Diode and photovoltaic module

Abstract

The invention relates to a diode and a photovoltaic module. The diode comprises a second substrate layer, an anode layer, a first substrate layer and a cathode layer which are arranged in sequence, a buffer layer attached to the first substrate layer is arranged in the cathode layer; the buffer layer comprises a plurality of buffer areas; the material in each buffer region is the same as the material in the anode layer, and the doping concentration of each buffer region is smaller than the doping concentration of the anode layer and larger than the doping concentration of the substrate layer; channels with preset patterns are formed in the second substrate layer in a central symmetry or axial symmetry mode, and a channel for liquid media to circulate is formed when the second substrate layer is attached to the cathode layer. According to the embodiment, the liquid medium can take away heat generated by the diode in the flowing process, the temperature in the diode can be reduced, and reliable work of the diode is guaranteed.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic devices, and in particular to a diode and a photovoltaic module. Background Art

[0002] When the reverse voltage of the PN junction in the diode increases, the electric field in the space charge region increases. The energy obtained by the electrons and holes in the space charge region increases under the action of the electric field. The electrons and holes moving in the crystal will constantly collide with the crystal atoms. When the energy of the electrons and holes is large enough, the electrons in the covalent bonds can be excited to form free electron-hole pairs through such collisions. This phenomenon is called collision ionization. The newly generated electrons and holes, like the original electrons and holes, also move in the opposite direction under the action of the electric field, regain energy, and can generate electron-hole pairs through collisions. This is the multiplication effect of carriers. When the reverse voltage increases to a certain value, the multiplication of carriers is like an avalanche on a steep snowy slope. The number of carriers increases much faster, causing the reverse current to increase sharply, so the PN junction undergoes avalanche breakdown.

[0003] However, as the voltage requirements of the diode become higher and higher (such as above 2000V), the diode will experience secondary avalanche. That is, the electric field near the NN+ junction becomes stronger due to the avalanche electrons, causing the diode to experience secondary avalanche near the NN+ junction. At this time, a large current passes through the diode instantly and generates a large amount of heat energy. The large amount of heat energy cannot be dissipated in a short time and will burn out the diode. Summary of the invention

[0004] The present disclosure provides a diode and a photovoltaic module to solve the deficiencies of the related art.

[0005] According to a first aspect of an embodiment of the present disclosure, a diode is provided, comprising an anode layer, a first substrate layer, a cathode layer, and a second substrate layer arranged in sequence; a buffer layer bonded to the first substrate layer is arranged in the cathode layer; the buffer layer comprises a plurality of buffer regions; the material in each buffer region is the same as the material in the anode layer, and the doping concentration of each buffer region is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; a channel with a preset pattern that is symmetrical about the center or axis is formed on the second substrate layer, and a channel for the flow of a liquid medium is formed when the second substrate layer is bonded to the cathode layer.

[0006] Optionally, the channel of the preset pattern includes a central portion, an edge portion and a connecting portion; the central portion and the connecting portion are arranged using vias; the connecting portion is arranged using a blind hole for connecting the central portion and the connecting portion, so that the liquid medium in the central portion flows to the edge portion, or the liquid medium in the edge portion flows to the central portion.

[0007] Optionally, a valve is provided in the central portion and / or the edge portion, and the valve is used to control the flow direction of the liquid medium; the valve is used to open when the flow direction of the liquid medium is the same as a preset direction and close when the flow direction of the liquid medium is opposite to the preset direction.

[0008] Optionally, the diode also includes an arc-shaped groove, which is arranged at the edge of the PN junction formed by the anode layer and the first substrate layer; and a protruding structure is formed at the PN junction formed by the cathode layer of the diode and the first substrate layer; the diode also includes a thermal conductive adhesive layer, which is arranged on one side of the protruding structure to conduct heat at the protruding structure.

[0009] Optionally, the thermal conductive adhesive layer extends to one side of the second substrate layer.

[0010] Optionally, the thickness of the plurality of buffer regions increases sequentially from the inside to the outside, and / or the area of ​​the plurality of buffer regions increases sequentially from the inside to the outside.

[0011] Optionally, the doping concentration of each buffer region among the multiple buffer regions is the same, or the doping concentration of the multiple buffer regions increases sequentially from the inside to the outside.

[0012] Optionally, the areas of the multiple buffer regions increase sequentially from the inside to the outside.

[0013] Optionally, the doping concentration of each buffer region among the multiple buffer regions is the same, or the doping concentration of the multiple buffer regions increases sequentially from the inside to the outside.

