Passivated contact solar cell and photovoltaic module

Abstract

The utility model relates to the technical field of solar cells, in particular to a passivation contact solar cell and a photovoltaic module. The passivation contact solar cell comprises a silicon substrate, a dielectric layer, a first doped polycrystalline silicon layer and a second doped polycrystalline silicon layer. The dielectric layer is arranged on the silicon substrate, and the density of the dielectric layer is greater than or equal to 2.2 g / cm < 3 >. And the first doped polycrystalline silicon layer is arranged on one surface, deviating from the silicon substrate, of the dielectric layer. The second doped polycrystalline silicon layer is arranged on the surface, deviating from the dielectric layer, of the doped polycrystalline silicon layer, and the forbidden bandwidth of the second doped polycrystalline silicon layer is larger than that of the doped polycrystalline silicon layer. The second doped polycrystalline silicon layer is used for improving parasitic absorption of a long wave band, and higher photo-generated current can be obtained by reducing parasitic absorption of light of the long wave band. The more compact dielectric layer is used for preventing elements doped in the doped polycrystalline silicon layer from being pushed towards the silicon substrate, so that auger recombination is reduced, and the conversion efficiency of the passivation contact solar cell is further improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a passivated contact solar cell and a photovoltaic component. Background Art

[0002] The passivation contact structure of the passivation contact solar cell includes a dielectric layer and a doped polysilicon layer disposed on the side of the dielectric layer away from the silicon substrate. The bandgap width of the doped polysilicon layer is small, its optical transmittance is poor, and parasitic absorption is serious, which in turn affects the conversion efficiency of the solar cell. In addition, the elements doped in the doped polysilicon layer are pushed toward the silicon substrate during annealing, resulting in severe Auger recombination of the silicon substrate, which is also the reason for the reduction of the conversion efficiency of the solar cell. Utility Model Content

[0003] In order to solve the above technical problems, the present application discloses a passivated contact solar cell and a photovoltaic module. The passivated contact solar cell improves the parasitic absorption in the long-wave band by setting the second doped polysilicon layer on the side of the first doped polysilicon layer away from the dielectric layer. The parasitic absorption of long-wave band light is reduced to obtain a higher photogenerated current. The passivated contact solar cell sets a denser dielectric layer to block the elements doped in the first doped polysilicon layer from advancing toward the silicon substrate, thereby reducing Auger recombination and further improving the conversion efficiency of the passivated contact solar cell.

[0004] In a first aspect, an embodiment of the present application provides a passivated contact solar cell, comprising:

[0005] Silicon substrate;

[0006] A dielectric layer, the dielectric layer is arranged on the silicon substrate, and the density of the dielectric layer is greater than or equal to 2.2 g / cm 3 ;

[0007] a first doped polysilicon layer having a first doping element, wherein the first doped polysilicon layer is disposed on a side of the dielectric layer facing away from the silicon substrate; and

[0008] A second doped polysilicon layer having a second doping element, wherein the second doped polysilicon layer is arranged on a side of the first doped polysilicon layer away from the dielectric layer, the first doping element is different from the second doping element, and the bandgap width of the second doped polysilicon layer is greater than the bandgap width of the first doped polysilicon layer.

[0009] Optionally, the bandgap width of the second doped polysilicon layer is 2.2 eV to 3.8 eV, and the bandgap width of the first doped polysilicon layer is 1.1 eV to 1.7 eV.

[0010] Optionally, the second doping element is carbon;

[0011] And / or, the thickness of the second doped polysilicon layer is 15 nm to 25 nm.

[0012] Optionally, the dielectric layer is arranged on the backlight surface of the silicon substrate, and the conductivity type of the first doped polysilicon layer is the same as the conductivity type of the silicon substrate;

[0013] The passivated contact solar cell also includes:

[0014] An emitter, wherein the emitter is arranged on the light receiving surface of the silicon substrate;

[0015] a first functional film, the first functional film being disposed on a side of the emitter facing away from the silicon substrate; and

[0016] A first electrode penetrates the first functional film and is in ohmic contact with the emitter.

[0017] Optionally, the first functional film includes a first anti-reflection film;

[0018] The total thickness of the first anti-reflection film is 70nm to 80nm;

[0019] And / or, the refractive index of the first anti-reflection film is 2.05-2.15.

