CN118016737A - Solar cell and preparation method thereof - Google Patents
Solar cell and preparation method thereof Download PDFInfo
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- CN118016737A CN118016737A CN202410102429.5A CN202410102429A CN118016737A CN 118016737 A CN118016737 A CN 118016737A CN 202410102429 A CN202410102429 A CN 202410102429A CN 118016737 A CN118016737 A CN 118016737A
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- 238000002360 preparation method Methods 0.000 title claims abstract description 20
- 239000002002 slurry Substances 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 42
- 238000005245 sintering Methods 0.000 claims abstract description 28
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 230000003287 optical effect Effects 0.000 claims description 10
- 230000001678 irradiating effect Effects 0.000 claims description 8
- 238000000926 separation method Methods 0.000 claims description 6
- 229910052751 metal Inorganic materials 0.000 abstract description 9
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- 238000002844 melting Methods 0.000 abstract description 8
- 239000002184 metal Substances 0.000 abstract description 8
- 229910045601 alloy Inorganic materials 0.000 abstract description 7
- 239000000956 alloy Substances 0.000 abstract description 7
- 229910010272 inorganic material Inorganic materials 0.000 abstract description 7
- 239000011147 inorganic material Substances 0.000 abstract description 7
- 238000002309 gasification Methods 0.000 abstract description 5
- 210000004027 cell Anatomy 0.000 description 56
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- 230000005641 tunneling Effects 0.000 description 5
- 238000002161 passivation Methods 0.000 description 4
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 4
- 229920005591 polysilicon Polymers 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 229910052581 Si3N4 Inorganic materials 0.000 description 3
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 3
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 2
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- 238000011056 performance test Methods 0.000 description 2
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- 238000007650 screen-printing Methods 0.000 description 2
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- 238000010023 transfer printing Methods 0.000 description 2
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- Photovoltaic Devices (AREA)
Abstract
The invention relates to a solar cell and a preparation method thereof. The preparation method comprises the following steps: setting grid line slurry on the battery main body; applying a bias voltage between the battery body and the gate line paste; and performing a laser-assisted sintering process on the gate line slurry, wherein in the laser-assisted sintering process, the laser energy density on the gate line region is smaller than that on the two side regions of the gate line region. The laser energy density of the two side regions is relatively high to form a sufficiently large current, and the generated heat can melt the metal and the inorganic material so that the two mutually diffuse to form an alloy and form good ohmic contact. The energy density of the grid line area is relatively low or even 0, so that the melting or gasification phenomenon of the grid line in the sintering process is reduced, and the condition that the efficiency of the battery is influenced due to the change of the height-width ratio and the surface morphology of the grid line is reduced. The laser process window of the preparation method of the solar cell is larger.
Description
Technical Field
The invention relates to the technical field of photovoltaics, in particular to a solar cell and a preparation method thereof.
Background
After the grid line sizing agent is printed on the solar cell, the solar cell needs to be sintered to form a metalized grid line. The laser assisted sintering essentially uses the high concentration and controllable characteristic of the energy density of laser to separate the two key steps of corrosion and contact formation of the surface film layer in the high-temperature sintering process, thereby achieving the effect of accurately regulating and controlling the sintering process. The principle of laser-assisted sintering is that laser irradiates the grid line slurry, current generated by the laser irradiates the grid line slurry to conduct along a path with low contact resistance under the action of external bias voltage, and in a short time, high-intensity current generates huge heat to melt metal, silicon nitride, silicon oxide and other inorganic materials, so that the metal and the silicon nitride are mutually diffused to form an alloy, thereby reducing contact resistance and improving filling factor. The duration of the sintering process is matched with the service life of the current carrier, and the laser is stopped rapidly within millisecond level after passing, so that the heat can not damage the surface film layers of other areas, and the battery efficiency is improved.
