Crystalline silicon solar cell, preparation method thereof and laminated cell

Abstract

The invention relates to a crystalline silicon solar cell, a preparation method thereof and a laminated cell. According to the crystalline silicon solar cell piece, a passivation layer is arranged on the crystalline silicon solar cell piece, and the passivation layer contains lanthanide series rare earth fluoride. According to the crystalline silicon solar cell, lanthanide series rare earth fluoride is used as a passivation material to passivate the polycrystalline silicon surface of the crystalline silicon solar cell, and particularly, secondary passivation is carried out on the cutting surface of the crystalline silicon solar cell of which the polycrystalline silicon material is exposed after cutting, so that a passivation layer is formed. Compared with a crystalline silicon battery piece which is not subjected to secondary passivation after cutting, the crystalline silicon solar battery piece with the lanthanide rare earth fluoride passivation layer has the advantages that the conversion efficiency is obviously improved, the filling factor FF and the open-circuit voltage Voc are also improved, and particularly after the crystalline silicon solar battery piece is combined and laminated with a perovskite battery to form a 4T laminated battery, the conversion efficiency of the crystalline silicon solar battery piece is greatly improved. And the conversion efficiency can be close to the efficiency before cutting.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a crystalline silicon solar cell sheet and a preparation method thereof, and a laminated cell. Background Art

[0002] At present, when photovoltaic new energy is widely used, the trend of thinning crystalline silicon solar cells is getting bigger and bigger. With the thinning of crystalline silicon solar cells, surface recombination has become a key factor affecting the efficiency of solar cells. Therefore, how to effectively reduce the surface recombination of thinned crystalline silicon solar cells becomes particularly important. Crystalline silicon surface passivation technology can effectively reduce the surface recombination rate, but silicon wafer cutting destroys this passivation layer. In the use of crystalline silicon, due to size matching and series connection problems, it is sometimes necessary to laser cut the entire piece of crystalline silicon. During the cutting process, new unpassivated edges will appear, causing edge recombination, which will lead to reduced efficiency of solar cells. Small-sized cells have a larger perimeter-to-area ratio, and edge recombination is more obvious, which will also cause the loss of open circuit voltage Voc and fill factor FF. Therefore, the edges of the cut crystalline silicon need to be passivated again.

[0003] In the existing scheme, the parameters of plasma enhanced chemical vapor deposition are difficult to control, which can easily affect the properties of the film during production; and although thermal oxidation growth of SiO2 passivation film achieves higher conversion efficiency, the high temperature time is too long and the operation is complicated, which can easily cause defects in the crystalline silicon substrate and reinforce the recombination, thereby resulting in a decrease in the minority carrier lifetime and affecting battery performance.

[0004] Therefore, it is necessary to study a method with simple process, significant effect, no influence on film properties and low cost to perform secondary passivation on the edges of cut crystalline silicon cells. Summary of the invention

[0005] Based on this, it is necessary to provide a crystalline silicon solar cell sheet and its preparation method, and a laminated cell to address the problems of poor effect, complex process, impact on film properties, and high cost of existing secondary passivation methods for cut surfaces of crystalline silicon cells.

[0006] A crystalline silicon solar cell sheet is provided with a passivation layer, and the passivation layer contains lanthanide rare earth fluoride.

[0007] The above-mentioned crystalline silicon solar cell uses lanthanum rare earth fluoride as a passivation material to passivate the polycrystalline silicon surface of the crystalline silicon solar cell, and in particular, the cut surface of the crystalline silicon solar cell that exposes the polycrystalline silicon material after cutting is subjected to secondary passivation to form a passivation layer. Compared with the crystalline silicon cell that has not been subjected to secondary passivation after cutting, the crystalline silicon solar cell with the lanthanum rare earth fluoride passivation layer has significantly improved conversion efficiency, fill factor FF and open circuit voltage. Voc They have also been improved, especially after being combined with perovskite cells and laminated to form 4T stacked cells, the conversion efficiency can be close to the efficiency before cutting.

