Patent Description:
A solar cell can directly convert solar radiation energy into electrical energy, based on a photovoltaic effect of crystalline silicon. When photons of sunlight are absorbed by the crystalline silicon, electron-hole pairs may be generated. The electrons and holes, when arriving at a p-n junction composed of p-type crystalline silicon and n-type crystalline silicon, are respectively separated to two sides of the p-n junction by a junction electric field. When the solar cell is connected to an external load, a photocurrent current is generated, and electric energy is outputted. In actual use, solar cells are generally connected in series/parallel and then packaged together to form a photovoltaic module.

The solar cell further includes doped polysilicon, and the doped polysilicon may absorb light, which reduce the photoelectric conversion efficiency of the solar cell. In order to reduce the light absorption capability of the doped polysilicon and increase the photoelectric conversion efficiency of the solar cell, a thickness of the doped polysilicon is generally reduced. However, the thinner doped polysilicon has a large lateral transport resistance and an increased carrier recombination probability, so the reduction in the thickness of the doped polysilicon reduces the photoelectric conversion efficiency of the solar cell.

<CIT> teaches a solar cell including: a substrate, a tunneling layer formed on the back surface of the substrate, a retardation layer formed on the tunneling layer, a field passivation layer spaced apart from the tunneling layer by the retardation layer, a second passivation film formed on the field passivation layer, and a back electrode. The retardation layer prevents doped ions in the field passivation layer from migrating into the substrate.

Embodiments of the present disclosure provide a solar cell and a photovoltaic module. The solar cell has a reduced transverse resistance and increased recombination due to a thinner first doped conductive layer, thereby improving photoelectric conversion efficiency of the solar cell.

The present disclosure provide a solar cell. The solar cell includes a body and a first electrode. The body has a first region and a second region. Along a thickness direction of the solar cell, at least part of the first region covers the first electrode. The second region is a region of the body other than the first region. The body includes a substrate, a first tunneling layer, a first doped conductive layer, and a second doped conductive layer. The first tunneling layer is arranged on a side of the substrate, and the first tunneling layer has a greater thickness in the first region than in the second region. The first doped conductive layer is arranged on a surface of the first tunneling layer away from the substrate, and the first electrode is electrically connected to the first doped conductive layer. The second doped conductive layer is located on a side of the substrate adjacent to the first tunneling layer, and the second doped conductive layer has a lower thickness in the first region than in the second region. The dopant element in the second doped conductive layer is from the first doped conductive layer.

In one or more embodiments, the first tunneling layer in the first region protrudes towards the first doped conductive layer with respect to the first tunneling layer in the second region, and the second doped conductive layer in the second region protrudes towards the substrate with respect to the second doped conductive layer in the first region.

In one or more embodiments, the first tunneling layer in the first region protrudes towards the substrate with respect to the first tunneling layer in the second region, and the second doped conductive layer in the second region protrudes towards the first doped conductive layer with respect to the second doped conductive layer in the first region.

In one or more embodiments, in the second doped conductive layer, doping concentration of a dopant element in the first region is less than that in the second region.

In one or more embodiments, the doping concentration c1 of the dopant element in the first region of the second doped conductive layer satisfies: <NUM> X <NUM><NUM> atoms/cm<NUM>≤c1 ≤ <NUM> × <NUM><NUM> atoms/cm<NUM>.

In one or more embodiments, the doping concentration c2 of the dopant element in the second region of the second doped conductive layer satisfies: <NUM>×<NUM><NUM> atoms/cm<NUM>≤c2≤<NUM>×<NUM><NUM> atoms/cm<NUM>.

In one or more embodiments, a thickness H11 of the first tunneling layer in the first region satisfies: <NUM>≤H11≤<NUM>.

In one or more embodiments, a thickness H12 of the first tunneling layer in the second region satisfies: <NUM>≤H12≤<NUM>.

In one or more embodiments, a thickness H21 of the second doped conductive layer in the first region satisfies: <NUM>≤H21≤<NUM>.

In one or more embodiments, a thickness H22 of the second doped conductive layer in the second region satisfies: <NUM>≤H22≤<NUM>.

In one or more embodiments, the first region is arranged alternately with the second region along a width direction of the solar cell.

In one or more embodiments, along a width direction of the solar cell, a width D1 of the first region satisfies: <NUM>≤ D1 ≤<NUM>.

