TW202002319A - Solar cell and manufacturing method thereof capable of avoiding structural wearing and increasing yield - Google Patents

Abstract

Provided is a method of making solar cells, which includes the following steps: (A) providing a semi-finished solar cell product including a substrate and an anti-reflection layer, wherein the substrate has an illuminated face and a non-illuminated face on the opposite sides, a plurality of perforations formed to penetrate through the illuminated face and the non-illuminated face and disposed at intervals, and the anti-reflection layer is arranged on the illuminated face; and (B) fabricating a conductive unit in the semi-finished solar cell product, wherein the conductive unit includes a plurality of first electrodes respectively disposed in the perforations, a plurality of second electrodes respectively disposed on the non-illuminated face, and a conductive layer disposed on the non-illuminated face. The first electrode protrudes out of the non-illuminated face, and a portion of each second electrode overlaps the conductive layer. The distance from an end surface of the first electrode protruding out of the non-illuminated face to the non-illuminated face is substantially equal to the thickness of a portion where the second electrode overlaps the conductive layer.

Description

Solar cell and its manufacturing method

The invention relates to a solar cell and a manufacturing method thereof, in particular to a solar cell capable of avoiding structural wear and improving yield, and a method of manufacturing the solar cell.

In recent years, with the rising awareness of environmental protection, solar cells are regarded as an important development technology for renewable energy. In the manufacturing process of solar cells, as each solar cell is completed and ready to be shipped to the back-end process, because the solar cells are often transported in a stacking manner, the stacked solar cells are prone to each other due to vibration. Friction causes part of the structure to wear out, so that the yield is not ideal.

Therefore, the object of the present invention is to provide a solar cell that can avoid structural wear and improve yield.

Therefore, the object of the present invention is to provide a manufacturing method for manufacturing the aforementioned solar cell, so as to reduce the structural wear during transportation.

Therefore, a method for manufacturing a solar cell of the present invention includes the following steps: (A) providing a semi-finished solar cell product including a substrate and an anti-reflection layer, the substrate having a light-receiving surface and a non-reflective layer on opposite sides A light-receiving surface, and a plurality of spaced-apart through-holes are formed through the light-receiving surface and the non-light-receiving surface, and the anti-reflection layer is provided on the light-receiving surface; A first electrode disposed on the perforations, a plurality of second electrodes disposed on the non-light-receiving surface of the substrate, and a conductive layer disposed on the non-light-receiving surface of the substrate, the first electrodes protruding from the non-perforated surface Outside the light-receiving surface, and a portion of each second electrode overlaps with the conductive layer, the distance from the end surface of the first electrodes protruding from the non-light-receiving surface to the non-light-receiving surface is substantially equal to the overlapping area of the second electrode and the conductive layer thickness.

In some implementations, the step (B) includes a step (B1), in which the first electrode and the second electrode are made by the same screen printing process, so that the second The thickness of the electrode is smaller than the distance from the end surface of the first electrode protruding from the non-light-receiving surface to the non-light-receiving surface.

In some embodiments, the step (B) further includes a step (B2) after the step (B1). In the step (B2), the conductive layer is screen printed on the screen by another screen printing process. On the non-light-receiving surface and the second electrodes, the conductive layer covers the non-light-receiving surface and overlaps a part of each second electrode.

