CN121240555A

CN121240555A - Back contact cells, back contact tandem cells and photovoltaic modules

Info

Publication number: CN121240555A
Application number: CN202511790097.5A
Authority: CN
Inventors: 孙玉峰; 王渊; 孔逸潇; 端伟元; 杨洁; 张昕宇
Original assignee: JinkoSolar Haining Co Ltd
Current assignee: JinkoSolar Haining Co Ltd
Priority date: 2025-12-01
Filing date: 2025-12-01
Publication date: 2025-12-30

Abstract

The application relates to the field of photovoltaics, and provides a back contact battery, a back contact laminated battery and a photovoltaic module, wherein a thin grid, a main grid and an insulating piece are arranged on the backlight surface of a body of the back contact battery; the thin grid comprises a first thin grid and a second thin grid, the insulating part covers the second thin grid, the main grid comprises main body parts and connecting parts which are alternately distributed in the second direction, the main body parts are located above the insulating part, the connecting parts are electrically connected with the first thin grid, the width of the connecting parts is larger than that of the main body parts, the connecting parts comprise connecting main bodies and protruding structures, and the protruding structures are located at least one end of the connecting main bodies in the first direction. The main grid structure can improve the connection strength of the main grid and the first fine grid, reduce the warping risk of the main grid or the main grid, save the slurry of the main grid and reduce the shading area of the main grid, thereby being beneficial to reducing the production cost of the back contact battery and improving the photoelectric conversion efficiency of the back contact battery.

Description

Back contact battery, back contact laminated battery and photovoltaic module

Technical Field

The application relates to the field of photovoltaics, in particular to a back contact battery, a back contact laminated battery and a photovoltaic module.

Background

The positive and negative grid lines of the back contact battery are arranged on the backlight surface of the back contact battery, the light-facing surface of the back contact battery is not shielded by the grid lines, and compared with a conventional photovoltaic battery, the back contact battery can reduce light energy loss caused by shielding of the grid lines and has higher photoelectric conversion efficiency. Wherein, the main grid and the thin grid with the same polarity are electrically connected, and the main grid and the thin grid with opposite polarity are insulated by an insulating piece.

Disclosure of Invention

In view of the above, the present application provides a back contact battery, a back contact stacked battery and a photovoltaic module, which are beneficial to solving the problem of insufficient connection reliability between a main grid and a thin grid with the same polarity in the prior art.

The application provides a back contact battery, which comprises a body, wherein a backlight surface of the body is provided with thin grids, a main grid and an insulating part, the thin grids extend along a first direction and comprise first thin grids and second thin grids which are alternately distributed along a second direction, the insulating part covers parts of the second thin grids, the main grid extends along the second direction and comprises main body parts and connecting parts which are alternately distributed along the second direction, the main body parts are positioned above the insulating part, the connecting parts are electrically connected with the first thin grids, the width of the connecting parts is larger than that of the main body parts in the first direction, the connecting parts comprise connecting bodies and protruding structures, the protruding structures are positioned at least one end of the connecting bodies along the first direction, and the first direction is intersected with the second direction.

In one possible implementation, the protruding structure is provided with a notch portion recessed inwardly in the first direction.

In one possible implementation, at least part of the first fine grid is located within the notch portion.

In one possible implementation manner, the protruding structure includes at least two protruding portions arranged along the second direction, and the notch portion is formed between two adjacent protruding portions.

In one possible implementation manner, the protruding structure comprises two protruding parts, the two protruding parts are respectively located at two sides of the first fine grid along the second direction, and the lengths of the two protruding parts in the second direction are equal.

In one possible implementation, along the first direction, the width W1 of the connecting body and the width W2 of the connecting portion satisfy 1.1:1+.w2:w1+.2:1.

In one possible implementation manner, the protruding structures are arranged on two sides of the connecting main body along the first direction, and the widths of the two protruding structures in the first direction are equal.

In one possible implementation manner, the width W2 of the connection portion and the width W3 of the insulating member in the first direction satisfy 1:5+.w2:w3+.3:7.

In one possible implementation, along the second direction, the width D1 of the second fine grid and the length L1 of the insulating member and the length D1 of the insulating member are equal to or greater than 1:10.

In one possible implementation manner, the main grid comprises a first section, a second section and a third section, the second section and the third section are respectively and electrically connected with two ends of the first section along the second direction, and at least one of the second section and the third section is in a harpoon structure.

In one possible implementation, the first, second and third sections are each provided with the body portion and the connection portion.

In a second aspect, the application provides a back contact laminated cell, which comprises a back contact bottom cell and a perovskite top cell, wherein the perovskite top cell is electrically connected with a light facing surface of the back contact bottom cell, and the back contact bottom cell is the back contact cell.

The application provides a photovoltaic module, which comprises a plurality of photovoltaic cells, wherein the photovoltaic cells are back contact batteries or back contact laminated electricity, and welding strips, wherein two adjacent photovoltaic cells along the second direction are connected through the welding strips in an electric property mode.

The application has the beneficial effects that the first fine grid is intersected with the main grid and is electrically connected with the main grid, and the second fine grid and the main grid are arranged in an insulating way through the insulating piece. In the first direction, the width of the connecting part is larger than that of the main body part, so that the connecting area of the main grid and the first fine grid is increased, and the connecting strength and the connecting reliability of the main grid and the first fine grid are improved. When the connecting area of the connecting part and the first fine grid is larger, the stress between the connecting part and the body can be effectively dispersed, and the risk of warping of the body or the main grid can be reduced. The main grid and the first fine grid are provided with higher connection strength, so that the back contact battery can bear larger mechanical stress when being laminated to form the photovoltaic module, the tensile strength of the photovoltaic module can be improved, and the service life of the photovoltaic module can be prolonged. The structure of the main grid provided by the application can also increase the connection area between the main grid and the welding strip, so that the tensile force between the main grid and the welding strip is improved, and the connection strength and the connection reliability of the back contact battery and the welding strip are improved. In addition, the width of the connecting part of the main grid is larger than that of the main body part, so that the main grid has a locally widened structure, compared with the whole widened structure of the main grid, the slurry of the main grid can be saved, the shading area of the main grid is reduced, the production cost of the back contact battery is reduced, the optical utilization efficiency of the backlight surface of the back contact battery is improved, and the photoelectric conversion efficiency and the output power of the back contact battery are improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic view of a partial structure of a back surface of a back contact battery according to an embodiment of the present application;

FIG. 2 is a schematic view of a partial structure of the back contact battery in FIG. 1 in a first embodiment;

FIG. 3 is a schematic view of a partial structure of the back contact battery in FIG. 1 in a second embodiment;

FIG. 4 is a schematic view of a partial structure of the back contact battery in FIG. 1 in a third embodiment;

FIG. 5 is a schematic view showing a partial structure of the back contact battery in FIG. 1 in a fourth embodiment;

fig. 6 is a schematic structural diagram of a backlight surface of a first back contact battery according to an embodiment of the present application;

Fig. 7 is a schematic structural diagram of a second back-contact cell backlight surface according to an embodiment of the present application;

FIG. 8 is a schematic view of the main gate of FIG. 7;

Fig. 9 is a schematic view of a partial cross-sectional structure of a back contact battery according to an embodiment of the present application;

fig. 10 is a schematic structural diagram of a back contact stacked cell according to an embodiment of the present application;

Fig. 11 is a schematic structural diagram of a photovoltaic module according to a first embodiment of the present application;

fig. 12 is a schematic structural diagram of a photovoltaic module according to a second embodiment of the present application.

