Patent ID: 12199203

The accompanying drawings herein, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain principles of the present disclosure.

DESCRIPTION OF EMBODIMENTS

In order to better understand the technical solutions of the present disclosure, the following is a detailed description of embodiments of the present disclosure with reference to the accompanying drawings.

It should be made clear that the embodiments described are only part of rather than all of the embodiments of the present disclosure. All other embodiments acquired by those of ordinary skill in the art without creative efforts based on the embodiments of the present disclosure shall fall within the protection scope of the present disclosure.

The terms used in the specification of the present disclosure are intended only to describe particular embodiments and are not intended to limit the present disclosure. As used in the embodiments of the present disclosure and the appended claims, the singular forms of “a/an”, “the”, and “said” are intended to include plural forms, unless otherwise clearly specified by the context.

It is to be understood that the term “and/or” used herein is merely an association relationship describing associated objects, indicating that three relationships may exist. For example, A and/or B indicates that there are three cases of A alone, A and B together, and B alone. In addition, the character “/” herein generally means that associated objects before and after “/” are in an “or” relationship.

It is to be noted that orientation words such as “above”, “below”, “left” and “right” described in the embodiments of the present disclosure are described from perspectives as shown in the accompanying drawings and should not be understood as limitations on the embodiments of the present disclosure. In addition, in the context, it is to be further understood that, when one element is connected “above” or “below” another element, it can not only be directly connected “above” or “below” the other element, but also be indirectly connected “above” or “below” the other element through an intermediate element.

A solar cell is a semiconductor device that converts solar energy into electric energy. Low manufacturing costs and high energy conversion efficiency have always been the goal of the solar cell industry. For an IBC solar cell, all electrodes are disposed on a backlight surface of the solar cell, and no electrode shields a light incident surface of the IBC solar cell, thereby effectively increasing a short-circuit current of the solar cell and improving energy conversion efficiency of the solar cell. An existing IBC solar cell generally includes a semiconductor substrate and a metallized electrode structure arranged on the semiconductor substrate. The metallized electrode structure includes finger electrodes and a busbar. When the IBC solar cell is in operation, currents are first collected to the nearest finger, and then collected through the finger to the busbar connected thereto and a conductive line (e.g., an external solder strip) connected to the busbar, and then the currents are drawn out. The busbar in the metallized electrode structure is generally made of relatively expensive silver paste, which has high costs, a large width and thus a large usage amount. The busbar covers the solar cell and shields a lot of light receiving areas, which may reduce photoelectric conversion efficiency of the solar cell.

With respect to the problems of high manufacturing costs, a large usage amount of metallized paste and reduction of photoelectric conversion efficiency of the solar cell due to presence of a busbar in the metallized electrode structure of the existing IBC solar cell, the applicant has found according to studies that the IBC solar cell requires a wider finger and can achieve high efficiency even under the design of a relatively large line width. Moreover, the design of wide electrode lines enables an effect of firm soldering with the conductive line, thereby achieving the purpose of replacing the busbar by the conductive line.

In consideration of the above, according to some embodiments of the present disclosure, a busbar-free IBC solar cell is proposed. The IBC solar cell may be a P-type IBC solar cell or an N-type IBC solar cell. As shown inFIG.1, the IBC solar cell includes a semiconductor substrate1, a plurality of finger electrode lines2and a plurality of conductive lines3. In some embodiments, the semiconductor substrate1is a semiconductor silicon wafer. The semiconductor silicon wafer may be made of, for example, monocrystalline silicon, polycrystalline silicon or microcrystalline silicon. The finger electrode line2may be made of a metal material with good electrical conductivity. In some embodiments, the finger electrode line2is made of silver or aluminum paste, and the finger electrode line2may have a width ranging from 10 μm to 150 μm. The conductive line3has good electrical conductivity. In some embodiments, the conductive line3is a tinned copper conductive line. The finger electrode line2can collect and direct currents generated by a photovoltaic effect to the conductive line3. The conductive line3then draws out the collected currents. The finger electrode line2and the conductive line3form a power hub of the IBC solar cell. For the IBC solar cell, the finger electrode line2and the conductive line3are designed on a back surface of the semiconductor substrate1.

As shown inFIG.1, the finger electrode line2includes a first finger electrode line21and a second finger electrode line22. Among the first finger electrode line21and the second finger electrode line22, one is a finger negative electrode line, and the other is a finger positive electrode line. The first finger electrode line21and the second finger electrode line22are alternately arranged on the semiconductor substrate1. The first finger electrode line21and the second finger electrode line22form local or full ohmic contact with the semiconductor substrate1, respectively. In some embodiments, when the first finger electrode line21and the second finger electrode line22form full ohmic contact with the semiconductor substrate1, firing-through paste is placed at positions of the first finger electrode line21and the second finger electrode line22by a screen printing process, an inkjet printing process or a laser transfer process. Alternatively, the first finger electrode line21and the second finger electrode line22are formed by electroplating after opening or a physical vapor deposition (PVD) method. In some embodiments, when the first finger electrode line21and the second finger electrode line22form local ohmic contact with the semiconductor substrate1, non-firing-through paste is placed at positions of the first finger electrode line21and the second finger electrode line22by a screen printing process, an inkjet printing process or a laser transfer process, or a metal layer is deposited by the PVD method.

