JP5179677B1 - Method for manufacturing solar battery cell - Google Patents

Abstract

Provided is a method for efficiently producing a solar battery cell having excellent light conversion efficiency.
(A) applying a conductive paste containing conductive metal particles on a silicon substrate to form electrode patterns on the light receiving surface and the back surface of the silicon substrate; and (b) step (a). A step of firing the electrode pattern formed in step (c), and a step (c) irradiating the fired electrode pattern formed on the light receiving surface in step (b) with light from a flash lamp. The manufacturing method of the photovoltaic cell.
[Selection figure] None

Description

  The present invention relates to a method for manufacturing a solar battery cell, and a solar battery cell manufactured thereby.

  In general, a solar battery cell having a p-type base typically has a negative electrode on the light receiving surface (front surface, that is, the solar side) of the battery and a positive electrode on the back surface. It is known that radiation of the appropriate wavelength directed onto the pn junction of the semiconductor body functions as an external energy source and generates hole-electron pairs in the semiconductor body. Due to the potential difference present at the pn junction, the holes and electrons move across the pn junction in the opposite direction. The movement of holes and electrons in the opposite direction creates a current flow that allows power to be supplied to the external circuit.

  In the power generation performance of the solar battery cell, the light conversion efficiency (EFF (%)) is an important factor. Conventionally, various methods have been proposed in order to improve the power generation performance of solar cells by achieving excellent conversion efficiency. For example, a technology for producing a light-receiving surface electrode having sufficient conductivity by firing a conductive paste containing at least one metal selected from Ti, Bi, Zn, Y, In and Mo or a metal compound thereof. Has been proposed (see Patent Document 1). However, when firing the conductive paste, there are problems such as an increase in contact resistance due to shrinkage of the coating film and / or generation of cracks. The problems that occur during such firing greatly affect the performance of the solar battery cell and greatly reduce the conversion efficiency.

  Conventionally, there has been an example in which improvement of light conversion efficiency is attempted by using conditions that sufficiently melt the glass frit contained in the paste during firing. In this case, firing at a high temperature and a long time sufficient for melting is necessary, and there is a possibility that an adverse effect on the semiconductor body may occur.

JP-A-2005-243500

  At the present time, there is a need for a technique for providing a solar cell that can more effectively suppress adverse effects on the solar cell during firing and achieve higher light conversion efficiency. That is, an object of the present invention is to provide a method for efficiently producing a solar cell having excellent light conversion efficiency, and to provide a solar cell produced by the production method and having high power generation performance.

In order to solve the above problems, a method for producing a solar battery cell of the present invention is as follows.
(A) applying a conductive paste containing conductive metal particles on a silicon substrate and forming electrode patterns on the light-receiving surface and the back surface of the silicon substrate;
(B) firing the electrode pattern formed in the step (a);
(C) irradiating the baked electrode pattern formed on the light receiving surface in the step (b) with flash lamp light.

  By adopting the above-described configuration, it is possible to effectively manufacture a solar battery cell that effectively suppresses adverse effects on the solar battery cell during firing and exhibits excellent light conversion efficiency. Moreover, the photovoltaic cell obtained by the said method has the outstanding electric power generation performance.

It is a figure explaining the manufacturing method of the photovoltaic cell of the present invention, and (a)-(d) is a figure for explaining each process.

The manufacturing method of the solar battery cell of the present invention is as follows.
(A) applying a conductive paste containing conductive metal particles on a silicon substrate and forming electrode patterns on the light-receiving surface and the back surface of the silicon substrate;
(B) firing the electrode pattern formed in the step (a);
(C) irradiating the fired electrode pattern formed on the light receiving surface in the step (b) with light from a flash lamp. The method of the present invention may include other steps as required. Hereafter, each process of this invention is demonstrated in detail.

Step (a) Electrode Pattern Forming Step In the electrode pattern forming step, a conductive paste is applied on the silicon substrate, and electrode patterns are formed on the light receiving surface and the back surface of the silicon substrate.

