TW201906186A - Solar battery cell and solar battery module - Google Patents

Abstract

The present invention comprises: a semiconductor substrate that has a p-n junction; a light-receiving surface bus electrode (12B) that is provided extending in a first direction on a light-receiving surface side of the semiconductor substrate; and a plurality of back surface connection electrodes that are provided distributed along the first direction on a back surface side of the semiconductor substrate, said back surface side facing toward the opposite side from the light-receiving surface. A plurality of through holes (60) that pass through in a thickness direction of the light-receiving surface bus electrode are provided in the light-receiving surface bus electrode (12B) along the first direction, and the back surface connection electrodes are positioned in locations facing a region of the light-receiving surface bus electrode (12B) in a thickness direction of the semiconductor substrate, said region excluding the plurality of through holes (60).

Description

 Solar battery unit and solar battery module  

The present invention relates to a solar battery unit that constitutes a solar battery module by wire bonding, and a solar battery module using the solar battery unit.

When the solar cell unit is modularized, a plurality of solar cell units are electrically connected in series, and a lead wire made of a rectangular copper wire is soldered to each solar cell unit under the target of taking out the electric output. The lead wire is usually shrunk directly after cooling from a high temperature state to a normal temperature after soldering. Thus, in the solar cell after soldering, the lead is bent due to shrinkage of the lead. The bending of the solar cell unit causes damage to the solar cell unit.

On the light-receiving surface and the back surface of the solar cell, a gate electrode for taking out electricity generated in the solar cell and a bus bar electrode for collecting electricity from all the gate electrodes are disposed. In order to increase the power generation area of the solar cell, the gate electrode is improved in thinning and majority quantization. On the other hand, the bus bar electrode has difficulty in thinning due to the relationship between the bonding strength of the solar cell and the lead wire and the arrangement accuracy. Further, since the heat treatment at the time of forming the gate electrode and the bus bar electrode causes damage to the power generation layer, the power generation efficiency of the solar cell unit is lowered, and high-priced silver must be used in the electrode material plus the area as much as possible.

According to Patent Document 1, a bus bar portion formed on a main surface of a semiconductor substrate has a slit portion in which a plurality of slits are arranged along a longitudinal direction portion of the bus bar portion, and the electrode paste is printed by a screen printing method. . According to the technique of Patent Document 1, while maintaining the good bonding strength between the bus bar electrode and the lead wire, the area of the bus bar electrode can be reduced, but the bending of the solar cell unit generated after the wire bonding can not be solved.

On the other hand, in the back surface of the solar battery cell, the bus bar electrode is required to be bonded to the back surface wire in the same manner as the light receiving surface. However, since a large amount of electrode material is required in the bus bar electrode arranged in a straight line, the arrangement is not linear. It is an island-shaped joint electrode.

 [advance technical documents]    [Patent Document]  

[Patent Document 1] Patent No. 4284368

However, in recent years, the thickness of the ruthenium substrate used in the solar cell unit has been decreasing year by year, and it is expected to continue to decrease in the future. Since the bending due to the difference in thermal expansion coefficient between the lead and the solar cell unit occurs in the manufacturing process of the solar cell module, it is necessary to reduce the bending in the module manufacturing step. Thus, the occurrence of this bending is more pronounced as the thickness of the ruthenium substrate is thinner.

The present invention has been made in view of the above, and an object thereof is to provide a solar battery cell capable of suppressing bending of a solar battery cell caused by wire bonding of a solar battery cell.

In order to solve the above problems, the present invention includes a semiconductor substrate having a pn junction, a light-receiving surface bus bar electrode extending in a first direction on a light-receiving surface side of the semiconductor substrate, and a plurality of back-side connecting electrodes facing the semiconductor The back side of the substrate on the opposite side to the light receiving surface is disposed to be dispersed along the first direction. The light-receiving surface bus bar electrode is provided with a plurality of through holes penetrating in the thickness direction of the light-receiving surface bus bar electrode in the first direction, and the back surface is connected to the electrode, and is disposed in the thickness direction of the semiconductor substrate in the thickness direction of the light-receiving surface bus bar electrode. The position of the area outside the through hole.

According to the solar cell of the present invention, the effect of suppressing the bending of the solar cell unit caused by the wire bonding of the solar cell unit can be suppressed.

1, 11‧‧‧ semiconductor substrate

2‧‧‧n type impurity diffusion layer

3‧‧‧Anti-reflection film

4‧‧‧BSF layer (back surface electric field layer)

10, 110, 210‧‧‧ solar battery unit

11A‧‧‧Glossy surface

11B‧‧‧Back

12, 112, 212‧‧‧ light-receiving electrodes

12a‧‧‧ Silver electrode paste

12B, 112B, 212B‧‧‧ light-receiving busbar electrodes

12Ba‧‧‧Side side of the light-receiving busbar electrode

12G‧‧‧Glossy gate electrode

13, 113, 213‧‧‧ back electrode

13A‧‧‧Back collector electrode

13B, 113B, 213B‧‧‧ back connection electrode

1131~1138‧‧‧ back connection electrode

13a‧‧‧Aluminum electrode paste

13b‧‧‧ Silver electrode paste

20‧‧‧ lead

20a‧‧‧Bend

20b‧‧‧The side of the lead in the lateral direction

25‧‧‧ horizontal lead

26‧‧‧Output leads

31‧‧‧Glossy Surface Protection Department

32‧‧‧Back Protection Department

33‧‧‧Lighted side sealing material

34‧‧‧Back side sealing material

40‧‧‧Frame

50‧‧‧Sun battery string

60‧‧‧through holes

61, 611~618‧‧‧1st area

62‧‧‧2nd area

63‧‧‧Connecting Department

63a‧‧‧Side side of the joint

70‧‧‧Solar battery array

100‧‧‧Solar battery module

101‧‧‧End

102‧‧‧The other end

A1~A8‧‧‧1st area length

B1~B9‧‧‧Distance

C1~C8‧‧‧ back connection electrode length

D1~D9‧‧‧Distance

[Fig. 1] is a perspective view of a solar battery module according to a first embodiment of the present invention as seen from the light receiving surface side. [Fig. 2] is an exploded perspective view of the solar battery module according to the first embodiment of the present invention as seen from the light receiving surface side. [Fig. 3] is a cross-sectional view of a main portion of a solar cell module according to a first embodiment of the present invention; [Fig. 4] is a perspective view of a solar cell array according to the first embodiment of the present invention as seen from the back side; [5th] Fig. 6 is a perspective view of a solar battery string according to a first embodiment of the present invention as seen from the side of the light receiving surface; [Fig. 6] is a perspective view of the solar battery string according to the first embodiment of the present invention as seen from the back side; [Fig. 7] A plan view of the solar battery cell according to the first embodiment of the present invention as seen from the side of the light receiving surface; [Fig. 8] is a plan view of the solar battery cell according to the first embodiment of the present invention as seen from the back side facing the side opposite to the light receiving surface side; Fig. 9 is a cross-sectional view showing a configuration of a solar battery cell according to a first embodiment of the present invention, which is a cross-sectional view of a main portion taken along line IX-IX in Fig. 7; [Fig. 10] shows the first aspect of the present invention. Embodiment of the solar cell unit The cross-sectional view of the main portion in the XX line in Fig. 7; [Fig. 11] is a plan view showing the shape of the light-receiving surface bus bar electrode of the solar cell unit according to the first embodiment of the present invention; Fig. 1 is a plan view showing a state in which a lead is welded to a light-receiving surface bus bar electrode of a solar battery cell according to the first embodiment of the present invention; and Fig. 13 is a cross-sectional view showing a configuration of a solar battery cell according to the first embodiment of the present invention. FIG. 14 is a cross-sectional view showing a main portion of the solar cell unit according to the first embodiment of the present invention, and FIG. 14 is a cross-sectional view showing the configuration of the solar cell according to the first embodiment of the present invention, which is the XIV-XIV in FIG. The cross-sectional view of the main part of the line; [Fig. 15] is a procedure for explaining the manufacturing steps of the solar cell according to the first embodiment of the present invention; [Fig. 16] shows the manufacture of the solar cell of the first embodiment of the present invention. [section 17] is a cross-sectional view showing a main part of a manufacturing process of a solar battery cell according to a first embodiment of the present invention; and [18] is a solar battery cell according to a first embodiment of the present invention. of [Fig. 19] is a cross-sectional view showing a main part of a manufacturing process of a solar cell according to a first embodiment of the present invention; [Fig. 20] shows a solar cell according to a first embodiment of the present invention. A cross-sectional view of a main part of a manufacturing process of a unit; [21] is a cross-sectional view showing a main part of a manufacturing process of a solar cell according to a first embodiment of the present invention; [Fig. 22] shows a first embodiment of the present invention. A cross-sectional view of a main part of a manufacturing process of a solar cell; [Fig. 23] is a program for explaining a method of manufacturing a solar cell module according to the first embodiment of the present invention; [Fig. 24] is a view of the present invention as seen from the side of a light receiving surface A plan view of a solar battery cell according to a second embodiment of the present invention; [Fig. 25] is a plan view of a solar battery cell according to a second embodiment of the present invention as seen from the back side facing the light-receiving surface side; [Fig. 26] shows the present invention A cross-sectional view of a configuration of a solar cell module according to a second embodiment of the present invention; [FIG. 27] FIG. 27 is a view showing a configuration condition of a light-receiving surface electrode of a solar cell according to a second embodiment of the present invention. [FIG. 28] FIG. 29 is a cross-sectional view showing a configuration of a solar cell of a third embodiment of the present invention; [30th] FIG. 4 is a view showing a configuration condition of a light-receiving surface electrode of a solar battery cell according to a third embodiment of the present invention; and FIG. 31 is a view showing a configuration condition of a back surface connection electrode of a solar battery cell according to a third embodiment of the present invention.

Hereinafter, the solar battery cell and the solar battery module according to the embodiment of the present invention will be described in detail based on the drawings. Further, the invention is not limited by this embodiment.

 [First Embodiment]  

Fig. 1 is a perspective view of the solar battery module 100 according to the first embodiment of the present invention as seen from the side of the light receiving surface. Fig. 2 is an exploded perspective view of the solar battery module 100 according to the first embodiment of the present invention as seen from the side of the light receiving surface. Fig. 3 is a cross-sectional view showing the essential part of a solar battery module 100 according to the first embodiment of the present invention. In the solar battery module 100 of the first embodiment, as shown in FIGS. 1 to 3, the light-receiving surface side of the solar cell array 70 is covered by the light-receiving surface side sealing material 33 and the light-receiving surface protection portion 31, and faces the solar cell array 70. The back side of the opposite side of the light receiving surface is covered by the back side sealing material 34 and the back surface protecting portion 32, and the periphery of the outer peripheral edge portion is surrounded by the reinforcing frame 40.

Fig. 4 is a perspective view of the solar cell array 70 according to the first embodiment of the present invention as seen from the back side. Fig. 5 is a perspective view of the solar battery string 50 according to the first embodiment of the present invention as seen from the side of the light receiving surface. Fig. 6 is a perspective view of the solar battery string 50 according to the first embodiment of the present invention as seen from the back side.

As shown in FIG. 4, the solar cell array 70 is configured to electrically and mechanically connect a plurality of solar cell strings 50 in series and in parallel with the horizontal lead 25 and the output lead 26.

