Silicon heterojunction solar cell string and photovoltaic module

Abstract

The utility model relates to a silicon heterojunction solar cell string and a photovoltaic module. The silicon heterojunction solar cell string comprises a plurality of cell sheets, a plurality of first conductive members and a plurality of second conductive members. The N-type doping layers in the first battery pieces face the light receiving surfaces of the first battery pieces, the P-type doping layers in the second battery pieces face the light receiving surfaces of the second battery pieces, the multiple first battery pieces and the multiple second battery pieces are arranged in a staggered mode in the first direction, and the adjacent first battery pieces and second battery pieces are close to each other; the first conductive piece is connected with the backlight face of the previous battery piece and the backlight face of the next battery piece in the adjacent battery pieces in the first direction, and the second conductive piece is connected with the light receiving face of the next battery piece and the light receiving face of the next battery piece in the adjacent battery pieces in the first direction. Therefore, the first battery piece and the second battery piece are close to each other as far as possible, the distance between two adjacent battery pieces can be reduced, more battery pieces can be arranged in an effective space, the number of the battery pieces is increased, and the conversion efficiency of the photovoltaic module is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaic, in particular to a silicon heterojunction solar cell string and a photovoltaic module. BACKGROUND

[0002] With the development of clean energy technology, photovoltaic module technology has emerged. Solar cell pieces, as the power generation main body of photovoltaic modules, realize power generation by converting light energy into electric energy through photoelectric effect or photochemical effect. Improving the photoelectric conversion efficiency of solar cell pieces is of great significance to photovoltaic power generation.

[0003] Heterojunction (HJT) cells have the advantages of high conversion rate, simple manufacturing process, low light decay, and low temperature coefficient. They can reduce the thermal damage of silicon substrates while reducing energy consumption, and have become an important direction for the development of future high-efficiency cells.

[0004] When heterojunction cells are connected in series, the welding strip connects the back surface of the previous heterojunction cell and the next heterojunction cell, and this is repeated to form a cell string. When a cell string is prepared in this way, the two ends of the welding strip are located on the front surface and the back surface, respectively, and the welding strip needs to pass between two heterojunction cells. This will result in a large distance between the two heterojunction cells, reducing the number of heterojunction cells in the limited space, and reducing the conversion efficiency of the photovoltaic module. UTILITY MODEL CONTENT

[0005] Therefore, it is necessary to solve the problem that the distance between two heterojunction cells is large when the heterojunction cells are connected in series, which affects the conversion efficiency. A silicon heterojunction solar cell string and a photovoltaic module are provided, which can reduce the distance between adjacent two cell pieces, set more cell pieces in the effective space, increase the number of cell pieces, and thus increase the light receiving area of the silicon heterojunction solar cell string, and improve the conversion efficiency of the photovoltaic module.

[0006] A silicon heterojunction solar cell string includes a plurality of cell pieces, a plurality of first conductive members, and a plurality of second conductive members.

[0007] The plurality of cell pieces are a plurality of first cell pieces and a plurality of second cell pieces. In the first cell pieces, the N-type doped layer faces the light receiving surface. In the second cell pieces, the P-type doped layer faces the light receiving surface. The plurality of first cell pieces and the plurality of second cell pieces are arranged alternately along a first direction, and adjacent first cell pieces and second cell pieces are close to each other.

[0008] The first conductive piece connects the back light surface of a previous one of the adjacent battery pieces and the back light surface of a next one of the adjacent battery pieces along the first direction, and the second conductive piece connects the light receiving surface of the next one of the adjacent battery pieces and the light receiving surface of a further one of the adjacent battery pieces along the first direction.

[0009] In an embodiment of the present application, the number of the first battery pieces is equal to the number of the second battery pieces.

[0010] The first battery piece is located at the head end of the silicon heterojunction solar cell string, or the second battery piece is located at the head end of the silicon heterojunction solar cell string.

[0011] In an embodiment of the present application, the silicon heterojunction solar cell string further comprises a first output piece and a second output piece, the first output piece connects the light receiving surface of the battery piece at the head end, and the second output piece connects the light receiving surface of the battery piece at the tail end.

[0012] In an embodiment of the present application, the number of the first conductive pieces is greater than or equal to the number of the second conductive pieces.

[0013] In an embodiment of the present application, the battery piece further comprises a plurality of first grid lines and a plurality of second grid lines, the plurality of first grid lines are arranged on the back light surface of the battery piece along a second direction perpendicular to the first direction, and the plurality of second grid lines are arranged on the light receiving surface of the battery piece along the second direction.

[0014] In an embodiment of the present application, the first battery piece and the second battery piece have the same layout of the first grid lines and the second grid lines.

[0015] Alternatively, the first battery piece and the second battery piece have a difference of no more than 10% in the light shielding area of the first grid lines and the second grid lines.

[0016] In an embodiment of the present application, the silicon heterojunction solar cell string further comprises at least one of the following features:

[0017] The first item is that the first battery piece abuts against the adjacent second battery piece.

