Back-contact solar cell and cell assembly

Abstract

Back-contact solar cell, characterized in that it comprises: a substrate having a substrate front and a substrate back that are opposite each other, wherein the substrate front faces a main light-receiving area of ​​the cell and the substrate back faces a non-main light-receiving area of ​​the cell, and wherein the doping type of the substrate is an N-type; a P-type polarity region comprising a first doped semiconductor layer; an N-type polarity zone comprising a second doped semiconductor layer, wherein the N-type polarity zone and the P-type polarity zone are alternately provided on a side located on the back of the substrate, wherein the second doped semiconductor layer has a smaller thickness in a normal direction of the cell than the thickness of the first doped semiconductor layer in the normal direction, and wherein the P-type polarity zone has a greater width in an extension direction of the cell that extends perpendicular to the normal direction than the width of an adjacent N-type polarity zone in the extension direction; and an isolation zone located between any two adjacent N-type polarity zones and P-type polarity zones.

Description

Technical area

[0001] The present application relates mainly to the field of crystalline silicon solar cells, in particular to a back contact solar cell and a cell assembly. State of the art

[0002] The constant pursuit of efficiency improvement and cost reduction is the trend in the photovoltaic industry. Conventional PERC (passivated emitter and rear cell) cells are approaching the theoretical limit of their conversion efficiency, leaving little room for cost reduction. However, the market's drive for higher photoelectric conversion efficiency remains unabated. Therefore, the field is urgently seeking the next generation of efficient technology. Mainstream technologies currently being developed include tunnel oxidation passivation contact cells (TOPC), heterojunction cells (HJT), and back contact cells (IBC).

[0003] In the IBC cell, metal electrodes are located on the back of the cell, while there are no metal electrodes on the front, leading to the cover. This improves the luminous efficacy and achieves a higher short-circuit current. However, improving the design details of existing back-contact cells to further increase photoelectric conversion efficiency has long been an important topic of ongoing research in this field. Disclosure of the invention

[0004] The technical problem to be solved by the present application is to provide a back-contact solar cell and a cell assembly that can take into account the electrical and optical performances of the solar cell and further improve the short-circuit current, the open-circuit voltage and the photoelectric conversion efficiency of the solar cell.

[0005] To solve the technical problem, the present application provides a back-contact solar cell comprising: a substrate having a substrate front side and a substrate back side that are opposite each other, the substrate front side facing a main light-receiving surface of the cell and the substrate back side facing a non-main light-receiving surface of the cell; a P-type polarity region comprising a first doped semiconductor layer; an N-type polarity region comprising a second doped semiconductor layer, the N-type polarity region and the P-type polarity region being alternately provided on a side facing the substrate back side, the second doped semiconductor layer having a smaller thickness in a normal direction of the cell than the thickness of the first doped semiconductor layer in the normal direction; and an insulation region located between every two adjacent N-type polarity regions and P-type polarity regions.

[0006] Optionally, it is provided that the doping type of the first doped semiconductor layer is a P-type doping and doped impurities comprise boron atoms and / or boron-containing compounds; and that the doping type of the second doped semiconductor layer is an N-type doping and doped impurities comprise phosphorus atoms and / or phosphorus-containing compounds.

[0007] Optionally, the thickness of the first doped semiconductor layer is in the range of 15 to 500 nm and the thickness of the second doped semiconductor layer is in the range of 10 to 400 nm.

[0008] Optionally, the thickness of the second doped semiconductor layer is 30 to 150 nm thinner than the thickness of the first doped semiconductor layer.

[0009] Optionally, the P-type polarity region has a greater width in an extension direction of the cell extending perpendicular to the normal direction than the width of the one adjacent N-type polarity region in the extension direction when the conductivity type of the substrate and the conductivity type of the P-type polarity region are opposite; and the N-type polarity region has a greater width in the extension direction than the width of the one adjacent P-type polarity region in the extension direction when the conductivity type of the substrate and the conductivity type of the P-type polarity region are the same.

