CN103887350A - Matrix back electrodes for crystalline silicon solar cell - Google Patents

Abstract

The invention discloses a matrix-type back electrode of a crystalline silicon solar cell. The crystalline silicon solar cell is a polycrystalline 156 battery sheet. The back electrode has fifteen sections, and the back electrodes of the fifteen sections are arranged in a matrix of five rows and three columns. One row of back electrodes is located in the middle of the back of the cell, and the other two rows of back electrodes are each 52 mm away from the middle row of back electrodes. Each section of the back electrode is in the shape of a vertical strip, and the edge of each section of the back electrode is connected with a number of frame lines. The frame lines are evenly distributed around the back electrode at intervals, and the edge of the back electrode and the frame line are in contact with the back electric field. The matrix-type back electrode of the crystalline silicon solar cell reduces the consumption of back silver, and is more in contact with the back aluminum. Well, the printing area of the back field is increased, the current and voltage are better improved, and at the same time, the problem of the superposition of the back electrode and the back electric field is better controlled.

Description

Crystalline silicon solar cell matrix back electrode

technical field

The invention belongs to the field of solar cell structures, and in particular relates to a back electrode structure of polycrystalline 156 cells.

Background technique

A solar cell is a device that directly converts light energy into electrical energy. Due to its cleanliness, pollution-free, inexhaustible and inexhaustible, it has attracted more and more attention.

At present, silicon solar cells are widely used, and its manufacturing process has also been standardized. The main steps are: chemical cleaning and surface structuring (texturing)-diffusion junction-peripheral etching-deposition of anti-reflection film-screen printing-sintering . Among them, the screen printing first prints the back electrode, the paste is Ag paste, the back electric field is printed after drying, the paste is Al paste, and the front electrode is printed after being turned over by a flipper after drying, and the paste is Ag paste. For polycrystalline 156 cells, there are generally three back electrodes, the distance between the two edge electrodes and the edge of the cell is 26mm, and the middle one is located in the middle of the cell, that is, the distance from the two edges is 52mm. The main function of the back electrode is to provide a welding point for the component part, which is beneficial to the output of the photo-generated current.

However, with this method, the unit consumption of the Ag paste for the back electrode is too large, and the current wet weight control range is 0.07-0.08g, and because the area of the back electrode is too large, the printing area of the back field is small, which is not conducive to the battery. The open circuit voltage and short circuit current of the chip, moreover, the contact and superposition of the back electrode and the back field are not good enough.

Contents of the invention

In order to solve the above problems, the present invention provides a matrix-type back electrode of a crystalline silicon solar cell, which reduces the consumption of back silver; has better contact with the back aluminum and increases the printing of the back field The area is better to increase the current and voltage; at the same time, it also better controls the problem of the superposition of the back electrode and the back electric field.

The technical scheme that the present invention adopts in order to solve its technical problem is:

A matrix-type back electrode of a crystalline silicon solar cell. The crystalline silicon solar cell is a polycrystalline 156 battery sheet. The back electrode has fifteen segments, and the fifteen segments are arranged in a matrix of five rows and three columns. The electrode is located in the middle of the back of the cell, and the other two rows of back electrodes are 52 mm away from the middle row of back electrodes (referring to the distance between the center lines of each row of back electrodes). A number of frame lines are connected to the edges, and the frame lines evenly cover the periphery of the back electrode at intervals, and the edges of the back electrode and the frame lines are in contact with the back electric field.

The further technical scheme that the present invention adopts in order to solve its technical problem is:

Further, each section of the back electrode is a rectangular vertical strip with a length of 18 mm and a width of 2.3 mm, and the distance between the back electrodes of the same row is 12 mm, and the back electrodes at the first and last ends of each row of back electrodes are connected to the The spacing between the edges of the cells is 6 mm each.

Furthermore, a column of frame lines is evenly distributed on the left and right sides of each section of the back electrode, and each column of frame lines is composed of eighteen frame lines with a mutual interval of 0.5 mm, and the frame lines located at the head and tail ends Each is 0.25 mm away from the head and tail ends of the back electrode; a row of frame lines is evenly distributed at the head and tail ends of each section of the back electrode, and each line of frame lines is composed of three frame lines with a mutual interval of 0.4 mm. The frame lines at the left and right ends are respectively aligned with the left and right ends of the back electrode; the frame lines are rectangular frame lines with a length of 1 mm and a width of 0.5 mm.

The beneficial effects of the present invention are: the matrix type back electrode of the crystalline silicon solar cell of the present invention mainly divides the back electrode into fifteen sections, and the back electrodes of the fifteen sections are arranged in a matrix of five rows and three columns, and each section of the back electrode There are several frame lines connected to the edges, and the edges and frame lines of the back electrode are in contact with the back electric field, so it has the following advantages:

1) Low unit consumption: Under the same printing parameter settings, the unit consumption range of the screen printing of the present invention is 0.03-0.04g, while the unit consumption range of the existing linear electrode is 0.06-0.08g, and the unit consumption is reduced by about 40% ;

2) The opening voltage and current of the battery are improved: due to the use of matrix electrodes, the printing area of the back electrode is reduced, thereby increasing the passivation area of the back electric field, and the opening voltage and current of the battery are improved;

3) Better contact between the back electrode and the back electric field: Since there is a circle of densely distributed frame lines around each segment of the back electrode, the contact between the back electrode and the back electric field is better.

