Patent Description:
Factors affecting the performance of photovoltaic cells (e.g., photoelectric conversion efficiency) include optical loss and electrical loss. The optical loss includes reflection loss of a front surface of the cell, shadow loss of contacted grid lines, non-absorption loss of long-wavelength light, and the like. The electrical loss includes loss of photogenerated carrier recombination on a surface of a semiconductor and inside the semiconductor, loss of contact resistance between the semiconductor and metal grid lines, loss of contact resistance between the metal and the semiconductor, and the like.

In order to reduce the electrical and optical losses of the photovoltaic cells, the rear surface of the photovoltaic cell generally needs to be polished. The rear surface polishing process mainly uses a wet chemical method to polish a rear boron-doped pyramid pile structure, which increases internal reflection of light, reduces a recombination rate of carriers on the surface, and improves the photoelectric conversion efficiency of the cell. In the rear surface polishing process, a morphology of a polished rear surface of a silicon crystal cell is conducive to rear reflection of long-wavelength light and uniformity of subsequent film layers formed on the rear surface, which plays an important role in improving the efficiency of the photovoltaic cells. The rear surface polishing process improves the performance of the photovoltaic cells, but there are still many factors affecting the performance of this type of photovoltaic cells. It is of great significance to develop high-efficiency passivated contact photovoltaic cells.

Document <CIT> discloses an interdigitated back contact photovoltaic cell, with dopants of a first and second conductivity type that are provided in patterned layers of the active region of the semiconductor substrate near the back side.

Some embodiments of the present disclosure provide a photovoltaic cell and a photovoltaic module, which are at least conducive to improving photoelectric conversion efficiency of the photovoltaic cell.

Some embodiments of the present disclosure provide a photovoltaic cell including: a substrate; a doped layer disposed in a portion of the substrate adjacent to a first surface of the substrate, where a doping element type of the doped layer is the same as a doping element type of the substrate, and a doping concentration of the doped layer is greater than a doping concentration of the substrate, where the doped layer includes a plurality of first doped regions arranged at intervals along a first direction, a plurality of second doped regions disposed between respective two adjacent first doped regions and a plurality of third doped regions disposed between the respective two adjacent first doped regions, and where a doping concentration of each of the plurality of first doped regions is less than a doping concentration of any of the plurality of second doped regions and less than a doping concentration of any of the plurality of third doped regions; at least one tunneling dielectric layer disposed on the plurality of first doped regions and the plurality of second doped regions; a plurality of doped conductive layers arranged at intervals along the first direction, where each of the plurality of doped conductive layers is aligned with a respective first doped region and is disposed on a respective tunneling dielectric layer; a plurality of first electrodes arranged at intervals along the first direction, where the plurality of first electrodes extend in a second direction, each of the plurality of first electrodes is disposed on a side of a respective doped conductive layer away from the substrate and electrically connected to the respective doped conductive layer; and a plurality of conductive transport layers each aligned with a respective second doped region, where the plurality of conductive transport layers are disposed on the at least one tunneling dielectric layer, and each of the plurality of conductive transport layers is disposed between respective two adjacent doped conductive layers and is in contact with side walls of the respective two adjacent doped conductive layer.

In some embodiments, a doping concentration of each of the plurality of second doping regions is less than or equal to a doping concentration of each of the plurality of third doping regions.

In some embodiments, a doping depth of each of the plurality of first doped regions is less than a doping depth of each of the plurality of second doped regions in a direction perpendicular to the first surface.

In some embodiments, a doping depth of each of the plurality of second doping regions is less than or equal to a doping depth of each of the plurality of third doping regions in a direction perpendicular to the first surface.

In some embodiments, a doping depth of each of the plurality of first doped regions is in a range of <NUM> to <NUM>, a doping depth of each of the plurality of second doping regions is in a range of <NUM> to <NUM>, and a doping depth of each of the plurality of third doping regions is in a range of <NUM> to <NUM>.

In some embodiments, the doping concentration of each of the plurality of first doped regions is in a range of 5E19cm-<NUM> to 1E21cm-<NUM>, the doping concentration of each of the plurality of second doped regions is in a range of 1E20cm-<NUM> to 3E21cm-<NUM>, and the doping concentration of each of the plurality of third doped regions is in a range of 5E17cm-<NUM> to 1E20cm-<NUM>.

In some embodiments, a total doping amount of the plurality of first doped regions is less than a total doping amount of the plurality of second doped regions and less than a total doping amount of the plurality of third doped regions.

In some embodiments, a doping element type of each of the plurality of doped conductive layers is the same as the doping element type of the doped layer, and the doping concentration of the doped layer is less than a doping concentration of each of the plurality of doped conductive layers.

In some embodiments, a doping element type of each of the plurality of conductive transport layers is the same as the doping element type of the doped layer.

In some embodiments, a doping concentration of each of the plurality of conductive transport layers is greater than the doping concentration of the doped layer.

In some embodiments, each of the plurality of conductive transport layers includes body portions arranged at intervals along the first direction and a connection portion between the body portions, where the body portions are in contact with side walls of the respective two adjacent doped conductive layers, and a doping concentration of each of the body portions is less than or equal to a doping concentration of the connection portion.

In some embodiments, each of the plurality of second doping regions includes first sub-doping portions and a second sub-doping portion, where each of the first sub-doping portions is aligned with a respective body portion, the second sub-doping portion is aligned with the connection portion, and a doping concentration of each of the first sub-doping portions is less than or equal to a doping concentration of the second sub-doping portion.

In some embodiments, a doping depth of each of the first sub-doping portions is less than or equal to a doping depth of the second sub-doping portion in a direction perpendicular to the first surface.

In some embodiments, a ratio of a total area of connection portions in the plurality of conductive transport layers to a total area of the plurality of conductive transport layers is in a range of <NUM>:<NUM> to <NUM>:<NUM>.

In some embodiments, a material of the doped layer includes at least one of single crystal silicon, microcrystal silicon, amorphous silicon and polysilicon.

In some embodiments, the material of the doped layer is the same as at least one of a material of the substrate, a material of each of the plurality of doped conductive layers, and a material of each of the plurality of conductive transport layers.

In some embodiments, the photovoltaic cell further includes a passivation layer disposed on the plurality of doped conductive layers, the plurality of conductive transport layers, and the plurality of third doped regions.

In some embodiments, the photovoltaic cell further includes a plurality of second electrodes arranged at intervals along the second direction, where the plurality of second electrodes extend along the first direction and electrically connected to the plurality of first electrodes arranged at intervals along the first direction.

In some embodiments, at least one conductive transport layer is disposed between two adjacent the second electrodes, and the photovoltaic cell further includes a plurality of conductive connection layers each disposed between a respective conductive transport layer and a respective second electrode, opposite side walls of each of the plurality of conductive connection layers are respectively in contact with a side wall of the respective conductive transport layer and a side wall of the respective second electrode.

In some embodiments, the doped layer further includes a plurality of fourth doped regions each aligned with a respective conductive connection layer, and a doping concentration of each of the plurality of fourth doped regions is greater than or equal to a doping concentration of each of the plurality of first doped regions and less than or equal to a doping concentration of each of the plurality of third doped regions.