In one or more embodiments, along a width direction of the solar cell, a ratio of a width D2 of the first electrode to a width D1 of the first region satisfies: <NUM>≤D2/D1≤<NUM>.

In one or more embodiments, the body further includes an emitter arranged on a surface of the substrate away from the first tunneling layer, and the solar cell further includes a second electrode electrically connected to the emitter.

In one or more embodiments, the body further includes a first passivation layer and a second passivation layer, the first passivation layer is arranged on a side of the first doped conductive layer away from the substrate, and the second passivation layer is arranged on a side of the emitter away from the substrate.

In one or more embodiments, the body further includes: a second tunneling layer, a third doped conductive layer, and a fourth doped conductive layer. The second tunneling layer is arranged on a side of the substrate away from the first tunneling layer, and the second tunneling layer has a greater thickness in the first region than in the second region. The third doped conductive layer is arranged on a surface of the second tunneling layer away from the substrate, and the fourth doped conductive layer is located on a side of the substrate close to the second tunneling layer, and the fourth doped conductive layer has a less thickness in the first region than in the second region.

The solar cell further includes a third electrode electrically connected to the third doped conductive layer.

In one or more embodiments, the body further includes a first passivation layer and a third passivation layer, the first passivation layer is arranged on a side of the first doped conductive layer away from the substrate, and the third passivation layer is arranged on a side of the third doped conductive layer away from the substrate.

Some embodiments of the present disclosure provide a photovoltaic module. The photovoltaic module includes: a solar cell string, an encapsulation layer, and a cover plate. The solar cell string includes a plurality of solar cells connected to one another, the encapsulation layer covers a surface of the solar cell string, and the cover plate covers a surface of the packaging layer away from the solar cell string.

The solar cell includes a body and a first electrode. The body has a first region and a second region. Along a thickness direction of the solar cell, at least part of the first region covers the first electrode. The second region is a region of the body other than the first region. The body includes a substrate, a first tunneling layer, a first doped conductive layer, and a second doped conductive layer. The first tunneling layer is arranged on a side of the substrate, and the first tunneling layer has a greater thickness in the first region than in the second region. The first doped conductive layer is arranged on a surface of the first tunneling layer away from the substrate, and the first electrode is electrically connected to the first doped conductive layer. The second doped conductive layer is located on a side of the substrate adjacent to the first tunneling layer, and the second doped conductive layer has a less thickness in the first region than in the second region.

It should be understood that the foregoing general description and the following detailed description are exemplary only and are not intended to limit the present disclosure.

The accompanying drawings herein are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the specification, serve to explain the principles of the present disclosure.

In order to better understand the technical solutions of the present disclosure, embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

It is to be made clear that the described embodiments are only some rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts fall within the protection scope of the present disclosure.

The terms used in the embodiments of the present disclosure are intended only to describe particular embodiments and are not intended to limit the present disclosure. As used in the embodiments of the present disclosure and the appended claims, the singular forms of "a/an", "the", and "said" are intended to include plural forms, unless otherwise clearly specified by the context.

It is to be understood that the term "and/or" used herein is merely an association relationship describing associated objects, indicating that three relationships may exist. For example, A and/or B indicates that there are three cases of A alone, A and B together, and B alone. In addition, the character "/" herein generally means that the associated objects are in an "or" relationship.

It is to be noted that the location terms such as "above", "below", "left", and "right" described in the embodiments of the present disclosure are described with reference to the angles shown in the accompanying drawings, and should not be construed as limitations on the embodiments of the present disclosure. In addition, in the context, it is to be further understood that, when one element is referred to as being connected "above" or "below" another element, the one element may be directly connected "above" or "below" another element, or connected "above" or "below" another element via an intermediate element.

Embodiments of the present disclosure provide a solar cell. As shown in <FIG>, the solar cell includes a body and a first electrode <NUM>. The body has a first region I and a second region II. Along a thickness direction X of the solar cell, at least part of the first region I covers the first electrode <NUM>. The thickness direction X of the solar cell is a direction perpendicular to the solar cell. The second region II is a region of the body other than the first region I. The body includes: a substrate <NUM>, a first tunneling layer <NUM>, a first doped conductive layer <NUM>, and a second doped conductive layer <NUM>. The first tunneling layer <NUM> is arranged on a side of the substrate <NUM>, and a thickness of the first tunneling layer <NUM> in the first region I is greater than that in the second region II. The first doped conductive layer <NUM> is arranged on a surface of the first tunneling layer <NUM> away from the substrate <NUM>, and the first electrode <NUM> is electrically connected to the first doped conductive layer <NUM>. As shown in <FIG>, the first electrode <NUM> is in contact with the first doped conductive layer <NUM>. The second doped conductive layer <NUM> is located on a side of the substrate <NUM> adjacent to the first tunneling layer <NUM>, and a thickness of the second doped conductive layer <NUM> in the first region I is less than that in the second region II.