When the energy density of the laser is higher, the laser can melt and even gasify the surface of the grid line when irradiated on the grid line, thereby changing the aspect ratio and the surface morphology of the grid line and affecting the battery efficiency. For this reason, lower laser energy densities are typically used to reduce melting or vaporization of the grid lines. However, since the laser-assisted sintering needs to have a certain laser energy density to generate a sufficiently large current, if the laser energy density is insufficient, the generated current is insufficient to melt the metal and the inorganic material, a good ohmic contact cannot be formed, and the battery efficiency is also affected. Therefore, the use of lower laser energy density reduces the thermal impact of laser radiation on the grid line, but too low laser energy density can affect cell efficiency, and the process window for laser assisted sintering is small.
Disclosure of Invention
Based on this, it is necessary to provide a solar cell and a method for manufacturing the same, so as to solve the problem that the cell efficiency is affected by too high or too low energy density of the laser and the process window is small.
One of the purposes of the invention is to provide a preparation method of a solar cell, which comprises the following steps:
a method of fabricating a solar cell, comprising the steps of:
Setting grid line slurry on the battery main body;
Applying a bias voltage between the battery body and the gate line paste;
And performing laser-assisted sintering treatment on the grid line slurry, wherein in the laser-assisted sintering treatment, the laser energy density on the grid line region is smaller than that of the two side regions of the grid line region, and the grid line slurry is positioned on the grid line region.
In one embodiment, a first laser beam is irradiated on the grid line slurry to sinter the grid line slurry; the light spot of the first laser beam comprises a middle area, and a first side area and a second side area which are respectively positioned at two sides of the middle area, wherein the energy density of the first side area and the energy density of the second side area are higher than those of the middle area, the middle area irradiates the grid line slurry, and the first side area and the second side area irradiate two sides of the grid line slurry respectively.
In one embodiment, a second laser beam and a third laser beam are respectively irradiated on two sides of the grid line slurry, so that the grid line slurry is sintered, and the light spots of the second laser beam and the light spots of the third laser beam are arranged at intervals.
In one embodiment, the width of the middle region is greater than or equal to the width of the gate line paste.
In one embodiment, the ratio of the width of the middle region to the width of the gate line paste is (1.2-2) to 1.
In one embodiment, the intermediate region has a width of 20 μm to 60 μm.
In one embodiment, the width of the first side region and the width of the second side region are independently 50 μm to 150 μm. In one embodiment, the energy density of the intermediate region is 0.02J/cm 2～0.1J/cm2.
In one embodiment, the energy density of the first side region and the energy density of the second side region are independently 0.2J/cm 2～1J/cm2.
In one embodiment, the first laser beam is obtained by converting a gaussian laser beam through a diffractive optical element.
In one embodiment, the gaussian laser is a round laser.
In one embodiment, the energy density of the second laser beam and the energy density of the third laser beam are independently 0.2J/cm 2～1J/cm2.
In one embodiment, the separation distance between the spot of the second laser beam and the spot of the third laser beam is 10 μm to 50 μm larger than the width of the grid line slurry.
Another object of the present invention is to provide a solar cell prepared by the preparation method according to any one of the above embodiments.
Compared with the traditional scheme, the preparation method of the solar cell has the following beneficial effects:
In the method for manufacturing the solar cell, the grid line slurry arranged on the cell main body is subjected to a laser-assisted sintering process, and in the laser-assisted sintering process, the laser energy density of the grid line region is smaller than that of the two side regions of the grid line region. The laser energy density of the two side regions is relatively high to form a sufficiently large current, and the generated heat can melt the metal and the inorganic material so that the two mutually diffuse to form an alloy and form good ohmic contact. The energy density of the grid line area is relatively low or even 0, so that the melting or gasification phenomenon of the grid line in the sintering process is reduced, and the condition that the efficiency of the battery is influenced due to the change of the height-width ratio and the surface morphology of the grid line is reduced. The laser process window of the preparation method of the solar cell is larger.
The solar cell avoids the damage to the grid line caused by high-energy-density laser irradiation, and the grid line and the cell body can form good ohmic contact, so that higher filling factor and conversion efficiency can be obtained.
