JP2015073121A - Solar battery cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar battery cell capable of materializing a long life and high efficiency.SOLUTION: A solar battery cell 10 includes: a semiconductor substrate 13; a plurality of finger electrodes 12 extending in parallel with each other on a light-receiving surface side of the semiconductor substrate 13; two or more surface bus bar electrodes 11a electrically connected to the plurality of finger electrodes 12, respectively and formed so as to intersect the finger electrodes 12; and two or more back surface bus bar electrodes 11b formed immediately below each surface bus bar electrode 11a, across the semiconductor substrate 13 on a non-light-receiving surface side of the semiconductor substrate 13. In the solar battery cell 10, between the adjacent surface bus bar electrodes 11a, each of the plurality of finger electrodes 12 is divided into a plurality of finger electrode fragments 12a, light-receiving surface electrode units 16a and 16b are configured by the respective surface bus bar electrodes 11a and the finger electrode fragments 12a, and width A of a divided part is 30 μm or more and 5000 μm or less.

Description

  The present invention relates to a solar battery cell.

  Solar cells are expected as a new energy source because they can directly convert clean and inexhaustible sunlight into electricity.

FIG. 6 is a schematic diagram showing a general structure of a solar battery cell in a solar battery, and specifically shows a structure of a surface of the solar battery cell exposed to sunlight. As shown in FIG. 6, a conventional solar battery cell 10 includes a semiconductor substrate 13, a surface bus bar electrode 5a provided on the light receiving surface side of the semiconductor substrate 13, and a plurality of fingers orthogonal to the surface bus bar electrode 5a. Electrode 5b.

In the conventional solar cell configured as described above, a plurality of finger electrodes 5b made of elongated lines are provided so as to be parallel over almost the entire width of the semiconductor substrate 13, and the surface bus bar electrodes 5a adjacent to each other by the finger electrodes 5b. Are electrically connected to each other.

Thus, in the technique described in Patent Document 1, the finger electrodes 5b are formed over almost the entire width of the surface of the solar battery cell, and the adjacent surface bus bar electrodes 5a are electrically connected to each other by the finger electrodes 5b. Therefore, each surface bus bar electrode 5a cannot uniformly collect the current from the finger electrodes 5b, and the load applied to the surface bus bar electrode 5a cannot be equally divided. There has been a problem that the deterioration rate becomes different and the lifetime of the solar battery cell is shortened.

Further, for example, as shown in FIG. 1A, when a defect occurs in the left side finger electrode 5b of the leftmost surface bus bar electrode 5a or the right end surface bus bar electrode 5a, as viewed from the front surface bus bar electrode 5a. Further, there is a problem that current from the finger electrode 5b on the edge side of the defect cannot be collected, and conversion efficiency is lowered due to insufficient current collection.

JP 2005-353851 A

This invention is made | formed in view of such a situation, and it aims at providing the photovoltaic cell which can implement | achieve lifetime improvement and efficiency improvement.

In order to achieve the above object, a solar cell 10 of the present invention includes a semiconductor substrate 13, a plurality of finger electrodes 12 extending parallel to each other on the light receiving surface side of the semiconductor substrate 13, and the plurality of the plurality of finger electrodes 12. Two or more surface bus bar electrodes 11a electrically connected to each of the finger electrodes 12 and formed so as to intersect with the finger electrodes 12, and on the non-light-receiving surface side of the semiconductor substrate 13, the semiconductor substrate 13 and two or more back surface bus bar electrodes 11b formed immediately below each of the front surface bus bar electrodes 12, and each of the plurality of finger electrodes 12 between the adjacent front surface bus bar electrodes 11a. Is divided into a plurality of finger electrode segments 12a, each of which is constituted by the respective surface bus bar electrodes 11a and the finger electrode segments 12a. More of the light-receiving surface electrode units 16a, 16b further has a width of the divided portions is 30μm or more 5000μm or less, and wherein.