[0020] Optionally, the first anti-reflection film includes a first anti-reflection sublayer and a second anti-reflection sublayer alternately arranged away from the silicon substrate, the refractive index of the first anti-reflection sublayer is greater than the refractive index of the second anti-reflection sublayer, and the difference between the refractive index of the first anti-reflection sublayer and the adjacent second anti-reflection sublayer is not less than 0.15.

[0021] Optionally, the number of the first anti-reflection sublayer and the number of the second anti-reflection sublayer are both three;

[0022] The first anti-reflection sublayer of the first layer is arranged on the side of the emitter away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the first layer is 2.27-2.29, and the thickness of the first anti-reflection sublayer of the first layer is 14nm-16nm;

[0023] The first layer of the second anti-reflection sublayer is disposed on a surface of the first layer of the first anti-reflection sublayer away from the silicon substrate, the refractive index of the first layer of the second anti-reflection sublayer is 2.04-2.06, and the thickness of the first layer of the second anti-reflection sublayer is 14nm-16nm;

[0024] The first anti-reflection sublayer of the second layer is arranged on a surface of the second anti-reflection sublayer of the first layer away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the second layer is 2.19-2.21, and the thickness of the first anti-reflection sublayer of the second layer is 9nm-11nm;

[0025] The second anti-reflection sublayer of the second layer is arranged on a surface of the second anti-reflection sublayer of the second layer away from the silicon substrate, the refractive index of the second anti-reflection sublayer of the second layer is 2.04-2.06, and the thickness of the second anti-reflection sublayer of the second layer is 14nm-16nm;

[0026] The first anti-reflection sublayer of the third layer is arranged on a surface of the second anti-reflection sublayer of the second layer away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the third layer is 2.19-2.21, and the thickness of the first anti-reflection sublayer of the third layer is 9nm-11nm;

[0027] The third layer of the second anti-reflection sublayer is arranged on a surface of the third layer of the first anti-reflection sublayer away from the silicon substrate, the refractive index of the third layer of the second anti-reflection sublayer is 1.99-2.01, and the thickness of the third layer of the second anti-reflection sublayer is 9nm-11nm;

[0028] And / or, each of the first anti-reflection sub-layers and each of the second anti-reflection sub-layers are silicon nitride layers;

[0029] And / or, the first functional film further includes an aluminum oxide passivation film, and the aluminum oxide passivation film and the first anti-reflection film are stacked in sequence away from the silicon substrate.

[0030] Optionally, the passivated contact solar cell further comprises:

[0031] a second functional film, the second functional film being disposed on a side of the second doped polysilicon layer facing away from the first doped polysilicon layer; and

[0032] The second electrode penetrates the second functional film and the second doped polysilicon layer and is in ohmic contact with the first doped polysilicon layer.

[0033] Optionally, the silicon substrate is an N-type silicon substrate;

[0034] And / or, the dielectric layer is a silicon oxide layer;

[0035] And / or, the thickness of the dielectric layer is 0.1 nm to 5 nm;

[0036] And / or, the first doped polysilicon layer is an N-type doped polysilicon layer.

[0037] In a second aspect, an embodiment of the present application provides a photovoltaic module, comprising a passivated contact solar cell as described in the first aspect.

[0038] Compared with the prior art, the beneficial effects of the utility model are:

[0039] The embodiment of the present application provides a passivated contact solar cell, which improves the parasitic absorption in the long-wave band by arranging the second doped polysilicon layer on the side of the first doped polysilicon layer away from the dielectric layer. The parasitic absorption of light in the long-wave band is reduced to obtain a higher photogenerated current. The passivated contact solar cell is provided with a denser dielectric layer to block the elements doped in the first doped polysilicon layer from advancing toward the silicon substrate, thereby reducing Auger recombination and further improving the conversion efficiency of the passivated contact solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 It is a schematic diagram of the structure of a passivated contact solar cell provided in an embodiment of the present application.

[0042] Description of reference numerals:

[0043] 100, passivated contact solar cell; 110, silicon substrate; 111, light-receiving surface; 112, backlight surface; 120, dielectric layer; 130, first doped polysilicon layer; 140, second doped polysilicon layer; 150, emitter; 160, first functional film; 161, aluminum oxide passivation film; 162, first anti-reflection film; 1621, first layer of first anti-reflection sublayer; 1622, first layer of second anti-reflection sublayer; 1623, second layer of first anti-reflection sublayer; 1624, second layer of second anti-reflection sublayer; 1625, third layer of first anti-reflection sublayer; 1626, third layer of second anti-reflection sublayer; 170, first electrode; 180, second functional film; 190, second electrode. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0045] In the present invention, the term "on" is used to indicate a certain dependency or connection relationship. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0046] In addition, the term "disposition" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements or components. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0047] In addition, the terms "first", "second", etc. are mainly used to distinguish different devices, elements or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance and quantity of the indicated devices, elements or components. Unless otherwise specified, "plurality" means two or more.