Some embodiments of the present disclosure provide a photovoltaic module including: at least one cell string, each of the at least one cell string formed by a plurality of photovoltaic cells according to the above embodiments which are electrically connected; at least one encapsulation layer, each of the at least one encapsulation layer configured to cover a surface of a respective cell string; and at least one cover plate, each of the at least one cover plate configured to cover a surface of a respective encapsulation layer facing away from the respective cell string.

One or more embodiments are described as examples with reference to the corresponding figures in the accompanying drawings, and the examples do not constitute a limitation to the embodiments. The figures in the accompanying drawings do not constitute a proportion limitation unless otherwise stated. In order to more clearly describe embodiments of the present disclosure or technical solutions in conventional technologies, the accompanying drawings required to be used in the embodiments are briefly described below. Apparently, the accompanying drawings in the following description are merely related to some embodiments of the present disclosure, and those of ordinary skill in the art may obtain other drawings from these drawings without creative efforts.

It is seen from BACKGROUND that, generally, conventional photovoltaic cells have low photoelectric conversion efficiency.

It is found that reasons for the low photoelectric conversion efficiency of the conventional photovoltaic cells are at least the following. In order to improve the photoelectric conversion efficiency of the photovoltaic cell, a doping concentration of a substrate is usually increased to improve a transporting rate of most of carriers in the substrate. However, a doping conductive layer with a larger doping concentration is generally provided in a region of the substrate where the electrode is directly facing. When both the doping concentration of the substrate and the doping concentration of the doping conductive layer are large, a band gap of a portion of the substrate in the region where the electrode is directly facing may decrease, resulting in reduction of an open-circuit voltage of the photovoltaic cell, which may cause decay of the electric field. Moreover, a high doping effect may occur in the large doping concentration, and a dark current may occur or a composite current due to a tunneling effect of most carriers may occur, thereby reducing the short-circuit current.

Embodiments of the present disclosure provides a photovoltaic cell, a doped layer is disposed on a first surface of a substrate, and the doped layer includes a plurality of first doped regions, a plurality of second doped regions and a plurality of third doped regions. A respective doped conductive layer and a respective first electrode are disposed in each first doped region, a respective conductive transport layer is disposed in each second doped region, and no first electrode and doped conductive layer is disposed in each third doped region. In order to improve the contact between the doped conductive layers and the first electrodes, the doped conductive layers are usually configured to be highly doped. In the embodiments of the present disclosure, the doping concentration of each first doped region is less than the doping concentration of each second doped region and less than the doping concentration of each third doped region. On the one hand, the decrease of the band gap of the substrate due to the excessive concentration of the doping elements below the first electrode is avoided, so that the reduction of the open-circuit voltage of the photovoltaic cell and the decay of the electric field are avoided. On the other hand, a high doping effect (e.g., a tunneling effect produces a composite current) caused by an excessive doping concentration of the doped conductive layers and the excessive doping concentration of the doped layer is avoided. However, by providing the plurality of second doping regions and the plurality of third doping regions with large doping concentrations, the carrier transporting efficiency in the region unaligned with the first electrodes is improved, so that the open-circuit voltage of the photovoltaic cell is increased, which is conducive to improving the photoelectric conversion efficiency of the photovoltaic cell.

In addition, the doping concentration of the doped layer is greater than the doping concentration of the substrate, and a high-low junction is formed between the doped layer and the substrate, so that a built-in electric field is formed between the doped layer and the substrate, positive space charges are formed on the surface of the doped layer with the greater doping concentration, and negative space charges are formed on the surface of the substrate with the less doping concentration, thereby most carriers in the substrate are easily drift to the doped layer with the greater doping concentration, which is conducive to increasing an output current of the photovoltaic cell. Meanwhile, due to the existence of the built-in electric field, there is a potential barrier between the substrate and the doped layer, thus blocking the drift of majority carriers in the doped layer with the greater doping concentration to the substrate with the less doping concentration.

Various embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Those of ordinary skill in the art should appreciate that many technical details have been proposed in various embodiments of the present disclosure for the better understanding of the present disclosure. However, the technical solutions claimed in the present disclosure are able to be realized even without these technical details and various changes and modifications based on the following embodiments.

<FIG> is a schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is a schematic structural diagram of a doped layer in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is a partial and cross-sectional schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is another partial and cross-sectional schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is yet another partial and cross-sectional schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is a schematic diagram of carrier transporting in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is another schematic diagram of carrier transporting in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is yet another schematic diagram of carrier transporting in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is an Electrochemical Capacitance Voltage (ECV) doping concentration graph of a doped layer in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> and <FIG> show cross-sectional views along an A<NUM>-A<NUM> direction of a structure in <FIG>, <FIG> and <FIG> show cross-sectional views along an B<NUM>-B<NUM> direction of the structure in <FIG>, and <FIG> and <FIG> show cross-sectional views along an C<NUM>-C<NUM> direction of the structure in <FIG>.

Referring to <FIG>, a photovoltaic cell includes a substrate <NUM>, a doped layer <NUM>, at least one tunneling dielectric layer <NUM>, a plurality of doped conductive layers <NUM>, a plurality of first electrodes <NUM>, and a plurality of conductive transport layers <NUM>. The doped layer <NUM> is disposed in a portion of the substrate <NUM> adjacent to a first surface of the substrate <NUM>, a doping element type of the doped layer <NUM> is the same as a doping element type of the substrate <NUM>, and a doping concentration of the doped layer <NUM> is greater than a doping concentration of the substrate <NUM>. The doped layer <NUM> includes a plurality of first doping regions <NUM> arranged at intervals along a first direction Y, a plurality of second doping regions <NUM> between respective two adjacent first doping regions <NUM>, and a plurality of third doping regions <NUM> between the respective two adjacent first doping regions <NUM>. A doping concentration of each of the plurality of first doping regions <NUM> is less than a doping concentration of each of the plurality of second doping regions <NUM> and less than a doping concentration of each of the plurality of third doping regions <NUM>. The at least one tunneling dielectric layer <NUM> is disposed on the plurality of first doped regions <NUM> and the plurality of second doped regions <NUM>. The plurality of doped conductive layers <NUM> are arranged at intervals along the first direction Y, and each of the plurality of doped conductive layers <NUM> is aligned with a respective first doped region <NUM> and disposed on a respective tunneling dielectric layer <NUM>. The plurality of first electrodes <NUM> are arranged at intervals along the first direction Y, the plurality of first electrodes <NUM> extend along a second direction X, and each of the plurality of first electrodes <NUM> is disposed on a side of a respective doped conductive layer <NUM> away from the substrate <NUM> and electrically connected to the respective doped conductive layer <NUM>. Each of the plurality of conductive transport layers <NUM> is aligned with a respective second doped region <NUM> and disposed on a respective tunneling dielectric layer <NUM>, and each of the plurality of conductive transport layers <NUM> is disposed between respective two adjacent doped conductive layers <NUM> and in contact with side walls of the respective two adjacent doped conductive layers <NUM>.

