TW201633553A - Solar cell, solar cell module and manufacturing method thereof - Google Patents

Abstract

A solar cell includes a p-n junction, a substrate, a transparent conductive film and a bus bar. The transparent conductive film is disposed on the surface of the substrate and an opening is disposed in the transparent conductive film. The bus bar fills up the opening so that its bottom surface is substantially level with the bottom surface of the transparent conductive film.

Description

Solar battery, solar battery module and manufacturing method thereof

The present invention relates to the field of solar cells, and more particularly to a solar cell having a transparent conductive film, a solar module, and a method of fabricating the same.

With the depletion of consumable energy, the development of alternative energy sources such as solar energy has become an important development direction in the world. Most of the industry is committed to developing solar cells with high conversion efficiency and low production cost.

In mainstream solar cells, a transparent conductive film, such as a transparent conductive film composed of an oxide, is generally disposed on the surface of the solar cell, so that the photocurrent can be more efficiently conducted to the metal electrode and the external load. Since the transparent conductive film is electrically connected to the metal electrode on the surface of the solar cell, the carrier generated inside the battery can not only directly flow from the inside of the semiconductor substrate to the metal electrode, but also can enter the transparent conductive film first, and then conduct to the metal electrode. . In such a case, the residence time of the carrier inside the semiconductor substrate can be reduced, thus increasing the current output.

However, there is still room for improvement in the above solar cell having a transparent conductive film. For example, the metal electrode is generally disposed on the transparent conductive film. Due to the poor adhesion between the metal electrode and the transparent conductive film, the metal electrode is easily peeled off in a subsequent process stage or use stage, thereby reducing solar energy. The reliability of the battery or the corresponding module.

In view of this, it is necessary to provide a solar cell with a transparent conductive film to solve It is a flaw in the prior art.

It is an object of the present invention to provide a solar cell that addresses the deficiencies found in the prior art.

Another object of the present invention is to provide a solar cell module including an improved solar cell to address the deficiencies found in the prior art.

It is still another object of the present invention to provide a method of fabricating a solar cell that can produce an improved solar cell to address the deficiencies found in the prior art.

In accordance with the above objects, an embodiment of the present invention discloses a solar cell comprising at least a PN junction, a substrate, a transparent conductive film, and a bus electrode. The transparent conductive film is provided on the surface of the substrate, and an opening is provided therein. The bus electrode fills the opening so that the bottom surface of the transparent conductive film is cut.

According to another embodiment of the present invention, a solar cell module is disclosed. The solar cell module includes at least a front plate, a back plate, a plurality of solar cells, and a frame. The front panel and the back panel are oppositely disposed, and the outer frame is disposed on the front panel and the periphery of the back panel. The solar cell is disposed between the front plate and the back plate, and each includes a PN junction, a substrate, a transparent conductive film, and a bus electrode. The transparent conductive film is provided on the surface of the substrate, and an opening is provided therein. The bus electrode fills the opening so that the bottom surface of the transparent conductive film is cut.

According to still another embodiment of the present invention, a method of fabricating a solar cell is disclosed. The method of manufacturing a solar cell includes the following steps: First, a mask is provided to cover a portion of the surface of the substrate. Then, under the mask cover, a transparent conductive film is formed on the surface of the substrate, and at the same time transparent An opening is formed in the conductive film. Then remove the mask. Finally, a bus electrode is formed to fill the opening, wherein the bottom surface of the bus electrode is cut to the bottom surface of the transparent conductive film.

100‧‧‧ solar cells

102‧‧‧Substrate

104‧‧‧ first surface

106‧‧‧second surface

108‧‧‧Nature amorphous semiconductor layer

110‧‧‧Amorphous semiconductor layer

112‧‧‧ Essential amorphous semiconductor layer

114‧‧‧Amorphous semiconductor layer

115‧‧‧ Conductive metal layer

116‧‧‧Electrode layer

117‧‧‧Concurrent electrode

118‧‧‧ finger electrode

120‧‧‧electrode layer

122‧‧‧Transparent conductive film

124‧‧‧metal paste layer

126‧‧‧ Conductive tape

128‧‧‧flat joint

130‧‧‧ mask

132‧‧‧Sedimentation process

134‧‧‧Doped area

140‧‧‧Solar battery module

142‧‧‧ front board

144‧‧‧ Backplane

146‧‧ ‧ coating

O‧‧‧ openings

Fig. 1 is a plan view showing a solar cell according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view of the solar cell taken along the line tangential to Fig. 1A-A'.

