Battery piece, battery string and photovoltaic module

Abstract

The utility model relates to a battery piece, a battery string and a photovoltaic module, and belongs to the technical field of solar cells. The battery piece comprises a battery body and a metal foil, and the backlight surface of the battery body is provided with a back surface grid line; the metal foil is connected to the back surface grid line; a layer of metal foil is arranged on the backlight side of the cell body to connect the grid lines, so that lower line loss can be realized under the condition that an aluminum back surface field is thinner, even no aluminum back surface field exists or a small amount of silver paste is used, further, less cutting in the preparation process can be realized, the loss of a cell piece is favorably reduced, and meanwhile, warping or cost increase is not caused.

Description

TECHNICAL FIELD

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

[0002] At present, the line loss of the cell piece of the shingled cell is high, and the cell piece needs to be cut into a smaller size to control the line loss, but multiple cutting will cause damage to the cell piece and affect the photoelectric conversion efficiency. In order to improve this problem, it is usually to increase the wet weight of the aluminum back field (PERC cell) or increase the amount of silver paste (TOPCon cell), but this brings new problems, for example, the increase of the wet weight of the aluminum back field will increase the probability of the warping of the cell piece, and further reduce the yield rate of the cell piece or the adaptability to the production equipment; or the increase of the amount of silver paste will increase the cost of the cell piece. SUMMARY

[0003] The purpose of the present application is to provide a cell piece, a cell string and a photovoltaic module, which can realize less cutting while reducing line loss, and also consider low warping and low cost of the cell piece.

[0004] In the first aspect, the embodiments of the present application provide a cell piece, which comprises:

[0005] a cell body, a back surface of the cell body being provided with a back surface grid line;

[0006] and a metal foil connected to the back surface grid line.

[0007] In the above implementation process, by arranging a layer of metal foil to connect the grid line on the back light side of the cell body, the line loss can be reduced under the condition of thin aluminum back field, even without aluminum back field or less silver paste, and then less cutting in the preparation process can be realized, which is beneficial to reduce the loss of the cell piece, and at the same time does not cause the increase of warping or cost.

[0008] As an optional implementation manner, the thickness of the metal foil is 10-30 microns.

[0009] In the above implementation process, the thicker the thickness of the metal foil is, the more conducive to the reduction of the line loss of the cell piece, and the thinner the thickness of the metal foil is, the more conducive to the control of the cost of the cell piece. By controlling the thickness of the metal foil to be 10-30 microns, the line loss and the manufacturing cost of the cell piece are considered.

[0010] As an optional implementation manner, the area of the metal foil is not greater than the area of the cell body, and the minimum distance between the edge of the metal foil and the edge of the cell body is 0-10 mm.

[0011] In the above implementation process, the larger the area of the metal foil, the more conducive to the reduction of the battery piece line loss, the smaller the area of the metal foil, the more conducive to the control of the battery piece cost, by controlling the minimum distance between the edge of the metal foil and the edge of the battery body to be 0-10mm, the battery piece line loss and the manufacturing cost are realized.

[0012] As an optional implementation, the length of the battery body is 182mm-210mm; and / or

[0013] The width of the battery body is 30mm-105mm.

[0014] In the above implementation process, since the metal foil is provided, under the same line loss, the size of the single battery can be larger, the slicing frequency is reduced, and the slicing loss of the battery piece is reduced. By controlling the length of the battery body to be 182mm-210mm and the width to be 30mm-105mm, the line loss and the photoelectric conversion efficiency of the battery piece are considered.

[0015] As an optional implementation, the back surface grid line includes a main grid line and a secondary grid line; the thickness of the main grid line is 3-5μm, the width of the main grid line is 20-40μm, and the interval of the main grid line is 5-15mm; the thickness of the secondary grid line is 5-10μm, the width of the secondary grid line is 10-30μm, and the interval of the secondary grid line is 1-2mm.

[0016] In the above implementation process, since the metal foil is provided, under the same line loss, the material of the grid line can be reduced, and correspondingly, the width and thickness of the grid line of the battery piece can be reduced, and the interval can be increased. By controlling the thickness of the main grid line to be 3-5μm, the width to be 20-40μm, and the interval to be 5-15mm; the thickness of the secondary grid line to be 5-10μm, the width to be 10-30μm, and the interval to be 1-2mm, the line loss and the manufacturing cost of the battery piece are considered.