[0018] The second item is that the number of the first conductive pieces and the second conductive pieces connecting the adjacent battery pieces is a plurality, and the plurality of first conductive pieces and the plurality of second conductive pieces are arranged in the second direction.

[0019] The third item is that when the silicon heterojunction solar cell string is welded, the first conductive piece is placed in the horizontal direction and connects the back light surfaces of the adjacent battery pieces, and the second conductive piece is placed in the horizontal direction and connects the light receiving surfaces of the adjacent battery pieces.

[0020] In an embodiment of the present application, the battery piece comprises a substrate, two intrinsic layers and two transparent conductive layers, wherein one of the transparent conductive layers, the N-type doped layer and one of the intrinsic layers are sequentially stacked on one side surface of the substrate, and the other of the transparent conductive layers, the P-type doped layer and the other of the intrinsic layers are sequentially stacked on the other surface of the substrate.

[0021] In an embodiment of the present application, the conductive layer at the edge of the N-type doped layer and the P-type doped layer is removed by edge etching to form the transparent conductive layer.

[0022] In an embodiment of the present application, the distance between the edge of the transparent conductive layer and the edge of the substrate is 0.1mm-0.5mm.

[0023] The present application also provides a photovoltaic module comprising a cover plate, a back plate and the silicon heterojunction solar cell string according to any one of the technical features described above.

[0024] The cover plate, the back plate and the silicon heterojunction solar cell string are encapsulated by an encapsulation process.

[0025] After adopting the technical solutions described above, the present application has at least the following technical effects:

[0026] The silicon heterojunction solar cell string and the photovoltaic module of the present application, in the silicon heterojunction solar cell string, the first battery pieces and the second battery pieces in the plurality of battery pieces are staggered along the first direction, and adjacent first battery pieces and battery pieces are close to each other. And the first conductive piece connects the previous battery piece and the next battery piece in the adjacent battery pieces on the back light surface, the second conductive piece connects the next battery piece and the further battery piece in the adjacent battery pieces on the light receiving surface, and the first conductive piece and the second conductive piece are connected in this way to form a silicon heterojunction solar cell string.

[0027] The silicon heterojunction solar cell string, since the N-type doped layer of the first battery piece and the P-type doped layer of the second battery piece face the light receiving surface, after the first battery piece and the second battery piece are staggered, the first conductive piece can directly connect the back light surface of the adjacent battery pieces, and the second conductive piece can directly connect the light receiving surface of the adjacent battery pieces. The first conductive piece and the second conductive piece do not need to pass through the light receiving surface and the back light surface of the adjacent battery pieces from the two battery pieces to connect the adjacent battery pieces. In this way, the first battery piece and the second battery piece are as close as possible, the distance between the two adjacent battery pieces is reduced, more battery pieces are arranged in the effective space, the number of battery pieces is increased, and the conversion efficiency of the photovoltaic module is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the silicon heterojunction solar cell string of an embodiment of the present application.

[0029] Figure 2 FIG. 1 is a schematic diagram of a silicon heterojunction solar cell string according to an embodiment of the present application. Figure 1 FIG. 2 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0030] Figure 3 FIG. 3 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application. Figure 2 FIG. 4 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0031] Figure 4 FIG. 5 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application. Figure 2 FIG. 6 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0032] Figure 5 FIG. 7 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application. Figure 1 FIG. 8 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0033] Figure 6 FIG. 9 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application. Figure 1 FIG. 10 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0034] Figure 7 FIG. 11 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application. Figure 1 FIG. 12 is a schematic diagram of a silicon heterojunction solar cell string according to another embodiment of the present application.

[0035] 100, a silicon heterojunction solar cell string; 110, a cell; 111, a first cell; 112, a second cell; 113, a light-receiving surface; 114, a back surface; 115, an N-type doped layer; 116, a P-type doped layer; 117, a substrate; 118, an intrinsic layer; 119, a transparent conductive layer; 120, a first conductive member; 130, a second conductive member; 140, a first output member; 150, a second output member. DETAILED DESCRIPTION

[0036] In order to make the above objectives, features and advantages of the present application more clear and easily understood, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways beyond the specific embodiments described herein without departing from the scope of the present application, and it is understood that similar improvements can be made by those skilled in the art in light of the foregoing description. Therefore, the present application is not limited to the following disclosed specific embodiments.

[0037] In the description of the application, it should be understood that, if there are these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0038] In addition, if there are these terms "first", "second", these terms are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, if the term "multiple" appears, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise explicitly specified.

[0039] In this application, unless otherwise explicitly specified and limited, if there are terms "installation", "connection", "connection", "fixation" and the like, these terms should be broadly understood. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0040] In this application, unless otherwise explicitly specified and limited, if there are similar descriptions such as "first feature on or under the second feature", the meaning can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" of the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" of the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0041] It is to be noted that when an element such as a layer, film, panel, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can also be present. In addition, it is to be understood that the term "comprising" or "having" includes the possibility that there are no additional elements other than the elements recited.

