CN117673178A - Solar cell and photovoltaic module - Google Patents
Solar cell and photovoltaic module Download PDFInfo
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- CN117673178A CN117673178A CN202211098149.9A CN202211098149A CN117673178A CN 117673178 A CN117673178 A CN 117673178A CN 202211098149 A CN202211098149 A CN 202211098149A CN 117673178 A CN117673178 A CN 117673178A
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/042—PV modules or arrays of single PV cells
- H01L31/048—Encapsulation of modules
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0352—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
- H01L31/035272—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions characterised by at least one potential jump barrier or surface barrier
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers
- H01L31/072—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type
- H01L31/0745—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by potential barriers the potential barriers being only of the PN heterojunction type comprising a AIVBIV heterojunction, e.g. Si/Ge, SiGe/Si or Si/SiC solar cells
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- Microelectronics & Electronic Packaging (AREA)
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Abstract
The embodiment of the application relates to the technical field of solar cells, in particular to a solar cell and a photovoltaic module, wherein the solar cell comprises: a substrate having an opposite front side and a back side; the first tunneling layer and the first doped conductive layer are positioned on the front surface of the substrate aligned with the metal pattern area and are sequentially arranged in the direction away from the substrate, and the doping element type of the first doped conductive layer is the same as that of the substrate; the second tunneling layer and the second doped conductive layer are positioned on the back surface of the substrate and are sequentially arranged in the direction away from the substrate, the doping element type of the second doped conductive layer is different from the doping element type of the first doped conductive layer, the activated doping element concentration in the first doped conductive layer is larger than the activated doping element concentration in the second doped conductive layer, and the thickness of the first doped conductive layer is not larger than the thickness of the second doped conductive layer. The embodiment of the application is beneficial to improving the photoelectric conversion performance of the solar cell.
Description
Technical Field
The embodiment of the application relates to the field of solar cells, in particular to a solar cell and a photovoltaic module.
Background
Solar cells have a good photoelectric conversion capability, and in general, in order to inhibit carrier recombination on the surface of a substrate in a solar cell and enhance passivation effect on the substrate, a tunneling oxide layer and a doped conductive layer are generally prepared on the surface of the substrate. Wherein, the doped conductive layer is provided with a doped element.
The doped conductive layer is used for performing a field passivation effect, and the concentration of the doped element in the doped conductive layer plays an important role in the passivation effect of the doped conductive layer, so that the photoelectric conversion performance of the solar cell is affected. However, the current solar cell has the problem of low photoelectric conversion efficiency.
Disclosure of Invention
The embodiment of the application provides a solar cell photovoltaic module, which is at least beneficial to improving the photoelectric conversion efficiency of a solar cell.
The embodiment of the application provides a solar cell, which comprises: a substrate having an opposite front side and a back side; the first tunneling layer and the first doped conductive layer are positioned on the front surface of the substrate aligned with the metal pattern area and are sequentially arranged in the direction away from the substrate, and the doping element type of the first doped conductive layer is the same as that of the substrate; the second tunneling layer and the second doped conductive layer are positioned on the back surface of the substrate and are sequentially arranged in the direction away from the substrate, the doping element type of the second doped conductive layer is different from the doping element type of the first doped conductive layer, the activated doping element concentration in the first doped conductive layer is larger than the activated doping element concentration in the second doped conductive layer, and the thickness of the first doped conductive layer is not larger than the thickness of the second doped conductive layer.
In addition, the thickness of the first doped conductive layer is 20 nm-300 nm, and the thickness of the second doped conductive layer is 50 nm-500 nm.
In addition, the first doped conductive layer comprises a first doped element, the first doped element is activated by annealing to obtain an activated first doped element, and the activation rate of the first doped element in the first doped conductive layer is 40% -80%.
In addition, the activated first doping element has a concentration of 1×10 20 atom/cm 3 ～6×10 20 atom/cm 3 。
In addition, the ratio of the width of each first doped conductive layer to the width of the substrate is 0.0001-0.0012.
In addition, the width of the first doped conductive layer is 20-200 μm.
In addition, the area ratio of the first doped conductive layer on the front surface of the substrate is 0.01-0.15.
In addition, the second doped conductive layer comprises a second doped element, the second doped element is activated by annealing to obtain an activated second doped element, and the activation rate of the second doped element in the second doped conductive layer is 30% -80%.
In addition, the activated second doping element has a concentration of 4×10 19 atom/cm 3 ～9×10 19 atom/cm 3 。
In addition, the second doped conductive layer includes: the first region and the second region are arranged close to the substrate, the slope of the doping curve of the activated second doping element in the first region is not less than 0 in the direction of pointing to the second region along the first region, the slope of the doping curve of the activated second doping element in the second region is less than 0, and the slope of the doping curve is the slope of the curve of the doping concentration of the activated second doping element changing along with the doping depth.
In addition, the slope of the doping curve of the activated second doping element in the first region is 1×e 16 ～1×e 19 The slope of the doping curve of the activated second doping element in the second region is-1×e 16 ～-1×e 20 。
In addition, the concentration of the activated second doping element of the first region is 4×10 19 atom/cm 3 ～9×10 19 atom/cm 3 First, theThe concentration of the activated second doping element of the second region is 1×10 16 atom/cm 3 ～9×10 19 atom/cm 3 。
In addition, the thickness of the second doped conductive layer of the first region is 50 nm-500 nm, and the thickness of the second doped conductive layer of the second region is 30 nm-300 nm.
In addition, the substrate is an N-type substrate, the first doped conductive layer is an N-type doped conductive layer, and the second doped conductive layer is a P-type doped conductive layer.
In addition, the doping element of the first doped conductive layer is phosphorus element, and the doping element of the second doped conductive layer is boron element.
In addition, the material of the first doped conductive layer and the second doped conductive layer includes at least one of amorphous silicon, microcrystalline silicon, or polycrystalline silicon.
In addition, the method further comprises the steps of: and the second part of the first passivation layer is positioned on the front surface aligned with the nonmetallic pattern area.
In addition, the method further comprises the steps of: the first electrode is arranged on the metal pattern area and is electrically connected with the first doped conductive layer.
In addition, the method further comprises the steps of: the diffusion region is positioned in the substrate aligned with the metal pattern region, the top of the diffusion region is in contact with the first tunneling layer, and the doping element concentration of the diffusion region is greater than that of the substrate.
Correspondingly, the embodiment of the application also provides a photovoltaic module, which comprises a battery string, wherein the battery string is formed by connecting a plurality of solar batteries of any one of the above steps; the packaging layer is used for covering a surface cover plate of the battery string, and the cover plate is used for covering the surface, far away from the battery string, of the packaging layer.