Drawings
Fig. 1 is a schematic flow chart of a method for manufacturing a solar cell according to an embodiment of the invention;
fig. 2 is a schematic view of disposing a grid line slurry on a battery body and irradiating with a first laser beam;
FIG. 3 is a graph of the positional relationship of the spot of the first laser beam and the grid line slurry, which is shown in broken lines in the figure;
FIG. 4 is a schematic diagram of a manner of generating a first laser beam;
FIG. 5 is a schematic flow chart of a method for manufacturing a solar cell according to another embodiment of the invention;
FIG. 6 is a schematic view of a grid line slurry disposed on a battery body and irradiated with a second laser beam and a third laser beam;
fig. 7 is a positional relationship diagram of the spots of the second laser beam and the third laser beam and the grid line slurry, which is shown in the figure with a broken line.
Reference numerals illustrate:
10. A solar cell; 100. a battery main body; 110. a substrate; 120. a tunneling layer; 130. a doped polysilicon layer; 140. a first functional layer; 150. an emitter; 160. a second functional layer; 20. gate line slurry; 30. a first laser beam; 31. a middle region; 32. a first side region; 33. a second side region; 40. a second laser beam; 50. a third laser beam; 60. a laser source; 70. a diffractive optical element; 80. and a lens.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but are provided to provide a more thorough understanding of the present disclosure.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.
In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and are not to be interpreted as indicating or implying a relative importance or order of such features.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The invention provides a preparation method of a solar cell, which comprises the following steps:
Setting grid line slurry on the battery main body;
Applying a bias voltage between the battery body and the gate line paste;
and performing laser-assisted sintering treatment on the grid line slurry, wherein the laser energy density on the grid line region is smaller than that of the two side regions of the grid line region, and the grid line slurry is positioned on the grid line region.
In the method for manufacturing the solar cell, the grid line slurry arranged on the cell main body is subjected to a laser-assisted sintering process, and in the laser-assisted sintering process, the laser energy density of the grid line region is smaller than that of the two side regions of the grid line region. The laser energy density of the two side regions is relatively high to form a sufficiently large current, and the generated heat can melt the metal and the inorganic material so that the two mutually diffuse to form an alloy and form good ohmic contact. The energy density of the grid line area is relatively low or even 0, so that the melting or gasification phenomenon of the grid line in the sintering process is reduced, and the condition that the efficiency of the battery is influenced due to the change of the height-width ratio and the surface morphology of the grid line is reduced. The laser process window of the preparation method of the solar cell is larger.
As shown in fig. 1, a method 100 for manufacturing a solar cell according to an embodiment of the invention includes the following steps:
Step S110, disposing a gate line paste on the battery body.
As shown in fig. 2, the solar cell 10 is TOPCon cells (tunneling layer passivation contact cells). For TOPCon cells, the efficiency potential of laser assisted sintering is higher than for PERC cells (emitter and back passivation cells) due to the use of burn-through paste for both the front and back sides.
More specifically, the cell body 100 of the solar cell 10 includes a substrate 110, a tunneling layer 120, a doped polysilicon layer 130, a first functional layer 140, an emitter 150, and a second functional layer 160.
The tunneling layer 120 is disposed on a first side of the substrate 110. The doped polysilicon layer 130 is disposed on the tunneling layer 120, and the first functional layer 140 is disposed on the doped polysilicon layer 130. The emitter 150 is disposed on a second side of the substrate 110. The second functional layer 160 is disposed on the emitter 150. The first and second functional layers 140 and 160 may be, but are not limited to, passivation layers, anti-reflection layers, and the like. The material of the passivation layer may be, but is not limited to, one or more of the aluminum oxide film layers. The material of the anti-reflection layer may be, but is not limited to, one or more of silicon nitride film layers. The gate line paste 20 is disposed on the first and second functional layers 140 and 160.
