Method for manufacturing a crystalline solar cell unit

Abstract

The present invention provides a method for manufacturing a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate. On the passivation film of the crystalline solar cell unit having a passivation film on one or both sides of the silicon substrate, one or more electrodes are formed in a size close to the opening width. The manufacturing method sequentially includes: (1) Step 1, when the passivation film is on the single side, the passivation film is a passivation film A having one or more openings; when the passivation film is on both sides, one or two of the passivation films are passivation film A having one or more openings, and a coating film composed of an electrode-forming paste composition is formed in the region covering the opening; (2) Step 2, firing the silicon substrate and the coating film; and (3) Step 3, at least retaining the fired products (8, 9) formed in a manner of filling the recesses of the opening, and removing a part or all of the fired products (7) formed in other manners.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate. Background Art

[0002] In recent years, as a crystalline solar cell unit with high conversion efficiency, a unit having a structure with insulating films (passivation films) on both sides of a silicon solar cell unit has been actively developed. Specifically, a PERC (Passivated emitter and rear cell) type unit using a p-type silicon substrate and having passivation films and electrodes formed on both sides, and a PERT (Passivated emitter and rear totally diffused cell) type unit using an n-type silicon substrate and having passivation films and electrodes formed on both sides are known.

[0003] In addition, a passivation contact type unit in which the passivation effect is improved by forming an oxide thin film and a silicon thin film between the passivation film and the silicon substrate in a PERC type or PERT type unit, a back contact type unit in which the front (front) electrodes of these PERC type, PERT type, and passivation contact type units are integrated on the back of the unit, etc. are also known.

[0004] Furthermore, the development of a bifacial solar cell unit has also been continuously progressing. The bifacial solar cell unit is a structure in which the back aluminum electrode in a PERC type unit is printed in a linear shape so that sunlight can also enter from the back, thereby improving the characteristics (Non-Patent Document 1, Fig. 4, Fig. 7, etc.).

[0005] The bifacial solar cell can increase the amount of incident light by reducing the area of the back aluminum electrode. However, in the past, it has been difficult to form fine lines by screen printing using an aluminum-containing paste composition (paste composition) for forming the back electrode. Generally, a fine line width of about 200 μm that can be formed by screen printing is regarded as the limit. That is, in the past, it has been difficult to form a linear back electrode composed of fine lines with a width less than 200 μm.

[0006] Prior Art Documents

[0007] Non-Patent Documents

[0008] Non-Patent Document 1: "Understanding the rear-side layout of p-dopede bifacial PERC solar cells with simulation driven experiment", 7th International Conference on Silicon Photovoltaics, SiliconPV 2017, Energy procedia 124(2017)225-234 Summary of the Invention

[0009] Technical Problem to be Solved by the Invention

[0010] When forming an electrode using a paste composition for electrode formation as described above, for example, in the case of a PERC-type cell, one or more openings are formed on the back surface passivation film formed on the silicon substrate by laser or the like, and a back surface aluminum electrode is formed by printing an aluminum-containing paste composition in the area covering the opening and firing it. In addition, the paste composition existing in a manner of filling the opening reacts with the silicon substrate during firing to form an electric field layer (aluminum-silicon (Al-Si) alloy layer, p + layer, etc.) to obtain a BSF (back surface field) effect.

[0011] Here, a bifacial light-receiving type in which light enters between linear back surface aluminum electrodes can be produced by printing the paste composition only in a partial area covering the opening. In addition, since the amount of light incident from the back surface depends on the area of the back surface aluminum electrode, it is necessary to form the back surface aluminum electrode in a size close to the opening width of the passivation film.

[0012] However, in the method of screen-printing the paste composition, a back surface aluminum electrode having a width several times that of the opening width is formed, so that the light incident from the back surface cannot be effectively utilized.

[0013] Therefore, the present invention has been completed to improve the problems in the above-mentioned prior art, and an object thereof is to provide a manufacturing method for a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate. In the case where the passivation film is provided on one side, one or more electrodes are formed on the passivation film in a size close to the opening width. In the case where the passivation film is provided on both sides, one or more electrodes are formed on one or two passivation films in a size close to the opening width. By forming the electrode in a size close to the opening width, it is possible to ensure an enlarged light-receiving area, more effectively utilize the incident light, and improve the power generation characteristics.

