Interdigitated back contact battery, its electrode structure and solar cell module

Abstract

The present application provides an interdigitated back contact battery, an electrode structure thereof, and a solar cell module. In a first aspect of the present application, an electrode structure of an interdigitated back contact battery is provided, including: main grid lines, including M positive main grid lines and N negative main grid lines arranged at intervals in the transverse direction, and fine grid lines, including a plurality of positive fine grid lines and a plurality of negative fine grid lines arranged at intervals in the longitudinal direction. Among them, the M positive main grid lines equally divide each positive fine grid line in the transverse direction and each positive main grid line is electrically connected to the plurality of positive fine grid lines. The N negative main grid lines equally divide each negative fine grid line in the transverse direction and each negative main grid line is electrically connected to the plurality of negative fine grid lines, and 1 ≤ M < N. For the interdigitated back contact battery provided in the first aspect of the present application, the positive main grid lines and the negative main grid lines can collect the current generated by the interdigitated back contact battery more evenly, reduce the power loss during the use of the interdigitated back contact battery, and reduce the production cost of the battery.

Description

Technical Field

[0001] This application relates to the technical field of solar cells, and particularly to an interdigitated back contact cell, an electrode structure thereof, and a solar cell module. Background Art

[0002] In the electrode structure of a general interdigitated back contact cell, the arrangement mode of the main grid lines is likely to cause relatively large power loss, resulting in a decrease in the efficiency of the interdigitated back contact cell.

[0003] Therefore, there is an urgent need for a new interdigitated back contact cell, an electrode structure thereof, and a solar cell module. Summary of the Invention

[0004] In a first aspect of this application, an electrode structure of an interdigitated back contact cell is provided, including:

[0005] Main grid lines, including M positive main grid lines and N negative main grid lines arranged at intervals in the transverse direction,

[0006] Fine grid lines, including multiple positive fine grid lines and multiple negative fine grid lines arranged at intervals in the longitudinal direction,

[0007] Wherein, the M positive main grid lines equally divide each positive fine grid line in the transverse direction and each positive main grid line is electrically connected to multiple positive fine grid lines, the N negative main grid lines equally divide each negative fine grid line in the transverse direction and each negative main grid line is electrically connected to multiple negative fine grid lines, and 1 ≤ M < N.

[0008] For the interdigitated back contact cell provided in the first aspect of this application, the positive main grid lines and the negative main grid lines can collect the current generated by the interdigitated back contact cell more evenly, reduce the power loss during the use of the interdigitated back contact cell. At the same time, the reduction in the number of positive main grid lines can reduce the consumption of silver paste for the electrodes, reduce the number of silver solder joints, and reduce the production cost of the battery.

[0009] In some optional embodiments of the first aspect of this application, in the transverse direction, negative main grid lines are adjacently arranged on both sides of any positive main grid line.

[0010] In some optional embodiments of the first aspect of this application, one of M and N is odd and the other is even.

[0011] In some optional embodiments of the first aspect of this application, both M and N are odd or both are even, and M and N satisfy the following relationship:

[0012] (N + 1) / (M + 1) ≠ positive integer.

[0013] In some alternative embodiments of the first aspect of the present application, the M positive main grid lines include a central positive main grid line, and the connection lines between the central positive main grid line and the center points of each positive fine grid line coincide.

[0014] In some alternative embodiments of the first aspect of the present application, the line width of the main grid line ranges from 0.05 mm to 3 mm, and the line widths of the positive main grid line and the negative main grid line are equal.

[0015] In some alternative embodiments of the first aspect of the present application, the positive fine grid lines include a plurality of aluminum fine grid segments arranged at intervals in the transverse direction;

[0016] The electrode structure further includes a silver pad, which is arranged on the same layer as the aluminum fine grid segment. In the transverse direction, the silver pad overlaps with two adjacent aluminum fine grid segments in the positive fine grid line, so that multiple aluminum fine grid segments in the positive fine grid line are electrically connected;

[0017] The positive main grid line is located on one side of the silver pad and is vertically connected to multiple positive fine grid lines through a plurality of silver pads in the longitudinal direction.

[0018] In some alternative embodiments of the first aspect of the present application, the overlapping width between the silver pad and the aluminum fine grid segment is from 0.1 mm to 0.5 mm.

[0019] In some alternative embodiments of the first aspect of the present application, in the transverse direction, the silver pad corresponds to one positive fine grid line, and both sides of the silver pad overlap two aluminum fine grid segments belonging to the same positive fine grid line respectively. Or, in the transverse direction, the silver pad corresponds to multiple positive fine grid lines, and both sides of the silver pad overlap multiple aluminum fine grid segments belonging to different positive fine grid lines respectively.