In the solar battery cell 10 of the present invention, each of the plurality of finger electrodes 12 is divided into a plurality of finger electrode segments 12a between the adjacent surface bus bar electrodes 11a. Therefore, the life of the solar battery cell 10 can be extended. Moreover, it is preferable that the width | variety of the part parted is 30 micrometers or more and 5000 micrometers or less. Thereby, it comes to be divided reliably.

Further, in the solar battery cell 10 of the present invention, it is more preferable that the width of the divided portion is 30 μm or more and 2000 μm or less. By setting the width of the divided portion within such a numerical range, the area of the light receiving surface can be secured to the maximum, so that higher conversion efficiency can be maintained.

Moreover, in the photovoltaic cell 10 of this invention, it is preferable that the sum of the length of the said finger electrode piece 12a in the light-receiving surface electrode unit 16a and the light-receiving surface electrode unit 16b is substantially the same. With such a structure, the load applied to the surface bus bar electrode 11a becomes more uniform, the deterioration rate of the surface bus bar electrode 11a becomes more uniform, and the life of the solar battery cell 10 can be extended.

Moreover, the photovoltaic cell 10 of the present invention is a finger electrode connecting line that electrically connects the plurality of finger electrode segments 12a on the same side among the plurality of finger electrode segments 12a on both sides of the divided portion. 14 is preferable. With this structure, as shown in FIG. 4, when the finger electrode segment 12a has a defect, the current from the finger electrode segment 12a on the farther side of the defect as viewed from the surface bus bar electrode 11a Since it flows to the adjacent finger electrode segment 12a via the line 14, current can be collected without waste, and the conversion efficiency can be further increased.

Moreover, in the photovoltaic cell 10 of this invention, it is preferable that the width | variety of the said finger electrode connection line 14 is 20 micrometers or more and 200 micrometers or less. By setting the width of the finger electrode connecting line 14 within such a numerical range, the light receiving surface area can be ensured to the maximum, so that high conversion efficiency can be maintained.

Moreover, in the photovoltaic cell 10 of this invention, it is preferable to further have the frame line 15 which electrically connects the said several finger electrode mutually in each of the both ends of the said several finger electrode 12. FIG. As a result, when a defect (see FIG. 5) occurs in the finger electrode 12 on the left side of the surface bus bar electrode 11a at the left end or the right side of the surface bus bar electrode 11a at the right end, as viewed from the surface bus bar electrode 11a, Since the current from the finger electrode 12 on the edge side flows to the adjacent finger electrode 12 via the frame line 15, current can be collected without waste, and the conversion efficiency can be further increased.

In the solar battery cell of the present invention, it is preferable that 70 or more and 140 or less finger electrodes 12 are provided on the semiconductor substrate 13.
In the solar battery cell of the present invention, the finger electrode 12 preferably has a width of 20 μm or more and 90 μm or less.
In the solar battery cell of the present invention, the surface bus bar electrode 11a preferably has a width of 1 mm or more and 2 mm or less.

By making it within the numerical range as described above, the light receiving surface area can be ensured to the maximum, so that high conversion efficiency can be maintained.

The solar battery cell concerning embodiment of this invention is shown. Fig.1 (a) shows the light-receiving surface of a photovoltaic cell, FIG.1 (b) shows the non-light-receiving surface of a photovoltaic cell. It is sectional drawing which shows the interlayer structure of the photovoltaic cell concerning embodiment of this invention. It is a flowchart which shows the manufacturing method of the photovoltaic cell of this invention. The light-receiving surface electrode structure of the photovoltaic cell concerning another embodiment of this invention is shown. The light-receiving surface electrode structure of the photovoltaic cell concerning another embodiment of this invention is shown. The conventional solar cell is shown.

Hereinafter, embodiments of the solar battery cell 10 of the present invention will be described in detail with reference to the drawings.

In the drawings according to the embodiments of the present invention, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated in order to avoid duplication of description. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

The configuration of the solar battery cell 10 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a solar cell 10 according to one embodiment of the present invention, in which FIG. 1 (a) shows the light receiving surface of the solar cell 10, and FIG. 1 (b) shows the solar cell 10. A non-light-receiving surface is shown.

