Half-cut photovoltaic cell string and photovoltaic module

Abstract

The present application relates to the field of photovoltaic technology, and discloses a half-cut photovoltaic cell string and a photovoltaic module. The half-cut photovoltaic cell string comprises multiple cells and multiple ribbons. By arranging the multiple cells in a first direction, the cut surface of one of two adjacent cells corresponds to the isolation surface of the other of the two adjacent cells, and the orientations of the positive and negative electrodes of the cells are kept consistent, facilitating subsequent welding operations; a same ribbon connects two adjacent cells, achieving series connection of the multiple cells; in addition, by configuring the distance L1 between each ribbon and a first intersection line and the distance L2 between the ribbon and a second intersection line to satisfy the condition L1>2×L2, the distance from the ribbon to a PN junction on the cut surface is much greater than the distance from the ribbon to a corresponding position of a PN junction on the isolation surface, thereby avoiding the risk that the ribbon is too close to or in contact with the exposed PN junction on the cut surface, mitigating electric leakage or short circuits, and improving the reliability of the half-cut photovoltaic cell string.

Description

Half-cell photovoltaic cell string and photovoltaic module

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202422064041.9, filed on August 23, 2024, and entitled "Half-cell photovoltaic cell string and photovoltaic module", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the field of photovoltaic technology, in particular to a half-cell photovoltaic cell string and a photovoltaic module. BACKGROUND

[0004] The photovoltaic cell string is the main component in the photovoltaic module, and its main function is to convert solar energy into electrical energy. The photovoltaic cell string is to connect several cell pieces in series to improve the output voltage. At present, the cell pieces applied on the module are mainly half-cell pieces, and the use of half-cell pieces in the photovoltaic module has higher conversion efficiency and lower cost. The half-cell piece is a square or rectangular cell piece cut along the direction perpendicular to the cell piece electrode (main grid). After the cell is cut, each cell piece needs to be welded to realize the series connection of several cell pieces, thereby forming a half-cell photovoltaic cell string. Specifically, each two cell pieces are connected by a welding strip, and the welding strip is welded with the electrode on the cell piece.

[0005] Usually, the cell piece has an isolation layer around the periphery, and the cell piece is protected by the isolation layer. However, after the cell is divided into two half-cell pieces, there will be no isolation layer at the cutting surface position, and the PN junction in the internal structure of the cell will be exposed outside. Since the welding strip is connected between the two half-cell pieces, there is a risk that the welding strip is too close to or in contact with the PN junction at the cutting surface of the half-cell piece, which may cause electric leakage or short circuit, and has a huge safety hazard. SUMMARY

[0006] Therefore, the present application provides a half-cell photovoltaic cell string and a photovoltaic module to solve the problem that the welding strip is too close to or in contact with the PN junction at the cutting surface of the half-cell piece.

[0007] In a first aspect, the application provides a half-piece photovoltaic cell string, comprising: a plurality of cell pieces arranged along a first direction, each of the cell pieces having a cut surface on a first side along the first direction and a separation surface with a separation layer on a second side, each of the cell pieces being provided with a positive electrode on a front surface and a negative electrode on a back surface, each of the cell pieces having a PN junction, the PN junction intersecting with the cut surface to form a first intersection line, and the PN junction intersecting with the separation surface to form a second intersection line; and a plurality of solder strips, each of the solder strips being welded at one end to the positive electrode on one of the cell pieces and at the other end to the negative electrode on another of the cell pieces, at least a partial section of each of the solder strips being located between the two adjacent cell pieces on a shortest line between the first intersection line on one of the cell pieces and the second intersection line on the other of the cell pieces, a distance between the solder strip and the first intersection line being L1, and a distance between the solder strip and the second intersection line being L2, wherein L1≥2×L2.

[0008] Beneficial effects: By arranging the plurality of cell pieces along the first direction, the cut surfaces of the cell pieces are all oriented in the same direction, and the separation surfaces of the cell pieces are all oriented in the same direction opposite to the orientation of the cut surfaces, so that the cut surface of one of the two adjacent cell pieces corresponds to the separation surface of the other of the two adjacent cell pieces, and the orientations of the positive and negative electrodes of the cell pieces remain consistent, facilitating subsequent soldering operation. By welding one end of the solder strip to the positive electrode on one of the cell pieces and the other end to the negative electrode on another of the cell pieces, the same solder strip connects the two adjacent cell pieces, thereby realizing the series connection of the plurality of cell pieces. Furthermore, by arranging the solder strip on the shortest line between the first intersection line formed by the PN junction intersecting with the cut surface on one of the cell pieces and the second intersection line formed by the PN junction intersecting with the separation surface on the other of the cell pieces, and by satisfying the relationship between the distance L1 between the solder strip and the first intersection line and the distance L2 between the solder strip and the second intersection line, i.e. L1≥2×L2, for the corresponding cut surface and separation surface, the distance from the solder strip to the PN junction on the cut surface is much greater than the distance from the solder strip to the corresponding position of the PN junction on the separation surface, thereby avoiding the risk of the solder strip being too close to or contacting the exposed PN junction on the cut surface due to the offset of the solder strip, and further avoiding the risk of electric leakage due to the tin residue on the surface of the solder strip 2 falling or splashing onto the exposed cut surface during the soldering process, thereby improving the electric leakage or short circuit condition and improving the reliability and quality of the half-piece photovoltaic cell string.