In some embodiments, a first screen structure is further provided in step (A). The first screen structure includes a first mesh layer and a first disposed on the bottom surface of the first mesh layer A barrier layer, and a plurality of second barrier layers spaced on the bottom surface of the first barrier layer, the first barrier layer defines a plurality of first openings corresponding to the perforations and a plurality of corresponding to the non-light-receiving surface, respectively A second opening, the second barrier layer defines a plurality of third openings respectively corresponding to the first openings, and the first mesh layer has a first thickness, and the bottom surface of the first mesh layer reaches the first The bottom layer of the barrier layer has a second thickness, and the second barrier layer has a third thickness. In step (B1), the second barrier layer is pressed against the non-light-receiving surface and adjacent to the perforation, and the first An end of the barrier layer away from the second barrier layer is pressed against the non-light-receiving surface and away from the perforation, so that the first electrodes are coated on the first opening and the third opening of the first screen structure on the Through holes, and the second electrodes are simultaneously coated on the non-light-receiving surface through the second openings of the first screen structure, and the distance from the end surface of each first electrode to the non-light-receiving surface is equal to the first A thickness, the sum of the second thickness and the third thickness, and the thickness of each second electrode is equal to the sum of the second thickness and the third thickness.

In some embodiments, a second screen structure is further provided in step (A), the second screen structure includes a second mesh layer, and a third barrier layer fixed to the second mesh layer The third barrier layer defines a fourth opening. In step (B2), the third barrier layer shields the first electrodes and part of the second electrodes. The conductive layer passes through the first The fourth opening of the two screen structure corresponds to the portion of the non-light-receiving surface that is not shielded by the third barrier layer, and the conductive layer partially overlaps with each second electrode, and the conductive layer and the second electrode The thickness at the overlap is equal to the sum of the first thickness, the second thickness, and the third thickness.

In some embodiments, in step (B2), the difference between the end surface of each first electrode and the end surface where the corresponding second electrode overlaps the conductive layer is less than 15 microns.

In some embodiments, the height of each first electrode is higher than the height of the corresponding second electrode, and the difference between the end surface of the first electrode and the end surface of the corresponding second electrode is greater than 5 microns.

Therefore, the solar cell manufactured by the method according to the present invention includes: a substrate, an anti-reflection layer, a conductive unit and an insulating layer. The substrate includes a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer and having a majority carrier different from the first semiconductor layer. The first semiconductor layer has a non-light-receiving surface, and the first The two semiconductor layers have a light-receiving surface opposite to the non-light-receiving surface, and the substrate forms a plurality of spaced-apart through-holes that penetrate the light-receiving surface and the non-light-receiving surface. The anti-reflection layer is prepared on the light-receiving surface. The conductive unit includes a plurality of first electrodes disposed on the through holes, a plurality of second electrodes disposed on the non-light-receiving surface of the substrate, and a conductive layer disposed on the non-light-receiving surface of the substrate, the first The electrode protrudes out of the non-light-receiving surface, and a portion of each second electrode overlaps with the conductive layer, and the distance from the end surface of the first electrode protruding from the non-light-receiving surface to the non-light-receiving surface is substantially equal to the second electrode and the The thickness where the conductive layers overlap. The insulating layer is disposed in the through holes and bounds between the substrate and the first electrodes to electrically insulate the first electrode from the first semiconductor layer.

The effect of the invention is that the solar cell first screen-prints the first electrodes and the second electrodes on the substrate, and by controlling the thickness of the second electrodes to be smaller than the thickness of the first electrodes, Then, the conductive layer is made by the second screen printing, so that the thickness of the overlap between the conductive layer of the second screen printing and the second electrode is equal to the distance from the end surface of the first electrode to the non-light-receiving surface, The first electrodes are substantially flush with the conductive layer. Therefore, during the transportation of the solar cells in a stacking mode, the stacked solar cells can avoid the first electrode and the conductive layer. Some of the structures are more protruding and cause friction damage, which improves production yield.

1 to 3, an embodiment of the solar cell 1 of the present invention includes a substrate 11, an anti-reflection layer 12, a conductive unit 13, a plurality of insulating layers 14 and a conductive layer 15. In this embodiment, the solar cell 1 is an example of a metal-wrap-through solar cell (MWT Solar Cell), and a plurality of solar cells 1 are combined to form a solar cell module. It can be used for photoelectric conversion to provide power. FIG. 1 is a schematic bottom view of the solar cell 1, FIG. 2 is a schematic top view of the solar cell 1, and FIG. 3 is a schematic side view of the solar cell 1.

