TWI692113B - Solar battery unit and solar battery module - Google Patents

Abstract

Including a semiconductor substrate, having a pn junction; a light-receiving surface bus electrode (12B) extending in the first direction on the light-receiving surface side of the semiconductor substrate; and a plurality of back-side connection electrodes facing the opposite side of the light-receiving surface in the semiconductor substrate On the back side of the device along the first direction. The light-receiving surface busbar electrode (12B) is provided with a plurality of through holes (60) penetrating in the thickness direction of the light-receiving surface busbar electrode along the first direction, and the back surface is connected to the electrode, and is arranged in the thickness direction of the semiconductor substrate with respect to the light-receiving surface bus The position of the row electrode (12B) except for the plurality of through holes (60).

Description

Solar battery unit and solar battery module

The invention relates to a solar cell unit forming a solar cell module by a lead wire and a solar cell module using the solar cell unit.

When modularizing solar cells, a plurality of solar cells are electrically connected in series, and under the target of taking out the electrical output, a lead wire composed of a rectangular copper wire is welded to each solar cell. The lead usually shrinks when it cools from a high temperature state to normal temperature directly after welding. Therefore, the lead wire is bent in the solar cell unit after welding due to the shrinkage of the lead wire. This bending of the solar battery cell is a cause of damage to the solar battery cell.

On the light-receiving surface and the back surface of the solar battery cell, a grid electrode for extracting electricity generated in the solar battery cell and a bus bar electrode for collecting electricity from all the grid electrodes are arranged. In order to improve the power generation area of the solar battery cell, the grid electrode is improved in thinning and mass quantization. On the other hand, because of the relationship between the securing of the bonding strength between the solar cell and the lead and the placement accuracy, it is difficult for the bus bar electrode to be thinned. In addition, because the heat treatment during the formation of the gate electrode and the bus bar electrode damages the power generation layer and lowers the power generation efficiency of the solar battery cell, high-priced silver must be used as the electrode material and the area should be reduced as much as possible.

Patent Document 1 discloses that 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 of the bus bar portion, and an electrode paste is printed by a screen printing method . According to the technique of Patent Document 1, while maintaining good bonding strength between the bus bar electrode and the lead, the area of the bus bar electrode can be reduced, but it cannot solve the bending of the solar cell unit after wire bonding.

On the other hand, on the back surface of the solar cell, a bus bar electrode is required for wire bonding to the back surface in the same way as the light-receiving surface. However, since a large number of electrode materials are required for the linear bus bar electrode, it is considered that the layout is not a linear shape. It is an island-shaped junction electrode.

[Advanced technical documents] [Patent Document]

[Patent Document 1] Patent No. 4284368

However, in recent years, the thickness of silicon substrates used in solar cells has decreased year by year, and it is expected that they will continue to decrease in the future. Since the solar cell module manufacturing step may cause bending due to the difference between the thermal expansion coefficients of the lead and the solar cell unit, it is necessary to reduce the bending in the module manufacturing step. Therefore, as this bending occurs, the thinner the thickness of the silicon substrate is, the more remarkable it is.

The present invention was made in view of the above, and an object thereof is to obtain a solar battery cell that can suppress bending of the solar battery cell caused by wire bonding to the solar battery cell.

In order to solve the above-mentioned problems and achieve the object, the present invention includes a semiconductor substrate having a pn junction; a light-receiving surface bus electrode extending in the first direction on the light-receiving surface side of the semiconductor substrate; and a plurality of back connection electrodes facing the semiconductor The back side of the substrate opposite to the light-receiving surface is dispersedly arranged along the first direction. The light-receiving surface bus electrode is provided with a plurality of through holes penetrating in the thickness direction of the light-receiving surface bus electrode along the first direction, and the back surface is connected to the electrode and is arranged in the thickness direction of the semiconductor substrate relative to the light-receiving surface bus electrode except for a plurality of The location outside the through hole.

According to the solar battery cell of the present invention, it is possible to suppress the bending of the solar battery cell caused by wire bonding to the solar battery cell.

1.11‧‧‧Semiconductor substrate

2‧‧‧n-type impurity diffusion layer

3‧‧‧Anti-reflection film

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

10, 110, 210 ‧‧‧ solar battery unit

11A‧‧‧Receiving surface

11B‧‧‧Back

12, 112, 212‧‧‧ Receiver electrode

12a‧‧‧Silver electrode paste

12B, 112B, 212B

12Ba‧‧‧The side of the light receiving surface bus electrode

12G‧‧‧Receiving grid electrode

13, 113, 213‧‧‧ Back electrode

13A‧‧‧Back collector electrode

13B, 113B, 213B

1131~1138‧‧‧ Connect electrode on the back

13a‧‧‧Aluminum electrode paste

13b‧‧‧Silver electrode paste

20‧‧‧Lead

20a‧‧‧Bend

20b‧‧‧Lead in lateral direction

25‧‧‧Horizontal

26‧‧‧Output lead

31‧‧‧Receiving Department

32‧‧‧Back Protection

33‧‧‧Light-receiving side sealing material

34‧‧‧Back side sealing material

40‧‧‧Frame

50‧‧‧Solar battery string

60‧‧‧Through hole

61, 611~618‧‧‧ Region 1

62‧‧‧ Region 2

63‧‧‧Connect

63a‧‧‧The outer side of the connecting part

70‧‧‧Solar battery array

100‧‧‧solar battery module

101‧‧‧ one end

102‧‧‧The other end

A1~A8‧‧‧ Length of the first area

B1~B9‧‧‧Distance

C1~C8‧‧‧ Length of connecting electrode on the back

D1~D9‧‧‧Distance

[Figure 1] is a perspective view of the solar cell module of the first embodiment of the present invention seen from the light receiving surface side; [Figure 2] is an exploded perspective view of the solar cell module of the first embodiment of the present invention seen from the light receiving surface side [FIG. 3] is a cross-sectional view of the main part of the solar cell module of the first embodiment of the present invention; [FIG. 4] is a perspective view of the solar cell array of the first embodiment of the present invention seen from the back side; [第5 [Figure 6] is a perspective view of the solar cell string of the first embodiment of the present invention seen from the light-receiving surface side; [Figure 6] is a perspective view of the solar cell string of the first embodiment of the present invention seen from the back side; [Figure 7] The plan view of the solar cell unit of the first embodiment of the present invention seen from the light receiving surface side; [Figure 8] is the plan view of the solar cell unit of the first embodiment of the present invention seen from the back side facing the side opposite to the light receiving surface side; [Figure 9] is a cross-sectional view showing the configuration of a solar cell unit according to the first embodiment of the present invention, and is a cross-sectional view of the main part in the line IX-IX in FIG. 7; [FIG. 10] shows the first of the present invention The cross-sectional view of the structure of the solar battery cell of the embodiment is a cross-sectional view of the main part taken along the line XX in FIG. 7; [FIG. 11] is a bus bar electrode showing the light-receiving surface of the solar battery cell of the first embodiment of the present invention [Fig. 12] is a plan view showing the state of welding leads on the light-receiving surface bus electrode of the solar cell unit according to the first embodiment of the present invention; [FIG. 13] is a solar showing the first embodiment of the present invention. The cross-sectional view of the structure of the battery cell is a cross-sectional view of the main part in the line XIII-XIII in FIG. 12; [FIG. 14] is a cross-sectional view showing the structure of the solar battery cell according to the first embodiment of the present invention. 12 is a cross-sectional view of the main part of the XIV-XIV line in FIG. 12; [Figure 15] is a procedure illustrating the manufacturing steps of the solar cell unit of the first embodiment of the present invention; [Figure 16] is a first embodiment of the present invention. [Fig. 17] is a cross-sectional view of the main part of the manufacturing process of the solar cell unit of the first embodiment of the present invention; [Fig. 18] is a cross-sectional view of the main part of the manufacturing process of the solar cell unit of the first embodiment of the present invention; [Fig. 19] is a cross-sectional view of the main part of the manufacturing process of the solar cell unit of the first embodiment of the present invention; [Fig. 20] is a cross-sectional view of the main part of the manufacturing process of the solar cell unit of the first embodiment of the present invention; [Fig. 21] is a cross-sectional view of the main part of the manufacturing process of the solar cell according to the first embodiment of the present invention; [Fig. 21] A cross-sectional view of main parts showing the manufacturing steps of the solar cell unit according to the first embodiment of the present invention; [Figure 23] is a procedure for explaining the manufacturing method of the solar cell module according to the first embodiment of the present invention; [Figure 24] A plan view of a solar cell unit according to a second embodiment of the present invention seen from the light-receiving surface side; [Figure 25] is a second embodiment of the present invention seen from the back side facing the side opposite to the light-receiving surface side [Figure 26] is a cross-sectional view of main parts showing the configuration of a solar cell module according to a second embodiment of the present invention; [Figure 27] is a solar cell showing a second embodiment of the present invention [Figure 28] is a diagram showing the conditions of the connection of the back electrode of the solar cell unit of the second embodiment of the present invention; [Figure 29] is the solar system of the third embodiment of the present invention. [Figure 30] is a diagram showing the configuration conditions of the light-receiving surface electrode of the solar cell unit of the third embodiment of the present invention; and [Figure 31] is a solar cell showing the third embodiment of the present invention. Conditional diagram of the connection of electrodes on the back of the unit.