[0042] Currently, when the heterojunction cells are connected in series, the solder strip connects the back surface of the previous heterojunction cell and the next heterojunction cell, and such a process is repeated to form a cell string. When the cell string is prepared by using this method, the two ends of the solder strip are located on the front surface and the back surface, respectively, and the solder strip needs to pass between two heterojunction cells. This will result in a large distance between the two heterojunction cells, reduce the number of heterojunction cells in the limited space, and reduce the conversion efficiency of the photovoltaic module.

[0043] For this purpose, referring to Figure 1 and Figure 2 , the present application provides a novel silicon heterojunction solar cell string 100. Figure 1 A schematic view of a silicon heterojunction solar cell 110 according to an embodiment of the present application is shown in Figure 2 A schematic view of an embodiment of the silicon heterojunction solar cell string 100 is shown in Figure 1 The silicon heterojunction solar cell string 100 can be packaged by using a packaging process to form a photovoltaic module (not shown).

[0044] The silicon heterojunction solar cell string 100 of the present application can reduce the distance between two adjacent cells 110, so as to arrange more cells 110 in the effective space, increase the number of cells 110, and thus increase the light receiving area of the silicon heterojunction solar cell string 100 and improve the conversion efficiency of the photovoltaic module. The specific structure of an embodiment of the silicon heterojunction solar cell string 100 will be described below.

[0045] Referring to Figures 1 to 4 In an embodiment, the silicon heterojunction solar cell string 100 includes a plurality of cells 110, a plurality of first conductive members 120, and a plurality of second conductive members 130. The plurality of cells 110 includes a plurality of first cells 111 and a plurality of second cells 112, the N-type doped layer 115 in the first cell 111 faces the light receiving surface 113 thereof, the P-type doped layer 116 in the second cell 112 faces the light receiving surface 113 thereof, the plurality of first cells 111 and the plurality of second cells 112 are arranged in a staggered manner along a first direction, and adjacent first cells 111 and second cells 112 are close to each other.

[0046] The first conductive member 120 connects the backlight surface 114 of the previous cell 110 and the backlight surface 114 of the next cell 110 in adjacent cells 110 along the first direction, and the second conductive member 130 connects the light-receiving surface 113 of the next cell 110 and the light-receiving surface 113 of the next cell 110 in adjacent cells 110 along the first direction. Figure 3 for Figure 2 The schematic diagram of the silicon heterojunction solar cell string 100 on the light receiving surface 113 is shown. Figure 4 for Figure 2 The silicon heterojunction solar cell string 100 is shown as a schematic diagram on the backlight surface 114 .

[0047] The main structure of the silicon heterojunction solar cell string 100 is a plurality of cells 110, which are silicon heterojunction cells. The cells 110 are used to absorb solar energy and convert it into electrical energy. The plurality of cells 110 are arranged in sequence along a first direction, and each cell 110 extends along the first direction and the second direction, and the first direction is perpendicular to the second direction. Figures 2 to 4 shown, and in Figure 3 and Figure 4 , the first direction is the length direction of the silicon heterojunction solar cell string 100 , and the second direction is the width direction of the silicon heterojunction solar cell string 100 .

[0048] Moreover, each cell 110 has a light-receiving surface 113 and a backlight surface 114. Figure 1 and Figure 2 As shown, the top of the cell 110 is the light-receiving surface 113 (front), and the bottom of the cell 110 is the backlight surface 114 (back). This light-receiving surface 113 and backlight surface 114 also apply to the silicon heterojunction solar cell string 100. The light-receiving surface 113 of the cell 110 faces the sunlight, while the backside of the cell 110 faces away from the sunlight. Sunlight enters the cell 110 from the light-receiving surface 113, enabling the cell 110 to convert solar energy into electrical energy.

[0049] like Figure 5 and Figure 6 As shown, an N-type doping layer 115 and a P-type doping layer 116 are disposed in the cell 110 . Figure 5 for Figure 1 The schematic diagram of the first cell 111 in the silicon heterojunction solar cell string 100 is shown. Figure 6 for Figure 1A schematic view of the second cell 112 in the silicon heterojunction solar cell string 100. The direction in which the N-type doped layer 115 is located is the direction of the negative electrode of the cell 110, and the direction in which the P-type doped layer 116 is located is the direction of the positive electrode of the cell 110. The N-type doped layer 115 and the P-type doped layer 116 form a PN junction to convert solar energy into carriers, and then gather to form an electric current and output.

[0050] The plurality of cells 110 includes a plurality of first cells 111 and a plurality of second cells 112. The first cell 111 is a cell 110 in which the N-type doped layer 115 faces the light-receiving surface 113, and the second cell 112 is a cell 110 in which the P-type doped layer 116 faces the back surface 114. That is, the light-receiving surface 113 of the first cell 111 is the negative electrode, the back surface 114 of the first cell 111 is the positive electrode, the light-receiving surface 113 of the second cell 112 is the positive electrode, and the back surface 114 of the second cell 112 is the negative electrode. The specific structure of the first cell 111 and the second cell 112 will be described later.