Reference numerals:

10-back contact cell;

101-a substrate;

101 a-a first surface;

101 b-a second surface;

101 ba-first region;

101 bb-a second region;

102-tunneling oxide;

a 103-N type doped polysilicon layer;

104-a first transparent conductive layer;

105-a first electrode;

106-an intrinsic amorphous silicon layer;

107-P type doped amorphous silicon layer;

108-a second transparent conductive layer;

109-a second electrode;

1010-an antireflection layer;

1011-passivation layer;

20-back contact laminate cell;

201-back contact bottom cell;

202-perovskite top cell;

30-welding the tape;

40-front plate;

50-front side encapsulation layer;

60-a backside encapsulation layer;

70-a back plate;

1-a body;

2-fine grid;

21-a first fine grid;

21' -a first positive fine grid;

21 "-a first negative fine grid;

22-a second fine grid;

22' -a second negative electrode fine grid;

22' -a second positive fine grid;

3-an insulator;

4-main grid;

4 a-a first section;

4 b-a second section;

4 ba-a first confluence part;

4 bb-a second confluence section;

4 c-third section;

4 ca-a third confluence part;

4 cb-a fourth confluence part;

401-a first main gate;

402-a second main gate;

41-a main body portion;

41 a-a first body portion;

41 b-a second body portion;

41 c-a third body portion;

42-connecting part;

42 a-a first connection;

42 b-a second connection;

42 c-a third connection;

421-connecting a body;

421 a-a first connecting body;

421 b-a second connecting body;

421 c-a third connecting body;

422-bump structure;

422A-first bump structure;

422B-a second bump structure;

422C-third bump structure;

422 a-notch portion;

422 Aa-a first notch portion;

422 Ba-second notch portion;

422 Ca-third notch;

422 b-a boss;

422 Ab-first boss;

422 Bb-second boss;

422 Cb-third lobe;

5-edge gate lines.

Detailed Description

For a better understanding of the technical solution of the present application, the following detailed description of the embodiments of the present application refers to the accompanying drawings.

It should be understood that the described embodiments are merely some, but not all, embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely an association relationship describing the associated object, and means that three relationships may exist, for example, a and/or b, and may mean that a single first exists while a single first and a single second exist. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

It should be noted that, the terms "upper", "lower", "left", "right", and the like in the embodiments of the present application are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present application. In the context of this document, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on the other element or be indirectly on the other element through intervening elements.

The embodiment of the present application provides a back contact battery 10, as shown in fig. 1, the back contact battery 10 includes a body 1, a backlight surface of the body 1 is provided with a fine grid 2, an insulating member 3 and a main grid 4, the fine grid 2 includes first fine grids 21 and second fine grids 22 alternately distributed in a second direction Y, and the first fine grids 21 and the second fine grids 22 each extend along a first direction X for collecting and guiding a photo-generated current generated in the body 1. The first and second thin grids 21 and 22 have opposite polarities, one of which is a positive thin grid of the back contact cell 10 and the other of which is a negative thin grid of the back contact cell 10. The main grid 4 extends along the second direction Y, the polarity of the first fine grid 21 is the same as that of the main grid 4, and the first fine grid 21 intersects with the main grid 4 and forms an electrical connection, so that the main grid 4 can collect and output the photo-generated current collected by the first fine grid 21 outwards. The polarity of the second fine grid 22 is opposite to that of the main grid 4, and the second fine grid 22 and the main grid 4 are arranged in an insulating manner along the height direction Z of the back contact battery 10 through an insulating piece 3, wherein the insulating piece 3 covers part of the surface of the second fine grid 22, the main grid 4 is arranged above the insulating piece 3, and isolation and insulation between the main grid 4 and the second fine grid 22 are realized through the insulating piece 3 so as to avoid short circuit caused by electric connection between the second fine grid 22 and the main grid 4. The insulating element 3 may be, in particular, a printed insulating glue.

As shown in fig. 1, one of the first direction X and the second direction Y may be the longitudinal direction of the back contact battery 10, and the other may be the width direction of the back contact battery 10.

The present application provides the drawings in which lines of different thicknesses are used to distinguish between the first fine grid 21 and the second fine grid 22, which is not a limitation on the relative widths between the first fine grid 21 and the second fine grid 22, and the widths of the first fine grid 21 and the second fine grid 22 may be equal or unequal.

As shown in fig. 1 and 2, in a specific embodiment, the main grid 4 includes main body portions 41 and connection portions 42 alternately distributed in the second direction X, the main body portions 41 being located above the insulating member 3 for forming an insulating arrangement with the second fine grid 22, and the connection portions 42 being located above the first fine grid 21 for electrically connecting with the first fine grid 21. In the first direction X, the width of the connection portion 42 is larger than the width of the main body portion 41, which is advantageous for increasing the connection area of the main grid 4 and the first fine grid 21, thereby improving the connection strength and connection reliability of the main grid 4 and the first fine grid 21. When the connection area of the connection portion 42 and the first fine grid 21 is large, the stress between the connection portion 42 and the body 1 can be effectively dispersed, and the risk of warpage of the body 1 or the main grid 4 can be reduced. The higher connection strength between the main grid 4 and the first fine grid 21 can ensure that the back contact battery 10 can bear larger mechanical stress when being laminated into a photovoltaic module, can also ensure that the tensile strength of the prepared photovoltaic module is improved, and is beneficial to prolonging the service life of the photovoltaic module.

The structure of the main grid 4 provided in this embodiment can also increase the connection area between the main grid 4 and the solder strip, so as to increase the tensile force between the main grid 4 and the solder strip, and thus increase the connection strength and connection reliability of the back contact battery 10 and the solder strip. In addition, the width of the connection portion 42 of the main gate 4 is greater than the width of the main body portion 41, so that the main gate 4 has a locally widened structure, and compared with the integrally widened structure of the main gate 4, the slurry of the main gate 4 can be saved, and the shading area of the main gate 4 can be reduced, thereby being beneficial to reducing the production cost of the back contact battery 10, improving the optical utilization efficiency of the backlight surface of the back contact battery 10, and further being beneficial to improving the photoelectric conversion efficiency and the output power of the back contact battery 10.