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. In addition, this invention is not limited by this embodiment.

[First embodiment]

Fig. 1 is a perspective view of the solar cell module 100 according to the first embodiment of the present invention as viewed from the light-receiving surface side. Fig. 2 is an exploded perspective view of the solar cell module 100 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 part of the solar cell module 100 according to the first embodiment of the present invention. In the solar cell 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 with 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 surface side opposite to the light-receiving surface is covered with the back side sealing material 34 and the back surface protection portion 32, and the periphery of the outer peripheral edge portion is surrounded by a frame 40 for reinforcement.

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 cell string 50 of the first embodiment of the present invention seen from the light-receiving surface side. Fig. 6 is a perspective view of the solar cell 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 such that a plurality of solar cell strings 50 are electrically or mechanically connected in series or in parallel with the horizontal lead 25 and the output lead 26.

In addition, as shown in FIGS. 3 to 6, the solar battery string 50 is configured such that a plurality of solar battery cells 10 having a quadrangular shape are arranged adjacent to each other by electrically and mechanically connecting leads 20 in series. As shown in FIGS. 3 to 6, the plural solar battery cells 10 are connected in series by the lead 20 in the X direction of the drawing in the first direction. The first direction is the connection direction of the plural solar battery cells 10 connected by the lead 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 two adjacent solar battery cells 10 and the other of the two adjacent solar battery cells 10 The electrodes formed on the back side of the second main surface of the cell 10 are alternately connected by leads 20. Then, one end of the lead 20 is welded to the back surface connection electrode 13B formed on the back surface side of the solar cell 10 described later, and the other end side is welded to the light receiving surface bus electrode 12B formed on the light receiving surface side of the adjacent solar cell 10. That is, the lead 20 connected to the light-receiving surface bus electrode 12B formed on the light-receiving surface side of the solar battery cell 10 is connected in series to a plurality of solar battery cells by connecting to the back connection electrode 13B formed on the back surface side of the adjacent solar battery cell 10 10.

Fig. 7 is a plan view of the solar battery cell 10 according to the first embodiment of the present invention seen from the light-receiving surface side. Fig. 8 is a plan view of the solar battery cell 10 according to the first embodiment of the present invention as viewed 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 the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view of the main part in the line IX-IX in FIG. 7. FIG. 10 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view of the main part of the X-X line in FIG. 7. In FIGS. 9 and 10, the lead 20 connected to the solar battery cell 10 is also shown.

The solar cell 10, including the semiconductor substrate 11, has a quadrangular shape in which an impurity diffusion layer is formed to constitute a pn junction. That is, in the solar battery cell 10, the n-type impurity diffusion layer 2 of the impurity diffusion layer that diffuses the n-type impurity by phosphorus diffusion is formed on the light-receiving surface side of the surface of the semiconductor substrate 1 made of p-type silicon of the first conductivity type. 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, that is, a rectangular shape in the plane direction of the semiconductor substrate 11.

In the solar battery cell 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 improve the light collection rate, texture etching is used to form an uneven shape. That is, fine irregularities are formed on the surface of the semiconductor substrate 11 as a texture structure. The minute irregularities increase the area of the light-receiving surface 11A that absorbs light from the outside, suppresses the reflectance of the light-receiving surface 11A, and becomes a structure that turns off light. In Figs. 9 and 10, for the sake of convenience, the illustration of minute irregularities is omitted. In addition, in the solar battery cell 10, an antireflection film 3 made of a silicon nitride film is formed on the first main surface of the semiconductor substrate 11, that is, on the light receiving surface 11A side of the semiconductor substrate.

In the semiconductor substrate 1, a p-type single crystal silicon substrate or a p-type polycrystalline silicon substrate can be used. In addition, the semiconductor substrate 1 is not limited thereto, and an n-type single-crystal silicon substrate, an n-type polycrystalline silicon substrate, or another silicon-based substrate may be used. In addition, the anti-reflection film 3 may use a nitrogen oxide film.

In the solar battery cell 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-mentioned light-receiving surface electrode 12 is provided to be 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 light-receiving surface gate electrodes 12G are arranged in line in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. The light-receiving surface grid electrode 12G is an electrode for collecting photocurrent generated by the solar cell 10 from the light-receiving surface 11A side of the semiconductor substrate 11. The light-receiving surface grid electrode 12G is electrically connected to the n-type impurity diffusion layer 2 at the bottom surface portion. The light-receiving surface grid electrode 12G is a paste electrode formed by applying a conductive paste material having metal particles in a desired range and firing it.

In addition, the light-receiving surface bus electrode 12B that communicates with the light-receiving surface gate electrode 12G is provided to intersect 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 electrodes 12B are arranged in four rows linearly over the entire length of the solar battery cells 10 along the first direction of the connection direction of the solar battery cells 10. That is, the longitudinal direction of the light-receiving surface bus bar electrode 12B is the connection direction of the plurality of solar battery cells 10 connected by the lead 20 in the same direction as the first direction described above. In addition, the arrangement direction of the light-receiving surface bus electrodes 12B is formed on the surface of the semiconductor substrate 11 in the same direction as the second direction perpendicular to the first direction. The light-receiving surface bus electrode 12B is provided to be connected to all the light-receiving surface grid electrodes 12G. The light-receiving surface bus electrode 12B is electrically connected to the n-type impurity diffusion layer 2 on the bottom surface portion. For convenience, Figs. 1, 2, 4 and 5 show a case where two rows of light-receiving surface bus electrodes 12B are provided.

The light-receiving surface bus bar electrode 12B is provided to collect the photocurrent collected by the light-receiving surface grid electrode 12G, and an electrode for electrically bonding with the lead 20. The light-receiving surface bus electrode 12B is a paste electrode formed by applying a conductive paste material having metal particles in a desired range and firing it. For the light-receiving surface bus bar electrode 12B, when the solar cell module 100 is manufactured using the solar cell 10, as shown in FIGS. 9 and 10, the lead 20 is welded. In FIGS. 9 and 10, only the light-receiving surface bus electrode 12B of the light-receiving surface electrode 12 is shown.

FIG. 11 is a plan view showing the shape of the light-receiving surface bus electrode 12B of the solar battery cell 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 through the plurality of through holes 60 in the thickness direction of the light-receiving surface bus bar electrode 12B in the in-plane direction of the solar cell 10, that is, the surface of the semiconductor substrate 11 A stepping stone is provided along the first direction in the inner direction. FIG. 7 shows, for example, a case where seven through holes 60 are provided in the light-receiving surface bus electrode 12B along the first direction.

That is, 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 provided in the extension direction of the light-receiving surface bus bar electrode 12B, that is, in the first direction. In the second region 62, the connecting portion 63 provided in the outer edge region in the lateral direction of the light-receiving surface bus electrode 12B is connected between adjacent first regions 61 in the extending direction of the light-receiving surface bus electrode 12B. Therefore, all the first regions 61 and the second regions 62 in one light-receiving surface bus electrode 12B are electrically connected.

In addition, the lead 20 is welded to the light-receiving surface bus bar electrode 12B, mainly through the welding of the first region 61 and the lead 20. Therefore, the welding area of the light-receiving surface bus electrode 12B and the lead 20 approximates the welding area of the first region 61 and the lead 20.

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

In addition, the size and position of the through hole 60 only need to match the size and position of the back connection electrode 13B described later. The size and position of the back 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 electrode 12B increases due to the provision of a plurality of through holes 60 in the light-receiving surface bus electrode 12B, which can be suppressed by increasing the height of the light-receiving surface bus electrode 12B.

Also, the light-receiving surface bus electrode 12B has the same width in the longitudinal direction as shown in FIG. 11, the width in the first region 61 is equal to the width in the second region 62, and both ends in the second direction , Forming a straight line parallel to the first direction. The second direction corresponds to the Y direction in Figure 11. Therefore, when manufacturing the solar cell module 100 to the electrode connection lead 20 of the solar battery cell 10, the lead 20 having the same width as the light-receiving surface bus bar electrode 12B overlaps with the light-receiving surface bus bar electrode 12B in the position in the second direction In the state on the light-receiving surface bus bar electrode 12B, it is welded to the light-receiving surface bus bar electrode 12B.

FIG. 12 is a plan view showing a state where the lead wire 20 is welded to the light-receiving surface bus 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 the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view of main parts taken along the line XIII-XIII in FIG. 12. FIG. 14 is a cross-sectional view showing the configuration of the solar battery cell 10 according to the first embodiment of the present invention, and is a cross-sectional view of the main part in the line XIV-XIV in FIG. 12.