Alternatively, the solar cell 10 is not limited to TOPCon cells, but may be BC-type cells, for example.
In one example, the grid line paste 20 is disposed on the battery body through a coating process. The coating may be one or more of, but not limited to, screen printing, pad printing, spin coating, slot coating, spray coating, laser transfer printing.
In one example, the grid line paste 20 is a silver powder paste.
In one example, the width W 4 of the gate line paste 20 is 10 μm to 30 μm. Further, 15 μm to 30 μm. In one example, the width W 4 of the gate line paste 20 is 20 μm to 30 μm. In some specific examples, the width W 4 of the gate line paste 20 includes, but is not limited to, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, and the like.
In the present invention, "width" refers to a dimension in a direction perpendicular to an extending direction of the gate line paste.
Step S120 of applying a bias voltage between the battery body and the gate line paste 20.
In one example, the specific step of applying the bias voltage includes:
and an external power supply is used for applying bias voltage to the battery body through the bottom conductive platform and the top conductive probe row. The magnitude of the bias voltage is 5V-20V.
In step S130, as shown in fig. 2 and 3, the first laser beam 30 is irradiated onto the grid line slurry 20, so that the grid line slurry 20 is sintered. The spot of the first laser beam 30 includes a middle region 31, a first side region 32 and a second side region 33 located at both sides of the middle region 31, respectively, the energy density of the first side region 32 and the second side region 33 is higher than that of the middle region 31, the middle region 31 is irradiated on the gate line paste 20, and the first side region 32 and the second side region 33 are irradiated at both sides of the gate line paste 20, respectively.
The formation of the first laser beam 30 may be accomplished by optical path design or by using optics to provide a zoned distribution of laser radiation energy.
As shown in fig. 4, in one example, the first laser beam 30 is obtained by generating a gaussian laser using a laser source 60 and then converting the gaussian laser via a Diffractive Optical Element (DOE) 70. After passing through the diffractive optical element 70, the gaussian laser beam can form a spot energy distribution with lower energy in the middle and higher energy on both sides. In one example, the gaussian laser is a gaussian circular laser. The Gaussian round laser passes through the diffraction optical element, and can form rectangular light spots with low energy distribution in the middle and high energy distribution at two sides.
As shown in fig. 4, in one example, the spot of the first laser beam 30 is a rectangular spot. The middle region 31, the first side region 32 and the second side region 33 are three rectangular regions side by side. The first laser beam 30 may be obtained by converting a gaussian circular laser light through a diffractive optical element 70.
In other examples, the spot of the first laser beam 30 is not limited to a rectangular spot, but may be a circular spot, an elliptical spot, or the like, as long as it has an energy distribution characteristic that the energy density of the intermediate region 31 is low and the energy densities of the first side region 32 and the second side region 33 are high.
Further, the gaussian laser light can be passed through the diffractive optical element 70 and then the spot size can be adjusted by the lens 80. The lens 80 is, for example, a concave lens, a convex lens, or the like.
Preferably, the width W 1 of the intermediate region 31 is not less than the width W 4 of the gate line paste 20 in order to align the intermediate region 31 on the gate line paste 20. In one example, the width W 1 of the middle region 31 is the same as the width W 4 of the gate line paste 20. Further, the width W 1 of the intermediate region 31 and the width W 4 of the gate line paste 20 are each any value between 20 μm and 30 μm.
In one example, the width W 1 of the intermediate region 31 is greater than the width W 4 of the gate line paste 20 in order to better cover the intermediate region 31 against the gate line paste 20.
In one example, the ratio of the width W 1 of the intermediate region 31 to the width W 4 of the gate line paste 20 is (1.2-2) to 1. Further, the ratio of the width W 1 of the intermediate region 31 to the width W 4 of the gate line paste 20 is (1.5-2) to 1. In some specific examples, the ratio of the width W 1 of the intermediate region 31 to the width W 4 of the gate line paste 20 includes, but is not limited to, 1.2:1, 1.5:1, 1.8:1, 2:1, and the like.