[0017] As an optional implementation, the back surface grid line includes a main grid line; the thickness of the main grid line is 3-5μm, the width of the main grid line is 20-40μm, and the interval of the main grid line is 1-2mm.

[0018] In the above implementation process, since the metal foil is provided, under the same line loss, the material of the grid line can be reduced, and correspondingly, the width and thickness of the grid line of the battery piece can be reduced, and the interval can be increased. By controlling the thickness of the main grid line to be 3-5μm, the width to be 20-40μm, and the interval to be 1-2mm, the line loss and the manufacturing cost of the battery piece are considered.

[0019] As an optional implementation, the metal foil and the back surface grid line are connected through a conductive connection layer.

[0020] As an optional implementation, the material of the conductive connection layer is silver paste dispensing, printed tin paste or conductive glue.

[0021] As an optional implementation, the connection position of the metal foil and the battery body includes a PAD point of the battery body.

[0022] In the above implementation process, the connection of the metal foil and the battery body at the PAD point is conducive to the connection reliability and conductivity of the two.

[0023] In a second aspect, the embodiments of the present application provide a battery string, which comprises:

[0024] at least two battery pieces provided by the first aspect;

[0025] a solder strip connected to the main surface grid line on the light-receiving surface of the battery piece;

[0026] and a connection part, one end of which is connected to the metal foil of one of the two adjacent battery pieces, and the other end of which is connected to the solder strip arranged on the light-receiving surface of the other of the two adjacent battery pieces.

[0027] In the above implementation process, by arranging a layer of metal foil on the back light side of the battery piece to replace the solder strip to connect the grid line, lower line loss can be achieved in the case of thinner aluminum back field, even without aluminum back field or less silver paste material, thereby realizing less cutting in the preparation process, which is conducive to reducing the loss of the battery piece, and does not cause warping or cost increase.

[0028] As an optional implementation, the connection part is a connection solder strip, and the connection solder strip and the solder strip are integrally formed.

[0029] As an optional implementation, the connection solder strip has a flat part, the flat part is connected to the metal foil, and the thickness of the flat part is not more than 100 μm.

[0030] In the above implementation process, the thickness of the flat part is controlled, which is conducive to controlling the thickness of the back side glue layer and facilitating the welding of the battery piece, thereby reducing the hidden cracks of the battery piece.

[0031] As an optional implementation, the connection part is a connection metal foil, and the connection metal foil and the metal foil are integrally formed.

[0032] As an optional implementation, the overlapping area of the connection metal foil and the light-receiving surface of the battery body has a width of not more than 1 mm.

[0033] In the above implementation process, by controlling the width of the overlapping area, the influence on the light-receiving area of the light-receiving surface can be reduced, and the photoelectric conversion efficiency is beneficial.

[0034] In a third aspect, the embodiments of the present application provide a photovoltaic module, which comprises the cell string provided in the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0036] Figure 1 A structure schematic diagram of the back light side of the cell piece provided in the embodiments of the present application;

[0037] Figure 2 A structure schematic diagram of the back surface grid line provided in the embodiments of the present application Figure One ;

[0038] Figure 3 A local enlarged schematic diagram of A in the middle Figure 2

[0039] Figure 4 A structure schematic diagram of the back surface grid line provided in the embodiments of the present application Figure Two ;

[0040] Figure 5 A structure schematic diagram of the shingle photovoltaic module provided in the embodiments of the present application Figure One ;

[0041] Figure 6 A structure schematic diagram of the shingle photovoltaic module provided in the embodiments of the present application Figure Two .

[0042] Reference signs: 1000-cell string; 1100-cell piece; 1110-cell body; 1111-main surface grid line; 1112-back surface grid line; 1112a-main grid line; 1112b-secondary grid line; 1113-PAD point; 1120-metal foil; 1200-solder strip; 1300-connection part; 1310-flat part. DETAILED DESCRIPTION

[0043] ​In order to make the objects, 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. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0044] In the description of the present application, it should be noted that the positions or location relationships indicated by the terms "in", "out" and the like are based on the positions or location relationships shown in the drawings, or the positions or location relationships commonly placed when the products of the present application are used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated devices or elements must have a particular position, be constructed and operated in a particular position, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" and the like are only used for differentiation in description and cannot be understood as indicating or implying relative importance.