Fig. 3 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to another embodiment of the present invention.

Fig. 4 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to still another embodiment of the present invention.

Fig. 5 is a plan view showing a solar cell according to a second embodiment of the present invention.

Fig. 6 is a cross-sectional view of the solar cell taken along the line B-B' of Fig. 5.

Figure 7 is a cross-sectional view of a solar cell according to a tangential line taken along line B-B' of Figure 5, in accordance with another embodiment of the present invention.

Fig. 8 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to a third embodiment of the present invention.

9 to 12 are views showing a method of fabricating a solar cell according to an embodiment of the present invention.

Figure 13 is a partial cross-sectional view showing a solar cell module in accordance with an embodiment of the present invention.

In order to enable those skilled in the art to understand and practice the present invention, the solar cell, the solar cell module, and the method of fabricating the solar cell of the present invention will be described in detail below with reference to the drawings. It is to be noted that the scope of the present invention is defined by the scope of the appended claims, and is not limited to the embodiments disclosed herein. Therefore, changes and modifications may be made to the embodiments described below without departing from the spirit and scope of the invention. In addition, for the sake of brevity and clarity, The same or similar elements or devices are denoted by the same element symbols, and some of the conventional structure and process details will not be disclosed below. It should be noted that the drawings are for illustrative purposes and are not drawn exactly according to the original dimensions.

Referring to Fig. 1 and Fig. 2, there are shown a plan view and a cross-sectional view, respectively, of a solar cell according to a first embodiment of the present invention, wherein Fig. 2 is taken along a line A-A' of Fig. 1. As shown in FIGS. 1 and 2, the solar cell 100 includes at least a substrate 102, an intrinsic amorphous semiconductor layer 108, an amorphous semiconductor layer 110, a transparent conductive film 122, and a conductive metal layer 115. The substrate 102 has a first conductivity type, preferably an N type, and has at least one surface, such as the first surface 104, as a main light receiving surface for receiving sunlight. The intrinsic amorphous semiconductor layer 108, the amorphous semiconductor layer 110, and the transparent conductive film 122 are sequentially disposed on the first surface 104. An opening O is provided in the transparent conductive film 122, which exposes a portion of the amorphous semiconductor layer 110. The conductive metal layer 115 fills the opening O and directly contacts the amorphous semiconductor layer 110 exposed to the opening O. The conductive metal layer 115 and the amorphous semiconductor layer 110 have a flat junction, and the bottom surface of the conductive metal layer 115 substantially cuts the bottom surface of the transparent conductive film 122. It should be noted that the term "substantially aligned" as used herein means that the bottom surface of the bus electrode 115 is aligned or slightly deeper than the bottom surface of the transparent conductive film 122.

Specifically, the substrate 102 is a crystalline semiconductor substrate, and is, for example, a single crystal germanium substrate, a polycrystalline germanium substrate, or a III-V compound substrate, and is preferably a single crystal germanium substrate. The body of the intrinsic amorphous semiconductor layer 108 may be an intrinsic semiconductor, preferably an intrinsic amorphous silicon, which is used to repair defects present on the first surface 104. The amorphous semiconductor layer 110 has a second conductivity type different from the first conductivity type, for example, a P-type, such that a PN junction exists between the amorphous semiconductor layer 110 and the substrate 102. The body of the amorphous semiconductor layer 110 may be a semiconductor having a dopant, preferably an amorphous germanium having a P-type dopant. In addition, the constituent body of the transparent conductive film 122 may be an oxide, such as a transparent conductive oxide (TCO) such as indium tin oxide (ITO) or indium zinc oxide (IZO), but Not limited to this. Conductive The metal layer 115 may include the electrode layer 116 and the metal paste layer 124 stacked in sequence such that a portion of the electrode layer 116 is disposed between the substrate 102 and the metal paste layer 124 and completely covered by the metal paste layer 124. . The electrode layer 116 may further include the bus electrode 117 and the finger electrode 118, and presents a layout as shown in FIG. 1, but is not limited thereto.

