A back-contact solar cell and a back-contact solar cell module

Abstract

Embodiments of the present application relate to the field of photovoltaic technology. Embodiments of the present application provide a back-contact cell and a back-contact battery module. The back-contact cell includes a body portion and grid lines disposed on the body portion. The grid lines include connecting lines and sub-grids. The connecting lines are arranged along the width direction, and the sub-grids are arranged along the length direction. The sub-grids are electrically connected to the connecting lines. The connecting lines include two first connecting lines, and the connecting line located between the first connecting lines is a second connecting line. The second connecting line has a first connecting segment located between the connecting portions. The first connecting lines are electrically connected to the second connecting lines with the same polarity through the second connecting segment. The width of the first connecting line is greater than the width of the first connecting segment, and the width of the second connecting segment is greater than the width of the first connecting segment. Through such a design, the loss of current during transmission can be reduced, which is beneficial to improving the efficiency of the back-contact cell.

Description

Technical Field

[0001] The present application relates to the technical field of photovoltaic modules, and particularly to a back-contact cell and a back-contact battery module. Background Art

[0002] With the development of technology, photovoltaic modules have become commonly used devices due to their advantages such as environmental friendliness, renewable energy, high safety, and long service life. The cells in the photovoltaic module can generate photocurrent by absorbing light to power other devices. Usually, the edge position of the cell has a relatively weak ability to collect current. During the EL test, the edge position of the cell is prone to graying, that is, the CTM performance of the cell is poor, affecting the efficiency of the cell. Summary of the Invention

[0003] Embodiments of the present application provide a back-contact cell and a back-contact battery module for improving the efficiency of the back-contact cell.

[0004] Embodiments of the present application provide a back-contact cell, and the back-contact cell includes:

[0005] A body part;

[0006] Grid lines, which are disposed on the body part;

[0007] Wherein, the grid lines include a plurality of connection lines and a plurality of sub-grid lines. Along the width direction of the back-contact cell, the connection lines are arranged in sequence. Along the length direction of the back-contact cell, the sub-grid lines are arranged in sequence. The connection lines are electrically connected to the sub-grid lines. Among the connection lines, two of the connection lines are first connection lines, and the remaining connection lines are second connection lines. Along the width direction of the back-contact cell, the first connection lines are located on the opposite sides of the back-contact cell, and the second connection lines are located between the first connection lines. The back-contact cell further includes a connection part, and the second connection lines are connected to the connection part. The second connection line includes a first connection segment, and at least part of the first connection segment is located between adjacent connection parts. Each of the second connection lines is a first-polarity connection line and a second-polarity connection line respectively, and the first-polarity connection lines and the second-polarity connection lines are arranged at intervals. The polarity of the first connection line is the same as that of the first-polarity connection line. The back-contact cell includes a second connection segment, and the first connection line is electrically connected to the nearest first-polarity connection line through the second connection segment;

[0008] The width of the first connection segment is a, the width of the first connection line is b, and the width of the second connection segment is c, and b > a, c > a.

[0009] In a possible implementation, the width of the first connection line is 50 micrometers to 150 micrometers.

[0010] In a possible implementation, the distance between the first connection line and the adjacent second connection line is 300 micrometers to 400 micrometers.

[0011] In a possible implementation, along the length direction of the back-contact cell, the pitch between the sub-gates on the opposite sides of the second connection segment is d, and the width c of the second connection segment satisfies: d - 380 micrometers ≤ c ≤ d - 300 micrometers.

[0012] In a possible implementation, the width of the second connection segment is 100 micrometers to 200 micrometers.

[0013] In a possible implementation, the width b of the first connection line and the width c of the second connection segment satisfy: c > b.

[0014] In a possible implementation, the sub-gate includes a first sub-gate and a second sub-gate. The first sub-gate is electrically connected to the first connection line, and the second sub-gate is electrically connected to the second connection line;

[0015] The width of the first sub-gate is e, the width of the second sub-gate is f, and e > f.

[0016] In a possible implementation, the width of the first sub-gate is 10 micrometers to 30 micrometers.