In this embodiment, as shown in <FIG>, the first tunneling layer <NUM> is a tunneling layer for majority carriers, and at the same time chemically passivates the substrate <NUM> to reduce interface states. The first doped conductive layer <NUM> can form energy band bending, realize selective transport of the carriers, and reduce recombination losses of the carriers. The first electrode <NUM> is electrically connected to the first doped conductive layer <NUM>, and is not in contact with the first tunneling layer <NUM>, thereby maintaining good interface passivation. A small part of the dopant element in the first doped conductive layer <NUM> may enter the substrate <NUM> by passing through the first tunneling layer <NUM>, and form the second doped conductive layer <NUM> on a surface of the substrate <NUM>. Since the thickness of the first tunneling layer <NUM> in the first region I is different from that in the second region II, the thickness of the second doped conductive layer <NUM> on the surface of the substrate <NUM> formed by the dopant element from the first doped conductive layer <NUM> is different.

As shown in <FIG>, the thickness of the first tunneling layer <NUM> in the first region I is greater than that in the second region II, so that the thickness of the second doped conductive layer <NUM> in the first region I is less than that in the second region II. In the first region I, the first electrode <NUM> extends into the first doped conductive layer <NUM>, which damages a structure of the first doped conductive layer <NUM> and increases recombination of carriers. A thicker first tunneling layer <NUM> is arranged on a side of the first electrode <NUM> adjacent to the substrate <NUM>, which can improve a passivation effect of the first region, reduce the thickness of the second doped conductive layer <NUM>, reduce the recombination of the carriers, and improve the photoelectric conversion efficiency of the solar cell. In the second region II, a thinner first tunneling layer <NUM> improves transport capability of the carriers from the substrate <NUM> to the first doped conductive layer <NUM>, and makes the second doped conductive layer <NUM> thicker. As a result, the sheet resistance of the second doped conductive layer <NUM> is reduced, the transverse transport capability of the carriers in the second doped conductive layer <NUM> is improved, and the photoelectric conversion efficiency of the solar cell is improved.

For example, the substrate <NUM> may be a crystalline semiconductor (e.g., crystalline silicon) containing a dopant element. The dopant element may be an N-type dopant element such as a Group V element including phosphorus (P), arsenic (As), bismuth (Bi), and antimony (Sb), or a P-type dopant element such as a Group III element including boron (B), aluminum (Al), gallium (Ga), and indium (In). In one or more embodiments, the first tunneling layer <NUM> is a silicon oxide layer (SiOx), with a thickness ranging from <NUM> to <NUM>. The thickness of the first tunneling layer <NUM> may be, for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. A material of the first electrode <NUM> includes at least one conductive metal material such as silver, aluminum, copper, nickel, or the like.

In addition, the photoelectric conversion efficiency of the solar cell may include a photoelectric conversion efficiency at a front surface of the solar cell and a photoelectric conversion efficiency at a back surface of the solar cell. In addition, a bifaciality of the solar cell may refer to a ratio of the photoelectric conversion efficiency at the back surface of the solar cell to the photoelectric conversion efficiency at the front surface of the solar cell. If the first doped conductive layer <NUM> is thicker, the first doped conductive layer <NUM> absorbs more light energy, and fewer light is received by the substrate <NUM>, which affects the photoelectric conversion efficiency at the back surface of the solar cell and reduces the bifaciality of the solar cell. At the same time, if the first doped conductive layer <NUM> is thicker, the front efficiency of the solar cell can also be reduced.

In one or more embodiments, as shown in <FIG>, the first tunneling layer <NUM> in the first region I protrudes towards the first doped conductive layer <NUM> with respect to the first tunneling layer <NUM> in the second region II, and the second doped conductive layer <NUM> in the second region II protrudes towards the substrate <NUM> with respect to the second doped conductive layer <NUM> in the first region I.

