WO2017056934A1

WO2017056934A1 - Busbar electrode, solar battery cell, and solar battery module

Info

Publication number: WO2017056934A1
Application number: PCT/JP2016/076749
Authority: WO
Inventors: 圭祐大平; 友亮松野; 山本　真也; 充宏松下
Original assignee: シャープ株式会社
Priority date: 2015-09-29
Filing date: 2016-09-12
Publication date: 2017-04-06
Also published as: CN108140678A; JPWO2017056934A1

Abstract

Provided is a solar battery module in which a decrease in the strength of connection between a busbar electrode and an interconnector is suppressed even in a case where the relative positional relationship between the busbar electrode and the interconnector deviates from a design value. Provided are: a first section (21) extending along a first direction; a second section (22) and a third section (23) that extend along the first direction and that are provided so as to sandwich the first section (21) therebetween and so as to be apart from the first section (21) in a second direction intersecting the first direction; and a fourth section (24) that extends along the second direction and that connects the first section (21), the second section (22), and the third section (23) to one another.

Description

Bus bar electrode, solar battery cell, and solar battery module

This application claims the benefit of priority to Japanese Patent Application No. 2015-190971 filed on Sep. 29, 2015, and the contents of which are incorporated herein by reference. .

An embodiment of the present invention relates to a bus bar electrode, a solar battery cell, and a solar battery module.

Japanese Patent Application Laid-Open No. 2007-150356 discloses a solar cell in which a surface electrode including a bus bar portion (bus bar electrode) provided with a slit portion and a finger portion (finger electrode) is formed. The slit part is formed in a direction parallel to or perpendicular to the finger part. The bus bar portion is connected to the surface copper foil (interconnector). The surface electrode is formed using a paste made of silver powder, glass frit, a binder, and a solvent.

JP 2007-150356 A

The bus bar electrode is connected to the interconnector. Therefore, from the viewpoint of increasing the bonding strength between the bus bar electrode and the interconnector, and from the viewpoint of reducing the alignment accuracy when forming the interconnector on the bus bar electrode, the bus bar electrode is formed in a wider area. preferable.

However, in the solar cell in which the slit portion is formed in a direction parallel to or perpendicular to the finger electrode, the relative positional relationship between the bus bar electrode and the interconnector is the above described design value (hereinafter also referred to as a reference state). When misaligned in the parallel direction, the bonding area between the bus bar electrode and the interconnector decreases, and there is a problem that the connection strength between the two decreases.

The embodiment disclosed herein has been made to solve the above-described problems. The main purpose of the embodiment disclosed herein is to suppress a decrease in the connection strength between the bus bar electrode and the interconnector even when the relative positional relationship between the bus bar electrode and the interconnector is displaced from the design value. Another object is to provide a solar cell module.

The bus bar electrode according to the embodiment disclosed herein is provided in a solar battery cell, and is connected to the interconnector in a solar battery string in which a plurality of the solar battery cells are electrically connected via an interconnector. It is a bus bar electrode. The bus bar electrode includes a first portion extending along a first direction and a second portion extending along the first direction and intersecting the first direction. A second portion and a third portion arranged to be spaced apart from the first portion, and extending along the second direction, and the first portion, the second portion, and the And a fourth portion connecting the third portions to each other.

According to the embodiment disclosed herein, even when the relative positional relationship between the bus bar electrode and the interconnector is displaced from the design value, a decrease in the adhesive strength between the bus bar electrode and the interconnector is suppressed. A solar cell module can be provided.