[0020] In some alternative embodiments of the first aspect of the present application, an overlapping structure is formed at the overlapping portion between the aluminum fine grid segment and the silver pad. The overlapping structure includes a first overlapping portion of the silver pad and a second overlapping portion of the aluminum fine grid segment. Among them, the first overlapping portion is closer to the positive main grid line than the second overlapping portion, or the second overlapping portion is closer to the positive main grid line than the first overlapping portion.

[0021] In some alternative embodiments of the first aspect of the present application, in the transverse direction, the overlapping structure is arranged at intervals from the positive main grid line, and the positive main grid line is a silver grid line.

[0022] The second aspect of the present application provides an interdigitated back contact battery, and the electrode structure provided by the first aspect of the present application is arranged on the backlight surface of the interdigitated back contact battery.

[0023] For the interdigitated back contact battery provided by the second aspect of the present application, the power loss during use is reduced, the consumption of silver paste is small, the production cost is reduced, and the open circuit voltage Voc and fill factor FF of the battery are improved.

[0024] The third aspect of the present application provides a solar cell module, including an interdigitated back contact cell string, which is formed by connecting a plurality of interdigitated back contact cells provided by the second aspect of the present application in series with each other.

[0025] The solar cell module provided by the third aspect of the present application requires less silver paste and has a low manufacturing cost, and the electrical performance of the solar cell module is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the 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 drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a schematic structural diagram of an embodiment of the electrode structure of the interdigitated back contact cell in the first aspect of the present application;

[0028] Figure 2 It is a schematic structural diagram of another embodiment of the electrode structure of the interdigitated back contact cell in the first aspect of the present application;

[0029] Figure 3 It is Figure 1 The top view of the layout structure of the positive main grid line and part of the fine grid lines in an embodiment shown;

[0030] Figure 4 It is Figure 3 in A The enlarged structural view after omitting the positive main grid line at the position;

[0031] Figure 5 It is Figure 4 The cross-sectional view along the E-E direction in;

[0032] Figure 6 It is Figure 2 The top view of the layout structure of the positive main grid line and part of the fine grid lines in another embodiment shown;

[0033] Figure 7 It is Figure 3 in A The cross-sectional view along the transverse direction including an example of the positive main grid line at the position;

[0034] Figure 8 It is Figure 3 in A The cross-sectional view along the transverse direction including another example of the positive main grid line at the position;

[0035] Figure 9It is a schematic structural diagram of an embodiment of an interdigitated back contact battery in the second aspect of the present application;

[0036] Figure 10 It is a schematic structural diagram of another embodiment of an interdigitated back contact battery in the second aspect of the present application;

[0037] Figure 11 It is a schematic structural diagram of an interdigitated back contact battery in Comparative Example 1;

[0038] Figure 12 It is a schematic structural diagram of the electrode structure of the interdigitated back contact battery in Comparative Example 1.

[0039] Description of the reference numerals:

[0040] 11 - P - type silicon substrate; 12 - P - type region; 13 - N - type region; 14 - passivation and antireflection layer; 15 - positive fine grid line; 15a - aluminum fine grid segment; 15b - silver pad; 151 - first overlapping portion; 152 - first overlapping portion; 16 - negative fine grid line; 17 - positive main grid line; 18 - negative main grid line; insulating material - 19;

[0041] Overlapping width - W;

[0042] X - horizontal;

[0043] Y - vertical. Detailed implementation manners

[0044] Next, the technical solutions of the present application will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0045] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0046] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0047] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] An interdigitated back contact (IBC) cell is a cell in which both the positive electrode and the negative electrode contact electrodes are placed on the back surface (non-light-receiving surface) of the cell, and the positive electrode and the negative electrode are arranged in an interdigitated manner on the backlight surface of the cell. There is no metal electrode blocking on the light-receiving surface of the cell, thereby effectively increasing the short-circuit current of the cell and improving the energy conversion efficiency of the cell.

[0049] The inventors have found in the long-term and in-depth research on interdigitated back contact cells that the positive main grid line and the negative main grid line in a general interdigitated back contact cell both appear in pairs, and the distance between the positive main grid line and the negative main grid line is relatively short. No matter which of the above wiring methods is adopted for the positive main grid line and the negative main grid line in the electrode structure of the interdigitated back contact cell, it will cause a large power loss of the interdigitated back contact cell due to the uneven collection of the current generated by the main grid line on the solar cell, resulting in the problem of the efficiency decline of the interdigitated back contact cell.

[0050] In the prior art, the positive main grid line and the negative main grid line in the interdigitated back contact cell are usually located on opposite sides of the same surface in the solar cell. Or, the positive main grid line and the negative main grid line appear in pairs, that is, the distance between the positive main grid line and the negative main grid line is very short.

[0051] The positive main grid line and the negative main grid line usually have the same structure (that is, the length and width of the grid line are the same), and due to the large number and large width of the main grids, the silver paste consumption of the interdigitated back contact cell is high, which limits the large-scale mass production of the interdigitated back contact cell.