[0010] Optionally, the width of the isolation zone in the extension direction is less than the width of each P-type polarity zone or each N-type polarity zone in the extension direction.

[0011] Optionally, the substrate further comprises a first doped substrate layer at a location corresponding to the P-type polarity zone, which layer is adjacent to the substrate backside in the substrate.

[0012] Optionally, the P-type polarity zone further comprises a first doped oxide layer having a thickness in the range of 0.5 to 3 nm and adjoining a side of the first doped semiconductor layer facing the substrate backside.

[0013] Optionally, the P-type polarity zone further comprises a first doped substrate layer adjoining the substrate backside, wherein the first doped oxide layer adjoins a side of the first doped substrate layer facing away from the substrate backside.

[0014] Optionally, the substrate further comprises a second doped substrate layer at a location corresponding to the N-type polarity zone, which second doped substrate layer adjoins the substrate backside in the substrate.

[0015] Optionally, the N-type polarity zone further comprises a second doped oxide layer having a thickness in the range of 0.5 to 3 nm and adjoining a side of the second doped semiconductor layer facing the substrate backside.

[0016] Optionally, the N-type polarity zone further comprises a second doped substrate layer adjoining the substrate backside, wherein the second doped oxide layer adjoins a side of the second doped substrate layer facing away from the substrate backside.

[0017] Optionally, it is further provided that a passivated back layer is included, which is located in the substrate back side on an outermost layer of the N-type polarity zone, the P-type polarity zone, and the insulation zone facing away from the substrate back side. Optionally, it is provided that the passivated back layer comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, or a stacked media layer consisting of two or more thereof.

[0018] Optionally, the back contact solar cell further comprises a first electrode and a second electrode, which are located in the P-type polarity zone and the N-type polarity zone, respectively, wherein the first electrode and the second electrode each pass through the passivated back layer and are brought into contact with the first doped semiconductor layer and the second doped semiconductor layer.

[0019] Optionally, the back contact solar cell further comprises a passivated front layer located on a side facing the substrate front side, wherein the passivated front layer comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, magnesium fluoride, or a stacked media layer consisting of two or more thereof.

[0020] Optionally, the substrate further comprises a front surface field adjacent to the substrate front side, wherein the doping type of the front surface field is the same as the doping type of the substrate and the front surface field has a higher doping concentration than that of the substrate.

[0021] To solve the technical problem, the present application provides a cell assembly comprising a plurality of the above-mentioned back contact solar cells connected in series and / or parallel.

[0022] Compared to the prior art, the back contact cell optimized in design detail allows the electrical and optical performance of the solar cell to be taken into account and the short-circuit current, the open-circuit voltage and the photoelectric conversion efficiency of the solar cell to be further improved by setting different polarity zones on the back of the cell to specific widths and thicknesses with differentiations for the back contact (IBC) solar cell based on characteristic layers with good passivation effect in the present application. Short description of the characters

[0023] For a better understanding, the drawings are included, which form a part of the present application. The drawings show the embodiments of the present application and, together with the description, explain the principle of the present application. It shows: Fig. 1 a schematic structural representation of a back contact solar cell according to an embodiment of the present application. Detailed embodiments

[0024] To further explain the technical solutions of the embodiments of the present application, the drawings required for describing the embodiments are briefly summarized below. Of course, the following drawings merely illustrate some examples or embodiments of the present application, and based on these drawings, a person of ordinary skill in the art can also apply the present application to other similar scenarios without inventive activity. Unless otherwise indicated or understood by the context, the same reference numerals in the figures represent the same structures or operations.

[0025] As indicated in the present application and claims, the terms "a" and / or "an" and / or "the" do not necessarily refer to the singular form, but may include the plural form unless the context clearly indicates otherwise. Generally, the terms "comprising" and "including" encompass only the clearly stated steps and elements, which are not an exclusive list, so the method or device may also include another step or element.