[0048] In the related art, the passivated contact solar cell has a small bandgap width of the doped polysilicon layer, which results in poor optical transmittance and severe parasitic absorption, thus affecting the conversion efficiency of the solar cell. In addition, the elements doped in the doped polysilicon layer are pushed toward the silicon substrate during annealing, resulting in severe Auger recombination of the silicon substrate, which also affects the conversion efficiency.

[0049] To solve the above problems, the related technology sets a wide bandgap material layer between the dielectric layer and the doped polysilicon layer. The wide bandgap material layer can reduce the light parasitic absorption of the doped polysilicon layer. The wide bandgap material layer also has the function of blocking the diffusion of elements to the silicon substrate to reduce Auger recombination. Since the larger the bandgap, the more difficult it is for electrons to be excited from the valence band to the conduction band, the lower the intrinsic carrier concentration and the lower the conductivity. The wide bandgap material layer is set between the tunneling layer and the doped polysilicon layer, which will affect the current transmission between the dielectric layer and the doped polysilicon layer, and thus affect the performance of the solar cell.

[0050] Based on the above analysis, the embodiment of the present application provides a passivated contact solar cell, which improves the parasitic absorption in the long-wave band by setting the second doped polysilicon layer on the side of the first doped polysilicon layer away from the dielectric layer. The parasitic absorption of light in the long-wave band is reduced to obtain a higher photogenerated current. The passivated contact solar cell sets a denser dielectric layer to block the elements doped in the first doped polysilicon layer from advancing toward the silicon substrate, thereby reducing Auger recombination and further improving the conversion efficiency of the passivated contact solar cell.

[0051] The first aspect, such as Figure 1As shown, the embodiment of the present application provides a passivated contact solar cell 100, including a silicon substrate 110, a dielectric layer 120, a first doped polysilicon layer 130 having a first doping element, and a second doped polysilicon layer 140 having a second doping element. The first doping element is different from the second doping element.

[0052] The dielectric layer 120 is disposed on the silicon substrate 110, and the density of the dielectric layer 120 is greater than or equal to 2.2 g / cm 3 Includes any value within this density range, such as 2.2 g / cm 3 , 2.3g / cm 3 or 2.5g / cm 3 In the related art, the dielectric layer 120 with the required density is obtained by selecting the dielectric layer 120 deposited with different radio frequency powers.

[0053] The first doped polysilicon layer 130 is disposed on the side of the dielectric layer 120 facing away from the silicon substrate 110, and the conductivity type of the first doped polysilicon layer 130 is the same as or opposite to the conductivity type of the silicon substrate 110. Exemplarily, the silicon substrate 110 may be N-type or P-type, and the first doped polysilicon layer 130 may be N-type or P-type. In one embodiment, the silicon substrate 110 is an N-type silicon substrate, and the first doped polysilicon layer 130 is an N-type doped polysilicon layer, that is, the first doping element may be phosphorus.

[0054] The second doped polysilicon layer 140 is disposed on a surface of the first doped polysilicon layer 130 away from the dielectric layer 120 . The bandgap width of the second doped polysilicon layer 140 is greater than the bandgap width of the first doped polysilicon layer 130 .

[0055] The passivated contact solar cell 100 prevents the second doped polysilicon layer 140 with a larger bandgap from affecting the current transmission between the first doped polysilicon layer 130 and the dielectric layer 120 by disposing the second doped polysilicon layer 140 on the side of the first doped polysilicon layer 130 away from the dielectric layer 120. The second doped polysilicon layer 140 improves the parasitic absorption of the passivated contact solar cell 100 in the long-wave band to generate a higher photocurrent.