In one example, the width W1 of the middle region 31 is 10 μm to 50 μm greater than the width W 4 of the gate line paste 20. Further, the width W 1 of the intermediate region 31 is 10 μm to 30 μm larger than the width W 4 of the gate line paste 20. In some specific examples, the width W 1 of the intermediate region 31 is greater than the width W 4 of the gate line paste 20, including but not limited to 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, and the like.
In one example, the width W1 of the intermediate region 31 is 20 μm to 60 μm. Further, the width W1 of the intermediate region 31 is 20 μm to 50 μm. In some specific examples, the width W 1 of the intermediate region 31 includes, but is not limited to, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, and the like.
It will be appreciated that in other examples, the width W 1 of the intermediate region 31 may also be less than the width W 4 of the gate line paste 20, which also reduces the thermal impact of the laser radiation on the gate line to some extent.
In one example, the energy density of the intermediate region 31 is below 0.1J/cm 2. In one example, the energy density of the intermediate region 31 is 0.05J/cm 2～0.1J/cm2. Further, the energy density of the intermediate region 31 was 0.05J/cm 2～0.08J/cm2. The energy density of the intermediate region 31 is within the above range, and the thermal influence of the laser radiation on the gate line can be effectively reduced.
In one example, the first side region 32 and/or the second side region 33 are irradiated outside the gate line paste 20, i.e., there is a space between the first side region 32 and/or the second side region 33 and the gate line paste 20. The width of the space is the width W 4 of the middle region 31 that exceeds the width W 4 of the gate line paste 20 on one side. The energy density of the first side region 32 and the second side region 33 is high to generate a sufficiently large current to generate a sufficiently large amount of heat to melt the metal and silicon material so that they diffuse into each other to form a silicon-containing alloy, thereby reducing contact resistance and increasing the fill factor. At the same time, the first side region 32 and/or the second side region 33 are irradiated outside the grid line slurry 20, reducing the melting or vaporization of the grid lines.
In one example, the width W 2 of the first side region 32 and the width W 3 of the second side region 33 are independently 50 μm to 150 μm. Further, the width W 2 of the first side region 32 and the width W 3 of the second side region 33 are independently 50 μm to 100 μm. The width W 2 of the first side region 32 and the width W 3 of the second side region 33 may be the same or different.
In one example, the energy density of the first side region 32 and the energy density of the second side region 33 are independently 0.2J/cm 2～1J/cm2. Further, the energy density of the first side region 32 and the energy density of the second side region 33 are independently 0.2J/cm 2～0.8J/cm2. The energy density of the first side region 32 and the energy density of the second side region 33 may be the same or different.
In one example, the wavelength of the first laser beam 30 is 532nm to 1064nm.
Alternatively, the first laser beam 30 may be a pulsed laser or a continuous laser. When the first laser beam 30 is a pulsed laser, the pulse width may be, but is not limited to, 30ns to 100 mus.
The above-described method 100 for manufacturing a solar cell performs a laser-assisted sintering process on the grid paste 20 provided on the cell body, and performs sintering by applying a bias voltage and irradiating with the first laser beam 30. The spot of the first laser beam 30 includes a middle region 31 and first and second side regions 32 and 33 located at both sides of the middle region 31, respectively, wherein the energy densities of the first and second side regions 32 and 33 are relatively high to form a sufficiently large current, and the generated heat is capable of melting the metal and the inorganic material so that the two are mutually diffused to form an alloy, forming a good ohmic contact. The middle region 31 is irradiated on the grid line slurry 20, the energy density of the middle region 31 is relatively low, the melting or gasification phenomenon of the grid line in the sintering process is reduced, and the condition that the height-width ratio and the surface morphology of the grid line are changed to influence the efficiency of the battery is reduced. The laser process window of the preparation method 100 of the solar cell is larger.