[0009] In an alternative embodiment, the distance between the PN junction and the front side of the cell is less than the distance between the PN junction and the back side of the cell; the solder strip comprises a first solder segment and a second solder segment, the first solder segment of each solder strip is soldered to the positive electrode of one of the two adjacent cells on the first side, and the second solder segment is soldered to the negative electrode of one of the two adjacent cells on the second side.

[0010] Beneficial effects: by arranging the solder strip to connect between the positive electrode of one cell on the first side and the negative electrode of another cell on the second side, the intersection of the shortest line between the first intersection line and the second intersection line and the solder strip is closer to the cell on the first side, thereby achieving the purpose of avoiding the situation of electric leakage or short circuit during soldering.

[0011] In an alternative embodiment, in the first direction, the first end of the second solder segment is directly or indirectly connected to the second end of the first solder segment, the first end of the first solder segment is close to and spaced apart from the cutting surface of one of the cells connected thereto, and the second end of the second solder segment is close to and spaced apart from the isolation surface of one of the cells connected thereto.

[0012] Beneficial effects: by arranging the first end of the first solder segment to be close to and spaced apart from the cutting surface of the cell, it can not only ensure that the solder strip has sufficient soldering length with the positive electrode, but also avoid the solder strip overlapping on the cutting surface, thereby avoiding short circuit and ensuring the reliability of soldering. Similarly, by arranging the second end of the second solder segment to be close to and spaced apart from the isolation surface of one of the cells on the first side, it can not only ensure that the solder strip has sufficient soldering length with the negative electrode, but also avoid wasting materials and facilitate processing.

[0013] In an alternative embodiment, the plurality of cells are arranged at equal intervals in the first direction, the positive electrodes of each of the cells are located in the same plane, and the negative electrodes of each of the cells are located in the same plane; and the solder strip connected to two of the cells is in a bent shape, the solder strip further comprises a connecting segment connected between the first solder segment and the second solder segment, and the connecting segment is located in the interval between the two adjacent cells.

[0014] Beneficial effects: By arranging a plurality of battery pieces in equal intervals along the first direction, and arranging the positive electrodes of each battery piece in the same plane and the negative electrodes in another same plane, the arrangement and processing of the plurality of battery pieces are facilitated. By arranging the welding strip in a bent shape, the connecting section between the first welding section and the second welding section is arranged in the interval between the adjacent two battery pieces, the plurality of battery pieces are sequentially connected in series, the arrangement relationship that the distance L between the welding strip and the first intersection line is greater than or equal to the multiple of the distance L between the welding strip and the second intersection line is facilitated, and the reliability and safety of the welding process are ensured.

[0015] In an alternative embodiment, the adjacent two battery pieces are arranged without interval, and the plurality of battery pieces are arranged in a stepped shape, and the welding strip is arranged in a straight line shape.

[0016] Beneficial effects: The size of the half-piece photovoltaic cell string in the first direction is reduced, the space is saved, and the cost is reduced.

[0017] In an alternative embodiment, the battery piece is cut from a whole piece of battery, the cutting line is perpendicular to the extension direction of the electrode, the cutting position is the front surface or the back surface of the battery piece, the cutting method is a combination of laser cutting and heat treatment, the damage zone is formed on the cutting surface by laser cutting, the damage zone is located at both ends of the cutting line, and the length of the damage zone along the extension direction of the cutting line is less than 1 cm.

[0018] Beneficial effects: By arranging the cutting method as a combination of laser cutting and heat treatment, the damage zone formed on the cutting surface by laser cutting is located at both ends of the cutting line, and the length of the damage zone along the extension direction of the cutting line is less than 1 cm. The damage zone only occupies part of the area of one side of the battery piece, and the influence of the damage zone on the battery piece can be effectively reduced, so as to ensure the performance of the battery piece.

[0019] In an alternative embodiment, the battery piece is cut from a whole piece of battery by laser cutting, the cutting line is perpendicular to the extension direction of the electrode, a damage zone is formed on the cutting surface, the damage zone covers the entire cutting line, and the cutting position is the back surface of the battery piece.

[0020] Beneficial effects: The battery piece is directly cut from a whole piece of battery by laser cutting, the cutting method is simple and easy to operate, and the production efficiency is high. By arranging the cutting position on the back surface of the battery piece, the damage zone formed on the cutting surface by laser cutting can be as far away from the PN junction as possible, so as to reduce the influence on the PN junction and ensure the quality of the battery piece.

[0021] In an alternative embodiment, the front surface and the back surface of the battery piece are both covered with the isolation layer, and the isolation layer is an insulating material with light transmission.

