WO2017128669A1

WO2017128669A1 - Crystalline silicon solar cell

Info

Publication number: WO2017128669A1
Application number: PCT/CN2016/092195
Authority: WO
Inventors: 何凤琴; 钱俊
Original assignee: 王能青
Priority date: 2016-01-28
Filing date: 2016-07-29
Publication date: 2017-08-03
Also published as: CN105679849A; CN105679849B

Abstract

A crystalline silicon solar cell, comprising a cell body (1), as well as a front electrode (2) positioned at the front face of the cell body (1) and a rear electrode (3) positioned at the rear face of the cell body (1), the front electrode (2) comprising multiple secondary grid lines (10) extending in a first direction (Y) and arranged in rows at regular intervals, and said front electrode (2) also comprising a number M of fine grid lines (20) extending in a second direction (X) and arranged in rows at regular intervals, the width (D1) of said fine grid lines (20) being 0.10-0.25mm; a number N of welding contacts (30) are provided at intervals on each fine grid line (20), the welding contacts (30) being layered over the fine grid line (20), the shapes of the welding contacts (30) being two or more of square, circular and elliptical, the length (L1) of a side of a square, diameter (R) of a circle or length (L2) of the short axis of an ellipse being greater than the width (D1) of a fine grid line (20); the rear electrode (3) comprises a number N×M of electrode units (31), the electrode units (31) and welding contacts (30) corresponding one-to-one, and the length of each electrode unit (31) along the first direction (Y) and the second direction (X) being no shorter than the length of a welding contact (30) along the corresponding direction.

Description

Crystal silicon solar cell

Technical field

The present invention relates to the field of solar cell technologies, and in particular, to a crystalline silicon solar cell.

Background technique

A crystalline silicon solar cell is an electronic component that converts solar energy into electrical energy. The preparation of crystalline silicon solar cells is generally carried out by processes such as texturing, diffusion, coating, screen printing, and sintering. The velvet is divided into single crystal and polycrystalline velvet. The single crystal battery is formed by the method of alkali velvet to form a pyramid suede on the surface of the silicon wafer, and the polycrystalline battery is formed by using an acid etching method to form a pitted surface on the surface of the silicon wafer. The suede surface of the silicon surface can increase the absorption of sunlight on the surface of the battery to achieve the light trapping effect; the diffusion process forms a PN junction into the interior of the silicon wafer by means of thermal diffusion, so that when light is irradiated, a voltage can be formed inside the silicon wafer. It is the basis of solar cell power generation; the coating process is to reduce the composite of minority carriers on the surface of the battery, and can improve the conversion efficiency of the crystalline silicon solar cell; the screen printing process is to make the electrode of the solar cell, so that when the light is irradiated It is possible to derive the current. Screen printing is one of the most widely used processes in the preparation of crystalline silicon cells. The process sequence is to first print and dry the back electrode, then print and dry the aluminum back field, and finally print and dry the front electrode. When sintering is performed, the silver paste used for preparing the electrode is brought into contact with the battery.

In the front electrode of the crystalline silicon solar cell, the electrode structure generally includes a main gate line and a sub-gate line which are criss-crossed, and the main gate line is electrically connected to the sub-gate line. When there is light, the battery generates a current, and the current flows through the internal emitter to the surface electrode sub-gate line, collects through the sub-gate line and then flows to the battery main grid for export. The current will be lost during the collection of the secondary gate line, which we call the power loss of the resistor. The main grid line and the sub-gate line of the battery are on the light-receiving surface of the battery, which inevitably blocks a part of the light from being irradiated on the surface of the battery, thereby reducing the effective light-receiving area of the battery, which is called optical loss. Regardless of whether it is a P-type or an N-type battery, as long as the electrode structure exists on the front side of the battery, it is necessary to consider the continuous optimization of the electrode structure to achieve the purpose of reducing the shading area and ensuring smooth current export.

