Diodes and photovoltaic modules

Abstract

This disclosure relates to a diode and a photovoltaic module. The diode includes a second substrate layer, an anode layer, a first substrate layer, and a cathode layer disposed sequentially. A buffer layer is disposed within the cathode layer and bonded to the first substrate layer. The buffer layer includes multiple buffer regions. The material in each buffer region is the same as that 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. Channels with a predetermined pattern of centrosymmetry or axial symmetry are formed on the second substrate layer, forming a channel for the flow of a liquid medium when the second substrate layer is bonded to the cathode layer. In this embodiment, the liquid medium can carry away the heat generated by the diode during flow, which helps to reduce the internal temperature of the diode and ensure reliable operation.

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

[0002] When the reverse voltage of the PN junction in the diode increases, the electric field in the space charge region is enhanced. The energy obtained by the electrons and holes passing through the space charge region under the action of the electric field increases, and the electrons and holes moving in the crystal will continuously collide with the atoms of the crystal. When the energy of the electrons and holes is large enough, the collision can excite the electrons in the covalent bond to form a free electron-hole pair. This phenomenon is called impact 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, re-obtain energy, and can generate electron-hole pairs again through collision. 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 snow-covered hill. The increase of carriers is fast and large, which makes the reverse current increase sharply, and thus the PN junction occurs avalanche breakdown.

[0003] However, as the voltage requirement of the diode is higher and higher (such as 2000V or more), the diode will have a secondary avalanche. That is, due to the strong electric field near the NN+ junction caused by avalanche electrons, the diode will have a secondary avalanche near the NN+ junction. At this time, the diode will pass a large current instantaneously and generate 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

[0004] The present disclosure provides a diode and a photovoltaic module to solve the problems 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; the cathode layer is provided with a buffer layer attached to the first substrate layer; the buffer layer comprises a plurality of buffer regions; the material in each buffer region is the same as that in the anode layer, and the doping concentration of each buffer region is less than that of the anode layer and greater than that of the substrate layer; a channel of a preset pattern which is centrally or axially symmetric is formed on the second substrate layer, and the second substrate layer is attached to the cathode layer to form a channel for the flow of a liquid medium.

[0006] Optionally, the channel of the preset pattern comprises a central part, an edge part and a connecting part; the central part and the connecting part are provided with through holes; the connecting part is provided with a blind hole for connecting the central part and the edge part, so that the liquid medium in the central part flows to the edge part, or the liquid medium in the edge part flows to the central part.

[0007] Optionally, the center part and / or the edge part is provided with a valve for controlling the flow direction of the liquid medium; the valve is opened when the flow direction of the liquid medium is the same as the preset direction and closed when the flow direction of the liquid medium is opposite to the preset direction.

[0008] Optionally, the diode further comprises an arc-shaped groove provided at the edge of the PN junction formed by the anode layer and the first substrate layer; the cathode layer of the diode and the first substrate layer form a protruding structure at the PN junction; the diode further comprises a heat-conducting glue layer provided at one side of the protruding structure for conducting heat at the protruding structure.

[0009] Optionally, the heat-conducting glue layer extends to one side of the second substrate layer.

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

[0011] Optionally, the doping concentration of each buffer region in the plurality of buffer regions is the same, or the doping concentration of the plurality of buffer regions gradually increases from inside to outside.

[0012] Optionally, the area of the plurality of buffer regions gradually increases from inside to outside.

[0013] Optionally, the doping concentration of each buffer region in the plurality of buffer regions is the same, or the doping concentration of the plurality of buffer regions gradually increases from inside to outside.

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

[0015] Optionally, further comprising a heat dissipation device; the heat dissipation device is provided with an insertion port; the preset pattern of grooves comprises a center part and an edge part, and the pins of the center part and the edge part are inserted into the insertion port to circulate the liquid medium in the heat dissipation device and the liquid medium in the preset pattern of grooves.