[0014] Technical Means for Solving the Technical Problem

[0015] In order to achieve the above object, the inventors of the present application conducted intensive research repeatedly. As a result, it was found that the above object can be achieved according to a manufacturing method of a crystalline solar cell unit having a specific process, and thus the present invention was completed.

[0016] That is, the present invention relates to a manufacturing method of a crystalline solar cell unit described below.

[0017] 1. A manufacturing method of a crystalline solar cell unit, which is a manufacturing method of a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate, characterized by sequentially comprising:

[0018] (1) Step 1, when the passivation film is on the one side, the passivation film is a passivation film A having one or two or more openings; when the passivation film is on both sides, one or two of the passivation films are passivation films A having one or two or more openings, and a coating film composed of a paste composition for forming an electrode is formed in a region covering the openings of the passivation film A;

[0019] (2) Step 2, firing the silicon substrate and the coating film; and

[0020] (3) Step 3, at least retaining the fired product formed in a manner of filling the recesses of the openings, and removing a part or all of the fired product formed in other manners.

[0021] 2. The manufacturing method of a crystalline solar cell unit according to item 1 above, wherein the openings are linear with a width of 20 to 100 μm each.

[0022] 3. The manufacturing method of a crystalline solar cell unit according to item 1 or item 2 above, wherein the paste composition for forming an electrode is an aluminum-containing paste composition, and contains 0.1 to 15 parts by mass of glass powder with respect to 100 parts by mass of aluminum powder.

[0023] 4. The manufacturing method of a crystalline solar cell unit according to item 3 above, wherein the aluminum-containing paste composition contains at least one selected from the group consisting of the following components: (1) glass powder containing at least one metal oxide selected from the group consisting of bismuth oxide, lead oxide, zinc oxide, silicon oxide, and magnesium oxide; (2) metal oxide; and (3) metal hydroxide.

[0024] Advantages of the Invention

[0025] According to the manufacturing method of the crystalline solar cell of the present invention, since the manufacturing method has the following steps, one or more electrodes can be formed in a size close to the opening width. The steps are as follows: for the fired product of the coating film of the paste composition for electrode formation applied to the region of the opening of the passivation film A having one or more openings in the covering passivation film, at least the fired product formed in such a way as to fill the recess of the opening is retained, and a part or all of the fired product formed in other ways is removed. By forming the electrode in a size close to the opening width, the light-receiving area can be ensured to be enlarged, the incident light can be utilized more effectively, and the power generation characteristics can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 (a) of FIG. is a top view observation image of the back aluminum electrode of the solar cell unit sample fabricated in Comparative Example 2 based on a laser microscope, and (b) is a top view observation image of the back aluminum electrode of the solar cell unit sample fabricated in Example 1 based on a laser microscope.

[0027] Figure 2 (a) of FIG. is a cross-sectional observation image of the back aluminum electrode of the solar cell unit sample fabricated in Comparative Example 2 based on SEM (scanning electron microscope), and (b) is a cross-sectional observation image of the back aluminum electrode of the solar cell unit sample fabricated in Example 1 based on SEM.

[0028] Figure 3 FIG. schematically shows a silicon substrate 1 having two openings 6 on the back passivation film 5.

[0029] Figure 4 FIG. is a schematic cross-section after applying an aluminum-containing paste composition to the region covering the two openings 6 of the back passivation film 5 and drying and firing. Here, reference numeral 7 is the fired product of the aluminum-containing paste composition, reference numeral 8 is the Al-Si alloy layer, and reference numeral 9 is the p + layer.

[0030] Figure 5 is a schematic view after removing the Figure 4 fired product 7 of the aluminum-containing paste composition existing outside the opening (the part not in the form of filling the recess) in FIG.. In this schematic view, the Al-Si layer 8 is used as the back aluminum electrode. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, the manufacturing method of the crystalline solar cell unit of the present invention (also referred to as "the manufacturing method of the present invention") will be described in detail.

[0032] The manufacturing method of the present invention is a manufacturing method of a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate, and successively includes:

[0033] (1) Step 1: When there is a passivation film on one side, the passivation film is a passivation film A having one or more than two openings; when there are passivation films on both sides, one or two of the passivation films are passivation film A having one or more than two openings, and a coating film composed of a paste composition for forming an electrode is formed in a region covering the opening of the passivation film A.

[0034] (2) Step 2: Firing treatment is performed on the silicon substrate and the coating film; and

[0035] (3) Step 3: At least the fired product formed in a manner of filling the recess for closing the opening is retained, and a part or all of the fired product formed in other manners is removed.

