Solar cell and photovoltaic module

Abstract

The utility model provides a solar cell and a photovoltaic assembly, and relates to the field of photovoltaic technology. The solar cell includes a silicon substrate; the functional layer comprises a part arranged on the first side of the silicon substrate and a part arranged on the second side of the silicon substrate; the functional layer comprises a doping layer and a surface passivation layer which are stacked in sequence; the electrode structures are positioned on the first side and the second side, and each electrode structure comprises a contact electrode which penetrates through the opening of the surface passivation layer and is in contact with the doping layer, and a transmission electrode which is positioned on the contact electrode and is electrically connected with the contact electrode; the contact electrode and the transmission electrode on the contact electrode extend along the same direction; the transmission electrodes are used for interconnection between two adjacent solar cells; the contact electrodes located on the first side of the silicon substrate and the contact electrodes located on the second side of the silicon substrate are distributed in a staggered mode in the thickness direction of the silicon substrate, the subfissure and cracking probability can be reduced, the current collection effect is improved, conductive interconnection pieces do not need to be independently arranged, the technology is simple, and cost is low.

Description

Technical Field

[0001] The utility model relates to the technical field of photovoltaics, in particular to a solar cell and a photovoltaic component. Background Art

[0002] The electrode structures on either side of the silicon substrate in a solar cell are used to contact the doped layer to collect and conduct current. A surface passivation layer is typically placed between the doped layer and the electrode structure to enhance passivation. The electrode structures typically pass through openings in the surface passivation layer to effectively contact the doped layer.

[0003] Currently, in existing solar cells, the electrode structures located on both sides of the silicon substrate are aligned and distributed along the thickness direction of the silicon substrate. This requires that openings be provided at aligned positions of the surface passivation layers on both sides.

[0004] However, the process of setting the openings will introduce thermal influences to the existing structures in the solar cell. Setting openings at the passivation alignment positions on both sides will introduce more thermal influences at relatively concentrated positions, making the solar cell prone to hidden cracks and fragments. Utility Model Content

[0005] The utility model provides a solar cell and a photovoltaic component, aiming to solve the problems of high risk of hidden cracks and fragments in existing solar cells.

[0006] In a first aspect, the present invention provides a solar cell comprising:

[0007] A silicon substrate; the silicon substrate comprising a first side and a second side opposite to each other;

[0008] A functional layer, wherein the functional layer includes a portion disposed on a first side of the silicon substrate and a portion disposed on a second side of the silicon substrate; the functional layer includes: a doping layer and a surface passivation layer stacked in sequence; the doping layer located on the first side of the silicon substrate and the doping layer located on the second side of the silicon substrate have different doping types;

[0009] an electrode structure located on the first side and the second side, the electrode structure comprising: a contact electrode passing through the opening of the surface passivation layer and contacting the doped layer, and a transmission electrode located on the contact electrode and electrically connected to the contact electrode; the contact electrode and the transmission electrode located thereon extend in the same direction; the transmission electrode is used for interconnecting two adjacent solar cells;

[0010] Along the thickness direction of the silicon substrate, the contact electrodes located on the first side of the silicon substrate and the contact electrodes located on the second side of the silicon substrate are staggered.

[0011] In this application, along the thickness direction of the silicon substrate, the contact electrodes on the first side of the silicon substrate and the contact electrodes on the second side of the silicon substrate are not aligned. Consequently, openings are provided at staggered positions in the surface passivation layers on both sides, rather than at aligned positions in the surface passivation layers on both sides. This results in a relatively dispersed distribution of thermal effects within the solar cell, avoiding stress concentration and significantly reducing hidden cracks and fragmentation. Furthermore, the transmission electrodes can also electrically interconnect adjacent solar cells when multiple solar cells form a cell string, eliminating the need for separate conductive interconnects. This simplifies the process and reduces costs.

[0012] Along the thickness of the silicon substrate, the contact electrodes on the first side of the silicon substrate and the contact electrodes on the second side of the silicon substrate are staggered, with a staggered distance d1 ranging from 40 μm to 1000 μm. This moderate staggered distance ensures a moderate distribution density of contact electrodes, facilitating current collection and conduction. This achieves a good balance between reducing hidden cracks and debris and ensuring current collection and conduction.