[0017] In a possible implementation, the width of the first connection segment is 14 micrometers to 16 micrometers, and the width of the second sub-gate is 8 micrometers to 16 micrometers.

[0018] The embodiment of the present application further provides a back-contact battery assembly, and the back-contact battery assembly includes at least one back-contact cell as described in any one of the above.

[0019] The embodiment of the present application provides a back-contact cell and a back-contact battery assembly. The back-contact cell includes a body portion and grid lines disposed on the body portion. The grid lines include connection lines and sub-gates. The connection lines are arranged along the width direction, the sub-gates are arranged along the length direction, and the sub-gates and the connection lines are electrically connected. The connection lines include two first connection lines, and the connection line located between the first connection lines is the second connection line. The second connection line has a first connection segment between the connection portions. The first connection line is electrically connected to the second connection line with the same polarity through the second connection segment. The width of the first connection line is greater than the width of the first connection segment, and the width of the second connection segment is greater than the width of the first connection segment. Through such a design, the loss of current during transmission can be reduced, which is beneficial to improving the efficiency of the back-contact cell. Description of the Drawings

[0020] To more clearly illustrate the technical solutions of the embodiments of the present application, the accompanying drawings required for the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0021] Figure 1 Schematic diagram of the back-contact cell provided by the embodiment of the present application;

[0022] Figure 2 Partial schematic diagram of the back-contact cell provided by the embodiment of the present application.

[0023] Reference numerals

[0024] 1 - Body part;

[0025] 2 - Grid line;

[0026] 21 - Connecting line;

[0027] 211 - First connecting line;

[0028] 212 - Second connecting line;

[0029] 212a - First connection segment;

[0030] 212b - First polarity connecting line;

[0031] 212c - Second polarity connecting line;

[0032] 212d - Third connection segment;

[0033] 22 - Sub-grid;

[0034] 221 - First sub-grid;

[0035] 222 - Second sub-grid;

[0036] 3 - Connection part;

[0037] 4 - Second connection segment. Detailed implementation manners

[0038] To better understand the technical solutions of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0039] It should be clear that the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0040] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0041] It should be understood that the term " / and" used herein is merely a description of the associated relationship between associated objects, indicating that three relationships may exist. For example, A / and B may represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0042] Such as Figure 1 And Figure 2As shown in the figure, an embodiment of the present application provides a back-contact solar cell. The back-contact solar cell includes a body portion 1 and grid lines 2, and the grid lines 2 are disposed on the body portion 1. The body portion 1 serves as the base of the back-contact solar cell and is usually a processed silicon wafer. The body portion 1 can absorb light and generate a photocurrent, and the grid lines 2 are used to collect the current generated by the body portion 1 and lead out the current. The grid lines 2 include a plurality of connecting lines 21 and a plurality of sub-grid lines 22. Along the width direction X of the back-contact solar cell, the connecting lines 21 are arranged in sequence. Along the length direction Y of the back-contact solar cell, the sub-grid lines 22 are arranged in sequence. The connecting lines 21 extend along the length direction Y of the back-contact solar cell, and the sub-grid lines 22 extend along the width direction X of the back-contact solar cell. The connecting lines 21 and the sub-grid lines 22 can be distributed in a grid pattern on the surface of the body portion 1. Among the plurality of connecting lines 21, two are the first connecting lines 211, and the rest are the second connecting lines 212. Along the width direction X of the back-contact solar cell, the first connecting lines 211 are located on opposite sides of the back-contact solar cell, and the second connecting lines 212 are located between the first connecting lines 211. That is, the first connecting lines 211 are located at positions close to the edges on both sides of the body portion 1, and the second connecting lines 212 are located between the two first connecting lines 211. The first connecting lines 211 and the second connecting lines 212 are located on the same side of the body portion 1. The back-contact solar cell further includes a connecting portion 3, and the connecting portion 3 is used for electrically connecting with a welding wire. The second connecting lines 212 are connected to the connecting portion 3. The second connecting lines 212 include a first connecting segment 212a, and at least a part of the first connecting segment 212a is located between adjacent connecting portions 3. The second connecting lines 212 can be divided into first-polarity connecting lines 212b and second-polarity connecting lines 212c according to the polarity, and the first-polarity connecting lines 212b and the second-polarity connecting lines 212c are distributed at intervals. That is, the second connecting line 212 adjacent to the first-polarity connecting line 212b is the second-polarity connecting line 212c, and the second connecting line 212 adjacent to the second-polarity connecting line 212c is the first-polarity connecting line 212b. The polarity of the first connecting lines 211 is the same as the polarity of the first-polarity connecting lines 212b. The back-contact solar cell further includes a second connecting segment 4, and the first connecting lines 211 are electrically connected to the nearest first-polarity connecting lines 212b through the second connecting segment 4. The width of the first connecting segment 212a is a, the width of the first connecting lines 211 is b, and the width of the second connecting segment 4 is c, and b > a, c > a.