The substrate <NUM> is configured to receive incident light and generate photogenerated carriers. In some embodiments, a material of the substrate <NUM> may include at least one of monocrystalline silicon, polysilicon, amorphous silicon, or microcrystalline silicon. In some embodiments, a material of the substrate <NUM> may also include silicon carbide, an organic material, or multicomponent compounds. The multicomponent compounds may include, but are not limited to, materials such as perovskite, gallium arsenide, cadmium telluride, copper indium selenium, and the like.

In some embodiments, the substrate <NUM> has doping elements, and a type of the doping elements includes N-type or P-type. The N-type elements may be group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), arsenic (As), or the like. The P-type elements may be group III elements such as boron (B), aluminum (Al), gallium (Ga), indium (In), or the like. For example, when the substrate <NUM> is a P-type substrate, the type of the doping elements in the substrate <NUM> is P-type. Alternatively, when the substrate <NUM> is an N-type substrate, the type of the doping elements in the substrate <NUM> is N-type. Specifically, in some embodiments, the substrate <NUM> may be the N-type substrate, and the substrate <NUM> may be doped with N-type doping ions, e.g., any of phosphorus ions, bismuth ions, antimony ions, or arsenic ions.

In some embodiments, the photovoltaic cell is a tunnel oxide passivated contact (TOPCON) cell, the substrate <NUM> further includes a second surface disposed opposite the first surface, and both the first surface and the second surface of the substrate <NUM> may be configured to receive incident or reflected light. In some embodiments, the first surface may be a rear surface of the substrate <NUM>, and the second surface may be a front surface of the substrate <NUM>. In some embodiments, the first surface may be the front surface of the substrate <NUM>, and the second surface may be the rear surface of the substrate <NUM>.

In some embodiments, the first surface of the substrate <NUM> may be provided as a non-pyramidal texture surface, such as a laminated step morphology, such that the tunneling dielectric layers <NUM> disposed on the first surface of the substrate <NUM> have a high degree of density and uniformity and thus having a good passivation effect on the first surface of the substrate <NUM>. The second surface of the substrate <NUM> may be provided as a pyramid texture surface such that the second surface of the substrate <NUM> has a lower reflectivity to the incident light and thus having a large absorption and utilization rate of the light.

In some embodiments, the material of the doped layer <NUM> includes at least one of monocrystalline silicon, microcrystalline silicon, amorphous silicon, or polysilicon.

The material of the doped layer <NUM> is the same as at least one of the material of the substrate <NUM>, the material of the doped conductive layers <NUM>, or the material of the conductive transport layers <NUM>. In some embodiments, when the material of the doped layer <NUM> is the same as the material of the substrate <NUM>, the doped layer <NUM> and the substrate <NUM> may be considered the same original substrate, the doped layer <NUM> is disposed in a portion of the original substrate adjacent to the first surface of the original substrate, and upper surfaces of the first doped regions <NUM>, the second doped regions <NUM>, and the third doped regions <NUM> in the doped layer <NUM> are flush with each other. The material of the doped layer <NUM> is the same as that of the substrate <NUM>, thereby avoiding recombination of partial carriers and reduced efficiency of the cell, which are caused by no interface state defect between the doped layer <NUM> and the substrate <NUM> due to the consumption of photogenerated carriers due to the electrical conductivity of different materials. In some embodiments, lower surfaces of the first doped regions <NUM>, the second doped regions <NUM>, and the third doped regions <NUM> are flush with each other.

In some embodiments, the doped layer is also a diffusion layer, which may be formed by a separate diffusion process (i.e., direct doping on the surface of the doped layer), or may be a portion of the substrate having a greater doping concentration than the substrate, which is formed by doping elements of diffusion processes in which the doped conductive layers and the conductive transport layers are formed penetrating into the substrate (such that this portion of the substrate (i.e., the doped layer) having the greater doping concentration than the substrate), or may be formed by a combination of the above two manners.

In addition, the open-circuit voltage is related to a band gap Eg of the material. The closer a Fermi level of the material to the top of a conduction band and the top of a full band, the higher a built-in barrier voltage of a PN junction, the larger the open-circuit voltage, and the easier the carriers to transition. When the material of the doped layer <NUM> is different from the material of the substrate <NUM>, the carriers need to transition an interface barrier region between the substrate <NUM> and the doped layer <NUM> and interface barrier regions between the doped layer <NUM> and the tunneling dielectric layers <NUM>, so that the consumption of the carriers is large. Moreover, band gaps of various materials are different, i.e., the open-circuit voltages thereof are also different, and the mobility of carriers in different materials is also different, thereby affecting the efficiency of the cell.

It should be understood that since the doping concentration of each third doped region <NUM> is greater than that of each first doped region <NUM> and that of each second doped region <NUM>, the time for laser processing in each third doped region <NUM> is larger than the time for laser processing in each second doped region <NUM> and in each first doped region <NUM> when laser doping is used, so that the upper surface of the third doped region <NUM> away from the substrate <NUM> is lower than that of the second doped region <NUM> and that of the first doped region <NUM>.

In some embodiments, referring to <FIG>, the doping concentration of the doped layer <NUM> is greater than the doping concentration of the substrate <NUM>, and a high-low junction is formed between the doped layer <NUM> and the substrate <NUM>, so that a built-in electric field is formed between the doped layer <NUM> and the substrate <NUM>, positive space charges are formed on the surface of the doped layer <NUM> with the greater doping concentration, and negative space charges are formed on the surface of the substrate <NUM> with the less doping concentration, thereby most carriers in the substrate <NUM> are easily drift to the doped layer <NUM> with the greater doping concentration, which is conducive to increasing an output current of the photovoltaic cell. Meanwhile, due to the existence of the built-in electric field, there is a potential barrier between the substrate <NUM> and the doped layer <NUM>, thus blocking the drift of majority carriers in the doped layer <NUM> with the greater doping concentration to the substrate <NUM> with the less doping concentration.

In some embodiments, in the first direction Y, the second doping regions <NUM> are located between adjacent two first doping regions <NUM> and the third doping regions <NUM> are located between adjacent two first doping regions <NUM>; in the second direction X, the second doped regions <NUM> are interleaved with the third doped regions <NUM>.