[0013] Optionally, the d1 is greater than or equal to the thickness of the silicon substrate.

[0014] Optionally, the distance between the geometric centers of two adjacent contact electrodes located on the same side of the silicon substrate is d2, and d2 is greater than or equal to the thickness d3 of the silicon substrate and less than or equal to 2000 um.

[0015] Optionally, the distance between the geometric centers of two adjacent contact electrodes located on the same side of the silicon substrate is d2, and the width d4 of one contact electrode is less than or equal to d2; d4 is parallel to the direction of d2 and is perpendicular to the direction of the thickness of the silicon substrate.

[0016] Optionally, a width d4 of the contact electrode is 15 um to 100 um; the direction of d4 is perpendicular to the extension direction of the transmission electrode and perpendicular to the direction of the thickness of the silicon substrate.

[0017] Optionally, at least one of the contact electrodes is a discontinuous structure; the discontinuous structure includes a plurality of sub-contact electrodes arranged at intervals in the same direction; and at least one of the transmission electrodes is electrically connected to a plurality of the sub-contact electrodes at the same time.

[0018] Optionally, a distance between geometric centers of two adjacent contact electrodes located on the same side of the silicon substrate is d2; a thickness of the silicon substrate is d3; a distance between two adjacent sub-contact electrodes electrically connected by one of the transmission electrodes in the same direction is d5; a width of one of the contact electrodes is d4; the d4 is parallel to the direction in which the d2 is located, and both are perpendicular to the direction in which the thickness of the silicon substrate is located; the d5 is perpendicular to both the direction in which the d4 is located and the direction in which the thickness of the silicon substrate is located.

[0019] The d5 is greater than the d4 and less than the d3.

[0020] Optionally, a shape of a section of the transmission electrode parallel to the thickness direction of the silicon substrate is one of Gaussian distribution type, triangle, rectangle, flat type, circle, ellipse, and rectangle with chamfer.

[0021] Optionally, the solar cell further comprises: a conductive material located between the contact electrode and the transmission electrode.

[0022] Optionally, the opening further has a gap; the solar cell further comprises: a filling material filled in the gap.

[0023] Optionally, a gap is between the contact electrode and an inner wall of the opening of the surface passivation layer, and the filling material is a conductive material or an insulating material.

[0024] Optionally, a shape of the doped layer is adapted to a shape of the contact electrode located on the same side of the silicon substrate as the doped layer.

[0025] Optionally, the functional layer further comprises: an interface surface passivation layer located between the silicon substrate and the doped layer.

[0026] In a second aspect, the utility model provides a photovoltaic module, comprising: a plurality of any preceding solar cell; adjacent two solar cells are interconnected through the transmission electrode.

[0027] Optionally, at least two adjacent solar cells partially overlap.

[0028] The solar cell and the photovoltaic module have the same or similar beneficial effects, and details are not repeated here to avoid repetition. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0030] Figure 1 A schematic structural diagram of a solar cell in an embodiment of the present utility model is shown;

[0031] Figure 2 A perspective schematic diagram showing a first electrode structure and a second electrode structure of a solar cell in an embodiment of the present utility model is shown;

[0032] Figure 3 A perspective schematic diagram showing a first electrode structure and a second electrode structure of another solar cell in an embodiment of the present utility model is shown;

[0033] Figure 4 A schematic diagram of the overlapping area of ​​two solar cells at the ends in an embodiment of the present invention is shown.