[0043] In the solution provided by the embodiments of the present application, by thickening the first connection line 211 and the second connection segment 4, the widths of the first connection line 211 and the second connection segment 4 are both greater than the width of the first connection segment 212a. Through the thickening design, the cross-sectional areas of the first connection line 211 and the second connection segment 4 are increased, thereby reducing the resistance of the first connection line 211 and the second connection segment 4, reducing current loss, improving the uniformity of EL imaging during EL testing, and enhancing the CTM performance of the back-contact cell. Since the current loss of the first connection line 211 and the second connection segment 4 is reduced, the current collection ability of the back-contact cell for the edge position can be improved, which is beneficial to improving the overall efficiency of the back-contact cell and better meeting the actual usage requirements.

[0044] The first connection line 211 is located at the edge position of the body portion 1. When a connection portion 3 is provided on the first connection line 211 to connect with the solder tape, since the first connection line 211 is located at the edge position of the body portion 1, it is difficult to set the solder tape. Moreover, since the solder tape is located at the edge position of the back-contact cell, it is easily damaged, affecting the normal use of the back-contact cell. Therefore, by providing the second connection segment 4, the current of the first connection line 211 can be transmitted to the second connection line 212 of the same polarity, and the current is led out through the connection portion 3 provided on the second connection line 212. The first connection line 211 does not need to be directly electrically connected to the solder tape, thereby saving costs and reducing the possibility of solder tape damage.

[0045] In a possible implementation manner, the width of the first connection line 211 is 50 microns to 150 microns. The width of the first connection line 211 can be 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, 100 microns, 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, etc.

[0046] By making the width of the first connection line 211 be 50 microns to 150 microns, the resistance of the first connection line 211 can be reduced to reduce current loss. At the same time, when the width of the first connection line 211 is within a suitable range, the amount of silver paste used can be reduced, thereby reducing costs. When the width of the first connection line 211 is too wide, it will also block the body portion 1, affecting the light-receiving area of the back-contact cell. When the width of the first connection line 211 is too narrow, the loss during current transmission is relatively high. Therefore, when the width of the first connection line 211 is 50 microns to 150 microns, while reducing current loss, costs can be reduced, the efficiency of the back-contact cell can be improved, and it better meets the actual usage requirements.

[0047] Such as Figure 2As shown, in a possible implementation, the distance between the first connection line 211 and the adjacent second connection line 212 is 300 microns to 400 microns. The distance between the first connection line 211 and the second connection line 212 can be 300 microns, 310 microns, 320 microns, 330 microns, 340 microns, 350 microns, 360 microns, 370 microns, 380 microns, 390 microns, 400 microns, etc.

[0048] By making the distance between the first connection line 211 and the second connection line 212 be 300 microns to 400 microns, it is beneficial to improve the current collection ability of the back contact cell for the current at the edge position. When the distance between the first connection line 211 and the second connection line 212 is too large, the current transmission distance increases, resulting in an increase in current loss during transmission. When the distance between the first connection line 211 and the second connection line 212 is too small, it is easy to have uneven current distribution, and the risk of short - circuit will increase. Therefore, the distance between the first connection line 211 and the adjacent second connection line 212 is 300 microns to 400 microns.

