TCO film layer structure of HJT cell, preparation method of TCO film layer structure and solar cell module

Abstract

The invention provides a TCO film layer structure of an HJT cell, a preparation method of the TCO film layer structure and a solar cell module, and relates to the technical field of solar cells. The front TCO thin film of the TCO film layer structure sequentially comprises a VTTO film layer, an FTO conductive film layer, an AZO conductive film layer and an ITO conductive film layer from inside to outside; the back TCO thin film sequentially comprises a back first VTTO film layer, an IWO conductive film layer and a back second VTTO film layer from inside to outside. Through the arrangement of the TCO film layer structure, the stability, the optical performance and the conductivity of the HJT battery can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a TCO film layer structure of an HJT cell, a preparation method thereof and a solar cell module. BACKGROUND

[0002] The HJT cell (amorphous silicon thin film heterojunction cell) is a photoelectric converter developed based on the photovoltaic effect. At present, the solar cells on the international photovoltaic market mainly include crystalline silicon (including single crystal silicon and polycrystalline silicon), amorphous / silicon heterojunction (HIT), amorphous silicon thin film, etc. Among them, the commercialized crystalline silicon solar cell still occupies the mainstream, and its photoelectric conversion efficiency has exceeded 26%, but it is difficult to further improve the conversion efficiency or reduce the cost due to the limitation of material purity and preparation process. Although the amorphous silicon solar cell can be produced in large area and has low cost, its conversion efficiency is still relatively low and its stability is poor. The TCO film layer preparation process of the existing HJT cell (the existing Mayvar-PVD ITO coating machine) is a process setting of coating all the film layers on the front surface first and then coating the film layers on the back surface. It only meets the preparation of single film layer and cannot meet the simultaneous preparation of multiple film layers. Therefore, more cavities are required in the preparation process, and the process needs to be switched and the target material needs to be replaced constantly. The process is too complex, which seriously affects the stability and efficiency of the cell sheet and other performances. Especially when multiple film layers are prepared on the front film, the interference of the front film process on the back film process cannot be guaranteed, and the stability and extensibility of the prepared cell sheet are greatly affected.

[0003] Therefore, the present application is proposed. SUMMARY

[0004] Note: The Chinese interpretation of the English abbreviations in this application is as follows: HJT: heterojunction cell; TCO: transparent conductive oxide film; FTO: fluorine-doped tin oxide; AZO: aluminum-doped zinc oxide; ITO: indium-doped tin oxide (90% indium, 10% tin); IWO: tungsten-indium target; VTTO: indium-doped tin oxide (99% indium, 1% tin); PVD: physical vapor deposition; CVD: chemical vapor deposition; PECVD: plasma-enhanced chemical vapor deposition.

[0005] The first object of the present application is to provide a TCO film layer structure of an HJT cell, which can effectively improve the stability, optical performance and conductive performance of the HJT cell.

[0006] The second object of the present application is to provide a preparation method of a TCO film layer structure of an HJT cell.

[0007] In order to achieve the above-mentioned object of the present application, the following technical solutions are adopted: In one aspect, the present application provides a TCO film layer structure of an HJT cell.

[0008] Figure 1 The present application is an overall structure of an HJT cell.

[0009] By Figure 1 It can be seen that the overall structure of the HJT cell of the present application comprises: N-type monocrystalline silicon; i-type intrinsic amorphous silicon film, P-type amorphous silicon film and front TCO film grown in sequence on the front surface of the N-type monocrystalline silicon; i-type intrinsic amorphous silicon film, N-type amorphous silicon film and back TCO film grown in sequence on the back surface of the N-type monocrystalline silicon; and metal electrodes arranged on the front TCO film and the back TCO film. Among them: The front TCO film comprises, in sequence from the inside to the outside: VTTO film layer, FTO conductive film layer, AZO conductive film layer and ITO conductive film layer, and the metal electrodes are arranged on the ITO conductive film layer. The back TCO film comprises, in sequence from the inside to the outside: back first VTTO film layer, IWO conductive film layer and back second VTTO film layer, and the metal electrodes are arranged on the back second VTTO film layer.

