Solar cell and photovoltaic module

Abstract

The invention discloses a solar cell and a photovoltaic module, relates to the technical field of photovoltaics, and is used for solving the problems of the current collection capability of electrodes and the reliability of electrode connection. The solar cell includes: a silicon substrate; the doped semiconductor layer is arranged on at least one surface of the silicon substrate; the passivation anti-reflection layer is arranged on the surface, away from the silicon substrate, of the doped semiconductor layer, and the passivation anti-reflection layer comprises an electrode overlapping area and a non-electrode overlapping area; the electric combination part is arranged on the surface, far away from the silicon substrate, of the passivation anti-reflection layer; a part of the current collection grid lines cover a part of the surface, far away from the silicon substrate, of the electric combination part; wherein the electrode overlapping area corresponds to the overlapping part of the electric combination part and the current collection grid line, the non-electrode overlapping area corresponds to the non-overlapping part of the electric combination part and the current collection grid line, and metal crystals exist in the electrode overlapping area. The metal crystal is arranged in the electrode overlapping area of the passivation anti-reflection layer, so that the current collecting efficiency of the current collecting grid line can be improved, and the reliability of electrode connection is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and particularly to a solar cell and a photovoltaic module. Background Art

[0002] A solar cell mainly includes a substrate and electrodes. Among them, the substrate includes a silicon substrate, and a doping layer and a passivation and antireflection layer sequentially disposed on one surface of the silicon substrate. The electrodes include current collecting grid lines, which are disposed on the silicon substrate and in contact with the doping layer for collecting current. The current collecting grid lines are connected to a conductive interconnecting member through an electrical bonding portion, and the current is collected and then led out. How to improve the current collecting ability of the electrodes and the reliability of the electrode connection has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0003] The purpose of the present invention is to provide a solar cell and a photovoltaic module to improve the current collecting ability of the electrodes and the reliability of the electrode connection.

[0004] In a first aspect, the present invention provides a solar cell, comprising:

[0005] A silicon substrate having two opposite surfaces;

[0006] A doped semiconductor layer disposed on at least one surface of the silicon substrate;

[0007] A passivation and antireflection layer disposed on the surface of the doped semiconductor layer away from the silicon substrate, the passivation and antireflection layer including an electrode overlapping region and a non-electrode overlapping region;

[0008] An electrical bonding portion disposed on the surface of the passivation and antireflection layer away from the silicon substrate;

[0009] Current collecting grid lines, and a part of the current collecting grid lines covering a part of the surface of the electrical bonding portion away from the silicon substrate;

[0010] Wherein, the electrode overlapping region corresponds to the overlapping part of the electrical bonding portion and the current collecting grid lines, the non-electrode overlapping region corresponds to the non-overlapping part of the electrical bonding portion and the current collecting grid lines, and metal crystals exist in the electrode overlapping region.

[0011] In the case of adopting the above technical solution,

[0012] The function of the electrical junction is to collect the current collected in the current collection grid lines. Therefore, there is usually no need to provide metal crystals in the electrical junction that are in contact with the doped semiconductor layer. In this application, providing metal crystals in the electrode overlapping region of the passivation and antireflection layer can, on the one hand, increase the contact area between the current collection grid lines and the doped semiconductor layer, thereby improving the efficiency of the current collection grid lines in collecting current. On the other hand, forming metal crystals in the passivation and antireflection layer below the electrical junction can enhance the bonding force between the electrode and the doped semiconductor layer, improving the reliability of the electrode connection. In addition, during the series soldering of the component ends, since the current collection grid lines cover a part of the surface of the electrical junction that is away from the silicon substrate, the interconnecting member can be directly connected to the current collection grid lines. Compared with the traditional conductive structure "current collection grid line - pad - current guiding bar", the intermediate conductive process through the electrical junction is reduced, the current loss is reduced, and the component power can be effectively improved.

[0013] In some possible implementation manners, the number of metal crystals in the electrode overlapping region is greater than the number of metal crystals in the non - electrode overlapping region.

[0014] In the case of adopting the above - mentioned technical solution, the relatively large number of metal crystals in the electrode overlapping region can enable the current collection grid lines to form an ohmic contact with the doped semiconductor layer in the electrode overlapping region, realizing the collection of carriers in the corresponding electrode overlapping region of the doped semiconductor layer and improving the photoelectric conversion efficiency of the battery. The relatively small number of metal crystals in the non - electrode overlapping region causes less damage to the passivation and antireflection layer in this region, the passivation loss is relatively slight, and the impact on the photoelectric conversion efficiency of the battery is slight.

[0015] In some possible implementation manners, the area of the orthographic projection of the metal crystals in the electrode overlapping region on the electrode overlapping region accounts for 10% - 60% of the area of the electrode overlapping region;

[0016] And / or, the area of the orthographic projection of the metal crystals in the non - electrode overlapping region on the non - electrode overlapping region accounts for 0% - 10% of the area of the non - electrode overlapping region.

[0017] In the case of adopting the above - mentioned technical solution, when the area ratio of the metal crystals in the electrode overlapping region is less than 10%, it is not conducive to the formation of an ohmic contact between the current collection grid lines and the doped semiconductor layer in the corresponding electrode overlapping region, and is not conducive to the current collection efficiency in this region. If the area ratio of the metal crystals in the electrode overlapping region is greater than 60%, the bonding area between the electrode overlapping region and the electrical junction will be too small, reducing the bonding reliability between the electrical junction and the electrode overlapping region. If the area ratio of the metal crystals in the non - electrode overlapping region is greater than 10%, the damage to the passivation and antireflection layer in this region will increase, the passivation effect will decrease, and the photoelectric conversion effect of the battery will be affected.

[0018] In some possible implementation manners, the doped semiconductor layer includes a first doped semiconductor layer and a second doped semiconductor layer, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conduction types;

[0019] The passivation and antireflection layer includes a first passivation and antireflection layer on the first doped semiconductor layer and a second passivation and antireflection layer on the second doped semiconductor layer. Both the first passivation and antireflection layer and the second passivation and antireflection layer include an electrode overlapping region and a non-electrode overlapping region;

[0020] The number of metal crystals in the electrode overlapping region of the first passivation and antireflection layer is greater than the number of metal crystals in the electrode overlapping region of the second passivation and antireflection layer.