[0022] Beneficial effects: By covering the isolation layer on the front and back of the battery piece, all surfaces on the battery piece except the cutting surface are covered with the isolation layer. The isolation layer acts as a protective layer, protecting the internal structure of the battery piece, isolating the positive and negative electrodes, reducing surface defects, reducing reflection, etc. It avoids the influence of external substances on the battery function, reduces electron recombination or leakage, thereby improving the performance of the battery piece.

[0023] In an alternative embodiment, the number of positive electrodes and negative electrodes on each battery piece is n, and the number of welding strips connected to each battery piece is n, wherein n is a positive integer greater than or equal to 8.

[0024] Beneficial effects: The connection between the battery pieces is more intensive, which can more effectively collect and transmit current and improve power generation efficiency.

[0025] In a second aspect, the application also provides a photovoltaic module, comprising: a frame; a laminated piece installed in the frame, the laminated piece comprising the above-mentioned half-piece photovoltaic cell string. Because the photovoltaic module comprises the half-piece photovoltaic cell string, it has the same effects as the half-piece photovoltaic cell string, which will not be described here. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0027] Figure 1 is a structural schematic diagram of a half-piece photovoltaic cell string according to an embodiment of the present application;

[0028] Figure 2 is a partial enlarged schematic diagram of A in Figure 1;

[0029] Figure 3 is a structural schematic diagram of another half-piece photovoltaic cell string according to an embodiment of the present application;

[0030] Figure 4 is a structural schematic diagram of a battery piece according to an embodiment of the present application;

[0031] Figure 5 is a top view of the battery piece shown in Figure 4;

[0032] Figure 6 is a partial enlarged schematic diagram of B in Figure 5;

[0033] Figure 7 is a top view of another battery piece according to an embodiment of the present application;

[0034] Figure 8 is a structural schematic diagram of a whole-piece battery according to an embodiment of the present application;

[0035] Fig. 9 is a structural schematic diagram of a photovoltaic module according to an embodiment of the present application.

[0036] Reference signs: 1, cell; 101, isolation layer; 102, P-type region; 103, N-type region; 111, cutting surface; 112, isolation surface; 113, damage region; 121, positive electrode; 122, negative electrode; 130, PN junction; 2, solder strip; 201, first soldering section; 202, second soldering section; 203, connecting section; 3, frame; 301, upper structure; 302, middle structure; 303, lower structure; 4, laminated component. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0038] The embodiments of the present application will be described below with reference to Figs. 1 to 9.

[0039] According to an embodiment of the present application, in one aspect, a half-cell photovoltaic cell string is provided, as shown in Figs. 1 to 7, the half-cell photovoltaic cell string comprising: a plurality of cell pieces 1 and a plurality of solder strips 2, the plurality of cell pieces 1 being arranged along a first direction, each cell piece 1 having a cutting surface 111 on a first side along the first direction and an isolation surface 112 with an isolation layer 101 on a second side, a positive electrode 121 being arranged on a front surface of each cell piece 1 and a negative electrode 122 being arranged on a back surface of each cell piece 1, each cell piece 1 having a PN junction 130, the PN junction 130 intersecting with the cutting surface 111 to form a first intersection line and intersecting with the isolation surface 112 to form a second intersection line; one end of each solder strip 2 being soldered to the positive electrode 121 on one cell piece 1 and the other end being soldered to the negative electrode 122 on another cell piece 1, at least part of each solder strip 2 being located between two adjacent cell pieces 1, the shortest line between the first intersection line on one cell piece 1 and the second intersection line on the adjacent another cell piece 1, a distance between the solder strip 2 and the first intersection line being L1 and a distance between the solder strip 2 and the second intersection line being L2, wherein L1≥2×L2.

[0040] The first direction refers to the "first direction" indicated by the arrow in FIG. 1 and FIG. 3; the first side and the second side are opposite two sides in the first direction; the line between the front and back of the cell piece 1 is perpendicular to the line between the cutting surface 111 and the isolation surface 112; the cell piece 1 is a half-piece photovoltaic cell cut from a whole cell, and the whole cell is surrounded by an isolation layer 101 on all four sides, including the upper surface, the lower surface, and each side surface, to protect the internal structure of the cell; the cell piece 1 formed after cutting has a cutting surface 111, and the cutting surface 111 is free of the isolation layer 101, so that the internal structure of the cell is exposed at the cutting surface; the PN junction exposed outside is prone to danger when in contact with the solder strip 2; the shortest line between the first intersection line on one cell piece 1 and the second intersection line on the adjacent other cell piece 1 refers to a line that is between the adjacent two cell pieces 1 and perpendicular to the first intersection line and the second intersection line.