[0034] Description of the accompanying figures:

[0035] 1-silicon substrate, 2-doping layer, 3-surface passivation layer, 41-contact electrode, 42-transmission electrode, 5-heat-affected zone, 411-sub-contact electrode DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0037] The utility model provides a solar cell, referring to Figure 1 The solar cell may include: a silicon substrate 1, a functional layer, and an electrode structure. The silicon substrate 1 includes a first side and a second side opposite to each other. Here, one of the first side and the second side is a light-facing side, and the other is a backlight side. During normal operation of the solar cell, the side that mainly receives light is the light-facing side, and the backlight side is opposite to the light-facing side. For example, Figure 1 In the embodiment, the upper and lower sides of the silicon substrate 1 are the first side and the second side, respectively. The silicon substrate 1 can be a p-type silicon substrate, an n-type silicon substrate, or a silicon substrate with a conductivity type close to that of an intrinsic conductivity type. The crystal type can be single crystal or polycrystalline.

[0038] The functional layer includes a portion disposed on the first side of the silicon substrate 1 and a portion disposed on the second side of the silicon substrate 1. The functional layer may include: a doping layer 2 and a surface passivation layer 3 stacked in sequence, with the doping layer 2 being closer to the silicon substrate 1. The doping type of the doping layer located on the first side of the silicon substrate 1 is different from the doping type of the doping layer located on the second side of the silicon substrate 1, one of which is n-type doping and the other is p-type doping. The doping layer 2 may be composed of one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon. The p-type doping layer is generally doped with Group III elements. The n-type doping layer is generally doped with Group V elements or Group VI elements.

[0039] The functional layer here can achieve functions such as current conduction and passivation anti-reflection. The surface passivation layer 3 can be composed of one or more layers, or can be composed of different materials in different regions. The material of the surface passivation layer 3 can include one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. The surface passivation layer 3 is provided with an opening.

[0040] The electrode structure is located on the first side and the second side of the silicon substrate 1 and includes a front electrode structure and a back electrode structure. The electrode structure includes a contact electrode 41 located within the opening and in contact with the doped layer 2, and a transmission electrode 42 located on the contact electrode 41. The contact electrode 41 and the transmission electrode 42 form an electrical connection, thereby enabling current collection and conduction from the doped layer 2 to the contact electrode 41 and then to the transmission electrode 42. Both the contact electrode 41 and the transmission electrode 42 can be made of metals (e.g., Ag, Cu, Al, Ni, Au, Zn, Sn, Pb, etc.), metal oxides (e.g., various TCOs, such as ITO, AZO, IWO, etc.), metal nitrides (e.g., TiN), metal carbides (e.g., TiC), or metal sulfides, as well as other conductive connecting materials (e.g., graphene), or various combinations of the above materials. Preferred transmission electrodes are made of base metals, such as Al, Cu, and other inexpensive metals based on aluminum and / or copper.

[0041] Figure 1 The direction indicated by L1 refers to the thickness direction of the silicon substrate 1. Along the thickness direction L1 of the silicon substrate 1, the contact electrode 41 located on the first side of the silicon substrate 1 and the contact electrode 41 located on the second side of the silicon substrate 1 are staggered. Along the thickness direction L1 of the silicon substrate 1, the contact electrode 41 located on the first side of the silicon substrate 1 and the contact electrode 41 located on the second side of the silicon substrate 1 are not aligned. Therefore, openings are set at staggered positions of the surface passivation layers 3 on both sides, and openings are not set at aligned positions of the surface passivation layers on both sides. The heat-affected zone 5 is relatively more dispersed in the solar cell, which avoids stress concentration and can significantly reduce hidden cracks and fragments.

[0042] Reference Figure 2 and Figure 3 , L2 can be perpendicular to the thickness direction L1 of the silicon substrate 1 and perpendicular to the extension direction L3 of the transmission electrode 42. The contact electrode and the transmission electrode located above it extend in the same direction L3. The transmission electrode 42 can also complete the electrical interconnection between adjacent solar cells when multiple solar cells are formed into a cell string, eliminating the need to separately provide conductive interconnects, such as traditional solder ribbons, on the entire surface of the solar cells. This also simplifies the process and reduces costs.

[0043] Optionally, the offset distance d1 is 40um to 1000um, and the offset distance d1 is not too large, so that the distribution density of the contact electrodes 41 is not too small, which is conducive to current collection and conduction, that is, a good balance is achieved in reducing hidden cracks and fragments, and current collection and conduction.