[0016] The technical solutions provided by the embodiments of the present disclosure can include the following beneficial effects:

[0017] The diode provided by the embodiments of the present disclosure can include an anode layer, a first substrate layer, a cathode layer and a second substrate layer arranged in sequence; the cathode layer is provided with a buffer layer attached to the first substrate layer; the buffer layer includes a plurality of buffer areas; the material in each buffer area is the same as that in the anode layer, and the doping concentration of each buffer area is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; the second substrate layer is formed with a channel of a preset pattern of central symmetry or axial symmetry, and the channel of the preset pattern of channel for the liquid medium to flow is formed when the second substrate layer is attached to the cathode layer. In this embodiment, the channel for the liquid medium to flow is formed in the second substrate layer and the cathode layer, and the heat generated during the operation of the diode can heat the liquid medium in the channel to increase the temperature, that is, the preset pattern of central symmetry or axial symmetry can form a temperature cold-hot area from the center to the edge, so that the liquid medium in the channel can flow in a cycle with different temperatures, and the liquid medium can carry away the heat generated by the diode during the flow process, thereby reducing the temperature of the diode and ensuring the reliable operation of the diode, which is conducive to prolonging the service life of the diode.

[0018] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0019] The accompanying drawings, which are incorporated into and form part of the specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

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

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

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

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

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

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

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

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

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

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

[0030] Figure 11 is a structural diagram of a diode including a thermally conductive glue layer according to an exemplary embodiment.

[0031] Figure 12 is a top view of a channel of a preset pattern according to an exemplary embodiment.

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

[0033] Figure 14 is a diagram of a flow direction of a liquid medium in a channel of a preset pattern according to an exemplary embodiment.

[0034] Figure 15 is a diagram of a valve disposed in a channel of a preset pattern according to an exemplary embodiment.

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

[0036] The exemplary embodiments will be described in detail herein with reference to the attached drawings. The following description is made with reference to the accompanying drawings in which like reference numerals refer to like elements, unless the context of use indicates otherwise. The following description of exemplary embodiments is not representative of all embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus consistent with some aspects of the present disclosure as detailed in the appended claims. It is to be understood that the features of the following embodiments and implementations can be combined with each other, if not contradictory.

[0037] The present disclosure provides a diode, such as Figure 1As shown, the diode comprises, in sequence, an anode layer 11, a first substrate layer 12, a cathode layer 13 and a second substrate layer 15. The anode layer 11 and the cathode layer 13 can have different impurity doping concentrations to exhibit corresponding polarities. The cathode layer 13 is provided with a buffer layer 14 which is attached to the first substrate layer 12; the buffer layer 14 comprises a plurality of buffer regions; each buffer region has the same material as the anode layer 11, and the doping concentration of each buffer region is less than the doping concentration of the anode layer 11 and greater than the doping concentration of the first substrate layer 12.

[0038] After the anode layer 11 and the cathode layer 13 are respectively applied with positive voltage and negative voltage, a forward electric field can be established between the anode layer 11 and the cathode layer 13, which allows electrons to freely move from the cathode layer 13 to the anode layer 11, thereby forming a current from the positive electrode to the negative electrode, i.e. the diode is in a forward conduction state. When the anode layer 11 and the cathode layer 13 are respectively applied with negative voltage and positive voltage, a reverse electric field can be established between the anode layer 11 and the cathode layer 13, which prevents 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 is broken down, so that the diode is in a (reversible) reverse conduction state. Figure 2

[0039] Considering that, during the reverse recovery process after the conduction process, the diode, especially a high-voltage diode, will generate a secondary avalanche due to the existence of the reverse electric field, especially the strong electric field formed between the cathode layer 13 and the first substrate layer 12, which causes electrons to move from the anode layer 11 to the anode layer 11; the collision between electrons and holes during the secondary avalanche process releases a large amount of energy, which makes the diode unable to dissipate heat in time, thereby burning out the diode. In the present embodiment, the buffer layer 14 is arranged between the anode layer 11 and the first substrate layer 12, which can inject a large number of holes 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 between electrons and holes, and further reducing the temperature of the diode, so as to ensure the normal and reliable operation of the diode and prolong the service life of the diode.