[0049] As Figure 2 shown, in a possible implementation, along the length direction Y of the back contact cell, the distance between the auxiliary grids 22 on the opposite sides of the second connection segment 4 is d, and the width c of the second connection segment 4 satisfies: d - 380 microns ≤ c ≤ d - 300 microns. The width c of the second connection segment 4 can be d - 380 microns, d - 370 microns, d - 360 microns, d - 350 microns, d - 340 microns, d - 330 microns, d - 320 microns, d - 310 microns, d - 300 microns, etc.

[0050] By making the distance between the second connection segment 4 and the auxiliary grid 22 satisfy the relationship of d - 380 microns ≤ c ≤ d - 300 microns, the width of the second connection segment 4 can be increased to reduce the resistance of the second connection segment 4, thereby reducing current loss. At the same time, it can also make the second connection segment 4 have a sufficient distance from the adjacent auxiliary grid 22 to reduce the possibility of short - circuit between the second connection segment 4 and the auxiliary grid 22, so as to improve the working stability and working efficiency of the back contact cell, which is more in line with the actual use requirements.

[0051] In a possible implementation, the distance between the auxiliary grids 22 connected to the same connection line 21 can also be d. Such a setting method is beneficial to the uniform distribution of the auxiliary grids 22 in the body part, thereby being beneficial to improving the current collection efficiency.

[0052] As Figure 2As shown, in a possible implementation, the width of the second connection segment 4 can be from 100 microns to 200 microns. The width of the second connection segment 4 can be 100 microns, 110 microns, 120 microns, 130 microns, 140 microns, 150 microns, 160 microns, 170 microns, 180 microns, 190 microns, 200 microns, etc.

[0053] When the width of the second connection segment 4 is too small, the resistance of the second connection segment 4 is large. According to Joule's law: , where Q is the heat, I is the current, R is the resistance, and t is the time. When the resistance of the second connection segment 4 increases, it will cause an increase in the heat per unit time, so it will cause an increase in current loss, thus affecting the efficiency of the back-contact cell. When the width of the second connection segment 4 is too large, the cost of materials such as silver paste increases, and it also leads to increased welding difficulty. The too-wide second connection segment 4 will also affect the light-receiving area of the back-contact cell, thus resulting in a reduction in the efficiency of the back-contact cell. Moreover, when the width of the second connection segment 4 is too large, it is also easy to come into contact with the adjacent secondary grid 22, resulting in a short-circuit situation in the back-contact cell. Therefore, the width of the second connection segment 4 can be from 100 microns to 200 microns, which can reduce current loss while also reducing costs and improving the efficiency of the back-contact cell, making it more in line with the actual usage requirements.

[0054] As Figure 2 shown, in a possible implementation, the width b of the first connection line 211 and the width c of the second connection segment 4 satisfy c > b.

[0055] The second connection segment 4 is used to lead out the current of the first connection segment 212a. By making the width of the second connection segment 4 greater than the width of the first connection line 211, the resistance of the second connection segment 4 can be further reduced, which is beneficial to reducing current loss during the current transmission process, thus improving the efficiency of the back-contact cell.

[0056] As Figure 2 shown, in a possible implementation, the secondary grid 22 includes a first secondary grid 221 and a second secondary grid 222. The first secondary grid 221 is electrically connected to the first connection line 211, and the second secondary grid 222 is electrically connected to the second connection line 212. The width of the first secondary grid 221 is e, the width of the second secondary grid 222 is f, and e > f.

[0057] The first sub-grid 221 is connected to the first connection segment 212a located at the edge position of the back-contact cell, and is used to collect the current at the edge position of the back-contact cell. By making the width of the first sub-grid 221 greater than the width of the second sub-grid 222, the resistance of the first sub-grid 221 can be reduced, thereby reducing current loss and improving the current collection ability of the first sub-grid 221 for the edge position of the back-contact cell. Therefore, in the EL test, the graying of the edge position of the back-contact cell can be improved.

[0058] In a possible implementation, the width of the first sub-grid 221 is 10 μm to 30 μm. The width of the first sub-grid 221 can be 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, etc.