[0051] In the plurality of cells 110, the plurality of first cells 111 and the plurality of second cells 112 are arranged alternately in the first direction, as shown in FIG. 1. Figures 1 to 4 As shown, the left end is the head / front end of the silicon heterojunction solar cell string 100, and the right end is the tail / rear end of the silicon heterojunction solar cell string 100. The front-rear direction of the present application is taken as the reference. Figure 1 and Figure 2 The left-right direction shown is the reference.

[0052] The first cell 111 and the second cell 112 are arranged alternately, one second cell 112 is arranged between two adjacent first cells 111, and one first cell 111 is arranged between two adjacent second cells 112. On the light-receiving surface 113, the positive electrode and the negative electrode are arranged alternately in the first direction, and on the back surface 114, the positive electrode and the negative electrode are also arranged alternately in the first direction. The first conductive member 120 and the second conductive member 130 are components that connect a plurality of first cells 111 and a plurality of second cells 112 in series. The first conductive member 120 and the second conductive member 130 are conductive bus bars that can collect the electric current generated by adjacent two cells 110.

[0053] The first conductive member 120 connects adjacent two cells 110 on the back surface 114, and the second conductive member 130 connects adjacent two cells 110 on the light-receiving surface 113. Furthermore, the first conductive member 120 connects an adjacent previous cell 110 and a subsequent cell 110 on the back surface 114, and the second conductive member 130 connects an adjacent subsequent cell 110 and a further cell 110 on the light-receiving surface 113. The previous cell 110, the subsequent cell 110, and the further cell 110 are arranged in the first direction in order.

[0054] At this time, the first conductive member 120 and the second conductive member 130 connect the previous battery piece 110, the next battery piece 110 and the again next battery piece 110 in series, realizing the series connection of the three battery pieces 110. That is, the first conductive member 120 and the second conductive member 130 are partially staggered, the first conductive member 120 and the second conductive member 130 are connected to the middle battery piece 110, and the first conductive member 120 and the second conductive member 130 extend towards opposite directions, the first conductive member 120 is connected to the back light surface 114 of the battery piece 110 adjacent to the middle battery piece 110, and the second conductive member 130 is connected to the light receiving surface 113 of the battery piece 110 adjacent to the middle battery piece 110.

[0055] In the above manner, the plurality of first conductive members 120 and the plurality of second conductive members 130 are connected to the plurality of battery pieces 110 respectively to connect the plurality of battery pieces 110 in series to form the silicon heterojunction solar cell string 100. Of course, in other embodiments of the present application, the first conductive member 120 can be connected to the previous battery piece 110 and the next battery piece 110 on the light receiving surface 113, and the second conductive member 130 can be connected to the next battery piece 110 and the again next battery piece 110 on the back light surface 114.

[0056] The present application is described in the following Figure 2 The number of battery pieces 110 is four, and the connection mode of the first conductive member 120 and the second conductive member 130 is described. The number of battery pieces 110 is four, which are two first battery pieces 111 and two second battery pieces 112, and the first battery piece 111, the second battery piece 112, the first battery piece 111 and the second battery piece 112 are arranged in the first direction in turn. One first conductive member 120 is connected to the first battery piece 111 and the second battery piece 112 on the back light surface 114, the second conductive member 130 is connected to the second battery piece 112 and the first battery piece 111 on the light receiving surface 113, and the other first conductive member 120 is connected to the first battery piece 111 and the second battery piece 112 on the back light surface 114.

[0057] In this way, the silicon heterojunction solar cell string 100 of four battery pieces 110 is formed. The light receiving surface 113 of the first end battery piece 110 of the silicon heterojunction solar cell string 100 is negative, and the light receiving surface 113 of the last end battery piece 110 is positive. The electric equipment is connected by the positive and negative electrodes, the current output is realized, the electric equipment is powered, and the use performance of the electric equipment is ensured.

[0058] Of course, as shown in Figure 7 , Figure 7 , Figure 1The silicon heterojunction solar cell string 100 shown is another embodiment. In another embodiment of the present application, the number of cell pieces 110 can also be eight or other numbers, and the connection manner is substantially the same as that of the number of cell pieces 110 being four, which will not be described herein again.

[0059] The first conductive member 120 connects the adjacent cell pieces 110 at the back light surface 114, and the second conductive member 130 connects the adjacent cell pieces 110 at the light receiving surface 113, so that the first conductive member 120 and the second conductive member 130 do not need to pass through the adjacent cell pieces 110. In this way, the first cell piece 111 and the second cell piece 112 can be close to each other, and the distance between the first cell piece 111 and the second cell piece 112 can be reduced as much as possible, so that more cell pieces 110 can be arranged, and the conversion efficiency of the silicon heterojunction solar cell string 100 can be improved.