The technical scheme provided by the embodiment of the application has at least the following advantages:
in the technical scheme of the solar cell provided by the embodiment of the application, the doping element concentration of the first doped conductive layer is set to be larger than that of the second doped conductive layer, namely, the first doped conductive layer is doped more than the second doped conductive layer, so that the sheet resistance of the first doped conductive layer is lower, and the contact composite loss between the first doped conductive layer and the metal electrode is improved. And the thickness of the first doped conductive layer is smaller, so that parasitic absorption of the first doped conductive layer to incident light irradiated to the front surface can be reduced. The concentration of doping elements of the second doped conductive layer is smaller, auger recombination of the second doped conductive layer can be reduced, passivation performance of the second doped conductive layer is kept, recombination centers of carriers in a PN junction formed by the second doped conductive layer and the substrate are smaller, concentration of the carriers is increased, and open-circuit voltage and short-circuit current are improved. In addition, as the thickness of the second doped conductive layer is larger, the risk that the doped element of the second doped conductive layer is diffused into the substrate due to the fact that the second doped conductive layer is too thin can be reduced, so that the problem that a dead layer is formed due to the fact that the doped element of the second doped conductive layer is accumulated at the interface of the substrate can be avoided, the transmission efficiency of carriers is improved, and the generation of carrier recombination centers is reduced.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise.
Fig. 1 is a schematic cross-sectional structure of a solar cell according to an embodiment of the present disclosure;
FIG. 2 is a graph showing the variation of doping concentration of a second doping element with doping depth;
FIG. 3 is a graph showing the variation of doping concentration of a first doping element with doping depth;
fig. 4 is a schematic cross-sectional structure of another solar cell according to an embodiment of the disclosure;
fig. 5 is a schematic structural diagram of a photovoltaic module according to another embodiment of the present application.
Detailed Description
As known from the background art, the current solar cell has a problem of low photoelectric conversion efficiency.
Analysis has found that one of the reasons for the lower photoelectric conversion efficiency of the current solar cells is that, firstly, a diffusion process is generally adopted on the front surface of the substrate to convert part of the substrate into an emitter, and the emitter has doping ions of different types from the substrate, so that a PN junction is formed with the substrate. However, this structure will cause excessive carrier recombination in the metal pattern region on the front side of the substrate, thereby affecting the open circuit voltage and conversion efficiency of the solar cell. Second, the degree of reception of incident light is generally inconsistent for the front and back sides of the solar cell, and therefore, the performance requirements for the doped conductive layer on the front side of the solar cell and the doped conductive layer on the back side of the solar cell are inconsistent. In the current solar cell, the design of the doped conductive layer of the solar cell is not generally related to the feature of being located on the front surface or the back surface, so that the photoelectric conversion performance of the solar cell cannot be effectively improved.
The embodiment of the application provides a solar cell, the doping element concentration of a first doping conductive layer arranged on the front surface of a substrate is larger than that of a second doping conductive layer arranged on the back surface of the substrate, so that the sheet resistance of the first doping conductive layer is lower, the metal contact recombination loss of the first doping conductive layer can be improved, and the collection efficiency of carriers is improved. And, the thickness of the first doped conductive layer is set to be smaller, so that parasitic absorption of incident light rays irradiated to the front surface of the substrate by the first doped conductive layer can be reduced. The doping concentration of the second doped conductive layer is smaller, on one hand, auger recombination of the second doped conductive layer can be reduced, passivation performance of the second doped conductive layer is improved, on the other hand, the thickness of the second doped conductive layer is larger, the risk that doping elements of the second doped conductive layer diffuse into a substrate due to excessive doping elements of the second doped conductive layer and excessive thinness of the second doped conductive layer can be reduced, and further the problem that a dead layer is formed due to accumulation of the doping elements of the second doped conductive layer at an interface of the substrate can be avoided, carrier transmission efficiency is improved, and photoelectric conversion performance of the solar cell is improved.
Embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, as will be appreciated by those of ordinary skill in the art, in the various embodiments of the present application, numerous technical details have been set forth in order to provide a better understanding of the present application. However, the technical solutions claimed in the present application can be implemented without these technical details and with various changes and modifications based on the following embodiments.
Fig. 1 is a schematic cross-sectional structure of a solar cell according to an embodiment of the present disclosure.
Referring to fig. 1, a solar cell includes: a substrate 100, the substrate 100 having an opposite front surface and a back surface; a first tunneling layer 110 and a first doped conductive layer 120 on the front surface of the substrate 100 aligned with the metal pattern region and sequentially disposed in a direction away from the substrate 100, the doping element type of the first doped conductive layer 120 being the same as the doping element type of the substrate 100; the second tunneling layer 140 and the second doped conductive layer 150 are disposed on the back surface of the substrate 100 in sequence along a direction away from the substrate 100, the doping element type of the second doped conductive layer 150 is different from the doping element type of the first doped conductive layer 120, the activated doping element concentration in the first doped conductive layer 120 is greater than the activated doping element concentration in the second doped conductive layer 150, and the thickness d1 of the first doped conductive layer 120 is not greater than the thickness d2 of the second doped conductive layer 150.
It can be appreciated that the incident light received by the front surface of the substrate 100 is greater than the incident light received by the back surface of the substrate 100, and the embodiment of the application provides the first doped conductive layer 120 with a greater concentration of doping elements and a smaller thickness of the first doped conductive layer 120 for the feature that the first doped conductive layer 120 is located on the front surface of the substrate 100 and the incident light received by the front surface of the substrate 100 is greater. In this way, not only the parasitic absorption of the first doped conductive layer 120 to the incident light can be reduced, but also the sheet resistance of the first doped conductive layer 120 can be reduced, so that the metal contact recombination loss of the first doped conductive layer 120 can be improved, and the collection efficiency of carriers can be improved.
Aiming at the characteristics that the second doped conductive layer 150 is positioned on the back surface of the substrate 100 and the second doped conductive layer 150 and the substrate 100 form a back junction, the concentration of the activated doping element of the second doped conductive layer 150 is smaller, so that auger recombination of the second doped conductive layer 150 can be reduced, passivation performance of the second doped conductive layer 150 is improved, recombination of photo-generated carriers generated in a PN junction is reduced, carrier concentration is improved, and short-circuit current and open-circuit voltage are increased.
