Solar cell and photovoltaic module

Abstract

The present application relates to the technical field of photovoltaics. Provided are a solar cell and a photovoltaic module. The solar cell comprises: a silicon substrate, which comprises a first surface and a second surface opposite each other; an N-type doped layer, which is located on at least a portion of the first surface of the silicon substrate, wherein the sheet resistance of the N-type doped layer ranges from 14 Ohms per square to 40 Ohms per square; and several N-type collector grid lines, which are distributed at intervals and in parallel, and are located on the side of the N-type doped layer that faces away from the silicon substrate, wherein the spacing between adjacent N-type collector grid lines is less than 1.391 mm. In the present application, the sheet resistance of an N-type doped layer ranges from 14 Ohms per square to 40 Ohms per square, and the spacing between adjacent N-type collector grid lines is less than 1.391 mm, such that factors such as parasitic absorption, a recombination current in a metal region, and a lateral resistance can achieve a better balance, resulting in a better performance of the solar cell and a higher photoelectric conversion efficiency.

Description

Solar cell and photovoltaic module

[0001] The present application claims priority to the Chinese patent application No. 202410752794.0, filed on June 11, 2024, and entitled "Solar cell and photovoltaic module", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of photovoltaic technology, in particular to a solar cell and a photovoltaic module. BACKGROUND

[0003] Solar cells can convert solar energy into electrical energy, and they use clean energy, so they have a wide application prospect.

[0004] In a solar cell, various factors need to cooperate with each other to achieve the function of converting solar energy into electrical energy. However, in existing solar cells, the cooperation between various factors is not appropriate enough, resulting in poor performance of the solar cell.

[0005] SUMMARY

[0006] The present application provides a solar cell and a photovoltaic module, aiming to solve the problem that in existing solar cells, the cooperation between different factors is not appropriate enough, resulting in poor performance of the solar cell.

[0007] In a first aspect, the present application provides a solar cell, comprising:

[0008] a silicon substrate, the silicon substrate comprising opposite first and second surfaces;

[0009] an N-type doped layer located on at least a partial region of the first surface of the silicon substrate, the sheet resistance of the N-type doped layer being 14 ohm / square to 40 ohm / square;

[0010] a plurality of N-type collector grid lines distributed in parallel and at intervals, located on a side of the N-type doped layer away from the silicon substrate, the spacing between adjacent N-type collector grid lines being less than 1.391 mm.

[0011] In the present application, the sheet resistance of the N-type doped layer is 14 ohm / square to 40 ohm / square, and the spacing between adjacent N-type collector grid lines is less than 1.391 mm. The sheet resistance of the N-type doped layer and the spacing between adjacent N-type collector grid lines are respectively within the above ranges, so that the parasitic absorption, the recombination current of the metal region, and the lateral resistance and other factors can achieve a better balance, so that the performance of the solar cell is better, and the photoelectric conversion efficiency is higher.

[0012] In some possible embodiments, the sheet resistance of the N-type doped layer is 14 ohm / square to 20 ohm / square, and the pitch between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm; or,

[0013] The sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square, and the pitch between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm.

[0014] In some possible embodiments, the thickness of the N-type doped layer is 100 nm to 140 nm.

[0015] In some possible embodiments, the doping concentration of the N-type doped layer is 3E20 cm -3 to 7E20 cm -3 .

[0016] In some possible embodiments, the solar cell further comprises: a P-type doped layer, the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square;

[0017] A plurality of P-type collector grid lines are spaced and parallel distributed on the side of the P-type doped layer away from the silicon substrate.

[0018] In some possible embodiments, the N-type doped layer comprises: an N-type doped polysilicon layer and / or an N-type doped microcrystalline silicon layer;

[0019] The solar cell further comprises: a first tunneling oxide layer between the N-type doped layer and the silicon substrate;

[0020] The pitch between adjacent P-type collector grid lines is less than or equal to the pitch between adjacent N-type collector grid lines.

[0021] In some possible embodiments, the first surface comprises: first and second conductive regions spaced and distributed;

[0022] The N-type doped layer is on the first conductive region;

[0023] The P-type doped layer is on the second conductive region;

[0024] The solar cell further comprises: a second tunneling oxide layer between the P-type doped layer and the silicon substrate.

[0025] In some possible embodiments, the N-type doped layer is on a first surface of the silicon substrate, and the P-type doped layer is on a second surface of the silicon substrate.

[0026] In some possible embodiments, the P-type doped layer is a P-type polysilicon doped layer and / or a P-type doped microcrystalline silicon layer.

[0027] In a second aspect, the present application provides a solar cell, comprising:

[0028] a silicon substrate; the silicon substrate comprises opposite light-receiving and back surfaces;

[0029] an N-type doped layer on the back surface of the silicon substrate; the N-type doped layer has a thickness of 100-140 nm;

[0030] a plurality of N-type collecting grid lines spaced and parallel to each other on the side of the N-type doped layer away from the silicon substrate; the distance between adjacent N-type collecting grid lines is less than 1.391 mm;

[0031] a P-type doped layer on the light-receiving surface of the silicon substrate;

[0032] a plurality of P-type collecting grid lines spaced and parallel to each other on the side of the P-type doped layer away from the silicon substrate; the distance between adjacent P-type collecting grid lines is less than or equal to the distance between adjacent N-type collecting grid lines.

[0033] In the present application, the N-type doped layer is on the back surface of the silicon substrate, and the N-type doped layer has a thickness of 100-140 nm. The factors such as sheet resistance, parasitic absorption, passivation region recombination current, and metal region recombination current of the N-type doped layer are all favorable, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. At the same time, the distance between adjacent N-type collecting grid lines is less than 1.391 mm, so that the factors such as parasitic absorption, metal region recombination current, and lateral resistance can achieve a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. In addition, the distance between adjacent P-type collecting grid lines is less than or equal to the distance between adjacent N-type collecting grid lines. Specifically, because the P-type doped layer is not easy to obtain a higher doping concentration, the distance between adjacent P-type collecting grid lines can be smaller, which can further improve the efficiency of the solar cell.

[0034] In a third aspect, the present application provides a solar cell, comprising:

[0035] a silicon substrate; the silicon substrate comprises opposite light-receiving and back surfaces;

[0036] the back surface comprises first and second conductive regions spaced apart;

[0037] an N-type doped layer on the first conductive region; the N-type doped layer has a sheet resistance greater than 14 ohms / square and less than or equal to 40 ohms / square;

[0038] a P-type doped layer on the second conductive region; the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square;

[0039] a plurality of N-type collector grid lines distributed in intervals and in parallel on the side of the N-type doped layer facing away from the silicon substrate, the interval between adjacent N-type collector grid lines being less than 1.391 mm.

[0040] In the present application, the N-type doped layer and the P-type doped layer are both on the back surface of the silicon substrate, the sheet resistance of the N-type doped layer is 14 ohm / square to 40 ohm / square, and the interval between adjacent N-type collector grid lines is less than 1.391 mm. The sheet resistance of the N-type doped layer and the interval between adjacent N-type collector grid lines are within the above ranges, respectively, so that the parasitic absorption, the recombination current of the metal region, and the lateral resistance and other factors can achieve a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. The sheet resistance of the P-type doped layer within the range is conducive to improving the efficiency of the solar cell.

[0041] In a fourth aspect of the present application, a photovoltaic module is provided, the photovoltaic module comprising a plurality of cell strings, the cell strings comprising a plurality of solar cells and a plurality of interconnects for connecting the plurality of solar cells in series; wherein the solar cell comprises any one of the preceding solar cells.

[0042] The above-mentioned solar cell and photovoltaic module have the same or similar beneficial effects, and to avoid repetition, they will not be described here.

[0043] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the following specific embodiments of the present application can be implemented according to the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any creative labor.

[0045] Figure 1 shows a partial structure schematic diagram of a solar cell in an embodiment of the present application;

[0046] Figure 2 shows a curve graph of the influence of the sheet resistance of an N-type doped layer and the interval between adjacent N-type collector grid lines on the efficiency of a solar cell in an embodiment of the present application;

[0047] FIG. 3 shows a fitting curve diagram of sheet resistance of an N-type doped layer and spacing between adjacent N-type collector grid lines in an embodiment of the present application;

[0048] FIG. 4 shows a curve diagram of the effect of thickness of an N-type doped layer and spacing between adjacent N-type collector grid lines on efficiency of a solar cell in an embodiment of the present application;

[0049] FIG. 5 shows a curve diagram of the effect of sheet resistance of a P-type doped layer and spacing between adjacent P-type collector grid lines on efficiency of a solar cell in an embodiment of the present application;

[0050] FIGS. 6 to 8 show structure schematic diagrams of several solar cells in embodiments of the present application.

[0051] Explanation of figure number:

[0052] 1-N-type doped layer, 2-N-type collector grid line, 3-silicon substrate, 4-first tunneling oxide layer, 5-P-type doped layer, 6-P-type collector grid line, 7-first passivation anti-reflection layer, 8-second passivation anti-reflection layer, 9-second tunneling oxide layer. Specific embodiments

[0053] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0054] Those skilled in the art should understand that, in the disclosure of the present application, the terms "first", "second", "third", "fourth", "fifth" and the like are only used to distinguish different structures, and do not limit the number, connection relationship and the like of specific structures; in addition, the orientation or position relationship indicated by "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore the above terms cannot be understood as a limitation on the present application.