Further, as shown in FIGS. 3 to 6, the solar battery string 50 is configured such that the lead wires 20 are electrically and mechanically connected in series to each other to form a plurality of solar battery cells 10 having a quadrangular shape. The plurality of solar battery cells 10, as shown in Figs. 3 to 6, are connected in series by the lead wires 20 in the X direction in the drawing in the first direction. The first direction is a connection direction of a plurality of solar battery cells 10 connected by leads 20.

In the solar battery string 50, the electrode formed on the light-receiving surface side of the first main surface of one of the adjacent two solar battery cells 10 and the other solar battery of the adjacent two solar battery cells 10 The electrodes formed on the back side of the second main surface of the unit 10 are alternately connected by a lead wire 20. Then, one end side of the lead wire 20 is welded to the back surface connection electrode 13B formed on the back surface side of the solar battery cell 10 to be described later, and the other end side is welded to the light-receiving surface bus bar electrode 12B formed on the light-receiving surface side of the adjacent solar battery cell 10. In other words, the lead wire 20 connected to the light-receiving surface bus bar electrode 12B formed on the light-receiving surface side of the solar battery cell 10 is connected to the back surface connecting electrode 13B formed on the back side of the adjacent solar battery cell 10, and a plurality of solar battery cells are connected in series. 10.

Fig. 7 is a plan view showing the solar battery cell 10 of the first embodiment of the present invention as seen from the side of the light receiving surface. Fig. 8 is a plan view showing the solar battery cell 10 according to the first embodiment of the present invention as seen from the back side facing the side opposite to the light receiving surface side. Fig. 9 is a cross-sectional view showing the configuration of a solar cell unit 10 according to the first embodiment of the present invention, and is a cross-sectional view of a principal part taken along line IX-IX in Fig. 7. Fig. 10 is a cross-sectional view showing the configuration of a solar cell unit 10 according to the first embodiment of the present invention, and is a cross-sectional view of a principal part taken along line X-X in Fig. 7. Further, in the ninth and tenth drawings, the lead wires 20 connected to the solar battery cells 10 are simultaneously displayed.

The solar cell unit 10, including the semiconductor substrate 11, exhibits a quadrangular shape in which an impurity diffusion layer is formed to constitute a pn junction. In the solar cell unit 10, on the light-receiving surface side of the surface of the semiconductor substrate 1 composed of the p-type ytterbium of the first conductivity type, an n-type impurity diffusion layer 2 in which an impurity diffusion layer of an n-type impurity is diffused and diffused by phosphorus is formed. The n-type impurity diffusion layer 2 is formed on the light-receiving surface 11A side of the semiconductor substrate 11. The outer shape of the semiconductor substrate 11 has a square shape in the surface direction of the semiconductor substrate 11, that is, a rectangular shape.

In the solar cell unit 10, on the light-receiving surface 11A side of the semiconductor substrate, which is the first main surface of the semiconductor substrate 11, in order to increase the light collection ratio of the light, the uneven shape is formed by texture etching. That is, on the surface of the semiconductor substrate 11, minute irregularities are formed as a texture structure. The fine unevenness increases the area of the light-receiving surface 11A that absorbs light from the outside, suppresses the reflectance in the light-receiving surface 11A, and becomes a structure that turns off light. Further, in the figures 9 and 10, for the sake of convenience, the illustration of the fine unevenness is omitted. In the solar cell unit 10, an anti-reflection film 3 made of a nitrogen-deposited film is formed on the light-receiving surface 11A side of the semiconductor substrate, which is the first main surface of the semiconductor substrate 11.

In the semiconductor substrate 1, a p-type single crystal germanium substrate or a p-type polycrystalline germanium substrate can be used. Further, the semiconductor substrate 1 is not limited thereto, and an n-type single crystal germanium substrate, an n-type polycrystalline germanium substrate, or another germanium-based substrate may be used. Further, in the anti-reflection film 3, an oxynitride film may be used.

In the solar cell unit 10, the light-receiving surface electrode 12 is formed on the light-receiving surface 11A side of the semiconductor substrate, and the back surface electrode 13 is formed on the second main surface of the semiconductor substrate 11, that is, the back surface 11B side of the semiconductor substrate.

On the light-receiving surface side of the semiconductor substrate 1, the above-described light-receiving surface electrode 12 is electrically connected to the n-type impurity diffusion layer 2 through the anti-reflection film 3. As the light-receiving surface electrode 12, a plurality of elongated elongated light-receiving surface gate electrodes 12G are arranged in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. The light-receiving surface gate electrode 12G is an electrode for collecting photocurrent generated by the solar cell unit 10 from the light-receiving surface 11A side of the semiconductor substrate 11. The light-receiving surface gate electrode 12G is electrically connected to the n-type impurity diffusion layer 2 at the bottom surface portion. The light-receiving surface gate electrode 12G is a paste electrode formed by applying a conductive paste having metal particles and firing it in a desired range.

In addition, the light-receiving surface bus bar electrode 12B that is electrically connected to the light-receiving surface gate electrode 12G is disposed to be orthogonal to the light-receiving surface gate electrode 12G in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. As shown in FIG. 7, the light-receiving surface bus bar electrode 12B is provided in four rows along the substantially full length of the solar battery cell 10 in the first direction along the connection direction of the solar battery cells 10. In other words, the longitudinal direction of the light-receiving surface bus bar electrode 12B is the same direction as the first direction, and the connection direction of the plurality of solar battery cells 10 connected by the lead wires 20 is obtained. Further, in the direction in which the light-receiving surface bus bar electrodes 12B are arranged, the same direction as the second direction orthogonal to the first direction is formed in the surface of the semiconductor substrate 11. The light-receiving surface bus electrode 12B is provided to be connected to all of the light-receiving surface gate electrodes 12G. The light-receiving surface bus bar electrode 12B electrically connects the n-type impurity diffusion layer 2 to the bottom surface portion. Further, for convenience, in the first, second, fourth, and fifth drawings, the case where two rows of light-receiving surface bus electrodes 12B are provided is shown.

The light-receiving surface bus electrode 12B is provided with an optical current for collecting the light-receiving surface gate electrode 12G and an electrode for electrically bonding with the lead wire 20. The light-receiving surface bus bar electrode 12B is a paste electrode formed by applying a conductive paste having metal particles and firing it in a desired range. When the solar cell module 100 is manufactured using the solar battery cell 10, the lead wire 20 is soldered to the light-receiving surface bus electrode 12B as shown in Figs. Further, in the ninth and tenth drawings, only the light-receiving surface bus bar electrode 12B of the light-receiving surface electrode 12 is displayed.

Fig. 11 is a plan view showing the shape of the light-receiving surface bus bar electrode 12B of the solar cell unit 10 according to the first embodiment of the present invention. As shown in FIGS. 7 and 11 , the inside of the light-receiving surface bus bar electrode 12B penetrates the plurality of through holes 60 of the light-receiving surface bus bar electrode 12B in the thickness direction, and is in the in-plane direction of the solar cell 10 , that is, the surface of the semiconductor substrate 11 . The inner direction is arranged to be spaced apart from the stepping stone shape along the first direction. In the seventh drawing, for example, seven through-holes 60 are provided in the light-receiving surface bus bar electrode 12B along the first direction.

In other words, the light-receiving surface bus bar electrode 12B includes a plurality of first regions 61 in which the through holes 60 are not provided and a plurality of second regions 62 in which the through holes 60 are provided in the first direction. The plurality of first regions 61 and the plurality of second regions 62 are alternately arranged in the first direction of the light-receiving surface bus bar electrode 12B in the extending direction. In the second region 62, the connection portion 63 provided in the outer edge region in the lateral direction of the light-receiving surface bus bar electrode 12B is connected between the adjacent first regions 61 in the extending direction of the light-receiving surface bus bar electrode 12B. Therefore, all of the first region 61 and the second region 62 of one of the light-receiving surface bus electrodes 12B are electrically connected.

Further, the lead wire 20 is soldered to the light-receiving surface bus bar electrode 12B mainly by soldering the first region 61 and the lead wire 20. Therefore, the welding area of the light-receiving surface bus bar electrode 12B and the lead wire 20 approximates the welding area of the first region 61 and the lead wire 20.

Since a plurality of through holes 60 are provided in the light-receiving surface bus bar electrode 12B, the amount of electrode material used in the light-receiving surface bus bar electrode 12B can be reduced, and the manufacturing cost of the solar cell unit 10 can be reduced.

Moreover, the size and position of the through hole 60 may be a size and a position of a back surface connection electrode 13B to be described later. The size and position of the back surface connection electrode 13B are determined in consideration of the characteristics of the solar battery cell 10.

In addition, the resistance of the light-receiving surface bus bar electrode 12B is increased by providing a plurality of through-holes 60 in the light-receiving surface bus bar electrode 12B, and can be suppressed by increasing the height of the light-receiving surface bus bar electrode 12B.

Further, as shown in FIG. 11, the light-receiving surface bus bar electrode 12B has the same width in the longitudinal direction, and the width in the first region 61 is equal to the width in the second region 62, and both ends in the second direction. A straight line parallel to the first direction is formed. The second direction corresponds to the Y direction in Fig. 11. Then, when the solar cell module 100 is manufactured for the electrode connection lead 20 of the solar cell unit 10, the lead wire 20 having the same width as the light-receiving surface bus bar electrode 12B is overlapped with the position of the light-receiving surface bus bar electrode 12B in the second direction. The light-receiving surface bus bar electrode 12B is welded to the light-receiving surface bus bar electrode 12B.

Fig. 12 is a plan view showing a state in which the lead wires 20 are welded to the light-receiving surface bus bar electrode 12B of the solar battery cell 10 according to the first embodiment of the present invention. Fig. 13 is a cross-sectional view showing the configuration of a solar cell unit 10 according to the first embodiment of the present invention, and is a cross-sectional view of a principal part taken along line XIII-XIII in Fig. 12. Fig. 14 is a cross-sectional view showing the configuration of a solar cell unit 10 according to the first embodiment of the present invention, and is a cross-sectional view of a main portion of the XIV-XIV line in Fig. 12.

As shown in Figs. 13 and 14, the lead wire 20 is parallel to the light-receiving surface bus bar electrode 12B, and is disposed on the light-receiving surface bus bar electrode 12B at a position overlapping the light-receiving surface bus bar electrode 12B in the lateral direction of the lead wire 20. Soldered to the upper surface of the light-receiving surface bus bar electrode 12B. In other words, in the second surface, the lead surface of the light-receiving surface bus bar electrode 12B is soldered to the side surface 12b of the light-receiving surface bus bar electrode in the lateral direction in the lateral direction of the side surface 20b. The longitudinal direction of the lead 20 in a state of being welded to the light-receiving surface bus bar electrode 12B is the same as the longitudinal direction of the light-receiving surface bus bar electrode 12B, and is the same direction as the above-described first direction, that is, the X direction. The lateral direction of the lead 20 in a state of being welded to the light-receiving surface bus bar electrode 12B is the same as the width of the light-receiving surface bus bar electrode 12B, and is in the same direction as the above-described second direction, that is, the Y direction.