[0026] Unless otherwise indicated, the relative arrangement, numerical designation, and values ​​of the components and steps discussed in the exemplary embodiments are not intended to limit the scope of the application. Furthermore, it is to be understood that in the figures, the individual parts are not drawn to scale for convenience of description. The technologies, methods, and devices known to those of ordinary skill in the art would not be discussed in detail, but should be considered a part of the description where appropriate. In all examples shown and discussed herein, a specific value is intended to be exemplary, not limiting. Therefore, a different value may be specified in a different example of the exemplary embodiment.It should be noted that in the figures the similar numbers and symbols mean the similar objects, and that an object need not be discussed further if it is already defined in a previous figure.

[0027] It should be understood that, in the context of the description of the present application, the direction or positioning designated by the positional terms "in front," "behind," "top," "bottom," "left," "right," as well as "lateral," "longitudinal," "vertical," "horizontal," and "top," "bottom," etc., are generally used with reference to the direction or positioning shown in the respective figure, solely to describe the present application and to simplify the description. Unless otherwise stated, these positional terms neither implicitly nor explicitly indicate the positioning, design, and operation of the device or element in question in a predetermined position, and therefore do not constitute a limitation of the application. The directional terms "inner," "outer," mean the inside and outside with respect to the profile of a part itself.

[0028] For ease of description, terms of relative spatial relationship, such as "over," "upper," "on top," "on," etc., may be used herein to describe the spatial positional relationship of one means or feature to another means or feature in the figure. It is to be understood that these terms of relative spatial relationship are intended to include other positions in use or operation in addition to the position shown in the figure. For example, if the means is reversed in the figure, a means previously described as "above another means or component" or "over another means or component" will now be positioned as "below another means or component" or "below another means or component." Thus, the exemplary term "over" can encompass both the positions of "above" and "below."The agent may, of course, be positioned in other ways, such as rotated by 90 degrees or in yet another position, and the spatial description used herein shall be constructed accordingly.

[0029] It should also be noted that the use of the words "first", "second", etc. is only for distinguishing between the respective parts, and these words do not imply any particular meaning unless otherwise stated. Therefore, they should not be construed as limiting the scope of the present application. Although the terms used in the present application have been selected from generally known terms, the selection of some terms in the description of the present application was based on the applicant's determination, and the specific meaning can be derived from corresponding parts of the present description. Furthermore, the present application should be understood not only by the specific terms used, but also by the meaning of individual terms.

[0030] In relation to Fig. Figure 1 shows a schematic structural diagram of a back-contact solar cell 10 (hereinafter referred to as cell 10) according to the present application. The cell 10 mainly comprises a substrate 101, a P-type polarity region 102, an N-type polarity region 103, and an insulating region 104. Specifically, the substrate 101 has a substrate front side 1011 and a substrate back side 1012 that are opposite each other, with the substrate front side 1011 facing a main light-receiving surface of the cell 10. The light direction S in Fig. 1 indicates that the top surface of cell 10, which is arranged in the manner shown in Fig. 1, represents the main light-receiving surface. Specifically, the substrate front side 1011 typically has a textured structure, including pyramid texture and / or corrosion pit texture. Accordingly, the substrate back side 1012 faces a non-main light-receiving surface of the cell 10, which, for example, has a polished surface structure, including conventional alkaline polishing surfaces, etc.

[0031] Furthermore, it is provided that the above-mentioned P-type polarity zone 102 in this embodiment comprises a first doped semiconductor layer 1021. In this embodiment, it is preferred that the thickness of the first doped semiconductor layer 1021 be in the range of 15 to 500 nm, preferably 150 to 250 nm, 250 to 350 nm, 350 to 450 nm, or 50 to 150 nm, and can be freely adjusted depending on the actual manufacturing situation. The doping type of the first doped semiconductor layer 1021 is a P-type doping, and doped impurities include P-type doped polysilicon with boron atoms and / or boron-containing compounds, etc.

