Infrared light cell array and preparation method and application thereof
By using step-like substrate assisted welding in the preparation of infrared photovoltaic cell arrays, the problem of arrays that cannot be repaired and expanded in the prior art is solved, and higher repairability and ductility are achieved.
Patent Information
- Application Number
- CN202411660716.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-04-01
AI Technical Summary
Existing infrared photovoltaic cell arrays cannot be repaired in the presence of damaged or low-performance battery devices, and the number of batteries cannot be increased or decreased according to the prototype size, resulting in poor repairability and ductility.
The step-like substrate assists welding is adopted. By gradually adding negative electrodes, photovoltaic cells and positive electrodes, and coating low-temperature tin slurry, the flexible welding and separation of the battery array is achieved, making it easy to repair and expand.
It improves the repairability and ductility of infrared photovoltaic cell arrays, can flexibly increase and decrease the number of batteries, and reduces battery damage rate and system costs.
Smart Images
Figure CN119744016A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of infrared photocells, and in particular to an infrared photocell array, a preparation method and application thereof. Background Art
[0002] The radioactive thermophotovoltaic (RTPV) system converts the kinetic energy of the energetic particles of radioactive isotopes into thermal energy, causing the emitter to generate high temperatures and emit infrared radiation. The infrared radiation then converts the decay energy into electrical energy through some semiconductor infrared photovoltaic conversion devices with specific bandgap widths, such as GaSb, InGaAs, GaAs, InGaAsSb, InAsSbP, etc. The theoretical efficiency of thermoelectric conversion in the thermophotovoltaic system can reach more than 20%. In addition to the high energy density, long life, and strong anti-interference characteristics of general isotope power sources, this technology also has outstanding technical advantages such as high energy conversion rate, high specific power, wide power range, no moving parts, small size and light weight, and multi-task adaptation. It is very suitable for the technical requirements of power systems required in the field of deep space and ocean exploration. The welding method of the infrared photovoltaic cell array in the RTPV system greatly affects the receiving efficiency of the infrared light emitted by the selective emitter, which in turn affects the utilization efficiency of the heat source isotope material, increasing the cost of the radioactive heat source material. In the preparation method of this type of infrared photovoltaic cell array, the positive and negative electrodes of the cell are basically welded by soldering, and the array is directly welded on a substrate such as SiC, AlSiC, Al, etc. The array and the substrate are used as a photovoltaic device in the RTPV system. Existing photovoltaic cell arrays usually connect GaSb photovoltaic cells in series into a group, and the two groups of cells are connected in parallel through bypass diodes, and the array is assembled on an aluminum backplane. When there are damaged or low-performance battery devices in the array, they cannot be repaired, and the number of cells cannot be increased or decreased according to the size of the prototype, and the maintainability and scalability are poor. Summary of the invention
[0003] The present application provides an infrared photocell array, a preparation method and application thereof, aiming to solve the above technical problems, improve the maintainability and scalability of the photovoltaic cell array, and have high practicality.
[0004] To this end, the present application proposes a method for preparing an infrared photocell array, comprising:
[0005] Use a stepped substrate to assist welding, wherein the two ends of the substrate are platforms, the middle of the substrate is a stepped area, the stepped planes are arranged parallel to each other, the length of the stepped plane is less than the length of the photovoltaic cell, and the step height is equal to the thickness of the photovoltaic cell;
[0006] Placing a negative electrode on the platform at one end of the substrate, and coating the edge of the negative electrode with low-temperature tin paste, then placing the photovoltaic cells in sequence, and coating the top electrode of each photovoltaic cell with the low-temperature tin paste, and then placing the positive electrode, and the battery array arrangement is completed;
[0007] After the substrate and the battery array are heated until the low-temperature solder paste is completely melted, the heating is stopped, the temperature is lowered to room temperature, and then the substrate and the battery array are separated to obtain the battery array.
[0008] Furthermore, the substrate is made of aluminum nitride.
[0009] Furthermore, the angle between the step plane and the horizontal is 5.5° to 6.0°.