In addition, the thickness of the second doped conductive layer 150 is set to be not greater than the thickness of the first doped conductive layer 120. Specifically, in some embodiments, the thickness of the first doped conductive layer 120 may be equal to the thickness of the second doped conductive layer 150. Because the concentration of the activated doping element in the second doped conductive layer 150 is small, the doping element does not accumulate too much in the second doped conductive layer during the actual process of forming the second doped conductive layer 150, thereby avoiding the formation of too much "dead layers".
In other embodiments, the thickness of the second doped conductive layer 150 is greater than that of the first doped conductive layer 120, so that a longer doping path can be provided for the doping elements in the second doped conductive layer 150, so that the problem of formation of a "dead layer" due to accumulation of the doping elements of the second doped conductive layer 150 at the interface of the substrate 100 can be improved, the mobility of photo-generated carriers can be improved, and the problem of accumulation at the interface of the substrate 100 due to too high doping element concentration of the second doped conductive layer 150 can be further improved due to lower doping element concentration in the second doped conductive layer 150.
The substrate 100 is used to receive incident light and generate photo-generated carriers, and in some embodiments, the substrate 100 may be a silicon substrate, and the material of the silicon substrate may include at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In other embodiments, the material of the substrate 100 may also be silicon carbide, an organic material, or a multi-component compound. The multi-component compounds may include, but are not limited to, perovskite, gallium arsenide, cadmium telluride, copper indium selenium, and the like.
In some embodiments, the substrate 100 has a doping element therein, where the doping element is of an N-type or a P-type, the N-type element may be a group v element such As a phosphorus (P) element, a bismuth (Bi) element, an antimony (Sb) element, or an arsenic (As) element, and the P-type element may be a group iii element such As a boron (B) element, an aluminum (Al) element, a gallium (Ga) element, or an indium (In) element. For example, when the substrate 100 is a P-type substrate, the internal doping element type is P-type. Alternatively, when the substrate 100 is an N-type substrate, the internal doping element type is N-type.
Both the front and back sides of the substrate 100 may be configured to receive incident light or reflected light. In some embodiments, the front surface of the substrate 100 may be configured as a pyramid-shaped textured surface, so that the front surface of the substrate 100 has a smaller reflectivity for incident light, and thus has a greater absorption and utilization of light. The back surface of the substrate 100 may be configured as a non-pyramid-shaped textured surface, such as a laminated step shape, so that the second tunneling layer 140 located on the back surface of the substrate 100 has higher density and uniformity, and the second tunneling layer 140 has a good passivation effect on the back surface of the substrate 100.
The first tunneling layer 110 and the first doped conductive layer 120 on the front side of the substrate 100 are used to form a passivation contact structure on the front side of the substrate 100, the second tunneling layer 140 and the second doped conductive layer 150 on the back side of the substrate 100 are used to form a passivation contact structure on the back side of the substrate 100, and passivation contact structures are disposed on the front side and the back side of the substrate 100, so that the solar cell forms a double-sided TOPCON (Tunnel Oxide Passivated Contact, tunneling oxide passivation contact) cell. In this way, the passivation contact structures on the front and back sides of the substrate 100 can play a role in reducing carrier recombination on both the front and back sides of the substrate 100, and compared with the passivation contact structure formed on only one surface of the substrate 100, carrier loss of the solar cell is greatly reduced, so that open-circuit voltage and short-circuit current of the solar cell are improved. In this embodiment, the first tunneling layer 110 and the first doped conductive layer 120 are disposed only on the front surface of the substrate 100 aligned with the metal pattern region, so that parasitic absorption of the first doped conductive layer 120 on incident light can be reduced, and absorption and utilization rate of the non-metal alignment region on the incident light can be improved.
By forming the passivation contact structure, recombination of carriers on the surface of the substrate 100 can be reduced, thereby increasing an open-circuit voltage of the solar cell and improving photoelectric conversion efficiency of the solar cell. In some embodiments, the material of the first tunneling layer 110 and the second tunneling layer 140 may be a dielectric material, for example, any one of silicon oxide, magnesium fluoride, silicon oxide, amorphous silicon, polysilicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide.
The first doped conductive layer 120 and the second doped conductive layer 150 are used for performing a field passivation effect, specifically, by forming a built-in electric field at the interface of the substrate 100 to reduce the concentration of electrons or holes at the interface of the substrate 100, thereby achieving a surface passivation effect.
In the actual process of preparing the first doped conductive layer 120 and the second doped conductive layer 150, a diffusion process is required to be performed on the first doped conductive layer 120 and the second doped conductive layer 150. In an actual diffusion process, a problem may occur in that the concentration of the doping element is too high to exceed the maximum solid solubility of the first doped conductive layer 120, the second doped conductive layer 150 or the substrate 100, which may lead to the generation of a so-called "dead layer". The existence of the dead layer can cause lattice defects, so that part of doped elements are precipitated and cannot be used as donor impurities, and the lattice mismatch and dislocation can cause compound centers, so that the problem of lower minority carrier lifetime is caused.
In this embodiment, the entire second doped conductive layer 150 is disposed on the back surface of the substrate 100, so that the area of the formed PN junction is larger. In order to reduce recombination of photo-generated carriers generated at the PN junction on the back surface of the substrate 100 to increase the concentration of carriers, it is necessary to avoid the problem of "dead layers" generated at the interface of the substrate 100 as much as possible, thereby preventing the problem that lattice defects caused by the "dead layers" become recombination centers. Based on this, the thickness of the second doped conductive layer 150 is set to be larger, so that a longer doping path can be provided for the doping element in the second doped conductive layer 150, thereby improving the problem that the doping element of the second doped conductive layer 150 is accumulated at the interface of the substrate 100 to form a "dead layer", and improving the mobility of the photo-generated carriers. Also, the concentration of the doping element in the second doped conductive layer 150 is set to be low, so that the problem of formation of a pile-up at the interface of the substrate 100 due to the excessively high concentration of the doping element of the second doped conductive layer 150 can be further improved.
Since the front surface of the substrate 100 receives more incident light, in order to reduce absorption of the incident light by the front surface of the substrate 100, the first doped conductive layer 120 is only disposed on the front surface of the substrate 100 aligned with the metal pattern region, so that parasitic absorption of the incident light by the first doped conductive layer 120 can be reduced, and the photoelectric conversion performance of the solar cell is improved as a whole while improving the utilization rate of the incident light by the front surface of the substrate 100 and the mobility of carriers on the back surface of the substrate 100. In some embodiments, the metal pattern region is defined as an electrode region.