Further, as shown in fig. 2, the connection portion 42 includes a connection body 421 and a bump structure 422, and the width of the connection body 421 in the first direction X is identical to the width of the body portion 41 in the first direction X, so that the conductivity of the entire main gate 4 is ensured to be identical. The protruding structure 422 is located at least one end of the connection body 421 in the first direction X to have an effect of increasing the width of the connection portion 42. The protruding structure 422 is provided with a notch portion 422a recessed inwards along the first direction X, and by providing the notch portion 422a, the slurry of the main grid 4 can be further saved and the light shielding area of the main grid 4 can be reduced, so that the production cost of the back contact battery 10 can be further reduced, and the optical utilization efficiency of the backlight surface of the back contact battery 10 can be further improved. On the other hand, by providing the notch 422a, the effect of dispersing stress in the connection portion 42 can be further improved, and stress between the connection portion 42 and the first fine grid 21 can be transmitted along the side wall of the notch 422a, so that the risk of stress concentration at the connection portion of the connection portion 42 and the first fine grid 21 is reduced.

The width of the connecting portion 42 described above refers to the maximum width of the connecting portion 42 in the first direction X, and similarly, when the widths of the main portions 41 are not identical, the width of the main portions 41 refers to the maximum width of the main portions 41 in the first direction X.

In a specific embodiment, as shown in fig. 2, along the first direction X, the width W1 of the connecting body 421 and the width W2 of the connecting portion 42 satisfy that 1.1:1+.w2:w1+.2:1, that is, the connecting body 421 can be widened by 10% -100% by providing the protruding structure 422. When W1 and W2 satisfy the above range, the width W2 of the connection portion 42 is moderate in size, and neither too small a connection area of the connection portion 42 and the first fine grating 21 nor too large a waste of slurry is caused. Therefore, when W1 and W2 are 1.1:1≤W2:1≤2:1, not only can the connection area between the connection part 42 and the first fine grid 21 and the connection part 42 and the solder strip be ensured to improve the connection strength between the main grid 4 and the first fine grid 21 and the connection strength between the main grid 4 and the solder strip, but also the risk of warping of the main grid 4 or the main grid 1 can be reduced, the slurry of the main grid 4 can be saved, the shading area of the main grid 4 can be reduced, the production cost of the back contact battery 10 can be reduced, and the photoelectric conversion efficiency of the back contact battery 10 can be improved.

It is to be understood that, in the present embodiment, the dimension of the width W1 of the connecting body 421 and the width W2 of the connecting portion 42 need to satisfy the above-mentioned range, whether the connecting body 421 has the protruding structure 422 on one side or the protruding structure 422 on both sides. When the protruding structures 422 are disposed on both sides of the connection body 421, the widths of the protruding structures 422 on both sides in the first direction X may be equal or different, which is not limited in this embodiment.

Alternatively, the ratio of W2 to W1 may be 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, or other values within the above range, which is not limited in this embodiment.

In a specific embodiment, as shown in fig. 2, at least part of the first fine grid 21 is located in the notch 422a, that is, a portion where the projection of the notch 422a along the height direction Z of the back contact cell 10 coincides with the projection of the first fine grid 21 along the height direction Z of the back contact cell 10. The above structure enables the connecting portion 42 and the first fine grid 21 to form an interlocking structure, and both side walls of the notch portion 422a have a stopper effect on the first fine grid 21 in the second direction Y. On the other hand, the preparation sequence of the back contact battery 10 is that the thin grid 2 is printed on the body 1, then the insulating piece 3 is printed, and finally the main grid 4 is printed, when the structure that the notch 422a corresponds to the first thin grid 21 is adopted, the main grid 4 is convenient to print, and whether the position of the notch 422a for printing the glue mesh on the printing screen corresponds to the position of the first thin grid 21 on the body 1 or not can be judged quickly, so that the positioning of the glue screen is accurate or not, and the improvement of the printing efficiency and the printing precision of the main grid 4 is facilitated, thereby being beneficial to the improvement of the production efficiency of the back contact battery 10.

In a specific embodiment, as shown in fig. 2, the protruding structure 422 includes at least two protruding portions 422b arranged along the second direction Y, a gap portion 422a is formed between two adjacent protruding portions 422b, specifically, a gap is formed between outer contours of two adjacent protruding portions 422b along the second direction Y, and the gap portion 422a is formed by the gap. That is, in the present embodiment, the notch portion 422a is formed by the outer contour structure of the protruding portion 422b, and the protruding portion 422b may be, specifically, a semicircular shape (shown in fig. 2), a triangular shape (shown in fig. 3), a trapezoid shape (shown in fig. 4), or other structures, which is not limited in this embodiment.

In the present embodiment, the outer contour shapes of the plurality of protruding portions 422b constituting the protruding structure 422 may be the same or different, and the present embodiment is not limited thereto. The protrusion structure 422 may include 2, 3, 4, 5, 6, or more protrusions 422b, which is not limited in this embodiment.

In the first specific embodiment, as shown in fig. 2, the protruding structure 422 includes only two protruding portions 422b, and the two protruding portions 422b are located on two sides of the first fine grid 21 along the second direction Y, so as to ensure that the first fine grid 21 can be located on the notch portion 422a. In this embodiment, in order to ensure that the connection area of the bump structure 422 and the first fine grating 21 is sufficiently large, two bump portions 422b should be continuously disposed and connected to each other in the second direction Y. The lengths of the two protrusions 422b in the second direction Y may be equal or different.

Preferably, the lengths of the two protruding portions 422b in the second direction Y are equal, i.e. the two protruding portions 422b are symmetrically distributed on both sides of the first fine grid 21 along the second direction Y, so that it is ensured that the force applied to the first fine grid 21 is uniform, and the risk of stress concentration at the connection between the protruding structure 422 and the first fine grid 21 is reduced. Moreover, when the lengths of the two protrusions 422b are equal, the shrinkage degree of the two protrusions 422b is uniform during the slurry sintering and cooling process, which is beneficial to reducing the risk of buckling deformation of the body 1. In addition, the symmetrical structure can reduce the difficulty of the printing process of the protruding structure 422, which is beneficial to improving the production efficiency of the back contact battery 10.

It should be noted that, in the actual manufacturing process of the back contact battery 10, it is difficult to ensure that the lengths of the two protruding portions 422b in the second direction Y are equal in absolute terms, and therefore, as long as the actual measurement values of the lengths of the two protruding portions 422b in the second direction Y are within a certain error range, it can be regarded that the lengths of the two protruding portions 422b in the second direction Y are equal. The error range may be determined according to an actual manufacturing process, an actual measuring tool, and an actual design requirement of the boss 422b, which is not limited in this embodiment.

