TW201413984A - Solar cell with inclined finger electrodes - Google Patents

Abstract

A solar cell includes a cell body, one or multiple bus electrodes and multiple finger electrodes. The cell body converts light into electricity and generates charges. The bus electrodes are formed on a front side of the cell body. The finger electrodes are formed on the front side of the cell body and electrically connected to the bus electrodes. An included angle between the finger electrode and the bus electrode is unequal to 90 degrees. The finger electrodes and the bus electrodes collect the charges for output.

Description

Solar cell with inclined finger electrodes

This invention relates to a solar cell, and more particularly to a solar cell having a tilted finger electrode.

A solar cell is an energy-converting photovoltaic element that converts light energy into electrical energy after being irradiated by sunlight. This photoelectric element is called a solar cell. From a physics point of view, some people call it Photovoltaic (PV) batteries.

Conventional solar cells are manufactured by first providing a substrate and then performing chemical vapor deposition (such as PECVD) on the germanium substrate to form an anti-reflective layer, followed by screen printing and co-firing. An electrode is formed on the anti-reflection layer and the electrode penetrates the anti-reflection layer to be electrically connected to the germanium substrate.

The front electrode of a conventional solar cell typically includes two bus bar electrodes and a plurality of finger electrodes. For a long time, the finger electrode and the bus bar electrode are in an orthogonal state. Therefore, when the longitudinal direction of the bus bar electrode is regarded as the vertical direction, the longitudinal direction of the finger electrode is the horizontal direction. This unwritten rule limits the design of solar cells and does not improve the photoelectric conversion efficiency of solar cells.

It is an object of the present invention to provide a solar cell having a tilted finger electrode that increases current collection efficiency.

To achieve the above object, the present invention provides a solar cell including A battery body, one or more bus bar electrodes, and a plurality of finger electrodes. The battery body converts light energy into electrical energy to generate a plurality of charges. The bus bar electrodes are formed on one of the front faces of the battery body. The finger electrode is formed on the front surface of the battery body and electrically connected to the bus bar electrode. The angle between the finger electrode and the bus bar electrode is not equal to 90 degrees, and the finger electrode and the bus bar electrode collect a plurality of charges for output. .

With the above embodiment of the present invention, the length of the inclined finger electrode per unit area can be made longer than the length of the conventional horizontal finger electrode without changing the number of the finger electrodes, thereby increasing the current collecting efficiency. . In addition, the finger electrodes can also have different design parameters such that the sum of the lengths of all the points on the front side of the solar cell reaching the finger electrodes and/or the bus bar electrodes is minimized, improving the efficiency of the solar cell. In addition, since the height of the finger electrode is generally higher than that of the bus bar electrode, the inclination direction adjustment of the finger electrode can be parallel to the incident direction of the sunlight by the angle adjustment of the finger electrode, and can also be according to the shape of various buildings. Make appropriate adjustments to reduce the effect of shading and improve power generation efficiency.

In order to make the above description of the present invention more comprehensible, a preferred embodiment will be described below in detail with reference to the accompanying drawings.

1 shows a top view of a solar cell 1 in accordance with an embodiment of the present invention. Figure 2 shows a bottom view of a solar cell 1 in accordance with an embodiment of the present invention. 3A and 3B show cross-sectional views along lines 3A-3A and 3B-3B of Fig. 1, respectively. As shown in FIG. 1 to FIG. 3B, the solar cell 1 of the present embodiment includes a battery body 10 and one or more bus bar electrodes 20 . And a plurality of finger electrodes 30. The solar cell can be a single crystal, polycrystalline or thin film solar cell.

The battery body 10 is capable of converting light energy into electrical energy to generate a plurality of charges. In this embodiment, the battery body 10 includes a substrate 11 including a first type semiconductor layer 11A and a second type semiconductor layer 11B. For example, a P-type germanium substrate (as a second-type semiconductor layer) may be used to form an N-type semiconductor layer (as an N-type semiconductor layer) by doping; or, a variety of patterns may be used. The deposition technique, layer by layer, allows P-type or N-type materials to grow up.