In some embodiments, the thickness d1 of the first doped conductive layer 120 is 20nm to 300nm, for example, 20nm to 50nm, 50nm to 80nm, 80nm to 130nm, 130nm to 150nm, 130nm to 180nm, 180nm to 230nm, 230nm to 260nm, or 260nm to 300nm. In this range, the thickness of the first doped conductive layer 120 is smaller, so that parasitic absorption of the first doped conductive layer 120 on incident light can be further reduced, and the utilization rate of the solar cell on the incident light can be improved. In addition, because the thickness of the first doped conductive layer 120 is smaller, after the diffusion process is performed on the first doped conductive layer 120, diffusion elements in the first doped conductive layer 120 are concentrated, and the concentration of carriers of the first doped conductive layer 120 can be increased, so that the sheet resistance of the first doped conductive layer 120 is lower, the metal contact recombination loss of the first doped conductive layer 120 can be reduced, and the collection capability of the carriers is improved. On the other hand, in this range, the thickness of the first doped conductive layer 120 is not too small, so that the first doped conductive layer 120 forms a strong electrostatic field on the front surface of the substrate 100, so that the field passivation effect of the first doped conductive layer 120 is significantly improved.
In some embodiments, the first doped conductive layer includes a first doping element, where the first doping element is activated by annealing to obtain an activated first doping element, and an activation rate of the first doping element in the first doped conductive layer 120 is 40% -80%, for example, 40% -45%, 45% -50%, 50% -55%, 55% -60%, 60% -65%, 65% -70%, 70% -75%, or 75% -80%. In some embodiments, the activation rate may be obtained by dividing the concentration of the activated doping element by the concentration of the total implanted doping element. The doping element will not work until after activation, and the non-activated doping element will form a "dead layer". The activation rate of the first doping element is related to the thickness of the first doped conductive layer 120 and the concentration of the total implanted doping element in the first doped conductive layer 120. Based on the thickness of the first doped conductive layer 120 being 20 nm-300 nm, the activation rate of the first doped element in the first doped conductive layer 120 is set to be 40% -80%, so that the concentration distribution of the activated first doped element in the first doped conductive layer 120 in the thickness direction of the first doped conductive layer 120 meets expectations, the sheet resistance of the first doped conductive layer 120 is low, and meanwhile, a good field passivation effect of the first doped conductive layer 120 on the substrate 100 is maintained, and therefore carrier recombination on the front surface of the substrate 100 can be reduced.
Specifically, in some embodiments, in the direction in which the first doped conductive layer 120 points to the substrate 100, the concentration of the activated first doping element in the first doped conductive layer 120 gradually decreases, that is, a concentration gradient pointing to the substrate 100 is formed in the first doped conductive layer 120, so that the first doped conductive layer 120 is beneficial to form an electrostatic field pointing to the substrate 100 on the front surface of the substrate 100, so as to increase the concentration of carriers on the front surface of the substrate 100, and perform a surface passivation function.
In some embodiments, the activated first doping element concentration is 1×10 20 atom/cm 3 ～6×10 20 atom/cm 3 For example, it may be 1X 10 20 atom/cm 3 ～2×10 20 atom/cm 3 、2×10 20 atom/cm 3 ～3×10 20 atom/cm 3 、3×10 20 atom/cm 3 ～4×10 20 atom/cm 3 、4×10 20 atom/cm 3 ～5×10 20 atom/cm 3 Or 5X 10 20 atom/cm 3 ～6×10 20 atom/cm 3 . Within this range, the concentration of the activated first doping element in the first doped conductive layer 120 is relatively high, so that the first doped rewind tape forms a relatively strong electrostatic field on the front surface of the substrate 100, which is beneficial to enhance the field passivation of the first doped conductive layer 120Is used. On the other hand, in this range, the sheet resistance of the first doped conductive layer 120 can be made smaller, which is favorable for favoring the metal contact recombination loss which can only be achieved by the small first doping rewinding, so that the collection efficiency of carriers can be improved. On the other hand, in this range, the concentration of the activated first doping element in the first doped conductive layer 120 is made not to be too high, so that the concentration of the first doping element implanted in the first doped conductive layer 120 is made not to be too high in the process of actually forming the first doped conductive layer 120, and the problem that the activation rate of the first doping element is lowered due to the too high concentration of the implanted first doping element, so that the probability of forming the "dead layer" is high can be prevented. In addition, the concentration of the activated first doping element is not too high, so that the problem that the first doping conductive layer 120 generates stronger auger recombination due to the too high concentration of the doping element in the first doping conductive layer 120 can be prevented, and the good passivation performance of the first doping conductive layer 120 can be maintained.
In some embodiments, the ratio of the width of each first doped conductive layer 120 to the width of the substrate 100 is 0.0001 to 0.0012, for example, may be 0.0001 to 0.0002, 0.0002 to 0.0004, 0.0004 to 0.0006, 0.0006 to 0.0008, 0.0008 to 0.0010, or 0.0010 to 0.0012. Each first doped conductive layer 120 is disposed corresponding to the metal pattern region, so that the width of the first doped conductive layer 120 is much smaller than that of the substrate 100 in this range, thereby greatly reducing the parasitic absorption of the first doped conductive layer 120 to the incident light, and greatly improving the utilization rate of the substrate 100 to the incident light. On the other hand, in this range, the width of the first doped conductive layer 120 is not too small compared with the substrate 100, so that the fermi level difference between the first doped conductive layer 120 and the substrate 100 is ensured, and therefore, energy band bending is formed on the front surface of the substrate 100 aligned to the metal pattern region, so as to effectively block the passage of minority carriers, and not to affect the transmission of majority carriers, realize the selective collection of carriers, and further enhance the collection capability of carriers. Based on this, in some embodiments, the first doped conductive layer may be provided with a width of 20 μm to 200 μm, for example, 20 μm to 40 μm, 40 μm to 65 μm, 65 μm to 85 μm, 85 μm to 100 μm, 100 μm to 130 μm, 130 μm to 150 μm, 150 μm to 180 μm, or 180 μm to 200 μm.
In some embodiments, the area ratio of the first doped conductive layer on the front surface of the substrate 100 is 0.01 to 0.15. The area ratio of the first doped conductive layer 120 on the front surface of the substrate 100 referred to herein refers to the ratio of the total area of the first doped conductive layer 120 on the front surface of the substrate 100 in all metal pattern areas to the area of the substrate 100. Within this range, the first doped conductive layer 120 can be ensured to have a good field passivation effect, and parasitic absorption of incident light irradiated to the front surface of the substrate 100 by the first doped conductive layer 120 can be reduced.
