Patent Description:
With the increasing shortage of energy, the development and utilization of renewable energy is extremely urgent. Among the numerous renewable energy sources, solar energy has outstanding advantages such as no depletion risk, safety and reliability, no noise, no pollution emissions, and no limitation on distribution region of resources to its application.

Solar cells are used to convert solar energy into electrical energy, thus solar cells have been widely used. Solar cells may be classified into crystalline silicon cells and thin film cells. Among crystalline silicon cells, cells with a passivation contact structure of at least one tunneling oxide layer are widely favored because of their higher theoretical efficiency. Therefore, it is necessary to study cells with a passivation contact structure of at least one tunneling oxide layer which have better performance.

<CIT> discloses a solar cell, including: a substrate, an interface passivation layer covering a rear surface of the substrate, and an electrode located at a side of the interface passivation layer facing away from the substrate.

<CIT> discloses a solar cell, including a substrate which includes a first region and a second region, an emitter which is positioned on the upper surface of the substrate, a tunneling layer, a field passivation layer, a second passivation film and a second electrode which are sequentially stacked on the lower surface of the substrate.

<CIT> discloses a solar cell, including a semiconductor substrate, a metal electrode, a tunneling layer and a doped polycrystalline silicon layer.

<CIT> discloses a P-type tunneling oxide passivation contact solar cell, including P-type silicon, an N-type heavily doped silicon layer, a front SiNx antireflection layer, a silicon dioxide layer, an N-type heavily doped polycrystalline silicon layer, an Ag gatefinger electrode, an aluminum oxide layer and a back SiNx antireflection layer.

<CIT> discloses a solar cell preparation method, including preparing a first tunneling oxide layer on the front of a substrate and preparing a second tunneling oxide layer on the back of the substrate, growing a first polycrystalline silicon layer on the surface of a region corresponding to a front grid line in the first tunneling oxide layer, growing a second polycrystalline silicon layer on the surface of the second tunneling oxide layer, and preparing a front field on the front side of the substrate, and preparing an emitter on the back side of the substrate; growing a first anti-reflection film on the front side of the substrate, and growing a second anti-reflection film on the back side of the substrate; printing the front grid line on the front side of the substrate, and printing a back grid line on the back side of the substrate.

<CIT> discloses a solar cell, including a semiconductor substrate; a first conductive area partially positioned on a front surface of the semiconductor substrate; a second conductive area positioned on a rear surface of the semiconductor substrate; a first electrode connected to the first conductive area; and a second electrode connected to the second conductive area.

Embodiments of the present disclosure provide a solar cell and a photovoltaic module, which are at least conducive to improving performance of cells with a passivation contact structure of at least one tunneling oxide layer.

One or more embodiments are exemplarily illustrated in reference to corresponding accompanying drawing(s), and these exemplary illustrations do not constitute limitations on the embodiments. Unless otherwise stated, the accompanying drawings do not constitute scale limitations. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the existing technology, the following will briefly describe the drawings used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present disclosure. Those skilled in the art can also obtain other drawings based on these drawings without any inventive work.

It can be known from the background art that parasitic absorption of light of the existing doped conductive layer may reduce utilization rate of light of solar cells. Generally, a thickness of the doped conductive layer is reduced to address the parasitic absorption of light of the doped conductive layer. To this end, a structure of the doped conductive layer having protrusions is proposed. A relatively thick doped conductive layer is formed in a region in which the finger electrodes are formed, and a relatively thin doped conductive layer is formed in a region between adjacent finger electrodes. In this way, the parasitic absorption of light of the doped conductive layer can be reduced. However, this structure introduces new problems. For example, due to the narrow transverse transferring channel resulted from the relatively thin doped conductive layer formed in the region between adjacent finger electrodes, a large number of carriers collide and consume each other in the transferring process, thereby affecting the transferring rate of carriers.

In the embodiments of the present disclosure, at least one conductive connection structure is formed between and connected with adjacent protrusions. In this way, the carriers can be transferred through the at least one conductive connection structure in the transverse transferring process, thereby improving the transverse transferring capacity of the carriers and the doped conductive layer. Moreover, compared with the relatively thick doped conductive layer, the solar cell provided by the present disclosure can reduce parasitic absorption of light of the doped conductive layer.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Those skilled in the art should understand that, in the embodiments of the present disclosure, many technical details are provided for the reader to better understand the present disclosure. However, even without these technical details and various modifications and variants based on the following embodiments, the technical solutions claimed in the present disclosure can be realized.

