JP2010171370A - Solar cell element, solar cell module, and solar power generating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solar cell element which has high reliability, to provide a solar cell module, and to provide a solar power generating apparatus using the same. <P>SOLUTION: The solar cell element 3 includes a semiconductor substrate 20 having a first surface for receiving light and a second surface being the opposite side from the first surface, a first electrode 22 provided on the first surface of the semiconductor substrate 20, and a plurality of second electrodes 25 each including a first portion 25a fitted with an inner lead and a second portion 25b extending toward the side of the first portion 25a, and arranged at an interval on the second surface of the semiconductor substrate 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a solar cell element, a solar cell module, and a solar power generation device.

  In recent years, the demand for solar cells for home use tends to increase remarkably from the viewpoint of environmental protection.

  In the solar cell module, a plurality of solar cell elements connected in series or in parallel by inner leads are sealed with a filler between the translucent substrate and the back sheet.

  Such a solar cell element has a pn junction, and is formed on the front and back surfaces of a semiconductor substrate made of single-crystal silicon or polycrystalline silicon, with a front-side electrode and a back-side electrode made of a metal-based material. It has an electrode.

JP 2006-210654 A JP 2003-273377 A

  In recent years, in order to meet the demand for cost reduction of solar cell elements, thinning of single crystal silicon substrates and polycrystalline silicon substrates has been studied. With the thinning, solar cell modules are manufactured, stored and transported. However, there is a problem that cracks are likely to occur in the surface layer of the substrate due to the influence of thermal stress that causes the electrode to expand or contract due to heat or the like. For example, when the inner lead is connected to the back surface side electrode by soldering, a contraction stress is applied such that the surface of the substrate warps in a convex shape, and the surface layer portion of the substrate located in the vicinity of the surface side electrode is easily peeled off. When such a solar cell element is used, there is a problem that a defect occurs in output and the reliability is low.

  In particular, when using lead-free solder such as Sn-Ag that does not substantially contain lead in consideration of environmental considerations, the melting point of the solder increases, so the influence of heat increases and the surface layer of the substrate increases. It was easy to be missing. In this case, in particular, the boundary portion between the surface side electrode and the substrate tends to be chipped.

  The present invention has been devised to solve the above-described problems, and an object thereof is to provide a highly reliable solar cell element, a solar cell module using the solar cell element, and a solar power generation device.

  A solar cell element according to an aspect of the present invention includes a semiconductor substrate having a first surface that receives light and a second surface on the back side of the first surface, and the first surface of the semiconductor substrate. A first portion provided with an inner lead; and a second portion extending laterally of the first portion, the first portion of the semiconductor substrate being spaced apart from each other. A plurality of second electrodes arranged on the second surface.

  A solar cell module according to an aspect of the present invention is characterized in that a plurality of the solar cell elements are electrically connected.

  A solar power generation device according to an aspect of the present invention is characterized in that one or more of the solar cell modules are used as power generation means.

  According to the solar cell element, the solar cell module, and the solar power generation device according to one aspect of the present invention, the stress applied to the substrate located in the vicinity of the back surface side electrode can be reduced because the configuration described above is provided. It is possible to reduce the peeling of the surface layer portion. Therefore, a highly reliable solar cell element can be obtained.

  In addition, by using lead-free solder, it is possible to provide a solar cell element, a solar cell module, and a solar power generation device with higher reliability in consideration of the environment.

(A) is a top view which shows one Embodiment of a solar cell module, (b) is an exploded sectional view of (a). (A) is a top view which shows one Embodiment of a solar cell element, (b) is a back view of (a). It is the A section enlarged view of Drawing 2 (b). (A) is the B section enlarged view of FIG. 3, (b) shows the structure of the cross section in XX 'of (a). It is a top view which shows one Embodiment of a solar cell element. It is a top view which shows an example of the information display in a solar cell element. It is a block diagram which shows an example of a solar power generation device.

  Hereinafter, a solar cell element, a solar cell module, and a solar power generation device according to this embodiment will be described with reference to the drawings.

  A solar cell element is an individual element that generates light by receiving light, and a solar cell module is formed by connecting a plurality of solar cell elements to each other.

