Back contact solar cell, cell module and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a back contact solar cell, a cell assembly and a photovoltaic system, the back contact solar cell comprises a silicon substrate, the backlight surface of the silicon substrate is provided with a first area and a second area; the first transmission layer is arranged in the first area; the second transmission layer is arranged in the second area; the laser absorption protection layer is arranged on the surface, away from the backlight surface, of the second transmission layer; the first conductive layer is arranged on the surface, away from the backlight surface, of the first transmission layer; the second conducting layer is arranged on the side, away from the backlight face, of the laser absorption protection layer, the second conducting layer covers the electrode contact area of the laser absorption protection layer and the second transmission layer, and an insulating groove is formed in the area, close to the first conducting layer, of the second conducting layer; and the second conductive layer forms a warping part which warps from the inner side of the insulating groove to the outer side of the insulating groove at the notch edge of the insulating groove. According to the back contact solar cell, the second conductive layer and the first conductive layer can be prevented from being communicated to form an electric leakage path, and the production yield of the cell can be improved.

Description

Technical Field

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

[0002] Solar energy is an inexhaustible renewable energy source, which is of great significance to environmental protection. The effective utilization of solar energy has become the consensus of mankind. The utilization of solar energy, especially photovoltaic power generation technology, is the most promising renewable energy technology. Solar cells have the advantages of low energy consumption, rich and pollution-free raw materials, and easy large-scale production, and have been industrialized. The products are widely used in fields such as ground photovoltaic power stations, building-integrated photovoltaics, and rooftop power stations. Among them, the back-contact (BC) solar cell is a research hotspot in the industry. The back surface of the back-contact solar cell is provided with an electron selective transport layer and a hole selective transport layer. Its biggest feature is that the metal electrode is located on the back surface of the battery, and there is no metal electrode occlusion on the front surface, which improves the light utilization rate. Therefore, it has a higher short-circuit current and conversion efficiency.

[0003] In the prior art, for back-contact solar cells, especially HBC cells, a conductive layer is usually deposited on the collector to solve the problem of poor contact between the metal grid line and the transport layer. Due to the special structure of the back-contact solar cell, the PN regions are adjacent in an alternating manner. After the conductive layer is deposited, it will cause the PN regions to be directly connected, resulting in circuit short-circuit leakage. Therefore, it is usually necessary to perform laser etching on the conductive layer at the PN adjacent position to form an insulating groove to form leakage protection. However, in the actual production process, due to problems with the laser itself, the conductive layer on the inner wall of the insulating groove cannot be completely removed, and the conductive layer at the edge of the groove opening of the insulating groove is too flat, and the conductive layer is easy to cover the inner wall of the insulating groove, which easily causes the conductive layer of the PN region to be connected and leak electricity, resulting in a low production yield. Summary of the Utility Model

[0004] The utility model provides a back-contact solar cell, aiming to solve the problem that the conductive layer of the PN region in the existing back-contact solar cell is easily connected and leaks electricity, resulting in a low production yield.

[0005] The utility model is realized as follows. A back-contact solar cell is provided, including:

[0006] A silicon substrate, the silicon substrate includes a backlight surface, and a first region and a second region are provided on the backlight surface of the silicon substrate;

[0007] A first transport layer provided in the first region;

[0008] A second transport layer provided in the second region, and the doping type of the second transport layer is different from that of the first transport layer;

[0009] A laser absorption protection layer is disposed on a side of the second transmission layer away from the backlight surface, and an electrode contact area of the second transmission layer is exposed;

[0010] A first conductive layer is disposed on a side of the first transmission layer away from the backlight surface;

[0011] A second conductive layer is disposed on a side of the laser absorption protection layer away from the backlight surface. The second conductive layer covers the laser absorption protection layer and the electrode contact area of the second transmission layer. An insulating groove is provided in a region of the second conductive layer close to the first conductive layer, and a warping portion that warps from the inner side of the insulating groove to the outer side of the insulating groove is formed at an edge of the notch of the insulating groove.

[0012] Preferably, it further includes:

[0013] A first electrode disposed in the first region, in contact with the first conductive layer;

[0014] A second electrode disposed in the second region, in contact with the second conductive layer corresponding to the electrode contact area. The insulating groove is located between the first electrode and the second electrode.