[0055] The present application provides at least three kinds of solar cells, which will be mainly explained and described from the first aspect, the second aspect and the third aspect. Among them, the solar cell of the first aspect corresponds to the solar cell of the first aspect in the foregoing application content, the solar cell of the second aspect corresponds to the solar cell of the second aspect in the foregoing application content, and the solar cell of the third aspect corresponds to the solar cell of the third aspect in the foregoing application content. Among them, in the solar cell of the first aspect, the N-type doped layer can be located on the entire first surface of the silicon substrate, or the N-type doped layer can be located on part of the first surface of the silicon substrate. In the solar cell of the second aspect, the N-type doped layer can be located on the back light surface of the silicon substrate, and the P-type doped layer is located on the light surface of the silicon substrate, which is a bifacial cell. The specific type of the solar cell of the second aspect is not limited, for example, the solar cell of the second aspect can be a bifacial TOPCON (Tunnel Oxide Passivated Contact) cell. In the solar cell of the third aspect, the N-type doped layer and the P-type doped layer can be located on the back light surface of the silicon substrate, which is a back contact solar cell. The specific type of the solar cell of the third aspect is not limited, for example, the solar cell of the third aspect can be a TBC (TOPCON and IBC combined) cell.

[0056] Before introducing the solar cell of the first aspect, some related contents in the solar cells of the three aspects are introduced generally. In the design of the solar cell, recombination and series resistance are two core factors affecting the efficiency, and the performance needs to be improved through parameter coordination optimization. Therefore, in the solar cell, when the series resistance is the main influencing factor, the low sheet resistance needs to be adjusted to reduce the series resistance and improve the conductivity; in the solar cell, if recombination is the main factor, the doping concentration or depth needs to be considered to be reduced, resulting in high sheet resistance, thereby reducing the recombination of carriers. In the design of the doped layer in the solar cell, for the N-type doped layer and the P-type doped layer, the thickness thereof is usually related to the corresponding sheet resistance, and the general relationship is that: if the thickness of the N-type doped layer and the P-type doped layer is too thin, the sheet resistance may be too high, the current lateral transmission capacity is reduced, and the efficiency of the solar cell is affected; if the thickness of the N-type doped layer and the P-type doped layer is too thick, the light absorption loss may be increased, therefore, the thickness of the N-type doped layer and the P-type doped layer needs to be considered comprehensively in terms of parasitic absorption, doping, sheet resistance and other factors. In the solar cell, for the N-type doped layer and the P-type doped layer, the doping concentration thereof is usually related to the corresponding sheet resistance, and the general relationship is that: the doping concentration of the N-type doped layer and the doping concentration of the P-type doped layer are inversely proportional to the sheet resistance, that is, the higher the doping concentration, the lower the sheet resistance. However, too low doping concentration will result in poor passivation effect and high contact resistance, and too high doping concentration will result in serious parasitic absorption and Auger recombination, therefore, the doping concentration of the N-type doped layer and the doping concentration of the P-type doped layer also needs to be considered comprehensively in terms of sheet resistance, passivation effect, parasitic absorption and other factors. In the solar cell, the current collecting grid is used to collect current or carriers, and the spacing of the current collecting grid has a close relationship with the recombination and shading in the carrier transmission. The present application is to consider the different parameters and related factors comprehensively, and to select the optimized and balanced results as much as possible, so that the cooperation between the factors in the solar cell of the present application is appropriate, and the performance of the solar cell is improved.

[0057] It should be noted that, in order to avoid repetition, in the solar cells of the second aspect and the third aspect, only the differences from the solar cell of the first aspect are described, and the same or related parts of the solar cell of the first aspect can be referred to the foregoing description of the first aspect.

[0058] Now the solar cell of the first aspect is introduced. The solar cell of the first aspect can include: a silicon substrate, the doping type, crystal type and the like of the silicon substrate are not specifically limited, for example, the silicon substrate can be N-type doped monocrystalline silicon, etc. The silicon substrate includes opposite first and second surfaces, one of the first and second surfaces is a light-receiving surface and the other is a back surface, and the surface mainly receiving light is the light-receiving surface during normal operation of the solar cell, and the back surface is opposite to the light-receiving surface.

[0059] The solar cell can further comprise an N-type doped layer, which can form a high-low junction or a PN junction with the aforementioned silicon substrate. The N-type doped layer is located on at least a portion of the first surface of the silicon substrate, which can be the entire first surface or only a portion of the first surface, without specific limitation. The sheet resistance of the N-type doped layer is 14 ohms / square (Ω / □) to 40 ohms / square. The sheet resistance of the N-type doped layer refers to a portion of the N-type doped layer with a length of l, a width of w, and a height of d (i.e., the thickness of the N-type doped layer), where L = l, S = w x d, and thus R sh = p x l / (w x d) = (p / d) x (l / w). Let l = w, then R sh = (p / d), where p is the resistivity of the N-type doped layer, and R sh is the sheet resistance of the N-type doped layer. Here, a square refers to a region in the N-type doped layer with equal length and width, and variable thickness. The length and width of the square have little effect on the sheet resistance, for example, the length and width of the square can both be 1 centimeter or 1 meter, and the corresponding sheet resistance is the same, but the sheet resistance decreases as the thickness of the square increases.

[0060] The solar cell can further comprise a plurality of N-type collector grid lines spaced apart and arranged in parallel on the side of the N-type doped layer away from the silicon substrate, which are used to collect carriers. As shown in FIG. 1, 1 is a schematic of the N-type doped layer, and 2 is a schematic of the N-type collector grid lines. The number of N-type collector grid lines 2 in the solar cell is not limited. In FIG. 1, the silicon substrate is located on the upper side of the N-type doped layer, and the N-type collector grid lines 2 are inserted into the N-type doped layer 1. The spacing between adjacent N-type collector grid lines 2 is less than 1.391 mm (millimeters), which refers to the spacing between two N-type collector grid lines 2 arranged in close proximity. In the present application, the sheet resistance of the N-type doped layer is 14 ohms / square to 40 ohms / square, and the spacing between adjacent N-type collector grid lines is less than 1.391 mm. The sheet resistance of the N-type doped layer and the spacing between adjacent N-type collector grid lines are within the above ranges, respectively, so that the parasitic absorption, the recombination current of the metal region, and the lateral resistance can achieve a better balance, and the performance of the solar cell is better, and the photoelectric conversion efficiency is higher.

[0061] For example, the sheet resistance of the N-type doped layer can be 14 ohm / square, 14.7 ohm / square, 15 ohm / square, 16.8 ohm / square, 17.6 ohm / square, 18.5 ohm / square, 19.3 ohm / square, 20.4 ohm / square, 22 ohm / square, 25 ohm / square, 23.1 ohm / square, 29.5 ohm / square, 27 ohm / square, 30 ohm / square, 32.5 ohm / square, 38 ohm / square, 39.1 ohm / square, 40 ohm / square, and the pitch between adjacent N-type collector grid lines can be 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 1 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm, 0.8 mm.

[0062] More specifically, FIG. 2 is a graph showing the influence of sheet resistance of N-type doped layer, spacing between adjacent N-type collector grid lines on the efficiency of solar cell. For example, referring to FIG. 2, the horizontal axis of FIG. 2 is the sheet resistance of N-type doped layer such as N-type doped polysilicon layer or phosphorus-doped polysilicon layer, the vertical axis of FIG. 2 is the efficiency of solar cell, and the order of the curves from bottom to top of FIG. 2 corresponds to the spacing between adjacent N-type collector grid lines in the order of 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, 1.391 mm, 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm. In FIG. 2, the solar cells with efficiency greater than or equal to 26%, such as 26.0% to 26.5%, are selected as the solar cells with relatively high efficiency, i.e. the part enclosed by the dotted box in FIG. 2, and the part below the dotted box corresponds to the solar cells with efficiency less than 26%. From FIG. 2, it can be seen that among the above-mentioned 15 spacings between adjacent N-type collector grid lines, the spacings between adjacent N-type collector grid lines greater than or equal to 1.391 mm, i.e. 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, 1.391 mm, and / or the sheet resistance of N-type doped layer less than 14 ohm / square or greater than 40 ohm / square correspond to the solar cells with efficiency less than 26%, indicating that the solar cells cannot obtain relatively high efficiency when the spacing between adjacent N-type collector grid lines is greater than or equal to 1.391 mm and / or the sheet resistance of N-type doped layer is less than 14 ohm / square or greater than 40 ohm / square. Therefore, in the present application, the spacing between adjacent N-type collector grid lines is less than 1.391 mm and the sheet resistance of N-type doped layer is 14 ohm / square to 40 ohm / square, which is beneficial to the improvement of the efficiency of solar cell. As shown in FIG. 2, in the present application, the spacing between adjacent N-type collector grid lines is less than 1.391 mm and the sheet resistance of N-type doped layer is 14 ohm / square to 40 ohm / square, so the efficiency of solar cell is greater than or equal to 26%, even reaching 26.5% and above.

[0063] In some possible embodiments, the sheet resistance of the N-type doped layer is 14 ohm / square to 20 ohm / square, and the interval between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm; or, the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square, and the interval between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm. Specifically, referring to FIG. 2, the sheet resistance of the N-type doped layer is 20 ohm / square, and in the part where the efficiency is greater than or equal to 26%, the sheet resistance of the N-type doped layer corresponding to the inflection point of the efficiency is more specific. In the case where the sheet resistance of the N-type doped layer is 14 ohm / square to 20 ohm / square, and the interval between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm, the efficiency of the solar cell is greater than or equal to 26.0%, and the rate of increase in efficiency is the fastest. In the case where the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square, and the interval between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm, the efficiency of the solar cell is greater than or equal to 26.0%, and the rate of decrease in efficiency is the slowest. Therefore, in the present application, the sheet resistance of the N-type doped layer is 14 ohm / square to 20 ohm / square, and the interval between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm; or, the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square, and the interval between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm. Through further combination and optimization of the sheet resistance of the N-type doped layer and the interval between adjacent N-type collector grid lines, the efficiency of the solar cell is further improved. It should be noted that the material of the N-type collector grid line is not specifically limited, for example, the N-type collector grid line can be a silver collector grid line.