<FIG> are structural schematic diagrams of the solar cell provided by embodiments of the present disclosure. <FIG> is a structural schematic diagram of a solar cell provided by some embodiments of the present disclosure. <FIG> is a sectional schematic diagram along the dotted line AA in <FIG> of the solar cell provided by some embodiments of the present disclosure. <FIG> is a top view of a first solar cell provided by some embodiments of the present disclosure. <FIG> is a top view of a second solar cell not part of the invention provided by some embodiments of the present disclosure. <FIG> is a top view of a third solar cell not part of the invention provided by some embodiments of the present disclosure. <FIG> is a top view of a fourth solar cell provided by some embodiments of the present disclosure. <FIG> is a top view of a fifth solar cell provided by some embodiments of the present disclosure.

Referring to <FIG>, the solar cell includes a substrate <NUM>, a tunneling dielectric layer <NUM>, a doped conductive layer <NUM>, at least one conductive connection structure <NUM>, a passivation layer <NUM> and a plurality of finger electrodes <NUM>. The tunneling dielectric layer <NUM> is formed on the substrate <NUM>. The doped conductive layer <NUM> is formed on the tunneling dielectric layer <NUM> and has a plurality of protrusions <NUM> arranged along a first direction X, each protrusion <NUM> of the plurality of protrusions <NUM> extends along a second direction Y perpendicular to the first direction X. The at least one conductive connection structure <NUM> is formed between two adjacent protrusions <NUM> and is connected with sidewalls of the two adjacent protrusions <NUM>. The passivation layer <NUM> is over the doped conductive layer <NUM> and the at least one conductive connection structure <NUM>. Each finger electrode <NUM> of the plurality of finger electrodes <NUM> extends along the second direction Y to penetrate the passivation layer <NUM> and connect to a respective protrusion <NUM>. By forming the at least one conductive connection structure <NUM>, carriers can be transversely transferred through the at least one conductive connection structure <NUM> between two adjacent protrusions <NUM>. In this way, transverse transferring capacity of the solar cell can be improved.

In some embodiments, the substrate <NUM> is a silicon substrate, which may include one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. In some other embodiments, the material of the substrate <NUM> may include silicon carbide, organic material or multicomponent compound. The multicomponent compound may include, but is not limited to, perovskite, gallium arsenide, cadmium telluride, copper indium selenium and the like.

In some embodiments, the substrate <NUM> has N-type or P-type doping elements. N-type elements may be Group-V elements such as phosphorus (P), bismuth (Bi), antimony (Sb) or arsenic (As), and P-type elements may be Group-III elements such as boron (B), aluminum (Al), gallium (Ga) or indium (In). For example, when the substrate <NUM> is a P-type substrate, the doping elements in the substrate are P-type elements. Alternatively, when the substrate <NUM> is an N-type substrate, the doping elements in the substrate are N-type elements.

In some embodiments, the tunneling dielectric layer <NUM> and the doped conductive layer <NUM> may form a passivation contact structure on the substrate <NUM>. The formation of the tunneling dielectric layer <NUM> and the doped conductive layer <NUM> can reduce the recombination of carriers at surface of the solar cell and increase the open-circuit voltage of the solar cell, thereby improving the efficiency of the solar cell. In some embodiments, the tunneling dielectric layer <NUM> may be formed on a first surface of the substrate <NUM>. The first surface is a light receiving surface facing sunlight. In some embodiments, the tunneling dielectric layer <NUM> may be formed on a second surface of the substrate <NUM>. The second surface is a surface opposite to the first surface and facing away sunlight. In some embodiments, the tunneling dielectric layer <NUM> may be formed on both the first surface and the second surface of the substrate <NUM> (not shown in <FIG>). It should be understood that other layers on the tunneling dielectric layer <NUM> are also formed on the first surface and/or the second surface of the substrate <NUM> at the same time.

