TWI513019B - Solar cell and solar cell module - Google Patents

Description

Solar cell and solar cell module

The present invention relates to a photoelectric conversion device, and more particularly to a solar cell.

At present, since the interdigitated back contact solar cell (IBC Solar Cell) has high battery efficiency, it has become a trend in the development of solar cells. Please refer to FIG. 1 and FIG. 2 , which are respectively a partial rear view and a partial cross-sectional view of a solar cell with a conventional interdigitated back contact. The solar cell 100 with the interdigitated back contact mainly comprises an N-type substrate 102, an N ⁺ -type conductive layer 108, an anti-reflection layer 110, an N ⁺⁺ -type doping region 114 , a P ⁺ -type doping region 116 , a passivation layer 118 , N The electrode 120, the P-type electrode 122, the N-type bus electrode 126, and the P-type bus electrode 132.

In the solar cell 100, the N-type substrate 102 has a front side 104 and a back side 106, wherein the front side 104 and the back side 106 are respectively located on opposite sides of the N-type substrate 102. The front surface 104 is generally a light receiving surface of the solar cell 100, and is provided with a roughness 112 thereon to increase the amount of light incident. The N ⁺ -type conductive layer 108 is entirely provided on the front surface 104 as a front surface electric field (FSF) layer of the solar cell 100. The anti-reflective layer 110 is overlaid on the N ⁺ -type conductive layer 108 to avoid reflection of incident light.

The N ⁺⁺ type doped region 114 and the P ⁺ -type doped region 116 are respectively disposed in a partial region within the N-type substrate 102 and adjacent to the back surface 106. A passivation layer 118 overlies the back side 106. The passivation layer 118 has a plurality of openings 128 and 130 that expose a portion of the N ⁺⁺ -type doped region 114 and a portion of the P ⁺ -type doped region 116, respectively. The N-type electrode 120 and the N-type bus electrode 126, and the P-type electrode 122 and the P-type bus electrode 132 are disposed on the passivation layer 118, and are respectively doped with N ⁺⁺ type via the openings 128 and 130 of the passivation layer 118, respectively. Region 114 and P ⁺ doped region 116 are in contact. One end of each N-type electrode 120 is connected to the N-type bus electrode 126, and one end of each P-type electrode 122 is connected to the P-type bus electrode 132.

In the solar cell 100, since the N ⁺⁺ type doping region 114 and the P ⁺ -type doping region 116 are both disposed on the back surface 106 of the N-type substrate 102, in order to avoid the N ⁺⁺ type doping region 114 and the P ⁺ type doping The inter-doped regions 116 interact with each other due to mutual diffusion, and the N ⁺⁺ -type doped regions 114 and the P ⁺ -type doped regions 116 are separated from each other with an elongated interval 124 therebetween, as shown in FIG.

Referring again to FIG. 1 , the solar cell 100 has an electrode structure of a finger-shaped back contact and is usually fabricated by screen printing, wherein the finger-shaped N-type electrode 120 and the P-type electrode 122 are arranged in an interdigitated manner. Therefore, the N ⁺⁺ type doping layer 114 and the P ⁺ -type doping layer 116 which are respectively in contact with the N-type electrode 120 and the P-type electrode 122 are also generally arranged in a fork shape. Because the width of the P ⁺ -type doping region 116 of the solar cell 100 is much larger than the width of the N ⁺⁺ -type doping region 114, and the widths of the N-type electrode 120 and the P-type electrode 122 are also smaller than their corresponding N ^{+ respectively.} The width of the ⁺ -doped region 114 and the P ⁺ -type doped region 116, particularly the P-type electrode 122, is much smaller than the width of the P ⁺ -type doped region 116. Therefore, the P-type electrode 122 and the N-type electrode 120 are far apart from each other. As a result, the distance of the carrier in the lateral current from the N ⁺⁺ type doping layer 114 to the P ⁺ -type doping layer 116 is longer, which will result in a decrease in the efficiency of carrier collection, thereby causing the current of the solar cell 100. Density cannot be effectively improved, and the problem that the overall battery efficiency cannot be improved is derived.