[0044] For example, along the thickness direction L1 of the silicon substrate 1, the contact electrode 41 located on the first side of the silicon substrate 1 and the contact electrode 41 located on the second side of the silicon substrate 1 are staggered, and the staggered distance d1 can be 40um, 50um, 80um, 100um, 150um, 200um, 250um, 300um, 400um, 500um, 520um, 550um, 600um, 700um, 800um, 900um, or 1000um.

[0045] Optionally, along the thickness direction L1 of the silicon substrate 1, the contact electrodes 41 on the first side of the silicon substrate 1 and the contact electrodes 41 on the second side of the silicon substrate 1 are staggered, and the staggered distance d1 is greater than the thickness d3 of the silicon substrate 1. The thickness d3 of the silicon substrate 1 is the minimum distance between the contact electrodes 41 on the first side of the silicon substrate 1 and the contact electrodes 41 on the second side of the silicon substrate 1 when the contact electrodes 41 on the first side and the contact electrodes 41 on the second side of the silicon substrate 1 are aligned. The staggered distance d1 is greater than the thickness d3 of the silicon substrate 1. A larger staggered distance d1 disperses stress points, further avoiding thermal stress concentration, further reducing cracks and fragmentation, thereby reducing the probability of cell damage, thereby reducing damage to the entire photovoltaic device or photovoltaic system, and reducing safety risks. For example, the thickness d3 of the silicon substrate 1 can be 60 μm to 200 μm, and further, the staggered distance d1 can be greater than or equal to 60 μm. It should be noted that the combined thickness of the surface passivation layer 3 and the doping layer 2 is typically relatively small, for example, less than 2 μm. Therefore, the combined thickness of the surface passivation layer 3 and the doping layer 2 can be included in the thickness of the silicon substrate 1. Here, d1 is parallel to the direction indicated by L2, and L2 can be perpendicular to L1, the thickness direction of the silicon substrate 1, and perpendicular to the extension direction of the transmission electrode 42.

[0046] Optional, see Figure 1As shown, the distance d2 between the geometric centers of two adjacent contact electrodes 41 located on the same side of the silicon substrate 1 is greater than or equal to the thickness d3 of the silicon substrate 1 and less than or equal to 2000 μm. The thickness d3 of the silicon substrate 1 is the minimum distance between the contact electrodes 41 on the first side of the silicon substrate 1 and the contact electrodes 41 on the second side of the silicon substrate 1 when the contact electrodes 41 on the two sides are aligned. The distance d2 between the geometric centers of two adjacent contact electrodes 41 on the same side of the silicon substrate 1 is greater than or equal to the thickness d3 of the silicon substrate 1. The larger d2 is because, on the one hand, solid surfaces also have solid specific surface energy or surface tension, so the distance d2 between two adjacent contact electrodes 41 on the same side cannot be too close. On the other hand, stress points are dispersed on the same side of the silicon substrate 1, further avoiding thermal stress concentration, further reducing hidden cracks and fragments, thereby reducing the probability of cell damage, thereby reducing damage to the entire photovoltaic device or photovoltaic system, and reducing safety risks. Moreover, the distance d2 between the geometric centers of two adjacent contact electrodes 41 located on the same side of the silicon substrate 1 is not too large, so that the distribution density of the contact electrodes 41 is not too small, which is conducive to the collection and conduction of current, that is, a good balance is achieved between reducing hidden cracks and fragments, and collecting and conducting current. For example, the thickness d3 of the silicon substrate 1 can be 60um to 200um, and furthermore, the distance d2 between the geometric centers of two adjacent contact electrodes 41 located on the same side of the silicon substrate 1 can be greater than or equal to 60um. It should be noted that the total thickness of the surface passivation layer 3 and the doping layer 2 is generally small, for example, within 2um, so the total thickness of the surface passivation layer 3 and the doping layer 2 can be counted as part of the thickness of the silicon substrate 1.

[0047] For example, d2 can be 2000um, 1900um, 1800um, 1500um, 1450um, 1200um, 900um, 1300um, 1000um, 550um, 600um, 700um, 800um, 900um, 500um, 300um, or the thickness d3 of the silicon substrate 1.