The conductive line3includes a first conductive line31and a second conductive line32that are alternately arranged. The first conductive line31is connected to the first finger electrode line21, and the first conductive line31is spaced apart from the second finger electrode line22, to prevent short circuit caused by contact of the first conductive line31with the second finger electrode line22. The second conductive line32is connected to the second finger electrode line22, and the second conductive line32is spaced apart from the first finger electrode line21, to prevent short circuit caused by contact of the second conductive line32with the first finger electrode line21.

In an embodiment, the first conductive line31is vertically connected to the first finger electrode line21, and the second conductive line32is vertically connected to the second finger electrode line22.

The IBC solar cell according to some embodiments does not include any busbar, the conductive lines3instead of the busbars are directly connected to the finger electrode lines on the solar cell. High photoelectric conversion efficiency may also be achieved under the design of a relatively large line width when the IBC solar cell requires wider finger electrode lines. In addition, the design of wide finger electrode lines in the IBC solar cell enables a firm soldering between the finger electrode lines and the conductive lines3.

According to some embodiments of the present disclosure, as shown inFIG.1andFIG.2, the first finger electrode line21is formed by a plurality of first finger electrode sub-lines211arranged at intervals, and the second finger electrode line22is formed by a plurality of second finger electrode sub-lines221arranged at intervals. In such a configuration, the first finger electrode line21and the second finger electrode line22form a segmented electrode line structure, which reduces a usage amount of paste and improves efficiency of the solar cell. A first interval2110is provided between two adjacent ones of the plurality of first finger electrode sub-lines211. A second interval2210is provided between two adjacent ones of the plurality of second finger electrode sub-lines221, and the first conductive line31passes through the second interval2210. The first interval2110of the first finger electrode line21and the second interval2210of the second finger electrode line22adjacent to each other are mutually staggered, and the second conductive line32passes through the first interval2110.

The first finger electrode line21and the second finger electrode line22according to some embodiments adopt a segmented electrode line structure, which can effectively reduce a usage amount of paste. With characteristics of the segmented electrode line structure, during maintenance of an effective connection between the first conductive line31and the first finger electrode line21with a same polarity, the first conductive line31passes through the second interval2210so that the first conductive line31is spaced apart from the second finger electrode line22with an opposite polarity. During maintenance of an effective connection between the second conductive line32and the second finger electrode line22with a same polarity, the second conductive line32passes through the first interval2110so that the second conductive line32is spaced apart from the first finger electrode line21with an opposite polarity. Such a configuration effectively prevents short circuit caused by the connection between the conductive line3and the finger electrode line2with opposite polarities.

According to some embodiments of the present disclosure, a width c1 of the first interval2110and a width c2 of the second interval2210range from 100 μm to 1000 μm. The width c1 of the first interval2110and the width c2 of the second interval2210may be, for example, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm or 1000 μm, and may also be other values in the above range, which is not limited herein.

With the further limitations on the width c1 of the first interval2110and the width c2 of the second interval2210, a transverse distance between the conductive line3and the finger electrode line2becomes larger without affecting current collection of the finger electrode line2, and the risk of short circuit is greatly reduced.

According to some embodiments of the present disclosure, as shown inFIG.1andFIG.2, the first conductive line31passes through a middle position of the second interval2210. The second conductive line32passes through a middle position of the first interval2110. That is, the first conductive line31is at a same distance from the second finger electrode sub-lines221on two sides, which is half the width c1 of the first interval2110. In some embodiments, the distances between the first conductive line31and the second finger electrode sub-lines221on two sides range from 50 μm to 500 μm. The second conductive line32is at a same distance from the first finger electrode sub-lines211on two sides, which is half the width c2 of the second interval2210. In some embodiments, the distances between the second conductive line32and the first finger electrode sub-lines211on two sides range from 50 μm to 500 μm.

The first conductive line31passes through a middle position of the second interval2210and the second conductive line32passes through a middle position of the first interval2110, so that the first conductive line31and the second conductive line32, when offset to two sides by the same amplitude, may not contact the second finger electrode sub-line221and the first finger electrode sub-line211to cause short circuit of the solar cell.

According to some embodiments of the present disclosure, as shown inFIG.3andFIG.4, a first branched finger electrode line212and a second branched finger electrode line213are connected to one end of the first finger electrode sub-line211close to the first interval2110. A third branched finger electrode line222and a fourth branched finger electrode line223are connected to one end of the second finger electrode sub-line221close to the second interval2210. The first branched finger electrode line212, the second branched finger electrode line213, the third branched finger electrode line222and the fourth branched finger electrode line223are configured to improve a current collection effect of the finger electrode line and preventing current collection effect of the finger electrode line from being affected by an excessively large width between the first interval2110and the second interval2210.