[0036] According to the manufacturing method of the present invention described above, since the manufacturing method has the following steps, one or more electrodes can be formed in a size close to the opening width. The steps are as follows: for the fired product of the coating film of the paste composition for forming an electrode coated in the region covering the opening of the passivation film A having one or more than two openings in the passivation film, by at least retaining the fired product formed in a manner of filling the recess for closing the opening, and removing a part or all of the fired product formed in other manners. By forming the electrode in a size close to the opening width, the light-receiving area can be ensured to be enlarged, the incident light can be utilized more effectively, and the power generation characteristics can be improved.

[0037] Hereinafter, each step of the manufacturing method of the present invention will be described with reference to the drawings.

[0038] In addition, the manufacturing method of the crystalline solar cell unit of the present invention is a manufacturing method of a crystalline solar cell unit having a passivation film on one side or both sides of a silicon substrate. When there is a passivation film on one side, the passivation film is a passivation film A having one or more than two openings; when there are passivation films on both sides, one or two of the passivation films are passivation film A having one or more than two openings. Here, the passivation film other than the passivation film A refers to a passivation film without an opening.

[0039] When there is a passivation film A on one side of the silicon substrate, for example, the passivation film A can be a back surface passivation film, and a back electrode (for example, a back aluminum electrode) is formed in a size close to the opening width. In addition, when there are passivation films A on both sides of the silicon substrate, for example, a back electrode (for example, a back aluminum electrode) is formed in a size close to the opening width on the back surface passivation film, and at the same time, a front electrode (for example, a silver electrode, a copper electrode, or an aluminum electrode) is formed in a size close to the opening width on the front surface (front side, the same hereinafter) passivation film.

[0040] Thus, the forms applicable to the manufacturing method of the present invention vary depending on the type of electrode or the surface on which the electrode is provided. However, even when an electrode is provided on either the front surface and / or the back surface of a silicon substrate, a coating film composed of an electrode-forming paste composition (such as an aluminum paste composition, a silver paste composition, a copper paste composition, etc., depending on the type of electrode) can be formed in the region covering the opening of the passivation film A having one or more openings (process 1 described later). Further, by processing the fired product according to processes 2 and 3 described later, one or more electrodes can be formed in a size close to the opening width. In addition, when the passivation film A is provided on both sides (front surface and back surface) of the silicon substrate, process 1 (as well as processes 2 and 3 described later) for the front surface passivation film A and process 1 (as well as processes 2 and 3 described later) for the back surface passivation film A can be carried out simultaneously on both sides, or can be carried out separately for the front surface and the back surface instead of simultaneously. Hereinafter, the present invention will be described while particularly exemplarily showing a scheme of forming a back surface aluminum electrode in a size close to the opening width at the opening of the back surface passivation film A in the surface passivation film and the back surface passivation film in a PERC type cell (also referred to as "this scheme").

[0041] Step 1 (Coating a paste composition on the region covering the opening)

[0042] In process 1, a coating film composed of an electrode-forming paste composition is formed in the region covering the opening of the passivation film A.

[0043] As the silicon substrate, for example, a p-type silicon substrate, an n-type silicon substrate, and a silicon substrate formed by combining them can be used. Hereinafter, while referring to a Figures 3 to 5 this scheme will be described.

[0044] The thickness of the silicon substrate 1 (p-type silicon substrate) is not limited, but a silicon substrate with a thickness of 180 to 250 μm is preferably used.

[0045] A configuration can be used in which an n-type silicon layer 3 with a thickness of, for example, 0.3 to 0.6 μm, a surface passivation film 2 composed of a silicon nitride film as an antireflection film, and a silver (Ag) electrode 4 as a gate electrode are provided on one surface (front surface) of the silicon substrate 1.

[0046] A configuration can be used in which a back surface passivation film 5 composed of, for example, a laminated film of an aluminum oxide film and a silicon nitride film is provided on the side opposite to the surface on which the silver electrode 4 is provided (back surface).

[0047] One or more openings 6 are provided in the back passivation film 5. That is, in this solution, the back passivation film 5 is passivation film A. The opening 6 is an opening for contacting the silicon substrate 1 and can be formed by laser irradiation, etching, etc. The shape of the opening 6 is not limited, and linear, curved, dotted, or dot-like shapes can be appropriately adopted. In addition, when forming a plurality of openings 6, their arrangement is not limited, and a regular arrangement or a random arrangement can be adopted.