As shown in FIGS. 13 and 14, the lead 20 is parallel to the light-receiving surface bus electrode 12B, and is arranged on the light-receiving surface bus electrode 12B in a position overlapping the light-receiving surface bus electrode 12B in the lateral direction of the lead 20. , Welded to the upper surface of the light-receiving surface bus electrode 12B. That is, to the light-receiving surface bus bar electrode 12B, in the second direction, the lead 20 is welded in a state where the lead is overlapped on the side surface 20 b in the lateral direction on the side surface 12Ba of the light-receiving surface bus electrode in the lateral direction. The longitudinal direction of the lead 20 in the state of being welded to the light-receiving surface bus bar electrode 12B is the same direction as the long-side direction of the light-receiving surface bus bar electrode 12B, and the same direction as the first direction described above, that is, the X direction. The lateral direction of the lead 20 in the state of being welded to the light-receiving surface bus electrode 12B is the same direction as the width of the light-receiving surface bus electrode 12B and the same direction as the second direction described above, that is, the Y direction.

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

In the plurality of second regions 62 where the through holes 60 are provided, the lead 20 is welded to the light-receiving surface bus bar electrode 12B, and the lead portion 20 is welded to the lead portion 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. It is performed at both ends of the lead 20 in the lateral direction.

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 grid electrode 12G is 30 μm (micrometer) or more and 80 μm (micrometer) or less. The width of the connecting portion 63 is 60 μm (micrometer) or more and 160 μm (micrometer) or less. The width of the connection portion 63 is about 1/15 or more and 1/5 or less of the width of the light-receiving surface bus electrode 12B. When the width of the light-receiving surface bus bar electrode 12B is within the above range, when the amount of electrode material used in the light-receiving surface bus bar electrode 12B is reduced and the resistance of the light-receiving surface bus bar electrode 12B provided with the through-hole 60 increases, etc., the connection portion The width of 63 is preferably about 1/10 of the width of the light receiving surface bus electrode 12B.

In addition, when the width of the light-receiving surface grid electrode 12G is within the above range, the width of the connecting portion 63 is about twice the width of the light-receiving surface grid electrode 12G. The width of the connection portion 63 may be considered when the amount of electrode material used in the light-receiving bus bar electrode 12B is reduced and the resistance of the light-receiving bus bar electrode 12B provided with the through-hole 60 is increased. The height is preferably about twice the width of the light-receiving gate electrode 12G.

When the width of the light-receiving surface grid electrode 12G is thinned, the number of light-receiving surface grid electrodes 12G increases as much as the width of the light-receiving surface grid electrode 12G is increased, and the light receiving amount and the electrode resistance loss are in the same state, and the carrier arrives As far as the light-receiving surface gate electrode 12G, the distance flowing through the n-type impurity diffusion layer 2 becomes shorter, and the resistance loss in the n-type impurity diffusion layer 2 decreases. Therefore, the thinning of the width of the light-receiving gate electrode 12G is desirable from the viewpoint of resistance loss. However, the width of the light-receiving surface grid electrode 12G is selected to be the lower limit width in accordance with manufacturing limitations. In particular, when the light-receiving surface grid electrode 12G is formed by inexpensive screen printing, the lower limit width of the light-receiving surface grid electrode 12G that can be formed during thinning is limited to 30 μm (micrometer) or more and 100 μm (micrometer) or less.

Regarding the width of the connecting portion 63, from the viewpoint of reducing the amount of electrode material used, it is preferable to make the line thin. However, the lower limit width is selected in accordance with manufacturing limitations and characteristics limitations of the solar cell 10. The light-receiving surface grid electrode 12G and the connecting portion 63, together with the light-receiving surface bus electrode 12B, use a single printing mask to simultaneously perform screen printing. Therefore, the height of the light-receiving surface grid electrode 12G printed by screen printing, the height of the connection portion 63, and the height of the light-receiving surface bus bar electrode 12B have the same height. When the height of the light-receiving surface grid electrode 12G is the same as the height of the connecting portion 63, the current flowing into the connecting portion 63 is a component of several pieces of the light-receiving surface grid electrode 12G, that is, 2, 3 to 5, 6, and is connected. The width of the portion 63 is preferably about twice that of the light-receiving surface grid electrode 12G.

As described above, the light-receiving surface bus electrode 12B is formed in a parallel linear shape at the both ends in the second direction toward the first direction. That is, the light-receiving surface bus electrode 12B is formed in a linear shape parallel to the first direction on the outer side surface 63a of the two connecting portions facing in the second direction. Therefore, when manufacturing the solar cell module 100 to the electrode connecting lead 20 of the solar cell 10, the side surface 12Ba of the light-receiving surface bus bar electrode 12B in the second direction and the light-receiving surface bus bar electrode in the lateral direction in the second direction, The lead 20 is welded in a state where the lateral sides 20b of the lead in the lateral direction are overlapped. That is, the position of the side surface 12Ba of the light-receiving surface bus electrode and the position of the side surface 20b in the lateral direction of the lead are 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 20 is welded to the light-receiving surface bus electrode 12B, the connecting portion 63 does not protrude outward from the first region 61. That is, in a state where the lead wire 20 is soldered to the light-receiving surface bus 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 having the connection portion 63 from being exposed from the lead wire 20 without being soldered to the lower surface of the lead wire 20. The amount of light received decreases. That is, the light-receiving surface bus electrode 12B exposed from the lead 20 is prevented from reducing the light-receiving area due to the formation of unnecessary shadows on the light-receiving surface 11A of the semiconductor substrate 11, thereby preventing the photoelectric conversion efficiency from decreasing.

For example, when the connection portion 63 is provided to protrude outward from the first region 61 in the second direction, how much area of the connection portion 63 is exposed from the lead 20 connected to the light-receiving bus bar electrode 12B, and the amount of light received by the solar cell 10 How much it will fall, it becomes the cause of the decline in photoelectric conversion efficiency.

In addition, the light-receiving surface bus bar electrodes 12B are formed in a linear shape parallel to the first direction at both ends in the second direction, and the connecting portion 63 is connected to the first direction with the shortest distance in the in-plane direction of the semiconductor substrate 11 In the adjacent first area 61. Therefore, the photocurrent accumulated in the light-receiving surface bus electrode 12B can suppress the resistance loss caused by flowing in the second region 62 of the connecting portion 63 narrower than the first region 61 in width.

In addition, when the light-receiving surface grid electrode 12G and the lead 20 are welded, stress when welding to the light-receiving surface grid electrode 12G is concentrated, and the light-receiving surface grid electrode 12G may be disconnected. In the solar battery cell 10, the connection portion 63 and the lead 20 are welded to the second region 62, and the light-receiving surface grid electrode 12G and the lead 20 are not welded. Therefore, the solar battery cell 10 can suppress disconnection of the light-receiving surface grid electrode 12G caused by welding of the light-receiving surface grid electrode 12G and the lead 20.

In addition, when manufacturing the solar battery module 100 by connecting the lead 20 to the electrode of the solar battery unit 10, the solar battery unit 10 can use a general lead 20 having the same width throughout the longitudinal direction, without using a special shape of the solar battery unit 10 Lead 20.

For the solar cell module 100, a general lead 20 having the same width is formed throughout the longitudinal direction. As a result, when the lead 20 is welded to the solar cell 10, the positions of the solar cell 10 and the lead 20 in the longitudinal direction of the light-receiving bus electrode 12B and the lead 20 determine the position of the light-receiving bus electrode 12B and the lead 20 The decision becomes unnecessary. Therefore, in the solar cell module 100, the light-receiving surface bus electrode 12B and the lead 20 can be welded at any position in the longitudinal direction of the light-receiving surface bus electrode 12B and the lead 20, and the manufacturing is easy.

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

The rear collector electrode 13A is an electrode provided for forming the BSF layer 4 and for collecting photocurrent generated by the solar battery cell 10 from the rear surface 11B side of the semiconductor substrate 11, covering substantially the entire rear surface of the solar battery cell 10. The rear collector electrode 13A is a paste electrode formed by applying a conductive paste of metal particles containing electrode material Al to a desired range and firing it.

In addition, the back surface is connected to the electrode 13B, and the photocurrent collected by the back surface collector electrode 13A is taken out to the outside, and an electrode for contact with the external electrode is provided. That is, the back connection electrode 13B is provided with an electrode for bonding with the lead 20. The back connection electrode 13B is the same as the light-receiving surface bus electrode 12B, and is provided along the first direction which is the connection direction of the solar battery cells 10. The back connection electrode 13B is a paste electrode formed by applying a conductive paste of metal particles containing the electrode material Ag to a desired range and firing it.

The back surface connection electrode 13B sandwiches the semiconductor substrate 11 and is arranged at a position opposite to the light receiving surface bus electrode 12B. In addition, as shown in FIG. 8, the back connection electrodes 13B are distributed along the first direction, which is the connection direction of the solar battery cells 10, in a stepping stone shape and arranged in four rows over the substantially entire length of the solar battery cells 10. By forming the back connection electrode 13B into a stepping stone shape, the amount of silver used can be suppressed, and the manufacturing cost can be suppressed.