In some embodiments, the thickness d2 of the second doped conductive layer 150 is 50nm to 500nm, for example, can be 50nm to 100nm, 100nm to 150nm, 150nm to 200nm, 200nm to 250nm, 250nm to 300nm, 350nm to 400nm, 400nm to 450nm, or 450nm to 500nm. In addition, in this range, the thickness of the second doped conductive layer 150 is made larger than that of the first doped conductive layer 120, so that it is ensured that a longer diffusion path is provided for the doping element during the process of actually forming the second doped conductive layer 150, and the doping element located in the second doped conductive layer 150 is prevented from forming accumulation, so that the probability of generating a "dead layer" can be reduced, the recombination probability of carriers can be reduced, the number and efficiency of the transmission of photo-generated carriers generated by the second doped conductive layer 150 into the substrate 100 can be improved, and the open circuit voltage and the short circuit current can be increased. On the other hand, in this range, the thickness of the second doped conductive layer 150 is not too large, so that the problem of causing large stress on the substrate 100 due to the too large thickness of the second doped conductive layer 150 can be prevented, and the substrate 100 is ensured to have good stability.
In some embodiments, the second doped conductive layer 150 includes a second doping element that is activated by annealing. It can be appreciated that, because the thickness of the second doped conductive layer 150 is greater, a longer diffusion path is provided for the second doped element, so that, even if the concentration of the second doped element is lower, the second doped element is diffused in the second doped conductive layer 150 more uniformly and dispersedly, so that the risk of stacking the second doped element in the second doped conductive layer 150 is reduced, thereby improving the process yield of actually annealing the second doped element, reducing the generation of a "dead layer", and further improving the activation rate of the second doped element in the second doped conductive layer 150. Specifically, in some embodiments, the activation rate of the second doping element in the second doped conductive layer 150 may be 30% to 80%, for example, 30% to 35%, 35% to 40%, 40% to 50%, 50% to 55%, 55% to 60%, 60% to 65%, 65% to 70%, 70% to 75%, or 75% to 80%.
In some embodiments, the activated second doping element concentration is 4×10 19 atom/cm 3 ～9×10 19 atom/cm 3 For example, it may be 4X 10 19 atom/cm 3 ～5×10 19 atom/cm 3 、5×10 19 atom/cm 3 ～6×10 19 atom/cm 3 、6×10 19 atom/cm 3 ～7×10 19 atom/cm 3 、7×10 19 atom/cm 3 ～8×10 19 atom/cm 3 Or 8X 10 19 atom/cm 3 ～9×10 19 atom/cm 3 . In this range, the concentration of the second doping element activated in the second doped conductive layer 150 is not excessively high, so that auger recombination of the second conductive layer can be reduced, carrier recombination on the back surface of the substrate 100 can be reduced, and mobility of carriers generated by the second doped conductive layer 150 to transfer into the substrate 100 can be improved. In addition, in this range, the concentration of the second doping element injected in the second doping conductive layer 150 is also low in the process of actually forming the second doping conductive layer 150, so that the probability of forming a "dead layer" can be prevented from being increased due to formation of a pile-up in the second doping conductive layer 150 caused by the excessively high concentration of the injected second doping element, and the mobility of carriers can be further improved.
Referring to fig. 2, in some embodiments, the second doped conductive layer 150 includes: the first region and the second region are disposed near the substrate 100, the slope of the doping curve of the activated second doping element in the first region is not less than 0 in the direction along the first region toward the second region, the slope of the doping curve of the activated second doping element in the second region is less than 0, and the slope of the doping curve is the slope of the curve of the doping concentration of the activated second doping element varying with the doping depth. In some embodiments, the doping profile of the activated second doping element concentration and the total implanted second doping element concentration as a function of doping depth may be measured by electrochemical capacitance-voltage methods (ElectrochemicalCapacitance Voltage, ECV) and secondary ion mass spectrometry (Secondary Ion Mass Spectrometry, SIMS). Wherein, the mark 1 represents the doping curve of the total implanted second doping element concentration with the doping depth, and the mark 2 represents the doping curve of the activated second doping element concentration with the doping depth.
The doping profile slope of the activated second doping element in the first region is not less than 0, and may be equal to 0 or greater than 0, for example. That is, in the first region, as the doping depth increases, the doping concentration of the activated second doping element gradually increases or does not change, i.e., the doping concentration of the activated second doping element is maintained at a higher level. Specifically, in some embodiments, in the first region, the doping profile slope of the activated second doping element in the first region is equal to 0, i.e., the doping concentration of the activated second doping element is unchanged with increasing doping depth; in other embodiments, in the first region, the doping profile slope of the activated second doping element in the first region is greater than 0, i.e., the doping concentration of the activated second doping element gradually increases with increasing doping depth; in still other embodiments, in the first region, the slope of the doping curve of the activated second doping element in the first region may also trend to be greater than 0 and equal to 0, that is, the doping concentration of the activated second doping element increases gradually and then remains unchanged as the doping depth increases.
Also, as can be readily seen from fig. 2, in the first region, the concentration of the total implanted second doping element shows the same trend as the concentration of the activated second doping element with increasing doping depth, i.e. the concentration of the total implanted second doping element in the first region is also kept at a higher concentration level. This means that the activation rate of the second doping element remains high in the first region.
In the second region, the gradient of the doping curve of the activated second doping element in the first region is smaller than 0, namely, the concentration of the activated second doping element gradually decreases along with the increase of the doping depth, and in the second region, the concentration of the total injected second doping element gradually decreases along with the increase of the doping depth. Furthermore, it is not difficult to find that in the second region, the difference in concentration between the activated second doping element and the total implanted second doping element gradually increases with increasing doping depth, which means that in the second region, the activation rate of the second doping element gradually decreases with increasing doping depth. This is because the problem of accumulation in the second doped conductive layer 150 becomes serious as the diffusion depth of the second doping element increases, which leads to the generation of a "dead layer", so that the activation rate of the second doping element is lowered.
Specifically, the activation rate of the second doping element starts to decrease at the interface of the first region and the second region, which means that the "dead layer" problem starts to occur at the interface of the first region and the second region. Reference is made to fig. 2. The doping depth at the junction of the first region and the second region is approximately 130 nm.
Although the "dead layer" problem still occurs in the second doped conductive layer 150, in the embodiment of the present application, by setting the thickness of the second doped conductive layer 150 to be larger and the concentration of the doping element activated in the second doped conductive layer 150 to be lower, the concentration and thickness of the dead layer can be reduced, thereby improving the "dead layer" problem. Referring specifically to fig. 3, fig. 3 is a graph showing the variation of the doping concentration of the first doping element with the doping depth.