[0021] In the case of adopting the above technical solution, the number of metal crystals in the passivation and antireflection layers corresponding to doped semiconductor layers of different conduction types is different. The number of metal crystals in the electrode overlapping region of the first passivation and antireflection layer is greater than the number of metal crystals in the electrode overlapping region of the second passivation and antireflection layer, which can enhance the contact effect between the first doped semiconductor layer and the corresponding electrode, and is more beneficial to the current collection efficiency of the electrode overlapping region corresponding to the first doped semiconductor layer.

[0022] In some possible implementation manners, the number of metal crystals in the electrode overlapping region is less than the number of metal crystals in the part of the passivation and antireflection layer that overlaps with the current collecting grid line and excludes the electrode overlapping region.

[0023] In the case of adopting the above technical solution, since part of the current collecting grid line covers part of the surface of the electrical bonding part, and part of the current collecting grid line covers part of the surface of the passivation and antireflection layer other than the electrical bonding part. Among them, the current collecting grid line covering the passivation and antireflection layer is used to collect the current of the underlying doped semiconductor layer. Therefore, the metal crystals of the current collecting grid line that need to cover the passivation and antireflection layer can penetrate through the passivation and antireflection layer to contact the underlying doped semiconductor layer more, so as to improve the current collection ability. For the current collecting grid line covering the electrical bonding part, since the main function of the electrical bonding part is to collect the current of the current collecting grid line, metal crystals in contact with the doped semiconductor layer are usually not required in the electrical bonding part. Therefore, the number of metal crystals in the electrode overlapping region corresponding to the electrical bonding part is small, which is to improve the contact performance of the electrical bonding part while not damaging the bonding force between the electrical bonding part and the passivation and antireflection layer, and reducing the risk of the electrical bonding part falling off.

[0024] In some possible implementation manners, the electrical bonding part is intermittently arranged along a direction perpendicular to the extending direction of the current collecting grid line.

[0025] In the case of adopting the above technical solution, the electrical junction part may not adopt the main grid and is connected to the current collecting grid line through the discontinuous electrical junction part. At this time, the contact area between the electrical junction part and the passivation and antireflection layer is reduced. Therefore, setting metal crystals in the electrode overlapping area can make up for the loss of contact performance and electrode tensile force caused by the discontinuous setting of the electrical junction part, thereby improving the battery efficiency.

[0026] In some possible implementation manners, the height of the electrical junction part in the electrode overlapping area is less than the height of the electrical junction part in the non-electrode overlapping area.

[0027] In the case of adopting the above technical solution, since the height of the overlapping part of the electrical junction part and the current collecting grid line is reduced relative to the height of the rest of the electrical junction part, the distance between the current collecting grid line covering the electrical junction part and the passivation and antireflection layer is reduced, which can reduce the difficulty of forming metal crystals by the current collecting grid line in the lower electrode overlapping area.

[0028] In some possible implementation manners, the surface of the electrode overlapping area has a corrosion area;

[0029] The doped semiconductor layer includes a first doped semiconductor layer and a second doped semiconductor layer, and the conductive types of the first doped semiconductor layer and the second doped semiconductor layer are opposite;

[0030] The passivation and antireflection layer includes a first passivation and antireflection layer on the first doped semiconductor layer and a second passivation and antireflection layer on the second doped semiconductor layer. Both the first passivation and antireflection layer and the second passivation and antireflection layer include an electrode overlapping area and a non-electrode overlapping area;

[0031] The area ratio of the corrosion area of the first passivation and antireflection layer in the corresponding electrode overlapping area is greater than the area ratio of the corrosion area of the second passivation and antireflection layer in the corresponding electrode overlapping area.

[0032] In the case of adopting the above technical solution, the area ratios of the corrosion areas in the passivation and antireflection layers corresponding to the doped semiconductor layers of different conductive types are different. The area ratio of the corrosion area of the first passivation and antireflection layer is greater than the area ratio of the corrosion area of the second passivation and antireflection layer, which can enable the current collecting grid line to be in more direct or indirect contact with the first doped semiconductor layer, enhance the contact effect between the first doped semiconductor layer and the corresponding electrode, and be more conducive to the current collection efficiency of the electrode overlapping area corresponding to the first doped semiconductor layer.

[0033] In some possible implementation manners, the area ratio of the corrosion area of the first passivation and antireflection layer is 80% - 100%;

[0034] And / or, the area ratio of the corrosion area of the second passivation and antireflection layer is 10% - 70%.

[0035] In the case of adopting the above technical solution, when the area ratio of the corrosion area of the first passivation and antireflection layer is less than 80%, it is not conducive to the contact performance between the collector grid line and the first doped semiconductor layer in the overlapping area with the corresponding electrode, and is not conducive to the current collection efficiency in this area. If the area ratio of the corrosion area of the first passivation and antireflection layer is less than 80%, it will cause the bonding area between the electrode overlapping area of the first passivation and antireflection layer and the electrical bonding part to be too small, reducing the bonding reliability between the electrical bonding part and the electrode overlapping area of the first passivation and antireflection layer. Similarly, considering the same reasons as the corrosion area of the first passivation and antireflection layer, the area ratio of the corrosion area of the second passivation and antireflection layer is selected to be 10% - 70%.

[0036] In some possible implementation manners, the corrosion area has contact holes penetrating the passivation and antireflection layer, and the metal crystals located in the contact holes are in contact with the doped semiconductor layer and / or the collector grid line.

[0037] In the case of adopting the above technical solution, the collector grid line covering the electrical bonding part can be in contact with the doped semiconductor layer through the metal crystals located in the contact holes of the passivation and antireflection layer to form an ohmic contact, improving the contact performance between the electrode and the doped semiconductor layer and improving the current collection efficiency in this area.

[0038] In some possible implementation manners, the surface of the non - electrode overlapping area far from the silicon substrate has blind holes that do not penetrate the passivation and antireflection layer;

[0039] Or, the surface of the non - electrode overlapping area far from the silicon substrate has blind holes that do not penetrate the passivation and antireflection layer, and there are metal crystals in the blind holes.

[0040] In the case of adopting the above technical solution, for the case where there are metal crystals in the blind holes, the bonding force between the electrical bonding part and the passivation and antireflection layer can be improved, reducing the risk of the electrical bonding part falling off.

[0041] In a second aspect, the present invention further provides a photovoltaic module. The photovoltaic module includes a plurality of battery strings. The battery string includes the solar cell described in any one of the above and an electrical connection line. The electrical connection line is disposed on the electrical bonding part and at least covers a part of the electrical bonding part; the electrical connection line is electrically connected to the electrical bonding part through a bonding material.