In the present disclosure, the current collection effect of the finger electrode line can be effectively improved by designing the first branched finger electrode line212and the second branched finger electrode line213at one end of the first finger electrode sub-line211close to the first interval2110and designing the third branched finger electrode line222and the fourth branched finger electrode line223at one end of the second finger electrode sub-line221close to the second interval2210.

According to some embodiments of the present disclosure, an angle α between the first branched finger electrode line212and the second branched finger electrode line213satisfies 0°<α<90°. A region of the angle α between the first branched finger electrode line212and the second branched finger electrode line213adapts to an offset curve of the second conductive line32. The angle α may be, for example, 5°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° or 85°, and may also be other values in the above range, which is not limited herein. An angle β between the third branched finger electrode line222and the fourth branched finger electrode line223satisfies 0°<β<90°. A region of the angle β between the third branched finger electrode line222and the fourth branched finger electrode line223adapts to an offset curve of the first conductive line31. The angle β may be, for example, 5°, 10°, 20°, 30°, 40°, 60°, 70°, 80° or 85°, and may also be other values in the above range, which is not limited herein.

The limitations on the angle α between the first branched finger electrode line212and the second branched finger electrode line213and the angle β between the third branched finger electrode line222and the fourth branched finger electrode line223can ensure that the first conductive line31and the second conductive line32may not contact the first finger electrode line21and the second finger electrode line22when being offset, and can also more effectively improve the current collection effect of the finger electrode line.

According to some embodiments of the present disclosure, as shown inFIG.5andFIG.6, a fifth branched finger electrode line214is connected to the end of the first finger electrode sub-line211close to the first interval2110, and the fifth branched finger electrode line214is located between the first branched finger electrode line212and the second branched finger electrode line213. A sixth branched finger electrode line224is connected to the end of the second finger electrode sub-line221close to the second interval2210, and the sixth branched finger electrode line224is located between the third branched finger electrode line222and the fourth branched finger electrode line223.

The current collection effect of the finger electrode line can be more effectively improved by further designing the fifth branched finger electrode line214between the first branched finger electrode line212and the second branched finger electrode line213and further designing the sixth branched finger electrode line224between the third branched finger electrode line222and the fourth branched finger electrode line223.

According to some embodiments of the present disclosure, lengths of the first branched finger electrode line212, the second branched finger electrode line213and the fifth branched finger electrode line214are equal, which can ensure that the end of the first finger electrode sub-line211close to the first interval2110can collect currents in all directions, and current collection capabilities in all directions are kept the same. Lengths of the third branched finger electrode line222, the fourth branched finger electrode line223and the sixth branched finger electrode line224are equal, which can ensure that the end of the second finger electrode sub-line221close to the second interval2210can collect currents in all directions, and current collection capabilities in all directions are kept the same.

According to some embodiments of the present disclosure, according to design requirements of photoelectric conversion efficiency of different IBC solar cells, one or more fifth branched finger electrode lines214may be provided, and one or more sixth branched finger electrode lines224may be provided.

The present disclosure further provides an IBC solar cell module. The IBC solar cell module includes the IBC solar cells described above, which can reduce manufacturing costs of the IBC solar cell module and a usage amount of metallized paste, and can also ensure photoelectric conversion efficiency of the solar cell. The IBC solar cells are electrically connected to form individual IBC solar cell string in an entirety or multi-slice (for example, ½-cut cells, ⅓-cut cells, ¼-cut cells) form. In some embodiments, the IBC solar cell module further includes a packaging material layer and a cover plate. The packaging material layer is configured to seal a plurality of IBC solar cell strings, and the cover plate covers the packaging material layer. For example, the packaging material layer may be made of an organic material, for example, ethylene vinyl acetate (EVA), polyolefin elastomer (POE) or polyethylene terephthalate (PET). The cover plate may be a cover plate with a light transmission function, for example, a glass cover plate or a plastic cover plate. As shown inFIG.1, the IBC solar cell includes a semiconductor substrate1, a plurality of finger electrode lines and a plurality of conductive lines3. Each finger electrode line2include a first finger electrode line21and a second finger electrode line22, and the first finger electrode line21and the second finger electrode line22are alternately arranged on the semiconductor substrate1. The conductive line3includes a first conductive line31and a second conductive line32, and the first conductive line31and the second conductive line32are alternately arranged. The first conductive line31is connected to the first finger electrode line21, and the first conductive line31is spaced apart from the second finger electrode line22. The second conductive line32is connected to the second finger electrode line22, and the second conductive line32is spaced apart from the first finger electrode line21.

The above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. For those skilled in the art, the present disclosure may have various modifications and variations. Any modifications, equivalent substitutions, improvements and the like made within the principle of the present disclosure should fall within the protection scope of the present disclosure.