One of the features of the present invention is that an opening O is provided in the transparent conductive film 122, so that the conductive metal layer 115 can be embedded in the transparent conductive film 122, and the conductive metal layer 115 can directly contact the amorphous semiconductor layer 110 exposed to the opening O. . Since the conductive metal layer 115 is embedded and fixed to the transparent conductive film 122, and the adhesion between the conductive metal layer 115 and the amorphous semiconductor layer 110 is superior to the adhesion between the conductive conductive layer 122 and the transparent conductive film 122, the conductive metal layer 115 is not easily The subsequent process phase or the use phase is stripped, so the reliability of the solar cell can be improved. In addition, another feature of the present invention is that the electrode layer 116 is preferably symmetrically disposed about the opening O such that stress can be evenly distributed on both sides of the opening O to reduce the occurrence of fragments.

The solar cell 100 described above may further include other components. Still referring to FIG. 2, for example, a low resistance conductive ribbon 126, such as a metal conductive strip, may be placed or applied over the top surface of the conductive metal layer 115 to further transfer current to an external load. The substrate 102 further includes a second surface 106 on which an intrinsic amorphous semiconductor layer 112, an amorphous semiconductor layer 114, and an electrode layer 120 are sequentially disposed. Further, a transparent conductive layer (not shown) or a conductive tape (not shown) may be selectively disposed on the second surface 106, but is not limited thereto. Furthermore, an anti-reflective layer (not shown) may be selectively disposed on the first surface 104 and/or the second surface 106 to reduce the light reflectivity. It should be noted that even if an anti-reflection layer is provided, it should be satisfied that the conductive metal layer 115 and the amorphous semiconductor layer 110 have a flat junction 128, and the bottom surface of the conductive metal layer 115 substantially aligns the bottom surface of the transparent conductive film 122.

In particular, the body of the intrinsic amorphous semiconductor layer 112 may be an intrinsic semiconductor, preferably an intrinsic amorphous germanium, which is used to repair defects present on the second surface 106. Amorphous semiconductor The conductivity type of the layer 114 is preferably the same as that of the substrate 102, that is, the first conductivity type, and the main body thereof may be a semiconductor having a dopant, preferably an amorphous germanium having an N-type dopant. The composition of electrode layer 120 can include silver, aluminum, or other suitable metal.

The solar cell of the present invention may be derived from other variations in addition to the above-described embodiments. These variations will be described below. It is to be noted that since the structure of the following modifications is substantially similar to the above-described embodiments, the following description will be made only with respect to the main differences, and similar elements and structures may be referred to with reference.

Fig. 3 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to another embodiment of the present invention. As shown in FIG. 3, the embodiment of FIG. 3 is a modification of the embodiment of FIG. 2, and the main difference between the two is that the bus electrode 117 (or the electrode layer 116) and the metal of the solar cell 100 of the present embodiment are different. The slurry layer 124 directly contacts the amorphous semiconductor layer 110 exposing the opening O, so that the bus electrode 117 and the metal paste layer 124 form a flat junction 128 with the amorphous semiconductor layer 110. Similarly, the bus electrodes 117 are preferably symmetrically disposed about the opening O such that stress can be evenly distributed on both sides of the opening O to reduce the occurrence of fragments. The solar cell 100 of the present embodiment, except that the bus electrode 117 does not completely fill the opening O, the features, arrangement locations, and material properties of the remaining components are similar to those of the above embodiment, and thus will not be described herein.