In the conventional front electrode structure, the number of main gate lines is usually three, and the width thereof is about 1.5 mm; the number of the sub-gate lines is usually 80 to 100, and the width thereof is about 40 μm. The width of the main gate line is wide, so that the front electrode and the battery ribbon can be soldered well, but the light shielding area is also large. In recent years, for In order to reduce the light-shielding area of the front electrode, the industry has proposed a front electrode structure without a main gate, which mainly removes three main gate lines in the front electrode structure, and only retains the sub-gate line. After the battery is completed, the use is extremely fine. The cylindrical ribbon is directly soldered to the secondary grid and the current is directly extracted by the ribbon. In the welding process of the extremely thin soldering strip and the sub-gate line, the power of the photovoltaic module is lowered due to the abnormality of the soldering or the inability to solder due to the small width of the sub-gate line and the sub-gate line being too low.

Summary of the invention

In view of the deficiencies of the prior art, the present invention provides a crystalline silicon solar cell. By improving the structure of the front electrode, the front electrode structure can achieve the purpose of reducing the shading area and ensuring smooth current export; further, corresponding The back electrode structure in the solar cell is improved, and the amount of silver paste in the back electrode structure is saved.

In order to achieve the above object, the present invention adopts the following technical solutions:

A crystalline silicon solar cell includes a battery body and a front electrode on a front surface of the battery body and a back electrode on a back surface of the battery body, wherein the front electrode further includes M fine grid lines arranged at intervals in the second direction, The fine gate line is electrically connected to the sub-gate line, and the width of the fine gate line is 0.10-0.25 mm; wherein M=10-20; wherein each fine gate line is further provided with N spaced apart Welding contacts are disposed on the fine grid line and electrically connected to the fine grid lines, and the welding contacts are shaped as two of a square, a circle and an ellipse More specifically, the length of the side of the square, the diameter of the circle, or the length of the short side of the ellipse are respectively 0.2 to 1 mm, and the length of the side of the square, the diameter of the circle, or the length of the short side of the ellipse are respectively More than the width of the fine grid line; wherein N=5-15; the back electrode comprises N×M electrode units, the electrode unit corresponds to the soldering contact one by one, and the electrode unit is first The length in the direction and the second direction are not less than the welding, respectively The length of the contact in the corresponding direction.

Further, the soldering contact is formed on the fine grid line by a secondary printing process.

Further, the plurality of sub-gate lines are equally spaced along the first direction, the M thin gate lines are equally spaced along the second direction, and the second direction is perpendicular to the first direction; The contact point is disposed at a position where the fine gate line intersects the sub-gate line.

Further, N solder contacts on each of the fine gate lines are arranged at equal intervals along the length direction of the thin gate lines.

Further, all of the solder contacts in the front electrode are distributed in an array of N rows x M columns.

Further, different shaped soldering contacts are alternately spaced on each of the fine grid lines.

Further, the shape of the solder contacts on one of the fine grid lines is the same, and the shapes of the solder contacts on the adjacent two fine grid lines are different from each other.

Further, the electrode unit includes a first electrode portion, a second electrode portion, and a third electrode portion spaced apart from each other in the first direction, and in the first direction, the length of the second electrode portion is greater than The length of one electrode portion and the third electrode portion.

Further, in a first direction, a ratio of lengths of the first electrode portion, the second electrode portion, and the third electrode portion is (0.4 to 0.6): 1: (0.4 to 0.6).

Further, in the first direction, the length of the second electrode portion is 0.6 to 1 mm, and the distance between the second electrode portion and the first electrode portion and the third electrode portion is 0.3 to 0.6 mm.