As shown in fig. 5, a method 200 for manufacturing a solar cell according to another embodiment of the present invention includes the following steps:
step S210, disposing a gate line paste on the battery body.
As shown in fig. 6, the solar cell 10 is TOPCon cells. Alternatively, the solar cell 10 is not limited to TOPCon cells, but may be BC-type cells, for example.
In one example, the grid paste 20 is disposed on the battery body by coating. The coating may be one or more of, but not limited to, screen printing, pad printing, spin coating, slot coating, spray coating, laser transfer printing.
In one example, the grid line paste 20 is a silver powder paste.
In one example, the gate paste 20 is provided in a stripe shape on the battery body.
In one example, the width W 4 of the gate line paste 20 is 10 μm to 30 μm. Further, 15 μm to 30 μm. In one example, the width W 4 of the gate line paste 20 is 20 μm to 30 μm. In some specific examples, the width W 4 of the gate line paste 20 includes, but is not limited to, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, and the like.
Step S220 of applying a bias voltage between the battery body and the gate line paste 20.
In one example, the specific step of applying the bias voltage includes:
and an external power supply is used for applying bias voltage to the battery body through the bottom conductive platform and the top conductive probe row. The magnitude of the bias voltage is 5V-20V.
In step S230, as shown in fig. 6 and 7, the second laser beam 40 and the third laser beam 50 are respectively irradiated on two sides of the grid line slurry 20, so that the grid line slurry 20 is sintered, and the light spots of the second laser beam 40 and the light spots of the third laser beam 50 are arranged at intervals.
In the specific example shown in fig. 7, the spots of the second laser beam 40 and the third laser beam 50 are rectangular spots. In other examples, the spot of the second laser beam 40 and the spot of the third laser beam 50 are not limited to rectangular spots, but may be circular spots, elliptical spots, or the like, for example. As long as there is a space between the spot of the second laser beam 40 and the spot of the third laser beam 50 during irradiation, the grid line slurry 20 is located in the space.
Preferably, the separation distance W 5 between the spot of the second laser beam 40 and the spot of the third laser beam 50 is not less than the width W 4 of the grid line slurry 20. In one example, the spacing distance W 5 is the same as the width W 4 of the gate line paste 20. Further, the above-mentioned spacing distance W 5 and the width W 4 of the gate line paste 20 are each any value between 20 μm and 30 μm.
In one example, the above-described separation distance W 5 is greater than the width W 4 of the grid line slurry 20 to better prevent the second laser beam 40 and the third laser beam 50 from impinging on the grid line slurry 20.
In one example, the spacing distance W 5 is 10 μm to 50 μm greater than the width W 4 of the gate line paste 20. Further, the spacing distance W 5 is 10 μm to 30 μm larger than the width W 4 of the gate line paste 20. In some specific examples, the above-described spacing distance W5 is greater than the width W 4 of the gate line paste 20, including, but not limited to, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, etc.
In one example, the above-mentioned spacing distance W 5 is 10 μm to 50 μm. Further, the distance W 5 is 20 μm to 50 μm. In some specific examples, the above-described separation distance W 5 includes, but is not limited to, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, and the like.
In one example, the width W 6 of the spot of the second laser beam 40 and the width W 7 of the spot of the third laser beam 50 are independently 50 μm to 150 μm. Further, the width W 6 of the spot of the second laser beam 40 and the width W 7 of the spot of the third laser beam 50 are independently 50 μm to 100 μm. The width W 6 of the spot of the second laser beam 40 and the width W 7 of the spot of the third laser beam 50 may be the same or different.
In one example, the energy density of the second laser beam 40 and the energy density of the third laser beam 50 are independently 0.2J/cm 2～1J/cm2. Further, the energy density of the second laser beam 40 and the energy density of the third laser beam 50 are independently 0.2J/cm 2～0.8J/cm2. The energy density of the third laser beam 50 may be the same as or different from the energy density of the third laser beam 50.
In one example, the wavelengths of the second laser beam 40 and the third laser beam 50 are independently 532nm to 1064nm.
