the phase change material absorbs heat without changing the temperature, and the heat generated by the power terminal is absorbed, thereby more effectively controlling the temperature of the power terminal and achieving thermal management of the power module terminal, thereby protecting the bus capacitor and other components (such as resistors) and equipment connected to the power terminal.

[0074] The power terminal provided in the embodiment of the present application can effectively alleviate the situation of rapid temperature increase and achieve more efficient thermal management, thereby increasing the service life and stability of the power module and bus capacitor, and helping to reduce maintenance costs and failure rates.

[0075] Optionally, the first connection portion 1011 includes a plurality of contacts 1013, and the electrical connection between the first connection portion 1011 and the inside of the power module 200 can be achieved by welding the plurality of contacts 1013 to be fixed inside the power module 200, so that a reliable electrical connection is formed inside the power module 200. Optionally, the first connection portion 1101 can also be fixedly connected inside the power module in an integral manner, but the structure and connection method of the first connection portion 1011 are not limited thereto in the embodiments of the present application.

[0076] Optionally, the second connection portion 1012 includes a circular hole structure, and the circular hole structure of the second connection portion 1012 can be connected to the external circuit by means of screws, busbars or high current wires to form a reliable and tight mechanical connection. The tightness of the mechanical connection will affect the size of the contact resistance, thereby affecting the heating characteristics of the power terminal 100. Therefore, a fine processing method can be used for the second connection portion 1012 to make the surface of the power terminal 100 smoother and the size of the circular hole structure more accurate. The structure and connection method of the second connection portion 1012 are not limited to this.

[0077] Optionally, the second housing 101 may further include a partition structure, which forms a plurality of grooves in the first space, such as Figure 5 (a) and Figure 5 As shown in (b) in FIG. 1 , the partition structure may be in the form of a long sheet, and a plurality of rib grooves may be provided inside the corresponding second housing 101; Figure 4 , Figure 6 (a) and Figure 6 As shown in (b), the partition structure may be in a grid shape, corresponding to a plurality of rectangular grooves or circular grooves inside the second shell 101. The plurality of phase change materials 102 are arranged in the plurality of grooves inside the second shell 101, which is conducive to increasing the contact area between the phase change material 102 and the second shell 101, and the distance from the inside to the outside of the phase change material 102 is shortened, thereby shortening the time required for complete melting, so that the phase change material 102 is more complete when the phase change occurs, and absorbs more latent heat, so that the temperature control of the power terminal 100 can be achieved for a longer time. It should be noted that the plurality of phase change materials 102 arranged in the plurality of grooves may be the same type of phase change material or different types of phase change materials, which is not specifically limited in the embodiment of the present application.

[0078] Optionally, the first space of the second shell 101 may also be honeycomb or hollow, which is not specifically limited in the embodiment of the present application. It should be noted that after the phase change material 102 undergoes phase change and melts into a liquid phase, the thermal conductivity will further decrease. The separation structure can also help the phase change material 102 to conduct heat, effectively improve its thermal conductivity, make the phase change occur more completely, absorb more potential, and thus achieve longer temperature control of the power terminal 100.

[0079] Optionally, an L-shaped groove can be opened on the top of the side panel of the second shell 101 from the inside to the outside, so that when the first cover plate 103 is installed on the second shell 101, the edge of the first cover plate 103 overlaps with the L-shaped groove, that is, the side panel and part of the bottom plate of the first cover plate 103 overlap with the side panel of the second shell 101, and the upper surface of the first cover plate 103 and the upper surface of the side panel of the second shell 101 are located on the same horizontal plane. This design can optimize the appearance of the power terminal 100 and can also facilitate the subsequent installation of the power terminal 100 into the equipment for use, but the embodiments of the present application are not limited to this.

[0080] Optionally, the first cover plate 103 includes one or more first mounting holes 1031, and the second shell 101 also includes one or more second mounting holes 1014. The first mounting holes 1031 and the second mounting holes 1014 are arranged one by one, and a first fixing piece is arranged between the first mounting hole 1031 and the second mounting hole 1014 to tightly connect and fix the first cover plate 103 and the second shell 101; illustratively, the first mounting hole 1031 and the second mounting hole 1014 can be round holes, and the first fixing piece can be a bolt, nut or screw, which is not specifically limited in the embodiment of the present application. Through the mounting holes and the first fixing piece, the phase change material 102 can be encapsulated inside the second shell 101 to prevent the phase change material 102 from becoming a liquid and flowing freely after the phase change occurs, or the liquid phase change material 102 flows out, resulting in failure of the phase change temperature control.