As shown in Fig. 12, the lead wires 20 have the same width in the longitudinal direction and are formed to have the same width as the width of the light-receiving surface bus bar electrode 12B. Therefore, as shown in Fig. 13, in the second region 62 in which the plurality of through holes 60 are provided, the width of the lead 20 and the width of the second region 62, that is, the side of the outer side of the two connecting portions in the second direction The length between 63a is the same size. The side surface 63a of the outer side of the connecting portion corresponds to the side surface 12Ba of the light-receiving surface bus bar electrode in the second region 62. As shown in Fig. 14, in the first region 61 in which the plurality of through holes 60 are not provided, the width of the lead 20 is the same as the length of the first region 61, that is, the length of the first region 61 in the second direction.

In the second region 62 in which the plurality of through holes 60 are provided, the lead wire 20 is soldered to the light receiving surface bus bar electrode 12B, and is soldered to the lead wire 20 via the connection portion 63 provided in the outer edge region in the lateral direction of the light receiving surface bus bar electrode 12B. Both ends of the lead 20 in the lateral direction are performed.

The width of the light-receiving surface bus bar electrode 12B is 0.6 mm (mm) or more and 1.2 mm or less. The width of the light-receiving surface gate electrode 12G is 30 μm (micrometers) or more and 80 μm (micrometers) or less. The width of the connecting portion 63 is 60 μm (micrometers) or more and 160 μm (micrometers) or less. The width of the connecting portion 63 is 1/15 or more and 1/5 or less in width with respect to the width of the light-receiving surface bus bar electrode 12B. When the width of the light-receiving surface bus bar electrode 12B is in the above-described range, the connection portion is reduced in consideration of the decrease in the amount of use of the electrode material used in the light-receiving surface bus bar electrode 12B and the increase in the resistance of the light-receiving surface bus bar electrode 12B in which the through-hole 60 is provided. The width of 63 is preferably about 1/10 of the width of the light-receiving surface bus bar electrode 12B.

When the width of the light-receiving surface gate electrode 12G is in the above range, the width of the connecting portion 63 is about twice as large as the width of the light-receiving surface gate electrode 12G. When the amount of use of the electrode material used in the light-receiving surface bus electrode 12B is lowered and the electric resistance of the light-receiving surface bus bar electrode 12B in which the through-hole 60 is provided is increased, the width of the connecting portion 63 is also based on the light-receiving surface bus bar electrode 12B. The height is preferably a width which is about twice the width of the glossy gate electrode 12G.

When the width of the light-receiving surface gate electrode 12G is thinned, how much the width of the thinned light-receiving surface-gate electrode 12G increases, and the number of light-receiving surface-gate electrodes 12G increases, and the amount of received light and the electrode resistance loss are in the same state, and the carrier arrives. Since the distance passing through the n-type impurity diffusion layer 2 is shortened by the light-emitting surface gate electrode 12G, the resistance loss in the n-type impurity diffusion layer 2 is reduced. Therefore, the thinning of the width of the light-receiving surface gate electrode 12G is desirable from the viewpoint of resistance loss. However, the width of the light-receiving surface gate electrode 12G is selected in accordance with the manufacturing limit. In particular, when the light-receiving surface gate electrode 12G is formed by inexpensive screen printing, the lower limit width of the light-receiving surface gate electrode 12G which can be formed in the thinning is limited to 30 μm (micrometer) or more and 100 μm (micrometer) or less.

The width of the connecting portion 63 is also preferably thinned in view of the decrease in the amount of use of the electrode material. However, the lower limit width is selected in accordance with manufacturing constraints and characteristics limitations of the solar cell unit 10. The light-receiving surface gate electrode 12G and the connecting portion 63 and the light-receiving surface bus bar electrode 12B are simultaneously printed by screen printing using one printing mask. Therefore, the height of the light-receiving surface gate electrode 12G printed by the screen printing, the height of the connecting portion 63, and the height of the light-receiving surface bus bar electrode 12B are the same height. When the height of the light-receiving surface gate electrode 12G and the height of the connection portion 63 are the same, the current flowing into the connection portion 63, that is, the components of the light-receiving surface gate electrode 12G of two, three, five, or six, flows in, and is connected. The width of the portion 63 is preferably about twice as large as that of the light-receiving surface gate electrode 12G.

As described above, the light-receiving surface bus bar electrodes 12B are formed in parallel linear directions in the first direction at both end portions in the second direction. In other words, the light-receiving surface bus bar electrode 12B has a linear shape parallel to the first direction in the side surface 63a on the outer side of the two connecting portions opposed in the second direction. Then, when the solar cell module 100 is manufactured for the electrode connection lead 20 of the solar cell unit 10, the light-receiving surface bus bar electrode 12B is on the side surface 12Ba of the light-receiving surface bus bar electrode in the lateral direction in the second direction. The lead 20 is soldered in a state in which the side surface 20b of the lead in the lateral direction is overlapped. In other words, the position of the side surface 12Ba of the light-receiving surface bus bar electrode and the position of the side surface 20b in the lateral direction of the lead wire are located at the same position in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11.

Therefore, in a state where the lead wire 20 is welded to the light-receiving surface bus bar electrode 12B, the connecting portion 63 does not protrude further outward than the first region 61. In other words, in a state in which the lead wire 20 is soldered to the light-receiving surface bus bar electrode 12B, the connection portion 63 is included in the lead wire 20 in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11.

Therefore, in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11, the solar battery cell 10 can prevent the solar battery cell 10 of the connection portion 63 from being exposed from the lead wire 20 without being welded to the lower surface of the lead wire 20 The amount of light received decreases. In other words, the light-receiving surface of the light-receiving surface bus bar electrode 12B exposed to the lead wire 20 on the light-receiving surface 11A of the semiconductor substrate 11 is reduced in light-receiving area, and the photoelectric conversion efficiency can be prevented from being lowered.

For example, when the connection portion 63 is protruded outward from the first region 61 in the second direction, the area of the connection portion 63 exposed from the lead wire 20 connected to the light-receiving surface bus bar electrode 12B is small, and the amount of light received by the solar battery cell 10 is large. How much will fall, which is the reason for the decline in photoelectric conversion efficiency.

Further, the light-receiving surface bus bar electrode 12B is formed in a linear shape parallel to the first direction at both end portions in the second direction, and the connection portion 63 is connected to the first direction at the shortest distance in the in-plane direction of the semiconductor substrate 11. The first adjacent region 61 in the middle. Therefore, the photocurrent accumulated in the light-receiving surface bus bar electrode 12B can suppress the electric resistance loss in the second region 62 which is caused by the connection portion 63 which is narrower than the width of the first region 61.

When the light-receiving surface gate electrode 12G and the lead 20 are welded, stress concentration at the time of soldering to the light-receiving surface gate electrode 12G is concentrated, and the light-receiving surface gate electrode 12G may be broken. In the solar cell unit 10, the connection portion 63 and the lead 20 are soldered in the second region 62, and the light-receiving surface gate electrode 12G and the lead 20 are not soldered. Therefore, the solar battery cell 10 can suppress the disconnection of the light-receiving surface gate electrode 12G due to the welding of the light-receiving surface gate electrode 12G and the lead wire 20.

Moreover, when the solar cell unit 10 is connected to the electrode of the solar cell unit 10 to form the solar cell module 100, the general lead 20 having the same width can be formed over the longitudinal direction without using the special shape of the solar cell unit 10. Lead 20.

The solar cell module 100 uses a general lead 20 having the same width throughout the longitudinal direction. When the lead wire 20 is welded to the solar battery cell 10, the position of the solar cell unit 10 and the lead 20 in the longitudinal direction of the light-receiving surface bus bar electrode 12B and the lead wire 20 is determined, that is, the position of the light-receiving surface bus bar electrode 12B and the lead wire 20. The decision became unnecessary. Therefore, in the solar battery module 100, at any position in the longitudinal direction of the light-receiving surface bus bar electrode 12B and the lead wire 20, since the light-receiving surface bus bar electrode 12B and the lead wire 20 can be welded, it is easy to manufacture.

On the other hand, as shown in FIGS. 6 and 8 on the back surface 11B side of the semiconductor substrate, a back surface collector electrode 13A containing aluminum (Al) and a plurality of dot back surface connection electrodes 13B containing silver (Ag) are formed. The back electrode 13 is formed. Further, aluminum is formed on the back surface of the semiconductor substrate 1 from the back surface electric field layer 13A which is a back surface electric field layer for increasing the open voltage and the short-circuit current, in the vicinity of the region in contact with the back surface collector electrode 13A in the surface layer of the back surface of the semiconductor substrate 1. The back surface electric field (BSF: Back Surface Filed) layer 4 of the p+ region where the surface layer is highly diffused.

The back surface collector electrode 13A covers the BSF layer 4 and an electrode provided to collect the photocurrent generated by the solar cell 10 from the back surface 11B side of the semiconductor substrate 11, and covers the entire back surface of the solar cell unit 10. The back collector electrode 13A is a paste electrode formed by applying a conductive paste of metal particles having an electrode material Al to a desired range and then firing.

Further, the back surface of the electrode 13B is connected, and the photocurrent collected by the back surface collector electrode 13A is taken out to the outside, and an electrode for bringing in contact with the external electrode is provided. That is, the back surface connection electrode 13B is provided with an electrode for bonding to the lead wire 20. The back surface connection electrode 13B is provided in the first direction along the connection direction of the solar cell unit 10, similarly to the light receiving surface bus bar electrode 12B. The back surface connection electrode 13B is a paste electrode formed by applying a conductive paste of metal particles having an electrode material Ag and firing it in a desired range.

The back surface connection electrode 13B sandwiches the semiconductor substrate 11 and is disposed at a position facing the light-receiving surface bus bar electrode 12B. Further, as shown in FIG. 8, the back surface connection electrode 13B is disposed in a row of stepping stones in a substantially uniform manner over the entire length of the solar cell unit 10 along the first direction of the solar cell unit 10, and is arranged in four rows. By forming the back surface connection electrode 13B in a stepping stone shape, the amount of silver used can be suppressed, and the manufacturing cost can be suppressed.

Then, as shown in FIGS. 9 and 10, the in-plane direction of the solar cell unit 10, that is, the in-plane direction of the semiconductor substrate 11, is located in the through-hole 60 in the light-receiving surface bus bar electrode 12B. Locations where the location is inconsistent. In other words, the first region 61 and the back surface connection electrode 13B of the light-receiving surface bus bar electrode 12B are disposed between the semiconductor substrate 11 in the thickness direction of the semiconductor substrate 11 with the semiconductor substrate 11 interposed therebetween. Therefore, the first region 61 and the back surface connection electrode 13B of the light-receiving surface bus bar electrode 12B are disposed at positions corresponding to the surface of the semiconductor substrate 11.

Therefore, in one solar battery cell 10, the lead 20 welded to the light-receiving surface bus bar electrode 12B on the light-receiving surface side and the lead wire 20 connected to the back surface connection electrode 13B on the back surface side are in the in-plane direction of the solar cell unit 10, that is, the semiconductor. In the in-plane direction of the substrate 11, the solar cell unit 10 is soldered at the same position. In other words, in one solar battery cell 10, the lead wire 20 welded to the light-receiving surface side of the solar battery cell 10 and the lead wire 20 soldered to the back surface side of the solar battery cell 10 are welded at positions opposed to each other in the thickness direction of the semiconductor substrate 11.

Therefore, in the in-plane direction of the solar battery cell 10, the area of the first region 61 of the light-receiving surface bus bar electrode 12B is substantially the same as the area of the back surface connection electrode 13B, and the welding area of the light-receiving surface bus bar electrode 12B and the lead wire 20 is The welding area of the back connection electrode 13B and the lead 20 is almost equal.

