WO2013143475A1

WO2013143475A1 - Solar battery assembly

Info

Publication number: WO2013143475A1
Application number: PCT/CN2013/073352
Authority: WO
Inventors: Zhanfeng Jiang; Xiang Sun; Juan HU; Chunxiu Liu; Huijie FENG; Guangshuai JIA; Dongliang JING; Xiaojie JIANG; Kunyan HUANG; Mingguang WANG
Original assignee: Shenzhen Byd Auto R&D Company Limited; Byd Company Limited
Priority date: 2012-03-28
Filing date: 2013-03-28
Publication date: 2013-10-03

Abstract

A solar battery assembly is provided. The solar battery assembly comprises: a plurality of solar cells (1); and a plurality of conductive strips (5), for connecting the plurality of solar cells (1) with each other and/or for connecting a solar cell (1) of the plurality of solar cells (1) with a load, in which each solar cell (1) comprises a front electrode and a back electrode, a first end (51) of a conductive strip (5) of the plurality of conductive strips (5) for connecting two solar cells (1) is connected with the front electrode of one solar cell (1), a second end (52) of the conductive strip (5) is connected with the back electrode of the other solar cell (1), at least a portion of the first end (51) is a trapezoid in shape, and the second end (52) is uniform in width.

Description

SOLAR BATTERY ASSEMBLY

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Chinese Patent No. 201220122543.7, filed on March 28, 2012, the entire contents of which are hereby incorporated by reference.

FIELD

The present invention relates to a field of solar battery, and more particularly to a solar battery assembly.

BACKGROUND

Since a single crystal silicon solar cell is breakable and with a low power, a plurality of solar cells are connected and packaged as an assembly in practice. For example, a plurality of solar cells are connected as a cell pack, and then a plurality of cell packs are arranged in an array, in which the solar cells in a same row are connected in series and rows of solar cells are connected in parallel. For the serial connection, a back electrode of each solar cell is connected with a front electrode of an adjacent solar cell by a thin welding strip.

A conventional solar battery assembly usually uses welding strips with uniform width, the width of which is equal to or slightly larger than that of a main grid line. An internal resistance of the welding strip is depended on the width thereof under a certain thickness. During a normal working process of the solar battery assembly, a current density in the main grid lines of the front electrode of each solar cell is nonuniform, even when the welding strips with uniform width are used. Thus, it is a waste to the welding strip in a region with a small current density and also a waste to a light receiving area, which results in a relatively larger internal resistance and a relatively lower power of the solar cell.

SUMMARY

The present invention is directed to solve at least one of the problems in the prior art such as a large internal resistance and the low power of a conventional solar battery assembly.

According to a first aspect of the present invention, a solar battery assembly is provided, comprising: a plurality of solar cells; and a plurality of conductive strips, for connecting the plurality of solar cells with each other and/or for connecting a solar cell of the plurality of solar cells with a load, in which each solar cell comprises a front electrode and a back electrode, a first end of a conductive strip of the plurality of conductive strips for connecting two solar cells is connected with the front electrode of one solar cell, a second end of the conductive strip is connected with the back electrode of the other solar cell, at least a portion of the first end is a trapezoid in shape, and the second end is uniform in width. In one aspect, since a current density increases from the first end to the second end, the conductive strip is widened along a current collecting direction, so that a light shielding area is decreased at a portion with a relatively smaller width, a light receiving area is increased to certain extent, and a resistance of the solar cell is not increased; in another aspect, because the first end is for collecting the current and the second end is for delivering the collected current, the current in the second end does not change obviously so that the second end can be simply designed uniform in width.

In one embodiment, the first end is connected with the front electrode by covering a portion of the front electrode, and the second end is connected with the back electrode by covering a portion of the back electrode, that is, a connection between the conductive strip and the front electrode (or the back electrode) is realized by direct contact.

In one embodiment, a portion of the first end covering the front electrode is a trapezoid in shape, and a portion of the second end covering the back electrode is a rectangle in shape. A top-side of the trapezoid has a certain breadth, so as to facilitate a processing of the welding strips and ensure an enough strength in an initial welding.

In one embodiment, the first end is a right trapezoid in shape, and the second end is a rectangle in shape, which is easier to realize and more convenient to process in practical applications. Preferably, a length of a bottom-side of the right trapezoid is equal to a width of the rectangle so that only once processing is enough.

In one embodiment, a length of a top-side of the right trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell.

In one embodiment, a length of a top-side of the right trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the right trapezoid ranges from 1mm to 3mm.

In one embodiment, each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, 0.5mm is preferred, a length of a bottom-side of the right trapezoid ranges from 2mm to 3mm, 2.5mm is preferred, and a width of the rectangle ranges from 2mm to 3mm, 2.5mm is preferred, which can ensure the welding strength, be easy to process, lower the cost, and improve a light receiving efficiency of the of the solar battery.