[0048] Optionally, the width d4 of a contact electrode 41 is less than or equal to the distance d2 between the geometric centers of two adjacent contact electrodes 41 located on the same side of the silicon substrate 1. The width d4 is parallel to the direction of d2 and perpendicular to the direction L1 of the thickness of the silicon substrate 1. d2 can reflect the distribution density of the contact electrodes 41 on the same side of the silicon substrate 1. The width d4 of a contact electrode 41 can reflect the number of current collection channels. The distribution density and the width d4 of a contact electrode 41 are both closely related to the current collection effect and thermal stress. By establishing this correlation between the two, a good balance can be achieved between the distribution density of the contact electrodes 41, the current collection effect, and the thermal stress dispersion, which helps to improve the current collection effect and reduce hidden cracks and fragments.

[0049] Optionally, the width d4 of a contact electrode 41 is 15 μm to 100 μm. The width d4 of a contact electrode 41 can reflect the number of current collection channels and the thermal stress situation. Within this range, d4 not only improves current collection but also effectively disperses thermal stress, reducing the risk of hidden cracks and fragmentation. More specifically, d4 should not be too small to affect current collection, nor too large to introduce excessive thermal stress in relatively concentrated locations.

[0050] For example, the width d4 of one contact electrode 41 may be 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, 55um, 60um, 65um, 70um, 75um, 80um, 85um, 95um, 90um, or 100um.

[0051] Figure 2 It is a perspective schematic diagram showing both electrode structures facing toward the direction close to the silicon substrate. Figure 3 This is another perspective diagram showing both electrode structures facing the direction close to the silicon substrate. The extension direction of the transmission electrode 42 is L3, which is perpendicular to the direction L1 of the thickness of the silicon substrate 1 and also perpendicular to the aforementioned L2. Figure 2 and Figure 3 , at least one contact electrode 41 is a discontinuous structure; the discontinuous structure includes a plurality of sub-contact electrodes 411 spaced apart in the same direction indicated by the extension direction L3 of the transmission electrode 42, and one transmission electrode 42 is electrically connected to at least two sub-contact electrodes 411, for example, Figure 2 , the plurality of sub-contact electrodes 411 located within a transmission electrode 42 are sub-contact electrodes 411 electrically connected to the transmission electrode 42. For example, Figure 2In the example, multiple sub-contact electrodes 411 distributed along the extension direction L3 of the transmission electrode 42 form a contact electrode. In the extension direction L3 of the transmission electrode 42, the distance between two adjacent sub-contact electrodes 411 electrically connected to one transmission electrode 42 is d5, which is greater than d4 and less than d3. The direction L3 of d5 is perpendicular to the direction L2 of d4 and the direction L1 of the thickness of the silicon substrate 1. Both d4 and d5 are related to the electrical connection performance of the transmission electrode 42. By limiting d5 to be greater than d4, d5 is not too small, which can reduce costs. By limiting d5 to be less than d3, d5 is not too large, which can ensure current collection performance. More specifically, under normal circumstances, the conductive performance of the sub-contact electrode 411 has a greater impact on current collection. Therefore, it may be necessary to ensure that the sub-contact electrode 411 has good conductive performance, which may result in relatively high costs. By limiting d5 to a small value, that is, in the direction indicated by L3, the density of the sub-contact electrodes 411 connected to the same transmission electrode 42 is appropriate, not too dense, and can appropriately reduce costs. At the same time, compared with the transmission electrode 42, the distribution area of ​​the contact electrode 41 is more localized, which can effectively reduce surface recombination and reduce the setting cost of the contact electrode 41. Moreover, the multiple sub-contact electrodes 411 arranged at intervals in the same direction indicated by the extension direction L3 of the transmission electrode 42 can exist as partial positioning of the transmission electrode, which can improve the setting accuracy of the transmission electrode.