[0015] Preferably, the first transmission layer includes a first passivation layer and a first doped layer that are sequentially stacked on the backlight surface, and the first conductive layer is disposed on a side of the first doped layer away from the silicon substrate;

[0016] The second transmission layer includes a second passivation layer and a second doped layer that are sequentially stacked on the backlight surface. The doping types of the first doped layer and the second doped layer are different, and the laser absorption protection layer is disposed on a side of the second doped layer away from the silicon substrate.

[0017] Preferably, both the first passivation layer and the second passivation layer are amorphous silicon; both the first doped layer and the second doped layer are doped amorphous silicon or doped microcrystalline silicon;

[0018] Or, both the first passivation layer and the second passivation layer are silicon oxide; the first doped layer and the second doped layer are doped polysilicon or doped microcrystalline silicon;

[0019] Or, the first passivation layer and the second passivation layer are amorphous silicon and silicon oxide respectively, and the first doped layer and the second doped layer are doped polysilicon and doped microcrystalline silicon respectively.

[0020] Preferably, the laser absorption protection layer includes:

[0021] An insulating layer is disposed on a side of the second transmission layer away from the silicon substrate, and an electrode contact area of the second transmission layer is exposed;

[0022] A laser absorption layer is disposed on a side of the insulating layer away from the silicon substrate, and exposes an electrode contact area of the second transmission layer.

[0023] Preferably, the insulating layer is one or a stack of at least two of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon carbide layer.

[0024] Preferably, the laser absorption layer is one or a stack of at least two of an amorphous silicon layer, a nanocrystalline silicon layer, a microcrystalline silicon layer, and a polycrystalline silicon layer.

[0025] Preferably, the laser absorption layer includes:

[0026] A first laser absorption layer is disposed on a side of the insulating layer away from the silicon substrate, and exposes the electrode contact area;

[0027] A second laser absorption layer is disposed on a side of the first laser absorption layer away from the silicon substrate, and exposes the electrode contact area.

[0028] Preferably, the first laser absorption layer is an intrinsic amorphous silicon layer, and the second laser absorption layer is a doped amorphous silicon layer.

[0029] Preferably, the insulating groove at least partially penetrates the laser absorption layer.

[0030] Preferably, the total thickness of the laser absorption layer is 5 to 50 nanometers.

[0031] Preferably, the thickness of the second conductive layer is 40 to 150 micrometers.

[0032] Preferably, the height of the warped portion is 0.2 to 2 micrometers.

[0033] Preferably, the angle B between the warped portion and the surface of the second conductive layer close to the silicon substrate is 15 to 150°.

[0034] Preferably, the angle B between the warped portion and the surface of the second conductive layer close to the silicon substrate is 90 to 150°.

[0035] Preferably, the silicon substrate further includes a light-facing surface opposite to the backlight surface, and the back-contact solar cell further includes:

[0036] A front passivation layer disposed on the light-facing surface;

[0037] An antireflection film layer disposed on a side of the front passivation layer away from the silicon substrate.

[0038] The present invention further provides a battery module, including the above-mentioned back-contact solar cell.

[0039] The present utility model further provides a photovoltaic system, including the above-mentioned battery assembly.

[0040] A back-contact solar cell provided by the present utility model is provided with a laser absorption protection layer on a side of the second transmission layer away from the backlight surface, and a second conductive layer is disposed on a side of the laser absorption protection layer away from the backlight surface. When forming an insulating groove during the laser etching process of the second conductive layer, due to the heat absorption and expansion of the laser absorption protection layer, the laser absorption protection layer pushes the edge portion of the second conductive layer close to the notch of the insulating groove outwards to form a warped portion, avoiding the attachment of residues of the second conductive layer to the inner wall of the insulating groove and connecting with the first conductive layer to form a leakage path, thereby improving the production yield of the battery; moreover, the warped portion formed at the notch edge of the insulating groove can block the damage to the second conductive layer and the silicon substrate during the subsequent wet cleaning process, and can further improve the production yield of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of a back-contact solar cell provided by an embodiment of the present utility model;

[0042] Figure 2 is a partial structural schematic diagram of a back-contact solar cell provided by an embodiment of the present utility model;

[0043] Figure 3 is an SEM image of the warped portion of the second conductive layer of a back-contact solar cell provided by an embodiment of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to make the objectives, technical solutions and advantages of the present utility model more clear and understandable, the present utility model 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 utility model and are not used to limit the present utility model.