[0052] In view of this, the present application is proposed.

[0053] As Figure 1 and Figure 2 shown, the first aspect of the present application provides an electrode structure of an interdigitated back contact cell, including:

[0054] The main grid lines include M positive main grid lines 17 and N negative main grid lines 18 arranged at intervals along the transverse direction X.

[0055] The fine grid lines include multiple positive fine grid lines 15 and multiple negative fine grid lines 16 arranged at intervals along the longitudinal direction Y.

[0056] Among them, the M positive main grid lines 17 equally divide each positive fine grid line 15 in the transverse direction X, and each positive main grid line 17 is electrically connected to the multiple positive fine grid lines 15. The N negative main grid lines 18 equally divide each negative fine grid line 16 in the transverse direction X, and each negative main grid line 18 is electrically connected to the multiple negative fine grid lines 16, and 1 ≤ M < N.

[0057] For the interdigitated back contact battery provided in the first aspect of the present application, each positive fine grid line 15 is equally divided by M positive main grid lines 17 in the transverse direction X. The positive main grid lines 17 can collect the current on all positive fine grid lines 15 more evenly. Each negative fine grid line 16 is equally divided by N negative main grid lines 18 in the transverse direction X. The negative fine grid lines 16 can collect the current on all negative fine grid lines 16 more evenly, so that the positive main grid lines 17 and the negative main grid lines 18 can collect the current generated by the interdigitated back contact battery more evenly, reducing the power loss during the use of the interdigitated back contact battery. At the same time, the reduction in the number of positive main grid lines 17 can reduce the consumption of silver paste for electrodes and lower the production cost of the battery.

[0058] In the first aspect of the present application, the transverse direction X refers to the extension direction of the fine grid lines, and the longitudinal direction Y refers to the extension direction of the main grid lines.

[0059] In the electrode structure provided in the first aspect of the present application, the positive main grid lines 17 and the negative main grid lines 18 are arranged at intervals.

[0060] In some embodiments of the first aspect of the present application, in the longitudinal direction Y, the multiple positive fine grid lines 15 and the multiple negative fine grid lines 16 are alternately arranged at intervals and are located in the same fine grid line wiring layer. The multiple positive fine grid lines 15 are parallel to each other, and the multiple negative fine grid lines 16 are also parallel to each other. Each positive main grid line 17 is electrically connected to the multiple positive fine grid lines 15, and each negative main grid line 18 is electrically connected to the multiple negative fine grid lines 16 to collect the current generated by the interdigitated back contact battery.

[0061] In the first aspect of the present application, the M positive main grid lines 17 equally divide each positive fine grid line 15 in the transverse direction X, that is, each positive fine grid line 15 is electrically connected to the M positive main grid lines 17 and is equally divided into M + 1 segments by the M positive main grid lines 17.

[0062] In the first aspect of the present application, the N negative main grid lines 18 evenly divide the negative fine grid lines 16 in the horizontal direction X, that is, each negative fine grid line 16 is electrically connected to the N negative main grid lines 18 and is evenly divided into N + 1 segments by the N negative main grid lines 18.

[0063] In some embodiments of the first aspect of the present application, the M positive main grid lines 17 and the N negative main grid lines 18 are located on the same main grid line wiring layer, and this main grid line wiring layer is located on one side of the above-mentioned fine grid line wiring layer. Each positive main grid line 17 extends along the longitudinal direction Y, is electrically connected to multiple positive fine grid lines 15 and is insulated from each negative fine grid line 16 through the insulating material 19. Each negative main grid line 18 extends along the longitudinal direction Y, is electrically connected to multiple negative fine grid lines 16 and is insulated from each positive fine grid line 15 through the insulating material 19.

[0064] In some alternative embodiments of the first aspect of the present application, in the horizontal direction X, negative main grid lines 18 are adjacently arranged on both sides of any positive main grid line 17.

[0065] In these alternative embodiments, on both sides of any positive main grid line 17, it is adjacent to and spaced from one negative main grid line 18.

[0066] In some alternative embodiments of the first aspect of the present application, both M and N are odd numbers or both are even numbers, and M and N satisfy the following relationship:

[0067] (N + 1) / (M + 1) ≠ positive integer.

[0068] In these embodiments, the positive main grid lines and the negative main grid lines do not coincide. In the case of avoiding short circuits, the current generated by the interdigitated back contact battery can be collected more evenly, reducing the power loss during the use of the interdigitated back contact battery.

[0069] In some alternative embodiments of the first aspect of the present application, one of M and N is an odd number and the other is an even number.

[0070] In some examples of these embodiments, M is an odd number and N is an even number.

[0071] As Figure 1 shown, in some specific examples of these embodiments, M takes the value of 1 and N takes the value of 4. In these embodiments, one positive main grid line 17 divides each positive fine grid line 15 into two segments, and four negative main grid lines 18 divide each negative fine grid line 16 into five segments.