Alternatively, the first laser beam 30 and the third laser beam 50 may be pulsed lasers or continuous lasers. When the first laser beam 30 and the third laser beam 50 are pulsed lasers, the pulse width may be, but is not limited to, 30ns to 100ns.
In the above-described method 200 for manufacturing a solar cell, the grid paste 20 provided on the cell body is subjected to a laser-assisted sintering process, and the grid paste 20 is sintered by applying a bias voltage and irradiating both sides thereof with the second laser beam 40 and the third laser beam 50, respectively. The light spots of the second laser beam 40 and the light spots of the third laser beam 50 are arranged at intervals, so that the melting or gasification phenomenon of the grid line in the sintering process is reduced, and the condition that the efficiency of the battery is influenced due to the change of the height-width ratio and the surface morphology of the grid line is reduced. In this manner, the second laser beam 40 and the third laser beam 50 may use a higher energy density to form a sufficiently large current, and the generated heat may be able to melt the metal and the inorganic material so that the two diffuse into each other to form an alloy, forming a good ohmic contact. The laser process window of the preparation method 200 of the solar cell is large.
Furthermore, the invention also provides a solar cell which is prepared by the preparation method.
The solar cell avoids the damage to the grid line caused by high-energy-density laser irradiation, and the grid line and the cell body can form good ohmic contact, so that higher filling factor and conversion efficiency can be obtained.
The present invention is further described below with reference to specific examples and comparative examples, but the present invention is not limited to the following specific examples.
Example 1
The preparation method of the solar cell provided by the embodiment comprises the following steps:
Step 1, as shown in fig. 2 and 3, a gate line paste is provided on TOPCon a battery main body (TOPCon battery). The width W 4 of the gate line paste 20 is 20 μm.
And 2, applying bias between the battery body and the grid line slurry.
Step 3, the first laser beam 30 is irradiated on the grid line slurry 20, so that the grid line slurry 20 is sintered. The spot of the first laser beam 30 comprises a middle region 31, a first side region 32 and a second side region 33 as three rectangular regions side by side.
The first laser beam 30 is a circular gaussian laser generated by a laser source 60, and then the circular gaussian laser is transformed by a Diffractive Optical Element (DOE) to form a spot energy distribution with lower energy in the middle and higher energy on both sides.
The width W 1 of the intermediate region 31 was 40 μm and the energy density was 0.075J/cm 2. The width W 2 of the first side region 32 and the width W 3 of the second side region 33 were each 100 μm, and the energy density was each 0.6J/cm 2.
The grid lines on the front side and the back side of the solar cell are formed by adopting the method.
Example 2
The preparation method of the solar cell provided by the embodiment comprises the following steps:
steps 1 to 2 are the same as steps 1 to 2 in example 1.
And 3, respectively irradiating the two sides of the grid line slurry 20 with a second laser beam 40 and a third laser beam 50 to sinter the grid line slurry 20. The spots of the second laser beam 40 and the third laser beam 50 are rectangular spots and are spaced apart.
The separation distance W 5 between the spot of the second laser beam 40 and the spot of the third laser beam 50 is 40 μm. The width W 6 of the spot of the second laser beam 40 and the width W 7 of the spot of the third laser beam 50 were each 100 μm, and the energy densities were each 0.6J/cm 2.
The grid lines on the front side and the back side of the solar cell are formed by adopting the method.
Comparative example 1
The preparation method of the solar cell of the comparative example comprises the following steps:
steps 1 to 2 are the same as steps 1 to 2 in example 1.
And step 3, irradiating the grid line slurry 20 with a laser beam to sinter the grid line slurry 20. The laser beam used in this comparative example was different from the first laser beam 30 in that the spot had a uniform energy density of 0.075J/cm 2.
The grid lines on the front side and the back side of the solar cell are formed by adopting the method.