A total doping amount of the first doped regions is less than a total doping amount of the second doped regions and less than a total doping amount of the third doped regions. The total doping amount of the first doped regions <NUM> may be understood as a total amount of doping elements in the first doped regions <NUM>, and the total doping amount is related to the doping concentration and the doping depth. The total doping amount of the second doped regions <NUM> may be understood as a total amount of doping elements in the second doped regions <NUM>, and the total doping amount of the third doped regions <NUM> may be understood as a total amount of doping elements in the third doped regions <NUM>. The total doping amount of the first doped regions <NUM> being less than the total doping amount of the second doped regions <NUM> and less than the total doping amount of the third doped regions <NUM> means that the doping concentration of each first doped region <NUM> is less than the doping concentration of each second doped region <NUM> and less than the doping concentration of each third doped region <NUM>, or a doping depth of each first doped region <NUM> is less than a doping depth of each second doped region <NUM> and less than a doping depth of each third doped region <NUM>, alternatively, means that the doping concentration of each first doped region <NUM> is less than the doping concentration of each second doped region <NUM> and less than the doping concentration of each third doped region <NUM>, and the doping depth of each first doped region <NUM> is less than the doping depth of each second doped region <NUM> and less than the doping depth of each third doped region <NUM>. In conventional technologies, in order to improve the contact between the doped conductive layers <NUM> and the first electrodes <NUM>, the doped conductive layers are usually configured to be highly doped. In the embodiments of the present disclosure, the total doping amount of the first doped regions <NUM> is less than the total doping amount of the second doped regions <NUM> and less than the total doping amount of each third doped regions <NUM>. On the one hand, the decrease of the band gap of the substrate <NUM> due to the excessive concentration of the doping elements below the first electrodes <NUM> is avoided, so that the reduction of the open-circuit voltage of the photovoltaic cell and the decay of the electric field are avoided. On the other hand, a high doping effect (e.g., a tunneling effect produces a composite current) caused by an excessive doping concentration of the doped conductive layers <NUM> and the excessive doping concentration of the doped layer <NUM> is avoided. However, by providing the plurality of second doping regions <NUM> with the large doping concentration and the plurality of third doping regions <NUM> with the large doping concentration, the carrier transporting efficiency in the region unaligned with the first electrodes is improved, so that the open-circuit voltage of the photovoltaic cell is increased, which is conducive to improving the photoelectric conversion efficiency of the photovoltaic cell.

In some embodiments, referring to <FIG>, the doping depth of each first doped region <NUM> is a range of <NUM> to <NUM>, preferably, the doping depth of the first doped region <NUM> is in a range of <NUM> to <NUM>, in particular <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. The doping concentration of each first doped region <NUM> is in a range of 5E19 cm-<NUM> to 1E21 cm-<NUM>, and optionally, the doping concentration of the first doped region <NUM> is in a range of 8E19 cm-<NUM> to 9E20 cm-<NUM>, in particular 9E19 cm-<NUM>, <NUM>. 2E20 cm-<NUM>, <NUM>. 5E20 cm-<NUM>, <NUM>. 8E20 cm-<NUM>, 9E20 cm-<NUM>, etc..

In some embodiments, the doping depth of each second doped region <NUM> is in a range of <NUM> to <NUM>, preferably, the doping depth of the second doped region <NUM> is in a range of <NUM> to <NUM>, in particular <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. The doping concentration of each second doped region <NUM> is in a range of 1E20 cm-<NUM> to 3E21 cm-<NUM>, and optionally, the doping concentration of the second doped region <NUM> is in a range of 2E20 cm-<NUM> to <NUM>. 5E21 cm-<NUM>, in particular 2E20 cm-<NUM>, 5E20 cm-<NUM>, 8E20 cm-<NUM>, <NUM>. 6E21 cm-<NUM>, <NUM>. 5E21 cm-<NUM>, etc..

In some embodiments, the doping depth of each third doped region <NUM> is in a range of <NUM> to <NUM>, preferably, the doping depth of the third doped region <NUM> is in a range of <NUM> to <NUM>, in particular <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, etc. The doping concentration of each third doped region <NUM> is in a range of 5E17 cm-<NUM> to 1E20 cm-<NUM>, and optionally, the doping concentration of the third doped region <NUM> is in a range of 6E17 cm-<NUM> to 1E20 cm-<NUM>, in particular 6E17 cm-<NUM>, 4E18 cm-<NUM>, 1E19 cm-<NUM>, <NUM>. 3E19 cm-<NUM>, 1E20 cm-<NUM>, etc..

In some embodiments, the total doping amount of the second doped regions <NUM> is less than or equal to the total doping amount of the third doped regions <NUM>, including the doping concentration of each second doped region <NUM> is less than or equal to the doping concentration of each third doped region <NUM> or the doping depth of each second doped region <NUM> is less than or equal to the doping depth of each third doped region <NUM>, alternatively, including the doping concentration of each second doped region <NUM> is less than or equal to the doping concentration of each third doped region <NUM> and the doping depth of each second doped region <NUM> is less than or equal to the doping depth of each third doped region <NUM>. The conductive transport layers <NUM> are disposed between adjacent two doped conductive layers <NUM>. The conductive transport layers <NUM> are configured to enhance the transport capability of the cell and is in direct contact with the side walls of the doped conductive layers <NUM>. The low doping of the second doped regions <NUM> that are aligned with the doped conductive layers <NUM> is able to avoid the high doping effect (e.g., the tunneling effect produces the composite current).

In some embodiments, the tunneling dielectric layers <NUM> and the doped conductive layers <NUM> may be configured to constitute a passivation contact structure on the surface of the substrate <NUM>. By forming the tunneling dielectric layers <NUM> and the doped conductive layers <NUM>, the recombination of carriers on the surface of the substrate <NUM> may be reduced, thereby increasing the open-circuit voltage of the photovoltaic cell and improving the photoelectric conversion efficiency of the photovoltaic cell. Specifically, the tunneling dielectric layers <NUM> may reduce the defect state concentration of the first surface of the substrate <NUM> so as to reduce the recombination center of the first surface of the substrate <NUM>, thereby reducing the recombination rate of carriers.

The doped conductive layers <NUM> are configured to form a field passivation layer to make the minority carriers escape from the interface, so as to reduce the concentration of the minority carriers, so that the recombination rate of carriers at the interface of the substrate <NUM> is low, and the open-circuit voltage, the short-circuit current and the filling factor of the photovoltaic cell are large, thereby improving the photoelectric conversion performance of the photovoltaic cell. In some embodiments, the doped conductive layers <NUM> have doping elements of the same conductivity type as the substrate <NUM>.

The plurality of doped conductive layers <NUM> extend along the second direction X, and the plurality of doped conductive layers <NUM> are arranged at intervals in the first direction Y perpendicular to the second direction X. In some embodiments, the plurality of first electrodes <NUM> are in one-to-one correspondence with the plurality of doped conductive layers <NUM>, i.e., each of the plurality of first electrodes <NUM> is electrically connected to a respective one of the plurality of doped conductive layers <NUM>. That is, the doped conductive layers <NUM> are provided only in the region corresponding to the first electrodes <NUM>, so that the parasitic absorption effect of the region in which the first electrode <NUM> is not provided is reduced, and the utilization of the substrate <NUM> to light is improved. In some embodiments, the material of the first electrodes <NUM> may include at least one of silver, aluminum, copper, tin, gold, lead, or nickel.

The tunneling dielectric layers <NUM> and the doped conductive layers <NUM> are stacked. Specifically, in some embodiments, the tunneling dielectric layers <NUM> may cover the entire first surface of the substrate <NUM>, and a plurality of doped conductive layers <NUM> are disposed at intervals on a top surface of the whole tunneling dielectric layer <NUM>. In some embodiments, the tunneling dielectric layers <NUM> are disposed with respect to the doped conductive layers <NUM>, i.e., a respective tunneling dielectric layers <NUM> is disposed between a corresponding doped conductive layer <NUM> and the substrate <NUM>. Moreover, a respective tunneling dielectric layer <NUM> is also disposed between a corresponding conductive transport layer <NUM> and the substrate <NUM>, so that this portion of the tunneling dielectric layer <NUM> is capable of reducing the carrier recombination of the first surface of the substrate <NUM>, thereby increasing the concentration of carriers transported into the conductive transport layer <NUM>.