[0010] It should be noted that the front and back TCO film layers of the existing HJT cell are usually obtained by sputtering of a VTTO target material only, but the TCO film layer of the single VTTO target material is prone to poisoning and nodulation after use to a certain power, which affects the cell efficiency; at the same time, in order to ensure the performance of the cell, the VTTO layer for preparing the front and back TCO films needs to be sputtered to a thickness of 110-120 nm, and the VTTO target material is relatively expensive, which is not good in economy.

[0011] Therefore, the present application provides a novel TCO film layer structure of an HJT cell, wherein the front TCO film of the TCO film layer structure comprises, in sequence from the inside to the outside: VTTO film layer, FTO conductive film layer, AZO conductive film layer and ITO conductive film layer. The VTTO film layer in the front TCO film is prepared by an ultrathin film layer process. (I) The advantages of the front TCO film layer structure of the present application over the existing front TCO film layer containing only VTTO are as follows: 1. The VTTO film layer in the front TCO film of the present application is prepared by an ultrathin film layer process, and the raw material of VTTO is indium-doped tin oxide (99% indium and 1% tin). Since indium material is relatively expensive, the existing VTTO film layer is about 110 nm, and the ultrathin VTTO film layer is only about 20-30 nm, which achieves the advantage of cost reduction from the material itself.

[0012] And the thinned VTTO film as the inner layer has better conductivity and optical performance, can better contact the microcrystalline film layer, and improve the current.

[0013] 2. To offset the influence of the ultra-thin VTTO film on the performance of the battery, the application adopts the scheme of combining FTO and AZO conductive films with the ITO film. The FTO and AZO conductive film layers reduce the cost due to the relatively cheap material. After the ITO film is combined with the FTO and AZO conductive films, the optical and conductive performance approaches that of the VTTO film layer, and the optical and conductive performance of the front TCO film layer is not reduced. At the same time, the combination of the FTO and AZO conductive film layers can increase the transmittance of the front surface, so that more carriers enter the PN junction, and the performance of the battery is improved. The ITO film layer as the outermost layer can better match the CU seed layer, improve the optical performance of the battery, and has better transmittance. Therefore, the arrangement of the front TCO film of the application not only realizes better matching and contact with the microcrystalline film layer and the CU seed layer, but also improves the transmittance of the front surface of the HJT battery, and does not reduce the optical and conductive performance of the VTTO film layer.

[0014] The back TCO film of the TCO film layer structure of the application comprises, from inside to outside, a back first VTTO film layer, an IWO conductive film layer, and a back second VTTO film layer. That is, the back TCO film of the application adopts a sandwich structure of VTTO / IWO / VTTO.

[0015] (2) The advantages of the back TCO film layer structure of the application relative to the existing back TCO film layer containing only VTTO are: 1. The VTTO film layer in the back TCO film of the application is prepared by an ultra-thin film layer process. The raw material of VTTO is indium-doped tin oxide (99% indium and 1% tin). Since indium material is relatively expensive, the existing VTTO film layer is about 110 nm, and the ultra-thin VTTO film layer is only about 20-30 nm, which achieves the advantage of reducing the cost from the material itself.

[0016] 2. The application introduces an IWO conductive film layer with ultra-high mobility in the back layer, which can effectively improve the performance of the HJT battery. However, the ultra-high mobility of the IWO film layer can also increase the sensitivity of the back film layer to the microcrystalline and the back CU grid line (the back film layer is the grid line contact surface), and affect the performance. Since the VTTO film layer has better matching with the I layer and is not affected by any film layer impurities, the application adopts a sandwich structure of VTTO / IWO / VTTO on the back, which can effectively reduce the influence of other film layers on the performance of the IWO film.

[0017] In addition, the outermost layer still has a low long-wavelength light transmission coefficient by using VTTO (the IWO still uses a thinning process), and the tension coefficient and stability between the VTTO film layer and the CU are not affected.

[0018] (Three), the front surface of the TCO film layer structure of the application introduces an ITO film layer, and the back surface introduces an IWO film layer. The IWO itself has a very high mobility, the ITO target material has a relatively high conductivity, and the resistivity is also larger than that of VTTO; therefore, the combination of ITO and IWO can achieve a synergistic effect, effectively reducing the resistance Rs, improving the FF, and improving the electrical performance of the HJT.