[0045] A back-contact solar cell provided by an embodiment of the present utility model is provided with a laser absorption protection layer on a side of the second transmission layer away from the backlight surface, and a second conductive layer is disposed on a side of the laser absorption protection layer away from the backlight surface. When forming an insulating groove during the laser etching process of the second conductive layer, due to the heat absorption and expansion of the laser absorption protection layer, the laser absorption protection layer pushes the edge portion of the second conductive layer close to the notch of the insulating groove outwards to form a warped portion, avoiding the attachment of residues of the second conductive layer to the inner wall of the insulating groove and connecting with the first conductive layer to form a leakage path, thereby improving the production yield of the battery; moreover, the warped portion formed at the notch edge of the insulating groove can block the damage to the second conductive layer and the silicon substrate during the subsequent wet cleaning process, and can further improve the production yield of the battery.

[0046] Please refer to Figure 1 - Figure 2 , an embodiment of the present utility model provides a back-contact solar cell, including:

[0047] A silicon substrate 1, comprising a backlight surface, wherein the backlight surface is provided with a first region 111 and a second region 112;

[0048] A first transmission layer 2 provided in the first region 111;

[0049] a second transmission layer 3 provided in the second region 112 , wherein the second transmission layer 3 has a different doping type from the first transmission layer 2 ;

[0050] The laser absorption protection layer 4 is provided on a side of the second transmission layer 2 away from the backlight surface and exposes the electrode contact area of the second transmission layer 3;

[0051] A first conductive layer 5 is provided on a side of the first transmission layer 2 away from the backlight side;

[0052] The second conductive layer 6 is arranged on the side of the laser absorption protection layer 4 away from the backlight surface. The second conductive layer 6 covers the laser absorption protection layer 4 and the electrode contact area. An insulating groove 61 is provided in the area of the second conductive layer 6 close to the first conductive layer 5. The second conductive layer 6 forms a warped portion 62 at the edge of the groove of the insulating groove 61, which is warped from the inside of the insulating groove 61 to the outside of the insulating groove 61.

[0053] In the embodiment of the present invention, the area to the right of the dotted line L on the backlight surface is the first area 111, and the area to the left of the dotted line L on the backlight surface is the second area 112. The first areas 111 and the second areas 112 are alternately distributed along the first direction. It should be noted that the dotted line L does not actually exist in the back-contact solar cell and is merely a schematic representation of the first areas 111 and the second areas 112.

[0054] One of the first region 111 and the second region 112 is a P region, and the other is an N region. For example, the first region 111 is a P region, and the second region 112 is an N region; or the first region 111 is an N region, and the second region 112 is a P region. The first regions 111 and the second regions 112 are alternately distributed on the backlight surface of the silicon substrate 1.

[0055] In an embodiment of the present invention, the silicon substrate 1 includes a light-facing surface 12 and a backlight surface arranged opposite to the light-facing surface 12. The light-facing surface 12 is the side of the silicon substrate 1 facing the sunlight when the back-contact solar cell is working, and the backlight surface is the side of the silicon substrate 1 facing away from the sunlight when the back-contact solar cell is working.

[0056] In the embodiment of the present utility model, the silicon substrate 1 can be a silicon base substrate 1, and the doping type can be N-type doping, P-type doping, etc., and the doping type of the silicon base substrate 1 is not specifically limited. The front side and the backlight side of the silicon base substrate 1 are distributed oppositely. Among them, the doping types of the first transmission layer 2 and the second transmission layer 3 are different, that is, one of them is N-type doping and the other is P-type doping.

[0057] In the embodiment of the present utility model, a back-contact solar cell is provided. By providing a laser absorption protection layer 4 on the side of the second transmission layer 3 away from the backlight side, and a second conductive layer 6 is provided on the side of the laser absorption protection layer 4 away from the backlight side. When forming an insulating groove 61 during the laser etching process of the second conductive layer 6, due to the heat absorption and expansion of the laser absorption protection layer 4, the laser absorption protection layer 4 pushes the edge part of the second conductive layer 6 close to the notch of the insulating groove 61 outward to form a warping part 62, avoiding the residue of the second conductive layer 6 at the position of the insulating groove 61 from adhering to the inside of the insulating groove 61 and communicating with the first conductive layer 5 to form a leakage path, that is, preventing the conductive layers of the P region and the N region from communicating and leaking electricity, thereby improving the production yield of the battery; moreover, the warping part 62 formed at the notch edge of the insulating groove 61 can block the etching solution during the wet cleaning process, avoiding the etching solution from damaging the second conductive layer 6 and the silicon substrate 1, and can further improve the production yield of the battery.