[0059] When the width of the first sub-grid 221 is too small, the resistance of the first sub-grid 221 is relatively large. Therefore, the current loss is large, resulting in a decrease in the efficiency of the back-contact cell. When the width of the first sub-grid 221 is too large, the cost of the first sub-grid 221 increases, and it is easy to contact other grid lines 2, resulting in a short circuit in the back-contact cell. Therefore, the width of the first sub-grid 221 being 10 μm to 30 μm can improve the current collection ability of the first sub-grid 221, reduce current loss, while also reducing costs and improving the efficiency of the back-contact cell.

[0060] In a possible implementation, the width of the first connection segment 212a is 14 μm to 16 μm, and the width of the second sub-grid 222 is 8 μm to 16 μm. The width of the first connection segment 212a can be 14.0 μm, 14.2 μm, 14.4 μm, 14.6 μm, 14.8 μm, 15.0 μm, 15.2 μm, 15.4 μm, 15.6 μm, 15.8 μm, 16.0 μm, etc. The width of the second sub-grid can be 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, etc.

[0061] The first connection segment 212a can serve as the main grid or a part of the main grid and is used to lead out the current collected by the secondary grid 22. When the width of the first connection segment 212a is too small, the resistance of the first connection segment 212a will increase, and the heat generated during current transmission will increase, resulting in an increase in current loss. When the width of the first connection segment 212a is too large, the shielding area of the first connection segment 212a for the body portion 1 is relatively large, which will affect the light-receiving area of the back-contact solar cell, resulting in a relatively low efficiency of the back-contact solar cell. By making the width of the first connection segment 212a 14 to 16 micrometers, while reducing current loss, it is also possible to reduce the shielding of the first connection segment 212a for the body portion 1, which is beneficial to improving the efficiency of the back-contact solar cell.

[0062] When the width of the second secondary grid 222 is 8 to 16 micrometers, it can improve the current collection ability of the second secondary grid 222, which is beneficial to improving the efficiency of the back-contact solar cell and better meets the actual usage requirements.

[0063] In a possible implementation manner, the width of the first connection line 211 is 75 micrometers, and the width of the second connection segment 4 is 100 micrometers. That is, the width of the second connection segment 4 is greater than the width of the first connection line 211, the width of the first connection line 211 is greater than the width of the first secondary grid 221, and the width of the first secondary grid 221 is greater than the width of the second secondary grid 222.

[0064] In the related art, the width of the first connection line 211 and the width of the second connection segment 4 are usually the same as the width of the first connection segment 212a, and the widths of the first secondary grid 221 and the second secondary grid 222 are also the same. The first connection line 211 located at the edge position needs to converge the current to the second connection line 212 with the same polarity. The current collected by the second connection line 212 can be led out through the connection portion 3 and the solder strip. The transmission distance of the current in the first connection line 211 is relatively long, and the current is relatively large. Therefore, the current loss generated when the current is transmitted in the first connection line 211 is also relatively large. When performing an EL test on the back-contact solar cell, graying will occur at the edge position, that is, the CTM performance of the back-contact solar cell is poor, and the efficiency of the back-contact solar cell is relatively low.

[0065] In the solution provided by the embodiments of the present application, by thickening the first connection line 211, the second connection segment 4, and the first sub-grid 221, the resistance of the first connection line 211, the second connection segment 4, and the first sub-grid 221 can be reduced. According to Joule's law, when the resistance decreases, the heat generated per unit time decreases. Therefore, by thickening the first connection line 211, the second connection segment 4, and the first sub-grid 221, the loss of current during transmission can be reduced, thereby ensuring the uniformity of EL imaging and improving the situation where the edge position of the back-contact cell turns gray during EL testing, thereby improving the CTM of the back-contact cell and increasing the efficiency of the back-contact cell. The second connection segment 4 serves as a through-line of the back-contact cell, and is used to converge the current of the first connection line 211 to the second connection line 212 and lead out the current through the connection portion 3. That is, the current of the first connection line 211 needs to converge from the second connection segment 4 to the second connection line 212. Therefore, the second connection segment 4 that plays a current-converging role needs to be wider than the width of the first connection line 211 to reduce current loss.