Therefore, in the solar battery cell 10 of the first embodiment, in order to form the plurality of solar battery cells 10, the connection portion of the lead wire 20 and the light-receiving surface bus bar electrode 12B when the lead wire 20 is welded to the solar battery cell 10, and the lead wire 20 are The internal stress generated in the connection portion of the back surface connection electrode 13B is almost offset.

When the lead wire 20 is connected to the electrode of the solar cell unit 10 to manufacture the solar cell module 100, as shown in Figs. 9 and 10, the soldering lead 20 is connected to the light-receiving surface bus bar electrode 12B and the back surface connecting electrode 13B. When the light-receiving surface bus electrode 12B does not have the through hole 60 and the back surface connection electrode 13B is dispersed and arranged in a stepping stone shape, the area of the light-receiving surface bus bar electrode 12B in the in-plane of the semiconductor substrate 11 and the in-plane back surface of the semiconductor substrate 11 The difference between the areas of the connection electrodes 13B becomes large. Therefore, the internal stress generated in the connection portion between the lead 20 and the light-receiving surface bus electrode 12B which is produced by the soldering of the lead 20 in the production of the solar cell module 100, and the internal stress generated in the connection portion between the lead 20 and the back-side connecting electrode 13B are caused. The difference between them becomes larger. In this case, the internal stress generated in the connection portion between the light-receiving surface side lead 20 of the solar cell unit 10 and the light-receiving surface bus bar electrode 12B and the connection portion between the back surface side lead 20 and the back surface connection electrode 13B of the solar cell unit 10 There is no balance between the internal stresses generated in the middle, and the difference in internal stress becomes the main cause of the bending of the solar cell unit 10.

As a result, a curve due to a difference in thermal expansion coefficient between the lead 20 made of metal and the turn of the semiconductor substrate 11 is generated. Generally, the coefficient of thermal expansion of the metal constituting the lead 20 is larger than the coefficient of thermal expansion of the crucible. Therefore, when the light-receiving surface bus electrode 12B does not have the through hole 60 and the back surface connection electrode 13B is dispersed and arranged in a stepping stone shape, that is, the area of the light-receiving surface bus bar electrode 12B in the surface of the semiconductor substrate 11 is larger than the surface of the semiconductor substrate 11. When the area of the back surface connection electrode 13B is large, the solar cell unit 10 is bent toward the back side after soldering.

On the other hand, in the solar battery cell 10, the first region 61 and the back surface connection electrode 13B of the light-receiving surface bus bar electrode 12B are disposed at corresponding positions in the plane of the semiconductor substrate 11, and in the in-plane direction of the solar cell unit 10 Since the area of the first region 61 of the light-receiving surface bus bar electrode 12B is substantially the same as the area of the back surface connection electrode 13B, the welding area of the light-receiving surface bus bar electrode 12B and the lead wire 20 and the welding area of the back surface connection electrode 13B and the lead wire 20 become It is roughly equal. Thereby, the fixed position of the welded light-receiving surface bus bar electrode 12B and the lead wire 20 and the fixed position of the soldered back surface connection electrode 13B and the lead wire 20 are at the same position in the surface of the semiconductor substrate 11, and the solar battery cell 10 can be used. The balance of the internal stress in the light receiving surface side and the back surface side of the solar battery cell 10 is obtained. Therefore, the solar battery unit 10 can suppress the bending of the solar battery cells 10 which are caused by the welding leads 20 to the solar battery cells 10 when the solar battery module 100 is manufactured. Therefore, the solar battery unit 10 can reduce the breakage rate of the solar battery unit 10 caused by the bending of the solar battery unit 10 when the solar battery module 100 is manufactured.

Therefore, since the area of the first region 61 of the light-receiving surface bus electrode 12B in the in-plane direction of the solar battery cell 10 and the area of the back surface connection electrode 13B are correctly formed in the same area, the light-receiving surface side of the solar battery cell 10 can be obtained with high precision. The balance of the above internal stresses in the back side.

Further, in the solar battery unit 10, as described above, it is possible to suppress the bending of the solar battery cell 10 when the solar battery module 100 is manufactured, and it is possible to reduce the cost of the semiconductor substrate 11 by using the thinner semiconductor substrate 11 in accordance with the thinning of the semiconductor substrate 11. It can correspond to the realization of the inexpensive solar cell unit 10.

Moreover, the configuration of the solar battery cell 10 of the above-described first embodiment is an example, and the structure of the large-sized solar battery cell is not limited to the above description.

In addition, in the case of the seventh embodiment, the number of the light-receiving surface bus bar electrodes 12B and the back surface connection electrode 13B is four, but the number of the light-receiving surface bus bar electrodes 12B and the back surface connection electrode 13B is not limited to The above description.

Next, a method of manufacturing the solar battery cell 10 of the first embodiment will be described with reference to Figs. 15 to 22. Fig. 15 is a flow chart for explaining the procedure of the manufacturing steps of the solar battery cell 10 according to the first embodiment of the present invention. Figs. 16 to 22 are cross-sectional views showing main parts of a manufacturing process of the solar battery cell 10 according to the first embodiment of the present invention. Further, in the figures 20 to 22, the map corresponding to Fig. 9 is shown.

First, as shown in Fig. 16, the semiconductor substrate 1 is prepared, for example, in a square-shaped p-type single crystal germanium substrate which is most used for solar cells for people's livelihood. Here, the thickness and size of the semiconductor substrate 1 are not particularly limited. However, as an example, the thickness of the semiconductor substrate 1 is 200 μm, and the outer dimension of the semiconductor substrate 1 in the plane direction is 156 mm × 156 mm.

Since the semiconductor substrate 1 is produced by the wire saw blade cooling and solidified molten yttrium formed by the ruthenium ingot, the surface is left with damage on the surface. Then, first, the damaged layer is removed, and the surface is etched by the immersion semiconductor substrate 1 in an acid solution or a heated alkali solution to remove the damaged region which occurs near the surface of the semiconductor substrate 1 when the semiconductor substrate 1 is cut out. An example of the alkali solution is an aqueous sodium hydroxide solution.

Then, in the step S10, fine unevenness (not shown) is formed as a texture on the surface on the light-receiving surface side of the semiconductor substrate 1. The fine unevenness is formed, for example, by immersing the semiconductor substrate 1 in a mixed solution of sodium hydroxide and isopropyl alcohol in an alkaline aqueous solution, and performing wet etching of the semiconductor substrate 1.

Next, in step S20, the semiconductor substrate 1 having fine texture as a texture on the surface thereof is placed in a thermal diffusion furnace, heated in air of phosphorus (P) of an n-type impurity, and pn junction is formed on the entire substrate of the semiconductor substrate 1. According to this step, phosphorus is diffused from the surface of the semiconductor substrate 1 to the semiconductor substrate 1. As shown in Fig. 17, the n-type impurity diffusion layer 2 is formed on the surface layer of the semiconductor substrate 1, thereby forming a pn junction. Thereby, the semiconductor substrate 11 which comprises a pn junction is obtained.

For the formation of the n-type impurity diffusion layer 2, for example, the semiconductor substrate 1 is placed in a thermal diffusion furnace, and the mixed air of phosphorus oxychloride (POCl ₃ ) gas and oxygen is heated at a temperature of, for example, about 750 ° C to 900 ° C. The concentration of phosphorus diffused to the surface layer of the semiconductor substrate 1 can be controlled by conditions such as the concentration of the phosphorus oxychloride gas, the air temperature, and the heating time. Here, on the surface after the formation of the n-type impurity diffusion layer 2, a phosphorus glass layer (not shown) in which a mixture of a tantalum oxide film containing phosphorus oxide as a main component and a phosphorus oxide is formed is formed. Therefore, the phosphorus glass layer on the surface of the n-type impurity diffusion layer 2 is removed by a chemical agent such as a hydrofluoric acid aqueous solution.

Next, in step S30, a step of pn separating the back surface electrode 13 of the electrically insulating p-type electrode and the light-receiving surface electrode 12 of the n-type electrode is performed, and the n-type impurity diffusion layer 2 at the end of the semiconductor substrate 11 is removed as shown in FIG. . Since the n-type impurity diffusion layer 2 is formed similarly on the surface of the semiconductor substrate 1, the light-receiving surface 11A and the back surface 11B of the semiconductor substrate 11 are electrically connected. Therefore, when the back surface electrode 13 and the light-receiving surface electrode 12 are formed in the semiconductor substrate 11, the back surface electrode 13 and the light-receiving surface electrode 12 are electrically connected. In order to cut off this electrical connection, pn separation is performed. For example, pn separation is exemplified by end face etching by plasma etching or melt separation by laser processing.

Next, in step S40, on the light-receiving surface side of the semiconductor substrate 11, that is, on the n-type impurity diffusion layer 2, for the surface protection and photoelectric conversion efficiency improvement, as shown in Fig. 19, a tantalum nitride (SiN) film is formed as The anti-reflection film 3. For the formation of the anti-reflection film 3, for example, a plasma-chemical vapor deposition (PECVD) method is used to form a tantalum nitride film as a reflection preventing film using a mixed gas of silane and ammonia. 3. The film thickness and refractive index of the anti-reflection film 3 are set to values that most suppress light reflection.

Next, an electrode is formed. First, in step S50, the light-receiving surface electrode 12 is printed on the light-receiving surface side of the semiconductor substrate 11 by screen printing. In other words, as shown in Fig. 20, the silver electrode paste 12a containing the electrode material paste of the silver and the glass frit is printed on the light-receiving surface side of the semiconductor substrate 11 as the light-receiving surface electrode 12 shape. Here, the silver electrode paste 12a is printed in the shape of the light-receiving surface bus bar electrode 12B including the plurality of first regions 61 and the plurality of second regions 62 as shown in FIGS. 7 and 11. Thereafter, the silver electrode paste 12a is dried.

Next, in step S60, the back surface electrode 13 is printed on the back surface of the semiconductor substrate 11 by screen printing. The printing of the back surface collector electrode 13A and the printing of the back surface connection electrode 13B are performed first, but the case where the back surface connection electrode 13B is printed first is shown here.

Next, as shown in Fig. 21, on the back surface of the semiconductor substrate 11, a silver electrode paste 13b containing an electrode material paste of silver and glass frit is printed in the shape of the back surface connection electrode 13B. The silver electrode paste 13b is printed on the surface of the back surface of the semiconductor substrate 11 at a position corresponding to the position where the first region 61 of the light-receiving surface bus bar electrode 12B is formed on the light-receiving surface of the semiconductor substrate 11, and is printed using a printing mask having an opening pattern. . Thereafter, the silver electrode paste 13b was dried at a temperature of 200 ° C for 5 minutes.

Next, as shown in Fig. 21, on the back surface of the semiconductor substrate 11, an aluminum electrode paste 13a which is an electrode material paste containing aluminum and a glass frit is printed in the shape of the back surface collector electrode 13A. The aluminum electrode paste 13a is printed on the back surface of the semiconductor substrate 11, the printing region of the back surface connection electrode 13B, and the entire back surface except a part of the outer edge region, using a printing mask having an opening pattern. Further, at least a part of the aluminum electrode paste 13a is printed in a state of being electrically connected to the silver electrode paste 13b. Thereafter, the aluminum electrode paste 13a was dried at a temperature of 200 ° C for 5 minutes.