Referring to FIG. 3, the substrate 11 includes a first semiconductor layer 111, and a second carrier is formed by the first semiconductor layer 111 by doping a heterogeneous component by, for example, diffusion and the majority carrier is different from the first semiconductor layer 111 In the semiconductor layer 112, the first semiconductor layer 111 has a non-light-receiving surface 113, and the second semiconductor layer 112 has a light-receiving surface 114 opposite to the non-light-receiving surface 113, the substrate 11 forms a plurality of through the non-light-receiving surface 113 and the The light-receiving surface 114 and the through holes 115 arranged at intervals. In this embodiment, the first semiconductor layer 111 is exemplified by a silicon-based P-type semiconductor layer, and the second semiconductor layer 112 is exemplified by a silicon-based N-type semiconductor layer, thereby forming a PN junction, and the first semiconductor layer The bottom surface of 111 is the non-light-receiving surface 113, and the top surface of the second semiconductor layer 112 is the light-receiving surface 114. In use, the light-receiving surface 114 receives incident light toward the light source. In addition, the light-receiving surface 114 preferably forms a rough surface or a patterned surface to improve anti-reflection characteristics.

Referring to FIG. 3, the anti-reflection layer 12 is prepared on the light-receiving surface 114, and can be made into a single-layer or multi-layer structure through the selection of appropriate materials. The configuration of the refractive index allows the anti-reflection layer 12 to change the incident angle of incident light so that The amount of incident light entering the substrate 11 is increased to further improve the photoelectric conversion efficiency. The material of the anti-reflection layer 12 is, for example, silicon nitride, but it is not limited to this material.

Referring to FIG. 3, the conductive unit 13 includes a plurality of first electrodes 131 respectively disposed on the through holes 115, a plurality of second electrodes 132 disposed on the non-light-receiving surface 113 of the substrate 11, and a second electrode 132 disposed on the substrate 11 In the conductive layer 133 of the non-light-receiving surface 113, the first electrodes 131 protrude out of the non-light-receiving surface 113, and a portion of each second electrode 132 overlaps the conductive layer 133, and the first electrodes 131 protrude from the non-light-receiving surface 113 The distance from the end surface of the light receiving surface 113 (marked A in the figure) to the non-light receiving surface 113 is substantially equal to the thickness of the overlapping position of the second electrode 132 and the conductive layer 133 (marked B in the figure), so that the first electrodes 131 The end surface A of the conductive layer 133 is substantially flush with the protrusion B of the conductive layer 133, so that when stacking multiple solar cells 1, the structural friction damage caused by the protruding structure of the first electrode 131 or the conductive layer 133 can be avoided . In this embodiment, the first electrodes 131 are negative electrodes. Specifically, each first electrode 131 is connected to the second semiconductor layer 112 and the conductive layer 15 (see FIG. 3 for the first electrodes 131 Top side position), so that the electron carriers accumulated in the second semiconductor layer 112 are led out from the first electrodes 131, and the second electrodes 132 are positive electrodes, that is, each second electrode 132 is connected In the first semiconductor layer 111, the hole carriers gathered in the first semiconductor layer 111 are led out from the second electrodes 132, that is, two adjacent solar cells 1 can pass through the first electrodes 131 and The second electrodes 132 are electrically connected or provide electrical equipment power.

Referring to FIG. 3, the insulating layer 14 is disposed in the through holes 115 and bounded between the substrate 11 and the first electrodes 131 to electrically insulate the first electrode 131 from the first semiconductor layer 111. In addition, the conductive layer 15 is made of metal with a conductive function and the conductive layer 15 is transparent for incident light to penetrate. The conductive layer 15 is disposed on the anti-reflection layer 12 and connected to the first electrodes 131 for collecting the electron carriers of the second semiconductor layer 112 and conducting the electron carriers to the first electrodes 131. However, the conductive layer 15 is not limited to being transparent, and the conductive layer 15 may also be non-transparent and distributed in a pattern on the anti-reflection layer 12.