[0008] In one of the embodiments, the crystalline silicon solar cell comprises a first electrode, a back surface field layer, a polysilicon layer, a front surface field layer, the passivation layer, and a second electrode stacked in sequence; the passivation layer is also arranged on the side surface of the crystalline silicon solar cell.

[0009] In one of the embodiments, the back surface field layer is a boron-doped emitter electrode layer, and the front surface field layer is a phosphorus-doped polysilicon layer.

[0010] In one embodiment, the crystalline silicon solar cell has at least one cutting surface, and the passivation layer is disposed on the cutting surface of the crystalline silicon solar cell.

[0011] In one embodiment, the lanthanide rare earth fluoride is neodymium fluoride.

[0012] In one embodiment, the thickness of the passivation layer is 0.001-0.01 μm.

[0013] In one embodiment, the thickness of the passivation layer is 0.003-0.009 μm.

[0014] In one embodiment, the thickness of the passivation layer is 0.003-0.007 μm.

[0015] In one embodiment, the purity of the neodymium fluoride is 99.99%.

[0016] The present invention also provides a method for preparing the crystalline silicon solar cell, comprising the following steps: passivation: depositing the lanthanide rare earth fluoride on the surface of the polysilicon layer and / or the surface of the front surface field layer and / or the surface of the back surface field layer of the crystalline silicon solar cell to form the passivation layer.

[0017] In one of the embodiments, the method for preparing the crystalline silicon solar cell comprises the following steps: cutting: cutting a large crystalline silicon cell according to a preset area to obtain a plurality of small crystalline silicon cells; passivation: depositing the lanthanide rare earth fluoride on the cut surface of the small crystalline silicon cell to form the passivation layer.

[0018] In one embodiment, the large crystalline silicon cell is a topcon crystalline silicon cell or a HJT crystalline silicon cell.

[0019] In one of the embodiments, the large crystalline silicon cell is a topcon crystalline silicon cell.

[0020] In one embodiment, the specific method of deposition is evaporation, and the conditions of evaporation are: vacuum degree 1.0×10 -4 ~1.0×10 -3 Pa, temperature 1500~1900℃, time ≤10min.

[0021] The above-mentioned method for preparing crystalline silicon solar cells is simple and easy to operate, the parameter coefficients are easy to control, and the high-temperature evaporation time does not exceed 10 minutes. It can effectively prevent the high temperature time from being too long, causing defects in the crystalline silicon substrate, and the occurrence of situations such as enhanced recombination, which leads to a decrease in minority carrier lifetime and affects battery performance.

[0022] In one embodiment, the evaporation conditions also include: current 120~170A, rate 0.01~0.02A / s.

[0023] In one of the embodiments, the method for preparing the crystalline silicon solar cell further comprises a vacuuming step after the deposition step, wherein the vacuuming condition is: making the vacuum degree reach 10-90 kPa at a temperature of 100-150° C. and maintaining it for more than 250 seconds.

[0024] The present invention also provides a stacked battery, comprising the crystalline silicon solar cell sheet as described above.

[0025] In one of the embodiments, the tandem cell is a crystalline silicon-perovskite tandem cell, including at least one perovskite sub-cell and at least one crystalline silicon sub-cell; the crystalline silicon sub-cell includes the crystalline silicon solar cell as described above.