In some embodiments, the material of the tunneling dielectric layer <NUM> may include, but is not limited to, a dielectric material having the tunneling effect, such as aluminum oxide, silicon oxide, silicon nitride, silicon oxynitride, intrinsic amorphous silicon, intrinsic polysilicon, and the like. Specifically, the tunneling dielectric layer <NUM> may be formed of a silicon oxide layer including silicon oxide (SiOx), because the silicon oxide has good passivation characteristics and carriers are able to easily tunnel the silicon oxide layer.

In some embodiments, the material of the conductive transport layer <NUM> is the same as that of the doped conductive layer <NUM>. By providing the conductive transport layer <NUM> with the same material as the doped conductive layer <NUM>, on the one hand, types of the materials throughout the production process are reduced for ease of management; on the other hand, the contact between the conductive transport layer <NUM> and the doped conductive layer <NUM> is good, so that the carriers have a good transport effect at the contact interfaces between the doped conductive layer <NUM> and the conductive transport layer <NUM>, thereby reducing the transport loss. In addition, the transport rate of carriers in the conductive transport layer <NUM> may be similar to or the same as the transport rate of carriers in the doped conductive layer <NUM>, thereby improving the transport efficiency of carriers from the conductive transport layer <NUM> to the doped conductive layer <NUM>. It should be noted that the conductive transport layer <NUM> have the same material as the doped conductive layers herein means that the type of doping ions in the conductive transport layer <NUM> are the same as those in the doped conductive layer <NUM>.

In some embodiments, the material of the doped conductive layer <NUM> includes at least one of doped amorphous silicon, doped polysilicon, or doped microcrystalline silicon. Accordingly, the material of the conductive transport layer <NUM> may also include at least one of doped amorphous silicon, doped polysilicon, or doped microcrystalline silicon.

It should be appreciated that in some embodiments, the material of the conductive transport layer <NUM> may also be different from the material of the doped conductive layer <NUM>. For example, the material of the conductive transport layer <NUM> may include one of doped amorphous silicon, doped polysilicon, or doped microcrystalline silicon, and the material of the doped conductive layer <NUM> may include the other of doped amorphous silicon, doped polysilicon, or doped microcrystalline silicon.

In some embodiments, when the material of the conductive transport layer <NUM> is different from the material of the doped conductive layer <NUM>, the material of the conductive transport layer <NUM> may be provided as having an absorption coefficient to the incident light less than the absorption coefficient of the conductive transport layer <NUM> to the incident light, so that the absorption capability of the conductive transport layer <NUM> to the incident light is reduced while the lateral transport capability of carriers is improved, thereby improving the utilization of the photovoltaic cell to the incident light.

In some embodiments, a plurality of conductive transport layers <NUM> are provided, and the plurality of conductive transport layers <NUM> are arranged at intervals along the second direction X. A plurality of conductive transport layers <NUM> are disposed between two adjacent doped conductive layers <NUM> so that the majority carriers in the substrate <NUM> are able to be transported into the doped conductive layers <NUM> through the plurality of conductive transport layers <NUM>, thereby enhancing the lateral transport capability of the majority carriers in the substrate <NUM>. In addition, the plurality of conductive transport layers <NUM> are arranged at intervals, i.e., the conductive transport layers <NUM> are disposed not in the entire region between the two adjacent doped conductive layers <NUM>, but in partial regions between the two adjacent doped conductive layers <NUM>. In this way, when the material of the conductive transport layer <NUM> is the same as the material of the doped conductive layer <NUM>, an overall area of the conductive transport layers <NUM> is not excessively large, so that low utilization of the substrate <NUM> to the incident light due to the excessively strong absorption capability of the conductive transport layers <NUM> to the incident light is avoided.

In some embodiments, the plurality of conductive transport layers <NUM> are arranged in an array, which include a plurality of rows of conductive transport layers <NUM> arranged at intervals along a first direction Y. Each row of conductive transport layers <NUM> include a plurality of conductive transport layers <NUM> arranged at intervals along a second direction X, and at least one first electrode <NUM> is disposed between two adjacent rows of conductive transport layers <NUM> along the first direction Y. That is, in some embodiments, when only one first electrode <NUM> is disposed between two adjacent conductive transport layers <NUM>, there is a conductive transport layer <NUM> between every two adjacent first electrodes <NUM>. In some embodiments, a plurality of first electrodes <NUM> may be provided between two adjacent rows of conductive transport layers <NUM>, such that a part of two adjacent first electrodes <NUM> have a conductive transport layer <NUM> therebetween and a part of two adjacent first electrodes <NUM> do not have a conductive transport layer <NUM> therebetween. For example, in the second direction X, there is a conductive transport layer <NUM> between a <NUM>st first electrode <NUM> and a <NUM>nd first electrode <NUM>, and there is no conductive transport layer <NUM> between the <NUM>nd first electrode <NUM> and a <NUM>rd first electrode <NUM>. It should be understood that when the material of the conductive transport layer <NUM> is the same as the material of the doped conductive layer <NUM>, the more the number of the conductive transport layers <NUM>, the stronger the absorption capability of the incident light while enhancing the lateral transport capability of the carriers. Therefore, the connection relationship between the conductive transport layers <NUM> and the doped conductive layers <NUM> is flexibly set based on a total number of the first electrodes <NUM> and the demand for the current collection capability of the first electrodes <NUM>, so that the conductive transport layers <NUM> do not have strong absorption of the incident light while improving the carrier transport capability.

Referring to <FIG>, in some embodiments, there is a conductive transport layer <NUM> between every two adjacent first electrodes <NUM>. By providing the conductive transport layer <NUM> between each two adjacent first electrodes <NUM>, the lateral transport capability between adjacent first electrodes <NUM> is improved, thereby improving the current collecting capability of each first electrode <NUM>.

In some embodiments, each conductive transport layer <NUM> in a row corresponds to a respective conductive transport layer <NUM> in an adjacent row, and the two conductive transport layers <NUM> corresponding to each other are arranged at intervals along the first direction Y. For example, each conductive transport layer <NUM> in a first row is aligned with a corresponding conductive transport layer <NUM> in a second row in the first direction Y, and each row of conductive transport layers <NUM> are arranged regularly. In this way, the number of conductive transport layers <NUM> is large, thereby forming a large number of lateral transport channels for lateral transport of carriers in the substrate <NUM>. Moreover, since each row of conductive transport layers <NUM> are arranged regularly, the process of forming the conductive transport layers <NUM> is simplified in actual preparation process.

In some embodiments, a plurality of conductive transport layers <NUM> in a row are misaligned with a plurality of conductive transport layers <NUM> in an adjacent row in the second direction X. For example, each of a first row of conductive transport layers <NUM> is misaligned with each of a second row of conductive transport layers <NUM> in the first direction Y, i.e., each of the first row of conductive transport layers <NUM> is staggered with each of the second row of conductive transport layers <NUM> in the second direction X. The plurality of conductive transport layers <NUM> are arranged to be staggered so that, on the one hand, the number of the conductive transport layers <NUM> is not excessive, thereby avoiding the conductive transport layers <NUM> from absorbing too much incident light; on the other hand, the conductive transport layers <NUM> are able to be uniformly disposed on the first surface of the substrate <NUM> while the number of the conductive transport layers <NUM> is set to be small, so that the lateral transport capability of carriers at different positions in the substrate <NUM> is enhanced.