[0019] In summary, by arranging the above-mentioned TCO film layer structure, the stability, optical performance and conductivity of the HJT cell can be effectively improved. In particular, the front surface TCO film layer of the application adopts the scheme of combining FTO, AZO conductive film and ITO film, realizes the complementation of materials, and the optical and electrical performance after combination is close to that of the VTTO film layer, which can effectively improve the short-circuit current Isc and the fill factor FF of the HJT; at the same time, the use of FTO and AZO materials also reduces the cost of materials.

[0020] In a preferred embodiment of the application, the ITO conductive film layer in the front surface TCO thin film is prepared by a film reduction process; and, the IWO conductive film layer in the back surface TCO thin film is prepared by a film reduction process.

[0021] As a preferred embodiment, the ITO conductive film layer and the IWO conductive film are prepared by a film reduction process, although Voc and Isc will be reduced, the complementation through the composite layer will significantly improve other electrical properties of the battery, such as FF.

[0022] In a preferred embodiment of the application, the thickness of the front surface TCO thin film is 110 nm, wherein: the VTTO film layer is 20 nm, the FTO conductive film layer is 30 nm, the AZO conductive film layer is 30 nm, and the ITO conductive film layer is 30 nm. The thickness of the back surface TCO thin film is 120 nm, wherein: the first back surface VTTO film layer is 20 nm, the IWO conductive film layer is 80 nm, and the second back surface VTTO film layer is 20 nm.

[0023] According to another aspect of the application, a preparation method of the TCO film layer structure of the above-mentioned HJT cell, the TCO film layer structure uses a mixed gas phase deposition method to prepare a TCO mixed film layer, and a transition cavity is arranged between each deposition cavity.

[0024] The application provides a preparation method of a TCO film layer structure of an HJT cell.

[0025] In a preferred embodiment of the application, the preparation method comprises: (A) providing an HJT cell intermediate A without a deposited TCO film layer structure; The HJT cell intermediate A comprises the following structure: N-type monocrystalline silicon as a base substrate; i-type intrinsic amorphous silicon film and P-type amorphous silicon film grown on the front surface of the N-type monocrystalline silicon in sequence; i-type intrinsic amorphous silicon film and N-type amorphous silicon film grown on the back surface of the N-type monocrystalline silicon in sequence; (B1) depositing a VTTO layer on the front surface and the back surface of the HJT cell intermediate A by using a physical vapor deposition method in a first physical vapor deposition cavity to obtain an HJT cell intermediate B; It should be noted that the front surface and the back surface of the application are first deposited with the VTTO layer because the main component of the VTTO target material is indium, and the conductive performance and optical performance are good, and the first layer of the front surface and the back surface is the VTTO film layer to better match the existing microcrystalline film layer, so as to obtain higher current Isc and fill factor FF, thereby improving the efficiency; (B2) depositing and preparing an FTO conductive film layer and an AZO conductive film layer on the front surface VTTO layer of the HJT cell intermediate B in sequence by using a chemical vapor deposition method in a first chemical vapor deposition cavity to obtain an HJT cell intermediate C; It should be noted that the FTO and AZO conductive film layers are deposited and prepared on the front surface VTTO layer by using the chemical vapor deposition method, and the coverage, uniformity and crystallinity of the prepared FTO and AZO conductive film layers are better than those of the physical vapor deposition. In addition, a transition cavity is arranged between the FTO conductive film layer and the AZO conductive film layer deposition cavities, which can effectively prevent the process gas in the process cavity from entering other cavities, causing mixed gas and preventing gas from jumping.

[0026] (B3) depositing an IWO conductive film layer on the back surface of the HJT cell intermediate C and depositing an ITO conductive film layer on the front surface of the HJT cell intermediate C by using a physical vapor deposition method in a second physical vapor deposition cavity; and then depositing a second VTTO film layer on the IWO conductive film layer; It should be noted that when the front film FTO and AZO film layer are prepared in step (B2), the film layer quality of the back film VTTO film layer tends to be stable after a period of deposition. Since the indium in the VTTO just after deposition has high activity, the metal oxide is also prone to inter-doping with IWO (having a super-high mobility coefficient), thereby affecting the matching quality of the VTTO film layer and the microcrystalline layer, and the IWO film layer is an ultra-thin film layer, which is more susceptible to influence. In order to minimize the influence of the long-wavelength light transmission coefficient of the IWO on the overall film layer and not affect the VTTO film layer, the back surface of the present application simultaneously prepares the IWO and the outer VTTO in the same cavity, so that the IWO and the ITO inner layer thin surface edge slightly penetrate atoms, thereby minimizing the influence of the high long-wavelength light transmission coefficient of the IWO on the battery performance.