[0042] In the case of adopting the above technical solution, each solar cell of the battery string is connected in series through the connection between the electrical connection line and the electrical bonding part. Since the photovoltaic module adopts the solar cell in the first aspect and any one of the above implementation manners, the photovoltaic module has the same beneficial effects as those in the first aspect and any one of the above implementation manners, which will not be elaborated. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation to the present invention. In the drawings:

[0044] Figure 1 FIG. is a schematic structural diagram of a solar cell provided by an embodiment of the present invention;

[0045] Figure 2 FIG. is a schematic topographic diagram of an N-region electrode overlapping area of a solar cell provided by an embodiment of the present invention;

[0046] Figure 3 FIG. is a schematic topographic diagram of a P-region electrode overlapping area of a solar cell provided by an embodiment of the present invention.

[0047] Reference numerals: 1 is a silicon substrate, 2 is a doped semiconductor layer, 21 is a first doped semiconductor layer, 22 is a second doped semiconductor layer, 3 is a passivation and antireflection layer, 31 is a first passivation and antireflection layer, 32 is a second passivation and antireflection layer, 4 is an electrical bonding part, 41 is a first electrical bonding part, 42 is a second electrical bonding part, 5 is a collector grid line, 51 is a first collector grid line, 52 is a second collector grid line, 101 is an electrode overlapping area, 102 is a non-electrode overlapping area. Detailed embodiments

[0048] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0049] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0050] In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is two or more, unless otherwise specifically defined. The meaning of "several" is one or more, unless otherwise specifically defined.

[0051] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0052] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] A solar cell mainly includes a substrate and electrodes. Among them, the substrate includes a silicon substrate, a doping layer, and a passivation and antireflection layer that are sequentially disposed on one surface of the silicon substrate. The electrodes include collector grid lines. The collector grid lines are disposed on the silicon substrate and are in contact with the doping layer for collecting current. The collector grid lines are connected to a conductive interconnect through an electrical bonding portion to collect and conduct out the current. How to improve the current collection ability of the electrodes and the reliability of the electrode connection has become an urgent problem for those skilled in the art.

[0054] In view of this, as Figure 1 shown, an embodiment of the present invention provides a solar cell, including a silicon substrate 1, a doped semiconductor layer 2, a passivation and antireflection layer 3, an electrical bonding portion 4, and collector grid lines 5. Among them, the silicon substrate 1 has two opposite surfaces; the doped semiconductor layer 2 is disposed on at least one surface of the silicon substrate 1; the passivation and antireflection layer 3 is disposed on the surface of the doped semiconductor layer 2 away from the silicon substrate 1. The passivation and antireflection layer 3 includes an electrode overlapping region 101 and a non-electrode overlapping region 102; the electrical bonding portion 4 is disposed on the surface of the passivation and antireflection layer 3 away from the silicon substrate 1; a part of the collector grid lines 5 covers a part of the surface of the electrical bonding portion 4 away from the silicon substrate 1. Among them, the electrode overlapping region 101 corresponds to the overlapping part of the electrical bonding portion 4 and the collector grid lines 5, the non-electrode overlapping region 102 corresponds to the non-overlapping part of the electrical bonding portion 4 and the collector grid lines 5, and metal crystals exist in the electrode overlapping region 101.

[0055] It should be noted that the electrode overlapping region 101 and the non-electrode overlapping region 102 include not only the regions on the passivation and antireflection layer 3, but also the corresponding regions in the doped semiconductor layer 2 and the electrical bonding part 4. The existence of metal crystals in the electrode overlapping region 101 means that metal crystals can exist only in the electrode overlapping region 101 of the passivation and antireflection layer 3, or can exist simultaneously in the electrode overlapping regions 101 corresponding to the passivation and antireflection layer 3 and the doped semiconductor layer 2, or can exist simultaneously in the electrode overlapping regions 101 corresponding to the passivation and antireflection layer 3, the doped semiconductor layer 2 and the electrical bonding part 4.

[0056] Exemplarily, the printing sequence is controlled as "electrical bonding part - printing of N-region or P-region collector grid lines - printing of P-region or N-region collector grid lines". After each printing, it is dried once to cure the slurry. After 3 times of printing, sintering and light injection are carried out together to form a contact. Also, for example, the printing sequence is controlled as "electrical bonding part - printing of N-region and P-region collector grid lines". After each printing, it is dried once to cure the slurry. After 2 times of printing, sintering and light injection are carried out together to form a contact. The collector grid lines 5 penetrate or overlap above the electrical bonding part 4 through printing, forming a contact structure of collector grid line - electrical bonding part - doped semiconductor layer.

[0057] It should be noted that according to the surface structure characteristics of the solar cell to be observed, it is cleaned once, twice or multiple times with a cleaning solution to obtain the surface of the region to be observed. For example, the detection of metal crystals can be carried out in the following way: First, the metal grid lines and glass phase on the surface of the solar cell are removed by a cleaning solution (such as HNO 3 and / or HF), and the passivation and antireflection layer 3 is retained. Then, the region corresponding to the electrical bonding part 4 of the cleaned solar cell is observed and imaged by an electron microscope to observe the situation of metal crystals in this region. The area ratio of metal crystals (such as silver-silicon grains, nickel grains, copper grains, etc., determined according to the metal used for the electrode) can be calculated within 25μm 2 To reduce the influence of image acquisition resolution and software statistical error, metal crystals with a particle size less than 45nm are not included in the statistical range.

[0058] In the case of adopting the above technical solution, the function of the electrical junction part 4 is to collect the current collected in the current collecting grid line 5. Therefore, there is usually no need to arrange metal crystals in the electrical junction part 4 that are in contact with the doped semiconductor layer 2. In this application, arranging metal crystals in the electrode overlapping region 101 of the passivation and antireflection layer 3 can, on the one hand, expand the contact area between the current collecting grid line 5 and the doped semiconductor layer 2, improving the efficiency of the current collecting grid line 5 in collecting current; on the other hand, forming metal crystals in the passivation and antireflection layer 3 under the electrical junction part 4 can enhance the bonding force between the electrode and the doped semiconductor layer 2, improving the reliability of the electrode connection. In addition, during the end string soldering of the component, since the current collecting grid line 5 covers a part of the surface of the electrical junction part 4 away from the silicon substrate 1, the electrical junction part 4 blocks the large-area corrosion of the passivation and antireflection layer 3 by the highly corrosive glass frit in the paste of the current collecting grid line 5, which can maintain the bonding strength between the electrical junction part 4 and the battery chip, ensuring excellent soldering tensile force. And since the current collecting grid line 5 covers a part of the surface of the electrical junction part 4 away from the silicon substrate 1, the conductive interconnecting member (such as a solder strip) can be directly connected to the current collecting grid line 5. Compared with the traditional conductive structure "current collecting grid line - pad - current guiding strip", the intermediate conductive process through the electrical junction part is reduced, the current loss is reduced, and the power of the component can be effectively improved.