(1) Silicon substrate The silicon substrate used in the present invention has a light receiving surface and a back surface opposite to the light receiving surface, and has a pn junction between the light receiving surface and the back surface. The silicon substrate may be either a single crystal silicon substrate or a polycrystalline silicon substrate. When a p-type silicon substrate is used, an n-type layer is formed on the light receiving surface side. The n-type layer can be formed, for example, by thermal diffusion of a donor dopant. Donor dopants that can be used include phosphorous oxychloride (POCl ₃ ) and the like.

  The silicon substrate used in the present invention may have an uneven light receiving surface for confining incident radiation in the silicon substrate. Alternatively, an antireflection layer (such as a silicon nitride film) may be provided on the light receiving surface of the silicon substrate to confine incident radiation in the silicon substrate.

(2) Conductive paste for forming electrode pattern on light receiving surface The conductive paste for forming a light receiving surface electrode pattern contains at least conductive metal particles. If necessary, the conductive paste for forming a light-receiving surface electrode pattern may contain glass frit, a lead-tellurium-containing composite oxide, an organic vehicle, and / or an additive known in the art.

(2-1) Conductive metal particles In one embodiment, metal particles such as iron, aluminum, nickel, copper, silver, gold, molybdenum, magnesium, tungsten, cobalt, and zinc are used as the conductive metal particles. it can. The conductive metal particles can include one or more of these metal particles.

In another embodiment, particles such as metals or alloys having a conductivity of 3.00 × 10 ⁷ S / m or more can be used as the conductive metal particles. By using conductive metal particles having higher conductivity, the light conversion efficiency of the solar battery cell can be improved.

  Specifically, aluminum, copper, silver or gold particles are preferably used as the conductive metal particles. It is particularly preferable to use silver particles as conductive metal particles. This is because oxidation is unlikely to occur in the firing step of step (b).

  There is no restriction | limiting in particular in the shape of the electroconductive metal particle used for this invention. Metal or alloy particles having various shapes such as flakes and spheres can be used as the conductive metal particles. In addition, the conductive metal particles used in the present invention may be composed of metal or alloy particles having the same shape, or may be composed of metal or alloy particles having different shapes. In consideration of a conductive paste application method (for example, application by screen printing) described later, the shape of the conductive metal particles used in the present invention can be appropriately selected.

A weight average particle diameter of the conductive metal particles used in the present invention (D _50), not particularly limited. The particle size of the conductive metal particles may affect the sintering characteristics. For example, conductive metal particles having a large particle size may be sintered at a lower rate than conductive metal particles having a smaller particle size. From the viewpoint of the sintering speed, the conductive metal particles used in the present invention preferably have a weight average particle diameter (D ₅₀ ) of 0.1 μm to 10 μm. Alternatively, the weight average particle diameter (D ₅₀ ) of the conductive metal particles can be appropriately set to a suitable value in consideration of the conductive paste application method described later.

The “weight average particle diameter (D ₅₀ )” in the present invention means that 50% by weight of the conductive metal particles have a particle diameter equal to or less than that value. The weight average particle diameter (D ₅₀ ) in the present invention can be measured by a laser diffraction / scattering particle size analyzer (for example, Microtrack of Nikkiso Co., Ltd.).

  The conductive metal particles used in the present invention preferably have a purity of 98% or more. However, depending on the electrode pattern and the electrical requirements of the electrode obtained by firing, it is also possible to use metal or alloy particles having a lower purity.

  The content of the conductive metal particles in the light-receiving surface electrode pattern forming conductive paste is not particularly limited as long as the object of the present invention can be achieved. In one embodiment, electroconductive metal particle comprises 40 to 95 weight% of the electrically conductive paste for light-receiving surface electrode pattern formation. In another embodiment, the conductive metal particles may constitute 60 to 90% by weight of the light-receiving surface electrode pattern forming conductive paste.

(2-2) Glass frit There is no restriction | limiting in particular in the chemical composition of the glass frit used in this invention. Any glass frit used in the conductive paste for electronic materials can be used as the glass frit in the present invention. In one embodiment, particles such as lead silicate glass and lead borosilicate glass can be used as the glass frit. Lead silicate glass and lead borosilicate glass are preferred materials in terms of both the softening point range and glass weldability. Alternatively, lead-free glass such as zinc borosilicate can also be used as the glass frit of the present invention.