[0058] In the embodiment of the present utility model, when forming an insulating groove 61 during the laser etching process of the second conductive layer 6, due to the heat absorption and expansion of the laser absorption protection layer 4, the second conductive layer 6 attached to the inner wall of the insulating groove 61 is pushed outward by the laser absorption protection layer 4 and separated from the laser absorption protection layer 4, causing the second conductive layer 6 attached to the inner wall of the insulating groove 61 to warp away from the laser absorption protection layer 4 to form a warping part 62, thereby avoiding the second conductive layer 6 from adhering to the inner wall of the insulating groove 61 and preventing the residue of the second conductive layer 6 from adhering to the inside of the insulating groove 61 and communicating with the first conductive layer 5 to form a leakage path. Among them, as Figure 3 shown, the warping part 62 at the notch edge position of the insulating groove 61 of the second conductive layer 6 can be arc-shaped, inclined-plane-shaped or irregularly curled, and the warping part 62 can also include arc-shaped, inclined-plane-shaped or irregularly curled at the same time.

[0059] As an embodiment of the present utility model, it further includes:

[0060] A first electrode 7 provided in the first region 111, in contact with the first conductive layer 5;

[0061] A second electrode 8 provided in the second region 112, in contact with the second conductive layer 6 corresponding to the electrode contact region, and the insulating groove 61 is located between the first electrode 7 and the second electrode 8.

[0062] In this embodiment, the polarities of the first electrode 7 and the second electrode 8 are opposite, that is, one of the first electrode 7 and the second electrode 8 is the positive electrode and the other is the negative electrode. The first electrode 7 is in contact with the first transmission layer 2 through the first conductive layer 5, and the second electrode 8 is in contact with the second transmission layer 3 through the second conductive layer 6. Among them, the first conductive layer 5 and the second conductive layer 6 are insulated from each other by the insulating groove 61 to prevent the first conductive layer 5 and the second conductive layer 6 from being electrically connected and leaking electricity.

[0063] As an embodiment of the present invention, the first transmission layer 2 includes a first passivation layer 21 and a first doping layer 22 which are sequentially stacked on the backlight surface, and the first conductive layer 5 is disposed on the side of the first doping layer 22 away from the silicon substrate 1;

[0064] The second transmission layer 3 includes a second passivation layer 31 and a second doping layer 32 which are sequentially stacked on the backlight surface. The doping types of the first doping layer 22 and the second doping layer 32 are different, and the laser absorption protection layer 4 is disposed on the side of the second doping layer 32 away from the silicon substrate 1.

[0065] In this embodiment, the doping types of the first doping layer 22 and the second doping layer 32 are different, that is, one of them is an N-type doping layer and the other is a P-type doping layer. Among them, the materials of the first passivation layer 21 and the second passivation layer 31 may be the same or different. The materials of the first doping layer 22 and the second doping layer 32 may be the same or different. The first electrode 7 is in contact with the first doping layer 22 through the first conductive layer 5, and the second electrode 8 is in contact with the second doping layer 32 through the second conductive layer 6, thereby improving the contact effect between the electrode and the doping layer.

[0066] As an embodiment of the present invention, the first passivation layer 21 and the second passivation layer 31 are both amorphous silicon; the first doping layer 22 and the second doping layer 32 are both doped amorphous silicon or doped microcrystalline silicon;

[0067] Or, the first passivation layer 21 and the second passivation layer 31 are both silicon oxide; the first doping layer 22 and the second doping layer 32 are doped polysilicon or doped microcrystalline silicon;

[0068] Or, the first passivation layer 21 and the second passivation layer 31 are amorphous silicon or silicon oxide respectively, and the first doping layer 22 and the second doping layer 32 are doped polysilicon and doped microcrystalline silicon respectively.