[0059] In some embodiments, the number of metal crystals in the electrode overlapping region 101 is greater than the number of metal crystals in the non-electrode overlapping region 102. The relatively large number of metal crystals in the electrode overlapping region 101 can enable the current collecting grid line 5 to form an ohmic contact with the doped semiconductor layer 2 in the electrode overlapping region 101, realizing the collection of carriers in the corresponding electrode overlapping region 101 of the doped semiconductor layer 2 and improving the photoelectric conversion efficiency of the battery. The relatively small number of metal crystals in the non-electrode overlapping region 102 causes less damage to the passivation and antireflection layer 3 in this region, the passivation loss is relatively slight, and the impact on the photoelectric conversion efficiency of the battery is slight.

[0060] In some embodiments, the area of the positive projection of the metal crystals in the electrode overlapping region 101 on the electrode overlapping region 101 accounts for 10% to 60% of the area of the electrode overlapping region 101, and specifically can be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, etc. If the area ratio of the metal crystals in the electrode overlapping region 101 is less than 10%, it is not conducive to forming an ohmic contact between the current collecting grid line 5 and the doped semiconductor layer 2 of the corresponding electrode overlapping region 101, and is not conducive to the current collection efficiency of this region. If the area ratio of the metal crystals in the electrode overlapping region 101 is greater than 60%, the bonding area between the electrode overlapping region 101 and the electrical bonding portion 4 will be too small, reducing the bonding reliability between the electrical bonding portion 4 and the electrode overlapping region 101. Therefore, considering improving the current collection efficiency of the electrode overlapping region and the bonding reliability of the electrical bonding portion, the area of the positive projection of the metal crystals in the electrode overlapping region 101 of this embodiment accounts for 10% to 60% of the area of the electrode overlapping region 101.

[0061] In some embodiments, the area of the positive projection of the metal crystals in the non-electrode overlapping region 102 on the non-electrode overlapping region 102 accounts for 0% to 10% of the area of the non-electrode overlapping region 102, and specifically can be 0%, 2%, 4%, 6%, 08%, 10%, etc. If the area ratio of the metal crystals in the non-electrode overlapping region 102 is greater than 10%, it will increase the damage to the passivation and antireflection layer 3 in this region, reduce the passivation effect, and affect the photovoltaic conversion effect of the battery.

[0062] As Figure 1 shown, in some embodiments, for a back-contact solar cell, the doped semiconductor layer 2 includes a first doped semiconductor layer 21 and a second doped semiconductor layer 22, and the conduction types of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are opposite; the passivation and antireflection layer 3 includes a first passivation and antireflection layer 31 on the first doped semiconductor layer 21 and a second passivation and antireflection layer 32 on the second doped semiconductor layer 22, and both the first passivation and antireflection layer 31 and the second passivation and antireflection layer 32 include an electrode overlapping region 101 and a non-electrode overlapping region 102; a first electrical bonding portion 41 and a first current collecting grid line 51 are provided on the first passivation and antireflection layer 31, and a second electrical bonding portion 42 and a second current collecting grid line 52 are provided on the second passivation and antireflection layer 32; the number of metal crystals in the electrode overlapping region 101 of the first passivation and antireflection layer 31 is greater than the number of metal crystals in the electrode overlapping region 101 of the second passivation and antireflection layer 32.

[0063] In the case of adopting the above technical solution, the number of metal crystals in the passivation and antireflection layer 3 corresponding to the doped semiconductor layer 2 of different conductivity types is different. The number of metal crystals in the electrode overlapping region 101 of the first passivation and antireflection layer 31 is greater than the number of metal crystals in the electrode overlapping region 101 of the second passivation and antireflection layer 32, which can enhance the contact effect between the first doped semiconductor layer 21 and the corresponding first collector grid line 51, and is more beneficial to the current collection efficiency of the first doped semiconductor layer 21 in the corresponding electrode overlapping region 101.

[0064] Exemplarily, the first doped semiconductor layer 21 can be a P-type doped semiconductor layer corresponding to the P region, and the second doped semiconductor layer 22 is an N-type doped semiconductor layer corresponding to the N region; or, the first doped semiconductor layer 21 can be an N-type doped semiconductor layer corresponding to the N region, and the second doped semiconductor layer 22 can be a P-type doped semiconductor layer corresponding to the P region. For example, the content of metal components and corrosive glass frit in the paste used for the collector grid line 5 on the P region is relatively high, while the content of metal components and corrosive glass frit in the paste used for the collector grid line 5 on the N region is relatively low. The collector grid line 5 contains highly corrosive glass frit, which has a corrosive effect on the passivation and antireflection layer 3, causing the metal components in the collector grid line 5 to enter the corroded structure of the passivation and antireflection layer 3 under the action of gravity to form metal crystals. Since the content of metal components and glass frit in the paste used for the collector grid line 5 on the P region is relatively high, the glass frit of the collector grid line 5 on the electrode overlapping region 101 of the passivation and antireflection layer 3 in the P region corrodes the passivation and antireflection layer 3 in this region more strongly and has more metal components. Therefore, the number of metal crystals formed in the corroded structure is relatively more and the density is greater than that in the N region. Then, the contact effect between the P-type doped semiconductor layer and the corresponding electrode can be enhanced, and it is more beneficial to the current collection efficiency of the P-type doped semiconductor layer in the corresponding electrode overlapping region 101.

[0065] It should be noted that the process of realizing different numbers of metal crystals in the passivation and antireflection layer 3 corresponding to the doped semiconductor layer 2 of different conductivity types can adopt using different electrode pastes in conductive regions of different doping types, or by adjusting process parameters such as sintering temperature and sintering time, which is not limited herein.