[0072] As Figure 2 shown, in some other specific examples of these embodiments, M takes the value of 3 and N takes the value of 4. In these embodiments, one positive main grid line 17 divides each positive fine grid line 15 into four segments, and four negative main grid lines 18 divide each negative fine grid line 16 into five segments.

[0073] In some specific examples of these embodiments, M is 3 and N is 6, which are not shown in the figure.

[0074] In some optional embodiments of the first aspect of the present application, the M positive main grid lines 17 include a central positive main grid line 17, and the connection line between the central positive main grid line 17 and the center points of each positive fine grid line 15 coincides.

[0075] In some optional embodiments of the first aspect of the present application, the line width of the main grid line ranges from 0.05 mm to 3 mm, and the line widths of the positive main grid line 17 and the negative main grid line 18 are equal.

[0076] As Figures 3 to 6 shown, in some optional embodiments of the first aspect of the present application, the positive fine grid line 15 includes a plurality of aluminum fine grid segments 15a arranged at intervals along the transverse direction X. The electrode structure further includes a silver pad 15b, which is arranged on the same layer as the aluminum fine grid segment 15a. On the transverse direction X, the silver pad 15b overlaps with two adjacent aluminum fine grid segments 15a in the positive fine grid line 15, so that multiple aluminum fine grid segments 15a in the positive fine grid line 15 are electrically connected. The positive main grid line 17 is located on one side of the silver pad 15b and is vertically connected to multiple positive fine grid lines 15 through a plurality of silver pads 15b in the longitudinal direction Y.

[0077] In these optional embodiments, the positive fine grid line 15 adopts a plurality of aluminum fine grid segments 15a and silver pads 15b to form an electrical connection structure, which is beneficial to reducing the overlap area at the overlap of the general all-aluminum positive fine grid line 15 and the all-silver positive main grid line 17, thereby reducing the metal compound at the overlap of the positive fine grid line 15 and the positive main grid line 17, improving the open-circuit voltage Voc and fill factor FF of the interdigitated back-contact battery, and optimizing the performance of the interdigitated back-contact battery.

[0078] In these embodiments, each positive fine grid line 15 includes a plurality of aluminum fine grid segments 15a arranged at intervals along the transverse direction X. On the transverse direction X, every two adjacent aluminum fine grid segments 15a in each positive fine grid line 15 are overlapped through a silver pad 15b, that is, K (K>1) aluminum fine grid segments 15a in each positive fine grid line 15 are electrically connected through K-1 silver pads 15b. In some specific examples, the positive main grid line 17 is a silver grid line, the positive main grid line 17 is located on one side of the silver pad 15b and is in direct contact with the silver pad 15b, and is vertically connected to multiple positive fine grid lines 15 through a plurality of silver pads 15b in the longitudinal direction Y.

[0079] In some optional embodiments of the first aspect of the present application, the overlap width W between the silver pad 15b and the aluminum fine grid segment 15a is 0.1 mm to 0.5 mm.

[0080] In these alternative embodiments, when the overlapping width w between the silver pad 15b and the aluminum fine grid segment 15a satisfies the above value range, it can better ensure that the entire positive fine grid line 15 is in an electrically conductive state during the operation of the interdigitated back contact battery, ensuring the normal and stable output of the current of the interdigitated back contact battery.

[0081] Please also refer to Figure 3 and Figure 6 In some alternative embodiments of the first aspect of the present application, in the horizontal direction X, the silver pad 15b corresponds to one positive fine grid line 15, and both sides of the silver pad 15b overlap two aluminum fine grid segments 15a belonging to the same positive fine grid line 15 respectively. That is, in the horizontal direction X, both sides of each silver pad 15b only correspond to overlapping two adjacent aluminum fine grid segments 15a in the same positive fine grid line 15.

[0082] In some other alternative embodiments of the first aspect of the present application, in the horizontal direction X, the silver pad 15b corresponds to multiple positive fine grid lines 15, and both sides of the silver pad 15b overlap multiple aluminum fine grid segments 15a belonging to different positive fine grid lines 15 respectively. That is, in the horizontal direction X, each silver pad 15b corresponds to multiple positive fine grid lines 15, and two adjacent aluminum fine grid segments 15a belonging to the same positive fine grid line 15 are respectively overlapped on opposite sides of the same silver pad 15b, which is not shown in the figure.

[0083] As Figure 7 shown, in an example of some alternative embodiments of the first aspect of the present application, an overlapping structure is formed at the overlapping portion between the aluminum fine grid segment 15a and the silver pad 15b. The overlapping structure includes a first overlapping portion 151 of the silver pad 15b and a second overlapping portion 152 of the aluminum fine grid segment 15a. Among them, the first overlapping portion 151 is closer to the positive main grid line 17 than the second overlapping portion 152.