As shown in FIG. 1A and FIG. 1B, the solar cell 10 of the present invention includes a semiconductor substrate 13 and a plurality of parallel extending on the light receiving surface side of the semiconductor substrate 13. The finger electrode 12, the two or more surface bus bar electrodes 11 a electrically connected to each of the plurality of finger electrodes 12 and formed so as to intersect with the finger electrodes 12, and the non-conduction of the semiconductor substrate 13 On the light receiving surface side, there are two or more back surface bus bar electrodes 11b formed directly below each front surface bus bar electrode 12 with the semiconductor substrate 13 interposed therebetween. The back surface bus bar electrode 11b is electrically connected to the front surface bus bar electrode 11a of the adjacent solar cell 10 by an inner lead (not shown) or the like, thereby electrically connecting the plurality of solar cells 10 to each other. Can do.

Furthermore, in the photovoltaic cell 10 of the present invention, each of the plurality of finger electrodes 12 is divided into a plurality of finger electrode segments 12a between the adjacent surface bus bar electrodes 11a, and the surface bus bar electrodes 11a and the It further has two or more sets of light receiving surface electrode units 16a and 16b constituted by the finger electrode pieces 12a.

The interlayer structure of the solar battery cell 10 according to the embodiment of the present invention can be a structure used for a normal solar battery cell. As an example, a structure as shown in FIG. As shown in FIG. 2, the semiconductor substrate 13 includes a p-type silicon substrate 1, an n-type diffusion layer 2 provided in order toward the light receiving surface as viewed from the p-type silicon substrate 1, and an antireflection film 3. And can be included. Although not shown in FIG. 2, the finger electrode 12 and the surface bus bar electrode 11 a are provided on the antireflection film 3. The semiconductor substrate 13 can further include a backside bus bar electrode 11 b and a BSF layer 4 provided on the non-light-receiving surface side of the p-type silicon substrate 1.

Hereinafter, the interlayer structure of the solar battery cell 10 will be described in detail.

As the p-type silicon substrate 1, single crystal silicon, polycrystalline silicon, or the like can be used. A single crystal silicon substrate is formed by a pulling method or the like, and a polycrystalline silicon substrate is formed by a casting method or the like. The polycrystalline silicon substrate can be mass-produced and is more advantageous than the single crystal silicon substrate in terms of manufacturing cost. Here, the size of the p-type silicon substrate 1 is, for example, 140, 150, 155, 160, or 170 mm square. This magnitude may be within the range of any two values exemplified here.

The n-type diffusion layer 2 is formed on the p-type silicon substrate 1 by heat treatment in the diffusion furnace or the like on the light receiving surface side of the p-type silicon substrate 1. Specifically, the n-type diffusion layer 2 can be formed by diffusing phosphorus atoms, which are n-type impurities, over the entire surface portion of the p-type silicon substrate 1, and then the diffusion layer portions on the side surface portion and the bottom surface portion. Can be removed.

The antireflection film 3 is formed on the n type diffusion layer 2 with a silicon nitride film or the like on the light receiving surface side of the p type silicon substrate 1. The antireflection film 3 is formed by, for example, a plasma CVD method. This silicon nitride film has a passivation effect when formed, and has an effect of improving the conversion efficiency of the solar battery cell together with an antireflection function.

The BSF layer 4 is a reverse electric field region formed in the vicinity of the surface of the p-type silicon substrate 1 in order to prevent the generated carriers from disappearing due to recombination on the surface. The solar battery cell 10 according to the embodiment of the present invention has a function of repelling minority carriers that have moved to the back surface by using the BSF layer 4. The BSF layer 4 can be formed by screen printing an aluminum paste on the non-light-receiving surface side of the p-type silicon substrate 1.

Hereinafter, the electrode structure on the light receiving surface side of the solar battery cell 10 will be described in detail.