  In one embodiment, the conductive paste is properly sintered and wetted under conditions where the maximum temperature of the silicon substrate is 600-900 ° C. to ensure proper adhesion between the silicon substrate and the sintered electrode. In order to achieve, the glass frit of the present invention preferably has a softening point of 300-550 ° C. By having a softening point within the above range, the conversion efficiency of the solar cell due to the deterioration of the silicon substrate due to the molten glass frit is prevented, and a sufficient melt flow occurs during firing to cause the silicon substrate and the electrode. Adhesive strength between the two can be obtained. Moreover, it becomes possible to achieve sufficient liquid phase sintering of the conductive metal particles by having a softening point within the above range.

  The “softening point” of the glass frit according to the present invention can be measured according to the fiber elongation method of ASTM C338-57.

  The content of the glass frit in the light-receiving surface electrode pattern forming conductive paste is not particularly limited as long as the object of the present invention can be achieved. In one embodiment, the glass frit constitutes 0.5 to 10.0% by weight of the light-receiving surface electrode pattern forming conductive paste. In another embodiment, the glass frit may constitute 1.0 to 3.0% by weight of the light-receiving surface electrode pattern forming conductive paste. By using a glass frit having a content within the above range, sufficient adhesion strength between the silicon substrate and the electrode can be obtained, and at the same time, the soldering for connection to an external circuit is hindered. It is possible to prevent so-called “glass floating” (a glass layer is formed on the electrode surface).

(2-3) Lead-tellurium-containing composite oxide The light-receiving surface electrode pattern forming conductive paste of the present invention may contain a lead-tellurium-containing composite oxide instead of the glass frit. The lead-tellurium-containing composite oxide that can be used in the present invention includes, for example, 35 to 85% by weight of PbO, 4 to 60% by weight of TeO ₂ , and 0.1 to 6% by weight of B ₂ O ₃ . . The lead-tellurium-containing composite oxide that can be used in the present invention includes, as optional components, 0 to 5 wt% TiO ₂ , 0 to 15 wt% Bi ₂ O ₃ , and 0 to 20 wt% PbOF. ₂ and / or 0 to 2% by weight of Li ₂ O.

  The content of the lead-tellurium-containing composite oxide in the light-receiving surface electrode pattern forming conductive paste is not particularly limited as long as the object of the present invention can be achieved. In one embodiment, the lead-tellurium-containing composite oxide constitutes 0.5 to 7.0% by weight of the light-receiving surface electrode pattern forming conductive paste. In another embodiment, the lead-tellurium-containing composite oxide may constitute 1.0 to 3.0% by weight of the light-receiving surface electrode pattern forming conductive paste. By using the lead-tellurium-containing composite oxide having a content within the above range, sufficient adhesion strength between the silicon substrate and the electrode can be obtained, and at the same time, the molten lead-tellurium-containing composite oxide can be obtained. It is possible to prevent a decrease in light transmittance due to oozing out on the surface of the silicon substrate.

(2-4) Organic Vehicle The “organic vehicle” in the present invention includes a polymer that is a resin binder, an organic liquid, and a mixture thereof. In the conductive paste for forming a light-receiving surface electrode pattern of the present invention, it is preferable to use a mixture of a polymer as a resin binder and an organic liquid as the organic vehicle.

  There is no particular limitation on the polymer that can be used in the organic vehicle of the present invention. Polymers that can be used include, for example, resins such as polymethacrylate, or cellulose derivatives such as ethylcellulose.

  There is no particular limitation on the organic liquid that can be used in the organic vehicle of the present invention. Organic liquids that can be used include alcohols; esters of alcohols (eg acetate or propionate); ethylene glycol monobutyl ether monoacetate; terpenes such as pine oil, terpineol.