[0064] For example, the sheet resistance of the N-type doped layer can be 14 ohm / square, 14.7 ohm / square, 15 ohm / square, 15.3 ohm / square, 16 ohm / square, 16.5 ohm / square, 17 ohm / square, 17.7 ohm / square, 18 ohm / square, 18.5 ohm / square, 19 ohm / square, 19.5 ohm / square, 20 ohm / square, and the spacing between adjacent N-type collector grid lines can be 1.019 mm, 1.05 mm, 1.076 mm, 1.112 mm, 1.141 mm, 1.173 mm, 1.213 mm, 1.25 mm, 1.296 mm. Alternatively, the sheet resistance of the N-type doped layer can be 20.3 ohm / square, 20.7 ohm / square, 21 ohm / square, 21.3 ohm / square, 22 ohm / square, 22.5 ohm / square, 23 ohm / square, 23.5 ohm / square, 24 ohm / square, 24.5 ohm / square, 25 ohm / square, 25.6 ohm / square, 27 ohm / square, 28 ohm / square, 29.6 ohm / square, 30 ohm / square, 31.6 ohm / square, 36.2 ohm / square, 38.56 ohm / square, 40 ohm / square, and the spacing between adjacent N-type collector grid lines can be 0.977 mm, 0.971 mm, 0.967 mm, 0.9 mm, 0.92 mm, 0.913 mm, 0.878 mm, 0.8 mm, 0.839 mm.

[0065] More specifically, in combination with the foregoing FIG. 2, the efficiency of the solar cell is fitted with the relevant data when the efficiency is greater than or equal to 26.0%, such as 26.0% to 26.5%, to obtain a fitting curve between the spacing y between adjacent N-type collector grid lines and the sheet resistance x of the N-type doped layer in a back contact solar cell (BC), as shown in FIG. 3, i.e., y = 0.004x 4 -0.542x 3 +24.53x 2 -492.4x + 4687.3. The correlation R2 of the fitting curve is 0.998, and in the fitting curve or fitting formula, the unit of y is microns (pm), and the unit of x is ohm / square. In FIG. 3, each point includes data on the left and data on the right, and the data on the left in each point is the sheet resistance of the N-type doped layer, and the data on the right is the spacing between adjacent N-type collector grid lines corresponding to the sheet resistance. The combination of the spacing between adjacent N-type collector grid lines and the sheet resistance of the N-type doped layer obtained from the fitting curve can achieve a better balance of parasitic absorption, recombination current of the metal region, and lateral resistance, so that the performance of the solar cell is better, and the photoelectric conversion efficiency is higher.

[0066] In some possible embodiments, the thickness of the N-type doped layer is 100 nm to 140 nm. The thickness of the N-type doped layer is more suitable, which is beneficial to the sheet resistance of the N-type doped layer, parasitic absorption, passivation region recombination current, metal region recombination current and other factors, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. More specifically, referring to FIG. 1, the sidewall of the N-type collector grid line 2 is in contact with the N-type doped layer 1. The larger the height h and the bottom side length a of the N-type collector grid line 2, the larger the sidewall area of the N-type collector grid line 2, and the larger the recombination current of the metal region. Assuming that the recombination rate of the sidewall of the N-type collector grid line 2 is 107cm / s, the recombination current of the metal region and the passivation region recombination current are estimated by area ratio weighted average, and the macroscopic recombination current of the metal region is obtained. In the case that the height h of the N-type collector grid line 2 is fixed, the thickness of the N-type doped layer 1 is changed to t, and the recombination current of the metal region is estimated. FIG. 4 is a curve graph showing the influence of the thickness of the N-type doped layer and the spacing between adjacent N-type collector grid lines on the efficiency of the solar cell. In FIG. 4, the order of each curve from bottom to top corresponds to the spacing between adjacent N-type collector grid lines as follows: 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, 1.391 mm, 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm, a total of 15 spacings. In FIG. 4, each point includes data on the left and data on the right. The data on the left in the point is the thickness of the N-type doped layer, and the data on the right is the efficiency of the solar cell corresponding to the thickness. According to FIG. 4, it can be concluded that when the thickness of the N-type doped layer is 100 nm to 140 nm, especially about 120 nm, the efficiency of the solar cell basically reaches the maximum for the above-mentioned 15 spacings between adjacent N-type collector grid lines. At the same time, when the thickness of the N-type doped layer is less than 100 nm, the efficiency of the solar cell increases with the increase of the thickness of the N-type doped layer, and when the thickness of the N-type doped layer is greater than 140 nm, the efficiency of the solar cell remains stable or tends to decrease with the increase of the thickness of the N-type doped layer. Moreover, the recombination current of the metal region estimated by the foregoing method is smaller when the thickness of the N-type doped layer is 100 nm to 140 nm. Therefore, in this application, the thickness of the N-type doped layer is 100 nm to 140 nm, which is beneficial to the sheet resistance of the N-type doped layer, parasitic absorption, passivation region recombination current, metal region recombination current and other factors, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. For example, if the thickness of the N-type doped layer is 120 nm, the formula The sheet resistance R of the N-type doped layer is roughly estimated as sh The sheet resistance R of the N-type doped layer is calculated as shapproximately 29.5 ohm / square, within the range of 14 ohm / square to 40 ohm / square as mentioned above. In the above formula, q is a basic charge or elementary charge, q = 1.6021766208 x 10 -19 C, μ is a migration rate (drift rate of a carrier under a unit electric field intensity) approximately 35.27 cm 2 / V·s, n is a doping concentration of the N-type doped layer, approximately 5 x 10 20 cm -3 , and t is a thickness of the N-type doped layer, i.e. 120 nm.

[0067] For example, the thickness of the N-type doped layer can be 100 nm, 103.2 nm, 105 nm, 109 nm, 110 nm, 115 nm, 118.3 nm, 120 nm, 125 nm, 128 nm, 130 nm, 132.3 nm, 135 nm, 137.9 nm, 140 nm.

[0068] In some possible embodiments, the doping concentration of the N-type doped layer is 3E20 cm -3 to 7E20 cm -3 Specifically, the doping concentration of the N-type doped layer is an important factor affecting the sheet resistance of the N-type doped layer, and in the present application, the doping concentration of the N-type doped layer is limited within a more appropriate range, so that the sheet resistance of the N-type doped layer can be within the aforementioned required range.

[0069] For example, the doping concentration of the N-type doped layer can be 3E20 cm -3 , 3.2E20 cm -3 , 3.5E20 cm -3 , 4E20 cm -3 , 4.3E20 cm -3 , 4.7E20 cm -3 , 4.21E20 cm -3 , 5E20 cm -3 , 5.2E20 cm -3 , 5.5E20 cm -3 , 6E20 cm -3 , 6.3E20 cm -3 , 7E20 cm -3 .

[0070] In some possible embodiments, the solar cell further comprises: a P-type doped layer, the P-type doped layer forms a PN junction or a high-low junction with the silicon substrate, and the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square. The sheet resistance of the P-type doped layer refers to: for a portion of the P-type doped layer with a length of l, a width of w, and a height of d (i.e. the thickness of the P-type doped layer), at this time, the L = l, the S = w x d, and thus the Rsh = p x l / (w x d) = (p / d) x (l / w). Let l = w then R sh = (p / d), where p is the resistivity of the P-type doped layer, and R sh = (p / d), where p is the resistivity of the P-type doped layer, and R

[0071] More specifically, refer to FIG. 5 below, which is a graph showing the effect of the sheet resistance of the P-type doped layer, such as a boron-doped polysilicon layer, and the spacing between adjacent P-type collector grid lines on the efficiency of a solar cell. The horizontal axis of FIG. 5 is the sheet resistance of the P-type doped layer, such as a P-type doped polysilicon layer or a boron-doped polysilicon layer, and the vertical axis of FIG. 5 is the efficiency of the solar cell. In FIG. 5, the order of the curves from bottom to top corresponds to the spacing between adjacent P-type collector grid lines being 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, 1.391 mm, 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm, for a total of 15 spacings. In FIG. 5, the portion enclosed by the dashed box corresponds to the efficiency of the solar cell being greater than or equal to 25.99%, and the portion outside the box corresponds to the efficiency of the solar cell being less than 25.99%. As can be seen from FIG. 5, when the sheet resistance of the P-type doped layer is between 20 ohms / square and 166 ohms / square, the solar cell has good performance and a high efficiency of 25.99% or more. In FIG. 5, the data of the two points includes the data on the left and the data on the right, and the data on the left is the sheet resistance of the P-type doped layer, and the data on the right is the efficiency of the solar cell corresponding to the sheet resistance. In this application, by matching and limiting the sheet resistance of the N-type doped layer and the sheet resistance of the P-type doped layer, the solar cell can be appropriately selected to have a relatively large grid line spacing, thereby reducing the grid line consumption.

[0072] For example, the sheet resistance of the P-type doped layer can be 20 ohms / square, 20.5 ohms / square, 36 ohms / square, 40 ohms / square, 50 ohms / square, 60 ohms / square, 70 ohms / square, 80 ohms / square, 90 ohms / square, 93 ohms / square, 100 ohms / square, 120 ohms / square, 130 ohms / square, 140 ohms / square, 150 ohms / square, 160 ohms / square, or 166 ohms / square.