It is a top view of the photovoltaic cell which concerns on this Embodiment. It is the elements on larger scale of the area | region II in FIG. FIG. 3 is a cross-sectional view seen from an arrow III-III in FIG. FIG. 4 is a cross-sectional view seen from arrows IV-IV in FIG. It is a rear view of the photovoltaic cell which concerns on this Embodiment. (A)-(c) is sectional drawing which shows the manufacturing method of the photovoltaic cell concerning this Embodiment. It is a top view which shows the reference | standard state of the connection part of a bus-bar electrode and an interconnector in the solar cell string which concerns on this Embodiment. It is sectional drawing which shows the reference | standard state of the connection part of a bus-bar electrode and an interconnector in the solar cell string which concerns on this Embodiment. It is a top view which shows the state which the position of the connection part of a bus-bar electrode and an interconnector shifted | deviated from the reference state in the solar cell string which concerns on this Embodiment. It is sectional drawing which shows the state which the connection part of a bus-bar electrode and an interconnector shifted from the reference | standard state in the solar cell string which concerns on this Embodiment. It is a top view which shows the other modification of the connection part of a bus-bar electrode and an interconnector in the solar cell string which concerns on this Embodiment. It is sectional drawing which shows the other modification of the connection part of a bus-bar electrode and an interconnector in the solar cell string which concerns on this Embodiment. It is sectional drawing which shows the solar cell module which concerns on this Embodiment. It is a rear view which shows the modification of the photovoltaic cell concerning this Embodiment.

Embodiments of the present invention will be described below with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.
<Solar cell>
First, solar cell 1 and bus bar electrode 20 according to the present embodiment will be described with reference to FIGS. The solar cell 1 is formed on the first main surface 10A and the semiconductor substrate 10 having the first main surface 10A and the second main surface 10B located on the opposite side of the first main surface 10A. Bus bar electrode 20, finger electrode 30, and antireflection film 50, and back bus bar electrode 60, back finger electrode 31, and antireflection film 51 formed on second main surface 10B.

The semiconductor substrate 10 is, for example, an n-type or p-type single crystal or polycrystalline silicon substrate. As shown in FIG. 3, the semiconductor substrate 10 includes a p-type region 11 and an n-type region 12. The p-type region 11 has a first main surface 10A, and the n-type region 12 has a second main surface. It has a surface 10B. The first main surface 10A and the second main surface 10B are formed with unevenness (texture structure), and constitute a light receiving surface.

1 and FIG. 2, the bus bar electrode 20 extends along the first direction A. A plurality of bus bar electrodes 20 are formed, for example, spaced apart from each other in a second direction B intersecting (for example, orthogonal to) the first direction A. The bus bar electrode 20 extends along the first direction A, extends along the first direction A, and is spaced apart from the first portion 21 in the second direction B. It has the 2nd part 22 and the 3rd part 23 which are arrange | positioned so that the 1st part 21 may be pinched | interposed. Further, the bus bar electrode 20 has a fourth portion 24 that extends in the second direction B and connects the first portion 21, the second portion 22, and the third portion 23 to each other. For example, a plurality of fourth portions 24 are formed at intervals in the first direction A. For example, the first portion 21 is disposed so as to overlap the center line of the bus bar electrode 20 in the second direction B.

As shown in FIG. 3, the bus bar electrode 20 (the first portion 21, the second portion 22, the third portion 23, the fourth portion 24, and the convex portion 25) has a first direction A and a second direction B. It has a surface 20A in a third direction (thickness direction of the semiconductor substrate 10) orthogonal to each other.

The width W1 of the first portion 21 in the second direction B is wider than the width W2 of the second portion 22 in the second direction B and the width W3 of the third portion 23 in the second direction B. The width W2 of the second portion 22 in the second direction B and the width W3 of the third portion 23 in the second direction B are, for example, equal. The width W1 of the first portion 21 is, for example, not less than 0.2 mm and not more than 0.5 mm. The widths W2, W3 of the second portion 22 and the third portion 23 are, for example, not less than 0.1 mm and not more than 0.5 mm.

As shown in FIGS. 2 to 4, the bus bar electrode 20 includes an antireflection film, which will be described later, between the first portion 21 and the second portion 22 and between the first portion 21 and the third portion 23. A hollow portion 40 where 50 is exposed is formed. In other words, the bus bar electrode 20 includes a plurality of hollow portions 40 that are continuous with the fourth portion 24 in the first direction A, and a plurality of the continuous portions 40 that are continuous with the first portion 21 in the second direction B. A hollow portion 40 is formed. The number of the hollow portions 40 arranged side by side in the second direction B is an even number, and can be, for example, 2, 4, 6, or 8. When three hollow portions 40 are arranged side by side in the second direction B, for example, they extend along the first direction A and the second portion 22 is between the first portion 21 and the second portion 22. A fifth portion (not shown) is formed so as to be spaced from the second portion 22 so as to be sandwiched. A hollow portion 40 is formed between the fifth portion and the second portion 22. The plurality of hollow portions 40 may have different shapes or dimensions, or may have the same shape and dimensions.