[0066] For non-back-contact solar cells, the conductivity types of the doped semiconductor layers 2 on the same surface of the silicon substrate 1 are the same, which can be a P-type doped semiconductor layer or an N-type doped semiconductor layer. The doped semiconductor layers with different doping types are located on the light-receiving surface and the backlight surface of the silicon substrate 1 that are oppositely arranged. As long as the electrical coupling part 4 and the collector grid line 5 are provided, there are an electrode overlapping region 101 and a non-electrode overlapping region 102. There are metal crystals in the electrode overlapping region 101, or the number of metal crystals in the electrode overlapping region 101 is greater than the number of metal crystals in the non-electrode overlapping region 102. For the technical effects, reference can be made to the beneficial effects described in the above embodiments, which will not be elaborated herein.

[0067] In some embodiments, the number of metal crystals in the electrode overlapping region 101 is less than the number of metal crystals in the portion of the passivation and antireflection layer 3 that overlaps with the collector grid line 5 and is other than the electrode overlapping region 101. Since a part of the collector grid line 5 covers a part of the surface of the electrical connection portion 4, and another part of the collector grid line 5 covers the surface of the passivation and antireflection layer 3 other than the electrical connection portion 4, that is, directly covers the passivation and antireflection layer 3. Among them, the collector grid line 5 directly covering the passivation and antireflection layer 3 is used to collect the current of the underlying doped semiconductor layer 2. Therefore, it is necessary for the metal crystals of the collector grid line 5 covering the passivation and antireflection layer 3 to pass through the passivation and antireflection layer 3 more to contact the underlying doped semiconductor layer 2, so as to improve the current collection ability. For the collector grid line covering the electrical connection portion 4, since the main function of the electrical connection portion 4 is to collect the current of the collector grid line 5, metal crystals in contact with the doped semiconductor layer 2 are usually not required to be provided in the electrical connection portion 4. Therefore, the number of metal crystals in the electrode overlapping region 101 corresponding to the electrical connection portion 4 on the passivation and antireflection layer 3 is greater than the number of metal crystals in the portion of the passivation and antireflection layer 3 directly covering the collector grid line 5, so as to improve the contact performance between the collector grid line 5 and the doped semiconductor layer 2 at the electrical connection portion 4 while not damaging the bonding force between the electrical connection portion 4 and the passivation and antireflection layer 3 and reducing the risk of the electrical connection portion 4 falling off.

[0068] It should be noted that the portion of the passivation and antireflection layer 3 that overlaps with the collector grid line 5 and is other than the electrode overlapping region 101 includes not only the region on the passivation and antireflection layer 3, but also the corresponding regions in the doped semiconductor layer 2 and the collector grid line 5. The existence of metal crystals in this part means that metal crystals can exist only in this part of the passivation and antireflection layer 3, or can exist simultaneously in this corresponding part of the passivation and antireflection layer 3 and the doped semiconductor layer 2, or can exist simultaneously in this corresponding part of the passivation and antireflection layer 3, the doped semiconductor layer 2 and the collector grid line 5.

[0069] In some embodiments, the electrical connection portion 4 is intermittently arranged along a direction perpendicular to the extending direction of the collector grid line 5. That is, at this time, the electrical connection portion 4 is a pad corresponding to the collector grid line 5, an end line corresponding to the vicinity of both ends of the collector grid line 5, or a thickened section corresponding to the collector grid line 5, as long as it can be electrically connected to the collector grid line 5 and can be electrically connected to a conductive interconnecting member, such as a solder ribbon.

[0070] In the case of adopting the above technical solution, the electrical connection portion 4 may not adopt a main grid line and is connected to the collector grid line 5 through an intermittent electrical connection portion 4 (such as a pad, an end line or a thickened section of the collector grid line, etc.). At this time, the contact area between the electrical connection portion 4 and the passivation and antireflection layer 3 is reduced. Therefore, setting metal crystals in the electrode overlapping region 101 can make up for the loss of conductive contact performance and electrode tensile force caused by the intermittent arrangement of the electrical connection portion 4, thereby improving the battery efficiency.

[0071] Of course, in some other embodiments, the electrical coupling portion 4 may further include continuous busbar grid lines, i.e., main grid lines. The extending direction of the main grid lines intersects with the extending direction of the current collecting grid lines, specifically, it may be perpendicular. One main grid line is connected to multiple current collecting grid lines. Structures such as pads, end lines, or thickened sections of the main grid lines that are convenient for connection with conductive interconnects may also be provided at the positions where the main grid lines are correspondingly connected to the current collecting grid lines. Of course, the electrical coupling portion 4 may also include only busbar grid lines. During preparation, the electrical coupling portion 4 (such as pads, busbar grid lines) may be printed first. After drying and curing, the current collecting grid lines 5 are printed, then cured, and finally sintered and photo-injected together to form contacts, so that the electrical coupling portion 4 blocks the corrosion of the passivation and antireflection layer 3 below the electrical coupling portion 4 by the highly corrosive glass frit in the current collecting grid lines 5, maintains the bonding strength between the electrical coupling portion 4 and the cell, ensures good welding tensile force, and makes it difficult for the conductive interconnects to fall off.

[0072] In some embodiments, the surface of the overlapping portion of the electrical coupling portion 4 and the current collecting grid lines 5 on the electrode overlapping region 101 is recessed toward the silicon substrate 1 relative to the surface of the non-overlapping portion of the electrical coupling portion 4 and the current collecting grid lines 5. That is, in the thickness direction of the silicon substrate 1, the height of the overlapping portion of the electrical coupling portion 4 and the current collecting grid lines 5 is less than the height of the remaining positions of the electrical coupling portion 4. Such a setting reduces the distance between the current collecting grid lines 5 covering the electrical coupling portion 4 and the passivation and antireflection layer 3. The glass frit of the current collecting grid lines 5 at this position is more likely to corrode through the underlying electrical coupling portion 4 and the passivation and antireflection layer 3 to contact the doped semiconductor layer 2, which can reduce the difficulty of forming metal crystals in the current collecting grid lines 5 within the underlying electrode overlapping region 101.