  Preferred organic vehicles in the present invention are terpineol solution of ethyl cellulose, pine oil solution of resin (polymethacrylate, etc.), ethylene glycol monobutyl ether monoacetate solution of resin, pine oil solution of ethyl cellulose, ethylene glycol monobutyl ether monoacetate solution of ethyl cellulose, etc. including. A particularly preferred organic vehicle is a terpineol solution of ethylcellulose containing 5% to 50% by weight of ethylcellulose.

  In one embodiment, the organic vehicle constitutes 5 to 50% by weight of the light-receiving surface electrode pattern forming conductive paste.

(2-5) Other components (additives)
The conductive paste for forming a light-receiving surface electrode pattern according to the present invention is provided with a thickener (thickener), a stabilizer, a dispersant, a wetting agent, an antifoam, which are generally used in the art, if necessary. One or more additives such as an agent, a plasticizer, and a thinning agent (thinner) may be further included. For example, the above organic liquid or water can be used as a thinning agent (thinner). The content of the additive is appropriately determined by those skilled in the art depending on the properties of the conductive paste finally obtained.

(2-6) Physical properties of conductive paste In one embodiment, the light-receiving surface electrode pattern forming conductive paste of the present invention preferably has a viscosity of 50 to 400 Pa · s. The viscosity of the conductive paste can be adjusted by adding a thickener or a thinning agent (thinner). By having the viscosity of the conductive paste within the above range, appropriate coating characteristics are achieved while preventing separation due to sedimentation of inorganic particles (conductive metal particles, glass frit, and lead-tellurium-containing composite oxide). It becomes possible to do.

  The “viscosity” of the conductive paste in the present invention is measured using a Brookfield HBT viscometer equipped with a # 14 spindle and a utility cup under the conditions of 10 rpm and 25 ° C.

(2-7) Formation of Conductive Paste The light-receiving surface electrode pattern forming conductive paste of the present invention can be formed by mixing the above components using any means known in the art. it can. For example, the conductive paste can be formed by mixing with a three-roll kneader.

(3) Conductive paste for forming electrode pattern on back side The conductive paste for back electrode pattern formation that can be used in the present invention mainly contains aluminum particles as conductive metal particles. The back surface electrode pattern forming conductive paste may further include the same material as the light receiving surface electrode pattern forming conductive paste as other components (glass frit, organic vehicle, additive) constituting the conductive paste. . For example, an aluminum-containing conductive paste commercially available for solar cells such as PV333 and PV322 by the present applicant can be used as the conductive paste for forming the back electrode pattern.

  In addition to forming the electrode pattern to be the main electrode on the back using the conductive paste for forming the back electrode pattern, a paste containing silver particles or a mixture of silver particles and aluminum particles as conductive metal particles is used. Thus, an external connection terminal that is electrically connected to the main electrode may be formed. By using the above paste, it is possible to facilitate soldering to the external connection terminals.

  The back electrode pattern forming conductive paste and the external connection terminal forming conductive paste can be formed using the same method as the light receiving surface electrode pattern forming conductive paste.

(4) Formation of Electrode Pattern As shown in FIG. 1A, a light-receiving surface electrode pattern is formed on the light-receiving surface of the silicon substrate 100 having the n-type layer 104 on the light-receiving surface side and the p-type layer 102 on the back surface side. By applying the conductive paste for the electrode, the electrode pattern 112 on the light receiving surface is formed. The electrode pattern 112 on the light receiving surface may be composed of a plurality of partial electrode patterns. Each of the plurality of partial electrode patterns may have a shape including, for example, a bus bar portion and a plurality of finger portions extending from the bus bar portion. By having such a shape, it is possible to reduce the series resistance of the solar cells without significantly reducing the light receiving area of the silicon substrate 100.

  On the other hand, as shown in FIG. 1B, an electrode pattern 122 on the back surface is formed by applying a back electrode pattern forming conductive paste to the back surface of the silicon substrate 100. The electrode pattern 122 on the back surface is formed so as to cover almost the entire back surface of the silicon substrate.