In some embodiments, the tunneling dielectric layer <NUM> may be further configured to reduce or prevent the diffusion of doping elements in the doped conductive layer <NUM> into the substrate <NUM>.

In some embodiments, the materials of the tunneling dielectric layer <NUM> may include, but are not limited to, dielectric materials having tunneling effect such as aluminum oxide, silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, intrinsic polycrystalline silicon and the like. The tunneling dielectric layer <NUM> may be formed by a layer of oxide of silicon (SiOx), which has good passivation characteristics, and carriers can easily tunnel through the layer of oxide of silicon.

In some embodiments, a thickness of the tunneling dielectric layer <NUM> may range from <NUM> to <NUM>. In some other embodiments, the thickness of the tunneling dielectric layer <NUM> ranges from <NUM> to <NUM>. In some other embodiments, the thickness of the tunneling dielectric layer <NUM> ranges from <NUM> to <NUM>. When the thickness of the tunneling dielectric layer <NUM> is less than <NUM>, it is difficult to form the tunneling dielectric layer <NUM>. When the thickness of the tunneling dielectric layer <NUM> is greater than <NUM>, the tunneling effect is weak.

In some embodiments, the at least one conductive connection structure <NUM> and the doped conductive layer <NUM> are made of a same material. In this way, the variety of materials in the production process can be reduced to facilitate management. For example, the materials of the conductive connection structure <NUM> include at least one of polycrystalline silicon, amorphous silicon or microcrystalline silicon.

In some embodiments, the protrusions <NUM> of the doped conductive layer <NUM> and the at least one conductive connection structure <NUM> may be formed at the same time. In other words, the protrusions <NUM> and the at least one conductive connection structure <NUM> are formed by etching the doped conductive layer <NUM> in a same process operation. In this way, the connection reliability between the protrusions <NUM> and the at least one conductive connection structure <NUM> can be secured, and the number of production operations in the generating process and production time can be reduced. In some other embodiments, the protrusions and the at least one conductive connection structure may be formed separately.

In some embodiments, the material of the doped conductive layer <NUM> may be one of doped amorphous silicon, doped polycrystalline silicon or doped microcrystalline silicon. In some other embodiments, the doped conductive layer <NUM> may be made of other materials, such as silicon carbide, which may be selected according to actual situation.

In some embodiments, a conductive layer may be first formed on the tunneling dielectric layer <NUM>, and then dope the conductive layer to form the doped conductive layer <NUM>.

In some embodiments, the thickness of the doped conductive layer <NUM> ranges from <NUM> to <NUM>. In some other embodiments, the thickness of the doped conductive layer <NUM> ranges from <NUM> to <NUM>. The above-mentioned ranges of thickness of the doped conductive layer <NUM> can ensure that the optical loss of the doped conductive layer <NUM> is low and the interface passivation effect of the tunneling dielectric layer <NUM> is good, thereby improving the efficiency of the solar cell. In the embodiments of the present disclosure, the material of the doped conductive layer may be polycrystalline silicon.

In some embodiments, the doped conductive layer <NUM> and the substrate <NUM> are of a same doping type. It can be understood that when the doping type of the substrate <NUM> is N type and the doping type of the doped conductive layer <NUM> is P type, the majority carriers in the substrate <NUM> are electrons and the majority carriers in the doped conductive layer <NUM> are holes, recombination will occur between the electrons and the holes, resulting in reduction of the carriers collected by the finger electrodes <NUM>. Therefore, when the doped conductive layer <NUM> and the substrate <NUM> are of a same doping type, reduction of the carriers collected by the finger electrodes <NUM> can be prevented.

In some embodiments, the substrate <NUM> is an N-type substrate, and the doped conductive layer <NUM> is an N-type polycrystalline silicon layer. In some other embodiments, the substrate is a P-type substrate, and the doped conductive layer is a P-type polycrystalline silicon layer. The N-type substrate and N-type polycrystalline silicon layer have relatively high photoelectric conversion efficiency. The formation process of the P-type substrate and P-type polycrystalline silicon layer is simple and can be selected according to the actual situation. The embodiments of the present disclosure do not limit the substrate <NUM> and the doped conductive layer <NUM>.