[0032] Based on this, the N-type polarity zone 103 comprises a second doped semiconductor layer 1031. In this embodiment, it is preferred that the thickness of the second doped semiconductor layer 1031 be in the range of 10 to 400 nm, preferably 100 to 200 nm, 200 to 300 nm, 300 to 400 nm, or 40 to 140 nm. The doping type of the second doped semiconductor layer 1031 is an N-type doping, and doped impurities include phosphorus atoms and / or phosphorus-containing compounds.

[0033] It is preferred that in several embodiments according to Fig. 1 according to the present application, the thickness of the second doped semiconductor layer 1031 is 30 to 150 nm thinner than the thickness of the first doped semiconductor layer 1021, wherein the thickness difference is more preferably 50 nm, 100 nm or any value between 50 nm and 100 nm.

[0034] In Fig. 1 only shows a portion of the construction of cell 10. However, it should be understood that in this embodiment, N-type polarity region 103 and P-type polarity region 102 are provided alternately on a side facing the substrate backside 1012, and that an insulating region 104 is provided between each two adjacent N-type polarity regions 103 and P-type polarity regions 102. For example, insulating region 104 may have a textured structure and / or a polished surface structure. N-type polarity region 103 and P-type polarity region 102 have opposite conductive polarities. The insulating region 104 provided therebetween can prevent the establishment of an electrical connection between the positive and negative poles of cell 10, which would cause a short circuit.

[0035] In this embodiment, it is preferable that the thickness of the second doped semiconductor layer 1031 in a normal direction x of the cell 10 is smaller than the thickness of the first doped semiconductor layer 1021 in the normal direction. Specifically, the doping type of the P-type polarity region 102 is P-type doping, and doped impurities include boron atoms and / or boron-containing compounds. Therefore, doped impurities have lower solid solubility in silicon and are thus more difficult to dope, so a thicker doped layer is required to reduce the sheet resistance. In contrast, the doping type of the N-type polarity region 103 is N-type doping and is easy to dope.Therefore, in the cell 10, based on the above technical perspective, it is preferable to reduce the thickness of the N-type polarity region 103 (particularly the second doped semiconductor layer 1031 therein) to reduce the absorption loss of incident light and increase the short-circuit current and conversion efficiency. Through the design of the cell 10, the light loss of the cell 10 can be reduced and the short-circuit current and conversion efficiency can be increased. Furthermore, the electrical and optical characteristics of the cell 10 can be considered by the thickness differences between the first doped semiconductor layer 1021 in the P-type polarity region 102 and the second doped semiconductor layer 1031 in the N-type polarity region 103.

[0036] More specifically, in the present application, the conductivity type of the substrate 101 is not unique. Furthermore, the width of the back-side polarity zone of the cell 10 is also adjusted differently depending on the conductivity type of the substrate 101. To better understand the width adjustment, any of the N-type polarity zone 103, isolation zone 104, and P-type polarity zone 102, which are adjacent and arranged one after the other on the back side of the cell 10, are considered as a polarity zone group.In this embodiment, it is preferable that the width of the P-type polarity region 102 in an extension direction y (perpendicular to the normal direction x) of the cell 10 be greater than the sum of the widths of an N-type polarity region 103 and an isolation region 104 in the extension direction y, which are adjacent to said P-type polarity region 102 and in the same polarity region group, when the conductivity type of the substrate 101 and the conductivity type of the P-type polarity region 102 are opposite. Such a case is shown in FIG. Fig. 1 shown.

[0037] On the other hand, in some variants of the embodiments with respect to Fig. 1 the width of the N-type polarity region 103 in the extension direction y is greater than the sum of the widths of a P-type polarity region 102 and an insulating region 104 in the extension direction, which are adjacent to said N-type polarity region and in the same polarity region group, when the conductivity type of the substrate 101 and the conductivity type of the P-type polarity region 102 are the same.