  In the embodiment for forming the external connection terminal, for example, after applying the back electrode pattern forming conductive paste to form the electrode pattern 122 to be the main electrode on the back surface, as shown in FIG. The external connection terminal electrode pattern 124 may be formed by applying a connection terminal forming conductive paste. At this time, a part of the electrode pattern for external connection terminal 124 and a part of the electrode pattern 122 to be the main electrode on the back surface are overlapped, so that the main electrode 126 on the back surface and the external connection terminal 128 finally obtained are sufficient. It is desirable to realize a simple electrical connection (see FIG. 1D).

  Here, the formation of the electrode patterns (112, 122, and 124) using each conductive paste can be performed in an arbitrary order.

  There is no particular limitation on the means for forming the electrode pattern with each of the conductive pastes. The electrode pattern can be formed by using any coating method known in the art, such as coating by screen printing or coating by discharging from a nozzle unit such as a dispenser.

  Moreover, you may provide the process of drying an electrically conductive paste after formation of each electrode pattern by application | coating. The drying temperature of the conductive paste is preferably 180 ° C. or lower.

  Furthermore, in the embodiment in which the external connection terminal 128 is formed on the back surface of the silicon substrate 100, the electrode pattern 122 serving as the main electrode on the back surface desirably has a film thickness after drying of 20 μm to 40 μm. The external connection terminal electrode pattern 124 preferably has a post-drying film thickness of 15 μm to 30 μm on the silicon substrate. Furthermore, the overlapping portion of the electrode pattern 122 serving as the main electrode and the external connection terminal electrode pattern 124 preferably has a width of about 0.5 mm to about 2.5 mm.

Step (b) Electrode Pattern Baking Step Next, each electrode pattern (electrode pattern 112 on the light receiving surface, electrode pattern 122 serving as the main electrode on the back surface, and electrode pattern 124 for external connection terminals) formed in step (a). (If present) is fired to form each electrode (light-receiving surface electrode 114, back main electrode 126, and external connection terminal 128 (if present)) as shown in FIG. 1 (d). The firing of each electrode pattern can be performed using any means known in the art (such as an infrared belt firing furnace).

  In one embodiment, it is preferable to perform firing under conditions where the maximum temperature reached by the silicon substrate is 600 ° C to 900 ° C. By using the highest temperature within the above range, the glass component is sufficiently melted so that the silicon substrate 100 and each electrode (the light receiving surface electrode 114, the back surface main electrode 126, and the external connection terminal 128 (if present)) At the same time, it is possible to suppress the damage of the silicon substrate 100 due to the penetration of the glass component, the conductive metal component, etc. contained in the conductive paste, thereby preventing the light conversion efficiency from being lowered. It becomes.

  In one embodiment, it is preferable that the total time of the baking step (time from the start of heating to the end of heating, IN-OUT time) is about 1 to 2 minutes.

Step (c) Flash Lamp Light Irradiation Step Next, the laminate obtained in the step (c) is irradiated with flash lamp light from the light receiving surface side.

  The flash lamp used in the present invention has a very short light emission time on the order of milliseconds, and can instantaneously heat the irradiation target. The flash lamp used in the present invention includes a xenon flash lamp in which xenon gas is sealed, an argon flash lamp in which argon gas is sealed, a krypton flash lamp in which krypton gas is sealed, and the like. In particular, a xenon flash lamp is preferred in view of the fact that a large amount of light and a high luminous flux can be obtained instantaneously and that repeated light emission is easy.

In one embodiment, the flash lamp light is irradiated, it preferably has a light energy density of ^{0.2J / cm 2 ~100J / cm 2} . In another embodiment, the flash lamp light is irradiated, it preferably has a light energy density of ^{5J / cm 2 ~30J / cm 2} . By using flash lamp light having a light energy density within the above range, the irradiation effect of flash lamp light can be sufficiently exerted, and at the same time, by penetration of glass components, conductive metal components, etc. contained in the conductive paste. It is possible to suppress damage to the silicon substrate 100, thereby preventing an increase in series resistance and thus a decrease in light conversion efficiency.