Further, the material of the P-type electrode 122 is usually a silver aluminum paste. Since the metal component of the silver aluminum paste contains a large amount of silver, the production cost of the P-type electrode 122 of the solar cell 100 is high.

Therefore, an aspect of the present invention provides a solar cell, a method of manufacturing the same, and a solar cell module, wherein a current is collected by using a plurality of non-continuous conductive portions of a first electrode disposed on a back surface of the substrate, and then the first The conductive layer of the electrode conducts the current collected by the conductive portion to the bus electrode. In this way, the current collection efficiency of the solar cell can be improved.

Another aspect of the present invention provides a solar cell, a method of manufacturing the same, and a solar cell module, which are capable of effectively reducing the first electrode while achieving current collection efficiency by means of a dispersive and electrically conductive portion. The contact area between the metal and the interface of the semiconductor substrate also improves the electrical effect of the solar cell even if the area of the entire substrate back surface is increased.

Another aspect of the present invention provides a solar cell, a manufacturing method thereof and a solar cell module. Since the current collection efficiency of the solar cell is good, the open circuit voltage (Voc) of the solar cell can be improved, thereby improving the solar cell. Output Power.

Still another aspect of the present invention is to provide a solar cell and The manufacturing method and the solar cell module can reduce the amount of the relatively expensive conductive adhesive of the conductive portion of the first electrode, thereby reducing the manufacturing cost of the solar cell and the solar cell module.

A further aspect of the present invention provides a solar cell, a method of manufacturing the same, and a solar cell module, wherein a conductive layer of the first electrode can effectively reflect incident light that is incident from the front surface of the substrate to the back surface of the substrate, thereby improving the back surface of the substrate. Light reflectivity.

According to the above object of the present invention, a solar cell is proposed. The solar cell includes a substrate, at least one first doped region, at least one second doped region, a dielectric layer, at least one first electrode, and at least one second electrode. The substrate has a front surface and a back surface opposite to the front surface, and the substrate has a second conductivity type. The first doped region has a first conductivity type and is located within the substrate and adjacent to the back surface. The second doped region has a second conductivity type and is located within the substrate and adjacent to the back surface, wherein the second doped region is adjacent to the first doped region. The dielectric layer is on the back side and covers the first doped region and the second doped region. The dielectric layer has a plurality of first openings corresponding to the first doped regions, and at least one second openings corresponding to the second doped regions. The first electrode includes a plurality of conductive portions and a conductive layer, wherein the conductive portions are respectively located in the first opening and connected to the first doped region, and the conductive layer is located on the dielectric layer and connects the conductive portions. The materials of the conductive layer and the conductive portion are different from each other. The second electrode is located in the second opening and is connected to the second doping region.

According to an embodiment of the invention, the first opening is located on a side of the first doping region adjacent to the second doping region.

According to another embodiment of the present invention, the material of the conductive portion is Includes a mixture of silver and aluminum.

According to still another embodiment of the present invention, the material of the conductive layer is selected from the group consisting of aluminum, copper, lead and tin.

According to still another embodiment of the present invention, the conductive portions are not in contact with each other.

According to still another embodiment of the present invention, the conductive portion corresponds to a number of central portions of the first doped region that is less than a portion corresponding to a portion of the first doped region.

According to still another embodiment of the present invention, the conductive portion is superior in conductivity to the conductive layer.

According to still another embodiment of the present invention, the conductive portions are arranged in a two-dimensional manner.

According to still another embodiment of the present invention, the shape of the first opening includes any one of a circle, a polygon, a rectangle, a square, a rectangle, and an ellipse.

According to the above object of the present invention, a solar battery module is further proposed. The solar cell module comprises an upper plate, a lower plate, a solar cell as described above, and at least one layer of encapsulating material. The solar cell is disposed between the upper plate and the lower plate. At least one layer of encapsulating material is positioned between the upper and lower plates to bond the solar cells to the upper and lower plates.