[0014] According to a second aspect of the embodiments of the present disclosure, there is provided a photovoltaic module, comprising a diode as described in any one of the first aspects.

[0015] Optionally, a heat dissipation device is further included; the heat dissipation device is provided with an insertion port; the channel of the preset pattern includes a central portion and an edge portion, and the pins of the central portion and the edge portion are inserted into the insertion port to allow the liquid medium in the heat dissipation device and the liquid medium in the groove of the preset image to circulate.

[0016] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0017] The diode provided by the embodiment of the present disclosure may include an anode layer, a first substrate layer, a cathode layer, and a second substrate layer arranged in sequence; a buffer layer bonded to the first substrate layer is arranged in the cathode layer; the buffer layer includes a plurality of buffer regions; the material in each buffer region is the same as the material in the anode layer, and the doping concentration of each buffer region is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; a channel with a preset pattern of central symmetry or axis symmetry is formed on the second substrate layer, and a channel with a preset pattern of channels for the circulation of liquid medium is formed when the second substrate layer is bonded to the cathode layer. In this embodiment, by forming a channel for the circulation of liquid medium in the second substrate layer and the cathode layer, the heat generated when the diode is working can heat the liquid medium in the channel and increase the temperature, that is, the preset pattern can form a hot and cold temperature zone from the center to the edge with a central symmetry or axis symmetry, so that the liquid medium in the channel can circulate with different temperatures, and the liquid medium can take away the heat generated by the diode during the flow process, thereby reducing the temperature of the diode, ensuring the reliable operation of the diode, and helping to extend the life of the diode.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0020] Figure 1 is a schematic structural diagram of a diode according to an exemplary embodiment.

[0021] Figure 2 is a schematic structural diagram of another diode according to an exemplary embodiment.

[0022] Figure 3 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0023] Figure 4 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0024] Figure 5 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0025] Figure 6 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0026] Figure 7 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0027] Figure 8 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0028] Fig. 9 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0029] Fig.10 is a schematic structural diagram of yet another diode according to an exemplary embodiment.

[0030] Fig.11 The figure is a schematic diagram of the structure of a diode including a thermal conductive adhesive layer according to an exemplary embodiment.

[0031] Fig.12 The figure is a top view of a channel with a preset pattern that is symmetrical about a center or axis according to an exemplary embodiment.

[0032] Fig.13 is a schematic diagram showing the flow direction of a liquid medium in a channel of a preset pattern according to an exemplary embodiment.

[0033] Fig.14 is a schematic diagram showing the flow direction of a liquid medium in a channel of another preset pattern according to an exemplary embodiment.

[0034] Fig.15 The figure is a schematic diagram showing a valve disposed in a channel of a preset pattern according to an exemplary embodiment.

[0035] Fig.16 The diagram is a structural diagram of a photovoltaic module provided with a heat dissipation device according to an exemplary embodiment. DETAILED DESCRIPTION

[0036] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described exemplarily below do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices consistent with some aspects of the present disclosure as detailed in the attached claims. It should be noted that the features in the following embodiments and implementations may be combined with each other without conflict.

[0037] The present disclosure provides a diode, such as Figure 1As shown, it includes an anode layer 11, a first substrate layer 12, a cathode layer 13 and a second substrate layer 15 arranged in sequence. The anode layer 11 and the cathode layer may have impurities with different doping concentrations to show corresponding polarities. A buffer layer 14 is provided in the cathode layer 13 and is bonded to the first substrate layer 12; the buffer layer 14 includes a plurality of buffer regions; the material in each buffer region is the same as that in the anode layer 11, and the doping concentration of each buffer region is less than the doping concentration of the anode layer and greater than the doping concentration of the first substrate layer 12.

[0038] When a positive voltage and a negative voltage are applied to the anode layer 11 and the cathode layer 13 of the diode provided in this embodiment, a forward electric field can be established between the anode layer 11 and the cathode layer 13. The forward electric field enables electrons to move freely from the cathode layer 13 to the anode layer 11, thereby forming a current from the positive electrode to the negative electrode, that is, the diode is in a forward conduction state. When a negative voltage and a positive voltage are applied to the anode layer 11 and the cathode layer 13 of the diode, a reverse electric field can be established between the anode layer 11 and the cathode layer 13, see Figure 2 , the reverse electric field will prevent electrons from moving from the cathode layer 13 to the anode layer 11; thus, the voltage difference between the anode layer 11 and the cathode layer 13 needs to reach a preset voltage before the reverse electric field can be broken down, so that the diode is in a (recoverably) reverse conduction state.