[0052] For example, refer to Figure 3 The transmission electrode 42 shown on the far left is connected to a contact electrode 41 comprising two rows of sub-contact electrodes 411 spaced apart in the extension direction L3 of the transmission electrode 42. Consequently, for each contact electrode 41, the opening size in the surface passivation layer corresponding to each contact electrode 41 is relatively small. This can help disperse thermal stress during the opening process, potentially reducing the depth of thermal stress distribution and improving carrier collection capabilities. It should be noted that there is no limit to the specific number of rows of contact electrodes 41 to which a transmission electrode 42 is electrically connected. For example, a transmission electrode 42 can be electrically connected to two, three, four, five, or six rows of contact electrodes 41. The rows are parallel to the extension direction L3 of the transmission electrode 42.

[0053] For example, refer to Figure 3The transmission electrodes 42 shown in the second, third, and fourth electrodes from left to right are electrically connected to one contact electrode. Each contact electrode 41 has a discontinuous structure, which includes a plurality of sub-contact electrodes 411 spaced apart in the same direction indicated by the extension direction L3 of the transmission electrode 42. The sub-contact electrodes 411 in the plurality of contact electrodes are at least partially collinear and distributed in a spaced-apart point-like manner. Compared with the transmission electrodes 42, the distribution area of ​​the contact electrodes 41 is more localized, which can effectively reduce surface recombination and reduce the setting cost of the contact electrodes 41. Moreover, the collinear portion of the contact electrodes can serve as a partial positioning portion of the transmission electrode, which can improve the setting accuracy of the transmission electrode.

[0054] For example, refer to Figure 3 The transmission electrodes 42 shown in numbers 5 and 7 from left to right are electrically connected to one contact electrode 41. Each contact electrode 41 has a discontinuous structure, which includes a plurality of sub-contact electrodes 411 arranged at intervals in the same direction indicated by the extension direction L3 of the transmission electrode 42. The distribution area of ​​the contact electrode 41 is more localized, which can effectively reduce surface recombination and reduce the setting cost of the contact electrode 41. Moreover, the collinear portion of the contact electrode can be used as a partial positioning portion of the transmission electrode, which can improve the setting accuracy of the transmission electrode.

[0055] It should be noted that Figure 3 The size of the sub-contact electrodes 411 shown in the 5th and 7th positions from left to right in the direction shown by L3 is larger than Figure 3 The dimensions of the second, third, and fourth sub-contact electrodes 411 from left to right are in the direction indicated by L3. Figure 3 The size of the sub-contact electrode 411 shown on the far left is smaller than Figure 3 The sizes of the second, third, and fourth sub-contact electrodes 411 from left to right. Figure 3 The contact electrode 41 shown on the far left has a size smaller than that in the L2 direction. Figure 3 The dimensions of the contact electrodes 41 shown second, third, and fourth from left to right are in the L2 direction.

[0056] Optionally, the cross-sectional shape of the transmission electrode 42 parallel to the thickness direction L1 of the silicon substrate 1 is one of a Gaussian distribution, a triangle, a rectangle, a flat shape, a circle, an ellipse, or a rectangle with chamfered corners. The cross-sectional shape of the transmission electrode 42 parallel to the thickness direction L1 of the silicon substrate 1 can be flexible and diverse. The cross-sectional shape of the transmission electrode 42 parallel to the thickness direction L1 of the silicon substrate 1 refers to the shape of the contour line of the cross-sectional shape of the transmission electrode 42 parallel to the thickness direction L1 of the silicon substrate 1. The Gaussian distribution here means that the contour line of the cross-sectional shape of the transmission electrode 42 parallel to the thickness direction L1 of the silicon substrate 1 has a portion similar to a Gaussian distribution curve.

[0057] Optionally, the solar cell can further comprise: a conductive material between the contact electrode 41 and the transport electrode 42, which can increase the conductivity between the contact electrode 41 and the transport electrode 42, and the conductive material can be conductive glue, tin paste, etc., which can fill the gap between the contact electrode 41 and the transport electrode 42, and further improve the electrical connection.

