Solar cell, cell assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a solar cell, a cell assembly and a photovoltaic system, and the solar cell comprises a silicon substrate which comprises at least one N region and at least one P region; the N-type doped polycrystalline silicon layer is arranged on the N region; the P-type doped polycrystalline silicon layer is arranged on the P region; the first passivation layer is located in the N region, and a first notch is formed in the first passivation layer in a penetrating manner; the second passivation layer is located in the P region, and a second notch is formed in the second passivation layer in a penetrating manner; the first electrode is arranged in the N region and penetrates through the first notch to be in contact with the N-type doped polycrystalline silicon layer; the second electrode is arranged in the P region and penetrates through the second notch to be in contact with the P-type doped polycrystalline silicon layer; and the width of at least partial area of the at least one second notch is greater than the maximum width of the at least one first notch. According to the solar cell, the contact area of the second electrode and the P-type doped polycrystalline silicon layer can be increased, the conversion efficiency of the cell is improved, and the structural reliability of the cell is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of solar cells, in particular to a solar cell, a battery assembly and a photovoltaic system. Background Art

[0002] Solar cells can convert sunlight into electrical energy by using the photovoltaic effect of semiconductors. Solar cells mainly include bifacial solar cells and back-contact solar cells. Among them, the back-contact solar cell has both positive and negative electrodes designed on the back of the cell. Compared with bifacial solar cells, the front surface of the back-contact solar cell completely avoids the shading of metal grid lines, eliminating the optical loss caused by the shading of metal grid lines, which can greatly improve the cell conversion efficiency.

[0003] In the prior art, an N-type doped polysilicon layer is disposed on one side of the silicon substrate of a bifacial solar cell, and a P-type doped polysilicon layer is disposed on the other side of the silicon substrate. The first electrode of the bifacial solar cell contacts the N-type doped polysilicon layer, and the second electrode of the bifacial solar cell contacts the P-type doped polysilicon layer; an N-type doped polysilicon layer and a P-type doped polysilicon layer are alternately disposed on the back side of the silicon substrate of a back contact solar cell, and the first electrode of the back contact solar cell contacts the N-type doped polysilicon layer, and the second electrode of the back contact solar cell contacts the P-type doped polysilicon layer. Since conventional solar cells generally do not consider the relationship between the contact area between the first electrode and the N-type doped polysilicon layer and the contact area between the second P electrode and the P-type doped polysilicon layer, the contact effect between the P-type doped polysilicon layer and the second electrode is relatively poor compared to the contact effect between the N-type doped polysilicon layer and the first electrode, resulting in poor conductivity in the P region, affecting the battery efficiency, and the bonding tension between the P-type doped polysilicon layer and the electrode is small, and the battery structure has poor reliability. Utility Model Content

[0004] The utility model provides a solar cell, aiming to solve the problem that the contact area between the P-type doped polysilicon layer and the electrode of the solar cell in the prior art is small, resulting in poor conductivity of the P region, affecting the battery efficiency, and poor reliability of the battery structure.

[0005] The utility model is implemented by providing a solar cell, comprising:

[0006] A silicon substrate, wherein the silicon substrate comprises at least one N region and at least one P region, wherein the N region and the P region are located on the same surface of the silicon substrate, or the N region and the P region are located on two opposite surfaces of the silicon substrate;

[0007] An N-type doped polysilicon layer is disposed on the N region;

[0008] A P-type doped polysilicon layer is disposed on the P region;

[0009] A first passivation layer located in the N region is provided on a side of the N-type doped polysilicon layer away from the silicon substrate, and a first notch is provided through the first passivation layer along a thickness direction thereof;

[0010] A second passivation layer located in the P region is provided on a side of the P-type doped polysilicon layer away from the silicon substrate, and a second notch is provided through the second passivation layer along the thickness direction thereof;

[0011] a first electrode disposed in the N region, the first electrode passing through the first notch and contacting the N-type doped polysilicon layer;

[0012] a second electrode disposed in the P region, the second electrode passing through the second notch and contacting the P-type doped polysilicon layer;

[0013] Wherein, the width of at least a partial area of ​​at least one of the second notches is greater than the maximum width of at least one of the first notches.

[0014] Preferably, the width of all regions of at least one of the second notches is greater than the maximum width of at least one of the first notches.

[0015] Preferably, the width of all regions of any one of the second notches is greater than the maximum width of any one of the first notches.

[0016] Preferably, the second notch includes a first area corresponding to a welding position of the second electrode and a second area corresponding to a non-welding position of the second electrode, and a width of the first area of ​​the second notch is greater than a maximum width of the first notch.

[0017] Preferably, the width of the first region is greater than or equal to the width of the second region.

[0018] Preferably, the first notch includes a third area corresponding to the welding position of the first electrode and a fourth area corresponding to the non-welding position of the first electrode, and a width of the first area of ​​the second notch is greater than a width of the third area of ​​the first notch.

[0019] Preferably, a width of the second region of the second notch is greater than a width of the fourth region of the first notch.

[0020] Preferably, the area of ​​any one of the second notches is larger than the area of ​​any one of the first notches.

[0021] Preferably, a ratio of a contact area between the second electrode and the P-type doped polysilicon layer to a contact area between the first electrode and the N-type doped polysilicon layer is 1 to 1.5, and is not equal to 1.

[0022] Preferably, the ratio of the contact area between the second electrode and the P-type doped polysilicon layer to the contact area between the first electrode and the N-type doped polysilicon layer is 1.01-1.2.

[0023] Preferably, widths of the first notches in at least two of the N regions are unequal.

[0024] Preferably, the widths of the second notches in at least two of the P regions are unequal.

[0025] Preferably, a plurality of first countersunk holes are provided in a region of the N-type doped polysilicon layer corresponding to the first notch, and the first electrode passes through the first notch and contacts with each of the first countersunk holes;

[0026] A plurality of second countersunk holes are arranged in the area of ​​the P-type doped polysilicon layer corresponding to the second notch, the second electrode passes through the second notch and contacts each of the second countersunk holes, and the number of the second countersunk holes corresponding to each of the second notches is greater than the number of the first countersunk holes corresponding to each of the first notches.

[0027] Preferably, the aperture of the second countersunk hole is larger than the aperture of the first countersunk hole.

[0028] Preferably, the distribution density of the second countersunk holes is greater than the distribution density of the first countersunk holes.

[0029] Preferably, the depth of the second countersunk hole is greater than the depth of the first countersunk hole.

[0030] Preferably, a depth at which the second electrode enters the P-type doped polysilicon layer is greater than a depth at which the first electrode enters the N-type doped polysilicon layer.

[0031] Preferably, the ratio of the depth of the second electrode penetrating into the P-type doped polysilicon layer to the depth of the first electrode penetrating into the N-type doped polysilicon layer is 1.01-2.

[0032] Preferably, the solar cell is a back-contact solar cell, and the N region and the P region are located on the same surface of the silicon substrate.

[0033] Preferably, the solar cell is a double-sided solar cell, and the N region and the P region are respectively located on two opposite sides of the silicon substrate.

[0034] The utility model also provides a battery assembly, comprising the above-mentioned solar cell.

[0035] The utility model also provides a photovoltaic system, comprising the above-mentioned battery assembly.