[0039] Considering that in the reverse recovery process after the conduction process of the diode, especially the high-voltage diode, due to the existence of the above-mentioned reverse electric field, especially the strong electric field formed between the cathode layer 13 and the first substrate layer 12, the electrons will move from the anode layer 11 to the anode layer 11 to generate a secondary avalanche; in the secondary avalanche process, the collision of electrons and holes will release a large amount of energy, making it impossible for the diode to dissipate heat in time, thereby burning the diode. In this embodiment, by providing a buffer layer 14 between the anode layer 11 and the first substrate layer 12, a large number of holes can be injected into the first substrate layer 12 during the secondary avalanche, thereby weakening the strong electric field formed between the cathode layer 13 and the first substrate layer 12, reducing the energy released by the collision of electrons and holes, and then reducing the temperature of the diode, ensuring that the diode works normally and reliably, which is conducive to extending the service life of the diode.

[0040] Considering that diodes are usually used in AC circuits, there may be a skin effect in the current of the diode, that is, the current at the edge of the diode will be greater than the current in the central area, or in other words, the number of electrons at the edge of the diode will be greater than the number of electrons in the central area. For this reason, see Figure 3, in this embodiment, the thickness d of multiple buffer regions increases from the inside to the outside. That is to say, when the doping concentration of the buffer region is the same or similar (less than a preset threshold), the smaller the thickness of the buffer region, the fewer holes will be provided, that is, the closer the buffer region is to the center, the weaker the ability to relieve strong electric fields is, and the closer it is to the outside, the stronger the ability to relieve strong electric fields is, so that the center and outer regions of the diode generate less heat to avoid burning the diode. In one example, the thickness of multiple buffer regions can be set to 0.1 to 0.5 microns. For example, from the central area to the outer area, the thickness of the buffer region can be 0.1 micron, 0.2 micron, 0.3 micron, 0.4 micron and 0.5 micron, and the use of a stepped thickness can facilitate production and manufacturing. Moreover, in this example, the thickness of each buffer region can also be reduced by setting multiple buffer regions.

[0041] In one embodiment, considering that the holes provided by the buffer region increase from the inside to the outside, the area of ​​the buffer region can be adjusted in this embodiment, see Figure 4 , that is, the areas of the multiple buffer regions are gradually increased from the inside to the outside, so as to adjust the buffer regions to provide different numbers of holes, so as to achieve the effect of weakening the strong electric field between the cathode layer 13 and the first substrate layer 12. In one example, the area of ​​the buffer region can be 1 to 100 square microns, such as 10 square microns, 20 square microns, 30 square microns, 40 square microns, 50 square microns, 60 square microns, 70 square microns, 80 square microns, 90 square microns and 100 square microns, which can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of the present disclosure.

[0042] In another embodiment, the voids provided by the buffer region increase when expanding from the inside to the outside. In the case where the thickness of the plurality of buffer regions increases from the inside to the outside and / or the area increases from the inside to the outside, see Figure 5 In this embodiment, the doping concentration of multiple buffer regions can be the same, so that it is convenient to form the buffer region in one process and improve the yield. In this embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm 3 In one example, the concentrations in the buffer region are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of this disclosure.

[0043] In another embodiment, the increase in the voids provided by the buffer region is considered when expanding from the inside to the outside. In the case where the thickness of the plurality of buffer regions increases from the inside to the outside and / or the area increases from the inside to the outside, see Figure 6 In this embodiment, the doping concentration of multiple buffer regions also increases from the inside to the outside (the darker the color, the higher the doping concentration). Multiple buffer regions can provide more and more holes from the inside to the outside to facilitate the rapid mitigation of strong electric fields. In this embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm 3 In one example, the concentrations in the buffer region are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of this disclosure.

[0044] It is understandable that, considering that the thickness, area and / or doping concentration of multiple buffer regions are different, multiple processes can be used to form the buffer region to ensure that the buffer region meets the requirements. It should be noted that the thickness, area and / or doping concentration of the buffer region can refer to the contents of the above embodiments, and the combined solution falls within the scope of protection of the present disclosure.