[0073] As Figure 2 and Figure 3 shown, in some possible implementation manners, the surface of the electrode overlapping region 101 has a corrosion region, that is, the surface of the passivation and antireflection layer 3 has a corrosion region corroded by the highly corrosive glass frit in the current collecting grid lines 5. The region where the surface of the passivation and antireflection layer 3 presents corrosion pits or corrosion penetration is the corrosion region. It should be noted that according to the surface structure characteristics of the solar cell to be observed, the surface at the electrical coupling portion to be observed is obtained by cleaning with a cleaning solution once, twice, or multiple times. For example, the corrosion region can be observed in the following way:

[0074] First, the metal grid lines, glass phase, and metal crystals on the surface of the solar cell are removed by a cleaning solution (such as HNO 3 ), and the passivation and antireflection layer 3 is retained. Then, the region corresponding to the electrical coupling portion of the cleaned solar cell is observed and imaged by an electron microscope, and the images as Figure 2 and Figure 3 shown are obtained. It can be seen that there are corrosion pits on the surface of the passivation and antireflection layer 3, and in some regions, the underlying doped semiconductor layer 2 is exposed.

[0075] Exemplarily, for a back-contact solar cell, the doped semiconductor layer 2 includes a first doped semiconductor layer 21 and a second doped semiconductor layer 22, and the conduction types of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are opposite; the passivation and antireflection layer 3 includes a first passivation and antireflection layer 31 on the first doped semiconductor layer 21 and a second passivation and antireflection layer 32 on the second doped semiconductor layer 22, and both the first passivation and antireflection layer 31 and the second passivation and antireflection layer 32 include an electrode overlapping region 101 and a non-electrode overlapping region 102; wherein, the area ratio of the corrosion region of the first passivation and antireflection layer 31 to the corresponding electrode overlapping region 101 is greater than the area ratio of the corrosion region of the second passivation and antireflection layer 32 to the corresponding electrode overlapping region 101.

[0076] In the case of adopting the above technical solution, the area ratios of the corrosion regions in the passivation and antireflection layers 3 corresponding to the doped semiconductor layers 2 of different conduction types are different, and the area ratio of the corrosion region of the first passivation and antireflection layer 31 is greater than the area ratio of the corrosion region of the second passivation and antireflection layer 32, which can enable the collector grid line 5 to be in more direct or indirect contact with the first doped semiconductor layer 21, enhance the contact effect between the first doped semiconductor layer 21 and the corresponding electrode, and be more beneficial to the current collection efficiency of the corresponding electrode overlapping region 101 of the first doped semiconductor layer 2. For example, the first doped semiconductor layer 21 is a P-type doped semiconductor layer corresponding to the P region, and the second doped semiconductor layer 22 is an N-type doped semiconductor layer corresponding to the N region. Since there is more highly corrosive glass frit in the paste used for the collector grid line 5 on the P region, the corrosion of the passivation and antireflection layer 3 of the P region is higher. Therefore, the area ratio of the corrosion region of the passivation and antireflection layer 3 of the P region is greater than the area ratio of the corrosion region of the passivation and antireflection layer 3 of the N region, which can enhance the contact effect between the P-type doped semiconductor layer and the corresponding electrode and be more beneficial to the current collection efficiency of the corresponding electrode overlapping region 101 of the P-type doped semiconductor layer.

[0077] It should be noted that the different areas of the corrosion regions in the passivation and antireflection layers 3 corresponding to the doped semiconductor layers 2 of different conduction types can be achieved by using different electrode pastes in different doped conductive regions, or by adjusting process parameters such as sintering temperature and sintering time, which are not limited herein.

[0078] Exemplarily, as Figure 3 shown, the area ratio of the corrosion region of the first passivation and antireflection layer 31 is 80% - 100%, specifically it can be 80%, 85%, 90%, 95%, 100%, etc.; as Figure 2 shown, the area ratio of the corrosion region of the second passivation and antireflection layer 32 is 10% - 70%, specifically it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, etc.

[0079] When the area ratio of the corrosion area of the first passivation and antireflection layer 31 is less than 80%, it is not conducive to the contact performance between the collector grid line 5 and the first doped semiconductor layer 21 in the overlapping region 101 of the corresponding electrode, and is not conducive to the current collection efficiency in this region. If the area ratio of the corrosion area of the first passivation and antireflection layer 31 is less than 80%, the bonding area between the electrode overlapping region 101 of the first passivation and antireflection layer 31 and the first electrical bonding part 41 will be too small, reducing the bonding reliability between the electrical bonding part 41 and the electrode overlapping region 101 of the first passivation and antireflection layer 31. Similarly, considering the same reasons as the corrosion area of the first passivation and antireflection layer 31, the area ratio of the corrosion area of the second passivation and antireflection layer 32 is selected to be 10% - 70%.

[0080] In some embodiments, the corrosion area has contact holes penetrating the passivation and antireflection layer 3, and the metal crystals located in the contact holes are in contact with the doped semiconductor layer 2 and / or the collector grid line 5. That is, in the corroded area of the passivation and antireflection layer 3, a part penetrates through the passivation and antireflection layer 3 to form contact holes. The contact holes are formed by the highly corrosive glass frit of the collector grid line 5, and the metal material in the collector grid line 5 enters the contact holes to form metal crystals. The collector grid line 5 covering the electrical bonding part 4 can be in contact with the doped semiconductor layer 2 through the metal crystals located in the contact holes of the passivation and antireflection layer 3 to form an ohmic contact, improving the contact performance between the electrode and the doped semiconductor layer 2 and the current collection efficiency in this region. Of course, in the presence of contact holes, there may or may not be metal crystals in the contact holes. If there are metal crystals in the contact holes, the metal crystals in the contact holes can be in contact only with the collector grid line 5, or only with the doped semiconductor layer 2, or in contact with both the collector grid line 5 and the doped semiconductor layer 2, or in contact with neither the collector grid line 5 nor the doped semiconductor layer 2. These situations can appear on the solar cell in any combination.

[0081] It should be noted that the contact holes can be observed in the following ways:

[0082] First, use a cleaning solution to remove the metal grid lines, glass phase, and metal crystals on the surface of the solar cell, and retain the passivation and antireflection layer 3 corroded by the glass frit. Then, observe and collect images of the area corresponding to the electrical bonding part 4 of the cleaned solar cell through an electron microscope to observe the contact holes. To reduce the influence of image acquisition resolution and software statistical errors, holes with a diameter less than 45 nm are not included in the statistical range of the contact holes. Among them, the cleaning solution can use corrosive solutions such as HNO 3 、HF, etc.