[0036] The utility model provides a solar cell with at least one N region and at least one P region, wherein an N-type doped polysilicon layer is arranged in the N region, and a P-type doped polysilicon layer is arranged in the P region, a first notch is arranged in a first passivation layer on a side of the N-type doped polysilicon layer away from a silicon substrate, and a second notch is arranged in a second passivation layer on a side of the P-type doped polysilicon layer away from the silicon substrate, a first electrode passes through the first notch to contact the N-type doped polysilicon layer, and a second electrode passes through the second notch to contact the P-type doped polysilicon layer, and the width of at least a part of the at least one second notch can be increased, so that the width of at least a part of the at least one second notch is greater than the maximum width of the at least one first notch, and the contact area between at least a part of the second electrode and the P-type doped polysilicon layer can be increased, so that the second electrode and the P-type doped polysilicon layer form a good ohmic contact, and the conductive effect of the P region can be improved, thereby improving the conversion efficiency of the battery; and, because the contact area between the second electrode and the P-type doped polysilicon layer is increased, the bonding tension between the second electrode and the P-type doped polysilicon layer can be increased, and the reliability of the battery structure can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A cross-sectional schematic diagram of a solar cell provided in Embodiment 1 of the utility model;

[0038] Figure 2 A schematic cross-sectional view of a solar cell provided in Embodiment 1 of the utility model after removing the first electrode and the second electrode;

[0039] Figure 3 A schematic diagram of the back side of a solar cell provided in the first embodiment of the utility model;

[0040] Figure 4 A schematic diagram of the back side of another solar cell provided in the first embodiment of the utility model;

[0041] Figure 5 A schematic diagram of a second notch and a second countersunk hole of a solar cell provided in Embodiment 1 of the utility model;

[0042] Figure 6 A schematic diagram of a first notch and a first countersunk hole of a solar cell provided in Embodiment 1 of the utility model;

[0043] Figure 7 A cross-sectional schematic diagram of a solar cell provided in Embodiment 2 of the present utility model;

[0044] Figure 8 A front view schematic diagram of a solar cell provided in the second embodiment of the utility model;

[0045] Fig. 9 This is a schematic diagram of the back side of a solar cell provided in Embodiment 2 of the present utility model. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0047] A solar cell provided by an embodiment of the utility model is provided with at least one N region and at least one P region, an N-type doped polysilicon layer is provided in the N region, a P-type doped polysilicon layer is provided in the P region, a first notch is provided in a first passivation layer on a side of the N-type doped polysilicon layer facing away from a silicon substrate, and a second notch is provided in a second passivation layer on a side of the P-type doped polysilicon layer facing away from the silicon substrate, a first electrode passes through the first notch to contact the N-type doped polysilicon layer, and a second electrode passes through the second notch to contact the P-type doped polysilicon layer, so that the width of at least a part of the at least one second notch can be increased, so that the width of at least a part of the at least one second notch is greater than the maximum width of the at least one first notch, so that the contact area between at least a part of the second electrode and the P-type doped polysilicon layer can be increased, so that the second electrode and the P-type doped polysilicon layer form a good ohmic contact, and the conductive effect of the P region can be improved, thereby improving the conversion efficiency of the battery; and, since the contact area between the second electrode and the P-type doped polysilicon layer is increased, the bonding tension between the second electrode and the P-type doped polysilicon layer can be increased, thereby improving the reliability of the battery structure.

[0048] Embodiment 1

[0049] Please refer to Figure 1-Figure 4 , a solar cell provided by an embodiment of the utility model comprises:

[0050] A silicon substrate 1, wherein the silicon substrate 1 comprises at least one N region 11 and at least one P region 12, wherein the N region 11 and the P region 12 are located on the same surface of the silicon substrate 1;

[0051] An N-type doped polysilicon layer 2 is disposed on the N region 11;

[0052] A P-type doped polysilicon layer 3 is disposed on the P region 12;

[0053] The first passivation layer 4 located in the N region 11 is provided on a side of the N-type doped polysilicon layer 2 away from the silicon substrate 1, and a first notch 41 is provided through the first passivation layer 4 along the thickness direction thereof;

[0054] The second passivation layer 5 located in the P region 12 is disposed on the side of the P-type doped polysilicon layer 3 away from the silicon substrate 1, and the second passivation layer 5 is penetrated by a second notch 51 along the thickness direction thereof;

[0055] A first electrode 6 disposed in the N region 11 , the first electrode 6 passes through the first notch 41 and contacts the N-type doped polysilicon layer 2 ;

[0056] A second electrode 7 disposed in the P region 12 , the second electrode 7 passes through the second notch 51 and contacts the P-type doped polysilicon layer 3 ;

[0057] The width of at least a partial area of ​​the at least one second notch 51 is greater than the maximum width of the at least one first notch 41 .

[0058] In the embodiment of the present invention, the width direction of the second notch 51 and the width direction of the first notch 41 are both along Figure 3 and Figure 4 In the X direction, the length direction of the second slot 51 and the length direction of the first slot 41 are both along Figure 3 and Figure 4 The maximum width of the first notch 41 is the maximum dimension of the first notch 41 along the X direction.

[0059] In the embodiment of the utility model, the first notch 41 and the second notch 51 can be formed by laser grooving or prepared by other processes. The shapes of the first notch 41 and the second notch 51 can be the same or different. The first notch 41 and the second notch 51 can be square grooves, oval grooves or irregular shapes. Figure 3 The shapes of the first notch 41 and the second notch 51 shown in the figure are both irregular, and the widths of the first notch 41 and the second notch 51 are not equal along their length directions; Figure 4 The shapes of the first notch 41 and the second notch 51 shown in the figure are both square notches, and the widths of the first notch 41 and the second notch 51 are kept equal along their length directions.

[0060] In the embodiment of the utility model, the solar cell is a back contact solar cell, the silicon substrate 1 includes a first surface and a second surface opposite to the first surface, one of the first surface and the second surface is a light-facing surface 101, and the other is a backlight surface 102. In this embodiment, the N region 11 and the P region 12 are both located on the backlight surface 102.

[0061] In the embodiment of the utility model, there are multiple N regions 11 and P regions 12. In the embodiment, the N regions 11 and P regions 12 are alternately arranged on the backlight surface 102, and an isolation region 13 for isolating the N region 11 and the P region 12 is arranged between adjacent N regions 11 and P regions 12. Specifically, the isolation region 13 can be a groove.

[0062] A solar cell provided by an embodiment of the utility model is provided with a first notch 41 on a first passivation layer 4 on a side of an N-type doped polysilicon layer 2 facing away from a silicon substrate 1, and a second notch 51 is provided on a second passivation layer 5 on a side of a P-type doped polysilicon layer 3 facing away from the silicon substrate 1, a first electrode 6 passes through the first notch 41 to contact the N-type doped polysilicon layer 2, and a second electrode 7 passes through the second notch 51 to contact the P-type doped polysilicon layer 3. By increasing the width of at least a partial area of ​​at least one second notch 51, the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 can be increased, and the second electrode 7 corresponding to the widened area of ​​the second notch 51 can be in contact with the P-type doped polysilicon layer 3 for conductivity through the second notch 51 with a larger area, so that the second electrode 7 and the P-type doped polysilicon layer 3 form a better ohmic contact, thereby improving the conductive effect of the second electrode 7 and the P-type doped polysilicon layer 3, balancing the conductive effects of the N region and the P region, and improving the conversion efficiency of the solar cell; moreover, compared with the contact area between the first electrode 6 and the N-type doped polysilicon layer 2, the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 is increased, thereby increasing the bonding tension between the P-type doped polysilicon layer 3 and the second electrode 7, and the connection between the second electrode 7 and the P-type doped polysilicon layer 3 is more stable and reliable, which can improve the reliability of the battery structure.