[0060] The silicon heterojunction solar cell string 100 of the above embodiment, since the N-type doped layer 115 of the first cell piece 111 and the P-type doped layer 116 of the second cell piece 112 are towards the light receiving surface 113, after the first cell piece 111 and the second cell piece 112 are arranged alternately, the first conductive member 120 can directly connect the back light surface 114 of the adjacent cell pieces 110, and the second conductive member 130 can directly connect the light receiving surface 113 of the adjacent cell pieces 110, so that the first conductive member 120 and the second conductive member 130 do not need to pass through the light receiving surface 113 and the back light surface 114 of the adjacent cell pieces 110 to connect the adjacent cell pieces 110. In this way, the first cell piece 111 and the second cell piece 112 can be close to each other as much as possible, and the distance between the two adjacent cell pieces 110 can be reduced, so that more cell pieces 110 can be arranged in the effective space, the number of cell pieces 110 can be increased, and the conversion efficiency of the photovoltaic module can be improved.

[0061] It is worth noting that in the current solar cell string, each cell piece is arranged in the same manner, i.e., the N-type doped layer is towards the light receiving surface. Two adjacent cell pieces are connected in series, and the conductive member must pass through the anode of the previous cell piece, the gap between the two cell pieces, and the gap of the subsequent cell piece, so that the conductive member is in a Z shape. In this way, the maintenance cost is relatively high, and the disassembly and assembly are troublesome, and at the same time, the size of the cell piece along the first direction is increased.

[0062] To this end, in the silicon heterojunction solar cell string 100 of the present application, the structure of each cell piece 110 is the same, and since the arrangement of the two adjacent cell pieces 110 is opposite, each cell piece 110 is connected in series at the front and back surfaces, so that the silicon heterojunction solar cell string 100 is a symmetrical structure, and the first conductive member 120 and the second conductive member 130 are arranged in a linear shape. In this way, the space utilization rate can be improved, the distance between the two adjacent cell pieces 110 can be reduced, the conversion efficiency per unit length can be improved, and the back surface of the silicon heterojunction solar cell string 100 can also face the sunlight.

[0063] Referring to Figures 1 to 4 In an embodiment, the first cell piece 111 abuts against the adjacent second cell piece 112. That is, the opposite surfaces of the first cell piece 111 and the second cell piece 112 are attached. In this way, the distance between the first cell piece 111 and the second cell piece 112 can be reduced, and the distance between the first cell piece 111 and the second cell piece 112 can be infinitely close to zero, so that more cell pieces 110 can be arranged in the effective space, the number of cell pieces 110 can be increased, and the conversion efficiency of the photovoltaic module can be improved.

[0064] Referring to Figures 1 to 4 In an embodiment, the number of first cell pieces 111 is equal to the number of second cell pieces 112. That is, the first cell pieces 111 and the second cell pieces 112 are arranged one by one, so that the light-receiving surface 113 at the head and the tail of the silicon heterojunction solar cell string 100 forms a positive electrode and a negative electrode, which facilitates the extraction of the current of the silicon heterojunction solar cell string 100.

[0065] Referring to Figures 1 to 4 In an embodiment of the present application, the first cell piece 111 is located at the head of the silicon heterojunction solar cell string 100. That is, the first cell piece 111 is located at the front end of the silicon heterojunction solar cell string 100, and the first cell piece 111, the second cell piece 112, the first cell piece 111, the second cell piece 112, and so on are arranged alternately along the first direction. At this time, the head of the light-receiving surface 113 of the silicon heterojunction solar cell string 100 is a negative electrode, and the tail is a positive electrode.

[0066] Of course, in other embodiments of the present application, the second cell piece 112 is located at the head of the silicon heterojunction solar cell string 100. That is, the second cell piece 112 is located at the front end of the silicon heterojunction solar cell string 100, and the second cell piece 112, the first cell piece 111, the second cell piece 112, the first cell piece 111, and so on are arranged alternately along the first direction. At this time, the head of the light-receiving surface 113 of the silicon heterojunction solar cell string 100 is a positive electrode, and the tail is a negative electrode.

[0067] Referring to Figures 1 to 6In an embodiment, the first conductive member 120 and the second conductive member 130 are solder strips. Further, the first conductive member 120 and the second conductive member 130 are conductive wires. In this way, the first conductive member 120 and the second conductive member 130 have a small diameter, which reduces the shading of sunlight and improves the efficiency of the silicon heterojunction solar cell string 100. Of course, in other embodiments of the present application, the first conductive member 120 and the second conductive member 130 can also be conductive metal strips, etc.

[0068] Referring to Figure 3 and Figure 4 In an embodiment, the number of the first conductive member 120 and the second conductive member 130 connecting the adjacent cell pieces 110 is multiple, and the multiple first conductive members 120 and the multiple second conductive members 130 are arranged in the second direction. That is, the back surface 114 uses multiple first conductive members 120 in the second direction, and the light receiving surface 113 uses multiple second conductive members 130 in the second direction.

[0069] In this way, the multiple first conductive members 120 connect the adjacent two cell pieces 110 on the back surface 114, and the multiple second conductive members 130 connect the adjacent two cell pieces 110 on the light receiving surface 113. Even if the first conductive member 120 and the second conductive member 130 have a small diameter, it will not affect the collection of current.

[0070] Referring to Figures 1 to 3 In an embodiment, the silicon heterojunction solar cell string 100 further includes a first output member 140 and a second output member 150, the first output member 140 connects the light receiving surface 113 of the first cell piece 110, and the second output member 150 connects the light receiving surface 113 of the last cell piece 110. The first output member 140 and the second output member 150 are the positive and negative lead wires of the silicon heterojunction solar cell string 100.

