CN116995131A

CN116995131A - Solar cell preparation method, solar cell and cell assembly

Info

Publication number: CN116995131A
Application number: CN202310834031.6A
Authority: CN
Inventors: 薛朝伟; 魏超锋; 李�杰; 孙士洋; 方亮; 魏俊喆; 曲铭浩; 徐希翔
Original assignee: Longi Green Energy Technology Co Ltd
Current assignee: Longi Green Energy Technology Co Ltd
Priority date: 2022-07-07
Filing date: 2023-07-07
Publication date: 2023-11-03
Also published as: CN115241323A

Abstract

The application provides a solar cell preparation method, a solar cell and a cell assembly, and relates to the technical field of photovoltaics. The method comprises the following steps: forming a first conductive pattern or a first conductive film layer on the solar cell body; forming a second conductive pattern on the imprint template; aligning the second conductive pattern with the first conductive pattern and eutectic bonding the second conductive pattern with the first conductive pattern; or aligning the second conductive pattern with the region of the first conductive film layer where the electrode is to be formed, and eutectic bonding the second conductive pattern and the region of the first conductive film layer where the electrode is to be formed; the imprint template is removed. The second conductive pattern is prepared on the imprinting template, so that the influence on the solar cell body can be reduced, mass production is easy to realize, the process is simple and mature, and the preparation cost can be reduced.

Description

Solar cell preparation method, solar cell and cell assembly

The present application claims priority from the chinese patent office, application number 202210795204.3, entitled "solar cell fabrication method, solar cell and cell module," filed 7/2022, the entire contents of which are incorporated herein by reference.

Technical Field

The invention relates to the technical field of photovoltaics, in particular to a solar cell preparation method, a solar cell and a cell assembly.

Background

In general, there are mainly the following three requirements for the electrodes of solar cells: higher carrier collection efficiency, lower preparation cost and good reliability.

However, in the prior art, the electrode preparation methods of the solar cell mainly include the following three methods: first, screen printing is mature in screen printing process, however, in screen printing, noble metal silver is required to be used as an electrode material, so that the cost is high. And secondly, laser transfer printing, namely, after forming silver paste on the transparent film layer and drying, irradiating a local area of the transparent film layer by using laser, separating the silver paste of the irradiated part from the transparent film layer, and falling on an area of the solar cell body where an electrode is to be formed to form the electrode. In laser transfer printing, the light-transmitting film layer cannot be reused, and silver paste remains on the light-transmitting film layer, so that the cost of laser transfer printing is still high; meanwhile, the matching difficulty of the light-transmitting film layer and the laser process is high, for example, in the matching process of the light-transmitting film layer and the laser process, as silver paste with different proportions is different in solvent evaporation capacity, adhesive force between the paste and a carrier plate and the like, the parameters of laser are required to be adjusted for multiple times to adapt to the silver paste, so that the silver paste and the laser power can be matched well, and therefore, the laser transfer printing process is high in difficulty and low in production efficiency. Thirdly, electroplating has advantages in efficiency and cost compared with screen printing and laser transfer printing, but electroplating is easy to have the technical problems of coiling plating and the like, so that the yield and reliability are low, and mass production is not easy to realize.

Disclosure of Invention

The invention provides a solar cell preparation method, a solar cell and a cell assembly, and aims to solve the problem of high preparation cost of an electrode of the solar cell.

In a first aspect of the present invention, there is provided a method for manufacturing a solar cell, comprising:

forming a first conductive pattern or a first conductive film layer on the solar cell body;

forming a second conductive pattern on the imprint template;

aligning the second conductive pattern with the first conductive pattern and eutectic bonding the second conductive pattern with the first conductive pattern; or aligning the second conductive pattern with the region of the first conductive film layer where the electrode is to be formed, and eutectic bonding the second conductive pattern and the region of the first conductive film layer where the electrode is to be formed;

removing the imprinting template;

the method further comprises the steps of forming a first conductive film layer on the solar cell body, and after removing the imprinting template, removing the first conductive film layer: and removing the part of the first conductive film layer except the region where the electrode is to be formed, so as to form a first conductive pattern.

In the present invention, the second conductive pattern is prepared on the imprint template, not on the solar cell body, and the preparation process of the second conductive pattern has little or no influence on the solar cell body. Meanwhile, the eutectic bonding has the characteristics of low bonding temperature and high bonding strength, and the low bonding temperature can enable the solar cell body to be less affected by heat and has little influence on the photoelectric conversion efficiency of the solar cell. The high bonding strength can make the reliability of the electrode of the solar cell good. The second conductive pattern, the first conductive film layer, or the first conductive pattern of the present invention may be formed of a material that can be eutectic bonded with respect to screen printing, and is not limited to silver paste, so that the cost can be suitably reduced. Compared with laser transfer printing, the invention has the advantages that the second conductive pattern and the first conductive pattern are bonded together in an eutectic way, or the second conductive pattern and the region to be formed with the electrode in the first conductive film layer are bonded together in an eutectic way, the eutectic bonding process is mature, and the parameters of laser and the like do not need to be adjusted for multiple times, so that the process difficulty is relatively low, and the production efficiency can be properly improved. Compared with electroplating, the invention has the advantages that the second conductive pattern and the first conductive pattern are bonded together in an eutectic way, or the second conductive pattern and the region to be formed with the electrode in the first conductive film layer are bonded together in an eutectic way, so that the solar cell body has no technical problems of coiling and plating and the like, the yield and the reliability are good, and the mass production is easy to realize.

Optionally, before eutectic bonding, the method further comprises: annealing the imprint template formed with the second conductive pattern such that the second conductive pattern is recrystallized.

Optionally, before eutectic bonding, the method further comprises: forming a control diffusion pattern on the first conductive pattern or a region of the first conductive film layer where an electrode is to be formed; and/or forming a control diffusion pattern on the second conductive pattern;

wherein the diffusion control pattern is used for controlling the thickness of an alloy formed in eutectic bonding of the material of the first conductive film layer or the material of the first conductive pattern and the material of the second conductive pattern.

Optionally, before the forming of the first conductive pattern or the first conductive film layer on the solar cell body, the method further includes:

forming an adhesive pattern or an adhesive film layer on the solar cell body; the bonding pattern or the bonding film layer is used for improving the bonding force between the first conductive pattern or the first conductive film layer and the solar cell body;

the forming a first conductive pattern or a first conductive film layer on a solar cell body includes:

Forming the first conductive pattern or the first conductive film layer on the adhesive pattern or the adhesive film layer;

the method further comprises the steps of forming an adhesive film layer on the solar cell body, and after the imprinting template is removed, removing the adhesive film layer: and removing the part of the bonding film layer except the region where the electrode is to be formed, and forming the bonding pattern. Optionally, the imprint template includes a first groove; the forming of the second conductive pattern on the imprint template includes: forming the second conductive pattern in the first groove of the imprinting template;

the second conductive pattern is flush with the surface of the side, provided with the first groove, of the imprinting template, or protrudes out of the surface of the side, provided with the first groove, of the imprinting template.

Optionally, the imprinting template includes a substrate, the first groove is disposed on the substrate, and the imprinting template further includes a first boss disposed on the substrate and located at an edge of the first groove; the forming the second conductive pattern in the first groove of the imprint template includes:

forming the second conductive pattern in the first groove and in the area defined by the first boss;

The second conductive pattern is flush with the surface of the first boss away from the substrate, or protrudes from the surface of the first boss away from the substrate.

Optionally, the area of the cross section of the first groove gradually decreases along the direction from the notch of the first groove to the bottom of the groove; wherein the cross section is perpendicular to a lamination direction of the first conductive pattern and the second conductive pattern.

Optionally, the imprinting template comprises a substrate and a second boss positioned on the substrate;

the forming of the second conductive pattern on the imprint template includes:

and forming a second conductive film layer on one side of the imprinting template, on which the second boss is formed, wherein the second conductive pattern is a part of the second conductive film layer, which is positioned on the second boss.

Optionally, a surface of the second boss away from the substrate is a plane; or, the side of the second boss away from the substrate comprises a second groove, wherein the second conductive pattern is flush with the notch of the second groove or protrudes out of the second groove.

Optionally, the forming a second conductive pattern on the imprint template includes:

Forming a seed pattern on the imprint template;

plating or electroless plating is used to form a plating pattern on the seed pattern, and the plating pattern and the seed pattern together form the second conductive pattern.

Optionally, the imprint template includes a substrate, and the forming the second conductive pattern on the imprint template includes:

and paving a metal foil on the substrate, and patterning the metal foil to form the second conductive pattern.

Optionally, before the forming of the second conductive pattern on the imprint template, the method further includes:

providing a plurality of metal foil patterns;

the imprinting template comprises a plurality of adsorption areas; the forming of the second conductive pattern on the imprint template includes: at least one of the suction areas and one of the metal foil patterns are aligned, and the metal foil pattern is sucked on the suction area to form the second conductive pattern.

In a second aspect of the present invention, there is provided a solar cell comprising:

a solar cell body;

and a first conductive pattern and a second conductive pattern stacked on the solar cell body;

wherein the second conductive pattern and the first conductive pattern are connected together by eutectic bonding.

Optionally, the first conductive pattern is close to the solar cell body relative to the second conductive pattern;

the area of the cross section of the second conductive pattern or a partial area of the second conductive pattern away from the solar cell body is gradually reduced along the direction away from the solar cell body; wherein the cross section is perpendicular to a lamination direction of the first conductive pattern and the second conductive pattern.

Optionally, the shape of the second conductive pattern or the longitudinal section of the partial area of the second conductive pattern, which is far away from the solar cell body, is triangle, trapezoid, or a graph formed by a section of arc and a line segment connecting two endpoints of the arc, and the length of the line segment is smaller than or equal to the diameter of a circle corresponding to the arc; wherein the longitudinal section is parallel to a lamination direction of the first conductive pattern and the second conductive pattern.

Optionally, the solar cell further includes: and the bonding pattern is arranged between the first conductive pattern and the solar cell body and is used for improving the bonding force between the first conductive pattern and the solar cell body.

Optionally, the solar cell further includes: and a control diffusion pattern disposed between the first conductive pattern and the second conductive pattern, the control diffusion pattern being used to control a thickness of an alloy formed in eutectic bonding of the second conductive pattern and the first conductive pattern.

Optionally, in the stacking direction of the first conductive pattern and the second conductive pattern, the second conductive pattern is composed of at least two layers of second conductive sub-patterns stacked.

Optionally, in the stacking direction of the solar cell body and the first conductive pattern, the second conductive pattern includes a seed layer pattern and a plating pattern that are stacked; the plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern.

In a third aspect of the present invention, there is provided another method for manufacturing a solar cell, comprising:

forming a second conductive pattern on the imprint template;

aligning the second conductive pattern with a region of the solar cell body where an electrode is to be formed, and eutectic bonding the second conductive pattern to the region of the solar cell body where the electrode is to be formed;

And removing the imprinting template.

Optionally, before eutectic bonding, the method further comprises: forming a control diffusion pattern on the second conductive pattern and/or forming a control diffusion pattern on a region of the solar cell body where an electrode is to be formed;

wherein the control diffusion pattern is used for controlling the thickness of an alloy formed in eutectic bonding of the second conductive pattern and a region of the solar cell body where an electrode is to be formed.

Optionally, the imprint template includes a first groove; the forming of the second conductive pattern on the imprint template includes: forming the second conductive pattern in the first groove of the imprinting template;

Optionally, the area of the cross section of the first groove gradually decreases along the direction from the notch of the first groove to the bottom of the groove; wherein the cross section is perpendicular to a lamination direction of the second conductive pattern and the solar cell body.

the forming of the second conductive pattern on the imprint template includes:

forming a seed pattern on the imprint template;

providing a plurality of metal foil patterns;

Optionally, the material of the second conductive pattern is aluminum, and the second conductive pattern is in contact with the silicon substrate in the solar cell body;

the eutectic bonding of the second conductive pattern to the region of the solar cell body where the electrode is to be formed includes:

And in the process of eutectic bonding of the second conductive pattern in the region of the solar cell body where the electrode is to be formed, part of aluminum in the second conductive pattern is diffused into the region of the silicon substrate where the electrode is to be formed, so that the region of the silicon substrate where the electrode is to be formed is doped to form a P-type doped region, and the rest of the second conductive pattern is used as the electrode.