[0069] In this embodiment, the materials of the first passivation layer 21 and the second passivation layer 31 are both selected from amorphous silicon, and the materials of the first doping layer 22 and the second doping layer 32 are both selected from doped amorphous silicon or doped microcrystalline silicon. That is, this back-contact solar cell is an HBC (Heterojunction Back Contact) cell, and this back-contact solar cell has advantages such as a high open-circuit voltage, a low process temperature, and excellent temperature characteristics. Alternatively, optionally, the materials of the first passivation layer 21 and the second passivation layer 31 are both selected from silicon oxide, and the materials of the first doping layer 22 and the second doping layer 32 are both selected from doped polysilicon or doped microcrystalline silicon. That is, this back-contact solar cell is a TBC (Tunnel Oxide Back Contact) cell, and this back-contact solar cell also has advantages such as a high open-circuit voltage, a low process temperature, and excellent temperature characteristics. Alternatively, optionally, the materials of the first passivation layer 21 and the second passivation layer 31 are respectively selected from amorphous silicon or silicon oxide, and the materials of the first doping layer 22 and the second doping layer 32 are respectively selected from doped polysilicon or doped microcrystalline silicon. That is, for the materials of the first passivation layer 21 and the second passivation layer 31, one is selected from amorphous silicon and the other is selected from silicon oxide, and for the materials of the first doping layer 22 and the second doping layer 32, one is selected from doped polysilicon and the other is selected from doped microcrystalline silicon. This back-contact solar cell is an HTBC (Heterojunction Tunnel Oxide Back Contact) cell, and this back-contact solar cell also has advantages such as a high open-circuit voltage, a low process temperature, and excellent temperature characteristics.

[0070] As an embodiment of the present invention, the laser absorption protection layer 4 includes:

[0071] An insulating layer 41, disposed on the side of the second transmission layer 3 away from the silicon substrate 1 and exposing the electrode contact area of the second transmission layer 3;

[0072] A laser absorption layer, disposed on the side of the insulating layer 41 away from the silicon substrate 1 and exposing the electrode contact area of the second transmission layer 3.

[0073] In this embodiment, a second opening is formed in the laser absorption layer and the insulating layer 41 on the side of the second transmission layer 3 away from the silicon substrate 1, and the area of the second transmission layer 3 exposed by the second opening serves as the electrode contact area of the second electrode 8. The second electrode 8 contacts the second conductive layer 6 in this electrode contact area to collect the carriers in the second transmission layer 3.

[0074] In this embodiment, the laser absorption layer can adopt a single-layer, double-layer or more-layer structure. Among them, the insulating dielectric layer separates the laser absorption layer from the second transmission layer 3 to further protect the second transmission layer 3.

[0075] As an embodiment of the present utility model, the insulating groove 61 at least partially penetrates the laser absorption layer.

[0076] In this embodiment, the insulating groove 61 may only partially penetrate the laser absorption layer or may completely penetrate the laser absorption layer. That is to say, the depth of the insulating groove 61 is at least greater than the thickness of the second conductive layer 6. Additionally, the insulating groove 61 may also at least partially penetrate the insulating layer 41. Preferably, the insulating groove 61 penetrates both the laser absorption layer and the insulating layer 41 simultaneously, that is, the depth of the insulating groove 61 is greater than the total thickness of the second conductive layer 6 and the laser absorption layer, so that the removal of the second conductive layer 6 in the area of the insulating groove 61 is more complete.

[0077] As an embodiment of the present utility model, the insulating layer 41 is one or at least two stacked layers of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon carbide layer.

[0078] In this embodiment, the insulating layer 41 may be one of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon carbide layer, or may be a stacked structure of at least two of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon carbide layer.

[0079] As an embodiment of the present utility model, the laser absorption layer is one or at least two stacked layers of an amorphous silicon layer, a nanocrystalline silicon layer, a microcrystalline silicon layer, and a polycrystalline silicon layer, which can achieve a good laser absorption effect.

[0080] In this embodiment, the laser absorption layer may be one of an amorphous silicon layer, a nanocrystalline silicon layer, a microcrystalline silicon layer, and a polycrystalline silicon layer, or may be a stacked structure of at least two of an amorphous silicon layer, a nanocrystalline silicon layer, a microcrystalline silicon layer, and a polycrystalline silicon layer.

[0081] As an embodiment of the present utility model, the laser absorption layer includes:

[0082] A first laser absorption layer 42, disposed on a side of the insulating layer 41 away from the silicon substrate 1 and exposing an electrode contact area;

[0083] A second laser absorption layer 43, disposed on a side of the first laser absorption layer 42 away from the silicon substrate 1 and exposing an electrode contact area.

