JP2014236217A - Solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar cell.SOLUTION: In a solar cell including a substrate for solar cell having a first surface and a second surface, and a plurality of sets of electrode assemblies arranged on the first surface of the substrate for solar cell while separated from each other, each electrode assembly includes a bus bar electrode, a plurality of finger electrodes, a plurality of wire electrodes for connection, and a plurality of vertical finger electrodes.

Description

  The present invention relates to a solar cell, and more particularly to a solar cell that reduces electroluminescence.

  In the production process of solar cells, the quality can be ensured after the product is finally inspected. Defect items that need to be measured include material defects, sintering, manufacturing process contamination, microscopic cracks, circuit breaks, and the like. Electrical test methods can remove these defective products. However, the two defects, microscopic cracks and circuit breaks, have a very large effect on the stability and life of the product even if they do not have a large effect on the conversion efficiency. It needs to be detected.

  As the appearance measurement method, electroluminescence (EL) is most popular. When the forward current is applied to the solar cell, the EL emits near-infrared light like a light-emitting diode, and the intensity of the light is related to the magnitude of the input current and is also related to defects. When there is a defect, it can be seen that the defect exists because no light is emitted even if the current passes through the circuit.

  Description will be made with reference to the diagram of the prior art solar cell of FIG. 1A. Here, three bus bar electrodes 120 (Bus Bar Electrode) and a plurality of finger electrodes (Finger Electrode) 110 are arranged on the solar cell substrate 100. In this solar cell, disconnection occurs in the local region 1 of the front electrode structure of the solar cell due to the cause of the manufacturing process.

  Next, a description will be given with reference to an enlarged view of the local region 1 of the conventional solar cell structure of FIG. 1B. After applying the forward current to the solar cell, the solar cell should emit near-infrared light when the current originally passes, but the disconnection point 111 occurs in the local region 1, the path is too long, and the current is disconnected. The finger electrode 115 cannot emit infrared light because it cannot sufficiently flow to the portion 111. When the local region 1 was photographed with the infrared camera, a part of the finger electrode 115 was dark.

This EL measurement is currently an important quality metric for solar cells. Generally, the finger electrode 115 as a whole is darkened because the current path is always too long to reach the disconnection point 111 during the EL measurement of the finger electrode. Therefore, it is determined that the current collection efficiency is reduced, that is, there is an EL defect problem, and the entire solar cell is regarded as a defective product and discarded. However, the finger electrode 115 itself actually has a current collecting ability when the solar cell generates power.
Therefore, how to reduce the disconnection problem discovered during the EL measurement of the solar cell and further improve the current collection capability of the finger electrode is one important technical issue for the technical development of solar cell manufacturers.

  Therefore, in view of the above-mentioned problems of the prior art, the present invention maintains good solar cell quality under the premise that power generation efficiency is not lowered by reducing the problem of EL measurement failure caused by disconnection of the solar cell. It aims at providing the solar cell which has a specific effect.

The present invention provides a solar cell including a solar cell substrate having a first surface and a second surface, and a plurality of sets of electrode assemblies arranged separately from each other on the first surface of the solar cell substrate. To do.
Each electrode assembly is provided on the first surface of the solar cell substrate, a bus bar electrode provided on the first surface of the solar cell substrate, a plurality of finger electrodes arranged on both sides of the bus bar electrode, and a gap. At least one connecting wire electrode connected to the ends of at least two finger electrodes, provided on the first surface of the solar cell substrate, parallel to the bus bar electrode and between both ends of the finger electrodes. And at least one vertical finger electrode for connecting to at least two adjacent finger electrodes.

  Hereinafter, detailed features and advantages of the present invention will be described in detail in the embodiments. The contents make it possible for those skilled in the art to understand the technical contents of the present invention, and for those skilled in the art to practice the present invention, and based on the contents disclosed in this specification, the claims, and the drawings, those skilled in the art can easily perform the present invention. The objects and advantages of the present invention can be understood.