In one embodiment, each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, a length of a bottom-side of the right trapezoid ranges from 2.5mm to 3mm, 0.5mm is preferred, and a width of the rectangle ranges from 2.5mm to 3mm, 2.5mm is preferred, which can ensure the welding strength, be easy to process, lower the cost, and improve a light receiving efficiency of the solar battery.

In one embodiment, the first end is an isosceles trapezoid in shape and the second end is a rectangle in shape, which may not only uniformly lead the current out, but also avoid choosing the orientation when placing the welding strip.

In one embodiment, a length of a bottom-side of the isosceles trapezoid of the first end is equal to a width of the rectangle of the second end.

In one embodiment, a length of a top-side of the isosceles trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the isosceles trapezoid ranges from 0.6% to 2% of the width of the solar cell.

In one embodiment, a length of a top-side of the isosceles trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the isosceles trapezoid ranges from 1mm to 3mm.

In one embodiment, each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid ranges from 0 to lmm, 0.5mm is preferred, a length of a bottom-side of the isosceles trapezoid ranges from 2mm to 3mm, 2.5mm is preferred, and a width of the rectangle ranges from 2mm to 3mm, 2.5mm is preferred.

In one embodiment, each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid is 0.5mm, a length of a bottom-side of the isosceles trapezoid is 2.5mm, and a width of the rectangle is 2.5mm.

In one embodiment, a length of a portion of the first end covering the front electrode ranges from 80% to 100% of that of the front electrode. The length of the portion of the first end may be equal to or less than that of the front electrode. In the later case, a certain length of the front electrode at the initial end is reserved, while a rest length is connected with the conductive strip. A length of the front electrode is designed according to that of the solar cell, for example, slightly less than that of the solar cell.

In one embodiment, a length of a portion of the second end covering the back electrode ranges from 50% to 100% of that of the back electrode. The length of the portion of the second end may be equal to or less than that of the back electrode. In the later case, a certain length of the back electrode at the initial end is reserved, while a rest length is connected with the second conductive strip. Preferably, the second connecting region may be shorter than the first connecting region. For example, the second connecting region may be 8 segmented adapting to an 8-segment back electrode, or may be a whole segment conductive strip.

In one embodiment, the conductive strip is a welding tape, and the welding strip is welded with the front electrode and/or the back electrode.

In one embodiment, the conductive strip is a conductive macromolecular tape, and the macro molecular conductive tape is adhered to the front electrode and/or the back electrode.

According to a second aspect of the present invention, a solar battery assembly is provided, comprising: a plurality of solar cells and a plurality of conductive strips, for connecting the plurality of solar cells with each other and/or for connecting a solar cell of the plurality of solar cells with a load, in which each solar cell comprises a front electrode and a back electrode, a first end of a conductive strip of the plurality of conductive strips for connecting two solar cells is connected with the front electrode of one solar cell, a second end of the conductive strip is connected with the back electrode of the other solar cell, at least a portion of the first end is a trapezoid in shape, and at least a portion of the second end's width changes with a change of a current density.

In one embodiment, the first end is connected with the front electrode by covering a portion of the front electrode, and the second end is connected with the back electrode by covering a portion of the back electrode.

In one embodiment, a portion of the first end covering the front electrode is a trapezoid in shape, and a width of a portion of the second end covering the back electrode increases with an increase of a current density, and decreases with a decrease of the current density.

In one embodiment, the first end is a right trapezoid in shape, and the second end is a triangle or a trapezoid in shape. Preferably, an edge of the second end is a vertex of the triangle or the top-side of the trapezoid. With such structure, it can not only ensure an excellent properties, but also be easier to realize and more convenient to process in practical applications.

In one embodiment, a length of a bottom-side of the right trapezoid of the first end is equal to a length of a bottom-side of the triangle or the trapezoid of the second end.

In one embodiment, a length of a top-side of the right trapezoid ranges from 0% to 1.3% of the width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell.

In one embodiment, each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, 0.5mm is preferred, a length of a bottom-side of the right trapezoid ranges from 2mm to 3mm, 2.5mm is preferred.

In one embodiment, each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, 0.5mm is preferred, a length of a bottom-side of the right trapezoid ranges from 2.5mm to 3mm, 2.5mm is preferred.

In one embodiment, the first end is an isosceles trapezoid in shape, and the second end is a triangle or a trapezoid in shape, which may not only uniformly lead the current out, but also avoid choosing the orientation when placing the welding strip.

In one embodiment, a length of a bottom-side of the isosceles trapezoid is equal to a length of a bottom-side of the triangle or the trapezoid.