[0038] Specifically, a PN junction is formed on the back side of cell 10 between the polarity zone, which has an opposite conductivity type with respect to the semiconductor substrate 101, and the substrate 101. By adjusting the above-mentioned widths, the area of ​​the PN junction can be larger than the area of ​​the non-PN junction in embodiments for different conductivity types of the substrates, which promotes the separation and collection of charge carriers and thus increases the fill factor and conversion efficiency of the solar cells.

[0039] In this exemplary embodiment, the P-type polarity zone 102 further comprises a first doped oxide layer 1022, wherein the doping type of the first doped oxide layer is a P-type doping, and wherein the first doped oxide layer adjoins a side of the first doped semiconductor layer 1021 facing the substrate backside 1012. The first doped oxide layer 1022 comprises silicon oxide and aluminum oxide. The first doped oxide layer 1022 has a thickness in the range of 0.5 to 3 nm, preferably 1 to 2 nm. Furthermore, it is provided that the substrate 101 further comprises a first doped substrate layer 1023 at a location corresponding to the P-type polarity zone 102, wherein the doping type of the first doped substrate layer is a P-type doping, and wherein the first doped substrate layer in the substrate 101 adjoins the substrate backside 1012.In this embodiment, it is provided that the first doped oxide layer 1022 adjoins a side located on the substrate backside 1012 of the substrate 101, ie that it adjoins the first doped substrate layer 1023.

[0040] In relation to Fig. 1, on the other hand, the N-type polarity zone 103 further comprises a second doped oxide layer 1032 comprising silicon oxide and aluminum oxide and adjoining a side of the second doped semiconductor layer 1031 facing the substrate backside 1012. Similarly, the second doped oxide layer 1032 has a thickness in the range of 0.5 to 3 nm, preferably 1 to 2 nm. The substrate 101 further comprises, at a location corresponding to the N-type polarity zone 103, a second doped substrate layer 1033, wherein the doping type of the second doped substrate layer is an N-type doping, and wherein the second doped substrate layer in the substrate 101 adjoins the substrate backside 1012. The second doped oxide layer 1032 is adjacent to the substrate backside 1012 of the substrate 101, ie, it is adjacent to the second doped substrate layer 1023.

[0041] Specifically, assuming that the second doped semiconductor layer 1031 and the first doped semiconductor layer 1021 have opposite doping types, it is the case that the second doped substrate layer 1033 and the second doped oxide layer 1032 each have a doping type opposite to the first doped substrate layer 1023 and a doping type opposite to the first doped oxide layer 1022, and the doping types represent N-type doping, wherein N-type doped polysilicon with phosphorus atoms, phosphorus ions and / or phosphorus-containing compounds, etc. is contained therein.

[0042] Based on the above structure, the cell 10 further comprises a passivated back layer 105 located on the substrate back side 1012 on an outermost layer of the N-type polarity region 103, the P-type polarity region 102 and the insulation region 104 facing away from the substrate back side 1012 (see Fig. 1. Alternatively, the outermost layer can also be understood as an outermost side extending continuously and forming the back side of the cell 10, and the outermost side of the passivated back layer 105 also forms the non-main light-receiving surface of the cell. The passivated back layer 105 comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, or a stacked media layer consisting of two or more thereof.

[0043] In contrast, the cell 10 further comprises a passivated front layer 106 located on a side facing the substrate front side 1011, wherein the passivated front layer 106 comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, magnesium fluoride, or a stacked media layer consisting of two or more thereof.