[0083] In some embodiments, the surface of the non - electrode overlapping region 102 of the passivation and antireflection layer 3, which is away from the silicon substrate 1, has blind holes that do not penetrate through the passivation and antireflection layer 3. The orifice of the blind hole faces away from the silicon substrate 1, and there may be no metal crystals in this blind hole. Alternatively, there are metal crystals in the blind hole. Since the non - electrode overlapping region 102 does not overlap with the collector grid line 5, there is no situation where it is corroded by the corrosive glass frit in the collector grid line 5 or the degree of corrosion is very weak. After being corroded, non - penetrating blind holes are formed, and at this point, there is no need to arrange metal crystals in the electrical bonding part 4 to contact the underlying doped semiconductor layer 2. Therefore, there may be no metal crystals in the blind hole, or there are fewer metal crystals. The roughness of the passivation and antireflection layer 3 can be increased through the blind holes, which is beneficial for some materials of the electrical bonding part 4 to enter the blind hole to increase the bonding strength between the electrical bonding part 4 and the passivation and antireflection layer 3, and reduce the risk of the electrical bonding part 4 falling off.

[0084] In some possible implementation manners, the surface of the doped semiconductor layer 2 corresponding to the electrode overlapping region 101 has corrosion pits. The corrosion pits on the doped semiconductor layer 2 are also formed by the highly corrosive glass frit in the collector grid line 5, indicating that the passivation and antireflection layer 3 above the region of the doped semiconductor layer 2 with corrosion grooves is also corroded away. The region of the corrosion pits on the doped semiconductor layer 2 is in direct contact with the collector grid line 5 to form an ohmic contact, realizing carrier collection and improving the photoelectric conversion efficiency of the battery.

[0085] In some embodiments, the doped semiconductor layer 2 includes a first doped semiconductor layer 21 and a second doped semiconductor layer 22, and the conduction types of the first doped semiconductor layer 21 and the second doped semiconductor layer 22 are opposite; the passivation and antireflection layer 3 includes a first passivation and antireflection layer 31 on the first doped semiconductor layer 21 and a second passivation and antireflection layer 32 on the second doped semiconductor layer 22. Both the first passivation and antireflection layer 31 and the second passivation and antireflection layer 32 include an electrode overlapping region 101 and a non - electrode overlapping region 102; both the first doped semiconductor layer 21 and the second doped semiconductor layer 22 have corrosion pits, and the area ratio of the corrosion pits of the first doped semiconductor layer 21 on the corresponding electrode overlapping region 101 is greater than the area ratio of the corrosion pits of the second doped semiconductor layer 22 on the corresponding electrode overlapping region 101. Specifically, the area ratio of the corrosion pits of the first doped semiconductor layer 21 on the corresponding electrode overlapping region 101 is 0% - 30%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, etc.; the area ratio of the corrosion pits of the second doped semiconductor layer 22 on the corresponding electrode overlapping region 101 is 0% - 15%, for example, it can be 0%, 5%, 10%, 15%, etc.

[0086] In the case of adopting the above technical solution, the area ratio of the corrosion pits of the first doped semiconductor layer 21 is greater than that of the corrosion pits of the second doped semiconductor layer 22, which can enhance the contact effect between the first doped semiconductor layer 21 and the first collector grid line 51. For example, the first doped semiconductor layer 21 is a P-type doped semiconductor layer corresponding to the P region, and the second doped semiconductor layer 22 is an N-type doped semiconductor layer corresponding to the N region. Since there is more highly corrosive glass frit in the paste used for the collector grid line 5 on the P region, the corrosion resistance of the passivation and antireflection layer 3 and the doped semiconductor layer 2 on the P region is higher. Therefore, the area ratio of the corrosion region of the P-type doped semiconductor layer is greater than that of the corrosion region of the N-type doped semiconductor layer, which can enhance the contact effect between the P-type doped semiconductor layer and the corresponding electrode, and is more conducive to the current collection efficiency of the overlapping region of the P-type doped semiconductor layer and the corresponding electrode.

[0087] In some embodiments, the glass layer formed at the overlapping portion of the electrical coupling portion 4 and the collector grid line 5 is thicker, and the glass layer formed at the non-overlapping portion of the electrical coupling portion 4 and the collector grid line 5 is thinner. The thickness of the glass layer can be characterized by an 8-bit gray value, where 0 to 255 represents a continuous change from black to white. The larger the gray value, the greater the image brightness, indicating the thicker the glass layer. For example, the average gray value at the overlapping portion of the electrical coupling portion 4 in the N region and the collector grid line 5 is 5 to 15 higher than that at the non-overlapping portion, and the average gray value at the overlapping portion of the electrical coupling portion 4 in the P region and the collector grid line 5 is 15 to 50 higher than that at the non-overlapping portion, indicating that the glass layer at the overlapping portion of the electrical coupling portion 4 in the P region and the collector grid line 5 is thicker than that in the N region. Since both the electrical coupling portion paste and the collector grid line paste exist at the overlapping portion of the electrical coupling portion 4 and the collector grid line 5, the metal composition and the glass frit content are higher. Therefore, the glass layer in this region is thicker after sintering, and the number and density of the precipitated metal crystals are larger. And because the metal consumption in the P region is higher than that in the N region, the glass layer in the P region is thicker than that in the N region.

[0088] In some embodiments, the silicon substrate 1 can be made of materials such as N-type or P-type single crystal silicon, polycrystalline silicon, microcrystalline silicon, etc. The material of the doped semiconductor layer 2 can include doped polycrystalline silicon, doped microcrystalline silicon, doped nanocrystalline silicon, doped amorphous silicon, etc. The material of the passivation and antireflection layer 3 can include materials such as silicon oxide, silicon carbide, aluminum oxide, or titanium oxide. The passivation and antireflection layer can be a single layer or a stacked layer structure composed of one or more of the above materials. The materials and doping types of the silicon substrate 1 and the doped semiconductor layer 2 are reasonably selected according to the battery type. For example, when the doped semiconductor layer 2 is doped polycrystalline silicon, it can form a tunneling passivation contact structure with the tunneling oxide layer. When the doped semiconductor layer 2 is doped amorphous silicon, it can form a heterojunction contact structure with intrinsic amorphous silicon. The formed solar cell can be a back contact solar cell or a bifacial solar cell with a tunneling passivation contact structure and / or a heterojunction contact structure, which is not specifically limited herein.

[0089] In some embodiments, the doped semiconductor layer 2 forms a tunneling passivation contact structure composed of doped polysilicon and a tunneling oxide layer, and the tunneling oxide layer is located between the silicon substrate 1 and the doped semiconductor layer 2. The tunneling oxide layer can prevent metal crystals from piercing through the doped semiconductor layer into the silicon substrate 1, avoiding the damage of the passivation on the surface of the solar cell and thus losing the cell efficiency. The materials of the dielectric layer include materials such as silicon oxide and titanium oxide.