[0010] Furthermore, the length of the stepped plane differs from the length of the photovoltaic cell by 1 mm to 1.5 mm.
[0011] Furthermore, before using the substrate, the substrate is cleaned and dried for later use.
[0012] Furthermore, the substrate and the battery array are fixedly connected by an adhesive.
[0013] Furthermore, the heating rate of the substrate and the battery array is ≤1°C / min, and when cooling, when the temperature is ≥50°C, the cooling rate is ≤1°C / min, and when the temperature is <50°C, the cooling rate is ≤2°C / min.
[0014] The present application proposes an infrared photovoltaic cell array, which is the cell array obtained by any of the above-mentioned methods for preparing infrared photovoltaic cell arrays, wherein the top electrodes and bottom electrodes of adjacent devices are connected by soldering. In the present application, the device refers to the negative electrode, photovoltaic cell and positive electrode in the cell array.
[0015] Furthermore, the number of the photovoltaic cells is 2 to 15.
[0016] The present application proposes the application of the above infrared photovoltaic cell array in a RTPV system, a concentrated thermal photovoltaic (CPV) system or a solar thermal photovoltaic (STPV) system.
[0017] The beneficial effects of this application are as follows:
[0018] The present application provides a method for preparing an infrared photovoltaic cell array, which uses a stepped substrate to assist welding, gradually adds negative electrodes, batteries and positive electrodes, and applies low-temperature tin paste, and obtains a fish-scale battery array after heating and cooling once. The preparation method is simple and controllable, and the number of steps of the substrate can be set according to the size or mode of the prototype to be suitable for welding different numbers of batteries. The preparation method of the present application is suitable for array welding of semiconductor infrared photovoltaic conversion devices such as GaSb, InGaAs, GaAs, InGaAsSb and InAsSbP.
[0019] In the prior art, the positive and negative electrodes of the battery are usually welded by soldering, and the array is directly welded on a substrate such as SiC, AlSiC, or Al. The array and the substrate as a whole are used as a photovoltaic device in the RTPV system. When there are damaged or low-performance battery devices in the array, they cannot be repaired. In the preparation method of the present application, the substrate and the battery array can be separated, so that the number of batteries in the battery array can be flexibly increased or decreased. Furthermore, the batteries in the original array can be replaced, making it repairable and increaseable. The preparation method of the present application can not only be used in RTPV systems, but can also be extended to various types of infrared photovoltaic cell welding in TPV systems.
[0020] The present application provides an infrared photocell array, wherein the top electrodes and bottom electrodes of adjacent devices are connected by soldering, with no wires in between, arranged in a fish scale shape, having stable performance and a low cell damage rate.
[0021] The infrared photovoltaic cell array of the present application has high maintainability and scalability, good consistency, and can be widely used in systems such as RTPV, CPV or STPV. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is a schematic diagram of the GaSb photovoltaic cell structure.
[0023] Among them, 1 is the top electrode, 2 is p-GaSb, 3 is n-GaSb, and 4 is the bottom electrode.
[0024] Figure 2 Schematic diagram of the substrate of Example 1.
[0025] Figure 3 This is a schematic diagram of Example 1 after placing the negative electrode copper sheet.
[0026] Figure 4 This is a schematic diagram of Example 1 after the first photovoltaic cell is placed.
[0027] Figure 5 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the first photovoltaic cell in Example 1.
[0028] Figure 6 This is a schematic diagram of Example 1 after placing the second photovoltaic cell.
[0029] Figure 7 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the second photovoltaic cell in Example 1.
[0030] Figure 8 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the ninth photovoltaic cell in Example 1.
[0031] Fig. 9 This is a schematic diagram of Example 1 after the tenth photovoltaic cell is placed.
[0032] Fig.10 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the tenth photovoltaic cell in Example 1.
[0033] Fig.11 This is a schematic diagram of Example 1 after placing the positive electrode copper sheet.
[0034] Fig.12 Schematic diagram of separation of the substrate and battery array in Example 1. DETAILED DESCRIPTION
[0035] The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present application, but should not be construed as limiting the present application. If no specific conditions are specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer shall be followed.