[0041] The half-piece photovoltaic cell string of the embodiment is arranged by arranging a plurality of cell pieces 1 in the first direction, with the cutting surface 111 of each cell piece 1 facing the same direction, the isolation surface 112 of each cell piece 1 facing the same direction and opposite to the direction of the cutting surface 111, ensuring that the cutting surface 111 of one of the adjacent two cell pieces 1 corresponds to the isolation surface 112 of the other, and the positive and negative electrodes of each cell piece 1 have the same orientation, facilitating subsequent soldering operations. By arranging the solder strip 2 with one end soldered to the positive electrode 121 of one cell piece 1 and the other end soldered to the negative electrode 122 of the other cell piece 1, the same solder strip 2 connects two adjacent cell pieces, thereby realizing the series connection of a plurality of cell pieces 1. Furthermore, by arranging the shortest line between the first intersection line formed by the intersection of the PN junction 130 on one cell piece 1 and the cutting surface 111 and the second intersection line formed by the intersection of the PN junction 130 on the adjacent other cell piece 1 and the isolation surface 112, and the distance L1 between the solder strip 2 and the first intersection line and the distance L2 between the solder strip 2 and the second intersection line satisfy L1≥2×L2, for the corresponding one cutting surface 111 and isolation surface 112, the distance from the solder strip 2 to the PN junction 130 on the cutting surface 111 is much greater than the distance from the solder strip 2 to the corresponding position of the PN junction 130 on the isolation surface 112, thereby avoiding the risk of the solder strip 2 being too close to or in contact with the exposed PN junction 130 on the cutting surface 111 due to the offset of the solder strip 2. Furthermore, the design of being far away from the exposed PN junction 130 can avoid the tin residue on the surface of the solder strip falling or splashing onto the exposed cutting surface 111 during the soldering process, thereby improving the leakage or short circuit situation and improving the reliability and quality of the half-piece photovoltaic cell string.

[0042] It should be noted that the cross-sectional structure of the whole battery is shown in Figure 8. Taking an N-type battery as an example, the base is an N-type region 103, the upper surface is the front surface of the battery, and the P-type region 102 is arranged at the front surface position. The interface between the N-type region 103 and the P-type region 102 forms a PN junction (the boundary or interface between two semiconductor materials). In the case of light excitation, the front surface of the battery forms a positive electrode, and the back surface forms a negative electrode, and the battery piece becomes a power source. It is worth mentioning that the PN junction 130 in the embodiment refers to the electrode structure that has the greatest impact on the power generation capacity after the battery piece is made into a module, that is, the space potential barrier region that has the greatest impact on power generation. In fact, in a photovoltaic cell, similar PN junction structures often exist in multiple places, such as the concentration difference position formed by N and N+ or P and P+, such as the metal-semiconductor contact position, etc. These are not considered in the embodiment. Among them, the front surface refers to the upper surface, the upper surface refers to the surface in the direction of "up" indicated by the arrow in Figure 8; the back surface refers to the lower surface, that is, the surface in the direction of "down" indicated by the arrow in Figure 8; the formation of the P-type region includes but is not limited to high-temperature diffusion and ion implantation.

[0043] The outer surface of the whole battery has an isolation layer 101 as a protective layer. After the whole battery is cut into two half batteries, the internal materials and PN junction 130 of the battery at the cutting position are exposed, which has the risk of short circuit or leakage caused by the overlap of the solder strip 2 and the PN junction 130. If further oxidation or other operations are performed to form an insulating protection at the battery cutting surface, the operation at the module end is too complex, and a large amount of manpower and material resources need to be consumed, which is not cost-effective. If natural oxidation is used, it is also not very realistic, and cannot form effective protection. The half photovoltaic cell string of the embodiment is arranged to be away from the PN junction exposed on the cutting surface 111, thereby reducing the probability of the solder strip 2 being too close or in contact with the cutting surface.

[0044] In one embodiment, the distance between the PN junction 130 and the front surface of the cell piece 1 is less than the distance between the PN junction 130 and the back surface of the cell piece 1; the solder strip 2 comprises a first soldering section 201 and a second soldering section 202, the first soldering section 201 of each solder strip 2 is soldered with the positive electrode 121 on one of the two adjacent cell pieces 1 on the first side, and the second soldering section 202 is soldered with the negative electrode 122 on one of the two adjacent cell pieces 1 on the second side. It should be noted that the positive electrode 121 is arranged on the front surface of the cell piece 1, and the negative electrode 122 is arranged on the back surface of the cell piece 1, in the two adjacent cell pieces 1, the isolation surface 112 on one of the cell pieces 1 on the first side is closer to the solder strip 2 than the cut surface 111, the cut surface 111 on the cell piece 1 on the second side is closer to the solder strip 2 than the isolation surface 112, and the distance between the PN junction 130 and the front surface of the cell piece 1 is set to be less than the distance between the PN junction 130 and the back surface of the cell piece 1, so that the distance between the PN junction 130 and the positive electrode 121 on the same cell piece 1 is less than the distance between the PN junction 130 and the negative electrode 122. By arranging the solder strip 2 to be connected between the positive electrode 121 of one of the cell pieces 1 on the first side and the negative electrode 122 of another cell piece 1 on the second side, the intersection point of the shortest line between the first intersection line and the second intersection line and the solder strip 2 is closer to the cell piece on the first side, so as to achieve that between the two adjacent cell pieces 1, the distance between the solder strip 2 between the two cell pieces 1 and the PN junction 130 on the cell piece 1 on the second side is greater than the distance between the solder strip 2 and the PN junction 130 on the cell piece 1 on the first side on the shortest line between the first intersection line and the second intersection line, and further to achieve the purpose of avoiding the situation of electric leakage or short circuit during soldering.