In addition, the solar cell 1 further includes an anti-reflection layer 12 on the first type semiconductor layer 11A of the substrate 11, and one or more bus bar electrodes 20 and a plurality of finger electrodes 30 penetrate the anti-reflection layer 12 and are electrically connected to the first A type semiconductor layer 11A. The anti-reflection layer 12 provides an anti-reflection effect, and light incident on the anti-reflection layer 12 is not reflected to improve the utilization of light.

In the present example, three bus bar electrodes 20 are taken as an example. However, the present invention is not limited thereto, and the bus bar electrodes 20 may be one, two, four or other numbers. The bus bar electrode 20 is formed on one front surface 10A of the battery body 10.

The finger electrode 30 is formed on the front surface 10A of the battery body 10 and electrically connected to one or more bus bar electrodes 20. The angle Ang between the finger electrode 30 and the bus bar electrode 20 is not equal to 90 degrees, and multiple fingers The shaped electrode 30 and the one or more bus bar electrodes 20 collect a plurality of charges for output. It is worth noting that the angle Ang can be between 0 and 90 degrees, including 0 degrees, but not 90 degrees.

In addition, the solar cell 1 may further include one or more back electrodes 40 and a back metal layer 50. In the present example, three back electrodes are exemplified, however, the present invention is not limited thereto. The number of back electrodes may be one, two or four, and the like. The back surface electrode 40 is formed on one back surface 10B of the battery body 10 and is electrically connected to the second type semiconductor layer 11B. The back surface 10B is located on the opposite side of the front surface 10A.

The back metal layer 50 is formed on the back surface 10B of the battery body 10, and one or more back electrodes 40 penetrate the back metal layer 50 and are electrically connected to the second type semiconductor layer 11B.

In an embodiment of the invention, the angle Ang is between 89 degrees and 74 degrees, and particularly the angle Ang is between 88 degrees and 86 degrees.

In Fig. 1, the angle Ang is equal to 80 degrees, and the finger electrodes 30 are all inclined in the same direction, that is, from the upper left to the lower right.

In addition, the solar cell 1 may further include a peripheral electrode 60 formed on the front surface 10A of the battery body 10 and surrounding and electrically connected to the bus bar electrode 20 and the plurality of finger electrodes 30 to facilitate charge collection and transmission. In the present example, the peripheral electrode 60 is substantially parallel to the periphery of the battery body 10. Therefore, some portions of the peripheral electrode 60 are parallel to the bus bar electrode 20, and some portions of the peripheral electrode 60 are perpendicular to the bus bar electrode 20, as shown in FIG. Show.

It should be noted that the line 3A-3A of FIG. 1 is cut to the bus bar electrode 20 and the peripheral electrode 60, but is not cut to the finger electrode 30, and the line 3B-3B of FIG. 1 is cut to the bus bar electrode 20 and the periphery. Electrode 60 and finger electrode 30. So Figures 3A and 3B will be slightly different, as shown.

4 to 12 show top views of solar cells of various variations of Fig. 1. As shown in FIG. 4, the angle Ang is equal to 75 degrees, and the finger electrodes 30 are all inclined toward the same direction. As shown in FIG. 5, the angle Ang is equal to 85 degrees, and the finger electrodes 30 are all inclined toward the same direction.

As shown in FIG. 6, the angle Ang is equal to 88 degrees (also referred to as 92 degrees), and the finger electrodes 30 are all symmetric based on the intermediate bus bar electrode 20, so that the intermediate bus bar electrode 20 and the plurality of finger electrodes 30 are provided. Form an arrow pattern. That is, the finger electrode 30 of the left half is inclined from the lower left to the upper right, and the finger electrode 30 of the right half is inclined from the upper left to the lower right, and the finger electrode 30 of the right half faces the middle bus electrode. After 20 mirroring, the finger electrode 30 of the right half can be obtained. In Fig. 6, the solar cell can be made directional in appearance, and there is no confusion in assembly. Generally, when a plurality of solar cells are connected in series and in parallel in a module factory, especially when the assembly process is interrupted, the assembler can learn the directionality by using the arrow symbol, and can overcome the unevenness of the characteristics of the solar cell during manufacture. The problem. In addition, it is also visually more aesthetically pleasing or special.