[0073] In some possible embodiments, the N-type doped layer includes an N-type doped polysilicon layer and / or an N-type doped microcrystalline silicon layer, and the solar cell further includes a first tunneling oxide layer between the N-type doped layer and the silicon substrate, and the first tunneling oxide layer and the aforementioned N-type doped layer can form a passivated contact structure, further improving the efficiency of the solar cell. The spacing between adjacent P-type collector grid lines is less than or equal to the spacing between adjacent N-type collector grid lines. Specifically, because the P-type doped layer is not easy to obtain a higher doping concentration, the spacing between adjacent P-type collector grid lines can be smaller, further improving the efficiency of the solar cell. In the case where the spacing between adjacent P-type collector grid lines is less than the spacing between adjacent N-type collector grid lines, the difference between the two is not specifically limited. It should be noted that the material of the P-type collector grid line is not specifically limited, and whether the material of the P-type collector grid line is the same as the material of the N-type collector grid line is also not specifically limited. For example, the P-type collector grid line can be a silver collector grid line, etc.

[0074] In some possible embodiments, the first surface of the aforementioned silicon substrate includes spaced first conductive regions and second conductive regions, the spacing between the first conductive regions and the second conductive regions is used to avoid electric leakage, and the relative sizes of the first conductive regions and the second conductive regions are not specifically limited. The N-type doped layer is located on the first conductive regions, and the P-type doped layer is located on the second conductive regions. The solar cell can further include a second tunneling oxide layer between the P-type doped layer and the silicon substrate, and the second tunneling oxide layer and the first tunneling oxide layer can be formed in the same process, or the second tunneling oxide layer and the first tunneling oxide layer can be formed in different processes, which is not specifically limited. In the case where the second tunneling oxide layer and the first tunneling oxide layer are formed in different processes, whether the first tunneling oxide layer is formed first or the second tunneling oxide layer is formed first is not specifically limited. For example, the first tunneling oxide layer can be formed first, and then the second tunneling oxide layer can be formed. The first surface herein can be the back surface of the silicon substrate, and the solar cell is a back contact solar cell. In the solar cell, the light-receiving surface of the silicon substrate is not blocked by electrodes, and has a higher efficiency.

[0075] In some possible embodiments, the N-type doped layer can be located on the first surface of the silicon substrate, or in other words, the N-type doped layer covers the entire first surface of the silicon substrate, the P-type doped layer is located on the second surface of the silicon substrate, or in other words, the P-type doped layer covers the entire second surface of the silicon substrate, and the solar cell is a bifacial solar cell. The type of the solar cell is flexible, and among the first surface and the second surface, one is a light-receiving surface and the other is a back surface. For example, the silicon substrate can be an N-type doped monocrystalline silicon, the N-type doped layer can be an N-type doped polysilicon layer, the N-type doped polysilicon layer can be located on the back surface of the silicon substrate, the P-type doped layer can be a P-type doped polysilicon layer, the P-type doped polysilicon layer can be located on the light-receiving surface of the silicon substrate, and a first tunneling oxide layer can be further arranged between the N-type doped layer and the silicon substrate. The solar cell can further include a film layer such as an anti-reflection layer, and other film layers included therein are not specifically limited.

[0076] In some possible embodiments, the P-type doped layer can be a P-type polysilicon doped layer and / or a P-type doped microcrystalline silicon layer, and a P-type diffusion layer. The P-type doped layer is flexible.

[0077] The solar cell of the first aspect of the present application is further explained below in combination with specific embodiments.

[0078] The solar cell is a back contact solar cell. The silicon substrate is an N-type doped monocrystalline silicon, the first surface of the silicon substrate is a back surface, the first surface includes first conductive regions and second conductive regions that are spaced apart, and the spacing between the first conductive regions and the second conductive regions is used to avoid electric leakage. The N-type doped layer is an N-type doped polysilicon layer, and the P-type doped layer is a P-type doped polysilicon layer. The N-type doped polysilicon layer is located on the first conductive regions, and the P-type doped polysilicon layer is located on the second conductive regions. The doping elements in the N-type doped polysilicon layer include phosphorus, and the doping elements in the P-type doped layer include boron. A second tunneling oxide layer is further arranged between the P-type doped polysilicon layer and the silicon substrate, a first tunneling oxide layer is further arranged between the N-type doped polysilicon layer and the silicon substrate, the sheet resistance of the N-type doped polysilicon layer is 24 ohms / square, the sheet resistance of the P-type doped polysilicon layer is 59 ohms / square, the spacing between adjacent N-type current collection grid lines is 0.9 mm, and the spacing between adjacent P-type current collection grid lines is also 0.9 mm. The various cell performance parameters of the back contact solar cell are measured, and the measurement results and the above parameters of the back contact are shown in the following table.

[0079] Table of parameters of the back contact solar cell

[0080] In the above table, Eta is the efficiency of the back contact solar cell, Voc is the open circuit voltage of the back contact solar cell, Jsc is the short circuit current density of the back contact solar cell, and FF is the fill factor of the back contact solar cell. The efficiency of the back contact solar cell has reached as high as 26.5%, mainly because in the back contact solar cell, the mutual cooperation of the sheet resistance of the N-type doped polysilicon layer, the sheet resistance of the P-type doped polysilicon layer, the spacing between adjacent N-type collector grid lines, and the spacing between adjacent P-type collector grid lines has made the factors such as parasitic absorption, recombination current of the metal region, and lateral resistance in the back contact solar cell reach a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher.

[0081] Before introducing the solar cell of the second aspect and the solar cell of the third aspect, two key features common in the structure of the solar cell of the second aspect and the solar cell of the third aspect are first summarized. First, the sheet resistance of the P-type doped layer 5 is greater than the sheet resistance of the N-type doped layer 1; second, the doping concentration of the P-type doped layer 5 is less than the doping concentration of the N-type doped layer 1; such a setting can optimize the process cycle, improve the process efficiency, etc.; in addition, in the case of an N-type silicon substrate, the P-type doped layer 5 forms a PN junction or an emission junction with the N-type silicon substrate, which is used to separate electrons and holes, and the N-type doped layer 1 forms a high-low junction with the N-type silicon substrate, which accelerates the collection of electrons. The sheet resistance of the P-type doped layer 5 being greater than the sheet resistance of the N-type doped layer 1 can reduce the contact recombination of the PN junction or the emission junction, and the doping concentration of the P-type doped layer 5 being less than the doping concentration of the N-type doped layer 1 reduces the parasitic absorption and Auger recombination at the emitter, which is conducive to the generation of carriers; for the high-low junction, the sheet resistance of the N-type doped layer 1 is smaller, which can increase the transmission and collection of majority carriers, and the doping concentration of the N-type doped layer 1 is higher, so that the contact resistance between the doped layer collecting majority carriers and the electrode is smaller; therefore, the present application optimizes and balances the PN junction and the high-low junction, further improving the conversion efficiency of the solar cell.

[0082] Referring to FIGS. 6 and 7, the solar cell of the second aspect will be introduced below. The relevant parts of the solar cell of the second aspect are all referred to the relevant description of the solar cell of the first aspect described above, and only the differences from the solar cell of the first aspect will be introduced to avoid repetition. The solar cell of the second aspect can be a bifacial TOPCON cell.

[0083] The solar cell of the second aspect includes a silicon substrate 3, an N-type doped layer 1, N-type collector grid lines 2, a P-type doped layer 5, and P-type collector grid lines 6. The doping type, crystal type, etc. of the silicon substrate are not specifically limited, for example, the silicon substrate can be an N-type doped single crystal silicon, etc. In FIGS. 6 to 7, the lower surface of the silicon substrate 3 is the back light surface, and the upper surface is the light surface.

[0084] The N-type doped layer 1 is located on the back surface of the silicon substrate 3, and the N-type doped layer 1 and the aforementioned silicon substrate 3 can form a high-low junction or a PN junction, which is not specifically limited. Referring to FIG. 6, the N-type doped layer 1 can be located on the entire back surface of the silicon substrate 3, and in some embodiments, referring to FIG. 7, the N-type doped layer 1 can be located only on a partial area of the back surface of the silicon substrate 3, for example, the N-type doped layer 1 can be located only on a partial area of the back surface of the silicon substrate 3 in the form of a finger structure. The thickness of the N-type doped layer 1 is 100 nm to 140 nm, which is relatively suitable, and is beneficial to several factors such as sheet resistance, parasitic absorption, passivation region recombination current, metal region recombination current, and the like of the N-type doped layer 1, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. More specifically, referring to FIG. 1, the sidewall of the N-type collector grid line 2 is in contact with the N-type doped layer 1, the greater the height h and the bottom side length a of the N-type collector grid line 2, the greater the sidewall area of the N-type collector grid line 2, and the greater the recombination current of the metal region. Assuming that the recombination rate of the sidewall of the N-type collector grid line 2 is 107cm / s, the recombination current of the metal region and the passivation region recombination current are estimated by area ratio weighted average to obtain the macroscopic recombination current of the metal region. In the case that the height h of the N-type collector grid line 2 is fixed, the thickness of the N-type doped layer 1 is changed to t, and the recombination current of the metal region is estimated. For specific reasons, refer to the foregoing FIG. 4 and the related description of FIG. 4, which will not be repeated here.