[0040] Considering that the diode is usually used in an alternating current circuit, the current in the diode can have a skin effect, i.e. the current at the edge of the diode is greater than that in the central region, or in other words, the number of electrons at the edge of the diode is greater than that in the central region. For this reason, as shown in Figure 3 ​In the embodiment, the thicknesses d of the plurality of buffer regions gradually increase from the inside to the outside. That is, in the case where the doping concentrations of the buffer regions are the same or similar (less than a preset threshold), the smaller the thickness of the buffer region, the fewer holes provided, that is, the closer to the center of the buffer region, the weaker the ability to relieve the strong electric field, and the closer to the outside, the stronger the ability to relieve the strong electric field, so that less heat is generated in the center and the outside of the diode, and the diode is prevented from being burned out. In an example, the thicknesses of the plurality of buffer regions can be 0.1-0.5 microns. For example, from the center region to the outside region, the thicknesses of the buffer regions can be 0.1 microns, 0.2 microns, 0.3 microns, 0.4 microns and 0.5 microns, and the stepped thicknesses can facilitate production and manufacturing. In addition, in the example, the thicknesses of the plurality of buffer regions can be reduced by setting the plurality of buffer regions.

[0041] In an 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 the embodiment, as shown in Figure 4 That is, the areas of the plurality of buffer regions gradually increase from the inside to the outside, so as to adjust the number of holes provided by the buffer region, and weaken the strong electric field between the cathode layer 13 and the first substrate layer 12. In an example, the area of the buffer region can be 1-100 square microns, for example, 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 a specific scene, and the corresponding scheme falls within the protection scheme of the disclosure.

[0042] In another embodiment, considering that the holes provided by the buffer region increase from the inside to the outside. In the case where the thicknesses of the plurality of buffer regions gradually increase from the inside to the outside and / or the areas gradually increase, as shown in Figure 5 In the embodiment, the doping concentrations of the plurality of buffer regions can be the same, so as to facilitate the formation of the buffer region by one process, and improve the yield. In the embodiment, the doping concentration of the buffer region is 1e 13 / cm 17 / cm 3 In an example, the concentrations of the buffer regions are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , which can be selected according to a specific scene, and the corresponding scheme falls within the protection scheme of the disclosure.

[0043] In yet another embodiment, considering the increase of holes provided by the buffer region when expanding from inside to outside, in the case that the thicknesses of the plurality of buffer regions gradually increase from inside to outside and / or the areas gradually increase from inside to outside, referring to Figure 6 , the doping concentrations of the plurality of buffer regions in the embodiment also gradually increase from inside to outside (the color deepening represents the increase of the doping concentration), and the plurality of buffer regions can provide more and more holes from inside to outside to facilitate the rapid reduction of the strong electric field. In the embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm 3 . In an example, the doping concentrations of the buffer regions are 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , which can be selected according to specific scenarios, and the corresponding solutions fall within the protection scope of the present disclosure.

[0044] It can be understood that, considering the case that the thicknesses, areas and / or doping concentrations of the plurality of buffer regions are different, the buffer region can be formed by multiple processes to ensure that the buffer region meets the requirements. It should be noted that the thicknesses, areas and / or doping concentrations of the buffer region can refer to the contents of the above embodiments, and the combined solutions fall within the protection scope of the present disclosure.

[0045] In another embodiment, considering the increase of holes provided by the buffer region when expanding from inside to outside, in the case that the thicknesses of the plurality of buffer regions are the same, referring to Figure 7 , the areas of the plurality of buffer regions gradually increase from inside to outside, so that the buffer regions far from the center provide more holes to facilitate the rapid reduction of the strong electric field. In an example, the area of the buffer region can be 1-100 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 specific scenarios, and the corresponding solutions fall within the protection scope of the present disclosure. It can be understood that, considering that the thicknesses of the plurality of buffer regions are the same, the plurality of buffer regions can be formed by one (mask) process, thereby improving the yield.

[0046] In another embodiment, in the case that the thicknesses of the plurality of buffer regions are the same and the areas gradually increase from inside to outside, referring to Figure 8 , the doping concentrations of each of the plurality of buffer regions are the same, so that the buffer region can be formed by one process to improve the production rate and yield. In the embodiment, the doping concentration of the buffer region is 1e 13 ~1e 17 / cm3 In an example, the concentration of the buffer region is 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , which can be selected according to specific scenarios, and the corresponding scheme falls within the protection scheme of the present disclosure.