[0048] In the present invention, it is preferable that each opening 6 is linear with a width of 20 to 100 μm, starting from the point of the control electrode pattern, and preferably, the openings 6 are regularly formed in the lateral and longitudinal directions in the plan view of the silicon substrate 1.

[0049] The paste composition only needs to be a paste composition for forming an electrode. In this solution, it is an aluminum-containing paste composition for forming a back aluminum electrode, specifically, a paste in which aluminum powder is dispersed in an organic solvent.

[0050] The composition of the aluminum powder is not particularly limited. Pure aluminum with a purity of 99 wt% or more can be used, or aluminum alloy powder can be appropriately used.

[0051] The shape of the aluminum powder includes spherical, ellipsoidal, etc., but is not particularly limited. Among them, spherical aluminum powder has good printability and good reactivity with silicon, so it is preferred. Regarding the size of the aluminum powder, from the perspectives of printability, reactivity, etc., it is preferably 1 μm or more and 20 μm or less in average particle diameter. More preferably, it is 1 μm or more and 6 μm or less.

[0052] In the paste composition, preferably 0.1 to 15 parts by weight of glass powder is contained relative to 100 parts by weight of the aluminum powder.

[0053] The composition of the glass powder is not particularly limited. For example, glass powder containing one or more components selected from the group consisting of B2O3, Bi2O3, ZnO, SiO2, Al2O3, BaO, CaO, SrO, V2O5, Sb2O3, WO3, P2O5, and TeO2 can be used. Among them, when using glass powder containing a B2O3 component (bismuth-based glass powder), the reactivity between silicon and aluminum is improved, so it is preferred.

[0054] In the present invention, since a part of the fired product of the paste composition will be removed in the subsequent step 3, in order to improve the removability, it is preferred that the paste composition contains glass powder, oxides, hydroxides, etc. that inhibit sintering.

[0055] The above-mentioned sintering-inhibiting glass powder may be a glass powder containing any one of metal oxides such as bismuth oxide, lead oxide, zinc oxide, silicon oxide, and aluminum oxide in an amount of 60% by weight or more. Examples of the above-mentioned sintering-inhibiting oxides include silicon oxide, aluminum oxide, calcium oxide, bismuth oxide, lead oxide, zinc oxide, germanium oxide, etc. Examples of the above-mentioned sintering-inhibiting hydroxides include aluminum hydroxide, zinc hydroxide, etc.

[0056] In the paste composition, usually in addition to containing aluminum powder, an organic solvent, a resin, a glass powder, etc. may also be contained. Its composition is not limited, and it can be set as follows: in 100% by mass of the paste composition, the aluminum powder is 60% by weight or more and 90% by weight or less, the organic solvent is 2% by weight or more and 20% by weight or less, and the remainder is 2% by weight or more and 20% by weight or less.

[0057] As the organic solvent, there is no limitation, and for example, diethylene glycol monobutyl ether, terpineol, etc. can be used.

[0058] In Step 1, a coating film composed of the paste composition is formed in a region covering one or more openings of the passivation film A. As the coating method, there is no limitation, and for example, methods such as screen printing or dispensing can be used. At this time, the paste composition is coated in such a way as to fill (fill) the concave portion of the opening, and at the same time, it is coated on the region covering the passivation film A within a range of 1 μm or more and 1000 μm or less from the end of the opening. In addition, the coating film thickness of the paste composition (the coating film thickness on the passivation film A) is preferably 10 μm or more and 40 μm or less. After coating, it is dried at room temperature or by heating.

[0059] Step 2 (Firing treatment)

[0060] In Step 2, the silicon substrate and the coating film are subjected to a firing treatment.

[0061] The firing treatment can be carried out in an air atmosphere or a nitrogen atmosphere. The firing temperature is preferably 500 °C or more and 1000 °C or less, and particularly more preferably 650 °C or more and 850 °C or less. The firing time can be adjusted according to the firing temperature and can be set to 3 seconds or more and 300 seconds or less.

[0062] Through the firing treatment, in this solution, the aluminum contained in the paste composition in the concave portion of the opening comes into contact with the silicon substrate, and aluminum and silicon react at the contact portion to form an electric field layer (Al-Si alloy layer 8, p + layer 9), and a fired product 7 of the paste composition is formed outside the concave portion of the opening (refer to Figure 4 ). And, due to the presence of the above-mentioned p + layer 9, the recombination of electrons can be prevented, and the BSF effect of improving the collection efficiency of generated carriers can be obtained.