In one or more embodiments, as shown in <FIG>, the first tunneling layer <NUM> in the first region I protrudes towards the substrate <NUM> with respect to the first tunneling layer <NUM> in the second region II, and the second doped conductive layer <NUM> in the second region II protrudes towards the first doped conductive layer <NUM> with respect to the second doped conductive layer <NUM> in the first region I.

As shown in <FIG>, in one or more embodiments, the first tunneling layer <NUM> in the first region I protrudes towards the first doped conductive layer <NUM> with respect to the first tunneling layer <NUM> in the second region II, so that the second doped conductive layer <NUM> in the second region II protrudes towards the substrate <NUM> with respect to the second doped conductive layer <NUM> in the first region I. That is, an interface between the first tunneling layer <NUM> and the second doped conductive layer <NUM> is a substantially flat plane.

As shown in <FIG>, in one or more embodiments, the first tunneling layer <NUM> in the first region I protrudes towards the substrate <NUM> with respect to the first tunneling layer <NUM> in the second region II, so that the second doped conductive layer <NUM> in the second region II protrudes towards the first doped conductive layer <NUM> with respect to the second doped conductive layer <NUM> in the first region I. That is, an interface between the first tunneling layer <NUM> and the first doped conductive layer <NUM> is a substantially flat plane, and a surface of the second doped conductive layer <NUM> away from the first tunneling layer <NUM> is a substantially flat plane.

In one or more embodiments, in the second doped conductive layer <NUM>, a doping concentration of a dopant element in the first region I is less than that in the second region II.

In this embodiment, if the doping concentration of the dopant element in the second doped conductive layer <NUM> in the first region I is smaller, recombination of the carriers caused by the influence of the first electrode <NUM> on the body can be reduced. If the doping concentration of the dopant element in the second doped conductive layer <NUM> in the second region II is greater, resistance of the body can be reduced, and the transverse transport capability of the carriers can be improved, thereby improving the photoelectric conversion efficiency of the solar cell.

The dopant element in the second doped conductive layer <NUM> is from the first doped conductive layer <NUM>, so the dopant element in the second doped conductive layer <NUM> is the same as the dopant element in the first doped conductive layer <NUM>. The first doped conductive layer <NUM> may be amorphous silicon, microcrystalline silicon, polycrystalline silicon, or the like including the dopant element. The dopant element may be an N-type dopant element such as a Group V element including P, As, Bi, and Sb, or a P-type dopant element such as a Group III element including B, Al, Ga, and In. Moreover, the first doped conductive layer <NUM> and the substrate <NUM> are doped with a same type of dopant element.

In one or more embodiments, the doping concentration c1 of the dopant element of the second doped conductive layer <NUM> in the first region I satisfies: <NUM>×<NUM><NUM> atoms/cm<NUM>≤c1≤<NUM>×<NUM><NUM> atoms/cm<NUM>. For example, the doping concentration c1 may be <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, or the like.

In this embodiment, the doping concentration c1 of the dopant element of the second doped conductive layer 14in the first region I should not be excessively large or excessively small. If the doping concentration c1 is excessively large (e.g., greater than <NUM>×<NUM><NUM> atoms/cm<NUM>), recombination of the carriers of the second doped conductive layer <NUM> in the first region I increases, so that the efficiency of the solar cell cannot be effectively improved. If the doping concentration c1 is excessively small (e.g., less than <NUM>×<NUM><NUM> atoms/cm<NUM>), the second doped conductive layer <NUM> cannot provide enough carriers, thereby affecting the efficiency of the solar cell. Therefore, when the doping concentration c1 of the dopant element of the second doped conductive layer <NUM> in the first region I satisfies: <NUM>×<NUM><NUM> atoms/cm<NUM>≤c1≤<NUM>×<NUM><NUM> atoms/cm<NUM>, the efficiency of the solar cell can be effectively improved.

In one or more embodiments, the doping concentration c2 of the dopant element of the second doped conductive layer <NUM> in the second region II satisfies: <NUM>×<NUM><NUM> atoms/cm<NUM>≤c2≤<NUM>×<NUM><NUM> atoms/cm<NUM>. For example, the doping concentration c2 may be <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, <NUM>×<NUM><NUM> atoms/cm<NUM>, or the like.