[0081] Optionally, the phase change material 102 may be a solid-liquid phase change material 102 or a solid-gas phase change material 102. It should be noted that the phase change material 102 reaching the phase change temperature point and undergoing enthalpy change is related to the selected phase change material 102. Compared with the traditional phase change material 102, the low temperature metal phase change material has better heat transfer and electrical conductivity, improves the heat transfer efficiency and reduces the on-resistance of the power terminal 100. The traditional phase change material 102, such as paraffin and erythritol, has poor thermal conductivity and is not suitable for the sudden increase of heat flux in the power electronic power module 200. The electrical conductivity is extremely weak, but those skilled in the art can select the phase change material 102 according to actual needs, and the embodiment of the present application does not specifically limit this.

[0082] Exemplarily, the phase change material 102 may be a low temperature metal phase change material such as a bismuth alloy or other alloy metals. The low temperature metal phase change material may be a liquid metal, and its physical properties are shown in Table 1. The low temperature metal phase change material has better thermal conductivity and lower electrical impedance among phase change materials, and can effectively promote heat transfer and reduce the overall resistance of the terminal, but the embodiments of the present application are not limited thereto.

[0083] Table 1

[0084] name Latent heat (J / g) Heat capacity (J / (g·K)) Phase transition point(℃) Liquid Metal 100 21.783 0.280(80℃) / 0.200(125℃) 97(94-100)

[0085] Optionally, the second shell 101 may be made of brass or other metal materials, but the embodiment of the present application is not limited thereto.

[0086] The power terminal 100 provided in the embodiment of the present application can be widely used in (but not limited to) many power electronic devices (including direct current-to-direct current (DC-DC), direct current-to-alternating current (DC-AC), and alternating current-to-alternating current (AC-AC) converters) of new power systems. With the development of new energy sources, more and more power electronic devices are connected to the power grid, and these power electronic devices have very high requirements for transient performance and temperature management. The power terminal of the present application can effectively reduce temperature fluctuations, improve transient performance, and reduce large temperature rises in a short period of time to protect capacitors. Furthermore, new energy grid-connected power electronic converters can work more reliably and efficiently, improve the safety and reliability of the power grid, and promote the development of sustainable energy.

[0087] In addition, the power terminal provided in the embodiment of the present application can also be used in automotive-grade power modules, including electric vehicles, hybrid vehicles, etc. In order to solve the problem of temperature fluctuation of power terminals caused by large fluctuations in vehicle power, the phase change material of the power terminal can achieve peak shaving and valley filling of heat, avoiding the extremely high short-term temperature rise of the power terminal to damage the capacitor. Through the power terminal provided in the embodiment of the present application, the vehicle power module can work more stably and reliably, improve the performance and life of the entire vehicle, and reduce maintenance costs and failure rates.

[0088] The present application also provides a power module 200, such as Figure 1 and Figure 2 As shown, it includes a first shell 201, a substrate 202, a chip 203 and one or more of the aforementioned power terminals 100, wherein the first shell 201 is a semi-enclosed structure with an open top, the substrate 202 is installed on the bottom inner wall of the first shell 201, the chip 203 is connected to the surface of the substrate 202, and the first connecting part 1011 of the power terminal 100 is connected to the surface of the substrate 202.

[0089] Optionally, the substrate 202 is used to establish a smooth thermal channel at the bottom of the chip 203, eliminate the hot junction generated during the operation of the power module 200, play an electrical insulation and heat conduction role, and can also transmit current. The substrate 202 may include a first layer, a second layer, and an intermediate layer. The first layer is used for electrical connection, the second layer is connected to the first shell 201, and the intermediate layer is used to provide insulation effect and structural support; the first layer and the second layer can be made of copper, and the intermediate layer can be made of ceramic insulating material, such as aluminum oxide or aluminum nitride. It should be noted that copper has good thermal conductivity, but the thermal expansion coefficient of copper is close to three times that of the chip 203. Therefore, a ceramic copper clad plate or a multi-layer ceramic copper clad plate can be used to transitionally solve the three-fold difference, but the embodiments of the present application are not limited to this.