[0063] In the embodiment of the utility model, the width of at least a partial area of ​​at least one second notch 51 is greater than the maximum width of at least one first notch 41. It can be understood that the width of a partial area of ​​at least one second notch 51 is greater than the maximum width of at least one first notch 41 or the width of all areas of at least one second notch 51 is greater than the maximum width of at least one first notch 41. It is sufficient that at least a partial area of ​​a second notch 51 has a width greater than the maximum width of a first notch 41. The width of at least a certain area of ​​the second notch 51 can be increased, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 in certain areas (such as the solder joint area), increasing the width of the second electrode 7 and the solder strip soldering area or increasing the width of the entire second electrode 7, and improving the conductive effect and bonding tension of the soldering area of ​​the second electrode 7 or the entire second electrode 7 and the P-type doped polysilicon layer 3.

[0064] In the embodiment of the utility model, the first electrode 6 and the second electrode 7 can be prepared by screen printing or electroplating process, the slurry of the first electrode 6 is filled into the first notch 41 and contacts the N-type doped polysilicon layer 2, and the slurry of the second electrode 7 is filled into the second notch 51 and contacts the P-type doped polysilicon layer 3. Since the width of the second notch 51 in a certain area is at least increased, the second electrode 7 corresponding to the widened second notch 51 can have more slurry contacting the P-type doped polysilicon layer 3 through the second notch 51, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0065] As an embodiment of the present invention, the width of all regions of the at least one second notch 51 is greater than the maximum width of the at least one first notch 41 .

[0066] In this embodiment, the width of all areas of at least one second notch 51 is greater than the maximum width of at least one first notch 41, that is, compared with the first notch 41, all areas of at least one second notch 51 are widened, thereby further improving the contact area between the second electrode 7 corresponding to the second notch 51 and the P-type doped polysilicon layer 3, and further improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0067] In practical applications, the width of all areas of one of the second notches 51 may be greater than the maximum width of at least one first notch 41, or the width of all areas of two of the second notches 51 may be greater than the maximum width of at least one first notch 41, or the width of all areas of all the second notches 51 may be greater than the maximum width of at least one first notch 41.

[0068] As a preferred embodiment of the present invention, the width of all regions of any second notch 51 is greater than the maximum width of any first notch 41 .

[0069] In this embodiment, the width of all areas of each second notch 51 is greater than the maximum width of each first notch 41. Compared with the first notch 41, the width of all areas of each second notch 51 is widened, which can increase the contact area between each second electrode 7 and the P-type doped polysilicon layer 3, and further improve the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0070] As an embodiment of the present invention, the second notch 51 includes a first area 511 corresponding to the welding position of the second electrode 7 and a second area 512 corresponding to the non-welding position of the second electrode 7 along its length direction, and the width d1 of the first area 511 of the second notch 51 is greater than the maximum width of the first notch 41.

[0071] In this embodiment, the first area 511 of the second notch 51 corresponds to the area corresponding to the welding position of the second electrode 7; the second area 512 of the second notch 51 corresponds to the area corresponding to the non-welding position of the second electrode 7. The first area 511 and the second area 512 are alternately arranged in sequence along the length direction of the second notch 51 and are connected to each other. Figure 3 Three are shown in FIG.

[0072] Since the width of the first area 511 of the second notch 51 is set to be greater than the maximum width of the first notch 41, when the second electrode 7 is screen-printed, the width of the second electrode 7 corresponding to the second notch 51 can be made greater than the maximum width of the first notch 41, that is, the width of the welding area of ​​the second electrode 7 is widened, thereby improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3, and increasing the welding contact area between the second electrode 7 and the welding strip, thereby improving the welding effect.

[0073] As an embodiment of the present invention, the width of the first region 511 is greater than or equal to the width d3 of the second region 512 .

[0074] In this embodiment, the width d1 of the first region 511 can be greater than the width d3 of the second region 512, and the width d1 of the first region 511 is greater than the maximum width of the first notch 41, so that the width of the second electrode 7 at the welding position is greater than the width of the non-welding position, which can improve the welding effect between the second electrode 7 and the welding strip; and because the width of the first region 511 is greater than the maximum width of the first notch 41, the width of the welding position and the width of the non-welding position of the second electrode 7 are both greater than the maximum width of the first notch 41, that is, the width of the welding position and the width of the non-welding position of the second electrode 7 are both widened, which is conducive to increasing the contact area between the entire second electrode 7 and the P-type doped polysilicon layer 3. In addition, the width of the first region 511 can also be equal to the width of the second region 512, which is convenient for the processing of the second notch 51, and compared with the first notch 41, the width of the first region 511 and the width of the second region 512 are also widened, that is, all regions of the second electrode 7 are widened, which can improve the contact area between the entire second electrode 7 and the P-type doped polysilicon layer 3.

[0075] As an embodiment of the present invention, the first notch 41 includes a third area 411 corresponding to the welding position of the first electrode 6, and a fourth area 412 corresponding to the non-welding position of the first electrode 6, and the width d1 of the first area 511 of the second notch 51 is greater than the width d2 of the third area 411 of the first notch 41.

[0076] In this embodiment, the third area 411 of the first notch 41 corresponds to the area corresponding to the welding position of the first electrode 6; the fourth area 412 of the first notch 41 corresponds to the area corresponding to the non-welding position of the first electrode 6. The third area 411 and the fourth area 412 are alternately arranged in sequence along the length direction of the first notch 41 and are connected to each other. Figure 3 Three are shown in FIG. 4 , and the width d2 of the third area 411 of the first notch 41 is the maximum width of the first notch 41 .

[0077] Among them, since the width d1 of the first area 511 of the second notch 51 is greater than the width d2 of the third area 411 of the first notch 41, the width of the second electrode 7 corresponding to the first area 511 is greater than the width of the first electrode 6 corresponding to the third area 411, that is, the width of the welding area of ​​the second electrode 7 is greater than the width of the welding area of ​​the first electrode 6, which can improve the conductive effect and bonding tension between the welding area of ​​the second electrode 7 and the P-type doped polysilicon layer 3, and increase the welding contact area between the welding area of ​​the second electrode 7 and the welding strip, thereby improving the welding effect.

[0078] As an embodiment of the present invention, a width d3 of the second area 512 of the second notch 51 is greater than a width d4 of the fourth area 412 of the first notch 41 .

[0079] In this embodiment, the width d3 of the second area 512 of the second notch 51 is greater than the width d4 of the fourth area 412 of the first notch 41, so the width of the second electrode 7 corresponding to the second area 512 is greater than the width of the first electrode 6 corresponding to the fourth area 412, that is, the width of the non-welding area of ​​the second electrode 7 is greater than the width of the non-welding area of ​​the first electrode 6, which can further enhance the conductive effect and bonding tension between the non-welding area of ​​the second electrode 7 and the P-type doped polysilicon layer 3.

[0080] As an embodiment of the present invention, a width d4 of the fourth area 412 of the first notch 41 is greater than a width d2 of the third area 411 of the first notch 41 .

[0081] As an embodiment of the present invention, the area of ​​any second notch 51 is greater than the area of ​​any first notch 41. In the embodiment of the present invention, the area of ​​the first notch 41 is the area of ​​the cross section of the first notch 41; the area of ​​the second notch 51 is the area of ​​the cross section of the second notch 51. For example, Figure 3 When the first notch 41 and the second notch 51 are both square notches, the cross-section of the first notch 41 and the cross-section of the second notch 51 are also square notches.

[0082] In this embodiment, the area of ​​the second notch 51 of each P region 12 is larger than the area of ​​the first notch 41 of each N region 11, so that the area of ​​each second notch 51 is enlarged, which can increase the contact area between each second electrode 7 and the P-type doped polysilicon layer 3, thereby improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0083] As an embodiment of the present invention, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is 1-1.5 and is not equal to 1.