The planar shape of the hollow portion 40 formed in the bus bar electrode 20 may be any shape. For example, two parallel lines extending along the first direction A are in the second direction B. It is a shape joined by a curved line extending in an arc shape. A width W4 of the hollow portion 40 in the second direction B is, for example, the same as the width W1 of the first portion 21 or wider than the width W1. The width W4 of the hollow portion 40 is, for example, not less than 0.1 mm and not more than 1.0 mm. The total width (W4 × 2 in FIG. 2) of the plurality of hollow portions 40 arranged side by side in the second direction B is a width W7 in the second direction B of the interconnector 70 described later (see FIG. 7). ) Is preferably 60% or more and 80% or less. The width W6 of the bus bar electrode 20 in the second direction B is, for example, not less than 0.8 mm and not more than 2.5 mm, and preferably not less than 1.0 mm and not more than 2.0 mm. The ratio of the width W1 of the first portion 21 to the width W6 of the bus bar electrode 20 is 20% or more.

The area of the surface 20A (see FIG. 2) of the bus bar electrode 20 is 60% or more of the area of the surface of the bus bar electrode which is not provided with the hollow portion 40 and is configured as a line having the width W6. Is preferred. In other words, the total area of the plurality of hollow portions 40 is 40% or less of the area of the surface of the bus bar electrode which is not provided with the hollow portions 40 and is configured as a line having the width W6. Is preferred.

As shown in FIG. 3, the bus bar electrode 20 protrudes partially from the second portion 22 in the second direction B and partially protrudes from the third portion 23 in the second direction B. And a convex portion 25b. The

convex portions

25 a and 25 b are continuous with the fourth portion 24 in the second direction B. Further, the

convex portions

25 a and 25 b are continuous with the finger electrode 30 in the second direction B. In addition, any one of the

convex portions

25a and 25b may be formed. The thickness of the bus bar electrode 20 is equal to the thickness of the finger electrode 30, for example. The material constituting the bus bar electrode 20 includes, for example, at least one selected from the group consisting of silver (Ag), copper (Cu), and aluminum (Al).

1 and 2, the finger electrode 30 extends in the second direction B. A plurality of finger electrodes 30 are formed, for example, in the first direction A at intervals. The finger electrode 30 is formed in the second direction B so as to be continuous with the

convex portions

25a and 25b. The finger electrode 30 is formed so as to be continuous in the second direction B with the central portion of each of the

convex portions

25 a and 25 b in the first direction A. The width of the finger electrode 30 in the first direction A is narrower than the minimum width of the fourth portion 24 in the first direction A. The material constituting the finger electrode 30 includes, for example, at least one selected from the group consisting of Ag, Cu, and Al.

As shown in FIGS. 1 and 2, the antireflection film 50 covers a region where the bus bar electrode 20 and the finger electrode 30 are not formed on the first main surface 10A. The antireflection film 50 is, for example, a silicon oxide film, a silicon nitride film, a silicon film containing both oxygen and nitrogen, or a multilayer film thereof.

Referring to FIGS. 3 and 5, back-side bus bar electrode 60 has the same configuration as bus bar electrode 20. The back bus bar electrode 60 extends along the first direction A. A plurality of back surface bus bar electrodes 60 are formed, for example, spaced apart from each other in a second direction B intersecting (for example, orthogonal to) the first direction A. The back surface bus bar electrode 60 extends along the first direction A, extends along the first direction A, and is spaced apart from the first portion 61 in the second direction B. The second portion 62 and the third portion 63 are arranged so as to sandwich the first portion 61 therebetween. Furthermore, the back surface bus bar electrode 60 has a fourth portion 64 that extends along the second direction B and connects the first portion 61, the second portion 62, and the third portion 63 to each other. For example, a plurality of fourth portions 64 are formed at intervals in the first direction A. The backside bus bar electrode 60 has a hollow portion 41 where the antireflection film 51 is exposed between the first portion 61 and the second portion 62 and between the first portion 61 and the third portion 63. Is formed. The back surface bus bar electrode 60 includes a convex portion 65a partially protruding from the second portion 62 in the second direction B and a convex portion 65b partially protruding from the third portion 63 in the second direction B.