In the second specific embodiment, the bump structure 422 includes three or more bumps 422b, and the bumps 422b are continuously disposed and sequentially connected in the second direction Y, so as to ensure that the connection area between the bump structure 422 and the first fine grid 21 is sufficiently large. The length of each boss 422b in the second direction Y may or may not be equal. Preferably, as shown in fig. 5, the number of the protruding portions 422b is two, the length of each protruding portion 422b in the second direction Y is equal, and the protruding portions 422b are symmetrically distributed on two sides of the first fine grid 21 along the second direction Y, so that the force applied to the first fine grid 21 can be ensured to be uniform, and the risk of stress concentration at the connection part of the protruding structure 422 and the first fine grid 21 is reduced. Moreover, when the protruding portions 422b are symmetrically distributed on both sides of the first fine grid 21 along the second direction Y, the shrinkage degree of the protruding portions 422b on both sides of the first fine grid 21 is uniform during the slurry sintering and cooling process, which is beneficial to reducing the risk of buckling deformation of the body 1.

In a specific embodiment, as shown in fig. 2, the length L2 of the bump structure 422 in the second direction Y is 500 μm to 1000 μm. If L2 is too small (for example, less than 500 μm), the area of the entire bump structure 422 is too small, which results in insufficient connection strength between the main grid 4 and the first fine grid 21 and insufficient connection strength between the main grid 4 and the solder strip. If L2 is too large (for example, greater than 1000 μm), the area of the entire bump structure 422 is too large, which results in an increase in the light shielding area of the main gate 4 and also causes waste of paste. Therefore, when the length L2 of the bump structure 422 in the second direction Y is 500 μm to 1000 μm, it is not only able to ensure that the main grid 4 has sufficient connection strength with the first fine grid 21 and the main grid 4 and the solder strip, but also able to save the slurry of the main grid 4 and reduce the light shielding area of the main grid 4, thereby being beneficial to reducing the production cost of the back contact battery 10 and improving the optical utilization efficiency of the back surface of the back contact battery 10, and further beneficial to improving the photoelectric conversion efficiency and output power of the back contact battery 10.

Alternatively, L2 may be 500 μm to 800. Mu.m, specifically 500 μm, 520 μm, 550 μm, 580 μm, 600 μm, 620 μm, 650 μm, 680 μm, 700 μm, 720 μm, 750 μm, 780 μm or 800 μm, or other values within the above range, which is not limited in this embodiment.

Alternatively, L2 may be 800 μm to 1000 μm, specifically 800 μm, 820 μm, 850 μm, 880 μm, 900 μm, 920 μm, 950 μm, 980 μm or 100 μm, or may be other values within the above range, which is not limited in this embodiment. In a specific embodiment, as shown in fig. 2, the connection body 421 is provided with protruding structures 422 on two sides along the first direction X, and the widths of the two protruding structures 422 in the first direction X are equal, that is, the two protruding structures 422 are symmetrically distributed on two sides of the connection body 421, so that the stress of the connection portion 42 in the first direction X is more uniform. Moreover, when the widths of the two bump structures 422 in the first direction X are equal, the shrinkage degree of the two bump structures 422 is also uniform during the slurry sintering and cooling process, which is beneficial to reducing the risk of buckling deformation of the body 1. In addition, the symmetrical structure can reduce the difficulty of the printing process of the connecting part 42, which is beneficial to improving the production efficiency of the back contact battery 10.

It should be noted that, in the actual manufacturing process of the back contact battery 10, it is difficult to ensure that the widths of the two protruding structures 422 in the first direction X are equal in absolute terms, so as long as the actual measurement values of the widths of the two protruding structures 422 in the first direction X are within a certain error range, it can be regarded that the widths of the two protruding structures 422 in the first direction X are equal. The error range may be determined according to an actual manufacturing process, an actual measuring tool, and an actual design requirement of the bump structure 422, which is not limited in this implementation.

In a specific embodiment, as shown in fig. 2, along the first direction X, the width W2 of the connection portion 42 and the width W3 of the insulating member 3 satisfy the interval of 1:5+.w2:w3+.3:7, i.e. the ratio of W2 to W3 satisfies the interval of 1:5 to 3:7.

If the ratio of W2 to W3 is too small (e.g. less than 1:5), there are two cases that W2 is too small or W3 is too large, when W2 is too small, the connection reliability of the connection portion 42 and the first fine grid 21 is insufficient and the connection reliability of the connection portion 42 and the solder strip is insufficient, and when W3 is too large, the raw material of the insulating member 3 is wasted, resulting in an increase in the production cost of the back contact battery 10. If the ratio of W2 to W3 is too large (e.g. greater than 3:7), there are two cases that W2 is too large or W3 is too small, when W2 is too large, the slurry of the connection portion 42 is wasted, resulting in an increase in the production cost of the back contact battery 10, and also resulting in an increase in the light shielding area of the main grid 4, resulting in a decrease in the photoelectric conversion efficiency of the back contact battery 10, and when W3 is too small, once the main grid 4 shifts during printing, the main grid 41 and the second fine grid 22 are easily electrically connected, and the solder strip electrically connected with the main grid 41 is also easily electrically connected with the second fine grid 22, resulting in a short circuit of the back contact battery 10. Therefore, when W2 and W3 are 1:5≤W2:3≤3:7, not only can the connection area between the connection part 42 and the first fine grid 21 and the connection part 42 and the solder strip be ensured to improve the connection strength between the main grid 4 and the first fine grid 21 and the connection strength between the main grid 4 and the solder strip, but also the risk of warping of the main grid 1 or the main grid 4 can be reduced, the slurry of the main grid 4 can be saved, the shading area of the main grid 4 can be reduced, the raw material of the insulating member 3 can be saved, the production cost of the back contact battery 10 can be reduced, the photoelectric conversion efficiency of the back contact battery 10 can be improved, and the risk of short circuit of the back contact battery 10 can be reduced.

Alternatively, the ratio of W2 to W3 may be 1:5, 1:4, 2:7, 1:3, 2:5 or 3:7, or may be other values within the above range, which is not limited in this embodiment.

In a specific embodiment, as shown in FIG. 2, along the second direction Y, the width D1 of the second fine grid 22 and the length L1 and the length D1 of the insulating member 3 are equal to or greater than 1:10. If the ratio of D1 to L1 is too small (e.g. less than 1:10), the raw material of the insulating member 3 is wasted, resulting in an increase in the cost of the back contact battery 10, and the insulating member 3 may contact the connection portion 42 to affect the reliability of the electrical connection between the connection portion 42 and the first fine grid 21. Therefore, when D1 and L1 are equal to or greater than or equal to 1:10, the reliability of the electrical connection between the connection portion 42 and the first fine grid 21 can be ensured, and the production cost of the back contact battery 10 can be reduced.