In a fourth aspect of the present invention, there is provided another solar cell comprising:

a solar cell body;

and a second conductive pattern disposed on the solar cell body;

wherein the second conductive pattern is eutectic bonded on the solar cell body.

Optionally, the area of the second conductive pattern or the cross section of a partial region of the second conductive pattern away from the solar cell body gradually decreases along a direction away from the solar cell body; wherein the cross section is perpendicular to a lamination direction of the second conductive pattern and the solar cell body.

Optionally, the shape of the second conductive pattern or the longitudinal section of the partial area of the second conductive pattern, which is far away from the solar cell body, is triangle, trapezoid, or a graph formed by a section of arc and a line segment connecting two endpoints of the arc, and the length of the line segment is smaller than or equal to the diameter of a circle corresponding to the arc; wherein the longitudinal section is parallel to a lamination direction of the second conductive pattern and the solar cell body.

Optionally, the solar cell further includes: and the control diffusion pattern is arranged between the second conductive pattern and the solar cell body and is used for controlling the thickness of an alloy formed in eutectic bonding of the second conductive pattern and the solar cell body.

Optionally, in the stacking direction of the solar cell body and the second conductive pattern, the second conductive pattern is composed of at least two layers of second conductive sub-patterns stacked.

Optionally, in a stacking direction of the solar cell body and the second conductive pattern, the second conductive pattern includes a seed layer pattern and a plating pattern that are stacked; the plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern.

In a fifth aspect of the present invention, there is provided a battery module including a first packaging film, a solar cell string, and a second packaging film laminated in this order; the solar cell string is formed by sequentially connecting a plurality of solar cells in series;

wherein the solar cell is any one of the solar cells described above.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments of the present invention will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural view of a battery assembly according to an exemplary embodiment of the present invention;

fig. 2 is a schematic structural diagram of a first HJT solar cell according to an exemplary embodiment of the present invention;

fig. 3 is a schematic structural diagram of an HBC solar cell according to an exemplary embodiment of the present invention;

fig. 4 is a schematic structural diagram of a second type HJT solar cell according to an exemplary embodiment of the present invention;

fig. 5 is a schematic structural diagram of a third HJT solar cell according to an exemplary embodiment of the present invention;

fig. 6 is a flowchart illustrating steps of a method for manufacturing a solar cell according to an embodiment of the present invention;

fig. 7 is a schematic view illustrating a partial structure of a first HJT solar cell according to an embodiment of the present invention;

fig. 8 is a schematic view illustrating a partial structure of a second type HJT solar cell according to an embodiment of the present invention;

Fig. 9 is a schematic diagram of a partial structure of a first HBC solar cell according to an embodiment of the present invention;

fig. 10 is a schematic diagram of a partial structure of a second HBC solar cell according to an embodiment of the present invention;

fig. 11 is a schematic view showing a partial structure of a first conductive pattern formed according to an exemplary embodiment of the present invention;

FIG. 12 is a schematic view showing a partial structure of a second conductive pattern formed according to an exemplary embodiment of the present invention;

fig. 13 is a schematic view showing a partial structure of a third embodiment of the present invention for forming a second conductive pattern;

fig. 14 is a schematic view showing a partial structure of a fourth embodiment of the present invention for forming a second conductive pattern;

fig. 15 is a schematic view showing a partial structure of a fifth embodiment of the present invention for forming a second conductive pattern;

fig. 16 is a schematic structural diagram illustrating alignment of a first second conductive pattern and a region of a first conductive film layer where an electrode is to be formed according to an exemplary embodiment of the present invention;

fig. 17 is a schematic structural diagram illustrating alignment of a second conductive pattern with a region of a first conductive film layer where an electrode is to be formed according to an exemplary embodiment of the present invention;

fig. 18 is a schematic structural diagram illustrating alignment of a third second conductive pattern with a region of a first conductive film layer where an electrode is to be formed according to an exemplary embodiment of the present invention;

Fig. 19 is a schematic view showing a partial structure of a third HJT solar cell according to an exemplary embodiment of the present invention;

fig. 20 is a schematic diagram of a partial structure of a third HBC solar cell according to an embodiment of the present invention;

FIG. 21 is a schematic structural view of a first imprint template according to an exemplary embodiment of the present invention;

FIG. 22 is a schematic structural view of a second imprint template according to an exemplary embodiment of the present invention;

FIG. 23 is a schematic structural view of a third imprint template according to an exemplary embodiment of the present invention;

FIG. 24 is a schematic structural view of a fourth imprint template according to an exemplary embodiment of the present invention;

fig. 25 is a schematic structural view of a fourth HJT solar cell according to an exemplary embodiment of the present invention;

FIG. 26 is a schematic structural view of a fifth imprint template according to an exemplary embodiment of the present invention;

fig. 27 is a schematic view showing a partial structure of a sixth embodiment of the present invention for forming a second conductive pattern;

fig. 28 is a schematic view of a seventh partial structure for forming a second conductive pattern according to an exemplary embodiment of the present invention;

fig. 29 is a flowchart illustrating steps of another method for manufacturing a solar cell according to an embodiment of the present invention;

Fig. 30 is a schematic view illustrating a partial structure of a solar cell according to an embodiment of the present invention.

Reference numerals:

1-solar cell string, 2-first encapsulation film, 3-second encapsulation film, 4-transparent cover plate, 5-back plate, 101-substrate, 102-first boss, 103-first recess, 104-second conductive film layer, second conductive pattern, 1041, 1042, 1043-second conductive sub-pattern, 1044-metal wire, 1045-coating, 1046-aluminum paste sub-pattern, 1047-seed pattern, 1048-plating pattern, 202-second boss, 2021-second recess, 311-bonding layer, bonding pattern, 321-first conductive film layer, first conductive pattern, 301-front TCO film, 302-N type hydrogen doped amorphous silicon/microcrystalline silicon oxide passivation layer, 303-front intrinsic amorphous silicon passivation layer, 304-front intrinsic amorphous silicon buffer layer, 305-silicon substrate, 306-back intrinsic amorphous silicon buffer layer, 307-back intrinsic amorphous silicon passivation layer, 308-P type amorphous silicon emitter, 309-back TCO film, 401-back TCO layer, 402-front side nitride layer, 403-N type layer, 405-P type bulk layer, 305-i type bulk layer, and 409-back side region.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Fig. 1 is a schematic structural view of a battery assembly according to an exemplary embodiment of the present invention. The embodiment of the invention provides a battery assembly, as shown in fig. 1, the battery assembly comprises a first packaging adhesive film 2, a solar cell string 1 and a second packaging adhesive film 3 which are sequentially stacked, wherein the solar cell string 1 comprises a plurality of solar cells which are sequentially connected in series. In some examples, the first and second encapsulation films 1 and 3 may be EVA (ethylene-vinyl acetate copolymer ) films.

Referring to fig. 1, in some examples, the battery assembly may further include: the transparent cover plate 4 is arranged on one side of the first packaging adhesive film 2 far away from the solar cell string 1; and/or a back plate 5 arranged on the side of the second packaging adhesive film 3 far away from the solar cell strings 1.

The embodiment of the invention also provides a solar cell which can be applied to the cell assembly, in particular to a solar cell which is applied to the solar cell string. The present invention is not limited to the type of solar cell, and the solar cell may be, for example, HJT (heteroo-Junction with Intrinsic Thin-layer, heterojunction) solar cell, SHJ (Silicon Heterojunction solar cells, silicon heterojunction solar cell), IBC (Interdigited back contact, interdigital back contact) solar cell, TOPcon (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact) solar cell, PERC (Passivated Emitterand Rear Cell, passivation emitter and back side solar cell), or the like.

Fig. 2 is a schematic structural diagram of a first HJT solar cell according to an exemplary embodiment of the present invention. Fig. 3 is a schematic structural diagram of an HBC solar cell according to an exemplary embodiment of the present invention. Fig. 4 is a schematic structural diagram of a second HJT solar cell according to an exemplary embodiment of the present invention. Fig. 5 is a schematic structural diagram of a third HJT solar cell according to an exemplary embodiment of the present invention.

As shown in fig. 2, 3, 4, and 5, the solar cell includes a solar cell body, and positive and negative electrodes provided on the solar cell body. Based on this, it is understood that in the solar cell, the other portions than the positive electrode and the negative electrode may be regarded as the solar cell body. The structure of the solar cell body is different for different types of solar cells, and is described below by way of two examples.

In the case of HJT solar cell, as shown in fig. 2, 4 and 5, the HJT solar cell may include, for example, a front TCO (Transparent conducting oxide, transparent conductive oxide film) 301, an N-type hydrogen doped amorphous silicon/microcrystalline silicon oxide passivation layer 302, a front intrinsic amorphous silicon passivation layer 303, a front intrinsic amorphous silicon buffer layer 304, a silicon substrate 305, a back intrinsic amorphous silicon buffer layer 306, a back intrinsic amorphous silicon passivation layer 307, a P-type amorphous silicon emitter 308, a back TCO309, and a negative electrode disposed on the front TCO301 and a positive electrode disposed on the back TCO309, which are stacked in this order. Among them, the front TCO301, the N-type hydrogen-doped amorphous silicon/microcrystalline silicon oxide passivation layer 302, the front intrinsic amorphous silicon passivation layer 303, the front intrinsic amorphous silicon buffer layer 304, the silicon substrate 305, the back intrinsic amorphous silicon buffer layer 306, the back intrinsic amorphous silicon passivation layer 307, the P-type amorphous silicon emitter 308, and the back TCO309, which are stacked in this order, can be considered as a solar cell body of the HJT solar cell.

In example two, in the case where the above-described solar cell is an HBC (Heterojunction back contact ) solar cell, as shown in fig. 3, the HBC solar cell may include, for example, a front side silicon nitride layer 401, a front side n layer 402, a front side i layer 403, a silicon substrate 305, a back side i layer 405, an n-type layer 406, a p-type layer 408, a spacer 409, a back side TCO309, and a positive electrode disposed on the p-type layer 408 and a negative electrode disposed on the n-type layer 406. Among these, the front side silicon nitride layer 401, the front side n layer 402, the front side i layer 403, the silicon substrate 305, the back side i layer 405, the n-type layer 406, the p-type layer 408, the spacer 409, and the back side TCO309 can be considered as the solar cell body of the HBC solar cell.

In the solar cell, the positive electrode and the negative electrode may be located on the same side of the solar cell body, or may be disposed on opposite sides of the solar cell body, respectively.

Several examples are provided below to describe the structure and fabrication method of solar cells.

Example 1

A first embodiment provides a solar cell, referring to fig. 2, 3, 4, and 5, the solar cell includes a solar cell body, and a positive electrode and a negative electrode disposed on the solar cell body; the structure of the positive electrode and the structure of the negative electrode may be the same or different. The electrode (which may be a positive electrode or a negative electrode) of the solar cell includes: the first conductive pattern 321 and the second conductive pattern 104 formed on the solar cell body are stacked; wherein the first conductive pattern 321 and the second conductive pattern 104 are connected together by eutectic bonding. Eutectic bonding here refers to: at a certain temperature and pressure, the first conductive pattern 321 and the second conductive pattern 104 are diffusion alloyed with each other at the interface where they are in contact. The temperature required for eutectic bonding is generally required to match the metal materials in the first conductive pattern 321 and the second conductive pattern 104, and in general, the temperature required for eutectic bonding between different metal materials may be different, which is not particularly limited in the present invention. Alternatively, the pressure of the eutectic bonding may be 100-1000N (newton), which not only can achieve good and firm bonding between the first conductive pattern 321 or the first conductive film layer 321 and the second conductive pattern 104, but also has relatively small stress conducted to the solar cell body, and has less influence on the solar cell body. For example, the pressure of the eutectic bonding may be 100N, 200N, 500N, 600N, 800N, 1000N, etc.