After that, in step S70, the electrode baking process for performing the baking process of the printing paste is performed, and the electrode paste printed on the semiconductor substrate 11 is fired, and as shown in Fig. 22, the light-receiving surface grating as the light-receiving surface electrode 12 is obtained. The electrode 12G and the light-receiving surface bus electrode 12B and the back surface collector electrode 13A and the back surface connection electrode 13B as the back surface electrode 13. The firing is carried out in an infrared heating furnace at about 750 ° C to 900 ° C in atmospheric air. The selection of the firing temperature is carried out in consideration of the structure of the solar battery cell 10 and the type of the electrode paste.

On the light-receiving surface side of the semiconductor substrate 11, the anti-reflection film 3 that penetrates the silver insulating film of the light-receiving surface electrode 12 is fired, and the n-type impurity diffusion layer 2 and the light-receiving surface electrode 12 are electrically connected. Therefore, the n-type impurity diffusion layer 2 can obtain good resistive bonding with the light-receiving surface electrode 12.

On the other hand, the aluminum electrode paste 13a and the silver electrode paste 13b are fired on the back surface side of the semiconductor substrate 11, and the back surface collector electrode 13A and the back surface connection electrode 13B are formed, and an alloy portion (not shown) made of aluminum and silver is formed. .

When the back surface collector electrode 13A is formed, the aluminum electrode paste 13a also reacts with the p-type single crystal ruthenium on the back surface of the semiconductor substrate 11, and is cured by the reaction to form a p+ layer BSF layer 4 containing aluminum. In other words, in the n-type impurity diffusion layer 2 formed on the back surface 11B side of the semiconductor substrate 11, a region directly under the back surface collector electrode 13A is converted into the BSF layer 4 by diffusion of aluminum. Further, in the n-type impurity diffusion layer 2 formed on the back surface side of the semiconductor substrate 11, in a region other than directly below the back surface collector electrode 13A, the diffusion aluminum becomes a p-type region.

Next, a method of manufacturing the solar battery module 100 including the solar battery unit 10 of the first embodiment will be described. Fig. 23 is a flow chart showing the procedure of the method of manufacturing the solar battery module 100 according to the first embodiment of the present invention.

First, in step S110, the light-receiving surface bus bar electrode 12B of one of the solar battery cells 10 is joined to the back surface connection electrode 13B of the other solar cell unit 10 via the bonding wire 20, and the plurality of solar cells are electrically connected by the lead wires 20. 10, forming a solar cell string 50.

Then, in the step S120, the sheet of the light-receiving surface side sealing material 33, the solar cell string 50, the sheet of the back side sealing material 34, and the back surface protecting portion 32 are sequentially laminated on the light-receiving surface protecting portion 31 to form a laminated body.

Next, in step S130, the laminated body is attached to the laminate device, and heat treatment and lamination processing are performed for 30 minutes or so at a temperature of, for example, 140 ° C or more and 160 ° C or less. Thereby, each member of the laminated body is integrated via the light-receiving surface side sealing material 33 and the back surface side sealing material 34, and the solar cell module 100 is obtained.

Thereafter, the outer edge portion of the solar cell module 100 is held by the frame 40 throughout the entire circumference.

As described above, in the solar battery cell 10 of the first embodiment, a plurality of through holes 60 are provided in the light receiving surface bus bar electrode 12B. Thereby, in the solar battery cell 10, the amount of use of the electrode material used in the light-receiving surface bus bar electrode 12B can be reduced, and the manufacturing cost of the solar cell unit 10 can be reduced.

Further, in the solar battery cell 10 of the first embodiment, the first region 61 and the back surface connection electrode 13B of the light-receiving surface bus bar electrode 12B are disposed at positions corresponding to the surface of the semiconductor substrate 11, with the semiconductor substrate 11 interposed therebetween. The semiconductor substrate 11 is opposed to each other in the thickness direction. As a result, the solar battery unit 10 can suppress the bending of the solar battery unit 10 that causes the solar battery unit 10 to solder the lead 20 when the solar battery module 100 is manufactured, and can cause the solar battery unit 10 to bend when the solar battery module 100 is manufactured. The breakage rate of the solar cell unit 10 is lowered.

In the solar battery cell 10 of the first embodiment, the light-receiving surface bus bar electrode 12B has the same width in the longitudinal direction, and both ends in the second direction are linear in parallel to the first direction. The width of the light-receiving surface bus bar electrode 12B is the same as the width of the lead wire 20 which is formed to have the same width in the longitudinal direction as the width of the light-receiving surface bus bar electrode 12B. Then, when the solar cell module 100 is fabricated, the position of the side surface 12Ba of the light-receiving surface bus bar electrode on both sides of the light-receiving surface bus bar electrode 12B in the second direction and the lateral direction of the lead wires on both sides of the lead wire 20 in the second direction are formed. The position of the side surface 20b is located at the same position in the in-plane direction of the light receiving surface 11A of the semiconductor substrate 11. The position of the side surface 12Ba of the light-receiving surface bus bar electrode and the position of the side surface 20b of the lead wire in the lateral direction are located at the same position in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. In the solar cell unit 10, the amount of light received by the solar cell unit 10 caused by the light-receiving surface bus bar electrode 12B exposed from the lead 20 in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11 is prevented from decreasing, and the photoelectric conversion efficiency can be prevented from being lowered. .

Further, in the solar battery unit 10, since the solar battery unit 10 can be prevented from being bent when the solar battery module 100 is manufactured, the cost of the semiconductor substrate 11 can be reduced by using the thinner semiconductor substrate 11, and the realization of the inexpensive solar battery unit 10 can be achieved.

Therefore, according to the solar battery cell 10 of the first embodiment, it is possible to suppress the effect of bending the solar battery cells caused by the bonding of the solar battery cells.

 [Second embodiment]  

Fig. 24 is a plan view showing the solar battery cell 110 of the second embodiment of the present invention as seen from the side of the light receiving surface. Fig. 25 is a plan view showing the solar battery cell 110 according to the second embodiment of the present invention from the back side facing the side opposite to the light receiving surface side. Fig. 26 is a cross-sectional view showing the main part of the configuration of a solar battery module according to a second embodiment of the present invention. Fig. 26 is a cross-sectional view showing the main part of the solar battery module of the second embodiment, which is constituted by the solar battery unit 110, corresponding to Fig. 3; A cross-sectional view of the solar battery unit 110 in Fig. 26 is a cross-sectional view of a main portion in the line XXII-XXIII in Fig. 24. Fig. 27 is a view showing a configuration condition of the light-receiving surface electrode 112 of the solar battery cell 110 according to the second embodiment of the present invention. Fig. 28 is a view showing a configuration condition of the back surface connection electrode 113B of the solar battery cell 110 according to the second embodiment of the present invention.

In the solar battery cell 110 of the second embodiment, the light-receiving surface electrode 12 including the light-receiving surface electrode 12G and the light-receiving surface bus electrode 12B includes a light-receiving surface including the light-receiving surface electrode 12G and the light-receiving surface bus electrode 112B. Electrode 112. Further, the solar battery unit 110 includes a back surface electrode 113 including a back surface collecting electrode 13A and a back surface connecting electrode 113B instead of the back surface electrode 13 including the back surface collecting electrode 13A and the back surface connecting electrode 13B. The solar battery cell 110 has the same configuration as the solar battery cell 10 of the first embodiment except for the light-receiving surface electrode 112 and the back surface electrode 113. In the solar battery unit 110, the same components as those of the solar battery unit 10 of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The light-receiving surface bus bar electrode 112B is different from the arrangement of the light-receiving surface bus bar electrode 12B. The back surface connection electrode 113B is different from the arrangement of the back surface connection electrode 13B.

The light-receiving surface bus electrode 112B is provided in four solar battery cells 110. The solar battery unit 110 has a rectangular semiconductor substrate 11 and has a pair of end portions which are parallel to each other, and a first end side portion and a second end side portion. Here, the first end side portion is a side on the one end 101 side of one end portion of the solar battery cell 110 in the first direction. Further, the second end portion is the other end portion of the solar battery cell 110 in the first direction, parallel to the one end 101, and the other end 102 side opposite to the one end 101 in the first direction. In each of the light-receiving surface bus electrodes 112B, the first region 611, the first region 612, the first region 613, and the first region 614 are disposed from the one end 101 side to the other end 102 side of the solar battery cell 110 in the first direction. The first region 615, the first region 616, the first region 617, and the first region 618.

Here, the one end 101 side of the solar battery cell 110 in the first direction is connected to the end side of the arrangement side of the solar cell unit 110 adjacent to the light-receiving surface bus bar electrode 112B by the lead wire 20, corresponding to the 24th to 26th views. The left side of the solar battery unit 110. In the solar battery unit 110, the end portion on the side where the adjacent solar battery cells 110 are disposed on the light-receiving surface bus bar electrode 112B is connected to the end portion on the light-receiving side.

Further, the other end 102 side of the solar battery cell 110 in the first direction is connected to the end portion side of the adjacent solar battery cell 110 on the side where the light-receiving surface bus bar electrode 112B is not disposed, and corresponds to the 24th to 26th views. The right side of the solar battery unit 110. In the solar battery unit 110, the end portion on the side where the adjacent solar battery cells 110 are not disposed on the light-receiving surface bus bar electrode 112B is connected by the lead wires 20, and is the end portion on the light-receiving side that is not connected to each other.

Further, the length of the first region in the longitudinal direction of the light-receiving surface bus bar electrode 112B is the length of the first region in the first direction, and the length of the first region 611 is the length of the first region length A1 and the length of the first region 612. The length of the first region length A2, the first region 613 is the first region length A3, the length of the first region 614 is the first region length A4, and the length of the first region 615 is the first region length A5 and the first region 616. The length of the first region is A6, the length of the first region 617 is the length A7 of the first region, and the length of the first region 618 is the length A8 of the first region.

Further, in the first direction, the distance from the one end 101 of the solar battery cell 110 to the first region 611 is the distance B1, the distance between the first region 611 and the first region 612 is the distance B2, the first region 612, and the first region. The distance between 613 is distance B3, the distance between first region 613 and first region 614 is distance B4, the distance between first region 614 and first region 615 is distance B5, first region 615 and first The distance between the regions 616 is the distance B6, the distance between the first region 616 and the first region 617 is the distance B7, the distance between the first region 617 and the first region 618 is the distance B8, and the first region 618 to the sun. The distance from the other end 102 of the battery unit 110 is the distance B9.

The back surface connection electrode 113B is provided in four solar battery cells 110. The back surface connection electrode 113B of the same number as the number of the first regions 61 of the light-receiving surface bus bar electrode 112B is provided in the in-plane corresponding to the first region 61 of the semiconductor substrate 11. In each of the back surface connection electrodes 113B, the back surface connection electrode 1131, the back surface connection electrode 1132, the back surface connection electrode 1133, the back surface connection electrode 1134, and the back surface connection electrode are disposed from the one end 101 side of the solar cell unit 110 to the other end 102 side in the first direction. 1135, a back surface connection electrode 1136, a back surface connection electrode 1137, and a back surface connection electrode 1138.