[0045] In another embodiment, considering that the voids provided by the buffer region increase when expanding from the inside to the outside, when the thickness of each buffer region is the same, see Figure 7 , the areas of multiple buffer regions increase from the inside to the outside, so that the buffer regions away from the center provide more holes to facilitate the rapid mitigation of strong electric fields. In one example, the area of ​​the buffer region can be 1 to 100 square microns, such as 10 square microns, 20 square microns, 30 square microns, 40 square microns, 50 square microns, 60 square microns, 70 square microns, 80 square microns, 90 square microns and 100 square microns, which can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of the present disclosure. It is understandable that, considering that the thickness of multiple buffer regions is the same, multiple buffer regions can be formed by a one-time (mask) process, thereby improving the yield.

[0046] In another embodiment, when the thickness of the plurality of buffer regions is the same and the area increases from the inside to the outside, see Figure 8 , the doping concentration of each buffer region in the multiple buffer regions is the same, so that the buffer regions can be formed in the same process, thereby improving productivity and yield. In this embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm3 In one example, the concentrations in the buffer region are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of this disclosure.

[0047] In another embodiment, when the thickness of the plurality of buffer regions is the same and the area increases from the inside to the outside, see Fig. 9 The doping concentration of the multiple buffer regions increases from the inside to the outside, so that the buffer regions at different positions can provide different numbers of holes, which is conducive to weakening the strong electric field between the cathode layer 13 and the first substrate layer 12. In this embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm 3 In one example, the concentrations in the buffer region are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , can be selected according to the specific scenario, and the corresponding scheme falls into the protection scheme of this disclosure.

[0048] In one embodiment, considering that the diode releases a large amount of heat during the reverse recovery process, an arc groove may be provided at the edge of the PN junction formed by the anode layer 11 and the first substrate layer 12, such as Fig.10 In other words, since the arc-shaped groove 16 is provided at the PN junction formed by the anode layer 11 and the first substrate layer 12, a protruding structure 17 is formed at the PN junction formed by the cathode layer 13 and the first substrate layer 12, and the protruding structure 17 can increase the surface area of ​​the PN junction, thereby facilitating and accelerating the release of heat and preventing the diode from being burned out.

[0049] In one example, a layer of thermal conductive adhesive 18 is formed on the side of the diode where the protruding structure 17 is provided. Fig.11 The thermally conductive adhesive layer 18 is first bonded to the protruding structure 17 and then solidified, and is used to transfer the heat on the protruding structure 17. In this example, the thermally conductive adhesive layer 18 can extend to one side of the second substrate layer 15, reducing the alignment requirements for manufacturing and increasing the heat dissipation area. During packaging, an opening area can be formed on the package, and the thermally conductive adhesive layer 18 can be aligned with the opening area of ​​the package, so that a heat sink can be formed on the thermally conductive adhesive layer 18, which is conducive to accelerating heat dissipation.

[0050] Considering that the diode releases heat during operation and reverse recovery, which increases the temperature of the diode, the diode in this embodiment includes a second substrate layer 15, which is attached to the anode layer 11. A channel with a preset pattern is formed on the second substrate layer 15, and the preset pattern is symmetrical about the center or axis. Taking the axisymmetric preset pattern as an example, Fig.12 , Fig.13 and Fig.14 As shown, the preset pattern can be a radial wheel-type channel, in which the center portion 1211 and the edge portion 1213 of the wheel-type channel are provided with vias, and the connecting portion 1212 of the wheel-type channel is used to connect the center portion 1211 and the edge portion 1213, and the center portion 1211 and the edge portion 1213 are connected by a blind hole or a channel.

[0051] In one example, see Fig.13 During the reverse recovery process, the temperature of the center of the diode rises, and the temperature rise of the center portion 1211 will be greater than the temperature rise of the edge portion 1213. The temperature pressure difference formed can make the liquid medium flow downward through the center portion 1211, while the liquid medium in the edge portion 1213 flows upward, thereby reducing the temperature of the center portion 1211.

[0052] In another example, see Fig.14 , the inner diameters of the center portion 1211 and the edge portion 1213 can be adjusted, and the temperature and pressure difference can make the liquid medium flow upward through the center portion 1211, while the liquid medium in the edge portion 1213 flows downward. In this way, since the liquid medium with a lower temperature is directly aligned with the position where the diode has a higher temperature, the temperature of the center portion 1211 can be quickly reduced to avoid damage to the diode.

[0053] In one example, the diode further includes a valve 19 disposed in the channel. Fig.15 The valves 19 are respectively arranged inside the central part 1211 and the edge part 1213 to control the flow direction of the liquid medium. When the liquid medium flows in a preset direction, the valve 19 allows the liquid medium to pass through. When the liquid medium flows in the reverse direction of the preset direction, the valve 19 blocks the liquid medium from flowing, thereby achieving the effect of controlling the flow direction of the liquid medium.

