Solar cell, cell string and photovoltaic module

Abstract

A solar cell, a cell string and a photovoltaic module, which belong to the technical field of solar cells. The solar cell comprises a cell body and a metal foil, wherein back surface grid lines are disposed on a non-illuminated surface of the cell body, and the metal foil is connected to the back surface grid lines. By means of disposing a layer of metal foil on a non-illuminated side of the cell body to connect to grid lines, relatively low line losses can be achieved when an aluminum back surface field is relatively thin or is even absent, or when a small amount of silver paste is used, thereby achieving fewer cuts during a preparation process, and reducing the loss of the solar cell without causing warping or an increase in costs.

Description

A battery piece, a battery string and a photovoltaic module

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese Invention Patent Application No. 2024215709541, filed on July 3, 2024, and entitled "A battery piece, a battery string and a photovoltaic module", the contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present application relates to the technical field of solar cells, in particular to a battery piece, a battery string and a photovoltaic module. BACKGROUND

[0004] At present, the line loss of the battery piece of the shingled battery is high, and the battery piece needs to be cut into a smaller size to control the line loss, but multiple cutting will cause damage to the battery 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 battery) or increase the amount of silver paste (TOPCon battery), 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 battery piece, and further reduce the yield rate of the battery piece or reduce the adaptability to the production equipment; or the increase of the amount of silver paste will increase the cost of the battery piece.

[0005] SUMMARY

[0006] The purpose of the present application is to provide a battery piece, a battery string and a photovoltaic module, which can reduce the line loss and realize less cutting while considering the low warping and low cost of the battery piece.

[0007] In a first aspect, the embodiments of the present application provide a battery piece, which comprises:

[0008] a battery body, a back surface of the battery body being provided with a back surface grid line;

[0009] and a metal foil connected to the back surface grid line.

[0010] In the above implementation process, by arranging a layer of metal foil to connect the grid line on the back light side of the battery body, the line loss can be reduced under the condition that the aluminum back field is thin, or even there is no aluminum back field, or the amount of silver paste is small, and then the cutting process can be realized. less, which is conducive to reducing the loss of the battery piece, and at the same time, it does not cause warping or cost increase.

[0011] As an optional implementation manner, the thickness of the metal foil is 10-30 microns.

[0012] In the above implementation process, the thicker the thickness of the metal foil, the more conducive to the reduction of the battery piece line loss, the thickness of the metal foil, the more conducive to the control of the battery piece cost, by controlling the thickness of the metal foil to 10 μm ~ 30 μm, the battery piece line loss and manufacturing cost are realized.

[0013] As an optional implementation, the area of the metal foil is not greater than the 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.

[0014] 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 0 ~ 10 mm, the battery piece line loss and manufacturing cost are realized.

[0015] As an optional implementation, the length of the battery body is 182 mm ~ 210 mm; and / or

[0016] The width of the battery body is 30 mm ~ 105 mm.

[0017] 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 182 mm ~ 210 mm and the width to be 30 mm ~ 105 mm, the line loss and photoelectric conversion efficiency of the battery piece are realized.

[0018] 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 μm ~ 5 μm, the width of the main grid line is 20 μm ~ 40 μm, and the interval of the main grid line is 5 mm ~ 15 mm; the thickness of the secondary grid line is 5 μm ~ 10 μm, the width of the secondary grid line is 10 μm ~ 30 μm, and the interval of the secondary grid line is 1 mm ~ 2 mm.

[0019] 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 μm ~ 5 μm, the width to be 20 μm ~ 40 μm, and the interval to be 5 mm ~ 15 mm; the thickness of the secondary grid line is 5 μm ~ 10 μm, the width is 10 μm ~ 30 μm, and the interval is 1 mm ~ 2 mm, the line loss and manufacturing cost of the battery piece are realized.

[0020] As an optional implementation, the back surface grid line comprises a main grid line; 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 1-2 mm.

[0021] In the above implementation, due to the metal foil, 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, the interval can be increased, and the sub-grid line can not be arranged. By controlling the thickness of the main grid line to be 3-5 μm, the width of the main grid line to be 20-40 μm, and the interval of the main grid line to be 1-2 mm, the line loss and manufacturing cost of the battery piece can be considered.

[0022] As an optional implementation, the metal foil and the back surface grid line are connected through a conductive connection layer.

[0023] As an optional implementation, the material of the conductive connection layer is silver paste dispensing, printed tin paste, or conductive glue.

[0024] As an optional implementation, the connection position of the metal foil and the battery body comprises a PAD point of the battery body.

[0025] In the above implementation, the connection of the metal foil and the battery body is realized at the PAD point, which is beneficial to the connection reliability and conductivity of the two.