As shown in FIG. 7, the solar cell of the present example has two bus bar electrodes 20. As shown in FIG. 8, the solar cell of the present example has four bus bar electrodes 20. This means that the tilted finger electrode can be applied to any occasion, meeting the design requirements of each occasion.

When a plurality of solar cells 1 are connected in series, the bus bar electrode 10A on the front side of the battery body 10 is connected to the back electrode 50 of an adjacent one of the solar cells, and so on, to form a solar cell module. Let the entire solar cell module look like a slanted finger Electrode, if the solar cell of Figure 6 is used, the directionality exhibited by the arrow symbol is more obvious and uniform, placed on the building, and can also indicate the desired orientation, such as pointing the arrow to the north, south, east, west, and the like.

As shown in FIG. 9, this example is similar to FIG. 1, except that the plurality of finger electrodes 30 are staggered with each other. The staggered angle may be any angle as long as the finger electrode 30 is not made perpendicular to the bus bar electrode 20. This design also contributes to efficiency.

As shown in FIG. 10, the present example is similar to FIG. 1, except that the finger electrodes 30 are parallel to the bus bar electrodes 20, and the solar cell 1 further includes a plurality of transverse electrodes 70 electrically connected to the bus bar electrodes 20 and The finger electrode 30. The traverse electrode 70 is also positioned on the front surface of the battery body 10 and penetrates the anti-reflection layer. This design also contributes to efficiency.

As shown in Fig. 11, the present example is similar to Fig. 1, except that the finger electrodes 30 are horizontal, but the bus bar electrodes 20 are double inclined. The shape of the back electrode 50 may be such a double-inclined shape or a vertical shape. Such a design can also achieve the effect of the present invention, increasing the total length of the bus bar electrode or the finger electrode, and improving the efficiency.

As shown in Fig. 12, the present example is similar to Fig. 6, except that all of the finger electrodes 30 are arranged in four blocks in an inclined manner. Such a design can also achieve the effect of the present invention, increasing the total length of the bus bar electrode or the finger electrode, and improving the efficiency.

With the above solar cell of the present invention, the inclined finger electrode per unit area can be made without changing the number of finger electrodes The length is longer than the length of the conventional horizontal finger electrode, so the current collecting efficiency can be increased. According to the calculation results, the total length of the finger electrodes with an inclination angle of 87 degrees is increased by 0.9%, and the total length of the finger electrodes having an inclination angle of 85 degrees is increased by 0.88%, and the inclination angle is 80 degrees. The total length of the finger electrodes was increased by 0.9%, the total length of the finger electrodes having an inclination angle of 75 degrees was increased by 0.89%, and the total length of the finger electrodes using the inclination of 88 degrees similar to that of Fig. 12 was increased by 1.2%. In addition, the finger electrodes can be made with different design parameters such that the sum of the lengths of all the points on the front side of the solar cell reaching the finger electrodes and/or the bus bar electrodes is minimized, improving the efficiency of the solar cell. In addition, since the height of the finger electrode is generally higher than that of the bus bar electrode, the inclination direction adjustment of the finger electrode can be parallel to the incident direction of the sunlight by the angle adjustment of the finger electrode, and can also be according to the shape of various buildings. Make appropriate adjustments to reduce the effect of shading and improve power generation efficiency. Furthermore, the inclined finger electrodes can also be used to indicate the directionality of the solar cell during manufacture, so that the assembler or the customer can make reference, especially for an unfamiliar assembler or customer to easily assemble and implement.

The specific embodiments of the present invention are intended to be illustrative only and not to limit the invention to the above embodiments, without departing from the spirit of the invention and the following claims. The scope of the invention and the various changes made are within the scope of the invention.