[0066] The width of the first sub-grid 221 being greater than the width of the second sub-grid 222 can improve the current collection ability of the first sub-grid 221 for the edge position of the back-contact cell. At the same time, by increasing the width of the first sub-grid 221, the resistance of the first sub-grid 221 can also be reduced, thereby reducing the heat generated during current transmission and reducing current loss. By using the first connection line 211 and the second connection segment 4 with larger widths, the loss of current during transmission can be further reduced, which is beneficial to increasing the efficiency of the back-contact cell. The second connection line 212 may further include a third connection segment 212d. The third connection segment 212d is at least provided at one end of the first connection segment 212a, and the width of the third connection segment 212d is greater than the width of the first connection segment 212a. And in a possible implementation manner, the width of the third connection segment 212d may be greater than the width of the first connection line 211, and the width of the third connection segment 212d is greater than the width of the second connection segment 4.

[0067] By providing the third connection segment 212d at at least one end of the first connection segment 212a, the second connection line 212 can be formed into a structure with a wider end and a narrower middle. Such a design is beneficial to improving the current collection ability and transmission ability of the grid line 2 for the edge position of the back-contact cell, thereby being beneficial to increasing the efficiency of the back-contact cell and better meeting the actual usage requirements.

[0068] The embodiments of the present application also provide a back-contact battery assembly, which includes at least one back-contact battery cell. The back-contact battery cell can be the back-contact battery cell involved in any of the above embodiments. Since the back-contact battery cell has the above technical effects, the back-contact battery assembly including the back-contact battery cell also has corresponding technical effects, which will not be elaborated here.

[0069] The back-contact battery assembly may further include structures such as a first cover plate, a second cover plate, a first adhesive film, and a second adhesive film. A plurality of back-contact battery cells are electrically connected to form a back-contact battery string, and a plurality of back-contact battery strings are electrically connected to form a back-contact battery array. Along the thickness direction of the back-contact battery assembly, the first adhesive film and the second adhesive film are located on opposite sides of the back-contact battery array. The first cover plate is located on the side of the first adhesive film away from the back-contact battery array, and the second cover plate is located on the side of the second adhesive film away from the back-contact battery array. The first cover plate and the second cover plate are located on the surface of the back-contact battery assembly and can protect the back-contact battery assembly. The first adhesive film and the second adhesive film can play a buffering role to reduce the possibility of hidden cracks in the back-contact battery cells during lamination and when being collided, thus contributing to improving the service life of the back-contact battery assembly.

[0070] Adjacent back-contact battery cells can be connected by solder tapes. The sub-grid 22 is used to collect the photo-generated current generated by the body part, and the connection line 21 is used to collect the current of the sub-grid 22. The connection line 21 is connected to the solder tape to be able to lead out the current.

[0071] In a possible implementation manner, adjacent battery cells can also be connected using conductive adhesive. The conductive adhesive has good electrical conductivity and adhesiveness. The conductive adhesive is coated on the electrodes of the battery cells, and then through pressing and curing, a conductive path can be formed to achieve electrical connection. Connecting through the conductive adhesive can reduce the influence of thermal stress and the possibility of mechanical damage on the back-contact battery cells during the connection process, which is beneficial to improving the reliability and stability of the back-contact battery assembly. In the actual production process, the solder tape and the conductive adhesive can be combined to use to save costs and improve reliability.

[0072] The first cover plate and the second cover plate have relatively high structural strength, providing a certain mechanical strength and rigidity for the back-contact battery assembly to protect the adhesive film, back-contact battery cells, etc. inside the back-contact battery assembly, reducing the influence of environmental factors such as rain, sand, and dust on the back-contact battery assembly, and can reduce the possibility of the back-contact battery assembly being corroded, worn, and aged, thus contributing to extending the service life of the back-contact battery assembly.