[0056] The second doped polysilicon layer 140 is disposed on the side of the first doped polysilicon layer 130 away from the dielectric layer 120, and the second doped polysilicon layer 140 can no longer be used to block the elements doped by the first doped polysilicon layer 130 from diffusing into the silicon substrate 110. To this end, the present application increases the density of the dielectric layer 120 to be greater than or equal to 2.2 g / cm 3 Compared with the density of the dielectric layer in the related art, which is less than 2.2g / cm 3The dielectric layer 120 of the present application is more compact, so that the dielectric layer 120 has an improved barrier capability for doping elements, thereby reducing the Auger recombination phenomenon.

[0057] Optionally, the bandgap width of the second doped polysilicon layer 140 is 2.2eV to 3.8eV, including any value within the bandgap width range, for example, 2.2eV, 3.0eV or 3.8eV, and the bandgap width of the first doped polysilicon layer 130 is 1.1eV to 1.7eV, including any value within the bandgap width range, for example, 1.1eV, 1.5eV or 1.7eV.

[0058] In some embodiments, the second doping element is carbon, that is, the second doped polysilicon layer 140 is a carbon-doped polysilicon layer. Compared with the first doped polysilicon layer 130, the carbon-doped polysilicon layer has a larger bandgap to reduce parasitic absorption in the long wavelength band.

[0059] Optionally, the second doped polysilicon layer 140 has a thickness of 15 nm to 25 nm, including any value within the thickness range, for example, 15 nm, 20 nm or 25 nm.

[0060] In the present application, the material of the dielectric layer 120 may include a variety of dielectric materials, such as at least one of silicon oxide, magnesium fluoride, amorphous silicon, polycrystalline silicon, silicon carbide, silicon nitride, silicon oxynitride, aluminum oxide, or titanium oxide. Specifically, the dielectric layer 120 may be composed of a silicon oxide layer containing silicon oxide. This is because the silicon oxide layer has excellent passivation properties, can minimize the recombination loss of minority carriers on the surface of the semiconductor substrate, and is a film with excellent durability to subsequent high-temperature processes.

[0061] The dielectric layer 120, as a barrier for electrons and holes, can be combined with the first doped polysilicon layer 130 to prevent minority carriers from passing through. The dielectric layer 120 can also have a pinhole channel effect, allowing the carriers in the solar cell to move freely, and selective passage of majority carriers is generated through the first doped polysilicon layer 130, which is conducive to reducing the recombination loss of minority carriers. In addition, the dielectric layer 120 can be used as a diffusion barrier to prevent the dopant of the first doped polysilicon layer 130 from diffusing into the silicon substrate 110.

[0062] Preferably, the dielectric layer 120 is a silicon oxide layer. In order to better provide interface passivation for the silicon substrate 110, the dielectric layer 120 has a thickness of 0.1 nm to 5 nm, including any value within the thickness range, such as 0.1 nm, 2 nm or 5 nm.

[0063] In some embodiments, the dielectric layer 120 is disposed on the backlight surface 112 of the silicon substrate 110. Accordingly, the first doped polysilicon layer 130 and the second doped polysilicon layer 140 are also located on one side of the backlight surface 112. The conductivity type of the first doped polysilicon layer 130 is the same as the conductivity type of the silicon substrate 110. The dielectric layer 120 and the first doped polysilicon layer 130 constitute a passivation contact structure of the passivation contact solar cell 100 on the backlight surface 112.

[0064] Furthermore, the passivated contact solar cell 100 further includes an emitter 150, a first functional film 160 and a first electrode 170, wherein the emitter 150 is disposed on the light-receiving surface 111 of the silicon substrate 110. The emitter 150 is preferably a PN junction formed by high-temperature diffusion, or a PN junction formed by annealing an in-situ doped amorphous silicon layer, or a PN junction formed by substitutional diffusion of an intrinsic amorphous silicon layer.

[0065] The first functional film 160 is disposed on the side of the emitter 150 facing away from the silicon substrate 110. The first functional film 160 may be at least one of the second doped polysilicon layer 140, the anti-reflection layer, or the passivation and anti-reflection layer. The first electrode 170 penetrates the first functional film 160 and makes ohmic contact with the emitter 150 to realize the current transmission function.

[0066] In some embodiments, the first functional film 160 includes a first anti-reflection film 162. Further, in order to improve the passivation effect, the first functional film 160 also includes an aluminum oxide passivation film 161. The aluminum oxide passivation film 161 and the first anti-reflection film 162 are stacked in sequence away from the silicon substrate 110.

[0067] Optionally, the total thickness of the first anti-reflection film 162 is 70 nm to 80 nm, including any value within the thickness range, for example, 70 nm, 75 nm or 80 nm.