Comparative example 2
The preparation method of the solar cell of the comparative example comprises the following steps:
steps 1 to 2 are the same as steps 1 to 2 in example 1.
And step 3, irradiating the grid line slurry 20 with a laser beam to sinter the grid line slurry 20. The laser beam used in this comparative example was different from the first laser beam 30 in that the spot had a uniform energy density of 0.6J/cm 2.
The grid lines on the front side and the back side of the solar cell are formed by adopting the method.
The solar cells prepared in examples 1 to 2 and comparative examples 1 to 2 were subjected to performance tests including open-circuit voltage, short-circuit current, fill factor, and conversion efficiency using an IV test instrument. IV test instrument test conditions STC: AM1.5 spectrum, 1000W/m 2, 25 degrees Celsius, 3A light intensity uniformity distribution. The test results are shown in Table 1.
Table 1 results of performance test of solar cells prepared in examples 1 to 2 and comparative examples 1 to 2
As can be seen from the results in Table 1, the improved laser irradiation method of examples 1 and 2 provided by the invention has improved performance such as solar cell filling factor and conversion efficiency as compared with comparative examples 1 and 2. The laser energy density adopted in comparative example 1 is lower, the generated current is insufficient, and better ohmic contact cannot be formed, while the laser energy density adopted in comparative example 2 is higher, and the laser energy density irradiates on the grid line slurry, so that certain damage is caused to the grid line slurry, and the filling factor and the conversion efficiency are lower.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (10)
1. A method of manufacturing a solar cell, comprising the steps of:
Setting grid line slurry on the battery main body;
Applying a bias voltage between the battery body and the gate line paste;
And performing laser-assisted sintering treatment on the grid line slurry, wherein in the laser-assisted sintering treatment, the laser energy density on the grid line region is smaller than that of the two side regions of the grid line region, and the grid line slurry is positioned on the grid line region.
2. The method of manufacturing of claim 1, wherein the laser assisted sintering process comprises:
Irradiating the grid line slurry with a first laser beam to sinter the grid line slurry; the light spot of the first laser beam comprises a middle area, a first side area and a second side area which are respectively positioned at two sides of the middle area, the energy density of the first side area and the energy density of the second side area are higher than those of the middle area, the middle area irradiates the grid line slurry, and the first side area and the second side area respectively irradiate two sides of the grid line slurry; or alternatively
And respectively irradiating a second laser beam and a third laser beam on two sides of the grid line slurry to sinter the grid line slurry, wherein light spots of the second laser beam and light spots of the third laser beam are arranged at intervals.
3. The method of claim 2, wherein the method of manufacture meets at least one of the following characteristics (1) - (2):
(1) The width of the middle area is larger than or equal to the width of the grid line slurry; -
(2) The ratio of the width of the middle region to the width of the gate line paste is (1.2-2): 1.
4. A production method according to claim 2 or 3, wherein the production method meets at least one of the following features (1) to (2):
(1) The width of the middle area is 30-50 μm;
(2) The width of the first side region and the width of the second side region are each independently 50 μm to 150 μm.
5. A production method according to claim 2 or 3, wherein the production method meets at least one of the following features (1) to (2):
(1) The energy density of the middle area is 0.02J/cm 2 -0.1J/cm 2;
(2) The energy density of the first side region and the energy density of the second side region are independently 0.2J/cm 2～1J/cm2.
6. A method of producing as claimed in claim 2 or 3, wherein the first laser beam is obtained by converting a gaussian laser beam with a diffractive optical element.
7. The method of manufacturing according to claim 6, wherein the gaussian laser is a round laser.
8. The method of claim 2, wherein the energy density of the second laser beam and the energy density of the third laser beam are each independently 0.2J/cm 2～1J/cm2.
9. The method of manufacturing according to claim 2 or 8, wherein a separation distance between the spot of the second laser beam and the spot of the third laser beam is 10 μm to 50 μm larger than the width of the grid line slurry.
10. A solar cell prepared by the preparation method of any one of claims 1 to 9.
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