For example, for a double sided cell, the electrodes may be located on the light facing side or the backlight side of the solar cell body. For a back contact solar cell, the electrode may be located on the backlight side of the solar cell body. It is understood that the portion of the solar cell body in contact with the first conductive pattern can be electrically conductive, for example, the portion of the solar cell body in contact with the first conductive pattern can be TCO; or the portion of the solar cell body in contact with the first conductive pattern may be a doped layer. For another example, if a passivation layer is formed on the surface of the solar cell body, the portion of the solar cell body that contacts the first conductive pattern is a layer that is exposed after the passivation layer is grooved.

The first conductive pattern 321 and the second conductive pattern 104 are eutectic bonded together, and the eutectic bonding process is simple and mature and is easy to realize mass production. Meanwhile, the eutectic bonding has the characteristics of low bonding temperature and high bonding strength, and the low bonding temperature can enable the solar cell body to be less affected by heat and has little influence on the photoelectric conversion efficiency of the solar cell. The high bonding strength can make the reliability of the electrode of the solar cell good. In the eutectic bonding, the materials of the second conductive pattern 104 and the first conductive pattern 321 can be eutectic bonded, and are not limited to silver paste, the material selectivity is high, and compared with silver paste, copper, tin and the like can be selected, for example, so that the cost can be properly reduced. In addition, since the second conductive pattern 104 may not be prepared on the solar cell body, the preparation process of the second conductive pattern has little or no effect on the solar cell body, and mass production is easy to achieve, and the preparation cost may be reduced.

The material of the first conductive pattern 321 and the second conductive pattern 104 may be a material capable of eutectic bonding, and the material of the first conductive pattern 321 or the first conductive film layer 321 and the second conductive pattern 104 is not particularly limited. For example, the first conductive pattern 321 or the first conductive film layer 321, the second conductive pattern 104 may be selected from: the material with the temperature of the eutectic bonding being less than or equal to 400 ℃ can reduce the thermal influence of the eutectic bonding on the solar cell body. For another example, the first conductive pattern 321 or the first conductive film layer 321, the second conductive pattern 104 may be selected from: a material having a eutectic bonding temperature of less than or equal to 200 ℃.

It should be noted that the difference between fig. 2 and fig. 3 is mainly that the structure of the solar cell body is different, and the shape of the second conductive pattern 104 is different. Fig. 2 and 4 differ mainly in the shape of the second conductive pattern 104.

Alternatively, the first conductive pattern 321 and the second conductive pattern 104 may be made of a low-temperature conductive material, so that the thermal influence of eutectic bonding on the solar cell body can be reduced. The first conductive pattern 321 and the second conductive pattern 104 may be at least one of the following eight low-temperature conductive materials: the melting point of the first low-temperature conductive material is 98 ℃, and the composition components are as follows: bismuth (Bi) in a mass ratio of 50%, lead (Pb) in a mass ratio of 25%, and tin (Sn) in a mass ratio of 25%. The second low-temperature conductive material has a melting point of 74 ℃ and comprises the following components: 42.5% bismuth (Bi), 37.7% lead (Pb), 11.3% tin (Sn), 8.5% cadmium (Cd). The third low-temperature conductive material has a melting point of 70 ℃ and comprises the following components: bismuth (Bi) in a mass ratio of 50%, lead (Pb) in a mass ratio of 26.7%, tin (Sn) in a mass ratio of 13.3%, and cadmium (Cd) in a mass ratio of 10%. The fourth low-temperature conductive material has a melting point of 62 ℃ and comprises the following components: 32.5% by mass of bismuth (Bi), 16.5% by mass of tin (Sn), and 51% by mass of indium (In). The melting point of the fifth low-temperature conductive material is 58 ℃, and the composition components are as follows: bismuth (Bi) In a mass ratio of 49%, lead (Pb) In a mass ratio of 18%, tin (Sn) In a mass ratio of 12%, and indium (In) In a mass ratio of 21%. The melting point of the sixth low-temperature conductive material is 47.2 ℃, and the composition components are as follows: bismuth (Bi) In a mass ratio of 44.7%, lead (Pb) In a mass ratio of 22.6%, tin (Sn) In a mass ratio of 8.3%, indium (In) In a mass ratio of 19.1%, and cadmium (Cd) In a mass ratio of 5.3%. The melting point of the seventh low-temperature conductive material is 41.5 ℃, and the composition components are as follows: bismuth (Bi) 40.3% by mass, lead (Pb) 22.2% by mass, tin (Sn) 10.7% by mass, indium (In) 17.7% by mass, cadmium (Cd) 8.1% by mass, thallium (TI) 1.1% by mass. The melting point of the eighth low-temperature conductive material is 30.0 ℃, and the composition components are as follows: gallium (Ga) in a mass ratio of 100%.

Alternatively, the first conductive pattern 321 or the material of the first conductive film layer 321 and the second conductive pattern 104 may be selected from one of the following pairs of materials, and the first conductive pattern 321 or the first conductive film layer 321 is selected from one of the following pairs of materials, and then the second conductive pattern 104 is selected from the other of the following pairs of materials. The material pair may include: copper (Cu), copper (Cu) material pairs, copper (Cu), tin (Sn) material pairs, gold (Au), indium (In) material pairs, gold (Au), germanium (Ge) material pairs. The material pair is easy to realize eutectic bonding at the temperature of less than or equal to 400 ℃, and the eutectic bonding is firmer. For example, copper (Cu) material pairs can achieve good eutectic bonding at temperatures of 150-200 ℃. Copper (Cu) and tin (Sn) materials can realize good eutectic bonding at the temperature of 231 ℃. Gold (Au) and indium (In) material pairs can realize good eutectic bonding at the temperature of 156 ℃. Gold (Au) and germanium (Ge) materials can realize good eutectic bonding at 361 ℃.

Alternatively, referring to fig. 2 to 5, the first conductive pattern 321 is adjacent to the solar cell body with respect to the second conductive pattern 104. In fig. 2, the direction indicated by the dashed arrow L1 is: in a direction away from the solar cell body. The area of the cross section of the partial region of the second conductive pattern 104 away from the solar cell body is gradually reduced in the direction away from the solar cell body, which is perpendicular to the lamination direction of the first conductive pattern 321 and the second conductive pattern 104, that is, the smaller the area of the cross section of the partial region of the second conductive pattern 104 away from the solar cell body is, the less reflection and light shielding are facilitated, and the photoelectric conversion efficiency of the solar cell can be increased.

Referring to fig. 2 and 5, in some examples, the second conductive pattern 104 includes a second conductive sub-pattern 1041 and a second conductive sub-pattern 1042 that are stacked, and the second conductive sub-pattern 1042 is close to the first conductive pattern 321 with respect to the second conductive sub-pattern 1041. The area of the cross section of the second conductive pattern 104 gradually decreases in a direction away from the solar cell body, having the effect of reducing reflection and shading. Alternatively, in a direction away from the solar cell body, the areas of the cross sections of the second conductive sub-pattern 1042 of the second conductive pattern 104, which is close to the first conductive pattern 321, are equal, the areas of the cross sections of the second conductive pattern 104, which is far away from the second conductive sub-pattern 1041 of the first conductive pattern 321, are gradually reduced, and the second conductive sub-pattern 1041 has the effect of reducing reflection and shading.

Optionally, the second conductive pattern 104 or a longitudinal section of a partial area of the second conductive pattern 104 away from the solar cell body has a triangular shape, a trapezoidal shape, or a pattern formed by a segment of an arc and a segment connecting two ends of the arc, the segment having a length less than or equal to a diameter of a circle corresponding to the arc, and the longitudinal section being parallel to a lamination direction of the first conductive pattern 321 and the second conductive pattern 104. If the length of the line segment is equal to the diameter of the circle corresponding to the circular arc, the shape of the longitudinal section of the second conductive pattern 104 or the partial region of the second conductive pattern 104 away from the solar cell body is a semicircle, and the shape of the second conductive pattern 104 or the partial region of the second conductive pattern 104 away from the solar cell body is a semicircle. If the length of the line segment is smaller than the diameter of the circle corresponding to the circular arc, the circular arc is a minor arc of the circle corresponding to the circular arc.

In fig. 2 and 5, the second conductive sub-pattern 1041 of the second conductive pattern 104 far from the solar cell body has a triangular shape, and the second conductive sub-pattern 1042 of the second conductive pattern 104 near to the solar cell body has a rectangular shape. The longitudinal section of the second conductive pattern 104 is formed by splicing a rectangle and a triangle, the bottom side of the triangle coincides with one side of the rectangle, and the opposite corner of the bottom side is positioned on one side of the second conductive pattern 104 away from the first conductive pattern 321.

Optionally, referring to fig. 2 to 4, the electrode of the solar cell further includes: the bonding pattern 311 between the first conductive pattern 321 and the solar cell body, the bonding pattern 311 is used to promote the bonding force between the first conductive pattern 321 and the solar cell body, so that the reliability of the electrode is better. The shape of the bonding pattern 311 may be the same as or similar to the shape of the first conductive pattern 321. The material of the bonding pattern 311 may be selected from: at least one of titanium, chromium, copper, nickel, lead, tin, titanium nitride, titanium tungsten and silver, the bonding pattern 311 of the material and the solar cell body have strong bonding force, and the bonding force between the first conductive pattern 321 and the solar cell body is indirectly improved. The adhesive pattern 311 may have a single-layer structure or a multi-layer structure, and as shown in fig. 2 to 5, the adhesive pattern 311 may have a single-layer structure.

Alternatively, the thickness of the bonding pattern 311 may be 1-50nm, which is parallel to the lamination direction of the first conductive pattern 321 and the second conductive pattern 104, and the thickness of the bonding pattern 311 is within this range, so that not only the improvement effect on the bonding force between the first conductive pattern 321 and the solar cell body is good, but also the cost is low. For example, the bonding pattern 311 may be a 10nm titanium bonding pattern.

In some examples, the thickness of the bonding pattern 311 may be, for example, 1nm, 10nm, 20nm, 30nm, 40nm, or 50nm. In contrast to fig. 2, 3, and 4, the solar cell shown in fig. 5 has no adhesive pattern.

Optionally, the solar cell may further include: a control diffusion pattern (not shown) located between the first conductive pattern 321 and the second conductive pattern 104, the control diffusion pattern being for: the thickness of the alloy formed in the eutectic bonding of the second conductive pattern 104 and the first conductive pattern 321 is controlled to obtain a desired interface alloy region. Specifically, the diffusion pattern is controlled between the first conductive pattern 321 and the second conductive pattern 104, so that the atom diffusion speed of the first conductive pattern 321 and the second conductive pattern 104 in the eutectic bonding process can be slowed down, the thickness of the alloy formed at each position of the eutectic bonding interface is uniform, the thickness of the alloy formed in the eutectic bonding process is not too thick, and the bonding force of the first conductive pattern 321 and the second conductive pattern 104 can be improved. Meanwhile, the diffusion control pattern between the first conductive pattern 321 and the second conductive pattern 104 can also improve the wettability of the first conductive pattern 321 and the wettability of the second conductive pattern 104, so that fewer bubbles are formed in the bonding process of the two, the bonding of the two is more compact, and the bonding force of the first conductive pattern 321 and the second conductive pattern 104 is further improved. Furthermore, the controlled diffusion pattern between the first conductive pattern 321 and the second conductive pattern 104 can prevent eutectic bonding to some extent, and then the solar cell can avoid the continued thickening of the alloy by the atomic diffusion speed of both the first conductive pattern 321 and the second conductive pattern 104 under the heated or cooled condition. The material for controlling the diffusion pattern is not particularly limited. For example, the material of the diffusion controlling pattern may be graphene, may be single-layer graphene or multi-layer graphene, and the shape of the diffusion controlling pattern may be the same as or similar to the shape of the first conductive pattern 321 and the second conductive pattern 104.

Optionally, the thickness of the second conductive pattern 104 is 5-50um, and/or the thickness of the first conductive pattern 321 is 10-100nm. The thickness direction is parallel to the lamination direction of the first conductive pattern 321 and the second conductive pattern 104. The thickness of the second conductive pattern 104 and the thickness of the first conductive pattern 321 are within the above ranges, and the electrode has a good effect of collecting carriers. It should be noted that the directions in which the thicknesses are mentioned throughout are all defined.

By way of example, the thickness of the second conductive pattern 104 may be 5um, 10um, 20um, 30um, 40um, or 50um. By way of example, the thickness of the first conductive pattern 321 may be 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, or 100nm.