[0063] Step 3 (Treatment for removing a part of the fired product)

[0064] In Step 3, at least the fired product formed in such a manner as to fill the recess for filling the opening is retained, and a part or all of the fired product formed in any other manner is removed.

[0065] In Step 3, at least the fired product formed in such a manner as to fill the recess for filling the opening ( Figure 4 alloy layer 8 and p + layer 9) is retained, and a part or all of the fired product formed in any other manner (the fired product of the paste composition formed outside the opening: Figure 4 fired product 7) is removed.

[0066] When removing part or all of the fired product 7, acid etching, polishing, etc. can be used. In addition, when the paste composition contains glass powder, oxides, hydroxides, etc. that inhibit sintering, part or all of the fired product 7 can be naturally peeled off without polishing, etc. In this solution, in order to most effectively utilize the light incident from the back surface, it is only necessary to remove all of the fired product 7 formed outside the opening. However, since the light utilization rate can be improved compared with the prior art by removing at least part of the fired product 7, the removal ratio can be appropriately set.

[0067] In this solution, by performing the above Steps 1 to 3 (especially Step 3), a back surface aluminum electrode can be formed in a size substantially the same as or close to the opening width of the passivation film, and the light incident from the back surface can be utilized more effectively.

[0068] In addition, a metal plating such as silver, copper, nickel, etc. can be formed on the back surface aluminum electrode formed in this solution by using a known technique, thereby reducing the resistance value of the electrode while maintaining the electrode area.

[0069] In addition, the present invention is not limited to the above solution, and can be widely applied to various cells of PERC type, PERT type, passivated contact type, back contact type, etc. when forming one or more electrodes on the surface and / or back surface passivation film A of the silicon substrate in a size close to the opening width. Regarding the back surface aluminum electrode, as described above, regarding other types of electrodes, a known paste composition for electrode formation can be applied to the manufacturing method of the present invention to fabricate an electrode well-known in the art.

[0070] Examples

[0071] Examples and comparative examples are shown below to specifically illustrate the present invention. However, the present invention is not limited to the examples.

[0072] Example 1

[0073] To 100 parts by mass of aluminum powder, 3 parts by mass of bismuth-based glass powder and 29 parts by mass of an organic vehicle are added, and they are mixed using a well-known mixer to prepare a paste composition.

[0074] On the back surface of a solar cell unit having a 45-μm-wide linear film opening in the back surface passivation film (passivation film A) of a PERC type solar cell with a wafer size of 156 mm square, using a screen mask with an opening width of 60 μm, the paste composition is applied by screen printing to an area covering the opening width of the back surface passivation film, dried at 100 °C for 10 minutes, and fired at 700 °C or higher and 4 seconds or less. After firing, the fired product of the paste composition that is not in the form of filling the opening is removed by acid etching the solar cell unit to obtain a solar cell unit specimen.

[0075] Figure 1 (b) of shows a top view observation image of the back surface aluminum electrode of the solar cell unit specimen fabricated in Example 1 based on a laser microscope. In addition, Figure 2 (b) of shows a cross-sectional observation image of the back surface aluminum electrode of the solar cell unit specimen fabricated in Example 1 based on SEM.

[0076] Example 2

[0077] A solar cell unit specimen is obtained in the same manner as in Example 1, except that a screen mask with an opening width of 100 μm is used and the paste composition is applied by screen printing to an area covering the opening width of the back surface passivation film.

[0078] Example 3

[0079] A solar cell unit specimen is obtained in the same manner as in Example 1, except that a screen mask with an opening width of 150 μm is used and the paste composition is applied by screen printing to an area covering the opening width of the back surface passivation film.

[0080] Comparative Example 1

[0081] To 100 parts by mass of aluminum powder, 3 parts by mass of bismuth-based glass powder and 29 parts by mass of an organic vehicle are added, and they are mixed using a well-known mixer to prepare a paste composition.

[0082] On the back surface of a solar cell unit having a 45-μm-wide linear film opening in a back surface passivation film (passivation film A) with a wafer size of 156 mm square, a paste composition was applied by screen printing to an area covering the opening width of the back surface passivation film using a screen mask with an opening width of 50 μm, dried at 100°C for 10 minutes, and fired at 700°C or higher and 4 seconds or less to obtain a solar cell unit specimen.