[0054] It is understandable that the above embodiments describe the case where the inner diameters of the grooves (or channels) in the preset pattern are the same. In practical applications, the inner diameters of the grooves (or channels) may be different. In one example, the inner diameter of the channel of the preset pattern becomes larger and larger in the preset flow direction, thereby reducing the resistance to the flow of the liquid medium, which is conducive to increasing the flow speed of the liquid medium and ensuring the heat dissipation efficiency.

[0055] In one embodiment, the present disclosure also provides a photovoltaic module, the photovoltaic module comprising: Figure 1 to Figure 15 The above-mentioned photovoltaic module can be used in equipment such as frequency converters, inverters, converters, and transformers.

[0056] In one example, the photovoltaic module further includes a heat dissipation device 20. Fig.16 The heat sink is provided with an insertion port, and the pins of the center portion 1211 and the edge portion 1213 are inserted into the above-mentioned insertion port, so that the liquid medium in the channel circulates with the liquid medium in the heat sink 20 to achieve the effect of heat dissipation. Those skilled in the art will easily think of other embodiments of the present disclosure after considering the specification and practicing the disclosure disclosed herein. The present disclosure is intended to cover any variations, uses or adaptive changes that follow the general principles of the present disclosure and include common knowledge or customary technical means in the technical field that are not disclosed in the present disclosure. The description and examples are to be regarded as exemplary only, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0057] It should be understood that the present disclosure is not limited to the exact structures that have been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A diode, characterized in that: It comprises an anode layer, a first substrate layer, a cathode layer and a second substrate layer which are arranged in sequence; a buffer layer which is bonded to the first substrate layer is arranged in the cathode layer; the buffer layer comprises a plurality of buffer regions; the material in each buffer region is the same as the material in the anode layer, and the doping concentration of each buffer region is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; a channel with a preset pattern which is symmetrical about the center or axis is formed on the second substrate layer, and a channel for the flow of a liquid medium is formed when the second substrate layer is bonded to the cathode layer.

2. The diode according to claim 1, characterized in that The channel of the preset pattern includes a central portion, an edge portion and a connecting portion; the central portion and the connecting portion are arranged using vias; the connecting portion is arranged using a blind hole for connecting the central portion and the connecting portion, so that the liquid medium in the central portion flows to the edge portion, or the liquid medium in the edge portion flows to the central portion.

3. The diode according to claim 2, characterized in that A valve is arranged in the central portion and / or the edge portion, and the valve is used to control the flow direction of the liquid medium; the valve is used to open when the flow direction of the liquid medium is the same as the preset direction and close when the flow direction of the liquid medium is opposite to the preset direction.

4. The diode according to claim 1, characterized in that The diode further comprises an arc-shaped groove, which is arranged at the edge of the PN junction formed by the anode layer and the first substrate layer; and a protruding structure is formed at the PN junction formed by the cathode layer of the diode and the first substrate layer; The diode further comprises a heat-conducting adhesive layer, which is arranged on one side of the protruding structure and is used for conducting heat at the protruding structure.

5. The diode according to claim 4, characterized in that The thermal conductive adhesive layer is extended to a channel with a preset pattern on one side of the second substrate layer.

6. The diode according to claim 1, characterized in that The thickness of the plurality of buffer regions increases sequentially from the inside to the outside, and / or the area of ​​the plurality of buffer regions increases sequentially from the inside to the outside.

7. The diode according to claim 6, characterized in that The doping concentration of each buffer region among the plurality of buffer regions is the same, or the doping concentration of the plurality of buffer regions increases sequentially from the inside to the outside.

8. The diode according to claim 1, characterized in that The areas of the plurality of buffer regions increase sequentially from the inside to the outside.

9. The diode according to claim 8, characterized in that The doping concentration of each buffer region among the plurality of buffer regions is the same, or the doping concentration of the plurality of buffer regions increases sequentially from the inside to the outside.

10. A photovoltaic module, characterized in that: Comprising the diode according to any one of claims 1 to 9.

11. The photovoltaic module according to claim 10, characterized in that: It also includes a heat dissipation device; the heat dissipation device is provided with an insertion port; the channel of the preset pattern includes a central portion and an edge portion, and the pins of the central portion and the edge portion are inserted into the insertion port to circulate the liquid medium in the heat dissipation device and the liquid medium in the groove of the preset image.

Images