In this embodiment, the doping concentration c2 of the dopant element of the second doped conductive layer <NUM> in the second region II should not be excessively large or excessively small. If the doping concentration c2 is excessively large (e.g., greater than <NUM>×<NUM><NUM> atoms/cm<NUM>), recombination of the carriers in the second region II of the second doped conductive layer <NUM> increases, so that the efficiency of the solar cell cannot be effectively improved. If the doping concentration c2 is excessively small (e.g., less than <NUM>×<NUM><NUM> atoms/cm<NUM>), the second doped conductive layer <NUM> cannot provide enough carriers, thereby affecting the efficiency of the solar cell. Therefore, when the doping concentration c2 of the dopant element of the second doped conductive layer <NUM> in the second region II satisfies: <NUM>×<NUM><NUM> atoms/cm<NUM>≤c2≤<NUM>×<NUM><NUM> atoms/cm<NUM>, the efficiency of the solar cell can be effectively improved.

In one or more embodiments, a thickness H11 of the first tunneling layer <NUM> in the first region I satisfies: <NUM>≤H11≤<NUM>. For example, the thickness H11 may be <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In this embodiment, the thickness H11 of the first tunneling layer <NUM> in the first region I should not be excessively large or excessively small. If the thickness H11 is excessively large (e.g., greater than <NUM>), a tunneling probability of the carriers in the substrate <NUM> passing through the first tunneling layer <NUM> is reduced, which affects the efficiency of the solar cell. If the thickness H11 is excessively small (e.g., less than <NUM>), the difficulty for the dopant element in the first doped conductive layer <NUM> to pass through the first tunneling layer <NUM> is reduced, so that the thickness of the second doped conductive layer <NUM> in the first region I increases, and the recombination of the carriers increases, thereby affecting the efficiency of the solar cell. Therefore, when the thickness H11 of the first tunneling layer <NUM> in the first region I satisfies: <NUM>≤H11≤<NUM>, the efficiency of the solar cell can be effectively improved.

In one or more embodiments, a thickness H12 of the first tunneling layer <NUM> in the second region II satisfies: <NUM>≤H12≤<NUM>. For example, the thickness H12 may be <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In this embodiment, the thickness H12 of the first tunneling layer <NUM> in the second region II should not be excessively large or excessively small. If the thickness H12 is excessively large (e.g., greater than <NUM>), the difficulty for the dopant element in the first doped conductive layer <NUM> to pass through the first tunneling layer <NUM> is increased, so that the thickness of the second doped conductive layer <NUM> in the second region II decreases, and the resistance of the second doped conductive layer <NUM> increases, which affects the transverse transport capability of the carriers. If the thickness H12 is excessively small (e.g., less than <NUM>), the first tunneling layer <NUM> has a poor passivation effect on the substrate <NUM>, and the recombination of the carriers increases, thereby affecting the efficiency of the solar cell. Therefore, when the thickness H12 of the first tunneling layer <NUM> in the second region II satisfies: <NUM>≤H12≤<NUM>, the efficiency of the solar cell can be effectively improved.

In one or more embodiments, a thickness H21 of the second doped conductive layer <NUM> in the first region I satisfies: <NUM>≤H21≤<NUM>. For example, the thickness H21 may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In this embodiment, the thickness H21 of the second doped conductive layer <NUM> in the first region I should not be excessively large. If the thickness H21 is excessively large (e.g., greater than <NUM>), recombination of the carriers in the region increases, which affects the efficiency of the solar cell. In addition, the solar cell may not include the second doped conductive layer <NUM>.

In one or more embodiments, as shown in the figure, a thickness H22 of the second doped conductive layer <NUM> in the second region II satisfies: <NUM>≤H22≤<NUM>. For example, the thickness H22 may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In this embodiment, the thickness H22 of the second doped conductive layer <NUM> in the second region II should not be excessively large. If the thickness H22 is excessively large (e.g., greater than <NUM>), recombination of the carriers in the region may also increase, which affects the efficiency of the solar cell.

<FIG> is a plan view of a solar cell according to some embodiments of the present disclosure. As shown in <FIG> and <FIG>, the body has multiple first regions I and multiple second regions II, and the first regions I are arranged alternately with the second regions II along a width direction Y of the solar cell.

In this embodiment, the first region I and the second region II are spaced apart along the width direction Y of the solar cell, so that the first region I corresponds to the first electrode <NUM>, thereby effectively reducing an increase in the carrier recombination caused by damages of the first doped conductive layer <NUM> caused by the first electrode <NUM> and ensuring the efficiency of the solar cell.