In one embodiment, each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid ranges from 0 to lmm, 0.5mm is preferred, a length of a bottom-side of the isosceles trapezoid ranges from 2mm to 3mm, 2.5mm is preferred.

In one embodiment, each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid is 0.5mm, 0.5mm is preferred, a length of a bottom-side of the isosceles trapezoid is 2.5mm, 2.5mm is preferred.

In one embodiment, the conductive strip is a conductive macro molecular tape, and the macro molecular conductive tape is adhered to the front electrode and/or the back electrode.

According to a third aspect of the present invention, a solar battery assembly is provided, comprising: one solar cell, and two conductive strips for connecting the one solar cell with a load, in which the one solar cell comprises a front electrode and a back electrode, a first end of one conductive strip is connected with the front electrode, a second end of the other conductive strip is connected with the back electrode, both a second end of the one conductive strip and a first end of the other conductive strip are connected with the load, at least a portion of the first end is a trapezoid in shape, and the second end is uniform in width.

According to a fourth aspect of the present invention, a solar battery assembly is provided, comprising: one solar cell, and two conductive strips for connecting the one solar cell with a load, in which the one solar cell comprises a front electrode and a back electrode, a first end of one conductive strip is connected with the front electrode, a second end of the other conductive strip is connected with the back electrode, both a second end of the one conductive strip and a first end of the other conductive strip are connected with the load, at least a portion of the first end is a trapezoid in shape, and at least a portion of the second end's width changes with a change of a current density.

With the solar battery assembly according to embodiment of the present invention, according to a current density distribution of the main grid line in a front face (i.e., a light receiving face), a wider conductive strip is used where the current density is large to reduce the internal resistance and a power loss, and a narrower conductive strip is used where the current density is small to increase the light receiving area and an actual power. By using the conductive strip with width varying with the current density distribution, an output power of the solar battery assembly is increased. Moreover, the solar battery assembly is easy to realize.

DESCRIPTION OF THE DRAWINGS

Fig. 1 is a schematic structural view of a front face (i.e., a light receiving face) of a solar cell according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of a back face (i.e., a light shading face) of the solar cell according to an embodiment of the present invention;

Fig. 3 is a schematic structural view of a conductive strip according to embodiment 1 of the present invention;

Fig. 4 is a schematic structural view of the front face of one solar cell connected with a conductive strip according to embodiment 1 of the present invention;

Fig. 5 is a schematic structural view of the back face of one solar cell connected with a conductive strip according to embodiment 1 of the present invention;

Fig. 6 is a schematic structural view of two adjacent solar cells according to embodiment 1 of the present invention;

Fig. 7 is a schematic structural view of a conductive strip according to embodiment 2 of the present invention;

Fig. 8 is a schematic structural view of the front face of one solar cell connected with a conductive strip according to embodiment 2 of the present invention;

Fig. 9 is a schematic structural view of a conductive strip according to embodiment 3 of the present invention;

Fig. 10 is a schematic structural view of the back face of one solar cell connected with a conductive strip according to embodiment 3 of the present invention;

Fig. 11 is a schematic structural view of a conductive strip according to embodiment 4 of the present invention;

Fig. 12 is a schematic structural view of the back face of one solar cell connected with a conductive strip according to embodiment 4 of the present invention;

Fig. 13 is a schematic structural view of the back face of one solar cell connected with a conductive strip according to embodiment 4 of the present invention; and

Fig. 14 is a schematic structural view of a conductive strip according to comparing embodiment 1.

DETAILED DESCRIPTION

The aforementioned features and advantages of the present invention as well as the additional features and advantages thereof will be further clearly understood hereafter as a result of a detailed description of the following embodiments when taken in conjunction with the drawings.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the specification, including definitions, will control.

The present invention relates to a solar battery assembly.

EMBODIMENT 1 A front electrode refers to the current (commonly a negative electrode) on a light receiving face (i.e., a front face hereinafter) for leading a current out. As shown in Fig. 1, the front electrode is commonly achieved by several main grid lines 2 printed on the front face of the solar cell 1 (for example, two or three main grid lines). The main grid lines 2 are commonly made by coating and baking a silver conductive paste. The current is collected by a plurality of thin auxiliary grid lines 3 which are connected to the main grid lines 2, and then led out by the main grid lines 2.

The back electrode refers to an electrode (commonly a positive electrode) on a face coating a back electric field (i.e., a back face hereinafter) for leading a current out. As shown in Fig. 2, the back electrode is commonly achieved by several grid lines 4 printed on the back face of the solar cell 1. The grid lines 4 commonly coincide with the main grid lines 2 respectively. The grid lines 4 are commonly made by coating and baking the silver conductive paste. Each grid line 4 may be whole segmented or segmented.