[0073] When one side of the back-contact battery component is the light-receiving side and the other side is the backlight side, the first cover plate is located on the light-receiving side, and the second cover plate is located on the backlight side. The material of the first cover plate is a light-transmitting material, and the material of the second cover plate is a light-reflecting material or a reflective layer is provided. Light can pass through the first cover plate and the first encapsulant film to reach the back-contact cell, and is absorbed by the back-contact cell to generate photo-generated current. The light not absorbed by the back-contact cell can be reflected by the second cover plate after passing through the second encapsulant film, so that the light can be transmitted to the back-contact cell again, enabling the back-contact cell to absorb the light again, thereby improving the light absorption efficiency of the back-contact cell, and further improving the efficiency of the back-contact cell.

[0074] When both sides of the back-contact battery are light-receiving sides, the materials of the first cover plate and the second cover plate are both light-transmitting materials. Such a design can help increase the light-receiving area of the back-contact battery component, thereby helping to improve the efficiency.

[0075] The material of the cover plate can be tempered glass, etc. While having good strength, it also has good light transmittance. When tempered glass is used as the second cover plate, reflection can be achieved by setting a reflective film, a reflective coating, etc. on the surface of the tempered glass to improve the efficiency.

[0076] The first encapsulant film and the second encapsulant film can be EVA encapsulant film, POE encapsulant film, EPE encapsulant film (EVA-POE-EVA co-extruded encapsulant film), etc. The encapsulant film is located between the cover plate and the cell, and can play a role in bonding and fixing, so as to help the various components of the back-contact battery component form a whole, and can reduce the possibility of delamination and detachment during the use of the back-contact battery component. The encapsulant film can also play a sealing role, reducing the possibility of external water vapor, oxygen and other substances entering the interior of the back-contact battery component, thereby reducing the possibility of the back-contact cell and other components being corroded and oxidized, and being beneficial to extending the service life and reliability of the back-contact battery component.

[0077] The encapsulant film can also refract and scatter light to some extent, enabling the light to be better transmitted and utilized inside the component, which is conducive to improving the light absorption efficiency of the back-contact solar cell and the efficiency of the back-contact solar cell module, and better meeting the actual usage requirements. The solar cell provided in the embodiment of the present application is a back-contact solar cell, and the positive and negative electrodes of the back-contact solar cell are both arranged on the back surface of the body part, that is, the light-back side of the back-contact solar cell. Such a design can reduce the occlusion of the light-receiving side of the body part 1 by the grid lines 2, which is conducive to increasing the light-receiving area of the body part 1, thereby improving the photoelectric conversion efficiency. At the same time, since the electrodes are concentrated on the same side of the body part 1, when collecting current, the current transmission path is shorter, which is conducive to reducing the loss during current transmission, improving the fill factor and conversion efficiency of the solar cell, and better meeting the actual usage requirements. By arranging the electrodes on the light-back side of the body part 1, the possibility of the electrodes being corroded and damaged in outdoor environments can be reduced. By arranging the electrodes on the light-back side, the influence of light and ultraviolet rays on the electrodes can be reduced, the aging and performance degradation rate of the electrodes can be reduced, which is conducive to extending the service life of the solar cell and improving the reliability of the solar cell. There are usually no electrode grid lines on the front surface of the back-contact solar cell. Therefore, the possibility of stress concentration caused by differences in the coefficient of thermal expansion can be reduced, and the possibility of cracking and breakage of the back-contact solar cell during use can be reduced.

[0078] The embodiment of the present application provides a back-contact solar cell and a back-contact solar cell module. The back-contact solar cell includes a body part 1 and grid lines 2 arranged on the body part 1. The grid lines 2 include connecting lines 21 and sub-grids 22. The connection points are arranged along the width direction, and the sub-grids 22 are arranged along the length direction. The connecting line 21 includes two first connecting lines 211, and the connecting line 21 between the first connecting lines 211 is the second connecting line 212. The sub-grid 22 includes a first sub-grid 221 and a second sub-grid 222. The first sub-grid 221 is electrically connected to the first connecting line 211, and the second sub-grid 222 is electrically connected to the second connecting line 212. The second connecting line 212 has a first connection segment 212a located between the connection parts 3, and the first connecting line 211 is electrically connected to the second connecting line 212 with the same polarity through the second connection segment 4. The width of the first connecting line 211 is greater than the width of the first connection segment 212a, and the width of the second connection segment 4 is greater than the width of the first connection segment 212a. Through such a design, the loss of current during transmission can be reduced, which is conducive to improving the efficiency of the back-contact solar cell.