Compared with the prior art, in the front electrode of the crystalline silicon solar cell provided by the embodiment of the present invention, a fine gate line with a larger number of smaller widths is used instead of the main gate line in the prior art, and the overall shading area is smaller. The optical loss is reduced, and a larger number of fine grid lines are evenly distributed on the front surface of the solar cell, so that the current collected by the sub-gate lines can be more smoothly derived, reducing power loss; Large square, round or elliptical welded contacts increase the contact area of the solder joints and the height of the solder joints. When welding the solder ribbons, there is less problem of abnormal soldering of the solder ribbons and the battery sheets. Further, the back electrode is divided into electrode units that are in one-to-one correspondence with the solder contacts, and the electrode unit is segmented, which effectively reduces the amount of silver paste in the back electrode structure.

DRAWINGS

1 is a schematic structural view of a crystalline silicon solar cell according to an embodiment of the present invention;

2 is a schematic structural view of a front electrode in an embodiment of the present invention;

Figure 3 is an enlarged schematic view of a portion A of Figure 2;

4 is an exemplary illustration of an elliptical welding contact in an embodiment of the present invention;

5 is a schematic structural view of a back electrode in an embodiment of the present invention;

Fig. 6 is a schematic structural view of an electrode unit in an embodiment of the present invention.

detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Examples of these embodiments are exemplified in the drawings. The embodiments of the invention illustrated in the drawings and described in the drawings are merely exemplary and the invention is not Limited to these embodiments.

In this context, it is also to be noted that in order to avoid obscuring the invention by unnecessary detail, only the structures and/or processing steps closely related to the solution according to the invention are shown in the drawings, and the Other details that are not relevant to the present invention.

As shown in FIG. 1 , this embodiment firstly provides a crystalline silicon solar cell mainly comprising a battery body 1 and a front electrode 2 located on the front surface of the battery body 1 and a back electrode 3 located on the back surface of the battery body 1 . The battery body 1 mainly uses a silicon wafer to prepare a PN junction battery formed by a texturing process, a diffusion process, and an etching process. The front electrode 2 and the back electrode 3 are mainly formed on both sides of the battery body 1 by a screen printing process for outputting the electric energy converted by the battery body 1.

Referring to FIG. 2 and FIG. 3, the front electrode 2 provided in this embodiment includes a plurality of sub-gate lines 10 spaced apart from each other in the first direction (such as the Y direction in FIG. 2) and arranged in parallel, along the second direction (as shown in FIG. 2 and FIG. A plurality of fine gate lines 20 spaced apart from each other and arranged in parallel in the X direction, and the plurality of sub-gate lines 10 and the plurality of fine gate lines 20 are electrically connected to each other. The sub-gate line 10 is mainly used to collect the photo-generated current generated by the solar cell, and the fine-gate line 20 is used to collect and output the current collected by the sub-gate line 10. Further, each of the fine gate lines 20 is further provided with a plurality of soldering contacts 30 spaced apart from each other, and the soldering contacts 30 are stacked on the fine gate lines 20 and electrically connected to the fine grid lines 20. Connected, the shape of the solder contact 30 includes a circle and a square. The soldering contact 30 is mainly used for soldering connection to the solder ribbon after the battery is fabricated. Specifically in this embodiment, on each of the fine grid lines 20, the circular and square solder contacts 30 are alternately spaced apart. Of course, in other embodiments, the differently shaped solder contacts 30 may also be arranged in any order.

The number of the sub-gate lines 10 may be selected from the range of 80 to 100, and the width may be selected to be in the range of 30 to 50 μm. The number M of the fine gate lines 20 can be selected in the range of 10 to 20, and the width D1 can be selected in the range of 0.10 to 0.25 mm. The number N of the soldering contacts 30 provided on each of the fine gate lines 20 may be selected to be in the range of 5 to 15, and the diameter R of the circular soldering contacts 30 may be selected in the range of 0.2 to 1 mm, and the soldering is required. The diameter R of the contact point 30 is larger than the width of the fine grid line 20, and the side length L1 of the square soldering contact 30 can be selected to be in the range of 0.2 to 1 mm, and the side length of the soldering contact 30 is larger than that of the thin gate line 20. width. In the present embodiment, the number of the sub-gate lines 10 is 90, the width of the sub-gate lines 10 is 40 μm; the number of the fine gate lines 20 is M=15, and the width D1 of the fine gate lines 20 is 0.2 mm; each fine gate The number of solder contacts 30 on line 20 is N = 10, the diameter R of the round solder contacts 30 is 0.8 mm, and the square solder contacts 30 are specifically square with a side length L1 of 0.8 mm.