The electrodes of the solar battery cell 10 according to the embodiment of the present invention include a semiconductor substrate 13, a plurality of finger electrodes 12 extending parallel to each other on the light receiving surface side of the semiconductor substrate 13, and the plurality of fingers Two or more surface bus bar electrodes 11 a electrically connected to each of the electrodes 12 and intersecting with the finger electrodes 12, and the semiconductor substrate 13 on the non-light-receiving surface side of the semiconductor substrate 13 And two or more back surface bus bar electrodes 11b formed immediately below each of the front surface bus bar electrodes 12.

As shown in FIG. 1A, two surface bus bar electrodes 11a are formed so as to intersect with the finger electrodes 12, and have a function of collecting current flowing through the finger electrodes 12 at one end. Further, as shown in FIG. 1B, the back surface bus bar electrode 11b is formed on the non-light-receiving surface side of the semiconductor substrate 13, and the front surface bus bar electrode 11a of the adjacent solar cell 10 by an inner lead (not shown) or the like. It is possible to electrically connect the plurality of solar battery cells 10 to each other by being electrically connected to each other.

In FIG. 1, although it has the two surface bus-bar electrodes 11a as preferable embodiment of this invention, it is not necessarily this limitation. For example, it is possible to have two or more surface bus bar electrodes 11a.

The width of the surface bus bar electrode 11a is preferably 1 mm or more and 2 mm or less. When the width of the surface bus bar electrode 11a is less than 1 mm, the resistance in the surface bus bar electrode 11a is increased, which is not suitable. On the other hand, if it exceeds 2 mm, the resistance in the surface bus bar electrode 11a can be sufficiently reduced, but the conversion efficiency of the solar battery cell is reduced due to the excessive thickness and the decrease in the light receiving surface area due to the increase in the electrode area. This is unsuitable because it causes a decrease in.

Moreover, when providing two as the said surface bus-bar electrode 11a, it is more preferable to make the width | variety into 2 mm. Of course, it is also possible to provide three or more surface bus bar electrodes 11a. In this case, the width of the surface bus bar electrodes 11a can be appropriately provided within a range that does not affect the amount of light received by the solar battery cell 10. is there.

The back bus bar electrodes 11b are preferably provided with the same number and the same width as the front bus bar electrodes 11a. Further, as shown in FIG. 2, the front surface bus bar electrode 11 a and the back surface bus bar electrode 11 b are preferably provided so as to be vertically symmetrical in the cross-sectional view of the solar battery cell 10. Thus, by providing the front surface bus bar electrode 11a and the rear surface bus bar electrode 11b, it is possible to reduce the warpage that occurs when the bus bar electrodes 11a and 11b of the solar battery cell 10 are formed. Further, when electrically connecting the front surface bus bar electrode 11a of one solar battery cell and the rear surface bus bar electrode 11b of the other adjacent solar battery cell 10, the warpage of the solar battery cell tends to increase. By providing them symmetrically, the warpage occurring on the front and back surfaces of the solar battery cell 10 can be offset, and as a result, the warpage of the solar battery cell 10 can be efficiently reduced.

For the front bus bar electrode 11a and the back bus bar electrode 11b, for example, a metal such as Ag, Pt, Cu, or an alloy thereof can be used as an electrode material. A conductive paste similar to that of the finger electrode 12 may be used. As a foil-like thing, for example, a copper foil or a copper foil tin-plated, and in some cases, an adhesive is used.

A plurality of finger electrodes 12 are formed on the light receiving surface side of the semiconductor substrate 13 so as to extend in parallel with each other, and function to take out an electromotive force generated in the semiconductor substrate 1. As a width | variety of the finger electrode 12 in this invention, 20 micrometers or more and 90 micrometers or less are preferable. When the width of the finger electrode is less than 20 μm, the resistance in the finger electrode increases, which is not suitable. On the other hand, when the thickness exceeds 90 μm, the thickness becomes excessive, and the conversion area of the solar battery cell is reduced due to the decrease in the light receiving surface area due to the increase in the electrode area, which is not suitable.