[0079] The above is only the specific implementation manner of the embodiment of the present application, but the protection scope of the embodiment of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the embodiment of the present application should be covered by the protection scope of the embodiment of the present application. Therefore, the protection scope of the embodiment of the present application should be subject to the protection scope of the claims.

Claims

1. A back contact solar cell, characterized in that, The back-contact solar cell includes: a body portion (1); grid lines (2) disposed on the body portion (1); wherein the grid lines (2) include a plurality of connecting lines (21) and a plurality of sub-grid lines (22). Along the width direction (X) of the back-contact solar cell, the connecting lines (21) are arranged in sequence. Along the length direction (Y) of the back-contact solar cell, the sub-grid lines (22) are arranged in sequence. The connecting lines (21) are electrically connected to the sub-grid lines (22). Among the connecting lines (21), two of the connecting lines (21) are first connecting lines (211), and the remaining connecting lines (21) are second connecting lines (212). Along the width direction (X) of the back-contact solar cell, the first connecting lines (211) are located on opposite sides of the back-contact solar cell, and the second connecting lines (212) are located between the first connecting lines (211). The back-contact solar cell further includes a connecting portion (3), and the second connecting lines (212) are connected to the connecting portion (3). The second connecting lines (212) include a first connecting segment (212a), and at least a part of the first connecting segment (212a) is located between adjacent connecting portions (3). Each of the second connecting lines (212) is respectively a first-polarity connecting line (212b) and a second-polarity connecting line (212c), and the first-polarity connecting lines (212b) and the second-polarity connecting lines (212c) are arranged at intervals. The polarity of the first connecting lines (211) is the same as that of the first-polarity connecting lines (212b). The back-contact solar cell includes a second connecting segment (4), and the first connecting lines (211) are electrically connected to the nearest first-polarity connecting lines (212b) through the second connecting segment (4); The width of the first connecting segment (212a) is a, the width of the first connecting line (211) is b, and the width of the second connecting segment (4) is c, and b > a, c > a.

2. The back contact cell according to claim 1, wherein, The width of the first connecting line (211) is 50 micrometers to 150 micrometers.

3. The back-contact cell according to claim 1, wherein The distance between the first connecting line (211) and the adjacent second connecting line (212) is 300 micrometers to 400 micrometers.

4. The back contact cell according to claim 1, characterized in that, Along the length direction (Y) of the back-contact solar cell, the distance between the sub-grid lines (22) on opposite sides of the second connecting segment (4) is d, and the width c of the second connecting segment (4) satisfies: d - 380 micrometers ≤ c ≤ d - 300 micrometers.

5. The back-contact solar cell according to claim 1, wherein, The width of the second connecting segment (4) is 100 micrometers to 200 micrometers.

6. The back-contact cell according to claim 1, characterized in that, The width b of the first connecting line (211) and the width c of the second connecting segment (4) satisfy: c > b.

7. The back-contact cell according to any one of claims 1 to 6, characterized in that, The sub-grid lines (22) include first sub-grid lines (221) and second sub-grid lines (222). The first sub-grid lines (221) are electrically connected to the first connecting lines (211), and the second sub-grid lines (222) are electrically connected to the second connecting lines (212); The width of the first sub-grid line (221) is e, and the width of the second sub-grid line (222) is f, and e > f.

8. The back contact solar cell according to claim 7, wherein The width of the first sub-grid (221) is from 10 microns to 30 microns.

9. The back contact solar cell according to claim 7, characterized in that, The width of the first connection segment (212a) is from 14 microns to 16 microns, and the width of the second sub-grid (222) is from 8 microns to 16 microns.

10. A back-contact battery component, characterized in that, The back-contact battery assembly includes at least one back-contact battery cell according to any one of claims 1 to 9.

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