[0090] Based on the solar cell described in any of the above embodiments, an embodiment of the present invention further provides a photovoltaic module. The photovoltaic module includes a plurality of cell strings. Each cell string includes the solar cell described in any of the above embodiments and electrical connection lines. The electrical connection lines are disposed on the electrical bonding portion 4 and at least cover a part of the electrical bonding portion 4; the electrical connection lines are electrically connected to the electrical bonding portion 4 through a bonding material. Among them, the electrical connection lines are conductive interconnecting members and can be wires such as solder tapes that can achieve conductive connection.

[0091] In the case of adopting the above technical solution, each solar cell of the cell string is connected in series through the connection between the electrical connection line and the electrical bonding portion 4. Since the photovoltaic module adopts the solar cell described in any of the above embodiments, the photovoltaic module has the same beneficial effects as any of the above embodiments. On the one hand, setting metal crystals in the electrode overlapping region 101 of the passivation and antireflection layer 3 will expand the contact area between the collector grid line 5 and the doped semiconductor layer 2, improving the efficiency of the collector grid line 5 in collecting current; on the other hand, forming metal crystals in the passivation and antireflection layer 3 under the electrical bonding portion 4 can improve the bonding force between the electrode and the doped semiconductor layer 2, improving the electrode connection tensile force, and further improving the reliability of the electrode connection. In addition, during the end string soldering of the module, since the collector grid line 5 covers a part of the surface of the electrical bonding portion 4 away from the silicon substrate 1, the electrical connection line can be directly connected to the collector grid line 5. Compared with the traditional conductive structure "collector grid line - pad - electrical connection line", it reduces the intermediate conductive process through the electrical bonding portion, reduces the current loss, and can effectively improve the module power.

[0092] In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0093] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A solar cell, characterized in that: include: a silicon substrate having two opposing sides; A doped semiconductor layer is disposed on at least one side of the silicon substrate; A passivation anti-reflection layer, arranged on a surface of the doped semiconductor layer away from the silicon substrate, the passivation anti-reflection layer comprising an electrode overlapping region and a non-electrode overlapping region; An electrical bonding portion is arranged on a surface of the passivation anti-reflection layer away from the silicon substrate; A collector grid line, part of which covers a portion of the surface of the electrical junction away from the silicon substrate; The electrode overlapping region corresponds to the overlapping portion of the electrical combination and the collector grid line, the non-electrode overlapping region corresponds to the non-overlapping portion of the electrical combination and the collector grid line, and metal crystals exist in the electrode overlapping region.

2. The solar cell according to claim 1, characterized in that The number of metal crystals in the electrode overlapping region is greater than the number of metal crystals in the electrode non-overlapping region.

3. The solar cell according to claim 2, characterized in that: The orthographic projection area of ​​the metal crystals in the electrode overlapping region on the electrode overlapping region accounts for 10% to 60% of the area of ​​the electrode overlapping region; And / or, the orthographic projection area of ​​the metal crystals in the non-electrode overlapping region on the non-electrode overlapping region accounts for 0% to 10% of the area of ​​the non-electrode overlapping region.

4. The solar cell according to claim 1, characterized in that The doped semiconductor layer comprises a first doped semiconductor layer and a second doped semiconductor layer, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types; The passivation anti-reflection layer comprises a first passivation anti-reflection layer located on the first doped semiconductor layer and a second passivation anti-reflection layer located on the second doped semiconductor layer, and the first passivation anti-reflection layer and the second passivation anti-reflection layer both comprise the electrode overlapping region and the non-electrode overlapping region; The number of metal crystals in the electrode overlapping region of the first passivation anti-reflection layer is greater than the number of metal crystals in the electrode overlapping region of the second passivation anti-reflection layer.

5. The solar cell according to claim 1, characterized in that: The number of metal crystals in the electrode overlapping region is less than the number of metal crystals in the portion of the passivation anti-reflection layer that overlaps with the collector grid line and excludes the electrode overlapping region.

6. The solar cell according to claim 1, characterized in that The electrical connection part is intermittently arranged along a direction perpendicular to the extending direction of the collector grid line.

7. The solar cell according to claim 1, characterized in that The height of the electrical combination portion on the electrode overlapping region is smaller than the height of the electrical combination portion on the electrode non-overlapping region.

8. The solar cell according to claim 1, characterized in that The surface of the electrode overlap region has a corrosion area; The doped semiconductor layer comprises a first doped semiconductor layer and a second doped semiconductor layer, and the first doped semiconductor layer and the second doped semiconductor layer have opposite conductivity types; The passivation anti-reflection layer comprises a first passivation anti-reflection layer located on the first doped semiconductor layer and a second passivation anti-reflection layer located on the second doped semiconductor layer, and the first passivation anti-reflection layer and the second passivation anti-reflection layer both comprise the electrode overlapping region and the non-electrode overlapping region; The ratio of the corrosion area of ​​the first passivation anti-reflection layer to the area corresponding to the electrode overlap area is greater than the ratio of the corrosion area of ​​the second passivation anti-reflection layer to the area corresponding to the electrode overlap area.

9. The solar cell according to claim 8, characterized in that The area of ​​the corrosion area of ​​the first passivation anti-reflection layer accounts for 80% to 100%; And / or, the area proportion of the corrosion zone of the second passivation anti-reflection layer is 10% to 70%.

10. The solar cell according to claim 8, characterized in that The corrosion area has a contact hole penetrating the passivation anti-reflection layer, and the metal crystal in the contact hole is in contact with the doped semiconductor layer and / or the collector grid line.

11. The solar cell according to claim 1, characterized in that: The surface of the non-electrode overlapping region away from the silicon substrate has a blind hole that does not penetrate the passivation anti-reflection layer; Alternatively, a surface of the non-electrode overlapping region away from the silicon substrate has a blind hole that does not penetrate the passivation anti-reflection layer, and the blind hole contains metal crystals.

12. A photovoltaic module, characterized in that: The photovoltaic assembly comprises a plurality of battery strings, wherein the battery strings comprise the solar cell and the electrical connection wire electrical connection portion according to any one of claims 1 to 11, wherein the electrical connection wire is arranged on the electrical connection portion, and the electrical connection wire at least covers a portion of the electrical connection portion; The electrical connection line is electrically connected to the electrical connection portion through a bonding material.

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