[0058] Optionally, the opening of the surface passivation layer 3 also has a gap, which can be the gap between the contact electrode and the surface passivation layer, etc., and the solar cell can further comprise: a filling material filled in the gap, which can reduce the cavity in the opening and improve the mechanical strength and reliability of the solar cell, etc., through the filling of the filling material.

[0059] Optionally, there is a gap between the inner wall of the opening of the contact electrode and the surface passivation layer, and the filling material can be a conductive material or an insulating material, and in the case of the filling material being a conductive material, it is equivalent to increasing the contact area of the contact electrode, and in the case of the filling material being a conductive material, it can increase the contact effect of the contact electrode and the doped layer, reduce the cavity in the opening, and improve the mechanical strength and reliability of the solar cell, etc. The conductive material can be conductive glue and tin paste, etc., and the insulating material can be an insulating material with certain adhesion, such as insulating glue, which further improves the connection strength of the surface passivation layer and the contact electrode. Alternatively, the insulating material can be a general insulating material or a flexible insulating material, etc., which is not limited in particular. The flexible insulating material can absorb part of the stress, etc., further reducing the risk of hidden cracks and fragments.

[0060] Optionally, the shape of the doped layer 2 can be adapted to the shape of the contact electrode 41 on the same side of the silicon substrate 1 as the doped layer 2, that is, the shape of the doped layer 2 can be similar or identical to the shape of the contact electrode 41 on the same side of the silicon substrate 1 as the doped layer 2, and the size of the two is approximately equal or equal, which can save the material of the doped layer and reduce the cost. Specifically, the main part of the current collection and conduction is the part of the doped layer that contacts the contact electrode, so appropriately reducing the size of the doped layer that does not contact the contact electrode has little effect on current collection and conduction and can appropriately reduce the cost.

[0061] Optionally, in the solar cell, the functional layer may further include: an interface passivation layer, located between the silicon substrate 1 and the doped layer 2, which can enhance the passivation effect between the silicon substrate 1 and the doped layer 2. It should be noted that the interface passivation layer here can be located on only one side or both sides of the first side and the second side of the silicon substrate. The interface passivation layer can be composed of one layer or multiple layers, or can be composed of different materials in different regions. The material of the interface passivation layer may include: one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon.

[0062] The following further explains a method for preparing a solar cell provided by the present application: a. Surface treatment of a silicon wafer to obtain a silicon substrate, and forming a doping layer on the silicon substrate. b. Complete the surface passivation step. Form a surface passivation layer and / or an anti-reflection film on the front side (light-facing side) and the back side (backlight side) of the structure obtained in a. The surface passivation and anti-reflection film on the front side can be composed of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. The surface passivation layer on the back side can be composed of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. The structure of the surface passivation layer can be a single layer or a multilayer. For example: first use the ALD (atomic layer deposition) method to prepare a layer of aluminum oxide passivation layer, and then use PECVD to form one or more layers of silicon nitride layer thereon. The preparation method of the surface passivation layer can be ALD, various CVD (such as PECVD, APCVD, LPCVD, MOCVD, etc.), various PVD (evaporation, sputtering), etc.

[0063] c. Performing a window opening process on the surface passivation layer, such as using a laser or other process to remove a portion of the surface passivation layer to form an opening.

[0064] d. Forming the electrode structure. After laser windowing, contact electrodes are formed using methods such as ALD, various CVD, PVD, chemical plating, and electroplating. The contact electrode formation process can include various steps such as patterning masking, annealing, sintering, plasticization, and transfer.

[0065] The present application may also not perform a window opening process on the surface passivation layer in advance, but directly print the electrode paste by printing, and then form a corrosion opening on the surface passivation layer through sintering, so that the sintered electrode is in contact with the doping layer, thereby completing the preparation of the contact electrode.

[0066] e. Forming the transmission electrode. The transmission electrode can be formed after the contact electrode is completed, or can be formed simultaneously with the contact electrode; the transmission electrode and the contact electrode can use the same material, such as Al or Ag, etc. The transmission electrode can also be a material different from the contact electrode, such as a copper wire and a soldering material located on the copper wire. The transmission electrode is used to directly complete the contact with the contact electrode when a plurality of cells form a cell string, and to complete the electrical interconnection of adjacent solar cells, thereby replacing the existing string welding process using a conventional soldering ribbon.