Alternatively, referring to fig. 1 to 5, the second conductive pattern 104 is composed of at least two second conductive sub-patterns that are stacked in a stacking direction parallel to the first conductive pattern 321 and the second conductive pattern 104. In fig. 2, a direction of lamination of the first conductive pattern 321 and the second conductive pattern 104 may be parallel as indicated by a dotted line L1. It should be noted that the second conductive pattern 104 is specifically composed of how many second conductive sub-patterns, which is not specifically limited. For example, as shown in fig. 1, 2, 3, and 5, the second conductive pattern 104 is composed of a second conductive sub-pattern 1041 and a second conductive sub-pattern 1042 which are stacked in a stacking direction parallel to the first conductive pattern 321 and the second conductive pattern 104. As another example, as shown in fig. 4, the second conductive pattern 104 is composed of a second conductive sub-pattern 1041, a second conductive sub-pattern 1042, and a second conductive sub-pattern 1043 which are stacked in a stacking direction parallel to the first conductive pattern 321 and the second conductive pattern 104.

Alternatively, the second conductive pattern 104 includes a seed layer pattern and a plating pattern that are stacked in a stacking direction parallel to the solar cell body and the first conductive pattern 321. The plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern. That is, the plating pattern is located between the seed layer pattern and the solar cell body, and the plating pattern is formed on a side of the seed layer pattern close to the solar cell body by electroplating or electroless plating, and thus the plating pattern covers a side of the seed layer pattern close to the solar cell body. The second conductive pattern 104 is formed in a flexible manner by having an interface between the plating pattern and the seed layer pattern. Electroplating is to plate a layer of material with plated patterns on the seed layer pattern by utilizing the electrolysis principle. Electroless plating is to deposit metal ions in the electroless plating solution onto the seed layer pattern by reducing the metal ions to metal with a suitable reducing agent without an applied current. The process parameters such as the temperature of the plating or electroless plating are not particularly limited, and may be suitably used for forming the plating pattern. The specific method of electroless plating is not limited, and may be, for example, lithium plating.

Alternatively, the material of the second conductive sub-pattern 1041 of the second conductive pattern 104 farthest from the first conductive pattern 321 may include tin. The second conductive sub-pattern 1041 of the second conductive pattern 104, which is farthest from the first conductive pattern 321, is also the portion of the electrode farthest from the solar cell body, and the material of the portion includes tin, which can prevent oxidation of the remaining second conductive sub-patterns of the second conductive pattern 104, and has a lower melting point, so that during welding of the solder strip and the electrode, the welding temperature can be lower due to the lower melting point of tin, which is beneficial to reducing the welding temperature of the electrode during forming the cell assembly, so as to reduce the thermal influence to the solar cell or the cell assembly. The material of the second conductive sub-pattern closest to the first conductive pattern 321 in the second conductive pattern 104 may be tin or tin alloy. For example, in the solar cell shown in fig. 4, the material of the second conductive sub-pattern 1041 of the second conductive pattern 104 farthest from the first conductive pattern 321 includes tin, which mainly acts to prevent oxidation of the second conductive sub-pattern 1042 and the second conductive sub-pattern 1043, and during the soldering process of the solder ribbon and the electrode, the soldering temperature may be lower due to the lower melting point of tin, so that the thermal influence to the solar cell or the cell component may be reduced.

The tin alloy may be a copper-tin alloy, a lead-tin alloy, or the like.

The first embodiment also provides a method for manufacturing a solar cell, which can be used to manufacture the solar cell in the first embodiment, and fig. 6 is a flowchart illustrating steps of a method for manufacturing a solar cell according to an embodiment of the present invention. Referring to fig. 6, the method for manufacturing the solar cell includes the steps of:

and step A1, forming a first conductive pattern or a first conductive film layer on the solar cell body.

The first conductive pattern may be formed on the solar cell body in the following manner: and forming a first conductive pattern on the region to be provided with the electrode on the solar cell body by adopting screen printing, deposition, electroplating and other modes. Alternatively, the first conductive pattern is formed by forming the entire first conductive film layer on the solar cell body and patterning the first conductive film layer. For example, the first conductive film layer 321 may be formed by vacuum deposition such as vacuum sputtering deposition or the like. If the entire first conductive film layer 321 is formed, a mask layer may be disposed on the first conductive film layer 321, the mask layer may be patterned, and the first conductive pattern 321 may be formed by wet etching. Alternatively, the first conductive film layer 321 may be patterned using a laser to form the first conductive pattern 321. In the present embodiment, this is not particularly limited.

Fig. 7 is a schematic view illustrating a partial structure of a first HJT solar cell according to an embodiment of the present invention. Fig. 8 is a schematic view illustrating a partial structure of a second type HJT solar cell according to an embodiment of the present invention. Fig. 9 is a schematic diagram of a partial structure of a first HBC solar cell according to an embodiment of the present invention. Fig. 10 is a schematic diagram of a partial structure of a second HBC solar cell according to an embodiment of the present invention. Referring to fig. 8 and 10, a first conductive film layer 321 is formed on the solar cell body by screen printing, deposition, electroplating, or the like.

Alternatively, forming the first conductive pattern or the first conductive film layer on the solar cell body may include: and paving a metal foil on the solar cell body to form a first conductive film layer. The metal foil is then patterned to form a first conductive pattern. The patterning manner is not particularly limited. The metal foil is made of the same material as the first conductive pattern or the first conductive film layer.

Optionally, after the metal foil is laid on the solar cell body, the method may include: and pressing the metal foil to enable the metal foil to be attached to the solar cell body. Specifically, if the solar cell body has a pyramid shape, the gap between the two may be relatively obvious, so that the metal foil and the solar cell body are better attached by pressing, which is beneficial to eutectic bonding alignment and improvement of reliability of the electrode. The pressing mode is not particularly limited, for example, the surface of the metal foil can be cleaned after pressing by a roller, so that pollution of pressing substances to the surface of the metal foil and the like can be reduced. In the embodiment of the present invention, this is not particularly limited.

And step A2, forming a second conductive pattern on the imprinting template.

It should be noted that, in the embodiment of the present application, the imprint template may be a rigid template or a flexible template.

Fig. 11 is a schematic view of a partial structure of a first embodiment of the present application for forming a second conductive pattern, and fig. 12 is a schematic view of a partial structure of a second embodiment of the present application for forming a second conductive pattern. Fig. 13 is a schematic view showing a partial structure of a third embodiment of the present application for forming a second conductive pattern. Fig. 14 is a schematic view showing a partial structure of a fourth embodiment of the present application for forming a second conductive pattern. Fig. 15 is a schematic view showing a partial structure of a fifth embodiment of the present application for forming a second conductive pattern. Referring to fig. 11 to 15, the second conductive pattern 104 is formed on the imprint template. For example, an entire second conductive film layer is formed on the imprint template, and then the second conductive pattern 104 is formed by laser etching. The impression template mainly has the following functions: the imprint template may be used as a component for carrying the second conductive pattern 104 during eutectic bonding of the second conductive pattern 104 to the first conductive pattern or first conductive film layer 321 on the solar cell body. The second conductive patterns 104 shown in fig. 12 and 13 are each composed of a second conductive sub-pattern 1041 and a second conductive sub-pattern 1042 which are stacked in a stacking direction parallel to the first conductive pattern 321 and the second conductive pattern 104. The second conductive pattern 104 shown in fig. 15 is composed of a second conductive sub-pattern 1041, a second conductive sub-pattern 1042, and a second conductive sub-pattern 1043 which are stacked in a stacking direction parallel to the first conductive pattern 321 and the second conductive pattern 104.

In some examples, forming the second conductive pattern 104 on the imprint template includes: in fig. 11, a second conductive sub-pattern 1041 is formed on the imprint template, and in fig. 12, a second conductive sub-pattern 1042 is formed on the second conductive sub-pattern 1041.

In other examples, forming the second conductive pattern 104 on the imprint template includes: in fig. 13, a second conductive sub-pattern 1041 is formed on the imprint template, and in fig. 14, a second conductive sub-pattern 1042 is formed on the second conductive sub-pattern 1041. In fig. 15, a second conductive sub-pattern 1042 is formed on the second conductive sub-pattern 1041, and then a second conductive sub-pattern 1043 is formed on the second conductive sub-pattern 1042.

The manner of forming the second conductive pattern 104 on the imprint template may include: electroplating, deposition and the like. The second conductive pattern 104 is formed on the imprint template instead of being prepared on the solar cell body, and the preparation process of the second conductive pattern 104 has little or no influence on the solar cell body, can reduce the influence on the solar cell body, and is easy to realize mass production.

Step A3, aligning the second conductive pattern with the first conductive pattern, and eutectic bonding the second conductive pattern with the first conductive pattern; or aligning the second conductive pattern with the region of the first conductive film layer where the electrode is to be formed, and eutectic bonding the second conductive pattern with the region of the first conductive film layer where the electrode is to be formed.

The second conductive pattern 104 is aligned with the first conductive pattern 321, where the alignment may be: the first projection of the second conductive pattern 104 on the solar cell body and the second projection of the first conductive pattern 321 on the solar cell body have overlapping areas, and the size of the overlapping areas is not particularly limited. For example, the area size of the first projection may be equal to the area size of the second projection, and the area of the overlapping region is smaller than the area of the first projection, or the area size of the first projection may be equal to the area size of the second projection, and the area size of the overlapping region may be equal to the area size of the first projection, or the area of the second projection may be larger than the area of the first projection, and the first projection completely falls into the second projection. It should be noted that all references to alignment are the same or similar to the definition of alignment herein.

After the first conductive pattern 321 and the second conductive pattern 104 are aligned, the second conductive pattern 104 and the first conductive pattern 321 are bonded together in a eutectic mode, so that the second conductive pattern 104 on the imprinting template is transferred to the first conductive film layer 321 on the solar cell body or the eutectic bonding on the first conductive pattern 321. The eutectic bonding has the characteristics of low bonding temperature and high bonding strength, and the low bonding temperature can enable the solar cell body to be less affected by heat and has little influence on the photoelectric conversion efficiency of the solar cell. The high bonding strength can make the reliability of the electrode of the solar cell good. The second conductive pattern, the first conductive film layer, or the first conductive pattern of the present invention may be formed of a material that can be eutectic bonded with respect to screen printing, and is not limited to silver paste, so that the cost can be suitably reduced. Compared with laser transfer printing, the invention has the advantages that the second conductive pattern and the first conductive pattern are bonded together in an eutectic way, or the second conductive pattern and the region to be formed with the electrode in the first conductive film layer are bonded together in an eutectic way, the eutectic bonding process is mature, the process difficulty is relatively low, and the production efficiency can be properly improved. Compared with electroplating, the invention has the advantages that the second conductive pattern and the first conductive pattern are bonded together in an eutectic way, or the second conductive pattern and the region to be formed with the electrode in the first conductive film layer are bonded together in an eutectic way, so that the solar cell body has no technical problems of coiling and plating and the like, the yield and the reliability are good, and the mass production is easy to realize.

The alignment of the second conductive pattern 104 with the region of the first conductive film 321 where the electrode is to be formed is similar to the alignment of the second conductive pattern 104 with the first conductive pattern 321, which may be referred to as the above description, and the same or similar beneficial effects can be achieved, so that the repetition is avoided and will not be repeated here.

The second conductive pattern 104 and the region to be formed with the electrode in the first conductive film 321 may be co-crystallized together, or the related description of co-crystallized bonding the second conductive pattern 104 and the first conductive pattern 321 may be referred to, and the same or similar beneficial effects may be achieved, so that the repetition is avoided, and the description is omitted here.

Fig. 16 is a schematic structural diagram illustrating alignment of a first second conductive pattern and a region of a first conductive film layer where an electrode is to be formed according to an embodiment of the present invention. Fig. 17 is a schematic structural diagram illustrating alignment of a second conductive pattern with a region of a first conductive film layer where an electrode is to be formed according to an exemplary embodiment of the present invention. Fig. 18 is a schematic structural diagram illustrating alignment of a third second conductive pattern with a region of a first conductive film layer where an electrode is to be formed according to an embodiment of the present invention. Referring to fig. 16, 17, and 18, the second conductive pattern 104 is aligned with a region of the first conductive film layer 321 where an electrode is to be formed, and the second conductive pattern 104 is eutectic bonded with the region of the first conductive film layer 321 where the electrode is to be formed. Fig. 16 and 18 mainly differ in the number of second conductive patterns 104, the structure of the solar cell body, and the number of second conductive sub-patterns in the second conductive patterns 104. Fig. 16 and 17 differ mainly in the shape of the second conductive pattern 104.