100‧‧‧ solar cells

102‧‧‧N type substrate

104‧‧‧ positive

106‧‧‧Back

108‧‧‧N ⁺ type conductive layer

110‧‧‧Anti-reflective layer

112‧‧‧Rough structure

114‧‧‧N ⁺⁺ type doped area

116‧‧‧P ⁺ doped region

118‧‧‧ Passivation layer

120‧‧‧N type electrode

122‧‧‧P type electrode

124‧‧‧ interval

126‧‧‧N type bus electrode

128‧‧‧ openings

130‧‧‧Opening

132‧‧‧P type bus electrode

200‧‧‧Solar battery module

202‧‧‧ solar cells

204‧‧‧Upper board

206‧‧‧ Lower board

208‧‧‧Package material layer

210‧‧‧Package material layer

212‧‧‧Substrate

214‧‧‧ positive

216‧‧‧ back

218‧‧‧ electric field layer

220‧‧‧Anti-reflective layer

222‧‧‧Rough structure

224‧‧‧Second doped area

226‧‧‧First doped area

228‧‧‧ dielectric layer

230‧‧‧First opening

232‧‧‧Second opening

234‧‧‧Electrical Department

236‧‧‧second electrode

238‧‧‧Transmission layer

240‧‧‧First main bus electrode

242‧‧‧Second main bus electrode

244‧‧‧

246‧‧‧

248‧‧‧first electrode

250‧‧‧ interval

252‧‧‧ central part

254‧‧‧side part

The above and other objects, features, advantages and embodiments of the present invention will become more apparent and understood.

Figure 1 is a partial rear elevational view of a conventional prismatic back contact solar cell.

Figure 2 is a partial cross-sectional view showing a solar cell of a conventional interdigitated back contact.

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

Figure 4 is a rear elevational view of a solar cell in accordance with an embodiment of the present invention.

Figure 5 is a cross-sectional view showing a solar cell according to an embodiment of the present invention.

At present, in order to reduce the electrode manufacturing cost of the solar cell, there is a proposal to replace the silver-aluminum glue as an electrode material with copper glue, aluminum glue or other conductive glue. The present invention herein proposes a solar cell architecture that can reduce electrode fabrication costs while increasing current collection efficiency.

Please refer to FIG. 3, which is a cross-sectional view showing a solar cell module according to an embodiment of the present invention. In the present embodiment, the solar cell module 200 mainly includes an upper plate 204, a lower plate 206, a solar cell 202, and one or more layers of encapsulating material, such as encapsulating material layers 208 and 210.

As shown in FIG. 3, in the solar cell module 200, the solar cell 202 is disposed on the lower plate 206 and disposed under the upper plate 204. Therefore, the upper plate 204 is disposed above the lower plate 206, and the solar cell 202 is disposed between the lower plate 206 and the upper plate 204. In addition, the two layers of encapsulation material layers 208 and 210 Then, it is disposed between the upper plate 204 and the solar cell 202, and the lower plate 206 and the solar cell 202, respectively. The package of material layers 208 and 210 can be used to bond the solar cell 202 to the lower plate 206 and the upper plate 204 in a molten state by a high temperature press process.

Please refer to FIG. 4 and FIG. 5, which are respectively a rear view and a cross-sectional view of a solar cell according to an embodiment of the present invention. In some embodiments, the solar cell 202 can include a substrate 212, at least a first doped region 226, at least a second doped region 224, a dielectric layer 228, at least a first electrode 248, and at least a second electrode. 236. As shown in FIG. 5, the substrate 212 has a front surface 214 and a back surface 216. The front side 214 and the back side 216 are respectively located on opposite sides of the substrate 212, so the back side 216 is opposite to the front side 214. The material of the substrate 212 can be, for example, a semiconductor material such as germanium, and there is no design between the front surface 214 and the back surface 216 of the substrate 212. Further, the substrate 212 may have a second conductivity type. In an exemplary embodiment, the front side 214 of the substrate 212 may be roughened such that the front side 214 of the substrate 212 has a roughness 222, such as a pyramidal topography of a single crystal wafer, thereby enhancing the solar cell 202 for incidence. Light absorption efficiency.