[0067] The application also provides a photovoltaic module, which can include a plurality of any one of the foregoing solar cells, and can further include an encapsulating film or the like located outside the solar cells, so as to expand the application scenarios of the solar cells. The transmission electrode is used to interconnect two adjacent solar cells, without the need to separately provide a conductive interconnecting member, such as a conventional soldering ribbon, on the surface of the entire solar cell. The process is simple and the cost is low.

[0068] Optionally, referring to Figure 4 which is a kind of electrical interconnection between adjacent solar cells in a photovoltaic module. In the photovoltaic module, at least two adjacent solar cells overlap at the end portion, and the electrical interconnection between adjacent solar cells is realized by the transmission electrode on the back surface of the previous solar cell and the transmission electrode on the front surface of the subsequent solar cell. The electrical connection between the transmission electrode on the back surface of the previous solar cell and the transmission electrode on the front surface of the subsequent solar cell can be realized by an additional conductive structure, such as a metal conductive layer, a circuit substrate, conductive glue, etc. In the present application, the solar cells are directly partially overlapped, which not only reduces the stress, but also reduces the mutual repulsion of the electrode structures of adjacent solar cells on the same straight line, thereby improving the yield of the photovoltaic module and reducing the stress.

[0069] It should be noted that in this document, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such a process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0070] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all within the protection of the present invention.

Claims

1. A solar cell, characterized in that: include: A silicon substrate; the silicon substrate comprising a first side and a second side opposite to each other; A functional layer, wherein the functional layer includes a portion disposed on a first side of the silicon substrate and a portion disposed on a second side of the silicon substrate; the functional layer includes: a doping layer and a surface passivation layer stacked in sequence; the doping layer located on the first side of the silicon substrate and the doping layer located on the second side of the silicon substrate have different doping types; an electrode structure comprising: a contact electrode passing through the opening of the surface passivation layer and contacting the doped layer, and a transmission electrode located on the contact electrode and electrically connected to the contact electrode; the contact electrode and the transmission electrode located thereon extend in the same direction; the transmission electrode is used for interconnecting two adjacent solar cells; Along the thickness direction of the silicon substrate, the contact electrodes located on the first side of the silicon substrate and the contact electrodes located on the second side of the silicon substrate are staggered. 2 . The solar cell according to claim 1 , wherein along the thickness direction of the silicon substrate, a misalignment distance d1 between the contact electrode located on the first side of the silicon substrate and the contact electrode located on the second side of the silicon substrate is 40 μm to 1000 μm.

3. The solar cell according to claim 2, wherein The d1 is greater than or equal to the thickness of the silicon substrate.

4. The solar cell according to claim 1, wherein The distance between the geometric centers of two adjacent contact electrodes located on the same side of the silicon substrate is d2, and d2 is greater than or equal to the thickness d3 of the silicon substrate and less than or equal to 2000 um.

5. The solar cell according to claim 1, wherein At least one of the contact electrodes is a discontinuous structure; the discontinuous structure includes a plurality of sub-contact electrodes arranged at intervals in the same direction; and at least one of the transmission electrodes is electrically connected to a plurality of the sub-contact electrodes at the same time.

6. The solar cell according to claim 1, wherein Also includes: A conductive material is located between the contact electrode and the transmission electrode.

7. The solar cell according to claim 1, wherein The opening further has a gap therein; and the solar cell further includes a filling material filled in the gap.

8. The solar cell according to claim 7, characterized in that There is a gap between the contact electrode and the inner wall of the opening of the surface passivation layer, and the filling material is a conductive material or an insulating material.

9. A photovoltaic module, characterized in that: include: The solar cell according to any one of claims 1 to 8; Two adjacent solar cells are interconnected via the transmission electrodes.

10. The photovoltaic module according to claim 9, characterized in that: At least two adjacent solar cells partially overlap.

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