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

Therefore, in one solar battery cell 10, the lead 20 soldered to the light-receiving surface bus 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 battery cell 10, that is, the semiconductor The substrate 11 is soldered to the solar cell 10 at the same position in the in-plane direction. That is, in one solar battery cell 10, the lead 20 soldered 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 soldered at positions facing each other in the thickness direction of the semiconductor substrate 11.

Therefore, in the in-plane direction of the solar battery cell 10, since the area of the first region 61 of the light-receiving surface bus electrode 12B and the area of the back connecting electrode 13B are substantially the same, the welding area of the light-receiving surface bus electrode 12B and the lead 20 and 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 a plurality of solar battery cells 10, the connection portion between the lead wire 20 and the light receiving surface bus electrode 12B when the lead wire 20 is welded to the solar battery cell 10, and the lead wire 20 and The internal stress generated in the connection portion of the back connection electrode 13B almost cancels out.

When manufacturing the solar cell module 100 by connecting the lead 20 to the electrode of the solar cell 10, as shown in FIGS. 9 and 10, the lead 20 is soldered to the light-receiving bus bar electrode 12B and the back connection electrode 13B. When the light-receiving surface bus bar electrode 12B does not have the through-hole 60 and the back surface connection electrode 13B is dispersed in a stepping stone shape, the area of the light-receiving surface bus bar electrode 12B in the surface of the semiconductor substrate 11 and the back surface in the surface of the semiconductor substrate 11 The difference between the areas of the connection electrodes 13B becomes larger. Therefore, the internal stress generated in the connection between the lead 20 and the light-receiving surface bus electrode 12B due to the welding of the lead 20 when manufacturing the solar cell module 100 and the internal stress generated in the connection between the lead 20 and the back connection electrode 13B 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 battery cell 10 and the light-receiving surface bus electrode 12B and the connection portion of the back-side lead 20 of the solar battery cell 10 and the back connection electrode 13B The internal stress generated in the process cannot be balanced, and the difference in internal stress becomes the main cause of the bending of the solar cell 10.

As a result, a bend due to a difference in the coefficient of thermal expansion of the lead 20 made of metal and the silicon of the semiconductor substrate 11 occurs. In general, the thermal expansion coefficient of the metal constituting the lead 20 is larger than that of silicon. Therefore, when the light-receiving surface bus bar electrode 12B does not have the through hole 60 and the back connecting electrode 13B is dispersedly 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 inner back connection electrode 13B is large, the solar battery cell 10 bends convexly toward the back side after welding.

On the other hand, in the solar battery cell 10, the first region 61 of the light-receiving surface bus bar electrode 12B and the back connecting electrode 13B are arranged at corresponding positions in the surface of the semiconductor substrate 11, and in the in-plane direction of the solar battery cell 10 Since the area of the first region 61 of the light-receiving surface bus bar electrode 12B and the area of the back connecting electrode 13B are substantially the same, the welding area of the light-receiving bus bar electrode 12B and the lead 20 and the welding area of the back connecting electrode 13B and the lead 20 become To be roughly equal. As a result, the fixed position of the soldered light-receiving bus bar electrode 12B and the lead 20 and the fixed position of the soldered back connection electrode 13B and the lead 20 become the same position on the surface of the semiconductor substrate 11, and the solar battery cell 10 can be The above-mentioned internal stress is balanced between the light-receiving surface side and the back surface side of the solar battery cell 10. Therefore, the solar battery cell 10 can suppress bending of the solar battery cell 10 caused by welding the lead wire 20 to the solar battery cell 10 when the solar battery module 100 is manufactured. Therefore, the solar battery cell 10 can reduce the breakage rate of the solar battery cell 10 due to the bending of the solar battery cell 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 and the area of the back connection electrode 13B in the in-plane direction of the solar battery cell 10 are accurately formed to the same area, the light-receiving surface side of the solar battery cell 10 can be accurately obtained The balance of the internal stress on the back side.

In addition, in the solar battery cell 10, as described above, since the bending of the solar battery cell 10 when manufacturing the solar battery module 100 can be suppressed, it is possible to cope with the thinning of the semiconductor substrate 11 and use a thinner semiconductor substrate 11 to reduce the cost of the semiconductor substrate 11 , Can correspond to the realization of cheap solar cells 10.

In addition, the configuration of the solar cell 10 of the first embodiment described above is an example, and the structure of the large-scale solar cell is not limited to the above description.

In addition, in FIGS. 7 and 8, as a representative example, the case where there are four light-receiving surface bus electrodes 12B and the back connection electrodes 13B is shown, but the number of the light-receiving surface bus electrodes 12B and the back connection electrodes 13B is not limited to The above description.

Next, the 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 flowchart illustrating a procedure of the manufacturing steps of the solar battery cell 10 according to the first embodiment of the present invention. 16 to 22 are cross-sectional views of main parts showing the manufacturing steps of the solar battery cell 10 according to the first embodiment of the present invention. Also, Figures 20 to 22 show the figures corresponding to Figure 9.

First, as the semiconductor substrate 1, as shown in FIG. 16, for example, a square p-type single crystal silicon substrate that is most frequently used for solar cells for civilian use is prepared. Here, the thickness and size of the semiconductor substrate 1 are not particularly limited, but 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 a silicon ingot formed by cooling and solidifying molten silicon is cut by a wire saw, the semiconductor substrate 1 is manufactured, and the damage during slicing remains on the surface. Therefore, first, as well as removing the damaged layer, the surface is etched in an acid solution or a heated alkaline solution by immersing the semiconductor substrate 1 to remove the damaged region that occurs near the surface of the semiconductor substrate 1 when the semiconductor substrate 1 is cut out. As an example of the alkali solution, a sodium hydroxide aqueous solution is mentioned.

Next, in step S10, as the texture structure on the surface of the semiconductor substrate 1 on the light-receiving surface side, minute irregularities (not shown) are formed. The minute irregularities are formed by, for example, 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 formed with fine irregularities on the surface as a texture structure is put into a thermal diffusion furnace, heated in an air of phosphorus (P) of n-type impurities, and a 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, an n-type impurity diffusion layer 2 is formed on the surface layer of the semiconductor substrate 1 to form a pn junction. With this, the semiconductor substrate 11 constituting the 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 heated in a mixed air of phosphorus oxychloride (POCl ₃ ) gas and oxygen 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 phosphorus oxychloride gas, air temperature, and heating time. Here, on the surface after the formation of the n-type impurity diffusion layer 2, a phosphor glass layer (not shown) of a mixture of a silicon oxide film containing phosphor oxide as a main component and phosphor oxide is formed. Therefore, the phosphorous glass layer on the surface of the n-type impurity diffusion layer 2 is removed with a chemical such as a hydrofluoric acid aqueous solution.

Next, in step S30, a pn separation step of electrically insulating the back electrode 13 of the p-type electrode and the light-receiving surface electrode 12 of the n-type electrode is performed to remove the n-type impurity diffusion layer 2 at the end of the semiconductor substrate 11 as shown in FIG. . Since the n-type impurity diffusion layer 2 is similarly formed 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 electrode 13 and the light-receiving surface electrode 12 are formed on the semiconductor substrate 11, the back 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 plasma etching end face etching or laser processing melt separation.

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, in order to improve surface protection and improve photoelectric conversion efficiency, as shown in FIG. 19, a silicon nitride (SiN) film is formed as Anti-reflection film 3. For the formation of the anti-reflection film 3, for example, using a plasma chemical vapor deposition (Plasma-Enhanced Chemical Vapor Deposition: PECVD) method, a mixed gas of silane and ammonia is used to form a silicon nitride film as the anti-reflection film 3. The film thickness and refractive index of the anti-reflection film 3 are set to the values that most suppress light reflection.

Next, electrodes are 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. That is, as shown in FIG. 20, the silver electrode paste 12a containing the electrode material paste of silver and glass frit is printed as the light-receiving surface electrode 12 on the anti-reflection film 3 on the light-receiving surface side of the semiconductor substrate 11 shape. Here, the silver electrode paste 12a is printed in the shape of the light-receiving surface bus electrode 12B including a plurality of first regions 61 and a plurality of second regions 62 as shown in FIGS. 7 and 11. After that, the silver electrode paste 12a is dried.

Next, in step S60, the back electrode 13 is printed on the back surface of the semiconductor substrate 11 by screen printing. It does not matter which of the printing of the back collector electrode 13A and the printing of the back connection electrode 13B is performed first, but the case where the back 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 connection electrode 13B. The silver electrode paste 13b is printed on the light-receiving surface of the semiconductor substrate 11 at a position corresponding to the position where the first region 61 of the light-receiving bus 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 glass frit, is printed into the shape of the back collector electrode 13A. The aluminum electrode paste 13a is printed on the surface of the back surface of the semiconductor substrate 11, the printed area of the back connection electrode 13B, and the entire back surface except for a part of the outer edge area are printed using a printing mask having an opening pattern. Also, 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.