[0084] Among them, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 can be: 1.01, or 1.05, or 1.1, or 1.15, or 1.2, or 1.23, or 1.28, or 1.3, or 1.35, or 1.38, or 1.4, or 1.42, or 1.47, or 1.5.

[0085] In this embodiment, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is set to 1 to 1.5, and is not equal to 1. That is, the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 and the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 can have a relatively suitable difference, and it is convenient to set the first notch 41 and the second notch 51.

[0086] As an embodiment of the utility model, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is 1.01 to 1.2, which can further reduce the difference between the area of ​​the P-type doped polysilicon layer 3 and the area of ​​the N-type doped polysilicon layer 2, which is conducive to making the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 and the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 have a more appropriate difference.

[0087] As an embodiment of the present invention, the widths of the first notches 41 of at least two N regions 11 are unequal.

[0088] In this embodiment, the widths of the first notches 41 of at least two N regions 11 are not equal. It can be understood that, among the multiple N regions 11, the width of the first notch 41 of at least one N region 11 is not equal to the width of the first notch 41 of at least one N region 11 in the other N regions 11. In this way, the width of the first electrode 6 can be changed by adjusting the width of the first notch 41 corresponding to at least one of the N regions 11, so that the width of at least one first electrode 6 is different from the width of other first electrodes 6, and the differentiated design of the width of the first electrode 6 can be realized, which can improve the light absorption range and photoelectric conversion efficiency of the solar cell and maximize the use of light energy resources.

[0089] As an embodiment of the present invention, the widths of the second notches 51 of at least two P regions 12 are unequal.

[0090] In this embodiment, the width of the second notch 51 of at least one P region 12 is not equal to the width of the second notch 51 of at least one P region 12. It can be understood that, among the multiple P regions 12, the width of the second notch 51 of at least one P region 12 is not equal to the width of the second notch 51 of at least one P region 12 in the other P regions 12. The width of the second electrode 7 can be changed by adjusting the width of the second notch 51 corresponding to at least one of the P regions 12, so that the width of at least one second electrode 7 can be different from the width of other second electrodes 7, and the differentiated width design of the second electrode 7 can be realized, which can further improve the light absorption range and photoelectric conversion efficiency of the solar cell and maximize the use of light energy resources.

[0091] As an embodiment of the utility model, a plurality of first countersunk holes 21 are arranged in an area of ​​the N-type doped polysilicon layer 2 corresponding to a first notch 41, and the first electrode 6 passes through the first notch 41 to contact each first countersunk hole; a plurality of second countersunk holes 31 are arranged in an area of ​​the P-type doped polysilicon layer 3 corresponding to a second notch 51, and the second electrode 7 passes through the second notch 51 to contact each second countersunk hole, and the number of second countersunk holes 31 corresponding to each second notch 51 is greater than the number of first countersunk holes 21 corresponding to a first notch 41.

[0092] In this embodiment, by setting a plurality of first countersunk holes 21 in the region of the N-type doped polysilicon layer 2 corresponding to the first notch 41, and setting a plurality of second countersunk holes 31 in the region of the P-type doped polysilicon layer 3 corresponding to a second notch 51, the first electrode 6 enters the first notch 41 and can enter the first countersunk hole 21 to contact the first countersunk hole 21, which can improve the contact effect between the first electrode 6 and the N-type doped polysilicon layer 2, and the second electrode 7 enters the second notch 51 and can enter the second countersunk hole 31 to contact the second countersunk hole 31, which can improve the contact effect between the second electrode 7 and the P-type doped polysilicon layer 3; and, since the number of second countersunk holes 31 corresponding to one second notch 51 is greater than the number of first countersunk holes 21 corresponding to one first notch 41, the second electrode 7 can contact with a larger number of second countersunk holes 31, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3. Wherein, the first countersunk hole 21 and the second countersunk hole 31 can both be circular countersunk holes.

[0093] As an embodiment of the present invention, the diameter of the second counterbore 31 is larger than the diameter of the first counterbore 21 .

[0094] In this embodiment, since the aperture of the second countersunk hole 31 is larger than the aperture of the first countersunk hole 21 , the area of ​​each second countersunk hole 31 is larger than the area of ​​each first countersunk hole 21 , which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 .

[0095] As an embodiment of the present invention, the distribution density of the second countersunk holes 31 is greater than the distribution density of the first countersunk holes 21 .

[0096] In this embodiment, the distribution density of the second countersunk holes 31 is greater than the distribution density of the first countersunk holes 21. It can be understood that, within a unit area, the number of second countersunk holes 31 is greater than the number of first countersunk holes 21, so that the second electrode 7 can contact with more areas of the second countersunk holes 31, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0097] As an embodiment of the present invention, the depth of the second counterbore 31 is greater than the depth of the first counterbore 21 .

[0098] In this embodiment, since the depth of the second countersunk hole 31 is greater than the depth of the first countersunk hole 21, the second electrode 7 can enter the deeper second countersunk hole 31, thereby making the second electrode 7 have more contact area with the P-type doped polysilicon layer 3, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0099] As an embodiment of the present invention, the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2 .

[0100] In this embodiment, after the slurry of the second electrode 7 passes through the second groove 51, the slurry of the second electrode 7 can enter the P-type doped polysilicon layer 3, and after the slurry of the first electrode 6 passes through the first groove 41, the slurry of the first electrode 6 can enter the N-type doped polysilicon layer 2, and the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2, which can also increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0101] Among them, when the first electrode 6 and the second electrode 7 are prepared by the screen printing process, the slurry ratio of the second electrode 7 and the first electrode 6 can be adjusted so that the slurries of the second electrode 7 and the first electrode 6 have different burn-through capabilities, so that the burn-through capability of the slurry of the second electrode 7 is greater than the burn-through capability of the slurry of the first electrode 6, so that the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0102] As an embodiment of the present invention, the ratio of the depth of the second electrode 7 penetrating into the P-type doped polysilicon layer 3 to the depth of the first electrode 6 penetrating into the N-type doped polysilicon layer 2 is 1.01-2.

[0103] In this embodiment, the ratio of the depth of the second electrode 7 penetrating into the P-type doped polysilicon layer 3 to the depth of the first electrode 6 penetrating into the N-type doped polysilicon layer 2 may be 1.01, or 1.20, or 1.35, or 1.55, or 1.60, or 1.80, or 1.90, or 2.0.

[0104] As an embodiment of the present invention, the solar cell includes multiple first electrodes 6 and multiple second electrodes 7 , at least one second electrode 7 has a width greater than that of at least one first electrode 6 , and at least one second electrode 7 has a width less than that of at least one first electrode 6 .

[0105] In this embodiment, a plurality of first electrodes 6 are respectively arranged in the N region 11, and a plurality of second electrodes 7 are respectively arranged in the P region 12. Among them, the width of at least one second electrode 7 is greater than the width of at least one first electrode 6, and the width of at least one second electrode 7 is less than the width of at least one first electrode 6, so that the width of the second electrode 7 is not consistent with the width of the first electrode 6, and the width difference between the first electrode 6 and the second electrode 7 can be flexibly adjusted instead of setting an electrode with a single width, which can improve the light absorption range and photoelectric conversion efficiency of the solar cell, and maximize the use of light energy resources, and greatly increase the probability of collecting photocurrent without affecting the production capacity.

[0106] In this embodiment, the width of the first electrode 6 can be adjusted by adjusting the width of the first notch 41 corresponding to each first electrode 6, and the width of the second electrode 7 can be adjusted by adjusting the width of the second notch 51 corresponding to each second electrode 7. This can achieve an optimized design of the widths of the first electrode 6 and the second electrode 7, thereby improving battery efficiency.