[0068] The refractive index of the first anti-reflection film 162 is 2.05-2.15, including any point value within the refractive index range, for example, 2.05, 2.1 or 2.15.

[0069] In some embodiments, the first anti-reflection film 162 includes a first anti-reflection sublayer and a second anti-reflection sublayer alternately disposed away from the silicon substrate 110, the refractive index of the first anti-reflection sublayer is greater than the refractive index of the second anti-reflection sublayer, and the difference between the refractive index of the first anti-reflection sublayer and the refractive index of the adjacent second anti-reflection sublayer is not less than 0.15.

[0070] Optionally, the material of the first anti-reflection sublayer and the second anti-reflection sublayer may be any one of silicon oxynitride, silicon oxide or silicon nitride. Preferably, each of the first anti-reflection sublayers and each of the second anti-reflection sublayers are silicon nitride layers.

[0071] Furthermore, the number of the first anti-reflection sub-layer and the second anti-reflection sub-layer are both three;

[0072] The first first anti-reflection sublayer 1621 is disposed on the side of the emitter 150 facing away from the silicon substrate 110. The refractive index of the first first anti-reflection sublayer 1621 is 2.27-2.29, including any value within the refractive index range, such as 2.27, 2.28 or 2.29. The thickness of the first first anti-reflection sublayer 1621 is 14 nm-16 nm, including any value within the thickness range, such as 14 nm, 15 nm or 16 nm.

[0073] The first second anti-reflection sublayer 1622 is disposed on a surface of the first first anti-reflection sublayer 1621 facing away from the silicon substrate 110, the refractive index of the first second anti-reflection sublayer 1622 is 2.04-2.06 including any value within the refractive index range, for example, 2.04, 2.05 or 2.06, and the thickness of the first second anti-reflection sublayer 1622 is 14nm-16nm including any value within the thickness range, for example, 14nm, 15nm or 16nm;

[0074] The second first anti-reflection sublayer 1623 is disposed on the side of the first second anti-reflection sublayer 1622 facing away from the silicon substrate 110. The refractive index of the second first anti-reflection sublayer 1623 is 2.19-2.21, including any value within the refractive index range, such as 2.19, 2.20 or 2.21. The thickness of the second first anti-reflection sublayer 1623 is 9 nm-11 nm, including any value within the thickness range, such as 9 nm, 10 nm or 11 nm.

[0075] The second second anti-reflection sublayer 1624 is disposed on the side of the second first anti-reflection sublayer 1623 facing away from the silicon substrate 110. The refractive index of the second second anti-reflection sublayer 1624 is 2.04-2.06, including any value within the refractive index range, such as 2.04, 2.05 or 2.06. The thickness of the second second anti-reflection sublayer 1624 is 14 nm-16 nm, including any value within the thickness range, such as 14 nm, 15 nm or 16 nm.

[0076] The third first anti-reflection sublayer 1625 is disposed on the side of the second second anti-reflection sublayer 1624 facing away from the silicon substrate 110. The refractive index of the third first anti-reflection sublayer 1625 is 2.19-2.21, including any value within the refractive index range, such as 2.19, 2.20 or 2.21. The thickness of the third first anti-reflection sublayer 1625 is 9 nm-11 nm, including any value within the thickness range, such as 9 nm, 10 nm or 11 nm.

[0077] The third second anti-reflection sublayer 1626 is arranged on the side of the third first anti-reflection sublayer 1625 facing away from the silicon substrate 110, the refractive index of the third second anti-reflection sublayer 1626 is 1.99-2.01, including any value within the refractive index range, for example, 1.99, 2.00 or 2.01, and the thickness of the third second anti-reflection sublayer 1626 is 9nm-11nm, including any value within the thickness range, for example, 9nm, 10nm or 11nm.

[0078] In the present application, the first anti-reflection film 162 located on the light-receiving surface 111 adopts a high-low alternating refractive index structure between film layers, that is, the refractive index of the first anti-reflection sublayer is greater than the refractive index of the second anti-reflection sublayer and the two are arranged alternately. By selecting the difference in refractive index between adjacent first anti-reflection sublayers and second anti-reflection sublayers, the reflectivity of the first anti-reflection film 162 on the light-receiving surface 111 is reduced, thereby improving the utilization rate of short-wavelength light.