[0084] In these examples, when preparing the electrode structure of the interdigitated back contact battery, the aluminum fine grid segment 15a can be prepared by printing with aluminum paste first, and then the silver pad 15b and the positive main grid line 17 can be prepared by printing with silver paste.

[0085] As Figure 8 shown, in another example of some alternative embodiments of the first aspect of the present application, an overlapping structure is formed at the overlapping portion between the aluminum fine grid segment 15a and the silver pad 15b. The overlapping structure includes a first overlapping portion 151 of the silver pad 15b and a second overlapping portion 152 of the aluminum fine grid segment 15a. Among them, the second overlapping portion 152 is closer to the positive main grid line 17 than the first overlapping portion 151.

[0086] In these examples, when preparing the electrode structure of the interdigitated back contact cell, a silver pad 15b can be prepared by silver paste printing first, a positive main grid line 17 can be prepared by silver paste printing, and then an aluminum fine grid segment 15a can be prepared by aluminum paste printing.

[0087] In some optional embodiments of the first aspect of the present application, in the lateral direction X, the overlapping structure is arranged at intervals with the positive main grid line 17, and the positive main grid line 17 is a silver grid line. In these embodiments, arranging the overlapping structure at intervals with the positive main grid line 17 can further avoid metal recombination caused by the contact between the positive main grid line 17 and the aluminum fine grid segment 15a. On the other hand, it can reduce the usage amount of silver paste and lower the production cost of the interdigitated back contact cell.

[0088] The second aspect of the present application provides an interdigitated back contact cell, and the electrode structure of the interdigitated back contact cell in the first aspect of the present application is arranged on the backlight surface of the back contact solar cell.

[0089] For the interdigitated back contact cell provided in the second aspect of the present application, power loss is reduced during use, the consumption of silver paste is small, the production cost is reduced, and the open circuit voltage Voc and fill factor FF of the cell are improved.

[0090] As Figure 9 shown and Figure 10 shown, in some optional embodiments of the second aspect of the present application, the interdigitated back contact cell includes a P-type silicon substrate 11. In the longitudinal direction Y, P-type regions 12 and N-type regions 13 are alternately and spacedly arranged on the backlight surface of the P-type silicon substrate 11. The interdigitated back contact cell further includes a passivation and antireflection layer 14. The passivation and antireflection layer 14 is arranged on the backlight side of the P-type silicon substrate 11 and is in contact with the backlight surface of the P-type silicon substrate 11. The positive fine grid lines 15 and the negative fine grid lines 16 are located in the same fine grid line wiring layer on the side of the passivation and antireflection layer 14 facing away from the P-type silicon substrate 11. The positive main grid line 17 and the negative main grid line 18 are located in the same main grid line wiring layer, and this main grid line wiring layer is located on the side of the above-mentioned fine grid line wiring layer facing away from the P-type silicon substrate 11. Each positive main grid line 17 extends along the longitudinal direction Y, is electrically connected to a plurality of positive fine grid lines 15, and is insulated from each negative fine grid line 16 through an insulating material 19. Each negative main grid line 18 extends along the longitudinal direction Y, is electrically connected to a plurality of negative fine grid lines 16, and is insulated from each positive fine grid line 15 through an insulating material 19.

[0091] In some other specific examples of the above embodiments, the positive fine grid line 15 is an electrically connected structure formed by overlapping a plurality of aluminum fine grid segments 15a arranged at intervals along the transverse direction X and silver pads 15b. Among them, the aluminum fine grid segment 15a is electrically connected to the P-type region 12 on the P-type silicon substrate 11 through a first via hole opened in the passivation and antireflection layer 14, and the silver pad 15b is in contact connection with the positive main grid line 17, but is not in contact with the P-type region 12. The negative fine grid line 16 is a continuous silver fine grid line extending along the transverse direction X. The negative fine grid line 16 is electrically connected to the N-type region 13 on the P-type silicon substrate 11 through a second via hole opened in the passivation and antireflection layer 14.

[0092] In some specific examples of the above embodiments, the positive fine grid line 15 is a continuous aluminum fine grid line extending along the transverse direction X. The positive fine grid line 15 is electrically connected to the P-type region 12 on the P-type silicon substrate 11 through a first via hole opened in the passivation and antireflection layer 14. The negative fine grid line 16 is a continuous silver fine grid line extending along the transverse direction X. The negative fine grid line 16 is electrically connected to the N-type region 13 on the P-type silicon substrate 11 through a second via hole opened in the passivation and antireflection layer 14, which is not shown in the figure.