In one or more embodiments, as shown in <FIG>, along the width direction Y of the solar cell, a width D1 of the first region I satisfies: <NUM>≤D1≤<NUM>. For example, the width D1 may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. <FIG> also shows the length direction Z of the solar cell, and the second electrode <NUM> extends along the length direction Z.

In this embodiment, along the width direction Y of the solar cell, the width D1 of the first region I should not be excessively large or excessively small. If the width D1 is excessively large (e.g., greater than <NUM>), the width of the second region II is excessively small, which affects the transverse transport capability of the solar cell. If the width D1 is excessively small (e.g., less than <NUM>), the first region I cannot completely cover the first electrode <NUM> along a thickness direction X of the solar cell, so that the recombination of the carriers cannot be effectively reduced, which affects the efficiency of the solar cell.

In one or more embodiments, along the width direction Y of the solar cell, a ratio of a width D2 of the first electrode <NUM> to a width D1 of the first region I satisfies: <NUM>≤D2/D1≤<NUM>. For example, the ratio of the width D2 to the width D1 may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like.

In this embodiment, along the width direction Y of the solar cell, the ratio of the width D2 of the first electrode <NUM> to the width D1 of the first region I should not be excessively large or excessively small. If the ratio of the width D2 to the width D1 is excessively large (e.g., greater than <NUM>), the first region I cannot completely cover the first electrode <NUM> along the thickness direction X of the solar cell, so that the recombination of the carriers cannot be effectively reduced, which affects the efficiency of the solar cell. If the ratio of the width D2 to the width D1 is excessively small (e.g., less than <NUM>), the width D1 of the first region I is excessively large, and the width of the second region II is excessively small, which affects the transverse transport capability of the solar cell. Therefore, when, along the width direction Y of the solar cell, the ratio of a width D2 of the first electrode <NUM> to the width D1 of the first region I satisfies: <NUM>≤D2/D1≤<NUM>, the transport capability of the solar cell can be ensured.

In one or more embodiments, as shown in <FIG> and <FIG>, the body further includes an emitter <NUM> arranged on a surface of the substrate <NUM> away from the first tunneling layer <NUM>, and the solar cell further includes a second electrode <NUM> electrically connected to the emitter <NUM>.

In this embodiment, as shown in <FIG> and <FIG>, the substrate <NUM> and the emitter <NUM> can jointly form a PN junction structure. The substrate <NUM> may be a P-type silicon substrate, the emitter <NUM> may be an N-type emitter, and the P-type silicon substrate and the N-type emitter may jointly form a built-in electric field of the PN junction. In some other embodiments, the substrate <NUM> may be an N-type silicon substrate, while the emitter <NUM> may be a P-type emitter.

In one or more embodiments, as shown in <FIG> and <FIG>, the body further includes a first passivation layer <NUM> and a second passivation layer <NUM>, the first passivation layer <NUM> is arranged on a side of the first doped conductive layer <NUM> away from the substrate <NUM>, and the second passivation layer <NUM> is arranged on a side of the emitter <NUM> away from the substrate <NUM>.

In this embodiment, as shown in <FIG> and <FIG>, the first passivation layer <NUM> can passivate a surface of the first doped conductive layer <NUM> away from the substrate <NUM>, and the second passivation layer <NUM> can passivate a surface of the emitter <NUM> away from the substrate <NUM>, thereby reducing a recombination rate of the carriers of the first doped conductive layer <NUM> and a recombination rate of the carriers of the emitter <NUM> respectively, and improving the photoelectric conversion efficiency of the solar cell.

For example, each of the first passivation layer <NUM> and the second passivation layer <NUM> may be a single layer such as a silicon oxide layer, a silicon nitride layer, an aluminum oxide layer, and a silicon oxynitride layer. For another example, each of the first passivation layer <NUM> and the second passivation layer <NUM> may be a stacked structure including at least one or more of a silicon oxide layer, a silicon nitride layer, an aluminum oxide layer, and a silicon oxynitride layer.