In some embodiments, the conductive connection structure <NUM> and the protrusions <NUM> are formed by etching the doped conductive layer <NUM>. The shape of the doped conductive layer <NUM> may be set first, and then the doped conductive layer <NUM> is etched to form the protrusions <NUM> and the conductive connection structure <NUM> in a same process operation.

In some embodiments, the passivation layer <NUM> may be an antireflection film layer. In this way, the light reflected by the surface of the solar cell can be reduced, thereby increasing the light transmittance of the solar cell. The passivation layer <NUM> may have a single-layer structure or a stacked-layers structure, and the materials of the passivation layer <NUM> may include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, aluminum oxide or the like. In some embodiments, the passivation layer <NUM> is a hydrogen containing passivation layer, for example, the passivation layer is made of silicon oxide containing hydrogen, silicon nitride containing hydrogen, silicon oxynitride containing hydrogen and the like.

In some embodiments, the plurality of finger electrodes <NUM> is used to collect and converge the currents of the solar cell. The finger electrodes <NUM> may be obtained by sintering firing-through paste. The materials of the finger electrodes <NUM> may include one or more of aluminum, silver, gold, nickel, molybdenum or copper. In some embodiments, the finger electrodes <NUM> refer to thin grid lines or finger grid lines, which are different from the main grid lines or busbars.

Referring to <FIG>, in some embodiments, the solar cell includes a plurality of conductive connection structures <NUM> arranged at intervals along at least one of the first direction X and the second direction Y, and there is at least one finger electrode <NUM> between adjacent conductive connection structures <NUM> in the first direction X. In other words, the plurality of conductive connection structures <NUM> are arranged at intervals along the first direction X, the second direction Y or the first direction X and the second direction Y. In the first direction X, there is at least one finger electrode <NUM> between adjacent conductive connection structures <NUM>. When there is one finger electrode <NUM> between adjacent conductive connection structures <NUM>, there is one or more conductive connection structures <NUM> between every two adjacent protrusions. When there are a plurality of finger electrodes <NUM> between adjacent conductive connection structures <NUM>, the conductive connection structures <NUM> are distributed in a spaced manner. For example, in the first direction, there is one or more conductive connection structures <NUM> between a first and a second finger electrodes, but there is no conductive connection structure <NUM> between the second and a third finger electrodes. By forming at least one finger electrode <NUM> between adjacent conductive connection structures <NUM>, the transverse transferring capacity of the solar cell can be improved.

It is noted that the above-mentioned first finger electrode, second finger electrode and third finger electrode are only used to illustrate, and do not constitute a limit to the finger electrodes <NUM>.

Referring to <FIG>, in some embodiments, there is at least one conductive connection structure <NUM> between each two adjacent finger electrodes <NUM>. In other words, there is at least one conductive connection structure <NUM> between all finger electrodes <NUM> that are adjacent. In this way, the transverse transferring capacity between adjacent protrusions <NUM> can be improved.

Referring to <FIG>, in some embodiments, there is at least one conductive connection structure <NUM> between some of the adjacent finger electrodes <NUM>, there is no conductive connection structure <NUM> between some of the adjacent finger electrodes <NUM>, and in the first direction, the conductive connection structures <NUM> are arranged in a regular manner. For example, there is one or more conductive connection structures <NUM> between a first and a second finger electrodes, there is no conductive connection structure <NUM> between the second and a third finger electrodes, and there is one or more conductive connection structures <NUM> between the third and a fourth finger electrodes, and so on. Alternatively, there is one or more conductive connection structures <NUM> between the first and the second finger electrodes, there is one or more conductive connection structures <NUM> between the second and the third finger electrodes, there is no conductive connection structure <NUM> between the third and the fourth finger electrodes, and there is one or more conductive connection structures <NUM> between the fourth and a fifth finger electrodes, and so on. Alternatively, the conductive connection structures <NUM> are arranged in an irregular manner.

It is noted that the above-mentioned arrangement manners are only examples for ease of illustration, other arrangement manners also can be applied.