[0047] In another embodiment, when the thicknesses of the plurality of buffer regions are the same and the areas of the plurality of buffer regions are sequentially increased from the inside to the outside, referring to Figure 9 , the doping concentrations of the plurality of buffer regions are sequentially increased from the inside to the outside, so that the buffer regions at different positions can provide different amounts of holes, which is beneficial to weaken 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 an example, the concentration of the buffer region is 1e 13 / cm 3 , 1e 14 / cm 3 , 1e 17 / cm 3 , which can be selected according to specific scenarios, and the corresponding scheme falls within the protection scheme of the present disclosure.

[0048] In an embodiment, considering that a large amount of heat will be released during the reverse recovery process of the diode, an arc-shaped groove can be arranged at the edge of the PN junction formed by the anode layer 11 and the first substrate layer 12, as shown in Figure 10 . Alternatively, due to the arc-shaped groove 16 arranged at the PN junction formed by the anode layer 11 and the first substrate layer 12, a protruding structure 17 will be formed at the PN junction formed by the cathode layer 13 and the first substrate layer 12, which can increase the surface area of the PN junction, thereby facilitating the release of heat and avoiding the diode from being burned out.

[0049] In an example, one side of the diode provided with the protruding structure 17 is formed with a heat-conducting glue layer 18. Referring to Figure 11 , the heat-conducting glue layer 18 is formed by first being attached to the protruding structure 17 and then being solidified, and is used for transmitting the heat on the protruding structure 17. In this example, the heat-conducting glue layer 18 can extend to one side of the second substrate layer 15, which reduces the alignment requirement of the manufacturing and increases the heat dissipation area. When packaging, an opening area can be formed on the package, and the heat-conducting glue layer 18 can be aligned with the opening area of the package, so that a heat sink can be formed on the heat-conducting glue layer 18, which is beneficial to accelerate heat dissipation.

[0050] In the working process and the reverse recovery process, the diode releases heat to increase the temperature of the diode. In this embodiment, the diode comprises a second substrate layer 15 which is attached to the cathode layer 13. The second substrate layer 15 is provided with a preset pattern of channels which are symmetric about the center or an axis. Taking the preset pattern as an example of axis symmetry, as shown in Figure 12 、 Figure 13 and Figure 14 , the preset pattern can be a wheel-shaped channel which presents a radial pattern. The center part 1211 and the edge part 1213 of the wheel-shaped channel are provided with through holes, and the communication part 1212 of the wheel-shaped channel is used to connect the center part 1211 and the edge part 1213, and the center part 1211 and the edge part 1213 are connected by blind holes or channels.

[0051] In an example, as shown in Figure 13 , the temperature of the center part 1211 increases more than the temperature of the edge part 1213 in the reverse recovery process, and the temperature pressure difference can make the liquid medium flow downward through the center part 1211 and upward through the edge part 1213, thereby reducing the temperature of the center part 1211.

[0052] In another example, as shown in Figure 14 , the inner diameters of the center part 1211 and the edge part 1213 can be adjusted, and the temperature pressure difference can make the liquid medium flow upward through the center part 1211 and downward through the edge part 1213. In this way, the temperature of the center part 1211 can be quickly reduced because the liquid medium with lower temperature directly targets the position with higher temperature of the diode, thereby avoiding damage to the diode.

[0053] In an example, the diode further comprises a valve 19 arranged in the channel. As shown in Figure 15 , the valve 19 is arranged in the inner part of the center part 1211 and the edge part 1213, respectively, for controlling the flow direction of the liquid medium. When the liquid medium flows in the preset direction, it can pass through, and when the liquid medium flows in the reverse direction of the preset direction, the valve 19 prevents the liquid medium from flowing, thereby achieving the effect of controlling the flow direction of the liquid medium.

[0054] It can be understood that the above examples describe the case where the inner diameters of the channels (or passages) in the preset pattern are the same. In actual applications, the inner diameters of the channels (or passages) in the preset pattern can be different. In an example, the inner diameters of the channels in the preset pattern increase in the preset flow direction, thereby reducing the resistance of the liquid medium flow, that is, it is beneficial to increase the flow speed of the liquid medium and ensure the heat dissipation efficiency.