In one or more embodiments, as shown in <FIG> and <FIG>, the body further includes: a second tunneling layer <NUM>', a third doped conductive layer <NUM>', and a fourth doped conductive layer <NUM>'. The second tunneling layer <NUM>' is arranged on a side of the substrate <NUM> away from the first tunneling layer <NUM>, and a thickness of the second tunneling layer <NUM>' in the first region I is greater than that in the second region II. The third doped conductive layer <NUM>' is arranged on a surface of the second tunneling layer <NUM>' away from the substrate <NUM>. The fourth doped conductive layer <NUM>' is located on a side of the substrate <NUM> adjacent to the second tunneling layer <NUM>', and a thickness of the fourth doped conductive layer <NUM>' in the first region I is less than that in the second region II. The solar cell further includes a third electrode <NUM>', and the third electrode <NUM>' is electrically connected to the third doped conductive layer <NUM>'.

In this embodiment, as shown in <FIG> and <FIG>, the second tunneling layer <NUM>' is a tunneling layer for majority carriers, and at the same time chemically passivates the substrate <NUM> to reduce interface states. The third doped conductive layer <NUM>' can form energy band bending, realize selective transport of the carriers, and reduce recombination losses of the carriers. The third electrode <NUM>' is electrically connected to the third doped conductive layer <NUM>', and is not in contact with the second tunneling layer <NUM>', thereby maintaining good interface passivation. A small part of the dopant element in the third doped conductive layer <NUM>' may enter the substrate <NUM> through the second tunneling layer <NUM>', and form the fourth doped conductive layer <NUM>' on a surface of the substrate <NUM>. The thickness of the second tunneling layer <NUM>' in the first region I is different from that in the second region II, so that the thickness of the fourth doped conductive layer <NUM>' formed on the surface of the substrate <NUM> and formed by the dopant element from the third doped conductive layer <NUM>' is different.

As shown in <FIG>, the thickness of the second tunneling layer <NUM>' in the first region I is greater than that in the second region II, so that the thickness of the fourth doped conductive layer <NUM>' in the first region I is less than that in the second region II. In the first region I, the third electrode <NUM>' extends into the third doped conductive layer <NUM>', which damages a structure of the third doped conductive layer <NUM>' and increases carrier recombination. A thicker second tunneling layer <NUM>' is arranged on a side of the third electrode <NUM>' adjacent to the substrate <NUM>, which can improve a passivation effect of the region, reduce the thickness of the fourth doped conductive layer <NUM>', reduce the carrier recombination, and improve the photoelectric conversion efficiency of the solar cell. In the second region II, the thinner second tunneling layer <NUM>' improves transport capability of the carriers from the substrate <NUM> to the third doped conductive layer <NUM>', and makes the fourth doped conductive layer <NUM>' thicker, which reduces sheet resistance of the fourth doped conductive layer <NUM>', improves the transverse transport capability of the carriers, and improves the photoelectric conversion efficiency of the solar cell. For example, the second tunneling layer <NUM>' is a silicon oxide layer (SiOx), with a thickness ranging from <NUM> to <NUM>. For example, the thickness of the second tunneling layer <NUM>' may be <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or the like. The third doped conductive layer <NUM>' may be amorphous silicon, microcrystalline silicon, polycrystalline silicon, or the like containing a dopant element. The dopant element may be an N-type dopant element such as a Group V element including P, As, Bi, and Sb, or a P-type dopant element such as a Group III element including B, Al, Ga, and In. Moreover, the third doped conductive layer <NUM>' and the substrate <NUM> should be doped with different types of dopant elements, so that the third doped conductive layer <NUM>' and the substrate <NUM> together form a built-in electric field structure that functions as a PN junction.

In one or more embodiments, as shown in <FIG> and <FIG>, the body further includes a first passivation layer <NUM> and a third passivation layer <NUM>', the first passivation layer <NUM> is arranged on a side of the first doped conductive layer <NUM> away from the substrate <NUM>, and the third passivation layer <NUM>' is arranged on a side of the third doped conductive layer <NUM>' away from the substrate <NUM>.

In this embodiment, as shown in <FIG> and <FIG>, the first passivation layer <NUM> can passivate a surface of the first doped conductive layer <NUM> away from the substrate <NUM>, thereby reducing a recombination rate of the carriers of the first doped conductive layer <NUM>, and improving the photoelectric conversion efficiency of the solar cell. The third passivation layer <NUM>' can passivate a surface of the third doped conductive layer <NUM>' away from the substrate <NUM>, thereby reducing a recombination rate of the carriers of the third doped conductive layer <NUM>', and improving the photoelectric conversion efficiency of the solar cell.