[0085] The solar cell can further include a plurality of N-type collector grid lines distributed at intervals and in parallel on the side of the N-type doped layer 1 away from the silicon substrate 3, and the N-type collector grid lines are used to collect carriers. For the sake of brevity, reference can be made to the foregoing related description, which will not be repeated here. The distance between adjacent N-type collector grid lines 2 is less than 1.391 mm, and the distance between adjacent N-type collector grid lines 2 refers to the distance between two N-type collector grid lines 2 arranged in close proximity. The distance between adjacent N-type collector grid lines is less than 1.391 mm, and the distance between adjacent N-type collector grid lines is within the above range, so that the parasitic absorption, the recombination current of the metal region and the lateral resistance and other factors can achieve a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. For specific reasons and related description, refer to the foregoing FIG. 2 and the related description, which will not be repeated here.

[0086] For example, the distance between adjacent N-type collector grid lines can be 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 1 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm, 0.8 mm, 0.65 mm.

[0087] The P-type doped layer 5 is located on the light-receiving side of the silicon substrate 3, i.e. the N-type doped layer 1 of the solar cell of the second aspect is located on the back side of the silicon substrate 3, and the P-type doped layer 5 is located on the light-receiving side of the silicon substrate 3. The solar cell is a bifacial solar cell, and other structures of the solar cell are not limited. The P-type doped layer 5 forms a PN junction or a high-low junction with the silicon substrate 3. The P-type doped layer 5 can cover the entire light-receiving side of the silicon substrate 3 or part of the light-receiving side, and this is not limited. For example, the silicon substrate 3 can be an N-type doped single crystal silicon, the N-type doped layer 1 is an N-type doped polysilicon layer, the N-type doped polysilicon layer is located on the back side of the silicon substrate 3, the P-type doped layer 5 is a boron diffusion layer or a P-type doped polysilicon layer, and the P-type doped layer is located on the light-receiving side of the silicon substrate 3. The first tunneling oxide layer 4 is further arranged between the N-type doped layer 1 and the silicon substrate 3. The solar cell can further include a first passivation anti-reflection layer 7 located on the side of the P-type doped layer 5 away from the silicon substrate, and a second passivation anti-reflection layer 8 located on the side of the N-type doped layer 1 away from the silicon substrate, and other film layers included are not specifically limited. The specific materials of the first passivation anti-reflection layer 7 and the second passivation anti-reflection layer 8 are not limited, and whether the materials of the two are the same is also not specifically limited. For example, the first passivation anti-reflection layer 7 and the second passivation anti-reflection layer 8 can both be a mixture of aluminum oxide and silicon nitride, or one of the two can be a silicon nitride layer.

[0088] The solar cell can further include a plurality of P-type collecting grid lines 6 distributed at intervals and in parallel on the side of the P-type doped layer 5 away from the silicon substrate 3, the P-type collecting grid lines 6 being used to collect carriers. The spacing between adjacent P-type collecting grid lines 6 is less than or equal to the spacing between adjacent N-type collecting grid lines. Specifically, in the solar cell, recombination and series resistance are two relatively major influencing factors, and for a bifacial TOPCON cell, recombination has a more serious impact on the cell, mainly because: first, the P-type doped layer 5 of the TOPCON cell is located on the light side of the silicon substrate 3 and is formed by boron diffusion of the silicon substrate, and the recombination caused by the diffusion of the P-type doped layer 5 into the silicon substrate is more serious than the recombination caused by the inward diffusion of the N-type doped layer 1 into the silicon substrate through the first tunneling oxide layer 4, and at the same time, the higher the doping concentration of the P-type doped layer 5, the deeper the doping, the greater the diffusion of the P-type doped layer 5 into the silicon substrate, and the more serious the recombination. Therefore, in order to reduce the degree of diffusion of the P-type doped layer 5 into the silicon substrate, or in other words, to reduce the degree of recombination, in the present application, the doping concentration and junction depth of the P-type doped layer 5 are appropriately controlled so that the doping concentration of the P-type doped layer 5 is lower and the junction depth is shallower. This design will cause the sheet resistance of the P-type doped layer 5 to be larger, and the lateral transport capacity of the carriers will be reduced. In order to improve the lateral transport capacity of the carriers, in the present application, the spacing between adjacent P-type collecting grid lines 6 is appropriately reduced, and the distance of lateral transport of the carriers is shortened, effectively offsetting the adverse effects of the larger sheet resistance of the P-type doped layer 5, and the efficiency of the solar cell can be further improved. Second, because the P-type doped layer 5 is made by a boron diffusion process, the boron diffusion process is more difficult than the phosphorus diffusion process of the N-type doped layer 1, and if a higher doping concentration is desired, a long-process high-temperature process is required, which has an adverse effect on the performance of the cell. Therefore, by making the doping concentration of the P-type doped layer 5 lower, the negative effects of the long-process high-temperature process are reduced. Reducing the doping concentration of the P-type doped layer 5 will cause its sheet resistance to be slightly larger, and based on the foregoing discussion, the spacing between adjacent P-type collecting grid lines 6 can be smaller, which can further improve the efficiency of the solar cell. In the case where the spacing between adjacent P-type collecting grid lines 6 is less than the spacing between adjacent N-type collecting grid lines, the difference between the two is not specifically limited. It should be noted that the material of the P-type collecting grid lines 6 is not specifically limited, and whether the material of the P-type collecting grid lines 6 is the same as that of the N-type collecting grid lines is also not specifically limited, for example, the P-type collecting grid lines 6 can be silver collecting grid lines, etc.

[0089] It should be noted that, in the case that the interval between the adjacent P-type collector grid lines 6 is less than the interval between the adjacent N-type collector grid lines, the line width of the P-type collector grid line 6 can be appropriately reduced so that the light shielding caused by the P-type collector grid line 6 is substantially equal to the case that the interval between the adjacent P-type collector grid lines 6 is equal to the interval between the adjacent N-type collector grid lines. For example, in the present application, in the case that the interval between the adjacent P-type collector grid lines 6 is equal to the interval between the adjacent N-type collector grid lines, the line width of the P-type collector grid line 6 can be 30 μm to 35 μm. For another example, in the present application, in the case that the interval between the adjacent P-type collector grid lines 6 is less than the interval between the adjacent N-type collector grid lines, the line width of the P-type collector grid line 6 can be 25 μm to 30 μm. In some embodiments, it can be concluded from FIG. 5 that, in the case that the interval between the adjacent P-type collector grid lines 6 is less than 1.391 mm, the performance of the solar cell is relatively good, and the efficiency of the solar cell is relatively high, reaching 26% or more. For example, the interval between the adjacent P-type collector grid lines 6 can be 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.99 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm.

[0090] In some embodiments, the P-type doped layer 5 is a P-type polysilicon doped layer and / or a P-type doped microcrystalline silicon layer, a P-type diffusion layer, and the P-type doped layer 5 is flexible and diverse.

[0091] In some embodiments, the N-type doped layer 1 comprises an N-type doped polysilicon layer and / or an N-type doped microcrystalline silicon layer.

[0092] In some embodiments, the interval between the adjacent N-type collector grid lines is 0.839 mm to 0.977 mm.

[0093] In some embodiments, the interval between the adjacent N-type collector grid lines is 0.839 mm to 0.977 mm, specifically, the interval between the adjacent N-type collector grid lines is 1.019 mm to 1.296 mm, the efficiency of the solar cell is greater than or equal to 26.0%, and the rate of increase in the efficiency is the fastest, the efficiency of the solar cell is greater than or equal to 26.0% in the case that the interval between the adjacent N-type collector grid lines is 0.839 mm to 0.977 mm, and the rate of decrease in the efficiency is the slowest, therefore, in the present application, the interval between the adjacent N-type collector grid lines is 0.839 mm to 0.977 mm, the efficiency of the solar cell is further improved by further optimization of the interval between the adjacent N-type collector grid lines. It should be noted that the material of the N-type collector grid line is not specifically limited, for example, the N-type collector grid line can be a silver collector grid line.

[0094] For example, the spacing between adjacent N-type collector grid lines can be 0.977 mm, 0.971 mm, 0.967 mm, 0.9 mm, 0.92 mm, 0.913 mm, 0.878 mm, 0.8 mm, 0.839 mm.

[0095] In some embodiments, the doping concentration of the N-type doped layer 1 is 3E20 cm -3 to 7E20 cm -3 Specifically, the doping concentration of the N-type doped layer 1 is an important factor affecting the sheet resistance of the N-type doped layer 1. In the present application, the doping concentration of the N-type doped layer 1 is limited within the above suitable range, so that the sheet resistance of the N-type doped layer 1 is within a suitable range, and the factors such as parasitic absorption, recombination current of the metal region and lateral resistance can achieve a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher.

[0096] For example, the doping concentration of the N-type doped layer 1 can be 3E20 cm -3 , 3.2E20 cm -3 , 3.5E20 cm -3 , 4E20 cm -3 , 4.3E20 cm -3 , 4.7E20 cm -3 , 4.21E20 cm -3 , 5E20 cm -3 , 5.2E20 cm -3 , 5.5E20 cm -3 , 6E20 cm -3 , 6.3E20 cm -3 , 7E20 cm -3 .

[0097] In some embodiments, the sheet resistance of the N-type doped layer 1 is greater than 20 ohms / square and less than or equal to 40 ohms / square. The definition of the sheet resistance of the N-type doped layer 1 is referred to the foregoing description, and will not be repeated here. For specific reasons, refer to the foregoing FIG. 2, and will not be repeated here.