[0027] In addition, since the AZO and FTO sandwich layer are also prepared at high temperature (just after sputtering) when mixed, they also have high activity, and FTO etching is easier, and high activity is more susceptible to affecting and being affected by other film layers. In order to avoid the influence of the sandwich layer on the front film VTTO film layer, the sandwich film layer and the front film VTTO film layer are plated in batches.

[0028] (C) A Cu seed layer is sputtered by a physical vapor deposition method to obtain a HJT battery with a TCO film layer structure.

[0029] According to one aspect of the present application, a solar cell module includes a plurality of HJT batteries connected in series or in parallel, and the HJT battery is the above-mentioned HJT battery.

[0030] The present application provides a solar cell module, which includes a plurality of the above-mentioned HJT batteries connected in series or in parallel.

[0031] Compared with the prior art, the present application has the following advantages: The present application provides a HJT battery TCO film layer structure, and the front TCO thin film of the TCO film layer structure comprises, from inside to outside, a VTTO film layer, an FTO conductive film layer, an AZO conductive film layer, and an ITO conductive film layer; and the back TCO thin film comprises, from inside to outside, a back first VTTO film layer, an IWO conductive film layer, and a back second VTTO film layer. The above-mentioned TCO film layer structure can effectively improve the stability, optical performance, and conductive performance of the HJT battery. In particular, the front TCO film layer of the present application adopts the scheme of combining FTO, AZO conductive film, and ITO film, realizes material complementation, and after combination, the optical performance and electrical performance are close to the VTTO film layer, which can effectively improve the short-circuit current Isc and the fill factor FF of the HJT. At the same time, the use of FTO and AZO materials also reduces the cost of materials.

[0032] The application provides a preparation method of a TCO film layer structure of an HJT cell.

[0033] The application provides a solar cell module. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0035] Figure 1 FIG. 1 is a schematic diagram of the overall structure of the HJT cell of the present application; Figure 2 FIG. 2 is a schematic diagram of the preparation machine table setting of the HJT cell TCO film layer structure provided in Embodiment 1 of the present application; Figure 3 FIG. 3 is a schematic diagram of the preparation process flow chart of the HJT cell TCO film layer structure provided in Embodiment 1 of the present application; Figure 4 FIG. 4 is a schematic diagram of the HJT cell TCO film layer structure prepared by part of the cavity provided in Embodiment 1 of the present application; Figure 5 FIG. 5 is a schematic diagram of the TCO film table structure setting provided in Embodiment 2 of the present application. DETAILED DESCRIPTION

[0036] The technical solutions of the present application will be described below in conjunction with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort are within the scope of protection of the present application.

[0037] The technical solutions of the present application will be further described below in conjunction with the embodiments.

[0038] Embodiment 1 Figure 1The whole structure schematic diagram of the HJT cell of the present application.

[0039] Figure 2 The preparation machine setting diagram of the HJT cell TCO film layer structure provided in the present embodiment; Figure 3 The preparation process flow chart of the HJT cell TCO film layer structure provided in the present embodiment; Figure 4 The HJT cell TCO film layer structure prepared by the partial cavity provided in the present embodiment.