<Solar cell module>
As shown in FIG. 1, the solar cell module 1 includes a plurality of solar cell elements 3 and inner leads 4 as inter-element connection portions.

  The plurality of arrayed solar cell elements 3 are arranged in a substantially rectangular frame 5, and the translucent substrate 2 and the back sheet 14 fitted in the frame 5 so as to cover both sides of the solar cell element 3. Between the light receiving surface side filler 12 and the back surface side filler 13. As the translucent substrate 2, a glass plate, a transparent resin plate, or the like can be used.

  The inner lead 4 is formed of a long conductive member having the same width as or smaller than the output extraction portion 21 of the first electrode provided on the light receiving surface side of the solar cell element 3 shown in FIG. Is formed. Then, in each row in which the plurality of solar cell elements 3 are arranged, they are connected to the output extraction portion 21 of the first electrode and the first portions 25a of the plurality of second electrodes 25 shown in FIG. 2 by soldering or the like. Yes. As a result, the inner lead 4 includes the output extraction portion 21 of the first electrode of the solar cell elements facing each other and the first portions 25a of the plurality of second electrodes 25 between the solar cell elements 3 adjacent to each other. Are electrically connected.

  As such an inner lead 4, for example, a strip-shaped copper or aluminum foil having a thickness of about 0.1 to 0.4 mm and a width of about 2 mm and whose entire surface is covered with solder can be used. By using the solder-coated inner lead 4, it is easy to reduce the deterioration of the inner lead 4 due to oxidation or the like and the increase in resistance.

  Then, the inner lead 4 is soldered to the first electrode 21 of the solar cell element 3 or the first portion 25a of the second electrode 25 using hot air or a soldering iron or using a reflow furnace or the like. can do. In consideration of the environment, it is preferable that the solder is lead-free solder which does not substantially contain lead. Lead-free solders include Sn-Ag, Sn-Ag-Cu, Sn-Bi, Sn-Bi-Ag, Sn-Cu-Bi, Sn-Cu, Sn-Zn-Bi, Sn -Sb system can be preferably used.

  The light-receiving surface side filler 12 and the back surface side filler 13 are made of, for example, an ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) or polyvinyl butyral (PVB), and have a sheet shape with a thickness of about 0.4 to 1 mm. The one molded into is used. These are softened and fused by being heated and pressed under reduced pressure by a laminating apparatus, and are integrated with other members.

  As the back sheet 15, a fluorine resin sheet sandwiching an aluminum foil, a polyethylene terephthalate (PET) sheet deposited with alumina or silica, or the like is used.

  An example of the manufacturing method of the above-described solar cell module 1 will be described. First, a plurality of solar cell elements 3 (strings) to which the inner leads 4 are connected are prepared by soldering or the like.

  Next, the light receiving surface side filler 12 is placed on the translucent substrate 2, and the solar cell element 3 connected by the inner leads 4 is placed thereon. Furthermore, the back surface side filler 13 and the back surface sheet 14 are laminated | stacked in order on it. In such a state, they are set in a laminator and heated at 100 to 200 ° C., for example, for 15 minutes to 1 hour while being pressurized under reduced pressure, so that they are integrated to form the solar cell module 1.

<Solar cell element>
FIG. 2A is a plan view of the solar cell element 3 according to this embodiment, and FIG. 2B is a back view of the solar cell element 3. FIG. 3 is an enlarged view of a portion A shown in FIG. 4A is an enlarged view of a portion B shown in FIG. 3, and FIG. 4B shows a cross section taken along line XX ′ of FIG. In the figure, the T direction indicates the longitudinal direction of the inner lead 4, and the S direction indicates the short direction of the inner lead 4.

  This solar cell element 3 includes a semiconductor substrate 20 having a first surface that receives light and a second surface on the back side of the first surface, and a first surface provided on the first surface of the semiconductor substrate 20. The second surface of the semiconductor substrate 20 includes an electrode, a first portion 25a to which the inner lead 4 is attached, and a second portion 25b extending to the side of the first portion 25a, spaced apart from each other. And a plurality of second electrodes 25 arranged in a row.