[0084] In this embodiment, the laser absorption layer is configured to include the first laser absorption layer 42 and the second laser absorption layer 43. By simultaneously absorbing heat and expanding with the two laser absorption layers, the two laser absorption layers push the part of the second conductive layer 6 near the edge of the insulating groove 61 outward to form a warping portion 62, which can better prevent the residue of the second conductive layer 6 at the position of the insulating groove 61 from adhering to the inside of the insulating groove 61, thereby further improving the production yield of the battery.

[0085] As an embodiment of the present utility model, the first laser absorption layer 42 is an intrinsic amorphous silicon layer, and the second laser absorption layer 43 is a doped amorphous silicon layer.

[0086] In this embodiment, the stacked structure formed by the intrinsic amorphous silicon layer and the doped amorphous silicon layer can further improve the back passivation effect of the back contact solar cell and improve the cell efficiency. Moreover, by cleverly using the intrinsic amorphous silicon layer as the first laser absorption layer 42 and the doped amorphous silicon layer as the second laser absorption layer 43, there is no need to separately set a laser absorption layer, realizing the passivation effect and laser absorption function of the intrinsic amorphous silicon layer and the doped amorphous silicon layer, which can reduce the production cost; when laser etching to form the insulating groove 61, the intrinsic amorphous silicon layer and the doped amorphous silicon layer are used to simultaneously push up the edge part of the second conductive layer 6 near the notch of the insulating groove 61 to form a warped part 62, avoiding the residue of the second conductive layer 6 at the position of the insulating groove 61 from adhering to the inside of the insulating groove 61, thereby further improving the production yield of the cell.

[0087] As another embodiment of the present utility model, the first laser absorption layer 42 is an intrinsic amorphous silicon layer, and the second laser absorption layer 43 is a doped amorphous silicon layer; the laser absorption layer may further include a third laser absorption layer disposed on the second laser absorption layer 43.

[0088] In this embodiment, while using the intrinsic amorphous silicon layer and the doped amorphous silicon layer as the second laser absorption layer 43, by adding a third laser absorption layer, the laser absorption effect of the laser absorption layer can be further improved, which is beneficial to improving the effect of the laser absorption layer in pushing up the part of the second conductive layer 6 near the insulating groove 61 to form a warped part 62. Among them, the third laser absorption layer can be one or a stack of a silicon carbide layer and a silicon nitride layer.

[0089] Please refer to again Figure 2 , as an embodiment of the present utility model, the height H of the warped part 62 is 0.2 to 2 micrometers. Wherein, the height H of the warped part 62 is the vertical distance from the top of the warped part 62 to the outer surface of the second conductive layer 6.

[0090] In this embodiment, the warped part 62 is distributed along the edge of the insulating groove 61, the height H of the warped part 62 is set uniformly or non-uniformly, and the height H of the warped part 62 is within the range of 0.2 to 2 micrometers, so as to ensure as much as possible that the edge part of the second conductive layer 6 near the insulating groove 61 is pushed up to form a warped part 62, and the warped part 62 formed at the edge of the insulating groove 61 can effectively prevent damage to the second conductive layer 6 and the silicon substrate 1 during the subsequent wet cleaning process, which can further improve the production yield of the cell.

[0091] As an embodiment of the present utility model, the included angle B between the warped part 62 and the side of the second conductive layer 6 close to the silicon substrate 1 is 15 to 150°.

[0092] In this embodiment, the warping portions 62 are distributed along the notch edge of the insulating groove 61. The angle B between the warping portions 62 and the surface of the second conductive layer 6 close to the silicon substrate 1 is in the range of 15 to 150°, ensuring that the edge portion of the second conductive layer 6 close to the insulating groove 61 warps outwards as much as possible to form the warping portions 62, and facilitating the warping portions 62 to prevent damage to the second conductive layer 6 and the silicon substrate 1 during the subsequent wet cleaning process.

[0093] As a preferred embodiment of the present utility model, the angle B between the warping portions 62 and the surface of the second conductive layer 6 close to the silicon substrate 1 is 90 to 150°.

[0094] In this embodiment, when the angle B between the warping portions 62 and the surface of the second conductive layer 6 close to the silicon substrate 1 is in the range of 90 to 150°, it can ensure that the edge portion of the second conductive layer 6 close to the insulating groove 61 warps outwards as much as possible, and enables the warping portions 62 to have a good effect of preventing damage to the second conductive layer 6 and the silicon substrate 1 during the subsequent wet cleaning process.