In one embodiment, there is one solar cell 1, and the main grid lines 2 and the grid lines 4 are connected with one conductive strip 5 respectively. The current on the solar cell 1 is led out by the conductive strips 5, and then connected with a junction box or likewise to electrically connect with a load. In another embodiment, there are at least two solar cells 1, and two adjacent solar cells are connected with each other by the conductive strip 5, that is, the front electrode of one solar cell 1 and the back electrode of the other solar cell 1 are connected by one conductive strip 5. A solar cell 1 arranged at an outside is connected with a junction box or likewise to electrically connect with a load.

The conductive strip 5 may be any conventional conductive strip, for example, a metal strip (i.e. a welding strip), which can be a copper strip. The conductive strip 5 may be welded with the front electrode and/or the back electrode such as by tin soldering. Alternatively, the conductive strip 5 may be welded with the front electrode and/or the back electrode by conductive adhesive tape, particularly a macro molecular conductive tape which may be directly stuck on a surface of the main grid line 2 or the grid line 4.

A first end 51 of the conductive strip 5 for connecting two solar cells 1 is connected with the front electrode of one solar cell. Commonly, the conductive strip 5 totally or partially covers on the main grid line 2 without shading a light receiving area of the solar cell. An overlay region is the first end 51. The current can be uniformly led out by such design.

When a current of the front electrode of the solar cell 1 is led out by the conductive strip 5, the current in the grid line 2 is nonuniform, and thus a current density of the conductive strip 5 is different. In this embodiment, at least a portion of the first connecting region's width changes with a change of a current density so as to lead the current out better and improve a light-receiving efficiency and a photoelectric conversion efficiency of the solar battery. Specifically, a width of the first end 51 increases with an increase of the current density, and decreases with a decrease of the current density. A wider conductive strip is used where the current density is large to reduce the internal resistance and a power loss, and a narrower conductive strip is used where the current density is small to increase the light receiving area and an actual power.

As shown in Figs. 3 and 4, in this embodiment, the first end 51 is a right trapezoid in shape. Commonly, the current density increases gradually along a direction of the current with an accumulation of electrons, thus, a width of the first end 51 gradually increases along the direction of the current.

Commonly, sizes of the conductive strips 5 and the first end 51 are designed according to the sizes of the solar cell 1 and the main grid line 2. Preferably, a length of a top-side of the right trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell. For a normal solar cell, a length of a top-side of the right trapezoid may range from 0 to 2mm, and a length of a bottom-side of the right trapezoid may range from 1mm to 3mm. A length of a portion of the first end 51 covering the front electrode ranges from 80% to 100% of that of the front electrode. The length of the portion of the first end 51 may be equal to or less than that of the front electrode. In the later case, a certain length of the front electrode at the initial end is reserved, while a rest length is connected with the conductive strip 5. In one embodiment, the length of the solar cell is 156mm; the length of the main grid line 2 is 153mm; the length of the first end 51 is 153mm, that is, the main grid line 2 is printed at 1.5mm away from an edge of the solar cell, and the conductive strip 5 is welded from an initial end of the main grid line 2, that is, the total length of the main grid line 2 is covered with the conductive strip 5.

Taking a solar cell with size of 156ηιηι^χ 156ιηιη^χ200μιη for example, each front electrode has three main grid lines 2. Each main grid line 2 is 1.5mm in width and 153mm in length. Each main grid line 2 is covered by one conductive strip 5 with a shape of right trapezoid. A top-side of the right trapezoid is 0.5mm in length, a bottom-side of the right trapezoid is 2.5mm, and a height of the right trapezoid (i.e., the first end) is 153mm.

A second end 52 of the conductive strip 5 for connecting two solar cells 1 is connected with the back electrode of one solar cell. Commonly, the conductive strip 5 totally or partially covers on the grid line 4 without shading a light receiving area of the solar cell. An overlay region is the second end 52. The current can be uniformly led out by such design.

The shape of the second end 52 may be any conventional shape known in the art. In one embodiment, a width of the second end 52 is uniform. Particularly, the second end 52 is a rectangle in shape as shown in Fig. 5. Taking a solar cell with size of 156Γηιη^χ 156ιηιη^χ200μιη for example, the grid line 4 is 1.8mm in width and 136mm in length. The grid line 4 is printed from the edge of the solar cell 1 and may be 8 segmented. The second end 52 may be 2.5mm in width and 136mm in length. The conductive strip 5 is welded from the initial end of the grid line 4, that is, the total length of the grid line 4 is covered with the conductive strip 5. The second end 52 may be designed as a whole conductive strip.

According to some embodiments of the present invention, the conductive strip with this shape can be formed by cutting a conventional conductive strip. For example, a bevel edge of one end of the conductive strip may be cut to form the first end 51. It is convenient to process and easy to implement.