The solder contacts 30 are stacked on the fine gate lines 20. Specifically, in preparation In the case of the surface electrode structure, the sub-gate line 10 and the fine gate line 20 are first prepared by a single printing process, and then the solder contact 30 is prepared on the fine gate line 20 by a secondary printing process.

In this embodiment, as shown in FIG. 2, the plurality of sub-gate lines 10 are arranged at equal intervals in a first direction (such as the Y direction in FIG. 2), and the M thin gate lines 20 are in a second direction ( Arranged at equal intervals in the X direction as in FIG. 2, the second direction is perpendicular to the first direction. Further, the soldering contact 30 is disposed at a position where the fine gate line 20 intersects the sub-gate line 10, and N soldering contacts 30 on each of the fine gate lines 20 along the thin grid line 20 is arranged at equal intervals in the longitudinal direction.

More specifically, in the present embodiment, as shown in FIG. 2, the arrangement pitch of the N solder contacts 30 on each of the fine gate lines 20 is equal, and therefore, in the entire front electrode structure, all the solder contacts 30 are provided. An array of N rows x M columns. Specifically, since the circular and square solder contacts 30 are alternately spaced on each of the fine gate lines 20, in the N rows x M columns of the solder contacts 30, the odd number of circular solder contacts 30, even behavior Square solder contacts 30; of course, it is also possible to provide a solder contact 30 with an even number of circular shapes and a solder contact 30 with an odd number of squares.

Further, in other embodiments, the shape of the solder contacts 30 disposed on one of the fine gate lines 20 may be the same, and the shapes of the solder contacts 30 on the adjacent two fine gate lines 20 are mutually Not the same. Specifically, the shape of the soldering contact 30 on the first thin gate line 20 may be circular, and the shape of the soldering contact 30 on the second thin grid line 20 may be square, that is, in the N rows×M columns. Among the soldered contacts 30, the odd-numbered columns are circular solder contacts 30, and the even-numbered columns are square solder contacts 30; of course, it can also be set as even-numbered circular solder contacts 30, and the odd-numbered columns are square. Welding contacts 30.

The front electrode of the crystalline silicon solar cell provided by the above embodiments can effectively reduce the light shielding area. Taking the square of the front surface of the solar cell of 156 mm×156 mm as an example, the shading area is calculated according to the front electrode of the existing three main grid and the front electrode structure provided by the embodiment of the present invention:

1. The front electrode structure of the existing three main grids. In the conventional structure of three 1.5mm wide main gate lines and 90 40μm sub grid lines, the main gate lines can be designed in a hollow form to reduce the silver paste used for printing, but all areas of the main grid will still be soldered to a width of about 1.5 mm during soldering. The welding strip blocks the sunlight. Therefore, the shielding area of the sun at the main grid is 1.5 mm × 3 × 156 mm = 702 mm ² ; the shielding area of the sub grid and the four frames is 0.04 mm × (90 + 2) × (153.5 mm - 1.5 mm × 3) + 2 ×153.5 mm × 0.04 mm = 560.6 mm ² . The total occlusion area of the conventional three-main gate front electrode is 1262.6 mm ² .