The first doped region 226 is located within the substrate 212 and is adjacent to the back side 216 of the substrate 212. The first doped region 226 has a first conductivity type. In addition, the second doped region 224 is also located within the substrate 212, also adjacent the back side 216 of the substrate 212. Moreover, the second doping region 224 is adjacent to the first doping region 226. The second doping region 224 has a second conductivity type. In the present invention, the first conductivity type is different from the second conductivity type. In some embodiments, one of the first conductivity type and the second conductivity type may be a P type, and the other may be an N type. For example, the first conductivity type is a P type, and the second conductivity type is an N type. In a preferred embodiment, substrate 212 is N-type, first doped region 226 is of P ⁺ type, and second doped region 224 is of the N ⁺⁺ type. The first doped region 226 and the adjacent second doped region 224 have a space 250 therebetween to separate the first doped region 226 from the second doped region 224 to avoid the first doped region 226 and adjacent The second doped regions 224 interact with each other due to mutual diffusion.

The dielectric layer 228 is located on the back surface 216 of the substrate 212 and covers the first doped region 226 and the second doped region 224. The dielectric layer 228 can serve as a passivation layer and can be a one-layer or multi-layered multi-layer structure, thereby passivating the back surface 216 of the substrate 212 to improve the short-circuit current (Isc) and the open circuit voltage of the solar cell 202, thereby improving the solar cell. 202 photoelectric conversion efficiency. In addition, the dielectric layer 228 can also serve as an anti-reflective coating (ARC) layer to facilitate incident light entering the solar cell 202 from the back side 216 of the substrate 212.

As shown in FIG. 5, the dielectric layer 228 can have a plurality of first openings 230 and one or more second openings 232. The first openings 230 are disposed corresponding to the first doped regions 226, that is, the first openings 230 are disposed in the dielectric layer 228 and expose portions of the first doped regions 226. On the other hand, the second opening 232 is disposed corresponding to the second doping region 224, that is, the second opening 232 is disposed in the dielectric layer 228 and exposes a portion of the second doping region 224. In some embodiments, the first openings 230 may be located on a side of the first doped region 226 adjacent to the adjacent second doped region 224. In other embodiments, the first openings 230 may be disposed at a portion 254 corresponding to the central portion 252 of the first doped region 226 and the side portion 254 corresponding to the first doped region 226. Furthermore, these first openings 230 can be arranged, for example, in a two-dimensional manner. First opening 230 The shape may include, for example, any of a circle, a polygon, a rectangle, a square, a rectangle, and an ellipse, or any other shape.

The first electrode 248 is located on the back surface 216 of the substrate 212 and is disposed corresponding to the first doping region 226. Referring again to FIGS. 4 and 5, the first electrode 248 includes a plurality of conductive portions 234 and a conductive layer 238. The conductive portions 234 are connected to the first doping region 226 through the dielectric layer 228, that is, through the corresponding first openings 230 disposed in the dielectric layer 228, wherein the conductive portions 234 are connected. They are independent of each other and have no contact with each other, and thus exhibit a form of point contact as a whole with respect to the first doping region 226. These conductive portions 234 may be aligned, for example, in a two-dimensional manner corresponding to the first doped regions 226. Of course, the conductive portions 234 may also be disposed in a one-dimensional manner, for example, in a line manner, corresponding to the first doping region 226. In some embodiments, the number of central portions 252 of the conductive portions 234 corresponding to the first doped regions 226 is less than the number of the side portions 254 corresponding to the first doped regions 226, thereby being permeable to the first doped regions. The conductive portion 234 of the side portion 254 of the portion 226 strengthens the lateral current from the second doped region 224 to facilitate current collection, and can be disposed in a small amount at a central portion 252 where the lateral current is relatively small. The conductive portion 234 reduces the contact area of the electrodes and increases the passivation area of the dielectric layer 228, thereby improving the electrical effect. In an exemplary embodiment, each of the conductive portions 234 may have a diameter of about 60 μm and a height of about 20 μm, and the conductive portions 234 may be spaced apart from each other by about 200 μm. On the other hand, the conductive layer 238 is located on the dielectric layer 228 and covers the conductive portions 234, and is connected to the conductive portions 234, and the conductive portions 234 can be electrically connected to each other. Sexual connection.