The back surface connection electrode 113B is disposed at a position corresponding to the first region 61 in the plane of the semiconductor substrate 11. Therefore, in the in-plane of the semiconductor substrate 11, the back surface connection electrode 1131 is disposed at a position corresponding to the first region 611, the back surface connection electrode 1132 is disposed at a position corresponding to the first region 612, and the back surface connection electrode 1133 is disposed in the first region 613. In the corresponding position, the back surface connection electrode 1134 is disposed at a position corresponding to the first region 614, the back surface connection electrode 1135 is disposed at a position corresponding to the first region 615, and the back surface connection electrode 1136 is disposed at a position corresponding to the first region 616, and the back surface The connection electrode 1137 is disposed at a position corresponding to the first region 617, and the back surface connection electrode 1138 is disposed at a position corresponding to the first region 618.

Here, in the first direction, the one end 101 side of the solar battery cell 110 in the first direction is connected to the end portion side of the back surface connection electrode 113B adjacent to the undisposed side of the solar battery cell 110 by the lead wire 20. In the solar battery unit 110, the end portion of the back surface connection electrode 113B adjacent to the undisposed side of the solar battery cell 110 is connected by the lead wire 20, and is the end portion on the back side which is not connected to each other.

Further, on the other end 102 side of the solar battery cell 110 in the first direction, the end portion side of the back surface connection electrode 113B adjacent to the arrangement side of the solar battery cells 110 is connected by a lead wire 20. In the solar battery unit 110, the end portion of the back surface connection electrode 113B adjacent to the arrangement side of the solar battery cell 110 is connected by the lead wire 20, and the end portion on the back side of the back side is connected.

Further, the length of the back surface connection electrode 113B in the first direction is such that the length of the back surface connection electrode 1131 is the length of the back surface connection electrode C1, the length of the back surface connection electrode 1132 is the length of the back surface connection electrode C2, and the length of the back surface connection electrode 1133 is the back side connection. The length of the electrode length C3, the length of the back surface connection electrode 1134 is the length of the back surface connection electrode C4, the length of the back surface connection electrode 1135 is the length of the back surface connection electrode C5, the length of the back surface connection electrode 1136 is the length of the back surface connection electrode C6, and the length of the back surface connection electrode 1137 is The length of the back surface connection electrode length C7 and the back surface connection electrode 1138 is the back surface connection electrode length C8.

Further, in the first direction, the distance from the one end 101 of the solar battery cell 110 to the back surface connection electrode 1131 is the distance D1, the distance between the back surface connection electrode 1131 and the back surface connection electrode 1132 is the distance D2, the back surface connection electrode 1132 and the back surface connection electrode The distance between 1133 is the distance D3, the distance between the back connection electrode 1133 and the back connection electrode 1134 is the distance D4, the distance between the back connection electrode 1134 and the back connection electrode 1135 is the distance D5, and the back connection electrode 1135 is connected to the back side. The distance between the electrodes 1136 is the distance D6, the distance between the back surface connection electrode 1136 and the back surface connection electrode 1137 is the distance D7, the distance between the back surface connection electrode 1137 and the back surface connection electrode 1138 is the distance D8, and the back surface connection electrode 1138 to the sun. The distance from the other end 102 of the battery unit 110 is the distance D9.

The semiconductor substrate 11 is, for example, a square shape having a side length of 156 mm. The first region length A1, the first region length A2, the first region length A3, the first region length A4, the first region length A5, the first region length A6, and the first region length A7 are, for example, 5 mm. The first region length A8 is longer than the first region length A1 to the first region length A7, and is, for example, 11 mm. The distance B1 and the distance B9 are, for example, 0.5 mm. The distance B2 and the distance B8 are, for example, 7 mm. The distance B3, the distance B4, the distance B5, the distance B6, and the distance B7 are, for example, 19 mm.

The back surface connection electrode length C1, the back surface connection electrode length C2, the back surface connection electrode length C3, the back surface connection electrode length C4, the back surface connection electrode length C5, the back surface connection electrode length C6, the back surface connection electrode length C7, and the back surface connection electrode length C8 are, for example, 5mm. The distance D9 is longer than the distance D1 and has a relationship of distance D1 < distance D9. For example, the distance D1 = 0.5 mm and the distance D9 = 6.5 mm. The distance D2 and the distance D8 are, for example, 7 mm. The distance D3, the distance D4, the distance D5, the distance D6, and the distance D7 are, for example, 19 mm.

On the light-receiving surface side of the solar cell unit 110, it is preferable to provide the light-receiving surface bus bar electrode 112B to both ends of the solar cell unit 110 in the first direction. On the other hand, on the back side of the solar battery cell 110, particularly in the other end 102 side which is the lead connection side, it is preferable to lengthen the distance from the end surface of the solar battery cell 110 to the back surface connection electrode 113B in the first direction.

The light receiving surface side of the solar cell unit 110 has a convex curved surface. That is, since the back surface collector electrode 13A using the electrode material containing aluminum is formed on the entire back surface of the solar cell unit 110, the bending due to the difference in thermal expansion coefficient between aluminum and tantalum occurs in the solar cell unit 110. In general, since the coefficient of thermal expansion of aluminum is larger than the coefficient of thermal expansion of ytterbium, after the heat treatment for firing of the electrode, the light-receiving surface side is convexly curved in the solar cell unit 110.

Then, when the lead wire 20 is soldered to the solar battery cell 110, since the light receiving surface is convex, the stress of the lead wire 20 is peeled off in the vertical direction of the light receiving surface of the solar battery cell 110 between the solar battery cell 110 and the lead wire 20. Thus, the stress of the peeling becomes maximum at the end of the solar cell unit 110.

Here, on the light-receiving surface side of the solar cell unit 110, since the light-receiving surface bus bar electrode 112B is provided up to both ends of the semiconductor substrate 11 in the first direction, the light-receiving surface bus bar electrode on the end side of the solar cell unit 110 can be reinforced. Bond strength between 112B and lead 20. In other words, as described above, the light-receiving surface bus bar electrode 12G is formed until the distance B1 and the distance B9 in the first direction form a position of 0.5 mm. Then, the light-receiving surface bus bar electrode 112B is provided until the light-receiving surface bus bar electrode 12G is received at both ends in the first direction, and the light-receiving surface bus bar electrode 112B is provided until the position of both ends of the semiconductor substrate 11 in the first direction. Thereby, the solar battery unit 110 can further strengthen the joint strength between the light-receiving surface bus bar electrode 112B and the lead wire 20 in the end side. Then, both ends of the light-receiving surface bus bar electrode 112B in the first direction are formed by the first region, and the joint strength between the light-receiving surface bus bar electrode 112B and the lead wire 20 in the end portion side can be enhanced. When the both ends of the light-receiving surface bus bar electrode 112B in the first direction are formed by the second region 62, the end portion of the light-receiving surface bus bar electrode 112B is welded only to the lead wire 20 by the connecting portion 63, and the joint strength is lowered.

Further, in the solar cell unit 110, the semiconductor substrate 11 has a rectangular shape, and has a first end side portion which is an end portion of the solar cell unit 110 in the first direction, and a sun opposite to the first end side portion in the first direction. The end of the battery unit 110 is the second end portion. Then, the distance between the back surface connection electrode 113B adjacent to the second end side portion and the second end side portion is longer than the distance between the back surface connection electrode 113B and the first end side portion of the adjacent first end side portion.

The solar battery cell 10 of the first embodiment has a symmetrical configuration with respect to the center position in the first direction in the first direction. Therefore, when the solar battery cells 10 are connected by the lead wires 20, as shown in FIG. 3, the lead wires 20 are continuously disposed from the lower left to the upper right in the drawing, and the configuration between the adjacent solar battery cells 10 is connected, and for the third. In the adjacent solar battery cells 10 shown in the drawing, the lead wires 20 are arranged from the upper left to the lower right in the drawing, and the configuration between the adjacent solar battery cells 10 is equivalent.

On the other hand, in the solar battery unit 110 of the second embodiment, the central position in the first direction has an asymmetrical configuration in the first direction. Therefore, when the solar battery cells 110 are connected by the lead wires 20, as shown in FIG. 26, the lead wires 20 are continuously disposed from the lower left to the upper right in the drawing, and the configuration between the adjacent solar battery cells 110 is connected, and for the 26th. In the adjacent solar battery cells 110 shown in the drawing, the lead wires 20 are arranged from the upper left to the lower right in the drawing, and the configuration between the adjacent solar battery cells 110 is not equivalent.

Here, the lead wires 20 are continuously disposed from the lower left to the upper right, and the configuration between the adjacent solar battery cells 10 is connected. As shown in FIG. 3, the solar battery cells 10 disposed in the left and right directions are connected to the rear side of the solar battery cells 10 on the left side. The electrode 13B is connected to the light-receiving surface bus bar electrode 12B of the solar battery cell 10 on the right side by a lead wire 20. Further, the lead wires 20 are arranged from the upper left to the lower right, and the configuration between the adjacent solar battery cells 10 is connected to the solar cell unit 10 disposed on the left and right sides, and the light receiving surface of the solar cell unit 10 on the left side is connected to the drain electrode 12B and the right side. The back surface of the solar battery cell 10 is connected to the electrode 13B by a lead wire 20.

The rear surface side of the solar battery cell 110 having the above-described configuration is the end surface to the back surface of the solar battery cell 110 which is lengthened on the side of the rear side of the solar battery cell 110 on the side of the interconnection side, that is, the other end 102 side of the solar battery cell 110. The distance of the electrode 113B, that is, the distance D9 from the back surface connection electrode 1138 to the other end 102 of the solar cell unit 110 has the following effects.

As shown in Fig. 26, in the solar battery module of the second embodiment, a plurality of solar battery cells 110 are connected by leads 20, and the lead wires 20 are connected in a curved shape from the back side of one of the solar battery cells 110a to the other solar battery. The light receiving surface side of the unit 110b. In other words, in the solar battery module according to the second embodiment, the second end portion of the solar battery unit 110 disposed on the left side in FIG. 26 and the other solar battery unit 110 disposed on the right side in FIG. 26 are provided. The first end side portion is disposed opposite to each other, and one of the solar battery cells 110 and the other solar battery unit 110 are adjacent to each other in the first direction. Further, the solar battery module according to the second embodiment has the lead wire 20 that connects the back surface connection electrode 113B of one of the solar battery cells 110 and the light receiving surface bus bar electrode 112B of the other solar battery cell 110. Then, the lead wire 20 is connected to the light-receiving surface of the solar cell unit 110 on the second end side and the light-receiving surface of the other solar cell 110 on the light-receiving surface of the other end side.

The distance D1 is the distance D9, and since the lead wire 20 is disposed on the light-receiving surface side of the solar battery cell 110b from the back side of the solar battery cell 110a, the length of the bent portion 20a of the curved lead wire 20 is long, and the lead wire 20 is long. The bending radius of the curved portion 20a is increased to reduce the stress concentration on the curved portion 20a of the lead wire 20. In particular, although the solar cell module is expected to have a life of more than 10 years, it is caused by a difference in linear expansion coefficient between the light-receiving surface glass and the lead 20 of the light-receiving surface protecting portion 31, and the curved portion of the temperature-circulating lead 20 is turned on day and night. Repeated stress occurs in 20a and breaks, which becomes the main cause of failure. Here, by increasing the bending radius of the curved portion 20a of the lead 20, it is possible to reduce the repeated stress applied to the curved portion 20a, and it is possible to realize a solar battery module excellent in long-term reliability.