[0045] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "set", "connected" should be understood broadly, for example, can be fixedly connected, can be detachably connected, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium, can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] At present, the line loss of the cell sheet 1100 of the shingled battery is high, and the cell sheet 1100 needs to be cut into smaller size to control the line loss, but multiple cutting will cause damage to the cell sheet 1100 and affect the photoelectric conversion efficiency. In order to improve this problem, it is usually to increase the wet weight of aluminum back field (PERC battery) or increase the amount of silver paste (TOPCon battery), but this brings new problems, for example, the increase of the wet weight of aluminum back field will increase the probability of warping of the cell sheet 1100, and further reduce the yield rate of the cell sheet 1100 or reduce the adaptability to the production equipment; or the increase of the amount of silver paste will increase the cost of the cell sheet 1100.

[0047] Therefore, the present application intends to provide a cell sheet 1100, by setting a metal foil 1120 on the back light surface of the cell body 1110, which can reduce the line loss and realize less cutting, while considering the low warping and low cost of the cell sheet 1100.

[0048] Figure 1 The structural schematic diagram of the back light side of the cell sheet 1100 provided by the embodiments of the present application is as follows, Figure 1As shown, the battery piece 1100 provided by the embodiments of the present application includes a battery body 1110 and a metal foil 1120, the back surface of the battery body 1110 is provided with a back surface grid line 1112, and the metal foil 1120 is connected to the back surface grid line 1112.

[0049] The battery piece 1100 can realize lower line loss in the case of thinner aluminum back field, even without aluminum back field or less silver paste material, and then can realize less cutting in the preparation process, which is beneficial to reduce the loss of the battery piece 1100, and does not cause warping or cost increase.

[0050] It should be noted that the connection between the metal foil 1120 and the battery body 1110 can be realized by silver paste dispensing, tin paste printing or conductive adhesive, and the solidification can be realized by a solidification furnace (a long-distance heating channel with platform adsorption, hot air circulation and temperature rising, holding and cooling functions) to form a conductive connection layer after solidification. The conductive connection layer is arranged on the battery body 1110 in a distributed dotting manner. For example, the tin paste can be a traditional soldering tin paste with a metal content of 85% to 90%, an alloy cost of Sn63Pb37 or Sn60Pb40, and a soldering paste content of 10% to 15%; the conductive adhesive can be a glue with adhesive material, UV glue, heat-curing glue or conductive adhesive; the tin paste and the conductive adhesive mainly have adhesive function to bond the silver paste dots and the copper foil / aluminum foil of the battery piece 1100, and additional conductive function. It can be understood that in other embodiments, those skilled in the art can also use other materials to form the conductive connection layer.

[0051] In some embodiments, the connection position of the metal foil 1120 and the battery body 1110 includes a PAD point 1113 of the battery body 1110. It can be understood that the conductive connection layer can be arranged at the PAD point 1113 position on the battery body 1110 to realize the connection between the metal foil 1120 and the battery body 1110. By realizing the connection between the metal foil 1120 and the battery body 1110 at the PAD point 1113, the connection reliability and conductivity of the two can be improved. Of course, those skilled in the art can understand that in addition to realizing the connection between the metal foil 1120 and the battery body 1110 at the PAD point 1113, the connection can also be realized at other positions of the back surface grid line 1112.

[0052] Generally, the battery piece 1100 is also provided with a cover glass on both sides, and a glue film is filled between the cover glass and the battery body 1110 to realize the protection of the battery body 1110, and the solder strip 1200 and the metal foil 1120 are embedded in the glue film.

[0053] Since the solder strip 1200 on the backlight side is replaced by the metal foil 1120, and the thickness of the metal foil 1120 is much smaller than that of the solder strip 1200, the thickness of the adhesive film can be reduced, which is further conducive to the cost control of the battery piece 1100.

[0054] In some embodiments, the metal foil 1120 can be selected from an aluminum foil or a copper foil.