In the present embodiment, the material of the conductive layer 238 is different from the material of the conductive portions 234. The conductivity of the conductive portion 234 is preferably superior to the conductivity of the conductive layer to facilitate collection of carriers in the substrate 212 to improve current collection efficiency. In some embodiments, the material of the conductive portion 234 may comprise a silver-aluminum mixture. In a preferred embodiment, the metal content of the silver-aluminum mixture comprising conductive portion 234 may comprise a higher level of silver and a lower level of aluminum, such as 95% by weight silver and 5% by weight aluminum. Moreover, in some embodiments, the material of the conductive layer 238 can be selected from the group consisting of aluminum, copper, lead, tin, and other electrically conductive metals and oxides thereof. In an exemplary embodiment, the conductive layer 238 is made of aluminum.

The solar cell 202 can be a finger-shaped back contact solar cell. Therefore, as shown in FIG. 4, the second electrode 236 is also disposed on the back surface 216 of the substrate 212 like the first electrode 248. Moreover, the second electrode 236 and the first electrode 248 are arranged in an interdigitated manner. The second electrode 236 is disposed corresponding to the second doping region 224. As shown in FIG. 5, the second electrode 236 passes through the dielectric layer 228, that is, through the second opening 232 disposed in the dielectric layer 228, and is connected to the second doping region 224. In some embodiments, the material of the second electrode 236 may comprise silver.

The solar cell 202 can further include a first main bus electrode 240 and a second main bus electrode 242. The first main bus electrode 240 is located on the back side 216 of the substrate 212 and is also disposed corresponding to the first doped region 226. Additionally, the first main bus electrode 240 is coupled to one end 246 of the conductive layer 238 of the first electrode 248. The second main bus electrode 242 is also located on the back of the substrate 212. 216, and corresponding to the second doping region 224. The second main bus electrode 242 is connected to one end 244 of the second electrode 236.

Referring again to FIG. 5, in the present embodiment, the solar cell 202 further includes an electric field layer 218. The electric field layer 218 can be overlaid on the front side 214 of the substrate 212 as a front surface electric field layer of the solar cell 202. In some embodiments, the electric field layer 218 can be an N+ type conductive layer. The potential and energy provided by the electric field layer 218 can drive the holes and electrons formed in the vicinity of the front surface 214 of the substrate 212 to move to the first doping region 226 and the second doping region 224 of the back surface 216, respectively. In addition, the solar cell 202 may further include an anti-reflection layer 220 according to product requirements. The anti-reflective layer 220 is overlaid on the electric field layer 218 to avoid reflection of incident light, thereby increasing the light incidence efficiency of the solar cell 202.

In the solar cell 202, current is collected by a plurality of non-continuous and electrically conductive portions 234 of the first electrode 248 disposed on the back surface 216 of the substrate 212, and the conductive layer 238 of the first electrode 248 is used to conduct the conductive portion. The current collected by portion 234 is to the first main bus electrode 240. Therefore, the current can be efficiently collected through the conductive portion 234 which is dispersed and electrically conductive, thereby improving the electrical effect of the solar cell 202. In addition, the arrangement of the distributed conductive portion 234 can also reduce the contact area between the first electrode 248 and the back surface 216 of the substrate 212, so that the overall passivation area of the dielectric layer 228 to the back surface 216 of the substrate 212 can be relatively increased. By reducing the carrier recombination, the electrical effect of the solar cell 202 can be further improved. Moreover, the embodiment can reduce the amount of the more expensive conductive material of the conductive portion 234 of the first electrode 248, thereby reducing the manufacturing cost of the solar cell 202. Moreover, the width of the conductive layer 238 of the first electrode 248 can be much larger than the diameter of the conductive portion 234. For example, conductive layer 238 can have a width of up to about 1400 [mu]m, while conductive portion 234 can be about 60 [mu]m directly. Thus, the placement of the conductive layer 238 facilitates reflection of incident light from the front side 214 of the substrate 212 to the back side 216 of the substrate 212, thereby increasing the light reflectivity of the back side 216 of the substrate 212.