2. The front electrode structure provided by the embodiment of the invention. According to a specific example, the number of sub-gate lines is 90, and the width thereof is 40 μm; the number of fine gate lines is 15 and the width thereof is 0.2 mm; each fine gate line The number of solder contacts on the top is ten, the shape of the solder contacts is half round, the diameter R is 0.8 mm, and the other half is square, and its side length is 0.8 mm. then:

a, 15 fine grid lines to the sun blocking area: 0.2mm × 15 × 156mm = 468mm ² ;

b. The obstruction of the sun by the sub-gate line and the four frames is: 0.04 mm × (90 + 2) × (153.5 mm - 0.2 mm × 10) + 0.04 mm × 2 × 153.5 mm = 566.12 mm ² ;

c. The circular pattern of 0.8mm diameter except the fine grid line blocks the sunlight:

[π × 0.4 ² mm ² - (0.8 mm - 0.2 mm) × 0.04 mm - π × 0.4 ² mm ² × 29 ° × 2 ÷ 360 ° - 0.2 × 0.4 × sin14.5] × 75 = 28.32 mm ² ;

d. The occlusion of the square pattern of 0.8 mm side length except the fine grid line is: (0.8 mm-0.2 mm) × 0.8 mm × 75 = 36 mm ² ;

The total area of the above ^{^{occlusion: 468mm 2 + 566.12mm 2 + 28.32mm}} 2 + 36mm 2 = 1098.44mm 2. The front electrode provided by the embodiment of the invention has a reduced light-shielding area of 1262.6 mm ² -1098.44 mm ² =164.16 mm ² compared to the front electrode of the existing three-main gate.

In still other embodiments, reference is made to the front side electrode as provided above, wherein the solder contact 30 can also be designed to be elliptical. That is, the shape of the welding contact 30 includes an ellipse and a circle, or includes an ellipse and a square, and may also include an ellipse and a circle as well as a square, an ellipse and a circle, and a square at each of the fine grid lines 20. The upper alternate interval settings are set in any order. Specifically, as the elliptical solder contact 30 shown in FIG. 4, the elliptical solder contact 30 is also disposed at a position where the thin gate line 20 intersects the sub-gate line 10. The long side of the elliptical shape is the same as the direction in which the thin grid line 20 extends, and the short side of the elliptical shape is the same as the direction in which the sub-gate line 10 extends. The length of the short side of the elliptical shape may be selected to be in the range of 0.2 to 1 mm, and the length L2 of the short side of the solder contact 30 is required to be larger than the width D1 of the thin gate line 20.

Further, referring to FIG. 5 and FIG. 6, the back electrode 3 in this embodiment includes N×M electrode units 31, that is, the number of the electrode units 31 and the soldering contacts 30 are equal, and the electrodes are The unit 31 has a one-to-one correspondence with the welding contacts 30, and the lengths of the electrode units 31 in the first direction (such as the Y direction in FIG. 5) and the second direction (in the X direction in FIG. 5) are not less than The length of the soldering contact in the corresponding direction. Specifically, if the soldering contact 30 is circular, the length of the electrode unit 31 in the first direction and the second direction is not less than the diameter of the circular soldering contact 30, respectively; if the soldering contact 30 is elliptical The length of the electrode unit 31 in the first direction is not less than the long axis of the elliptical solder contact 30, and the length in the second direction is not less than the short axis of the elliptical solder contact 30; if the solder contact 30 Square, the length of the electrode unit 31 in the first direction and the second direction is not less than the square solder contact 30, respectively. The length in the corresponding direction.

Wherein, as shown in FIG. 6, the electrode unit 31 includes the first electrode portion 311, the second electrode portion 312, and the third electrode portion 313 spaced apart from each other in the first direction, and in the first direction, The length of the second electrode portion 312 is greater than the lengths of the first electrode portion 311 and the third electrode portion 313, respectively. In a preferred embodiment, the ratio of the lengths of the first electrode portion 311, the second electrode portion 312, and the third electrode portion 312 in the first direction is L21: L22: L23 = (0.4 - 0.6): 1 : (0.4 to 0.6). The length L21 of the second electrode portion 312 may be selected to be 0.6 to 1 mm, and the distances D21 and D22 between the second electrode portion 312 and the first electrode portion 311 and the third electrode portion 313 may be selected to be 0.3. ~0.6mm. Among them, L21 and L23 can be selected as equal values, and D21 and D22 can be selected as equal values. Specifically, in this embodiment, the values of the respective parameters are as follows: L21=L23=0.5mm, L22=1mm, D21=D22=0.5mm; the length L24 of the electrode unit 31 in the second direction and the soldering contact 30 The diameter is equal, that is, L24 = 0.8mm.