Referring to <FIG>, in some embodiments, there are a plurality of conductive connection structures <NUM> arranged at intervals between adjacent finger electrodes <NUM>. That is to say, there are a plurality of conductive connection structures <NUM> arranged at intervals along the second direction between adjacent finger electrodes <NUM>. In this way, the transverse transferring capacity between adjacent finger electrodes <NUM> can be improved. Compared with the case where there is only one conductive connection structure <NUM> between adjacent finger electrodes <NUM>, the more the conductive connection structures <NUM>, the stronger the transverse transferring capacity is.

In some embodiments, in the second direction Y, a distance between adjacent conductive connection structures <NUM> of the plurality of conductive connection structures <NUM> arranged at intervals is constant. In this way, it is convenient to the laser ablation process in the generating process, in other word, there is no need of adjusting the distance between adjacent conductive connection structures, thereby being convenient to the production.

In some embodiments, a distance between adjacent conductive connection structures <NUM> in the second direction ranges from <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM> or the like. When the distance between adjacent conductive connection structures <NUM> is less than <NUM>, excessively serried conductive connection structures <NUM> may cause serious light absorption, which is not conducive to improving the photoelectric conversion efficiency of the solar cell. When the distance between adjacent conductive connection structures <NUM> is greater than <NUM>, excessively few conductive connection structures <NUM> cannot provide improving effect good enough. In some other embodiments, the distance between adjacent conductive connection structures <NUM> may have other values, which may be determined according to actual situation, embodiments of the present disclosure do not limit the distance between adjacent conductive connection structures <NUM>.

Referring to <FIG>, <FIG> and <FIG>, in some embodiments, the plurality of conductive connection structures <NUM> form an array, and the array includes a plurality of columns of conductive connection structures <NUM> arranged along the first direction X and a plurality of rows of conductive connection structures <NUM> arranged along the second direction Y. In other words, the plurality of conductive connection structures <NUM> are arranged in a regular manner along the first direction X and the second direction Y. In this way, the transverse transferring capacity of the solar cell can be improved, and the production difficulty of forming the plurality of conductive connection structures <NUM> can be reduced.

Taking the solar cell including <NUM> columns of conductive connection structures <NUM> arranged along the first direction X as an example, a first, a second, a third and a fourth columns of conductive connection structures are arranged along the first direction X in sequence, and in the second direction Y, any conductive connection structure of the first column of conductive connection structures and a respective conductive connection structure of the second column of conductive connection structures, a respective conductive connection structure of the third column of conductive connection structures and a respective conductive connection structure of the fourth column of conductive connection structures are in a same row. In some other embodiments, any conductive connection structure of the first column of conductive connection structures and a respective conductive connection structure of the second column of conductive connection structures may be not in a same row. In other words, in the second direction, the first and second column of conductive connection structures are arranged in a stagger manner relative to each other. Alternatively, some conductive connection structures of the first column of conductive connection structures and respective conductive connection structures of the second column of conductive connection structures are respectively arranged in a same row. The present disclosure does not specifically limit the conductive connection structures <NUM>, as long as the plurality of conductive connection structures <NUM> form an array.

In some embodiments, a width of the at least one conductive connection structure <NUM> in the second direction Y ranges from <NUM> to <NUM>, such as <NUM>, <NUM>, <NUM> or the like. It should be understood that when the width of the at least one conductive connection structure <NUM> is less than <NUM>, the transverse transferring capacity of each conductive connection structure <NUM> is weak, and the conductive connection structure cannot provide good improving effect. When the width of the at least one conductive connection structure <NUM> is greater than <NUM>, the conductive connection structure <NUM> may have a high-level parasitic absorption of light, which is detrimental to the improvement of photoelectric conversion efficiency of the solar cell. In some other embodiments, the width of the at least one conductive connection structure <NUM> may have other values, which may be determined according to actual situation.