In the above embodiment, the design of the electrode having the conductive portion and the conductive layer is only corresponding to the first doped region. However, in the present invention, the conductive portion and the conductive portion may be disposed only corresponding to the second doped region according to product requirements. An electrode having a conductive portion and a conductive layer is disposed at the same time as the electrode of the layer or the first doped region and the second doped region.

Referring to FIG. 4 and FIG. 5 again, in one embodiment, when a solar cell is fabricated, for example, the solar cell 202 of the above embodiment may be provided with the substrate 212 first. Next, in some embodiments, the front side 214 of the substrate 212 may be roughened according to product requirements, thereby forming a plurality of roughness structures 222 on the front side 214 of the substrate 212. In another embodiment, the back side 216 of the substrate 212 may also be roughened. In another embodiment, the solar cell 202 is a double-sided light-emitting type, and the front surface 214 and the back surface 216 of the substrate 212 can be roughened at the same time, so that the front surface 214 and the back surface 216 of the substrate 212 have a rough structure. Of course, in the back contact solar cell 202, that is, the positive and negative electrodes are all located on the back side, the back surface 216 of the substrate 212 is usually subjected to a flattening process, that is, a rough structure without a pyramid shape, so that the back surface The passivation effect of 216 after passivation can be further improved and can be transmitted through the flatter back surface 216. The incident light incident from the front surface 214 is more effectively reflected, and is absorbed and utilized in the substrate 212.

Next, a doping process can be performed on the front side 214 of the substrate 212 to form an electric field layer 218 in the substrate 212 near the front side 214. This electric field layer 218 extends over the entire front side 214. In one embodiment, in order to form the electric field layer 218, part of the dopant is removed at the doping generated by the back surface 216 of the substrate 212, and the surface may be selectively etched on the back surface 216 according to process requirements. Remove processing.

Next, a doping process can be performed on the back surface 216 of the substrate 212 to form at least one first doping region 226 and at least one second doping region 224 separated from each other in the substrate 212 near the back surface 216. As previously described, the first doped region 226 has a first conductivity type, such as a P ⁺ type, and the second doped region 224 has a second conductivity type, such as an N ⁺⁺ type. The second doped region 224 is adjacent to the first doped region 226, and the first doped region 226 has a spacing 250 between the adjacent second doped region 224. When performing the doping process on the back surface 216 of the substrate 212, a barrier layer (not shown) may be firstly disposed on the front surface 214 of the substrate 212 to utilize the barrier layer of the barrier layer to prevent the dopant of the doping process from entering the front surface 214. In the electric field layer 218. In some embodiments, to avoid formation of the electric field layer 218, and/or the first doped region 226 and the second doped region 224, the dopant enters the side of the substrate 212, resulting in the electric field layer 218 and the first doped region. 226 and the second doping region 224 are electrically connected, so that the unnecessary doping region in the substrate 212 can be removed by using, for example, etching, to remove the electric field layer 218 and the first doping while removing the barrier layer. An insulating process between the impurity region 226 and the second doping region 224.

Next, the dielectric layer 228 is formed on the back surface 216 of the substrate 212 by, for example, deposition, and the dielectric layer 228 is overlaid on the first doped region 226 and the second doped region 224. Dielectric layer 228 can serve as a passivation layer for back side 216 of substrate 212. In addition, the dielectric layer 228 can also serve as an anti-reflective coating for the back side 216 of the substrate 212. Next, the anti-reflective layer 220 is selectively formed on the electric field layer 218 by, for example, a deposition method. In practice, when the anti-reflective layer 220 is tantalum nitride, the tantalum nitride may passivate the electric field layer 218 of the front surface 214 of the substrate 212 to enhance the electrical effect of the solar cell 202.