In this embodiment, the thickness of the second doped conductive layer 150 is set to be greater than the thickness of the first doped conductive layer 120, and the activated doping element concentration of the second doped conductive layer 150 is smaller than the activated doping element concentration in the first doped conductive layer 120. Thus, the first doped conductive layer 120 is compared to the second doped conductive layer 150. As can be readily seen from fig. 3, when the doping depth of the first doped conductive layer 120 is about 100nm, the activation rate of the first doped element starts to be greatly reduced, i.e., a "dead layer" starts to appear, whereas when the doping depth of the second doped conductive layer 150 is about 130nm, the activation rate of the second doped element starts to be reduced, referring to fig. y. It can be seen that the formation of the "dead layer" is closely related to the thickness of the doped conductive layer, and by providing the second doped conductive layer 150 with a larger thickness, a longer diffusion path is provided for the second doping element, so that the "dead layer" problem can be improved.
In some embodiments, the activated second doping element has a doping profile slope of greater than 0 in the first region, and the activated second doping element has a doping profile slope of 1 xe in the first region 16 ～1×e 19 For example, it may be 1×e 16 ～5×e 16 、5×e 16 ～1×e 17 、1×e 17 ～5×e 17 、5×e 17 ～1×e 18 、1×e 18 ～5×e 18 Or 5×e 18 ～1×e 19 . In this range, the doping concentration of the second doping element of the first region is made higher, so that the activation rate of the second doping element is kept higher. The second doped conductive layer 150 of the first region mainly plays a role of generating a larger fermi level difference with the substrate 100, so that an energy band bending effect is formed on the back surface of the substrate 100, and the passage of minority carriers is effectively blocked, so that selective transmission of carriers is realized. Furthermore, the doping profile slope of the activated second doping element in the second region is-1×e 16 ～-1×e 20 For example, -1×e 16 ～-5×e 16 、-5×e 16 ～-1×e 17 、-1×e 17 ～-5×e 17 、-5×e 17 ～-1×e 18 、-1×e 18 ～-5×e 18 、-5×e 18 ～-1×e 19 、-1×e 19 ～-5×e 19 Or-5 Xe 19 ～-1×e 20 . Within this range, the slope of the doping profile of the activated second doping element is not too small compared to the first region, so that the doping concentration of the second doping element in the second region does not drop too fast, the occupied volume of the "dead layer" in the second doped conductive layer 150 can be reduced, and the lattice of the second doped conductive layer 150 can be reducedThe defect is beneficial to reducing the recombination of photogenerated carriers and improving the carrier concentration.
In some embodiments, the concentration of the activated second doping element of the first region is 4×10 19 atom/cm 3 ～9×10 19 atom/cm 3 For example, it may be 4X 10 19 atom/cm 3 ～5×10 19 atom/cm 3 、5×10 19 atom/cm 3 ～6×10 19 atom/cm 3 、6×10 19 atom/cm 3 ～7×10 19 atom/cm 3 、7×10 19 atom/cm 3 ～8×10 19 atom/cm 3 Or 8X 10 19 atom/cm 3 ～9×10 19 atom/cm 3 . The activated second doping element of the second region has a concentration of 1×10 16 atom/cm 3 ～9×10 19 atom/cm 3 For example, it may be 1X 10 16 atom/cm 3 ～5×10 16 atom/cm 3 、5×10 16 atom/cm 3 ～1×10 17 atom/cm 3 、1×10 17 atom/cm 3 ～5×10 17 atom/cm 3 、5×10 17 atom/cm 3 ～1×10 18 atom/cm 3 、1×10 18 atom/cm 3 ～1×10 19 atom/cm 3 Or 1X 10 19 atom/cm 3 ～9×10 19 atom/cm 3 . Within this range, the concentration of the second doping element that causes the activation of the first region and the second region is made smaller than the concentration of the first doping element that is activated in the first doped conductive layer 120, so that auger recombination of the second doped conductive layer 150 can be reduced, and recombination of photogenerated carriers can be reduced. On the other hand, in this range, the concentration of the second doping element activated in the first region and the second region is not too small, so that the back junction formed by the second doped conductive layer 150 and the substrate 100 can be ensured to generate more photo-generated carriers, and the solar cell can be ensured to have better photoelectric conversion performance.
Since the activation rate of the second doping element is larger in the second doped conductive layer 150 of the first region, that is, the probability of occurrence of the "dead layer" is smaller, it is necessary to set the thickness of the first region to be larger, so that the "dead layer" problem can be improved. Based on this, in some embodiments, the thickness of the second doped conductive layer 150 of the first region is set to 50nm to 500nm, for example, 50nm to 80nm, 80nm to 120nm, 120nm to 180nm, 180nm to 250nm, 250nm to 300nm, 300nm to 350nm, 350nm to 400nm, or 400nm to 500nm, and the thickness of the second doped conductive layer 150 of the second region is set to 30nm to 300nm, for example, 30nm to 50nm, 50nm to 80nm, 80nm to 130nm, 130nm to 170nm, 170nm to 220nm, 220nm to 250nm, 250nm to 270nm, or 270nm to 300nm. Within this range, the greater thickness of the second doped conductive layer 150 of the first region may reduce the volume occupied by the "dead layer" in the second doped conductive layer 150, thereby reducing lattice defects of the second doped conductive layer 150. It is noted that in some embodiments, the total thickness of the second doped conductive layer 150 formed by the first region and the second region is kept within a range of 50nm to 500nm, regardless of the thickness of the second doped conductive layer 150 in the first region and the second region, so that the stress of the second doped conductive layer 150 on the substrate is kept small.
In some embodiments, the substrate 100 is an N-type substrate, the first doped conductive layer 120 is an N-type doped conductive layer, and the second doped conductive layer 150 is a P-type doped conductive layer.
In other embodiments, the substrate 100 may be a P-type silicon substrate, the first doped conductive layer 120 is a P-type doped conductive layer, and the second doped conductive layer 150 is an N-type doped conductive layer.
In some embodiments, when the substrate 100 is an N-type substrate, the first doped conductive layer 120 is an N-type doped conductive layer, and the second doped conductive layer 150 is a P-type doped conductive layer, the doping element of the first doped conductive layer may be phosphorus, and the doping element of the second doped conductive layer 150 may be boron.
In some embodiments, the material of the first doped conductive layer and the second doped conductive layer 150 includes at least one of amorphous silicon, microcrystalline silicon, or polysilicon.