Then, in step S70, the electrodes subjected to the firing process of the printing paste are fired, and by firing the electrode paste printed on the semiconductor substrate 11, as shown in FIG. 22, the light-receiving surface grid as the light-receiving surface electrode 12 is obtained The electrode 12G and the light-receiving surface bus electrode 12B are connected to the back surface collector electrode 13A and the back surface connection electrode 13B as the back electrode 13. Firing is carried out using an infrared heating furnace at about 750°C to 900°C in atmospheric air. The firing temperature is selected in consideration of the structure of the solar cell 10 and the type of electrode paste.

According to the firing, on the light-receiving surface side of the semiconductor substrate 11, the anti-reflection film 3 of the silver insulating film penetrating through the light-receiving surface electrode 12 is fired to electrically connect the n-type impurity diffusion layer 2 and the light-receiving surface electrode 12. Therefore, the n-type impurity diffusion layer 2 can obtain good resistive bonding with the light-receiving surface electrode 12.

On the other hand, on the back side of the semiconductor substrate 11, the aluminum electrode paste 13 a and the silver electrode paste 13 b are fired to form the back collector electrode 13A and the back connection electrode 13B, and at the same time, an alloy part (not shown) composed of aluminum and silver is formed. .

When forming the back surface collector electrode 13A, the aluminum electrode paste 13a also reacts with the p-type single crystal silicon on the back surface of the semiconductor substrate 11 and undergoes post-reaction curing to form a p+ layer BSF layer 4 containing aluminum. That is, in the n-type impurity diffusion layer 2 formed on the back surface 11B side of the semiconductor substrate 11, the area immediately below the back surface collector electrode 13A is converted into the BSF layer 4 by aluminum diffusion. In addition, in the n-type impurity diffusion layer 2 formed on the back side of the semiconductor substrate 11, in a region other than directly below the back collector electrode 13A, diffused aluminum becomes a p-type region.

Next, a method of manufacturing the solar cell module 100 including the solar cell unit 10 of the first embodiment will be described. FIG. 23 is a flowchart showing the procedure of the manufacturing method of the solar cell module 100 according to the first embodiment of the present invention.

First, in step S110, the bus bar electrode 12B of one solar cell 10 is soldered to the light-receiving surface bus bar electrode 12B of the other solar cell 10 and the back electrode 13B of the other solar cell 10 is joined to electrically connect a plurality of solar cells with the lead 20 10. The solar cell string 50 is formed.

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

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

Thereafter, the outer edge of the solar cell module 100 is held by the frame 40 over 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 electrode 12B. As a result, in the solar battery cell 10, the amount of electrode material used in the light-receiving surface bus electrode 12B can be reduced, and the manufacturing cost of the solar battery cell 10 can be reduced.

Furthermore, in the solar battery cell 10 of the first embodiment, the first region 61 of the light-receiving surface bus electrode 12B and the back connection electrode 13B are arranged at corresponding positions in the plane of the semiconductor substrate 11 with the semiconductor substrate 11 interposed therebetween. The semiconductor substrate 11 is opposed in the thickness direction. Thereby, the solar battery cell 10 can suppress the bending of the solar battery cell 10 caused by welding the lead 20 to the solar battery cell 10 when manufacturing the solar battery module 100, and can cause the solar battery cell 10 to bend when manufacturing the solar battery module 100. The breakage rate of the solar battery cell 10 is reduced.

In the solar battery cell 10 of the first embodiment, the light-receiving surface bus electrode 12B has the same width in the longitudinal direction, and both end portions in the second direction are linear parallel to the first direction. The width of the light-receiving surface bus bar electrode 12B and the width of the lead 20 connected to the light-receiving surface bus bar electrode 12B having the same width in the longitudinal direction form the same width. Therefore, when manufacturing the solar cell module 100, the positions of the side surfaces 12Ba of the light-receiving surface bus electrode 12B on both sides of the light-receiving surface bus electrode 12B in the second direction and the lateral direction of the two sides of the lead 20 in the second direction The position of the side surface 20b is 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 bus bar electrode and the position of the side surface 20b of the lead in the lateral direction are at the same position in the in-plane direction of the light-receiving surface 11A of the semiconductor substrate 11. Thereby, the solar battery cell 10 prevents the decrease in the amount of light received by the solar battery cell 10 due to 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, and can prevent the photoelectric conversion efficiency from decreasing .

In addition, the solar battery cell 10 can suppress the bending of the solar battery cell 10 when the solar battery module 100 is manufactured, and can use a thinner semiconductor substrate 11 to reduce the cost of the semiconductor substrate 11, and can correspond to the realization of the inexpensive solar battery cell 10.

Therefore, according to the solar battery cell 10 of the first embodiment, it is possible to suppress the bending of the solar battery cell due to the bonding wire to the solar battery cell.

[Second Embodiment]

Fig. 24 is a plan view of the solar battery cell 110 of the second embodiment of the present invention seen from the light-receiving surface side. Fig. 25 is a plan view of the solar battery cell 110 according to the second embodiment of the present invention as viewed from the back side opposite to the light receiving surface side. Fig. 26 is a cross-sectional view of a main part of the configuration of a solar cell module according to a second embodiment of the present invention. FIG. 26 is a diagram corresponding to FIG. 3, and is a cross-sectional view of a main part of a solar battery module of the second embodiment configured with solar battery cells 110. FIG. The cross-sectional view of the solar battery cell 110 in FIG. 26 is a cross-sectional view of the main part in the line XXIII-XXIII in FIG. 24. FIG. 27 is a diagram showing the configuration conditions 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 diagram showing the configuration conditions of the back connection electrode 113B of the solar battery cell 110 according to the second embodiment of the present invention.

The solar cell 110 of the second embodiment replaces the light-receiving surface electrode 12 composed of the light-receiving surface grid electrode 12G and the light-receiving surface bus electrode 12B, and includes a light-receiving surface composed of the light-receiving surface grid electrode 12G and the light-receiving surface bus electrode 112B. Electrode 112. In addition, the solar battery cell 110 includes a rear electrode 113 composed of a rear collector electrode 13A and a rear connection electrode 113B instead of the rear electrode 13 composed of a rear collector electrode 13A and a rear connection 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 rear electrode 113. Regarding the configuration of the solar battery cell 110 that is the same as that of the solar battery cell 10 of the first embodiment, the same symbols are attached, and detailed descriptions are omitted.

The arrangement of the light receiving surface bus electrode 112B is different from that of the light receiving surface bus electrode 12B. The rear connection electrode 113B is different from the rear connection electrode 13B in arrangement.

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

Here, the one end 101 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 arrangement side of the light-receiving surface bus bar electrode 112B by the lead 20, which corresponds to The left side of the solar battery unit 110. In the solar battery cell 110, the end of the light-receiving surface bus bar electrode 112B adjacent to the arrangement side of the solar battery cell 110 is connected by a lead 20, and is the end portion of the light-receiving surface side connected to each other.

In addition, 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 light-receiving surface bus bar electrode 112B on the undisposed side by the lead wire 20, corresponding to FIGS. 24 to 26 The right side of the solar cell unit 110. In the solar battery cell 110, the end of the adjacent solar battery cell 110 on the light-receiving surface bus electrode 112B on the non-arranged side is connected by a lead 20, and the end portion of the light-receiving surface side that is not connected to each other.

In addition, the length of the first region in the longitudinal direction of the light-receiving surface bus 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 A1 and the length of the first region 612 Is the length of the first area A2, the length of the first area 613 is the length of the first area A3, the length of the first area 614 is the length of the first area A4, the length of the first area 615 is the length of the first area A5, the length of the first area 616 Is the length of the first area A6, the length of the first area 617 is the length of the first area A7, and the length of the first area 618 is the length of the first area A8.

Further, in the first direction, the distance between the one end 101 of the solar battery cell 110 and the first region 611 is the distance B1, and 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 the distance B3, the distance between the first area 613 and the first area 614 is the distance B4, the distance between the first area 614 and the first area 615 is the distance B5, the first area 615 and the 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, the first region 618 to the sun The distance of the other end 102 of the battery cell 110 is the distance B9.

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

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

Here, in the above-mentioned first direction, the one end 101 side of the solar battery cell 110 is connected to the end portion side of the rear surface connection electrode 113B on the non-arranged side of the solar battery cell 110 by the lead 20. In the solar battery cell 110, the end of the back surface connection electrode 113B adjacent to the non-arranged side of the solar battery cell 110 is connected by the lead 20, and is the end portion of the back surface side that is not connected to each other.

In addition, in the first direction, the other end 102 side of the solar battery cell 110 is connected to the end portion side of the rear surface connection electrode 113B adjacent to the arrangement side of the solar battery cell 110 with a lead 20. In the solar battery cell 110, the end of the back surface connection electrode 113B adjacent to the arrangement side of the solar battery cell 110 is connected by a lead 20, and is the end portion of the back surface side connected to each other.

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

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

The semiconductor substrate 11 has, for example, a square shape with a side length of 156 mm. The first area length A1, the first area length A2, the first area length A3, the first area length A4, the first area length A5, the first area length A6, and the first area length A7 are, for example, 5 mm. The first area length A8 is longer than the first area length A1 to the first area 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.