[0040] Referring to Figure 2 , Figure 3 , a preparation method of an HJT cell TCO film layer structure, the preparation method comprises: (1) providing an HJT cell intermediate A without a deposited TCO film layer structure; The HJT cell intermediate A comprises the following structure: N-type monocrystalline silicon as a base substrate; N-type monocrystalline silicon with i-type intrinsic amorphous silicon film and P-type amorphous silicon film grown in sequence on the front side; N-type monocrystalline silicon with i-type intrinsic amorphous silicon film and N-type amorphous silicon film grown in sequence on the back side; (2) referring to Figure 2 , 3 C1-C5 cavities, a VTTO layer is deposited on the front side and the back side of the HJT cell intermediate A by a physical vapor deposition method to obtain an HJT cell intermediate B, specifically: C1: vacuum pumping cavity, mainly for the purpose of entering the vacuum state from the atmosphere of the carrier; C2: heating cavity, removing water vapor on the carrier; C3: heating cavity, removing water vapor on the carrier; C4: physical vapor deposition, process cavity, depositing materials on the silicon wafer by physical means, depositing a VTTO layer on the front side and the back side respectively; The deposition parameters are: target material: VTTO target material, power 10kw, thickness 20nm, pressure 0.6pa, deposition time 45s; C5: transition cavity, preventing process gas from jumping between process cavities; Referring to Figure 4 , the cell film layer structure after deposition of the C4 cavity.

[0041] (3) referring to Figure 2 , 3C6, C7 cavity in the C8, C9 cavity in the C10~13 cavity in the The FTO, AZO conductive film layer deposition process is provided with a transition cavity to prevent process gas from jumping between process cavities. The deposition parameters are: power 11kw, O2 22sccm, H2 1000sccm.

[0042] The FTO conductive film thickness is 30nm, and the AZO conductive film thickness is 30nm.

[0043] C7: Transition cavity to prevent process gas from jumping between process cavities. (4) Referring to Figure 1 , 2 C8, C9 cavity in the C10~13 cavity in the The deposition parameters are: Positive: 3.5kw, O2 13sccm, Ar375sccm / Ar / H2 625sccm; Back: 4.2kw, 02 15sccm, Ar425sccm / Ar / H2 575sccm; C9: Transition cavity to prevent process gas from jumping between process cavities. Referring to Figure 4 It can be seen that the battery film layer structure after deposition in the C8 cavity.

[0044] (5) Referring to Figure 1 , 2 C10~13 cavity in the C10~13 cavity in the

[0045] C10: Sputtering Cu seed layer; The sputtering parameters are: positive and back 5kw, Ar1000sccm.

[0046] C11, C12: Cooling to reduce the temperature of the silicon wafer; C13: Empty cavity, which allows the carrier to enter the atmosphere from a vacuum state.

[0047] The thickness of the TCO film layer structure prepared in this embodiment is as follows: The thickness of the front TCO film is 110 nm, wherein: the VTTO film layer is 20 nm, the FTO conductive film layer is 30 nm, the AZO conductive film layer is 30 nm, and the ITO conductive film layer is 30 nm. The thickness of the back TCO film is 120 nm, wherein: the back first VTTO film layer is 20 nm, the IWO conductive film layer is 80 nm, and the back second VTTO film layer is 20 nm.

[0048] Example 2 Existing Mayvar-PVD ITO coating machine Figure 5 The TCO coating machine structure provided for this embodiment is shown in the figure; A preparation method of a TCO film layer structure of an HJT cell, the preparation method comprising: (1) the same as in Example 1; (2) depositing a TCO film layer structure: A TCO film layer structure of an HJT cell is deposited in the C4 cavity of this embodiment by a physical vapor deposition method, and the TCO film layer structure is the same as in Example 1.

[0049] The difference between this embodiment and Example 1 is that the same TCO film layer structure as in Example 1 is prepared in a single sputtering cavity by a physical vapor deposition method.

[0050] Example 3 This embodiment is different from Example 1 in that: The C6 cavity of step (3) does not set a transition cavity between the deposition processes of the FTO and AZO conductive film layers, and uses a chemical vapor deposition method to continuously deposit the FTO and AZO conductive film layers.

[0051] The difference between this embodiment and Example 1 is that a transition cavity is not set between the deposition processes of the FTO and AZO conductive film layers.

[0052] Example 4 This embodiment is different from Example 1 in that: The C6 cavity of step (3) uses a physical vapor deposition method to prepare the FTO and AZO conductive film layers; and the rest is the same as in Example 1.

[0053] The difference between this embodiment and Example 1 is that a physical vapor deposition method is used to prepare the FTO and AZO conductive film layers.