Ang‧‧‧ angle

1‧‧‧Solar battery

Lines 3A-3A and 3B-3B‧‧

10‧‧‧ battery body

10A‧‧‧ positive

10B‧‧‧Back

11‧‧‧Substrate

11A‧‧‧first type semiconductor layer

11B‧‧‧Second type semiconductor layer

12‧‧‧Anti-reflective layer

20‧‧‧ Bus bar electrode

30‧‧‧Finger electrode

40‧‧‧Back electrode

50‧‧‧Back metal layer

60‧‧‧ peripheral electrodes

70‧‧‧cross electrodes

1 shows a top view of a solar cell in accordance with an embodiment of the present invention.

2 shows a bottom view of a solar cell in accordance with an embodiment of the present invention.

3A and 3B show cross-sectional views along lines 3A-3A and 3B-3B of Fig. 1, respectively.

4 to 12 show top views of solar cells of various variations of Fig. 1.

Ang‧‧‧ angle

1‧‧‧Solar battery

Lines 3A-3A and 3B-3B‧‧

10‧‧‧ battery body

10A‧‧‧ positive

20‧‧‧ Bus bar electrode

30‧‧‧Finger electrode

60‧‧‧ peripheral electrodes

Claims (15)

A solar cell comprising: a battery body for converting light energy into electrical energy to generate a plurality of charges; one or more bus bar electrodes formed on a front surface of the battery body; and a plurality of finger electrodes formed on the The front surface of the battery body is electrically connected to the one or more bus bar electrodes, and an angle between the finger electrode and the bus bar electrode is not equal to 90 degrees, and the plurality of finger electrodes are opposite to the one or more The bus bar electrodes collect the plurality of charges for output. The solar cell of claim 1, wherein the battery body comprises a substrate, the substrate comprises a first type semiconductor layer and a second type semiconductor layer, and the solar cell further comprises: an anti-reflection layer, On the first type semiconductor layer of the substrate, the one or more bus bar electrodes and the plurality of finger electrodes penetrate the anti-reflection layer and are electrically connected to the first type semiconductor layer. The solar cell of claim 1, further comprising: one or more back electrodes formed on a back surface of the battery body and electrically connected to the second type semiconductor layer; and a back metal layer formed On the back surface of the battery body, the one or more back electrodes penetrate the back metal layer and are electrically connected to the second type semiconductor layer. The solar cell of claim 1, wherein the included angle is between 89 degrees and 74 degrees. The solar cell of claim 1, wherein The angle is between 88 and 86 degrees. The solar cell of claim 1, wherein the angle is equal to 88 degrees, 85 degrees, 80 degrees or 75 degrees. The solar cell of claim 1, wherein the one or more bus bar electrodes are two bus bar electrodes. The solar cell of claim 1, wherein the one or more bus bar electrodes are three bus bar electrodes. The solar cell of claim 1, wherein the one or more bus bar electrodes are four bus bar electrodes. The solar cell of claim 1, wherein the one or more bus bar electrodes are three bus bar electrodes, and the plurality of finger electrodes are all inclined in the same direction. The solar cell of claim 1, wherein the one or more bus bar electrodes are three bus bar electrodes, and the plurality of finger electrodes are all based on an intermediate confluence in the middle of the three bus bar electrodes. The electrodes are symmetrically arranged such that the intermediate bus bar electrode forms an arrow pattern with the plurality of finger electrodes. The solar cell of claim 1, further comprising: a peripheral electrode formed on the front surface of the battery body, and surrounding and electrically connected to the one or more bus bar electrodes and the plurality of fingers electrode. The solar cell of claim 1, wherein the plurality of finger electrodes are staggered with each other. The solar cell of claim 1, wherein The finger electrode is parallel to the one or more bus bar electrodes. The solar cell of claim 14, further comprising: a plurality of transverse electrodes electrically connected to the one or more bus bar electrodes and the plurality of finger electrodes.