Referring to FIG. 4, a preferred embodiment of the manufacturing method of the solar cell 1 of the present invention sequentially includes the step S01 of providing a solar cell semi-finished product, a first screen structure 2 and a second screen structure 3 in the solar cell semi-finished product Step S02 of manufacturing the conductive unit 13 and step S03 of baking and sintering the conductive unit 13.

Referring to FIG. 5 and related drawings, the following first describes the manufacturing process of the solar cell semi-finished product provided by step S01.

Referring to FIG. 6, in step S011, a substrate 11 which is originally a flat surface is subjected to surface roughening or patterning to form the substrate 11 having a rough surface, so that the surface of the substrate 11 is uneven. In this way, the reflection angle of the incident light is changed, so that the incident light can enter the substrate 11 again, thereby increasing the amount of incident light. The substrate 11 is, for example, a P-type silicon wafer, so the step S011 is to roughen the P-type silicon wafer.

Referring to FIG. 7, in step S012, the entire surface of the substrate 11 is diffused and doped with a phosphorus-containing component, so that the substrate 11 is converted from a P-type silicon wafer to form the first semiconductor layer 111 that is divided into P-type And the N-type structure of the second semiconductor layer 112, and the first semiconductor layer 111 and the second semiconductor layer 112 form a PN junction, whereby when incident light is incident on the PN junction, the PN junction is excited The pair of electron holes at the junction makes the electron carriers and the hole carriers separate from each other to form a photocurrent. In addition, it should be noted that since this step is to fabricate the second semiconductor layer 112 by diffusion, the product layer 116, that is, the phosphorus-containing oxide layer, will also be formed on the outer surface of the second semiconductor layer 112.

Referring to FIG. 8, in step S013, the through holes 115 are formed on the substrate 11 by means of laser for subsequent fabrication of the first electrodes 131 (see FIG. 3). The method of 131 (see FIG. 3) can conduct the photocurrent of the second semiconductor layer 112 to the back of the solar cell 1 (see FIG. 3) to avoid excessive unnecessary structures occupying the illuminated area of the light receiving surface 114.

Referring to FIG. 8 and FIG. 9, in step S014, the product layer 116 is removed by etching, especially the portion of the light-receiving surface 114 to increase the probability of incident light reaching the P-N junction. In addition, most of the second semiconductor layer 112 is also removed, and only the portion corresponding to the light-receiving surface 114 remains.

Referring to FIGS. 10 and 11, in step S015, the surface of the substrate 11 (see FIG. 3) is passivated, so that the hole walls of the perforations 115 (see FIG. 3) form an insulating layer 14, and after the passivation step, The anti-reflective layer 12 is prepared on the light-receiving surface 114, and through different refractive index media, incident light can more easily penetrate into the first semiconductor layer 111 and the second semiconductor layer 112 and reduce the reflection characteristics, according to which, the completion of the Semi-finished solar cells.

Referring to FIGS. 4 and 5 and related drawings, the following describes the specific process of manufacturing the conductive unit 13 in steps S02 and S03. This step S02 can be further divided into the step S021 of manufacturing the first electrodes 131 and the second electrodes 132, And the subsequent step S022 of manufacturing the conductive layer 133.