In some embodiments, a top surface of the at least one conductive connection structure <NUM> is lower than or flush with a top surface of a protrusion <NUM>. In other words, in a direction perpendicular to the surface of the substrate <NUM>, a thickness of the at least one conductive connection structure <NUM> is less than or equal to a thickness of a protrusion <NUM>. When the top surface of the conductive connection structure <NUM> is lower than the top surface of the protrusion <NUM>, light-absorption capacity of the conductive connection structure <NUM> can be reduced, which is conducive to improving photoelectric conversion efficiency of the solar cell. When the top surface of the conductive connection structure <NUM> is flush with the top surface of the protrusion <NUM>, the production process of the solar cell can be simplified, and the protrusions <NUM> and the at least one conductive connection structure <NUM> can be formed in a same process operation by laser ablation. In some other embodiments, the top surface of the conductive connection structure <NUM> may be higher than the top surface of the protrusion <NUM>, which may be determined according to actual situation.

In some embodiments, in the direction perpendicular to the surface of the substrate <NUM>, a height of the at least one conductive connection structure <NUM> may be <NUM> to <NUM> times of a height of a protrusion <NUM>. When the height of the conductive connection structure <NUM> is less than <NUM> times of the height of the protrusion <NUM>, the conductive connection structure <NUM> is relatively thin, which results in a relatively weak transverse transferring capacity and a not prominent improvement. When the height of the conductive connection structure <NUM> is greater than <NUM> times of the height of the protrusion <NUM>, the conductive connection structure <NUM> is relatively thick, which results in a relatively strong capacity of parasitic absorption of light of the conductive connection structure <NUM> and therefore a reduction in the photoelectric conversion efficiency of the solar cell.

In some embodiments, the solar cell further includes at least one busbar <NUM> extending along the first direction X and electrically connected with the plurality of finger electrodes <NUM> arranged along the first direction X. Through the at least one busbar <NUM>, the currents collected by the plurality of finger electrodes <NUM> can be converged and outputted from the solar cell.

In some embodiments, the plurality of conductive connection structures <NUM> are spaced from the at least one busbar <NUM>. In this way, the at least one busbar <NUM> can be limited by the plurality of conductive connection structures <NUM>, which is conducive to the subsequent printing of the at least one busbar <NUM>. Moreover, the position of the at least one busbar <NUM> can be determined without additional positioning operation, which is conducive to the production operations.

In some embodiments, a column of conductive connection structures <NUM> arranged at intervals along the first direction X may be formed between adjacent busbars <NUM>. In some other embodiments, more than one column of conductive connection structures <NUM> arranged at intervals along the first direction X may be formed between adjacent busbars <NUM>. The present disclosure does not limit the number of the conductive connection structures <NUM> between adjacent busbars <NUM>, which may be determined according to actual situation.

In some embodiments, projections of the plurality of conductive connection structures <NUM> on the substrate <NUM> are at least partially overlapped with a projection of the at least one busbar <NUM> on the substrate <NUM>. The busbar <NUM> is generally of non-sintered type and used to collect the photo-generated carriers collected by the plurality of finger electrodes <NUM>. That is to say, the busbar <NUM> will not corrode the structure under the busbar <NUM>, so that the conductive connection structures <NUM> formed under the busbar <NUM> will not be affected by the busbar. Therefore, the transverse transferring capacity of the conductive connection structures <NUM> will not be affected. Moreover, the busbar <NUM> that at least shields a part of each conductive connection structures <NUM> can reduce capacity of parasitic absorption of light of the conductive connection structures <NUM>, thereby improving the photoelectric conversion efficiency of the solar cell.

In some embodiments, the solar cell includes a plurality of busbars, and there are at least two columns of conductive connection structures <NUM> arranged along the first direction X on a side of a peripheral busbar <NUM> towards an edge of the substrate. In some other embodiments, no conductive connection structure or one column of conductive connection structures arranged along the first direction is formed on the side of the peripheral busbar towards the edge of the substrate. By forming at least two columns of conductive connection structures <NUM>, the number of the conductive connection structures <NUM> can be increased, thereby improving the transverse transferring capacity of the solar cell.

In some embodiments, the solar cell has a front surface and a rear surface. The front surface is a light receiving surface that absorbs incident light, and the rear surface is a surface opposite to the front surface. The tunneling dielectric layer <NUM>, the doped conductive layer <NUM>, the at least one conductive connection structure <NUM>, the passivation layer <NUM> and the plurality of finger electrodes <NUM> may be respectively formed over the front surface and the rear surface of the solar cell.