It is a figure which shows the structure of the solar cell of a prior art. 1B is a locally enlarged view of the structure of the prior art solar cell of FIG. 1A. FIG. It is a figure which shows one Example of the structure of the solar cell which concerns on this invention. It is a local enlarged view of the structure of the solar cell which concerns on this invention of FIG. 2A. It is a figure which shows the disconnection of the structure of the solar cell which concerns on this invention of FIG. 2B. It is a figure which shows the other Example of the structure of the solar cell which concerns on this invention. It is the local enlarged view of the structure of the solar cell which concerns on this invention of FIG. 3A. It is a figure which shows the further Example of the structure of the solar cell which concerns on this invention. It is a local enlarged view of the structure of the solar cell according to the present invention of FIG. 4A. It is a figure which shows the other Example of the structure of the solar cell which concerns on this invention. It is a local enlarged view of the structure of the solar cell according to the present invention of FIG. 5A. It is a figure which shows the further Example of the structure of the solar cell which concerns on this invention. It is a local enlarged view of the structure of the solar cell which concerns on this invention of FIG. 6A. It is a local enlarged view of the other Example of the structure of the solar cell concerning this invention. It is a local enlarged view of the other Example of the structure of the solar cell concerning this invention.

FIG. 2A is a diagram showing an embodiment of a front electrode structure of a solar cell according to the present invention. FIG. 2B is an enlarged view of the local region 2 of the structure of the solar cell according to the present invention of FIG. 2A.
This will be described with reference to FIGS. 2A and 2B. The solar cell according to the present invention includes a plurality of bus bar electrodes 120 (three bus bar electrodes 120 in this embodiment), a plurality of finger electrodes 110, a plurality of connecting wire electrodes 130, and a plurality of vertical finger electrodes 140. . The bus bar electrodes 120 are arranged on the solar cell substrate 100 with an interval. In essence, the solar cell structure in the embodiment of FIG. 2A includes three sets of electrode assemblies 3, 4, and 5, and the three sets of electrode assemblies 3, 4, and 5 Placed in isolation.
The electrode assemblies 3, 4, and 5 are a bus bar electrode 120 provided on the first surface of the solar cell substrate 100, a plurality of finger electrodes 110 arranged on both sides of the bus bar electrode 120, and a solar cell A plurality of connecting wire electrodes 130 provided on the first surface of the substrate 100, each connecting wire electrode 130 connecting to the ends of at least two finger electrodes 110, and the first surface of the solar cell substrate 100. A plurality of vertical finger electrodes 140 connected to at least two adjacent finger electrodes 110, each vertical finger electrode 140 being parallel to the bus bar electrode 120 and provided between both ends of the finger electrodes; 140 respectively.
As shown in FIG. 2A, both ends of the finger electrode 110 are connected to the bus bar electrode 120 and the connecting wire electrode 130, and the vertical finger electrode 140 is provided between both ends of the finger electrode 110. 140 is located between the bus bar electrode 120 and the connecting wire electrode 130. In this embodiment, adjacent finger electrodes to which each vertical finger electrode 140 and each connecting wire electrode 130 are connected are the same.

Comparing FIG. 2A and FIG. 2B with FIG. 1A and FIG. 1B of the prior art, the difference is that the electrode assemblies 3, 4, and 5 of this embodiment are spaced apart from each other, and a plurality From FIG. 2B of the enlarged view of the local region 2 of the solar cell structure, each vertical finger electrode 140 and a plurality of connecting wire electrodes 130 are added, and each vertical finger electrode 140 is connected to at least two finger electrodes 110. As can be seen, after adding the vertical finger electrode 140 and the connecting wire electrode 130, the current path during EL measurement can be shortened.
In this embodiment, the vertical finger electrode 140 and the bus bar electrode 120 have an angle of intersection of 0 degrees, that is, parallel to the bus bar electrode 120. In other embodiments, the vertical finger electrode 140 and the bus bar electrode 120 may have an angle of intersection of less than 45 degrees, that is, the vertical finger electrode 140 may be obliquely connected to both adjacent finger electrodes 110. .

Next, reference is made to the disconnection point 111 in FIG. 2C. After adding the vertical finger electrode 140 and the connecting wire electrode 130, the current path becomes shorter and there are more selectable paths. When the disconnection point 111 appears in the finger electrode 110, the current can reach the disconnection point 111 via the vertical finger electrode 140 and the connecting wire electrode 130 to emit light. Through the vertical finger electrode 140 and the connecting wire electrode 130 of the present invention, it can be found that the disconnection point 111 in the prior art can still emit light during the EL measurement.
Therefore, after adding the vertical finger electrode 140 and the connecting wire electrode 130, it is possible to reliably improve the problem that the disconnection portion 111 becomes dark in EL measurement. On the contrary, in this embodiment, the finger electrode 110 has a disconnection portion 111, and the current generated in the vicinity of the disconnection portion 111 after light irradiation is also applied to each electrode assembly 3 through the vertical finger electrode 140 and the connection wire electrode 130, Since it can be made to flow to 4 and 5 bus-bar electrodes 120, the present invention can also raise the efficiency of photovoltaic power generation.