[0083] Comparative Example 2

[0084] A solar cell unit specimen was obtained in the same manner as in Comparative Example 1, except that a paste composition was applied by screen printing to an area covering the opening width of the back surface passivation film using a screen mask with an opening width of 60 μm.

[0085] Figure 1 The top view observation image of the back surface aluminum electrode of the solar cell unit specimen fabricated in Comparative Example 2 based on a laser microscope is shown in (a) of. In addition, Figure 2 The cross-sectional observation image of the back surface aluminum electrode of the solar cell unit specimen fabricated in Comparative Example 2 based on SEM (scanning electron microscope) is shown in (a) of.

[0086] Comparative Example 3

[0087] A solar cell unit specimen was obtained in the same manner as in Comparative Example 1, except that a paste composition was applied by screen printing to an area covering the opening width of the back surface passivation film using a screen mask with an opening width of 100 μm.

[0088] Comparative Example 4

[0089] A solar cell unit specimen was obtained in the same manner as in Comparative Example 1, except that a paste composition was applied by screen printing to an area covering the opening width of the back surface passivation film using a screen mask with an opening width of 150 μm.

[0090] Test Example 1

[0091] The back surface aluminum electrode of the obtained solar cell unit specimen was observed using a laser microscope (manufactured by KEYENCE CORPORATION), and the line width was measured. In addition, under the light of a solar simulator (manufactured by WACOM ELECTRIC CO., LTD), the power generation characteristics Isc on the back surface side were measured.

[0092] The results of the measured electrode width and Isc characteristics are shown in Table 1.

[0093] [Table 1]

[0094]

[0095] Based on the results in Table 1, it can be clearly confirmed that the electrode width of the solar cell unit sample manufactured by the method of the present invention is reduced, and the power generation characteristic Isc on the back side is improved.

[0096] When applying the paste composition by screen printing, when using a screen printing plate with a width of 50 μm, breaks were observed in the printed coating film. Therefore, it is preferable to use a screen printing plate with a width of 60 μm or more. When forming an electrode by the conventional method, even when using a screen printing plate with a width of 60 μm, the formed electrode is still about 130 μm wide. Therefore, it is difficult to form an electrode with a width of less than 60 μm by the conventional method.

[0097] For the samples (Examples 1 to 3) of the process of the fired product of the paste composition including the form of removing the opening that is not the buried passivation film A, regardless of the line width of screen printing, the final electrode width is 60 μm or less. Therefore, a screen printing plate with a screen width of any width from 60 μm to several hundred μm can be used.

[0098] Explanation of reference numerals

[0099] 1: Silicon substrate; 2: Surface passivation film; 3: n-type silicon layer (n + emitter layer); 4: Silver electrode; 5: Back passivation film (passivation film A); 6: Laser opening; 7: Fired product of paste composition; 8: Al-Si alloy layer; 9: p + layer.

Claims

1. A method for manufacturing a crystalline solar cell unit, which is a method for manufacturing a crystalline solar cell unit having a passivation film on one or both sides of a silicon substrate, characterized in that, Successively comprising: (1) Step 1: When there is a passivation film on the single side, the passivation film is a passivation film A having one or more openings; when there are passivation films on both sides, one or two of the passivation films are passivation film A having one or more openings, and each of the openings is a linear shape with a width of 20 to 100 μm, and a coating film composed of a paste composition for forming an electrode is formed in a region covering the openings of the passivation film A; (2) Step 2: Firing the silicon substrate and the coating film; and (3) Step 3: Retaining the fired product formed in a manner of filling the recesses of the openings, and removing all the fired products formed in other manners, and Step 3 is directly carried out after completing Step 2.

2. The manufacturing method of the crystalline solar cell unit according to claim 1, wherein, The paste composition for forming an electrode is an aluminum-containing paste composition, and contains 0.1 to 15 parts by mass of glass powder with respect to 100 parts by mass of aluminum powder.

3. The manufacturing method of the crystalline solar cell unit according to claim 2, wherein, The aluminum-containing paste composition contains at least one selected from the group consisting of the following components: (1) glass powder containing at least one metal oxide selected from the group consisting of bismuth oxide, lead oxide, zinc oxide, silicon oxide and magnesium oxide; (2) metal oxide; and (3) metal hydroxide.

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