The back surface bus bar electrode 60 is formed, for example, in a region overlapping the bus bar electrode 20 in a direction perpendicular to the second main surface 10B. The first portion 61, the second portion 62, the third portion 63, the fourth portion 64, the

convex portions

65a and 65b, and the hollow portion 41 are each a first portion in a direction perpendicular to the second main surface 10B, for example. 21, the second portion 22, the third portion 23, the fourth portion 24, the

convex portions

25 a and 25 b, and the hollow portion 40.

The back finger electrode 31 has the same configuration as the finger electrode 30. The antireflection film 51 has the same configuration as the antireflection film 50. As shown in FIG. 8, the solar cell string 2 is configured by connecting the bus bar electrode 20 and the back bus bar electrode 60 to the interconnector 70.
<Solar cell manufacturing method>
Next, with reference to FIG. 6, the manufacturing method of the photovoltaic cell 1 which concerns on this Embodiment is demonstrated. Referring to FIG. 6A, first, p + region 11 is formed on first main surface 10A of semiconductor substrate 10 having a texture structure, and n + region 12 is formed on second main surface 10B. Referring to FIG. 6B, next, an antireflection film 50 is formed so as to cover the first main surface 10A. Further, an antireflection film 50 is formed so as to cover the first main surface 10A. A method of forming the antireflection film 50 is, for example, a plasma CVD method.

Referring to FIG. 6C, next, bus bar electrode 20 and finger electrode 30 are formed on first main surface 10A. Further, back bus bar electrode 60 and back finger electrode 31 are formed on second main surface 10B. The

bus bar electrodes

20 and 60 and the

finger electrodes

30 and 31 are formed, for example, by screen printing silver paste and baking. The

bus bar electrodes

20 and 60 may be formed after the

finger electrodes

30 and 31 are formed. For example, the finger electrode 30 extending along the second direction B and the conductive member to be a part of the fourth portion 24 are formed over the entire solar cell 1, and then along the first direction A. A conductive member to be the extended bus bar electrode 20 can also be formed. The bus bar electrode 20 and the finger electrode 30 may be formed after the back surface bus bar electrode 60 and the back surface finger electrode 31 are formed. Further, the

antireflection films

50 and 51 may be formed after the

bus bar electrodes

20 and 60 and the

finger electrodes

30 and 31 are formed.
<Solar cell string>
Next, with reference to FIG. 7 and FIG. 8, the solar cell string 2 which concerns on this Embodiment is demonstrated. In the solar cell string 2, a plurality of solar cells 1 are electrically connected in series by an interconnector 70. The interconnector 70 electrically connects one bus bar electrode 20 and the other back surface bus bar electrode 60 in two adjacent solar cells 1. The interconnector 70 includes a first connection portion 71 connected to the bus bar electrode 20, a second connection portion 72 connected to the back surface bus bar electrode 60, and a space between the first connection portion 71 and the second connection portion 72. And a third connection portion 73 for connecting the two. The material constituting the interconnector 70 may be any material having conductivity, but includes at least one selected from the group consisting of Ag, Cu, Al, Pb, and Sn, for example.