In some embodiments, in the second direction X, the density of the conductive transport layers <NUM> near the edge of the substrate <NUM> is greater than the density of the conductive transport layers <NUM> away from the edge of the substrate <NUM>, e.g., the space in the second direction X between two adjacent conductive transport layers <NUM> near the edge of the substrate <NUM> is smaller than the space in the second direction X between two adjacent conductive transport layers <NUM> away from the edge of the substrate <NUM>. In this way, the density of the conductive transport layers <NUM> near the edge of the substrate <NUM> is greater than the density of the conductive transport layers <NUM> away from the edge of the substrate <NUM>, that is, the lateral transport capability of the carriers near the edge of the substrate <NUM> is stronger, so that the concentration of carriers in the first electrodes <NUM> near the edge of the substrate <NUM> is larger, thereby compensating for the number of carriers collected by outermost second electrodes <NUM>, and improving the capability of the outermost second electrodes <NUM> to collect current.

In some embodiments, a top surface of a respective conductive transport layer <NUM> is lower than or flush with a top surface of a respective doped conductive layer <NUM>. By providing the top surface of the conductive transport layer <NUM> to be not higher than the top surface of the doped conductive layer <NUM>, the problem of the incident light on side walls of the conductive transport layer <NUM> due to the top surface of the conductive transport layer <NUM> protruding from the top surface of the doped conductive layer <NUM> is prevented, thereby reducing the parasitic absorption capability of the conductive transport layer <NUM> to the incident light. A height of the conductive transport layer <NUM> may be <NUM> to <NUM> times a height of the doped conductive layer <NUM> in a direction perpendicular to the surface of the substrate <NUM>.

In some embodiments, referring to <FIG>, a doping element type of the doped conductive layer <NUM> is the same as a doping element type of the doped layer <NUM>. A doping concentration of the doped layer <NUM> is less than that of the doped conductive layer <NUM>. A high-low junction is formed between the doped layer <NUM> and the substrate <NUM>, and a first built-in electric field is formed between the doped layer <NUM> and the substrate <NUM>. A high-low junction is formed between the doped layer <NUM> and the doped conductive layer <NUM>, a second built-in electric field is formed between the doped layer <NUM> and the doped conductive layer <NUM>, and directions of voltages of the first built-in electric field and the second built-in electric field are the same, so that a double voltage difference is formed. Majority carriers tending to the internal of the substrate <NUM> are easily drift to the doped layer <NUM> that is highly doped, and then drift to the doped conductive layer <NUM>, and finally collected by the first electrode <NUM>, which is conducive to increasing an output current of the cell. Meanwhile, due to the presence of the built-in electric fields, a barrier exists between the substrate <NUM> and the doped layer <NUM>, and a barrier exists between the doped layer <NUM> and the doped conductive layer <NUM>, thereby blocking the drift of the majority carriers in the highly-doped layers to the low-doped substrate <NUM>.

Similarly, referring to <FIG>, a doping element type of the conductive transport layer <NUM> is the same as the doping element type of the doped layer <NUM>. A doping concentration of the conductive transport layer <NUM> is greater than the doping concentration of the doping layer <NUM>. A high-low junction is formed between the doped layer <NUM> and the conductive transport layer <NUM>, a third built-in electric field is formed between the doped layer <NUM> and the conductive transport layer <NUM>, and directions of voltages of the first built-in electric field and the third built-in electric field are the same, so that a double voltage difference is formed. Majority carriers tending to the internal of the substrate <NUM> are easily drift to the doped layer <NUM> that is highly doped, and then drift to the conductive transport layer <NUM>, and further drift to the doped conductive layer <NUM>, and finally collected by the first electrode <NUM>, which is conducive to increasing the output current of the cell. Meanwhile, the presence of the built-in electric fields prevents the majority carriers in the highly-doped layers from drifting to the low-doped substrate <NUM>.

<FIG> is still another partial and cross-sectional schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure.

In some embodiments, referring to <FIG>, a conductive transport layer <NUM> includes body portions <NUM> arranged at intervals and a connection portion <NUM> between the adjacent body portions <NUM> in the first direction Y, the body portions <NUM> are in contact with side walls of the respective two adjacent doped conductive layers <NUM>, and a doping concentration of the body portion <NUM> is less than or equal to a doping concentration of the connection portion <NUM>. Since the conductive transport layer <NUM> serves as a lateral transport channel for carriers, a concentration of carriers in portions (i.e., the body portions <NUM>) of a conductive transport layer <NUM> adjacent to the doped conductive layers <NUM> is relatively high, so that portions of the doped conductive layers <NUM> adjacent to the body portions <NUM> also have a relatively high carrier concentration, and therefore the current collecting capability of the first electrode <NUM> is improved. Meanwhile, the doping concentration at the connection portion <NUM> is relatively small, and the light absorption is relatively weak, so that the conductive transport layer <NUM> is avoided from absorbing too much incident light, thereby improving the photoelectric conversion performance of the photovoltaic cell as a whole.

In some embodiments, a ratio of a total area of connection portions <NUM> in the plurality of conductive transport layers <NUM> to an area of a conductive transport layer <NUM> is in a range of <NUM>:<NUM> to <NUM>:<NUM>, and optionally, the ratio of the total area of the connection portion <NUM> to the area of the conductive transport layer <NUM> is in range of <NUM>/<NUM> to <NUM>/<NUM>, in particular <NUM>, <NUM>, <NUM>, <NUM>, etc. The larger area proportion of the body potions <NUM> enhances the current collecting ability of the first electrode <NUM>, reduces the absorption of light, and improves the cell efficiency. When the area proportion of the connecting portion <NUM> is larger, the lateral transmission capability of the carriers is improved.

In some embodiments, a top surface of a connection portion <NUM> has a light trapping structure. The light trapping structure may enhance the reflectivity of the top surface of the conductive transport layer <NUM> to the incident light, so that the incident light irradiated to the top surface of the conductive transport layer <NUM> may be reflected away, preventing absorption by the conductive transport layer <NUM>. This portion of the reflected incident light may also be reflected back, for example, to regions that are not covered by the doped conductive layer <NUM> and the conductive transport layer <NUM>, thereby being absorbed and utilized by the substrate <NUM>, so that the absorption and utilization of the incident light by the substrate <NUM> are enhanced.

In some embodiments, a cross-sectional shape of the connection portion <NUM> in a direction perpendicular to the first surface includes a triangular shape, a rectangular shape, a trapezoidal shape, or an elliptical shape, and the top surface of the connection portion <NUM> is lower than the top surface of the body portion <NUM>, so that the doped conductive layer <NUM> has a certain shielding effect on the incident light irradiated to the top surface of the conductive transport layer <NUM>. In addition, the incident light is also reflected for multiple times on side walls of the connection portion <NUM>, thereby reducing parasitic absorption of the top surface of the conductive doped layer <NUM> to the incident light. It should be appreciated that, in some embodiments, the cross-sectional shape of the connecting portion <NUM> may include other shapes, as long as the top surface of the connecting portion is recessed toward the substrate <NUM>.