Fig. 4 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to still another embodiment of the present invention. As shown in FIG. 4, the embodiment of FIG. 4 is a variation of the embodiment of FIG. 2. The main difference between the two is that the metal paste layer 124 of the solar cell 100 of the present embodiment fills the opening O and directly contacts. The amorphous semiconductor layer 110 of the opening O is exposed such that the bus electrode 117 (or as the electrode layer 116) does not contact the amorphous semiconductor layer 110 at all. Further, the partial bus electrode 117 may protrude from the metal paste layer 124, but is not limited thereto. It should be noted that even if the partial bus electrode 117 protrudes from the metal paste layer 124, the bus electrode 117 is preferably centered on the opening O. Symmetrically placed, the stress can be evenly distributed on both sides of the opening O, reducing the occurrence of fragments. The solar cell 100 of the present embodiment, except that the bus electrode 117 does not directly contact the amorphous semiconductor layer 110, the features, arrangement positions, and material properties of the remaining components are similar to those of the above embodiment, and thus will not be described herein.

The first embodiment of the present invention and its modifications have been described above, but the present invention is not limited thereto. Hereinafter, a second embodiment of the present invention will be described. It is to be noted that the structure of the second embodiment described below is substantially similar to that of the first embodiment described above, and therefore only the main differences will be described below, and similar elements and structures may be referred to.

Referring to Figures 5 and 6, there are shown top and cross-sectional views, respectively, of a solar cell according to a second embodiment of the present invention, wherein Figure 6 is taken along line B-B' of Figure 5. The main difference between the second embodiment and the first embodiment is that the electrode layer 116 of the solar cell 100 of the second embodiment is a finger electrode 118, and does not include a bus electrode (not shown), and thus can be presented as Figure 5 shows the layout. In this case, the metal paste layer 124 in the conductive metal layer 115 covers a portion of each of the finger electrodes 118. Specifically, as shown in FIG. 6, the transparent conductive film 122 of the present embodiment is also provided with an opening O which exposes a portion of the amorphous semiconductor layer 110. The finger electrode 118 fills the opening O and directly contacts the amorphous semiconductor layer 110 exposed to the opening O. The finger electrode 118 and the amorphous semiconductor layer 110 have a flat junction 128 therebetween, and the bottom surface of the finger electrode 118 is aligned with the bottom surface of the transparent conductive film 122. The solar cell 100 of the present embodiment has similar features, arrangement positions, and material characteristics to the first embodiment except that the electrode layer is the finger electrode 118, and thus will not be described herein.

The second embodiment described above can also be derived from other variations. As shown in Fig. 7, it is a cross-sectional view of a solar cell according to a variation of the second embodiment of the present invention corresponding to the tangential line of Fig. 5B-B'. The main difference between this variant and the second embodiment described above is that the metal paste of the solar cell 100 The material layer 124 fills the opening O and directly contacts the amorphous semiconductor layer 110 exposing the opening O, so that the finger electrode 118 does not contact the amorphous semiconductor layer 110 at all. The solar cell 100 of the present embodiment is similar to the second embodiment except that the finger electrode 118 does not directly contact the amorphous semiconductor layer 110. The features, arrangement positions, and material properties of the other components are similar to those of the second embodiment. .

In the above embodiments, a heterojunction solar cell is used as the application target of the present invention, but the invention is not limited thereto. In particular, the solar cell may also be a homojunction solar cell, such as a single crystal germanium solar cell having a doped region, without departing from the scope and spirit of the invention. In the following, a homojunction solar cell will be described. It is to be noted that the structure of the following embodiment is substantially similar to that of the first embodiment described above, and therefore only the main differences will be described below, and similar elements and structures may be referred to.