As shown in FIG. 7, the width W7 in the second direction B of the first connection portion 71 of the interconnector 70 is equal to, for example, the width W6 of the bus bar electrode 20. At this time, it is preferable that the bus bar electrode 20 has the first portion 21, the second portion 22, the third portion 23, and the fourth portion 24 as a whole connected to the first connection portion 71 of the interconnector 70. A center line (line segment C in FIG. 7) passing through the center in the second direction B of the bus bar electrode 20 (for example, the first portion 21) and extending along the first direction A, and the second of the interconnector 70 And a center line (line segment D in FIG. 7) passing through the center in the direction B and extending along the first direction A are arranged so as to overlap each other. Hereinafter, with respect to the relative positional relationship between the bus bar electrode 20 and the interconnector 70, a state in which the center lines are arranged so as to overlap each other is referred to as a reference state. The reference state is a state in which the position is not shifted from the design value in the solar cell string 2, for example. The convex portions 25 and the finger electrodes 30 of the bus bar electrode 20 are not connected to the interconnector 70 and are exposed in the solar cell string 2. At this time, the hollow portion 40 of the bus bar electrode 20 is completely covered by the interconnector 70. In other words, the light receiving surface in the solar cell string 2 is a region surrounded by the bus bar electrode 20 and the finger electrode 30.

On the other hand, referring to FIG. 9 and FIG. 10, the bus bar electrode 20 includes a first connection portion of the interconnector 70 in which at least part of the first portion 21, the second portion 22, the third portion 23, and the fourth portion 24 71 may be connected. For example, as long as at least a part of the first part 21 is connected to the first connection part 71, at least one of the second part 22 and the third part 23 and a part of the fourth part 24 are connected to the first connection part. 71 may be connected. The hollow portion 40 of the bus bar electrode 20 is partially covered by the interconnector 70. A portion adjacent to the convex portion 25 in the convex portion 25 and the finger electrode 30 is connected to the interconnector 70. At this time, since the light can reach the hollow portion 40, the region located in the hollow portion 40 can also act as a light receiving surface.

In the bus bar electrode 20, the connection area of the region connected to the interconnector 70 is preferably 80% or more when the state (reference state) shown in FIGS. 7 and 8 is 100%. In this case, the connection strength between the bus bar electrode 20 and the interconnector 70 can be further increased. In addition, the connection area connected to the bus bar electrode 20 in the interconnector 70 is preferably 80% or more when the reference state is 100%.

In addition, the width W7 of the interconnector 70 may be 2/3 times or more and 1 time or less of the width W6 of the bus bar electrode 20. In other words, the width W6 of the bus bar electrode 20 may be 1 to 1.5 times the width W7 of the interconnector 70. The width W7 of the interconnector 70 is, for example, not less than 0.5 mm and not more than 2.0 mm, preferably not less than 1.3 mm and not more than 1.8 mm. The ratio of the width W1 of the first portion 21 to the width W7 of the interconnector 70 is not less than 30% and not more than 60%.

11 and 12, the width W6 of the bus bar electrode 20 is 1.5 times the width W7 of the interconnector 70, and the center lines of the bus bar electrode 20 and the interconnector 70 are arranged so as to overlap each other. The solar cell string 2 in a state (reference state) is shown. One end and the other end of the first connector 71 of the interconnector 70 in the second direction B are formed at positions overlapping the hollow portion 40. Also in this case, the connection area between the bus bar electrode 20 and the interconnector 70 is preferably 80% or more when the reference state shown in FIGS. 11 and 12 is 100%. For example, when the interconnector 70 is displaced in the second direction B with respect to the reference state and is connected to the entire first portion 21 and the second portion 22 of the bus bar electrode 20, the connection area exceeds 100%. It becomes.
<Solar cell module>
Next, the solar cell module 3 according to the present embodiment will be described with reference to FIG. The solar cell module 3 is disposed on the plurality of solar cell strings 2, the sealing material 80 and the transparent substrate 81 disposed on the first main surface 10A side of the solar cell string 2, and the second main surface 10B side. A sealing material 80 and a back film 82. In the solar cell module 3, the interconnector 70 is electrically connected to the bus bar electrode 20 of one adjacent solar cell 1 and is also electrically connected to the rear bus bar electrode 60 of the other solar cell 1. ing. As the sealing material 80, for example, a resin transparent to sunlight can be used without particular limitation, and for example, ethylene vinyl acetate can be used. As the transparent substrate 81, for example, a substrate transparent to sunlight can be used without particular limitation, and for example, a glass substrate or the like can be used. As the back film 82, for example, a conventionally used sheet such as a weather-resistant film can be used without any particular limitation, and it is preferable to use a film having a metal film sandwiched between insulating films.