And step A4, removing the imprinting template.

The second conductive pattern 104 on the imprint template is transferred to the first conductive film layer 321 on the solar cell body or the eutectic bond on the first conductive pattern 321, and thus an electrode of the solar cell is basically formed, and then the imprint template is removed. Here, the removal of the imprint template may be performed by a mechanical external force or the like, and in the embodiment of the present invention, the manner of removing the imprint template is not particularly limited. The removal of the imprinting template mainly depends on that the bonding force between the second conductive pattern 104 and the imprinting template is smaller than the eutectic bonding force between the second conductive pattern 104 and the first conductive film 321 or the first conductive pattern 321, so as to remove the imprinting template. Optionally, a coating or the like having a coating that makes the second conductive pattern 104 easier to disengage from the imprint template may be applied between the imprint template and the second conductive pattern 104, further facilitating removal of the imprint template. For example, the imprinting stamp and the second conductive pattern 104 may have tin or a tin alloy therebetween, which has a low melting point, and may be easily removed by heating.

FIG. 19 is a third exemplary embodiment of the present invention _HJT Schematic partial structure of solar cell. Fig. 20 is a schematic diagram of a partial structure of a third HBC solar cell according to an embodiment of the present invention. Fig. 19 and 20 are schematic views of the solar cell after the imprint template is removed.

It should be noted that, after the imprint template is removed, the second conductive pattern remained on the imprint template may be cleaned with acid solution or alkali solution, so that the imprint template may be reused, thereby further reducing the cost. Specifically, whether to wash the imprint template with an acid solution or an alkali solution is determined according to the material of the second conductive pattern, which is not specifically limited in this embodiment.

And step A5, removing the part of the first conductive film layer except for the electrode area to be formed, and forming a first conductive pattern in the case of forming the first conductive film layer on the solar cell body.

The first conductive film layer 321 is disposed on the solar cell body in a whole layer, and a removing solution corresponding to the material in the first conductive film layer 321 can be used to remove the portion outside the electrode region in the first conductive film layer 321, so as to form a first conductive pattern, thereby avoiding the problems of short circuit and the like.

It should be noted that, the concentration of the removing liquid and/or the removing time may be controlled, so as to further control the accuracy of forming the first conductive pattern, so as to obtain the first conductive pattern with a relatively suitable shape, which is not particularly limited in this embodiment.

Referring to fig. 2 to 5, a schematic structure may be shown after removing the portion of the first conductive film layer except the electrode region to form the first conductive pattern 321.

Optionally, before the step A3, the method may further include: the second conductive pattern 104 is recrystallized by annealing the imprint template on which the second conductive pattern 104 is formed, so that stress is removed, and the second conductive pattern 104 is annealed on the imprint template instead of being annealed after the second conductive pattern 104 is transferred to the solar cell body, so that the annealing does not have a thermal effect on the solar cell body and does not have a bad effect on the photoelectric conversion efficiency of the solar cell.

Optionally, the annealing temperature is: 200-700 ℃, and the annealing time is as follows: annealing in this temperature range for 0.5-2 minutes, the stress relief of the second conductive pattern 104 on the imprint template is more thorough and energy efficient. For example, the annealing temperature is 200℃and the annealing time is 30 seconds. For another example, the annealing temperature is 700℃and the annealing time is 2 minutes. For another example, the annealing temperature is 400℃and the annealing time is 60 seconds. For another example, the annealing temperature is 700℃and the annealing time is 45 seconds.

Optionally, the annealing temperature is: 500-700 ℃, and the annealing time is as follows: at this annealing temperature and annealing time, the degree of stress relief of the second conductive pattern 104 on the imprint template, and the energy saving are well balanced for 1 minute.

The annealing method may be infrared heating, ultrasonic heating, resistance heating, or the like, and is not particularly limited in the embodiment of the present invention.

Optionally, before eutectic bonding, the method may further include: a control diffusion pattern is formed on the first conductive pattern or a region of the first conductive film layer where an electrode is to be formed, and/or a control diffusion pattern is formed on the second conductive pattern. The control diffusion pattern is used to control the thickness of the alloy formed in eutectic bonding of the second conductive pattern and the first conductive pattern to obtain a desired eutectic bonded alloy region. The materials, structures, etc. of the diffusion controlling pattern may be referred to in the foregoing related descriptions, and may achieve the same or similar advantageous effects, and in order to avoid repetition, the description is omitted herein. The manner of forming the diffusion-controlling pattern may be by deposition, coating, or the like.

Optionally, before forming the first conductive pattern or the first conductive film layer on the solar cell body, the method may further include: forming an adhesive pattern or an adhesive film layer on the solar cell body, the adhesive pattern or the adhesive film layer being used to promote a bonding force between the first conductive pattern and the solar cell body, forming the first conductive pattern may include: the first conductive pattern is formed on the adhesive pattern or the adhesive film layer. The formation of the adhesive film layer means that the entire layer is formed on the solar cell body, and the adhesive pattern is obtained after patterning the entire adhesive film layer. The manner of forming the bonding pattern may be as follows: the method includes forming a whole layer of adhesive film layer on a solar cell body by screen printing, electroplating, depositing and the like, forming a mask on the adhesive film layer, patterning the mask, and wet etching to obtain an adhesive pattern, or patterning the adhesive film layer by laser to obtain the adhesive pattern, which is not particularly limited in this embodiment. The material of the adhesive pattern and the like can be referred to the above-mentioned related descriptions, and can achieve the same or similar advantageous effects, and in order to avoid repetition, the description thereof will be omitted.

As shown with reference to fig. 7 and 9, before forming the first conductive film layer 321 on the solar cell body, the method may further include: an adhesive film layer 311 is formed on the solar cell body. Referring to fig. 8 and 10, the first conductive film layer 321 is formed, and includes: a first conductive film layer 321 is formed on the adhesive film layer 311. After eutectic bonding, the method may further include: the portion of the adhesive film layer 311 other than the electrode region is removed to form the adhesive pattern 311, so that a short circuit or the like is avoided as much as possible. The portions of the adhesive film layer 311 other than the electrode regions may be removed, and the removal liquid corresponding to the material in the adhesive film layer 311 may be selected, and the concentration and/or the removal time of the removal liquid may be controlled to obtain the adhesive pattern 311 having a precise shape.

Fig. 21 is a schematic structural view of a first imprint template according to an exemplary embodiment of the present invention. Alternatively, referring to fig. 21, the imprint template includes a first groove 103, and referring to fig. 11 and 12, the foregoing step A2 may include: a second conductive pattern 104 is formed in the first groove 103 of the imprint template. The second conductive pattern 104 is flush with the surface of the side of the imprint template where the first groove 103 is provided, or protrudes from the surface of the side of the imprint template where the first groove 103 is provided, so that the second conductive pattern 104 can be in contact with the first conductive pattern 321 or the region of the first conductive film 321 where the electrode is to be formed in the process of eutectic bonding the second conductive pattern 104 to the first conductive pattern 321 or the region of the first conductive film 321 where the electrode is to be formed. The first groove 103 serves as a gate line pattern corresponding to the second conductive pattern 104, so that the second conductive pattern 104 with precise shape can be formed conveniently. The formation of the second conductive pattern in the first groove 103 of the imprint template may be achieved by electroplating, deposition, or the like, which is not particularly limited in this embodiment. It should be noted that, if the deposition method is selected, after the deposition, the second conductive film layer located in the outer area of the first groove 103 needs to be etched away.

For example, a first recess 103 is opened inward in a localized area of the surface of the substrate 101 to form an imprint template. Referring to fig. 17, in transferring the eutectic bond of the second conductive pattern 104 to the electrode region to be provided on the first conductive film layer 321 on the solar cell body, the surface of the substrate may be a surface of the substrate 101 close to the solar cell body. If the second conductive pattern 104 is formed in the first groove 103 by electroplating, the surface of the first groove 103 needs to be a conductive surface, and the rest of the surface of the substrate 101 is a non-conductive surface. A non-conductive hard or soft substrate may be selected, a conductive material is deposited on the hard or soft substrate, a portion of the conductive material remote from the hard substrate is oxidized to a non-conductive material to form the substrate 101, and then the first recess 103 is opened inward from the non-conductive material such that the conductive material under the non-conductive material at the bottom of the first recess 103 is exposed, the exposed conductive material serves as a cathode for electroplating, and the remaining surface of the substrate 101 is a non-conductive surface that is not electroplated during electroplating to form an imprint template. The size of the first groove 103 is not particularly limited, and for example, the notch of the first groove 103 may be elongated, and the width of the notch of the first groove 103 may be 10um.

The hard substrate here is not particularly limited as long as it has a certain supporting hardness, and the thickness and material of the hard substrate are not particularly limited. The material of the conductive substance and the nonconductive substance is not particularly limited. For example, the hard matrix may be a ceramic having a thickness of 5 nm. An aluminum layer may be deposited on the 5nm ceramic, for example, by sputtering, evaporation, or the like to form a 20um aluminum layer. The aluminum layer is then oxidized such that a portion of the thickness of the aluminum layer distal from the ceramic oxidizes to aluminum oxide, while the remaining aluminum layer proximal to the ceramic is not oxidized. The thickness of the oxidized aluminum layer and the non-oxidized aluminum layer is not particularly limited herein, and for example, the thickness of the oxidized aluminum may be 10um and the thickness of the non-oxidized aluminum layer may be 10um. Laser etching may then be used to open the grooves so that a portion of the alumina is removed until the aluminum layer is exposed. During the electroplating process, the alumina is not electroplated, but only the aluminum layer at the bottom of the first groove 103 is electroplated.

Optionally, referring to fig. 21, the imprint template further includes a substrate 101, and the first groove 103 is disposed on the substrate 101. The imprint template further comprises a first land 102 provided on the substrate 101 and located at the edge of the first recess 103. Referring to fig. 11 and 12, forming the second conductive pattern 104 in the first groove 103 of the imprint template includes: the second conductive pattern 104 is formed in the first recess 103 of the imprint template and in the region defined by the first land 102. The second conductive pattern 104 is flush with the surface of the first boss 102 away from the substrate 101, or protrudes from the surface of the first boss 102 away from the substrate 101. Referring to fig. 17, since the first boss 102 protrudes from the substrate 101, only a portion of the second conductive pattern 104 protruding from the surface of the first boss 102 away from the substrate 101 or only a portion of the second conductive pattern 104 flush with the surface of the first boss 102 away from the substrate 101 is in contact with the region of the first conductive film 321 where the electrode is to be disposed, the rest of the imprint template is not in contact with the first conductive film 321, so that contamination of the first conductive film 321 or the solar cell body can be avoided, and the imprint template can be prevented from pressing the first conductive film 321 or the solar cell body.

It should be noted that the second conductive pattern is not formed on the surface of the first boss 102 away from the substrate 101, which is advantageous in that waste can be reduced and current loss can be reduced. More specifically, if the surface of the first land 102 away from the substrate 101 is formed with the second conductive pattern, the projection of the portion of the second conductive pattern on the surface of the substrate 101 near the first land 102 does not overlap with the projection of the second conductive pattern located in the first groove 103 and in the area defined by the first land 102 on the surface of the substrate 101 near the first land 102, the carriers collected by the portion need to be transferred in the direction parallel to the width of the notch of the first groove 103 to be able to be guided out, and the carrier transfer path is long, which may cause a certain current loss, so that in some examples, the surface of the first land 102 away from the substrate 101 is not formed with the second conductive pattern, which may reduce the current loss and reduce the waste of the second conductive pattern material. The implementation manner that the second conductive pattern is not formed on the surface of the first boss 102 away from the substrate 101 may be: in the process of depositing and forming the second conductive pattern, the second conductive pattern is also deposited on the surface of the first boss 102 far from the substrate 101, then a mask is provided, the mask is patterned, and wet etching is performed to remove the second conductive pattern formed on the surface of the first boss 102 far from the substrate 101. Or in the process of depositing and forming the second conductive pattern, the second conductive pattern formed on the surface of the first boss 102 far from the substrate 101 is removed by adopting a laser etching mode. Still alternatively, the areas defined by the first lands 102 on both sides are provided as conductive surfaces, and the surfaces of the first lands 102 away from the substrate 101 are provided as non-conductive surfaces. The specific method comprises the following steps: the portion of the first lands 102 near the substrate 101 may be selected to be conductive, then a non-conductive material is disposed on the portion of the first lands 102 near the substrate 101 by deposition or coating, and then the non-conductive material in the area defined by the first lands 102 on both sides is etched, so that the area defined by the first lands 102 on both sides is a conductive surface, and the surface of the first lands 102 far from the substrate 101 is a non-conductive surface, and in the electroplating process, the second conductive pattern can be electroplated on the area defined by the first lands 102 on both sides as a cathode, and the surface of the first lands 102 far from the substrate 101 cannot be electroplated on the second conductive pattern.