  The semiconductor substrate 20 is formed in a plate shape, here, a substantially square plate shape. The semiconductor substrate 20 is made of, for example, single crystal silicon or polycrystalline silicon. Inside the semiconductor substrate 20 is p-type silicon containing an impurity exhibiting p-type conductivity such as boron (B) and n-type silicon containing an impurity exhibiting n-type conductivity such as P (phosphorus). A pn junction part.

  An antireflection film may be provided on the light receiving surface side of the semiconductor substrate 20. This antireflection film is made of a film of silicon nitride or titanium oxide, plays a role of reducing the reflectance of light in a desired wavelength region and increasing the amount of photogenerated carriers, and the photocurrent density Jsc of the solar cell element 3. To improve.

  The first electrode includes an output extraction portion 21 and a current collection portion 22 that is provided so as to intersect with the output extraction portion 21 substantially perpendicularly and is narrower than the output extraction portion 21. The thickness of such a 1st electrode (output extraction part 21, the current collection part 22) is about 10-40 micrometers.

  The current collector 22 of the first electrode has a width of about 50 to 200 μm and has a role of collecting carriers generated in the semiconductor substrate 20.

  The output extraction unit 21 of the first electrode has a width of about 1.3 mm to 2.5 mm, and has a role of collecting carriers (electric power) collected by the current collection unit 22 and outputting them to the outside.

  A ground collector electrode 24 and a second electrode 25 are provided on the second surface of the semiconductor substrate 20. The thickness of the second electrode 25 is about 10 μm to 30 μm, and the width is about 3.5 mm to 7 mm.

  The base collector electrode 24 is provided on substantially the entire second surface of the semiconductor substrate 20 and has a plurality of openings 28 for exposing the semiconductor substrate 20. The thickness of the ground collector electrode 24 is about 15 μm to 50 μm.

  The first portion 25a of the second electrode 25 has a role of collecting carriers (electric power) collected by the base collector electrode 24 and the second portion 25b and outputting them to the outside. The second portion 25b has a role of transmitting carriers from the base collector electrode 24 to the first portion 25a.

  A plurality of the second electrodes 25 are arranged along the T direction to which the inner lead 4 is connected, and are located between each other (a region indicated by reference numeral 24a between the first portions 25a and a region indicated by reference numeral 30 between the second portions 25b). Open and arranged in a straight line. With such a configuration, it is possible to disperse and reduce the thermal stress that the electrode expands or contracts due to heat or the like during the manufacture, storage, and transportation of the solar cell module. Bonding strength can be improved. Therefore, the force exerted on the semiconductor substrate 20 by the second electrode 25 can be reduced, and peeling of the surface layer portion of the semiconductor substrate 20 can be reduced to provide a highly reliable solar cell element. In particular, even when lead-free solder is used as the solder used for soldering the inner lead 4, the structure of this embodiment can reduce the problem that a very thin surface layer portion of the substrate 20 is peeled off.

  The first portion 25 a is provided across the base collector electrode 24 and the second surface of the semiconductor substrate 20 exposed from the opening 28 of the base collector electrode 24. Therefore, a portion 24a of the base collector electrode is disposed between the first portions 25a of the plurality of second electrodes 25.

  The second portion 25 b is formed continuously with the first portion 25 a and is provided on the base collector electrode 24. In FIG. 4A, the second portion 25b is provided on both sides of the first portion 25a, and in order to increase the contact area with the base collector electrode 24, the directions are opposite to each other (T direction, -T direction). ). Further, the second portion 25 b has a plurality of openings 27. By having the opening 27, the effect of stress dispersion and reduction can be improved.

  The inner lead 4 is connected to the first portions 25a of the plurality of second electrodes 25 in the solar cell element. Therefore, since the inner lead 4 includes a region that is not partially soldered to the solar cell element 3, after soldering, the inner lead 4 is formed on the semiconductor substrate 20 due to a difference in thermal expansion coefficient between the inner lead 4 and the substrate 20. The generated stress can be absorbed by deformation of a portion of the inner lead 4 that is not soldered, and the stress can be reduced.