The back electrode of the existing three-main grid solar cell generally comprises three columns, each column comprising three electrode blocks having a size of 21 mm x 3 mm, and the overall area of the back electrode is: 21 mm x 3 mm x 9 = 567 mm ² .

The back electrode structure provided by the above specific embodiment of the present invention includes 10×15=150 electrode units, the width of the electrode unit is L24=0.8 mm, the length is L21+L22+L23=2 mm, and the overall area of the back electrode is: 2 mm × 0.8 mm × 150 = 240 mm ² .

The back electrode provided by the embodiment of the present invention has an overall area reduced by 567 mm ² -240 mm ² = 327 mm ² compared with the back electrode of the existing three main grid solar cell, and under the same screen printing process, the silver paste The dosage is reduced by more than 50%, which greatly reduces the cost.

In summary, in the front electrode of the crystalline silicon solar cell provided by the above embodiment, a larger number of fine gate lines with smaller widths are used instead of the main gate lines in the prior art, and the overall shading area is smaller and reduced. Light loss, and a larger number of fine grid lines are evenly distributed on the front side of the solar cell, so that the current collected by the sub-gate line can be more smoothly derived, reducing power loss; in addition, the laminated area on the fine grid line is larger. The square or round or elliptical welding contacts increase the contact area of the solder joints and the height of the solder joints. When soldering the solder ribbon, there is less problem of abnormal soldering of the solder ribbon and the battery. Further, the back electrode is divided into electrode units that are in one-to-one correspondence with the solder contacts, and the electrode unit is segmented, which effectively reduces the amount of silver paste in the back electrode structure.

It should be noted that, in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply such entities or operations. There is any such actual relationship or order between them. Moreover, the terms "including", "comprising" or "comprising" or any other variants are intended to encompass a non-exclusive inclusion, such that Programs, methods, articles, or equipment include not only those elements, but also other elements not specifically listed, or elements that are inherent to such a process, method, article, or device. An element that is defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device that comprises the element.

The above description is only a specific embodiment of the present application, and it should be noted that those skilled in the art can also make several improvements and retouchings without departing from the principles of the present application. It should be considered as the scope of protection of this application.

Claims

A crystalline silicon solar cell includes a battery body and a front electrode on a front surface of the battery body and a back electrode on a back surface of the battery body, wherein

The front surface electrode further includes M thin gate lines which are arranged at intervals in the second direction, and the fine gate lines are electrically connected to the sub-gate lines, and the width of the fine gate lines is 0.10-0.25 mm; M=10～20; wherein each fine grid line is further provided with N soldering contacts spaced apart from each other, the soldering contact stack is disposed on the fine grid line and electrically connected to the fine grid line The shape of the soldering contact is two or more of a square shape, a circular shape, and an elliptical shape, and the length of the side length of the square, the diameter of the circle, or the short side of the ellipse is 0.2 to 1 mm, respectively. And the length of the side of the square, the diameter of the circle or the length of the short side of the ellipse are respectively greater than the width of the fine grid line; wherein, N = 5 to 15;