Note that, the first boss 102 may be integrally formed with the substrate 101, or the first boss 102 and the substrate 101 may be separately manufactured, and then the first boss 102 and the substrate 101 may be fixedly connected together by using a glue layer or the like, which is not particularly limited in this embodiment.

Alternatively, referring to fig. 21, the cross-sectional area of the first groove 103 is gradually reduced along the direction from the notch of the first groove 103 to the bottom of the groove, wherein the cross-sectional area of the first groove 103 is perpendicular to the lamination direction of the first conductive pattern 321 and the second conductive pattern 104, and further the cross-sectional area of the second conductive pattern 104 formed along the direction from the notch of the first groove 103 to the bottom of the groove is also gradually reduced, which is advantageous for reducing light shielding and reducing reflection.

Fig. 22 is a schematic structural view of a second imprint template according to an exemplary embodiment of the present invention. Fig. 23 is a schematic structural view of a third imprint template according to an exemplary embodiment of the present invention. Fig. 24 is a schematic structural view of a fourth imprint template according to an exemplary embodiment of the present invention. Alternatively, referring to fig. 22 to 24, the imprint template includes a substrate 101 and a second land 202 on the substrate 101. The number of the second bosses 202 on the substrate 101 is not particularly limited. For example, the imprint template shown in fig. 22 has two second lands 202 on the substrate 101, the imprint template shown in fig. 23 has three second lands 202 on the substrate 101. It should be noted that, in this embodiment, the substrate 101 and the second boss 202 may be formed by one-step molding or separately, which is not particularly limited. The imprint template shown in fig. 24 has three second lands 202 on the substrate 101. It should be noted that, in this embodiment, the substrate 101 and the second boss 202 may be formed by one-step molding or separately, which is not particularly limited. Referring to fig. 13 and 14, the step A2 may include: the second conductive film layer 104 is formed on the side of the imprint template where the second boss 202 is formed, and a portion of the second conductive film layer 104 located on the second boss 202 is a second conductive pattern. For the second conductive film layer 104 formed by deposition, electroplating, or the like, the height difference between the second boss 202 and the substrate 101 may be utilized, so that the portion of the second conductive film layer 104 located on the second boss 202 and the portion located on the substrate 101 are disconnected, on one hand, after the second conductive pattern 104 is aligned with the first conductive pattern 321 or the region to be provided with the electrode in the first conductive film layer 321, only the portion located on the second boss 202 is ensured to be in contact with the first conductive pattern 321, so that the alignment of the second conductive pattern 104 and the first conductive pattern 321 is facilitated, and meanwhile, the portion of the second conductive film layer 104 located on the substrate 101 is not in contact with the first conductive pattern 321 or the region to be provided with the electrode in the first conductive film layer 321, so that pollution to the first conductive film layer 321 or the solar cell body may be reduced, on the other hand, only the second boss 202 in the imprint template is indirectly contacted with the first conductive film layer 321 or the solar cell body, and the rest of the imprint template is not contacted with the first conductive pattern 321 or the solar cell body, so that the imprint template is removed.

The second conductive film layer 104 may be a metal foil, and the step A3 may be: a metal foil is laid on the side of the imprint template where the second bump 202 is formed, and a portion of the metal foil located on the second bump 202 is the second conductive pattern 104. The portion outside the second boss 202 may be attached to the substrate 101 by lamination or the like, preventing displacement of the metal foil, or the like. For example, the surface of the metal foil can be cleaned after the lamination by the roller, so that the pollution of lamination substances to the surface of the metal foil and the like can be reduced. In the embodiment of the present invention, this is not particularly limited. Also, by adsorbing the portion of the metal foil located outside the second bump 202 on the substrate 101, after the second conductive pattern 104 is aligned with the first conductive pattern 321 or the region of the first conductive film 321 where the electrode is to be disposed, it is ensured that only the portion located on the second bump 202 is in contact with the first conductive pattern 321, facilitating the alignment of the second conductive pattern 104 with the first conductive pattern 321, and at the same time, the portion of the second conductive film 104 located on the substrate 101 is not in contact with the first conductive pattern 321 or the region of the first conductive film 321 where the electrode is to be disposed, so that contamination to the first conductive film 321 or the solar cell body can be reduced. At this time, the portion of the metal foil located on the second bump 202 and the portion located outside the second bump 202 may not be broken before eutectic bonding, and may be broken after eutectic bonding. The material of the metal foil may be the same as that of the second conductive pattern 104, and in order to avoid repetition, a description thereof will be omitted. For example, the metal foil may be copper foil or the like.

The surface of the second boss 202 far away from the substrate 101 may have a small burr or the like, which may hold the metal foil, so that the second conductive pattern is not easy to generate position offset or the like in the alignment eutectic bonding process between the second conductive pattern and the first conductive pattern or the region of the first conductive film layer where the electrode is to be disposed. The material of the metal foil is the same as or similar to the material of the second conductive pattern described above. For example, the metal foil may be copper foil.

Alternatively, referring to fig. 22 or 24, the surface of the second bump 202 remote from the substrate 101 is planar, and the surface of the second conductive pattern 104 thus formed close to the second bump 202 is also planar.

Alternatively, referring to fig. 23, the side of the second boss 202 remote from the substrate 101 includes a second recess 2021, forming a second conductive pattern on the imprint template, including: a second conductive pattern is formed in the second groove 2021, where the surface of the second groove 2021 on the first land 202 serves as a reticle. For example, the area of the cross section of the second groove 2021 is gradually reduced in a direction approaching the substrate 101, and thus, in the finally formed solar cell, the cross section of the portion of the second conductive pattern 104 away from the solar cell body is gradually reduced in a direction away from the solar cell body, and reflection and shading can be reduced. Here, the second conductive pattern is flush with the notch of the second groove 2021 or protrudes from the second groove 2021.

Optionally, the imprinting template includes a possible substrate, and the step A2 may include: and paving a metal foil on the substrate, and patterning the metal foil to form a second conductive pattern. That is to say, a metal foil is laid on the whole layer of the substrate, and then patterning is carried out by means of laser etching and the like, so that a second conductive pattern is formed. The material of the metal foil and the like may be the same as the material of the second conductive pattern 104 or the second conductive film layer 104, and in order to avoid repetition, a description thereof will be omitted.

Optionally, before the step A2, the method may further include: a number of metal foil patterns are provided. The imprinting stamp may include a plurality of adsorption areas, and the step A2 may include: at least one suction area and one metal foil pattern are aligned, and the metal foil pattern is sucked onto the suction area to form a second conductive pattern on the imprint template. For example, the imprint template may include a substrate and a number of adsorption regions disposed on the substrate at intervals. At least one suction area and one metal foil pattern are aligned, and the metal foil pattern is sucked on the suction area to form a second conductive pattern on the substrate. Where the suction zone may be located in a localized area on one surface of the substrate. Alternatively, for example, the substrate may have a bump thereon, the bump may have an adsorption region thereon, at least one adsorption region on the bump may be aligned with one of the metal foil patterns, and the metal foil pattern may be adsorbed on the adsorption region to form the second conductive pattern on the bump of the substrate. The alignment herein may refer to the alignment definition previously described, and will not be repeated here.

For example, the substrate may have a hollow structure, and a vacuum adsorption member, a magnet, or the like may be partially disposed in the hollow structure of the substrate, and the metal foil pattern is adsorbed by the vacuum adsorption member, the magnet, or the like. In the embodiment of the present invention, specific adsorption modes and the like are not particularly limited.

Fig. 25 is a schematic structural diagram of a fourth HJT solar cell according to an embodiment of the present invention. Alternatively, as shown in fig. 25, the second conductive pattern 104 may be a metal line 1044, and the shape and size of the metal line 1044 are not particularly limited. For example, metal line 1044 may have a wire diameter of 10-50 microns and a length of 10-1000 microns. The material of the metal line 1044 may be the same as that of the second conductive pattern, which is not described herein. For example, the metal line 1044 may be made of copper, aluminum, or the like.

Optionally, referring to fig. 25, the surface of the metal wire 1044 may be further coated with a coating 1045, and the material of the coating 1045 may include: nickel, tin, conductive paste, and the like, the coating 1045 of the above material has excellent conductivity, and can appropriately reduce contact resistance between the metal line 1044 and the first conductive pattern 321 or the first conductive film layer 321, and the like. The thickness of the coating 1045 is not particularly limited, and for example, the thickness of the coating 1045 may be 1 to 10 micrometers.

The metal wire can be arranged in the first groove 103 or the second groove of the imprinting template, and can be clamped, and after the metal wire is clamped, the metal wire is flush with the notch of the first groove 103 and the notch of the second groove, or the metal wire protrudes out of the notch of the first groove 103 and the notch of the second groove, so that a second conductive pattern is formed on the imprinting template.

If a whole layer of metal foil is laid on the solar cell body, the metal foil may be partially damaged at the boundary of the eutectic bonding due to the high temperature of the eutectic bonding during the eutectic bonding. Thus, after eutectic bonding, the areas of the metal foil other than the electrodes may be removed by: this is not particularly limited in the present embodiment by blowing off with an air stream, or sticking off with a viscous material, or the like.

Fig. 26 is a schematic structural view of a fifth imprint template according to an exemplary embodiment of the present invention. Fig. 27 is a schematic view showing a partial structure of a sixth embodiment of the present invention for forming a second conductive pattern. Fig. 28 is a schematic view of a seventh partial structure for forming a second conductive pattern according to an exemplary embodiment of the present invention. Optionally, referring to fig. 27 to 28, the step A2 may include: a seed pattern 1047 is formed on the imprint template, and a plating pattern 1048 is formed on the seed pattern 1047 using electroplating or electroless plating, and the plating pattern 1048 and the seed pattern 1047 together form a second conductive pattern 104. The role of the imprint template here is mainly to: since the receiving base for forming the seed pattern 1047 may be provided, the structure of the imprint template is not limited. For example, referring to fig. 26, the imprint template may include only the substrate 101. The seed pattern 1047 may be formed by deposition, printing, or the like, and the forming method of the seed pattern 1047 is not limited. The material of the plating pattern 1048 may be a material suitable for electroplating or electroless plating, for example, the material of the plating pattern 1048 may be nickel or the like. The material of the seed pattern 1047 may be a material of the seed layer, and for example, the material of the seed pattern 1047 may be copper or the like. In the step A3, the plated pattern 1048 in the second conductive pattern 104 is aligned with the first conductive portion, and the plated pattern 1048 in the second conductive pattern 104 is soldered with the first conductive portion, so that the second conductive pattern 104 is flexibly formed.

For example, referring to fig. 28, in the lamination direction of the solar cell body and the first conductive pattern 321, the second conductive pattern 104 is composed of a seed layer pattern 1047 and a plating pattern 1048 which are laminated. The plating pattern 1048 is close to the solar cell body with respect to the seed layer pattern 1047, and the plating pattern 1048 covers the seed layer pattern 1047. The materials of the plating pattern 1048 and the seed layer pattern 1047 may be described with reference to the foregoing.