Fig. 8 is a cross-sectional view showing a solar cell according to a tangential line of Fig. 1A-A' according to a third embodiment of the present invention. As shown in FIG. 8, the solar cell 100 includes at least a substrate 102, a doped region 134, a transparent conductive film 122, and a conductive metal layer 115, which may optionally further include a conductive strip 126, an electrode layer 120, and an anti-reflection layer ( The figure is not shown). The substrate 102 is a crystalline semiconductor substrate, for example, a single crystal germanium substrate, a polycrystalline germanium substrate, or a III-V compound substrate, and is preferably a single crystal germanium substrate. The substrate 102 has at least one surface, such as the first surface 104, as the primary light receiving surface for receiving sunlight. The doped regions 134 are disposed within the substrate 102, and both preferably have different conductivity types to form a PN junction therebetween. Similar to the first embodiment described above, the transparent conductive film 122 is provided with an opening O which exposes a portion of the substrate 102 (or is considered to expose a portion of the doped region 134). The conductive metal layer 115 fills the opening O and directly contacts the substrate 102 exposed to the opening O (or is considered to be the doped region 134). The conductive metal layer 115 and the substrate 102 have a flat junction 128 therebetween, and the bottom surface of the conductive metal layer 115 is aligned with the bottom surface of the transparent conductive film 122. The solar cell 100 of the present embodiment is similar to the first embodiment except that the doping region 134 is provided, and the features, arrangement positions, and material properties of the remaining components are not described herein.

In order to enable those skilled in the art to practice the invention, the method of making the solar cell of the present invention will be described in detail below with reference to the drawings.

9 to 12 are views showing a method of fabricating a solar cell according to an embodiment of the present invention. First, as shown in Fig. 9 and Fig. 10, Fig. 10 is a cross-sectional view taken along line C-C' in Fig. 9. A substrate 102 is first provided having at least one surface. In particular, the substrate 102 has two opposing first and second surfaces 104, 106. On the first surface 104 and the second surface 106, the intrinsic amorphous semiconductor layers 108, 112 and the amorphous semiconductor layers 110, 114 are sequentially stacked, respectively. The intrinsic amorphous semiconductor layers 108, 112 and the amorphous semiconductor layers 110, 114 may be an intrinsic amorphous germanium layer and a doped amorphous germanium layer, respectively. Specifically, one of the amorphous semiconductor layers 110, 114 has the same conductivity type as the substrate 102, and the other is different. Preferably, the substrate 102 and the amorphous semiconductor layer 110 have a first conductivity type, such as an N type, and the amorphous semiconductor layer 114 has a second conductivity type, such as a P type. Next, a mask 130, such as a hard plate or photoresist, is provided to cover a portion of the first surface 104. Specifically, the mask 130 is strip-shaped and directly contacts a portion of the amorphous semiconductor layer 110, but the present invention is not limited thereto. According to other requirements, the mask 130 may also be curved or discontinuous, and the mask 130 may not directly contact the amorphous semiconductor layer 110, resulting in a gap therebetween (not shown).

As shown in FIG. 11, a deposition process 132 is performed while forming a transparent conductive film 122 on the amorphous semiconductor layer 110 and on the top surface of the mask 130. It is to be noted that since part of the amorphous semiconductor layer 110 is covered by the mask 130, the transparent conductive film 122 is not deposited to the covered amorphous semiconductor layer 110.

The mask 130 is then removed to form the structure as shown in FIG. At this time, the opening O exposes a portion of the amorphous semiconductor layer 110. It should be noted here that this embodiment utilizes the shielding In a manner, the openings O are formed synchronously in the deposition process 132, so that no additional opening process is necessary.

Finally, similarly as shown in FIGS. 1 and 2, a conductive metal layer 115 is formed to fill the opening O, wherein the bottom surface of the conductive metal layer 115 is aligned with the bottom surface of the transparent conductive film 122. Specifically, forming the conductive metal layer 115 may include the following steps. First, a conductive paste (not shown), such as a silver paste, is formed on the first surface 104 by screen printing or other suitable process to cover a portion of the transparent conductive film 122. Thereafter, sintering is performed to form a solid electrode layer 116 as shown in FIG. Then, another conductive paste is screen printed on the first surface 104 to cover a portion of the electrode layer 116, followed by sintering to form a metal paste layer 124. It should be noted that the conductive paste used to form the metal paste layer 124 is preferably a low temperature conductive paste, and the sintering temperature thereof may preferably be lower than 230 ° C.