[0079] The first anti-reflection film 162 combined with the second doped polysilicon layer 140 located on the backlight surface 112 improves the parasitic absorption in the long-wave band. The passivated contact solar cell 100 improves the utilization of both long-wave and short-wave light, thereby improving the performance of the passivated contact solar cell 100.

[0080] The passivation contact solar cell 100 further includes a second functional film 180 and a second electrode 190. The second functional film 180 is disposed on a surface of the second doped polysilicon layer 140 away from the first doped polysilicon layer 130. Optionally, the second functional film 180 can be any one of the second doped polysilicon layer 140, an anti-reflection layer, or a passivation and anti-reflection layer. The second electrode 190 penetrates the second functional film 180 and the second doped polysilicon layer 140 to make ohmic contact with the first doped polysilicon layer 130 to achieve a current transmission function.

[0081] In a second aspect, an embodiment of the present application provides a photovoltaic module, comprising the passivated contact solar cell 100 as described in the first aspect.

[0082] The technical solution of the utility model will be described below in conjunction with embodiments and drawings.

[0083] Example 1

[0084] The present embodiment provides a passivated contact solar cell, including a silicon substrate, a dielectric layer, a first doped polysilicon layer and a second doped polysilicon layer. The silicon substrate is an N-type silicon substrate, the dielectric layer is a silicon oxide layer, the thickness of the dielectric layer is 1.5nm, and the first doped polysilicon layer is a phosphorus-doped N-type doped polysilicon layer. The second doped polysilicon layer is a carbon-doped polysilicon layer. The bandgap width of the second doped polysilicon layer is 3eV. The thickness of the second doped polysilicon layer is 20nm. The bandgap width of the first doped polysilicon layer is 1.2eV.

[0085] The silicon substrate has a light-receiving surface and a backlight surface. The dielectric layer is arranged on the backlight surface. The density of the dielectric layer is 2.2 g / cm 3 The first doped polysilicon layer is disposed on a side of the dielectric layer away from the silicon substrate. The second doped polysilicon layer is disposed on a side of the first doped polysilicon layer away from the dielectric layer.

[0086] The passivation contact solar cell also includes an emitter, a first functional film and a first electrode, wherein the emitter is arranged on the light receiving surface. The emitter is a boron diffusion layer, the first functional film is arranged on the side of the emitter away from the silicon substrate, and the first electrode penetrates the first functional film and makes ohmic contact with the emitter. The first functional film includes an aluminum oxide passivation film and a first anti-reflection film stacked in sequence away from the silicon substrate.

[0087] The total thickness of the first anti-reflection film is 75 nm. The refractive index of the first anti-reflection film is 2.1. The first anti-reflection film includes a first anti-reflection sublayer and a second anti-reflection sublayer alternately arranged away from the silicon substrate. Each first anti-reflection sublayer and each second anti-reflection sublayer are silicon nitride layers.

[0088] The first first anti-reflection sublayer is arranged on the side of the emitter away from the silicon substrate, the refractive index of the first first anti-reflection sublayer is 2.2, and the thickness of the first first anti-reflection sublayer is 15 nm;

[0089] The first second anti-reflection sublayer is disposed on a surface of the first first anti-reflection sublayer facing away from the silicon substrate, the refractive index of the first second anti-reflection sublayer is 2.05, and the thickness of the first second anti-reflection sublayer is 15 nm;

[0090] The second first anti-reflection sublayer is disposed on a surface of the first second anti-reflection sublayer facing away from the silicon substrate, the refractive index of the second first anti-reflection sublayer is 2.20, and the thickness of the second first anti-reflection sublayer is 10 nm;

[0091] The second second anti-reflection sublayer is disposed on a surface of the second first anti-reflection sublayer facing away from the silicon substrate, the refractive index of the second second anti-reflection sublayer is 2.05, and the thickness of the second second anti-reflection sublayer is 15 nm;

[0092] The third first anti-reflection sublayer is disposed on the side of the second second anti-reflection sublayer facing away from the silicon substrate, the refractive index of the third first anti-reflection sublayer is 2.20, and the thickness of the third first anti-reflection sublayer is 10 nm;

[0093] The third second anti-reflection sublayer is arranged on the side of the third first anti-reflection sublayer away from the silicon substrate, the refractive index of the third second anti-reflection sublayer is 2.00, and the thickness of the third second anti-reflection sublayer is 10 nm.