Alternatively, the ratio of D1 to L1 may be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 3:10, 1:3, 2:5, or 1:2, or may be other values within the above range, which is not limited in this embodiment.

The schematic structural diagram of the first back contact battery 10 provided in the embodiment of the present application is shown in fig. 6, where the main grid 4 is a vertical structure extending along the second direction Y.

The schematic structural diagram of the second back contact battery 10 provided in the embodiment of the present application is shown in fig. 7, where, in conjunction with fig. 8, the main grid 4 includes a first section 4a, a second section 4b and a third section 4c, and along the second direction Y, the second section 4b and the third section 4c are respectively electrically connected to two ends of the first section 4a, and at least one of the second section 4b and the third section 4c is in a fish fork structure.

In this embodiment, the first section 4a is used to form an electrical connection with the solder strip, and the second section 4b and the third section 4c are used to collect the current on the first fine grid 21 at the edge of the battery. When the second section 4b is of a harpoon structure, the second section 4b has first converging portions 4ba and second converging portions 4bb distributed at intervals along the first direction X, and the first converging portions 4ba and the second converging portions 4bb are electrically connected with the first section 4 a. The first converging portion 4ba and the second converging portion 4bb can respectively collect currents on the plurality of first thin grids 21, so that the collection capability of the second section 4b on the first thin grids 21 located at the edge positions of the battery is improved, and the photoelectric conversion efficiency of the back contact battery 10 is improved. When one of the first and second bus portions 4ba and 4bb fails, the other can also function normally, thereby contributing to improvement of structural stability and electrical reliability of the second segment 4 b. Similarly, when the third section 4c is of a harpoon structure, the third section 4c has third and fourth converging portions 4ca and 4cb distributed at intervals along the first direction X, and the third and fourth converging portions 4ca and 4cb are electrically connected to the first section 4 a. The third current collecting portion 4ca and the fourth current collecting portion 4cb can collect the currents on the plurality of first thin grids 21, so that the collection capability of the third section 4c on the first thin grids 21 located at the edge position of the battery is improved, and the photoelectric conversion efficiency of the back contact battery 10 is improved. When one of the third and fourth bus portions 4ca and 4cb fails, the other can also function normally, thereby contributing to improvement of structural stability and electrical reliability of the second segment 4 b.

Therefore, when the second section 4b and the third section 4c are both of a harpoon structure, it is advantageous to further improve the structural stability and electrical reliability of the main grid 4, and to improve the photoelectric conversion efficiency of the back contact battery 10.

In a specific embodiment, at least one of the first, second and third sections 4a, 4b, 4c is provided with a body portion 41 and a connecting portion 42, preferably the first, second and third sections 4a, 4b, 4c are each provided with a body portion 41 and a connecting portion 42.

Specifically, as shown in fig. 8, when the first, second, and third segments 4a, 4b, and 4c are each provided with the body portion 41 and the connection portion 42, the first segment 4a includes the first body portions 41a and the first connection portions 42a alternately distributed in the second direction Y, and the width of the first connection portion 42a is larger than the width of the first body portion 41 a. The first connection part 42A includes a first connection body 421a and a first protrusion structure 422A, the first protrusion structure 422A may be provided with a first notch part 422Aa recessed inward in the first direction X, and the first protrusion structure 422A may include at least two first protrusion parts 422Ab arranged in the second direction Y. The width ratio between the first connecting body 421a and the first connecting portion 42A, the specific structure and dimensions of the first protruding structure 422A and the first protruding portion 422Ab, and the width ratio between the first connecting portion 42A and the insulating member 3 can refer to the descriptions of the connecting portion 42, the connecting body 421, the protruding structure 422, the protruding portion 422b and the notch portion 422A, which are not repeated herein.

When the first, second and third segments 4a, 4b and 4c are each provided with the body portion 41 and the connection portion 42, the second segment 4b includes the second body portions 41b and the second connection portions 42b alternately distributed in the second direction Y, and the width of the second connection portion 42b is greater than the width of the second body portion 41 b. The second connection part 42B includes a second connection body 421B and a second protrusion structure 422B, the second protrusion structure 422B may be provided with a second notch part 422Ba recessed inward in the first direction X, and the second protrusion structure 422B may include at least two second protrusion parts 422Bb arranged in the second direction Y. The width ratio between the second connecting body 421B and the second connecting portion 42B, the specific structure and dimensions of the second protruding structure 422B and the second protruding portion 422Bb, and the width ratio between the second connecting portion 42B and the insulating member 3 can refer to the descriptions of the connecting portion 42, the connecting body 421, the protruding structure 422, the protruding portion 422B and the notch portion 422a, which are not repeated herein.

When the first, second and third segments 4a, 4b, 4c are each provided with the body portion 41 and the connection portion 42, the third segment 4c includes the third body portions 41c and the third connection portions 42c alternately distributed in the second direction Y, and the width of the third connection portion 42c is larger than the width of the third body portion 41 c. The third connection part 42C includes a third connection body 421C and a third protrusion structure 422C, the third protrusion structure 422C may be provided with a third notch part 422Ca recessed inward in the first direction X, and the third protrusion structure 422C may include at least two third protrusion parts 422Cb arranged in the second direction Y. The width ratio between the third connecting body 421C and the third connecting portion 42C, the specific structure and dimensions of the third protruding structure 422C and the third protruding portion 422Cb, and the width ratio between the third connecting portion 42C and the insulating member 3 can refer to the descriptions of the connecting portion 42, the connecting body 421, the protruding structure 422, the protruding portion 422b and the notch portion 422a, which are not repeated herein. As shown in fig. 6 and 7, for the back contact battery 10, the main gate 4 includes a first main gate 401 and a second main gate 402, one of the first main gate 401 and the second main gate 402 being a positive main gate, and the other being a negative main gate. In this embodiment, the specific structure of the back contact battery 10 is described in detail by taking the first main grid 401 as the positive electrode main grid and the second main grid 402 as the negative electrode main grid as examples, wherein the first thin grid 21 electrically connected with the first main grid 401 is the first positive electrode thin grid 21', the second thin grid 22 insulated from the first main grid 401 by the insulating member 3 is the second negative electrode thin grid 22', and the first positive electrode thin grid 21 'and the second negative electrode thin grid 22' are alternately distributed in the second direction Y. The first thin gate 21 electrically connected to the second main gate 402 is a first negative thin gate 21", the second thin gate 22 insulated from the second main gate 402 by the insulating member 3 is a second positive thin gate 22", and the first negative thin gate 21 "and the second positive thin gate 22" are alternately distributed in the second direction Y. In the first direction X, the first positive electrode fine grid 21 'and the second positive electrode fine grid 22 "are integrally formed, and it is also understood that the first positive electrode fine grid 21' and the second positive electrode fine grid 22" are two adjacent regions on the positive electrode fine grid. Along the first direction X, the second negative electrode fine grid 22 'and the first negative electrode fine grid 21 "are integrally formed, which may be understood as that the second negative electrode fine grid 22' and the first negative electrode fine grid 21" are two adjacent regions on the negative electrode fine grid.