[0036] In this application, the step plane refers to the surface of the step used to place the device, and does not mean the position or shape of the surface. The step height refers to the distance between two adjacent step planes.
[0037] A method for preparing an infrared photocell array, comprising:
[0038] Clean the aluminum nitride substrate, clean the surface of the aluminum nitride substrate with anhydrous ethanol, dry it naturally, make sure there is no attachment or stain on the aluminum nitride surface, and set it aside after drying. The substrate is made of aluminum nitride, especially high-purity aluminum nitride, which has excellent thermal conductivity. During the welding process, the battery is heated evenly, and it is not easy to cause battery breakage due to large temperature gradients. It can enable photovoltaic cells to quickly dissipate heat in the TPV system; it has high mechanical strength, which can protect the battery array from bending and damage during the welding process; high-purity aluminum nitride powder has the characteristics of high purity, fine particle size and good sintering properties, which is crucial for the preparation of high-performance ceramic substrates.
[0039] A stepped substrate is used to assist welding. The two ends of the substrate are platforms, and the middle of the substrate is a stepped area. The stepped planes are arranged parallel to each other, and the angle between the stepped planes and the horizontal is 5.5° to 6.0°. The length of the stepped plane is less than the length of the photovoltaic cell, and the length of the stepped plane differs from the length of the photovoltaic cell by 1mm to 1.5mm. The height of the step is equal to the thickness of the photovoltaic cell.
[0040] A negative electrode is placed on the platform at one end of the substrate, and a low-temperature tin paste is coated on the edge of the negative electrode. The low-temperature tin paste in this application is also called low-temperature solder paste (Sn16 / Pb32 / Bi52 type). Then the photovoltaic cells are placed in sequence, each photovoltaic cell comprising a top electrode, p-GaSb, n-GaSb and a bottom electrode, such as Figure 1 As shown. The low-temperature tin paste is applied to the top electrode of each photovoltaic cell. Specifically, the first photovoltaic cell is placed, and the low-temperature tin paste is applied to the top electrode of the first photovoltaic cell; the above steps are repeated to place the second to the last photovoltaic cell in sequence, and the low-temperature tin paste is applied to the top electrode of each photovoltaic cell. Then the positive electrode is placed, and the battery array arrangement is completed.
[0041] The substrate and the battery array may be fixedly connected by an adhesive, and the adhesive is a thermally conductive adhesive.
[0042] Heat the substrate and the battery array to a temperature ≥ 96°C, preferably 98°C, with a heating rate ≤ 1°C / min. After the low-temperature tin paste is completely melted, stop heating. Cool down to room temperature, and the cooling process should be as slow as possible. When the temperature is ≥ 50°C, the cooling rate is ≤ 1°C / min, and when the temperature is < 50°C, the cooling rate is ≤ 2°C / min. If the heating rate is too fast or the cooling rate is too fast, the photovoltaic cells are easily broken due to uneven heating, which greatly reduces the performance of the battery array. Then separate the substrate and the battery array to obtain the battery array.
[0043] When the battery array needs to be repaired, the battery array and substrate, the normal battery to be replaced and the substrate are placed on the heating table respectively, the temperature is heated to 96°C, the problematic battery is removed and replaced with a normal battery, and low-temperature tin paste is applied to the top electrodes connected at both ends, the temperature is heated to 98°C, and after the tin paste is melted, it is then cooled to room temperature according to the normal welding cooling procedure mentioned above.
[0044] When it is necessary to increase or decrease the battery array, place the battery array and substrate, the battery to be welded and the new substrate on the heating table, heat the temperature to 96°C, remove the electrode or battery at one end, cool it down to 50°C, transfer the battery array to the new substrate, and apply low-temperature tin paste on the electrodes connected at both ends, heat the temperature to 98°C, wait for the tin paste to melt, and then cool it down to room temperature according to the normal welding cooling procedure mentioned above.