[0071] In Figure 2 and Figure 3 , the first output member 140 connects the light receiving surface 113 of the first cell piece 111, the second output member 150 connects the light receiving surface 113 of the second cell piece 112, the first output member 140 is the negative lead wire, and the second output member 150 is the positive lead wire, and the current output of the silicon heterojunction solar cell string 100 is realized through the first output member 140 and the second output member 150. The layout of the first output member 140 is the same as that of the first conductive member 120, and the layout of the second output member 150 is the same as that of the second conductive member 130.

[0072] Of course, in other embodiments of the present application, the first output member 140 can also be connected to the light-receiving surface 113 of the second cell 112, and the second output member 150 can also be connected to the light-receiving surface 113 of the first cell 111, the first output member 140 being a positive electrode lead, and the second output member 150 being a negative electrode lead.

[0073] Optionally, the first output member 140 and the second output member 150 are conductive wires. Of course, the first output member 140 and the second output member 150 can also be the first conductive member 120 and the second conductive member 130, and have the same layout, except that the first output member 140 and the second output member 150 are connected to only one cell 110.

[0074] Referring to Figure 3 and Figure 4 In an embodiment, the number of the first conductive members 120 is greater than or equal to the number of the second conductive members 130. That is, the number of the first conductive members 120 on the back surface 114 of the silicon heterojunction solar cell 110 and the number of the second conductive members 130 on the light-receiving surface 113 can be different or the same.

[0075] Referring to Figure 3 and Figure 4 In the present embodiment, the number of the first conductive members 120 is greater than the number of the second conductive members 130. In this way, the current collection efficiency of the back surface 114 can be improved, and thus the conversion efficiency of the silicon heterojunction solar cell string 100 can be improved. Of course, in other embodiments of the present application, the number of the first conductive members 120 can also be equal to the number of the second conductive members 130.

[0076] In an embodiment, the cell 110 further comprises a plurality of first grid lines (not shown) and a plurality of second grid lines (not shown), the plurality of first grid lines being arranged on the back surface 114 of the cell 110 along a second direction perpendicular to the first direction, and the plurality of second grid lines being arranged on the light-receiving surface 113 of the cell 110 along the second direction.

[0077] The first grid lines and the second grid lines are auxiliary grid lines of the cell 110, the first grid lines and the second grid lines extend along the second direction and are arranged on the back surface 114 and the light-receiving surface 113 of the cell 110, and the plurality of first grid lines and the plurality of second grid lines are further arranged along the first direction. The first conductive member 120 is arranged on the plurality of first grid lines and connected to the first grid lines, and the second conductive member 130 is arranged on the plurality of second grid lines and connected to the plurality of second grid lines.

[0078] In this way, the plurality of first grid lines can collect the current of the back light surface 114 of the cell piece 110, the plurality of second grid lines can collect the current of the light receiving surface 113 of the cell piece 110, the first conductive member 120 can collect the current of each first grid line, and the second conductive member 130 can collect the current of each second grid line. Alternatively, the first grid line and the second grid line are conductive wires or conductive metal strips, etc.

[0079] In an embodiment, the layout of the first grid line and the second grid line in the first cell piece 111 and the second cell piece 112 is the same. That is, the number and the arrangement position of the first grid line on the back light surface 114 and the second grid line on the light receiving surface 113 of each cell piece 110 are completely the same. In this way, the shielding of the cell piece 110 by the first grid line and the second grid line can be reduced, and the conversion efficiency of the cell piece 110 can be improved.

[0080] Of course, in other embodiments of the present application, the light shielding area of the first grid line and the second grid line in the first cell piece 111 and the second cell piece 112 differs by no more than 10%. That is, the number of the first grid line on the back light surface 114 and the second grid line on the light receiving surface 113 of each cell piece 110 can be different, as long as the light shielding area of the first grid line and the second grid line differs by no more than 10%, so as to ensure the conversion efficiency of the cell piece 110.

[0081] Referring to Figure 1 and Figure 2 In an embodiment, when the silicon heterojunction solar cell string 100 is welded, the first conductive member 120 is arranged in the horizontal direction and connects the back light surfaces 114 of adjacent cell pieces 110, and the second conductive member 130 is arranged in the horizontal direction and connects the light receiving surfaces 113 of adjacent cell pieces 110.

[0082] In this way, the consistency of the connection of each cell piece 110 to the corresponding first conductive member 120 and the second conductive member 130 can be ensured, so that the pressure on the cell piece 110 is more uniform. In this way, a thinner encapsulation film can be used to encapsulate the silicon heterojunction solar cell string 100, thereby reducing the manufacturing cost of the photovoltaic module.