Description of drawings

Fig. 1 is a structural representation of the present invention;

FIG. 2 is a schematic diagram of the structure of each segment of the back electrode and its surrounding frame lines in the present invention.

Detailed ways

The specific implementation of the present invention is described below through specific examples, and those skilled in the art can easily understand the advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented in other different ways, that is, various modifications and changes can be made without departing from the disclosed scope of the present invention.

Embodiment: A matrix-type back electrode of a crystalline silicon solar cell, the crystalline silicon solar cell is a polycrystalline 156 solar cell, the back electrode 1 has fifteen segments, and the fifteen segment back electrodes are arranged in a matrix of five rows and three columns One row of back electrodes is located in the middle of the back of the cell, and the other two rows of back electrodes are each 52 mm away from the middle row of back electrodes (referring to the distance between the center lines of each row of back electrodes). A plurality of frame lines 2 are connected to the edges of the segment back electrodes, and the frame lines are evenly distributed around the back electrode at intervals, and the edges of the back electrodes and the frame lines are in contact with the back electric field.

The back electrodes in each segment are rectangular vertical strips with a length of 18 mm and a width of 2.3 mm, and the distance between the back electrodes of the same row is 12 mm, and the back electrodes at the first and last ends of each row of back electrodes are connected to the edge of the cell The pitches are each 6 mm.

A column of frame lines is evenly distributed on the left and right sides of each section of the back electrode, and each column of frame lines is composed of eighteen frame lines with a mutual interval of 0.5 mm, and the frame lines at the head and tail ends are respectively separated from the back electrode The first and last ends of each section of the back electrode are 0.25 mm; each row of the frame lines is evenly distributed at the head and tail ends of each section of the back electrode, and each line of frame lines is composed of three frame lines with an interval of 0.4 mm, and the frame lines at the left and right ends Each is aligned with the left and right ends of the back electrode; the frame lines are rectangular frame lines with a length of 1 mm and a width of 0.5 mm.

In the experiment, 200 pieces of silicon wafers from the same silicon ingot were selected, and 100 pieces were printed with the matrix back electrode screen and the existing linear back electrode screen respectively, and the unit consumption and electrical performance data were compared.

Experimental example: matrix back electrode of the present invention

Put the screen plate into the printing machine, install the scraper, ink return knife, and add slurry, adjust the printing parameters to ensure that the printed back electrode pattern is good, measure the wet weight, and the results are as follows:

sampling 1 2 3 4 5 average value wet weight (g) 0.033 0.035 0.037 0.036 0.034 0.035

The situation of measuring its electrical performance parameters under the conditions of AM1.5, light intensity 1000W, and 25°C is:

Voc (open circuit voltage) Isc (short circuit current) FF (fill factor) Eff (photoelectric conversion efficiency) 0.626 8.56 78.4 17.26%

Comparative example: The printing parameters remain unchanged, and the existing linear electrode is replaced by screen printing to make the existing linear electrode, and the wet weight is measured. The results are as follows:

sampling 1 2 3 4 5 average value wet weight (g) 0.062 0.062 0.061 0.063 0.063 0.062

The situation of measuring its electrical performance parameters under the conditions of AM1.5, light intensity 1000W, and 25°C is:

Voc (open circuit voltage) Isc (short circuit current) FF (fill factor) Eff (photoelectric conversion efficiency) 0.625 8.55 78.5 17.24%

It can be seen from the above experiments that the unit consumption of the present invention is reduced by about 40%, the open-circuit voltage Uoc and the short-circuit current Isc are slightly improved in terms of electrical performance parameters, and the efficiency is slightly higher by 0.02%. It can be seen that this invention not only greatly reduces the cost of the production process of solar cells, but also improves the conversion efficiency of solar cells to a certain extent.

Claims (3)

1. a crystal silicon solar energy battery matrix form back electrode, described crystal silicon solar energy battery is polycrystalline 156 cell pieces, it is characterized in that: described back electrode (1) has 15 sections, and 15 sections of back electrodes are the five-element's three column matrix shapes and arrange, one row back electrode is positioned in the middle of the cell piece back side, all the other two row back electrodes are separately apart from 52 millimeters of middle row back electrodes, every section of back electrode is all vertical bar shape, and the edge of every section of back electrode is all connected with some frame lines (2), the interruption-like back electrode periphery that is evenly covered with of described frame line, the edge of described back electrode contacts with back of the body electric field with described frame line.

2. crystal silicon solar energy battery matrix form back electrode as claimed in claim 1, it is characterized in that: every section of described back electrode be length be 18 millimeters and wide be the rectangle vertical bar shape of 2.3 millimeters, and the spacing between same column back electrode is 12 millimeters, in every row back electrode, is positioned at the head and the tail back electrode at two ends and the spacing at cell piece edge and does for oneself 6 millimeters.

3. crystal silicon solar energy battery matrix form back electrode as claimed in claim 2, it is characterized in that: the left and right sides of every section of described back electrode is evenly distributed with the described frame line of row separately, the frame line that every row frame line is all 0.5 millimeter by 18 spaces forms, and the frame line that is positioned at two ends is separately apart from 0.25 millimeter of the two ends of back electrode; The two ends of every section of described back electrode are evenly distributed with frame line described in a line separately, and the frame line that every row frame line is all 0.4 millimeter by three spaces forms, and the frame line that is positioned at left and right end separately with the left right-hand justified of back electrode; Described frame line be length be 1 millimeter and wide be the rectangle frame line of 0.5 millimeter.

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