[0045] In one embodiment, in the first direction, the first end of the second soldering section 202 is directly or indirectly connected with the second end of the first soldering section 201, the first end of the first soldering section 201 is close to and spaced apart from the cutting surface 111 of one battery piece 1 connected therewith, and the second end of the second soldering section 202 is close to and spaced apart from the isolation surface 112 of one battery piece 1 connected therewith. Wherein the first end and the second end are two opposite ends of a soldering section in the first direction, the first end refers to an end on the first side of the first direction, and the second end refers to an end on the second side of the first direction. The first end of the second soldering section 202 is connected with the second end of the first soldering section 201, and the connection is located between the two adjacent battery pieces 1, the first soldering section 201 is welded on the positive electrode 121 of one battery piece 1 on the first side, by setting the first end of the first soldering section 201 close to and spaced apart from the cutting surface 111 of the battery piece 1, it can not only ensure that the solder strip 2 has sufficient welding length with the positive electrode 121, but also avoid the solder strip 2 overlapping on the cutting surface 111, thereby avoiding short circuit and ensuring the reliability of welding. Similarly, by setting the second end of the second soldering section 202 close to and spaced apart from the isolation surface 112 of one battery piece 1 on the first side, it can not only ensure that the solder strip 2 has sufficient welding length with the negative electrode 122, but also avoid wasting materials and facilitate processing.

[0046] In one embodiment, the first side refers to the side of the direction of "right" indicated by the arrow in FIG. 1 and FIG. 3, and the second side refers to the side of the direction of "left" indicated by the arrow in FIG. 1 and FIG. 3. For two adjacent battery pieces 1, the battery piece 1 on the right side is defined as the first battery piece, and the battery piece on the left side is defined as the second battery piece, then the cutting surface 111 of each battery piece 1 faces right, the isolation surface 112 of each battery piece faces left, the first soldering section 201 of each solder strip 2 is welded with the positive electrode 121 of the first battery piece, and the second soldering section 202 is welded with the negative electrode 122 of the second battery piece; the right end of the first soldering section 201 is close to the cutting surface 111 on the first battery piece and spaced apart from the cutting surface 111 in the first direction; and the left end of the second soldering section 202 is close to the isolation surface 112 of the second battery piece and spaced apart from the isolation surface 112 in the first direction.

[0047] In one embodiment, further in combination with FIGS. 1-2, the plurality of battery pieces 1 are arranged equidistantly along the first direction, the positive electrode 121 of each battery piece 1 is located in the same plane, and the negative electrode 122 of each battery piece 1 is located in the same plane; meanwhile, the welding strip 2 connected with two battery pieces 1 is bent, and the welding strip 2 further comprises a connecting section 203 connected between the first welding section 201 and the second welding section 202, and the connecting section 203 is located in the interval between the adjacent two battery pieces 1. It should be noted that the connecting section 203 is connected between the second end of the first welding section 201 and the first end of the second welding section 202, that is, the first end of the second welding section 202 and the second end of the first welding section 201 are indirectly connected; if the plurality of battery pieces 1 are equidistantly distributed along the first direction, the isolation surface 112 of one of the adjacent two battery pieces 1 and the cutting surface 111 of the other are oppositely arranged, the shortest line between the first intersection line and the second intersection line is perpendicular to the cutting surface 111 and the isolation surface 112, and the connecting section 203 on the welding strip 2 is located between the oppositely arranged isolation surface 112 and cutting surface 111; since the distance from the PN junction 130 to the positive electrode 121 is less than the distance from the PN junction 130 to the negative electrode 122, the intersection point of the shortest line between the first intersection line and the second intersection line and the welding strip 2 is closer to the front surface of the battery piece 1, that is, closer to the turning position where the first welding section 201 and the connecting section 203 are connected, the turning position where the first welding section 201 and the connecting section 203 are connected overlaps on the battery piece 1 located on the right side, and corresponds to the edge intersecting with the isolation surface 112 and the front surface on the battery piece 1, and the isolation layer 101 at this position protects against short circuit risk of the welding strip 2 contacting the inside of the battery piece 1, and correspondingly, the welding strip 2 is far away from the battery piece 1 located on the left side, and the probability of contacting the PN junction on the cutting surface 111 is also reduced.

[0048] By arranging the plurality of battery pieces 1 equidistantly along the first direction and the positive electrode 121 of each battery piece 1 in the same plane and the negative electrode 122 in another same plane, the arrangement and processing of the plurality of battery pieces 1 are facilitated, and by arranging the welding strip 2 in a bent shape, the connecting section 203 connected between the first welding section 201 and the second welding section 202 is located in the interval between the adjacent two battery pieces 1, the plurality of battery pieces 1 are sequentially connected in series, and the arrangement relationship that the distance L1 between the welding strip 2 and the first intersection line is greater than or equal to 2 times the distance L2 between the welding strip 2 and the second intersection line is facilitated, thereby ensuring the reliability and safety of the welding process.