[0098] For example, the sheet resistance of the N-type doped layer 1 can be 20.3 ohm / square, 20.7 ohm / square, 21 ohm / square, 21.3 ohm / square, 22 ohm / square, 22.5 ohm / square, 23 ohm / square, 23.5 ohm / square, 24 ohm / square, 24.5 ohm / square, 25 ohm / square, 25.6 ohm / square, 27 ohm / square, 28 ohm / square, 29.6 ohm / square, 30 ohm / square, 31.6 ohm / square, 36.2 ohm / square, 38.56 ohm / square, 40 ohm / square, and the spacing between adjacent N-type collector grid lines can be 0.977 mm, 0.971 mm, 0.967 mm, 0.9 mm, 0.92 mm, 0.913 mm, 0.878 mm, 0.8 mm, 0.839 mm.

[0099] In some embodiments, the sheet resistance of the N-type doped layer 1 is 14 ohm / square to 20 ohm / square, and the spacing between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm. For specific reasons, refer to the foregoing FIG. 2, and to avoid repetition, details are not described here.

[0100] For example, the sheet resistance of the N-type doped layer 1 can be 14 ohm / square, 14.7 ohm / square, 15 ohm / square, 15.3 ohm / square, 16 ohm / square, 16.5 ohm / square, 17 ohm / square, 17.7 ohm / square, 18 ohm / square, 18.5 ohm / square, 19 ohm / square, 19.5 ohm / square, 20 ohm / square, and the spacing between adjacent N-type collector grid lines can be 1.019 mm, 1.05 mm, 1.076 mm, 1.112 mm, 1.141 mm, 1.173 mm, 1.213 mm, 1.25 mm, 1.296 mm.

[0101] For example, the sheet resistance of the N-type doped layer 1 can be 14 ohm / square, 14.7 ohm / square, 15 ohm / square, 16.8 ohm / square, 17.6 ohm / square, 18.5 ohm / square, 19.3 ohm / square, 20.4 ohm / square, 22 ohm / square, 25 ohm / square, 23.1 ohm / square, 29.5 ohm / square, 27 ohm / square, 30 ohm / square, 32.5 ohm / square, 38 ohm / square, 39.1 ohm / square, 40 ohm / square.

[0102] In some embodiments, the sheet resistance of the P-type doped layer 5 is in the range of 20 ohm / square to 166 ohm / square. The sheet resistance of the P-type doped layer 5 in this range is beneficial to improve the efficiency of the solar cell, for example, to make the efficiency of the solar cell greater than or equal to 25.99%. For details, please refer to the foregoing description of FIG. 5 and the corresponding description, which will not be repeated here.

[0103] For example, the sheet resistance of the P-type doped layer 5 can be 20 ohm / square, 20.5 ohm / square, 36 ohm / square, 40 ohm / square, 50 ohm / square, 60 ohm / square, 70 ohm / square, 80 ohm / square, 90 ohm / square, 93 ohm / square, 100 ohm / square, 120 ohm / square, 130 ohm / square, 140 ohm / square, 150 ohm / square, 160 ohm / square, 165 ohm / square, 166 ohm / square.

[0104] In some embodiments, the solar cell further comprises a first tunneling oxide layer 4 between the N-type doped layer 1 and the silicon substrate 3. The first tunneling oxide layer 4 and the N-type doped layer 1 can form a passivated contact structure, further improving the efficiency of the solar cell. In FIG. 7, the first tunneling oxide layer 4 and the N-type doped layer 1 are both only provided on a part of the back surface of the silicon substrate, and an electrode is provided thereon. In a bifacial TOPCON cell, it is necessary to reduce the Auger recombination and parasitic absorption in the non-electrode contact area, and to increase the doping amount in the electrode contact area to reduce the contact resistance and metal semiconductor recombination. Therefore, the solar cell of FIG. 7 only provides the electrode contact area with a local passivated contact structure. Compared with the solar cell shown in FIG. 6, the non-electrode contact area of the solar cell of FIG. 7 is only provided with the second passivation and anti-reflection layer 8, thereby reducing the parasitic absorption caused by the N-type doped layer 1 by reducing the coverage area of the doped layer; the electrode contact area is provided with a local passivated contact structure, which ensures the contact effect of the electrode and improves the conversion efficiency of the solar cell. Further, the non-electrode contact area in FIG. 7 can be provided with a textured structure, thereby increasing light absorption and improving the bifacial rate.

[0105] In some embodiments, when the P-type doped layer 5 is a P-type doped polysilicon layer, the solar cell can further comprise a second tunneling oxide layer between the P-type doped layer 5 and the silicon substrate 3. The second tunneling oxide layer and the first tunneling oxide layer 4 can be formed in the same process, or the second tunneling oxide layer and the first tunneling oxide layer 4 can be formed in different processes, which is not specifically limited. In the case that the second tunneling oxide layer and the first tunneling oxide layer are formed in different processes, whether the first tunneling oxide layer 4 is formed first or the second tunneling oxide layer is formed first is not specifically limited. For example, the first tunneling oxide layer can be formed first, and then the second tunneling oxide layer is formed subsequently.

[0106] The solar cell of the second aspect will be further explained in combination with specific embodiments as follows.

[0107] Referring to the bifacial TOPCON cell shown in FIGS. 6-7, the N-type doped layer 1 is an N-type doped polysilicon layer, and the thickness of the N-type doped layer 1 is about 135 nm. The spacing between adjacent N-type collector grid lines 2 is about 0.839-0.977 mm, for example, about 0.92 mm. The spacing between adjacent P-type collector grid lines 6 is also in the range of 0.839-0.977 mm, but is less than the spacing between adjacent N-type collector grid lines 2, for example, the spacing between adjacent P-type collector grid lines 6 can be about 0.89 mm. The sheet resistance of the N-type doped layer 1 is about 14-45 ohms / square, further about 40-45 ohms / square. For example, it can be about 42 ohms / square. The sheet resistance of the P-type doped layer is about 200-500 ohms / square, further about 200-300 ohms / square, for example, it can be about 220 ohms / square. The doping concentration of the N-type doped layer is about 2E20 cm -3 -5E21 cm -3 . The doping concentration of the heavily doped portion of the P-type doped layer is about 3E18 cm -3 -5E19 cm -3 . The doping concentration of the shallowly doped portion of the P-type doped layer is about 2E18 cm -3 -3E18 cm -3The silicon substrate is an N-type silicon substrate. When the P-type doped layer is a P-type diffusion layer obtained by boron diffusion on the silicon substrate, the P-type diffusion layer and the N-type silicon substrate form a PN junction, and the junction depth of the PN junction is about 0.5-2 μm. It should be noted that the back surface of the silicon substrate also has an inner extension layer, and the depth of the inner extension layer is about 20-100 nm. For the back surface of the silicon substrate, the first tunneling oxide layer 4 can block the inner extension of the N-type doped layer 1 into the silicon substrate, and the slight inner extension of the N-type doped layer 1 into the silicon substrate can also play a role in field passivation, improving the tunneling effect, and reducing the series resistance. In this application, the inner extension refers to the phenomenon that the doped elements diffuse into the silicon substrate during the diffusion process. In addition, the doping concentration distribution of the N-type doped layer 1 is more uniform than the doping concentration distribution of the P-type diffusion layer.

[0108] It should be noted that, compared with the prior art, in order to improve the current collection efficiency and match the square resistance of the P-type doped layer and the N-type doped layer, the spacing between the N-type collector grid lines and the P-type collector grid lines can be further reduced, the recombination in the carrier transport can be reduced, and the number of grid lines can be increased. Therefore, the line width of the N-type collector grid lines and the P-type collector grid lines is appropriately reduced, for example, the line width of the N-type collector grid lines and the P-type collector grid lines can be 20-30 μm. Even if the number of grid lines increases, the light shielding area caused by the N-type collector grid lines and the P-type collector grid lines is basically the same as before. For example, in this application, the line width of the N-type collector grid lines and the P-type collector grid lines can be 25 μm, the spacing between adjacent N-type collector grid lines 2 is 0.92 mm, and the spacing between adjacent P-type collector grid lines 6 is 0.89 mm.

[0109] In some embodiments, there is also a ratio relationship between the grid line width and the spacing between adjacent grid lines of the same polarity. When the ratio of the spacing between adjacent grid lines of the same polarity to the grid line width is 20-49, further 20-37, the setting of the grid lines can not only meet the transmission requirements, but also ensure that the light shielding area is as small as possible, thereby improving the current collection efficiency. For example, in this application, the grid line width is 28 μm, the distance between adjacent N-type grid lines is 0.92 mm, and the ratio of the distance between adjacent N-type grid lines to the grid line width is 32.85, thereby improving the collection efficiency of the battery. For another example, the ratio of the spacing between adjacent grid lines of the same polarity to the grid line width can be 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, or 37.

[0110] The following describes the solar cell of the third aspect. The relevant parts of the solar cell of the third aspect are described with reference to the relevant descriptions of the solar cells of the first and second aspects. To avoid repetition, only the differences between the solar cells of the first and second aspects are described.

[0111] Referring to FIG. 8, the solar cell of the third aspect comprises a silicon substrate 3, an N-type doped layer 1, a P-type doped layer 5 and N-type collecting grid lines. The silicon substrate 3 comprises opposite light-receiving and back sides; the back side comprises first and second conductive regions distributed at intervals, the intervals between the first and second conductive regions being used to avoid electric leakage, and the relative sizes of the first and second conductive regions are not limited. The N-type doped layer 1 is located on the first conductive region; the P-type doped layer 5 is located on the second conductive region, and the solar cell is a back contact solar cell, in which the light-receiving side of the silicon substrate 3 is not blocked by electrodes and has higher efficiency. The sheet resistance of the P-type doped layer 5 is 20-166 ohms / square, which is conducive to improving the efficiency of the solar cell; the sheet resistance of the N-type doped layer 1 is greater than 14 ohms / square and less than or equal to 40 ohms / square; a plurality of N-type collecting grid lines distributed at intervals and in parallel are located on the side of the N-type doped layer 1 away from the silicon substrate 3; the distance between adjacent N-type collecting grid lines is less than 1.391 mm; the sheet resistance of the N-type doped layer 1 and the distance between adjacent N-type collecting grid lines are within the above ranges, respectively, so that the factors such as parasitic absorption, recombination current of the metal region and lateral resistance can achieve a better balance, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher.