Then, referring again to FIG. 5, the plurality of conductive portions 234 of the first electrode 248 on the first doping region 226 of the back surface 216 of the substrate 212 may be printed by using, for example, screen printing. A slurry of metal material. In some embodiments, the metal stock slurry used to make the conductive portion 234 can be, for example, a silver aluminum paste. Next, the conductive layer 238 of the first electrode 248 and the first main bus electrode 240 and the second doping region 224 on the first doping region 226 of the back surface 216 of the substrate 212 may be reused, for example, by screen printing or the like. Where the second electrode 236 and the second main bus electrode 242 are disposed, a slurry of a metal material is printed. Unlike the metal material slurry in which the conductive portion 234 is formed, the metal material slurry used to form the conductive layer 238 may be, for example, aluminum paste, copper paste, lead paste, tin paste, or a mixture thereof. The metal material slurry used for the second electrode 236 can be, for example, a silver paste. The metal material slurry used for the first main bus electrode 240 and the second main bus electrode 242 can be, for example, silver paste, copper paste, aluminum paste or silver aluminum paste, etc., which can be adjusted with each other as needed.

In some embodiments, when the first electrode 248 is fabricated, it can be set first. The metal paste of the conductive portion 234 is baked, and then the metal paste of the conductive portion 234 is baked. Then, the metal paste of the conductive layer 238 is disposed, and the metal paste of the conductive layer 238 is baked, and then the conductive portion 234 and the conductive layer are performed. Sintering of the metal slurry of 238. In other embodiments, the sintering of the metal paste of the conductive portion 234 and the conductive layer 238 may be directly performed after the metal paste of the conductive layer 238 is disposed. In still other embodiments, the metal paste of the conductive portion 234 may be first disposed, then the metal paste of the conductive portion 234 is sintered, then the metal paste of the conductive layer 238 is disposed, and the metal paste of the conductive layer 238 is baked. dry.

When the metal paste of the first electrode 248, the first main bus electrode 240, the second electrode 236 and the second main bus electrode 242 is sintered, the first electrode 248 can be passed through a sintering process with a temperature of eight to nine hundred degrees. The metal paste of the conductive portion 234 and the first main bus electrode 240, and the metal paste of the second electrode 236 and the second main bus electrode 242 respectively penetrate the dielectric layer 228, respectively, and the first doping region 226 and The second doping regions 224 are connected, thereby completing the arrangement of the first electrode 248, the first main bus electrode 240, the second electrode 236, and the second main bus electrode 242. The conductive layer 238 of the first electrode 234 is located on the dielectric layer 228 and connected to the conductive portion 234. Of course, in addition to the above-mentioned method of screen printing, the first opening 230 and the second opening 232 may be respectively formed on the dielectric layer 228 by laser or etching (plasma), and then by coating, Forming the first electrode 234 on the first doping region 226 and the first main bus electrode 240, and the second electrode 236 and the second main bus electrode 242 on the second doping region 224, respectively; The electrode paste having no ability to penetrate the dielectric layer 228 can be screen printed onto the first opening 230 and the second opening 232 by screen printing, and the related baking is performed. The electrode is formed by a sintering process. In addition, the first main bus electrode 240 and the second main bus electrode 242 may also be designed not to be in contact with the substrate 212, that is, between the first main bus electrode 240 and the second main bus electrode 242 and the substrate 212. The dielectric layers 228 are separated by the use of the two bus electrodes mainly to collect the current from the second electrode 236 of the plurality of first electrodes 248 and further conduct the conduction through the solder ribbon, and first When the main bus electrode 240 and the second main bus electrode 242 are not in contact with the substrate 212, it means that the passivation area of the back surface 216 of the substrate 212 can be increased, and the carrier recombination can be reduced, thereby improving the electrical effect.

According to the above embodiments, an advantage of the present invention is that the solar cell of the present invention collects current by using a plurality of non-continuous conductive portions of the first electrode disposed on the back surface of the substrate, and then uses the conductive layer of the first electrode to The current collected by the conductive portion is conducted to the bus electrode. Therefore, the current collection efficiency of the solar cell and the solar cell module to which it is applied can be improved.