[0049] Specifically, further in combination with FIG. 1, in the process of assembling the half-cell string, first, the rightmost solder strip 2 (the lower solder strip) is placed, then the first cell piece 1 on the rightmost is placed, and in the process of placing, the cutting surface 111 of the cell piece 1 is ensured to be placed towards the right; after the cell piece 1 on the rightmost is placed, the PN junction 130 on the cutting surface 111 of the cell piece 1 is away from the lower solder strip, that is, the damage layer at the upper right corner of the cell piece 1 and the PN junction 130 are free of the solder strip 2; then the upper solder strip is placed, the first welding section 201 on the right side of the solder strip 2 is connected with the positive electrode 121 on the front surface of the first cell piece 1, and the second welding section 202 on the left side is to be welded with the negative electrode 122 on the back surface of the second cell piece; then, the second cell piece 1 is placed on the second welding section 202 of the solder strip 2, and so on, a plurality of cell pieces 1 are sequentially placed in the welding equipment from right to left, and finally the welding equipment on the right side welds each cell piece 1 with the welding area on the corresponding solder strip. Through this way, in the half-cell string set in this way, in the two adjacent cell pieces 1, the isolation surface 112 on the cell piece 1 on the right side (that is, the first cell piece) is opposite to the cutting surface 111 on the cell piece 1 on the left side (that is, the second cell piece), and then the distance L1 between the PN junction 130 on the cutting surface 111 of the second cell piece and the solder strip 2 will be much greater than the distance L2 between the PN junction 130 on the isolation surface 112 of the first cell piece and the solder strip 2.

[0050] In addition, in other embodiments, further in combination with FIG. 3, two adjacent battery pieces 1 are arranged with zero spacing, a plurality of battery pieces 1 are arranged in a stepped manner, the welding strip 2 is in a linear shape, the welding strip 2 is free of the connecting section 203, and the first end of the second welding section 202 of the welding strip 2 is directly connected to the second end of the first welding section 201. The size of the half-piece photovoltaic cell string in the first direction is reduced, space is saved, and cost is reduced. It should be noted that the cutting surface 111 of each battery piece 1 is arranged towards the right; in the two adjacent battery pieces 1, the isolation surface 112 of the first battery piece and the cutting surface 111 of the second battery piece are located in the same plane, the zero-spacing arrangement of the battery pieces is achieved, the shortest line connecting the first intersection line and the second intersection line is located in the plane where the isolation surface 112 of the first battery piece and the cutting surface 111 of the second battery piece are located and is perpendicular to the extension direction of the welding strip 2; the PN junction 130 is closer to the front surface of the battery piece 1, the straight-line distance between the PN junction 130 and one of the welding strips 2 connected to the negative electrode of the battery piece 1 is much greater than the straight-line distance between the PN junction 130 and the other welding strip 2 connected to the positive electrode of the battery piece 1, the right end of the one of the welding strips 2 connected to the positive electrode of the same battery piece 1 is arranged to be spaced apart from the cutting surface 111 of the battery piece 1, which can reduce the influence of the welding strip 2 on the cutting surface 111 during the welding process of the positive electrode 121, and at the same time, the other welding strip 2 connected to the negative electrode of the battery piece 1 is located on the back surface of the battery piece 1 and is far away from the PN junction, which can also reduce the influence on the PN junction during the welding process. Similarly, for the two battery pieces 1 connected to the same welding strip 2, the straight-line distance between the PN junction on the cutting surface 111 of the second battery piece located on the left and the welding strip 2 is much greater than the straight-line distance between the PN junction on the isolation surface 112 of the first battery piece located on the right and the welding strip 2, so that the risk of the welding strip 2 being too close to or contacting the PN junction 130 exposed on the cutting surface 111 can be avoided, thereby improving the situation of electric leakage or short circuit.

[0051] In one embodiment, further in combination with FIGS. 5 and 6, the battery piece 1 is cut from a whole piece of battery, the cutting line is perpendicular to the extension direction of the electrode (main grid), the cutting position is the front surface or the back surface of the battery piece 1, and the cutting method is a combination of laser cutting and heat treatment. The laser cutting forms a damage zone 113 on the cutting surface 111, the damage zone 113 is located at both ends of the cutting line, and the length of the damage zone 113 along the extension direction of the cutting line is less than 1 cm. The extension direction of the electrode is in the same direction as the “first direction” indicated by the arrow in FIG. 5, and the cutting line extends along the “second direction” indicated by the arrow in FIG. 5, and the second direction is perpendicular to the first direction. By setting the cutting method as a combination of laser cutting and heat treatment, the damage zone 113 formed by the laser on the cutting surface 111 is located at both ends of the cutting line, and the length of the damage zone 113 along the extension direction of the cutting line is less than 1 cm. The damage zone 113 only occupies part of the region of one side of the battery piece, which can effectively reduce the influence of the damage zone 113 on the battery piece, thereby ensuring the performance of the battery piece.