In some embodiments, a doped conductive layer <NUM> formed over the rear surface of the solar cell and the substrate <NUM> are of a same doping type, and a doped conductive layer <NUM> formed over the front surface of the solar cell and the substrate <NUM> are of different doping types. Taking the substrate <NUM> being an N-type substrate as an example, doping type of the doped conductive layer <NUM> formed over the rear surface of the solar cell is N type, and doping type of the doped conductive layer <NUM> formed over the front surface of the solar cell is P type.

In the embodiments of the present disclosure, the tunneling dielectric layer <NUM> and the doped conductive layer <NUM> are formed over the substrate <NUM>, and the doped conductive layer <NUM> has a plurality of protrusions <NUM>, thereby forming height differences on the doped conductive layer <NUM>. In this way, contacts between the plurality of finger electrodes <NUM> and the doped conductive layer <NUM> can be ensured, and the parasitic absorption of light of the doped conductive layer <NUM> can be reduced. At least one conductive connection structure <NUM> is formed between adjacent protrusions <NUM> of the doped conductive layer <NUM>, and the adjacent protrusions <NUM> are connected by the conductive connection structure <NUM>. In this way, the transverse transferring capacity of the doped conductive layer <NUM> can be improved, thereby increasing the transfer rate of the solar cell.

Referring to <FIG>, embodiments of the present disclosure provide a photovoltaic module configured to convert the received light energy into electrical energy and transfer it to external loads. The photovoltaic module includes at least one cell string <NUM>, at least one encapsulation layer <NUM> and at least one cover plate <NUM>. The at least one cell string <NUM> includes a plurality of solar cells as described above (such as, <FIG>), and the plurality of solar cells are electrically connected in sequence. The at least one encapsulation layer is configured to cover a surface of the at least one cell string. The at least one cover plate is configured to cover a surface of the at least one encapsulation layer <NUM> facing away from the at least one cell string.

The at least one encapsulation layer <NUM> may be an organic encapsulation adhesive film such as an ethylene vinyl acetate copolymer (EVA) adhesive film, or a polyethylene octene copolymer (POE) adhesive film. The encapsulation layer <NUM> covers a surface of the cell string to seal and protect the cell string. In some embodiments, the encapsulation layers <NUM> includes an upper encapsulation adhesive film and a lower encapsulation adhesive film that respectively cover an upper surface and a lower surface of the cell string. The at least one cover plate <NUM> may be a cover plate for protecting the cell string, such as a glass cover plate, a plastic cover plate or the like. The at least one cover plate <NUM> covers a surface of the encapsulation layer <NUM> facing away from the cell string. In some embodiments, the cover plate <NUM> has a light trapping structure to increase the utilization rate of the incident light. In this way, the photovoltaic module can have high current-collection capacity, low carrier recombination rate, and therefore high photoelectric conversion efficiency. In some embodiments, the cover plates <NUM> include an upper cover plate and a lower cover plate located on either sides of the cell string.

Claim 1:
A solar cell, comprising:
a substrate (<NUM>);
a tunneling dielectric layer (<NUM>) formed on the substrate (<NUM>);
a doped silicon layer (<NUM>) formed on the tunneling dielectric layer (<NUM>), wherein the doped silicon layer (<NUM>) has a plurality of protrusions (<NUM>) arranged along a first direction (X), and each protrusion of the plurality of protrusions (<NUM>) extends along a second direction (Y) perpendicular to the first direction (X);
a plurality of silicon connection structures (<NUM>) formed at intervals along the first direction (X) and along the second direction (Y), wherein each silicon connection structure of the plurality of silicon connection structures (<NUM>) is formed between two respective adjacent protrusions (<NUM>) and is connected with sidewalls of the two respective adjacent protrusions (<NUM>);
a passivation layer (<NUM>) over the doped silicon layer (<NUM>) and the plurality of silicon connection structures (<NUM>); and
a plurality of finger electrodes (<NUM>), wherein each finger electrode of the plurality of finger electrodes (<NUM>) extends along the second direction (Y) to penetrate the passivation layer (<NUM>) and connect to a respective protrusion, and there is at least one finger electrode (<NUM>) between adjacent silicon connection structures (<NUM>) in the first direction (X).