  Each single electrode assembly can concentrate the current generated in the independently covered region on the bus bar electrode 120 via the finger electrode 110 therein. Since the electrode assemblies are isolated from each other, the current generated in the region covered by each electrode assembly does not flow to other regions. In addition, the bus bar electrodes 120 in the electrode assemblies 3, 4, and 5 are substantially parallel to each other. The center of the bus bar electrode 120 is at the center of the electrode assembly located.

  Adjacent electrode assemblies are separated from each other with a width d, and are electrode assemblies 3 and 4 as shown in FIG. 2B. The width d is 30 micrometers to 5,000 micrometers. Within this range, the solar cell does not experience a significant decrease in battery efficiency.

Next, FIG. 3A is a figure which shows the other Example of the structure of the solar cell based on this invention. FIG. 3B is an enlarged view of the local region 2 of the structure of the solar cell according to the present invention of FIG. 3A. This will be described with reference to FIGS. 3A and 3B.
The connection wire electrode 130 connects the two finger electrodes 110 to each other by connecting to the end of the adjacent finger electrodes 110. As shown in FIG. 3A, both ends of the finger electrode 110 are connected to the bus bar electrode 120 and the connecting wire electrode 130, and the vertical finger electrode 140 is provided between both ends of the finger electrode 110. Arranged between the bus bar electrode 120 and the connecting wire electrode 130. However, in this embodiment, adjacent finger electrodes to which each vertical finger electrode 140 and each connecting wire electrode 130 are connected are different. As shown in FIGS. 3A and 3B, the line width of each connection wire electrode 130 is 10 micrometers (μm) to 200 micrometers (μm). Two adjacent connecting wire electrodes 130 are separated from each other with a width d, and the width d is 30 micrometers to 5,000 micrometers.
In addition, regarding the embodiment of FIGS. 3A and 3B, the form formed after the connection of the plurality of connection wire electrodes 130 is linear, and regarding the other embodiments, a plurality of connection wires are used. The form formed after the connection of the electrode 130 can be a wave shape, a tooth shape (not shown), or other shapes. With respect to the connecting wire electrodes 130 having different shapes, they do not need to be at a fixed distance from each other, and it is only necessary to maintain the mutual distance within the range of the width d of the width d. The connecting wire electrode 130 and the bus bar electrode 120 have an intersection angle θ, and the intersection angle θ is 0 to 80 degrees.

  2A, 2B, 3A, and 3B are examples in which adjacent portions of two adjacent electrode assemblies are parallel to the bus bar electrode 120. FIG. In another embodiment, a method in which adjacent portions of two adjacent electrode assemblies 3 and 4 are not parallel to the bus bar electrode 120 can be employed.

  FIG. 4A is a diagram showing a further embodiment of the front electrode structure of the solar cell according to the present invention. FIG. 4B is a locally enlarged view of the solar cell structure according to the present invention of FIG. 4A. This will be described with reference to FIGS. 4A and 4B. In this embodiment, the adjacent portions of the two electrode assemblies 3 and 4 and the bus bar electrode 120 have an intersection angle θ, and the intersection angle θ can be 10 degrees.

  FIG. 5A is a diagram showing an embodiment of a front electrode structure of a solar cell according to the present invention. FIG. 5B is an enlarged view of the local region 2 of the solar cell structure according to the present invention of FIG. 5A. This will be described with reference to FIGS. 5A and 5B. The vertical finger electrodes 140 are disposed on both sides of the electrode assembly, and each vertical finger electrode 140 is connected to three finger electrodes, thereby connecting a part of the three finger electrodes 110 to each other.