[0083] Referring to Figure 5 and Figure 6 In an embodiment, the cell piece 110 includes a substrate 117, two intrinsic layers 118, and two transparent conductive layers 119, wherein one transparent conductive layer 119, an N-type doped layer 115, and one intrinsic layer 118 are sequentially stacked on one side surface of the substrate 117, and the other transparent conductive layer 119, a P-type doped layer 116, and the other intrinsic layer 118 are sequentially stacked on the other surface of the substrate 117.

[0084] The substrate 117 has two opposite surfaces, and two intrinsic layers 118 are arranged on the two surfaces respectively, one of the intrinsic layers 118 is provided with an N-type doped layer 115 away from the surface of the substrate 117, and the other intrinsic layer 118 is provided with a P-type doped layer 116 away from the surface of the substrate 117. A transparent conductive layer 119 is arranged on the surfaces of the N-type doped layer 115 and the P-type doped layer 116 away from the substrate 117 respectively. The transparent conductive layer 119 is provided with a first gate line, a second gate line, a first conductive part 120 and a second conductive part 130.

[0085] The substrate 117 is an N-type silicon wafer substrate, and the intrinsic layer 118 is an intrinsic amorphous silicon layer or an intrinsic microcrystalline silicon layer. The N-type doped layer 115 is an N-type amorphous silicon layer, and the P-type doped layer 116 is a P-type amorphous silicon layer. The transparent conductive layer 119 is a transparent conductive thin film.

[0086] Figure 5 The first cell 111 is shown in the figure, the N-type doped layer 115 faces upward and is a light-receiving surface 113, and the P-type doped layer 116 faces downward and is a back surface 114. The transparent conductive layer 119, the N-type doped layer 115, the intrinsic layer 118, the substrate 117, the intrinsic layer 118, the P-type doped layer 116 and the transparent conductive layer 119 are sequentially arranged along the direction of the light-receiving surface 113 and the back surface 114.

[0087] Figure 6 The second cell 112 is shown in the figure, the P-type doped layer 116 faces upward and is a light-receiving surface 113, and the N-type doped layer 115 faces downward and is a back surface 114. The transparent conductive layer 119, the P-type doped layer 116, the intrinsic layer 118, the substrate 117, the intrinsic layer 118, the N-type doped layer 115 and the transparent conductive layer 119 are sequentially arranged along the direction of the light-receiving surface 113 and the back surface 114.

[0088] In the preparation of the cell 110, the substrate 117 is first subjected to texturing and cleaning. According to the anisotropic etching principle of alkali on the substrate 117, a pyramid texturing structure is formed on the upper and lower surfaces of the substrate 117 to achieve the purpose of light trapping. At the same time, the surface of the substrate 117 is cleaned by using an industrial standard wet cleaning process (RCA cleaning process) to prepare for the next film plating.

[0089] After cleaning, the intrinsic layer 118, the N-type doped layer 115 and the P-type doped layer 116 are deposited on the two surfaces of the substrate 117. The intrinsic layer 118, the N-type doped layer 115 and the P-type doped layer 116 are deposited on the two surfaces of the substrate 117 by chemical vapor deposition (CVD), specifically amorphous silicon thin film and doped nanocrystalline / microcrystalline silicon thin film, to form a PN junction. The thickness of the N-type doped layer 115 is 15nm-25nm, the thickness of the intrinsic layer 118 is 5nm-8nm, and the thickness of the P-type doped layer 116 is 15nm-25nm.

[0090] Then, a transparent conductive layer 119 is deposited on the N-type doped layer 115 and the P-type doped layer 116. The transparent conductive layer 119 is deposited on the N-type doped layer 115 and the P-type doped layer 116 by physical vapor deposition (PVD) to reduce reflection and conduct electricity. The thickness of the transparent conductive layer 119 is 80 nm to 120 nm.

[0091] Then, the first gate line and the second gate line are deposited on the transparent conductive layer 119 to form the cell piece 110. The metal paste is printed on the transparent conductive layer 119 by screen printing to form the first gate line and the second gate line.

[0092] Subsequently, the cell piece 110 is tested and sorted to test the electrical performance parameters of the cell piece 110. The cell piece 110 is tested under standard IV test conditions, the electrical performance parameters of the cell piece 110 are tested, and the cell piece 110 is graded according to the short-circuit current (Isc).

[0093] When the cell piece 110 passes the test, the welding equipment is used to weld and connect the plurality of cell pieces 110, the first conductive member 120, and the second conductive member 130 to form the silicon heterojunction solar cell string 100.

[0094] In an embodiment, the edge etching method is used to remove the conductive layer at the edge of the N-type doped layer 115 and the P-type doped layer 116 to form the transparent conductive layer 119. After the transparent conductive layer 119 is deposited on the N-type doped layer 115 and the P-type doped layer 116, the edge of the transparent conductive layer 119 needs to be edge etched, and the conductive layer around the cell piece 110 and the chamfer is removed by chemical or physical method to form the required transparent conductive layer 119 on the N-type doped layer 115 and the P-type doped layer 116.

[0095] In an embodiment, the distance between the edge of the transparent conductive layer 119 and the edge of the substrate 117 is 0.1 mm to 0.5 mm. In this way, the conductive performance of the transparent conductive layer 119 can be ensured.