As shown in fig. 6, the back contact battery 10 is further provided with edge grid lines 5 at both ends in the first direction X, the edge grid lines 5 extending in the second direction Y. The polarity of the edge grid line 5 is opposite to the polarity of the adjacent main grid 4, and is used for forming electric connection with the fine grid 2 interrupted by the main grid 4 so as to collect the current collected by the interrupted fine grid 2, thereby improving the efficiency of the back contact battery 10. The polarities of the two edge gate lines 5 respectively located at the two ends of the back contact battery 10 along the first direction X may be the same or opposite, which is not limited in this embodiment.

In some embodiments, the type of back contact cell 10 may be one of an interdigitated back contact cell (INTERDIGITATED BACK CONTACT, IBC), a heterojunction back contact cell (Heterojunction Back Contact, HBC), a tunnel oxide back contact cell (Tunnel Oxide Back Contact, TBC). For the IBC battery, the IBC battery sequentially comprises a silicon nitride passivation layer, an N+ front surface field, an N-type substrate silicon layer, a P+ emitter, an N+ back field, an aluminum oxide passivation layer, a silicon nitride anti-reflection layer and a metal silver electrode along the thickness direction of the IBC battery. The IBC battery can obtain a P region and an N region which are good in uniformity and accurate and controllable in junction depth by using an ion implantation technology, the front surface of the battery is free of grid line shielding, shading current loss of a metal electrode can be eliminated, maximum utilization of incident photons is achieved, short-circuit current of the IBC battery can be improved by about 7% compared with that of a conventional solar battery, the grid line shielding problem is not needed to be considered due to a back contact structure, the proportion of the grid line can be properly widened, series resistance is reduced, the filling factor is high, and the optimization design of surface passivation and surface light trapping structures can be carried out, so that lower front surface recombination rate and surface reflection can be obtained.

For the HBC battery, the advantages of the IBC battery and the heterojunction battery are well combined, the passivation layer on the front surface of the HBC battery adopts hydrogenated amorphous silicon, and the amorphous silicon films of N type and P type are respectively deposited on the back surface of the HBC battery to form a heterojunction. The HBC battery fully utilizes the superior surface passivation performance of amorphous silicon, and the heterojunction structure formed on the back has a good passivation effect, and can obtain higher large short-circuit current and open-circuit voltage at the same time, so that the photoelectric conversion efficiency is improved.

For a TBC battery, the TBC battery has the advantages of a tunneling oxide layer technology of Topcon and an IBC back surface electrode arrangement, the passivation effect and the open circuit voltage are obviously improved, and the battery conversion efficiency is higher and meanwhile the economy is realized. The complete production process of the TBC battery mainly comprises the steps of depositing a tunneling oxide layer and P+ polysilicon, depositing a passivation film, printing an electrode on the back surface of a silicon wafer and the like. On the basis of TOPCon production processes, the TBC battery needs to be added with related processes of a mask, laser grooving, PN region preparation, etching and the like, the mask is mainly finished by APCVD or PECVD, the PN region preparation is mainly finished by PECVD, the etching is mainly finished by adopting traditional wet equipment, and the grooving process needs to be finished by laser equipment.

The embodiment of the present application provides a structure of a back contact cell 10, as shown in fig. 9, the back contact cell 10 is a hybrid back contact cell employing a tunnel oxide layer 121 passivation contact cell technology and a heterojunction cell technology. Specifically, the back contact cell 10 has a substrate 101, and the substrate 101 may be a silicon substrate including, but not limited to, a monocrystalline silicon substrate, a polycrystalline silicon substrate, a microcrystalline silicon substrate, a nanocrystalline silicon substrate, and the like. The doping element In the substrate 101 may be an N-type dopant including a V-group element such As phosphorus (P), arsenic (As), bismuth (Bi), antimony (Sb), or a P-type dopant including a III-group element such As boron (B), aluminum (Al), gallium (Ga), indium (In). The substrate 101 has a first surface 101a and a second surface 101b that are relatively distributed along a height direction Z, where the first surface 101a may be a light-facing surface of the substrate 101, i.e. a surface facing the light source and configured to receive direct sunlight, and the second surface 101b may be a backlight surface of the substrate 101, i.e. a surface facing away from the light source and configured to receive sunlight reflected by the ground. Both the first surface 101a and the second surface 101b can receive sunlight and convert the light energy into electric energy.

The second surface 101b comprises first regions 101ba and second regions 101bb alternately arranged along the first direction X, one of the first regions 101ba and the second regions 101bb being provided with a tunneling passivation contact structure, the other being provided with a heterojunction contact structure. Specifically, as shown in fig. 9, the tunneling passivation contact structure may include a tunneling oxide layer 102 and an N-doped polysilicon layer 103, where the N-doped polysilicon layer 103 is located on a side of the tunneling oxide layer 102 facing away from the substrate 101, a first transparent conductive layer 104 is disposed on a side of the N-doped polysilicon layer 103 facing away from the substrate 101, the first transparent conductive layer 104 is a TCO layer, and a first electrode 105 is disposed on the first transparent conductive layer 104 and electrically connected to the tunneling passivation contact structure. The heterojunction contact structure may include an intrinsic amorphous silicon layer 106 and a P-type doped amorphous silicon layer 107, the P-type doped amorphous silicon layer 107 is located on a side of the intrinsic amorphous silicon layer 106 away from the substrate 101, a second transparent conductive layer 108 is disposed on a side of the P-type doped amorphous silicon layer 107 away from the substrate 101, the second transparent conductive layer 108 is a TCO layer, and the second electrode 109 is disposed on the second transparent conductive layer 108 and electrically connected to the heterojunction contact structure. The first transparent conductive layer 104 and the second transparent conductive layer 108 are spaced apart in the first direction X, and the first transparent conductive layer 104 and the second transparent conductive layer 108 have excellent lateral conductivity. Due to the poor transverse conductivity of the P-type doped amorphous silicon layer 107, the first transparent conductive layer 104 and the second transparent conductive layer 108 can achieve an efficient transverse current collection effect, and can transversely transmit current to the first electrode 105 and the second electrode 109, which is beneficial to reducing the series resistance of current collection, thereby being beneficial to improving the photoelectric conversion efficiency of the back contact battery 10. The first transparent conductive layer 104 and the second transparent conductive layer 108 also respectively play a certain role in blocking metal elements in the first electrode 105 and the second electrode 109, so that the risk that the metal elements in the first electrode 105 and the second electrode 109 diffuse towards the direction of the substrate 101 to damage the structure of the substrate 101 is reduced, and meanwhile, a certain role in antireflection is realized. The material of the transparent conductive oxide layer includes one or more of Indium Tin Oxide (ITO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), tin oxide (SnOx), aluminum doped zinc oxide (AZO). One of the first electrode 105 and the second electrode 109 is a positive electrode, and the other is a negative electrode.