[0090] Optionally, the number of chips 203 of the power module 200 can be one or more, and can be arranged in rows on the surface of the substrate 202; the connection between the chip 203 and the substrate 202 can be that the chip 203 is welded on the surface of the first layer board of the substrate 202, and its electrical connection can be achieved by connecting the chip 203 to the first layer board through bonding wires, which is not specifically limited in the embodiments of the present application.

[0091] Exemplarily, the first shell 201 may include a bottom plate and surrounding side plates. The bottom plate of the first shell 201 may use aluminum or aluminum silicon carbide as a substrate, and the side plates of the first shell 201 may use plastic or aluminum, etc. The embodiment of the present application does not specifically limit this.

[0092] Optionally, the power module 200 further includes a second cover plate, which is disposed on the first housing 201. The second cover plate may be made of plastic or metal, which is not specifically limited in the embodiment of the present application.

[0093] The power module may include a plurality of power terminals. For example, Figure 7 This is the electrical connection diagram of the power module. The power module includes three power terminals, which are respectively used as the positive and negative input terminals and output terminals of the power module. For example, the first power terminal and the second power terminal are used for DC input, the first power terminal is used for DC positive (DC+) input, the second power terminal is used for DC negative (DC-) input, and the third power terminal is used for AC output. By controlling the temperature of the power terminals at the input and output ends, it is possible to effectively alleviate the situation of a sharp increase in temperature caused by a large current passing through in a short time, thereby improving the stability of the entire power module and extending its service life.

[0094] An embodiment of the present application also provides a photovoltaic inverter, including an MPPT circuit, a filter, a bus capacitor and the aforementioned power module, the filter is connected to the power module to form an inverter circuit, the output end of the MPPT circuit is connected to the input end of the bus capacitor, and the output end of the bus capacitor is connected to the input end of the inverter circuit.

[0095] An embodiment of the present application also provides a power converter, including a filter and the aforementioned power module, wherein the filter is connected to the output end of the power module, the converted electric energy output by the power module is transmitted to the filter for smoothing, and the output end of the filter outputs the electric energy to the load.

[0096] The present application also provides a method for manufacturing a power terminal 100, taking a liquid phase change material as an example. Figure 8 As shown, the specific steps are as follows:

[0097] S101 , obtaining a processed second shell 101 , and injecting a phase change material 102 into the second shell 101 under a vacuum or inert gas environment.

[0098] Specifically, the power terminal 100 can be machined by a subtractive processing method, a rectangular aluminum alloy block of suitable size is machined, and the interior of the cavity of the second housing 101 is machined into the following shape: Figures 3 to 6 In a vacuum or inert gas environment, the phase change material 102 is melted by heat and injected into the second housing 101. It should be noted that if the phase change material 102 is exposed to air, it will be oxidized, affecting its thermal conductivity and latent heat.

[0099] S102 , cooling and molding the phase change material 102 in the second housing 101 .

[0100] Specifically, the cooling and forming of the phase change material 102 is still carried out in a vacuum or inert gas environment. The phase change material 102 is melted and injected into the second shell 101, and then cooled and formed, which helps the phase change material 102 to fully contact the inner wall of the second shell 101, thereby reducing the contact thermal resistance and improving the heat conduction efficiency. It should be noted that the cooling and forming of the phase change material 102 can be natural cooling, or the vacuum tank where the second shell 101 is placed in a natural temperature water bath for cooling, which is not specifically limited in the embodiments of the present application.

[0101] S103 , fixing and connecting the first cover plate 103 to the second shell 101 .

[0102] Specifically, mounting holes can be set on the first cover plate 103 and the second shell 101. By setting a first fixing member on the mounting hole, the first cover plate 103 and the second shell 101 are tightly connected to prevent the phase change material 102 from turning into liquid and flowing freely after the phase change occurs, or even the liquid phase change material 102 flows out, causing the phase change temperature control to fail.

[0103] The method for manufacturing the power terminal provided in the embodiment of the present application can encapsulate the phase change material in the power terminal, and achieve better temperature control of the power terminal through the phase change effect of the phase change material, which helps to improve the operating stability of the entire power module and thereby extend the life of the bus capacitor.