  FIG. 6A is a diagram showing an embodiment of a front electrode structure of a solar cell according to the present invention. FIG. 6B is an enlarged view of the local region 2 of the solar cell structure according to the present invention of FIG. 6A. This will be described with reference to FIGS. 6A and 6B. The vertical finger electrodes 140 are arranged on both sides of the electrode assembly, and each vertical finger electrode 140 is connected to the four finger electrodes 110, and a part of the four finger electrodes 110 is connected to each other.

  To summarize the embodiments of the connecting wire electrode 130 described above, there are several types of methods for arranging the connecting wire electrode 130 as follows.

  I. The connection wire electrodes 130 are arranged on both sides of each electrode assembly 3, 4, 5 as in the embodiment of FIG. 2A. In other words, the connecting wire electrodes 130 are arranged on both sides of each electrode assembly, and are connected to the finger electrodes 110 to connect the finger electrodes to each other. That is, the connecting wire electrode 130 is connected to the end of the finger electrode 110 and connected to both ends of the adjacent finger electrodes 110 via the plurality of connecting wire electrodes 130, so that all of the finger electrodes are connected to each other. Connect.

II. The connection wire electrodes 130 are arranged on both sides of each electrode assembly 3, 4, 5 as in the embodiment of FIG. 3A. In other words, the connection wire electrode 130 is disposed on both sides of each electrode assembly and is connected to the two finger electrodes 110, and the connection wire electrode 130 can be connected to the open end of the finger electrode 110. The plurality of connection wire electrodes 130 are respectively connected to both ends of the adjacent finger electrodes 110, but the connection wire electrodes 130 are not connected to both ends of all the adjacent electrodes 110.
As shown in FIGS. 3A and 3B, only some of the adjacent finger electrodes 110 are connected by a connection wire electrode 130. In this way, the electrode shielding area can be further reduced, and at the same time, the EL measurement problem and the problem of reduced power generation efficiency due to the occurrence of disconnection of the finger electrode of the solar cell can be solved.

To summarize the above-described embodiments of the vertical finger electrodes 140, the vertical finger electrodes 140 are disposed on both sides of the electrode assemblies 3, 4, 5 as in the embodiments of FIGS. 2A, 3A, 5A and 6A. Can. In other words, the vertical finger electrodes 140 are arranged on both sides of each electrode assembly, and each vertical finger electrode 140 is connected to two finger electrodes 110, three finger electrodes 110, or four finger electrodes 110. it can.
However, the vertical finger electrode 140 of the present invention is not limited to the two finger electrodes 110, the three finger electrodes 110, or the four finger electrodes 110. If so, the present invention can also be implemented.

In addition, the vertical finger electrode 140 is disposed between the connecting wire electrode 130 and the bus bar electrode 120. For example, in order to solve the problem that the finger electrode 110 is easily disconnected near the bus bar electrode during printing, the vertical finger electrode 140 is provided. The electrode 140 is disposed close to the bus bar electrode 120, and the distance to the bus bar electrode 120 is smaller than a quarter interval between the bus bar electrode 120 and the connecting wire electrode 130.
However, the present invention is not limited to this, and those skilled in the art will be able to solve the EL measurement problem to be solved by the present invention by changing the arrangement position of the vertical finger electrodes 140 based on the pattern of printing the electrode and the electrode material. The subject of the power generation efficiency fall by disconnection generation | occurrence | production of the finger electrode of a solar cell can be achieved.

  In other embodiments, the distance from the plurality of vertical finger electrodes 140 of each electrode assembly to the connecting wire electrode 130 can be the same or different, i.e., the vertical finger electrodes 140 are along the direction of the bus bar electrode 120. It can be a linear array or an alternating array. The linear arrangement method is as shown in FIGS. 2A to 6B, and the alternating arrangement method is as shown in FIG.

In the embodiment, only one vertical finger electrode 140 is provided between the bus bar electrode 120 and the connecting wire electrode 130. In other embodiments, the vertical finger electrode 140 and the bus bar electrode 120 or the connecting wire electrode 130 One vertical finger electrode 140 may be further provided therebetween. That is, one finger electrode 110 is connected to two or more different vertical finger electrodes 140.
For example, as shown in FIG. 8, two different vertical finger electrodes 140 are provided between the finger electrodes 130, and these vertical finger electrodes 140 are also linearly arranged or alternately arranged along the direction of the bus bar electrode 120. As a result, various types of current paths can be formed, and the problem of light emission and efficiency reduction caused by disconnection of the finger electrode 110 during EL measurement can be reduced.
In some embodiments of the present invention, the solar cell according to the present invention solves the EL measurement problem, reduces the problem of power generation efficiency reduction due to the occurrence of disconnection of the finger electrode of the solar cell, and increases the power generation efficiency Have a good effect.