[0094] The passivated contact solar cell also includes a second functional film and a second electrode, wherein the second functional film is arranged on a side of the second doped polysilicon layer away from the first doped polysilicon layer, and the second functional film is a silicon nitride anti-reflection layer. The second electrode penetrates the second functional film and the second doped polysilicon layer and is in ohmic contact with the first doped polysilicon layer.

[0095] Comparative Example 1

[0096] The difference between this comparative example and Example 1 is that the passivated contact solar cell does not include a second doped polysilicon layer, and a second functional film is disposed on a side of the first doped polysilicon layer away from the dielectric layer.

[0097] The first anti-reflection film is composed of six anti-reflection sub-layers; the first to sixth anti-reflection sub-layers are stacked in sequence away from the silicon substrate;

[0098] The first anti-reflection sublayer has a thickness of 15 nm and a refractive index of 2.28;

[0099] The second anti-reflection sublayer has a thickness of 15 nm and a refractive index of 2.18;

[0100] The third anti-reflection sublayer has a thickness of 10 nm and a refractive index of 2.10;

[0101] The fourth anti-reflection sublayer has a thickness of 15 nm and a refractive index of 2.05;

[0102] The fifth anti-reflection sublayer has a thickness of 10 nm and a refractive index of 2.00;

[0103] The sixth anti-reflection sublayer has a thickness of 10 nm and a refractive index of 1.80.

[0104] The performance of the passivated contact solar cells of Example 1 and Comparative Example 1 was tested, and the results are shown in Table 1.

[0105] Table 1: Performance test results of passivated contact solar cells of Example 1 and Comparative Example 1

[0106]

[0107] The reflectivity of the light-receiving surface of the passivated contact solar cells of Example 1 and Comparative Example 1 was tested, and the test results are shown in Table 2.

[0108] Table 2: Test results of reflectivity of the light-receiving surface of the passivated contact solar cells of Example 1 and Comparative Example 1

[0109] Sample No. Example 1 Comparative Example 1 Reflectivity 0.8％ 1.2％

[0110] It can be seen from Table 1 and Table 2 that, compared with Comparative Example 1, Example 1 prevents the second doped polysilicon layer with a larger bandgap from affecting the current transmission between the first doped polysilicon layer and the dielectric layer by disposing the second doped polysilicon layer on the side of the first doped polysilicon layer away from the dielectric layer. The second doped polysilicon layer improves the parasitic absorption of the passivated contact solar cell in the long-wave band to generate higher photogenerated current, thereby making the conversion efficiency, open-circuit voltage and short-circuit current of Example 1 higher.

[0111] On the other hand, the first anti-reflection film of Example 1 adopts a high-low alternating refractive index structure between film layers, that is, the refractive index of the first anti-reflection sublayer is greater than the refractive index of the second anti-reflection sublayer and the two are arranged alternately, and the reflectivity of the first anti-reflection film on the light-receiving surface is reduced by selecting the difference in refractive index between the adjacent first anti-reflection sublayer and the second anti-reflection sublayer. According to Table 2, relative to Comparative Example 1, the reflectivity of the light-receiving surface of Example 1 is reduced to 0.8%. The reduction in the reflectivity of the light-receiving surface is beneficial to improving the utilization of short-wavelength light, thereby making the conversion efficiency, open-circuit voltage and short-circuit current of Example 1 higher.

[0112] A passivated contact solar cell and photovoltaic module disclosed in an embodiment of the utility model are introduced in detail above. Specific examples are used in this article to illustrate the principle and implementation mode of the utility model. The description of the above embodiments is only used to help understand the passivated contact solar cell and photovoltaic module of the utility model and its core idea: At the same time, for general technical personnel in this field, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the utility model.

Claims

1. A passivated contact solar cell, characterized in that: include: Silicon substrate; A dielectric layer, the dielectric layer is arranged on the silicon substrate, and the density of the dielectric layer is greater than or equal to 2.2 g / cm 3 ; A first doped polysilicon layer having a first doping element, wherein the first doped polysilicon layer is disposed on a side of the dielectric layer facing away from the silicon substrate; as well as A second doped polysilicon layer having a second doping element, wherein the second doped polysilicon layer is arranged on a side of the first doped polysilicon layer away from the dielectric layer, the first doping element is different from the second doping element, and the bandgap width of the second doped polysilicon layer is greater than the bandgap width of the first doped polysilicon layer.