[0044] In this embodiment, the cell 10 further comprises a plurality of first electrodes 107 located in each P-type polarity zone 102. The first electrode 107 passes through the passivated back layer 105 in the P-type polarity zone and forms an electrical contact with the first doped semiconductor layer 1021. The material of the first electrode 107 consists of a conductive metal such as silver, copper, and their compounds, etc. Similarly, the cell 10 further comprises a plurality of second electrodes 108 located in each N-type polarity zone 103. The second electrode 108 passes through the passivated back layer 105 in the N-type polarity zone and forms an electrical contact with the second doped semiconductor layer 1031. The material of the second electrode 108 also consists of a conductive metal such as silver, copper, and their compounds, etc.

[0045] Optionally, the cell 10 further comprises a front surface array 109, which adjoins the substrate front side 1011 in the substrate 101, wherein the doping type of the front surface array 109 is the same as the doping type of the substrate 101 and the front surface array 109 has a higher doping concentration than that of the substrate 101. The thickness of the front surface array 109 is preferably in the range of 0.005 to 5 μm, and the sheet resistance is 10 to 10,000 ohm / sq. In this embodiment, the open circuit voltage and the conversion efficiency of solar cells are further increased by the provision of the front surface array 109, which has the function of reducing the recombination of charge carriers.

[0046] Based on the above description, the present application further provides, in another aspect, a cell assembly comprising a plurality of back contact solar cells according to any one of the embodiments of the present application connected in series and / or parallel, for example the back contact solar cell 10 in Fig. 1.

[0047] In the back-contact solar cell and the cell assembly using the back-contact solar cell provided in the present application, the length dimension and width dimension parameters are optimized for different polarity zones on the back-side structure of the back-contact solar cell, which can take into account the electrical and optical performances of the solar cell and further improve the short-circuit current, open-circuit voltage, and photoelectric conversion efficiency of the solar cell.

[0048] The basic concepts have been described above. It should be understood that the above disclosure of the present application serves only as an example to those skilled in the art, without limiting the present application. Although not explicitly stated, various modifications, improvements, and changes to the present application may be made by those skilled in the art. These modifications, improvements, and changes are indicated in the present application, so they are still intended to be included within the spirit and scope of the exemplary embodiments of the present application.

[0049] This application also uses specific words to describe the embodiments of this application. The terms "one embodiment," "an embodiment," and / or "some embodiments" represent a feature, structure, or feature common to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," and / or "an alternative embodiment" mentioned in different paragraphs of the specification do not necessarily refer to the same embodiment or embodiment. Furthermore, some of the features, structures, or features of one or more embodiments of this application may be combined with each other as appropriate.

[0050] It should also be noted that in the above description of the embodiments of the present application, various features are sometimes grouped into an embodiment, a figure, or its description to simplify the description of the disclosure of the present application and to facilitate understanding of one or more embodiments of the present application. However, this disclosure does not imply that the features of the subject matter of the present application are more than those recited in the claims. In fact, the features of the embodiments are less than all of the features of any of the individual embodiments disclosed above.

[0051] In some embodiments, numbers are used to describe components and features. It should be understood that in some cases, numbers are modified to "approximately," "about," or "substantially" when describing embodiments. Unless otherwise noted, the terms "approximately," "about," or "substantially" mean that these numbers may vary within ±20%. Accordingly, in some embodiments, the valued parameters used in the description and claims are approximate values ​​that may change depending on the requirements of an individual embodiment. In some embodiments, the valued parameters are intended to be used to the prescribed valid digits using a general rounding method.Although in some embodiments of the present application the value range and the parameters for determining their scope are approximate values, in a concrete embodiment the values ​​can be set as precisely as possible.

[0052] Although the present application has been described with reference to the specific embodiments, those skilled in the art should recognize that the above-described embodiments are merely illustrative of the present application, and various equivalent changes or substitutions may be made without departing from the spirit of the present application. Therefore, any changes or variations to the above-described embodiments are within the scope of the claims of the present application, as long as they are made within the spirit of the present application.