A plurality of solar cells are connected in serials. Fig. 4 is a schematic structural view of the front face of one solar cell, and Fig. 5 is a schematic structural view of the back face of an adjacent solar cell. As shown in Fig. 4, there are three main grid lines 2 as the front electrodes, i.e. the negative electrodes. Each main grid line 2 is welded with one conductive strip 5. A triangular part of the conductive strip 5 covers the main grid line 2. A vertex of the triangle falls on a median line of the main grid lines 2 and is 1.5mm away from the edge of the solar cell. As shown in Fig. 5, there are three grid lines 4 as the back electrodes, i.e. the positive electrodes. Each grid line 4 is welded with one conductive strip 5. A rectangular part of the conductive strip 5 covers the grid line 4 and stops at 10mm away from the edge of the solar cell.

As shown in Fig. 6, two solar cells 11 and 12 connected in series are taken as an example. Firstly, the right trapziform part of each welding strip is welded onto the front electrode. Then, the other half (i.e., the rectangular part) of each welding strip is welded onto the back electrode of an adjacent solar cell, and thus a plurality of solar cells in one row are connected in series to form a cell pack. Then a plurality of cell packs are connected in series to form a battery array. Alternatively, one end of the right trapziform part of each welding strip is welded onto the front electrode of each solar cell, and then, each solar cell with the welding strip is over turned and the other half of each welding strip is welded onto the back electrode of an adjacent solar cell. It should be noted that, depending on a requirement, it is also possible to connect the solar packs in parallel to adapt to a desired output current and output voltage. Finally, two welding strips will be remained and output as the positive electrode and negative electrode of the battery array. Subsequent processing steps known to those skilled in the art will be briefly described as follows. For example, a glass plate is provided on an operation stage; a first binding agent layer is formed on the glass plate; the battery array is arranged on the binding agent layer; a second binding agent layer is formed on the battery array; a backing plate is formed on the second binding agent layer; the above layers are laminated in an laminating machine to form the solar battery assembly. Then the solar battery assembly is installed with borders, and the positive electrode and the negative electrode are connected to the junction box to form an ultimate solar battery assembly. EMBODIMENT 2

As shown in Fig. 7, the first end 51 with the shape of isosceles trapezoid is described in details in this embodiment. Commonly, sizes of the conductive strip 5 and the first end 51 (i.e., the isosceles trapezoid) are designed according to sizes of the solar cell and the main grid line 2. Preferably, a length of a top-side of the right trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell. For a normal solar cell, a length of a top-side of the right trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the right trapezoid ranges from 1mm to 3mm. Taking a solar cell with size of 156ηΐΉ>< 156ηιιη><200μιη as example, each front electrode has three main grid lines 2, and each main grid line 2 is 1.5mm in width and 15mm in length. A top-side of the isosceles trapezoid is 0.5mm in length, a bottom-side of the isosceles trapezoid is 2.5mm, and a height of the isosceles trapezoid (i.e., the first end) is 153mm. An initial end of the first end begins from the start end of the main grid line 2. In this embodiment, the second end 52 is a rectangle in shape. The grid line 4 is 1.8mm in width, 136mm in length and 8 segmented. The second end 52 is 2.5mm in width and 136mm in length.

A plurality of solar cells are connected in series. Fig. 8 is a schematic structural view of the front face of one solar cell. As shown in Fig. 8, there are three main grid lines 2 as the front electrodes, i.e. the negative electrodes. Each main grid line 2 is welded with one conductive strip 5 shown in Fig. 7. A isosceles triangular part of the conductive strip 5 covers the main grid line 2. A vertex of the isosceles triangle falls on a center position of the main grid lines 2 and 1.5mm away from the edge of the solar cell. There are three grid lines 4 as the back electrodes, i.e. the positive electrodes. Each grid line 4 is welded with one conductive strip 5 shown in the Fig. 7. A rectangular second end 52 of the conductive strip 5 covers the grid line 4 and stops at 10mm away from the edge of the solar cell. The battery assembly is formed by the method substantially similar to EMBODIMENT 1.

EMBODIMENT 3

When a current of the back electrode of the solar cell 1 is led out by the conductive strip 5, the current in the grid line 4 is also nonuniform, thus a current density of the conductive strip 5 is slightly different. In this embodiment, at least a portion of the second end's width changes with a change of a current density so as to lead the current out better and lower a cost. Specifically, a width of the second end 52 increases with an increase of the current density, and decreases with a decrease of the current density. A wider conductive strip is used where the current density is large to reduce the internal resistance and a power loss, and a narrower conductive strip is used where the current density is small to lower the cost.