[0095] As an embodiment of the present utility model, the total thickness of the laser absorption layer is 5 to 50 nanometers, which can better ensure the warping degree of the warping portions 62.

[0096] Among them, when the laser absorption layer is a single layer, the total thickness of the laser absorption layer is 5 to 50 nanometers; when the laser absorption layer includes the first laser absorption layer 42 and the second laser absorption layer 43, the total thickness of the first laser absorption layer 42 and the second laser absorption layer 43 is 5 to 50 nanometers. The total thickness of the laser absorption layer being 5 to 50 nanometers is conducive to the laser absorption layer pushing the edge portion of the second conductive layer 6 located at the edge of the insulating groove 61 outwards when laser etching to form the insulating groove 61.

[0097] As an embodiment of the present utility model, the thickness of the second conductive layer 6 is 40 to 150 micrometers, which is conducive to the curling deformation of the second conductive layer 6 and is conducive to the edge portion of the second conductive layer 6 close to the insulating groove 61 being pushed outwards by the laser absorption layer to form curling to form the warping portions 62 when being laser etched.

[0098] As an embodiment of the present utility model, the second conductive layer 5 and / or the second conductive layer 6 is a transparent conductive metal oxide.

[0099] Among them, the materials of the second conductive layer 5 and the second conductive layer 6 can be the same or different. Preferably, the materials of the second conductive layer 5 and the second conductive layer 6 are the same, which is convenient for one-time processing and preparation of the second conductive layer 5 and the second conductive layer 6.

[0100] As an embodiment of the present utility model, both the second conductive layer 5 and the second conductive layer 6 are one or at least two laminations of ITO film, AZO film, and IZO film.

[0101] As an embodiment of the present utility model, the back contact solar cell further includes:

[0102] A front passivation layer 9 provided on the light-facing surface 12;

[0103] An antireflection film layer 10 provided on the side of the front passivation layer 9 away from the silicon substrate.

[0104] In this embodiment, by providing the front passivation layer 9 on the light-facing surface 12 of the silicon substrate 1, the front passivation effect is improved, which is beneficial to improving the battery efficiency; at the same time, the antireflection film layer 10 is used to reduce the sunlight reflectivity of the back contact solar cell, which is beneficial to further improving the battery efficiency.

[0105] As an embodiment of the present utility model, the front passivation layer 9 is an intrinsic amorphous silicon layer or an Al2O3 layer, and the second antireflection layer 10 is a SiN x layer. Of course, the materials of the front passivation layer 9 and the second antireflection layer 10 are not limited to this.

[0106] The embodiment of the present invention also provides a battery module, which includes the back contact solar cell of the above embodiment. It should be noted that this battery module has the same or similar beneficial effects as the back contact solar cell, and the relevant parts between the two can be referred to each other. To avoid repetition, it will not be elaborated here.

[0107] The embodiment of the present invention also provides a photovoltaic system, which includes the battery module of the above embodiment. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back contact solar cell, and the relevant parts between the two can be referred to each other. To avoid repetition, it will not be elaborated here.

[0108] In the back contact solar cell provided by the embodiment of the present utility model, a laser absorption layer is provided on the side of the second transmission layer 3 away from the backlight surface, and the second conductive layer 6 is provided on the side of the laser absorption layer away from the backlight surface. When forming the insulating groove 61 during the laser etching process of the second conductive layer 6, due to the heat absorption and expansion of the laser absorption layer, the laser absorption layer pushes the edge part of the second conductive layer 6 close to the notch of the insulating groove 61 outward to form a warping part 62, avoiding the residue of the second conductive layer 6 at the position of the insulating groove 61 from adhering to the inside of the insulating groove 61 and connecting with the first conductive layer 5 to form a leakage path, thereby improving the battery production yield; moreover, the warping part 62 formed at the notch edge of the insulating groove 61 can block the damage to the second conductive layer 6 and the silicon substrate 1 during the wet cleaning process, which can further improve the battery production yield.