Compared with the laser opening process, part of the amorphous semiconductor layer 110 or the substrate 102 is easily removed by the laser or loses the original electrical property. One of the features of this embodiment is that the opening O is in the deposition process 132. The transparent conductive film 122 is simultaneously formed, so that the loss of the light receiving area can be effectively avoided, and the current output of the solar cell is improved.

It should be noted here that the concept of the above solar cell fabrication method is also applicable to the fabrication of a homojunction solar cell as shown in FIG. Specifically, the intrinsic amorphous semiconductor layer and the amorphous semiconductor layer are not disposed on the substrate. Instead, a doping process is performed before the mask is provided to form a doped region in the substrate adjacent to the surface, and the conductivity type of the doped region is different from the conductivity type of the substrate. Therefore, after the conductive metal layer is formed, the doped region directly contacts the conductive metal layer, and the doped region and the conductive metal layer have a flat junction.

The invention also provides a solar cell module comprising the improved solar cell described above. In the following embodiments, the structure of the solar cell module will be described.

Please refer to FIG. 13, which is a partial cross-sectional view showing a solar cell module according to an embodiment of the present invention. The solar cell module 140 includes a front plate 142, a back plate 144, a plurality of solar cells 100, and a frame (not shown). The front plate 142 is disposed opposite to the back plate 144, and the solar cell 100 is disposed between the front plate 142 and the back plate 144. The outer frame is disposed around the front plate 142 and the back plate 144.

Specifically, each solar cell 100 is connected to each other in series and/or in parallel by a conductive strip 126. A cover layer 146 is also disposed between the front plate 142 and the back plate 144 such that the front plate 142 is bonded to the back plate 144. The cladding layer 146 can also hold the solar cell 100 and the conductive strip 126 to prevent the solar cell 100 and the conductive strip 126 from coming into direct contact with the outside. The material of the coating layer 146 may be a polymer copolymer such as ethylene vinyl acetate (EVA) or an ionomer, but is not limited thereto. Similarly, the solar cell 100 in the solar cell module 140 has the same structure as the first embodiment described above. Specifically, each solar cell 100 includes at least a substrate 102, an intrinsic amorphous semiconductor layer 108, 112, an amorphous semiconductor layer 110, 114, a transparent conductive film 122, and a conductive metal layer (not shown), which may also be selectively Also included is an anti-reflection layer (not shown). In addition, in order to provide different output voltages and currents, each solar cell 100 in the solar cell module 140 may be suitably connected in series, in parallel, or a combination of the two.

In summary, the present invention provides a solar cell, a solar cell module, and a method of fabricating the same. The conductive metal layer of the solar cell can be embedded in the transparent conductive film, and the conductive metal layer can directly contact the amorphous semiconductor layer or the substrate exposed to the opening, so the conductive metal layer is not easily peeled off in a subsequent process stage or use stage. This further improves the reliability of the solar cell. In addition, the electrode layers are preferably symmetrically disposed about the opening, so that stress can be evenly distributed on both sides of the opening to reduce the occurrence of fragments. Moreover, since the opening is formed simultaneously with the transparent conductive layer in the deposition process, the laser opening process can be discarded, the loss of the light receiving area is effectively avoided, and the current output of the solar cell is improved.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100‧‧‧ solar cells

102‧‧‧Substrate

104‧‧‧ first surface

106‧‧‧second surface

108‧‧‧Nature amorphous semiconductor layer

110‧‧‧Amorphous semiconductor layer

112‧‧‧ Essential amorphous semiconductor layer

114‧‧‧Amorphous semiconductor layer

115‧‧‧ Conductive metal layer

117‧‧‧Concurrent electrode

120‧‧‧electrode layer

122‧‧‧Transparent conductive film

124‧‧‧metal paste layer

126‧‧‧ Conductive tape

128‧‧‧flat joint

O‧‧‧ openings

Claims (20)