Back connection electrode length C1, back connection electrode length C2, back connection electrode length C3, back connection electrode length C4, back connection electrode length C5, back connection electrode length C6, back connection electrode length C7, back connection electrode length C8, for example 5mm. The distance D9 is longer than the distance D1, and there is a relationship of distance D1<distance D9. For example, the distance D1=0.5mm and the distance D9=6.5mm. 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 battery cell 110, in the first direction, it is preferable to provide the light-receiving surface bus bar electrode 112B up to both ends of the solar battery cell 110. On the other hand, on the back side of the solar battery cell 110, particularly on the other end 102 side that becomes the lead connection side, in the first direction, it is preferable to increase the distance from the end surface of the solar battery cell 110 to the back connection electrode 113B.

The light-receiving surface side of the solar battery cell 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 battery cell 110, bending due to the difference in thermal expansion coefficient between aluminum and silicon occurs in the solar battery cell 110. In general, since the thermal expansion coefficient of aluminum is larger than that of silicon, after the heat treatment of electrode firing, the solar cell unit 110 undergoes a convex curvature on the light-receiving surface side.

Therefore, when the lead 20 is welded to the solar battery cell 110, since the light receiving surface is convex, stress between the solar battery cell 110 and the lead 20 peeling the lead 20 in the vertical direction of the light receiving surface of the solar battery cell 110 occurs. Therefore, this peeling stress becomes the largest at the end of the solar battery cell 110.

Here, on the light-receiving surface side of the solar battery cell 110, since the light-receiving surface bus electrode 112B is provided up to both ends of the semiconductor substrate 11 in the first direction, the light-receiving surface bus electrode on the end side of the solar battery cell 110 can be strengthened The bonding strength between 112B and the lead 20. That is, as described above, the light-receiving surface bus electrode 12G is formed until the distance B1 and the distance B9 form a position of 0.5 mm in the first direction. Thus, the light-receiving surface bus electrodes 112B are provided until both ends of the light-receiving surface bus electrodes 12G in the first direction, and the light-receiving surface bus electrodes 112B are provided until the positions of both ends of the semiconductor substrate 11 in the first direction. With this, the solar battery cell 110 can further strengthen the bonding strength between the light-receiving surface bus bar electrode 112B and the lead 20 on the end side. Therefore, since both ends of the light-receiving surface bus electrode 112B in the first direction are constituted by the first regions, the bonding strength between the light-receiving surface bus electrode 112B and the lead 20 on the end side can be enhanced. When both ends of the light-receiving surface bus bar electrode 112B in the first direction are constituted by the second region 62, since the end portion of the light-receiving surface bus bar electrode 112B is welded to the lead wire 20 only by the connecting portion 63, the bonding strength decreases.

In addition, in the solar battery cell 110, the semiconductor substrate 11 has a rectangular shape, and has an end portion of the solar battery cell 110 in the first direction, that is, a first end edge portion, and a sun on the side opposite to the first end edge portion in the first direction The end of the battery cell 110 is the second end side. Therefore, the distance between the back connecting electrode 113B adjacent to the second end side and the second end side is longer than the distance between the back connecting electrode 113B adjacent to the first end side and the first end side.

The solar battery cell 10 of the first embodiment described above 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 20, as shown in FIG. 3, the lead 20 continues to be arranged from the lower left to the upper right in the figure, connecting the configuration between adjacent solar battery cells 10, and for the third In the adjacent solar battery cells 10 shown in the figure, the lead wires 20 are continuously arranged from the upper left to the lower right in the drawing, and the configuration connecting the adjacent solar battery cells 10 is equivalent.

On the other hand, the solar battery cell 110 of the second embodiment has an asymmetric configuration with respect to the center position in the first direction in the first direction. Therefore, when the solar cells 110 are connected by the lead 20, as shown in FIG. 26, the leads 20 continue to be arranged from the lower left to the upper right in the figure, connecting the configuration between adjacent solar cells 110, and for the 26th In the adjacent solar battery cells 110 shown in the figure, the leads 20 are continuously arranged from the upper left to the lower right in the drawing, and the configuration connecting the adjacent solar battery cells 110 is not an equivalent configuration.

Here, the lead 20 continues to be arranged from the lower left to the upper right, and connects the structure between adjacent solar battery cells 10. In the solar battery cells 10 arranged on the left and right as shown in FIG. 3, the rear surface of the left solar battery cell 10 is connected The electrode 13B is connected to the light-receiving surface bus electrode 12B of the solar cell 10 on the right side by a lead 20. In addition, the lead wires 20 are continuously arranged from the upper left to the lower right, and are connected between adjacent solar battery cells 10. In the solar battery cells 10 arranged on the left and right, the light-receiving surface bus electrode 12B of the left solar battery cell 10 and the right side The back electrode 13B of the solar battery cell 10 is connected by a lead 20.

The back side of the solar battery cell 110 having the above configuration is connected to the back side of the solar battery cell 110 at the other end 102 side of the solar battery cell 110 at the end of the solar battery cell 110 connected to each other. The distance of the electrode 113B, that is, the distance D9 from the back connection electrode 1138 to the other end 102 of the solar cell 110 has the following effects.

As shown in FIG. 26, the solar battery module of the second embodiment connects a plurality of solar battery cells 110 with a lead 20, and connects the lead 20 to the other solar battery in a curved shape from the back side of one solar battery cell 110a The light-receiving surface side of the unit 110b. That is, in the solar battery module of the second embodiment, the second end of the solar battery cell 110 disposed on the left in FIG. 26 and the other solar battery cell 110 disposed on the right in FIG. 26 The first end sides are arranged to face each other, and one of the solar battery cells 110 is adjacent to the other of the solar battery cells 110 in the first direction. In addition, the solar battery module of the second embodiment includes a lead wire 20 that connects the back connection electrode 113B of one solar battery cell 110 and the light receiving surface bus electrode 112B of the other solar battery cell 110. Then, the lead 20 connects the back connection electrode 113B on the second end side in one solar cell 110 and the light-receiving surface bus electrode 112B on the first end side in the other solar cell 110.

Distance D1<distance D9, and since the lead 20 is arranged from the back side of the solar cell 110a to the light-receiving surface side of the solar cell 110b on the side, the length of the curved portion 20a of the curved lead 20 becomes longer due to the curved lead 20, The bending radius of the bent portion 20a becomes larger, and the stress concentration on the bent portion 20a of the lead 20 is reduced. In particular, although the solar cell module is expected to be designed for a life span of more than 10 years, it is caused by the difference in linear expansion coefficient between the light-receiving glass serving as the light-receiving surface protection portion 31 and the lead 20, and the bending portion of the lead 20 is cycled due to the temperature of the day and night. In 20a, repetitive stresses occur and disconnection occurs, which becomes the main cause of failure. Here, by increasing the bending radius of the bent portion 20a of the lead 20, the repetitive stress applied to the bent portion 20a can be reduced, and a solar cell module excellent in long-term reliability can be realized.

In the solar battery cell 110, the first region 61 other than the end side of the non-interconnecting side of the light receiving surface side, that is, the first region 61 other than the other end 102 side and the back surface connecting electrode 113B are preferably provided on the light receiving surface and the back surface The corresponding position in. That is, the first region 611 to the first region 617 are preferably provided at positions corresponding to the in-plane surfaces of the back connection electrode 1131 to the back connection electrode 1137 and the solar battery cell 110, respectively. With this, the fixed position of the light-receiving surface bus electrode 112B and the lead 20 and the fixed position of the back connection electrode 113B and the lead 20 by soldering are the same in the plane of the semiconductor substrate 11 except for the first region 618 and the back connection electrode 1138 s position. Thereby, the solar battery cell 110, like the above-mentioned solar battery cell 10, can suppress the bending of the solar battery cell 110 caused by welding the lead 20 to the solar battery cell 110 when manufacturing the solar battery module. Therefore, the solar battery cell 110 can reduce the damage rate of the solar battery cell 110 due to the bending of the solar battery cell 110 when the solar battery module is manufactured.

In the light-receiving surface bus electrode 112B, the interval between the adjacent first regions in the end portion in the first direction is preferably greater than the interval in the first direction including the interval between the adjacent first regions in the central portion in the first direction The distance between the adjacent first regions on the inner side of is short. That is, in the light-receiving surface bus 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 better 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 lead 20 is welded to the solar battery unit 110, the solar battery unit 110 has a convex shape on the light-receiving surface side, and the lead is peeled between the solar battery unit 110 and the lead 20 in the vertical direction of the light-receiving surface of the solar battery unit 110 The stress of 20 becomes the largest on the end side in the first direction. On the other hand, by making the length of the second region on the end side in the first direction shorter than the length of the second region on the inner side in the first direction, the light-receiving surface bus electrode on the end side in the first direction can be strengthened The bonding strength of 112B and the 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 connection electrode 1138, the fixed position of the light receiving surface bus electrode 112B and the lead 20 and the back connection electrode 113B and the lead 20 by welding The fixed position of is the same position in the plane of the semiconductor substrate 11. Therefore, the solar battery cell 110 can reduce the breakage rate of the solar battery cell 110 due to the bending of the solar battery cell 110 when the solar battery module is fabricated, similar to the above-described solar battery cell 10.