As shown in Fig. 11, the conductive strip 5 comprises the second end 52 connected to the back electrode of the solar cell. The second end 52 has an initial end and a distal end. The distal end extends to the load or the back electrode. The second end 52 gradually becomes narrower from the initial end to the distal end, that is, the second end 52 gradually becomes wider from the distal end to the initial end. Commonly, the current density increases gradually along a direction of the current with an aggregation of electrons, thus, preferably, the second end 52 gradually decreases in width from the initial end to the distal end.

Commonly, sizes of the conductive strips 5 and the second end 52 are designed according to sizes of the solar cell 1 and the grid line 4. Preferably, a width of a widest portion of the second end 52 ranges from 0% to 1.3% of that of the solar cell 1, while a width of a narrowest portion of the second end 52 ranges from 0.6% to 2% of that of the solar cell 1. For example, for a common solar cell, the width of the widest portion of the second end 52 may be 2.5mm, and a width of a narrowest portion of the second end 52 may be 0.5mm (the narrowest portion even may be a point). A length of the second end 52 ranges from 50% to 100% of that of the back electrode. The length of the second end 52 may be equal to that of the back electrode, that is, the length of the second end 52 may be equal to that of the solar cell. Alternately, the length of the second end 52 may be less than that of the back electrode, that is, a certain length of the second electrode at the initial end is reserved, while a rest length is connected with the conductive strip 5 to avoid edge short circuit. The second connecting region 52 may be 8 segmented or a whole conductive strip.

Preferably, the second end 52 is symmetric about a longitudinal midline, that is, a current is uniformly led out from both sides of the midline. Usually the second end 52 is symmetric about a longitudinal midline of the grid line 4 to ensure a uniform current density and decrease the internal resistance. The shape of the second end 52 may be a triangle, such as an isosceles triangle or a right triangle, or may be a trapezoid. Preferably, a length of a bottom-side of the triangle or the trapezoid of the second end is equal to that of a bottom-side of the isosceles trapezoid of the first end, which is not only ensure a uniform current, but also easy to realize and convenient to process in practical applications.

As shown in Fig. 9, the first end 51 with the shape of isosceles trapezoid is described in details in this embodiment. Taking a solar cell with size of 156ηΐΉ>< 156ηιιη><200μιη as example, the main grid line 2 is 1.5mm in width and 153mm in length. The widest portion of the isosceles trapeziform first end 51 is a bottom-side of the isosceles trapezoid, which is 2.5mm in length; and the narrowest portion of the isosceles trapeziform first end 51 is a top-side of the isosceles trapezoid, which is 0.5mm in length. Such design may facilitate the welding. The length of the first end 51 is a height of the isosceles trapezoid, which is 153mm. The initial end of the first end 51 begins from the start end of the main grid line 2. In this embodiment, the second end 52 is a right triangle in shape. The grid line 4 is 1.8mm in width, 136mm in length and 8 segmented. The widest portion of the right triangle second end 52 is a bottom-side of the right triangle, which is 2.5mm in length. The length of the portion of the second end 52 covering the grid line 4 is a height of the right triangle, which is 136mm.

A plurality of solar cells are connected in series. Fig. 10 is a schematic structural view of the front face of one solar cell. As shown in Fig. 10, there are three main grid lines 2 as the front electrodes, i.e. the negative electrodes. Each main grid line 2 is welded with one conductive strip 5 shown in the Fig. 9. An isosceles trapezoid part of the conductive strip 5 covers the main grid line 2. The top-side of the isosceles trapezoid falls on a center position of the main grid lines 2 and 1.5mm away from the edge of the solar cell. There are three grid lines 4 as the back electrodes, i.e. the positive electrodes. Each grid line 4 is welded with one conductive strip 5 shown in the Fig. 9. A right triangular part of the second end 52 covers the grid line 4 and stops at 10mm away from the edge of the solar cell. The battery assembly is formed by the method substantially similar to EMBODIMENT 1.

EMBODIMENT 4

The first end 51 is a right trapezoid in shape, and the second end 52 is a right trapezoid in shape as shown in Fig. 11, 12 and 13. Taking a solar cell with size of 156mmx 156ιηιη^χ200μιη for example, the grid line 2 is 1.5mm in width, and 153mm in length. A bottom-side of the right trapeziform first end 51 is 2.5mm, a top-side of the right trapeziform first end 51 is 0.5mm, and the length of the first end 51 is a height of the isosceles trapezoid, which is 153mm. The conductive strip 5 begins from a start end of the main grid line 2.

There are three grid lines 4 as the back electrodes on the back surface of the solar cell, i.e. the positive electrodes. The grid line 4 is 1.8mm in width, and 136mm in length, and 8 segmented. A bottom-side of the right trapeziform second end 52 is 2.5mm, a top-side of the right trapeziform second end 52 is 0.5mm, and the length of the second end 52 is a height of the isosceles trapezoid, which is 136mm. The second end 52 covers the main grid line 4 and stops at 10mm away from the edge of the solar cell. The battery assembly is formed by the method substantially similar to EMBODIMENT 1.