It should be noted that, in the actual manufacturing process of the back contact cell 10, the doping element in the P-type doped amorphous silicon layer 107 may diffuse into the intrinsic amorphous silicon layer 106, and thus, the intrinsic amorphous silicon layer 106 in this embodiment is not a strictly zero doped "intrinsic amorphous silicon layer".

As shown in fig. 9, the back contact cell 10 further includes a passivation layer 1011 and an antireflection layer 1010, the passivation layer 1011 is disposed on the first surface 101a, and the antireflection layer 1010 is disposed on a side of the passivation layer 1011 facing away from the substrate 101 along the height direction Z of the back contact cell 10. The passivation layer 1011 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, titanium oxide, and aluminum oxide. The anti-reflection layer 1010 may include at least one of silicon nitride, silicon oxynitride, and silicon oxide. The passivation layer 1011 and the anti-reflection layer 1010 are arranged to be beneficial to enhancing the carrier concentration of the surface of the back contact battery 10 and improving the short circuit current and open circuit voltage of the back contact battery 10, thereby improving the battery efficiency.

In the structure of the back contact battery 10, the first surface 101a and the second surface 101b and the second region 101bb may have a textured structure, which is beneficial to improving the light absorptivity of the substrate 101, so as to improve the photoelectric conversion efficiency of the back contact battery 10.

The preparation method of the back contact battery 10 is as follows:

Step 1, providing a silicon wafer, and cleaning and polishing the silicon wafer to obtain a substrate 101.

The steps are used for removing the mechanical damage layer, organic matters and metal impurities on the surface of the silicon wafer, obtaining a clean and flat initial surface, improving the smoothness and cleanliness of the silicon wafer, reducing the surface defects of the silicon wafer and preparing for subsequent high-quality film deposition.

Step 2, sequentially forming a tunneling oxide layer 102 and an intrinsic polysilicon layer on the second surface 101b of the substrate 101.

In the above steps, the tunnel oxide layer is a SiOx layer. The tunnel oxide layer and the intrinsic polysilicon layer may be formed using one or more processes such as low pressure chemical vapor deposition, plasma chemical vapor deposition, physical chemical vapor deposition, or plasma enhanced atomic layer deposition.

And 3, performing phosphorus diffusion treatment on the intrinsic polycrystalline silicon layer by a high-temperature diffusion mode to form an N-type doped polycrystalline silicon layer 103, and generating a phosphorus-containing oxide layer, such as phosphosilicate glass (PSG).

And 4, forming a mask layer on the surface of the PSG.

In the above steps, the mask layer may be a SiNx mask or a SiOx mask.

And 5, the mask layer, the PSG and the N-type doped polycrystalline silicon layer 103 on the second region 101bb of the second surface 101 b.

In the above steps, the mask layer may be removed by a laser process, the PSG may be removed by an HF solution, and the N-type doped polysilicon layer 103 may be removed by a KOH solution or a TMAH solution.

Step 6. PSG on the first surface 101a of the substrate 101 is removed using an HF solution.

The PSG involved in the above steps is a by-product formed during step 3, and if not removed, the PSG will affect the subsequent texturing effect.

Step 7, performing texturing treatment on the second areas 101bb of the first surface 101a and the second surface 101b of the substrate 101 to form pyramid-shaped textured structures.

In the above step, the texturing process may be performed by a wet etching process, and in the above process, the tunnel oxide layer 102 on the second region 101bb is removed by the texturing solution.

Step 8, removing the mask layer and the PSG on the first region 101ba of the second surface 101b, and then cleaning and drying the substrate 101.

Step 9, preparing a passivation layer 1011 on the first surface 101 a.

In the above steps, the passivation layer 1011 may be formed by one or more processes such as low pressure chemical vapor deposition, plasma chemical vapor deposition, or atomic layer deposition.

Step 10, an anti-reflective layer 1010 is prepared over the passivation layer 1011.

In the above steps, the anti-reflection layer 1010 may be formed by one or more processes such as low pressure chemical vapor deposition, plasma chemical vapor deposition, or atomic layer deposition.

And 11, removing films such as amorphous silicon which are wound and plated on the back surface of the substrate 101 in the processes of the step 9 and the step 10 by using a chain etching device, and ensuring the cleanliness of the back surface structure.

Step 12, cleaning the substrate 101 to remove pollutants and natural oxide layers.

Step 13, depositing an intrinsic amorphous silicon layer 106 on the second region 101bb of the second surface 101 b.

The above steps are accomplished by means of low temperature deposition (less than 250 ℃).

Step 14, depositing a P-type doped amorphous silicon layer 107 in the second region 101bb of the second surface 101 b.

The above steps are performed by low temperature deposition (less than 250 ℃), and steps 13 and 14 are used to form a heterojunction contact structure in the second region 101 bb.

Step 15-depositing a TCO layer on the back light side of the substrate 101.

In step 16, a physical isolation structure is disposed between the first region 101ba and the second region 101bb to form the TCO layer into a first transparent conductive layer 104 and a second transparent conductive layer 108 that are independent of each other.

In the above step, the TCO layer between the first region 101ba and the second region 101bb may be specifically removed by laser patterning. Alternatively, acid resistant ink may be printed on the first and second regions 101ba and 101bb, respectively, and then the TCO layer between the first and second regions 101ba and 101bb, without printed ink, may be removed by means of acid washing.

Step 17, printing a first electrode 105 on the first transparent conductive layer 104 and a second electrode 109 on the second transparent conductive layer 108.

In the above steps, the first electrode 105 and the second electrode 109 may be printed in a screen printing manner. Specifically, the first electrode 105 and the second electrode 109 should be printed first with the fine grid 2, then with the insulator 3 laid on, and finally with the main grid 4.

The substrate 101 is annealed and light-injected to obtain the back contact cell 10, step 18.