  In one embodiment, the irradiated flash lamp light preferably has an irradiation time (pulse width) per time of 0.01 ms to 100 ms. In another embodiment, the irradiated flash lamp light preferably has an irradiation time (pulse width) per time of 10 ms to 70 ms. By using flash lamp light having an irradiation time (pulse width) per one time within the above range, the irradiation effect of flash lamp light is sufficiently exhibited, and at the same time, the glass component contained in the conductive paste, conductive It is possible to suppress damage to the silicon substrate 100 due to permeation of the conductive metal component and the like, thereby preventing an increase in series resistance and, consequently, a decrease in light conversion efficiency.

  Moreover, it is preferable that the number of times of irradiation of the flash lamp light is about 1 to 6 times. By using the number of times of irradiation within the above range, the irradiation effect of the flash lamp light can be sufficiently exhibited and at the same time, damage to the silicon substrate 100 can be suppressed.

  In the present invention, the laminate after firing by irradiating flash lamp light without changing the characteristics (such as the softening point of the glass frit) and firing conditions (such as firing temperature and firing time) of the conductive paste used. By instantaneously heating, damage to the silicon substrate 100 due to additional heating is suppressed. Then, by adopting the flash lamp light irradiation step, the series resistance of the obtained solar cell is mainly reduced, thereby enabling efficient production of solar cells having excellent light conversion efficiency.

The solar battery cell of the present invention manufactured by the method described above has excellent light conversion efficiency (EFF (%)). More specifically, the solar battery cell of the present invention has a small series resistance (Ω · cm ² ) and a high fill factor (fill factor, FF (%)).

Example 1
(1) Preparation of light-receiving surface electrode pattern forming conductive paste A A mixture containing silver particles and lead borosilicate glass frit (softening point 450 ° C.) was prepared. To this mixture was added a terpineol solution containing 20% by weight of ethylcellulose as an organic vehicle. Furthermore, the viscosity of the mixture was adjusted by adding terpineol as a thinner and a viscosity modifier mainly composed of bis [2- (2-butoxyethyl) ethyl] adipate. The content of each component is shown in Table 1.

  The obtained mixture was premixed with a universal mixer and then kneaded with a three-roll kneader to obtain a conductive paste A for forming a light receiving surface electrode pattern.

(2) Production of Solar Cell A 6-inch (about 15.24 cm) square silicon substrate having an n-type layer on the light-receiving surface side and a p-type layer on the back surface side was prepared. First, using a screen printing method, a conductive paste for forming external connection terminals (silver paste) is applied to the back surface side of the silicon substrate, dried at a temperature of 120 ° C., and has a film thickness after drying of 20 μm. An electrode pattern for external connection terminals was obtained. Next, using a screen printing method, a conductive paste for forming a back electrode pattern (containing aluminum, PV333 (manufactured by the present applicant)) is applied to the back side of the silicon substrate and dried at a temperature of 120 ° C. The electrode pattern for external connection terminals having a film thickness after drying of 35 μm was obtained. Here, a part of the electrode pattern serving as the main electrode was overlapped with a part of the electrode pattern for the external connection terminal.

  Next, the conductive paste A for forming a light-receiving surface electrode pattern was applied to the light-receiving surface side of the silicon substrate by screen printing, followed by drying to obtain an electrode pattern on the light-receiving surface. Screen printing of the conductive paste A was performed using a screen printing machine manufactured by Neurong and a 350 mesh mask made of stainless wire with a 45 cm × 45 cm frame. The obtained electrode pattern on the light receiving surface was a 6.0 inch square evaluation pattern comprising two bus bar portions having a width of 2 mm and a plurality of finger portions having a width of 70 μm and branched from the bus bar.

  Next, the obtained electrode pattern was co-fired in an infrared firing furnace under conditions of a maximum temperature of about 730 ° C. and an IN-OUT time of about 1.3 minutes. The obtained light-receiving surface electrode had a film thickness after firing of 13 μm.

Next, a xenon flash lamp light having a light energy density of 12 J / cm ² and an irradiation time (pulse width) of 30 msec was irradiated once from the light receiving surface side of the laminated body to obtain a solar battery cell. The flash lamp was irradiated at room temperature using a flash lamp irradiation device (SUS462 (manufactured by USHIO INC.)).

(Examples 2 to 6)
Except that the flash lamp light irradiation conditions were changed as shown in Table 3, the procedure of Example 1 was repeated to obtain solar cells.