Referring to FIGS. 12 to 14, in the step S021, the first screen structure 2 is used to perform a screen printing process to produce the first electrodes 131 and the second electrodes 132. The first screen structure 2 includes a The first mesh layer 21, a first barrier layer 22 disposed on the bottom surface of the first mesh layer 21, and a plurality of second barrier layers 23 disposed on the bottom surface of the first barrier layer 22 in this embodiment In an example, the first barrier layer 22 and the second barrier layer 23 are integrally formed. The first mesh layer 21 has a non-contact surface 211, a contact surface 212 opposite to the non-contact surface 211, and a plurality of mesh holes 213 penetrating the non-contact surface 211 and the contact surface 212, the first mesh layer The bottom surface of 21 refers to the contact surface 212 of the first mesh layer 21. The first barrier layer 22 defines a plurality of first openings 221 corresponding to the through holes 115 and a plurality of second openings 222 corresponding to the non-light-receiving surface 113 respectively, and the second barrier layer 23 defines a plurality of corresponding The third opening 231 such as the first opening 221 is used for making the conductive paste (not shown in the figure) of the first electrode 131 and the second electrode 132 can only pass through the first mesh layer 21 The first openings 221, the second openings 222, and the third openings 231 flow to the substrate 11 (see FIG. 3), that is, the first openings 221, the second openings 222, and the The third opening 231 is used to define the patterns of the first electrodes 131 and the second electrodes 132. In addition, by the arrangement of the second barrier layers 23, the first barrier layer 22 and the second barrier layer 23 used to block the conductive paste can be formed into structures with different thicknesses, so that the first electrodes 131 Compared with the non-light-receiving surface 113, the second electrodes 132 have a predetermined height drop.

In step S021, after the first screen structure 2 and the solar cell semi-finished product are completely aligned, a conductive paste (for example, silver paste) may be coated on the first mesh layer 21, and then the screen is printed The scraper structure (not shown in the figure) used in the procedure presses the first mesh layer 21 corresponding to the second barrier layer 23, so that the second barrier layer 23 is pressed against the non-light-receiving surface 113 and adjacent to the perforation 115 (See FIG. 13), and the conductive paste used to make the first electrodes 131 is coated through the mesh holes 213, the first openings 221, and the third openings 231 of the first screen structure 2. Inside the through holes 115, and filled to be flush with the non-contact surface 211 of the first mesh layer 21, and the other end of each first electrode 131 is completely covered and fixed to the second semiconductor layer 112 toward the through hole 115 One side is substantially flush with the light-receiving surface 114. As the scraper structure moves to correspond to the second openings 222, the end of the first barrier layer 22 without the second barrier layer 23 is pressed against the non-light-receiving surface 113 and away from the through hole 115 (as shown in FIG. 14) At this time, the conductive paste is respectively coated on the non-light-receiving surface 113 through the second openings 222 of the first screen structure 2 and filled to be flush with the non-contact surface 211 of the first mesh layer 21 The second electrode 132 is made into a flat structure. Accordingly, according to the provision of the second barrier layers 23 under the first barrier layer 22 where the first electrodes 131 are to be fabricated, the first screen structure 2 can form a thickness difference during the same screen printing process The arrangement of the first electrode 131 and the second electrode 132 of FIG. 1 is as shown in FIG. 1. In particular, in a preferred embodiment, the end surface of the first electrode 131 reaches the corresponding second electrode The end face difference of 132 is greater than 5 microns.

Referring to FIGS. 15 and 16, step S022 is next performed. In this step S022, the second screen structure 3 is used to perform a screen printing process to screen-print the conductive layer 133 on the non-light-receiving surface 113 and the second electrodes 132 On top, the conductive layer 133 covers the non-light-receiving surface 114 and overlaps a portion of each second electrode 132. Further, the second screen structure 3 includes a second mesh layer 31 and a third barrier layer 32 fixed to the bottom surface of the second mesh layer 31. The structure of the second mesh layer 31 is similar to that of the first mesh layer 21, so it will not be described in detail. In addition, the third barrier layer 32 defines a pair of fourth openings 321 that should be non-light-receiving surfaces 113. The difference between the second screen structure 3 and the first screen structure 2 is that the second screen structure 3 has only a third barrier layer 32 with a uniform thickness, so it cannot be fabricated like the first screen structure 2 Structures with different thicknesses. In step S022, when the doctor blade structure presses around the corresponding second electrodes 132 of the second mesh layer 31, the third barrier layer 32 presses against and shields the first electrodes 131, and the first A part of the two electrodes 132, at this time, the conductive paste (for example, aluminum paste) used to make the conductive layer 133 is coated on the non-light-receiving surface 113 through the fourth opening 321 of the second screen structure 3 without being affected by the first The portion shielded by the three barrier layers 32, and the conductive layer 133 partially overlaps each second electrode 132, and is not in contact with the first electrodes 131, that is, is not electrically connected to the first electrodes 131. Forming an electric field through the conductive layer 133 can effectively prevent the separated hole carriers from recombining with the electron carriers again.