The back electrode includes N×M electrode units, and the electrode unit has a one-to-one correspondence with the soldering contacts, and the lengths of the electrode units in the first direction and the second direction are not less than the soldering contacts respectively. Corresponding to the length in the direction.
The crystalline silicon solar cell of claim 1, wherein the solder contact is formed on the fine gate line by a secondary printing process.
The crystalline silicon solar cell of claim 1 , wherein the plurality of sub-gate lines are equally spaced along a first direction, and the M fine gate lines are equally spaced along a second direction, the second direction being The first direction is perpendicular to each other; the soldering contact is disposed at a position where the fine gate line intersects the sub-gate line.
The crystalline silicon solar cell of claim 3, wherein the N solder contacts on each of the fine gate lines are equally spaced along the length of the thin gate lines.
The crystalline silicon solar cell of claim 4, wherein all of the solder contacts in the front side electrode are distributed in an array of N rows x M columns.
The crystalline silicon solar cell of claim 4, wherein the solder contacts of different shapes are alternately spaced on each of the fine grid lines.
The crystalline silicon solar cell of claim 4, wherein the solder contacts on one of the fine gate lines have the same shape, and the shapes of the solder contacts on the adjacent two fine grid lines are different from each other.
The crystalline silicon solar cell of claim 1, wherein the electrode unit includes a first electrode portion, a second electrode portion, and a third electrode portion spaced apart from each other in a first direction, and in a first direction, The length of the second electrode portion is greater than the length of the first electrode portion and the third electrode portion, respectively.
The crystalline silicon solar cell according to claim 8, wherein a ratio of lengths of the first electrode portion, the second electrode portion, and the third electrode portion in the first direction is (0.4 to 0.6): 1: (0.4 to 0.6).
The crystalline silicon solar cell according to claim 9, wherein the second electrode portion has a length of 0.6 to 1 mm in the first direction, and the second electrode portion and the first electrode portion and the third electrode portion The distance between the intervals is 0.3 to 0.6 mm.
The crystalline silicon solar cell according to claim 3, wherein the electrode unit includes the first electrode portion, the second electrode portion, and the third electrode portion spaced apart from each other in the first direction, and in the first direction, The length of the second electrode portion is greater than the length of the first electrode portion and the third electrode portion, respectively.
The crystalline silicon solar cell according to claim 11, wherein a ratio of lengths of the first electrode portion, the second electrode portion, and the third electrode portion in the first direction is (0.4 to 0.6): 1: (0.4 to 0.6).
The crystalline silicon solar cell according to claim 12, wherein the second electrode portion has a length of 0.6 to 1 mm in the first direction, and the second electrode portion and the first electrode portion and the third electrode portion The distance between the intervals is 0.3 to 0.6 mm.
The crystalline silicon solar cell of claim 4, wherein the electrode unit includes the first electrode portion, the second electrode portion, and the third electrode portion spaced apart from each other in the first direction, and in the first direction, The length of the second electrode portion is greater than the length of the first electrode portion and the third electrode portion, respectively.
The crystalline silicon solar cell according to claim 14, wherein a ratio of lengths of the first electrode portion, the second electrode portion, and the third electrode portion in the first direction is (0.4 to 0.6): 1: (0.4 to 0.6).
The crystalline silicon solar cell according to claim 15, wherein the second electrode portion has a length of 0.6 to 1 mm in the first direction, and the second electrode portion and the first electrode portion and the third electrode portion The distance between the intervals is 0.3 to 0.6 mm.
The crystalline silicon solar cell according to claim 6, wherein the electrode unit includes the first electrode portion, the second electrode portion, and the third electrode portion spaced apart from each other in the first direction, and in the first direction, The length of the second electrode portion is greater than the length of the first electrode portion and the third electrode portion, respectively.
The crystalline silicon solar cell according to claim 17, wherein the ratio of the lengths of the first electrode portion, the second electrode portion, and the third electrode portion in the first direction is (0.4 to 0.6): 1: (0.4 to 0.6).
The crystalline silicon solar cell according to claim 18, wherein the second electrode portion has a length of 0.6 to 1 mm in the first direction, and the second electrode portion and the first electrode portion and the third electrode portion The distance between the intervals is 0.3 to 0.6 mm.