[0107] As an embodiment of the utility model, the first passivation layer 4 and the second passivation layer 5 are both at least one or a combination of aluminum oxide film layers, silicon oxide film layers, silicon nitride film layers, silicon carbide film layers, and silicon oxynitride film layers. For example, in some embodiments, the first passivation layer 4 and the second passivation layer 5 can both include aluminum oxide film layers and silicon nitride film layers stacked in sequence.

[0108] Please refer to Figure 1 and Figure 2 As an embodiment of the utility model, the solar cell further includes a first tunneling layer 8 disposed between the N-type doped polysilicon layer 2 and the surface of the silicon substrate 1, and a second tunneling layer 9 disposed between the P-type doped polysilicon layer 3 and the surface of the silicon substrate 1.

[0109] In this embodiment, the first tunneling layer 8 and the second tunneling layer 9 may be silicon oxide layers. The cell efficiency of the solar cell may be further improved by utilizing the tunneling passivation effect of the first tunneling layer 8 and the second tunneling layer 9 .

[0110] Embodiment 2

[0111] Please refer to Figure 7-Figure 9 , a solar cell provided by an embodiment of the utility model comprises:

[0112] A silicon substrate 1, wherein the silicon substrate 1 comprises at least one N region 11 and at least one P region 12, wherein the N region 11 and the P region 12 are respectively located on two opposite sides of the silicon substrate 1;

[0113] An N-type doped polysilicon layer 2 is disposed on the N region 11;

[0114] A P-type doped polysilicon layer 3 is disposed on the P region 12;

[0115] A first passivation layer 4 is provided on a side of the N-type doped polysilicon layer 2 facing away from the silicon substrate 1, and a first notch 41 is provided through the first passivation layer 4 along the thickness direction thereof;

[0116] A second passivation layer 5 is provided on a side of the P-type doped polysilicon layer 3 facing away from the silicon substrate 1, and a second notch 51 is provided through the second passivation layer 5 along the thickness direction thereof;

[0117] A first electrode 6 is disposed on the first passivation layer 4, and the first electrode 6 passes through a plurality of first notches 41 and contacts the N-type doped polysilicon layer 2;

[0118] A second electrode 7 is disposed on the second passivation layer 5, and the second electrode 7 passes through a plurality of second notches 51 and contacts the P-type doped polysilicon layer 3;

[0119] The width of at least a partial area of ​​the at least one second notch 51 is greater than the maximum width of the at least one first notch 41 .

[0120] The difference between the solar cell of this embodiment and the first embodiment is that the solar cell of this embodiment is a double-sided solar cell, the N region 11 and the P region 12 are respectively located on two opposite sides of the silicon substrate 1, and the other structures are the same as those of the first embodiment.

[0121] In the embodiment of the utility model, the solar cell is a back contact solar cell, and the silicon substrate 1 includes a first surface and a second surface opposite to the first surface, one of the first surface and the second surface is a light-facing surface 101, and the other is a backlight surface 102. In this embodiment, the first surface is the light-facing surface 101, and the second surface is the backlight surface 102. The P regions 12 are sequentially arranged at intervals on the light-facing surface 101 of the silicon substrate 1, and the N regions 11 are sequentially arranged at intervals on the backlight surface 102 of the silicon substrate 1. Of course, the P regions 12 can also be sequentially arranged at intervals on the backlight surface 102 of the silicon substrate 1, and the N regions 11 can be sequentially arranged at intervals on the light-facing surface 101 of the silicon substrate 1.

[0122] In the embodiment of the utility model, there are multiple N regions 11 and P regions 12, and two adjacent N regions 11 are provided with a first isolation region 16, and two adjacent N regions 11 are provided with a second isolation region 17. Of course, the first isolation region 16 may not be provided between two adjacent N regions 11, and the second isolation region 17 may not be provided between two adjacent N regions 11.

[0123] As an embodiment of the present utility model, a first surface of a silicon substrate 1 is provided with a plurality of N regions 11 and a plurality of first isolation regions 16, and the N regions 11 and the first isolation regions 16 are alternately arranged in sequence; a second surface of the silicon substrate 1 has a plurality of P regions 12 and a plurality of second isolation regions 17, and the P regions 12 and the second isolation regions 17 are alternately arranged in sequence; an N-type doped polysilicon layer 2 is provided on the N region 11 and does not cover the first isolation region 16; a P-type doped polysilicon layer 3 is provided on the P region 12 and does not cover the second isolation region 17.

[0124] In the embodiment of the present invention, the width direction of the second notch 51 and the width direction of the first notch 41 are both along Figure 8 and Fig. 9 In the X direction, the length direction of the second slot 51 and the length direction of the first slot 41 are both along Figure 8 and Fig. 9 The maximum width of the first notch 41 is the maximum dimension of the first notch 41 along the X direction.

[0125] In this embodiment, the N-type doped polysilicon layer 2 only covers the N region 11 and does not cover the first isolation region 16, and the P-type doped polysilicon layer 3 only covers the P region 12 and does not cover the second isolation region 17. The first surface of the silicon substrate 1 is not completely covered by the N-type doped polysilicon layer 2, and the second surface of the silicon substrate 1 is not completely covered by the P-type doped polysilicon layer 3, which can effectively reduce the parasitic absorption of light by the N-type doped polysilicon layer 2 and the P-type doped polysilicon layer 3, thereby improving the conversion efficiency.

[0126] In some other embodiments, the P region 12 may also entirely cover the first surface, and the N region 11 may also entirely cover the second surface.

[0127] In the embodiment of the utility model, the first notch 41 and the second notch 51 can be formed by laser grooving or prepared by other processes. The shapes of the first notch 41 and the second notch 51 can be the same or different. The first notch 41 and the second notch 51 can be square grooves, oval grooves or irregular shapes. Figure 8 and Fig. 9 The shapes of the first notch 41 and the second notch 51 shown in the figure are both irregular, and the widths of the first notch 41 and the second notch 51 are not equal along the length direction thereof.

[0128] A solar cell provided by an embodiment of the utility model is provided with a first notch 41 on a first passivation layer 4 on a side of an N-type doped polysilicon layer 2 facing away from a silicon substrate 1, and a second notch 51 is provided on a second passivation layer 5 on a side of a P-type doped polysilicon layer 3 facing away from the silicon substrate 1, a first electrode 6 passes through the first notch 41 to contact the N-type doped polysilicon layer 2, and a second electrode 7 passes through the second notch 51 to contact the P-type doped polysilicon layer 3. By increasing the width of at least a partial area of ​​at least one second notch 51, the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 can be increased, and the second electrode 7 corresponding to the widened area of ​​the second notch 51 can be in contact with the P-type doped polysilicon layer 3 for conductivity through the second notch 51 with a larger area, so that the second electrode 7 and the P-type doped polysilicon layer 3 form a better ohmic contact, thereby improving the conductive effect of the second electrode 7 and the P-type doped polysilicon layer 3, and the conversion efficiency of the solar cell can be improved; moreover, compared with the contact area between the first electrode 6 and the N-type doped polysilicon layer 2, since the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 is increased, the bonding tension between the P-type doped polysilicon layer 3 and the second electrode 7 is increased, and the connection between the second electrode 7 and the P-type doped polysilicon layer 3 is more stable and reliable, which can improve the reliability of the battery structure.