COMPARING EMBODIMENT 1

A conventional conductive strip 5 with a rectangular first connecting region 51 and a rectangular second connecting region 52 as shown in Fig. 14 is taken as example for forming the solar battery assembly. The size and number of the solar cells 1, the method for forming the solar battery assembly, a total length and a welding position of the conductive strip 5 are same with EMBODIMENT 1. The rectangle is 1.5mm in width and 300mm in length.

COMPARING EMBODIMENT 2

A conventional conductive strip 5 with a rectangular first connecting region 51 and a rectangular second connecting region 52 as shown in Fig. 14 is taken as example for forming the solar battery assembly. The size and number of the solar cells 1, the method for forming the solar battery assembly, a total length and a welding position of the conductive strip 5 are same with EMBODIMENT 1. The rectangle is 2.5mm in width and 300mm in length.

Performance Test

The solar battery assemblies according to EMBODIMENTS 1-4 and COMPARING EMBODIMENTS 1-2 are tested at a same ambient temperature respectively, by using a solar battery assembly test apparatus with simulated AMI .5 sunlight, the spectra of which is in accordance with IEC 60904-9, Level A. A standard solar battery assembly with a same size and a same spectral response is used to calibrate each above solar battery assembly before testing. Results are list in Table 1.

Table 1

It can be seen from the results that, with the solar battery assembly according to embodiment of the present invention, the internal resistance and the power loss are obviously reduced, and the output power is significantly increased. Meanwhile, the photoelectric conversion efficiency of the solar battery is improved due to an increase of the light-receiving efficiency. Furthermore, by applying the solar battery assembly in a solar power station, the total output power of the solar power station will be significantly increased. Moreover, the solar battery assembly is at low cost and easy to realize.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications all falling into the scope of the claims and their equivalents may be made in the embodiments without departing from spirit and principles of the disclosure.

Claims

WHAT IS CLAIMED IS:

1. A solar battery assembly, comprising:

a plurality of solar cells; and

a plurality of conductive strips, for connecting the plurality of solar cells with each other and/or for connecting a solar cell of the plurality of solar cells with a load, wherein each solar cell comprises a front electrode and a back electrode, a first end of a conductive strip of the plurality of conductive strips for connecting two solar cells is connected with the front electrode of one solar cell, a second end of the conductive strip is connected with the back electrode of the other solar cell, at least a portion of the first end is a trapezoid in shape, and the second end is uniform in width.

2. The solar battery assembly of claim 1, wherein the first end is connected with the front electrode by covering a portion of the front electrode, and the second end is connected with the back electrode by covering a portion of the back electrode.

3. The solar battery assembly of claim 2, wherein a portion of the first end covering the front electrode is a trapezoid in shape, and a portion of the second end covering the back electrode is a rectangle in shape.

4. The solar battery assembly of any of claims 1-3, wherein the first end is a right trapezoid in shape, and the second end is a rectangle in shape.

5. The solar battery assembly of claim 4, wherein a length of a bottom-side of the right trapezoid is equal to a width of the rectangle.

6. The solar battery assembly of claim 4, wherein a length of a top-side of the right trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell.

7. The solar battery assembly of claim 4, wherein a length of a top-side of the right trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the right trapezoid ranges from 1mm to 3mm.

8. The solar battery assembly of claim 4, wherein each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, a length of a bottom-side of the right trapezoid ranges from 2mm to 3mm, and a width of the rectangle ranges from 2mm to 3mm.

9. The solar battery assembly as recited in claim 4, wherein each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the right trapezoid ranges from 0 to lmm, a length of a bottom-side of the right trapezoid ranges from 2.5mm to 3mm, and a width of the rectangle ranges from 2.5mm to 3mm.

10. The solar battery assembly of any of claims 1-3, wherein the first end is an isosceles trapezoid in shape and the second end is a rectangle in shape.

11. The solar battery assembly of claim 10, wherein a length of a bottom-side of the isosceles trapezoid is equal to a width of the rectangle.

12. The solar battery assembly of claim 10, wherein a length of a top-side of the isosceles trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the isosceles trapezoid ranges from 0.6% to 2% of the width of the solar cell.

13. The solar battery assembly of claim 10, wherein a length of a top-side of the isosceles trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the isosceles trapezoid ranges from lmm to 3mm.

14. The solar battery assembly of claim 10, wherein each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid ranges from 0 to lmm, a length of a bottom-side of the isosceles trapezoid ranges from 2mm to 3mm, and a width of the rectangle ranges from 2mm to 3mm.