For example, each of the first passivation layer <NUM> and the third passivation layer <NUM>' may be a single layer such as a silicon oxide layer, a silicon nitride layer, an aluminum oxide layer, and a silicon oxynitride layer. For another example, each of the first passivation layer <NUM> and the third passivation layer <NUM>' may be a stacked structure including at least one or more of a silicon oxide layer, a silicon nitride layer, an aluminum oxide layer, and a silicon oxynitride layer.

In one or more embodiments, as shown in <FIG>, the second tunneling layer <NUM>' in the first region I protrudes towards the third doped conductive layer <NUM>' with respect to the second tunneling layer <NUM>' in the second region II; and the fourth doped conductive layer <NUM>' in the second region II protrudes towards the substrate <NUM> with respect to the fourth doped conductive layer <NUM>' in the first region I.

In one or more embodiments, as shown in <FIG>, the second tunneling layer <NUM>' in the first region I protrudes towards the substrate <NUM> with respect to the second tunneling layer <NUM>' in the second region II; and the fourth doped conductive layer <NUM>' in the second region II protrudes towards the third doped conductive layer <NUM>' with respect to the fourth doped conductive layer <NUM>' in the first region I.

As shown in <FIG>, in one or more embodiments, the second tunneling layer <NUM>' in the first region I protrudes towards the third doped conductive layer <NUM>' with respect to the second tunneling layer <NUM>' in the second region II, so that the fourth doped conductive layer <NUM>' in the second region II protrudes towards the substrate <NUM> with respect to the fourth doped conductive layer <NUM>' in the first region I. That is, an interface between the second tunneling layer <NUM>' and the fourth doped conductive layer <NUM>' is a substantially flat plane.

As shown in <FIG>, in one or more embodiments, the second tunneling layer <NUM>' in the first region I protrudes towards the substrate <NUM> with respect to the second tunneling layer <NUM>' in the second region II, so that the fourth doped conductive layer <NUM>' in the second region II protrudes towards the third doped conductive layer <NUM>' with respect to the fourth doped conductive layer <NUM>' in the first region I. That is, an interface between the second tunneling layer <NUM>' and the third doped conductive layer <NUM>' is a substantially flat plane, and a surface of the fourth doped conductive layer <NUM>' away from the second tunneling layer <NUM>' is a substantially flat plane.

Some embodiments of the present disclosure provide a photovoltaic module. As shown in <FIG>, the photovoltaic module includes: a solar cell string <NUM>, an encapsulation layer <NUM>, and a cover plate <NUM>. The solar cell string <NUM> includes a plurality of solar cells connected to one another. The encapsulation layer <NUM> is configured to cover a surface of the solar cell string <NUM>. As shown in <FIG>, the encapsulation layer <NUM> covers at least the top and bottom surfaces of the solar cell string <NUM>. The cover plate <NUM> is configured to cover a surface of the encapsulation layer <NUM> away from the solar cell string <NUM>.

In this embodiment, as shown in <FIG>, the plurality of solar cells in the solar cell string <NUM> are electrically connected in series and/or in parallel. The cover plate <NUM>, the encapsulation layer <NUM>, and the solar cell string <NUM> may be laminated in a certain order through a lamination process to obtain a laminated assembly, and then a frame may be mounted on the laminated assembly to form the photovoltaic module, which is easy to transport and use.

Claim 1:
A solar cell comprising: a body and a first electrode (<NUM>), the body having a first region (I) and a second region (II), wherein along a thickness direction (X) of the solar cell, at least part of the first region (I) covers the first electrode (<NUM>), and the second region (II) is a region of the body other than the first region (I),
wherein the body comprises:
a substrate (<NUM>);
a first tunneling layer (<NUM>) arranged on a side of the substrate (<NUM>), wherein the first tunneling layer (<NUM>) has a greater thickness in the first region (I) than in the second region (II); and
a first doped conductive layer (<NUM>) arranged on a surface of the first tunneling layer (<NUM>) away from the substrate (<NUM>), and electrically connected to the first electrode (<NUM>);
characterized in that,
the body further comprises a second doped conductive layer (<NUM>) arranged on a side of the substrate (<NUM>) adjacent to the first tunneling layer (<NUM>), wherein a dopant element in the second doped conductive layer (<NUM>) is from the first doped conductive layer (<NUM>), and the second doped conductive layer (<NUM>) has a lower thickness in the first region (I) than that in the second region (II).