It can be seen from the above embodiments that another advantage of the present invention is that the present invention can effectively reduce the metal in the first electrode of the solar cell under the current collecting efficiency by the arrangement of the dispersed and conductive conductive portion. The contact area of the interface of the semiconductor substrate, that is, the increase of the overall passivation area enhances the electrical effect, thereby further improving the current collection efficiency of the solar cell.

It can be seen from the above embodiments that another advantage of the present invention is that since the current collection efficiency of the solar cell of the present invention is good, the open circuit voltage of the solar cell can be increased, and the output power of the solar cell can be improved.

It can be seen from the above embodiments that another advantage of the present invention is that the solar cell and the solar cell can be reduced by reducing the amount of the more expensive conductive adhesive of the conductive portion of the first electrode of the solar cell by using the manufacturing method of the solar cell of the present invention. The manufacturing cost of the module. This conductive paste can also be referred to as a conductive paste, which is only used in the word difference, as described herein.

According to the above embodiments, another advantage of the present invention is that the conductive layer of the first electrode of the solar cell of the present invention can effectively reflect the incident light from the front surface of the substrate to the back surface of the substrate, thereby improving the light reflectance of the back surface of the substrate. .

While the present invention has been described above by way of example, it is not intended to be construed as a limitation of the scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

202‧‧‧ solar cells

216‧‧‧ back

224‧‧‧Second doped area

226‧‧‧First doped area

228‧‧‧ dielectric layer

230‧‧‧First opening

232‧‧‧Second opening

234‧‧‧Electrical Department

236‧‧‧second electrode

238‧‧‧Transmission layer

240‧‧‧First main bus electrode

242‧‧‧Second main bus electrode

244‧‧‧

246‧‧‧

248‧‧‧first electrode

250‧‧‧ interval

252‧‧‧ central part

254‧‧‧side part

Claims (10)

A solar cell comprising: a substrate having a front surface and a back surface opposite to the front surface, wherein the substrate has a second conductivity type; at least a first doped region having a first conductivity type and located in the substrate And being adjacent to the back surface; at least one second doped region having a second conductivity type and located in the substrate and adjacent to the back surface, wherein the second doping region is adjacent to the first doping region; a dielectric layer, Located on the back surface and covering the first doped region and the second doped region, wherein the dielectric layer has a plurality of first openings corresponding to the first doped regions, and at least one second opening corresponding to In the second doped region, the at least one first electrode includes a plurality of conductive portions and a conductive layer, wherein the conductive portions are respectively located in the first openings and connected to the first doped region, and the a conductive layer is disposed on the dielectric layer and connected to the conductive portions, wherein the conductive layer and the conductive portions are different from each other; and at least one second electrode is located in the second opening and the second doping Zone connection. The solar cell of claim 1, wherein the first openings are located on a side of the first doped region adjacent to the second doped region. The solar cell of claim 1, wherein the conductive portions are made of a silver-aluminum mixture. The solar cell of claim 1, wherein the conductive layer is made of a material selected from the group consisting of aluminum, copper, lead and tin. The solar cell of claim 1, wherein the conductive portions are not in contact with each other. The solar cell of claim 1, wherein the pair of conductive portions The number of central portions of the first doped region should be less than the number corresponding to the portion adjacent to the first doped region. The solar cell of claim 1, wherein the conductive portions are superior in conductivity to the conductive layer. The solar cell of claim 1, wherein the conductive portions are arranged in a two-dimensional manner. The solar cell of claim 1, wherein the shape of the first openings comprises any one of a circle, a polygon, a rectangle, a square, a rectangle, and an ellipse. A solar cell module comprising: an upper plate; a lower plate; a solar cell according to any one of claims 1 to 9, disposed between the upper plate and the lower plate; and at least one layer of encapsulating material, Located between the upper plate and the lower plate, the solar cell is combined with the upper plate and the lower plate.