[0109] The above are only the preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A back-contact solar cell, characterized in that, Comprising: A silicon substrate, the silicon substrate including a backlight surface, and a first region and a second region being provided on the backlight surface of the silicon substrate; A first transmission layer provided in the first region; A second transmission layer provided in the second region, the doping type of the second transmission layer being different from that of the first transmission layer; A laser absorption protection layer provided on a side of the second transmission layer away from the backlight surface and exposing an electrode contact region of the second transmission layer; A first conductive layer provided on a side of the first transmission layer away from the backlight surface; A second conductive layer provided on a side of the laser absorption protection layer away from the backlight surface, the second conductive layer covering the laser absorption protection layer and the electrode contact region of the second transmission layer, an insulating groove being provided in a region of the second conductive layer close to the first conductive layer, and a warping portion warping from the inner side to the outer side of the insulating groove being formed at the notch edge of the insulating groove of the second conductive layer.

2. The back-contact solar cell according to claim 1, characterized in that, Further comprising: A first electrode provided in the first region and in contact with the first conductive layer; A second electrode provided in the second region and in contact with the second conductive layer corresponding to the electrode contact region, and the insulating groove being located between the first electrode and the second electrode.

3. The back-contact solar cell according to claim 1, characterized in that, The first transmission layer includes a first passivation layer and a first doped layer stacked in sequence on the backlight surface, and the first conductive layer is provided on a side of the first doped layer away from the silicon substrate; The second transmission layer includes a second passivation layer and a second doped layer stacked in sequence on the backlight surface, the doping types of the first doped layer and the second doped layer being different, and the laser absorption protection layer is provided on a side of the second doped layer away from the silicon substrate.

4. The back contact solar cell according to claim 3, characterized in that, The first passivation layer and the second passivation layer are both amorphous silicon; the first doped layer and the second doped layer are both doped amorphous silicon or doped microcrystalline silicon; Or, the first passivation layer and the second passivation layer are both silicon oxide; The first doped layer and the second doped layer are doped polysilicon or doped microcrystalline silicon; Or, the first passivation layer and the second passivation layer are amorphous silicon and silicon oxide respectively, and the first doped layer and the second doped layer are doped polysilicon and doped microcrystalline silicon respectively.

5. The back contact solar cell according to claim 1, wherein The laser absorption protection layer includes: An insulating layer provided on a side of the second transmission layer away from the silicon substrate and exposing the electrode contact region of the second transmission layer; A laser absorption layer provided on a side of the insulating layer away from the silicon substrate and exposing the electrode contact region of the second transmission layer.

6. The back-contact solar cell according to claim 5, wherein The insulating layer is one or a stack of at least two of a silicon nitride layer, a silicon oxynitride layer, a silicon oxide layer, and a silicon carbide layer.

7. The back-contact solar cell according to claim 5, characterized in that, The laser absorption layer is one or a stack of at least two of an amorphous silicon layer, a nanocrystalline silicon layer, a microcrystalline silicon layer, and a polysilicon layer.

8. The back contact solar cell according to claim 5, characterized in that, The laser absorption layer includes: A first laser absorption layer provided on a side of the insulating layer away from the silicon substrate and exposing the electrode contact region; A second laser absorption layer provided on a side of the first laser absorption layer away from the silicon substrate and exposing the electrode contact region.

9. The back-contact solar cell according to claim 8, wherein The first laser absorption layer is an intrinsic amorphous silicon layer, and the second laser absorption layer is a doped amorphous silicon layer.

10. The back-contact solar cell according to claim 5, characterized in that, The insulating groove at least partially penetrates through the laser absorption layer.

11. The back-contact solar cell according to claim 5, characterized in that, The total thickness of the laser absorption layer is 5 to 50 nanometers.

12. The back contact solar cell according to claim 1, characterized in that, The thickness of the second conductive layer is 40 to 150 micrometers.

13. The back-contact solar cell according to claim 1, characterized in that, The height of the warping portion is 0.2 to 2 micrometers.

14. The back contact solar cell according to claim 1, characterized in that, The angle B between the warping portion and the side of the second conductive layer close to the silicon substrate is 15 to 150°.

15. The back contact solar cell according to claim 1, characterized in that, The angle B between the warping portion and the side of the second conductive layer close to the silicon substrate is 90 to 150°.

16. The back-contact solar cell according to claim 1, wherein, The silicon substrate further includes a light-facing surface disposed opposite to the backlight surface, and the back-contact solar cell further includes: A front passivation layer disposed on the light-facing surface; An antireflection film layer disposed on a side of the front passivation layer away from the silicon substrate.

17. A battery assembly, characterized in that, Comprising the back-contact solar cell according to any one of claims 1 to 16.

18. A photovoltaic system, characterized in that, Comprising the battery assembly according to claim 17.

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