Further, it is preferable that one solar battery cell 10 has 70 or more and 140 or less finger electrodes 12. When the number of finger electrodes is less than 70, the current flowing through the finger electrodes is not sufficient, and the conversion efficiency of the solar battery cell is lowered. On the contrary, when the number exceeds 140, the light receiving surface of the solar battery cell 10 is excessively covered, and the conversion area of the solar battery cell is reduced due to the decrease in the light receiving surface area due to the increase in the electrode area.

Moreover, the solar cell 10 of the present invention further includes two or more sets of light receiving surface electrode units 16a and 16b. Specifically, each of the plurality of finger electrodes 12 is divided into a plurality of finger electrode segments 12a between the adjacent surface bus bar electrodes 11a, and the respective surface bus bar electrodes 11a and the finger electrode segments 12a respectively The light receiving surface electrode units 16a and 16b are configured. Thereby, the load concerning each surface bus-bar electrode 11a is divided, and the lifetime improvement of the photovoltaic cell 10 can be achieved.

Moreover, it is preferable that the width A of the divided portion is 30 μm or more and 5000 μm or less. Here, the width A of the divided portion is, for example, 30, 300, 1000, 2000, 3000, 4000, 5000 μm. The width A may be within the range of any two values exemplified here. When the width A of the divided portion is less than 30 μm, there is a problem that the finger electrode 12 is not reliably divided, and when it exceeds 5000 μm, the light receiving surface area cannot be sufficiently secured and the conversion efficiency is lowered, which is not preferable. . From the viewpoint of maintaining high conversion efficiency, it is more preferably 30 μm or more and 2000 μm or less.

Moreover, it is preferable that the sum of the lengths of the finger electrode pieces 12a in the light receiving surface electrode unit 16a and the sum of the lengths of the finger electrode pieces 12a in the light receiving surface electrode unit 16b are substantially the same. With such a structure, the load applied to the surface bus bar electrode 11a becomes more uniform, the deterioration rate of the surface bus bar electrode 11a becomes more uniform, and the life of the solar battery cell 10 can be extended.

In another embodiment of the present invention, among the plurality of finger electrode segments 12a on both sides of the divided portion, the plurality of finger electrode segments 12a on the same side are electrically connected to each other. It is preferable to further have a line 14. The width of the finger electrode connecting line 14 is 20 μm or more and 200 μm or less, for example, 20, 50, 100, or 200 μm. The width may be within the range of any two values exemplified here. When the width of the finger electrode connecting line 14 is less than 20 μm, the function as the connecting line cannot be sufficiently exhibited. When the width exceeds 200 μm, the light receiving surface area cannot be sufficiently secured and the conversion efficiency is lowered. In the solar cell industry, the presence or absence of defects in the finger electrode 12 (for example, the division of the finger electrode) is usually inspected using the EL method (Electro-Luminescence), but the solar cell 10 of the present invention is connected to the finger electrode. Since it has the line 14, it becomes possible to reduce the influence by the defect of the finger electrode 12, and it becomes possible to raise the conversion efficiency of the photovoltaic cell 10. FIG.

The finger electrode connection line 14 is not particularly limited as long as it is a form that electrically connects the plurality of finger electrode pieces 12a to each other. In the example shown in FIG. 4, the finger electrode connection line 14 is a straight line arranged vertically at the end of the finger electrode piece 12 a, but in addition to such a shape, for example, the finger electrode connection line 14 is connected to the finger electrode connection line 14. It is also possible to provide it at the center of the finger electrode segment 12a or at a location away from the end by a certain distance. Moreover, you may arrange | position so that it may be substantially perpendicular | vertical to the location finger electrode fragment 12a, and can also specifically have an angle of 80 to 100 degree | times with respect to the finger electrode fragment 12a. Of course, when the ends of the finger electrode segments 12a do not coincide, the finger electrode connection line 14 may be a waveform or a zigzag line. Of course, the finger electrode connection line 14 may be provided so as to be connected to a part of the finger electrode segments 12a among the plurality of finger electrode segments 12a.