Example two

The second embodiment provides another solar cell, which includes a solar cell body, and a positive electrode and a negative electrode disposed on the solar cell body; the structure of the positive electrode and the structure of the negative electrode may be the same or different. The electrode (which may be a positive electrode or a negative electrode) of the solar cell includes: a second conductive pattern laminated on the solar cell body; wherein the second conductive pattern is eutectic bonded on the solar cell body.

The solar cell body refers to the related descriptions in the first embodiment, and the description thereof is omitted to avoid repetition. For example, the solar cell body may be a silicon substrate, and if a passivation layer is further disposed on the solar cell body, the passivation layer may be grooved so that the silicon substrate is exposed.

The second conductive pattern is bonded on the solar cell body in a eutectic mode, the eutectic bonding process is simple and mature, and mass production is easy to realize. Meanwhile, the eutectic bonding has the characteristics of low bonding temperature and high bonding strength, and the low bonding temperature can enable the solar cell body to be less affected by heat and has little influence on the photoelectric conversion efficiency of the solar cell. The high bonding strength can make the reliability of the electrode of the solar cell good. In eutectic bonding, the material of the second conductive pattern can be bonded with the solar cell body in a eutectic manner, the material is not limited to silver paste, the material selectivity is high, compared with silver paste, copper, tin and the like can be selected, for example, so that the cost can be properly reduced, the silver paste is granular, the contact among silver particles is less, the silver paste contains organic components, the organic components can influence the contact among the silver particles, the resistivity of the silver paste electrode is higher, the conductivity is poor, the material of the electrode in the embodiment of the invention can be other than granular (for example, silver paste), the material of the electrode can be silver, copper, tin and alloys thereof, and the like, so that the conductivity of the electrode is better. In addition, since the second conductive pattern 104 may not be prepared on the solar cell body, the preparation process of the second conductive pattern has little or no effect on the solar cell body, and mass production is easy to achieve, and the preparation cost may be reduced.

The material of the second conductive pattern may be a material that can be eutectic bonded to the solar cell body, and the material of the second conductive pattern is not particularly limited. For example, the material of the second conductive pattern may include nickel, aluminum, gold, e.g., the material of the second conductive pattern may be elemental nickel or nickel alloy, or the material of the second conductive pattern may be aluminum, or the material of the second conductive pattern may be gold. The material of the second conductive pattern can be bonded with the solar cell body at the temperature of about 800-900 ℃ and lower, the eutectic bonding process is simple and mature, and mass production is easy to realize. Meanwhile, the combination temperature of about 800-900 ℃ and lower makes the solar cell body less affected by heat. And the eutectic bonding strength is high, so that the reliability of the electrode of the solar cell is good. For example, the material of the second conductive pattern may be gold, which may achieve good eutectic bonding with silicon in the solar cell body at a temperature of 370 ℃.

Meanwhile, the second conductive pattern may be eutectic bonded to the solar cell body, rather than being limited to silver paste, compared to screen printing, and thus the cost can be suitably reduced. Compared with laser transfer printing, the invention has the advantages that the second conductive pattern and the solar cell body are bonded together in a eutectic way, the eutectic bonding process is mature, the process difficulty is relatively low, and the production efficiency can be properly improved. Compared with electroplating, the method has the advantages that the second conductive pattern and the solar cell body are bonded together in an eutectic mode, the solar cell body is free of technical problems such as winding plating, the yield and the reliability are good, and mass production is easy to achieve.

Alternatively, the second conductive pattern 104 includes a seed layer pattern and a plating pattern that are stacked in a stacking direction parallel to the solar cell body and the first conductive pattern 321. The plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern. The same or similar advantages can be achieved by referring to the relevant descriptions in the first embodiment, and the description is omitted here for avoiding repetition.

Optionally, the shape, thickness, structural composition, etc. of the second conductive pattern in the second embodiment may be the same as those described in the first embodiment, and may achieve the same or similar beneficial effects, so that the description is omitted here for avoiding repetition.

Optionally, the solar cell may further include: a control diffusion pattern between the second conductive pattern and the solar cell body, the control diffusion pattern for: the second conductive pattern and the thickness of the alloy formed in eutectic bonding with the solar cell body are controlled to obtain an ideal interface alloy region, and possible influences on the solar cell body in the eutectic bonding process can be avoided. For the material and structure of the diffusion pattern, reference may be made to the descriptions related to the first embodiment, and the same or similar advantageous effects may be achieved, so that the description is omitted here for avoiding repetition.

The second embodiment also provides a method for manufacturing a solar cell, which may be used to manufacture the solar cell in the second embodiment, and fig. 29 is a flowchart illustrating steps of another method for manufacturing a solar cell according to an embodiment of the present invention. Referring to fig. 29, the method for manufacturing the solar cell includes the steps of:

step S1, forming a second conductive pattern on the imprint template.

Step S1 can refer to the related descriptions in the first embodiment, and can achieve the same or similar beneficial effects, and in order to avoid repetition, the description is omitted here.

And S2, aligning the second conductive pattern with the area of the solar cell body where the electrode is to be formed, and eutectic bonding the second conductive pattern to the area of the solar cell body where the electrode is to be formed.

The alignment in step S2 may also refer to the related descriptions in the first embodiment, and in order to avoid repetition, the description is omitted here. Step S2 achieves a transfer of the second conductive pattern onto the solar cell body,

and step S3, removing the imprinting template.

Step S3 may refer to the related descriptions in the first embodiment, and may achieve the same or similar beneficial effects, so that the description is omitted here for avoiding repetition.

Optionally, before eutectic bonding, the method may further include: the imprint template formed with the second conductive pattern is annealed so that the second conductive pattern is recrystallized to relieve stress. The annealing temperature, annealing time, annealing mode, etc. may be the same as those described in the first embodiment, and may achieve the same or similar beneficial effects, so that repetition is avoided and detailed description is omitted.

Optionally, before eutectic bonding, the method may further include: a control diffusion pattern is formed on the second conductive pattern and/or on a region of the solar cell body where an electrode is to be formed. The control diffusion pattern is used for controlling the thickness of the alloy formed in eutectic bonding of the second conductive pattern and the region of the solar cell body where the electrode is to be formed, so as to obtain an ideal eutectic bonding alloy region. The materials, structures, forming manners of the control diffusion patterns may correspond to those described in the first embodiment, and may achieve the same or similar advantages, so that the description is omitted here for avoiding repetition.

Alternatively, referring to fig. 21, the imprint template includes a first groove 103, and referring to fig. 11 and 12, the foregoing step S1 may include: a second conductive pattern 104 is formed in the first groove 103 of the imprint template. The second conductive pattern 104 is flush with the surface of the side of the imprinting mold where the first groove 103 is provided, or protrudes from the surface of the side of the imprinting mold where the first groove 103 is provided. The formation of the second conductive pattern in the first recess 103 of the imprint template may refer to the description of the first embodiment, and may achieve the same or similar advantages, and in order to avoid repetition, the description is omitted here.

Alternatively, referring to fig. 21, the imprint template further includes a substrate 101, the first groove 103 is disposed on the substrate 101, and the imprint template may further include a first land 102 disposed on the substrate 101 and located at an edge of the first groove 103. The step S1 may include: a second conductive pattern 104 is formed in the first groove 103 and in the region defined by the first land 102. The second conductive pattern 104 is flush with the surface of the first boss 102 away from the substrate 101, or protrudes from the surface of the first boss 102 away from the substrate 101. Reference should be made to the description of the first embodiment, and the same or similar advantages can be achieved, so that the description is omitted here for avoiding repetition.

Alternatively, referring to fig. 21, the area of the cross section of the first groove 103 is gradually reduced along the direction from the notch of the first groove 103 to the bottom of the groove, wherein the cross section of the first groove 103 is perpendicular to the lamination direction of the second conductive pattern and the solar cell body, and the area of the cross section of the formed second conductive pattern is gradually reduced along the direction from the notch of the first groove 103 to the bottom of the groove, which is beneficial to reducing light shielding and reducing reflection. Reference should be made to the description of the first embodiment, and the same or similar advantages can be achieved, so that the description is omitted here for avoiding repetition.

Alternatively, referring to fig. 22 to 24, the imprint template includes a substrate 101 and a second land 202 on the substrate 101. The number of the second bosses 202 on the substrate 101 is not particularly limited. Referring to fig. 13 and 14, the step S1 may include: a second conductive pattern is formed at a side of the imprint template where the second boss 202 is formed. The manner of forming the second conductive patterns, the number of second bosses, etc. may all correspond to the relevant descriptions in the first embodiment, and may achieve the same or similar beneficial effects, and in order to avoid repetition, the description is omitted here. Alternatively, referring to fig. 23, the side of the second boss 202 remote from the substrate 101 includes a second recess 2021, forming a second conductive pattern on the imprint template, including: a second conductive pattern is formed in the second groove 2021. The shape, function, etc. of the second groove 2021 may be the same as those described in the first embodiment, and may achieve the same or similar advantages, so that the description is omitted here for avoiding repetition.

Optionally, the surface of the second boss 202 away from the substrate 101 is planar, or alternatively, a side of the second boss 202 away from the substrate 101 includes a second groove (not shown in the figure), where the second conductive pattern 104 is flush with the notch of the second groove, or protrudes from the second groove. Here, the same or similar advantages can be achieved by referring to the related descriptions in the first embodiment, and in order to avoid repetition, the description is omitted here.

Alternatively, referring to fig. 22 and 24, the imprint template includes a substrate 101. The step S1 may include: and paving a metal foil on the substrate, and patterning the metal foil to form a second conductive pattern. Here, the same or similar advantages can be achieved by referring to the related descriptions in the first embodiment, and in order to avoid repetition, the description is omitted here.

Optionally, before the step S1, the method may further include: a number of metal foil patterns are provided. The imprinting stamp may include a plurality of adsorption areas, and the step S1 may include: at least one suction area and one metal foil pattern are aligned, and the metal foil pattern is sucked onto the suction area to form a second conductive pattern on the imprint template. For example, the imprint template may include a substrate and a number of adsorption regions disposed on the substrate at intervals. The step S1 may include: at least one suction area and one metal foil pattern are aligned, and the metal foil pattern is sucked on the suction area to form a second conductive pattern on the substrate. Alternatively, for example, the substrate may have a bump thereon, the bump may have an adsorption region thereon, at least one adsorption region on the bump may be aligned with one of the metal foil patterns, and the metal foil pattern may be adsorbed on the adsorption region to form the second conductive pattern on the bump of the substrate. Here, the same or similar advantages can be achieved by referring to the related descriptions in the first embodiment, and in order to avoid repetition, the description is omitted here.

Fig. 30 is a schematic view illustrating a partial structure of a solar cell according to an embodiment of the present invention. Alternatively, referring to fig. 30, the material of the second conductive pattern 104 is aluminum, and the second conductive pattern 104 is in contact with the silicon substrate 305 in the solar cell body. The aforementioned step S2 may include: in the process of eutectic bonding the second conductive pattern 104 to the region of the solar cell body where the electrode is to be formed, part of aluminum in the second conductive pattern 104 diffuses into the region of the silicon substrate 305 where the electrode is to be formed, so that the region of the silicon substrate 305 where the electrode is to be formed is doped to form a P-type doped region 3051, and the remaining part of the second conductive pattern 104 serves as an electrode. That is, by means of the shape of the second conductive pattern 104 of aluminum material and the distribution position on the solar cell body, and at the same time, by means of the temperature during the eutectic bonding, the local P-type doping of the silicon substrate 305 is realized during the process of transferring the second conductive pattern 104 of aluminum material to the solar cell body, so that the step of performing the local P-type doping exclusively is not required, and the production efficiency can be improved. A portion of the aluminum in the second conductive pattern 104 may diffuse into the region of the silicon substrate 305 where the electrode is to be formed, centered around the contact location of the second conductive pattern with the silicon substrate 305. Note that, the concentration of the P-type dopant formed by diffusing part of the aluminum in the second conductive pattern 104 into the region of the silicon substrate 305 where the electrode is to be formed is not particularly limited.

Alternatively, as shown in fig. 30, the second conductive pattern 104 of aluminum material may be an aluminum metal line 1044, and the shape and size of the aluminum metal line 1044 are not limited.