  In other embodiments, the widths of both ends of the finger electrode of the solar cell according to the present invention may be the same or different. For example, the width of one end near the bus bar electrode of the finger electrode is wider than the width of one end near the connecting wire electrode, or the width of one end close to the bus bar electrode of the finger electrode is different. When the width of the finger electrode is smaller than the width of one end close to the electrode and the widths of both ends of the finger electrode are different, the finger electrode is any one of triangle, trapezoid, multi-step square or concave arc line, convex arc line, straight line or diagonal line It can be set as the aspect comprised with the main line. Preferably, the finger electrode has a multi-step rectangular shape, and the width of one end close to the bus bar electrode is larger than the width of one end close to the connecting wire electrode.

DESCRIPTION OF SYMBOLS 1 Local area | region 2 Local area | region 3 Electrode assembly 4 Electrode assembly 5 Electrode assembly 100 Solar cell substrate 110 Finger electrode 111 Disconnection location 115 Finger electrode 120 Bus bar electrode 130 Connection wire electrode 131 Connection wire electrode 132 Connection wire electrode 140 Vertical finger electrode

Claims (15)

A solar cell comprising: a solar cell substrate comprising a first surface and a second surface; and a plurality of sets of electrode assemblies arranged separately from each other on the first surface of the solar cell substrate, Each of the electrode assemblies is
A bus bar electrode provided on the first surface of the solar cell substrate;
A plurality of finger electrodes arranged at intervals on both sides of the bus bar electrode;
At least one connecting wire electrode provided on the first surface of the solar cell substrate and connected to the ends of at least two finger electrodes;
Provided on the first surface of the solar cell substrate, parallel to the bus bar electrode, provided between both ends of the finger electrode, and at least for connecting to at least two adjacent finger electrodes One vertical finger electrode,
Solar cell.   2. The solar cell according to claim 1, wherein the adjacent electrode assemblies are separated from each other with a width, and the width is 30 μm to 5,000 μm.   The solar cell according to claim 1, wherein the bus bar electrodes of the electrode assembly are substantially parallel to each other.   The solar cell according to claim 1, wherein the connection wire electrode and the bus bar electrode have an intersection angle of 10 degrees to 80 degrees.   The solar cell according to claim 1, wherein the center of the bus bar electrode is at the center of the electrode assembly located.   2. The solar cell according to claim 1, wherein a line width of each of the connection wire electrodes is 10 μm to 200 μm.   2. The solar cell according to claim 1, wherein the plurality of connecting wire electrodes are connected to both ends of the finger electrode to connect all of the finger electrodes to each other.   2. The solar cell according to claim 1, wherein the plurality of connecting wire electrodes are connected to both ends of the finger electrode to connect a part of the finger electrodes to each other.   The vertical finger electrodes are disposed on both sides of each electrode assembly, and each vertical finger electrode is connected to two finger electrodes to connect two finger electrode portions to each other. The solar cell according to any one of claims 1, 7, and 8.     The vertical finger electrodes are disposed on both sides of each electrode assembly, and the vertical finger electrodes are connected to the three finger electrodes to connect the three finger electrode portions to each other. The solar cell according to any one of claims 1, 7, and 8.   The vertical finger electrodes are disposed on both sides of each electrode assembly, and the vertical finger electrodes are connected to the four finger electrodes to connect the four finger electrode portions to each other. The solar cell according to any one of claims 1, 7, and 8.   2. The solar cell according to claim 1, wherein a line width of each of the vertical finger electrodes is 10 μm to 200 μm.   The finger electrode has a first end and a second end facing each other, the first end is connected to the bus bar electrode, and a difference between the width of the first end and the width of the second end is 0 micron. The solar cell according to claim 1, wherein the solar cell is in a range of meters to 100 micrometers.   The solar cell according to claim 1, wherein the vertical finger electrode and the bus bar electrode have an intersection angle of 10 degrees to 45 degrees.   The solar cell according to claim 14, wherein the vertical finger electrode and the bus bar electrode have an intersection angle of 10 degrees to 20 degrees.

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