[0045] Conventional welding methods have the following disadvantages: soldering is used between the battery and the substrate, and the battery cannot be disassembled for repair or addition or removal. When a battery has a problem, the entire array will be unusable, resulting in waste; when applied to TPV systems, if traditional soldering is used between the battery and the substrate, its thermal conductivity is not high and the battery heat dissipation efficiency is not high; the thermal expansion coefficients of solder and battery are different. Due to the relatively tight connection, the battery is prone to breakage due to different thermal expansion when it is outputting high power.
[0046] An infrared photovoltaic cell array is the cell array obtained by any of the above-mentioned methods for preparing infrared photovoltaic cell arrays, wherein the top electrodes and bottom electrodes of adjacent devices are connected by soldering, without wires in between, and arranged in a fish scale shape. The infrared photovoltaic cells are directly connected without wires, which can reduce the internal resistance of the array, thereby reducing the internal loss of the cell array.
[0047] The number of photovoltaic cells is 2 to 15. Too many photovoltaic cells means that the heat source of the TPV system is larger, the difference in infrared light distribution at the edge and center of the surface is greater, and the output of the cells at the edge and the center of the same array is different, which ultimately makes the output of the entire array lower, and also causes the edge cells to have an over-discharge effect, damaging the cells.
[0048] Example 1
[0049] A method for preparing an infrared photocell array, comprising:
[0050] 1. Clean the aluminum nitride substrate, such as Figure 2 As shown, the surface of the aluminum nitride substrate is cleaned with anhydrous ethanol and dried naturally to remove any attachments, stains, etc. from the surface of the aluminum nitride. After drying, it is ready for use.
[0051] 2. Use a stepped substrate to assist welding. The two ends of the substrate are platforms, and the middle of the substrate is a stepped area. The stepped planes are parallel to each other, and the angle between the stepped plane and the horizontal is 5.5°. The length of the stepped plane is 15.5mm. The height of the step is equal to the thickness of the photovoltaic cell.
[0052] 3. Place the negative electrode copper sheet on the platform at one end of the substrate, and apply low-temperature tin paste on the edge of the negative electrode copper sheet, then place GaSb photovoltaic cells (16.5mm*11mm*1mm) in sequence, and apply low-temperature tin paste on the top electrode of each photovoltaic cell, and then place the positive electrode copper sheet, and the battery array is arranged. The battery array arrangement process is as follows Figures 3 to 11 As shown, Figure 3 This is a schematic diagram after placing the negative electrode copper sheet. Figure 4 This is a schematic diagram after placing the first photovoltaic cell. The yellow part marks the location of the top electrode. Figure 5This is a schematic diagram of coating low-temperature solder paste on the top electrode of the first photovoltaic cell, where the blue part is low-temperature solder paste. Figure 6 This is a schematic diagram after placing the second photovoltaic cell. Figure 7 Schematic diagram of coating low-temperature tin paste on the top electrode of the second photovoltaic cell, which is carried out in sequence. Figure 8 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the ninth photovoltaic cell. Fig. 9 This is a schematic diagram after placing the tenth photovoltaic cell. Fig.10 This is a schematic diagram of coating low-temperature tin paste on the top electrode of the tenth photovoltaic cell. Fig.11 This is a schematic diagram after placing the positive electrode copper sheet.
[0053] 4. Heat the substrate and battery array to 98°C with a heating table at a heating rate of 1°C / min. After all the low-temperature tin paste is melted, stop heating. When the heating table temperature is ≥50°C, cool down at a rate of 1°C / min. When the heating table temperature is <50°C, cool down at a rate of 2°C / min until it reaches room temperature. Then separate the substrate and battery array. Fig.12 As shown, a ten-cell battery array with electrodes is obtained.
[0054] Example 2
[0055] A method for preparing an infrared photocell array, comprising:
[0056] 1. Clean the aluminum nitride substrate, clean the surface of the aluminum nitride substrate with anhydrous ethanol, dry it naturally, so that there is no attachment, stains, etc. on the surface of the aluminum nitride, and set it aside after drying.