[0104] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0105] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0106] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0107] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. Specifically, the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0108] The term "plurality" used in the present application refers to two or more (including two).

[0109] In the embodiments of the present application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. Among them, A and B can be singular or plural. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, ab, ac, bc, or abc, where a, b, c can be single or multiple.

[0110] It should be noted that in the embodiments of the present application, the terms "upper", "lower", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0111] The limitations such as symmetry (e.g., axisymmetry, or center symmetry, etc.) and sameness (e.g., same length, same width, etc.) mentioned in the embodiments of the present application are all for the current technological level, rather than being absolutely strict definitions in a mathematical sense. There may be a deviation of a predetermined threshold or a predetermined angle between the two.

[0112] Specifically, in various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0113] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A power module, characterized in that: include: A first housing, a substrate, a chip and a power terminal; The substrate is mounted on the inner bottom wall of the first housing, the chip is placed on the surface of the substrate and is electrically connected to the substrate, the power terminal is placed outside the first housing, and one end of the power terminal extends into the first housing and is electrically connected to the substrate; The power terminal includes a second housing, a phase change material and a first cover plate; Among them, the second shell includes a bottom plate and surrounding side plates, the bottom plate and the side plates enclose a first space, and the second shell has conductive ability; the phase change material is arranged in the first space; the first cover plate is covered on the second shell, and is used to encapsulate the phase change material in the first space.

2. The power module according to claim 1, characterized in that: The second shell further includes a partition structure, and the partition structure is used to divide the first space into a plurality of cavities. The phase change material includes a plurality of phase change material units, and the plurality of phase change material units are correspondingly arranged in the plurality of cavities.

3. The power module according to claim 2, characterized in that: The first space is in a multi-groove shape or a honeycomb shape.

4. The power module according to claim 2, characterized in that: The partition structure is connected to the bottom plate or the side plate.

5. The power module according to claim 1, characterized in that: The second shell further includes a first connection portion and a second connection portion, wherein the first connection portion and the second connection portion are arranged outside the first space, the first connection portion is used for electrically connecting to the substrate, and the second connection portion is used for electrically connecting to an external circuit.

6. The power module according to claim 5, characterized in that: The first connection portion includes a plurality of contacts.

7. The power module according to any one of claims 1 to 6, characterized in that: The first cover plate includes a first mounting hole, the second housing further includes a second mounting hole, and the first mounting hole and the second mounting hole are arranged correspondingly; The power terminal further includes a first fixing member, which is disposed between the first mounting hole and the second mounting hole and is used to tightly connect the first cover plate and the second housing.

8. The power module according to any one of claims 1 to 6, characterized in that: The phase change material is a low temperature metal phase change material.

9. The power module according to any one of claims 1 to 6, characterized in that: The substrate comprises a first layer, an intermediate layer and a second layer, wherein the first layer, the intermediate layer and the second layer are sequentially stacked and connected; The first layer board is used for electrical connection with the chip and the power terminal, the middle layer is used for insulation and support, and the second layer board is connected with the inner bottom wall of the first shell.

10. The power module according to claim 9, characterized in that: The power module further includes bonding wires, and the chip is electrically connected to the first layer board via the bonding wires.

11. The power module according to claim 9, characterized in that: The power module further includes a second cover plate, and the second cover plate is covered on the first shell.

12. The power module according to claim 1, characterized in that: The power module includes at least three power terminals, which are respectively used for the positive input terminal, the negative input terminal and the output terminal of the power module.

13. A power terminal, characterized in that: include: A second shell, the second shell comprising a bottom plate and surrounding side plates, the bottom plate and the side plates enclose a first space, and the second shell has a conductive capability; A phase change material is disposed in the first space; The first cover plate is disposed on the second shell and is used to encapsulate the phase change material in the first space.

14. The power terminal according to claim 13, characterized in that: The second shell further includes a partition structure, and the partition structure is used to divide the first space into a plurality of cavities. The phase change material includes a plurality of phase change material units, and the plurality of phase change material units are correspondingly arranged in the plurality of cavities.

15. A power converter, characterized in that: The invention comprises a filter and a power module as claimed in any one of claims 1 to 12, wherein the input end of the filter is connected to the output end of the power module, and the output end of the filter outputs electric energy to a load.

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