Note that, in the solar cell 1 according to the present embodiment, only one of the first main surface 10A and the second main surface 10B may be formed as a light receiving surface. The bus bar electrode of the solar battery cell 1 may be formed only on one of the first main surface 10A and the second main surface 10B. Referring to FIG. 14, for example, when only first main surface 10A is formed as a light receiving surface, bus bar electrode 20 (see FIG. 2) is formed on second main surface 10B (see FIG. 1). The back surface electrode 90 provided with the same structure may be formed. The back electrode 90 extends along the first direction A, extends along the first direction A, and is spaced apart from the first portion 91 in the second direction B. It has the 2nd part 92 and the 3rd part 93 which are arrange | positioned so that the 1st part 91 may be pinched | interposed. Further, the back electrode 90 has a fourth portion 94 that extends along the second direction B and connects the first portion 91, the second portion 92, and the third portion 93 to each other. For example, a plurality of fourth portions 94 are formed at intervals in the first direction A.
<Effect>
Next, functions and effects of the bus bar electrode 20, the solar battery cell 1, the solar battery string 2, and the solar battery module 3 according to the present embodiment will be described.

The bus bar electrode 20 is disposed at a distance from the first portion 21 located in the center in the second direction B and the first portion 21 so as to sandwich the first portion 21 in the second direction B. A hollow portion 40 is formed between the portion 22 and the third portion. The bus bar electrode 20 has a width W6 in the second direction B equal to or greater than that of the conventional bus bar electrode while suppressing the content of Ag or the like lower than that of the bus bar electrode having the conventional slit portion. be able to. Furthermore, according to the bus bar electrode 20, even if the interconnector 70 is displaced from the reference state, at least one of the first portion 21 and at least one of the second portion 22 and the third portion 23 is used. Can be connected simultaneously with the interconnector 70. Therefore, according to the bus bar electrode 20 according to the present embodiment, the connection strength between the bus bar electrode 20 and the interconnector 70 even when the relative positional relationship between the bus bar electrode and the interconnector is displaced from the reference state. Can be provided. If it says from a different viewpoint, according to the bus-bar electrode 20 which concerns on this Embodiment, the positional offset tolerance of the interconnector 70 with respect to the bus-bar electrode 20 can be made larger than the said conventional bus-bar electrode. Therefore, the solar cell string 2 and the solar cell module 3 in which the plurality of solar cells 1 including the bus bar electrode 20 are electrically connected via the interconnector 70 are compared with the conventional solar cell string and the solar cell module. The bus bar electrode 20 and the interconnector 70 can be easily connected. Furthermore, the solar cell 1, the solar cell string 2, and the solar cell module 3 including the bus bar electrode 20 can reduce the Ag content as compared to the conventional solar cell, solar cell string, and solar cell module. Therefore, the manufacturing cost can be kept low. Further, since the hollow portion 40 can also be configured as a light receiving surface according to the relative positional relationship between the bus bar electrode 20 and the interconnector 70, the light receiving area can be increased while the width W6 of the bus bar electrode 20 is increased. Is also possible.

In the bus bar electrode 20, the connection area of the region connected to the interconnector 70 on the surface 20A is 80% or more of the connection area when the relative positional relationship between the bus bar electrode 20 and the interconnector 70 is in the reference state. It is preferably 100% or less. In this case, it is possible to provide the solar battery cell 1 in which a decrease in connection strength between the bus bar electrode 20 and the interconnector 70 is suppressed.

In the bus bar electrode 20, the ratio (W6 / W7) of the width W6 in the second direction B of the bus bar electrode 20 to the width W7 in the second direction B of the interconnector 70 is 1 or more and 1.5 or less. preferable. If it does in this way, when connecting the photovoltaic cells 1 mutually by the interconnector 70, position alignment of the interconnector 70 with respect to the bus-bar electrode 20 can be made easy. The width W6 of the bus bar electrode 20 includes the width W4 of the hollow portion 40. For this reason, the bus bar electrode 20 has a reduced Ag content compared to the bus bar electrode having the width W6 in which the hollow portion 40 is not formed, and thus the manufacturing cost is kept low.