Alternatively, referring to fig. 26 to 28, the step S1 may include: a seed pattern 1047 is formed on the imprint template, and a plating pattern 1048 is formed on the seed pattern 1047 using electroplating or electroless plating, and the plating pattern 1048 and the seed pattern 1047 together form a second conductive pattern 104. The role of the imprint template here is mainly to: the carrying platform for forming the seed pattern may be provided, and the same or similar advantages may be achieved by referring to the related description in the first embodiment, so that the description is omitted here for avoiding repetition.

Optionally, the step S1 may include: at least two layers of aluminum conductive sub-patterns are formed on the imprinting template in a stacked manner. Because, in the process of aligning the second conductive pattern 104 with the area of the solar cell body where the electrode is to be formed, the aluminum conductive sub-pattern located on the side of the second conductive pattern 104 away from the imprint template is in direct contact with the silicon substrate 305, so that, in the process of diffusing part of aluminum in the second conductive pattern 104 of aluminum material into the silicon substrate 305, the aluminum conductive sub-pattern located on the side of the second conductive pattern 104 away from the imprint template preferentially diffuses into the silicon substrate 305, and under the condition that the eutectic bonding heat is constant, the rest of the aluminum conductive sub-pattern may or may not diffuse into the silicon substrate 305, that is, during the diffusion process, the aluminum conductive sub-pattern located on the side away from the imprint template is equivalent to properly protecting the rest of the aluminum conductive sub-pattern, so that the rest of the aluminum conductive sub-pattern diffuses less, and the shape deformation of the rest of the aluminum conductive sub-pattern is less, and the rest of the aluminum conductive sub-pattern acts as an electrode, so that the precision of the formed electrode can be ensured.

For example, as shown in fig. 30, the aluminum conductive sub-pattern may be an aluminum metal line 1044, and the shape, size, etc. of the aluminum metal line 1044 are not particularly limited. The aluminum conductive sub-pattern of the side of the second conductive pattern 104 remote from the imprint template may be an aluminum paste sub-pattern 1046. In the eutectic bonding process, the aluminum paste sub-pattern 1046 located on the side of the aluminum metal line 1044 away from the imprint template is in direct contact with the silicon substrate 305, so that in the process of diffusing part of aluminum in the second conductive pattern 104 of the aluminum material into the silicon substrate 305, the aluminum paste sub-pattern 1046 can be preferentially diffused into the silicon substrate 305, and under the condition of certain heat of eutectic bonding, the aluminum metal line 1044 can be partially diffused into the silicon substrate 305, or can not be diffused into the silicon substrate 305, that is, in the diffusion process, the aluminum paste sub-pattern 1046 on the side of the aluminum paste sub-pattern 1046 away from the imprint template is equivalent to properly protecting the aluminum metal line 1044, so that the aluminum metal line 1044 is less diffused, and the shape of the aluminum metal line 1044 is less deformed, and the aluminum metal line 1044 can be used as an electrode subsequently, so that the precision of the formed electrode can be ensured.

The invention will be further illustrated by the following examples in conjunction with the more detailed examples.

As shown in fig. 4, the second conductive sub-pattern 1041 is a tin conductive sub-pattern with a thickness of 1um, the second conductive sub-pattern 1042 is a copper conductive sub-pattern with a thickness of 12um, and the second conductive sub-pattern 1043 is a tin conductive sub-pattern with a thickness of 0.5 um. The second conductive sub-pattern 1041, the second conductive sub-pattern 1042 and the second conductive sub-pattern 1043 are all prepared by deposition and patterning.

In fig. 4, the first conductive pattern 321 is a copper conductive pattern having a thickness of 20nm, and the first conductive pattern 321 is deposited. The bonding pattern 311 was a titanium pattern having a thickness of 10nm, and the bonding pattern 311 was also deposited. The first conductive pattern 321 and the second conductive pattern 104 are eutectic bonded together.

It should be noted that the solar cell, the method for manufacturing the solar cell, and the cell assembly can be referred to each other, and the same or similar beneficial effects can be achieved.

It should be noted that, for simplicity of description, the method embodiments are shown as a series of acts, but it should be understood by those skilled in the art that the embodiments are not limited by the order of acts, as some steps may occur in other orders or concurrently in accordance with the embodiments. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred, and that the acts are not necessarily all required in accordance with the embodiments of the application.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and many forms may be made by those having ordinary skill in the art without departing from the spirit of the present invention and the scope of the claims, which are to be protected by the present invention.

Claims

1. A method of manufacturing a solar cell, comprising:

Forming a second conductive pattern on the imprint template;

removing the imprinting template;

2. The method of claim 1, further comprising, prior to eutectic bonding:

annealing the imprint template formed with the second conductive pattern such that the second conductive pattern is recrystallized.

3. The method of manufacturing a solar cell according to claim 1 or 2, wherein prior to eutectic bonding, the method further comprises:

Forming a control diffusion pattern on the first conductive pattern or a region of the first conductive film layer where an electrode is to be formed; and/or forming a control diffusion pattern on the second conductive pattern;

4. The method of manufacturing a solar cell according to claim 1 or 2, wherein before forming the first conductive pattern or the first conductive film layer on the solar cell body, the method further comprises:

the method further comprises the steps of forming an adhesive film layer on the solar cell body, and after the imprinting template is removed, removing the adhesive film layer: and removing the part of the bonding film layer except the region where the electrode is to be formed, and forming the bonding pattern.

5. The method of manufacturing a solar cell according to claim 1 or 2, wherein the imprint template comprises a first groove; the forming of the second conductive pattern on the imprint template includes:

forming the second conductive pattern in the first groove of the imprinting template;

6. The method of claim 5, wherein the imprint template includes a substrate, the first groove is disposed on the substrate, and the imprint template further includes a first boss disposed on the substrate and located at an edge of the first groove; the forming the second conductive pattern in the first groove of the imprint template includes:

7. The method of manufacturing a solar cell according to claim 5, wherein the cross-sectional area of the first groove gradually decreases in a direction from a notch of the first groove to a bottom of the groove; wherein the cross section is perpendicular to a lamination direction of the first conductive pattern and the second conductive pattern.

8. The method of manufacturing a solar cell according to claim 1 or 2, wherein the imprint template includes a substrate and a second boss provided on the substrate;

the forming of the second conductive pattern on the imprint template includes:

9. The method for manufacturing a solar cell according to claim 8, wherein,

the surface of the second boss, which is far away from the substrate, is a plane;

or, the side of the second boss away from the substrate comprises a second groove, wherein the second conductive pattern is flush with the notch of the second groove or protrudes out of the second groove.

10. The method of manufacturing a solar cell according to claim 1 or 2, wherein the forming of the second conductive pattern on the imprint template includes:

forming a seed pattern on the imprint template;

11. The method of manufacturing a solar cell according to claim 1 or 2, wherein the imprint template includes a substrate, and the forming of the second conductive pattern on the imprint template includes:

12. The method of manufacturing a solar cell according to claim 1 or 2, wherein before forming the second conductive pattern on the imprint template, the method further comprises:

providing a plurality of metal foil patterns;

13. A solar cell, comprising:

a solar cell body;

14. The solar cell of claim 13, wherein the first conductive pattern is proximate to the solar cell body relative to the second conductive pattern;

15. The solar cell according to claim 14, wherein the second conductive pattern or a partial region of the second conductive pattern distant from the solar cell body has a triangular, trapezoidal, or a pattern formed by a segment of an arc and a segment connecting both ends of the arc, the segment having a length smaller than or equal to a diameter of a circle corresponding to the arc; wherein the longitudinal section is parallel to a lamination direction of the first conductive pattern and the second conductive pattern.

16. The solar cell according to any one of claims 13-15, wherein the solar cell further comprises: and the bonding pattern is arranged between the first conductive pattern and the solar cell body and is used for improving the bonding force between the first conductive pattern and the solar cell body.

17. The solar cell according to any one of claims 13-15, wherein the solar cell further comprises: and a control diffusion pattern disposed between the first conductive pattern and the second conductive pattern, the control diffusion pattern being used to control a thickness of an alloy formed in eutectic bonding of the second conductive pattern and the first conductive pattern.

18. The solar cell according to any one of claims 13-15, wherein in a stacking direction of the first conductive pattern and the second conductive pattern, the second conductive pattern is composed of at least two layers of second conductive sub-patterns stacked.

19. The solar cell according to any one of claims 13 to 15, wherein in a lamination direction of the solar cell body and the first conductive pattern, the second conductive pattern includes a seed layer pattern and a plating pattern that are laminated; the plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern.

20. A method of manufacturing a solar cell, comprising:

forming a second conductive pattern on the imprint template;

and removing the imprinting template.

21. The method of claim 20, further comprising, prior to eutectic bonding:

22. The method of claim 20 or 21, wherein prior to eutectic bonding, the method further comprises:

forming a control diffusion pattern on the second conductive pattern and/or forming a control diffusion pattern on a region of the solar cell body where an electrode is to be formed;

23. The method of claim 20 or 21, wherein the imprint template comprises a first groove; the forming of the second conductive pattern on the imprint template includes:

24. The method of claim 23, wherein the imprint template includes a substrate, the first groove is disposed on the substrate, and the imprint template further includes a first boss disposed on the substrate and located at an edge of the first groove; the forming the second conductive pattern in the first groove of the imprint template includes:

25. The method of manufacturing a solar cell according to claim 23, wherein the cross-sectional area of the first groove gradually decreases in a direction from a notch of the first groove to a bottom of the groove; wherein the cross section is perpendicular to a lamination direction of the second conductive pattern and the solar cell body.

26. The method of claim 20 or 21, wherein the imprint template comprises a substrate and a second boss on the substrate;

the forming of the second conductive pattern on the imprint template includes:

27. The method of claim 26, wherein the surface of the second boss remote from the substrate is planar; or, the side of the second boss away from the substrate comprises a second groove, wherein the second conductive pattern is flush with the notch of the second groove or protrudes out of the second groove.

28. The method of manufacturing a solar cell according to claim 20 or 21, wherein the forming a second conductive pattern on the imprint template comprises:

forming a seed pattern on the imprint template;

29. The method of claim 20 or 21, wherein the imprint template includes a substrate, and the forming the second conductive pattern on the imprint template includes:

30. The method of claim 20 or 21, wherein prior to forming the second conductive pattern on the imprint template, the method further comprises:

providing a plurality of metal foil patterns;

31. The method of manufacturing a solar cell according to claim 20 or 21, wherein the material of the second conductive pattern is aluminum, and the second conductive pattern is in contact with a silicon substrate in the solar cell body;

32. A solar cell, comprising:

a solar cell body;

and a second conductive pattern disposed on the solar cell body;

33. The solar cell according to claim 32, wherein an area of the second conductive pattern or a cross section of a partial region of the second conductive pattern away from the solar cell body is gradually reduced in a direction away from the solar cell body; wherein the cross section is perpendicular to a lamination direction of the second conductive pattern and the solar cell body.

34. The solar cell according to claim 32, wherein the second conductive pattern or a partial region of the second conductive pattern away from the solar cell body has a triangular, trapezoidal, or a pattern formed by a segment of an arc and a line segment connecting both ends of the arc, the length of the line segment being smaller than or equal to the diameter of a circle corresponding to the arc; wherein the longitudinal section is parallel to a lamination direction of the second conductive pattern and the solar cell body.

35. The solar cell according to any one of claims 32-34, wherein the solar cell further comprises: and the control diffusion pattern is arranged between the second conductive pattern and the solar cell body and is used for controlling the thickness of an alloy formed in eutectic bonding of the second conductive pattern and the solar cell body.

36. The solar cell according to any one of claims 32-34, wherein in a stacking direction of the solar cell body and the second conductive pattern, the second conductive pattern is composed of at least two layers of second conductive sub-patterns that are stacked.

37. The solar cell according to any one of claims 32 to 34, wherein in a lamination direction of the solar cell body and the second conductive pattern, the second conductive pattern includes a seed layer pattern and a plating pattern that are laminated; the plating pattern is close to the solar cell body relative to the seed layer pattern, and the plating pattern coats the seed layer pattern.

38. The battery module is characterized by comprising a first packaging adhesive film, a solar cell string and a second packaging adhesive film which are sequentially stacked; the solar cell string is formed by sequentially connecting a plurality of solar cells in series;

wherein the solar cell is a solar cell according to any one of claims 13-19, 32-37.