Specific Embodiments

[0094] I. Specific Structures of the Interdigitated Back-Contact Battery in Each Embodiment and Comparative Example

[0095] Specific structure of the interdigitated back contact battery in Example 1:

[0096] As Figure 9 shown, the interdigitated back-contact battery includes a P-type silicon substrate 11. On the longitudinal direction Y, the P-type region 12 and the N-type region 13 are alternately and spacedly arranged on the backlight surface of the P-type silicon substrate 11. The interdigitated back-contact battery further includes a passivation and antireflection layer 14. The passivation and antireflection layer 14 is disposed on the backlight side of the P-type silicon substrate 11 and is in contact with the backlight surface of the P-type silicon substrate 11. The positive fine grid line 15 and the negative fine grid line 16 are located in the same fine grid line wiring layer on the side of the passivation and antireflection layer 14 facing away from the P-type silicon substrate 11. The positive main grid line 17 and the negative main grid line 18 are located in the same main grid line wiring layer, and this main grid line wiring layer is located on the side of the above fine grid line wiring layer facing away from the P-type silicon substrate 11. Each positive main grid line 17 extends along the longitudinal direction Y, is electrically connected to a plurality of positive fine grid lines 15, and is insulated from each negative fine grid line 16 through an insulating material 19. Each negative main grid line 18 extends along the longitudinal direction Y, is electrically connected to a plurality of negative fine grid lines 16, and is insulated from each positive fine grid line 15 through an insulating material 19.

[0097] In Embodiment 1, the number of positive fine grid lines 15 is 150, and the number of negative fine grid lines 16 is 150.

[0098] The insulating material 19 is an insulating glue generally used to isolate the positive fine grid line 15 and the negative fine grid line 16. The insulating glue includes components such as polyurethane acrylate oligomer and acrylate oligomer.

[0099] The positive fine grid line 15 is an electrically connected structure formed by overlapping the above-mentioned multiple aluminum fine grid segments 15a arranged at intervals along the transverse direction X and the silver pads 15b. Among them, the aluminum fine grid segment 15a is electrically connected to the P-type region 12 on the P-type silicon substrate 11 through the first via hole opened in the passivation and antireflection layer 14, and the silver pad 15b is in contact connection with the positive main grid line 17, but is not in contact with the P-type region 12. The negative fine grid line 16 is a continuous silver fine grid line extending along the transverse direction X. The negative fine grid line 16 is electrically connected to the N-type region 13 on the P-type silicon substrate 11 through the second via hole opened in the passivation and antireflection layer 14.

[0100] The positive electrode main grid line is a silver main grid line, the negative electrode main grid line 18 is a silver main grid line, and the negative electrode fine grid is a silver fine grid line.

[0101] In Example 1, the value of M of the positive electrode main grid line 17 of the interdigitated back contact battery is 1, and the value of N of the negative electrode main grid line 18 of the interdigitated back contact battery is 4.

[0102] Specific structure of the interdigitated back contact battery in Example 2:

[0103] As Figure 10 shown, the interdigitated back contact battery includes a P-type silicon substrate 11. In the longitudinal direction Y, the P-type regions 12 and the N-type regions 13 are alternately and spacedly arranged on the backlight surface of the P-type silicon substrate 11. The interdigitated back contact battery further includes a passivation and antireflection layer 14. The passivation and antireflection layer 14 is disposed on the backlight side of the P-type silicon substrate 11 and is in contact with the backlight surface of the P-type silicon substrate 11. The positive fine grid line 15 and the negative fine grid line 16 are located in the same fine grid line wiring layer on the side of the passivation and antireflection layer 14 facing away from the P-type silicon substrate 11. The positive electrode main grid line 17 and the negative electrode main grid line 18 are located in the same main grid line wiring layer, and this main grid line wiring layer is located on the side of the above-mentioned fine grid line wiring layer facing away from the P-type silicon substrate 11. Each positive electrode main grid line 17 extends along the longitudinal direction Y, is electrically connected to a plurality of positive fine grid lines 15 and is insulated from each negative fine grid line 16 through the insulating material 19. Each negative electrode main grid line 18 extends along the longitudinal direction Y, is electrically connected to a plurality of negative fine grid lines 16 and is insulated from each positive fine grid line 15 through the insulating material 19.

[0104] The positive fine grid line 15 is an electrically connected structure formed by overlapping a plurality of aluminum fine grid segments 15a arranged at intervals along the transverse direction X and a silver pad 15b. Among them, the aluminum fine grid segment 15a is electrically connected to the P-type region 12 on the P-type silicon substrate 11 through a first via hole opened in the passivation and antireflection layer 14, and the silver pad 15b is in contact connection with the positive main grid line 17, but is not in contact with the P-type region 12. The negative fine grid line 16 is a continuous silver fine grid line extending along the transverse direction X, and the negative fine grid line 16 is electrically connected to the N-type region 13 on the P-type silicon substrate 11 through a second via hole opened in the passivation and antireflection layer 14.

[0105] In the interdigitated back contact battery provided in Embodiment 2, M of the positive main grid line 17 is 3, and N of the negative main grid line 18 of the interdigitated back contact battery is 4.