Furthermore, in the solar battery cell 110 of the second embodiment, the end portion of the solar battery cell 110 on the interconnecting side, that is, the other end 102 side of the solar battery cell 110, extends the end surface of the solar battery cell 110 to the rear surface The distance of the electrode 113B. Therefore, the length of the bent portion 20a that bends the lead 20 connecting the adjacent solar battery cells 110 into a curved shape becomes longer. Therefore, the concentration of stress on the bent portion 20a of the lead 20 can be reduced due to the difference in linear expansion coefficient between the light-receiving surface glass serving as the light-receiving surface protection portion 31 and the lead 20, etc., because the temperature cycle applied to the bend due to day and night can be reduced The repeated stress of the portion 20a can realize a solar cell module having excellent long-term reliability.

[Third Embodiment]

FIG. 29 is a cross-sectional view showing the structure 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 and along the longitudinal direction of the light-receiving surface electrode 212, and the illustration of the rear collector electrode 13A is omitted for easy understanding. FIG. 30 is a diagram showing the configuration conditions 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 diagram showing the configuration conditions of the back connection electrode 213B of the solar battery cell 210 according to the third embodiment of the present invention.

The solar cell 210 of the third embodiment includes a light-receiving surface electrode 212 instead of the light-receiving surface bus electrode 112B, and a light-receiving surface bus electrode 212B. In addition, the solar battery cell 210 of the third embodiment includes a back electrode 213 having a back connection electrode 213B instead of the back connection electrode 113B. The solar cell 210 has the same configuration as the solar cell 110 of the second embodiment except for the light-receiving surface electrode 212 and the back electrode 213. Regarding the configuration of the solar battery cell 210 that is the same as that of the solar battery cell 10 of the first embodiment or the solar battery cell 110 of the second embodiment, the same symbols are attached, and detailed descriptions are omitted.

The arrangement of the light receiving surface bus electrode 212B is different from that of the light receiving surface bus electrode 112B. The rear connection electrode 213B is different from the rear connection electrode 113B in arrangement.

The light-receiving surface bus electrode 212B is the same as the light-receiving surface bus electrode 112B, and four solar battery cells 210 are provided. In addition, in each light-receiving surface bus electrode 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 in the same manner as the light-receiving surface bus electrode 112B. , The first area 616, the first area 617, the first area 618. The back connection electrodes 213B are arranged in four steps along the first direction, and are arranged at intervals of 8 steps along the first direction over the substantially entire length of the solar cell 210.

On the surface of the semiconductor substrate 11 corresponding to the first region 61, the back surface connection electrodes 213B are provided in the same number as the number of the first regions 61 of the light-receiving surface bus electrode 212B.

Then, the first region 61 of the light-receiving surface bus bar electrode 212B located outside the end side in the first direction, that is, located on the inner side in the first direction, and the back surface connecting electrode 213B are seen through in 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 connection electrode 1132. The center position of the first area 613 and the center position of the back connection electrode 1133, the center position of the first area 614 and the center position of the back connection electrode 1134, the center position of the first area 615 and the center position of the back connection electrode 1135, The center position of the first region 616 is the same as the center position of the back connection electrode 1136 and the center position of the first region 617 is the same as the center position of the back connection electrode 1137.

On the other hand, when the first region 611 located on the end side in the first direction of the light-receiving surface bus bar electrode 212B is connected to the back electrode 1131, and the semiconductor substrate 11 is seen through from the vertical direction of the in-plane direction of the semiconductor substrate 11, the first 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 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 connection electrode 1138.

The arrangement pitch of two adjacent first regions 61 on the inner side in the first direction is the same arrangement pitch. In addition, the arrangement pitch of two adjacent back surface connection electrodes 213B on the inner side in the first direction is the same arrangement pitch. Therefore, the arrangement pitch of two adjacent first regions 61 on the inner side in the first direction is the same as the arrangement pitch of two adjacent back surface connection electrodes 213B on the inner side in the first direction. The arrangement pitch of the first regions 61 is the distance between the center positions of the first regions 61 in the first direction. The arrangement pitch of the back connection electrodes 213B is the distance between the center positions of the back connection electrodes 213B in the first direction.

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

The first area length A2, the first area length A3, the first area length A4, the first area length A5, the first area length A6, and the first area length A7 are the same. The back connection electrode length C2, the back connection electrode length C3, the back connection electrode length C4, the back connection electrode length C5, the back connection electrode length C6, and the back connection electrode length C7 are the same. Therefore, the length A2 of the first region is longer than the length C2 of the back 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 area length A2+distance B3)=(first area length A3+distance B4)=(first area length A4+distance B5)=(first area length A5+distance B6)=(first area 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) ).

Because the center position of the first region 612 in the first direction matches the center position of the back connection electrode 1132 in the first direction, the distance between the end 101 of the solar cell 210 and the center position of the first region 612 in the first direction is The distance from one end 101 of the solar battery cell 210 to the center position of the back 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 connection electrode length C1+distance D2+ back connection electrode length C2/2) is formed.

Since the center position of the first region 617 in the first direction matches the center position of the back connection electrode 1137 in the first direction, the distance from the other end 102 of the solar 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 battery cell 210 to the center of the back connection electrode 1137 is the same distance. That is, (distance B9+first region length A8+distance B8+first region length A7/2)=(distance D9+back connection electrode length C8+distance D8+back connection electrode length C7/2) is formed.

The length A1 of the first region is longer than the length C1 of the back connection electrode. When the semiconductor substrate 11 is seen through from the vertical direction of the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1131 is arranged inside the first region 611 to overlap the first region 611 in the first direction, that is, in the first direction, the back surface The connection electrode 1131 is at a position included in the first area 611.

The length A8 of the first region is longer than the length C8 of the back connection electrode. When the semiconductor substrate 11 is seen through from the vertical direction of the in-plane direction of the semiconductor substrate 11, the back surface connection electrode 1138 is arranged inside the first region 618 to overlap the first region 618 in the first direction, 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 connection electrode length C1 and the back connection electrode length C8 are the same as the back connection electrode length C2.

In the first direction, the arrangement pitch of two adjacent first regions 61 on the end side in the first direction is shorter than the arrangement pitch of two adjacent first regions 61 on the inner side in the first direction. That is, in the light-receiving surface bus bar electrode 212B, the distance between two adjacent first regions 61 on the end side in the first direction is greater than that between two adjacent first regions 61 on the central part in the first direction The interval between two adjacent first regions 61 on the inner side in the first direction of the interval is shorter. Therefore, the distances B2 and B8 are shorter than the distances B3, B4, B5, B6, and B7.

In the first direction, the arrangement pitch of the two adjacent back surface connection electrodes 213B on the end side in the first direction is shorter than the arrangement pitch of the two adjacent back surface connection electrodes 213B on the inner side in the first direction. In other words, the distance between two adjacent rear connection electrodes 213B on the end side in the first direction in the rear connection electrodes 213B in a row is greater than that between the two adjacent rear connection electrodes 213B in the central portion in the first direction The interval between two adjacent back surface connection electrodes 213B on the inner side in the first direction of the interval is shorter. Therefore, the distances D2 and D8 are shorter than the distances D3, D4, D5, D6, and D7.

In the solar battery cell 210 of the third embodiment, the total length of the first region of the light-receiving surface bus electrode 212B in the first direction is higher than that of the light-receiving surface bus electrode 112B of the solar battery cell 110 of the second embodiment. 1 The total length of the area is greatly increased. That is, as shown in FIG. 30, the total length of the first region in the solar battery cell 210, that is, the total length of the first region A1 to the first region 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 electrode 112B of the solar cell 110 of the second embodiment, that is, the total length of the first region A1 to the length of the first region A8 , Department 46mm.

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

Furthermore, 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 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 electrode 212B and the lead 20 in the first direction is longer than the length of the connection region of the back connection electrode 213B and the lead 20 in the first direction long. That is, as shown in FIG. 31, the total length of the back connection electrode C1 to the back connection electrode length C8 is 48 mm. On the other hand, as shown in FIG. 30, the total length of the first area, that is, the total length of the first area A1 to the length of the first area A8 is 76 mm.

The solar battery cell 210 is formed on the entire back surface of the solar battery cell 210 by using the back-side collector electrode 13A using an electrode material containing aluminum. After the heat treatment of the electrode firing, the solar battery cell 210 has a convex curvature on the light-receiving surface side. Therefore, on the light-receiving surface side of the convexly curved solar battery cell 210, more stress for peeling the lead 20 between the electrode and the lead 20 is applied than the back surface side of the solar battery cell 210.