[0055] The thicker the thickness of the metal foil 1120, the more conducive to the reduction of the line loss of the battery piece 1100, and the thinner the thickness of the metal foil 1120, the more conducive to the cost control of the battery piece 1100. In some embodiments, the thickness of the metal foil 1120 is 10 μm to 30 μm. By controlling the thickness of the metal foil 1120 to be 10 μm to 30 μm, the line loss and the manufacturing cost of the battery piece 1100 are considered.

[0056] For example, the thickness of the metal foil 1120 can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, or 30 μm, etc., which can also be any value in the range of 10 μm to 30 μm.

[0057] The larger the area of the metal foil 1120, the more conducive to the reduction of the line loss of the battery piece 1100, and the smaller the area of the metal foil 1120, the more conducive to the cost control of the battery piece 1100. In some embodiments, the area of the metal foil 1120 is not greater than the area of the battery body 1110, and the minimum distance between the edge of the metal foil 1120 and the edge of the battery body 1110 is 0 to 10 mm. The minimum distance between the edge of the metal foil 1120 and the edge of the battery body 1110 refers to the distance between the edge of the metal foil 1120 and the edge of the corresponding battery monomer. By controlling the minimum distance between the edge of the metal foil 1120 and the edge of the battery body 1110 to be 0 to 10 mm, the line loss and the manufacturing cost of the battery piece 1100 are considered.

[0058] For example, the minimum distance between the edge of the metal foil 1120 and the edge of the battery body 1110 can be 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, or 10 mm, etc., which can also be any value in the range of 0 to 10 mm.

[0059] Due to the metal foil 1120, the size of the monolithic cell can be larger, the slicing frequency can be reduced (to less than 3 times), and the slicing loss of the cell 1100 can be reduced under the same line loss. Generally, the size of the uncut cell 1100 is 210*210, 182*182, 210*182, etc. Therefore, in some embodiments, the length of the cell body 1110 is 182mm-210mm; and the width of the cell body 1110 is 30mm-105mm. By controlling the length of the cell body 1110 to be 182mm-210mm and the width to be 30mm-105mm, the line loss and the photoelectric conversion efficiency of the cell 1100 can be considered.

[0060] Due to the metal foil 1120, the material of the grid line can be reduced under the same line loss, and the width and thickness of the grid line of the cell 1100 can be reduced and the spacing can be increased.

[0061] Figure 2 And Figure 3 The structure diagram of the back surface grid line 1112 provided by the embodiments of the present application is shown in FIG. 1B. Figure 2 And Figure 3 As shown in FIG. 1B, in some embodiments, the back surface grid line 1112 can be provided as a main grid line 1112a and a sub grid line 1112b. At this time, the current transmission of the cell 1100 has two paths, one of which is through the sub grid line 1112b to the main grid line 1112a, and then transmitted by the main grid line 1112a and the metal foil 1120; the other path is through the sub grid line 1112b to directly contact the metal foil 1120 for transmission. Further, the thickness of the main grid line 1112a is 3μm-5μm, the width of the main grid line 1112a is 20μm-40μm, and the spacing of the main grid line 1112a is 5mm-15mm; the thickness of the sub grid line 1112b is 5μm-10μm, the width of the sub grid line 1112b is 10μm-30μm, and the spacing of the sub grid line 1112b is 1mm-2mm. By controlling the thickness of the main grid line 1112a to be 3μm-5μm, the width to be 20μm-40μm, and the spacing to be 5mm-15mm; the thickness of the sub grid line 1112b to be 5μm-10μm, the width to be 10μm-30μm, and the spacing to be 1mm-2mm, the line loss and the manufacturing cost of the cell 1100 can be considered.

[0062] For example, the thickness of the main grid line 1112a can be 3 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, or 5 μm, etc., which can also be any value in the range of 3 μm to 5 μm. The width of the main grid line 1112a can be 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, or 40 μm, etc., which can also be any value in the range of 20 μm to 40 μm. The interval of the main grid line 1112a can be 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm, etc., which can also be any value in the range of 5 mm to 15 mm. The thickness of the sub grid line 1112b can be 5 μm, 5.2 μm, 5.4 μm, 5.6 μm, 5.8 μm, 6 μm, 6.2 μm, 6.4 μm, 6.6 μm, 6.8 μm, 7 μm, 7.2 μm, 7.4 μm, 7.6 μm, 7.8 μm, 8 μm, 8.2 μm, 8.4 μm, 8.6 μm, 8.8 μm, 9 μm, 9.2 μm, 9.4 μm, 9.6 μm, 9.8 μm, or 10 μm, etc., which can also be any value in the range of 5 μm to 10 μm. The width of the sub grid line 1112b can be 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm, etc., which can also be any value in the range of 10 μm to 30 μm. The interval of the sub grid line 1112b can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm, etc., which can also be any value in the range of 1 mm to 2 mm.