In the bus bar electrode 20, the total value of the distance between the first portion 21 and the second portion 22 and the distance between the first portion 21 and the third portion 23 with respect to the width W 7 in the second direction B of the interconnector 70 is 60. % Or more is preferable. In other words, the ratio of the total value of the width W4 of the plurality of hollow portions 40 formed side by side along the second direction B with respect to the width W7 of the interconnector 70 is preferably 60% or more and 80% or less. In this way, the width W6 in the second direction B of the bus bar electrode 20 can be increased while suppressing the Ag content of the bus bar electrode 20 as compared with the bus bar electrode 20 having the ratio of less than 60%. it can. Moreover, since the inner peripheral area | region of the hollow part 40 can comprise a light-receiving surface, the reduction | decrease of the light-receiving area of the photovoltaic cell 1 can be suppressed, making the said width | variety W6 of the bus-bar electrode 20 wide.

According to the solar cell 1, since the bus bar electrode 20 is provided, the bus bar electrode 20 and the interconnector 70 can be easily connected with high strength. Therefore, the solar cell string 2 and the solar cell module 3 in which the plurality of solar cells 1 are connected via the interconnector 70 are lower in manufacturing cost and the bus bar electrode than the conventional solar cell string and solar cell module. The connection strength between the connector 20 and the interconnector 70 is high.

Since the plurality of finger electrodes 30 are connected to one bus bar electrode 20, the solar cell 1 can collect carriers from a wide area of the light receiving surface and collect current. Furthermore, since the finger electrode 30 and the 4th part 24 are each connected in the 2nd direction B, the electrically-conductive member which should become the finger electrode 30 extended along the 2nd direction B is used for the photovoltaic cell 1, for example. After forming over the whole, by forming a conductive member to be the bus bar electrode 20 extending along the first direction A (particularly, the conductive member to be the fourth portion 24 is a part of the conductive member). The solar battery cell 1 can be easily manufactured.

Since the solar battery string 2 includes the solar battery cell 1 including the bus bar electrode 20, the bus bar electrode 20 and the interconnector 70 are connected with high connection strength. Therefore, the solar cell string 2 has a lower manufacturing cost and a higher connection strength between the bus bar electrode 20 and the interconnector 70 than the conventional solar cell string. Moreover, since the solar cell module 3 includes the solar cell string 2, the manufacturing cost is low and the connection strength between the bus bar electrode 20 and the interconnector 70 is high as compared with the conventional solar cell module.

<Sample>
In this embodiment, the solar cell string 2 (sample 1) in which the ratio of the width W6 in the second direction B of the bus bar electrode 20 to the width W7 in the second direction B of the interconnector 70 is 1, and the ratio is 1 .15 solar cell string 2 (sample 2) and solar cell string 2 (sample 3) having a ratio of 1.5.

Specifically, as the sample 1, the width W1 of the first portion 21 is 0.3 mm, the widths W2 and W3 of the second portion 22 and the third portion 23 are 0.2 mm, and the width W4 of the hollow portion 40. Is connected to the bus bar electrode 20 having the width W6 of 1.3 mm and the interconnector 70 having the width W7 of 1.3 mm in the second direction B. A solar cell string 2 was prepared. As the sample 2, the width W1 of the first portion 21 is 0.3 mm, the widths W2 and W3 of the second portion 22 and the third portion 23 are 0.2 mm, the width W4 of the hollow portion 40 is 0.4 mm, In the second direction B, two hollow portions 40 are arranged side by side, and the solar cell string 2 in which the bus bar electrode 20 having the width W6 of 1.5 mm and the interconnector 70 having the width W7 of 1.3 mm are connected. Was made. As the sample 3, the width W1 of the first portion 21 is 0.3 mm, the widths W2 and W3 of the second portion 22 and the third portion 23 are 0.1 mm, the width W4 of the hollow portion 40 is 0.25 mm, Two solar cell strings 2 in which two hollow portions 40 are arranged in the second direction B and the bus bar electrode 20 having a width W6 of 1.5 mm and the interconnector 70 having a width W7 of 1.0 mm are connected. Was made. Table 1 shows parameters of the solar cell strings 2 of Sample 1 and Sample 2.