In the solar battery unit 110, the first region 61 other than the end portion side on the non-interconnecting side of the light receiving surface side, that is, the first region 61 and the back surface connecting electrode 113B other than the other end 102 side are preferably provided on the light receiving surface and the back surface. The corresponding position in . In other words, it is preferable that the first region 611 to the first region 617 are provided at positions corresponding to the inside of the surface of the solar cell unit 110 from the back surface connection electrode 1131 to the back surface connection electrode 1137. Thereby, the fixed position of the light-receiving surface bus bar electrode 112B and the lead 20 and the fixed position of the back surface connection electrode 113B and the lead 20 by soldering are the same in the surface of the semiconductor substrate 11 except for the first region 618 and the back surface connection electrode 1138. s position. Thereby, the solar battery unit 110 can suppress the bending of the solar battery unit 110 which welds the lead wires 20 to the solar battery cells 110 when the solar battery module is manufactured, similarly to the above-described solar battery unit 10. Therefore, the solar battery unit 110 can reduce the breakage rate of the solar battery unit 110 caused by the bending of the solar battery unit 110 when the solar battery module is manufactured.

In the light-receiving surface bus bar electrode 112B, the interval between the adjacent first regions in the first-direction end portion is preferably the first direction of the interval between the adjacent first regions in the central portion including the first direction. The interval between adjacent first regions in the inner side is short. In other words, in the light-receiving surface bus bar electrode 112B, the length of the second region on the end side in the first direction is preferably shorter than the length of the second region on the inner side in the first direction. Therefore, it is preferable to form (distance B2 = distance D2 = distance B8 = distance D8) < (distance B3 = distance D3, distance B4 = distance D4, distance B5 = distance D5, distance B6 = distance D6, distance B7 = distance D7) .

As described above, when the solar battery cell 110 is soldered to the lead wire 20, the solar battery cell 110 has a convex shape on the light receiving surface side, and the lead wire is peeled off between the solar battery cell 110 and the lead wire 20 in the vertical direction of the light receiving surface of the solar battery cell 110. The stress of 20 becomes maximum on the end side in the first direction. On the other hand, the length of the second region on the end side in the first direction is shorter than the length of the second region on the inner side in the first direction, so that the light-receiving surface bus bar electrode on the end side in the first direction can be reinforced. Bond strength of 112B to lead 20.

As described above, in the solar battery cell 110 of the second embodiment, in addition to the first region 618 and the back surface connection electrode 1138, the fixing position of the light-receiving surface bus bar electrode 112B and the lead wire 20 and the back surface connection electrode 113B and the lead wire 20 by soldering are used. The fixed position is the same position in the plane of the semiconductor substrate 11. Therefore, the solar battery unit 110 can reduce the breakage rate of the solar battery unit 110 caused by the bending of the solar battery unit 110 when the solar battery module is manufactured, similarly to the solar battery unit 10 described above.

Further, in the solar battery unit 110 of the second embodiment, the end portion on the side of the back side of the solar battery cell 110, that is, the other end 102 side of the solar battery unit 110, lengthens the end surface to the back surface of the solar battery unit 110. The distance of the electrode 113B. Therefore, the length of the curved portion 20a that bends the lead 20 connecting the adjacent solar battery cells 110 into a curved shape becomes long. Therefore, it is possible to reduce the stress concentration on the curved portion 20a of the lead 20, which is caused by the difference in the linear expansion coefficient between the light-receiving surface glass and the lead 20 of the light-receiving surface protecting portion 31, because the temperature cycle due to day and night can be reduced to the bending. The repetitive stress of the portion 20a can realize a solar cell module excellent in long-term reliability.

 [Third embodiment]  

Figure 29 is a cross-sectional view showing the configuration of a solar battery cell 210 according to a third embodiment of the present invention. Fig. 29 is a cross section through the through hole 60 along the longitudinal direction of the light receiving surface electrode 212, and the back surface collecting electrode 13A is omitted for easy understanding. Fig. 30 is a view showing a configuration condition of the light-receiving surface electrode 212 of the solar battery cell 210 according to the third embodiment of the present invention. Fig. 31 is a view showing a configuration condition of the back surface connection electrode 213B of the solar battery cell 210 according to the third embodiment of the present invention.

The solar battery cell 210 of the third embodiment includes a light-receiving surface electrode 212 having a light-receiving surface bus bar electrode 212B instead of the light-receiving surface bus bar electrode 112B. Further, the solar battery cell 210 of the third embodiment includes a back surface electrode 213 having a back surface connection electrode 213B instead of the back surface connection electrode 113B. The solar battery cell 210 has the same configuration as the solar battery cell 110 of the second embodiment except for the light-receiving surface electrode 212 and the back surface electrode 213. In the solar battery unit 210, the same components as those of the solar battery unit 10 of the first embodiment or the solar battery unit 110 of the second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

The light-receiving surface bus bar electrode 212B is different from the arrangement of the light-receiving surface bus bar electrode 112B. The back surface connection electrode 213B is different from the arrangement of the back surface connection electrode 113B.

The light-receiving surface bus bar electrode 212B is the same as the light-receiving surface bus bar electrode 112B, and four solar cell units 210 are provided. Further, in each of the light-receiving surface bus bar electrodes 212B, the first region 611, the first region 612, the first region 613, the first region 614, and the first region 615 are arranged along the first direction, similarly to the light-receiving surface bus bar electrode 112B. The first region 616, the first region 617, and the first region 618. Similarly to the back surface connection electrode 113B, the back surface connection electrode 213B is disposed in four rows along the first direction so as to be spaced apart from each other over substantially the entire length of the solar battery cell 210.

The back surface connection electrode 213B of the same number as the number of the first regions 61 of the light-receiving surface bus bar electrode 212B is provided in the in-plane corresponding to the first region 61 of the semiconductor substrate 11.

Then, the first region 61 and the back surface connection electrode 213B located on the inner side in the first direction other than the end portion side in the first direction of the light-receiving surface bus bar electrode 212B are seen from the vertical direction of the in-plane direction of the semiconductor substrate 11. In the case of the semiconductor substrate 11, the center position in the first direction is at the same position. That is, in the first direction, the center position of the first region 612 is located at the same position as the center position of the back surface connection electrode 1132. The center position of the first region 613 and the center position of the back surface connection electrode 1133, the center position of the first region 614, the center position of the back surface connection electrode 1134, the center position of the first region 615, and the center position of the back surface connection electrode 1135, The center position of the 1 region 616 and the center position of the back surface connection electrode 1136 and the center position of the first region 617 are also the same as the center position of the back surface connection electrode 1137.

On the other hand, when the first region 611 and the back surface connection electrode 1131 located on the end side in the first direction of the light-receiving surface bus bar electrode 212B are seen from the vertical direction of the in-plane direction of the semiconductor substrate 11, the first semiconductor substrate 11 is seen. The center position in the direction is not at the same position. That is, in the first direction, the center position of the first region 611 is different from the center position of the back surface connection electrode 1131. Similarly, in the first direction, the center position of the first region 618 is different from the center position of the back surface connection electrode 1138.

The arrangement pitch of the adjacent two first regions 61 in the inner side in the first direction is the same arrangement pitch. Further, the arrangement pitches of the adjacent two back surface connection electrodes 213B on the inner side in the first direction are all the same arrangement pitch. Then, the arrangement pitch of the adjacent two first regions 61 in the inner side in the first direction is the same as the arrangement pitch of the two back surface connection electrodes 213B adjacent to the inner side in the first direction. The arrangement pitch of the first region 61 is the distance between the center positions of the first regions 61 in the first direction. The arrangement pitch of the back surface connection electrodes 213B is the distance between the center positions of the back surface connection electrodes 213B in the first direction.

That is, the arrangement pitch of the first region 612 and the first region 613, the arrangement pitch of the first region 613 and the first region 614, the arrangement pitch of the first region 614 and the first region 615, and the first region 615 and the first region 616 Arrangement pitch, arrangement pitch of the first region 616 and the first region 617, arrangement pitch of the back surface connection electrode 1132 and the back surface connection electrode 1133, arrangement pitch of the back surface connection electrode 1133 and the back surface connection electrode 1134, and connection of the back surface connection electrode 1134 and the back surface The arrangement pitch of the electrodes 1135, the arrangement pitch of the back surface connection electrodes 1135 and the back surface connection electrodes 1136, and the arrangement pitch of the back surface connection electrodes 1136 and the back surface connection electrodes 1137 are the same arrangement pitch.

The first region length A2, the first region length A3, the first region length A4, the first region length A5, the first region length A6, and the first region length A7 are the same. The back surface connection electrode length C2, the back surface connection electrode length C3, the back surface connection electrode length C4, the back surface connection electrode length C5, the back surface connection electrode length C6, and the back surface connection electrode length C7 are the same. Therefore, the length A2 of the first region is longer than the length C2 of the back surface connection electrode.

The distance B3, the distance B4, the distance B5, the distance B6, and the distance B7 are the same. The distance D3, the distance D4, the distance D5, the distance D6, and the distance D7 are the same. Thus, the distance D3 is longer than the distance B3.

Therefore, (first region length A2+ distance B3) = (first region length A3 + distance B4) = (first region length A4 + distance B5) = (first region length A5 + distance B6) = (first region length A6 + distance B7) )=(back connection electrode length C2+ distance D3)=(back connection electrode length C3+distance D4)=(back connection electrode length C4+distance D5)=(back connection electrode length C5+distance D6)=(back connection electrode length C6+distance D7) ).

The center position of the first region 612 in the first direction coincides with the center position of the back surface connection electrode 1132 in the first direction, and the distance between the one end 101 of the solar battery cell 210 and the center position of the first region 612 in the first direction is The distance from the one end 101 of the solar cell unit 210 to the center position of the back surface connection electrode 1132 forms the same distance. That is, (distance B1 + first region length A1 + distance B2 + first region length A2/2) = (distance D1 + back surface connection electrode length C1 + distance D2 + back surface connection electrode length C2 / 2).

The center position of the first region 617 in the first direction coincides with the center position of the back surface connection electrode 1137 in the first direction, and the distance from the other end 102 of the solar battery cell 210 to the center position of the first region 617 in the first direction. The distance from the other end 102 of the solar cell unit 210 to the center position of the back surface connection electrode 1137 forms the same distance. That is, formation (distance B9 + first region length A8 + distance B8 + first region length A7/2) = (distance D9 + back surface connection electrode length C8 + distance D8 + back surface connection electrode length C7 / 2).

The first region length A1 is longer than the back surface connection electrode length C1. When the semiconductor substrate 11 is seen in a direction perpendicular to the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1131 in the first direction is disposed at a position where the first region 611 is overlapped inside the first region 611, that is, in the first direction, the back surface The connection electrode 1131 is located at a position included in the first region 611.

The first region length A8 is longer than the back surface connection electrode length C8. When the semiconductor substrate 11 is seen from the vertical direction of the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1138 is disposed in the first direction, and the first region 618 is placed on the inner side of the first region 618, that is, in the first direction, the back surface. The connection electrode 1138 is at a position included in the first region 618.

The back surface connection electrode length C1 and the back surface connection electrode length C8 are the same as the back surface connection electrode length C2.