In some embodiments, a second doping region <NUM> includes first sub-doping portions <NUM> arranged at intervals and a second sub-doping portion <NUM> between the adjacent first sub-doping portions <NUM>, each first sub-doping portion <NUM> is aligned with a respective body portion <NUM>, and the second sub-doping portion <NUM> is aligned with the connection portion <NUM>. A doping concentration of the first sub-doping portion <NUM> is less than or equal to the doping concentration of the second sub-doping portion <NUM>. A total doping amount of the first sub-doping portions <NUM> is less than or equal to a total doping amount of the second sub-doping portion <NUM>. The total doping amount of the first sub-doped portion <NUM> being less than or equal to the total doping amount of the second sub-doped portion <NUM> includes that the doping concentration of the first sub-doped portion <NUM> is less than or equal to the doping concentration of the second sub-doped portion <NUM> or a doping depth of the first sub-doped portion <NUM> is less than or equal to a doping depth of the second sub-doped portion <NUM> in a direction perpendicular to the first surface, alternatively, includes that the doping concentration of the first sub-doping portion <NUM> is less than or equal to the doping concentration of the second sub-doping portion <NUM> and the doping depth of the first sub-doping portion <NUM> is less than or equal to the doping depth of the second sub-doping portion <NUM>. The connection portion <NUM> is located between adjacent body portions <NUM>, the body portions <NUM> are directly in contact with the side walls of the doped conductive layers <NUM>, the conductive transport layer <NUM> is configured to enhance the transport capability of the cell, and the low doping of the first sub-doping portion <NUM> aligned with the body portion <NUM> is able to avoid the high doping effect (e.g., the tunneling effect generates the composite current). The high doping of the second sub-doping portion <NUM> aligned with the connection portion <NUM> is able to increase the transmission rate of carriers.

In some embodiments, the photovoltaic cell further includes a passivation layer <NUM> disposed on surfaces of the doped conductive layers <NUM>, the conductive transport layers <NUM> and the third doped regions <NUM>. The passivation layer <NUM> may be considered a rear passivation layer. The passivation layer <NUM> may include a single layer structure or a stacked layer structure, and the material 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, etc..

The first electrode <NUM> includes a grid line of the photovoltaic cell for collecting and aggregating current of the photovoltaic cell. The first electrode <NUM> may be sintered from a burnthrough-type slurry. The material of the first electrode <NUM> may include one or more of aluminum, silver, gold, nickel, molybdenum, copper, etc. In some embodiments, the first electrode <NUM> refers to a fine grid line or finger grid line to distinguish from a main grid line or bus bar.

In some embodiments, the photovoltaic cell further includes an emitter disposed on a second surface of the substrate <NUM> away from the doped layer <NUM>, a first passivation layer disposed on a surface of the emitter away from the substrate <NUM>, and a plurality of electrodes spaced apart. A doping element type of the emitter is different from the doping element type of the substrate <NUM>, the first passivation layer is regarded as a front passivation layer, and the plurality of electrodes penetrate through the first passivation layer and are in contact with the emitter.

In some embodiments, the first passivation layer may include a single layer structure or a stacked layer structure, and the material of the first passivation layer may include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, aluminum oxide, etc..

The plurality of electrodes are sintered from a burnthrough-type slurry. The contact between the electrodes and the emitter may be local or full contact. The material of the electrodes may be one or more of aluminum, silver, nickel, gold, molybdenum, copper, etc. In some embodiments, the electrodes are upper electrodes or front electrodes. In some embodiments, the electrodes refer to fine grid lines or finger grid lines to distinguish from the main grid line or bus bar.

In some embodiments, an antireflection layer for antireflection of the incident light may be provided on the surface of the emitter away from the substrate <NUM>. In some embodiments, the antireflection layer may be a silicon nitride layer, and the silicon nitride layer may include a silicon nitride material. In some embodiments, the antireflection layer may also be provided as a multilayer structure, for example, a stacked structure which may be composed of one or more of silicon nitride, silicon oxide, or silicon oxynitride.

In some embodiments, the second surface of the substrate <NUM> may also have a structure similar to the first surface of the substrate <NUM>, for example, a second tunneling dielectric layer and a second doped conductive layer may be sequentially stacked on the second surface of the substrate <NUM> in a direction away from the second surface of the substrate <NUM>. A type of doping ions in the second doped conductive layer is different from the type of doping ions in the doped conductive layer <NUM>.

<FIG> is another schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is another schematic structural diagram of a doped layer in a photovoltaic cell according to an embodiment of the present disclosure. <FIG> is still yet another partial and cross-sectional schematic structural diagram of a photovoltaic cell according to an embodiment of the present disclosure.

In some embodiments, the photovoltaic cell further includes a plurality of second electrodes <NUM> arranged at intervals along the second direction X. The second electrodes <NUM> extend along the first direction Y and are electrically connected to the plurality of first electrodes <NUM> disposed at intervals along the first direction Y for collecting current in the first electrodes <NUM> for collection and exporting the current from the photovoltaic cell. It should be understood that the second electrodes <NUM> are in electrical contact not only with the first electrodes <NUM> but also with partial doped conductive layers <NUM> so that carriers in the doped conductive layers <NUM> are able to be directly transmitted into the second electrodes <NUM> without passing through the first electrodes <NUM>, which improves the ability of the second electrode <NUM> to collect current.

In some embodiments, at least one conductive transport layer <NUM> is disposed between two adjacent second electrodes <NUM>, i.e., the second electrodes <NUM> are interleaved with the conductive transport layers <NUM>. In this way, positions of the second electrodes <NUM> are limited by the conductive transport layers <NUM>, so that the positions of the second electrodes <NUM> are determined without performing additional positioning processing during preparing the second electrodes <NUM>, thereby facilitating printing of the second electrodes <NUM> and simplifying the process flow. The photovoltaic cell further includes a plurality of conductive connection layers <NUM> each disposed between the conductive transmission layer <NUM> and the second electrode <NUM>, opposite side walls of the conductive connection layer <NUM> are in contact with a side wall of the conductive transmission layer <NUM> and a side wall of the second electrode <NUM>, respectively, so that the second electrode <NUM> is able to collect the current of the substrate <NUM> through the doped conductive layer <NUM> without passing through the first electrode <NUM>. In some embodiments, as shown in <FIG>, the conductive connection layer <NUM> may also be disposed between two adjacent conductive transmission layers <NUM>, and the opposite side walls of the conductive connection layer <NUM> are in contact with a side wall of one of the two adjacent conductive transmission layers <NUM> and a side wall of the other of the two adjacent conductive transmission layers <NUM>.

In some embodiments, the doped layer <NUM> further includes a plurality of fourth doped regions <NUM> each aligned with a respective conductive connection layer <NUM>, and a doping concentration of the fourth doped region is greater than or equal to the doping concentration of the first doped region <NUM> and less than or equal to the doping concentration of the third doped region <NUM>. The technical effect that the doping concentration of the fourth doping region <NUM> is greater than or equal to the doping concentration of the first doping region <NUM> and less than or equal to the doping concentration of the third doping region <NUM> is similar to the technical effect that the doping concentration of the first doping region <NUM> is less than the doping concentration of the second doping region <NUM> and less than the doping concentration of the third doping region <NUM>, which is not repeated herein.