[0063] Figure 4 The structure diagram of the back grid line 1112 provided by the embodiment of the present application is shown in FIG. 11B. Figure 4As shown, in some embodiments, the back surface grid lines 1112 can be provided as the main grid lines 1112a only. At this time, the current transmission path of the battery piece 1100 is the transmission by the main grid lines 1112a and the transmission by the metal foils 1120. Further, the thickness of the main grid lines 1112a is 3-5 μm, the width of the main grid lines 1112a is 20-40 μm, and the interval of the main grid lines 1112a is 1-2 μm. By controlling the thickness of the main grid lines 1112a to be 3-5 μm, the width of the main grid lines 1112a to be 20-40 μm, and the interval of the main grid lines 1112a to be 1-2 μm, the line loss and the manufacturing cost of the battery piece 1100 can be considered.

[0064] For example, the thickness of the main grid lines 1112a can be 3 μm, 3.2 μm, 3.4 μm, 3.6 μm, 3.8 μm, 4 μm, 4.2 μm, 4.4 μm, 4.6 μm, 4.8 μm, or 5 μm, etc., which can also be any value in the range of 3-5 μm. The width of the main grid lines 1112a can be 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, 30 μm, 31 μm, 32 μm, 33 μm, 34 μm, 35 μm, 36 μm, 37 μm, 38 μm, 39 μm, or 40 μm, etc., which can also be any value in the range of 20-40 μm. The interval of the main grid lines 1112a can be 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2 mm, etc., which can also be any value in the range of 1-2 mm.

[0065] Figure 5 And Figure 6 The structural schematic diagram of the battery string 1000 provided by the embodiments of the present application is as shown in Figure 5 And Figure 6 As shown, based on the same aspect, the embodiments of the present application provide a battery string 1000, which comprises a plurality of battery pieces 1100 as provided above, a solder strip 1200, and a connecting part 1300. The battery body 1110 comprises a silicon wafer substrate, main surface grid lines 1111 provided on the light-receiving surface of the silicon wafer substrate, and back surface grid lines 1112 provided on the light-reflecting surface of the silicon wafer substrate. The solder strip 1200 is connected with the main surface grid lines 1111, and the metal foil 1120 is connected with the back surface grid lines 1112. The plurality of battery pieces 1100 are distributed in a shingle manner, and two adjacent battery pieces 1100 are connected through the connecting part 1300. One end of the connecting part 1300 is connected with the solder strip 1200 of one battery piece 1100, and the other end of the connecting part 1300 is connected with the metal foil 1120 of another battery piece 1100.

[0066] The battery string 1000 is implemented based on the above-mentioned battery piece 1100, and the specific content of the battery piece 1100 can refer to the above-mentioned embodiments. Since the battery string 1000 adopts part or all of the technical solutions of the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, and will not be described one by one here.

[0067] The battery string 1000 replaces the solder strip 1200 to connect the back surface grid line 1112 by arranging a layer of metal foil 1120 on the back light surface of the battery piece 1100. In the case of thinner aluminum back field, even without aluminum back field or less silver paste material, lower line loss can be achieved, and then less cutting in the preparation process can be achieved, which is beneficial to reduce the loss of the battery piece 1100, and at the same time does not cause warping or cost increase.

[0068] Please refer to Figure 5 In some embodiments, the connecting part 1300 can be formed by extending the solder strip 1200, that is, the connecting part 1300 is a connecting solder strip, and the connecting solder strip and the solder strip 1200 are integrally formed.