2. The passivated contact solar cell according to claim 1, characterized in that: The bandgap width of the second doped polysilicon layer is 2.2 eV to 3.8 eV, and the bandgap width of the first doped polysilicon layer is 1.1 eV to 1.7 eV.

3. The passivated contact solar cell according to claim 1, characterized in that: The second doping element is carbon; And / or, the thickness of the second doped polysilicon layer is 15 nm to 25 nm.

4. The passivated contact solar cell according to claim 1, characterized in that: The dielectric layer is arranged on the backlight surface of the silicon substrate, and the conductivity type of the first doped polysilicon layer is the same as the conductivity type of the silicon substrate; The passivated contact solar cell also includes: An emitter, wherein the emitter is arranged on the light receiving surface of the silicon substrate; a first functional film, the first functional film being disposed on a side of the emitter facing away from the silicon substrate; and A first electrode penetrates the first functional film and is in ohmic contact with the emitter.

5. The passivated contact solar cell according to claim 4, characterized in that: The first functional film comprises a first anti-reflection film; The total thickness of the first anti-reflection film is 70nm to 80nm; And / or, the refractive index of the first anti-reflection film is 2.05-2.

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6. The passivated contact solar cell according to claim 5, characterized in that: The first anti-reflection film includes a first anti-reflection sublayer and a second anti-reflection sublayer alternately arranged away from the silicon substrate, the refractive index of the first anti-reflection sublayer is greater than the refractive index of the second anti-reflection sublayer, and the difference between the refractive index of the first anti-reflection sublayer and the adjacent second anti-reflection sublayer is not less than 0.

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7. The passivated contact solar cell according to claim 6, characterized in that: The number of the first anti-reflection sub-layer and the number of the second anti-reflection sub-layer are both three; The first anti-reflection sublayer of the first layer is arranged on the side of the emitter away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the first layer is 2.27-2.29, and the thickness of the first anti-reflection sublayer of the first layer is 14nm-16nm; The first layer of the second anti-reflection sublayer is disposed on a surface of the first layer of the first anti-reflection sublayer away from the silicon substrate, the refractive index of the first layer of the second anti-reflection sublayer is 2.04-2.06, and the thickness of the first layer of the second anti-reflection sublayer is 14nm-16nm; The first anti-reflection sublayer of the second layer is arranged on a surface of the second anti-reflection sublayer of the first layer away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the second layer is 2.19-2.21, and the thickness of the first anti-reflection sublayer of the second layer is 9nm-11nm; The second anti-reflection sublayer of the second layer is arranged on a surface of the second anti-reflection sublayer of the second layer away from the silicon substrate, the refractive index of the second anti-reflection sublayer of the second layer is 2.04-2.06, and the thickness of the second anti-reflection sublayer of the second layer is 14nm-16nm; The first anti-reflection sublayer of the third layer is arranged on a surface of the second anti-reflection sublayer of the second layer away from the silicon substrate, the refractive index of the first anti-reflection sublayer of the third layer is 2.19-2.21, and the thickness of the first anti-reflection sublayer of the third layer is 9nm-11nm; The third layer of the second anti-reflection sublayer is arranged on a surface of the third layer of the first anti-reflection sublayer away from the silicon substrate, the refractive index of the third layer of the second anti-reflection sublayer is 1.99-2.01, and the thickness of the third layer of the second anti-reflection sublayer is 9nm-11nm; And / or, each of the first anti-reflection sub-layers and each of the second anti-reflection sub-layers are silicon nitride layers; And / or, the first functional film further includes an aluminum oxide passivation film, and the aluminum oxide passivation film and the first anti-reflection film are stacked in sequence away from the silicon substrate.

8. The passivated contact solar cell according to any one of claims 1 to 7, characterized in that The passivated contact solar cell also includes: a second functional film, the second functional film being disposed on a side of the second doped polysilicon layer facing away from the first doped polysilicon layer; and The second electrode penetrates the second functional film and the second doped polysilicon layer and is in ohmic contact with the first doped polysilicon layer.

9. The passivated contact solar cell according to any one of claims 1 to 7, characterized in that: The silicon substrate is an N-type silicon substrate; And / or, the dielectric layer is a silicon oxide layer; And / or, the thickness of the dielectric layer is 0.1 nm to 5 nm; And / or, the first doped polysilicon layer is an N-type doped polysilicon layer.

10. A photovoltaic module, characterized in that: A solar cell comprising the passivated contact as claimed in any one of claims 1 to 9.

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