[0129] In the embodiment of the utility model, the width of at least a partial area of ​​at least one second notch 51 is greater than the maximum width of at least one first notch 41. It can be understood that the width of at least a partial area of ​​at least one second notch 51 is greater than the maximum width of at least one first notch 41 or the width of all areas of at least one second notch 51 is greater than the maximum width of at least one first notch 41. It is sufficient that the width of at least a partial area of ​​the second notch 51 is greater than the maximum width of a first notch 41. The width of at least a certain area of ​​the second notch 51 can be increased, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 in certain areas, increasing the width of the welding area between the second electrode 7 and the welding strip or increasing the width of the entire second electrode 7, and improving the conductive effect and bonding tension of the welding area of ​​the second electrode 7 or the entire second electrode 7 and the P-type doped polysilicon layer 3.

[0130] In the embodiment of the utility model, the first electrode 6 and the second electrode 7 can be prepared by screen printing or electroplating process, the slurry of the first electrode 6 is filled into the first notch 41 and contacts the N-type doped polysilicon layer 2, and the slurry of the second electrode 7 is filled into the second notch 51 and contacts the P-type doped polysilicon layer 3. Since the width of the second notch 51 in a certain area is at least increased, the second electrode 7 corresponding to the widened second notch 51 can have more slurry contacting the P-type doped polysilicon layer 3 through the second notch 51, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0131] As an embodiment of the present invention, the width of all regions of the at least one second notch 51 is greater than the maximum width of the at least one first notch 41 .

[0132] In this embodiment, the width of all areas of at least one second notch 51 is greater than the maximum width of at least one first notch 41, that is, compared with the first notch 41, all areas of at least one second notch 51 are widened, thereby further improving the contact area between the second electrode 7 corresponding to the second notch 51 and the P-type doped polysilicon layer 3, and further improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0133] In practical applications, the width of all areas of one of the second notches 51 may be greater than the maximum width of at least one first notch 41, or the width of all areas of two of the second notches 51 may be greater than the maximum width of at least one first notch 41, or the width of all areas of all the second notches 51 may be greater than the maximum width of at least one first notch 41.

[0134] As a preferred embodiment of the present invention, the width of all regions of any second notch 51 is greater than the maximum width of any first notch 41 .

[0135] In this embodiment, the width of all areas of each second notch 51 is greater than the maximum width of each first notch 41. Compared with the first notch 41, the width of all areas of each second notch 51 is widened, which can increase the contact area between each second electrode 7 and the P-type doped polysilicon layer 3, and further improve the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0136] As an embodiment of the present invention, the second notch 51 includes a first area 511 corresponding to the welding position of the second electrode 7 and a second area 512 corresponding to the non-welding position of the second electrode 7 along its length direction, and the width d1 of the first area 511 of the second notch 51 is greater than the maximum width of the first notch 41.

[0137] In this embodiment, the first area 511 of the second notch 51 corresponds to the area corresponding to the welding position of the second electrode 7; the second area 512 of the second notch 51 corresponds to the area corresponding to the non-welding position of the second electrode 7. The first area 511 and the second area 512 are alternately arranged in sequence along the length direction of the second notch 51 and are connected to each other. Figure 8 Three are shown in FIG.

[0138] Since the width of the first area 511 of the second notch 51 is set to be greater than the maximum width of the first notch 41, when the second electrode 7 is screen-printed, the width of the second electrode 7 corresponding to the second notch 51 can be made greater than the maximum width of the first notch 41, that is, the width of the welding area of ​​the second electrode 7 is widened, thereby improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3, and increasing the welding contact area between the second electrode 7 and the welding strip, thereby improving the welding effect.

[0139] As an embodiment of the present invention, the width of the first region 511 is greater than or equal to the width d3 of the second region 512 .

[0140] In this embodiment, the width d1 of the first region 511 can be greater than the width d3 of the second region 512, and the width d1 of the first region 511 is greater than the maximum width of the first notch 41, so that the width of the second electrode 7 at the welding position is greater than the width of the non-welding position, which can improve the welding effect between the second electrode 7 and the welding strip; and because the width of the first region 511 is greater than the maximum width of the first notch 41, the width of the welding position and the width of the non-welding position of the second electrode 7 are both greater than the maximum width of the first notch 41, that is, the width of the welding position and the width of the non-welding position of the second electrode 7 are both widened, which is conducive to increasing the contact area between the entire second electrode 7 and the P-type doped polysilicon layer 3. In addition, the width of the first region 511 can also be equal to the width of the second region 512, which is convenient for the processing of the second notch 51, and compared with the first notch 41, the width of the first region 511 and the width of the second region 512 are also widened, that is, all regions of the second electrode 7 are widened, which can improve the contact area between the entire second electrode 7 and the P-type doped polysilicon layer 3.

[0141] As an embodiment of the present invention, the first notch 41 includes a third area 411 corresponding to the welding position of the first electrode 6, and a fourth area 412 corresponding to the non-welding position of the first electrode 6, and the width d1 of the first area 511 of the second notch 51 is greater than the width d2 of the third area 411 of the first notch 41.

[0142] In this embodiment, the third area 411 of the first notch 41 corresponds to the area corresponding to the welding position of the first electrode 6; the fourth area 412 of the first notch 41 corresponds to the area corresponding to the non-welding position of the first electrode 6. The third area 411 and the fourth area 412 are alternately arranged in sequence along the length direction of the first notch 41 and are connected to each other. Fig. 9 Three are shown in FIG. 4 , and the width d2 of the third area 411 of the first notch 41 is the maximum width of the first notch 41 .

[0143] Among them, since the width d1 of the first area 511 of the second notch 51 is greater than the width d2 of the third area 411 of the first notch 41, the width of the second electrode 7 corresponding to the first area 511 is greater than the width of the first electrode 6 corresponding to the third area 411, that is, the width of the welding area of ​​the second electrode 7 is greater than the width of the welding area of ​​the first electrode 6, which can improve the conductive effect and bonding tension between the welding area of ​​the second electrode 7 and the P-type doped polysilicon layer 3, and increase the welding contact area between the welding area of ​​the second electrode 7 and the welding strip, thereby improving the welding effect.

[0144] As an embodiment of the present invention, a width d3 of the second area 512 of the second notch 51 is greater than a width d4 of the fourth area 412 of the first notch 41 .

[0145] In this embodiment, the width d3 of the second area 512 of the second notch 51 is greater than the width d4 of the fourth area 412 of the first notch 41, so the width of the second electrode 7 corresponding to the second area 512 is greater than the width of the first electrode 6 corresponding to the fourth area 412, that is, the width of the non-welding area of ​​the second electrode 7 is greater than the width of the non-welding area of ​​the first electrode 6, which can further enhance the conductive effect and bonding tension between the non-welding area of ​​the second electrode 7 and the P-type doped polysilicon layer 3.

[0146] As an embodiment of the present invention, a width d4 of the fourth area 412 of the first notch 41 is greater than a width d2 of the third area 411 of the first notch 41 .

[0147] As an embodiment of the present invention, the area of ​​any second notch 51 is greater than the area of ​​any first notch 41. In the embodiment of the present invention, the area of ​​the first notch 41 is the area of ​​the cross section of the first notch 41; the area of ​​the second notch 51 is the area of ​​the cross section of the second notch 51.

[0148] In this embodiment, the area of ​​the second notch 51 of each P region 12 is larger than the area of ​​the first notch 41 of each N region 11, so that the area of ​​each second notch 51 is enlarged, which can increase the contact area between each second electrode 7 and the P-type doped polysilicon layer 3, thereby improving the conductive effect and bonding tension between the second electrode 7 and the P-type doped polysilicon layer 3.

[0149] As an embodiment of the present invention, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is 1-1.5 and is not equal to 1.

[0150] Among them, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 can be: 1.01, or 1.05, or 1.1, or 1.15, or 1.2, or 1.23, or 1.28, or 1.3, or 1.35, or 1.38, or 1.4, or 1.42, or 1.47, or 1.5.