[0026] In a second aspect, the embodiments of the present application provide a battery string, which comprises:

[0027] at least two battery pieces provided in the first aspect;

[0028] a solder strip connected to the main surface grid line of the light-receiving surface of the battery piece;

[0029] and a connection part, one end of the connection part being connected to the metal foil of one of the two adjacent battery pieces, and the other end of the connection part being connected to the solder strip arranged on the light-receiving surface of the other of the two adjacent battery pieces.

[0030] In the above implementation, 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, under the condition that the aluminum back field is thin, even without aluminum back field or the silver paste material is less, a lower line loss can be realized, and then the cutting process can be reduced, which is beneficial to reducing the loss of the battery piece, and does not cause warping or cost increase.

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

[0032] As an optional implementation, the connecting ribbon has a flat part, the flat part is connected with the metal foil, and the thickness of the flat part is not greater than 100 μm.

[0033] In the above implementation, the thickness of the flat part is controlled, which is beneficial to control the thickness of the back side adhesive layer and the welding with the battery piece, and further reduces the hidden crack of the battery piece.

[0034] As an optional implementation, the connecting part is a connecting metal foil, and the connecting metal foil and the metal foil are integrally formed.

[0035] As an optional implementation, the width of the overlapping area of the connecting metal foil and the light-receiving surface of the battery body is not greater than 1 mm.

[0036] In the above implementation, 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.

[0037] In a third aspect, the embodiments of the present application provide a photovoltaic module, which comprises the battery string provided in the second aspect. BRIEF DESCRIPTION OF DRAWINGS

[0038] 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.

[0039] Fig. 1 is a structural schematic diagram of the back light side of the battery piece provided by the embodiments of the present application;

[0040] Fig. 2 is a structural schematic diagram of the back surface grid line provided by the embodiments of the present application;

[0041] Fig. 3 is a partial enlarged schematic diagram of A in Fig. 2;

[0042] Fig. 4 is a structural schematic diagram of the back surface grid line provided by the embodiments of the present application;

[0043] Fig. 5 is a structural schematic diagram of the shingled photovoltaic module provided by the embodiments of the present application;

[0044] Fig. 6 is a structural schematic diagram of the shingled photovoltaic module provided by the embodiments of the present application.

[0045] Reference signs: 1000 - battery string; 1100 - battery piece; 1110 - battery body; 1111 - main busbar line; 1112 - back busbar line; 1112a - main busbar line; 1112b - auxiliary busbar line; 1113 - PAD point; 1120 - metal foil; 1200 - solder strip; 1300 - connecting part; 1310 - flat part. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0047] In the description of the present application, it should be noted that the positions or location relationships indicated by the terms "inner", "outer" 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.

[0048] 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 connected 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.

[0049] At present, the line loss of the battery piece 1100 of the shingled battery is high, and the battery piece 1100 needs to be cut into a smaller size to control the line loss, but multiple cutting will cause damage to the battery piece 1100, affecting 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 the aluminum back field will increase the probability of the warping of the battery piece 1100, and then reduce the yield of the battery piece 1100 or reduce the adaptability to the production equipment; or the increase of the amount of silver paste will increase the cost of the battery piece 1100.

[0050] To this end, the application intends to provide a battery piece 1100, which can reduce line loss and realize less cutting while considering low warping and low cost of the battery piece 1100 by arranging a metal foil 1120 on the back light surface of a battery body 1110.

[0051] FIG. 1 is a structural schematic diagram of the back light side of the battery piece 1100 provided by the application. As shown in FIG. 1, the application provides a battery piece 1100, which comprises a battery body 1110 and a metal foil 1120. The back light surface of the battery body 1110 is provided with a back surface grid line 1112. The metal foil 1120 is connected to the back surface grid line 1112.

[0052] The battery piece 1100 can realize lower line loss and further realize less cutting in the preparation process by arranging a layer of metal foil 1120 to connect the grid line on the back light side of the battery body 1110, even in the case of thinner aluminum back field, or even without aluminum back field or less silver paste material, which is conducive to reducing the loss of the battery piece 1100, and at the same time, does not cause warping or cost increase.

[0053] 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, etc. The solidification can be realized by a solidification furnace (long distance heating channel with platform adsorption, hot air circulation and temperature rising, holding and cooling functions), and a conductive connection layer is formed 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 setting 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.

[0054] In some embodiments, the connection position between the metal foil 1120 and the battery body 1110 comprises 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.

[0055] Generally, the two sides of the battery piece 1100 are also provided with cover glass, and the cover glass and the battery body 1110 are filled with adhesive film to achieve protection of the battery body 1110, and the solder strip 1200 and the metal foil 1120 are embedded in the adhesive film.

[0056] Since the metal foil 1120 is arranged to replace the solder strip 1200 on the back light side, 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.

[0057] In some embodiments, the metal foil 1120 can be selected from aluminum foil or copper foil.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Due to the metal foil 1120, the material of the grid line can be reduced under the same line loss, and correspondingly, the width and thickness of the grid line of the cell 1100 can be reduced, and the spacing can be increased.