[0106] The positive electrode main grid line is a silver main grid line, the negative main grid line 18 is a silver main grid line, and the negative electrode fine grid is a silver fine grid line.

[0107] Except for the different value of M of the positive main grid line 17, the battery structures of Embodiment 1 and Embodiment 2 are the same.

[0108] Specific structure of the interdigitated back contact battery in Comparative Example 1:

[0109] As Figure 11 and Figure 12 shown, the interdigitated back contact battery includes a P-type silicon substrate 11. On the longitudinal direction Y, the P-type regions 12 and the N-type regions 13 are alternately and spacedly arranged on the backlight surface of the P-type silicon substrate 11. The interdigitated back contact battery further includes a passivation and antireflection layer 14. The passivation and antireflection layer 14 is disposed on the backlight side of the P-type silicon substrate 11 and is in contact with the backlight surface of the P-type silicon substrate 11. The same fine grid line wiring layer where the positive fine grid line 15 and the negative fine grid line 16 are located is on the side of the passivation and antireflection layer 14 facing away from the P-type silicon substrate 11. The positive main grid line 17 and the negative main grid line 18 are located in the same main grid line wiring layer, and this main grid line wiring layer is on the side of the above-mentioned fine grid line wiring layer facing away from the P-type silicon substrate 11. Each positive main grid line 17 extends along the longitudinal direction Y, is electrically connected to a plurality of positive fine grid lines 15 through a plurality of silver pads 15b, and is insulated from each negative fine grid line 16 through an insulating material 19. In Comparative Example 1, the first side of the silver pad 15b facing the P-type silicon substrate 11 is in contact with the positive fine grid line 15, and the second side of the silver pad 15b facing away from the P-type silicon substrate 11 is in contact with the positive main grid line 17. Each negative main grid line 18 extends along the longitudinal direction Y, is electrically connected to a plurality of negative fine grid lines 16, and is insulated from each positive fine grid line 15 through an insulating material 19.

[0110] The positive fine grid line 15 is an aluminum fine grid line that extends continuously along the transverse X direction as a whole. The positive fine grid line 15 is electrically connected to the P-type region 12 on the P-type silicon substrate 11 through a first via hole opened in the passivation and antireflection layer 14. The negative fine grid line 16 is a silver fine grid line that extends continuously along the transverse X direction as a whole. The negative fine grid line 16 is electrically connected to the N-type region 13 on the P-type silicon substrate 11 through a second via hole opened in the passivation and antireflection layer 14.

[0111] For the interdigitated back contact cell provided in Comparative Example 1, the value of M for the positive main grid line 17 is 4, and the value of N for the negative main grid line 18 of the interdigitated back contact cell is 4. Moreover, the positive main grid line 17 and the negative main grid line 18 appear in pairs, and there is a symmetry axis perpendicular to the fine grid lines between a pair of positive main grid line 17 and negative main grid line 18. The dotted line extending along the longitudinal Y direction in the figure is the symmetry axis of a pair of positive main grid line 17 and negative main grid line 18.

[0112] The positive electrode main grid line is a silver main grid line, the negative main grid line 18 is a silver main grid line, and the negative electrode fine grid is a silver fine grid line.

[0113] It should be noted that: the numbers of the positive fine grid line 15 and the negative fine grid line 16 in Example 1, Example 2, and Comparative Example 1 are the same.

[0114] II. Performance test results of the interdigitated back contact cells in each example and comparative example

[0115] Table 1 discloses the electrical performance data and the silver paste consumption data of a single interdigitated back contact cell in each example and comparative example

[0116] Table 1

[0117]

[0118] Compared with Comparative Example 1, Example 1 and Example 2 reduce the number of positive main grid lines 17 (silver main grid lines), so that both Example 1 and Example 2 reduce the number of silver solder joints between the positive main grid line 17 and the positive fine grid line 15. The required number of silver pads 15b is reduced, the number of lap joints between the silver pad 15b and the aluminum fine grid segment 15a becomes smaller, and the total lap joint area between the silver pad 15b and the aluminum fine grid segment 15a is also smaller than the total lap joint area between the positive main grid line 17 and the positive fine grid line 15 in Comparative Example 1. Thus, Example 1 and Example 2 avoid the losses of Voc, FF, and Isc caused by severe metal recombination at the silver-aluminum lap joint in Comparative Example 1, and Example 1 and Example 2 have improvements in Voc, FF, Isc, and Eta.