In the solar cell strings 2 of Samples 1 to 3, the relative positional relationship between the bus bar electrode 20 and the interconnector 70 was in the reference state. The total value of the distance between the first portion 21 and the second portion 22 and the distance between the first portion 21 and the third portion 23 with respect to the width W7 in the second direction B of the interconnector 70 is 46 for the sample 1. %, Sample 2 was 61%, and sample 3 was 60%.

<Evaluation>
For the produced solar cell strings 2 of Samples 1 to 3, a peel test was performed on the connection portion between the bus bar electrode 20 and the interconnector 70, and the connection strength between the bus bar electrode 20 and the interconnector 70 was evaluated. In the peel test, the bus bar electrode 20 and the interconnector 70 are welded at a temperature of 150 to 250 degrees, and then the bus bar electrode 20 and the interconnector 70 are reversed (using a force gauge manufactured by Nidec Sympo Co., Ltd.) It was performed by pulling in directions different from each other by 180 degrees. In the peel test, the force (peel strength) when the connecting portion between the bus bar electrode 20 and the interconnector 70 was broken was measured.

<Result>
Table 2 shows the results of peel strength measurement performed on the solar cell strings 2 of Samples 1 to 3 produced.

According to this example, it was confirmed that the solar cell strings 2 of Sample 1 to Sample 3 are connected to the bus bar electrode 20 and the interconnector 70 with sufficient strength.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 solar cell, 2 solar cell string, 3 solar cell module, 10 semiconductor substrate, 10A first main surface, 10B second main surface, 11 n-type region, 12 p-type region, 20 busbar electrode, 20A surface, 21, 61 1st part, 22, 62 2nd part, 23, 63 3rd part, 24, 64 4th part, 25a, 25b, 65a, 65b convex part, 30, 31 finger electrode, 40, 41

hollow part

50, 51 Antireflection film, 60 Back busbar electrode (busbar electrode), 70 Interconnector, 71 First connection, 72 Second connection, 73 Third connection, 80 Sealant, 81 Transparent substrate, 82 Back the film.

Claims

A bus bar electrode connected to the interconnector in a solar battery string provided in a solar battery cell, wherein a plurality of the solar battery cells are electrically connected via an interconnector,
A first portion extending along a first direction; and a second portion extending along the first direction and intersecting the first direction so as to sandwich the first portion. A second portion and a third portion disposed at a distance from the first portion; and extending along the second direction; and the first portion, the second portion, and the third portion A bus bar electrode comprising a fourth portion connected to each other.
A semiconductor substrate having a first major surface;
A solar battery cell comprising the bus bar electrode according to claim 1 on the first main surface.
The semiconductor substrate further includes a second main surface located on the opposite side of the first main surface,
The photovoltaic cell according to claim 2, further comprising the bus bar electrode on the second main surface.
A finger electrode extending along the second direction and connected to the second portion and the third portion;
4. The solar cell according to claim 2, wherein the finger electrode and the fourth portion are continuous in the second direction. 5.
The bus bar electrode includes a convex portion that partially protrudes in the second direction from at least one of the second portion and the third portion in the second direction,
The solar cell according to claim 4, wherein the convex portion is continuous with the finger electrode.
A plurality of the solar cell strings are provided,
The solar cell string is
A plurality of solar cells according to any one of claims 2 to 5,
The interconnector for electrically connecting a plurality of the solar cells, and
The interconnector is a solar cell module that is electrically connected to the bus bar electrode of at least one of the adjacent solar cells.
The connection area of the region connected to the interconnector is 80% or more and 100% or less of the connection area when the relative positional relationship between the bus bar electrode and the interconnector is in a reference state. 6. The solar cell module according to 6.
The solar cell module according to claim 6 or 7, wherein a ratio of a width in the second direction of the bus bar electrode to a width in the second direction of the interconnector is 1 or more and 1.5 or less.
The distance between the first part and the second part in the second direction and the distance between the first part and the third part in the second direction with respect to the width of the interconnector in the second direction The solar cell module according to claim 8, wherein the total is 60% or more and 80% or less.