[0054] Example 5 This embodiment is the same as Example 1 except that no C5, C7, and C9 transition cavities are set in the preparation process of the TCO film layer structure.

[0055] Comparative Example 1 A HJT cell TCO film structure, the front and back surfaces of the TCO film are both VTTO film layers, and the thickness is 120 nm.

[0056] The difference between the present comparative example and example 1 is that the front and back TCO films of the present comparative example are only VTTO film layers.

[0057] Comparative example 2 A HJT cell TCO film structure, the front TCO film comprises, from inside to outside, a VTTO film layer and an ITO conductive film layer, and a metal electrode is arranged on the ITO conductive film layer; the back TCO film comprises, from inside to outside, a back first VTTO film layer, an IWO conductive film layer and a back second VTTO film layer, and a metal electrode is arranged on the back second VTTO film layer; The thickness of the front TCO film is 110 nm, wherein the VTTO film layer is 20 nm, the ITO conductive film layer is 30 nm. The thickness of the back TCO film is 120 nm, wherein the back first VTTO film layer is 20 nm, the IWO conductive film layer is 80 nm, and the back second VTTO film layer is 20 nm.

[0058] The difference between the present comparative example and example 1 is that the front TCO film does not contain an FTO conductive film layer and an AZO conductive film layer.

[0059] Comparative example 3 A HJT cell TCO film structure, the front TCO film comprises, from inside to outside, a VTTO film layer, an FTO conductive film layer and an AZO conductive film layer, and a metal electrode is arranged on the AZO conductive film layer; the back TCO film comprises, from inside to outside, a back first VTTO film layer, an IWO conductive film layer and a back second VTTO film layer, and a metal electrode is arranged on the back second VTTO film layer; The thickness of the front TCO film is 110 nm, wherein the VTTO film layer is 20 nm, the FTO conductive film layer is 30 nm, and the AZO conductive film layer is 30 nm. The thickness of the back TCO film is 120 nm, wherein the back first VTTO film layer is 20 nm, the IWO conductive film layer is 80 nm, and the back second VTTO film layer is 20 nm.

[0060] The difference between the present comparative example and example 1 is that the front TCO film does not contain an ITO conductive film layer.

[0061] Comparative example 4 A HJT cell TCO film structure, the front surface TCO film comprises from inside to outside: an FTO conductive film layer, an AZO conductive film layer and an ITO conductive film layer, and a metal electrode is arranged on the ITO conductive film layer; The back surface TCO film comprises from inside to outside: an IWO conductive film layer and a VTTO film layer, and a metal electrode is arranged on the VTTO film layer; The thickness of the front surface TCO film is 110nm, wherein the FTO conductive film layer is 30nm, the AZO conductive film layer is 30nm and the ITO conductive film layer is 30nm. The thickness of the back surface TCO film is 120nm, wherein the IWO conductive film layer is 80nm and the VTTO film layer is 20nm.

[0062] The main difference between the comparative example and example 1 is that the inner layer of the front and back surface TCO film is not a VTTO film layer.

[0063] Comparative example 5 A HJT cell TCO film structure, the front surface TCO film comprises from inside to outside: a VTTO film layer, an FTO conductive film layer, an AZO conductive film layer and an ITO conductive film layer, and a metal electrode is arranged on the ITO conductive film layer; The back surface TCO film comprises from inside to outside: a VTTO film layer, and a metal electrode is arranged on the VTTO film layer; The thickness of the front surface TCO film is 110nm, wherein the VTTO film layer is 20nm, the FTO conductive film layer is 30nm, the AZO conductive film layer is 30nm and the ITO conductive film layer is 30nm. The thickness of the back surface TCO film is 120nm, wherein the VTTO film layer is 120nm.

[0064] The main difference between the comparative example and example 1 is that the back surface TCO film does not introduce an IWO conductive film layer.

[0065] Experimental example 1 In order to show that the setting of the TCO film layer structure of the present application can effectively improve the stability, optical performance and conductive performance of the HJT cell, the HJT cells prepared in examples 1-5 and comparative examples 1-5 are subjected to performance detection.