  Furthermore, due to the difference in thermal expansion coefficient between the inner lead 4 and the semiconductor substrate 20, the semiconductor substrate 20 is likely to warp in a direction in which the light receiving surface side of the semiconductor substrate 20 is convex. Due to this warpage, the base collector electrode 24a between the first portions 25a of the plurality of second electrodes 25 and the inner lead 4 are easily in contact with each other. As a result, the carrier moves to the inner lead 4 at the contact portion between the base collecting electrode 24a and the inner lead 4, and the series resistance component of the first portions 25a of the plurality of discontinuous second electrodes 25 is not greatly increased. Stress can be reduced.

  As shown in FIG. 3, the width of the opening 28 of the base collector electrode 24 in the direction T is such that the opening 28 (width J) at the end of the semiconductor substrate 20 is located closer to the center than the end. Greater than width K). Accordingly, the first portion 25a of the second electrode 25 is in contact with the semiconductor substrate 20 with a larger area when it is located on the end side of the semiconductor substrate 20 than when it is located on the center side. By adopting such a configuration, for example, when the both ends of the string are lifted at the time of module manufacture, even when stress is applied to the solar cell element by the inner lead 4, the second electrode 25 and the substrate 20 are joined. The strength is increased and the second electrode 25 is difficult to peel off from the semiconductor substrate 20.

  Also, as shown in FIG. 3, the width of the opening 28 of the base collector electrode 24 in the direction S is such that the opening 28 (width I) at the end of the semiconductor substrate 20 is located closer to the center than the end. Greater than width H). Accordingly, the first portion 25a of the second electrode 25 is in contact with the semiconductor substrate 20 with a larger area when it is located on the end side of the semiconductor substrate 20 than when it is located on the center side. By adopting such a configuration, for example, even when the inner lead 4 is inclined and disposed at the time of module manufacture, the peripheral portion of the first portion 25 a of the second electrode 25 is not on the base collector electrode 24. In addition, the bonding strength becomes strong and it is difficult to peel off from the substrate 20.

  In FIG. 3, one of the openings 28 on the end side of the semiconductor substrate 20 has a trapezoidal shape. By adopting such a configuration, even when the inner lead 4 is disposed at an inclination, the bonding strength is increased and it is difficult to peel off from the substrate 20.

  In FIG. 3, the first portion 25 a of the second electrode 25 is not provided in the central region C of the semiconductor substrate 20. Further, the second portion 25 b of the second electrode 25 provided in the central region C of the semiconductor substrate 20 is compared with the second portion 25 b of the second electrode 25 provided at the end of the semiconductor substrate 20. long. The stress at the time of soldering the inner lead 4 is generally easily generated in the central region C of the solar cell element. For this reason, the first portion 25a is not provided in the central region C, and the second portion 25b is further grounded. By adopting a configuration in which the electrode 24 is in contact with a large area, it is possible to reduce the peeling of the second electrode 25 while reducing the stress caused by the inner lead 4.

  4A, the width K in the direction T of the opening 28 of the base collector electrode 24 is larger than the width L of the first portion 25a of the second electrode 25. As shown in FIG. Therefore, when attention is paid to the opening 28, there are a region where the first portion 25a of the second electrode 25 is formed and a region 28a where the substrate is exposed on both sides in the T direction of the region. With such a configuration, even if stress is generated due to the difference in thermal expansion coefficient between the inner lead 4 and the substrate 20 after the inner lead 4 is soldered, the first of the second electrode 25 is made. Since the peripheral portion of the portion 25 a is not on the base collector electrode 24, the bonding strength is increased and it is difficult to peel off from the substrate 20. Further, since the first portion 25a of the second electrode 25 is provided on the semiconductor substrate 20 in the T direction, the bonding strength of the first portion 25a can be strengthened.

  Further, the width Q of the first portion 25 a of the second electrode 25 is larger than the width R of the second portion 25 b in the width direction S of the inner lead 4.