[0055] In an embodiment, the present disclosure also provides a photovoltaic module which comprises a diode as described above.Figures 1 to 15 The diode. The photovoltaic module described above can be used in frequency converters, inverters, current converters, transformers, and the like.

[0056] In an example, the photovoltaic module described above further comprises a heat dissipation device 20. Referring to Figure 16 The heat dissipation device is provided with an insertion port, and the pins of the central portion 1211 and the edge portion 1213 are inserted into the insertion port, so that the liquid medium in the channel circulates with the liquid medium in the heat dissipation device 20, achieving the effect of heat dissipation. Other embodiments of the present disclosure will be readily apparent to those skilled in the art with the disclosure herein in conjunction with the description and practice thereof. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure following, in general, the principles of the present disclosure and including such

[0057] It should be understood that the present disclosure is not limited to the precise structures described above and illustrated in the drawings and that various modifications and changes can be made without departing from its scope. The scope of the present disclosure is limited only by the claims that follow.

Claims

1. A diode, characterized by, The diode comprises an anode layer, a first substrate layer, a cathode layer and a second substrate layer arranged in sequence; the cathode layer is provided with a buffer layer adhered to the first substrate layer; the buffer layer comprises a plurality of buffer areas; the material in each buffer area is the same as that in the anode layer, and the doping concentration of each buffer area is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; the second substrate layer is provided with a channel of a preset pattern which is central-symmetrical or axis-symmetrical, and the second substrate layer forms a channel for liquid medium to flow when adhered to the cathode layer; The channel of the preset pattern comprises a central part, an edge part and a connecting part; the central part and the connecting part are provided with through holes; the connecting part is provided with a blind hole for connecting the central part and the edge part, so that the liquid medium in the central part flows to the edge part or the liquid medium in the edge part flows to the central part; A heat dissipation device on the photovoltaic module composed of the diode circulates the liquid medium in the heat dissipation device and the liquid medium in the channel of the preset pattern; The heat dissipation device is provided with an insertion port; the pins of the central part and the edge part are inserted into the insertion port.

2. The diode of claim 1, wherein The central part and / or the edge part are provided with a valve for controlling the flow direction of the liquid medium; the valve opens when the flow direction of the liquid medium is the same as the preset direction and closes when the flow direction of the liquid medium is opposite to the preset direction.

3. The diode of claim 1, wherein The diode further comprises an arc-shaped groove arranged at the edge of the PN junction formed by the anode layer and the first substrate layer; and the PN junction of the cathode layer of the diode and the first substrate layer forms a protruding structure; The diode further comprises a heat-conducting adhesive layer arranged on one side of the protruding structure for conducting heat at the protruding structure.

4. The diode of claim 3, wherein The heat-conducting adhesive layer extends to the channel of the preset pattern on one side of the second substrate layer.

5. The diode of claim 1, wherein The thickness of the plurality of buffer areas gradually increases from inside to outside, and / or the area of the plurality of buffer areas gradually increases from inside to outside.

6. The diode of claim 5, wherein The doping concentration of each buffer area in the plurality of buffer areas is the same, or the doping concentration of the plurality of buffer areas gradually increases from inside to outside.

7. The diode of claim 1, wherein The area of the plurality of buffer areas gradually increases from inside to outside.

8. The diode of claim 7, wherein The doping concentration of each buffer area in the plurality of buffer areas is the same, or the doping concentration of the plurality of buffer areas gradually increases from inside to outside.

9. A photovoltaic module characterized by, The diode comprises an anode layer, a first substrate layer, a cathode layer and a second substrate layer arranged in sequence; the cathode layer is provided with a buffer layer adhered to the first substrate layer; the buffer layer comprises a plurality of buffer areas; the material in each buffer area is the same as that in the anode layer, and the doping concentration of each buffer area is less than the doping concentration of the anode layer and greater than the doping concentration of the substrate layer; the second substrate layer is provided with a channel of a preset pattern which is central-symmetrical or axis-symmetrical, and the second substrate layer forms a channel for liquid medium to flow when adhered to the cathode layer;

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