15. The solar battery assembly of claim 10, wherein each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid is 0.5mm, a length of a bottom-side of the isosceles trapezoid is 2.5mm, and a width of the rectangle is 2.5mm.

16. The solar battery assembly of any of claims 1-15, wherein

a length of a portion of the first end covering the front electrode ranges from 80% to 100% of that of the front electrode; and

a length of a portion of the second end covering the back electrode ranges from 50% to 100% of that of the back electrode.

17. The solar battery assembly of any of claims 1-16, wherein the conductive strip is a welding tape, and the welding strip is welded with the front electrode and/or the back electrode.

18. The solar battery assembly of any of claims 1-16, wherein the conductive strip is a conductive macro molecular tape, and the macromolecular conductive tape is adhered to the front electrode and/or the back electrode.

19. A solar battery assembly, comprising:

a plurality of solar cells; and

a plurality of conductive strips, for connecting the plurality of solar cells with each other and/or for connecting a solar cell of the plurality of solar cells with a load, wherein each solar cell comprises a front electrode and a back electrode, a first end of a conductive strip of the plurality of conductive strips for connecting two solar cells is connected with the front electrode of one solar cell, a second end of the conductive strip is connected with the back electrode of the other solar cell, at least a portion of the first end is a trapezoid in shape, and at least a portion of the second end's width changes with a change of a current density.

20. The solar battery assembly of claim 19, wherein the first end is connected with the front electrode by covering a portion of the front electrode and the second end is connected with the back electrode by covering a portion of the back electrode.

21. The solar battery assembly of claim 20, wherein a portion of the first end covering the front electrode is a trapezoid in shape, and a width of a portion of the second end covering the back electrode increases with an increase of a current density, and decreases with a decrease of the current density.

22. The solar battery assembly of any of claims 19-21, wherein the first end is a right trapezoid in shape, and the second end is a triangle or a trapezoid in shape.

23. The solar battery assembly of claim 22, wherein a length of a bottom-side of the right trapezoid is equal to a length of a bottom-side of the triangle or the trapezoid.

24. The solar battery assembly of claim 22, wherein a length of a top-side of the right trapezoid ranges from 0% to 1.3% of the width of the solar cell, and a length of a bottom-side of the right trapezoid ranges from 0.6% to 2% of the width of the solar cell.

25. The solar battery assembly of claim 22, wherein a length of a top-side of the right trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the right trapezoid ranges from 1mm to 3mm.

26. The solar battery assembly of claim 22, wherein each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, a length of a bottom-side of the right trapezoid ranges from 2mm to 3mm.

27. The solar battery assembly of claim 22, wherein each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the right trapezoid ranges from 0 to 1mm, a length of a bottom-side of the right trapezoid ranges from 2.5mm to 3mm.

28. The solar battery assembly of any of claims 19-21, wherein the first end is an isosceles trapezoid in shape, and the second end is a triangle or a trapezoid in shape.

29. The solar battery assembly of claim 28, wherein a length of a bottom-side of the isosceles trapezoid is equal to a length of a bottom-side of the triangle or the trapezoid.

30. The solar battery assembly of claim 28, wherein a length of a top-side of the isosceles trapezoid ranges from 0% to 1.3% of a width of the solar cell, and a length of a bottom-side of the isosceles trapezoid ranges from 0.6% to 2% of the width of the solar cell.

31. The solar battery assembly of claim 28, wherein a length of a top-side of the isosceles trapezoid ranges from 0 to 2mm, and a length of a bottom-side of the isosceles trapezoid ranges from 1mm to 3mm.

32. The solar battery assembly of claim 28, wherein each solar cell comprises three front electrodes and three back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid ranges from 0 to 1mm, a length of a bottom-side of the isosceles trapezoid ranges from 2mm to 3mm.

33. The solar battery assembly of claim 28, wherein each solar cell comprises two front electrodes and two back electrodes, each front electrode is connected with one conductive strip, each back electrode is connected with another one conductive strip, a length of a top-side of the isosceles trapezoid is 0.5mm, a length of a bottom-side of the isosceles trapezoid is 2.5mm.

34. The solar battery assembly of any of claims 19-33, wherein

a length of a portion of the first end covering the front electrode ranges from 80% to 100% of that of the front electrode; and a length of a portion of the second end covering the back electrode ranges from 50% to 100% of that of the back electrode.

35. The solar battery assembly of any of claims 19-34, wherein the conductive strip is a welding strip, and the welding strip is welded with the front electrode and/or the back electrode.

36. The solar battery assembly of any of claims 19-34, wherein the conductive strip is a conductive macromolecular tape, and the macromolecular conductive tape is adhered to the front electrode and/or the back electrode.