  An example of the dimensions of each part is as follows. The width L in the T direction of the first portion 25a of the second electrode 25 is about 1 to 3 mm, and the width N in the T direction of the opening 27 provided in the second portion 25b is about 0.5 to 1 mm. The width M in the T direction between the openings 27 is about 0.1 to 0.7 mm. The interval between the second portions 25b of the plurality of second electrodes 25 is about 0.5 to 2 mm. Furthermore, the width Q in the S direction of the first portion 25a of the second electrode 25 is about 3 to 5 mm, and the width R in the S direction of the second portion 25b is about 1 to 4 mm. The width H in the S direction of the opening 28 is about 2 to 5 mm.

<Method for producing solar cell element>
An example of the manufacturing method of the above-described solar cell element 3 will be described. First, a substrate having one conductivity type (here, p-type conductivity type) is prepared by doping a predetermined dopant (impurity for controlling the conductivity type) as a base substrate of the semiconductor substrate 20.

The base substrate exhibits p-type conductivity by, for example, doping B (boron) or Ga (gallium) as a dopant element to about 1 × 10 ¹⁵ to 1 × 10 ¹⁷ atoms / cm ^3. . Doping of the dopant element can be realized, for example, by dissolving the dopant element itself or a dopant material containing the dopant element in silicon in the silicon melt during the production of the silicon ingot.

  Thereafter, an uneven shape having a large number of fine protrusions is formed on the first surface side of the original substrate as necessary.

Next, a reverse conductivity type layer is formed. The reverse conductivity type layer is formed by diffusing a dopant exhibiting a reverse conductivity type into a predetermined portion of the original semiconductor substrate. For example, when a semiconductor substrate exhibiting a p-type conductivity is used, it is preferable to use P (phosphorus) as an n-type doping element for forming a reverse conductivity type layer. As a diffusion method, a coating thermal diffusion method in which P ₂ O ₅ in a paste state is applied to a predetermined formation target and thermally diffused, or POCl ₃ (phosphorus oxychloride) in a gas state is used as a diffusion source. For example, a vapor phase thermal diffusion method for diffusing to the formation target portion or an ion implantation method for directly diffusing p ⁺ ions to the formation target portion can be used.

  An antireflection film may be formed on the surface of the substrate. As a method for forming the antireflection film, PECVD (plasma enhanced chemical vapor deposition), vapor deposition, sputtering, or the like can be used. In addition, the antireflection film may be formed after the output extraction portion 21 and the current collector 22 are formed.

Next, a highly doped layer is formed on the back side of the substrate. For example, when boron is used as a dopant element, a high-concentration doped layer can be formed by a thermal diffusion method using BBr ₃ (boron tribromide) as a diffusion source under a temperature condition of about 800 to 1100 ° C. For example, when aluminum is used as a dopant element, an aluminum paste containing aluminum powder and an organic vehicle is applied to the back surface of the substrate by a printing method, and then heat-treated (fired) at a maximum temperature of about 700 to 850 ° C. Then, the heavily doped layer can be formed by diffusing aluminum on the back surface of the substrate. In the case of the latter method, it can be used as it is as the base collector electrode 24 without removing the aluminum layer formed on the back surface after firing.

  Next, the output extraction part 21 and the current collection part 22 which comprise a surface electrode are formed. The output extraction part 21 and the current collection part 22 are formed using a coating method. Specifically, for example, a conductive paste in which 10 to 30 parts by weight of an organic vehicle and 0.1 to 10 parts by weight of glass frit are added to 100 parts by weight of metal powder such as silver is used as the first paste of the semiconductor substrate 12. After the coating film is formed by coating on a predetermined region of the surface 12a, the coating film is baked at a maximum temperature of 600 to 850 ° C. for several tens of seconds to several tens of minutes, whereby a light receiving surface side electrode can be formed. . As the coating method, a screen printing method or the like can be used. Preferably, after coating, the solvent is evaporated at a predetermined temperature and dried.