[0026] The present invention also provides an application of the crystalline silicon solar cell sheet in preparing a power generation device and / or an energy storage device and / or an electrical device.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The crystalline silicon solar cell and its preparation method and laminated cell of the present invention use lanthanum rare earth fluoride as a passivation material to passivate the polycrystalline silicon surface of the crystalline silicon solar cell, especially to perform secondary passivation on the cut surface of the crystalline silicon solar cell that exposes the polycrystalline silicon material after cutting to form a passivation layer. Compared with the crystalline silicon cell that has not been subjected to secondary passivation after cutting, the crystalline silicon solar cell with the lanthanum rare earth fluoride passivation layer has significantly improved conversion efficiency, fill factor FF and open circuit voltage. V ocThe conversion efficiency of the crystalline silicon solar cell is close to that before cutting, especially after being combined with the perovskite cell and laminated to form a 4T stacked cell. The preparation method of the crystalline silicon solar cell of the present invention is simple and easy to operate, the parameter coefficient is easy to control, and the high-temperature evaporation time does not exceed 10 minutes, which can effectively prevent the high-temperature time from causing defects in the crystalline silicon substrate, and the occurrence of the situation that the composite is strengthened, thereby reducing the minority carrier lifetime and affecting the battery performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a crystalline silicon solar cell having a passivation layer disposed on the side surface and / or the cut surface in the present invention;

[0030] Figure 2 It is a schematic diagram of a crystalline silicon solar cell provided with a passivation layer in the present invention. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0033] The reagents used in the following examples, unless otherwise specified, are all commercially available; the methods used in the following examples, unless otherwise specified, are all achievable by conventional methods.

[0034] Example 1

[0035] A crystalline silicon solar cell having a structure as Figure 2 As shown, it includes a first electrode, a back surface field layer, a polysilicon layer, a front surface field layer, a passivation layer, and a second electrode stacked in sequence; the passivation layer is also arranged on the side surface of the crystalline silicon solar cell. Among them, the back surface field layer is a boron-doped emitter electrode layer, and the front surface field layer is a phosphorus-doped polysilicon layer.

[0036] Example 2

[0037] A crystalline silicon cell having a 0.003 μm thick passivation layer on the cut surface was prepared.

[0038] The preparation method comprises the following steps:

[0039] (1) Pretreatment: Cut large crystalline silicon cells (JA Topcon, 199 cm × 182 cm) into small crystalline silicon cells (16 cm 2 ); Rinse the cut surface with 99.8% ethanol to obtain the crystalline silicon cell to be passivated.

[0040] (2) Passivation: A 0.03 μm thick neodymium fluoride passivation layer (the neodymium fluoride target material was purchased from McLean, with a purity of 99.99% and a CAS number of 13709-42-7) was deposited on the cut surface after the above pretreatment by evaporation to obtain a passivated crystalline silicon cell.

[0041] The conditions for evaporation are: vacuum degree 1.0×10 -3 Pa, temperature 1500℃~1900℃, current maintained at 120~170A, rate 0.01~0.02Å / s. Under this condition, the evaporation time does not exceed 10min.

[0042] (3) Welding: Soldering tinned copper strip electrodes onto the above passivated crystalline silicon cell to obtain a welded crystalline silicon cell.

[0043] (4) Lamination: Cut out the edge of the crystalline silicon and the bottom glass of 2 cm, and then cut out 2 sheets of POE film and 2 sheets of PET plastic film of the same size as the bottom glass; stack and fix them in the order of bottom glass, POE film, passivated crystalline silicon cell, POE film, PET plastic film (frosted side down), PET plastic film (smooth side down, to be torn off after lamination); put them into the laminator and laminate them.

[0044] The lamination conditions are as follows: temperature is 110°C; vacuum: vacuum degree 60kPa (the pressure applied on the surface of the crystalline silicon cell is 40kPa), hold for 50s; vacuum degree 30kPa (the pressure applied on the surface of the crystalline silicon cell is 70kPa), hold for 50s; vacuum degree 10kPa (the pressure applied on the surface of the crystalline silicon cell is 90kPa), lamination for 350s.

[0045] Example 3

[0046] A crystalline silicon cell having a 0.005 μm thick passivation layer on the cut surface was prepared.

[0047] The preparation method is basically the same as that of Example 2, except that in step (2) passivation, a neodymium fluoride passivation layer with a thickness of 0.005 μm is deposited on the pretreated cut surface.

[0048] Example 4

[0049] A crystalline silicon cell having a passivation layer with a thickness of 0.007 μm on the cut surface was prepared.