Referring to FIGS. 3 and 12, it is particularly important to note that the first mesh layer 21 has a first thickness L1, and the contact surface 212 of the first mesh layer 21 to the bottom surface of the first barrier layer 22 has a first Two thicknesses L2 and the second barrier layer 23 have a third thickness L3, and the distance from the end surface of each first electrode 131 to the non-light-receiving surface 113 is substantially equal to the first thickness L1, the second thickness L2 and the first thickness The sum of three thicknesses L3. Compared to the second electrode 132, the thickness of each second electrode 132 is substantially equal to the sum of the second thickness L2 and the third thickness L3. Therefore, the thickness of the overlap between the conductive layer 133 and the second electrode 132 is substantially equal to the sum of the first thickness L1, the second thickness L2, and the third thickness L3. That is, in step S021, the distance from the end surface of the first electrode 131 to the non-light-receiving surface 113 is greater than the thickness of the second electrode 132, whereby in step S022, the conductive layer 133 and the second electrode 132 The thickness at the overlap is substantially equal to the distance from the end surface of the first electrode 131 to the non-light-receiving surface 113.

In this embodiment, substantially equal means that the end surface of each first electrode 131 is the same height as the end surface of the corresponding second electrode 132 overlapping the conductive layer 133, but the end surface of the first electrode 131 may also be lower than The end face at the aforementioned overlap, or the end face of the first electrode 131 is higher than the end face at the aforementioned overlap, it should be explained here that even if there is a difference in height between the end faces, in a preferred embodiment, each first The difference between the end surface of the electrode 131 and the end surface where the corresponding second electrode 132 overlaps with the conductive layer 133 is less than 15 microns, and the two end surfaces are nearly equal in height, which can reduce the structural wear caused by the transportation process.

Referring to FIGS. 4 and 5, finally, step S03 is performed. In this step S03, the conductive unit 13 is sintered at a high temperature to solidify and shape the conductive unit 13, and the production of the solar cell 1 is completed.

In addition, the above-mentioned first screen structure 2 and the second screen structure 3 can also be used to print the positive and negative electrodes of an interdigitated back contact solar cell (IBC). The heights are approximately equal, thereby avoiding damage to the electrodes due to friction during the stacking process.

In summary, the solar cell 1 of the present invention prints the first electrodes 131 and the second electrodes 132 with different thicknesses on the substrate 11 by screen printing, and controls the first electrodes 131 and the second electrodes by controlling The thickness of 132 allows the thickness of the overlap between the conductive layer 133 and the second electrode 132 of the second screen printing to be equal to the distance from the end surface of the first electrode 131 to the non-light-receiving surface 113. Therefore, the solar cells 1 During the transportation process in the upper and lower stacking mode, the stacked solar cells 1 can avoid the situation of mutual friction due to vibration, thereby improving the production yield. Therefore, the purpose of cost invention can indeed be achieved.

However, the above are only examples of the present invention, and should not be used to limit the scope of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the patent specification are still classified as This invention covers the patent.