[0096] The silicon heterojunction solar cell string 100 of the present application, since the N-type doped layer 115 of the first cell piece 111 and the P-type doped layer 116 of the second cell piece 112 are towards the light-receiving surface 113, after the first cell piece 111 and the second cell piece 112 are arranged staggeredly, the first conductive member 120 can be directly connected to the back surface 114 of the adjacent cell piece 110, and the second conductive member 130 can be directly connected to the light-receiving surface 113 of the adjacent cell piece 110, and the first conductive member 120 and the second conductive member 130 do not need to pass through the light-receiving surface 113 and the back surface 114 of the adjacent cell piece 110 from between the two cell pieces 110, so that the first cell piece 111 and the second cell piece 112 are as close as possible, the distance between the two adjacent cell pieces 110 is reduced, more cell pieces 110 are arranged in the effective space, the number of cell pieces 110 is increased, and the conversion efficiency of the photovoltaic module is improved.

[0097] The present application also provides a photovoltaic module, comprising a cover plate, a back plate and the silicon heterojunction solar cell string 100 in any of the above embodiments. The cover plate, the back plate and the silicon heterojunction solar cell string 100 are encapsulated by an encapsulation process. The photovoltaic module of the present application uses the silicon heterojunction solar cell string 100 of the above embodiments, so that more cell pieces 110 can be arranged in a limited space, and the conversion efficiency of the photovoltaic module is improved.

[0098] The technical features of the above embodiments can be combined in any way. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0099] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A string of silicon heterojunction solar cells, characterized in that, The plurality of battery pieces, the plurality of first conductive pieces, and the plurality of second conductive pieces; The plurality of battery pieces includes a plurality of first battery pieces and a plurality of second battery pieces, the N-type doped layer of the first battery piece faces the light-receiving surface thereof, the P-type doped layer of the second battery piece faces the light-receiving surface thereof, the plurality of first battery pieces and the plurality of second battery pieces are staggered along a first direction, and adjacent first battery pieces and second battery pieces are close to each other; The first conductive piece connects the back surface of a previous battery piece and the back surface of a next battery piece of adjacent battery pieces along the first direction, and the second conductive piece connects the light-receiving surface of the next battery piece and the light-receiving surface of a further battery piece of adjacent battery pieces along the first direction.

2. The silicon heterojunction solar cell string of claim 1, wherein, The number of first battery pieces is equal to the number of second battery pieces. The first battery piece is located at the head end of the silicon heterojunction solar cell string, or the second battery piece is located at the head end of the silicon heterojunction solar cell string.

3. The silicon heterojunction solar cell string of claim 1, wherein, The silicon heterojunction solar cell string further comprises a first output piece and a second output piece, the first output piece is connected to the light-receiving surface of the battery piece at the head end, and the second output piece is connected to the light-receiving surface of the battery piece at the tail end.

4. The silicon heterojunction solar cell string of claim 1, wherein, The number of first conductive pieces is greater than or equal to the number of second conductive pieces.

5. The silicon heterojunction solar cell string of claim 1, wherein, The battery piece further comprises a plurality of first grid lines and a plurality of second grid lines, the plurality of first grid lines is arranged on the back surface of the battery piece along a second direction perpendicular to the first direction, and the plurality of second grid lines is arranged on the light-receiving surface of the battery piece along the second direction.

6. The silicon heterojunction solar cell string of claim 5, wherein, The first grid lines and the second grid lines in the first battery piece and the second battery piece have the same layout form. Alternatively, the light-shielding area of the first grid lines and the second grid lines in the first battery piece and the second battery piece differs by no more than 10%.

7. The silicon heterojunction solar cell string of claim 1, wherein, The silicon heterojunction solar cell string further comprises at least one of the following features: The first battery piece and the adjacent second battery piece are in abutment. The number of first conductive pieces and second conductive pieces connecting adjacent battery pieces is a plurality, and the plurality of first conductive pieces and the plurality of second conductive pieces are spaced apart along a second direction. When the silicon heterojunction solar cell string is welded, the first conductive piece is placed along the horizontal direction and connects the back surface of adjacent battery pieces, and the second conductive piece is placed along the horizontal direction and connects the light-receiving surface of adjacent battery pieces.

8. The silicon heterojunction solar cell string according to any one of claims 1 to 7, characterized in that, The battery piece comprises a substrate, two intrinsic layers, and two transparent conductive layers, one of the transparent conductive layers, the N-type doped layer, and one of the intrinsic layers are sequentially stacked on one side surface of the substrate, and the other of the transparent conductive layers, the P-type doped layer, and the other of the intrinsic layers are sequentially stacked on the other surface of the substrate.

9. The silicon heterojunction solar cell string of claim 8, wherein, The edge of the transparent conductive layer and the edge of the substrate are 0.1mm-0.5mm apart.

10. The silicon heterojunction solar cell string of claim 9, wherein, ​ 11. A photovoltaic module, characterized by The silicon heterojunction solar cell string as claimed in any one of claims 1 to 10, wherein the backsheet is a backsheet of a backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / backsheet / back ​

Images