In some embodiments, further comprising: the first passivation layer 170, a first portion of the first passivation layer 170 is located on a surface of the first doped conductive layer 120 remote from the substrate 100, and a second portion of the first passivation layer 170 is located on a front surface where the non-metal pattern regions are aligned. The first passivation layer 170 can have a good passivation effect on the front surface of the substrate 100, for example, can perform better chemical passivation on dangling bonds on the front surface of the substrate 100, reduce the defect state density on the front surface of the substrate 100, and better inhibit carrier recombination on the front surface of the substrate 100. The first passivation layer 170 of the first portion is directly contacted with the front surface of the substrate 100, so that the first tunneling layer 110 and the first doped conductive layer 120 are not disposed between the first passivation layer 170 of the first portion and the substrate 100, and thus, the parasitic absorption problem of the first doped conductive layer 120 on the incident light can be reduced.
In some embodiments, the top surface of the first portion of the first passivation layer 170 is not flush with the top surface of the second portion of the first passivation layer 170. Specifically, the top surface of the first portion of the first passivation layer 170 may be lower than the top surface of the second portion of the first passivation layer 170, so that the thickness of the first portion on the front surface of the substrate 100 is not too thick, and the problem that stress damage is generated on the front surface of the substrate 100 due to the larger thickness of the first portion is prevented, so that more interface state defects are generated on the front surface of the substrate 100 and more carrier recombination centers are generated is prevented.
In some embodiments, the first passivation layer 170 may be a single layer structure, and in other embodiments, the first passivation layer 170 may be a multi-layer structure. In some embodiments, the material of the first passivation layer 170 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.
In some embodiments, further comprising: the first electrode 160, the first electrode 160 is disposed on the metal pattern region and electrically connected to the first doped conductive layer 120. The PN junction formed on the back surface of the substrate 100 is configured to receive incident light and generate photo-generated carriers, and the generated photo-generated carriers are transmitted from the substrate 100 to the first doped conductive layer 120 and then transmitted to the first electrode 160, where the first electrode 160 is configured to collect the photo-generated carriers. Since the doping ion type of the first doped conductive layer 120 is the same as the doping ion type of the substrate 100, the metal contact recombination loss between the first electrode 160 and the first doped conductive layer 120 is reduced, and thus the carrier contact recombination between the first electrode 160 and the first doped conductive layer 120 can be reduced, and the short-circuit current and the photoelectric conversion performance of the solar cell are improved. In some embodiments, the first electrode 160 is disposed on the front side of the substrate 100 where the metal pattern region is aligned. The first electrode 160 penetrates the first passivation layer 170 to be in electrical contact with the first doped conductive layer 120.
Referring to fig. 4, in some embodiments, further comprising: the diffusion region 130, the diffusion region 130 is located in the substrate 100 aligned with the metal pattern region, the top of the diffusion region 130 is in contact with the first tunneling layer 110, and the doping element concentration of the diffusion region 130 is greater than that of the substrate 100.
The diffusion region 130 may serve as a carrier transport channel, and the diffusion region 130 is formed only in the substrate 100 aligned with the metal pattern region, so that carriers in the substrate 100 may be more easily transported into the doped conductive layer through the diffusion region 130, i.e., the diffusion region 130 functions as a carrier transport channel. In addition, since the diffusion region 130 is only disposed in the substrate 100 aligned with the metal pattern region, the carriers in the substrate 100 can be intensively transferred into the diffusion region 130 and then transferred into the first doped conductive layer 120 through the diffusion region 130, so that the concentration of the carriers in the first doped conductive layer 120 can be greatly improved. It should be noted that, in the embodiment of the present application, the diffusion region 130 is not disposed in the substrate 100 aligned with the non-metal pattern region, so that the carrier concentration of the front surface of the substrate 100 aligned with the non-metal pattern region is not too high, and the problem of serious carrier recombination on the front surface of the substrate 100 aligned with the non-metal pattern region is prevented. In addition, the carriers in the substrate 100 can be prevented from being transmitted to the front surface of the substrate 100 aligned with the non-metal pattern region, so that the problem that the carriers are excessively compounded due to the fact that the carriers are accumulated on the front surface of the substrate 100 aligned with the non-metal pattern region and a dead layer is generated on the front surface of the substrate 100 aligned with the non-metal pattern region can be avoided, and the photoelectric conversion performance of the solar cell is improved as a whole.
In some embodiments, further comprising: the second passivation layer 180, the second passivation layer 180 is located on the surface of the second doped conductive layer 150 away from the substrate 100. The second passivation layer 180 is used for performing a good passivation effect on the back surface of the substrate 100, reducing the defect state density of the back surface of the substrate 100, and well inhibiting carrier recombination on the back surface of the substrate 100. The bump structure on the back surface of the substrate 100 has a smaller degree of roughness, so that the second passivation layer 180 deposited on the back surface of the substrate 100 has a higher flatness, thereby improving passivation performance of the second passivation layer 180.
In some embodiments, the second passivation layer 180 may be a single layer structure, and in other embodiments, the second passivation layer 180 may also be a multi-layer structure. In some embodiments, the material of the second passivation layer 180 may be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.
In some embodiments, further comprising: and a second electrode 190, the second electrode 190 being located on the back surface of the substrate 100, the back electrode penetrating the second passivation layer 180 to be in electrical contact with the second doped conductive layer 150.
In the solar cell provided in the embodiment, the doping element concentration of the first doped conductive layer 120 disposed on the front side of the substrate 100 is greater than the doping element concentration of the second doped conductive layer 150 disposed on the back side of the substrate 100, so that the sheet resistance of the first doped conductive layer 120 is lower, thereby improving the metal contact recombination loss of the first doped conductive layer 120 and being beneficial to enhancing the collection efficiency of carriers. Further, the thickness of the first doped conductive layer 120 is set to be small, so that parasitic absorption of incident light irradiated to the front surface of the substrate 100 by the first doped conductive layer 120 can be reduced. The arrangement of the second doped conductive layer 150 has smaller doping concentration, which can reduce auger recombination of the second doped conductive layer 150, thereby being beneficial to improving passivation performance of the second doped conductive layer 150, and meanwhile, the arrangement of the second doped conductive layer 150 has larger thickness, which can reduce risk of diffusion of doping elements of the second doped conductive layer 150 into the substrate 100 caused by excessive doping elements of the second doped conductive layer 150 and excessive thinness of the second doped conductive layer 150, thereby avoiding the problem of formation of a dead layer due to accumulation of doping elements of the second doped conductive layer 150 at the interface of the substrate 100, improving transmission efficiency of carriers, and improving photoelectric conversion performance of the solar cell.
Accordingly, another aspect of the embodiments of the present application further provides a photovoltaic module, referring to fig. 5, the photovoltaic module includes: a cell string formed by connecting a plurality of solar cells 101 provided in the above embodiments; the packaging layer 102, the packaging layer 102 is used for covering the surface of the battery string; and a cover plate 103, wherein the cover plate 103 is used for covering the surface of the encapsulation layer 102 away from the battery strings. The solar cells 101 are electrically connected in whole or multiple pieces to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and/or parallel.