A solar cell having a PN junction, wherein the solar cell comprises: a substrate having a surface; a transparent conductive film disposed on the surface, wherein the transparent conductive film is provided with an opening; and a bus electrode, filling The opening is filled, wherein a bottom surface of the bus electrode is substantially aligned with a bottom surface of the transparent conductive film. The solar cell of claim 1, wherein a portion of the substrate directly contacts the bus electrode. The solar cell of claim 1, wherein the bus electrode comprises an electrode layer and a metal paste layer. The solar cell of claim 3, wherein the electrode layer is disposed between the metal paste layer and the substrate. The solar cell of claim 3, wherein a portion of the substrate directly contacts the electrode layer and/or the metal paste layer. The solar cell of claim 3, wherein the electrode layer and/or the metal paste layer fills the opening. The solar cell of claim 3, further comprising a conductive strip disposed on a top surface of the metal paste layer. The solar cell of claim 1, further comprising an amorphous semiconductor layer disposed on the surface, wherein the amorphous semiconductor layer exposed to the opening directly contacts the bus electrode, the amorphous semiconductor layer There is a flat junction between the bus electrode and the bus electrode. The solar cell of claim 8, wherein the amorphous semiconductor layer has a conductivity type different from that of the substrate. The solar cell of claim 1, further comprising a doped region disposed in the substrate adjacent to the surface, wherein the doped region exposed to the opening directly contacts the bus electrode, There is a flat junction between the doped region and the bus electrode. A solar cell module comprising: a front plate; a back plate disposed opposite the front plate; a plurality of solar cells disposed between the front plate and the back plate, wherein each of the solar cells has a PN junction And each of the solar cells includes: a substrate having a surface; a transparent conductive film disposed on the surface, wherein the transparent conductive film is provided with an opening; and a bus electrode filling the opening, wherein the bus electrode The bottom surface is substantially aligned with the bottom surface of the transparent conductive film; and an outer frame is disposed on the front plate and the periphery of the back plate. The solar cell module of claim 11, wherein the bus electrode comprises an electrode layer and a metal paste layer, wherein the electrode layer is disposed between the metal paste layer and the substrate. The solar cell module of claim 11, further comprising an amorphous semiconductor layer disposed on the surface, wherein the amorphous semiconductor layer exposed to the opening directly contacts the bus electrode, the amorphous There is a flat junction between the semiconductor layer and the bus electrode. The solar cell module of claim 11, further comprising a doped region disposed in the substrate adjacent to the surface, wherein the doped region directly contacts the bus electrode when exposed to the opening, There is a flat junction between the doped region and the bus electrode. A solar cell manufacturing method comprising: providing a substrate having a surface; providing a mask to cover a portion of the surface; forming a transparent conductive film on the surface under the covering of the mask, Forming an opening in the transparent conductive film; removing the mask; and forming a bus electrode to fill the opening, wherein a bottom surface of the bus electrode is substantially aligned with a bottom surface of the transparent conductive film. The solar cell manufacturing method according to claim 15, wherein the transparent conductive film is simultaneously formed on the top surface of the mask when the transparent conductive film is formed. The method for manufacturing a solar cell according to claim 15, wherein the step of forming the bus electrode comprises: forming an electrode layer on the surface to cover a portion of the transparent conductive film; forming a low temperature conductive paste on the Surfacely covering a portion of the electrode layer; and sintering the low temperature conductive paste, wherein the sintering temperature is lower than 230 °C. The solar cell manufacturing method of claim 15, wherein before the mask is provided, an intrinsic amorphous semiconductor layer and an amorphous semiconductor layer are sequentially formed on the surface, and the amorphous semiconductor layer is The conductivity type is different from the conductivity type of the substrate. The solar cell manufacturing method of claim 18, wherein after the bus electrode is formed, a part of the amorphous semiconductor layer exposes the opening and directly contacts the bus electrode, and the amorphous semiconductor layer and the bus electrode There is a flat joint. The solar cell manufacturing method of claim 15, further comprising forming a doped region in the substrate, wherein after forming the bus electrode, a portion of the doped region exposes the opening and directly contacts the confluent The electrode has a flat junction between the doped region and the bus electrode.