Claims

[1] Back contact solar cell, characterized by that it includes: a substrate having a substrate front side and a substrate back side that are opposite each other, the substrate front side facing a main light receiving surface of the cell and the substrate back side facing a non-main light receiving surface of the cell, and the doping type of the substrate being an N-type; a P-type polarity region comprising a first doped semiconductor layer; an N-type polarity region comprising a second doped semiconductor layer, wherein the N-type polarity region and the P-type polarity region are provided alternately on a side facing the substrate backside, wherein the second doped semiconductor layer has a smaller thickness in a normal direction of the cell than the thickness of the first doped semiconductor layer in the normal direction, and wherein the P-type polarity region has a greater width in an extension direction of the cell extending perpendicular to the normal direction than the width of the one adjacent N-type polarity region in the extension direction; and an isolation zone located between any two adjacent N-type polarity zones and P-type polarity zones. [2] Back contact solar cell according to claim 1, characterized by , that the doping type of the first doped semiconductor layer is a P-type doping and doped impurities comprise boron atoms and / or boron-containing compounds; and that the doping type of the second doped semiconductor layer is an N-type doping and doped impurities comprise phosphorus atoms and / or phosphorus-containing compounds. [3] Back contact solar cell according to claim 1, characterized by that the thickness of the first doped semiconductor layer is in the range of 15 to 500 nm and the thickness of the second doped semiconductor layer is in the range of 10 to 400 nm. [4] Back contact solar cell according to claim 1, characterized by that the thickness of the second doped semiconductor layer in the normal direction is 30 to 150 nm thinner than the thickness of the first doped semiconductor layer in the normal direction. [5] Back contact solar cell according to claim 1, characterized bythat the width of the isolation region in the extension direction is less than the width of each P-type polarity region or each N-type polarity region in the extension direction. [6] Back contact solar cell according to one of claims 1 to 4, characterized by that the substrate further comprises, at a location corresponding to the P-type polarity zone, a first doped substrate layer which adjoins the substrate backside in the substrate. [7] Back contact solar cell according to one of claims 1 to 4, characterized by that the P-type polarity zone further comprises a first doped oxide layer having a thickness in the range of 0.5 to 3 nm and adjoining a side of the first doped semiconductor layer facing the substrate backside. [8] Back contact solar cell according to one of claims 1 to 4, characterized bythat the substrate further comprises, at a location corresponding to the N-type polarity zone, a second doped substrate layer which adjoins the substrate backside in the substrate. [9] Back contact solar cell according to one of claims 1 to 4, characterized by that the N-type polarity zone further comprises a second doped oxide layer having a thickness in the range of 0.5 to 3 nm and adjoining a side of the second doped semiconductor layer facing the substrate backside. [10] Back contact solar cell according to one of claims 1 to 4, characterized by that it further comprises a passivated back layer located on an outermost layer of the N-type polarity region, the P-type polarity region and the insulation region facing away from the substrate back. [11] Back contact solar cell according to claim 10, characterized bythat the passivated backing layer comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, or a stacked media layer consisting of two or more thereof. [12] Back contact solar cell according to claim 11, characterized by that it further comprises a first electrode and a second electrode, which are located in the P-type polarity region and the N-type polarity region, respectively, wherein the first electrode and the second electrode each pass through the passivated back layer and are brought into contact with the first doped semiconductor layer and the second doped semiconductor layer. [13] Back contact solar cell according to claim 1, characterized byin that it further comprises a passivated front layer located on a side facing the substrate front side, wherein the passivated front layer comprises a media layer consisting of one of aluminum oxide, silicon nitride, silicon oxynitride, silicon oxide, magnesium fluoride, or a stacked media layer consisting of two or more thereof. [14] Back contact solar cell according to claim 1 or 13, characterized by that the substrate further comprises a front surface field adjacent to the substrate front side, wherein the doping type of the front surface field is the same as the doping type of the substrate and the front surface field has a higher doping concentration than that of the substrate. [15] A cell assembly comprising a plurality of back contact solar cells according to any one of claims 1 to 14 connected in series and / or parallel.

Images