[0057] 2. Use a stepped substrate to assist welding. The two ends of the substrate are platforms, and the middle of the substrate is a stepped area. The stepped planes are parallel to each other, and the angle between the stepped plane and the horizontal is 6.0°. The length of the stepped plane is 15mm. The height of the step is equal to the thickness of the photovoltaic cell.
[0058] 3. Place a negative electrode copper sheet on the platform at one end of the substrate, and apply low-temperature tin paste on the edge of the negative electrode copper sheet. Then place the GaSb photovoltaic cells in sequence, and apply low-temperature tin paste on the top electrode of each photovoltaic cell. Then place the positive electrode copper sheet, and the battery array arrangement is completed.
[0059] 4. Heat the substrate and battery array to 99°C on a heating table at a heating rate of 1°C / min. After all the low-temperature tin paste is melted, stop heating. Cool down to room temperature at a cooling rate of 1°C / min. Then separate the substrate and battery array to obtain a 15-piece battery array with electrodes.
[0060] 5. Evenly mix high-purity aluminum nitride powder and vacuum thermal conductive silicone grease in a mass ratio of 1:2 to form a paste-like adhesive. Apply the adhesive evenly on the stepped surface of the substrate with a thickness of 0.2 mm. Then place the battery array on the substrate coated with the adhesive according to its position and press gently to ensure a firm bond.
[0061] In the description of the present application, it should be understood that the terms "length", "thickness", "upper", "horizontal", "top", "bottom", "edge", "two ends", "middle" and the like indicating positions or positional relationships are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present application. It is understood that those of ordinary skill in the art can change, modify, replace and modify the above embodiments within the scope of the present application without departing from the principles and purpose of the present application.
Claims
1. A method for preparing an infrared photocell array, characterized in that: include: Use a stepped substrate to assist welding, wherein the two ends of the substrate are platforms, the middle of the substrate is a stepped area, the stepped planes are arranged parallel to each other, the length of the stepped plane is less than the length of the photovoltaic cell, and the step height is equal to the thickness of the photovoltaic cell; Placing a negative electrode on the platform at one end of the substrate, and coating the edge of the negative electrode with low-temperature tin paste, then placing the photovoltaic cells in sequence, and coating the top electrode of each photovoltaic cell with the low-temperature tin paste, and then placing the positive electrode, and the battery array arrangement is completed; After the substrate and the battery array are heated until the low-temperature solder paste is completely melted, the heating is stopped, the temperature is lowered to room temperature, and then the substrate and the battery array are separated to obtain the battery array.
2. The method for preparing the infrared photocell array according to claim 1, characterized in that: The substrate is made of aluminum nitride.
3. The method for preparing the infrared photocell array according to claim 1, characterized in that: The angle between the step plane and the horizontal is 5.5° to 6.0°.
4. The method for preparing the infrared photocell array according to claim 1, characterized in that: The length of the step plane differs from the length of the photovoltaic cell by 1 mm to 1.5 mm.
5. The method for preparing the infrared photocell array according to claim 1, characterized in that: Before using the substrate, clean the substrate and dry it for later use.
6. The method for preparing the infrared photocell array according to claim 1, characterized in that: The substrate and the battery array are fixedly connected by an adhesive.
7. The method for preparing the infrared photocell array according to claim 1, characterized in that: The heating rate of the substrate and the battery array is ≤1°C / min. When cooling, when the temperature is ≥50°C, the cooling rate is ≤1°C / min, and when the temperature is <50°C, the cooling rate is ≤2°C / min.
8. An infrared photocell array, characterized in that: It is the battery array obtained by the method for preparing the infrared photocell array according to any one of claims 1 to 7, and the top electrodes and bottom electrodes of adjacent devices are connected by soldering.
9. The infrared photocell array according to claim 8, characterized in that: The number of the photovoltaic cells is 2 to 15.
10. Application of the infrared photocell array according to claim 8 or 9 in a radioactive thermophotovoltaic system, a concentrated thermal photovoltaic system or a solar thermal photovoltaic system.