[0112] For example, the sheet resistance of the N-type doped layer 1 can be 14, 14.7, 15, 16.8, 17.6, 18.5, 19.3, 20.4, 22, 25, 23.1, 29.5, 27, 30, 32.5, 38, 39.1, 40 ohms / square, and the distance between adjacent N-type collecting grid lines can be 1.296, 1.213, 1.141, 1.076, 1.019, 1, 0.977, 0.967, 0.92, 0.878, 0.839, 0.8 mm.

[0113] More specifically, FIG. 2 is a graph showing the effect of sheet resistance of the N-type doped layer 1 and the spacing between adjacent N-type collector grid lines on the efficiency of the solar cell. For example, referring to FIG. 2, the horizontal axis of FIG. 2 represents the sheet resistance of the N-type doped layer 1, such as an N-type doped polysilicon layer or a phosphorus-doped polysilicon layer, and the vertical axis of FIG. 2 represents the efficiency of the solar cell. The order of the curves in FIG. 2 from bottom to top corresponds to the following 15 spacings between adjacent N-type collector grid lines: 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, 1.391 mm, 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, and 0.839 mm. In FIG. 2, the solar cells having an efficiency greater than or equal to 26%, such as 26.0% to 26.5%, are selected as the solar cells having a relatively high efficiency, i.e., the portion enclosed by the dashed box in FIG. 2. The portion below the dashed box in FIG. 2 corresponds to the solar cells having an efficiency less than 26%. From FIG. 2, it can be seen that the solar cells having a spacing between adjacent N-type collector grid lines greater than or equal to 1.391 mm, i.e., 1.964 mm, 1.78 mm, 1.628 mm, 1.5 mm, and 1.391 mm, and / or the solar cells having a sheet resistance of the N-type doped layer 1 less than 14 ohms / square or greater than 40 ohms / square have an efficiency less than 26%. This indicates that the solar cells cannot have a relatively high efficiency when the spacing between adjacent N-type collector grid lines is greater than or equal to 1.391 mm and / or the sheet resistance of the N-type doped layer 1 is less than 14 ohms / square or greater than 40 ohms / square. Therefore, in the present application, the spacing between adjacent N-type collector grid lines is selected to be less than 1.391 mm and the sheet resistance of the N-type doped layer 1 is selected to be 14 ohms / square to 40 ohms / square, which is beneficial to improving the efficiency of the solar cell. As shown in FIG. 2, when the spacing between adjacent N-type collector grid lines is less than 1.391 mm and the sheet resistance of the N-type doped layer 1 is 14 ohms / square to 40 ohms / square, the solar cell has an efficiency greater than or equal to 26%, or even up to 26.5% or more.

[0114] Referring to FIG. 2, the sheet resistance of the N-type doped layer 1 is 20 ohm / square, and the efficiency of the solar cell is greater than or equal to 26% in the range of the sheet resistance of the N-type doped layer 1. More specifically, in the range of the sheet resistance of the N-type doped layer 1 being 14 ohm / square to 20 ohm / square and the distance between the adjacent N-type collector grid lines being 1.019 mm to 1.296 mm, the efficiency of the solar cell is greater than or equal to 26.0%, and the rate of increase in the efficiency is the fastest. In some embodiments, in the range of the sheet resistance of the N-type doped layer 1 being greater than 20 ohm / square to less than or equal to 40 ohm / square and the distance between the adjacent N-type collector grid lines being 0.839 mm to 0.977 mm, the efficiency of the solar cell is greater than or equal to 26.0%, and the rate of decrease in the efficiency is the slowest. Therefore, in the present application, the sheet resistance of the N-type doped layer 1 is 14 ohm / square to 20 ohm / square, and the distance between the adjacent N-type collector grid lines is 1.019 mm to 1.296 mm; or, the sheet resistance of the N-type doped layer 1 is greater than 20 ohm / square to less than or equal to 40 ohm / square, and the distance between the adjacent N-type collector grid lines is 0.839 mm to 0.977 mm. By further combining the sheet resistance of the N-type doped layer 1 and the distance between the adjacent N-type collector grid lines, the efficiency of the solar cell is further improved.

[0115] For example, the sheet resistance of the N-type doped layer 1 can be 14 ohm / square, 14.7 ohm / square, 15 ohm / square, 15.3 ohm / square, 16 ohm / square, 16.5 ohm / square, 17 ohm / square, 17.7 ohm / square, 18 ohm / square, 18.5 ohm / square, 19 ohm / square, 19.5 ohm / square, 20 ohm / square, and the distance between the adjacent N-type collector grid lines can be 1.019 mm, 1.05 mm, 1.076 mm, 1.112 mm, 1.141 mm, 1.173 mm, 1.213 mm, 1.25 mm, 1.296 mm. Or, the sheet resistance of the N-type doped layer 1 can be 20.3 ohm / square, 20.7 ohm / square, 21 ohm / square, 21.3 ohm / square, 22 ohm / square, 22.5 ohm / square, 23 ohm / square, 23.5 ohm / square, 24 ohm / square, 24.5 ohm / square, 25 ohm / square, 25.6 ohm / square, 27 ohm / square, 28 ohm / square, 29.6 ohm / square, 30 ohm / square, 31.6 ohm / square, 36.2 ohm / square, 38.56 ohm / square, 40 ohm / square, and the distance between the adjacent N-type collector grid lines can be 0.977 mm, 0.971 mm, 0.967 mm, 0.9 mm, 0.92 mm, 0.913 mm, 0.878 mm, 0.8 mm, 0.839 mm.

[0116] In some embodiments, the doping concentration of the N-type doped layer 1 is 3E20 cm -3 to 7E20 cm -3 Specifically, the doping concentration of the N-type doped layer 1 is an important factor affecting the sheet resistance of the N-type doped layer 1. In the present application, the doping concentration of the N-type doped layer 1 is limited within a more appropriate range, so that the sheet resistance of the N-type doped layer 1 can be within the aforementioned required range.

[0117] For example, the doping concentration of the N-type doped layer 1 can be 3E20 cm -3 , 3.2E20 cm -3 , 3.5E20 cm -3 , 4E20 cm -3 , 4.3E20 cm -3 , 4.7E20 cm -3 , 4.21E20 cm -3 , 5E20 cm -3 , 5.2E20 cm -3 , 5.5E20 cm -3 , 6E20 cm -3 , 6.3E20 cm -3 , 7E20 cm -3 .

[0118] The solar cell further comprises a plurality of P-type collecting grid lines 6 spaced and parallel, located on the side of the P-type doped layer 5 away from the silicon substrate 3; the spacing between adjacent P-type collecting grid lines 6 is less than or equal to the spacing between adjacent N-type collecting grid lines, which can further improve the efficiency of the solar cell. For example, the spacing between adjacent P-type collecting grid lines 6 is equal to the spacing between adjacent N-type collecting grid lines; or, the spacing between adjacent P-type collecting grid lines 6 is less than the spacing between adjacent N-type collecting grid lines.

[0119] In some embodiments, as can be seen from FIG. 5, when the spacing between adjacent P-type collecting grid lines 6 is less than 1.391 mm, the performance of the solar cell is relatively good, and the efficiency of the solar cell is relatively high, reaching 26% or more. For example, the spacing between adjacent P-type collecting grid lines 6 can be: 1.296 mm, 1.213 mm, 1.141 mm, 1.076 mm, 1.019 mm, 0.99 mm, 0.977 mm, 0.967 mm, 0.92 mm, 0.878 mm, 0.839 mm.

[0120] In some embodiments, the solar cell further comprises: a first tunneling oxide layer 4 between the N-type doped layer 1 and the silicon substrate 3; and a second tunneling oxide layer 9 between the P-type doped layer 5 and the silicon substrate 3. The second tunneling oxide layer 9 and the first tunneling oxide layer 4 can be formed in the same process, or the second tunneling oxide layer 9 and the first tunneling oxide layer 4 can be formed in different processes, which is not specifically limited. In the case that the second tunneling oxide layer 9 and the first tunneling oxide layer 4 are formed in different processes, whether the first tunneling oxide layer 4 is formed first or the second tunneling oxide layer 9 is formed first is not specifically limited. For example, the first tunneling oxide layer 4 can be formed first, and then the second tunneling oxide layer 9 is formed.

[0121] In some embodiments, the spacing between the first conductive region and the second conductive region is used to avoid electric leakage, and the relative size of the first conductive region and the second conductive region is not limited.

[0122] In some embodiments, the N-type doped layer 1 is an N-type doped polysilicon layer, and the P-type doped layer is a P-type doped polysilicon layer. The thickness of the P-type doped layer 5 is greater than or equal to the thickness of the N-type doped layer 1. Specifically, it can be difficult to obtain a high doping concentration for the P-type doped layer 5, and the P-type doped layer 5 has a higher sheet resistance. In order to reduce the sheet resistance, the thickness of the P-type doped layer 5 is appropriately thicker, which further improves the efficiency of the solar cell. For example, the thickness of the P-type doped layer 5 can be 100 nm to 500 nm, further 200 nm to 400 nm, such as 300 nm. For another example, the thickness of the N-type doped layer 1 can be 80 nm to 400 nm, further 150 nm to 300 nm, such as 200 nm.