As described above, when the finger electrode segment 12a is connected by the finger electrode connecting line 14 and a defect (see FIG. 4) occurs in the finger electrode segment 12a, the defect of the defect is viewed from the surface bus bar electrode 11a. Further, since the current from the finger electrode segment 12a on the far side flows through the finger electrode connecting line 14 to the adjacent finger electrode segment 12a, the current can be collected without waste, and the conversion efficiency can be further increased. It becomes possible. Moreover, according to such a structure, it leads also to the improvement of the design property of the photovoltaic cell 10 besides a functional part.

Moreover, in another embodiment of this invention, the photovoltaic cell 10 of this invention has the frame line 15 which electrically connects the said several finger electrode 12 mutually in each of the both ends of the several finger electrode 12. FIG. The frame line 15 can also be provided at a position away from the end of the finger electrode 12 by a certain distance.

Thus, in the photovoltaic cell 10 of the present invention, the plurality of finger electrodes 12 are electrically connected to each other by the frame line 15 at each of the both ends of the plurality of finger electrodes 12. When the end near the edge is connected by the frame line 15 and a defect occurs in the finger electrode 12 on the left side of the leftmost surface busbar electrode 11a or on the right side of the rightmost surface busbar electrode 11a, the defect Further, the current from the finger electrode 12 on the edge side of the current flows through the frame line 15 to the adjacent finger electrode 12, so that current can be collected without waste and the conversion efficiency can be further increased. Become.

A method for producing the finger electrode 12 is not particularly limited. For example, the finger electrode 12 can be produced by printing and baking using a paste mainly composed of silver. Since one solar cell generates a small electrical output, it is necessary to connect a large number of solar cells in series and parallel so that a practical electrical output can be taken out. Here, since an expensive material is used as the material for the finger electrodes, each finger electrode 12 is divided into a plurality of finger electrode segments 12a, thereby reducing the amount of silver material used, leading to a cost town.

In a preferred embodiment of the present invention, each surface bus bar electrode 11a is preferably located on the center line of the plurality of finger electrode segments 12a. With this structure, the surface bus bar electrode 11a can collect the current from the finger electrode segment 12a more efficiently.

Hereinafter, although the preferable manufacturing method of the photovoltaic cell 10 is demonstrated in detail, it is not limited to such a manufacturing method.

FIG. 3 is a flowchart showing a method for manufacturing a solar battery cell according to the present invention. As shown in FIG. 3, first, a flat p-type silicon substrate 1 having a size of 156 mm × 156 mm is manufactured using a casting method.

Next, the sufficiently cleaned p-type silicon substrate 1 is placed in a diffusion furnace and heated using phosphorus oxychloride to diffuse phosphorus atoms on the surface of the p-type silicon substrate 1 and n The mold diffusion layer 2 is formed.

Thereafter, an antireflection film 3 made of a silicon nitride film is formed on the surface side of the p-type silicon substrate 1 by plasma CVD.

Thereafter, the finger electrode 12 and the surface bus bar electrode 11 a are formed on the light receiving surface of the semiconductor substrate 13. Specifically, the semiconductor substrate 13 is installed in a screen printer, and a silver paste is applied as the finger electrode 12 and the surface bus bar electrode 11a. Here, a plurality of finger electrodes 12 extending in parallel to each other are formed on the light receiving surface side of the semiconductor substrate so that each finger electrode segment 12a has a length of 75 mm. As the surface bus bar electrode 11a, the width is set to 2 mm, and two surface bus bar electrodes 11a are formed.

Thereafter, the back bus bar electrode 11 b is formed on the non-light receiving surface of the semiconductor substrate 13. The back bus bar electrode 11b can also be manufactured by applying a silver paste. Also, here, the two backside bus bar electrodes 11b are formed so that each width is 2 mm.

Thereafter, an aluminum paste is screen printed on the entire back surface of the p-type silicon substrate 1 to form the BSF layer 4.

The width A of the divided part between the finger electrodes was as shown in Table 1 below.

Based on the parameters in Table 1, the conversion efficiency and the presence / absence of connection in the divided portion were measured for the solar cells produced by the above production method.