1‧‧‧Solar cell 11‧‧‧Substrate 111‧‧‧First semiconductor layer 112‧‧‧Second semiconductor layer 113‧‧‧ Non-light-receiving surface 114‧‧‧Receiving surface 115‧‧‧Perforation 116‧‧‧Products Layer 12‧‧‧Anti-reflective layer 13‧‧‧Conducting unit 131‧‧‧ First electrode 132‧‧‧Second electrode 133‧‧‧Conducting layer 14‧‧‧Insulating layer 15‧‧‧Conducting layer 2‧‧‧ First screen structure 21‧‧‧ First mesh layer 211‧‧‧ Non-contact surface 212‧‧‧ Contact surface 213‧‧‧ Mesh 22‧‧‧ First barrier layer 221‧‧‧ First opening 222‧ ‧‧Second opening 23‧‧‧Second barrier layer 231‧‧‧ Third opening 3‧‧‧Second screen structure 31‧‧‧Second mesh layer 32‧‧‧ Third barrier layer 321‧‧‧‧ Fourth opening L1‧‧‧ First thickness L2‧‧‧Second thickness L3‧‧‧ Third thickness A‧‧‧End face of the first electrode B‧‧‧The overlap between the conductive layer and the second electrode S01~S03‧‧‧ Step flow S011~S015‧‧‧Step flow S021~S023‧‧‧Step flow

Other features and effects of the present invention will be clearly presented in the embodiment with reference to the drawings, in which: FIG. 1 is a schematic bottom view of an embodiment of the solar cell of the present invention; FIG. 2 is a schematic top view of the embodiment FIG. 3 is a schematic side view of one of the embodiments, illustrating the detailed structure of the solar cell; FIG. 4 is a flowchart of one step of this embodiment; FIG. 5 is a flowchart of one step of this embodiment; FIGS. 6 to 11 Is a schematic flow chart of this embodiment, illustrating the steps of providing a semi-finished solar cell; and FIGS. 12 to 16 are schematic flow charts of this embodiment, illustrating the steps of fabricating a conductive unit on the semi-finished solar cell.

1‧‧‧solar battery

11‧‧‧ substrate

111‧‧‧First semiconductor layer

112‧‧‧Second semiconductor layer

113‧‧‧non-light-receiving surface

114‧‧‧Receiving surface

115‧‧‧Perforation

12‧‧‧Anti-reflection layer

13‧‧‧Conducting unit

131‧‧‧First electrode

132‧‧‧Second electrode

133‧‧‧ conductive layer

14‧‧‧Insulation

15‧‧‧conductive layer

A‧‧‧End face of the first electrode

B‧‧‧The overlap between the conductive layer and the second electrode

Claims (10)