Specifically, in some embodiments, multiple battery strings may be electrically connected by conductive tape 104. The encapsulant layer 102 covers the front and back sides of the solar cell 101, and specifically, the encapsulant layer 102 may be an organic encapsulant film such as an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyethylene terephthalate (PET) film. In some embodiments, the cover 103 may be a cover 103 having a light transmitting function, such as a glass cover, a plastic cover, or the like. Specifically, the surface of the cover plate 103 facing the encapsulation layer 102 may be a concave-convex surface, thereby increasing the utilization of incident light.
While the preferred embodiment has been described, it is not intended to limit the scope of the claims, and any person skilled in the art can make several possible variations and modifications without departing from the spirit of the invention, so the scope of the invention shall be defined by the claims.
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of implementing the present application and that various changes in form and details may be made therein without departing from the spirit and scope of the present application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention shall be defined by the appended claims.
Claims (20)
1. A solar cell, comprising:
a substrate having an opposite front side and a back side;
the first tunneling layer and the first doped conductive layer are positioned on the front surface of the substrate aligned with the metal pattern area and are sequentially arranged along the direction away from the substrate, and the doping element type of the first doped conductive layer is the same as the doping element type of the substrate;
The second tunneling layer and the second doped conductive layer are positioned on the back surface of the substrate and are sequentially arranged along the direction away from the substrate, the doping element type of the second doped conductive layer is different from the doping element type of the first doped conductive layer, the activated doping element concentration in the first doped conductive layer is larger than the activated doping element concentration in the second doped conductive layer, and the thickness of the first doped conductive layer is not larger than the thickness of the second doped conductive layer.
2. The solar cell of claim 1, wherein the first doped conductive layer has a thickness of 20nm to 300nm and the second doped conductive layer has a thickness of 50nm to 500nm.
3. The solar cell according to claim 2, wherein the first doped conductive layer comprises a first doping element, the first doping element is activated by annealing to obtain an activated first doping element, and the activation rate of the first doping element in the first doped conductive layer is 40% -80%.
4. The solar cell of claim 3, wherein the activated first doping element concentration is 1 x 10 20 atom/cm 3 ～6×10 20 atom/cm 3 。
5. The solar cell of claim 4, wherein a ratio of a width of each of the first doped conductive layers to a width of the substrate is 0.0001 to 0.0012.
6. The solar cell of claim 5, wherein the first doped conductive layer has a width of 20 μιη to 200 μιη.
7. The solar cell of claim 5, wherein the first doped conductive layer has an area ratio of 0.01 to 0.15 on the front side of the substrate.
8. The solar cell according to claim 2, wherein the second doped conductive layer comprises a second doping element, the second doping element being activated by annealing, the activation rate of the second doping element in the second doped conductive layer being 30% -80%.
9. The solar cell of claim 8, wherein the activated second doping element concentration is 4 x 10 19 atom/cm 3 ～9×10 19 atom/cm 3 。
10. The solar cell of claim 8, wherein the second doped conductive layer comprises: the substrate comprises a first region and a second region, wherein the second region is arranged close to the substrate, the slope of a doping curve of the activated second doping element in the first region is not less than 0 in the direction of pointing to the second region along the first region, the slope of the doping curve of the activated second doping element in the second region is less than 0, and the slope of the doping curve is the slope of a curve of the doping concentration of the activated second doping element along with the change of doping depth.
11. The solar cell of claim 10, wherein the doping profile slope of the activated second doping element in the first region is 1 xe 16 ～1×e 19 The doping curve slope of the activated second doping element in the second region is-1×e 16 ～-1×e 20 。
12. The solar cell of claim 11, wherein the activated second doping element of the first region has a concentration of 4 x 10 19 atom/cm 3 ～9×10 19 atom/cm 3 The activated second doping element of the second region has a concentration of 1×10 16 atom/cm 3 ～9×10 19 atom/cm 3 。
13. The solar cell of claim 12, wherein the second doped conductive layer of the first region has a thickness of 50nm to 500nm and the second doped conductive layer of the second region has a thickness of 30nm to 300nm.
14. The solar cell of claim 1, 3 or 8, wherein the substrate is an N-type substrate, the first doped conductive layer is an N-type doped conductive layer, and the second doped conductive layer is a P-type doped conductive layer.
15. The solar cell of claim 14, wherein the doping element of the first doped conductive layer is a phosphorus element and the doping element of the second doped conductive layer is a boron element.
16. The solar cell of claim 15, wherein the material of the first doped conductive layer and the second doped conductive layer comprises at least one of amorphous silicon, microcrystalline silicon, or polysilicon.
17. The solar cell of claim 1, further comprising: and the first passivation layer is positioned on the surface of the first doped conductive layer far away from the substrate, and the second passivation layer is positioned on the front surface aligned with the nonmetallic pattern area.
18. The solar cell of claim 1, further comprising: and the first electrode is arranged on the metal pattern area and is electrically connected with the first doped conductive layer.
19. The solar cell of claim 1, further comprising: the diffusion region is positioned in the substrate aligned with the metal pattern region, the top of the diffusion region is in contact with the first tunneling layer, and the doping element concentration of the diffusion region is greater than that of the substrate.
20. A photovoltaic module, comprising:
a cell string formed by connecting a plurality of solar cells according to any one of claims 1 to 19;
an encapsulation layer for covering the surface of the battery string;
and the cover plate is used for covering the surface, far away from the battery strings, of the packaging layer.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211098149.9A CN117673178A (en) | 2022-09-08 | 2022-09-08 | Solar cell and photovoltaic module |
| DE202023101750.9U DE202023101750U1 (en) | 2022-09-08 | 2023-04-05 | Solar cell and photovoltaic module |
| NL2034521A NL2034521A (en) | 2022-09-08 | 2023-04-06 | Solar cell and photovoltaic module |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211098149.9A CN117673178A (en) | 2022-09-08 | 2022-09-08 | Solar cell and photovoltaic module |
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| CN117673178A true CN117673178A (en) | 2024-03-08 |
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| CN202211098149.9A Pending CN117673178A (en) | 2022-09-08 | 2022-09-08 | Solar cell and photovoltaic module |
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| CN (1) | CN117673178A (en) |
| DE (1) | DE202023101750U1 (en) |
| NL (1) | NL2034521A (en) |
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| DE202023101750U1 (en) | 2023-05-25 |
| NL2034521A (en) | 2024-03-14 |
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