  Subsequently, the base collector electrode 24 is formed on the back surface of the substrate 20. The base collector electrode 24 can also be formed using a coating method. Specifically, a conductive paste in which 10 to 30 parts by weight of an organic vehicle and 0.1 to 5 parts by weight of glass frit is added to 100 parts by weight of metal powder such as aluminum or silver is formed on the back surface of the semiconductor substrate 20. A coating film is formed by coating almost the entire region. As a coating method, a screen printing method or the like can be used. Preferably, after coating, the solvent is evaporated at a predetermined temperature and dried. As described above, when a conductive paste containing aluminum is used, the high-concentration doped layer and the base collector electrode 24 can be formed simultaneously.

  Next, the second electrode 25 is formed on the back surface side of the semiconductor substrate 20. The second electrode 25 can also be formed using a coating method. Specifically, a conductive paste in which 10 to 30 parts by weight of an organic vehicle and 0.1 to 5 parts by weight of glass frit are added to 100 parts by weight of metal powder such as silver is applied in a predetermined pattern and applied. A film is formed. As a coating method, when the second electrode 25 is formed by printing a conductive paste by using screen plate making, the screen plate making pattern used so as to be printed in a shape as shown in FIG. By providing a gap or the like, the second electrode 25 can be formed. After application, the solvent is preferably evaporated and dried at a predetermined temperature. And an electrode can be formed by baking the board | substrate 20 for several dozen seconds-several tens of minutes at the maximum temperature of 600-850 degreeC in a baking furnace.

  At this time, in the second electrode 25, the portion provided on the opening 28 of the base collector electrode 24 and connected to the inner lead becomes the first portion 25a, and the portion formed in the shape having the opening 27 is formed. A second portion 25 b with the base collector electrode 24 is formed. The second electrode 25 is a back surface electrode formed in a plurality of island shapes having gaps (between the second portions 25b 30 and between the first portions 25a).

  In the above description, the electrode formation by the printing / firing method is used. However, it is also possible to form the electrode by using thin film formation such as vapor deposition or sputtering, or plating.

  As described above, the solar cell element according to this embodiment can be manufactured. Distributing and reducing the stress caused by the difference in the coefficient of thermal expansion between the second electrode 25 and the base collector electrode 24 during firing can be achieved by providing an interval without the plurality of second electrodes 25 being continuous. In addition, the bonding strength between the second portion 25b and the base collector electrode 24 can be improved.

  The present invention is not limited to the above embodiments, and many modifications and changes can be made within the scope of the present invention.

  For example, when the first electrode, the base collector electrode 24, and the second electrode 25 are formed by applying an Ag paste on the front surface and applying an Al paste and an Ag paste on the back surface, they may be fired simultaneously. The baking process may be performed separately. Further, the order of electrode formation is not particularly limited. Moreover, although the shape which apply | coated Ag paste and formed the 2nd electrode 25 after forming the base collector electrode 24 was demonstrated to the example, the reverse may be sufficient.

  In FIG. 4B, the first electrode is provided immediately below the second electrode 25, but the first electrode is formed differently depending on the cutting position in FIG.

<Granting information to solar cell elements>
Next, an example of giving information such as a production lot number to the solar cell element 3 will be described. For example, the case where the shape of the 2nd part 25a is used as an identification shape which shows information is demonstrated.

  As shown in FIG. 5, the second portion 25a of the second electrode 25 has a plurality of openings 27 as described above. One or more pieces of information regarding the solar cell element 3 are displayed by providing, for example, notches 33a and 33b as shown in a part of the region 32 between the opening 27 and the base collector electrode 24 in the second portion 25a. Can be made.

  For example, a rule is set in advance so that a symbol or a number corresponds to the position and number of the notch, etc., and various information is given by producing the notches 33a, 33b, etc. according to this rule. It becomes possible to do. Such cutouts 33a and 33b can be produced by providing cutouts in a screen plate-making pattern for printing a conductive paste.

  The information to be given to the solar cell element includes, for example, the manufacturing date of the solar cell element 3, the manufacturing lot number, the manufacturing lot number of the semiconductor substrate used, the manufacturing lot number of the screen plate making used, and the manufacturing of the conductive paste used. There are lot numbers.