[0052] It should be noted that the battery piece 1 refers to a half battery, which is cut from a whole battery, and the area of the two battery pieces 1 after cutting is equal. The cutting method is mostly laser cutting, and the use of laser often causes damage to the battery piece. The cutting surface formed by high-temperature laser cutting often has a high-temperature damage area. The damage depth of the damage area along the thickness direction of the battery piece is microns, and the damage depth is several microns to tens of microns. The damage cannot be ignored. The thickness refers to the distance between the front surface and the back surface of the battery piece, and the thickness direction refers to the "up and down" direction indicated by the arrow in FIG. 1.

[0053] Specifically, the laser cutting and heat treatment combined cutting method is a non-destructive method. That is, local laser cutting is performed at both ends of the whole battery, a small cut with a length less than 1 cm is cut out, and then the battery piece is naturally split along the line connecting the two cutouts through heat treatment by heating and rapid cooling. Since the length of the damage area 113 is less than 1 cm, the size is small, and the influence of the damage area 113 on the battery can be effectively reduced. When this method is used, according to the cutting requirements, the cutting can be performed on the front surface of the whole battery to form a damage area 113 as shown in FIGS. 5 to 6, or the cutting can be performed on the back surface of the whole battery (not shown in the figure), without considering the influence on the main PN junction.

[0054] In addition, in other embodiments, as shown in FIG. 7, the battery piece 1 is cut from a whole battery by laser cutting. The cutting line is perpendicular to the extension direction of the electrode, and the damage area 113 is formed on the cutting surface 111. The damage area 113 covers the entire cutting line, and the cutting position is the back surface of the battery piece 1. The extension direction of the electrode is in the same direction as the "first direction" indicated by the arrow in FIG. 7, and the cutting line extends along the "second direction" indicated by the arrow in FIG. 7. The battery piece 1 is directly cut from a whole battery by laser cutting. The cutting method is simple, easy to operate, and has high production efficiency. At the same time, by setting the cutting position on the back surface of the battery piece 1, the damage area 113 formed on the cutting surface 111 by laser cutting can be as far away from the PN junction 130 as possible, thereby reducing the influence on the PN junction and ensuring the quality of the battery piece 1. It should be noted that the cutting method by directly laser cutting is a destructive cutting method. That is, a line is cut in the middle of the whole battery by laser high-temperature cutting, so that the whole battery is divided into two half batteries. Therefore, the cutting needs to be performed at a position away from the PN junction 130, that is, the cutting needs to be performed on the back surface of the battery piece.

[0055] In one embodiment, the battery piece 1 is a rectangular or chamfered rectangular or square or chamfered square whole battery that is cut to form two half battery pieces.

[0056] In one embodiment, the front and back surfaces of the battery piece 1 are both covered with an isolation layer 101, which is an insulating material with light transmission. By covering the front and back surfaces of the battery piece 1 with the isolation layer 101, all surfaces of the battery piece 1 except the cutting surface 111 are covered with the isolation layer 101, which acts as a protective layer to protect the internal structure of the battery piece, isolate the positive and negative electrodes, reduce surface defects, reduce reflection, etc., to avoid the influence of external substances on the battery function, reduce electron recombination or leakage, thereby improving the performance of the battery piece. It should be noted that the isolation layer 101 is a protective film formed on the surface of the whole battery by high-temperature oxidation or plating. For the whole battery, all surfaces are covered with the isolation layer 101.

[0057] In one embodiment, the isolation layer 101 is composed of one or more of materials such as silicon dioxide, silicon nitride, and silicon oxynitride, which have good insulation and light transmission. The isolation material used in different positions of the isolation layer 101 on the battery piece 1 can be different.

[0058] In one embodiment, the number of positive electrodes 121 and negative electrodes 122 on each battery piece 1 is n, and the number of solder strips 2 connected to each battery piece 1 is n, where n is a positive integer greater than or equal to 8. Correspondingly, the number of solder strips connecting adjacent two battery pieces 1 is greater than or equal to 8, so that the connection between the battery pieces 1 is more intensive, which can more effectively collect and transmit current and improve the power generation efficiency.

[0059] It should be noted that the diameter of the solder strip 2 is getting smaller and smaller (the mainstream is 0.25mm diameter solder strip), the number of solder strips 2 is getting more and more (the mainstream is 16), the distance between adjacent battery pieces 1 is getting smaller and smaller (the mainstream is about 1.5mm), and even the soldering technology of more than 30 solder strips has appeared, the distance between battery pieces is also a large amount of <1mm, even 0 spacing or negative spacing, and the cross-sectional width of the solder strip diameter is micron level. The use of such extremely thin and extremely numerous solder strips greatly increases the risk of leakage caused by the overlap of the exposed PN junction 130 on the non-isolated local area (i.e. the cutting surface 111) of the battery piece 1 and the solder strip 2 or too close distance. The half-piece photovoltaic cell string of the present embodiment effectively improves the leakage or short circuit without increasing the process.

[0060] It should be noted that the above embodiments are described by taking N-type cells as an example, and in addition, the present embodiment can be applied to various photovoltaic cells.