In the solar battery cell 210, the length of the connection region forming the light-receiving surface bus electrode 212B and the lead 20 in the first direction is longer than the length of the back connection electrode 213B in the first direction. Therefore, in the solar battery cell 210, the length of the connection area where the light-receiving surface bus electrode 212B in the first direction and the lead 20 are formed is longer than that of the light-receiving surface bus electrode in the first direction in the solar battery cell 110 of the second embodiment The length of the connection area between 112B and the lead 20 is long. Therefore, in the solar battery cell 210, since the length of the connection area of the light-receiving surface bus electrode 212B and the lead 20 in the first direction is long, and the bonding strength of the light-receiving surface bus electrode 212B and the lead 20 in the first direction can be improved, The peeling of the lead 20 is suppressed.

On the other hand, the back connection electrode 213B of the silver paste electrode formed by applying and firing the silver paste containing the silver electrode material is formed in a state after firing than the light-receiving surface electrode 212 of the silver paste electrode A composition with a large glass composition. After firing, the silver paste electrode is mostly made of silver and glass. In the silver paste electrode, silver has a function of flowing current. In the silver paste electrode, glass has a function of maintaining the bonding strength between the semiconductor substrate 11 and the electrode.

When comparing the light-receiving surface electrode 212 of the silver paste electrode with the back surface connection electrode 213B of the silver paste electrode, the light-receiving surface electrode 212 has a higher ratio of silver in the electrode material than the back connection electrode 213B in order to reduce the resistance in the electrode. In the light-receiving surface electrode 212, in order to reduce the resistance in the electrode, it is preferable to increase the silver ratio in the electrode material as much as possible. On the other hand, on the back side of the solar battery cell 210, the current collector electrode 13A using an electrode material containing aluminum is responsible for the current collecting function of the semiconductor substrate 11. Therefore, in the back connection electrode 213B, by reducing the ratio of silver in the electrode material and increasing the ratio of the glass component in the electrode material, 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 connection electrode 213B in the fired state is higher than that in the electrode material in the light-receiving surface electrode 212 in the fired state. The ratio of the glass component is higher, and the bonding strength between the semiconductor substrate 11 and the back connection electrode 213B can be maintained at a high level without peeling off the back connection electrode 213B. Thereby, even if the total length of the back connection electrode 213B in the first direction is shorter than the total length of the first region of the light-receiving bus bar electrode 212B in the first direction, the solar cell unit 210 can maintain the semiconductor substrate 11 and The bonding strength between the back connection electrodes 213B is to the extent that the back connection electrodes 213B do not peel off.

As described above, in the solar battery cell 210 of the third embodiment, the first region 61 of the light-receiving surface bus bar electrode 212B and the back surface connecting electrode 213B are arranged at corresponding positions in the plane of the semiconductor substrate 11. Therefore, the solar battery cell 210, like the solar battery cell 10 and the solar battery cell 110 described above, can reduce the damage rate of the solar battery cell 210 due to the bending of the solar battery cell 210 when the solar battery module is manufactured.

Furthermore, in the solar battery cell 210 of the third embodiment, at the other end 102 side of the solar battery cell 210 at the interconnecting end of the solar battery cell 210 on the back side, the end surface of the solar battery cell 210 is extended to the back The distance to connect the electrode 213B. Thereby, as in the solar battery cell 110 of the second embodiment, the stress concentration on the bent portion 20a of the lead 20 can be reduced because of the difference in linear expansion coefficient between the light-receiving glass serving as the light-receiving surface protection portion 31 and the lead 20, etc. Since the repetitive stress applied to the bent portion 20a by the temperature cycle during the day and night can be reduced, a solar cell module with excellent long-term reliability can be realized.

Furthermore, in the solar battery cell 210 of the third embodiment, the length of the connection area of the light receiving surface bus electrode 212B and the lead 20 in the first direction is longer than the length of the connection area of the back connection electrode 213B and the lead 20 in the first direction . Therefore, by ensuring that the length of the connection area of the light-receiving surface bus electrode 212B and the lead 20 in the first direction is long, the bonding strength of the light-receiving surface bus electrode 212B and the lead 20 in the first direction can be increased to suppress the lead 20 peel.

The structure of the above embodiment is shown, and an example of the content of the present invention is shown. It is also possible to combine the technologies of the embodiments and other well-known technologies. It can also be omitted without departing from the scope of the gist of the present invention. Change part of the structure.

12B‧‧‧Receiving surface bus electrode

60‧‧‧Through hole

61‧‧‧ Region 1

62‧‧‧ Region 2

63‧‧‧Connect

X, Y‧‧‧ direction

Claims (12)

A solar cell unit comprising: a semiconductor substrate having a pn junction; a light-receiving surface bus bar electrode extending in the first direction on the light-receiving surface side of the semiconductor substrate; and a plurality of back connection electrodes facing the semiconductor The back side of the substrate opposite to the light-receiving surface is dispersedly arranged along the first direction; wherein the light-receiving surface bus electrode is provided along the first direction and penetrates in the thickness direction of the light-receiving surface bus electrode A plurality of through holes; the back connection electrode is disposed in a position of the semiconductor substrate in the thickness direction relative to the light-receiving surface bus bar electrode except for the plurality of through holes, wherein the light-receiving surface bus bar electrode includes : A plurality of first regions in which the through-holes are not provided in the first direction; and a plurality of second regions in which the through-holes are provided in the first direction; wherein the back surface connection electrode is disposed in the plurality of The first region of the semiconductor substrate is located at a relative position in the thickness direction of the semiconductor substrate, wherein the interval between the first regions adjacent to the end side in the first direction is greater than that of the first region adjacent to the inner side in the first direction The interval between the first regions is short. The solar battery cell according to item 1 of the patent application scope, wherein the light-receiving surface bus electrode is directed to the first direction in both ends of the second direction that is perpendicular to the first direction in the plane of the semiconductor substrate Parallel straight line shape. The solar battery cell according to item 1 or 2 of the patent application range, wherein both ends of the light-receiving surface bus bar electrode in the first direction are constituted by the first region. The solar battery cell according to claim 1 or 2, wherein in the first direction, the first region of the light-receiving surface bus bar electrode is arranged at a position opposite to the back surface in the thickness direction of the semiconductor substrate The connection electrode is long. The solar battery cell according to item 3 of the patent application range, wherein in the first direction, the first region of the light-receiving surface bus bar electrode is arranged at a relative position to the back surface connection electrode in the thickness direction of the semiconductor substrate long. The solar battery cell according to claim 1 or 2, wherein the semiconductor substrate has a rectangular shape, and has a first end edge portion of the solar battery cell in the first direction and the first direction The end of the solar cell opposite to the first end is the second end; the distance between the back connecting electrode adjacent to the second end and the second end is greater than that of the adjacent The distance between the back connection electrode of the first end side and the first end side is long. The solar battery cell according to item 3 of the patent application range, wherein the semiconductor substrate has a rectangular shape and has a first end edge portion of the solar battery cell in the first direction and the first direction and the The end of the solar cell unit opposite to the first end, that is, the second end; The distance between the back connection electrode adjacent to the second end side and the second end side is longer than the distance between the back connection electrode adjacent to the first end side and the first end side. The solar battery cell according to item 4 of the patent application range, wherein the semiconductor substrate has a rectangular shape, and has a first end edge portion which is an end of the solar battery cell in the first direction and the first direction and the above The end of the solar cell opposite to the first end is the second end; the distance between the back connecting electrode adjacent to the second end and the second end is greater than that of the adjacent The distance between the back connection electrode at the one end side and the first end side is long. The solar battery cell according to item 5 of the patent application range, wherein the semiconductor substrate has a rectangular shape and has a first end edge portion which is an end portion of the solar battery cell in the first direction and a The end of the solar cell opposite to the first end is the second end; the distance between the back connecting electrode adjacent to the second end and the second end is greater than that of the adjacent The distance between the back connection electrode at the one end side and the first end side is long. A solar battery module, comprising: a plurality of solar battery cells, as described in any one of patent application items 1 to 9; a lead, two adjacent solar battery cells in the first direction In this, the light-receiving surface bus electrode of one of the solar battery cells is connected to the back connection electrode of the other of the solar battery cells. A solar battery module is characterized by comprising: The two solar battery cells according to any one of claims 6 to 9 in a patent application state where the second end of one solar battery cell is opposed to the first end of the other solar battery cell The lower arrangement is adjacent in the first direction; and the lead wire connects the back connection electrode of the one solar battery cell and the light-receiving bus bar electrode of the other solar battery cell; wherein the lead wire connects the one solar battery The back connection electrode on the second end side of the battery cell and the light receiving surface bus electrode on the first end side of the other solar cell. The solar cell module according to claim 10 or 11, wherein the width of the light-receiving surface bus electrode is equal to the width of the lead; the lead is perpendicular to the first direction in the plane of the semiconductor substrate The positions of both side surfaces of the light-receiving surface bus electrode in the second direction and the positions of both side surfaces of the lead in the second direction are located at the same position, and are overlapped and connected to the light-receiving surface bus electrode.

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