(Example 7)
The size of the silicon substrate is 1.5 inches (about 3.81 cm) square, the electrode pattern is formed on the light receiving surface under the following conditions, and the irradiation conditions of the flash lamp light are listed in Table 3. Except that it changed as follows, the procedure of Example 1 was repeated and the photovoltaic cell was obtained.

  The conductive paste A was screen-printed using a screen printer manufactured by Price Co., Ltd. and a stainless steel wire 250 mesh mask of 8 inch × 10 inch frame to obtain an electrode pattern on the light receiving surface. The obtained electrode pattern on the light-receiving surface was a 1.5 inch (about 3.81 cm) square evaluation pattern consisting of a bus bar portion having a width of 2 mm and a plurality of finger portions having a width of 100 μm and branched from the bus bar. It was.

(Example 8)
The following light-receiving surface electrode pattern forming conductive paste B was used in place of the light-receiving surface electrode pattern forming conductive paste A, and the flash lamp light irradiation conditions were changed as shown in Table 3. Except for, the procedure of Example 1 was repeated to obtain solar cells.

The light-receiving surface electrode pattern forming conductive paste B is a lead borosilicate glass frit made of 44.51 wt% PbO, 47.74 wt% TeO ₂ , 0.48 wt% B ₂ O ₃ , 6. 83 wt% Bi ₂ O _3, and lead consist 0.44 wt% of Li ₂ O - to the change in the tellurium-containing composite oxide, and was modified as described the composition ratio of each component in table 2 Except this, it prepared in the procedure similar to the electrically conductive paste A for light-receiving surface electrode pattern formation.

(Comparative Examples 1-8)
Except having not performed irradiation of flash lamp light, the procedure of Examples 1-8 was repeated and the photovoltaic cell of Comparative Examples 1-8 was formed.

(Evaluation)
Using a cell tester (NCT-M-150AA manufactured by NPC), the electrical characteristics (IV characteristics) of the solar cells obtained in Examples 1 to 8 and Comparative Examples 1 to 8 were measured. The light conversion efficiency (EFF (%)) of the battery cell was determined. The results are shown in Table 3.

  From comparison between Examples 1 to 8 and Comparative Examples 1 to 8, it was revealed that the light conversion efficiency (EFF (%)) of the solar battery cell was improved by irradiation with flash lamp light.

DESCRIPTION OF SYMBOLS 100 Silicon substrate 102 P-type layer 104 N-type layer 112 Electrode pattern on light-receiving surface 114 Light-receiving surface electrode 122 Electrode pattern used as back main electrode 124 Electrode pattern for external connection terminal 126 Back surface main electrode 128 External connection terminal

Claims (7)

(A) applying a conductive paste containing conductive metal particles on a silicon substrate and forming electrode patterns on the light-receiving surface and the back surface of the silicon substrate;
(B) firing the electrode pattern formed in the step (a);
(C) irradiating the fired electrode pattern formed on the light receiving surface in the step (b) with light from a flash lamp, and the maximum temperature reached by the silicon substrate in the step (b) is 600. A method for producing a solar battery cell, characterized in that the temperature is from 0C to 900C.   The method of manufacturing a solar cell according to claim 1, wherein the flash lamp is a xenon flash lamp.   The method for producing a solar battery cell according to claim 1, wherein in the step (c), the light irradiation time of the flash lamp per time is 0.01 to 100 msec. ^{2. The} method for producing a solar battery cell according to claim 1, wherein in step (c), the energy density of light of the flash lamp is 0.2 to 100 J / cm ² .   2. The solar cell according to claim 1, wherein the conductive paste for forming an electrode pattern on the light receiving surface further includes a glass frit, and the glass frit has a softening point of 300 ° C. to 550 ° C. 3. Production method.   The method for manufacturing a solar cell according to claim 1, wherein the conductive paste for forming an electrode pattern on the light receiving surface further contains a lead-tellurium-containing composite oxide.   The method for producing a solar battery cell according to claim 1, wherein the conductive metal particles constitute 40 to 95% by weight of the conductive paste.

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