As shown in Table 1, when the width A of the divided part is 30 μm or more and 5000 μm or less, the conversion efficiency is 16.80% or more, and the difference from the desired conversion efficiency of 17.00% is within the allowable range. That is, it was 0.2% or less. Moreover, the finger electrodes are also reliably separated. In particular, when the width of the divided portion was 30 μm or more and 2000 μm or less, the conversion efficiency was 17.00% in all cases.

Also, when the width A of the divided portion is 6000 μm, the conversion efficiency falls to 16.70%, and the difference from the desired conversion efficiency of 17.00% exceeds the allowable range, and the conversion efficiency is too low. There was an undesirable result.

Moreover, when the width A of the divided part is 20 μm, the divided part is connected, and there is a problem that the divided part is not reliably divided. In this case, each surface bus bar electrode 11a cannot collect current equally, and the deterioration rate of the surface bus bar electrode 11a is different, so that there is a problem that the life of the solar battery cell is shortened.

Next, after the defect was randomly attached to the finger electrode 12, the conversion efficiency when the finger electrode connection line 14 was provided and when the finger electrode connection line 14 was not provided was compared. The results are shown in Table 2 below.

As shown in Table 2 above, when the finger electrode 12 is defective, the conversion efficiency when the finger electrode connecting line 14 is not provided is 16.70%, whereas the finger electrode connecting line 14 is provided. The conversion efficiency was at least 16.90%, and all of them were almost unaffected by the defect of the finger electrode 12, and high conversion efficiency could be maintained. The reason is that when the finger electrode segment 12a has a defect, the current from the finger electrode segment 12a farther from the defect as viewed from the surface bus bar electrode 11a is adjacent via the finger electrode connecting line 14. This is because the current flows through the finger electrode pieces 12a, so that current can be collected without waste and high conversion efficiency is realized.

Embodiment of this invention is not limited only to the above-mentioned example, A various change can be added in the range which does not deviate from the summary of this invention.

1: p-type silicon substrate 2: n-type diffusion layer 3: antireflection film 4: BSF layer 10: solar cell 5a, 11a: front surface bus bar electrode 5b, 12: finger electrode 12a: finger electrode fragment 11b: back surface bus bar electrode 13 : Semiconductor substrate 14: Finger electrode connecting line 15: Frame lines 16a and 16b: Light-receiving surface electrode unit A: Width of divided part

Claims (7)

A semiconductor substrate;
A plurality of finger electrodes extending parallel to each other on the light receiving surface side of the semiconductor substrate;
Two or more surface bus bar electrodes electrically connected to each of the plurality of finger electrodes and formed to intersect with the finger electrodes;
Two or more back surface bus bar electrodes formed directly below each front surface bus bar electrode across the semiconductor substrate on the non-light-receiving surface side of the semiconductor substrate,
Each of the plurality of finger electrodes is divided into a plurality of finger electrode segments between the adjacent surface bus bar electrodes, and two or more sets of light receiving surface electrode units configured by the respective surface bus bar electrodes and the finger electrode segments. Further comprising
The width of the divided part is 30 μm or more and 5000 μm or less,
The finger electrode connecting line has a width of 20 μm or more and 200 μm or less,
The sum of the lengths of the finger electrode pieces in each of the light receiving surface electrode units is substantially the same,
A solar battery cell characterized by that. 2. The solar cell according to claim 1, wherein the divided portion has a width of 30 μm or more and 2000 μm or less. The finger electrode connecting line that further electrically connects the plurality of finger electrode segments on the same side among the plurality of finger electrode segments on both sides of the divided portion. The solar cell according to claim 2. The solar cell according to any one of claims 1 to 3, further comprising a frame line that electrically connects the plurality of finger electrodes to each other at both ends of the plurality of finger electrodes. The solar cell according to any one of claims 1 to 4, wherein the finger electrodes are provided in a range of 70 to 140 on the semiconductor substrate. The solar cell according to any one of claims 1 to 4, wherein the finger electrode has a width of 20 µm or more and 90 µm or less. The solar cell according to any one of claims 1 to 4, wherein the surface bus bar electrode has a width of 1 mm to 2 mm.