[0066] The specific detection results are shown in the following table:

[0067] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A TCO film layer structure of an HJT cell, characterized in that, The TCO film layer structure comprises: a front TCO film and a back TCO film; The front TCO film comprises, from inside to outside: a VTTO film layer, an FTO conductive film layer, an AZO conductive film layer and an ITO conductive film layer, and a metal electrode is arranged on the ITO conductive film layer; The back TCO film comprises, from inside to outside: a back first VTTO film layer, an IWO conductive film layer and a back second VTTO film layer, and a metal electrode is arranged on the back second VTTO film layer; The HJT cell is single-sided grid line, and the grid line is arranged on the back.

2. The TCO film layer structure of the HJT cell according to claim 1, characterized in that, The VTTO film layer in the front TCO film is prepared by an ultrathin film layer process; And the back first VTTO film layer and the back second VTTO film layer in the back TCO film are prepared by an ultrathin film layer process. 3.The TCO film layer structure of the HJT cell of claim 1, wherein, The ITO conductive film layer in the front TCO film is prepared by a film reduction process; And the IWO conductive film layer in the back TCO film is prepared by a film reduction process. 4.The TCO film layer structure of the HJT cell of claim 1, wherein, The thickness of the front TCO film is 110nm, wherein the VTTO film layer is 20nm, the FTO conductive film layer is 30nm, the AZO conductive film layer is 30nm and the ITO conductive film layer is 30nm; The thickness of the back TCO film is 120nm, wherein the back first VTTO film layer is 20nm, the IWO conductive film layer is 80nm and the back second VTTO film layer is 20nm. 5.The TCO film layer structure of the HJT cell of claim 1, wherein, The metal electrode is a copper electrode.

6. A method for preparing a TCO film layer structure of the HJT cell according to any one of claims 1-5, characterized in that, The TCO film layer structure is prepared by a hybrid vapor deposition method, and a transition cavity is arranged between each deposition cavity.

7. The method of claim 6, wherein the method further comprises depositing a layer of a buffer layer on the layer of the TCO layer. The preparation method comprises: (A) providing an HJT cell intermediate A without a deposited TCO film layer structure; The HJT cell intermediate A comprises the following structure: N-type monocrystalline silicon as a base substrate; An i-type intrinsic amorphous silicon film and a P-type amorphous silicon film are grown on the front of the N-type monocrystalline silicon; An i-type intrinsic amorphous silicon film and an N-type amorphous silicon film are grown on the back of the N-type monocrystalline silicon; (B) depositing a TCO film on the front and back of the HJT cell intermediate A by a hybrid vapor deposition method; The front TCO film comprises, from inside to outside: a VTTO film layer, an FTO conductive film layer, an AZO conductive film layer and an ITO conductive film layer, and a metal electrode is arranged on the ITO conductive film layer; The back TCO film comprises, from inside to outside: a back first VTTO film layer, an IWO conductive film layer and a back second VTTO film layer, and a metal electrode is arranged on the back second VTTO film layer; (C) sputtering a Cu seed layer by a physical vapor deposition method to obtain an HJT cell with a TCO film layer structure.

8. The method of claim 7, wherein the method further comprises depositing a TCO layer on the substrate. The step (B) comprises: (B1) depositing a VTTO layer on the front and back of the HJT cell intermediate A by a physical vapor deposition method in a first physical vapor deposition cavity to obtain an HJT cell intermediate B; (B2) depositing and preparing an FTO conductive film layer and an AZO conductive film layer on the front VTTO layer of the HJT cell intermediate B by a chemical vapor deposition method in a first chemical vapor deposition cavity to obtain an HJT cell intermediate C; (B3) in the second physical vapor deposition cavity, using a physical vapor deposition method to deposit an IWO conductive film layer on the back surface of the HJT cell intermediate C, and deposit an ITO conductive film layer on the front surface of the HJT cell intermediate C; then deposit a back surface second VTTO film layer on the IWO conductive film layer; The steps (B1), (B2) and (B3) are provided with a transition cavity between the deposition cavities.

9. The method of claim 8, wherein the method further comprises depositing a TCO layer on the substrate. The steps (B2) are provided with a transition cavity between the FTO conductive film layer and the AZO conductive film layer deposition cavities.

10. A solar cell module characterized by comprising: The HJT cell has the TCO film layer structure of any one of claims 1-5.

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