[0069] Further, the connecting solder strip has a flat part 1310, the flat part 1310 is connected with the metal foil 1120, and the thickness of the flat part 1310 is not greater than 100 μm. Controlling the thickness of the flat part 1310 is beneficial to control the thickness of the back side adhesive layer, and is also beneficial to the welding of the battery piece 1100, and further reduces the hidden cracks of the battery piece 1100. It can be understood that the smaller the thickness of the flat part 1310 is, the better. However, at present, it is limited by the preparation process, and the limit thickness of the flat part 1310 on the solder strip 1200 is about 20 μm, so the thickness of the flat part 1310 is in the range of 20 μm to 100 μm, which is the currently achievable preferred range. When the preparation process is further optimized, the flat part 1310 can be further thinned.

[0070] For example, the thickness of the flat part 1310 can be 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, etc., which can also be any value in the range of not greater than 100 μm.

[0071] Please refer to Figure 6 In some embodiments, the connecting part 1300 can be formed by extending the metal foil 1120, that is, the connecting part 1300 is a connecting metal foil, and the connecting metal foil and the metal foil 1120 are integrally formed.

[0072] Further, the width of the overlapping area between the connecting metal foil and the light-receiving surface of the battery body 1110 is not more than 1 mm. The width of the overlapping area refers to the length in the connecting direction of the battery piece 1100. By controlling the width of the overlapping area, the influence on the light-receiving area of the light-receiving surface can be reduced, which is beneficial to the photoelectric conversion efficiency.

[0073] For example, the width of the overlapping area between the connecting metal foil and the light-receiving surface of the battery body 1110 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, etc., which can also be any value within the range of not more than 1 mm.

[0074] Based on the same aspect, the embodiment of the present application provides a photovoltaic module, which comprises the battery string 1000 provided above.

[0075] The photovoltaic module is realized based on the battery string 1000 described above, and the specific content of the battery string 1000 can refer to the above embodiments. Since the photovoltaic module adopts part or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be repeated here.

[0076] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0077] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A battery sheet, characterized by, The battery piece comprises: a battery body, a back surface of the battery body being provided with a back surface grid line, the back surface grid line comprising a main grid line and a sub grid line; and a metal foil, the metal foil being connected to the back surface grid line.

2. The battery sheet of claim 1, wherein, The thickness of the metal foil is 10-30 μm.

3. The battery sheet of claim 1, wherein, The area of the metal foil is not greater than the back surface area of the battery body, and the minimum distance between the edge of the metal foil and the edge of the battery body is 0-10 mm.

4. The battery sheet of claim 1, wherein, The length of the battery body is 182-210 mm; and / or The width of the battery body is 30-105 mm.

5. The battery sheet of claim 1, wherein, The thickness of the main grid line is 3-5 μm, the width of the main grid line is 20-40 μm, and the interval of the main grid line is 5-15 mm; the thickness of the sub grid line is 5-10 μm, the width of the sub grid line is 10-30 μm, and the interval of the sub grid line is 1-2 mm.

6. The battery sheet of claim 1, wherein, The metal foil and the back surface grid line are connected through a conductive connecting layer; and / or The material of the conductive connecting layer is silver paste dispensing, printed tin paste or conductive adhesive.

7. The battery sheet of claim 1, wherein, The connecting position of the metal foil and the battery body comprises a PAD point of the battery body.

8. A battery string, characterized by The battery string comprises: at least two battery pieces according to any one of claims 1-7; a solder strip, the solder strip being connected to the main surface grid line of the light-receiving surface of the battery piece; and a connecting portion, one end of the connecting portion being connected to the metal foil of one of the two adjacent battery pieces, and the other end of the connecting portion being connected to the solder strip arranged on the light-receiving surface of the other of the two adjacent battery pieces.

9. The battery string of claim 8, wherein, The connecting portion is a connecting solder strip, and the connecting solder strip and the solder strip are integrally formed.

10. The battery string of claim 9, wherein, The connecting solder strip has a flat portion, the flat portion being connected to the metal foil, and the thickness of the flat portion is not greater than 100 μm.

11. The battery string of claim 8, wherein, The connecting portion is a connecting metal foil, and the connecting metal foil and the metal foil are integrally formed.

12. The battery string of claim 11, wherein, The overlapping area width of the connecting metal foil and the light-receiving surface of the battery body is not more than 1 mm.

13. A photovoltaic module, characterized by The photovoltaic module comprises the battery string according to any one of claims 8-12.

Images