[0123] The solar cell of the third aspect will be further explained in combination with specific embodiments.

[0124] Referring to the TBC (TopCon-Back Contact) cell shown in Figure 8, the N-type doped layer 1 is an N-type doped polycrystalline silicon layer with a thickness of 100 nm to 400 nm, such as approximately 200 nm. The P-type doped layer 5 is a P-type doped polycrystalline silicon layer with a thickness of 100 nm to 500 nm, such as 300 nm. The spacing between adjacent N-type collector lines 2 and adjacent P-type collector lines 6 is 0.839 to 0.977 mm, such as approximately 0.92 mm. The sheet resistance of the N-type doped layer 1 is 14 ohms / cubic to 50 ohms / cubic, and can further be 20 ohms / cubic to 40 ohms / cubic. For example, it can be 24 ohms / cubic. The sheet resistance of the P-type doped layer is 50 ohms / cubic to 200 ohms / cubic, or 50 ohms / cubic to 120 ohms / cubic. For example, it can be 90 ohms / cubic meter. The doping concentration of the N-type doped layer is 2E20cm³. -3 up to 7E21cm -3 For example, 6E20cm -3 The doping concentration for redoping a p-type doped layer is 2E19cm⁻¹. -3 up to 5E20cm -3 For example, 6E19cm -3 The doping concentration for shallow doping of the P-type doped layer is 2E18cm. -3 Up to 5E19cm -3 For example, 6E18cm -3 The silicon substrate is an N-type silicon substrate. The inward expansion of the N-type doped layer 1 into the silicon substrate is stronger than that of the P-type doped layer. For example, the inward expansion of the N-type doped layer 1 into the silicon substrate reaches E17cm. -3 up to 8E20cm -3 The P-type doped layer extends into the silicon substrate to a depth of E16cm. -3 Up to 5E19cm -3 .

[0125] The other films in the solar cell of the third aspect are not limited; for example, the description of the other films in the solar cell of the first aspect can be referred to. The specific parameter range of the remaining layers or structures in the solar cell of the second aspect is not limited; for example, the relevant description in the solar cell of the first aspect can be further referred to.

[0126] In some embodiments, the grid line width of the solar cell and the width of the N-type doped layer or the P-type doped layer have a proportional relationship. When the ratio of the width of the N-type doped layer or the P-type doped layer to the grid line width is in the range of 10-35, the requirements of carrier transport can be met, the cost of grid line preparation can be reduced, and the contact performance of the doped layer and the electrode can be improved. For the TBC cell, when the N-type substrate is a silicon substrate, the P-type doped layer and the N-type substrate form an emitter. In order to ensure the generation of carriers, the width of the P-type doped layer is greater than the width of the N-type doped layer. Therefore, the ratio of the width of the P-type doped layer to the grid line width is slightly greater than the ratio of the width of the N-type doped layer to the grid line width. For example, the ratio of the width of the N-type doped layer or the P-type doped layer to the grid line width can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, or 35.

[0127] It should be noted that the solar cells of the first aspect, the second aspect, and the third aspect described above all at least achieve a better balance among factors such as parasitic absorption, recombination current of the metal region, and lateral resistance in the solar cell, so that the performance of the solar cell is better and the photoelectric conversion efficiency is higher. Therefore, the solar cells belong to the same application concept.

[0128] The application also provides a photovoltaic module. The photovoltaic module includes a plurality of cell strings, the cell strings include a plurality of solar cells and a plurality of interconnects, the interconnects are used to connect the plurality of solar cells in series; the solar cell includes any one of the solar cells described above. The photovoltaic module can also include other structures, for example, the photovoltaic module can also include encapsulating adhesive films located on opposite sides of the solar cell. The other structures of the photovoltaic module are not limited. The photovoltaic module has the same or similar beneficial effects as the solar cells described above. In order to avoid repetition, the other structures of the photovoltaic module will not be described here. The interconnects can include solder strips and conductive interconnects. The interconnects are electrically connected to the positive electrode of a first solar cell and the negative electrode of a second solar cell adjacent to the first solar cell, so as to connect the two solar cells in series.

[0129] It should be noted that, for the method embodiments, in order to simply describe, the method embodiments are described as a series of action combinations, but those skilled in the art should know that the application embodiments are not limited by the order of the actions described, because according to the application embodiments, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification all belong to preferred embodiments, and the actions involved are not necessarily essential to the application embodiments.

Claims

1. A solar cell, wherein, Comprising: a silicon substrate; the silicon substrate comprises opposite first and second surfaces; an N-type doped layer on at least a partial region of the first surface of the silicon substrate; the sheet resistance of the N-type doped layer is 14 ohm / square to 40 ohm / square; a plurality of N-type collector grid lines spaced and parallel distributed on a side of the N-type doped layer facing away from the silicon substrate, the spacing between adjacent N-type collector grid lines is less than 1.391 mm.

2. The solar cell of claim 1, wherein, the sheet resistance of the N-type doped layer is 14 ohm / square to 20 ohm / square, and the spacing between adjacent N-type collector grid lines is 1.019 mm to 1.296 mm; or, the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square, and the spacing between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm.

3. The solar cell of claim 1, wherein, the thickness of the N-type doped layer is 100 nm to 140 nm.

4. The solar cell of claim 1, wherein, The N-type doped layer has a doping concentration of 3E20 cm -3 to 7E20 cm -3 .

5. The solar cell according to any one of claims 1 to 4, wherein Further comprising: a P-type doped layer, the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square; a plurality of P-type collector grid lines spaced and parallel distributed on a side of the P-type doped layer facing away from the silicon substrate.

6. The solar cell of claim 5, wherein, the N-type doped layer comprises an N-type doped polysilicon layer and / or an N-type doped microcrystalline silicon layer; the solar cell further comprises a first tunneling oxide layer between the N-type doped layer and the silicon substrate; the spacing between adjacent P-type collector grid lines is less than or equal to the spacing between adjacent N-type collector grid lines.

7. The solar cell of claim 6, wherein, the first surface comprises first and second spaced conductive regions; the N-type doped layer is on the first conductive region; the P-type doped layer is on the second conductive region; the solar cell further comprises a second tunneling oxide layer between the P-type doped layer and the silicon substrate.

8. The solar cell of claim 6, wherein, the N-type doped layer is on the first surface of the silicon substrate, and the P-type doped layer is on the second surface of the silicon substrate.

9. The solar cell of claim 5, wherein, the P-type doped layer is a P-type polysilicon doped layer and / or a P-type doped microcrystalline silicon layer.

10. A solar cell, wherein, Comprising: a silicon substrate; the silicon substrate comprises opposite light-receiving and back surfaces; an N-type doped layer on the back surface of the silicon substrate; the thickness of the N-type doped layer is 100 nm to 140 nm; a plurality of N-type collector grid lines spaced and parallel distributed on a side of the N-type doped layer facing away from the silicon substrate, the spacing between adjacent N-type collector grid lines is less than 1.391 mm; a P-type doped layer on the light-receiving surface of the silicon substrate; a plurality of P-type collector grid lines spaced and parallel distributed on a side of the P-type doped layer facing away from the silicon substrate, the spacing between adjacent P-type collector grid lines is less than or equal to the spacing between adjacent N-type collector grid lines.

11. The solar cell of claim 10, wherein, the spacing between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm.

12. The solar cell of claim 10, wherein, the N-type doped layer is on a partial region of the back surface of the silicon substrate.

13. The solar cell of claim 10, wherein, The N-type doped layer has a doping concentration of 3E20 cm -3 to 7E20 cm -3 .

14. The solar cell of any one of claims 10 to 13, wherein, the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square; and / or, the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square; and / or, the pitch between adjacent P-type collector grid lines is less than 1.391 mm.

15. A solar cell, wherein, comprising: a silicon substrate; the silicon substrate comprises a light-receiving side and a back side; the back side comprises: first and second electrically conductive regions distributed at intervals; an N-type doped layer on the first electrically conductive regions; the sheet resistance of the N-type doped layer is greater than 14 ohm / square and less than or equal to 40 ohm / square; a P-type doped layer on the second electrically conductive regions; the sheet resistance of the P-type doped layer is 20 ohm / square to 166 ohm / square; a plurality of N-type collector grid lines distributed at intervals and in parallel on a side of the N-type doped layer facing away from the silicon substrate; the pitch between adjacent N-type collector grid lines is less than 1.391 mm.

16. The solar cell of claim 15, wherein, the sheet resistance of the N-type doped layer is greater than 20 ohm / square and less than or equal to 40 ohm / square; the pitch between adjacent N-type collector grid lines is 0.839 mm to 0.977 mm.

17. The solar cell of claim 15, wherein, The N-type doped layer has a doping concentration of 3E20 cm -3 to 7E20 cm -3 .

18. The solar cell of claim 15, wherein, further comprising: a plurality of P-type collector grid lines distributed at intervals and in parallel on a side of the P-type doped layer facing away from the silicon substrate; the pitch between adjacent P-type collector grid lines is less than or equal to the pitch between adjacent N-type collector grid lines; and / or, the pitch between adjacent P-type collector grid lines is less than 1.391 mm.

19. The solar cell according to any one of claims 15 to 18, wherein, further comprising: a first tunneling oxide layer between the N-type doped layer and the silicon substrate; a second tunneling oxide layer between the P-type doped layer and the silicon substrate.

20. A photovoltaic module, wherein, A photovoltaic module comprises a plurality of cell strings, the cell strings comprising a plurality of solar cells and a plurality of interconnects for connecting the plurality of solar cells in series; wherein the solar cells are any one of claims 1-19.

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