[0050] The preparation method is basically the same as that of Example 2, except that in step (2) passivation, a neodymium fluoride passivation layer with a thickness of 0.007 μm is deposited on the pretreated cut surface.

[0051] Example 5

[0052] A 4T tandem cell (crystalline silicon-perovskite tandem cell) was prepared using a crystalline silicon cell with a 0.003 μm thick passivation layer as the bottom cell.

[0053] The preparation method comprises the following steps:

[0054] (1) Pre-processing: Cut the large crystalline silicon cell (JA Topcon 199cm×182cm) into small crystalline silicon cells (19.2cm 2 ); Rinse the cut surface with 99.8% ethanol to obtain the crystalline silicon cell to be passivated.

[0055] (2) Passivation: A neodymium fluoride passivation layer with a thickness of 0.03 μm is deposited on the cut surface after the above pretreatment by an evaporation method to obtain a passivated crystalline silicon cell.

[0056] The conditions for evaporation are: vacuum degree 1.0×10 -3 Pa, temperature 1500℃~1900℃, current maintained at 120~170A, rate 0.01~0.02Å / s. Under this condition, the evaporation time does not exceed 10min.

[0057] (3) Welding: Soldering tinned copper strip electrodes onto the above passivated crystalline silicon cell to obtain a welded crystalline silicon cell.

[0058] (4) Preparation of perovskite cells: Cut out a 7 cm × 7 cm bottom glass for use; deposit a PTAA hole transport layer, a perovskite layer (the band gap of perovskite is 1.5 eV), and a C 60 The electron transport layer and Cu electrode layer were used to obtain 21 cm 2 of perovskite batteries.

[0059] (5) Lamination: Place the perovskite cell with the film surface facing upward and apply a layer of 5mm*2mm*70mm butyl adhesive around the perovskite. Cut out three POE adhesive films and one PET plastic film with the same area as the butyl adhesive frame. Place the POE adhesive film, PET plastic film, POE adhesive film, and the bottom area of ​​19.2cm in the butyl adhesive frame. 2A crystalline silicon cell with a 0.003μm thick passivation layer (front side facing down) is placed on the original butyl rubber frame with a circle of butyl rubber (to fix the position of the crystalline silicon), and finally a layer of POE film is placed in it. The above-mentioned 7cm×7cm bottom glass is covered on the butyl rubber to overlap with the bottom ITO conductive glass, and then placed in a laminator for lamination.

[0060] The lamination conditions are as follows: temperature is 110°C; vacuum: vacuum degree 60kPa (the pressure applied on the surface of the crystalline silicon cell is 40kPa), hold for 50s; vacuum degree 30kPa (the pressure applied on the surface of the crystalline silicon cell is 70kPa), hold for 50s; vacuum degree 10kPa (the pressure applied on the surface of the crystalline silicon cell is 90kPa), lamination for 350s.

[0061] Example 6

[0062] A 4T tandem cell (crystalline silicon-perovskite tandem cell) was prepared using a crystalline silicon cell with a 0.005 μm thick passivation layer as the bottom cell.

[0063] The preparation method is basically the same as that of Example 5, except that in step (2) passivation, a neodymium fluoride passivation layer with a thickness of 0.005 μm is deposited on the pretreated cut surface.

[0064] Example 7

[0065] A 4T tandem cell (crystalline silicon-perovskite tandem cell) was prepared using a crystalline silicon cell with a 0.007 μm thick passivation layer as the bottom cell.

[0066] The preparation method is basically the same as that of Example 5, except that in step (2) passivation, a neodymium fluoride passivation layer with a thickness of 0.007 μm is deposited on the pretreated cut surface.