[0151] In this embodiment, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is set to 1 to 1.5, and is not equal to 1. That is, the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 and the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 can have a relatively suitable difference, and it is convenient to set the first notch 41 and the second notch 51.

[0152] As an embodiment of the utility model, the ratio of the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 to the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 is 1.01 to 1.2, which can further reduce the difference between the area of ​​the P-type doped polysilicon layer 3 and the area of ​​the N-type doped polysilicon layer 2, which is conducive to making the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 and the contact area between the first electrode 6 and the N-type doped polysilicon layer 2 have a more appropriate difference.

[0153] As an embodiment of the present invention, the widths of the first notches 41 of at least two N regions 11 are unequal.

[0154] In this embodiment, the widths of the first notches 41 of at least two N regions 11 are not equal. It can be understood that, among the multiple N regions 11, the width of the first notch 41 of at least one N region 11 is not equal to the width of the first notch 41 of at least one N region 11 in the other N regions 11. In this way, the width of the first electrode 6 can be changed by adjusting the width of the first notch 41 corresponding to at least one of the N regions 11, so that the width of at least one first electrode 6 is different from the width of other first electrodes 6, and the differentiated design of the width of the first electrode 6 can be realized, which can improve the light absorption range and photoelectric conversion efficiency of the solar cell and maximize the use of light energy resources.

[0155] As an embodiment of the present invention, the widths of the second notches 51 of at least two P regions 12 are unequal.

[0156] In this embodiment, the width of the second notch 51 of at least one P region 12 is not equal to the width of the second notch 51 of at least one P region 12. It can be understood that, among the multiple P regions 12, the width of the second notch 51 of at least one P region 12 is not equal to the width of the second notch 51 of at least one P region 12 in the other P regions 12. The width of the second electrode 7 can be changed by adjusting the width of the second notch 51 corresponding to at least one of the P regions 12, so that the width of at least one second electrode 7 can be different from the width of other second electrodes 7, and the differentiated width design of the second electrode 7 can be realized, which can further improve the light absorption range and photoelectric conversion efficiency of the solar cell and maximize the use of light energy resources.

[0157] As an embodiment of the utility model, a plurality of first countersunk holes 21 are arranged in an area of ​​the N-type doped polysilicon layer 2 corresponding to a first notch 41, and the first electrode 6 passes through the first notch 41 to contact each first countersunk hole; a plurality of second countersunk holes 31 are arranged in an area of ​​the P-type doped polysilicon layer 3 corresponding to a second notch 51, and the second electrode 7 passes through the second notch 51 to contact each second countersunk hole, and the number of second countersunk holes 31 corresponding to each second notch 51 is greater than the number of first countersunk holes 21 corresponding to a first notch 41.

[0158] In this embodiment, by setting a plurality of first countersunk holes 21 in the region of the N-type doped polysilicon layer 2 corresponding to the first notch 41, and setting a plurality of second countersunk holes 31 in the region of the P-type doped polysilicon layer 3 corresponding to a second notch 51, the first electrode 6 enters the first notch 41 and can enter the first countersunk hole 21 to contact the first countersunk hole 21, which can improve the contact effect between the first electrode 6 and the N-type doped polysilicon layer 2, and the second electrode 7 enters the second notch 51 and can enter the second countersunk hole 31 to contact the second countersunk hole 31, which can improve the contact effect between the second electrode 7 and the P-type doped polysilicon layer 3; and, since the number of second countersunk holes 31 corresponding to one second notch 51 is greater than the number of first countersunk holes 21 corresponding to one first notch 41, the second electrode 7 can contact with a larger number of second countersunk holes 31, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3. Wherein, the first countersunk hole 21 and the second countersunk hole 31 can both be circular countersunk holes.

[0159] As an embodiment of the present invention, the diameter of the second counterbore 31 is larger than the diameter of the first counterbore 21 .

[0160] In this embodiment, since the aperture of the second countersunk hole 31 is larger than the aperture of the first countersunk hole 21 , the area of ​​each second countersunk hole 31 is larger than the area of ​​each first countersunk hole 21 , which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3 .

[0161] As an embodiment of the present invention, the distribution density of the second countersunk holes 31 is greater than the distribution density of the first countersunk holes 21 .

[0162] In this embodiment, the distribution density of the second countersunk holes 31 is greater than the distribution density of the first countersunk holes 21. It can be understood that, within a unit area, the number of second countersunk holes 31 is greater than the number of first countersunk holes 21, so that the second electrode 7 can contact with more areas of the second countersunk holes 31, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0163] As an embodiment of the present invention, the depth of the second counterbore 31 is greater than the depth of the first counterbore 21 .

[0164] In this embodiment, since the depth of the second countersunk hole 31 is greater than the depth of the first countersunk hole 21, the second electrode 7 can enter the deeper second countersunk hole 31, thereby making the second electrode 7 have more contact area with the P-type doped polysilicon layer 3, which can further increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0165] As an embodiment of the present invention, the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2 .

[0166] In this embodiment, after the slurry of the second electrode 7 passes through the second groove 51, the slurry of the second electrode 7 can enter the P-type doped polysilicon layer 3, and after the slurry of the first electrode 6 passes through the first groove 41, the slurry of the first electrode 6 can enter the N-type doped polysilicon layer 2, and the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2, which can also increase the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0167] Among them, when the first electrode 6 and the second electrode 7 are prepared by the screen printing process, the slurry ratio of the second electrode 7 and the first electrode 6 can be adjusted so that the slurries of the second electrode 7 and the first electrode 6 have different burn-through capabilities, so that the burn-through capability of the slurry of the second electrode 7 is greater than the burn-through capability of the slurry of the first electrode 6, so that the depth of the second electrode 7 entering the P-type doped polysilicon layer 3 is greater than the depth of the first electrode 6 entering the N-type doped polysilicon layer 2, thereby increasing the contact area between the second electrode 7 and the P-type doped polysilicon layer 3.

[0168] As an embodiment of the present invention, the ratio of the depth of the second electrode 7 penetrating into the P-type doped polysilicon layer 3 to the depth of the first electrode 6 penetrating into the N-type doped polysilicon layer 2 is 1.01-2.

[0169] In this embodiment, the ratio of the depth of the second electrode 7 penetrating into the P-type doped polysilicon layer 3 to the depth of the first electrode 6 penetrating into the N-type doped polysilicon layer 2 may be 1.01, or 1.20, or 1.35, or 1.55, or 1.60, or 1.80, or 1.90, or 2.0.

[0170] As an embodiment of the present invention, the solar cell includes multiple first electrodes 6 and multiple second electrodes 7 , at least one second electrode 7 has a width greater than that of at least one first electrode 6 , and at least one second electrode 7 has a width less than that of at least one first electrode 6 .

[0171] In this embodiment, a plurality of first electrodes 6 are respectively arranged in the N region 11, and a plurality of second electrodes 7 are respectively arranged in the P region 12. Among them, the width of at least one second electrode 7 is greater than the width of at least one first electrode 6, and the width of at least one second electrode 7 is less than the width of at least one first electrode 6, so that the width of the second electrode 7 is not consistent with the width of the first electrode 6, and the width difference between the first electrode 6 and the second electrode 7 can be flexibly adjusted instead of setting an electrode with a single width, which can improve the light absorption range and photoelectric conversion efficiency of the solar cell, and maximize the use of light energy resources, and greatly increase the probability of collecting photocurrent without affecting the production capacity.