[0061] According to the embodiment of the present application, the photovoltaic module further comprises a frame 3 and a laminated piece 4, the laminated piece 4 is installed in the frame 3, and the laminated piece 4 comprises the above-mentioned half-piece photovoltaic cell string. In the half-piece photovoltaic cell string welding process, by considering the structural characteristics of the cell piece 1, by setting the welding strip 2 away from the exposed PN junction, the performance of the cell after welding is improved, the defect conditions of the electric leakage or short circuit are improved, and the reliability and quality of the photovoltaic module are improved without increasing special process and cost. By integrating the cell piece structure, the slicing process and the welding strip connection process, a very efficient and reliable photovoltaic module structure is realized.

[0062] The frame 3 comprises an upper structure 301, a middle structure 302 and a lower structure 303 connected in sequence along the "up and down" direction indicated by the arrow in FIG. 9, the upper structure 301 has a clamping groove, and the laminated piece 4 is clamped in the clamping groove; the laminated piece 4 comprises a front glass plate, a laminated film, a photovoltaic cell, an interconnection material and a back glass plate, wherein the photovoltaic cell is the above-mentioned half-piece photovoltaic cell string, and the main power generation component of the laminated piece 4 is the photovoltaic cell, and the other packaging materials mainly play a role of light transmission and protection for the photovoltaic cell, that is, on the basis of ensuring that most of the light passes through the packaging material to reach the surface of the cell, the packaging material can also protect the photovoltaic cell in the photovoltaic module and prolong the life cycle of the photovoltaic module. The photovoltaic module realizes the interconnection and protection of the cell piece and realizes the long-term stable output of the photovoltaic cell.

[0063] The assembly process of the photovoltaic module is as follows:

[0064] First, the half-piece photovoltaic cells are interconnected, the assembly equipment moves from left to right along the track, drives the cell piece 1 to be placed from the left side, so that the left edge of each cell piece 1 contains the isolation layer 101, and the right edge is the cutting surface 111 without the isolation layer 101, the first welding section 201 of the welding strip 2 is arranged above the cell piece 1 located on the right side, and the second welding section 202 is arranged below the cell piece located on the left side, a plurality of cell pieces 1 are connected in sequence to form a half-piece photovoltaic cell string, and then the cell string is connected in series and parallel to form a power generation component in the module; then the front glass plate, the laminated film and the back glass plate are stacked in sequence; then the stacked product is placed in a laminator, the laminated material is melted by high temperature and vacuum of the laminator, and the gas in the laminated piece is discharged; after the lamination is completed, the overflowed laminated and residual materials are cut; and after the treatment, the laminated piece 4 is formed, and the frame mounting process (frame mounting process) is performed on the laminated piece 4. The frame mounting process needs to distribute glue (silicone) in the cavity of the special frame 3, and use a frame mounting machine to clamp and fix the frame 3 and the laminated piece 4.

[0065] While embodiments of the application have been described in connection with the preferred embodiments of the various figures, those of ordinary skill in the art will appreciate that various modifications and variations of the preferred embodiments can be employed without departing from the spirit and scope of the application.

Claims

1. A string of half-piece photovoltaic cells, characterized in that, The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module.

2. The bifacial photovoltaic cell string of claim 1, wherein, The application relates to a solar cell module.

3. The bifacial photovoltaic cell string of claim 2, wherein, The application relates to a solar cell module.

4. The bifacial photovoltaic cell string of claim 3, wherein, The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. 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The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a solar cell module. The application relates to a 5. The bifacial photovoltaic cell string of claim 3, wherein, Two adjacent battery pieces (1) are arranged with zero spacing, and several battery pieces (1) are arranged in a stepped manner, and the welding strip (2) is linear.

6. The bifacial photovoltaic cell string of claim 2, wherein, The battery piece (1) is cut from a whole battery, the cutting line is perpendicular to the extension direction of the electrode, the cutting position is the front surface or the back surface of the battery piece (1), the cutting method is a combination of laser cutting and heat treatment, the laser cutting forms a damage area (113) on the cutting surface (111), the damage area (113) is located at both ends of the cutting line, and the length of the damage area (113) along the extension direction of the cutting line is less than 1 cm.

7. The bifacial photovoltaic cell string of claim 2, wherein, The battery piece (1) is cut from a whole battery by laser cutting, the cutting line is perpendicular to the extension direction of the electrode, a damage area (113) is formed on the cutting surface (111), the damage area (113) covers the entire cutting line, and the cutting position is the back surface of the battery piece (1).

8. The bifacial photovoltaic cell string of claim 1, wherein, The front surface and the back surface of the battery piece (1) are covered with the isolation layer (101), and the isolation layer (101) is an insulating material with light transmission.

9. The bifacial photovoltaic cell string according to any of claims 1 to 8, characterized in that, The number of the positive electrode (121) and the negative electrode (122) on each battery piece (1) is n, and the number of the welding strip (2) connected to each battery piece (1) is n, wherein n is a positive integer greater than or equal to 8.

10. A photovoltaic module, characterized by, Comprise: A frame (3); A laminated piece (4) is installed in the frame (3), and the laminated piece (4) comprises the half-piece photovoltaic cell string according to any one of claims 1 to 9.

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