In the first direction, the arrangement pitch of the adjacent two first regions 61 in the end portion side in the first direction is shorter than the arrangement pitch of the two first regions 61 adjacent to the inner side in the first direction. In other words, in the light-receiving surface bus bar electrode 212B, the interval between the adjacent two first regions 61 in the end portion side in the first direction is larger than the interval between the two first regions 61 adjacent to the central portion including the first direction. The interval between the adjacent two first regions 61 in the inner side in the first direction is short. Therefore, the distance B2 and the distance B8 are shorter than the distance B3, the distance B4, the distance B5, the distance B6, and the distance B7.

In the first direction, the arrangement pitch of the two adjacent back surface connection electrodes 213B in the end side in the first direction is shorter than the arrangement pitch of the two back surface connection electrodes 213B adjacent to the inside in the first direction. In other words, in the back surface connection electrode 213B of one row, the interval between the adjacent two rear surface connection electrodes 213B on the end side in the first direction is larger than the interval between the two rear connection electrodes 213B adjacent to the center portion including the first direction. The interval between the adjacent two back surface connection electrodes 213B on the inner side in the first direction is short. Therefore, the distance D2 and the distance D8 are shorter than the distance D3, the distance D4, the distance D5, the distance D6, and the distance D7.

In the solar battery cell 210 of the third embodiment, the total length of the first region of the light-receiving surface bus bar electrode 212B in the first direction is larger than that of the light-receiving surface bus bar electrode 112B of the solar battery cell 110 of the second embodiment. The total length of the 1 area is greatly lengthened. That is, as shown in Fig. 30, the total length of the first region in the solar battery cell 210, that is, the total of the first region length A1 to the first region length A8 is 76 mm. On the other hand, as shown in Fig. 27, the total length of the first region in the light-receiving surface bus bar electrode 112B of the solar battery cell 110 of the second embodiment is the total of the first region length A1 to the first region length A8. , is 46mm.

The lead wire 20 is soldered to the light-receiving surface bus bar electrode 212B, and the first region 61 and the lead wire 20 are mainly soldered. Therefore, the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction is approximately the total length of the first region. Therefore, the total length of the first region is considered to be the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead 20 in the first direction.

Further, in the solar battery cell 210 of the third embodiment, the total length of the first region of the light-receiving surface bus bar electrode 212B in the first direction is longer than the total length of the back surface connection electrode 213B in the first direction. Therefore, in the solar battery cell 210 of the third embodiment, the length of the connection region of the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction is longer than the length of the connection region of the back surface connection electrode 213B and the lead wire 20 in the first direction. long. That is, as shown in Fig. 31, the total length of the back surface connection electrode length C1 to the back surface connection electrode length C8 is 48 mm. On the other hand, as shown in Fig. 30, the total length of the first region, that is, the total length of the first region A1 to the first region length A8 is 76 mm.

In the solar battery cell 210, the back surface collector electrode 13A using an electrode material containing aluminum is formed on the entire back surface of the solar battery cell 210, and after the heat treatment for firing the electrode, the light-receiving surface side is convexly curved in the solar battery cell 210. Therefore, on the light-receiving surface side of the convex-curved solar battery cell 210, the stress of the lead wire 20 is peeled off between the electrode and the lead 20 more than the back surface side of the solar cell unit 210.

In the solar battery cell 210, the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead 20 in the first direction is longer than the length of the back surface connection electrode 213B in the first direction. Then, in the solar battery cell 210, the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction is formed, which is higher than the light-receiving surface bus bar electrode in the first direction of the solar battery cell 110 of the second embodiment. The length of the connection area between 112B and the lead 20 is long. Therefore, the solar battery cell 210 can increase the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction, thereby improving the bonding strength between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction. The peeling of the lead 20 is suppressed.

On the other hand, the back surface connection electrode 213B of the silver paste electrode formed by coating and firing the silver paste containing the electrode material of silver is formed in a state after the firing treatment than the light-receiving surface electrode 212 of the silver paste electrode. A composition with a large amount of glass. The silver paste electrode is composed of silver and glass after the firing treatment. Among the silver paste electrodes, silver has a function of causing a current to flow. Among the silver paste electrodes, the glass has a function of maintaining the bonding strength between the semiconductor substrate 11 and the electrodes.

When the light-receiving surface electrode 212 of the silver paste electrode and the back surface connection electrode 213B of the silver paste electrode are compared, the light-receiving surface electrode 212 has a higher ratio of silver in the electrode material than the back surface connection electrode 213B in order to lower the electric resistance in the electrode. In the light-receiving electrode 212, in order to reduce the electric resistance in the electrode, it is preferable to increase the ratio of silver in the electrode material as much as possible. On the other hand, on the back side of the solar battery cell 210, the back surface collector electrode 13A using an electrode material containing aluminum is used according to the current collecting function of the semiconductor substrate 11. Therefore, in the back surface connection electrode 213B, the ratio of the silver in the electrode material is lowered, and the ratio of the glass component in the electrode material is increased, whereby the bonding strength with the semiconductor substrate 11 can be improved.

Therefore, in the solar battery cell 210, the ratio of the glass component in the electrode material in the back surface connection electrode 213B in the state after the firing treatment is higher than that in the electrode material in the light-receiving surface electrode 212 in the state after the baking treatment. The ratio of the glass component is higher, and it is possible to maintain a high level of bonding strength between the semiconductor substrate 11 and the back surface connection electrode 213B without peeling off the back surface connection electrode 213B. In this way, even if the total length of the back surface connection electrode 213B in the first direction is shortened, the total length of the first region length of the light-receiving surface bus electrode 212B in the first direction is shorter, and the semiconductor substrate 11 can be maintained. The bonding strength between the back surface connection electrodes 213B is such that the back surface connection electrodes 213B are not peeled off.

As described above, in the solar battery cell 210 of the third embodiment, the first region 61 and the back surface connection electrode 213B of the light-receiving surface bus bar electrode 212B are disposed at positions corresponding to the surface of the semiconductor substrate 11. Therefore, the solar battery unit 210 can reduce the breakage rate of the solar battery unit 210 caused by the bending of the solar battery unit 210 when the solar battery module is manufactured, similarly to the solar battery unit 10 and the solar battery unit 110 described above.

Further, in the solar battery cell 210 of the third embodiment, the end surface to the back surface of the solar battery cell 210 is lengthened on the other end 102 side of the solar battery cell 210 at the end portion on the back side of the solar battery cell 210. The distance connecting the electrodes 213B. In the same manner as the solar battery cell 110 of the second embodiment, the stress concentration on the curved portion 20a of the lead 20 can be reduced, because the linear expansion coefficient of the light-receiving surface glass and the lead 20 which is the light-receiving surface protection portion 31 is different. The repetitive stress applied to the curved portion 20a by the temperature cycle of day and night can be reduced, and a solar cell module excellent in long-term reliability can be realized.

Further, in the solar battery cell 210 of the third embodiment, the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction is longer than the length of the connection region of the back surface connection electrode 213B and the lead wire 20 in the first direction. . Therefore, the solar battery cell 210 can increase the length of the connection region between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction, thereby improving the bonding strength between the light-receiving surface bus bar electrode 212B and the lead wire 20 in the first direction, thereby suppressing the lead wire. 20 peeling.

The configuration of the above-described embodiment is shown, and an example of the present invention is shown, and the technologies of the embodiments can be combined with other well-known technologies, and the invention can be omitted without departing from the scope of the present invention. Change part of the composition.

Claims (22)

 A solar cell unit comprising: a semiconductor substrate having a pn junction; a light-receiving surface bus bar electrode extending in a first direction on a light-receiving surface side of the semiconductor substrate; and a plurality of back-side connecting electrodes facing the semiconductor a rear surface side of the substrate opposite to the light-receiving surface is disposed to be dispersed along the first direction, wherein the light-receiving surface bus bar electrode is provided in the thickness direction of the light-receiving surface bus bar electrode along the first direction The plurality of through holes are disposed at a position of a region other than the plurality of through holes in the thickness direction of the semiconductor substrate in the thickness direction of the semiconductor substrate.    The solar cell unit according to claim 1, wherein the light-receiving surface bus bar electrode is in the first direction in a second direction orthogonal to the first direction in a plane of the semiconductor substrate. Parallel straight.    The solar battery unit according to claim 1 or 2, wherein the light-receiving surface bus bar electrode includes: a plurality of first regions, wherein the through holes are not provided in the first direction; and the plurality of second holes In the first direction, the through hole is provided in the first direction, and the back surface connection electrode is disposed at a position facing the plurality of first regions in a thickness direction of the semiconductor substrate.    The solar battery unit according to claim 3, wherein both ends of the light-receiving surface bus bar electrode in the first direction are constituted by the first region.    The solar battery unit according to the third aspect of the invention, wherein the first region adjacent to the first region in the first direction is spaced apart from the first region adjacent to the inner side in the first direction The interval between the two is short.    The solar battery unit according to the fourth aspect of the invention, wherein the first region adjacent to the first region in the first direction is spaced apart from the first region adjacent to the inner side in the first direction The interval between the two is short.    The solar cell according to claim 3, wherein the first region of the light-receiving surface bus bar electrode in the first direction is the back surface connection electrode disposed at a relative position in a thickness direction of the semiconductor substrate long.    The solar cell according to claim 4, wherein the first region of the light-receiving surface bus bar electrode in the first direction is the back surface connection electrode disposed at a relative position in a thickness direction of the semiconductor substrate long.    The solar cell according to claim 5, wherein the first region of the light-receiving surface bus bar electrode in the first direction is the back surface connection electrode disposed at a relative position in a thickness direction of the semiconductor substrate long.    The solar cell according to claim 6, wherein in the first direction, the first region of the light-receiving surface bus bar electrode is disposed at a position opposite to a thickness of the semiconductor substrate long.    The solar battery unit according to claim 1 or 2, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is adjacent The back surface connecting electrode of the first end side portion has a long distance from the first end side portion.    The solar battery unit according to claim 3, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 4, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 5, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 6, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 7, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 8, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 9, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    The solar battery unit according to claim 10, wherein the semiconductor substrate has a rectangular shape, and has a first end portion which is an end portion of the solar battery cell in the first direction, and the first direction a second end portion of the end portion of the solar cell opposite to the first end portion; a distance between the back surface connecting electrode adjacent to the second end portion and the second end portion is closer to the first The back surface connecting electrode at the one end portion has a long distance from the first end portion.    A solar cell module, comprising: a plurality of solar cell units, as described in any one of claims 1 to 19; and a lead, two of the solar cell units adjacent to each other in the first direction The light-receiving surface bus bar electrode of one of the solar battery cells is connected to the back surface of the other solar battery cell.    A solar cell module, comprising: the two solar cell units according to any one of claims 11 to 19, wherein the second end portion of one solar cell unit and the other solar cell unit The first end side portion is disposed opposite to each other in the first direction, and the lead wire connects the back surface connection electrode of the one solar cell unit and the light receiving surface bus bar of the other solar battery unit The lead wire is connected to the back surface connection electrode on the second end side of the one of the solar battery cells and the light receiving surface bus bar side on the first end side of the other solar cell.    The solar cell module according to claim 20, wherein a width of the light-receiving surface bus bar electrode is equal to a width of the lead wire, and the lead wire is orthogonal to the first direction in a surface of the semiconductor substrate. The position of both side surfaces of the light-receiving surface bus bar electrode in the second direction and the positions of both side surfaces of the lead wire in the second direction are located at the same position, and are overlapped and connected to the light-receiving surface bus bar electrode.