  For example, as shown in FIG. 6, in the U1 portion, the manufacturing location of the solar cell element (including the manufacturing factory, production line, etc.), the year of manufacture in the U2 portion, the month of manufacture in the U3 portion, and the month of manufacture in the U4 portion The production lot number of the used screen-making plate can be displayed on the U5 portion opposite to the U1 portion.

  Thus, the information regarding the plurality of solar cell elements 3 can be clearly displayed by a simple method, and the history of the solar cell elements 3 can be easily known in a short time.

  In addition, although the example which provided the notch part as a shape of information provision was demonstrated, it is not limited to this, A protrusion shape etc. may be sufficient instead of a notch part, and these combination may be sufficient.

<Solar power generator>
The solar power generation device according to one aspect of the present invention uses one or more of the solar cell modules described above as power generation means, or power generation means having one or more of the solar cell modules and the power generation means. Power conversion means for converting DC power into AC power is provided.

  For example, as shown in FIG. 7, the solar power generation device 50 includes a solar cell module 40 as power generation means in which one or more of the solar cell modules are electrically connected, and generated power (DC power) of the solar cell module 40. Is input and converted into AC power. Note that there may be a plurality of solar cell modules 40, and the plurality of solar cell modules may be electrically connected to each other.

  The power conversion device 45 includes, for example, an input filter circuit 41, a power conversion circuit 42, an output filter circuit 43, and a control circuit 44. In this way, the DC power generated by the solar cell module 40 is converted into AC power by the power converter 45, and this AC power is input to the commercial power supply system 46. According to such a solar power generation device 50, since the solar cell module which comprises this has high reliability, the solar power generation device excellent in reliability can be provided.

1: Solar cell module 3: Solar cell element 20: Semiconductor substrate 22: First electrode 25: Second electrode 25a: First portion of second electrode 25b: Second portion of second electrode 50: Solar power plant

Claims (15)

A semiconductor substrate having a first surface for receiving light and a second surface on the back side of the first surface;
A first electrode provided on the first surface of the semiconductor substrate;
A first portion to which an inner lead is attached; and a second portion extending laterally of the first portion, and arranged on the second surface of the semiconductor substrate with a gap therebetween. And a plurality of second electrodes.   The solar cell element according to claim 1, wherein the plurality of second electrodes are arranged linearly.   3. The solar cell element according to claim 1, further comprising a base collector electrode provided on the second surface of the semiconductor substrate and having a plurality of openings exposing the semiconductor substrate.   The first portions of the plurality of second electrodes are provided across the base collector electrode and the second surface of the semiconductor substrate exposed from the opening of the base collector electrode, respectively. The solar cell element according to claim 3.   5. The solar cell element according to claim 3, wherein the opening of the base collector electrode is larger than the first portion of the second electrode in a longitudinal direction of the inner lead.   4. The width of the inner lead in the width direction of the inner lead is wider when the opening of the base electrode is located at the end side than at the center side of the semiconductor substrate. The solar cell element according to any one of 5.   The solar cell element according to claim 1, wherein the second part of the second electrode has a plurality of openings.   The shape of the said 2nd part was used as an identification shape which shows information, The solar cell element in any one of Claims 1-7 characterized by the above-mentioned.   9. The solar cell element according to claim 1, wherein the first portion of the second electrode is wider than the second portion in a short direction of the inner lead. .   The first portion of the plurality of second electrodes has a longer width in the longitudinal direction of the inner lead when it is located on the end side than that located on the center side of the semiconductor substrate. The solar cell element according to any one of claims 1 to 9.   The solar cell element according to claim 1, wherein the first portion of the second electrode is not provided in a central region of the semiconductor substrate. A plurality of solar cell elements according to any one of claims 1 to 11,
A solar cell module comprising: inner leads connected to the first portions of the second electrodes of the plurality of solar cell elements by lead-free solder.   A solar cell module comprising a plurality of the solar cell elements according to any one of claims 1 to 11 electrically connected.   A solar power generation apparatus using one or more of the solar cell modules according to claim 12 or 13 as power generation means.   14. A photovoltaic power generation apparatus comprising: power generation means having at least one of the solar cell modules according to claim 12; and power conversion means for converting DC power from the power generation means into AC power.

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