A doping depth of the fourth doped region <NUM> is greater than or equal to the doping depth of the first doped region <NUM> and less than or equal to the doping depth of the third doped region <NUM>. The technical effect that the doping depth of the fourth doping region <NUM> is greater than or equal to the doping depth of the first doping region <NUM> and less than or equal to the doping depth of the third doping region <NUM> is similar to the technical effect that the doping depth of the first doping region <NUM> is less than the doping depth of the second doping region <NUM> and less than the doping depth of the third doping region <NUM>, which is not repeated herein.

Some embodiments of the present disclosure further provide a photovoltaic module including at least one cell string, each of the at least one cell string formed by a plurality of photovoltaic cells according to the above embodiments which are electrically connected; at least one encapsulation layer, each of the at least one encapsulation layer configured to cover a surface of a respective cell string; and at least one cover plate, each of the at least one cover plate configured to cover a surface of a respective encapsulation layer facing away from the respective cell string.

In the embodiments of the present disclosure, the doped layer <NUM> is disposed on the surface of the substrate <NUM>, and the doped layer <NUM> includes the plurality of first doped regions <NUM>, the plurality of second doped regions <NUM> and the plurality of third doped regions <NUM>. A respective doped conductive layer <NUM> and a respective first electrode <NUM> are disposed in each first doped region <NUM>, a respective conductive transport layer <NUM> is disposed in each second doped region <NUM>, and no first electrode <NUM> and doped conductive layer <NUM> is disposed in each third doped region <NUM>. In order to improve the contact between the doped conductive layers <NUM> and the first electrodes <NUM>, the doped conductive layers <NUM> are usually configured to be highly doped. In the embodiments of the present disclosure, the doping concentration of each first doped region <NUM> is less than the doping concentration of each second doped region <NUM> and less than the doping concentration of each third doped region <NUM>. On the one hand, the decrease of the band gap of the substrate <NUM> due to the excessive concentration of the doping elements below the first electrode <NUM> is avoided, so that the reduction of the open-circuit voltage of the photovoltaic cell and the decay of the electric field are avoided. On the other hand, a high doping effect (e.g., a tunneling effect produces a composite current) caused by an excessive doping concentration of the doped conductive layers <NUM> and the excessive doping concentration of the doped layer <NUM> is avoided. However, by providing the plurality of second doping regions <NUM> and the plurality of third doping regions <NUM> with large doping concentrations, the carrier transporting efficiency in the region unaligned with the first electrodes <NUM> is improved, so that the open-circuit voltage of the photovoltaic cell is increased, which is conducive to improving the photoelectric conversion efficiency of the photovoltaic cell.

<FIG> is a schematic structural diagram of a photovoltaic module according to an embodiment of the present disclosure.

Embodiments of the present disclosure further provides a photovoltaic module. As shown in <FIG>, the photovoltaic module includes at least one cell string, each of the at least one cell string formed by a plurality of photovoltaic cells <NUM> according to the above embodiments which are electrically connected; at least one encapsulation layer <NUM>, each of the at least one encapsulation layer <NUM> configured to cover a surface of a respective cell string; and at least one cover plate <NUM>, each of the at least one cover plate <NUM> configured to cover a surface of a respective encapsulation layer facing away from the respective cell string. The photovoltaic cells <NUM> are electrically connected in whole or in pieces to form a plurality of cell strings electrically connected in series and/or in parallel.

Specifically, in some embodiments, the plurality of cell strings may be electrically connected to each other by conductive tapes. The at least one encapsulation layer <NUM> includes a first encapsulation layer <NUM> and a second encapsulation layer <NUM>, the first encapsulation layer <NUM> covers one of the front surface and the rear surface of the photovoltaic cell <NUM>, and the second encapsulation layer <NUM> covers the other of the front surface and the rear surface of the photovoltaic cell <NUM>. Specifically, at least one of the first encapsulation layer <NUM> and the second encapsulation layer <NUM> may be an organic encapsulation adhesive film such as an ethylene-vinyl acetate copolymer (EVA) adhesive film, a polyethylene octene co-elastomer (POE) adhesive film, a polyethylene terephthalate (PET) adhesive film, or the like. In some embodiments, the cover plate <NUM> may be a glass cover plate, a plastic cover plate, or the like having a light transmitting function. Specifically, the surface of the cover plate <NUM> facing towards the encapsulation layer <NUM> may be a concavo-convex surface, thereby increasing utilization of the incident light. The at least one cover plate <NUM> includes a first cover plate <NUM> and a second cover plate <NUM>. The first cover plate <NUM> is with respect to the first encapsulation layer <NUM>, and the second cover plate <NUM> is with respect to the second encapsulation layer <NUM>.

Although the present disclosure is disclosed in the above embodiments, the present disclosure is not intended to limit the claims. Any person skilled in the art may make several possible changes and modifications without departing from the concept of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the scope defined in the claims of the present disclosure. In addition, the embodiments and the accompanying drawings of the present disclosure are illustrative only and are not the full protection scope of the claims.

Claim 1:
A photovoltaic cell comprising:
a substrate (<NUM>);
a doped layer (<NUM>) disposed in a portion of the substrate adjacent to a first surface of the substrate, wherein a doping element type of the doped layer is the same as a doping element type of the substrate, and a doping concentration of the doped layer is greater than a doping concentration of the substrate, wherein the doped layer includes a plurality of first doped regions (<NUM>) arranged at intervals along a first direction (Y), a plurality of second doped regions (<NUM>) disposed between respective two adjacent first doped regions and a plurality of third doped regions (<NUM>) disposed between the respective two adjacent first doped regions, and wherein a doping concentration of each of the plurality of first doped regions is less than a doping concentration of any of the plurality of second doped regions and less than a doping concentration of any of the plurality of third doped regions;
at least one tunneling dielectric layer (<NUM>) disposed on the plurality of first doped regions and the plurality of second doped regions;
a plurality of doped conductive layers (<NUM>) arranged at intervals along the first direction, wherein each of the plurality of doped conductive layers is aligned with a respective first doped region and is disposed on a respective tunneling dielectric layer;
a plurality of first electrodes (<NUM>) arranged at intervals along the first direction, wherein the plurality of first electrodes extend in a second direction (X), each of the plurality of first electrodes is disposed on a side of a respective doped conductive layer away from the substrate and electrically connected to the respective doped conductive layer; and
a plurality of conductive transport layers (<NUM>) each aligned with a respective second doped region, wherein the plurality of conductive transport layers are disposed on the at least one tunneling dielectric layer, and each of the plurality of conductive transport layers is disposed between respective two adjacent doped conductive layers and is in contact with side walls of the respective two adjacent doped conductive layer so that the majority carriers in the substrate (<NUM>) are able to be transported into the doped conductive layers (<NUM>) through the plurality of conductive transport layers (<NUM>), thereby enhancing the lateral transport capability of the majority carriers in the substrate (<NUM>).