In the above steps, the annealing treatment is beneficial to forming good ohmic contact between the first electrode 105 and the N-type doped polysilicon layer 103, between the second electrode 109 and the P-type doped amorphous silicon layer 107, and also can repair some damages inside the substrate 101 and improve the electrical properties of the TCO layer. The photo-injection process can passivate defects inside and at the interface of the substrate 101 with photo-generated carriers, which is advantageous in improving the open circuit voltage and conversion efficiency of the back contact cell 10.

The application also provides a back contact laminated cell 20, as shown in fig. 10, the back contact laminated cell 20 comprises a back contact bottom cell 201 and a perovskite top cell 202, and the perovskite top cell 202 is electrically connected with the light-facing surface of the back contact bottom cell 201. The back contact bottom cell 201 may be the back contact cell 10 with a main grid or the back contact cell 10 without a main grid as described above. The perovskite top cell 202 is a thin film solar cell with perovskite material as the photoactive layer. The structure of the perovskite top cell 202 mainly comprises a transparent conductive substrate, an electron transport layer, a perovskite light absorption layer, a hole transport layer and a metal electrode, wherein the components cooperate together, so that the perovskite top cell 202 can effectively absorb sunlight and convert the sunlight into electric energy, and a perovskite material in the perovskite light absorption layer has excellent light absorption performance, can absorb a wider spectral range and effectively convert a short wavelength spectrum, so that the perovskite top cell 202 has high photoelectric conversion efficiency.

The embodiment of the application also provides a photovoltaic module, as shown in fig. 11 and 12, which includes a plurality of photovoltaic cells and solder strips 30, wherein the photovoltaic cells are the back contact cells 10 described above, or the photovoltaic cells are the back contact laminated cells 20 described above. The main grids 4 of two adjacent photovoltaic cells along the second direction Y are electrically connected by a solder strip 30.

The photovoltaic module further includes a front plate 40, a front encapsulation layer 50, a back encapsulation layer 60, and a back plate 70, where the front plate 40 and the back plate 70 jointly clamp the front encapsulation layer 50, the photovoltaic cell, the solder strip 30, and the back encapsulation layer 60, and form the photovoltaic module through lamination encapsulation. The front packaging layer 50 is used for protecting the light facing surface of the photovoltaic cell, the back packaging layer 60 is used for protecting the backlight surface of the photovoltaic cell, meanwhile, in the lamination process of the photovoltaic module, the front packaging layer 50 and the back packaging layer 60 are used for packaging and protecting the photovoltaic cell and the solder strip 30, so that the influence of the external environment on the performances of the photovoltaic cell and the solder strip 30 is prevented, and meanwhile, the front plate 40, the back plate 70, the photovoltaic cell and the solder strip 30 can be bonded into a whole.

The material of the front and back plates 40 and 70 may be one of rigid materials such as tempered glass, polyethylene TEREPHTHALATE PET, and Polycarbonate (PC), or one of flexible materials such as polyvinyl fluoride (Polyvinyl Fluoride PVF), ethylene-tetrafluoroethylene copolymer (Ethylene-Tetra-Fluoro-ETHYLENE ETFE), and vinylidene fluoride (Polyvinylidene Fluoride PVDF). The front packaging layer 50 and the back packaging layer 60 are adhesive films, the adhesive film can be one of ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer (POE), polyvinyl butyral (PVB) and other materials, and the front packaging layer 50 and the back packaging layer 60 can also be EPE adhesive films (EVA-POE-EVA co-extrusion structure) or EP adhesive films (EVA-POE co-extrusion structure).

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that it comprises:

The back surface of the body (1) is provided with a fine grid (2), a main grid (4) and an insulating component (3).

The fine grid (2) extends along a first direction, and the fine grid (2) includes a first fine grid (21) and a second fine grid (22) that are alternately distributed in a second direction, and the insulating member (3) covers a portion of the second fine grid (22);

The main grid (4) extends along the second direction and includes a main body portion (41) and a connecting portion (42) alternately distributed in the second direction. The main body portion (41) is located above the insulating member (3), and the connecting portion (42) is electrically connected to the first fine grid (21).

In the first direction, the width of the connecting portion (42) is greater than the width of the main body portion (41);

The connecting part (42) includes a connecting body (421) and a protruding structure (422), the protruding structure (422) being located at at least one end of the connecting body (421) along the first direction;

The first direction intersects with the second direction.

2. The back contact battery according to claim 1, wherein the protruding structure (422) is provided with a notch (422a) that is recessed inward along the first direction.

3. The back contact battery according to claim 2, wherein at least a portion of the first fine grid (21) is located within the notch (422a).

4. The back contact battery according to claim 2, wherein the protrusion structure (422) includes at least two protrusions (422b) arranged along the second direction, and the notch (422a) is formed between two adjacent protrusions (422b).

5. The back contact battery according to claim 4, characterized in that the protrusion structure (422) includes two protrusions (422b), and along the second direction, the two protrusions (422b) are respectively located on both sides of the first fine grid (21);

The two protrusions (422b) are of equal length in the second direction.

6. The back contact battery according to claim 1, characterized in that, along the first direction, the width W1 of the connecting body (421) and the width W2 of the connecting part (42) satisfy: 1.1:1≤W2:W1≤2:1.

7. The back contact battery according to claim 1, wherein the connecting body (421) is provided with the protruding structure (422) on both sides along the first direction.

The two protrusions (422) have the same width in the first direction.

8. The back contact battery according to claim 1, characterized in that, along the first direction, the width W2 of the connecting portion (42) and the width W3 of the insulating member (3) satisfy: 1:5≤W2:W3≤3:7.

9. The back contact battery according to claim 1, characterized in that, along the second direction, the width D1 of the second fine grid (22) and the length L1 of the insulating member (3) are: D1:L1≥1:10.

10. The back contact battery according to any one of claims 1-9, characterized in that the main grid (4) comprises a first segment (4a), a second segment (4b) and a third segment (4c), and along the second direction, the second segment (4b) and the third segment (4c) are electrically connected to the two ends of the first segment (4a) respectively;

At least one of the second segment (4b) and the third segment (4c) is a harpoon structure.

11. The back contact battery according to claim 10, wherein the first segment (4a), the second segment (4b) and the third segment (4c) are each provided with the main body (41) and the connecting portion (42).

12. A back-contact stacked battery, characterized in that it comprises a back-contact bottom battery (201) and a perovskite top battery (202), wherein the perovskite top battery (202) is electrically connected to the light-facing surface of the back-contact bottom battery (201), and the back-contact bottom battery (201) is the back-contact battery (10) according to any one of claims 1-11.

13. A photovoltaic module, characterized in that it comprises:

Multiple photovoltaic cells, wherein the photovoltaic cells are back-contact cells (10) as described in any one of claims 1-11, or the photovoltaic cells are back-contact tandem cells (20) as described in claim 12.

The welding strip (30) electrically connects two adjacent photovoltaic cells along the second direction.