[0067] Experimental Example 1

[0068] A solar simulator (Newport Oriel ORIEL-SOI3A) was used to test the crystalline silicon cells at different stages in Examples 2 to 4 - the crystalline silicon cell to be passivated (before passivation), the crystalline silicon cell after passivation, and the crystalline silicon cell after lamination. The test results are shown in Tables 1 to 3. Compared with 0.003μm and 0.007μm, the efficiency of the crystalline silicon cell with a passivation layer of 0.005μm thick is the most improved, and the efficiency after lamination is also the most improved.

[0069]

[0070]

[0071]

[0072] Experimental Example 2

[0073] A solar simulator (Newport Oriel ORIEL-SOI3A) was used to detect the batteries in each step of Examples 5 to 7:

[0074] (1) Pre-passivation testing: Testing the crystalline silicon cell to be passivated; stacking the perovskite cell on the crystalline silicon cell to be passivated, and testing the performance of the perovskite cell (top of the stack) and the crystalline silicon cell (bottom of the stack) in the stacked state.

[0075] (2) Post-passivation testing: Testing the crystalline silicon cell after passivation; stacking the perovskite cell on the passivated crystalline silicon cell, and testing the performance of the perovskite cell (top of the stack) and the crystalline silicon cell (bottom of the stack) in the stacked state.

[0076] (3) Post-lamination testing: Testing the performance of the perovskite cell (top of the stack) and the crystalline silicon cell (bottom of the stack) in the 4T stacked cell obtained after lamination.

[0077] The test results are shown in Tables 4 to 6. After the crystalline silicon cell with a neodymium fluoride passivation layer is combined with the perovskite cell and laminated to form a 4-terminal stacked cell, the conversion efficiency is close to the efficiency before cutting. The top and bottom efficiencies after lamination are improved compared to before lamination.

[0078]

[0079]

[0080]

[0081] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A crystalline silicon solar cell, characterized in that: A passivation layer is arranged on the crystalline silicon solar cell sheet, and the passivation layer contains lanthanide rare earth fluoride.

2. The crystalline silicon solar cell according to claim 1, characterized in that: It comprises a first electrode, a back surface field layer, a polysilicon layer, a front surface field layer, the passivation layer and a second electrode which are stacked in sequence; the passivation layer is also arranged on the side surface of the crystalline silicon solar cell.

3. The crystalline silicon solar cell according to any one of claims 1 or 2, characterized in that: The crystalline silicon solar cell has at least one cutting surface, and the passivation layer is arranged on the cutting surface of the crystalline silicon solar cell.

4. The crystalline silicon solar cell according to claim 1, characterized in that: The lanthanide rare earth fluoride is neodymium fluoride.

5. The crystalline silicon solar cell according to claim 1, characterized in that: The thickness of the passivation layer is 0.001-0.01 μm.

6. The method for preparing a crystalline silicon solar cell according to any one of claims 1 to 5, characterized in that: The steps include: Passivation: The lanthanide rare earth fluoride is deposited on the surface of the polysilicon layer and / or the surface of the front surface field layer and / or the surface of the back surface field layer of the crystalline silicon solar cell to form the passivation layer.

7. The method for preparing a crystalline silicon solar cell according to claim 6, characterized in that: The steps include: Cutting: Cut the large crystalline silicon cell into several small crystalline silicon cells according to the preset area; Passivation: The lanthanide rare earth fluoride is deposited on the cut surface of the small crystalline silicon cell to form the passivation layer.

8. The method for preparing a crystalline silicon solar cell according to any one of claims 6 or 7, characterized in that: The specific method of the deposition is evaporation, and the conditions of the evaporation are: vacuum degree 1.0×10 -4 ~1.0×10 -3 Pa, temperature 1500~1900℃, time ≤10min.

9. The method for preparing a crystalline silicon solar cell according to any one of claims 6 or 7, characterized in that: After the deposition step, a vacuuming step is further included, wherein the vacuuming condition is: the vacuum degree reaches 10-90 kPa at a temperature of 100-150° C. and is maintained for more than 250 seconds.

10. A laminated battery, characterized in that: It comprises a crystalline silicon solar cell as described in any one of claims 1 to 5.

Images