[0172] In this embodiment, the width of the first electrode 6 can be adjusted by adjusting the width of the first notch 41 corresponding to each first electrode 6, and the width of the second electrode 7 can be adjusted by adjusting the width of the second notch 51 corresponding to each second electrode 7. This can achieve an optimized design of the widths of the first electrode 6 and the second electrode 7, thereby improving battery efficiency.

[0173] As an embodiment of the utility model, the first passivation layer 4 and the second passivation layer 5 are both at least one or a combination of aluminum oxide film layers, silicon oxide film layers, silicon nitride film layers, silicon carbide film layers, and silicon oxynitride film layers. For example, in some embodiments, the first passivation layer 4 and the second passivation layer 5 can both include aluminum oxide film layers and silicon nitride film layers stacked in sequence.

[0174] Please refer to Figure 7 As an embodiment of the utility model, the solar cell further includes a first tunneling layer 8 disposed between the N-type doped polysilicon layer 2 and the surface of the silicon substrate 1, and a second tunneling layer 9 disposed between the P-type doped polysilicon layer 3 and the surface of the silicon substrate 1.

[0175] In this embodiment, the first tunneling layer 8 and the second tunneling layer 9 may be silicon oxide layers. The cell efficiency of the solar cell may be further improved by utilizing the tunneling passivation effect of the first tunneling layer 8 and the second tunneling layer 9 .

[0176] Embodiment 3

[0177] The present utility model also provides a battery assembly, which includes the solar cell of the above-mentioned embodiment 1 or embodiment 2. It should be noted that the battery assembly and the solar cell have the same or similar beneficial effects, and the relevant parts between the two can be referenced to each other. In order to avoid repetition, they will not be repeated here.

[0178] Embodiment 4

[0179] The present utility model also provides a photovoltaic system, which includes the battery assembly of the above-mentioned embodiment 3. It should be noted that the photovoltaic system has the same or similar beneficial effects as the solar cell, and the relevant parts between the two can be referenced to each other. In order to avoid repetition, it will not be repeated here.

[0180] A solar cell provided by an embodiment of the utility model is provided with at least one N region and at least one P region, an N-type doped polysilicon layer is provided in the N region, a P-type doped polysilicon layer is provided in the P region, a first notch is provided in a first passivation layer on a side of the N-type doped polysilicon layer facing away from a silicon substrate, and a second notch is provided in a second passivation layer on a side of the P-type doped polysilicon layer facing away from the silicon substrate, a first electrode passes through the first notch to contact the N-type doped polysilicon layer, and a second electrode passes through the second notch to contact the P-type doped polysilicon layer, so that the width of at least a part of the at least one second notch can be increased, so that the width of at least a part of the at least one second notch is greater than the maximum width of the at least one first notch, so that the contact area between at least a part of the second electrode and the P-type doped polysilicon layer can be increased, so that the second electrode and the P-type doped polysilicon layer form a good ohmic contact, and the conductive effect of the P region can be improved, thereby improving the conversion efficiency of the battery; and, since the contact area between the second electrode and the P-type doped polysilicon layer is increased, the bonding tension between the second electrode and the P-type doped polysilicon layer can be increased, thereby improving the reliability of the battery structure.

[0181] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A solar cell, characterized in that: include: A silicon substrate, wherein the silicon substrate comprises at least one N region and at least one P region, wherein the N region and the P region are located on the same surface of the silicon substrate, or the N region and the P region are located on two opposite surfaces of the silicon substrate; An N-type doped polysilicon layer is disposed on the N region; A P-type doped polysilicon layer is disposed on the P region; A first passivation layer located in the N region is provided on a side of the N-type doped polysilicon layer away from the silicon substrate, and a first notch is provided through the first passivation layer along a thickness direction thereof; A second passivation layer located in the P region is provided on a side of the P-type doped polysilicon layer away from the silicon substrate, and a second notch is provided through the second passivation layer along the thickness direction thereof; a first electrode disposed in the N region, the first electrode passing through the first notch and contacting the N-type doped polysilicon layer; a second electrode disposed in the P region, the second electrode passing through the second notch and contacting the P-type doped polysilicon layer; Wherein, the width of at least a partial area of ​​at least one of the second notches is greater than the maximum width of at least one of the first notches.

2. The solar cell according to claim 1, characterized in that The width of all regions of at least one of the second notches is greater than the maximum width of at least one of the first notches.

3. The solar cell according to claim 1, characterized in that The width of all regions of any one of the second notches is greater than the maximum width of any one of the first notches.

4. The solar cell according to claim 1, characterized in that The second notch includes a first area corresponding to a welding position of the second electrode and a second area corresponding to a non-welding position of the second electrode, and a width of the first area of ​​the second notch is greater than a maximum width of the first notch.

5. The solar cell according to claim 4, characterized in that: The width of the first region is greater than or equal to the width of the second region.

6. The solar cell according to claim 4, characterized in that: The first notch includes a third area corresponding to a welding position of the first electrode and a fourth area corresponding to a non-welding position of the first electrode, and a width of the first area of ​​the second notch is greater than a width of the third area of ​​the first notch.

7. The solar cell according to claim 6, characterized in that: The width of the second area of ​​the second notch is greater than the width of the fourth area of ​​the first notch.

8. The solar cell according to claim 1, characterized in that An area of ​​any one of the second notches is greater than an area of ​​any one of the first notches.

9. The solar cell according to claim 1, characterized in that: A ratio of a contact area between the second electrode and the P-type doped polysilicon layer to a contact area between the first electrode and the N-type doped polysilicon layer is 1 to 1.5 and is not equal to 1.

10. The solar cell according to claim 1, characterized in that: A ratio of a contact area between the second electrode and the P-type doped polysilicon layer to a contact area between the first electrode and the N-type doped polysilicon layer is 1.01 to 1.

2.

11. The solar cell according to claim 1, characterized in that: The widths of the first notches in at least two of the N regions are unequal.

12. The solar cell according to claim 1, characterized in that The widths of the second notches in at least two of the P regions are unequal.

13. The solar cell according to claim 1, characterized in that A plurality of first countersunk holes are provided in the area of ​​the N-type doped polysilicon layer corresponding to the first notch, and the first electrode passes through the first notch and contacts with each of the first countersunk holes; A plurality of second countersunk holes are arranged in the area of ​​the P-type doped polysilicon layer corresponding to the second notch, the second electrode passes through the second notch and contacts each of the second countersunk holes, and the number of the second countersunk holes corresponding to each of the second notches is greater than the number of the first countersunk holes corresponding to each of the first notches.

14. The solar cell according to claim 13, characterized in that: The aperture of the second counterbore is larger than the aperture of the first counterbore.

15. The solar cell according to claim 13, characterized in that: The distribution density of the second countersunk holes is greater than the distribution density of the first countersunk holes.

16. The solar cell according to claim 13, characterized in that: The depth of the second counterbore is greater than the depth of the first counterbore.

17. The solar cell according to claim 1, characterized in that A depth of the second electrode entering the P-type doped polysilicon layer is greater than a depth of the first electrode entering the N-type doped polysilicon layer.

18. The solar cell according to claim 1, characterized in that The ratio of the depth of the second electrode entering the P-type doped polysilicon layer to the depth of the first electrode entering the N-type doped polysilicon layer is 1.01-2.

19. The solar cell according to claim 1, characterized in that The solar cell is a back contact solar cell, and the N region and the P region are located on the same surface of the silicon substrate.

20. The solar cell according to claim 1, characterized in that The solar cell is a double-sided solar cell, and the N region and the P region are respectively located on two opposite sides of the silicon substrate.

21. A battery assembly, characterized in that: Comprising the solar cell according to any one of claims 1 to 20.

22. A photovoltaic system, characterized in that: Comprising a battery assembly as claimed in claim 21.

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