[0064] FIGS. 2 and 3 are structural schematic diagrams of the back surface grid line 1112 provided by the embodiments of the present application. As shown in FIGS. 2 and 3, 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; and 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.

[0065] 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., and can also be any value within 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., and can also be any value within 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., and can also be any value within the range of 5 mm to 15 mm. The thickness of the auxiliary 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., and can also be any value within the range of 5 μm to 10 μm. The width of the auxiliary 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., and can also be any value within the range of 10 μm to 30 μm. The interval of the auxiliary 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., and can also be any value within the range of 1 mm to 2 mm.

[0066] FIG. 4 is a structural schematic diagram of the back surface grid line 1112 provided by the embodiments of the present application. As shown in FIG. 4, in some embodiments, the back surface grid line 1112 can be provided as only the main grid line 1112a. At this time, the current transmission path of the cell sheet 1100 is transmitted by the main grid line 1112a and the metal foil 1120. Further, the thickness of the main grid line 1112a is 3 μm to 5 μm, the width of the main grid line 1112a is 20 μm to 40 μm, and the interval of the main grid line 1112a is 1 μm to 2 μm. By controlling the thickness of the main grid line 1112a to be 3 μm to 5 μm, the width of the main grid line 1112a to be 20 μm to 40 μm, and the interval of the main grid line 1112a to be 1 μm to 2 μm, the line loss and the manufacturing cost of the cell sheet 1100 can be considered.

[0067] 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., and 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., and can also be any value in the range of 20 μm to 40 μm. The spacing of the main grid line 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., and can also be any value in the range of 1 mm to 2 mm.

[0068] FIGS. 5 and 6 are structural schematic diagrams of a battery string 1000 provided by the embodiments of the present application. As shown in FIGS. 5 and 6, based on the same aspect, the embodiments of the present application provide a battery string 1000, which includes a plurality of battery pieces 1100 provided above, a solder strip 1200 and a connecting part 1300. The battery body 1110 includes a silicon wafer substrate, a main surface grid line 1111 arranged on the light-receiving surface of the silicon wafer substrate and a back surface grid line 1112 arranged on the back light surface of the silicon wafer substrate. The solder strip 1200 is connected with the main surface grid line 1111, the metal foil 1120 is connected with the back surface grid line 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.

[0069] The battery string 1000 is implemented based on the battery piece 1100 described above, and the specific content of the battery piece 1100 can refer to the above embodiments. Since the battery string 1000 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.

[0070] 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, which can realize lower line loss in the case of thinner aluminum back field, even without aluminum back field or less silver paste material, and thus can realize less cutting in the preparation process, which is conducive to reducing the loss of the battery piece 1100, and does not cause warping or cost increase.

[0071] Please refer to Fig. 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.

[0072] Further, the connecting solder strip has a flat part 1310 connected with the metal foil 1120, and the thickness of the flat part 1310 is not more than 100 μm. Controlling the thickness of the flat part 1310 is beneficial to controlling the thickness of the back side adhesive layer, and is also beneficial to the welding of the flat part 1310 with the battery piece 1100, thereby reducing 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, the limit thickness of the flat part 1310 pressed on the solder strip 1200 is about 20 μm due to the preparation process, so the thickness of the flat part 1310 is in the preferable range of 20 μm to 100 μm which can be realized at present. When the preparation process is further optimized, the flat part 1310 can be further thinned.

[0073] 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 more than 100 μm.

[0074] Please refer to Fig. 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.

[0075] Further, the width of the overlapping area of 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 of the connecting direction of each 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.

[0076] For example, the width of the overlapping area of 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 in the range of not more than 1 mm.

[0077] Based on the same aspect, the embodiments of the present application provide a photovoltaic module, which comprises the battery string 1000 provided above.

[0078] The photovoltaic module is realized based on the above-mentioned cell string 1000, specific content of which can refer to the above-mentioned embodiments, since the photovoltaic module adopts part or all of the technical solutions of the above-mentioned embodiments, and thus at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be repeated here.

[0079] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.

[0080] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. 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; 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 back surface grid line comprises a main grid line and a sub grid line; 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 back surface grid line comprises a main grid line; 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 1-2 mm.

7. 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.

8. 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.

9. A battery string, characterized by The battery string comprises: at least two battery pieces according to any one of claims 1-8; 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 provided on the light-receiving surface of the other of the two adjacent battery pieces.

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

11. The battery string of claim 10, 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.

12. The battery string of claim 9, wherein, The connecting portion is a connecting metal foil, and the connecting metal foil and the metal foil are integrally formed.

13. The battery string of claim 12, 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.

14. A photovoltaic module, characterized by, The photovoltaic module comprises the battery string according to any one of claims 9-13.

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