[0119] Specifically, the ratio of the silver-aluminum lap joint area of Example 1, the silver-aluminum lap joint area of Example 2, and the silver-aluminum lap joint area of Comparative Example 1 is 1:3:4. As can be seen from Table 1, in terms of the short-circuit current Isc of the battery performance, the Isc values of Example 1, Example 2, and Comparative Example 1 decrease in sequence; in terms of the fill factor FF of the battery performance, both Example 1 and Example 2 are improved compared with Comparative Example 1. The fill factor FF is mainly affected by two factors, recombination (mainly including metal recombination) and resistance (mainly including series resistance). In Example 1, since the transmission path from the positive fine grid line 15 to the positive main grid line 17 is longer than that in Example 2, the series resistance of Example 1 is greater than that of Example 2, resulting in the FF value of Example 1 being slightly lower than that of Example 2; the Eta values of Example 1 and Example 2 are both greater than the Et value of Comparative Example 1, the battery conversion efficiency is improved, and the electrical performance of the interdigitated back contact battery is optimized.

[0120] The third aspect of the present application provides a solar cell module, including an interdigitated back contact battery string, which is formed by connecting a plurality of interdigitated back contact batteries provided by the second aspect of the present application in series with each other.

[0121] The solar cell module provided by the third aspect of the present application requires less silver paste and has a low preparation cost, and the electrical performance of the solar cell module is improved.

[0122] The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. An electrode structure of an interdigitated back contact battery, characterized in that, Including: Main grid lines, including M positive main grid lines and N negative main grid lines arranged at intervals in the transverse direction. Fine grid lines, including multiple positive fine grid lines and multiple negative fine grid lines arranged at intervals in the longitudinal direction. Each positive fine grid line continuously extends in the transverse direction as a whole and passes through the M positive main grid lines. Each negative fine grid line continuously extends in the transverse direction as a whole and passes through the N negative main grid lines. Wherein, the M positive main grid lines evenly divide each positive fine grid line in the transverse direction. Each positive fine grid line is equally divided into M + 1 segments by the M positive main grid lines. The sub-segments of the positive fine grid lines on both sides of each positive main grid line are of equal length, and each positive main grid line is electrically connected to the multiple positive fine grid lines. The electrical connection points of all the positive main grid lines and one positive fine grid line are all distributed within the line segment of the positive fine grid line. The N negative main grid lines evenly divide each negative fine grid line in the transverse direction. Each negative fine grid line is equally divided into N + 1 segments by the N negative main grid lines, and each negative main grid line is electrically connected to the multiple negative fine grid lines. The electrical connection points of all the negative main grid lines and one negative fine grid line are all distributed within the line segment of the negative fine grid line, and 1 ≤ M < N.

2. The electrode structure according to claim 1, characterized in that, In the transverse direction, the negative main grid lines are adjacently arranged on both sides of any positive main grid line.

3. The electrode structure according to claim 1, characterized in that, One of M and N is odd, and the other is even.

4. The electrode structure according to claim 1, characterized in that, Both M and N are odd or both are even, and M and N satisfy the following relationship: (N + 1) / (M + 1) ≠ positive integer.

5. The electrode structure according to claim 1, characterized in that, The M positive main grid lines include a central positive main grid line, and the connection lines between the central positive main grid line and the center points of each positive fine grid line coincide.

6. The electrode structure according to claim 1, characterized in that, The line width of the main grid lines ranges from 0.05 mm to 3 mm, and the line widths of the positive main grid lines and the negative main grid lines are equal.

7. The electrode structure according to any one of claims 1 to 6, characterized in that, The positive fine grid lines include multiple aluminum fine grid segments arranged at intervals in the transverse direction. The electrode structure further includes silver pads, which are arranged on the same layer as the aluminum fine grid segments. In the transverse direction, the silver pads overlap with two adjacent aluminum fine grid segments among the positive fine grid lines, so that multiple aluminum fine grid segments in the positive fine grid lines are electrically connected. The positive main grid lines, located on one side of the silver pads, are vertically connected to multiple positive fine grid lines through multiple silver pads in the longitudinal direction.

8. The electrode structure according to claim 7, characterized in that, The overlapping width between all the silver pads and the aluminum fine grid segments is from 0.1 mm to 0.5 mm.

9. The electrode structure according to claim 7, characterized in that, The overlapping part between the aluminum fine grid segment and the silver pad forms an overlapping structure, which includes a first overlapping part of the silver pad and a second overlapping part of the aluminum fine grid segment. Among them, The first overlapping part is closer to the positive main grid line than the second overlapping part, or the second overlapping part is closer to the positive main grid line than the first overlapping part.

10. The electrode structure according to claim 9, characterized in that, In the transverse direction, the overlapping structure is arranged at intervals with the positive main grid line, and the positive main grid line is a silver grid line.

11. An interdigitated back contact battery, characterized in that, The electrode structure as described in any one of claims 1 to 10 is provided on the backlight surface of the interdigitated back contact battery.

12. A solar cell module, characterized by comprising an interdigitated back contact battery string, and the interdigitated back contact battery string is formed by connecting a plurality of the interdigitated back contact batteries according to claim 11 in series.

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