A method for manufacturing a solar cell includes the following steps: (A) providing a semi-finished solar cell product including a substrate and an anti-reflection layer, the substrate having a light-receiving surface and a non-light-receiving surface on opposite sides, and Forming a plurality of spaced-apart through-holes through the light-receiving surface and the non-light-receiving surface, the anti-reflection layer is disposed on the light-receiving surface; and (B) a conductive unit is fabricated on the semi-finished solar cell, the conductive unit includes a plurality of The perforated first electrodes, a plurality of second electrodes provided on the non-light-receiving surface of the substrate, and a conductive layer provided on the non-light-receiving surface of the substrate, the first electrodes protruding out of the non-light-receiving surface And a portion of each second electrode overlaps with the conductive layer, and the distance from the end surface of the first electrode protruding from the non-light-receiving surface to the non-light-receiving surface is substantially equal to the thickness of the overlapping portion of the second electrode and the conductive layer. The method for manufacturing a solar cell according to claim 1, wherein the step (B) includes a step (B1), in which the first electrodes and the For the second electrode, the thickness of the second electrode is smaller than the distance from the end surface of the first electrode protruding from the non-light-receiving surface to the non-light-receiving surface. The method for manufacturing a solar cell according to claim 2, wherein the step (B) further includes a step (B2) after the step (B1), in which another screen printing is performed in the step (B2) The program screen prints the conductive layer on the non-light-receiving surface and the second electrodes, so that the conductive layer covers the non-light-receiving surface and overlaps a portion of each second electrode. The method for manufacturing a solar cell according to claim 3, wherein in step (A), a first screen structure is further provided, and the first screen structure includes a first mesh layer and a first screen structure A first barrier layer on the bottom surface of the mesh layer, and a plurality of second barrier layers spaced on the bottom surface of the first barrier layer, the first barrier layer defines a plurality of first openings corresponding to the perforations and A plurality of second openings corresponding to the non-light-receiving surface, the second barrier layer defines a plurality of third openings respectively corresponding to the first openings, and the first mesh layer has a first thickness, the first mesh The bottom surface of the cloth layer to the bottom surface of the first barrier layer has a second thickness, and the second barrier layer has a third thickness. In step (B1), the second barrier layer is pressed against the non-light-receiving surface and is adjacent to The through hole, and one end of the first barrier layer away from the second barrier layer is pressed against the non-light-receiving surface and away from the through hole, so that the first electrodes pass through the first openings of the first screen structure and The third openings are coated on the perforations, and the second electrodes are simultaneously coated on the non-light-receiving surface through the second openings of the first screen structure, respectively, and the end surface of each first electrode reaches The distance of the non-light-receiving surface is equal to the sum of the first thickness, the second thickness, and the third thickness, and the thickness of each second electrode is equal to the sum of the second thickness and the third thickness. The method for manufacturing a solar cell according to claim 4, wherein in step (A), a second screen structure is further provided, and the second screen structure includes a second mesh layer and a second screen structure fixed to the second A third barrier layer of the mesh layer, the third barrier layer defines a fourth opening, and in step (B2), the third barrier layer is laminated to shield the first electrodes and part of the second electrodes The conductive layer is applied to the portion of the non-light-receiving surface that is not shielded by the third barrier layer through the fourth opening of the second screen structure, and the conductive layer partially overlaps with each second electrode, and the The thickness of the overlap between the conductive layer and the second electrode is equal to the sum of the first thickness, the second thickness, and the third thickness. The method for manufacturing a solar cell according to claim 5, wherein the height of each first electrode is higher than the height of the corresponding second electrode, and the end surface of the first electrode is different from the end surface of the corresponding second electrode Greater than 5 microns. The method for manufacturing a solar cell according to claim 5, wherein in step (B2), the difference between the end surface of each first electrode and the end surface where the corresponding second electrode overlaps the conductive layer is less than 15 microns. A solar cell includes: a substrate including a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer and having a plurality of carriers different from the first semiconductor layer, the first semiconductor layer having a non- A light-receiving surface, and the second semiconductor layer has a light-receiving surface opposite to the non-light-receiving surface, the substrate forms a plurality of spaced-apart through-holes that penetrate the light-receiving surface and the non-light-receiving surface; an anti-reflection layer is prepared on the light-receiving surface; A conductive unit, including a plurality of first electrodes respectively provided on the perforations, a plurality of second electrodes provided on the non-light-receiving surface of the substrate, and a conductive layer provided on the non-light-receiving surface of the substrate, the first An electrode protrudes out of the non-light-receiving surface, and a portion of each second electrode overlaps with the conductive layer. The distance from the end surface of the first electrodes protruding from the non-light-receiving surface to the non-light-receiving surface is substantially equal to the second electrode and The thickness of the overlapping portion of the conductive layer; and an insulating layer disposed in the through holes and bounded between the substrate and the first electrodes to electrically insulate the first electrode from the first semiconductor layer. The solar cell of claim 8, wherein the height of each first electrode is higher than the height of the corresponding second electrode, and the difference between the end surface of the first electrode and the end surface of the corresponding second electrode is greater than 5 microns . The solar cell according to claim 8, wherein the difference between the end surface of each first electrode and the end surface where the corresponding second electrode overlaps the conductive layer is less than 15 microns.

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